JPH02270618A - Pressure control device for suspension - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to pressure control of vehicle suspensions.

In particular, the present invention relates to a device for controlling suspension pressure so as to suppress changes in vehicle body posture due to changes in vehicle driving conditions and the like.

(Prior art) For example, Japanese Unexamined Patent Publication No. 61-268509 and Japanese Utility Model Application No. 6
Publication No. 2-202404 proposes a suspension control device that detects changes in the posture of the vehicle body using a stroke sensor, calculates the deviation between the detected stroke value and a preset target stroke, and adjusts the suspension pressure according to this deviation. There is.

When such detection value reading/calculation/correction output processing is repeated at a predetermined period using a microprocessor, or when an analog electric circuit is used in place of the microprocessor, the detection signal line is passed through a low-pass filter with a predetermined time constant. The detection signal is smoothed in time series, and the rise and fall of the suspension pressure is controlled based on the smoothed signal.

(Problem to be Solved by the Invention) If the above-mentioned period or time constant is too short, the control operation becomes unstable, and the suspension pressure may oscillate (hunting) higher or lower than the target pressure.

If it is too long, the pressure control operation will be stabilized, but the deviation of the actual vehicle body posture from the target vehicle body posture will become large, and the period of mismatch between the seven vehicle postures will become longer.

The accuracy of vehicle attitude control decreases. Along with the above-mentioned period or time constant, the control gain (pressure correction amount/deviation) also affects the stability and control accuracy of pressure control; if the control gain is too small, the responsiveness of pressure control will be low, and if it is too large, the responsiveness of pressure control will be low. However, in order to avoid the suspension pressure from oscillating high or low relative to the target pressure (hunting) by suspension pressure control, Since the period or time constant of the sailing speed is set relatively long and the control gain is kept relatively low, the responsiveness and control accuracy of suspension pressure correction are relatively low. As a result, hunting in the suspension pressure is less likely to occur, but the suspension pressure is not properly controlled in response to changes in vehicle driving conditions or the lifting or dropping of the axle due to rough roads, resulting in poor riding comfort for the occupants.

An object of the present invention is to improve the responsiveness and control accuracy of suspension pressure correction.

[Structure of the invention]

(Means for Solving the Problems) The pressure control device of the present invention includes: a pressure source (1) for supplying pressure fluid to a suspension (100 fr) that expands and contracts according to the supplied pressure; Pressure control means (80fr) that is located between the suspension (100fr) and sets the suspension pressure to the target pressure; Height detection means (15fr) that detects the height of the vehicle body supported by the suspension (100fr); Specifies the reference height An instruction means (17) that generates height instruction information (He); a difference (DHT) in the height detected by the height detection means (15fr) with respect to the reference height indicated by the height instruction information (H); E
first correction amount calculation means (17) for calculating a first correction amount (CH) corresponding to HT2) at a predetermined period or time constant STI;
; Pressure detection means (13fr) for detecting suspension pressure (Pfr); Predetermined period or time constant S shorter than STI
At T2, the direction of change in the detected suspension pressure (pfr) is detected.

Corresponding to the direction of change, a second correction amount (5Ifr) that lowers the suspension pressure when the suspension pressure (pfr) is increasing, and increases it when it decreases.
a second correction amount calculation means (18) for calculating; and a pressure control means (80fr) for adding a pressure correction corresponding to the first correction amount and the second correction amount to the suspension pressure.
Target pressure setting means (18, 32, 33) for electrically energizing
; Note that symbols in parentheses indicate corresponding elements or corresponding parameter symbols in the embodiments described later.

(Function) First, the instruction means (17) generates height instruction information ()it) specifying a reference height, and the height detection means (1,5fr)
detects the height of the vehicle body supported by the suspension (100fr), and the first correction amount calculation means (17) detects the height detection means (15fr) relative to the reference height indicated by the height instruction information (Ht). Difference (E) between detected heights (D)IT)
The first correction amount (CH) corresponding to HT2) is calculated with a predetermined period or time constant STi, and the target pressure setting means (18, 32,
33) electrically energizes the pressure control means (80fr) to apply a pressure correction corresponding to the first correction amount to the suspension pressure, so that the pressure of the suspension (100fr) is updated at the STI period or time constant, and the STI In the time-series average over a longer time period, the vehicle height is maintained at the reference height.

That is, the vehicle body attitude is maintained at the reference attitude.

In such pressure control, control gain (CH/EH
When T2) is increased, the response is high, but the suspension pressure oscillates (oscillation or hunting) at high and low levels relative to the target pressure.
It becomes easier to do.

However, in the present invention, the second correction amount calculation means (18)
However, the direction of change in the suspension pressure (pfr) is detected at a predetermined period or time constant ST2 shorter than the STI, and if the suspension pressure (pfr) is increasing in the direction of change, the suspension pressure is decreased in the direction of lowering the suspension pressure. When the direction is the same, a second correction amount (SIfr) is calculated in the direction of increasing the pressure, and the target pressure setting means (18, 32, 33) controls the pressure so that it adds a pressure correction corresponding to the second correction amount to the suspension pressure. Since the means (80fr) is electrically energized, for example, when the suspension pressure starts to rise and this rise causes the vehicle height to rise, by the time this rise is suppressed by the feedback of the first correction amount, the suspension pressure will increase. is suppressed by feedback of the second correction amount, thereby suppressing an increase in vehicle height, and thereby suppressing the first correction amount. In other words, the period or time constant ST is shorter than the feedback of the first correction amount (correction amount based on the detected value of the vehicle height detector) with a relatively long period or time constant STL.
The feedback No. 2 acts quickly to suppress the suspension pressure correction amount (first correction amount). This suppression of the first correction amount acts only when the suspension pressure increases or decreases, so it acts at or immediately before the vehicle height changes. Therefore, conventionally, even when a relatively high control gain is set that tends to cause high and low vibrations (oscillations or hunting), the suspension pressure rise that causes such high and low vibrations, At the time of decrease, the correction amount (first correction amount) is automatically suppressed, so that such high and low vibrations are less likely to occur. That is, according to the present invention, a relatively high control gain can be set to realize stable and highly responsive pressure control.

Other objects and features of the present invention will become clear from the following description of embodiments with reference to the drawings.6 (Example) Fig. 1 shows an outline of the mechanism of a vehicle body support device. The pump is disposed in the engine room and is rotationally driven by the on-vehicle engine (not shown), sucks oil from the reservoir 2, and supplies the oil at a predetermined flow rate to the high-pressure boat 3 at a rotational speed higher than a predetermined speed. Exhale.

Radial pump high pressure boat 3 for suspension pressure supply
A pulsation absorbing accumulator 4° main check valve 50 and a relief valve 60m are connected to the high pressure boat 3 through the main check valve 50.
high pressure oil is supplied to the high pressure supply pipe 8.

The main check valve 50 prevents oil from flowing back from the high pressure supply pipe 8 to the high pressure boat 3 when the pressure in the high pressure boat 3 is lower than the pressure in the high pressure supply pipe 8.

The relief valve 60rn is one of the oil passages that return the high-pressure boat 3 to the reservoir 2 when the pressure of the high-pressure boat 3 exceeds a predetermined pressure. The pressure in the high-pressure boat 3 is maintained at a substantially constant pressure by supplying current to the reservoir return pipe 11.

The high pressure feed pipe 8 has a front axle suspension of 100fL.

A front wheel high pressure supply pipe 6 for supplying high pressure to the 100fr.

A rear wheel high pressure supply pipe 9 for supplying high pressure to the rear axle suspension 100rLv 100rr is in communication, and the front wheel high pressure supply pipe 6 has an accumulator 7 (for front wheels).The rear wheel high pressure supply pipe 9 has an accumulator 10 ( (for the rear axle) are connected.

A pressure control valve 80fr is connected to the front wheel high pressure supply pipe 6 via an oil filter.
However, the pressure in the front wheel high-pressure supply pipe 6 (hereinafter referred to as front axis line pressure) is regulated (reduced) to the required pressure (pressure crab suspension support pressure corresponding to the energizing current value of the electric coil) and the cut valve 70fr and the relief are activated. Give to valve 60fr.

When the pressure of the front wheel high pressure supply pipe 6 (front wheel side line pressure) is less than a predetermined low pressure, the cut valve 70fr.
R's output boat 84 (to the suspension) and the hollow piston rod 102fr of the shock absorber 101fr of the suspension 100fr are cut off.
) to the pressure control valve 80fr, and while the front wheel side line pressure is above a predetermined low pressure, the pressure control valve 80f
The output pressure (suspension giant support pressure) of r is directly supplied to the piston rod 102fr.

Relief valve 60fr is shock absorber 101
Limit the internal pressure of fr to below the upper limit. That is, when the pressure (suspension support pressure) of the output boat 84 of the pressure control valve 80fr exceeds a predetermined high pressure, the output boat 84 is made to flow through the reservoir return pipe 11, and the pressure control valve 80fr
maintain the pressure of the output boat substantially below a predetermined high pressure.

The relief valve 60fr is even better.

When the front right wheel bumps up from the road surface 1111 and the internal pressure of the shock absorber 10ffr rises shockingly,
It buffers the propagation of this impact to the pressure control valve 80fr, and when the internal pressure of the shock absorber 101fr rises impulsively, the internal pressure of the shock absorber 101fr is transferred to the reservoir return pipe 11 via the piston rod 100fr and the cut valve. released into the

Suspension 100fr roughly means shock absorber 101fr and I! Coil spring 119 for 1 rack
The pressure supplied into the shock absorber 101fr via the output boat 84 of the pressure control valve 80fr and the piston rod 102fr (pressure crab suspension support pressure regulated by the pressure control valve 80fr)
Support the vehicle body at a height (relative to the front right axle) corresponding to

The support pressure given to the shock absorber tOXfr is
It is detected by the pressure sensor 13fr, and the pressure sensor 13fr generates an analog signal indicating the detected support pressure.

A vehicle height sensor 15fr is attached to the vehicle body near the suspension 100fr, and a link connected to the rotor of the axle sensor 15fr is connected to the axle of the front right wheel. The vehicle height sensor 15fr generates an electric signal (digital data) indicating the vehicle height of the front right axle (height of the vehicle body relative to the wheels).
occurs.

Pressure control valve 80fL and cut valve 70 similar to the above
f L # Relief valve 60fL, vehicle height sensor 15
fL and a pressure sensor 13fL are similarly installed and assigned to the front left axle suspension 100fL, and a pressure control valve 80fL is connected to the front wheel high pressure supply pipe 6 to maintain the required pressure (support pressure). suspension 100f
The L shock absorber 101f is applied to the L piston rod 102fL.

Similar to the above, pressure control valve 80rr, cut valve Orr, relief valve 60rr, vehicle height sensor 15
Similarly, the pressure control valve 80rr is connected to the rear wheel high pressure supply pipe 9 to apply the required pressure (support pressure) to the suspension 100rr. 100rr shock absorber 101rr piston rod 102
Give to rr.

Furthermore, a pressure control valve 80rLt cut valve similar to the above? 0rLr Relief valve 60rLt Vehicle height sensor 15
Similarly, a pressure sensor 13rL and a pressure sensor 13rL are assigned to the front left wheel suspension 100rL, and a pressure control valve 80rL is connected to the rear wheel high pressure supply pipe 9 to adjust the required pressure (support pressure). ) suspension 100
r+, , to the piston rod 102rL of the shock absorber 101rL.

In this example, the engine is installed on the front wheel side.
Along with this, the hydraulic pump 1 is moved to the front wheel side (engine room).
equipped with hydraulic pump 1 to rear wheel suspension 1.
00rr, the piping length up to 100rL is "from hydraulic pump 1 to front wheel suspension 100fr.

It is longer than the piping length up to 100 fL. Therefore, the pressure drop due to the piping is large on the rear wheel side. If an oil leak occurs in the piping, the pressure drop on the rear axle side will be the largest. Therefore, the rear wheel high pressure supply A pressure sensor 13r- for line pressure detection is connected to the pipe 9. On the other hand, the pressure in the reservoir return pipe 11 is lowest at the end on the reservoir 2 side, and tends to increase as the distance from the reservoir 2 increases. As shown,
The pressure in the reservoir return pipe 11 is also detected by a pressure sensor 13rt on the rear wheel side.

A bypass valve 120 is connected to the rear wheel high pressure supply pipe 9. This bypass valve 120 regulates the pressure of the high pressure supply pipe 8 to a pressure corresponding to the current value of the electric coil (obtains the required line pressure). l stop)
When this occurs, the line pressure is reduced to substantially zero (atmospheric pressure in the reservoir 2 through the reservoir return pipe 11).
L +70rr, 70r L is turned off to prevent pressure loss in the shock absorber), lightening the load when restarting the engine (pump 1).

FIG. 2 shows the piston rod 1 of the shock absorber 101fr, showing an enlarged longitudinal section of the suspension 100fr.
A piston 103 fixed to the 02fr roughly divides the inside of the inner cylinder 104 into an upper chamber 105 and a lower chamber 106.

Suspension support pressure (hydraulic pressure) is supplied to the piston rod 102fr from the output port of the cut valve 70fr, and this pressure is applied to the side port 10 of the piston rod 102fr.
7 into the upper chamber 105 in the inner cylinder 104, and further through the upper and lower through holes 108 of the piston 103 into the lower chamber 10.
Join 6. A support pressure proportional to the product of this pressure and the cross-sectional area of the piston rod 102fr (rod radius squared x π) is applied to the piston rod 102fr.

The lower chamber 1.06 of the inner cylinder 104 is a damping valve device! It communicates with a space 110 above 109 . The upper space of the damping valve device 109 is divided into a lower chamber 112 and an upper chamber 113 by a piston 111. Oil in the upper space 110 flows into the lower chamber 112 through the damping valve device W109, but oil in the upper space 110 flows into the lower chamber 112 through the damping valve device W109. is filled with high pressure gas.

When the piston rod 102fr tries to relatively rapidly move downward into the inner cylinder 104 due to the thrust upward movement of the front right wheel, the internal pressure of the inner cylinder 104 suddenly increases, and the pressure in the upper space 110 also decreases to the lower chamber. The pressure is about to rise sharply higher than that of 112. At this time, the damping valve device! Oil flows from the upper space 110 to the lower chamber 112 through a check valve 109 that allows oil to flow from the upper space 110 to the lower chamber 112 at a predetermined pressure difference or higher, but blocks flow in the opposite direction. As a result, the piston 111 rises to buffer the impact (upward) applied from the wheels from propagating to the piston rod 102fr. In other words, to the car body, in front of the wheels! (ball thrusting) propagation is buffered.

When the piston rod 102fr relatively tries to come out above the inner cylinder 104 due to the sudden fall of the front right wheel, the internal pressure of the inner cylinder 104 suddenly decreases and the upper space 1
The pressure of 1G is about to suddenly become lower than the pressure in the lower chamber 112. At this time, the damping valve device 109.

Oil flows from the lower chamber 112 to the upper space 110 through a check valve that allows oil to flow from the lower chamber 112 to the upper space 110 at a predetermined pressure difference or higher, but prevents flow in the opposite direction. The piston 111 descends and the impulse I! is applied from the wheels!
It buffers the (downward) propagation to the piston rod 102fr. In other words, the front wheel I! to the vehicle body! The propagation of (downturn) will be buffered.

In addition, shock absorber 101 is used to raise the vehicle height, etc.
As the pressure applied to fr increases.

The pressure in the lower chamber 112 increases, causing the piston 111 to rise, and the piston 111 to be at a position corresponding to the vehicle body load.

Piston rod YO2 for internal information 104 such as while parking
When there is no relative vertical movement of fr, the seal between the inner cylinder 104 and the piston rod 102fr allows the inner cylinder 10
4, there is virtually no oil leakage into the outer cylinder 114.However, in order to reduce the vertical movement load on the piston rod 102fr, the seal is designed such that only a small amount of oil leaks when the piston rod 102fr moves up and down. It is said to have the sealing properties of The oil leaking into the outer cylinder 114 is returned to the reservoir 2 through the outer cylinder 114, through the drain 14fr (FIG. 1) which is open to the atmosphere, and through the drain return pipe I2 (FIG. 1) which is a second return pipe. The reservoir 2 is equipped with a level sensor 28 (FIG. 1), and when the oil level in the reservoir 2 is below the lower limit, the level sensor 28 generates a signal (oil shortage signal) indicating this.

The structures of the other suspensions 100f L, 100rr and 100r L are also the same as those of the suspension 100 described above.
The structure is substantially similar to that of fr.

FIG. 3 shows an enlarged longitudinal section of the pressure control valve 80fr.

The sleeve 81 has a spool storage hole in its center, and the line pressure boat 8 is provided on the inner surface of the spool storage hole.
A ring-shaped groove 83 through which the low-pressure boat 85 communicates and a ring-shaped groove 86 through which the low-pressure boat 85 communicates are formed. An output port 84 is opened between these ring-shaped grooves 83 and 86. The spool 90 inserted into the spool storage hole has a ring-shaped groove 91 having a width corresponding to the distance between the right edge of the groove 83 and the left edge of the groove 86 in the middle of its side circumferential surface. A valve housing hole is formed in the left end of the spool 90, and this valve housing hole communicates with the groove 91. The valve storage hole has
A valve body 93 pushed by a compression coil spring 92 is inserted.

This valve body 93 has a through orifice at its center, and the space of the groove 91 (output port 84) communicates with the space in which the valve body 93 and the compression coil spring 92 are accommodated. Therefore, the spool 90 receives the pressure of the output port 84 (IN pressure, the pressure on the suspension 100fr) at its left end, and thereby receives a force that drives it to the right. In addition, the output port 84
When the pressure of the output port 84 becomes shockingly high, the valve body 93 moves to the left against the pushing force of the compression coil spring 92, creating a buffer space at the right end of the valve body 93. At the time of the shocking rise, this shocking rising pressure is not immediately applied to the left end face of the spool 90, and the valve body 93
has the effect of buffering the rightward movement of the spool 90 against an impulsive pressure increase in the output port 84, and vice versa.

Output boat 84. This has the effect of buffering the leftward movement of the spool gO against the impulsive pressure drop.

The pressure of the target pressure space 88 communicating with the high pressure boat 87 via the orifice 88f is applied to the right end surface of the spool 90, and due to this pressure, the spool 90 receives a force that drives it to the left. Line pressure is supplied to the high pressure boat 87 , and the target pressure space 88 communicates with the low pressure boat 89 through a flow path 94 , and a needle valve 95 defines a communication opening of this flow path 94 . When the needle valve 95 closes the flow path 94, the high pressure boat 87 flows through the orifice 88f.
The pressure in the target pressure space 88 communicated with the high pressure boat 87 becomes the pressure (line pressure), and the spool 90 is driven to the left, whereby the groove 91 of the spool 90 communicates with the groove 83 (line pressure port 82). and groove 91 (output port 84)
The pressure increases, and this is transmitted to the left side of the valve body 93, giving a rightward driving force to the left end of the spool 90. needle valve 95
When the flow path 94 is fully opened, the pressure in the target pressure space 88 is narrowed by the orifice 88f, so it is significantly lower than the pressure (line pressure) in the high pressure boat 87, and the spool 90 moves to the right. Accordingly, the groove 9 of the spool 90
1 communicates with the groove 86 (low-pressure boat 85), the pressure in the groove 91 (output port 84) decreases, this is transmitted to the left of the valve body 93, and the rightward driving force of the left end of the spool 90 decreases. In this way, the spool 90 is at a position where the pressure in the target pressure space 80 and the pressure in the output boat 84 are balanced. That is, a pressure substantially proportional to the pressure in target pressure space 88 appears at output port 84 .

The pressure in the target pressure space 88 is determined by the position of the needle valve 95 and is substantially inversely proportional to the distance of the needle valve 95 from the flow path 94. An inversely proportional pressure appears.

The needle valve 95 passes through a fixed core 96 of magnetic material. The right end of the fixed core 96 has a truncated conical shape, and the end face of the magnetic plunger 97 in the shape of a conical hole with a bottom is opposed to this right end face. A needle valve 95 is fixed to this plunger 97. The fixed core 96 and plunger 97 are
It enters inside the bobbin around which the electric coil 99 is wound.

When the electric coil 99 is energized, magnetic flux flows through the loop of the fixed core 96 - magnetic yoke 98a - magnetic end plate 98b - plunger 97 - fixed core 96, and the plunger 97 is attracted to the fixed core 96 and moves to the left. However, when the needle valve 95 approaches the flow path 94 (the distance becomes shorter),
The left end of the needle valve 95 receives the pressure of the target pressure space 88 as the right driving force, and the right end of the needle valve 95 is at atmospheric pressure through the low pressure boat 98c that is released to the atmosphere. As a result, the needle valve 95 receives a right driving force corresponding to the pressure value (which corresponds to the position of the needle valve 95), and as a result, the needle valve 95 is substantially inversely proportional to the energizing current value of the electric coil 9g with respect to the flow path 94. It becomes the distance. In order to make the relationship between current value and distance linear, one of the fixed core and the plunger is shaped like a truncated cone, and the other is shaped like a corresponding conical hole with a bottom, as described above.

As a result of the above, a pressure substantially proportional to the current value flowing through the electric coil 99 appears at the output port 84 .

This pressure control valve 80fr is operated when the current applied is within a predetermined range.
A pressure proportional to the pressure is outputted to the output port 84.

FIG. 4 shows an enlarged longitudinal section of the cut valve 70fr.

A line pressure boat 72. Pressure adjustment capo door 3. The oil drain boat 74 and the output port door 5 are in communication. Line pressure port 7
2 and the pressure regulation input port door 3 is a ring-shaped first guide 7.
6, the pressure regulation input port door 3 and the output port door 50
Between is a cylindrical guide 77a, ? 7b and 77c
separated by. The oil drain port 74 is connected to the second guide 77
communicates with the ring-shaped groove on the outer periphery of the second guide 77a, 7
The oil leaked around the outer circumferences of 7b and 77c is returned to the return pipe 11.

A spool 78 pushed leftward by a compression coil spring 79 passes through the first and second guides 76, 77a to 77c, and line pressure is applied to the left end surface of the spool 78.

The left end of the spool 78 has entered. The guide hole of the central projection of the second guide 77c communicates with the return pipe 11 through the ring-shaped groove on the outer periphery of the second guide 77c and the oil drain port 74. When the line pressure is less than a predetermined low pressure, the spool 78 is driven to the leftmost position by the repulsive force of the compression coil spring 79, as shown in FIG.

The output port door 5 and the pressure regulation input port door 3 are blocked by the spool 78 completely closing the inner opening of the second guide 77a. Line pressure is below a predetermined low pressure”-1;
Then, due to this pressure, the spool 79 begins to be driven to the right against the repulsive force of the compression coil spring 79, and the spool 79 is positioned at the rightmost position (fully opened) at a pressure higher than the predetermined low pressure, that is, the spool 79 is moved to the rightmost position (fully opened). 8 is the second guide 77a
When the pressure regulation input port door 3 communicates with the output port door 5 and the line pressure (line pressure boat 72) rises to a predetermined low pressure, the cut valve 70fr moves to the right from the inner opening of the pressure regulation input port door 3 (pressure control When the line pressure (boat 72) starts to flow between the pressure regulation output of the valve 80fr and the output port door 5 (shock absorber xoxfr), the pressure regulation input port door 3 (pressure regulation output of the pressure control valve 80fr) increases further. and output port door 5 (shift absorber 101f
Fully open between r). When line pressure decreases,
In the opposite case, when the line pressure becomes less than the predetermined low pressure, the output port door 5 (shock absorber 101fr) is completely cut off from the pressure regulation input port door 3 (pressure regulation output of the pressure control valve 80fr).

FIG. 5 shows an enlarged longitudinal section of the relief valve 60fr, and the input port 2 and the low pressure boat 63 are opened in the valve housing hole of the valve base 61. A cylindrical first guide 64 and a second guide 67 are inserted into the valve storage hole, and the input port 2 communicates with the inner space of the first guide 64 through the filter 65. A valve body 66 having an orifice in the center is inserted into the first guide 64, and the valve body 66 is pushed to the left by a compression coil spring 66a. The space in the first guide 64 that accommodates the valve body 66 and the compression coil spring 66a is
It communicates with the input port 2 through the orifice of the spring seat 66b, and also communicates with the second guide 6 through the opening of the spring seat 66b.
It communicates with the inner space of 7. The conical valve body 68 is pushed to the left by the repulsive force of the compression coil spring 69, and the spring seat 6
The opening of 6b is closed. Input Portro 2 pressure (
When the control pressure) was less than a predetermined high pressure, it communicated with the input port 2 through the orifice of the valve body 66. The pressure in the coil spring 66a storage space causes the compression coil spring 6
Since the repulsive force of the fifth valve body 68 is relatively lower than that of the fifth valve body 68,
As shown in the figure, the central opening of the valve seat 66b is closed,
Therefore, the output port 2 is connected to the low pressure boat 63 and the hole 6.
It is cut off from the inner space of the second guide 67, which communicates through 7a. That is, the output port 2 is cut off from the low pressure boat 63.

When the pressure (control pressure) of the input port 2 rises to a predetermined high pressure, this pressure passes through the orifice of the valve body 66 and reaches the valve seat 66.
b, the valve body 68 begins to be driven to the right by this pressure, and when the pressure of the input port 2 further increases, the valve body 68 is driven to the rightmost side. That is, the pressure of the input port 2 is released to the low pressure boat 63, and the control pressure is suppressed to a predetermined high pressure level or less.

Note that when high pressure is applied to the input port 2, the valve body 66 is driven to the right, and the input port 2 moves toward the first guide 64.
It communicates with the valve storage space of the base body 61 through the side port 64a and communicates with the low pressure boat 63, and since this passage area is large, a sudden pressure rise (pressure shock) of the output port 2 is prevented.
be attacked.

FIG. 6 shows an enlarged longitudinal section of the main check valve 50. An input port 52 and an output port 53 communicate with a valve housing hole formed in the valve base 51. A cylindrical valve seat 54 with a bottom is housed in the valve housing hole 1 , and a ball valve 57 pushed by a compression coil spring 56 closes a communication port 55 of the valve seat 54 . When the pressure of the ball valve 5 is higher than the pressure of the output port 53, the ball valve 5
7 is pushed to the right by the pressure of the input port 52 and opens into the communication port 55.
open, i.e. from input port 52 to output port 53
Oil flows in this direction. However, when the pressure at the output port 53 is higher than the pressure at the input port 52, the ball valve 57 closes the communication port, so that oil does not flow from the output port 53 toward the input boat 52.

FIG. 7 shows an enlarged longitudinal section of the bypass valve 120.
The input port 121 communicates with the inner space of the first guide 123, and a compression coil spring 124b is connected to the inner space.
The valve body 1248 pushed to the left is housed. This valve body 124a has an orifice at the center of the left end surface, and the input port 121 is connected to the first guide 1 through this orifice.
23 inner spaces are connected. The inner space has a flow path 122
It communicates with the low pressure boat 122 through the flow path 1
22b is opened and closed by a needle valve 125.

The solenoid device consisting of the needle valve 125 to the electric coil 129 includes the needle valve 95 to the electric coil 9 shown in FIG.
The solenoid device has the same structure and dimensions as the solenoid device No. 9 (common design for the pressure control valve and the bypass valve), and the distance of the needle valve 125 with respect to the orifice 122b is substantially inversely proportional to the energizing current value of the electric coil 129. Since the flow opening degree of the orifice 122b is inversely proportional to this distance, the flow from the input port 121 passes through the orifice of the valve body 124a, passes through the inner space of the first guide 123, and enters the orifice 12.
The oil flow rate passing through 2b to the low pressure boat 122 is
It is proportional to the differential pressure across the orifice on the left end surface of the valve body 124a.

As a result of the above, the pressure at the input port 121 is
The pressure is substantially proportional to the current value of 29. This bypass valve 120 sets the pressure (line pressure) of the input port 21 within a predetermined range of one current and is proportional to the pressure. Also, when the ignition switch is off (engine stopped: pump 1 stopped), the electric coil 129
By stopping the energization, the needle valve 125 moves to the rightmost side, and the input port 121 (line pressure) becomes a low pressure near the return pressure.

When the pressure of the input port 121 rises shockingly,
The valve body 124a is driven to the right by receiving this pressure on the left end face, and the low pressure boat 122a communicates with the low pressure boat 122.
communicates with the input port 121. Low pressure boat 122a
is a relatively large opening, so the * of input port 21
*The increased pressure immediately escapes to the low pressure boat 122a.

The relief valve 60■ is the relief valve 60f mentioned above.
It has the same structure as r, but has a conical valve body (68:
A compression coil spring (69) presses the spring (Fig. 5).

The spring force is said to be a little small, and the input port (6
2) (pressure of the high pressure boat 3), the relief valve 60fr transfers the pressure of the input port 2 to the low pressure boat 63.
When the pressure is less than the predetermined high pressure, which is slightly lower than the pressure to be released to the low pressure boat (63), the output port (62)
). When the pressure at the input port (62) exceeds a predetermined high pressure, the valve body (68) is driven to the rightmost direction. That is, the pressure of the input port (62) is released to the low pressure boat (63), and the pressure of the high pressure boat 3 is suppressed to a predetermined high pressure or less.

With the above configuration, in the vehicle body support device shown in FIG. 1, the main check valve 50 supplies oil from the high pressure boat 3 to the high pressure supply pipe 8, but prevents backflow from the high pressure supply pipe 8 to the high pressure boat 3. do.

The relief valve 60m suppresses the pressure of the high-pressure boat 3, that is, the pressure of the high-pressure supply pipe 8, to a predetermined high pressure or less.

When the pressure in the high-pressure boat 3 rises impulsively, it is released to the return pipe 11 to buffer the impulsive pressure from propagating to the high-pressure supply pipe 8.

The bypass valve 120 substantially linearly controls the pressure in the rear wheel high pressure supply pipe 9 within a predetermined range, and maintains the pressure in the rear wheel high pressure supply pipe 9 at a predetermined constant pressure during normal operation. This constant pressure control is performed by the bypass valve 120 with reference to the detected pressure of the pressure sensor 13r+a. This is done by flE flow value control. Furthermore, when there is a shocking pressure rise in the rear wheel suspension, it is released to the return pipe 11 to prevent it from propagating to the high pressure supply pipe 8. Furthermore, when the ignition switch is open (engine stopped: pump 1 stopped), 1 current is cut off, and the rear wheel high pressure supply pipe 9 is connected to the return pipe 11.
To provide flow to the rear wheel, the pressure in the rear wheel high-pressure supply pipe 9 (high-pressure supply pipe 8) is released.

Pressure control valve 80fr, 80f L, 80rr, 80r
L is an electric coil (99) so as to apply the required support pressure to the suspension by suspension pressure control.
The energizing current value is controlled, and the required support pressure is output to the output port (84). When impact pressure from the suspension propagates to the output port (84), it is buffered to suppress disturbances in the pressure control spool (91) (disturbances in the output pressure). In other words, the required pressure is stably applied to the suspension.

Cut valve 70fr, 70f L, 70rr, 70
r L is line pressure (front wheel high pressure supply pipe 6. rear wheel high pressure supply pipe 9
) is below a predetermined low pressure, the suspension supply pressure line (between the output port 84 of the pressure control valve and the suspension) is shut off to prevent pressure from escaping from the suspension, and when the line pressure is above the predetermined low pressure, Fully open the supply pressure line. This automatically prevents an abnormal drop in suspension pressure when line pressure is low.

Relief valve 60fr, 60f L, 60rr, 6
0rL limits the pressure (mainly suspension pressure) in the suspension supply pressure line (between the output port 84 of the pressure control valve and the suspension) to less than the high pressure upper limit, and prevents wheel thrusting or when heavy objects are loaded. When there is a shocking pressure increase in the supply pressure line (suspension) due to throwing, etc., this is released to the return pipe 11, which alleviates the impact on the suspension and improves the durability of the hydraulic line connected to the suspension and the mechanical elements connected to it. enhance sex.

FIG. 8 shows how the vehicle's driving condition, posture, etc. are determined in accordance with the states of various switches and sensors mounted on the vehicle, and the required pressure of each suspension shown in FIG. 1 is calculated based on the vehicle body posture. An outline of the configuration of the electrical control system for setting the desired values is shown below.

The aforementioned vehicle height sensor 15f L, 15fr, 15r L
, 15rr are connected to a low-pass filter 31i, and the low-pass filter 311 detects the high frequency (noise) of the vehicle height detection signal (analog signal) of each vehicle height sensor.
The amplifier 301 amplifies the thus shaped vehicle height signal to a predetermined level range, and the A/D converter (IC) 29
Give to z.

Pressure sensor 13f that detects the oil pressure of each suspension
A low-pass filter 312 is connected to L, 13fr, 13r L, and 13rr, and this low-pass filter 312 receives the pressure detection signal (
The high frequency (noise) component of the analog F signal is cut off, and the relatively high frequency vibration component is smoothed, and the amplifier 302 amplifies the pressure signal thus shaped to a predetermined level range. It is applied to an A/D converter (rc) 292.

Pressure sensor 1.3ra that detects the pressure of the rear wheel high pressure supply pipe 9
A low-pass filter 313 is connected to the pressure sensor 13rt that detects the pressure on the rear wheel side of the return pipe 11. The pressure signal thus shaped is sent to the amplifier 303.
A/D converter (IC)
Give to 293.

Additionally, a longitudinal acceleration sensor 16p mounted on the vehicle detects acceleration in the longitudinal direction of the vehicle (longitudinal acceleration; +: acceleration, -2 deceleration) and lateral acceleration in the lateral direction of the vehicle (+: acceleration from left to right, -2). A low-pass filter 313 is also used in the lateral acceleration sensor 16r that detects acceleration from the right to the left.
This low-pass filter 313 blocks the high frequency (noise) component of the pressure detection signal (analog signal) of each acceleration sensor, smoothes the relatively high frequency vibration component, and The amplifier 303 amplifies the shaped acceleration signal to a predetermined level range, and
/D converter (IC) 29a.

Pressure control valve 80f L, 80fr, 80r L, 8
The coil driver 33 is connected to the 0rr electric coil 99 and the electric coil 129 of the bypass valve 120. The coil driver 33 includes a switching circuit that energizes each of the electric coils, and a current detection circuit that detects the current value of each of the electric coils and generates an analog signal indicating the current value.
C) In response to the on (energized)/off (de-energized) instruction from 32, when on is instructed, conduction is established between the electric coil and the output end of the constant current circuit, and when off is instructed. Then, an analog voltage indicating the detected current value is constantly applied to the A/D converter (IC) 293.

The duty controller 32 stores (latches) energizing current value designation data given from the microprocessor (hereinafter referred to as CPU) 18 to each of the electric coils (each of the pressure control valves and the bypass valve), and provides feedback. The detected current value is sent to the A/D converter (IC) 2.
93 to the CPU 18, and the CPU 18 adjusts the 2 on/off duty so that the specified current value is reached.
A time-series on/off instruction corresponding to this duty is given to the coil driver 33.

The A/D converters 291 to 293 have four input ports (however, ANA!J'/voltage indicating the detected current value of the pressure control valve and bypass valve is input from the coil driver 33 to 29.). , A/D with built-in sample and hold circuit
It is a conversion IC.

When a conversion instruction is given from the CPTJ18, the analog voltage of the input boat is held in the sample hold circuit, converted to digital data (vehicle height data, pressure data, acceleration data), and the digital data is converted into a clock pulse given by the CPU18. It is synchronously and serially transferred to the CPU 18.

This analog voltage hold, digital conversion, and digital data transfer are performed sequentially for input ports 1 to 4. That is, when the CPU 18 instructs -.degree. A/D conversion, the analog voltages of the four input ports are sequentially converted into digital data, and the digital data is sequentially transferred to the CPU 18.

CP K, J 18 are connected to the CPU 17 in a data transmission/reception relationship.

CP T, J 17 indicates that the brake pedal is depressed (
Signal indicating H)/no (L), ignition switch 20
A signal indicating open (L)/close (H) of A rotary encoder 2 that is coupled and generates a first set of pulses and a second set of pulses whose phase is shifted by 90 degrees from the first set of pulses after rotation through a predetermined small angle.
6.

Detects the first and second sets of pulses, data generated by the absolute encoder 27 that is coupled to the rotating shaft of the engine's throttle valve and generates 3-bit data indicating the throttle valve opening, and the oil level in the reservoir 2. A signal from the level sensor 28 (H: below the lower limit level, L: level higher than the lower limit level) is provided, and signals from other sensors (not shown) are also provided from the input/output circuit 34. An indicator such as a warning light is connected to the input/output circuit 34, and when an abnormality is determined in suspension pressure control, CrUl, 7 is input/output.
The output circuit 34 is instructed to display the display.

A low-capacity backup power supply circuit 23 is connected to the on-vehicle battery 19, and this supplies a constant voltage to the CPU 17, so that while the voltage of the battery 19 is above a predetermined value, the CPU 17 is always in an operating state. It holds data in its internal memory.

A high capacity constant voltage power supply circuit 21 is connected to the on-vehicle battery 19 via an ignition switch 20.
This power supply circuit 21 supplies low constant voltage 4j to weak electric elements and circuits such as the CPU 18, and also provides a low-pass filter 31.
A high constant ffi pressure is applied to circuits such as 1 to 313 and the input/output circuit 34.

The ignition switch 20 has a self-holding relay 22.
The contacts L/-22 are connected in parallel, and the CPU 17 turns on (closes) and off (opens) L/-22.

The CPUs 17 and 18 store programs for controlling the pressures of the respective suspensions. According to this progera 11, the CPU 18 mainly operates a vehicle height sensor 15f provided in the suspension system shown in FIG.
L, 15fr, 15r L, 15rr and pressure sensor 13f L, 1.3fr, 13r L
, 13rr, 13rm, 13rt,.

Also, reading the detected values of the longitudinal acceleration sensor 16ρ and the lateral acceleration sensor 16r of the vehicle 1-, and the pressure control valve 8
The values of currents applied to OfL, 80fr, 80rL, 80rr and the electric coils (99, 129) of the bypass valve 120 are controlled.

From when the ignition switch 2o is closed until it is opened and immediately after the ignition switch 2o is opened, the CPU 17 sets/cancels the line pressure of the suspension system (Fig. 1), determines the vehicle operating state, and processes the determination results. The system calculates the required pressure (pressure that should be set for each suspension) to establish the corresponding appropriate vehicle height and body posture, receives various detected values from the CPU 18 to determine the vehicle driving state, and sets the required pressure. The current value required to
Give to U18.

Hereinafter, with reference to the flowcharts shown in Figure 9a et seq.
Explaining the control operations of CPU1.7 and 18 Table 1 Register Signed data Contents symbol of written data
Initial pressure of shock absorber 101fr PR1,, o PrLo
Initial pressure PR of shock absorber 101r L
ROPrr (Initial pressure of 1 shock absorber 101rr DPHDph Rear wheel side pressure of high pressure line 8 D
PL DPL Rear wheel side pressure of return pipe 11 SS Ss Steering angular speed SA
Sa Rudder angle acceleration TP Tp
Throttle opening TS Ts
Throttle opening/closing speed STI STI CP
Period at which U17 reads the detected value VS Vs
Vehicle speed PG pg Longitudinal acceleration (sensor 16
ρ) PA Pa Rate of change in longitudinal acceleration R, G R, g Lateral acceleration (sensor 1
6r) RA Ra Rate of change of lateral acceleration DFL DfL Vehicle height DFR of front left axle
Dfr Vehicle height of front right wheel DRL Dr
L Vehicle height of rear left axle DRR, Drr
Vehicle height of rear right wheel HT He Heap target value PT Pt Pitching target value RT R,t Rolling target value WT wt Warb target value, but
First, in order to facilitate understanding, the symbols assigned to the main registers assigned to the internal memory of the CPU 17 and the contents of the main data written to each register are summarized in Table 1.

In addition, in the flowcharts of the drawings and the explanations to be given later, the register symbols themselves may sometimes mean the contents of the registers.6 First, reference is made to FIG. 9a. When it is powered on (step 1: the backup power supply circuit 23 generates a constant voltage: the battery 19 is attached to the vehicle body), the CPU
17 sets internal registers, counters, timers, etc. to the contents of the initial standby state.

Outputs a signal level to the output port to set the initial standby state (no electrical energization of each mechanism element) ).

Next, the CPU 17 checks whether the ignition switch 20 is closed (3), and if it is open,
Wait until it closes.

When the ignition switch 20 is closed, the coil of the relay 22 is energized and the contacts of the self-holding relay 22 are closed (4). is connected to the battery 19, and the power supply circuit 21 provides a low constant voltage to weak electric elements and electric circuits such as the CPU 18, and a high constant voltage to circuits such as the low-pass filters 311 to 313 and the input/output circuit 34. , the CPU 18, etc. are also electrically energized and in an operating state, but since the relay 22 is turned on, the power supply circuit 21 is also connected to the battery 19 via the relay contact, so from then on, if the ignition switch 20 is open, all of the electrical circuitry shown in FIG. 8 remains electrically energized and operational until CP tJ ) 7 turns off relay 22.

When the CPU 17 turns on the relay 22, it allows the interrupt process to be executed in response to the arrival of the pulse signal to the interrupt input ports ASRO to ASR2 (5). An overview of the responded interrupt processing will be explained. First, we will explain the interrupt processing (input port ASR2) in response to a pulse generated by the vehicle speed synchronization pulse generator 25. When the 1 generator 25 generates 1 pulse, in response to this, the interrupt processing (ASR2) proceeds.
The contents of the vehicle speed clock register at that time are read, the vehicle speed clock register is restarted, the vehicle speed value is calculated from the read contents (cycle of the vehicle speed synchronization pulse), and the previous vehicle speed held until then is calculated. Value Vs obtained by taking the calculated value and weighted average
is written in the vehicle speed register VS, and the process returns to the step immediately before proceeding to this interrupt processing (return).

By executing this interrupt process (ASR2), data Vs indicating the current vehicle speed (time-series smoothed value of the vehicle speed calculation value) is always held in the vehicle speed register vS.

To explain the interrupt processing (input port ASRO) in response to the first set of generated pulses of the rotary encoder 36 for detecting the rotational direction of the steering shaft, the first
This interrupt processing (
ASRO) and interrupt processing (ASRO) in response to the rising edge.
When proceeding to RO), write ■] to the flag register for determining the direction of one rotation, and in response to the falling edge, interrupt processing (
ASRO), the flag register is cleared (L is written) and the process returns to the step immediately before proceeding to this interrupt process.

Note that -1 of the first set of pulses of the rotary encoder 26
When the rising edge of the second ffl pulse appears next to the rising edge of the second set of pulses (flag register = H), the steering shaft is being driven to the left; When the rising edge of the set of pulses is cursed, the steering shaft is being driven clockwise.

To explain the interrupt processing (input port ASRI) of the rotary encoder 36 for detecting the rotational speed (steering angular speed) of the steering shaft in response to the second set of generated pulses, the second set of pulses (falling edge) is When it arrives,
In response to this, the process proceeds to interrupt processing (ASRI), reads the contents of the steering timing register at that time, restarts the steering timing register, and uses the read contents (period of the steering angular velocity synchronization pulse) to determine the rotation direction. If the content of the flag register for is H, the + (left rotation) sign is
If the content of the flag register is L, a sign of - (clockwise rotation) is added, the speed value (including directions + and -) is calculated from it, and the speed of the number of cruises held so far is calculated. The value Ss obtained by taking the calculated value and the weighted average is written into the steering angular velocity register SS, and the process returns to the step immediately before proceeding to this interrupt process (return).

By executing this interrupt processing (ASRI), data Ss indicating the current steering angular velocity (time-series smoothed value of the speed calculation value) is always stored in the steering angular velocity register SS (+ indicates counterclockwise rotation, -
(clockwise rotation) is maintained.

When the CPU 17 allows the above-mentioned interrupt processing, the CPU 17
Check whether U18 is giving a ready signal (6) and suspension pressure control is instructed (S
(OS on) or not (SCS off) (7)
.

By the way, the CPU 18 is powered on itself (
When the ignition switch 20 is closed), the internal registers and counters are initialized.

Set the timer, etc. to the content of the initial standby state, and set the signal level to the output boat to set the initial standby state to 1 (no electrical energization of each element) (the duty controller 32 specifies all electric coils off). data) is output (12th a
82) in the figure. Then, maximum current value data that completely closes the bypass valve 120 is given to the duty controller 32 to instruct the bypass valve 120 to be energized. With the above settings, the pressure control valves 80fL, 80fr, 8
At 0r L and 80rr, the current value is zero, and the pressure of the return pipe 11 is output to the output boat (84), but since the bypass valve 120 is fully closed, the ignition switch 20 is closed ( When the pump 1 is rotationally driven by the engine rotation, the high pressure supply pipe 8. The pressures in the front wheel high pressure supply pipe 6 (accumulator 7) and the rear wheel high pressure supply pipe 9 (accumulator 10) begin to rise.

Thereafter, the CPU 18 sets the vehicle height sensors 15f L , 15fr , 15r L , 15 at the second setting cycle ST2.
rr, pressure sensor 13fL.

! 3fr, 13ri-, 13rr, 13r+s, 13
rt, longitudinal acceleration sensor 16p and lateral acceleration sensor 1
Detected value of 6r, and.

Read the current detection value of the coil driver 33 (12th
89 in figure a) Update the internal register and write it to the CPU 17.
When cptyx7 requests the transfer of detection data, the data in the internal register at that time is transferred to the CPU 17 (104 and 105 in FIG. 12b).

Pressure control valve 80f L, 80fr, 80r L, 8
0rr and the energizing current value data of the bypass valve 120, the bypass valve 120 directly supplies it to the duty controller 32, but the pressure control valve 80f L
, 80fr, 80r L.

The FFJ1 current value data of 80rr is written to the internal register (103 in Fig. 12b), corrected to correspond to the rate of change in suspension pressure, and provided to the duty controller 32 (91 to 91 in Fig. 12a). 93).

Now, when the CPU 18 is giving a busy signal in the check at step 6.7, the CPU 17 waits there and executes the standby processing (8 to 11).

In the standby process (8), the presence or absence of an abnormality is determined by referring to the pressure detection values of all pressure sensors, the current detection values of all electric coils of the coil driver 33, and the vehicle height detection values of all vehicle height sensors;
When the suspension is controlled, the pressure is set during standby (stopped) (bypass valve 120 is de-energized, fully opened, and the pressure control valve is de-energized), and if an abnormality is determined, a notification corresponding to the abnormality and pressure setting (bypass Valve 120 de-energized,
Pressure control valve de-energizes) (10), and if no abnormality is determined, cancels abnormality processing (clears abnormality notification) (11)
).

Now, when the CPU 18 notifies the CPU 18 that it is ready, it cancels the above-mentioned abnormal processing (which may not be executed in some cases) (12), and cancels the above-mentioned standby processing (which may not be executed in some cases) (13).

Then, the CPU 17 sends the pressure sensor 13 to the CPU 18.
Instruct the transfer of the detected pressure data DPh of r■, receive it, and write it to the register DPH (14), so that the detected pressure (rear wheel side pressure of the high pressure supply pipe 8) Dph is set to a predetermined value Pph (cut valve 70f L, 70fr, 70r L, 70rr
Check whether the line pressure has risen to a certain level (lower than the predetermined low pressure at which the line starts to open) or higher (
15). If the line pressure has not risen, return to step 6.

When the line pressure rises, the CP'U17 tells the CPU18 to
Detected pressure (initial pressure) data of pressure sensors 13fLj3fr, 13rL, 13rr PfLOrPfro +PrLO
Instruct the transfer of +PrrO, receive them, and write them to registers PFLo, PFRo, PRL, ,PRR,
(16).

Then, the energizing current value data required to obtain the required pressure in one area (Table 1) of the internal ROM is stored in the register PFL.
o, PFRO, PRL (1, Contents of PRRo PfLp
, PfrO, PrLo, and Prro to determine the current value Ihf to be applied to the electric coil 99 required to output the pressure PfL to the output port 84 of the pressure control valve 80fL.
L, the current value Ihfr required to output the pressure PfrO to the output port of the pressure control valve 80fr, the current value IhrL required to output the pressure PrLo to the output port of the pressure control valve 80rL, and the pressure PrrO under pressure control. The energizing current value Ihrr required to be output to the output port of the valve 80rr is read from Table 1, and output registers IHfL, IHfr, IHrL and IH
rr (17) and transfer the data in these output registers to the CPU 18.

The CPU 18 receives these data and provides them to the duty controller 32.

The duty controller 32 has energizing current value data I
hfL, Ihfr, Ihr, and Ihrr
is memorized (latched), and the current value (detected value) of the pressure control valve 80fL, which is fed back by the CPU 18, is I.
hfL, adjust the on (energized)/off (de-energized) duty of the electric coil 99 of the pressure control valve 80fL, and send a time series on/off instruction corresponding to the adjusted duty to the coil driver. 33, pressure control valve 8
0f L, and the other pressure control valve 80fr.

9 time series on/off instructions are given to the coil driver 33 to perform similar duty control for 11QrL and 80rr.

With this current setting, the pressure control valve 80fL.

80fr, 80rL, and 80rr are substantially PfLo and Pfr, respectively, when the line pressure is higher than a predetermined low pressure.
The pressure of o+PrLO+PrrQ is output to the output port (84), and in response to the line pressure rising to a predetermined low pressure or higher, the cut valves 70fL, 70fr, 70rL,
When 70rr is opened, the pressure of each suspension at that time (initial pressure) PfLo +PfrO+PrLO,
A pressure substantially equal to PrrO is applied to the cut valve 70f L
, 70fr, 70r L , pressure control valve 80f L , 80fr, 80r L , through 70rr
Suspension 100fL, 100f from 80rr
r, 100rL, 100rr.

Therefore, only when the ignition switch 20 changes from open (engine stopped: pump 1 stopped) to closed (pump 1 driven), the cut valves 70f L and 70fr are activated.

70r L and 70rr are open (line pressure is above the predetermined low pressure).

When the hydraulic line of the suspension communicates with the output port of the pressure control valve, the output pressure of the pressure control valve and the suspension pressure are substantially equal, preventing sudden pressure fluctuations in the suspension, that is, shocking changes in the vehicle body attitude. Does not occur.

The above is the pressure control valve 80 when the ignition switch 20 is switched from open to closed (immediately after starting the engine).
The initial output pressure settings are f L , 80fr, 80r L , and 80rr.

Next, the CPU 17 starts the timer STI for the ST1 time period. STY is the contents of 5 registers and 1 register, and register STI contains data STI indicating a first setting cycle that is longer than the second setting cycle ST2 in which the CPU 18 reads detected values.
is written. For example, STI is 40-400m5
ec, and Sr1 is about 8 to 401 sec.

After starting the timer STI, the CPU 17 reads the status (20).

In this case, the opening/closing signal of the ignition switch 20, the opening/closing signal of the brake pedal depression detection switch BPS, the throttle opening data of the absolute encoder 27, and the signal of the reservoir level detection switch 28 are read and written to the internal register, and the CPU 18 to transfer the detection data to the vehicle height sensor 15f L t
15fr t 15r L+15rr vehicle height detection data D f Ly D fr t Dr L I D
rr + pressure sensor 13f, 13frt 13rL
+13rr, 13rm.

13r pressure detection data PfL, Pfr, PrL, P
rr.

Pr+s, Prt, and pressure control valve and bypass valve 80fL, 80fr, 80rL, 80rr
, 120 and writes it into the internal register. Then, by referring to these read values, it is determined whether it is abnormal or normal, and if it is abnormal, the process proceeds to step 8.

In the case of normality, the CPU 17 next performs line pressure control (LP
Execute C).

In this case, the absolute value and polarity (high/low) of the deviation of the detection line pressure Prm from the reference pressure (a fixed value slightly lower than the relief pressure (predetermined high pressure) of the relief valve 60■) are calculated, and the current bypass valve 120 A correction value corresponding to the deviation to zero the deviation is added to the energizing current value flowing through the bypass valve 120 to calculate the current energizing current value of the bypass valve 120, and this is written in the output register.

Note that the contents of this output register will be determined in step 3, which will be described later.
6, the data is transferred to the CPU 18.

By this line pressure control J (LPG), the pressure of the rear wheel high-pressure supply pipe 9 is adjusted to the leaf pressure of the relief valve 60m (
The value of the current flowing through the bypass valve 120 is controlled so that it becomes a predetermined value that is slightly lower than the predetermined high pressure (predetermined high pressure).

Reference is now made to Figure 9b. Above line pressure control (LPC)
After completing the process, the CPU 17 checks whether the switch 20 is open or closed (22).

If the switch 20 is open, a stop process (23) is performed, the relay 22 is turned off, and the interrupt ASRO-A is activated.
Prohibit SR2. In the stop process (23), the bypass valve 120 is first de-energized and fully opened (line pressure is released to the return pipe 11).

Switch 20 is opened (engine stopped: pump 1 stopped), high pressure discharge from pump 1 is stopped, bypass valve 120 is fully opened, and high pressure supply pipe 8. Front wheel high pressure supply pipe 6
(Accumulator 7) and rear wheel high pressure supply pipe 9 (Accumulator 10) become the pressure of return pipe 11, and the pressure of return pipe 11 is released to reservoir 2,
The high pressure supply pipe 8 and the like become atmospheric pressure.

High pressure supply pipe 8 etc. are cut pulp 70f L + 70f
At the timing when the pressure of r*70r L and 70rr reaches a predetermined low pressure or lower that changes to complete shutoff, the CPU 17 switches the pressure control valves 80f L, 80fr, 80r L
, 80rr are de-energized.

Now, when the switch 20 is closed, parameters indicating the vehicle running state are calculated (25).

That is, by reading the content Ss of the steering angular speed register SS, [value read this time Ss - value read last time]/D1=
Sa (steering angle acceleration) is calculated and written to register SA. Then, [throttle opening TP read in this time, read in subroutine 20 - throttle opening read last time]
= Ts (throttle opening/closing speed), and register T
Write to S 6 Then, [read in subroutine 20,
The longitudinal acceleration pg read this time - the longitudinal acceleration read last time]; Pa (rate of change in longitudinal acceleration) is calculated and written to the register PA, and [read in subroutine 20].

Lateral acceleration Rg read this time - Lateral acceleration read last time) =
Ra (rate of change in lateral acceleration) is calculated and written to register RA.

Next, the CPU 17 executes the vehicle height deviation calculation J (31) to calculate the suspension pressure correction amount (first correction amount: each (for each suspension).The details of this will be described later with reference to FIG. 10a.

The CPU 17 executes "Pitching/Rolling Prediction Calculation J (32)" next to "Vehicle Height Deviation Calculation J (31)",
The suspension pressure correction amount (second correction amount: for each suspension) corresponding to the vertical and lateral acceleration actually applied to the vehicle body is calculated, and [suspension initial pressure (PfLO, P
fro +PrLo, Prr(1) "First correction amount 10th correction amount" (calculated intermediate value: for each suspension) is calculated.The details of this will be described later with reference to the Job diagram.

Next, the CPU 17 executes "pressure correction J (33),
The "calculated intermediate value" is corrected in accordance with the line pressure (high pressure) detected by the pressure sensor 13r+s and the return pressure (low pressure) detected by the pressure sensor 13rt. Details of this will be described later with reference to FIG. 10c.

Next, the CPU 17 uses the pressure/current conversion J (34) to convert the corrected "calculated intermediate value" (for each suspension) into the pressure control valves (80f L, 80fr, 80r
Lt80rr). The details will be described later with reference to FIG. 10d.

Next, the CPU 17 calculates a turning warp correction value (current correction value) corresponding to the lateral acceleration Rg and the steering speed Ss in the warp correction J (35).

Add to this the current value that should flow through the pressure control valve.

Details of this will be described later with reference to FIG. 10e.

CP T, J 17 +! Next, at r output j (36),
The current value that should be passed through the pressure control valves calculated as above is transferred to the CPU 18 for each pressure control valve, and the current value that should be passed to the bypass valve 120 calculated in the above-mentioned "line pressure control J (LPC)" is transferred to the CPU 18. Bypass valve 12
Addressed to 0, it is transferred to the CPU 18.

At this point, the CPU 17 has completed all tasks included in one cycle of suspension pressure control.

Therefore, we wait for the timer ST to time out (3
7) When the time has elapsed, the process returns to step 19, restarts the timer ST, and executes the suspension pressure control task for the next cycle.

Due to the suspension pressure control operation of the CPU 17 explained above, the CPU 18 is requested (subroutine 20) to transfer the sensor detection value in the STI cycle (first setting cycle), and in response, the CPU 18 2 The sensor detection value data read at the set cycle ST2 and subjected to past several read values and weighted average smoothing is transferred to the CPU 17 (89 and 90 in Fig. 12a and 1 in Fig. 12b).
05).

In addition, the CPU 18 receives current value data to flow through each of the pressure control valves and the bypass valve 120 from the CPU 17 in the STI cycle, and each time the CPU 18 receives this transfer, the current value data to flow through the bypass valve 120. is output as is to the duty controller 32 (latch)
However, the current value data addressed to the pressure control valve is updated in the register (103 in Figure 1.2b), and the duty controller 32 is updated with the data corresponding to the suspension pressure change rate at the second setting cycle ST2. Calculate the correction amount, add this correction amount to the current value data written in the register, and give the current value data corrected in this way (88 to 9 in Fig. 12a).
3).

Therefore, the duty controller 32 updates the target current value data in the STI period while updating the bypass valve 120.
The energization duty is controlled so that the current value (the current value detected by the coil driver 33) becomes the target current value.
Such energization duty control is performed for each pressure control valve in the ST2 period.

Referring to FIG. 10a, to explain the contents of "vehicle height deviation calculation j (31)," first, the outline will be as follows:
Vehicle height detection value Df of 15fr, 15rL, 15rr
L.

Dfr, DrL, Drr (Register DPI, , DFR
.

DRL, DRR contents), heap (height) DHT, pitch (difference between front wheel side vehicle height and rear wheel side vehicle height) DPT, roll (right wheel side vehicle height and right wheel side vehicle height) difference)D
RT and warp (the difference between the sum of the front right axle height and the rear left wheel height and the sum of the front left axle height and the rear right wheel height) DWT are calculated.

That is, each axle vehicle height (registers DFL, DFR).

DRL, DRR), and attitude parameters of the entire vehicle (heap DHT, pitch DPT, roll DR).
T and warped DWT).

DHT=DFL+DFR+DRL+DRR.

DPT=-(DFL+DFR)+(DRL+DRR).

DRT= (DFL-DFR)+(DRL-DRR)
.

DWT= (DFL-DFR)-(DRL-DRR)
The calculation of DPT is executed by "Calculation of pitching error CP" (51), the calculation of DRT is executed by "Calculation of rolling error CR (52)", and the calculation of DWT is executed by "Calculation of warp error CW". Execute with J(53).

Then, in "Calculation of heap error CH (50), the target heap H is derived from the vehicle speed Vg, and the calculated heap D
HT calculates the heap error amount for the target heap Ht, performs PID processing on the calculated heap error amount for PID (proportional, integral, differential) control, and performs heap correction ff1cH (first correction amount) corresponding to the heap error. ) is calculated.

Similarly, in "Calculation of pitching error CP" (51), the target pitch Pt is derived from the longitudinal acceleration pg, the pitch error amount of the calculated pitch DPT with respect to the target pitch pt is calculated, and PID (proportional, integral) is calculated.

For differential) control, the calculated pitch error amount is used as PID.
Processing is performed to calculate the pitch correction amount cp corresponding to the pitch error.

Similarly, [Calculation of rolling error CR (at 521,
The target roll Rt is derived from the lateral accelerations R and g, and the roll error amount of the calculated roll DRT with respect to the target roll Rt is calculated, and PID (proportional, integral) is calculated.

For differential) control, the calculated roll error amount is used as PID.
Processing is performed to calculate a roll correction amount CR corresponding to roll error.

Similarly, in "Calculation of warp error CW (53), the amount of warp error of the calculated warp DWT with respect to the target warp Wt is calculated with the target warp W set as zero, and the amount of warp error with respect to the target warp Wt is calculated.
For (proportional, integral, differential) control, the calculated warp error amount is subjected to PID processing, and the warp correction amount CWt corresponding to the warp error is calculated! -Calculate. Note that when the absolute value of the calculated warp error amount (DWT because the target warp is zero) is less than a predetermined value (within the allowable range), the warp error amount to be subjected to PID processing is zero, and when it exceeds the predetermined value. niP
Let the warp error amount for ID processing be -DWT.

To explain in detail the contents of "Heap error CH calculation J (50)," the CPU 1.7 first reads the target heap Ht corresponding to the vehicle speed Vs from one area (table 2H) of the internal ROM and stores it in the heap. Target value register it
(39).

As shown in Table 2HJ in FIG. 10a, the target heap HL (vehicle height reference value) associated with the vehicle speed vs is a high value Htl when the vehicle speed Vs is 80 km/h or less; is a low value Ht2 at high speeds of 120 km/11 or more, but in the range where Vs exceeds 80 km/h and is less than 120 km/h, the target value changes linearly (a curve may be used) with respect to the vehicle speed Vg. ing.

To change the target value linearly in this way, for example, if the target value is changed to Htl at 100 Ks/h or less, and the target value is changed in one step to 1-it2 at 100 m/h or more, When Vs is around 100/h,
This is to prevent the target heap from changing greatly in stages due to a slight change in the speed of Vs, causing the vehicle height to frequently rise and fall significantly at high speeds, resulting in poor vehicle height stability. According to the settings of table 2H above.

Since the target value changes only slightly due to a slight change in the vehicle speed Vs, the change in the vehicle height target value is small.
Increased vehicle height stability.

The CPU 17 then calculates the heap DHT mentioned above (4
0), and writes the contents of register EHT2, which has written the heap error amount calculated last time, to register EHTI (41), calculates the current heap error amount HT-DHT, and writes this to register EHT2. Enter (42).

As a result of the above, the register ET (Tl has the previous value (before Sr1))
The current heap error amount is stored in the register EHT2. Next, the CPU 17 writes the contents of the register ITH2, in which the error integral value up to the previous time has been written, into the register ITold (43), and calculates the current PID correction amount ITh using the following equation.

ITh = Kh 1・E) lT2 +Kh2・(E
HT2+Kh3 ・ITI! 1)+Kha・Kh,
・(E(1cho2-EHTI) is hl・EHT2,
This is the P (proportional) term of the PID calculation, Khl is the coefficient of the proportional term, and EHT2 is the contents of register E)IT2 (current heap error amount).

Kh2・(E)lT2+Kha・I1 old) is the I (integral) term, Kh2 is the coefficient of the integral term, and lTl11 is the correction amount integral value up to the previous time (correction amount output from initial pressure settings 16 to 18) , Kh3 is a weighting coefficient between the current error amount EHT2 and the correction amount integral value ITHI.

Kh4・Kh,・(EHT2−EHTI) is a D (differential) term, and the coefficient of the differential term is Kh4・Kh, but Kh4 uses the value associated with the vehicle speed Vs, and K
hs uses a value associated with the steering angular velocity Ss.

That is, from one area of the internal ROM (table 3H),
Vehicle speed correction coefficient K associated with the vehicle speed Vs at that time
h4, and read out the steering angular velocity correction coefficient Kh5 corresponding to the steering angular velocity Vs at that time from one area (table 4H) of the internal ROM, and calculate the product K.
Let h, · ni, be the coefficient of the differential term.

As shown in Table 3HJ in Figure 10a, the vehicle speed correction coefficient h4 is roughly a larger value as the vehicle speed Vs is higher, and the weight of the differential term is increased. This is a correction term that attempts to quickly bring this value within the target value.The higher the vehicle speed, the faster the speed of vehicle height change in response to disturbances, so it is increased according to the vehicle speed.On the other hand,
Vehicle speed Vg is above a certain level (40KIL in table 3H)
/h), if the brake is pressed/released, the accelerator pedal is used to accelerate/decelerate, the steering wheel is rotated to turn/unturn, etc., the change in the vehicle's attitude becomes sudden and extremely large. An excessively large differential term that quickly compensates for sudden changes in attitude will degrade vehicle height control stability. Therefore, the vehicle speed correction coefficient Kh4 in the table 3H changes more broadly when the vehicle speed Vs is lower, and changes smaller as the vehicle speed Vs becomes higher. That is, when the vehicle speed Vs is low, the weight of the differential term changes greatly with respect to changes in vehicle speed, but when the vehicle speed Vs is high, the weight change of the differential term with respect to changes in vehicle speed is small.

As shown in Table 4HJ in Fig. 10a, the steering angular velocity correction coefficient h5 is roughly a larger value as the steering angular velocity Ss is higher, and the weight of the differential term is increased. This is a correction term that attempts to quickly bring the change into the target value with respect to changes in the steering angle speed Ss.The higher the steering angular speed Ss is, the faster the vehicle height changes in response to disturbances, so it is increased according to the steering angular speed. When the angular velocity Ss is below a certain level (50'7m5ec or below in Table 4H), the change in the traveling direction is extremely gradual and the weighting of the differential term is small.
Above 50°1m5ec and below 400°/rssec, the vehicle height changes at a speed substantially proportional to the steering angular speed Ss. At steering angular speeds of 400°/+1s6c or higher, the change in vehicle body attitude becomes rapid and extremely large, and an excessive differential term that quickly compensates for such a sudden change in attitude is dangerous because the stability of vehicle height control is compromised. becomes. Therefore, the coefficient Kh5 of the differential term corresponding to the steering angular velocity Ss is Ss
is a constant value below 50'/@sec, and 50'/@sec is a constant value.
When exceeding l1sec and below 400°/m5ec, the value is set to a high value substantially proportional to Ss, and when exceeding 400°#wsec, it is set to a constant value of the value at 400''/m5ee.

The differential term Kh4・Kh,・(EHT2−
EHTI), the coefficient h4 is increased in accordance with the vehicle speed Vs, and the coefficient Kh is increased in accordance with the steering angular speed S.
By increasing the value corresponding to s, weighted differential control corresponding to vehicle speed v5 and steering angular speed Ss is realized, and highly stable vehicle height control is realized with respect to fluctuations in vehicle speed Vs and steering angular speed Vs.

As described above, when the heap error correction amount ITh is calculated by the PID calculation (44), the CPU 17 stores the calculated heap error correction amount ITh in the register ITH2 (45).
).

Next, to this correction amount, h is added to the weighting coefficient of the heap error correction amount.
Multiply by a (weighting of the pitch error correction amount, roll error correction amount, and warp error correction amount described later: contribution ratio in the total correction amount), and the heap error register CH
write to.

When the heap error CH calculation (50) is executed as described above, the CPU 17 executes the "pitching error CP calculation".
Execute (51), calculate the pitch error correction amount CP in the same way as the heap error CH, and calculate the pitch error correction amount CP in the pitch error register C.
In this case, the pitch target value PT corresponding to the heap target value HT is written to the internal RO of C:PU17.
Data PL (target value according to the longitudinal acceleration pg) corresponding to the longitudinal acceleration Pg at that time is read out and obtained from one area of M (table 2P).

FIG. 11a shows the contents of table 2P. The pitch target value pt corresponding to the superimposed acceleration pg is in the direction of canceling out (decreasing) the pitch appearing due to the longitudinal acceleration Pg.
In the region a, the target pitch is increased (decreased) as the longitudinal acceleration Pg increases (decreases), aiming at energy conservation, and in the region b, the pitch target value is decreased because an abnormal pg may indicate a sensor abnormality. This is to prevent a pg target value from being given even though pg has not actually occurred. The other arithmetic processing operations are the same as the contents of the above-mentioned "heap error CH operation J (50),"
Step 39 HT, Ht, l! 1-PT.

Pt, and the DHT calculation formula in step 40 is replaced with the above-mentioned D
EHTI in step 41.

Replace Elf D2 with EPTI, EPT2, step 4
2 EHT2. HT, DHT to EPT2. PT, DPT
, I TH+, , I TH2 in step 43 are replaced with ITPI, ITP2, and IT in subroutine 44 is replaced with
Replace the hW output formula with a pitch error correction amount ITp calculation formula that has a completely corresponding relationship therewith, replace table 3H with a coefficient table (3P) for calculating the pitch correction amount ITp,
Table 4H is also replaced with a coefficient table (4P) for pitch correction 1ITp calculation, and ITH2, ITh in step 45
is replaced with ITP2゜ITp, and CH in step 46 is
By replacing 16 +ITh with CP, Kp, .

Next, the CPU 17 executes “Rolling error CR calculation J (
52), calculate the roll error correction amount CR in the same way as the heap error CH, and register it in the roll error register CR.
In this case, the roll target value RT corresponding to the heap target value HT is written to the data Rt corresponding to the lateral acceleration Rg at that time, (lateral acceleration R , g) is obtained by reading out the roll target value corresponding to g.

FIG. 11b shows the contents of table 2R. Lateral acceleration R
The roll target value Rt corresponding to g is in the direction of offsetting (decreasing) the roll cursed by the lateral acceleration Rg, and the region a is aimed at energy saving by increasing the target roll as the lateral acceleration Rg increases (decreases). In the area b, there is a possibility that the sensor is abnormal due to the abnormal Rg, so the roll target value is reduced to prevent the roll target value from being given even though no Rg actually occurs. The other calculation processing operations are the same as the contents of the calculation J (50) of the above-mentioned [heap error CI (HT, Ht; in step 39).

Rt, and the DHT calculation formula in step 40 is replaced with the above-mentioned D
RT! EHTI, EH in step 41
ERT T2],,ERT2Lm! and step 42
EHT2. HT, DHT to ERT2. Replace ITHI and ITH2 in step 43 with RT and DPT, and replace ITHI and ITH2 in step 43 with ITRI.
, lTR2, and replace the ITh calculation formula of subroutine 44 with the roll error correction amount IT, which has a completely corresponding relationship.
Replace table 3H with the r calculation formula and calculate the roll correction amount IT
Replace with the coefficient table (3R) for calculating r.

Table 4H is also replaced with a coefficient table (4R) for calculating the roll correction amount ITp, and ITH2, IT in step 45
Replace h with lTR2, ITr, and C in step 46.
CR H, Khs, I Th.

Kr6. By replacing it with ITr, a flowchart showing the contents of "Roll error CR calculation J (51)" appears. The CPU 17 executes the process shown in this flowchart.

Next, the CPU 17 calculates the r warp error CW” (53
) to calculate the warp error correction amount CW in the same way as the heap error CH and write it into the warp error register CW. In addition, in this, the warp target value PW corresponding to the heap target value HT is set to zero. ing. Other arithmetic processing operations are described in “Heap error CH operation J (50)”.
The content is the same as that of step 39, replacing HT, Ht with WT, 0, replacing the DHT calculation formula of step 40 with the above-mentioned DWT calculation formula, and replacing E HT 1 of step 41 with the above-mentioned DWT calculation formula.
.

Replace EHT2 with EWT 1 and EWT2, and change the contents of step 42 so that when the absolute value of DWT is less than or equal to the predetermined value WO1 (within the allowable range), WT is set to O, and when it exceeds Wllll, WT is set to -DWT. Register EW
Change the content to be written to T2, ITHI in step 43,
ITH2 is replaced with ITWI, ITW2, and the ITh calculation formula of subroutine 44 is replaced with a warp error correction amount IT- calculation formula that has a completely corresponding relationship, and Table 3H
is the coefficient table (3W) for calculating the warp correction amount ITr.
Replace it with Table 4! (also replaced with the coefficient table (4v) for calculating the warp correction amount ITw, and
TH2, iTh to ITW2. ITw, and CH, Kh6, ITh in step 46 are replaced with CW.

By replacing it with "s t I Tt++," the flowchart showing the contents of the two-way calculation J (53) of the warp error CW is cursed.The CPU 17 executes the processing represented by this flowchart.

As described above, after calculating the heap error correction amount CH, pitch error correction ff1cP, roll error correction amount CR, and warp error correction amount WP, the CPU 17 converts these correction amounts into the suspension pressure correction amount E for each axle.
Hf L (addressed to suspension 1.00fL), E
Hfr (to 100fr) # E Hr L (10
0r (addressed to L), E + (rr (addressed to 100rr)). That is, the suspension pressure correction amount is calculated as follows.

E Hf L = Kf L ・Kh7 (1/4) (CH
CP+CR+CW).

E Hfr =Kfr-Kh7・(1/4)・(Ctl
-CP-CR-CV).

E Hr L = Kr L-Kh7'(1/4)'
(CH+CP+CR-CW).

EHrr= to rr' to h7 (1/4) (CH+CP-
CR+CW) coefficient Kf L , Kfr, Kr L , K
rr is the suspension 100f L with respect to the line pressure reference point 13rm and the return pressure reference point 13rt;
This is due to the difference in piping length of 100fr, 100r L, and 100rr. This is a correction coefficient for compensating for suspension supply pressure deviation. Kh7 is a coefficient for increasing or decreasing the vehicle height deviation correction amount in accordance with the steering angular speed Ss, and is
17 (Table 5) in correspondence with the steering angular velocity Ss. Rudder angular speed S
If s is large, a large change in posture is expected, and an increase in the amount of posture error is expected.

Therefore, the coefficient h7 is approximately set large in proportion to the steering angular speed Ss. However, the steering angular speed Ss is below a certain level (50°/m5ec or below in Table 5)
In this case, the change in the direction of travel is extremely gradual and the change in attitude is small and gradual, exceeding 50''/m5ec and 400'.
/wasec or less, the attitude change appears at a speed substantially proportional to the steering angular speed Ss.

At a steering angular velocity exceeding 400°/wsec, the change in vehicle body attitude becomes rapid and extremely large, and an excessive correction amount that quickly compensates for such a sudden attitude change will degrade vehicle height control stability.

Therefore, the correction coefficient Kh7 corresponding to the steering angular velocity Ss is set to a constant value when Ss is 50"7asec or less, and
” S over 1m5ec and below 400°/vasec
It is set to a high value substantially proportional to s, and when it exceeds 400@7m5ec, it is set to a constant value of the value at 400°/m5ec.

Next, the contents of the pitching/rolling prediction calculation IIj (32) will be explained with reference to FIG. The current vehicle body posture is determined (feedback) from the current vehicle height 2 longitudinal acceleration and lateral acceleration, and the suspension pressure is adjusted to maintain the current vehicle body posture at the predetermined appropriate level! (feedback control), whereas the pitching/rolling prediction calculation J (32) roughly attempts to control the longitudinal and lateral acceleration of the vehicle body.
This is intended to suppress changes in longitudinal acceleration Pg and lateral acceleration Rg of the vehicle body.

The CPU 17 first calculates a correction amount CGT for suppressing a change in pitch due to a change in longitudinal acceleration pg (55
~58).

In this case, the contents of the register GPT2 in which the previous pg-compatible correction amount is written are stored in the register GPT14.
:Write (55), read the correction amount apr corresponding to Vs and Pg from the internal ROM (7) 1 area (table 6) and write it to the register GPT2 (57).

The data Gpt in Table 6 is grouped using Vs as an index, and the CPU 17 specifies the group using V and s, and then selects the data Gpt corresponding to pg in the specified group.
For each group that is assigned to a smaller Vs, the insensitive fa width (width of Gpt=0 in table 6 shown in FIG. 3) is set larger. b is a region where the gain is increased as the longitudinal acceleration Pg increases and control performance is improved, and C is a region where control performance is degraded because more than the sensor is considered.

Next, the CPU 17 calculates a correction amount CGP for suppressing a change in the longitudinal acceleration pg using the following equation and writes it into the register CGP (58).

CGP = nigpa ・CKgp 1 ・GP d2
+ Kgp 2 ・(GPT2- GPTI))G
PT2 is the contents of register G P T 2, and this time,
This is the correction amount apt read from Table 6.

GPTI is the content of register GPTI, and is the correction amount read out from table 6 last time. P (proportional) term Kg
gpt of P+-GPT2 is the coefficient of the proportional term.

In the D (differential) term KgP2・(GPT2-GPTI), gP2 is the coefficient of the differential term, and this coefficient KgP2 is
An area of internal ROM corresponding to vehicle speed Vs (Table 7)
This is what was read from. As shown in "Table 7" in FIG. 10b, the coefficient KgP2 generally has a larger value as the vehicle speed Vs becomes higher, and increases the weight of the differential term. This is because the differential term is a correction term that tries to quickly suppress changes in the longitudinal acceleration pg. This is because the longitudinal acceleration Pg changes quickly, so it is necessary to respond to this fast change and quickly suppress it. On the other hand, when the vehicle speed Vs exceeds a certain level, if the brake is depressed/released, the accelerator pedal is used to accelerate/decelerate, the steering wheel is rotated to turn/return, etc., the longitudinal acceleration Pg
If the change in the value of y is sudden and extremely large, and an excessively large differential term is used to quickly suppress such a sudden change, the stability of suppressing acceleration around 1 will deteriorate. Therefore table 7
More specifically, the coefficient KgP2 changes significantly when the vehicle speed Vs is low, and
It is assumed that s is constant when it is equal to or greater than a predetermined value. In other words, vehicle speed Vs
When Vs is low, the weight of the differential term changes greatly with respect to changes in vehicle speed, but when the vehicle speed Vs is high, the weight of the differential term does not change with respect to changes in vehicle speed.

The calculated correction amount CGP for suppressing changes in longitudinal acceleration Pg is a pitch compensation iT amount for the suspension, and K
gP3 is a weighting coefficient for roll correction amounts CGR and GES, which will be described later.

Next, the CPU 17 calculates a correction amount CGR for suppressing changes in roll due to changes in lateral acceleration Pg (that is, suppressing changes in lateral acceleration Pg) (59 to 62). Write the contents of register GRT2 in which the correction amount is written to register GRTI (59)
, Read the correction amount Crt corresponding to Vs, R, and g from one area (table 8) of the internal ROM and write it to the register CRT2 (61), Data Grt of table 8
are grouped using Vs as an index, and CPU1
7 specifies a group with Vs and reads out the data Crt corresponding to Rg in the specified group. For each group, the smaller the Vs assigned, the larger the dead zone a width (Table 8 shown in FIG. 10b). The horizontal width of Crt=O inside) is set large. b is a region in which the gain is increased as the lateral acceleration Rg increases and control performance is improved; C is a region in which control performance is degraded because more than the sensor is considered.

Next, the CPU 17 calculates a correction amount CGR for suppressing a change in the lateral acceleration Rg using the following formula and writes it into the register CGR (62).

CGR=Kgr3 (Kgrl ・gr2 to GRT2+
(GRT2-GRTI)) GRT2 is register CRT2
This is the content of the correction amount C read out from Table 8 this time.
It is rt.

GRTI is the content of register GRTI and is the correction amount read from table 8 last time. P (proportional) term Kgr
Kgr of 1.GRT2 1 is the coefficient of the proportional term.

Kgr of gr21GRT2-GRTI) in D (differential) term
2 is the coefficient of the differential term, and this coefficient gr2 is the vehicle speed V
This is read from an area (table 9) of the internal ROM corresponding to s. As shown in "Table 9" in FIG. 10b, the coefficient Kgr 2 is approximately the vehicle speed Vs
The higher the value, the larger the value, and the greater the weight of the differential term.

This is because the differential term is a correction term that attempts to quickly suppress changes in lateral acceleration Rg, and the higher the vehicle speed, the faster the change in lateral acceleration Rg due to turning/returning due to steering rotation. This is to quickly suppress this problem. On the other hand, when the vehicle speed v8 exceeds a certain level, turning/returning by turning the steering wheel,
If this occurs suddenly, the change in lateral acceleration Rg will be sudden and extremely large, and an excessively large differential term that quickly suppresses such a sudden change will degrade the stability of lateral acceleration suppression. Therefore, the coefficient Kgr 2 in Table 9 is
In more detail.

With respect to changes in vehicle speed Va, when vehicle speed Vs is low, it changes greatly, and when vehicle speed Vs is equal to or higher than a predetermined value, it is constant.

That is, when the vehicle speed Vs is 7% lower, the weight of the differential term changes greatly with respect to changes in vehicle speed, but when the vehicle speed Vs is high, the weight of the differential term does not change with respect to changes in vehicle speed.

The calculated CGR is a roll correction amount for the suspension five, and Kgr3 is a coefficient that is weighted for the pitch correction amount CGP described above and the roll correction amount GES described later, but when the vehicle speed v8 is low, the lateral correction amount is Since the rate of change of the acceleration Rg is low, the contribution ratio of this roll correction amount CGR is lowered in the low speed range, and the internal ROM is set to a constant value in the high speed range.
Coefficient data Kgr3 is stored in one area (table 10) corresponding to the speed Vs. The CPU 17 reads out the coefficient Kgr3 corresponding to the speed Vs, and uses it for calculating the above-mentioned CGR.

The lateral acceleration Rg changes due to a change in the steering position (rotational position) (steering angular velocity Ss), and the rate of change also depends on the vehicle speed Vs. That is, since a change in the lateral acceleration Rg also corresponds to the steering angular velocity Ss and Vs, the roll correction amount Ges required to suppress this change is written in an area (table 11) of the internal ROM of the CPU 17. C.P.
U17 checks whether the steering angle acceleration Sa is substantially zero (64), and if it is not substantially zero, the table 1
1, reads the roll correction amount Ges corresponding to the combination of Vs and Ss and writes it into the register GES (65);
If it is substantially zero (the previous steering angular velocity and the current steering angular velocity are equal: the roll correction amount Gas read last time can be used as the current roll correction amount), the update write (65) to the register GES is Not executed.

[CPU] 7 then converts the calculated pitch correction amount CGP, roll correction amount CGR, and roll correction amount DES into pressure correction amounts addressed to each suspension, and applies these pressure correction amounts to the ``vehicle height deviation calculation''. The value EHf calculated by “W” (3x)
L, EHfr, EHrL.

Et(rr (register EHf L, BHfr,
Ellr L , contents of EHrr ) and the obtained sum Ehf L I Ehfr, Ehr L , Eh
rr into registers EHf L, EHfr, EHr
Update is written to L and EHrr (66).

Ehf L = Ellf L +Kgf L ・(1/
4)・(-CGP+Kegrf'CGR+Kgef L
-GES)Fhfr =EHfr +Kgfr・(1
/4)・(-CGP-Kcgrf-CGR-Kgefr
-GES)Ehr L =E)lr L +Kgr L
・(1/4)・(CGP+Kcgrr-CGR+KH
er L −GES)Ehrr =EHrr +Kgr
r・(1/4)・(CGP-Kcgrr”CGR-Kg
err-GES) The first term on the right-hand side of the above equation is the value previously calculated by "vehicle height deviation calculation J (31), and is stored in register Elf.
L, EHfr.

This was written in EHr L and EHrr, and the second term on the right side is the value obtained by converting the pitch correction amount CGP, roll correction amount CGR, and roll correction JLGES described above into pressure correction values addressed to each suspension. .

In addition, the coefficient Kgf L I Kgfr of the second term on the right side,
Kgr L and Kgrr are Kgf L = Kf L - Kgs.

Kgfr = Kfr - Kgs.

KgrL = Kr L 0Kg5゜Kgrr = Krrゝgg, KfL, nifr, Kr L, Krr are coefficients (piping length correction coefficient)
As shown in Table 12, Kgs is a predetermined coefficient associated with the steering angular speed Ss, and Kgs is a coefficient that is predetermined in association with the steering angular speed Ss, /Rolling prediction calculation J (32
), the pressure correction value for suppressing acceleration changes (the second term on the right side of the above 4 equations: (1/4)・(−CGP+
grfrCGR+Kgef L-GES), etc.). If the steering angular velocity Ss is large, a rapid change in acceleration is expected, and it is preferable to increase the weighting of the pressure correction value for suppressing the change in acceleration. Therefore, the coefficient gs is approximately set large in proportion to the steering angular speed Ss. However, the steering angular speed Ss is below a certain level (Table 1
2, 50@/m5ec or less), the change in acceleration is extremely small, and it exceeds 50@/vasec to 400@/m5e.
Below c, the acceleration changes at a speed substantially proportional to the steering angular speed Ss. At steering angular speeds of 400°/rmsec or higher, the change in turning radius is rapid and extremely large, resulting in extremely large changes in acceleration (especially lateral acceleration). The correction amount degrades the stability of acceleration control. Therefore, the weighting coefficient Kgs corresponding to the steering angular speed Ss is 5 when Ss is 5.
Constant value below 0°/wasec, 50' 1m5
If it exceeds ec and is less than 400'/rmsec, it is set to a high value that is substantially proportional to Ss, and if it exceeds 400'1m5ec, it is set to a constant value of the value at 400'1m5ec.

Next, the CPU 17 registers the initial pressure register P F L o t
The initial pressure data (set in steps 16 to 18) written in PFR, PRLO, and PRR is executed in subroutine 6.
6, the sum of the correction pressure for vehicle height deviation adjustment and the correction pressure for acceleration suppression control (register EHf L,
EHfr, EHrL, EHrr contents) to calculate the pressure to be set for each suspension,
Register El(f L I EHfr l EHr L
Update is written to IEHrr (67).

To explain the contents of "Pressure correction J (33)" with reference to FIG. A correction value PH that compensates for the fluctuation in is read from one area (table 13H) of the internal ROM, and corresponds to the detected pressure DPL (the contents of the register DPL) of the pressure sensor 13rt.

The correction values PLf (front wheel side correction value) and PLr (rear wheel side correction value) that compensate for fluctuations in the output pressure of the pressure control valve due to return pressure fluctuations are read from an area of the internal ROM (table 13L), and the pressure control valve Pressure correction values PDf=PH−PLf and PDr=PH− to compensate for fluctuations in pressure control valve output pressure due to fluctuations in line pressure and return pressure applied to
Calculate PLr (68.69).The correction value corresponding to the return pressure is divided into the front wheel side and the rear wheel side because the front wheel side is closer to the reservoir and the rear wheel side is farther from the reservoir, and is used for low pressure detection. Since the pressure sensor 13rt detects the return pressure on the rear wheel side, the return pressure is relatively large on the rear wheel side and the front wheel side, so this is to reduce the error caused by this.

Table 13L stores two groups of correction value data to be assigned to the rear wheel side and correction value data group to be assigned to the front wheel side, the latter data for the front wheel suspension and the former data for the rear wheel suspension. From the group, the supplementary market value corresponding to the pressure of the pressure sensor 13rt at that time is read out.

Note that if the pressure sensors 13+* and 13rt fail, the corresponding correction values are maintained at predetermined values.

After calculating the correction values PDf and PDr, the CPU 17 stores these correction values in the register EHf L t EHfr
tEtlr L e In addition to the contents of El+rr, registers ElfL, EHfr, El(r L , BH
An update is written to rr (70).

Referring to FIG. 10d, the contents of the pressure/current conversion J (34) will be explained.
, EHfr, EHr L and EHrr data EHfw.

Pressure control valve 80f L e 80fr for generating the pressures shown by EHfr, EHr L and EHrr
t 80r Current value I to be passed through L and 80rr
hf L t Ihfr y Ihr L and Ihr
r from the pressure/current conversion table 1 and output the current output registers Il+f L and IHfr, respectively.

IHr L and I) Write to lrr (34).

The details of warp correction (35) will be explained with reference to FIG. 10e. This warp correction (35) calculates an appropriate target warp DWT from the lateral acceleration Rg and the steering angular velocity Ss.
3), and the above-mentioned register IHf L I IHfr
, IHr L t Calculate the warp that appears when outputting the contents of IHrr, and calculate the target warp DWT of this
74 to 76), and the current correction value dIf required to make this error warp amount zero.
L dIfr t dIr L T dIrr is calculated (77), and these current correction values are stored in the register IH.
It is added to the contents of f L , IHfr, IHr L and IHrr, and the sum is updated and written to these registers (78).

A warp target value Idr corresponding to the lateral acceleration Rg is written in one area (table 14) of the internal ROM of the CPU 17, and a warp target value Ids corresponding to the steering angular velocity Ss is written in the table 15. , Table 16 shows the registers IHf L , II to be output from now on.
The warp correction amount Idrs corresponding to the vehicle body longitudinal inclination and lateral acceleration Rg (stealing slope) defined by the values of (fr, IHr L, IHrr) is written. Note that the longitudinal inclination is expressed as K= l (Ihf L +Ihfr)/(Ihr L
+Ihrr)! Data groups corresponding to this are written in the table 16, and each data in each data group is associated with the lateral acceleration Rg.

The CPU 17 reads the warp target value Idr corresponding to the lateral acceleration Rg and reads the warp target value Idr corresponding to the steering angular velocity Ss from the table 14.

And register If (f L # IHfr, IHr
Warp correction amount I corresponding to the vehicle body longitudinal inclination and lateral acceleration Rg (stealing inclination) defined by the value of L t Hlrr
drs from table 16 and warp target value D
WT is calculated as follows (73).

DWT=Kdv1 ・Idr+Kdw2 ・Ids+K
dw3 ・IDrsCPU17 next registers IHf
L, IHfr, IHr L.

Contents of I+1rr Ihf L , Ihfr, Ihr L
, Ihrr (Ihf L Ihfr) - (Ihr L Ih
rr) and checks whether it is within the allowable range (dead zone) (74). If it is outside the allowable range, the calculated warp (Ihf L
Ihfr) - (Ihr L Ihrr) is subtracted and the value is written to the warp error correction amount register DWT (75
), and when it is within the allowable range, the contents of register DWT (D
WT) is not changed. And warp error correction amount DW
Multiply T (contents of register DWT) by weighting coefficient Kdw4 and update and write the product to register DWT (76)
, this warp error correction amount DWT is converted into each suspension pressure correction amount (more precisely, the pressure control valve energizing current correction value corresponding to the pressure correction layer) (77), and the corresponding correction is sent to the current output register IHf. L, IHfr, IH
r Add to the contents of L and IHrr (78).

These current output registers IHf L , I) Ifr
, IHr L and IHr r data are determined by the "output J (36) subroutine, pressure control valves 80fc, +
Addressed to 80fr, 80rr and 80rr, CPU18
Transfer to.

Since the processes of status reading (20) to output (36) explained above are performed in the STI cycle, the CPU 18 has
The CPU 17 instructs the transfer of detection data in the STI period (by the status reading 20), and the CPU 17 instructs the pressure control valve 80f L in the ST1 period.

80fr, 80r L, 80rr and bypass valve 1
The energizing current value data addressed to 20 is given. CPU18
are the sent pressure control valves 80f L, 80fr,
The energizing current value data of 80r L and 80rr is stored in the register RIHf L + RIHfr r RI) Ir L
Write an update to tRItlrr. Therefore, the CPU
18 registers RIHf L , RIt(fr, RIH
r L, RIHrr has a constant pressure control valve 80f L
, 80fr, 80r L, and 80rr are stored with data indicating the current values to be passed through them, and are updated at the STI cycle.

The control operation of the CPU 18 will be explained with reference to FIG. 12a. The CPU 18 powers itself on (81)
Then, after initialization (82), status reading (83), and abnormality check (84, 85), if there is no abnormality, the r communication interrupt is permitted (8G), and a ready message is sent to the CPU 17 (87). .

Then, timer ST2 is started (88), and vehicle height sensors 15f L , 15fr, 15r L , 15rr,
Pressure sensor 13fL.

13fr, 13r L, 13rr, 13rm, 13
rt, and acceleration sensors 16r, 16p, and
Pressure control valve 80f L, 80fr.

80r L , 80rr and the current values of the bypass valve 120 are determined by the A/D converters 291 to 29. Convert it to digital and read it (89), then read the vehicle height sensor 15fL,
Detection data df of 15fr, 15r L, 15rr
L, dfr, dr L, drr are weighted averaged (smoothed) with the average value (loaded average value) of the values read several times so far to obtain vehicle height data (average value) Df L, Dfr.

Obtain Dr L and Drr, registers DFL, DFR,
Update is written to DRL and DRR, and the pressure sensor 13 is
f L , 1.3fr, ], 3r L .

Detection data of 13rr Pf L #Pfr#Pr L
, Prr is weighted averaged (smoothed) with the average value (loaded average value) of the values read several times so far to obtain vehicle height data (average value) PfLtPfrrPr L , Prr, and the registers PFL, PFR, PRL , update write to PRR (90), other pressure sensors 13rm, 13rt.

Data on the current values of the acceleration sensors 16r and 16P, the pressure control valve, and the bypass valve are similarly processed and updated and written in the register.

The CPU 18 next selects the pressure sensors 13f L and 13fr.
.

13r L, 13rr pressure detection data (read value)
PfL.

pfr, pr L Rate of change of tPrr dpf L, d
Calculate pfr, dpr L and dprr (91);
These rates of change are obtained by subtracting the previous read value from the current read value. The current read value is written to the register replacing the previous read value.

The CPU 1.8 then calculates the rate of change dPf L , dpfr,
dprL.

energizing current instruction value of the pressure control valve corresponding to each of dprr (output pressure correction value: second correction amount) SIf L, 5I
fr.

SIr L and 5Irr are read from one area (table 17) of the internal ROM, and these are stored in register RIHf.
L, RIHfr.

In addition to each of the data of RII(r L and RIHrr, the obtained sum is output to the output registers 0IHf
r, 0IHr L, 0IHrr with update number (92
), and gives the data of these output registers to the duty controller 32 (93).

Note that the second energizing current correction value (second correction amount: SIf L).

5Ifr, SIr L , 5Irr) are values roughly inversely proportional to the rate of change, as shown in Table 17 of FIG. 2a.

It is a negative value when the rate of change is positive (pressure increase).

It is a positive value when the rate of change is negative (pressure drop).

The CPU 18 next operates the pressure control valves 80f L and 80fr.
.

80r L , 80rr and the current value data of the bypass valve 120 are given to the duty controller 32 (
94), wait for the timer ST2 to time out, that is, wait for the elapsed time from the start of timer St2 in step 88 to reach the second set period ST2 (95), return to step 88, and start timer ST2 again. . From then on.

The processes of steps 88 to 95 are repeated in the ST2 period, so that the pressure sensors 13f L , 13fr, 13
Reading the detected pressure of r L , 13rr (89), calculating the rate of change of the detected pressure (&1).

Calculation of correction value (second correction amount) corresponding to rate of change (91), C
Correction of the second correction amount for the pressure (current value) instructed by PUl7 (92) and output of the corrected pressure (current value) (93) are performed in the second setting cycle ST2. As mentioned above, registers RIHf L , RIHfr, RI
The data of Hr L and RIHrr (pressure instruction value from CPU 17: energization current instruction value) is the 1st+12th constant period sT1
Therefore, the pressure instruction value (energization current instruction value) including the first correction amount for correcting the deviation of the vehicle height (heap) detected by the vehicle height sensor from the reference vehicle height is updated at the STI cycle. On the other hand, the second correction amount corresponding to the change rate of the suspension pressure is updated in the ST2 cycle and added as a correction to the pressure instruction value including the first correction amount.

FIG. 12b shows the communication interrupt processing operation of the CPU 18 when the CPU 17 sends a data transmission signal (communication interrupt signal) to the CPU 18. When the data arrives, the CPU 18 receives the data sent by the CPU 17 (101).

Based on the identification bit in the received data, the sent data is
Determine whether it is the energizing current value data of the pressure control valve and the bypass valve (output instruction data: 36 in Figure 9b) or a data transfer request (20 in Figure 9a) (102);
If the energizing current value data is the pressure control valve 80f L z 80fr, 80r L e 80 in the received data.
Current value data IHf L , IHfr, addressed to rr
IHr L, IHrr to register R111f L,
Updates are written to RIHfr, RIHr L, and RIHrr, and the energizing current value data addressed to the bypass valve 120 is given to the duty controller 32 (103). When it is a data transfer request, registers DFL, DFR, and D
R.L.

The vehicle height data, pressure data, and communication data written in RR, PFL, PFR, PRL, PRR, etc. Transfer the m flow value (detected value) data to the CPU 17 (104, 105)
.

〔Effect of the invention〕

As described above, according to the present invention, the second correction amount calculation means (18
) detects the direction of change in the suspension pressure (pfr) at a predetermined period or time constant ST2 shorter than the STI, and when the suspension pressure (pfr) is in the increasing direction in response to the direction of change, the suspension pressure is lowered. Second correction ff1 (SIfr) in the direction of increasing when it is in the decreasing direction
The target pressure setting means (18, 32, 33) calculates the second
Since the pressure control means (80fr) is electrically energized to apply a pressure correction corresponding to the correction amount to the suspension pressure, the suspension pressure starts to rise, for example, and this rise causes the vehicle height to rise and respond accordingly. By the time this increase is suppressed by the feedback of the first correction amount, the suspension pressure is suppressed by the feedback of the second correction amount and the rise in vehicle height is suppressed, thereby suppressing the first correction amount. . That is, the feedback with a shorter cycle or time constant ST2 acts faster than the feedback of the first correction amount (correction based on the detected value of the vehicle height detector: lt) with a relatively long cycle or time constant srt, and the suspension The pressure correction amount (first correction ji) is suppressed. this,
Suppression of the first correction amount acts only when the suspension pressure increases or decreases, so it acts at or immediately before the vehicle height changes.

Therefore, even when setting a relatively high control gain that is likely to cause the above-mentioned high and low vibrations (oscillation or hunting), such high

Increased suspension pressure resulting in low vibration.

At the time of decrease, the correction amount (first correction amount) is automatically suppressed, so that such high and low vibrations are less likely to occur.

That is, according to the present invention, a relatively high control gain can be set to realize stable and highly responsive pressure control.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a suspension pressure supply system according to an embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view of the suspension 100fL shown in FIG. FIG. 3 is an enlarged longitudinal sectional view of the pressure control valve 80fL shown in FIG. 1. FIG. 4 is an enlarged longitudinal sectional view of the cut valve 70fL shown in FIG. 1. FIG. 5 is an enlarged longitudinal sectional view of the relief valve 60fL shown in FIG. 1. FIG. 6 is an enlarged longitudinal sectional view of the main check valve 50 shown in FIG. FIG. 7 is an enlarged longitudinal sectional view of the bypass valve 120 shown in FIG. 1. FIG. 8 is a block diagram showing the configuration of an electric control system that controls suspension pressure in response to detected values from a vehicle height sensor, a pressure sensor, etc. of the suspension pressure supply system shown in FIG. 1. 9a and 9b are flowcharts showing the control operation of the microprocessor 17 shown in FIG. 8. 10a, 10b, 10c, 10d, and 1ee are flowcharts showing the contents of the subroutine shown in FIG. 9b. FIG. 11a and FIG. 11b show the internal R of the CPU 17,
It is a graph showing the contents of data written in OM. FIGS. 12a and 12b are a flowchart 1- having the microprocessor 180 control operation shown in FIG. 1: Pump 2: Reservoir 3: High pressure boat 4: Accumulator 6: Front wheel high pressure supply Iv
7: Accumulator 8: High pressure supply pipe 9: Rear shaft high pressure supply v 10: Accumulator 11: Reservoir return pipe 12 Nidrain return pipe 13f L
, 13fr, 13r L, 13rr, 13r
m, 13rt: Pressure sensor 14f L, 14f
r, 14r L, 14rr: Drain of atmospheric release 15f L, 15fr, 15r L, 15
rr: Vehicle height sensor 16p: Front/rear acceleration sensor
16r: Lateral acceleration sensor 17: Microprocessor 18: Microprocessor Ig: Battery 20: Ignition switch 21: Constant voltage power supply circuit 22: Relay 23 Backup power supply circuit 24; Brake lamp
25: Vehicle speed synchronous pulse generator 2G two-rotary encoder 27: Absolute encoder 28: Hot water level detection switch 291 to 293: A/D
Converters 301 to 303: (:i processing circuit 3
1: Low-pass filter 32: Duty controller
33: Coil driver 34: Input/output circuit
fO: Main engine pzo 51: Valve base 52: Input boat 53: Output boat 54: Valve seat 55: Flow port 56: Compression coil spring 57: Ball valve parallel fr, 3 concave J=tμ leek, 60r7: T)
I Munisbe Fire 61: Valve base 62: Input port
63: Low pressure port 64: First guide G5: Filter 66: Valve body 67: Second guide 6
8: Valve body 69: Compression coil spring 7I
: Valve base 72 Line pressure boat 73: Pressure regulation input port door 4: Haiyu port 75: Output port
76: First guide 77: Guide 78 Niss spool 79: Compression coil spring Setha J residence 7 Cod trowel valve 81 Nisleeve 82 Ni line pressure port 83: Groove 84: Output boat 85: Low pressure boat 86: Groove 87: High pressure boat 88: Target pressure space 88f niorifice 89: Low pressure boat 90 varnish spool
91: Groove 92: Compression coil spring
93 Mi valve body 94: Channel 95: Needle valve
96: Fixed core 97: Plunger 98a: Yoke 98b: End plate 98c: Low pressure boat 99: Four for electric coil
1jr, -kiran w, 101rr, river ↓ shock absorber 102fr, 102f L, 102rr,
102r L: Piston rod] 03: Piston
104: Inner cylinder 105: Upper chamber 106: Lower chamber 107: Side port 108: Vertical through hole 109: Valve damping valve system rX1110: Between lower chambers 11: Piston 112: Lower chamber 113: Upper chamber 11
4: Outer cylinder 120: Bypass valve 1
21: Input boat 122: Low pressure boat 122a: Low pressure boat)-122b: Channel 123: First guide 124a
: Valve body 124b : Compression coil spring
125: Needle valve 129: Electric coil patent applicant Toyota Motor Corporation

Claims (1)

[Scope of Claims] A pressure source for supplying pressure fluid to a suspension that expands and contracts in accordance with the supplied pressure; Pressure control means that is located between the pressure source and the suspension and sets the suspension pressure to a target pressure; The suspension height detection means for detecting the height of the vehicle body supported by; instruction means for generating height instruction information specifying a reference height; height detection means for detecting the reference height indicated by the height instruction information; first correction amount calculation means for calculating a first correction amount corresponding to the difference in height at a predetermined period or time constant ST1; pressure detection means for detecting suspension pressure; said ST1
The direction of change in the detected suspension pressure is detected at a shorter predetermined period or time constant ST2, and corresponding to the direction of change, the suspension pressure is lowered when the suspension pressure is increasing, and is increased when it is lowered. a second correction amount calculation means for calculating a second correction amount; and a target pressure for electrically energizing the pressure control means so as to add a pressure correction corresponding to the first correction amount and the second correction amount to the suspension pressure. A suspension pressure control device comprising: setting means;