JPS6164509A - Electronically controlled suspension device - Google Patents

Abstract

PURPOSE:To obtain at all times a proper control variable for attitude control by keeping the spring reaction force of a suspension unit when the front and rear levels of the body reaches desired levels corresponding to the standard attitude. CONSTITUTION:Level sensor means 31 includes a front level sensor 31F mounted on a lower arm 32 of a front right suspension of an automobile and adapted for detecting the front level of the automobile and a rear level sensor 31R mounted on a lateral rod 33 of a rear left suspension of the automobile and adapted for detecting the rear level of the automobile, both sensors 31F, 31R transmitting detecting signals to a control unit 34 serving as a level control. Air is exhausted through an exhaust direction change-over valve 28 and a residual pressure valve 29 to a reserve tank 15b under a lower pressure so as to control the front and rear levels of the body toward desired levels corresponding to the standard attitude of the body.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention is directed to reducing the sinking (nose dive) of the front part of the car body and the drop (dive) of the rear part of the car body, which occur due to longitudinal acceleration applied to the car body, for example. The present invention relates to an electronically controlled suspension device that suppresses suspension.

[Technical background of the invention and its problems]

Generally, when a forward acceleration is applied to the vehicle body when starting or accelerating a vehicle, a phenomenon occurs in which the height of the rear portion of the vehicle body decreases and the front portion of the vehicle lifts up. Conversely, if rearward acceleration is applied to the vehicle body when braking or stopping the vehicle, a nose dive phenomenon occurs in which the front of the vehicle sinks and the height of the rear of the vehicle rises. Therefore, an electronically controlled suspension device that electronically suppresses such a null-auto phenomenon and a nose-dive phenomenon has been considered. In other words, this electronically controlled suspension system controls the spring reaction of the suspension unit in the direction in which the vehicle body sinks when it predicts that a change in attitude will occur in the vehicle body based on the longitudinal acceleration applied to the vehicle body or the time derivative of that acceleration. This increases the force and reduces the spring reaction force of the suspension unit in the direction of floating, absorbing the above change in attitude and keeping the vehicle level. Here, the upper 1J and lower `Ik of the spring reaction forces are set in advance as a predetermined control I.

Thereafter, when the factor (for example, acceleration) that causes the attitude change as described above is reduced, the control of the spring reaction force, which is opposite to the above, is carried out for a predetermined period of time, and the attitude control state is released.

However, in an electronically controlled suspension system that always increases or decreases the suspension spring reaction force by a predetermined control amount, for example, if the predetermined control l is set in accordance with the attitude control performed during normal acceleration and braking, Also, large changes in attitude that occur during sudden braking cannot be sufficiently suppressed, resulting in problems such as force.

Furthermore, since the amount of change in the attitude of the vehicle body during acceleration and deceleration varies greatly depending on the increase or decrease of occupants and cargo, if the attitude control is always performed by only a predetermined amount as described above, for example, if there is only one occupant, the inertia of the vehicle body will increase. If it is small, the amount of attitude change b is relatively small, so there is a risk that attitude control will be performed more than necessary, resulting in 1. On the other hand, if there are five occupants and the inertia of the vehicle body is very large, on the other hand, the amount of attitude change will be large, and there is a risk that attitude control will not be carried out effectively.

[Purpose of the invention]

This invention was complicated by the problems mentioned above.
For example, as the number of passengers increases or decreases, the inertia of the vehicle body changes and the attitude changes.
It is an object of the present invention to provide an electronically controlled sanupension device that can always perform attitude control with an appropriate control amount even when the values differ greatly.

[Summary of the invention]

In other words, the electronically controlled suspension device according to the present invention has a suspension unit having a spring reaction force adjustment mechanism for each wheel, and when an acceleration in the longitudinal direction of the vehicle body of more than a predetermined value is detected by the acceleration & sensor, each of the above-mentioned suspensions Units) (2) Adjust the spring reaction force to start attitude control in the direction of countering changes in the attitude of the vehicle body, and when the vehicle height of the front and rear of the vehicle body reaches the target vehicle height corresponding to the standard attitude of the vehicle body. The spring reaction force of each suspension unit is maintained.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronically controlled suspension device according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, near suspension unit Fs1. FS2. R8J
, R82 have almost the same structure, so hereafter, the Air Sanupension Units In- will be replaced by the symbol S, unless the front and rear types are specifically explained.
The explanation will be made using the following figure, and only the parts necessary for vehicle height control will be illustrated and explained.

In other words, the air suspension unit S is a built-in shock absorber I, and the shock absorber 1 is slidably inserted into a cylinder attached to the front wheel or ridge wheel side. The cylinder moves up and down with respect to the piston rod 2 in response to the up and down movement of the wheel, which makes it possible to effectively absorb shock and change the damping force in accordance with the stroke of the wheel. be.

At the top of this shock absorber 1, a main air spring chamber 3 which also serves as a vehicle height adjustment fluid chamber is arranged coaxially with the piston rod 2, and a part of this fresh air spring chamber is covered with a bellows 4. Because of this, the piston rod 2 can be moved up and down by supplying and discharging air to the main air splash chamber 3 through the passage 2a provided in the piston rod 2.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 5a facing upward, and the outer wall of the main air spring chamber 3 is provided with a spring receiver 5b facing downward.
A coil spring 6 is loaded between the spring receivers 5B and 5b.

Thus, 11 is a compressor. This compressor 11 compresses the atmospheric air sent from the air cleaner 12 and supplies it to the dryer 13, and the compressed air dried by silica glue etc. of the dryer 13 is sent to the reserve tank 15 via the check valve 14'f. It is stored in the high pressure side reserve tank 15a inside. This reserve tank 15 is provided with a low pressure side reserve tank 15b. A compressor 16 driven by a compressor relay 17 is connected between the reserve tanks 15a and 15b.
is provided. ′! Furthermore, a pressure switch 18 is provided which is turned on when the pressure in the low pressure side reserve tank 15b becomes equal to or higher than atmospheric pressure. When the pressure switch 18 is turned on, the compressor relay 17 is driven. As a result, the reserve tank 1sblti is always kept below atmospheric pressure.

The route through which compressed air is supplied from the high-pressure side reserve tank 15a to the suspension unit S is indicated by a solid arrow. That is, the compressed air from the reserve tank 15a is supplied to the air supply solenoid valve 19, which will be described later.
Air supply flow rate control valve similar to a directional valve 20. It is sent to the front Furukawa suspension unit FS2 and the front right suspension unit FS1 via the check valve 21, the front Furukawa solenoid valve 22, and the solenoid pulp 23 for the front right. Similarly, the compressed air from the reserve tank 15a is supplied to an air supply solenoid valve 19, an air supply flow rate control valve 20 consisting of a three-way valve, which will be described later. Check pulp24. Solenoid pulp for rear clothing25. Suspension unit for rear clothing via solenoid pulp 26 for rear right) r? , S2
, is sent to the rear right suspension unit R8z. On the other hand, what is the exhaust route from the suspension unit t-S? ; Indicate with a line arrow. Exhaust from the FSI and FSI is sent to the low pressure side reserve tank 15b via the solenoid pulp 22, 23, exhaust flow rate control valve 27, exhaust direction switching valve 28, and residual pressure valve 29. Furthermore, suspension unit FS1. The exhaust from FSz is solenoid pulp 22.
23, exhaust flow rate control valve 27, exhaust direction switching valve 28. Dryer 13° exhaust solenoid valve 30. It is released to the atmosphere via the air cleaner 12. Also, suspension units R8J, R8,? The exhaust gas from the solenoid pulp 25° 26 is sent to the low pressure side reserve tank 16b via the exhaust flow control valve 27, the exhaust direction switching valve 28, and the residual pressure valve 29. However, if the pressure in the reserve tank 15b is smaller than the pressure in the main air spring chamber 3, the residual pressure valve 29 is opened and the reserve tank 1 is opened.
When the pressure at 5b is greater than the pressure at main air spring house 3, the residual pressure valve 29 is closed. Sarani, exhaust from suspension unit R8I, R82 is solenoid pulp 25
, 26, exhaust flow i control pulp 27, exhaust direction switching valve 28, dryer 13. It is released to the atmosphere via the exhaust solenoid valve 30 and the air cleaner 12.

In addition, this vehicle height sensor 311ri is a 31-piece vehicle height sensor.
A front vehicle height sensor 31F is attached to the lower arm 32 of the front right suspension of the automobile to detect the front vehicle height of the automobile, and a front vehicle height sensor 31F is attached to the lateral rod 33 of the rear left suspension of the automobile to detect the rear vehicle height of the automatic east vehicle. It is configured with a rear vehicle height sensor 31R for detecting,
Detection signals are supplied from these vehicle height sensors 31F and 31R to a control unit 34 as a vehicle height adjustment control section.
,ru.

Each sensor 31F in the vehicle height sensor 3.

31R is designed to detect distance contributions from the normal vehicle height level, low vehicle height level, and high vehicle height level.

Furthermore, a vehicle speed sensor 35 is built into the speedometer, and the sensor 35 is designed to detect the vehicle speed and supply the detected signal to the control unit 34.

Further, an acceleration sensor 36 is provided as a vehicle body posture sensor for detecting changes in the posture of the vehicle body. This acceleration sensor 36 is designed to detect changes in the pitch, roll, and yaw of the car body on the car's springs. A sensor output voltage VG proportional to the magnitude of acceleration G is obtained. This acceleration detection voltage (G) is supplied to the control unit 34.

Further, 37 is an indicator for displaying oil pressure, and the display of this indicator 37 is controlled by the control unit 34. Further, a steering sensor detects the rotational speed of the 38-wheel steering wheel 39, that is, the sweeping speed, and its detection signal is sent to the control unit 34.

Specifically, 40 is an accelerator opening sensor (not shown) that detects the depression angle of the accelerator pedal of the engine. The detection signal is sent to the control unit 34. 4 is a compressor relay for driving the compressor 11, and this compressor relay 41 is controlled by a control signal from the control unit 34. Furthermore, there is a pressure switch that turns on when the pressure in the 42-liter reserve tank 15a falls below a predetermined value V, and its output signal is output to the control unit 34. Then, the compressor relay 41 (under the control of the pressure switch 341 and the control unit 34) is driven. As a result, the compressor 11 is driven to feed compressed air into the reserve tank 15a, and the pressure inside the reserve tank 15a is raised to a predetermined value v. It is also a gear position sensor that detects the shift position of a 43-speed transmission (not shown), and its detection signal is supplied to the control unit 34. So, the above solenoid pulp 19.22,23
, 25, 26.30 and the pulp 20, 27.28 are controlled by control signals from the control unit 34.

In addition, the solenoid pulp 22, 23.25° 26 and the pulp 2θ, 27.28 are heated from the three-way valve, and the two
The two states are shown in Figure 2. Figure 2 (4) F
This shows a state in which the i3-way valve is driven, and in this state compressed air moves along the path indicated by arrow A. On the other hand, FIG. 2(B) shows a state in which the three-way valve is activated, and in this state compressed air moves along the path indicated by arrow B. Still, the solenoid pulp 19.30 is more potish than the two-way valve, and its two states are shown in Figure 3. FIG. 3 (5) shows a state in which the solenoid pulp is driven, and in this state compressed air moves in the direction of arrow C. On the other hand, if the solenoid pulp is not driven, the third
As shown in FIG. 3) 11 In this case, there is no flow of compressed air.

Next, in the electronically controlled suspension system configured as described above, the attitude control operation for suppressing the nose dive and swivel that occur in the vehicle body will be described with reference to the flowchart shown in FIG.

First, in step SJ, the acceleration voltage VG proportional to the detected acceleration G in the longitudinal direction of the vehicle body from the acceleration sensor 36 is read into the control unit 34, and its time differential value VG is calculated. Next, the process proceeds to step S2, where the acceleration voltage VG read in step S1 and its value VG are added in the control unit (94).
ΣVG:VG+α+G). However, α is a constant and can be adjusted as appropriate. Then, in step 53JK, the vehicle height data of the front part of the vehicle body detected by the front vehicle height sensor 31F and the rear vehicle height sensor 31R and the vehicle height of the rear part (7') are updated every tf6msec. 160 pieces of vehicle height data, that is, 0.96 seconds (
tl) The average value of the vehicle height data read during the above period is calculated at step S4 every 6 msec.

Next, the process proceeds to step S5, where it is determined whether or not the value of the acceleration data (JVa) calculated in step S2 is less than the first predetermined value B. When the data (ΣVc) of the acceleration G acting in the ridge direction reaches the first predetermined value or more, and it is determined that a factor causing a change in the attitude of the vehicle body such as a nose dive or a nose dive has occurred, the process proceeds to step S6, and the attitude is changed. It is determined whether the control solenoid valve is in a holding operation. Here, during the holding operation, the air supply solenoid valve 19, the front solenoid valves 7' and 22, 23, and the rear solenoid valves 25 and 26 are all turned off, and the front suspension unit) FSl, FS2 main air splash chamber 3 and rear suspension units R81, R82
The main air springs 3 and 3 are each independently closed and held, so if "NO" is selected in this step S6.
If it is determined that this is the case, the process advances to step S7. This step S7
Now, the acceleration amount data (ΣVc) in the longitudinal direction of the vehicle body determined to be equal to or greater than the first predetermined value B in step S5 above.
It is further determined whether or not C is less than a second predetermined value C.

Here, the relationship between the first predetermined value B and the second predetermined value C will be shown below.

IBI < ICI If "YES" is determined in this step S7, and it is determined that the value of the above acceleration data (ΣVo) is relatively small and the attitude change occurring in the vehicle body is small, the value is slowly increased to 9 correspondingly. In order to execute posture side #, the process proceeds to step S8, where the supply air flow rate control valve 20 and the exhaust air flow rate control valve 27 are turned on under the control of the control unit 34, and the small diameter supply air flow path and the exhaust air flow path M are set, respectively. Ru. At the same time, in step S9, the control unit 34 starts storing the ON time (TMI) of each of the flow rate control valves 20.27. On the other hand, if "NO" is determined in step S7, that is, the acceleration data (
If it is determined that the value of ΣVc) is large and the amount of attitude change occurring in the vehicle body is large, the control unit 34 proceeds to step SJ□ to execute quick attitude control, and the control unit 34 adjusts the intake air flow rate. It is confirmed that the control valve 20 and the exhaust flow control valve 27 are turned off, and large-diameter air supply flow paths and exhaust flow paths are set, respectively.

Then, the process proceeds to step 811, where it is determined whether or not each attitude control valve is in the ON operation, that is, whether or not it is in the attitude control action. If the determination in step 811 is "NO", the process proceeds to step 812, where each attitude control valve is turned on under the control of the control unit 34, and at the same time, in step 813, t2 (for example, 0.1) see
A timer is set. Here, for example, if the acceleration data (ΣVc) of the acceleration G currently acting on the vehicle body is the backward acceleration during braking or stopping, the vehicle body is likely to undergo a forward attitude change (nose dive). Therefore, in order to perform attitude control in a direction countering this, the air supply solenoid valve 19 and the rear side solenoid valves 25 and 26 are respectively turned on in step S12. As a result, the front side pension unit)F'S7. When the main air spring of FSz is 3, the compressed air from the high-pressure side reserve tank 15 & is passed through the air supply solenoid valve 19 and the small or large diameter air supply flow path set in step S8 or S10 above, and the air supply flow rate. Control valve 201 begins to be fed via solenoid pulp 22.23. Also, both this and the rear side suspension unit) RS J.

The compressed air in the air spring chamber 3 of R82 is transferred to the solenoid valve 25, 26, the exhaust flow rate control pulp 27, and the exhaust flow path with a diameter as large as the small diameter Mt set in step 88 or 5J17, exhaust direction 9. replacement valve 28,
It begins to be exhausted to the low pressure side reserve tank J5b via the residual pressure valve 29. As a result, posture control is started in which the vehicle height on the front side is tilted upward by 9 degrees, and the vehicle height on the rear side is tilted downward by 9 degrees, and the off-shore height at the front and rear of the vehicle body is adjusted to the standard posture of the vehicle body. The vehicle height is controlled in the direction of the corresponding target vehicle height ()l'.

On the other hand, conversely to this nose type control, for example, acceleration dust data (ΣVc
) However, in the case of forward acceleration such as when starting or accelerating, the vehicle body tends to undergo a rearward attitude change (Nuquote), so in order to perform attitude control in the direction to counter this, the above steps are necessary. In S12, the air supply solenoid pulp 19 and the front side solenoid pulp 22.2
3 are respectively turned on. In addition to this, the rear side Nupencil Unit) R8J.

The main air chamber 3 of R82 is supplied with compressed air from the high pressure side reserve tank 15a through the air supply solenoid pulp 19 and the small or large diameter air supply flow path set in step S8 or f310 above. Flow rate control pulp 20
．． Begins to be fed via solenoid pulp 25.26.

Also, along with this, the front side Nu Pension Unit) F
The compressed air in the main air splash chamber 3 of SJ, FS2 is supplied to the solenoid pulp 2; Exhaust direction switching pulp 28
, the gas begins to be exhausted to the low pressure side reserve tank 15b via the residual pressure valve 29. As a result, attitude control is started to move the rear vehicle height in the upward direction and the front vehicle height in the downward direction. (H) direction.

In this way, when the attitude control process is started through steps 812 and 813, at step 814, the control unit 34 starts storing the ON time (TM) of each attitude control pulp. On the other hand, even if it is determined in step 811 that the answer is "YES", that is, each pulp is already in the ON operation due to attitude control, the process proceeds to step 814. In this case, the ON time (TM) of each attitude control pulp is also stored in memory. After the memory processing in step 814, the process proceeds to step 815, where it is determined whether t2 sec has elapsed since the timer was set in step 813 above.

If the determination is "NO" here, the process returns to step S1, and if the determination is "YES", the process proceeds to step S816. In this step S16, for example, 6 m BeC! It is determined whether the vehicle height average value (x) calculated at each time has reached the target vehicle height (H).
゜The loop processing of S14 to S16 is repeatedly executed. As a result, the vehicle height of the front and rear portions of the vehicle body changes to become closer to the target vehicle height (H)K corresponding to the reference posture of the vehicle body.

On the other hand, in this step 816, [YESJ, the vehicle height average value (ma) constantly calculated in step S4]
When the vehicle height reaches the target vehicle height (CH) and the attitude control is performed to the point where the nose dive or the nodule is suppressed and the vehicle body is substantially horizontally pointed, the process proceeds to step 817, and the process moves to an attitude control holding operation. In this step 817, the air supply solenoid pulp 19, front side solenoid pulps j12, 23, and rear side solenoid pulps 25, 26, which are turned on during the attitude control, are all turned off, and the main air of the front side suspension units FS7 and FS2 is turned off. Spring chamber 3 and rear side 7 pencil checking unit R8I. R82 main air splash chamber 3
The vehicle heights of the front and rear portions of the vehicle body are thereby maintained at the target vehicle height (H), and the process returns to step S. When proceeding to step S6 during such posture control pulp holding operation, “Y
ES", and the process proceeds to step S I B. In step S18, it is determined whether or not the value of the acceleration data (Σyc) that is constantly read and added in step S2 has changed in the direction of increasing further, for example, due to stronger braking during braking, or It is determined whether or not a stronger acceleration was performed during the acceleration. If the determination is YESJ, the attitude control processing from step S7 onwards is executed again. It's the neck, this step 818
If the determination is "NO" in step S1, the process returns to step S1.

After this, the acceleration data of the acceleration G that was acting on the vehicle body (
When ΣVa) completely falls to the first WT constant value B$, it is determined as YESJ in step S5, and the process proceeds to step S19. In this step S)9, it is determined whether or not the attitude control solenoid valve is in a holding operation, in the same manner as the determination operation in the above step S6, and in this step 819, the control in the above step 817 is currently being held. Therefore, the determination is "YES" and step 820
Proceed to. In this step S20, the above-mentioned step S14
Attitude return control is executed in accordance with the ON time (TM) of each attitude control valve stored in advance. here,
If the intake air flow control valve 20 and the exhaust flow control valve 27 are turned on in step S8, the ON time (TM) stored in advance in step S9 is
Posture return control is executed depending on the situation.

That is, for example, in step S5 above, 1'-Yg
The acceleration G that was acting on the vehicle body until it was determined to be SJ was
This is the rearward acceleration when braking or stopping, etc. If attitude control has been performed to suppress the nose dive of the car body, as the above-mentioned rearward acceleration decreases, the car body will be forced to tilt backwards due to attitude control. trying to occur. Therefore, in step S20, the air supply solenoid valve 19 and the front solenoid valve 22.
23 are turned on corresponding to the above-mentioned memory time (TM), and if the small-diameter air supply flow path and exhaust flow path M have been set in the above step S8, the above-mentioned memory time (TM) is turned on corresponding to the above-mentioned memory time (TM). and each flow control valve 20°27
is also turned on. As a result, the compressed air in the front suspension units FS J, FS2 (D main air spring chamber 3 Through the valve 28 and the residual pressure valve 29, the air is exhausted to the low pressure side reserve tank 15b by the amount of air supplied during the nose dive suppression, plus the time t, b (TM).
Along with this, the rear side
8,? Compressed air from the high-pressure side reserve tank 15a is supplied to the main air spring chamber 3 of
0, solenoid pulp 25 and 26 are supplied by the amount exhausted during the nose dive suppression, that is, the amount of time (TM). As a result, the attitude of the vehicle body returns to a steady state without being affected by the rearward thrust, and the attitude control by nose dive is released.

On the other hand, contrary to such posture return control from nose dive, the acceleration G that is acting on the vehicle body until it is determined as [YESJ in step S5 above, for example, is the forward acceleration at the time of starting or accelerating, etc. If attitude control has been carried out to suppress the vehicle body from collapsing until now, as the forward acceleration decreases, the attitude control tends to cause the vehicle body to swing forward. Therefore, in step 820 above, the air supply solenoid valve 1
9 and rear side solenoid pulps 25 and 26 are respectively turned on corresponding to the memory time (TM), and
If the small-diameter supply air flow path and exhaust flow path M have been set in step S8, the flow rate control valves 20 and 27 are also turned on in response to the meridian time (TM).

As a result, the rear suspension unit) R87,R
The main air of 82 is compressed air in the hole 3 through the solenoid pulp 25° 26, the exhaust flow 9 control valve 22, the small diameter M or large diameter exhaust flow path, the exhaust direction switching valve 28, and the residual pressure valve 29. The amount of air supplied during the above-mentioned Nuquot suppression,
In other words, the reserve tank 15 on the low pressure side for the time (TM)
is exhausted to b. In addition, compressed air from the reserve tank 15a on the high pressure side is supplied to the main air splash chamber 3 of the front side spring pump unit) FS1, FS2, and the air supply solenoid valve 19 and the small diameter L''! Diameter air supply flow path, air supply flow control valve 201 solenoid pulp 22
．． 23f, the amount of air exhausted during the above-mentioned null auto suppression, that is, the amount of time (TV) is supplied. As a result, the posture of the grass body is quickly returned to a steady state upon receiving the forward thrust, and the posture control by Nuquote is canceled. In this way, when the posture return control in step S20 is completed, step S21 Step S22 proceeds to step S22, where the memory for the valve on time (TM) and (TM) are cleared.

On the other hand, after starting attitude control in step 1312,
In step S16, the determination is ``YESJ'', that is, before the vehicle height average value (ma) reaches the target vehicle height CH), the acceleration G acting on the vehicle body decreases and the acceleration data (
ΣVG) has fallen below the first predetermined value B, the determination is "YES" in step S5 and rNO in step S19, and the process proceeds to step 823. In this step Szs, it is determined whether or not each attitude control valve is currently turned off. If the process proceeds to step f323 during attitude control as described above, the determination is "NO" and the process proceeds to step S24. , all control valves are turned off in the same way as the process in step S21 above.

Furthermore, even if it is determined that the acceleration data (ΣVG) of the acceleration G acting on the vehicle body is less than the first predetermined value B at the time of determination in step S5 for the first time after the start, "NO" is determined in step S19. It is determined and the process proceeds to step S23. In this case, in step S23, 1
'-YESJ is determined and the process returns to step S1.

Therefore, attitude control is started when the acceleration acting on the vehicle body reaches a predetermined value or more, and the attitude control state is maintained when the vehicle height of the front and rear of the vehicle body reaches the target vehicle height. Therefore, any change in attitude that may occur in the vehicle body is reliably suppressed regardless of its size.

In the above embodiment, the ON time (TM) and (TM/)' of each control valve when suppressing attitude change are stored in advance, and the attitude return control is performed based on the ON time (TM) and (TM). was executed so that the control amount of the attitude control during change suppression and attitude return is set to be equal. However, if the flowchart of the operation configuration shown in FIG. Time (TM)
It is possible to perform posture return control corresponding to the posture control amount when suppressing posture change without having to store it in memory in and (TM')'. In other words, this flowchart
In the posture @ return control part in step S2θ of FIG. 4 above, a routine is inserted in which steps 87 to 816 during posture change suppression, which are steps 830 to S37, are used for posture return control, and further steps in FIG. SI
4 and S22, and steps S5 and 81
Step 5stt is inserted between step 9 and step 9 to determine whether or not the posture control holding state has been released.

〔Effect of the invention〕

As described above, according to the present invention, when the acceleration sensor detects an acceleration in the front V direction of the vehicle body that is equal to or greater than a predetermined value, the spring reaction force of each suspension unit is adjusted so that the vehicle body posture is adjusted in a direction that counters the change in the vehicle body posture. When the control is started and the vehicle height of the front and rear of the vehicle reaches the target vehicle height corresponding to the reference posture of the storage body, the spring reaction force of each suspension unit '! i-
＆, so that even if, for example, the inertia of the vehicle body changes due to an increase or decrease in the number of passengers and the attitude change varies greatly, the attitude control can always be performed with the appropriate control M-. . As a result, changes in posture occurring in the longitudinal direction of the vehicle body can be reliably suppressed no matter how much force is applied.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an electronically controlled suspension device according to an embodiment of the present invention, FIGS. 2(E) and CB) are diagrams showing opening and closing operations of a three-way solenoid valve, and FIGS. B) ii' A diagram showing the opening/closing operation of the two-way solenoid valve, FIG. FIG. 5 is a flowchart showing the posture control operation according to another embodiment of the present invention. FSl, FS2...Front side Nubensilon unit), R8I, R82...Rear side Nuvensilon unit, 3...Air spring chamber, 15a, 15b...
Reserve tank, 19...Air supply solenoid valve, 2
2.23...Front side solenoid valve, 25.2
6...Rear side solenoid valve, 28...Exhaust direction switching valve, 3θ...#K solenoid valve, 3
1F...Front vehicle height sensor, 3JR...Rear vehicle height sensor, 34...Control unit, 36...
Acceleration layer sensor.

Claims (1)

[Claims] Suspension units are provided for each of the front and rear wheels, using both a fluid spring chamber and a coil spring, and are individually connected to the fluid spring chambers of each suspension unit to control the supply and discharge of fluid. When a control valve, an acceleration sensor that detects longitudinal acceleration acting on the vehicle body, a vehicle height sensor that detects the vehicle height of the front and rear of the vehicle body, and the acceleration sensor detect forward acceleration or backward acceleration of a predetermined value or more The front wheel side control valve or the rear wheel side control valve is actuated to control the vehicle body in a direction that opposes the change in vehicle body posture until the vehicle height of the front and rear portions of the vehicle body detected by the vehicle height sensor reaches the target vehicle height. An electronically controlled suspension device comprising a control means for performing control.