JPS6337722B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to vehicle height control, and in particular, detects the height between an axle and a vehicle body frame with a vehicle height detector,
The present invention relates to vehicle height adjustment that controls the fluid pressure of a suspension system in correspondence with the detected vehicle height to maintain the vehicle height within a predetermined range. In this type of vehicle height adjustment, for example, as disclosed in U.S. Pat. It processes to obtain a signal that energizes the vehicle height adjustment drive system, and provides this signal to the vehicle height control circuit, which lowers the fluid pressure in the suspension system when the vehicle height is "high" in the drive system, and sets the vehicle height to "low". When , the fluid pressure is increased. Therefore, in order to prevent repeated fluid pressure reduction operations when the detected vehicle height vibrates near the boundary between "medium" and "high",
In order to prevent repeated fluid pressure raising operations when vibrating near the boundary between and "low", the vehicle height control circuit generally includes a vehicle height "high" signal processing system and a vehicle height "low" signal processing system. each includes one set of rise delay circuits. The vehicle height adjustment drive system usually includes an air compressor and an exhaust electromagnetic valve, and when raising the vehicle height, the air compressor is driven to supply pressurized air to the air chamber of the suspension system. When lowering the vehicle height, the solenoid valve is energized to open and releases air from the air chamber of the suspension system. When the vehicle height is at an appropriate value, the air compressor is stopped and the solenoid valve is closed (de-energized). When the discharge capacity of the air compressor is small and/or when raising the vehicle height quickly, an air accumulator (pressure accumulator) is provided. Supply pressurized air to the device. However, the speed of raising the vehicle height is also affected by the volume and internal pressure of the accumulator, and there are limits to these naturally.As a result, due to the correlation between the vehicle height adjustment mode and the accumulator pressure accumulation control, the accumulator pressure is lower than the suspension system while the vehicle height is not raised sufficiently. The air pressure decreases to the same extent as the air pressure of the air compressor, and the accumulator becomes a load on the air compressor, which may actually reduce the vehicle height raising speed. SUMMARY OF THE INVENTION An object of the present invention is to improve the reduction in the vehicle height raising speed caused by the accumulator when raising the vehicle height, and to improve the operating efficiency of the air compressor for raising the vehicle height. The vehicle height adjustment device of the present invention that achieves this objective has the following features:
Vehicle height detector; Accumulator; Pressure detection means for detecting the pressure of the accumulator; Air chamber opening/closing solenoid valve inserted between the air chamber of the suspension system and the accumulator; Interposed between the air chamber opening/closing solenoid valve and the accumulator and a check valve means that allows pressure to propagate from the accumulator to the air chamber opening/closing solenoid valve but prevents the opposite propagation, and flow only through the check valve means between the accumulator and the air chamber opening/closing solenoid valve. a solenoid valve means for selectively setting a first flow path to allow pressure to propagate from the processing chamber opening/closing solenoid valve to the accumulator; and a flow path switching means for opening and closing between the air chamber and low pressure. low-pressure opening/closing solenoid valve; an air compressor with a high-pressure outlet communicating with the air flow path between the air chamber opening/closing solenoid valve and the flow path switching means; , vehicle height raising control means that drives the air compressor, opens the air chamber opening/closing solenoid valve, sets the solenoid valve means of the flow path switching means to the first flow path, and closes the low pressure opening/closing solenoid valve; vehicle height detector; A vehicle height lowering control means for opening a solenoid valve in an air flow path between the air chamber and the low pressure in response to detection of the vehicle height; When the high-pressure discharge port of the air compressor is isolated from the air chamber and low pressure, if the pressure detection means detects a pressure below a certain level, the air compressor is driven and the solenoid valve means of the flow path switching means is activated. A pressure accumulation control means with two flow path settings is provided. According to this, when the vehicle height detection means detects that the vehicle height is low, the vehicle height raising control means drives the air compressor to open the air chamber opening/closing solenoid valve, and the solenoid valve means of the flow path switching means is activated. The low pressure on/off solenoid valve is kept closed for the 1 flow path setting. In this state, if the pressure in the accumulator is higher than the pressure in the air chamber of the suspension system, high-pressure air is supplied to the air chamber of the suspension system from the accumulator and the air compressor, and the pressure in the air chamber of the suspension system increases at an extremely high speed. rises. In other words, the vehicle height increases at extremely high speeds. When the pressure in the accumulator falls below the pressure in the air chamber of the suspension system, the supply of air from the accumulator to the air chamber stops, but the compressor continues to supply air. At this time, since there is a check valve means between the air chamber and air compressor of the suspension system and the accumulator, air is not supplied to the accumulator from the air chamber and air compressor of the suspension system, and the accumulator is connected to the compressor. It does not become a burden on the user. That is, the compressor supplies air only to the air chamber of the suspension system, and the compressor operates with high efficiency to raise the vehicle height. Therefore, although the speed is lower than when the pressure in the accumulator is higher than the pressure in the air chamber, the speed is relatively higher than in the conventional case where the compressor supplies air to both the air chamber and the accumulator. The pressure in the air chamber of the suspension system increases.
In other words, the vehicle height increases at a relatively high speed. When the vehicle height detection means detects the height of the vehicle, the vehicle height lowering means opens the solenoid valve in the air flow path between the air chamber and the low pressure, thereby lowering the air in the air chamber of the suspension system to the low pressure. The vehicle is ejected toward the vehicle, lowering the vehicle height. If the pressure of the accumulator is less than a certain pressure while the air chamber opening/closing solenoid valve and the low pressure opening/closing solenoid valve are cutting off the air compressor from the air chamber of the suspension system and low pressure, the pressure accumulation control means drives the air compressor. The solenoid valve means of the flow path switching means is set to the second flow path. As a result, high-pressure air is supplied from the air compressor to the accumulator through the flow path switching means, and the pressure in the accumulator increases, causing the accumulator to accumulate high-pressure air for the next vehicle height increase (accumulation pressure). ). In a preferred embodiment of the present invention, the flow path switching means includes a magnetic plunger having a check valve member that faces the opening of the accumulator communication port and is movable toward and away from the opening. The electromagnetic check valve is provided with a spring that biases toward the opening, and an electric coil that drives the magnetic plunger away from the opening in response to energization. With this electromagnetic check valve, by keeping the electric coil de-energized when raising the vehicle height, the pressure in the accumulator is lower than the pressure in the air chamber of the suspension system (more precisely, the pressure plus the spring pressure). When high, the accumulator pressure is applied to the opening of the accumulator communication port, pushing the check valve member into the plunger working space and through the output port to the air chamber of the suspension system. When the pressure of the accumulator becomes lower than the pressure of the air chamber, the inflow of air from the accumulator stops, and the high pressure from the air chamber side presses the check valve member against the opening of the accumulator communication port, so it communicates with the air chamber of the suspension system. Air does not flow from the plunger operating space to the accumulator. When accumulating pressure, the electric coil is energized. As a result, the check valve member moves away from the opening of the accumulator communication port against the repulsive force of the spring, the plunger operating space and the accumulator communication port communicate with each other, and the air discharged by the compressor is supplied to the accumulator. In this way, the flow path switching means has a relatively simple structure.
It can be configured with several solenoid valves. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings. FIG. 1a shows how the vehicle height detector 100 used in the embodiment of the present invention is attached to a vehicle. The vehicle height detector 100 is fixed to the vehicle body frame 10, and one end of a link 20 is connected to its rotating shaft, and the other end of the link 20 is connected to the outer case of the differential gear 30. 40 is an axle. A cross-sectional view of the vehicle height detector 100 is shown in FIG. 1b. In the vehicle height detector 100, the rotation axis 1
A light shielding plate 105 having an arc-shaped fold 104 is fixed to the tip of the link 03, and a link 2 is attached to the other end.
0 is fixed. A printed circuit board 107 is fixed to the base 106, and photo sensors 101 and 102 are fixed to this printed circuit board 107. 1e to 1c are cross-sectional views taken along the - line in FIG. 1b. Note that FIG. 1e shows a state in which the vehicle height is "high," FIG. 1d shows a state in which the vehicle height is "medium," and FIG. 1c shows a state in which the vehicle height is "low." The photo sensors 101 and 102 are composed of a light emitting diode and a photo transistor as shown in FIG.
4 blocks it. Photo sensor 10 according to vehicle height
The outputs c and b (Fig. 2) of No. 1,102 are shown in Table 1 below.

[Table] FIG. 2 shows an embodiment of the present invention. In this, reference numerals 101 and 102 are photo sensors of the vehicle height detector 100, which are connected to a control device 120. The control device 120 includes a pulse oscillator 130, a counter CO2, and inverters IN2 to IN5,
It consists of logic circuits such as OR gates OR2 and OR3. In the vehicle height drive system 200, the first electromagnetic on-off valve SOL1 is placed between the suspension system 400 and the air compressor 203, and the second electromagnetic on-off valve SOL2 is placed between the accumulator 330 and the air compressor 203.
It is inserted between the third electromagnetic on-off valve SOL
3 is connected to the air compressor 203 and the first and second electromagnetic on-off valves. For all of these electromagnetic on-off valves, when the solenoid is energized, communication between the energized and output ports is established (valve open), and when the solenoid is not energized, the energized and output ports are connected (valve open).
This shuts off (closes the valve) between output ports. A pressure detection switch 340 is connected to the accumulator 330 and is closed (on) when the pressure is above a predetermined pressure and opened (off) when the pressure is below a predetermined pressure. One end of this switch is grounded, and the other end is connected to the control device 120, and when the accumulator pressure is above a predetermined value, the terminal on the control device 120 side of the switch 340 becomes a low level L (“0”), and the predetermined value High level H below
(“1”). An electromagnetic check valve SOL-CE is inserted between the accumulator communication port of the second electromagnetic valve SOL2 and the accumulator 330. Figure 3 shows the structure of the electromagnetic check valve SOL-CE. In FIG. 3, an accumulator communication port 310a is located in the center of a non-magnetic face plate 310, and a solenoid valve SOL2 is connected to the communication port 310a on the side thereof.
s is opened, and the port 310a is connected to the valve body 31.
1 is closed. The valve body 311 is fixed to a magnetic plunger 312, and this plunger 312
is pushed toward the face plate 310 by a compression coil spring 313. One end of a magnetic cylinder 314 forming a part of the electromagnetic check valve case is fixed to the face plate 310. cylinder 314
A magnetic end plate 315 is fixed to the other end,
One end of a magnetic core 316 is fixed to the center, and the other end of the core 316 supports one end of a spring 313. A bobbin 318 around which an electric coil 317 is wound is held between an end plate 315 and a magnetic end plate 319. 320 ₁ and 320 ₂ are O for airtightness
It's a ring. In FIG. 3, the cross-hatched members are magnetic materials, and when the electric coil 317 is energized, the plunger 312 is attracted to the core 316, the valve body 311 is separated from the port 310a, and the ports 310a and 310s are separated. communicate. When electric coil 317 is de-energized (de-energized), port 3
When the pressure of port 10a is higher than the pressure of port 310s by a predetermined pressure (determined by the repulsive force of spring 313), valve body 311 is pushed and port 310a is
10s, but when the pressure of the port 310a (the pressure of the accumulator 330) is low, the third
As shown in the figure, the valve body 311 closes the port 310a and blocks the ports 310a-310s.
That is, the electromagnetic check valve SOL-CE operates as a check valve when the electric coil 317 is de-energized,
When the electric coil 317 is energized, the valve is open. Next, the operation of the vehicle height drive system 200 will be explained. Second
Referring to the figure, when the second solenoid valve SOL2 and the solenoid check valve SOL-CE are opened, the compressor 20
3, pressurized air is supplied to the accumulator 330 (pressure accumulation). When the first and second solenoid valves SOL1 and SOL2 are both opened and the compressor 203 is driven, the suspension system 400 will notice that if the pressure in the accumulator 330 is high, the accumulator 330
Air is supplied from 30 and air compressor 203 (rapid vehicle height raising). Accumulator 33
If the pressure in the accumulator 330 decreases or if the pressure in the accumulator 330 is low from the beginning, the valve body 311 of the electromagnetic check valve SOL-CE shuts off between the accumulator 330 and the electromagnetic valve SOL2, so that the suspension system 400 Only the air compressor 203 supplies air (to raise the vehicle height when the accumulator pressure is exhausted). In this case, the accumulator 330 is
Suspension device 400 and air compressor 203
It does not become a load on the When the first and third solenoid valves SOL1 and SOL3 are energized (opened),
Air in the suspension system 400 is released to atmospheric pressure through SOL1 and SOL3, and the vehicle height is lowered (vehicle height lowering). The first to third solenoid valves SOL1 to SOL3 and the solenoid check valve SOL-CE are connected to amplifiers AMP1 to AMP1, respectively.
5. Receive electricity from each of 5. The air compressor 203 is driven by the motor 202.
02 is rotationally energized when relay 201 is closed.
When relay 201 receives power from amplifier AMP4, it closes and energizes motor 202. Next, the states of input/output signals a to i of the control device 120 are shown in Table 2 below, and its operation will be explained.

[Table] First, the operations of counters CO2 and CO3 will be explained. Counters CO2 and CO3 are in the clear state when their CLR inputs are high. Inverter IN3 is connected between the CLR input terminal and the signal c and b lines.
Since IN2 is inserted, counters CO2 and CO3 are cleared while signals c and b are low. In other words, the counter CO2 is cleared at "high" and "medium" vehicle heights, and the counter CO2 is cleared at "high" and "medium" vehicle heights.
CO3 is cleared at "low" and "medium" vehicle heights. When the vehicle height changes from "medium" to "low",
Signal b changes from L to H, CLR of counter CO2
The input terminal changes from H to L and the counter CO2 starts counting up. Counter CO2 counts the output pulses of oscillator 130. If the vehicle height does not return to "medium" at least once after t _d = 10 seconds after starting counting, the counter CO2
_Q3 output terminal becomes H, counter CO2 stops counting up, vehicle height increase instruction d=H is applied to OR gates OR2 and OR3, and its inverted signal g=
L is applied to AND gate AN1. Therefore, f=i=H, the compressor 203 is driven, and the solenoid valves SOL1 and SOL2 are opened. At this time, if the air pressure of the accumulator 330 is higher than the air pressure of the suspension system, the valve element 311 of the electromagnetic check valve SOL-CE is opened by the air pressure of the accumulator, and air is sent from the compressor 203 and the accumulator 330 to the suspension system 400. , when the pressure in the accumulator 330 is low, only the compressor 203 supplies air to the suspension system 400. Note that if the vehicle height returns to "medium" within _td after becoming "low", the counter CO2 is cleared, so the vehicle height raising operation is not started. When the vehicle height becomes "medium" after the start of the vehicle height raising operation, the counter CO2 is cleared at that point, so the vehicle height raising operation is immediately reset. When the vehicle height changes from "medium" to "high," counter CO3 performs an operation similar to that of CO2 described above. In this case, Q ₃ output e of counter CO3
is applied to the OR gates OR2 and AMP3, so the solenoid valves SOL1 and SOL3 are opened, and the air in the suspension system 400 is discharged to the atmosphere through them. Using counters CO2 and CO3, when the vehicle height is switched from "medium" to "low" or "high", the vehicle height is not raised or lowered immediately; If the vehicle continues for t _d , it will start raising or lowering the vehicle height after t _d , and when the vehicle height returns to "medium", it will immediately raise and stop lowering at the moment when the vehicle height responds to the vibration. This is to prevent the drive system from being energized during a normal shift. Such control delay prevents the drive system from repeatedly energizing and stopping, thereby stabilizing the vehicle height. Next, the accumulation of pressure in the accumulator 330 will be explained.
As shown in Table 2, the pressure is stored in the accumulator 33.
0 pressure is low (340 open, a=H), vehicle height is "medium"
This is continued until the switch 340 is closed (a=L). FIG. 4 shows another embodiment of the invention. In this case, the control device 120 is constituted by a one-chip microcomputer (hereinafter referred to as microcomputer) MPU. The ROM of the microcomputer MPU contains program data that starts when the power is turned on and monitors the states of the vehicle height detector 100 and pressure switch 340, and performs vehicle height control and pressure accumulation control according to these states. is stored. Microcomputer based on the program data
Figure 5 shows the control operation of the MPU. Note that in FIG. 5, a register refers to one memory area of the RAM of the MPU, and a timer refers to execution of a program timer that counts a set number of clock pulses (or timing pulses). The control operation of the MPU will be explained below with reference to FIG. First, the registers and memory contents shown in FIG. 5 are shown in Table 3 below.

[Table] When the MPU is powered on, it clears the registers and output ports (611 to 615 = L), and after a predetermined timing, input ports 601,
Read 602 and 603 and store their input states in the input register. Next, refer to the memory contents of the input register and determine the vehicle height based on the height of the signals c and b read into the input register. If the vehicle height is "low", add 1 to the low register and store it in memory. Compare it with a predetermined number n, and if the memory content < n, the input port is read back, and if the memory content ≧ n, 1 is subtracted from the low register and stored, and just in case, the output ports 613 and 614 are cleared and the electromagnetic valve
Reset SOL-CE and SOL3 to close, set H to output ports 611, 612, and 615, open solenoid valves SOL1 and SOL2, and drive air compressor 203. Note that when the content of the low register is less than n, the "low" state has not continued for more than the delay time _t0n , so the aforementioned vehicle height raising set is not performed. This delay time t ₀ n is determined by the counter in Figure 2.
Corresponds to the delay time of CO2. When the vehicle height is "high", the vehicle height is set to be lowered using the same flow with a delay time t ₀ n. However, in this case, air is released from the suspension system 400, so solenoid valve SOL2 is closed, compressor 203 is stopped,
and set the solenoid valves SOL1 and SOL3 open. When the vehicle height is "medium", the high register and
Clear both low registers and solenoid valves SOL1 to SOL
3 and SOL-CE are set to closed, and air compressor 230 is set to stopped. When the vehicle height is "medium" and the pressure switch 340 is open (low pressure), SOL2 and SOL-CE are opened to drive the compressor 203. In the embodiment shown in FIG. 6a, a fourth on-off solenoid valve SO4 is inserted between the accumulator 330 and the solenoid valve SOL2, and a check valve CE is connected in parallel to it. The operation of this embodiment is the same as that of the embodiment shown in FIG. In the embodiment shown in FIG. 6b, a third solenoid valve SOL3 is connected directly to the suspension 400, and a check valve is connected in parallel to the second solenoid valve SOL2.
CE is connected. In this example,
Solenoid valve SOL only when accumulating pressure in the accumulator
In order to open the solenoid valve SOL2, the solenoid valve SOL2 is biased open by the signal h. Further, when lowering the pressure of the suspension system 400, it is necessary to keep the solenoid valve SOL1 closed, so the solenoid valve SOL1 is biased open by the signal d. In the embodiment shown in FIG. 6c, the solenoid valve SOL2 and check valve CE of the embodiment shown in FIG.
The configuration has been changed to one electromagnetic check valve SOL-CE as shown in the figure. This electromagnetic check valve SOL-CE is No.6b
It is energized in the same way as the solenoid valve SOL2 shown in the figure. As described above, according to the vehicle height adjustment device of the present invention, when the vehicle height detection means 100 detects that the vehicle height is low, the vehicle height raising control means 120 controls the air compressor 203.
, and open the air chamber opening/closing solenoid valve SOL1.
The flow path switching means SOL-CE, SOL4 and the solenoid valve means of CE maintain the first flow path setting (check valve flow), and the low pressure on-off solenoid valve SOL3 remains closed. In this state, if the pressure in the accumulator 330 is higher than the pressure in the air chamber of the suspension system 400, high-pressure air is supplied from the accumulator 330 and the air compressor 203 to the air chamber of the suspension system 400, and the suspension system 400
The pressure in the air chamber increases at an extremely high rate. In other words, the vehicle height increases at extremely high speeds. When the pressure of the accumulator 330 becomes lower than the pressure of the air chamber of the suspension system 400, the supply of air from the accumulator 330 to the air chamber of the suspension system 400 stops, but the compressor 203 continues to supply air. At this time, since there is a check valve means between the air chamber of the suspension device 400 and the air compressor 203 and the accumulator 330, air is supplied from the air chamber of the suspension device 400 and the air compressor 203 to the accumulator 330. Therefore, the accumulator 330 does not become a load on the compressor 203. That is, the compressor 203 supplies air only to the air chamber of the suspension system 400,
The operating efficiency of the compressor 203 for raising the vehicle height is high. Therefore, although the speed is lower than when the pressure in the accumulator 330 is higher than the pressure in the air chamber, the speed is relatively lower than in the conventional case where the compressor supplies air to both the air chamber and the accumulator. At high speeds, the pressure in the air chamber of suspension system 400 increases. In other words, the vehicle height increases at a relatively high speed.

[Brief explanation of the drawing]

FIG. 1a is a side view showing how the vehicle height detector 100 is mounted in an embodiment of the present invention, and FIG. 1b is a sectional view of the vehicle height detector 100. Figures 1c, 1d and 1e are sectional views taken along the - line in Figure 1b, each showing different operating conditions. FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is an enlarged side view of the electromagnetic check valve SOL-CE shown therein. FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG. 5 is a flowchart showing the control operation of the microcomputer MPU shown therein. Figures 6a, 6b and 6c are block diagrams showing other embodiments of the present invention. 10: Vehicle body frame, 20: Link, 30: Differential gear, 40: Axle, 100: Vehicle height detector (vehicle height detector), 101, 102: Photo sensor, 103: Rotating shaft, 104: Light shielding plate 105
120: Vehicle height adjustment control device (vehicle height raising control means, vehicle height lowering control means, pressure accumulation control means),
130: Clock pulse generator, CO2, CO3:
Counter, 201: Relay, 202: Motor, 2
03: Air compressor (air compressor), SOL1: Solenoid valve (air chamber opening/closing solenoid valve),
SOL2: Solenoid valve, SOL3: Solenoid valve (low pressure opening/closing solenoid valve), SOL-CE: Solenoid check valve (flow path switching means),
SOL4: Solenoid valve (solenoid valve means for flow path switching means),
CE: Check valve (check valve means for flow path switching means), 33
0: Akiyumurator (Akiyumurator), 34
0: Pressure switch (pressure detection means), MPU: Microcomputer.

Claims (1)

[Scope of Claims] 1 Vehicle height detector; Accumulator; Pressure detection means for detecting the pressure of the accumulator; Air chamber opening/closing solenoid valve inserted between the air chamber of the suspension system and the accumulator; Air chamber opening/closing solenoid valve A check valve means is inserted between the accumulator and the air chamber opening/closing solenoid valve, and allows pressure to propagate from the accumulator to the air chamber opening/closing solenoid valve, but prevents pressure from propagating in the opposite direction. A flow path switching means comprising: a first flow path setting that allows flow to flow only through the air chamber; and a second flow path setting that allows pressure to propagate from the air chamber opening/closing solenoid valve to the accumulator; A low-pressure on-off solenoid valve that opens and closes between the chamber and low pressure; An air compressor in which a high-pressure discharge port communicates with the air flow path between the air chamber on-off solenoid valve and the flow path switching means; A vehicle height detector that controls the vehicle height. In response to low detection, the air compressor is driven, the air chamber opening/closing solenoid valve is opened,
Vehicle height raising control means for setting the solenoid valve means of the flow path switching means to the first flow path and closing the low pressure on/off solenoid valve; A vehicle height lowering control means that opens a solenoid valve in an air flow path between the low pressure; and the air chamber opening/closing solenoid valve and the low pressure opening/closing solenoid valve shut off the high pressure discharge port of the air compressor from the air chamber and the low pressure. If the pressure detection means detects a pressure lower than a certain pressure, the air compressor is driven, and the solenoid valve means of the flow path switching means is set to the second flow path.
A vehicle height adjustment device comprising: pressure accumulation control means; 2. The flow path switching means includes a magnetic plunger that faces the opening of the accumulator communication port and has a check valve member that can move toward and away from the opening, and urges the magnetic plunger in the direction toward the opening. 2. The vehicle height adjusting device according to claim 1, which is an electromagnetic check valve comprising a spring that moves the magnetic body and an electric coil that drives the magnetic plunger in a direction away from the opening in response to energization. 3. The flow path switching means is interposed between the air chamber opening/closing solenoid valve and the accumulator, and includes a check valve that allows pressure to propagate from the accumulator to the air chamber opening/closing solenoid valve but prevents pressure from propagating in the opposite direction; The vehicle height adjustment according to claim 1, comprising a solenoid valve that is inserted between the chamber opening/closing solenoid valve and the accumulator, and selectively opens and closes the air flow path between the accumulator and the air chamber opening/closing solenoid valve. Device.