JPH02155814A - Car height adjusting device - Google Patents

Abstract

PURPOSE:To reduce the pressure withstanding strength of an oil cooler by connecting the exhaust passage with the supply passage for the working fluid for car height adjusting actuator through a bypass valve, which is so arranged as to open gradually when operation is stopped. CONSTITUTION:A timer is actuated to set the time Toff at which a main relay is turned off when an ignition switch is put off. A control part determines the supply current Ib to the solenoid 190 of a solenoid opening/closing valve 186 on the basis of the relation map between time and current. The current Ib determined is supplied to the solenoid opening/closing valve 186, to open a bypass valve 196 gradually. When the Off time has passed, the main relay is turned off. This constitution can avoid a large quantity of working fluid from abruptly flowing via bypass valve when the operation is stopped, which will reduce the pressure withstand strength of an oil cooler etc.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a vehicle height adjustment device for a vehicle such as an automobile.

Conventional technology A vehicle height adjustment device for a vehicle such as an automobile has generally been installed corresponding to each wheel of the vehicle, and the height adjustment device is generally installed at a position corresponding to each wheel by supplying and discharging working fluid to a working fluid chamber. A plurality of actuators that increase and decrease the vehicle height, a working fluid supply passage means for supplying working fluid to a working fluid chamber, a working fluid discharge passage means for discharging working fluid from the working fluid chamber, a working fluid supply passage means and an operation. It has a control valve provided in the middle of the fluid discharge passage means to control the supply and discharge of the working fluid to and from the working fluid chamber, and by controlling the control valve, the working fluid can be selectively supplied and discharged from the working fluid chamber. This allows the vehicle height to be selectively increased or decreased.

As one of such vehicle height adjustment devices, a patent application filed in 1983 filed by the same applicant as the applicant of the present application was filed.
The issue is a vehicle height adjustment device in which a bypass valve that is selectively connected to the operational fluid supplier and the operating fluid emission means. According to this vehicle height adjustment device, by controlling the pressure in the first stage of the working fluid supply passage by opening and closing the bypass valve, it is possible to open and close the cutoff valve that opens and closes in response to the pressure.

Problems to be Solved by the Invention When the bypass valve is suddenly opened when the vehicle height adjustment device incorporating the bypass valve is stopped, generally speaking, the amount of water in the accumulator provided in the working fluid supply passage means is increased. A relatively large amount of working fluid rapidly flows from the working fluid supply passage means to the working fluid discharge passage means via the bypass valve;
As a result, the pressure within the working fluid discharge passage means temporarily increases rapidly. Therefore, there is a problem in that the pressure resistance strength of the working fluid discharge passage means and the oil cooler, filter, etc. provided therein must be set much higher than the strength required for normal operation of the vehicle height adjustment device. .

In view of the above-mentioned problems in the conventional vehicle height adjustment device, the present invention has been developed in such a way that, when the vehicle is stopped, a relatively large amount of working fluid suddenly flows from the working fluid supply passage means to the working fluid discharge passage means via the bypass valve. This vehicle has been improved so that it can operate satisfactorily over a long period of time without having to set the pressure resistance of the working fluid discharge passage means and the oil cooler, filter, etc. installed therein to be higher than necessary. The purpose is to provide a vehicle height adjustment device.

Means for Solving the Problems According to the present invention, the above-mentioned object is achieved by supplying and discharging working fluid to the working fluid chambers provided corresponding to each wheel of the vehicle. a plurality of actuators that increase or decrease the vehicle height; a working fluid supply passage means for supplying working fluid at a supply pressure to the working fluid chamber; a working fluid discharge passage means for discharging working fluid from the working fluid chamber; a bypass valve that selectively communicates and connects the fluid supply passage means and the working fluid discharge passage means, and a bypass valve located in the middle of the working fluid supply passage means and the working fluid discharge passage means between the bypass valve and the actuator. A control valve is provided to control the supply and discharge of working fluid to and from the working fluid chamber, and a control means for controlling the bypass valve and the control valve, and the control means gradually opens the bypass valve when the operation is stopped. This is achieved by a vehicle height adjustment device configured to

Effects and Effects of the Invention According to the configuration as described above, the control means is configured to gradually open the bypass valve when the vehicle height adjustment device stops operating, and therefore the bypass valve gradually opens when the vehicle height adjustment device stops operating. As a result, the degree of communication between the working fluid supply passage means and the working fluid discharge passage means by the bypass valve is gradually increased, whereby the flow rate of the working fluid flowing from the working fluid supply passage means through the bypass valve to the working fluid discharge passage means is increased. or gradually increased. Therefore, when the vehicle height adjustment device stops operating, a relatively large amount of working fluid rapidly flows from the working fluid supply passage means to the working fluid discharge passage means via the bypass valve, resulting in pressure in the working fluid discharge passage. This prevents a sudden sudden increase in the amount of water, so the durability of the working fluid discharge passage means and the oil cooler, filter, etc. installed therein can be improved without having to set the pressure resistance to an unnecessarily high level. This allows the vehicle height adjustment device to operate satisfactorily over a long period of time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

Embodiment FIG. 1 is a schematic diagram showing an embodiment of the vehicle height adjustment device for heavy wheels according to the present invention. The vehicle height adjustment device shown in the figure is an actuator I provided corresponding to a right front wheel, a left front wheel, a right rear wheel, and a left rear wheel of the vehicle, which are not shown in the figure.
PR, I PL, 1. , RR, I RL, and each of these actuators has a working fluid chamber 2P.
It has R,2+211.2RR,2RL.

Further, in the figure, 4 indicates a reserve tank that stores hydraulic oil as a working fluid, and the reserve tank 4 is connected to a suction flow path 10 in which a filter 8 for removing foreign matter is provided in the middle.
It is connected in communication with the suction side of the pump 6. A drain passage 12 is connected to the pump 6 for collecting working fluid leaked inside the pump 6 into the reserve tank 4. The pump 6 is rotationally driven by an engine 14, and the rotation speed of the engine 14 is detected by a rotation speed sensor 16.

A high pressure flow path 18 is connected to the discharge side of the pump 6.

A check valve 20 is provided in the middle of the high-pressure flow path 18 to allow only the flow of working fluid from the pump toward each actuator, and between the pump 6 and the check valve 20, the working fluid discharged from the pump is provided. An attenuator 22 is provided to absorb pressure pulsations and reduce pressure changes. The high pressure flow path 18 includes a front wheel high pressure flow path 18F and a rear wheel high pressure flow path 1.
8R is connected to one end, and accumulators 24 and 26 are connected to these high pressure channels, respectively.

Each of these accumulators has a high pressure gas sealed therein so as to absorb pressure pulsations of the working fluid and perform a pressure accumulating function.

Further, one ends of the high pressure flow path 18PR for the right front wheel, the high pressure flow path 18PL for the left front wheel, the high pressure flow path 18RR1 for the right rear wheel, and the high pressure flow path 18R1 for the left rear wheel are connected to the high pressure flow paths 181' and 18R, respectively. There is. High pressure flow path 18PR.

18P+4.18 RR, 181? In the middle of L are filters 28 P+? , 28 FL, 28 R1?
, 28RL are provided, and the other ends of these high-pressure flow paths are pilot operated three-port switching control valves 40, 42, 44 .
46 P ports.

The pressure control valve 32 is connected to the switching control valve 40 and the high pressure flow path 18P.
It consists of a flow path 50 that communicates and connects the low pressure flow path 48PR for the right front wheel, and a fixed throttle 52 and a variable throttle 54 provided in the middle of the flow path.

A low pressure passage 48PR is connected to the R port of the switching control valve 40, and a connection passage 56 is connected to the A port. The switching control valve 40 has a fixed throttle 52 and a variable throttle 54.
It is a spool valve that takes in the pressure Pp in the flow path 50 between and the pressure Pa in the connection flow path 56 as pilot pressure, and when the pressure Pp is higher than the pressure Pa, it is a switching valve that connects port P and port A for communication. When the pressures Pp and Pa are equal to each other, the switching position 40a is switched to the switching position 40b where communication of all ports is cut off, and the pressure Pp is switched to the switching position 40b.
When the pressure is lower than the pressure Pa, the switch is switched to a switching position 40c in which port R and port A are connected in communication. In addition, the 1-variable throttle 54 changes the effective passage cross-sectional area of the throttle by controlling the current supplied to its solenoid 58, thereby working together with the fixed throttle 52 to create a pressure Pp.
It is designed to change the

Similarly, pressure control valves 34 to 38 are each pressure control valve 32
A pilot-operated three-port switching control valve 42, 44, 46 corresponding to the switching control valve 40, a flow path 60, 62, 64 corresponding to the flow path 50, and a fixed throttle 66, 68 corresponding to the fixed throttle 52. .70 and variable apertures 72, 74, and 76 corresponding to the variable aperture 54, and the variable apertures 72 to 76 each have a solenoid 78, 80, and 82.

In addition, the switching control valves 42, 44, and 46 are switching control valves 40
The R port has a low pressure flow path 48FL for the left rear wheel and a low pressure flow path 48R for the right rear wheel, respectively.
One end of a low pressure flow path 48RL for the R and left rear wheels is connected to the A port, and one end of connection flow paths 84, 86, and 88 are connected to the A port, respectively. Moreover, each of the switching control valves 42 to 46 has a flow path 60 between a corresponding fixed throttle and a variable throttle.
It is a spool valve that takes in the pressure Pp in ~ 64 and the pressure Pa in the corresponding connection channels 84 ~ 88 as pilot pressure, and when the pressure Pp is higher than the pressure Pa, the switching position connects port P and port A for communication. 42a, 44a
, 46a, and the switching position 42 cuts off communication of all ports when the pressures Pp and Pa are equal to each other.
b , 44b , 46b , and the pressure Pp becomes the pressure P
When it is lower than a, the switching positions 42c s 44e and 46c connect port R and port A in communication.

As schematically shown in FIG. 1, each actuator 11'R, IRR, IRL has a cylinder 1.06I'R,], 06r'L, 1061?, respectively. Ii,
1061n1. and the working fluid chamber 2P+? are fitted into the corresponding cylinders and work together with the corresponding cylinders. , 2P
L, 2+? Piston 108FR defining R12RL,
1081'l,,1081? R, 108 old 4, and each cylinder is connected to a central suspension not shown in the diagram, and the tip of the piston rod is connected to a suspension arm not shown in the diagram. .

Also, the cylinders 106FR and 106P of each actuator
+7. Drain passage for 1.06RR, 106R1] 1
One end of 0.112.114.116 is connected.

The other end of the drain channel 110.112.1]4.116 is connected to the drain channel]18, which is connected to the reserve tank 4 via a filter 120, whereby the working fluid Working fluid leaking from the chamber is returned to the reserve tank.

Working fluid chambers 212R, 2PL, 21? R, 2+? Accumulators 132, 134, 136, 138 are connected to each of L via a throttle 124, 126, 128, 130. Also piston 108PR, 1,08PL
, 1081? R, 1, 08RL each have a flow path 140.
r'R, 140PL, 140RR, 140RL are provided. Each of these channels is a corresponding channel 56.
．． 84 to 88 and working fluid chamber 2 PR, 2PL, 21 state,
2RL, and a filter 142 is installed in the middle of each.
PR, 142p+,, 142R1? , 1421? L
have. Also, actuators I FR, I FL
, 11? At a position close to R and IRL, a vehicle height sensor 144Fl? detects the distance between the vehicle body and the corresponding wheel.
, 144 PL, 144 I? I? , 1.441? L is provided.

Pilot-operated cutoff valves] 50.152.154.156 are provided in the middle of the connection channels 56.84 to 88, respectively, and these cutoff valves are connected to corresponding pressure control valves 40.42.44. High pressure flow path 1 upstream from 46
8FR, 18FL, 181? R, 181?1. When the pressure difference between the pressure inside and the pressure inside the drain flow path 110.112.114.116 is below a predetermined value, the valve is kept closed. In addition, the portions of the connection channels 56.84 to 88 between the corresponding pressure control valves and the cutoff valves are connected to the flow channels 158.160, 162.164, respectively, and the flow channels 50.60.62.64 of the corresponding pressure control valves. It is connected to the downstream part of the variable throttle. Channels 158 to 164
Relief valves 166, 168, 170 are installed in the middle of each
．． 172, each of these relief valves takes in the pressure at the upstream side of the corresponding flow path 158, 160, 162, 164, that is, the corresponding connection flow path side, as a pilot pressure, and from the pilot pressure. When a predetermined value is exceeded, the valve is opened to guide a portion of the working fluid in the corresponding connection flow path to the flow paths 50, 60 to 64.

The cutoff valves 150 to 156 are connected to the high pressure flow path 18 r', respectively.
The valve may be configured to maintain the valve closed state when the pressure difference between the pressure in R, 18P+, 18RR, and 18RL and the atmospheric pressure is equal to or less than a predetermined value.

Low pressure flow path 481N? The other end of 48PL and 48PL are connected to one end of the low pressure flow path 48F for the front wheels, and the low pressure flow path 481? I
? And the other end of ML is the low pressure flow path 481 for the rear wheels. Part 3 is connected to the end. Low pressure flow path 4812 and 48R
The other end is connected to one end of the low pressure flow path 48 . The low pressure flow path 48 has an oil cooler 174 in the middle, and is connected to the reserve tank 4 via a filter 176 at the other end. Check valve 20 and attenuator 22 of high pressure flow path 18
The portion between is connected to the low pressure flow path 48 by a flow path 178. A relief valve 180 is provided in the middle of the flow path 178 and is set to a predetermined pressure in advance.

In the illustrated embodiment, the high pressure channel 18R and the low pressure channel 4
8R is a flow path 188 that has a filter 182, a throttle 184, and a normally open electromagnetic on-off valve 186 that can adjust the flow rate.
are connected to each other by. The electromagnetic on-off valve 186 is configured to open by energizing the solenoid 190 and changing its excitation current, and to adjust the flow rate of the working fluid passing through the valve. Also, the high pressure flow path 18
R and the low pressure flow path 48R are connected to each other by a flow path 194 having a pilot-operated on-off valve 192 in the middle. The on-off valve 192 takes in the pressure on both sides of the throttle 184 as a pilot pressure, and maintains the closed position 192a when there is no differential pressure on both sides of the throttle 184, and when the pressure on the high pressure flow path 18R side with respect to the throttle 184 is high. The valve is switched to the open position 192b. Thus aperture 1
84, the electromagnetic on-off valve 186 and the on-off valve 192 cooperate with each other to open the high pressure flow path 18R and the low pressure flow path 481? Therefore, a bypass valve 196 is configured that selectively connects the high-pressure flow path 18 and the low-pressure flow path 48 to control the flow rate of the working fluid flowing from the high-pressure flow path to the low-pressure flow path.

Further, in the illustrated embodiment, a pressure sensor 198 is provided in the high-pressure flow path 18R, and the pressure of the working fluid in the high-pressure flow path is detected by the pressure sensor. In addition, pressure sensors 199FR, 199FL, 1991? R,1
99RL is provided, and these pressure sensors control the working fluid chambers 2FR, 2PL, 2RR, 2RL, respectively.
The internal pressure is detected.

The electromagnetic on-off valve 186 and the pressure control valves 32-38 are controlled by an electric control device 200 shown in FIG. Electrical control device 200 includes a microcomputer 202 .

The microcomputer 202 may have a general configuration as shown in FIG. 2, and includes a central processing unit (CPU) 204 and a read-only memory (ROM) 2.
06, random access memory (RAM) 208,
It has an input port device 210 and an output port device 212, which are connected to each other by a bidirectional common bus 214.

The input port device 210 includes a signal indicating the rotation speed N of the engine 14 from the rotation speed sensor 16, a signal indicating the pressure Ps in the high pressure flow path from the pressure sensor 198, and a pressure sensor 199PI.
? , 199PL, 199RR, 199RL respectively, working fluid chambers 2I'R, 2PL, 2R1? .

Pressure P1 in 2RL (1-PR, PL, RR, R
Signal indicating L), ignition switch (IGSW)
A signal indicating whether or not the ignition switch is in the on state from 216, an emergency engine switch (EMSW) 218 provided in the vehicle interior and operated by the vehicle occupant.
A signal indicating whether or not the switch is in the on state, vehicle height sensor 1441'R, 144FL, ] 44RR,
From 144RL, vehicle height H1 (i-PR, RL, RR) of the parts corresponding to the right front wheel, left front wheel, right rear wheel, and left rear wheel, respectively.
SRL) signals are respectively input. The input port device 210 appropriately processes the signals input thereto, and writes the program stored in the ROM 206 to the CPU and RAM 2 according to instructions of u<cpU 204.
The processed signal is output to 08.

The ROM 206 stores the control flow shown in FIG. 3 and the maps shown in FIGS. 4 to 7.

According to instructions from the CPU 204, the output port device 212 outputs a control signal to the electromagnetic on-off valve 186 via a drive circuit 220, and outputs a control signal to the pressure control valves 32-3 via drive circuits 222-228.
8.In detail, variable aperture 54.72.74.76
A control signal is output to the solenoids 58, 78, 80, and 82 of the controller, and the control signal is output to the display 232 via the drive circuit 230.

The operation of the illustrated embodiment will now be described with reference to the flowchart shown in FIG.

Note that the control flow shown in FIG. 3 is started when the ignition switch 216 is closed. In addition, in the flowchart shown in FIG. 3, flag F is related to whether or not there is a failure in any part of the vehicle height adjustment device, and flag 1 is related to whether or not there is a failure in any part of the vehicle height adjustment device. The flag Fe is related to whether or not the engine is in operation, 1 indicates that the engine is in operation, and the flag Fp is the pressure of the working fluid in the high pressure flow path. This relates to whether Ps has ever exceeded the threshold pressure Pc for completely opening the shutoff valves 150 to 156, and 1 indicates that the pressure Ps has exceeded the pressure Pc.
The flag Fs indicates that the standby pressure Pbi (i
-FRs PLSRR%R1,) is related to whether or not it is set, and 1 indicates that the standby pressure is set.

In the first step 10, a main relay (not shown in the figure) is turned on, and after [2], the process proceeds to step 20.

In step 20, the contents stored in the RAM 208 are cleared and all flags are reset to 0, and then the process proceeds to step 3.

In step 30, a signal indicating the rotation speed N of the engine 14 detected by the rotation speed sensor 16, a signal indicating the rotation speed N of the engine 14 detected by the rotation speed sensor 16,
A signal indicating the pressure Ps in the high pressure flow path detected by the pressure sensor 199 PI? , 199FL, 199R
R, 1991? Working fluid chamber 2PR detected by L,
2PI4.2RR, a signal indicating the pressure Pi in 2RL, a signal indicating whether the ignition switch 216 is in the on state, a signal indicating whether the EMSW 218 is in the on state, vehicle height sensors 144FR, 144FL, 144R
A signal indicating the vehicle height H1 detected by R, 144RL is read, and the process then proceeds to step 40.

In step 40, it is determined whether or not the ignition switch is in the off state, and when it is determined that the ignition switch is in the off state, the process proceeds to step 240, where it is determined that the ignition switch is in the on state. When it is determined that this is the case, the process advances to step 50.

In step 50, it is determined whether or not the EMSW is in the on state, and when it is determined that the EMSW is in the on state, the process proceeds to step 220, where it is determined that the EMSW is not in the on state. When the determination has been made, the process advances to step 60.

In step 60, it is determined whether or not the flag Fr is 1, and when it is determined that it is Ff-1, the process proceeds to step 220, and it is determined that it is not Ff-1. If so, proceed to step 70.

In step 70, whether or not the engine is being operated is determined by determining whether the engine rotation speed N detected by the rotation speed sensor 16 and read in step 32 exceeds a predetermined value. A determination is made, and when it is determined that the engine is not being operated, the process proceeds to step 110, and when it is determined that the engine is being operated, the process proceeds to step 80.

Note that whether or not the engine is being operated may be determined by determining whether or not the generated voltage of a generator (not shown in the drawings) driven by the engine is equal to or higher than a predetermined value.

In step 80, the flag Fc is set to 1, and the process from the time when engine operation is started to the time when the standby pressure Pbi of the pressure control valves 32 to 38 is set in step 200, which will be described later. A timer is started for the time Ts, after which step 90 is entered.

In this case, if the flag Fe has already been set to 1, it remains in that state, and if the timer Ts has already been activated, the timer continues counting.

In step 90, the current Ib applied to the solenoid 190 of the ionization on-off valve 186 of the bypass valve 196 is RO.
Based on the map corresponding to the graph shown in FIG. 4 stored in M206, calculation is performed according to Ib-1b+ΔI bs , and the process then proceeds to step 100.

In step 100, the current 1b calculated in step 90 is applied to the solenoid 190 of the electromagnetic on-off valve 186, thereby driving the bypass valve 196 in the closing direction, and then the process proceeds to step 130.

In step 110, the operation of the TS timer is stopped, and the process then proceeds to step 120. In this case, if the Ts timer is not activated, it remains in that state.

In step 120, it is determined whether the flag FQ is 1 or not, and when it is determined that the flag is Fe-1, that is, it is determined that the engine has stopped after being started, step 220 is performed. If it is determined that the engine is not Fe-1, that is, it is determined that the engine has not been started at all, the process advances to step 130.

In step 130, it is determined whether the pressure PS in the high pressure flow path is equal to or higher than the threshold value Pc, and when it is determined that Ps≧Pc is not satisfied, the process proceeds to step 170, where Ps≧ When it is determined that it is Pc, the process advances to step 140.

In step 140, flag Fp is set to 1, and then the process proceeds to step 150.

In step 150, the vehicle height Hi at the position corresponding to each wheel read in step 30 and the reference vehicle height Hoj
Based on the deviation from the vehicle height adjustment amount Δ at the position corresponding to each wheel.
H1 is calculated according to the following formula, and then step]
Proceed to 60.

ΔOld-Old-Hot Note that the calculation of the vehicle height adjustment amount ΔH1 does not form part of the present invention, and therefore the vehicle height adjustment amount may be calculated in other ways.

In step 160, in order to adjust the vehicle height adjustment amount ΔH1 calculated in step 150, the solenoids 58, 78, .
The current If to be applied to 80 and 82 is calculated, and then the process proceeds to step 290.

In step 170, it is determined whether the flag Fp is 1 or not, and it is determined that the flag Fp is Fp-1, that is, the pressure Ps of the working fluid in the high-pressure flow path is equal to or higher than the threshold suppressing pressure Pc. If it is determined that the value has become lower than this after the initial pressure is determined, the process proceeds to step 150, and it is determined that the pressure is not Fp-1, that is, it is determined that the pressure PS has never exceeded the threshold suppression pressure Pc. When this has been performed, the process advances to step 180.

In step 180, it is determined whether the flag Fs is 1, and if it is determined that Fs=1, the process proceeds to step 290, and it is determined that it is not Fs-1. If so, proceed to step 190.

In step 190, it is determined whether the time TS has elapsed or not, and when it is determined that the time Ts has not elapsed, the process proceeds to step 290, where it is determined that the time Ts has elapsed. When this has been performed, the process advances to step 200.

In step 200, the operation of the TS timer is stopped, and the connections between each pressure control valve and the cutoff valve are established based on the map corresponding to the graph shown in FIG. 7 stored in the ROM 206. The pressure of the working fluid in the flow paths 56, 84 to 88 is set to the standby pressure P, that is, the working fluid chambers 2PR, 2P+, detected by the respective corresponding pressure sensors.
2RR, 2R1, the variable throttles 54, 72 of the pressure control valves 32-38 to achieve a pressure substantially equal to the pressure P'i in the pressure control valves 32-38.
The current 1i (+-1'R%I'L, RR, RL) to be energized to the solenoids 58, 78-82 of ~76 is calculated, and then the process proceeds to step 210.

In step 210, flag Fs is set to 1, and then the process proceeds to step 290.

In step 220, the solenoid 190 of the electromagnetic on-off valve 186 of the bypass valve 196 is adjusted based on the map corresponding to the graph shown in FIG. 6 stored in the ROM 206.
The current 1b applied to is Ib-1b −Δ I
be is calculated, and the process then proceeds to step 230.

In step 230, the current Ib calculated in step 220 is applied to the solenoid 190, thereby driving the bypass valve 196 in the opening direction, and then the process proceeds to step 290.

In step 240, as shown in FIG.
Time Tof from when the ignition switch is turned off to when the main relay is turned off
It is determined whether or not the timer related to f is activated, and when it is determined that the Toff timer is activated, the process proceeds to step 260, where it is determined that the Toff timer is not activated. If so, the process advances to step 250.

In step 250, the TOrr timer is started, and the process then proceeds to step 260.

In step 260, the current i applied to the solenoid 190 of the electromagnetic on-off valve 186 is determined based on the seven points corresponding to the graph shown in FIG. 5 stored in the ROM 206.
b is Ib-1b-ΔIb.

After that, the process proceeds to step 270.

In step 270, the current Ib calculated in step 260 is applied to the wire 190 of the electromagnetic on-off valve 186, thereby driving the bypass valve 196 in the opening direction, and then the process proceeds to step 280.

In step 280, it is determined whether the time Tofr has elapsed or not, and when it is determined that the time Torr has elapsed, the process proceeds to step 350, where the time Tofr has elapsed.
If it is determined that the period has not elapsed, the process advances to step 290.

In step 290, step 90, 220.26
It is determined whether the current Ib calculated at 0 is greater than or equal to the reference value Ibo, and Il)≧Ib.

If it is determined that this is not the case, the process proceeds to step 320, and if it is determined that II)≧1110, the process proceeds to step 300.

In step 300, it is determined whether the pressure Ps of the working fluid in the high pressure flow path read in step 30 is greater than or equal to the reference value Pso, and it is determined that Ps≧Pso is not satisfied. When the Ps
When it is determined that ≧Pso, step 3
Proceed to step 10.

In step 310, the current 11 calculated in step 160 is applied to the variable throttle solenoid 5 of each pressure control valve.
8. Each pressure control valve is driven by the output from 78 to 82 to perform small height adjustment, and then step 320
Proceed to.

In step 320, it is determined whether or not there is a fail at any location within the vehicle height adjustment device, and if it is determined that there is no fail, the process proceeds to step 340, where it is determined that there is no fail. If it is determined that the file exists, the process advances to step 330.

In step 330, the fail flag Fr is set to 1, and the process then proceeds to step 340.

At step 340, diagnosis processing is performed for each part in the vehicle height adjustment device, and if an abnormality such as a failure exists, a code number indicating the location is displayed on the display 2.
32, and if there is no abnormality in any part, proceed to step 3 without displaying the code number on the display.
0, and steps 30-340 described above are repeated.

In step 350, the main relay is turned off, thereby ending the control flow shown in FIG. 3 and stopping power to the electric control device 200 shown in FIG. It will be done.

Thus, according to this embodiment, when the vehicle height adjustment device starts operating, a negative determination is first made in steps 40 to 60, and a negative determination is made in step 70 while the engine has not started yet. A determination is made. As shown in FIG. 8, when the engine starts after the time TX elapses from the time when the ignition switch is closed, a YES determination is made in step 70, and two steps are activated. At step 80, the operation of the Ts timer is started, and at step 90, the current 1b is calculated based on a map corresponding to the graph shown in FIG.

As shown in FIGS. 4 and 8, Ib is 0 for a time Tsl from the time the engine starts,
Thereafter, the current Ib is gradually increased over time (Ts2Ts + ) until the current I is sufficient to completely close the bypass valve.

Therefore, the bypass valve is gradually closed after the engine has started and reached a complete explosion state, thereby ensuring that the load on the pump and engine increases rapidly when the vehicle height adjustment device starts operating, ensuring that the engine will either run or stop. can be avoided.

Furthermore, in this case, as mentioned above, when the vehicle height adjustment device starts operating, the bypass valves are gradually opened, thereby gradually increasing the pressure in the high-pressure flow path, and as a result, each cutoff valve is gradually opened. Instead of controlling the standby pressure of each pressure control valve to be substantially equal to the pressure of the working fluid chamber of the corresponding actuator as in the above embodiment, the standby pressure is controlled to a constant value predicted from the vehicle height. Even if there is some pressure difference on both sides of each shutoff valve, as in the case of It is possible to avoid giving a sense of discomfort to

Note that the bypass valve starts to close, and as a result, the high pressure flow path 18
Since the pressure pulsation of the working fluid caused by the pump is relatively high until the pressure in the attenuator increases and the pressure rises to the set pressure of the attenuator, the operation of the current 1b in step 90 is may be calculated according to the pattern shown in broken lines in FIG. That is, as shown in FIG. 8, the current 1b is increased relatively quickly until the current IO reaches the amount by which the bypass valve is closed so that the pressure in the high-pressure flow path 18 becomes the set pressure of the attenuator, and then the current 1b is increased relatively quickly. current 1
b to l! By gently increasing the pressure to 100, it is possible to reduce noise caused by pump discharge pulsation.

Further, when the vehicle height adjustment device normally stops operating due to the completion of driving of the vehicle, a determination is made in step 40, and a determination of no is made in step 240. In step 250, the operation of the Tof'r timer is started, and in step 260, the current Ib is calculated based on a map corresponding to the graph shown in FIG.

As shown in FIGS. 5 and 8, the current Ib is gradually reduced to I2 from the time the ignition switch is turned off until the time Tol has elapsed, and then the current Ib is reduced to I2 (T02Tol). During this time, the current Ib is gradually reduced to 0 relatively quickly, and the main relay is switched off at a time (TorrTo 2 ) after the current Ib becomes 0.

Thus, when the vehicle height adjustment device normally stops operating, the current is 1b.
is gradually reduced, thereby gradually opening the bypass valve, thereby preventing a relatively large amount of working fluid stored in the accumulator from rapidly flowing through the low-pressure flow path or the like.

In addition, if the vehicle occupant senses an abnormality and switches the EMSW on, or if the electric control device detects a failure, a YES determination is made in steps 50 and 60, respectively, and the engine operation is stopped. If the sudden stop occurs, a negative determination is made in step 70, a yes determination is made in step 120, and then, in step 220, a map corresponding to the graph shown in FIG. Based on this, the current 1b is calculated. In this case, as shown in Fig. 6 and Fig. 8, Ib is constant from the time the EMSW is turned on, the time a failure is detected, or the time the engine operation suddenly stops until time TeI. It is reduced relatively quickly to I3 and then tapered to 0.

Therefore, in this case as well, compared to the case where the bypass valve is suddenly opened when the EMSW is switched on, when a fail is detected, or when the engine operation suddenly stops, the accumulator It is possible to prevent a relatively large amount of accumulated working fluid from rapidly flowing through the low-pressure flow path, etc., and to reduce the pressure in the high-pressure flow path relatively at the initial stage of stopping the operation of the vehicle height adjustment device. By quickly reducing the pressure, the shutoff valve can be closed quickly, thereby reducing the possibility of a dangerous situation occurring due to malfunction of the vehicle height adjustment device.

In the above embodiment, the working fluid supply passage means and the working fluid discharge passage means are common between the control valve (pressure control valve) and the working fluid chamber of the actuator; The means may be independent of each other at least in part between the control valve and the actuating fluid chamber.

Furthermore, in the above-mentioned embodiment, the control valve that controls the supply and discharge of the working fluid to and from the working fluid chamber is a pressure control valve, but the control valve has a pressure control valve that controls the supply and discharge of the working fluid to and from the working fluid chamber. The hydraulic circuit of the vehicle height adjustment device of the present invention may be of any structure, and therefore, the hydraulic circuit of the vehicle height adjustment device of the present invention is shown, for example, in FIGS. The circuits shown in FIGS. 7 and 9 may also be used.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. This will be clear to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of a vehicle height adjustment device according to the present invention, FIG. 2 is a block diagram showing an electric control device of the embodiment shown in FIG. 1, and FIG. This figure is a flowchart showing the control flow achieved by the electric control device shown in FIG. Figure 7 is a graph showing a map used when calculating the current Ib supplied to the bypass valve when the operation is stopped in an abnormal situation, and the pressure Pi in the working fluid chamber of each actuator and the current Ib supplied to each pressure control valve. FIG. 8 is a time chart 1 showing the change in the current 1b when the vehicle height adjusting device starts and stops operating. ] 1 liter? , 11'L, 11? l? , 1)iL
...actuator, 2PI? , 2P+4.2R1?
, 21? L... Working fluid ¥, 4... Reserve tank, 6... Pump, 8... Filter, 10... Suction channel, 12... Drain channel, 14... Engine. 16... Rotation speed sensor, ]8... High pressure flow path, 20...
・・Taben, 22・・Attenuator, 24.26・・
・Accumulator, 32.34.36.38...Pressure control valve 40.42.44.46...Switching control valve,
48...Low pressure flow path, 52...Fixed throttle, 54...
riJ strange aperture. 56... Connection flow path, 58... Solenoid, 66.6
8.70...Fixed aperture, 72.74.76...1■
Weird aperture. 78.80.82... Solenoid, 84.86.88
... Connection channel, 110 to 11-8... Drain channel,
120...Filter, 124-130...Aperture, 1
32-138...Accumulator, 1441 CoR,]
44 PL. 144 RRll 44 ML...Vehicle height sensor, 50
~156...Shutoff valve, 166-172...Relief valve, 174...Oil cooler, ]76...Filter, 1
80...Relief valve,]82...Filter, 184
... Throttle, 186... Solenoid on-off valve, IQ (1...
Solenoid, 192...Opening/closing valve, 196...Bypass valve, 198.199...F1, 199P+, 1
99RR, 199R1, ... pressure sensor, 200...
- Electrical control device, 202... microcomputer, 204... CPU, 206... ROM. 208...RAM, 21 (1...person support device,
212... Output boat device, 216... Igni-sotion switch, 218... EMSW, 220-2'
U0...Drive circuit, 232...Display device patent application person Toyota Motor Corporation 1 Doyo
Attorney Patent Attorney Akashi 8 Tsuyoshi

Claims (1)

[Claims] A plurality of actuators are provided corresponding to each wheel of the vehicle and increase or decrease the vehicle height at a position corresponding to each wheel by supplying and discharging a working fluid to and from a working fluid chamber, and a plurality of actuators that increase or decrease the vehicle height at a position corresponding to each wheel; A working fluid supply passage means for supplying working fluid, a working fluid discharge passage means for discharging the working fluid from the working fluid chamber, and selectively communicating and connecting the working fluid supply passage means and the working fluid discharge passage means. a bypass valve; a control valve provided between the bypass valve and the actuator in the middle of the working fluid supply passage means and the working fluid discharge passage means to control supply and discharge of the working fluid to and from the working fluid chamber; A vehicle height adjustment device comprising: a control means for controlling the bypass valve and the control valve, wherein the control means is configured to gradually open the bypass valve when the operation is stopped.