JPH04108019A - Electronically controlled fluid pressure suspension - Google Patents

Abstract

PURPOSE:To level the floor surface and to enhance the maneuverability by delivering an instruction signal for a vehicle height adjustment in a designated direction, to a change-over mechanism corresponding to a designated wheel position so as to control the mechanism when a stopping condition is determined. CONSTITUTION:Fluid pressure actuators 100 disposed each between a vehicle body and wheels are connected to a fluid pressure source 101 by way of passages in which change-over mechanisms 102 for blocking fluid chambers in the fluid actuators 100 or for communicating the same with the discharge or drain sides of the fluid pressure source 101 are disposed respectively. Further, a direction indicator 103 indicates whether the direction in which vehicle height adjustment is carried out is upward or downward is indicated by a direction indicator 103, and the position or the positions of a wheel or adjacent two wheels to be subjected to adjustment for the vehicle height are indicated by a position indicator 104. Further, a stopping determining means 105 determines a stopping condition. When the stopping condition is determined, a vehicle height change instructing means 106 delivers an instruction signal corresponding to the indicated direction of the vehicle height adjustment to one of the change- over means 102 which corresponds to the indicated wheel position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a system in which a fluid pressure actuator such as a hydraulic cylinder is individually interposed between a vehicle body and each wheel, and working fluid in the fluid pressure actuator is supplied and discharged. In particular, the present invention relates to an electronically controlled hydraulic suspension capable of adjusting vehicle height.

[Conventional technology]

Hitherto, suspensions equipped with various vehicle height adjustment devices have been used.
A suspension described in Japanese Patent No. 261512 is known.

The conventional suspension described in this publication lowers the vehicle height by exhausting air from the air chamber of the suspension control device when the actual vehicle height value detected by each vehicle height sensor is higher than the target vehicle height range for multiple wheel positions. On the other hand, when the actual vehicle height is lower than the target vehicle height range, the compressor is driven or air is supplied from the reservoir tank to the air chamber to raise the vehicle height, thereby constantly maintaining the actual vehicle height at multiple wheel positions. , so that the vehicle height falls within the target vehicle height range.

However, such conventional vehicle height adjustment devices only control actuators such as air chambers so that the vehicle body is parallel to the road surface, and when the vehicle is stopped on an inclined surface such as a slope or shoulder, The vehicle body floor surface is parallel to the inclined surface. This is not necessarily a convenient vehicle posture when sleeping or working inside the vehicle, for example.

Therefore, a vehicle height adjustment device can be considered that can make the floor surface horizontal in absolute space or adjust it to any angle when the vehicle is stopped. This vehicle height adjustment device includes, for example, a joystick as an indicator that can be operated by a passenger when the vehicle is stopped.

This joystick outputs a signal corresponding to the position of a single wheel (for example, front left side) or multiple wheels (front wheel side, front right side, front right side) for which vehicle height adjustment is desired according to its operation, and receives this signal. The control means supplies and discharges working fluid to and from the fluid chamber at the designated wheel position, so the vehicle height at the desired wheel position is raised or lowered, thereby making it possible to correct the inclination of the vehicle body by manual operation. This is called ``4-axle vehicle height control'').

[Problem B to be Solved by the Invention] When performing such four-axle vehicle height control, it is also necessary to instruct whether to raise or lower the vehicle height. To deal with this, a configuration is usually adopted in which two joystick indicators are installed, one for up and one for down, but as a matter of course, their external forms are very similar. Therefore, it is easy for the occupants to misunderstand the situation, and there is a risk that, for example, the driver may mistakenly perform a down operation when turning on the amplifier, causing interference between the vehicle body and a bump on the road. Furthermore, providing two joysticks of the same type increases the cost.

The present invention was made in view of the unsolved problems of the prior art, and the problem to be solved is to make the floor plane horizontal in absolute space or adjust it to an arbitrary angle. In addition, the purpose is to clarify the manual operation of the amplifier and down in four-axle vehicle height control without increasing costs, and to minimize the room for erroneous operation.

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim (1), as shown in FIG. An actuator 100, a fluid pressure n, 101 connected to each fluid pressure actuator 100 via a flow path, and a fluid pressure n, 101 that is individually inserted in the flow path corresponding to each fluid pressure actuator 100 and responsive to a command signal. A switching mechanism 102 that seals the fluid chamber of the fluid pressure actuator 100 or communicates with the discharge side or the drain side of the fluid pressure source 101 according to the vehicle height is provided, and the vehicle height is adjusted in the up direction or the down direction. a direction indicator 103 that manually indicates the position of one wheel or two adjacent wheels for which vehicle height adjustment is to be performed, a position indicator 104 that manually indicates the position of one wheel or two adjacent wheels for vehicle height adjustment, a stop judgment means 105 that judges the stop state, and a stop judgment means 105 that judges the stop state. Means 10
5, when the stopped state is determined, a command signal corresponding to the vehicle height adjustment direction indicated by the direction indicator 103 is sent to the switching mechanism 102 corresponding to the wheel position indicated by the position indicator 104. and a vehicle height change command means 106 for outputting the vehicle height change command.

Furthermore, in the invention described in claim (2), among the components described in claim (1), each of the switching mechanisms 102 is located downstream of the discharge side of the fluid pressure source 101, as shown in FIG. 1(b). It is equipped with an unload valve that opens and closes in response to a command signal, and a switching valve that is inserted between the unload valve and each of the fluid pressure actuators 100 and opens and closes in response to a command signal. When the stop state is determined by the stop judgment means 105 and the vehicle height up direction is instructed by the direction indicator 103, the change command means 106 instructs the unload valve to close the valve. The device outputs a corresponding command signal, and then outputs a command signal corresponding to the open state of the switching valve to the switching valve.

[Function] In the electronically controlled fluid pressure suspension of the present invention, for example, when the stop state means 105 is determining the stop state, the direction indicator 103 indicates the vehicle height deviation, and the position indicator 104 indicates the vehicle height is increased. Assume that the two front wheels of the vehicle are designated as the desired wheel positions. As a result, the position indicator 104
The vehicle height change command means 106 outputs a vehicle height up command signal designated by the direction indicator 103 to the two switching mechanisms 102 corresponding to the front two wheel positions designated by the vehicle height change command means 106. , the fluid chamber of the fluid pressure actuator 100 at the front two wheel position and the discharge side of the fluid pressure source 101 are communicated with each other. As a result, the working fluid is supplied to the fluid chamber, the actuator 100 is extended, and the vehicle height at the two front wheels is increased.

Therefore, when the vehicle height of the front two wheels reaches a desired value and the vehicle height increase instruction is stopped, the vehicle height change command means 106 stops outputting a signal to the switching mechanism 102. by this,
Since the switching mechanisms 102 for the two front wheels seal the fluid chambers of the corresponding hydraulic actuators 100 to confine the working fluid, the vehicle body maintains the desired tilted posture.

On the other hand, when you want to lower the vehicle height, turn indicator 103
By setting the indicated direction to the down side, the vehicle height value at the front two wheel positions decreases in the same way as described above.

This raising and lowering of the vehicle height can be done in the same way at other two wheel positions (for example, right side, rear side, left side of the vehicle body) or any one wheel position by changing the operation position of the lever etc. of the position indicator 104. . In this vehicle height control operation, whether to raise or lower the vehicle height is determined by the direction indicator 103, which has a separate form from the position indicator 104. Compared to the case where the amp and the down are installed together, there are definitely fewer erroneous operations such as mixing up the amp and down.

Further, according to the electronically controlled fluid pressure suspension according to claim (2), when it is determined that the vehicle is stopped, the direction indicator 103 instructs the direction to raise the vehicle height, with the same effect as described above. In this case, the vehicle height change command means 106
The unload valve is initially set to the closed state. As a result, the working fluid that had been flowing to the tank side of the fluid pressure source 101 is supplied to the switching valve first, and the switching valve enters a standby state. Thereafter, by opening the switching valve, there is no time delay in supplying the working fluid compared to the case where the unload valve is closed and the switching valve is opened at the same time, and the vehicle height can be increased. Wasted time is eliminated.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 to 7 of the accompanying drawings.
This will be explained based on the diagram. This embodiment is a full hydropneumatic suspension that does not have an auxiliary spring such as a metal spring, and receives the load by the force generated by a fluid pressure cylinder.

In Figure 2, 2FL to 2RR are the front passenger to the rear right wheel,
4 indicates a wheel side member, 6 indicates a vehicle body side member, and 8 indicates an electronically controlled hydraulic suspension (electronically controlled hydraulic suspension).

The electronically controlled hydraulic suspension 8 includes a hydraulic pump 10 and an oil tank 12 that serve as a hydraulic source as a fluid pressure source, and an accumulator 14 disposed on the load side of the hydraulic source.
Check valve 16. Hydraulic source side oil passage opening/closing part 18 and front wheel side,
Rear wheel side oil passage opening/closing part 20F, 2OR, and each wheel 2FL to 2R
Suspension characteristic variable mechanism 22FL installed for each R
~22RR, hydraulic cylinders 24FL~24RR as fluid pressure actuators, up/down switch 25A for four-axis vehicle height control, joystick switch 25B, parking switch 25C, vehicle height sensors 26FL~26RR, and acceleration sensor. 28. and a sensor group including a vehicle speed sensor 29, and a controller 30 for arithmetic processing.

Of these, the hydraulic pump 10 is configured as a tandem type pump that rotates using the vehicle engine as a driving source and discharges hydraulic pressure to the power steering device and the hydraulic suspension 8. The suction side of this hydraulic pump 10 is connected to the oil tank 12 by a pipe 31, and the discharge side thereof is connected to a pipe 32. The load side of this piping 32 is communicated with an accumulator 14 for absorbing pulsation, and is also connected to an oil passage opening/closing section 18 on the oil pressure source side via a check valve I6.

This oil passage opening/closing part 18 includes an electromagnetically operated unload valve 34.
, a relief valve 36 with a predetermined relief pressure, and a flow divider 38 that distributes the oil passage between the front and rear wheels. It communicates with each boat on the oil pressure source side of the relief valve 36 and the flow divider 38.

The unload valve 34 has a normally open structure that assumes a communicating position when the control signal S supplied to the electromagnetic solenoid is off, and assumes a blocking position when the control signal S1 is on. Tank side boats of the unload valve 34 and the relief valve 36 are connected to the oil tank 12 by a pipe 40. A filter 42 for filtration is installed in the middle of the pipe 40.
is inserted. Pipes 32F and 32R are connected to two ports on the load side of the flow divider 38, respectively.
F and 32R are front wheel side and rear wheel side oil passage opening/closing parts 20F.

20R, respectively.

The front wheel side oil passage opening/closing section 20F is equipped with a flow divider 42F whose input port is connected to the piping 32F at a position on the oil pressure source side, and flow restriction type check valves 44FL, 44FR, and electromagnetically operated check valves 44FL and 44FR are installed on the load side of the flow divider 42F. Type 2 boat switching valve 46FL, 46FR, 48F, and relief valve 50
It is equipped with FL and 50FR. To elaborate on this,
The two load-side boats of the flow divider 42F are connected to one end of piping 32FL and 32PR corresponding to the front right wheel side, respectively. Among these, the other end of the front left wheel side piping 32F is connected to another switching valve 48 via a check valve 44FL and a switching valve 46FL.
It communicates with one port of F and the high pressure side boat of the relief valve 50FL, and also leads to the suspension characteristic variable mechanism 22FL on the front left wheel side. Similarly, the other end of the front right wheel side piping 32FR is connected to the other port of another switching valve 48F and the relief valve 50 via a check valve 44FR and a switching valve 46FR.
FI? It communicates with the high-pressure side boat, and also leads to the suspension characteristic variable mechanism 22FR on the front left wheel side.

Piping 32FL, 32Fl? Switching valves 46FL, 46FI? are inserted in series with each of ? has a normally closed structure in which a built-in check valve assumes a shutoff position when the control signal S2 supplied to the electromagnetic solenoid is off, and a communication position when the control signal S2 is on. In addition, a switching valve 4 inserted between the pipes 32FL and 32FR
8F also has a control signal S3 supplied to its electromagnetic solenoid.
It has a normally closed structure in which it assumes a shutoff position by a built-in check valve when S is off, and assumes a communicating position when control signal S is on.

Furthermore, the rear wheel side oil passage opening/closing part 2OR also includes a flow divider 42R9, a flow restriction type check valve 44RL, 44RR, and an electromagnetically operated two-boat switching valve 461, which separates the hydraulic oil to the rear left and rear right wheel sides. L, 46RR, 48R1 and relief valve 5
01? L, 50RR, piping 32RL, 32R
[Connected identically to the front wheel side via l. here,
Each of the above-mentioned relief valves 50FL to 50RR prevents an abnormal pressure rise on the load side, and is set to a predetermined relief pressure higher than the normally available pressure range, and the low pressure side boat is connected to the tank 12 by a pipe 52. ing.

Each of the suspension characteristic variable mechanisms 22FL to 22RR has a free piston type first . Second
accumulators 54 and 56, a two-port switching valve 58 for variable spring constant, and a variable throttle 60 for generating damping force. The first accumulator 54 is directly connected to the pipe 32FL, and the second accumulator 54 is directly connected to the pipe 32FL.
6 is connected via the switching valve 58, and the piping 32
A variable aperture 60FL is inserted in series with FL. The switching valve 58 is opened using the motor 58A as an actuator.

The closed position is switched, and the motor 58A is rotated by the drive signal S4. The variable throttle 60 is also energized by the rotation of the motor 60A to adjust the width or narrowness of its flow path, and a drive signal S is supplied to the motor 60A.

Furthermore, each of the hydraulic cylinders 24FL to 24RR has a second
As shown in the figure, the cylinder tube 24a has a pressure chamber separated by a piston 24b. A pipe 32FL (~32RR) is connected to this pressure chamber. In the front wheel side hydraulic cylinders 24FL, 24FR, the cylinder tube 24a is attached to the wheel side member 4, the end of the piston rod 24c is attached to the vehicle body side member 6, and on the contrary, the rear wheel side hydraulic cylinders 24RL, 24RR Here, the cylinder tube 24a is attached to the vehicle body side member 6, and the end of the piston rod 24c is attached to the wheel side member 4.

On the other hand, the amplifier/down switch 25A corresponds to the direction indicator of the present invention, and is composed of a slide switch that takes two indicating positions, up and down, and its output signal UD is "on" when it is in the up position. , is "off" when in the down position, and the joystick
The switch 25B corresponds to the position indicator of the present invention, and the stick 25B automatically returns to the center neutral position N.
a, and can be inserted freely in the radial direction from its neutral position N, and is on the "front side" as shown in FIG.

"Right side J, r rear side", "left side", "front left side".

You can indicate eight directions: r front side J, r rear right side, and rear left side.
J, 'JS3 J, 'JSa J, 'JSs
J, ``JSh J, 'JS? J, 'JSI
A switch signal JS of J can be obtained.

Furthermore, the parking switch 25C has a signal PK that is turned on only when the gear lever is in the parking position.
Output.

Further, the vehicle height sensors 26FL to 26RR are composed of potentiometers and the like, and are attached between the wheel side member 4 and the vehicle body side member 6, and send a vehicle height signal HFL"' Hle+ of a voltage value corresponding to the relative separation amount to the controller 30. The acceleration sensor 28 is installed at a predetermined position on the vehicle body, and outputs a signal G to the controller 30 according to the acceleration in the lateral (vehicle width) direction and longitudinal direction acting on the vehicle body.Vehicle speed sensor 2
9 outputs a signal V corresponding to the vehicle speed to the controller 30 by detecting, for example, the rotational speed of the output shaft of the transmission.

As shown in FIG. 4, the controller 30 includes a gain adjuster 70 that multiplies the input vehicle height detection signal HFL-H□ and acceleration detection signal G by a gain, and an A/D converter that digitizes the output of the gain adjuster 70. A D converter 72, an interface circuit 74 that inputs the vehicle speed detection signal 2 and switch signals tJD, JS, and PK, and a microcomputer that takes in the output signals of the A/D converter 72 and the interface circuit 74 and performs predetermined processing. The computer 76 includes a CPU 76, and a drive circuit 78 that drives each solenoid and motor in accordance with control signals output from the computer 76. The controller 30 includes a timer mechanism that keeps the power on for a predetermined period of time even after the ignition switch is turned off.

The microcomputer 76 inputs the acceleration signal G based on a pre-stored predetermined program, adjusts the rotation of the motor 58A of the switching valve 58 and the motor 60A of the variable throttle 60, and adjusts the spring constant and damping force according to the running condition. At the same time, the vehicle height detection signals HFL to H11m and the vehicle speed signal ■ are input to perform vehicle height control that increases or decreases the average vehicle height.
Four-axle vehicle height control is performed manually based on the process shown in the figure.

Next, the operation of this embodiment will be explained.

First, the flowchart shown in FIGS. 5-6, which is executed by the controller 30, will be explained. The process shown in FIG. 6 is executed as a subroutine during execution of the process shown in FIG. 5, and a typical flow thereof is shown below.

The controller 30 is activated when the ignition switch is turned on, starts the process shown in FIG. 5, and continues the process until the ignition switch is turned off.

When activated, the microcomputer 76 waits until the vehicle is stopped by checking whether the switch signal PK of the parking switch 25C is turned on at step (3) in FIG.

When it is determined in this process that the parking switch 25C is in a stopped state with the parking switch 25C turned on, the process moves to step (3) and the switch signal UD of the up/down switch 25A is
Enter. Thereafter, the process moves to step (2), and it is determined whether or not the vehicle height is increased by checking whether the read signal UD in step (2) is on, which corresponds to increasing the vehicle height. If the result of this judgment is YES, proceed to step (2), turn on the control signal S, and then close the unload valve 34 (blocking position).
When the judgment is j, the process moves to step (2), the control signal S1 is turned off, and the unload valve 34 is opened (
communication position).

When the processing of step ■ or ■ is completed, the process moves to step ■, and the output signal JS of the joystick switch 25B is
After inputting , move to step ■. In step (2), it is determined whether or not the stick 25Ba has been operated by checking whether the read signal in step (2) is JS-OFF corresponding to the neutral position N of the joystick 25B.

If the judgment in step ■ is rNO, it is assumed that the joystick switch 25B has not been operated, and step ■
Return to , but if rYES, continue with steps ■～■
Judgments will be made sequentially. Among these, step■
Based on the read value JS, it is determined whether or not the front side of the vehicle body is commanded to move up or down based on whether JS=JS. When rNOJ is determined in this step (2), it is determined in step (2) whether or not the right side up or down of the vehicle body is commanded based on whether JS=JS.

Similarly, in step [phase] (2), it is determined whether there is a rear side up or down command (JS=JS,) and whether there is a left side amplifier or down command (JS=JS,).

Further, in the case of r N OJ in step ①, it is determined in step @ whether front left up or down (JS=JS,) is commanded. Similarly, step @
~ At @, front cloth side a, 7p or down command (JS=JS
), rear right side up or down command (JS=JS
) is the rear left up or down command (JS=JS
I). And even in step ■, rNO
When it becomes J, it is assumed that the position command is in an idle state and the process returns to step (2).

On the other hand, when rYEsj is determined in steps ■, ■, @, and 0, the process moves to steps ■, ■, and ■ [phase], respectively.
The subroutine processing represented by FIG. 6 is performed.

Among these, the subroutine processing of step [stock] is performed for the front left switching valve 46FL and the front right switching valve 46FR, and the microcomputer 76 executes the subroutine processing in step ① of FIG.
At this time, only the control signals St and Sz for both switching valves 46FL and 46FR are turned on. As a result, both the switching valves 46FL and 46FR are opened, and the cylinder chambers of the front hydraulic cylinders 24FL and 24FR communicate with the hydraulic pressure source.

Next, move to step ■ and joystick/resignal JS
, and then move to step ■.

In this step (2), it is determined whether or not the read value JS of step (2) has changed, and whether or not the stay position of the joystick switch 25B has changed (including the neutral position N). If this judgment is rNOJ, it is assumed that the vehicle front side amplifier or down is continuing and the process returns to Step 7B. rYES'', it is assumed that the operation of raising or lowering the front side of the vehicle body is about to be completed or canceled, and the process then proceeds to step (3).

In step (2), the control signals S, s2 for the front left switching valve 46PL and the front right switching valve 46FR are turned off, thereby closing both the switching valves 46FL and 46FR. For this reason, the front right hydraulic cylinders 24FL, 24
The cylinder chamber of the FR and the hydraulic pressure source are cut off.

Thereafter, the microcomputer 76 returns the process to step (2) in FIG.

Similarly, in the subroutine process of step O in FIG.
The processing for the rear left switching valve 46RL is further performed in step (2).

Processing is performed on the front left switching valve 46FL.

On the other hand, when rYEs is determined in steps @, ■, [phase], and ■, the process moves to steps [phase] and 0, 0°@, respectively, and the subroutine processing represented by FIG. 6 is performed. The subroutine processing of these steps [stock], 0, 0.0 is the aforementioned steps ■, @, @.

Unlike the subroutine processing of [Co., Ltd.], each control controls the opening/closing of only one switching valve. In the processing of step Φ, the front left switching valve 46FL is controlled, and in the processing of step ■, the front right switching valve 46FR is controlled. Now, rear right switching valve 46RR.
1 and step O, the rear left switching valve 46RL is controlled in the same manner as described above.

In this embodiment, the unload valve 34 on the hydraulic power source side and the electromagnetic switching valve 46FL (~46RR) on the load side of each shaft correspond to the switching mechanism for each wheel of the present invention. In addition, parking
The switch 25C and the process of step (2) in FIG. 5 form a stop judgment means, and the interface circuit 74. Fig. 5 Processing of steps ① to [phase].

and a drive circuit 78 form vehicle height change command means.

Next, the overall operation of this embodiment will be explained.

When the vehicle is idling and parking switch 2
When the controller 30 is in a stopped state where 5C is turned on, the controller 30
The microcomputer 76 starts the process shown in FIG. 5.6 related to the four-axle vehicle height control at time t0.

Although the vehicle is currently stopped on a slope and the front side of the vehicle is low, if the occupant does not operate the joystick switch 25B, the microcomputer 76 repeats the processing of steps ■ to ■ in Figure 5 and waits. (Communication valves 48F and 48R are closed). As a result, when the indicated position of the up/down switch 25A is on the up side, the unload valve 34 is in the closed state B (control signal S1: ON), and the discharge pressure of the hydraulic pump 10 is supplied in advance to the switching valves 46FL to 46RR. , the vehicle is in a standby state for raising the vehicle height (see t0 to L1 in FIG. 7). On the other hand, when the pump is on the down side, the unload valve 34 is opened, whereby all the pump discharged oil flows into the tank 12, reducing the consumption flow rate.

In this stopped state, the occupant wants to raise the height of only the front side of the vehicle to take a nearly horizontal vehicle posture in absolute space, and the occupant leaves the amplifier down switch 25A in the up position, and moves the stick 25Ba of the joystick switch 25B to " Insert it into the "front" position. As a result, as described above, the unload valve 34 closes first and enters the standby state, and then the microcomputer 76 shifts the processing from steps ■ to ■ in FIG. Since the control signal S,,S,: is turned on,
The front wheel side switching valves 46FL and 46FR are opened,
Hydraulic oil is supplied to both hydraulic cylinders 24FL and 24FR on the front wheel side. As a result, the vehicle height on the front wheel side increases in proportion to the amount of hydraulic fluid supplied.

Therefore, when the occupant releases the stick 25Ba when the vehicle body is in a nearly horizontal posture, the stick 25Ba automatically returns to its neutral position N. Energized by this, the microcomputer 76 performs steps ■ and ■ in FIG.
Since this process is performed, the switching valves 46FL and 46 on the front wheel side
FR is returned to the closed state, and hydraulic cylinders 24FL and 24P
The R hydraulic oil is sealed and the vehicle height at the time the stick 25Ba is released is maintained.

However, if you want to further correct the tilt of the vehicle (for example, raise it), move the joystick switch 25B to the neutral position N.
All you have to do is reinsert it into the desired position. As a result, the process shown in FIG. 5 is repeated, and if the desired position is, for example, the "left side", the hydraulic cylinders 24FL and 24RL on the front side and the rear left side are activated in the same manner as the above-mentioned "front side". Oil is supplied and only the left side of the car body is lifted up. For example, if it is "front left", the front left hydraulic cylinder 24
Hydraulic oil is supplied only to PL, increasing the vehicle height on the front left side.

On the other hand, if it is desired to lower the vehicle height, the above-described operation may be performed while the up/down switch 25A is slid to the down side. As a result, the unload valve 34
first becomes open, then the corresponding switching valve 46FL~
46RR is opened, the hydraulic oil in the cylinder is discharged, and the vehicle height at the desired position is lowered.

In this way, after stopping on a slope or on the shoulder of the road, the inclination of the vehicle body can be adjusted arbitrarily by manual control, making it easier to take a nap or work inside the vehicle. For this manual operation, a knob down switch 25A and a joystick switch 25B, which have different external forms, are installed, so unlike a case where joystick switches are installed on both the up and down sides, it is possible to raise and lower the vehicle height. This makes it easier to identify, and the functions are differentiated and clarified, ensuring fewer mistakes in up and down operations, resulting in better operability. On the other hand, there is also the advantage that component costs are lower than when a joystick switch is also installed.

Furthermore, in this embodiment, when raising the vehicle height, the contents of the up/down commands are checked first and the unload valve 34 is closed to enter the standby state. [Compared to the case where opening and opening are performed at the same time, the time delay in supplying hydraulic oil to the hydraulic cylinders 24FL to 24RR is reduced. As a result, regardless of the order in which the up/down switch 25A and joystick switch 25B are operated, from the passenger's perspective, it is equivalent to operating the up/down switch 25A first, and when the vehicle height is raised. The total adjustment time is shortened and operational efficiency is improved.

On the other hand, assuming that the ignition switch is in the on state, the controller 30 inputs the detection signal G of the acceleration sensor 28 based on a predetermined program, and when the predetermined roll conditions, acceleration, and deceleration conditions are satisfied, the gas spring constant is large, Controls the electromagnetic switching valve 58 and the variable throttle 60 in the direction of increasing the damping force to suppress changes in the vehicle body posture while driving,
When these conditions are not met, the gas spring constant is small,
Control is performed in the direction of the damping cull to reduce vibrations transmitted from the road surface to the vehicle body, improving ride comfort.

The controller 30 also includes vehicle height sensors 26FL to 26
Based on the detection signal HFL~H~ of the RR, it is determined whether the average vehicle height value deviates from the target vehicle height range, and if the average vehicle height value deviates from the target vehicle height range, the process of raising or lowering the vehicle height is performed, for example, in Japanese Patent Laid-Open No. 6
The method shown in No. 3-154413 (so-called 3-axle vehicle height side m)
This is done using At this time, when raising the vehicle height, the control signal S1 is turned on, the control signal S3 for the front and rear axes is turned on, and each control signal S2 is turned on. As a result, the unload valve 34 is in the closed state, the communication valves 48F and 48R on the front and rear axis are in the open state, and each of the switching valves 46FL to 4 is in the open state.
6RR is opened, and the hydraulic oil discharged from the pump 10 flows into each of the hydraulic cylinders 24FL to 24RR, raising the vehicle height. On the other hand, when lowering the vehicle height, the control signal SI is turned off, the control signal S3 for the front and rear axes is turned on, and each control signal S2 is turned on. As a result, the unload valve 34 is in the open state, the communication valves 48F and 48R on the front and rear axis are in the open state, and each of the switching valves 46FL to 4 is in the open state.
6RR is open, and hydraulic cylinders 24FL to 24R
The R hydraulic oil flows into the tank 12, lowering the vehicle height.

At this time, the target vehicle height value is lowered in high-speed conditions, taking into consideration the vehicle speed value (■).

In addition, although the case where the working fluid is oil has been described in each of the above embodiments, the present invention is not necessarily limited to this, and a gas having a low compressibility may be used.

Further, the fluid pressure actuator of the present invention is not limited to the hydraulic cylinder described in the above-mentioned embodiments, but, for example, as described in Japanese Patent Application Laid-Open No. 63-154413, an air chamber made of an elastic body is provided in the suspension device for each transport. It may also be configured as follows.

Further, the vehicle height change command means of the present invention first controls the switching of the unload valve 34 as described in the above-mentioned embodiment,
Next, the control logic for controlling the switching of the electromagnetic switching valves 46FL to 46RR is not limited to (for example, although the adjustment time when raising the vehicle height is slightly longer, the unloading valve 34 and the electromagnetic switching valves 46FL to 46RR are It is also possible to control switching at the same time.

Furthermore, the switching mechanism of the present invention is not limited to the structure equipped with an unload valve and a 2-point 2-position electromagnetic switching valve as described in the above-mentioned embodiments. Instead, a 3-point, 3-position electromagnetic switching valve may be used that has switching positions for "communicating to the pump side,""cuttingoff," and "communicating to the tank side" depending on whether the control signal is turned on or off. .

〔Effect of the invention〕

As explained above, the present invention includes a direction indicator that manually indicates whether the vehicle height adjustment is to be performed in an up direction or a down direction, and a direction indicator that manually indicates the position of one wheel or two adjacent wheels in which the vehicle height is to be adjusted. A position indicator is provided, and when a stopped state is determined, a command signal in the vehicle height adjustment direction indicated by the direction indicator is output to the switching mechanism corresponding to the wheel position indicated by the position indicator. Since the switching mechanism is controlled by the switch, it is possible to make the floor surface horizontal in absolute space or adjust it to any angle.Furthermore, for example, a joystick switch can be installed on the up side and down side. Compared to the conventional switch structure, the functional differences between the indicators are clear and the external shape is different.
This reduces the possibility of confusing the up side with the down side, and has the effect of reliably improving operability without increasing parts costs.

In addition to the above-mentioned effects, the invention according to claim (2) also has the unique advantage of shortening the total adjustment time when raising the vehicle height.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are claims correspondence diagrams, FIGS. 2 to 7 are diagrams showing an embodiment of the present invention, FIG. 2 is a block diagram showing the overall configuration, and FIG. is an explanatory diagram showing the indicated position of the joystick switch, Figure 4 is a block diagram of the controller, and Figures 5 and 6 are examples of processing procedures for 4-axis vehicle height control executed by the controller in response to manual operations. The schematic flowchart shown in FIG. 7 is a timing chart showing an example of changes in the pump side pressure of the switching valve. In the figure, 100...fluid pressure actuator, 101...
・Fluid pressure source, 102... Switching mechanism, 103... Turn indicator, 104... Position indicator, 105... Stop judgment means, 106... Vehicle height change command means, 4... Wheel side member, 6... Vehicle body side member, 8... Electronically controlled hydraulic suspension, 10... Hydraulic pump, 1
2...Reservoir tank, 24FL~24RR...
Hydraulic cylinder, 25A...up/down switch,
25B...joystick switch, 25C...
・Parking switch, 30...controller, 3
4... Unload valve, 46FL to 46RR... Solenoid switching valve.

Claims (2)

[Claims] (1) A fluid pressure actuator individually interposed between the vehicle body and each wheel, a fluid pressure source connected to each fluid pressure actuator via a flow path, and a fluid pressure source connected to each fluid pressure actuator within the flow path. A switching mechanism that is individually inserted and that seals the fluid chamber of the fluid pressure actuator or connects it to the discharge side or drain side of the fluid pressure source in response to a command signal is provided, and the vehicle height is adjusted. A direction indicator that manually indicates whether the direction is up or down, a position indicator that manually indicates the position of one wheel or two adjacent wheels for vehicle height adjustment, and a stop judgment device that determines whether the vehicle is stopped. and a vehicle height adjustment direction that corresponds to the vehicle height adjustment direction indicated by the direction indicator, to the switching mechanism corresponding to the wheel position indicated by the position indicator when the stopped state is determined by the stop determining means. An electronically controlled fluid pressure suspension comprising: vehicle height change command means for outputting a command signal. (2) Each of the switching mechanisms includes an unload valve that is installed downstream of the discharge side of the fluid pressure source and opens and closes in response to a command signal, and an unload valve that is inserted between the unload valve and each of the fluid pressure actuators. and a switching valve that opens and closes in response to a command signal, and the vehicle height change command means is configured such that when the vehicle stop determination means determines that the vehicle is stopped, the vehicle height change command means commands the vehicle height up direction using the direction indicator. In the case where the unloading valve is closed, the unloading valve outputs a command signal corresponding to the closed state of the valve, and then outputs a command signal corresponding to the open state of the switching valve to the switching valve. The electronically controlled fluid pressure suspension according to claim (1).