JP2724592B2 - Height adjustment device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height adjustment device which is disposed between a vehicle body and an axle and also serves as a shock absorber for coping with road surface vibration.

[Conventional technology]

As a vehicle height adjusting device which is provided between a vehicle body and an axle and serves also as a shock absorber for coping with road surface vibration, for example, a vehicle having a structure as shown in FIG. 3 has been proposed. I have.

That is, the vehicle height adjusting device includes a vehicle height adjuster 1 also serving as a shock absorber, and a hydraulic circuit 2 that expands and contracts the vehicle height adjuster 1.

The vehicle height adjuster 1 is formed in the form of a so-called hydraulic shock absorber, and inserts a piston rod 12 into and out of a cylinder 11 which is a lower end side, and
A piston portion 13 is provided at the lower end of the cylinder 12 and slides freely in the cylinder 11.

The piston portion 13 defines a rod-side oil chamber A and a piston-side oil chamber B in the cylinder 11, and an oil passage 13a that communicates the rod-side oil chamber A with the piston-side oil chamber B.
And a check valve 13b that allows the hydraulic oil from the piston-side oil chamber B to flow into the rod-side oil chamber A in the oil passage 13a.

The rod side oil chamber A is communicated with an external oil passage 12b through a through hole 12a formed in the piston rod 12, and the piston side oil chamber B is connected through a port 11a formed in the cylinder 11. It communicates with the external oil passage 11b.

Note that a throttle 11c as a telescopic damping valve is provided in the oil passage 11b.

Inside the lower end of the cylinder 11, there is provided a base valve portion 14 which is located in the piston side oil chamber B, and the piston side oil chamber B is connected to the cylinder 11 through the base valve portion 14.
, That is, a reservoir chamber C defined between the outer tube 15 and the outer tube 15.

The base valve section 14 is provided with a check valve 14a and a throttle 14b as a pressure-side damping valve, and hydraulic oil from the reservoir chamber C flows into the piston-side oil chamber B via the check valve 14a. Then, the hydraulic oil from the piston side oil chamber B flows into the reservoir chamber C via the throttle 14b.

The upper part of the reservoir C is a gas chamber D bordering the oil level.
It has been.

The hydraulic circuit 2 includes a bidirectional pump 22 which is rotated in both forward and reverse directions by a driving source 21 driven by a vehicle engine or a battery, and uses hydraulic oil sucked from a tank 23 as pressure oil. It is formed so as to discharge into the oil passage 24 on the vehicle height adjuster 1 side and to discharge pressure oil into the oil passage 24a on the tank 23 side.

The oil passage 24 is connected to the oil passages 12b and 11b via a switching valve 25. The oil passage 24 has a throttle 24b and a check valve 24c parallel to the throttle 24b.

The switching valve 25 has a normal communication position 25b set by the urging force of the spring 25a, and a supply / discharge position 25d that is switched when the solenoid 25c is excited.

When the switching valve 25 is in the communication position 25b, the oil passage 12a and the oil passage 11b are in a communicating state, and when the switching valve 25 is in the supply / discharge position 25d, the oil passage 24 and the oil passage 12a are in communication. Communication is established.

The oil pressure projected from the bidirectional pump 22 into the oil passage 24 is
It is set by the relief valve 22a.

Therefore, in this vehicle height adjusting device, when the switching valve 25 is at the illustrated communication position 25b, the rod-side oil chamber A and the piston-side oil chamber B are communicated via the oil passages 12a and 11b. The piston portion 13 slides freely in the cylinder 11, and at this time, an expansion-side damping force is generated by a throttle 11c disposed in the oil passage 11b, and the base valve portion 14 The pressure-side damping force is generated by the arranged throttle 14b, so that the vehicle height adjuster 1 functions as a hydraulic shock absorber.

Further, for example, when the bidirectional pump 22 is rotated forward to discharge the pressure oil into the oil passage 24, and the solenoid 25c is excited to switch the switching valve 25 to the supply / discharge position 25d, the pressure from the bidirectional pump 22 is increased. Oil flows into the rod-side oil chamber A, and the pressurized oil flows into the rod-side oil chamber A, whereby the piston portion 13 descends in the cylinder 11 and the vehicle height adjuster 1 tends to contract. Therefore, the vehicle height is adjusted so as to decrease the vehicle height.

In the above state, that is, when the switching valve 25 is in the supply / discharge position.
When the two-way pump 22 is reversed in the state switched to 25d, the pressure oil in the rod-side oil chamber A flows out into the tank 23 through the oil passages 24 and 24b. The section 13 is raised, and thus the vehicle height is adjusted to return to the high vehicle height tendency.

[Problems to be solved by the invention]

However, in the above-described conventional apparatus, when the vehicle height is adjusted to be lowered, the vehicle height adjuster 1 has a hydraulic cylinder shape, and the suspension spring is also compressed to be in a state close to a rigid body. If the vehicle is driven in such a state, there are inconveniences such as significantly degrading the running stability of the vehicle and damaging the vehicle.

Therefore, when the vehicle starts traveling, it is necessary to return to a high vehicle height, but the above-described conventional device does not take such consideration into consideration, and even if the vehicle starts traveling at a low vehicle height, No consideration has been given to automatically returning to a high vehicle height.

Further, in the above-described conventional apparatus, when the vehicle driving engine is stopped, the driving source 21 must be driven by the battery to operate the bidirectional pump 22, and in this case, the battery is insufficiently charged. Was invited,
There is a fear that the driving engine cannot be started.

Furthermore, in the above-described conventional apparatus, the adjustment of the vehicle height depends on the driver's intuition, visual recognition from the outside of the vehicle, and the like.

In view of the above-mentioned circumstances, the present invention enables not only accurate vehicle height adjustment with simple operation, but also desired vehicle height adjustment even when the vehicle is stopped, and also enables the vehicle to start traveling. It is an object of the present invention to provide a vehicle height adjusting device that is sometimes automatically returned to a predetermined vehicle height.

[Means for solving the problem]

In order to achieve the above object, a configuration of a vehicle height adjusting device according to the present invention includes a vehicle height adjuster which is provided between a vehicle body side and an axle side and also serves as a shock absorber, and supplies and discharges pressure oil by a hydraulic circuit. In a vehicle height adjusting device formed so as to be able to expand and contract by control to adjust the vehicle height, a vehicle height adjuster is used when pressure oil flows into a rod side oil chamber defined by a piston portion in a cylinder. It contracts and is formed so as to freely expand and contract when the piston-side oil chamber and the rod-side oil chamber are defined by the piston portion in the cylinder, and the hydraulic circuit is driven by an appropriate drive source. A two-way pump that discharges pressure oil in both forward and reverse directions, and is switched by the supply oil pressure from the two-way pump to allow the pressure oil from the two-way pump to flow into the rod-side oil chamber and release the supply oil pressure. A pilot switching valve for communicating the said piston-side oil chamber and the rod side oil chamber is returned to,
An operating check valve that permits free flow of the pressure oil from the bidirectional pump to the rod-side oil chamber but prevents backflow thereof, and a pressure switch that detects oil pressure in the hydraulic circuit. A control mechanism is connected to the appropriate drive source, the control mechanism includes a controller connected to the pressure switch and an appropriate drive source, and an engine rotation sensor and a transmission sensor connected to the controller. A vehicle speed sensor or a vehicle condition detection means comprising a brake sensor, etc., and an operation panel which is provided in the vehicle, is equipped with a vehicle height raising switch, a vehicle height lowering switch, and an error indicator light and is connected together with the controller, It is characterized by having.

(Operation)

Therefore, the bidirectional pump is supplied, for example, to the rod-side oil chamber in the vehicle height adjuster via the operating check valve and the pilot switching valve switched to the supply / discharge position by rotating the bidirectional pump forward. Then, the vehicle height adjuster is contracted to adjust the vehicle height to a low vehicle height tendency.

When the vehicle height adjuster enters a predetermined contracted state, the pressure state at this time is detected by the pressure switch, and the rotation of the bidirectional pump is stopped, though via the controller.

When the rotation of the bidirectional pump is stopped, the supply of the pressure oil from the bidirectional pump is stopped.At this time, the operating check valve functions as a check valve, and the pilot switching valve is maintained at the supply / discharge position. The pressure oil from the rod-side oil chamber does not flow out to the tank side, and the low vehicle height state of the vehicle is maintained.

Conversely, when the bidirectional pump is reversed and the hydraulic oil from the bidirectional pump is discharged to the tank, the pilot pressure is guided, the operating check valve is opened, and the rod side is driven by the suspension spring force of the vehicle. The pressure oil from the oil chamber is discharged to the tank side via the opened operation check valve, the vehicle height adjuster is extended, and the vehicle height tends to be high, that is, the return is adjusted.

Further, when the oil pressure in the rod-side oil chamber decreases, the pilot switching valve is returned to the communication position, and at this time, the pressure state when the vehicle height adjuster is in the predetermined extended state is detected by the pressure switch. The rotation of the bidirectional pump is stopped through the controller, and the operation check valve functions as a check valve to prevent the pressure oil from flowing out of the rod-side oil chamber. It can expand and contract as it is, and functions as a hydraulic shock absorber.

Each of the forward and reverse rotation operations of the bidirectional pump is enabled via a controller by a so-called switch operation to each of the vehicle height raising and vehicle lowering switches on the operation panel,
The operation of the switch is appropriately controlled with the assistance of a vehicle condition detecting means connected to the controller for inputting the vehicle condition and a pressure switch for inputting the pressure condition of the hydraulic circuit, so that at least the vehicle is driven by the engine. When traveling, a required high vehicle height state is automatically secured regardless of whether or not the vehicle height raising switch is operated.

Further, when the vehicle stops running and the engine is not running, the bidirectional pump is not operated to rotate even if a so-called switch operation is performed, so that shortage of battery charge is not caused.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to one illustrated preferred embodiment.

As shown in FIG. 1, a vehicle height adjusting device according to the present invention is provided between a vehicle body side and an axle side, and is connected to the vehicle height adjuster 1 also serving as a shock absorber. And a control mechanism 3 for controlling the hydraulic circuit 2.

The vehicle height adjuster 1 is a conventional vehicle height adjuster 1 described above.
(See FIG. 3).
Since there is no difference in the present invention, only the reference numerals are used in the drawings, and a detailed description thereof will be omitted.

The hydraulic circuit 2 is driven in either the forward or reverse direction by an appropriate drive source 21 and discharges hydraulic oil in both directions.
22.

The appropriate drive source 21 is formed so as to be driven by a vehicle engine or a battery to drive the bidirectional pump 22.

For example, the bidirectional pump 22 is provided with a check valve
The hydraulic oil sucked up from the tank 23 through the oil passage 22b is discharged into the oil passage 24 as pressure oil, and the hydraulic oil sucked up from the tank 23 through the check valve 22c at the time of the reverse rotation is also discharged into the oil passage 24. Is discharged into the oil passage 24a.

The oil pressure projected from the bidirectional pump 22 into the oil passage 24 is
It is set by the relief valve 22a.

Also, a throttle 24d is provided in the oil passage 22a, and when pressure oil is discharged from the bidirectional pump 22 to the oil passage 24a, a predetermined oil pressure is set up in the oil passage 24a. Have been.

The oil passage 24 is connected to a pilot switching valve 26.

The pilot switching valve 26 has a communication position 26b set by the urging force of the spring 26, and a supply / discharge position 26d switched at the time of supplying hydraulic pressure to the pilot passage 26c.

The pilot switching valve 26 is connected to the communication position 26.
b, communication between the oil passage 12b and the oil passage 11b of the vehicle height adjuster 1 is enabled, and when the supply / discharge position 26d is switched, the oil passage 12b and the oil passage 24 are connected. .

The oil passage 24 has a throttle 24b and a check valve 24c in parallel with the throttle 24b, a pressure switch 27, and an operation check valve 2.
Eight are arranged.

The throttle 24b controls the outflow speed of hydraulic oil flowing out from the oil passage 12b, that is, the rod-side oil chamber A toward the bidirectional pump 22, and the pressure switch 27 detects the oil pressure in the oil passage 24, This is input to a controller 31 constituting the control mechanism 3 described later.

The operation check valve 28 is provided between the check valve 24c and the bidirectional pump 22, and is formed so that a pilot passage 28a thereof is connected to the oil passage 24a.

Therefore, the operation check valve 28 is a two-way pump.
For example, when the pressure oil 22 is rotated forward and discharges the pressure oil into the oil passage 24 which is the vehicle height adjuster 1 side, the flow of the pressure oil to the so-called supply side is allowed, but the reverse flow thereof is prevented. Functions as a valve.

Then, when the bidirectional pump 22 is rotated in the reverse direction and discharges the pressure oil to the oil passage 24a corresponding to the tank 23, the hydraulic pressure rises in the oil passage 24a due to the interposition of the throttle 24d provided in the oil passage 24a. Accordingly, the hydraulic pressure acts on the operation check valve 28 through the pilot passage 28a, and the operation check valve 28
Is opened, and in particular, the pressure oil from the vehicle height adjuster 1 side is allowed to flow into the tank 23.

Therefore, when the bi-directional pump 22 is driven, for example, to rotate forward and the pressure oil is discharged into the oil passage 24, the pressure oil is supplied to the pilot switching valve 26 switched to the supply / discharge position 26d by the supply of the pressure oil. Is supplied into the rod-side oil chamber A in the vehicle height adjuster 1 so that the vehicle height adjuster 1 is contracted.

At this time, the rotation of the bidirectional pump 22 is stopped by an input from the pressure switch 27 (via the controller), and the operation check valve 28 functions as a check valve, which corresponds to the suspension spring force of the vehicle. Pressure is maintained in oil passage 24.

Accordingly, the pilot switching valve 26 is maintained at the supply / discharge position 26d, and the rod-side oil chamber A and the piston-side oil chamber B in the cylinder 11 are kept in a disconnected state. The state is maintained.

Conversely, when the two-way pump 22 is driven to rotate in the reverse direction, pressure oil is discharged into the oil passage 24a,
Since the throttle 24d is interposed in 4a, a hydraulic pressure rises in the oil passage 24a, and the hydraulic pressure acts on the operating check valve 28 via the pilot passage 28a, and the operating check valve
28 is released, so that the pressure oil from the rod-side oil chamber A flows out to the tank 23 via the oil passage 24, and the vehicle height adjuster 1 is returned to the predetermined extended state.

At this time, the pilot switching valve 26 is returned to and maintained in the communication position 26b due to a decrease in the pressure in the oil passage 24, and the rod-side oil chamber A and the piston-side oil chamber B in the cylinder 11 are in a communication state.

At this time, the rotation of the bidirectional pump 22 is stopped by an input from the pressure switch 27 (via the controller), the operation check valve 28 returns to the original check valve state, and the pressure from the rod-side oil chamber A is reduced. Oil is prevented from flowing out, and the vehicle height adjuster 1 freely expands and contracts under a predetermined extended state, and functions as a so-called hydraulic shock absorber.

The above-described operation of raising and lowering the vehicle height is performed by appropriately driving the bidirectional pump 22 in either the forward or reverse direction.
This is realized by control of the control mechanism 3 with respect to 21.

Therefore, the control mechanism 3 includes a controller 31 for controlling the driving of the drive source 21, a vehicle condition detecting means 32 connected to the controller 31, and an operation mounted in the vehicle so as to be connected together with the controller 31. And a board 33.

The controller 31 receives a signal from the pressure switch 27 as described above, and the pressure switch 27 detects the height of the vehicle. Will be.

Although the controller 31 is directly connected to the drive source 21 in the figure, the drive source 21 is shown as being driven by an engine or a battery or the like for running the vehicle. However, it is connected to a driving device disposed between the driving engine and the battery.

The operation panel 33 includes a vehicle height lowering switch 33a, a vehicle height raising switch 33b, and an error indicator light 33c.

The vehicle height lowering switch 33a is a switch operated when the vehicle height is desired to be lowered, the vehicle height raising switch 33b is a switch operated when the vehicle height is desired to be increased, and the error indicator light 33c is as described above. This is a warning light when the switch operation is a so-called erroneous operation.

In the present embodiment, the vehicle height lowering switch 33a is turned on when the vehicle height is in the low vehicle height state, as well as when the vehicle height lowering switch 33a and the vehicle height raising switch 33b are operated. State, and when the vehicle height is in the high vehicle height state, the vehicle height raising switch 33b is in a lighting state, and furthermore, each of the vehicle height raising and lowering is blinking during each operation of the vehicle height lowering or raising. Is formed.

In this embodiment, the vehicle condition detection means 32 includes an engine rotation sensor 32a, a transmission sensor 32b, a vehicle speed sensor 32c, and a brake sensor 32d.

The engine rotation sensor 32a detects that the engine is rotating, the transmission sensor 32b detects that the transmission is in a so-called driving position for moving the vehicle forward or backward, and the vehicle speed sensor 32c
At least detects that the vehicle is moving, and of course when the vehicle is running on the engine,
This is also detected in the case of so-called hill start, and the brake sensor 32
d detects that the side brake is in operation when the side brake in the vehicle is operated.

In this embodiment, at least the vehicle speed sensor 32
c, or when the transmission sensor 32b is inputting a detection signal to the controller 31, that is, when the vehicle is running even if the vehicle starts on a slope, the vehicle height is lowered even if the vehicle height lowering switch 33a is operated. The vehicle height is automatically adjusted to the high vehicle height trend without being adjusted to the vehicle height trend, and even if the instruction to increase the vehicle height is not actively given.

This is to prevent the vehicle height from staying in the low vehicle height state and to return the vehicle height to the high vehicle height state as long as the stopped vehicle travels. This is to give priority.

Accordingly, it is assumed that the side brake operation is prioritized when the vehicle stops, and that the vehicle height reduction switch 33a can be operated to adjust the vehicle height to a low vehicle height when the detection signal from the brake sensor 32d is input to the controller 31. Is also good.

Further, instead of the above, the transmission sensor 32b
If the detection signal is input to the controller 31, it may not be possible to adjust the vehicle height reduction even if the vehicle height reduction switch 33a is operated.

In the present embodiment, the engine rotation sensor 32
If the detection signal from a is not input to the controller 31, no so-called switch operation can make any vehicle height adjustment.

As a result, the drive source 21 is not driven by the battery that is not charged due to the rotation of the bidirectional pump 22, so that the battery is insufficiently charged and the vehicle driving engine is not driven. Can be prevented in advance.

The control of the apparatus of the present invention by the control mechanism 3 formed as described above is a control method based on a flowchart as shown in FIGS. 2 (a) and 2 (b).

In the flowcharts shown in FIGS. 2 (a) and 2 (b), and in FIG. 2 (a) are respectively connected to and in FIG. 2 (b).

In addition, DW is a vehicle height reduction switch, DS is a vehicle height reduction switch 33a, EG
Is the driving engine, SB is the side brake, TM is the transmission, UP is the vehicle height increase, US is the vehicle height increase switch 33b
Is shown.

First, when lowering the vehicle height, the vehicle height lowering switch 33a is turned on.

At this time, when the driving engine of the vehicle is not rotating, the detection signal from the engine rotation sensor 32a is not input to the controller 31, so that the vehicle height lowering operation is not realized, and the error indicator light 33c of the operation panel 33 Lights up.

Similarly, when there is an input from the vehicle speed sensor 32c, when there is an input from the transmission sensor 32b, and when there is no input from the brake sensor 32d, the error indicator light 33c is turned on, and the vehicle height lowering operation is performed. Not expressed.

When the traveling engine of the vehicle is rotated, a detection signal from the engine rotation sensor 32a is input to the controller 31,
The vehicle height can be adjusted by turning on the vehicle height lowering switch 33a again.

When the vehicle height lowering switch 33a is turned on, the vehicle height lowering operation starts. However, while the vehicle height lowering operation is in progress, the vehicle height lowering switch 33a flashes to warn the vehicle not to run.

When the vehicle height reduction adjustment is completed (by input from the pressure switch 27), the vehicle height reduction switch 33a is turned on.

Next, when the vehicle height is to be adjusted, the vehicle height raising switch 33b is turned on.

At this time, when the driving engine of the vehicle is not rotating, the detection signal from the engine rotation sensor 32a is not input to the controller 31, so that the vehicle height raising operation is not performed, and the operation panel 33 displays an error indicator light. 33c lights up.

Similarly, even when there is no input from the brake sensor 32d, the error indicator light 33c is turned on, and the vehicle height raising operation is not performed.

When the traveling engine of the vehicle is rotated, a detection signal from the engine rotation sensor 32a is input to the controller 31,
When the vehicle height raising switch 33b is turned on again, the vehicle height can be adjusted.

When the vehicle height raising switch 33b is turned on, the vehicle height raising operation is started. However, while the vehicle height raising operation is in progress, the vehicle height raising switch 33b flashes, and a warning is issued so as to refrain from starting running of the vehicle during that time. I do.

When the height adjustment of the vehicle height is completed (by input from the pressure switch 27), the vehicle height raising switch 33b is turned on.

The above is the basic operation of lowering the vehicle height and raising the vehicle height. The following operations are also performed.

That is, first, when the driving of the engine is stopped during the operation of lowering the vehicle height, the signal from the engine rotation sensor 32a is not input to the controller 31, and the vehicle height lowering operation is interrupted. The machine is stopped.

Also, if the side brake is released during the vehicle height lowering operation, a signal from the rake sensor 32d is sent to the controller 31.
Is stopped, the vehicle height lowering operation is interrupted, and the vehicle is stopped at the vehicle height at that time.

When the transmission is driven forward and backward during the vehicle height lowering operation, the transmission sensor
A signal from 32b is input to the controller 31, and the vehicle height is automatically returned to a high vehicle height.

Note that as long as the signal from the transmission sensor 32b is input to the controller 31, the vehicle automatically returns to a high vehicle height even when the engine driving is stopped.

Further, when the vehicle starts running during the vehicle height lowering operation, a signal from the vehicle speed sensor 32c is input to the controller 31, and the vehicle height is automatically returned to the high vehicle height.

At this time, as long as the signal from the vehicle speed sensor 32c is input, the vehicle is automatically returned to a high vehicle height even when the engine driving is stopped.

Next, when the transmission is driven forward and backward when the vehicle is in a low vehicle height state, the transmission sensor
A signal from 32b is input to the controller 31, and the vehicle height is automatically returned to a high vehicle height irrespective of engine driving.

When the vehicle starts running, a signal from the vehicle speed sensor 32c is input to the controller 31, and the vehicle height is automatically returned to a high vehicle height regardless of engine driving.

If the initial operation condition is satisfied, the vehicle height raising operation is continued until a predetermined high vehicle height state is reached.

〔The invention's effect〕

As described above, according to the present invention, the vehicle height can be freely adjusted to either the high vehicle height tendency or the low vehicle height tendency by selecting either forward rotation or reverse rotation of the bidirectional pump. Particularly, when the vehicle height adjuster is in the extended state, there is an advantage that the vehicle height adjuster can also function as a hydraulic shock absorber.

Further, according to the present invention, each of the forward and reverse rotation operations of the bidirectional pump is enabled via a controller by a so-called switch operation to each of the vehicle height raising and vehicle lowering switches on the operation panel, and the switches are operated by the switches. The operation is appropriately controlled with the aid of a vehicle situation detecting means connected to the controller and inputting the situation of the vehicle. Particularly, as long as the vehicle is in a running state due to starting on a slope, as well as when the vehicle is driven by an engine. There is an advantage that a required high vehicle height state is automatically secured regardless of whether or not the vehicle height raising switch is operated.

Further, according to the present invention, when the vehicle stops running and the engine is not rotating, the bidirectional pump is not rotated even if a so-called switch operation is performed, and therefore, there is an advantage that a shortage of power storage of the battery does not occur. .

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a vehicle height adjusting device according to the present invention, and FIG.
FIGS. 2 (a) and 2 (b) are flowcharts showing the operation procedure, and FIG. 3 is a circuit diagram showing a vehicle height adjusting device as a conventional example. [Explanation of Signs] 1 ... Height Adjuster 2 ... Hydraulic Circuit 3 ... Control Mechanism 11 ... Cylinder 13 ... Piston 21 ... Driving Source 22 ... Bidirectional Pump 26 ... Pilot Switching Valve 27 ... Pressure switch 28 Operate check valve 31 Controller 32 Vehicle condition detecting means 32a Engine rotation sensor 32b Transmission sensor 32c Vehicle speed sensor 32d Brake sensor 33 Operation panel 33a Vehicle height Lower switch 33b… Height raising switch 33c …… Error indicator light A …… Rod side oil chamber B …… Piston side oil chamber

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Shiro 2548 Tsuchida, Kani City, Gifu Prefecture Kayaba Industrial Co., Ltd. Gifu North Plant (56) References JP-A-61-244613 (JP, A)

Claims (1)

(57) [Claims] 1. A vehicle height adjuster which is provided between a vehicle body side and an axle side and also serves as a shock absorber is formed so as to be able to adjust a vehicle height by expanding and contracting by controlling supply and discharge of pressure oil by a hydraulic circuit. In the vehicle height adjusting device, the vehicle height adjuster contracts when pressure oil flows into the rod-side oil chamber defined by the piston in the cylinder, and is defined by the piston in the cylinder. A two-way pump that is formed so as to freely expand and contract when the piston-side oil chamber communicates with the rod-side oil chamber, and the hydraulic circuit is driven by an appropriate drive source to discharge pressure oil in both forward and reverse directions. And the pressure oil from the two-way pump is switched by the supply oil pressure from the two-way pump to flow into the rod-side oil chamber, and is returned when the supply oil pressure is released to return to the piston-side oil chamber and the rod-side oil chamber. When A pilot switching valve for communicating,
An operating check valve that permits free flow of the pressure oil from the bidirectional pump to the rod-side oil chamber but prevents backflow thereof, and a pressure switch that detects oil pressure in the hydraulic circuit. A control mechanism is connected to the appropriate drive source, the control mechanism includes a controller connected to the pressure switch and an appropriate drive source, and an engine rotation sensor and a transmission sensor connected to the controller. A vehicle speed sensor or a vehicle condition detection means comprising a brake sensor, etc., and an operation panel which is provided in the vehicle, is equipped with a vehicle height raising switch, a vehicle height lowering switch, and an error indicator light and is connected together with the controller, Height adjusting device characterized by having