JPH10306837A - Car height regulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the car height of a vehicle under running at a constant value through self-pumping operation, to smoothly realize car height increase operation through operation of a pumping mechanism, and to regulate the car height to a proper value through external operation even when the car height of a vehicle under a stop is lowered due to the increase of a loaded load. SOLUTION: A pump chamber P to form a pumping mechanism to effect self-pumping operation incorporated in an expansion body 1 according to expansion and contraction according to relative vertical movement of the car body of a vehicle forms the expansion body 1 through a discharge valve 21. A check valve C is provided to be communicated with an oil chamber (a piston lower chamber R2) forming the reaction force source of the expansion body 1 through a flow passage L and allow the passage of oil from the pump chamber P to a flow passage L but block the reverse flow thereof. Further, an accumulator A is connected between the check valve C in the flow passage L and the discharge valve 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height adjustment which enables a self-pumping operation to maintain an appropriate vehicle height in a running vehicle and also enables an external operation to adjust a vehicle height in a stopped vehicle. It relates to improvement of the device.

[0002]

2. Description of the Related Art Conventionally, a self-pumping operation has been known as a vehicle height adjustment device which enables a vehicle to be maintained at a proper height while a vehicle is stopped by an external operation. There are various proposals. For example, in the proposal disclosed in Japanese Patent Laid-Open No. 7-174181,
It has the following configuration.

That is, in this conventional vehicle height adjusting device, a telescopic body arranged between the vehicle body side and the axle side of the vehicle and expanding and contracting in accordance with the relative vertical movement of the vehicle body has a self-pumping action. While maintaining a constant expansion / contraction state, that is, while being set to maintain a constant vehicle height, the hydraulic chamber on the high-pressure side serving as a reaction force source when the pumping mechanism of the expansion / contraction body that performs a self-pumping operation is activated. A normal check switching valve having a check valve that is connected to a low pressure side chamber serving as a reservoir through a passage having a normally closed on-off valve and that allows a passage of oil from a hydraulic chamber but prevents a reverse flow thereof. It is said that it is connected to an accumulator through a passage.

[0004] First, a pumping mechanism for realizing a self-pumping function will be described. First, a cylinder which constitutes a telescopic body and serves as a vehicle-body-side member, and which also serves as an axle-side member and is slidable in the cylinder via a piston. It is configured in connection with a hollow piston rod to be inserted.

That is, this pumping mechanism is such that a hollow pump rod is inserted from the upper end of the pump cylinder into a pump cylinder inserted into the hollow piston rod with a gap, and the pump is inserted into the lower end of the pump cylinder. The pump chamber is partitioned, and the pump chamber is communicated with the hydraulic chamber through the discharge valve and the clearance provided at the lower end of the pump cylinder, and the suction chamber and the pump are arranged at the lower end of the pump rod. It is described that the low-pressure chamber is connected to the low-pressure chamber through a passage in the rod.

On the other hand, in this pumping mechanism, a leveling port is formed at an intermediate portion of the pump rod to enable communication between a hydraulic chamber and a passage in the pump rod. When the hydraulic chamber is opened apart from the inner periphery of the upper end, the hydraulic chamber is communicated with the chamber, and the pumping operation is stopped.

Further, in this pumping mechanism,
The inside of the cylinder is divided into an upper piston chamber and a lower piston chamber by a piston connected to a hollow piston rod, and both the upper piston chamber and the lower piston chamber are set in the above-described hydraulic chamber and are arranged on the piston. The upper piston chamber is set as the main hydraulic chamber, assuming that the upper piston chamber can be communicated with the other via the existing damping valve and that the pressure receiving area of the upper piston chamber exceeds the pressure receiving area of the lower piston chamber.

Therefore, according to this conventional vehicle height adjusting device, the vehicle height of the running vehicle is maintained at a constant vehicle height by the self-pumping action of the pumping mechanism, and the vehicle is stopped by an external operation. The height of the vehicle can be adjusted to a low height.

That is, by opening and closing an open / close valve in a passage connecting the high pressure side hydraulic chamber and the low pressure side chamber by an external operation, oil from the hydraulic chamber is released to the chamber and the elastic body is compressed. As a result, it is possible to lower the vehicle height of the vehicle in which the telescopic body is interposed, to a desired low vehicle height state, and to facilitate loading and unloading of a load and getting on and off of a person.

[0010]

However, it has been pointed out that the above-mentioned conventional vehicle height adjusting device has the following disadvantages.

That is, when the pumping mechanism operates by the expansion and contraction of the expandable body, oil from the pump chamber is discharged to the hydraulic chamber and oil from the hydraulic chamber is discharged to the accumulator. Since the discharge amount is determined by the cross-sectional area of the pump rod and the discharge amount from the hydraulic chamber is determined by the cross-sectional area of the piston rod, and the cross-sectional area of the piston rod is greater than the cross-sectional area of the pump rod. The extension operation is performed by the pumping action accompanying the operation.

Therefore, in the vehicle, when the body is lowered by compression of the expandable body, the body tends to rise by expansion of the expandable body due to the pumping action.
There is a concern that the vehicle height may increase while the vehicle body moves up and down, and there is a concern that the accumulation of pressure in the accumulator may not be quickly realized.

Next, when the pumping mechanism operates, the oil discharged from the pump chamber is once discharged to the hydraulic chamber and then to the accumulator. Therefore, the internal pressure in the accumulator is based on the hydraulic pressure in the hydraulic chamber. Therefore, it cannot be set to greatly exceed the hydraulic pressure in the hydraulic chamber.

When the vehicle is running empty or running on a good road, the pumping mechanism hardly operates even if the telescopic member expands and contracts, so that the oil is supplied to the accumulator. That is, a moderate pressure accumulation is not realized.

As a result, the accumulator is, for example,
Even if a large amount of oil is allowed to flow in when a running vehicle rides on a bump on the road, for example, if the vehicle height is reduced due to an increase in the loading load while the vehicle is stopped, a so-called low vehicle Even if the height of the vehicle in the high state is increased to prevent so-called belly running during traveling, this cannot be realized.

That is, even if the switching valve in the passage connecting the hydraulic chamber and the accumulator is switched while the on-off valve is closed to supply the oil of the accumulator to the hydraulic chamber, the accumulator does not have a sufficient pressure accumulation.
It can be said that adjustment to the desired high vehicle height state becomes impossible.

In order to increase the vehicle height, it is necessary to increase the diameter of the accumulator in order to increase the cross-sectional area. In order to realize the operation, the diameters of cylinders, piston rods, and related members such as pump cylinders and pump rods are increased, and as a result, it is unreasonable to cause so-called itachi.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to maintain the vehicle height of a running vehicle at a constant height by self-pumping. In addition to smoothly realizing the vehicle height raising operation by the operation of the pumping mechanism, even if the vehicle height of a stopped vehicle decreases due to an increase in the load, etc., it is necessary to ensure that the vehicle height is properly adjusted by external operation. It is to provide a vehicle height adjustment device that is optimal to make it possible.

[0019]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the structure of the present invention is basically changed between a vehicle body side and an axle side of a vehicle so that the vehicle body can move up and down relatively. A pump body that has a pumping mechanism that has a pumping mechanism that performs a self-pumping action when it expands and contracts, and an accumulator that communicates with a pumping mechanism that is built into the telescopic body, and that forms a pumping mechanism. In a vehicle height adjusting device which is communicated with an accumulator via a discharge valve, a pump chamber constitutes a telescopic body, and is capable of communicating with a hydraulic chamber serving as a reaction force source in the telescopic body via a flow path, and a flow path. It is assumed that a check valve that allows the passage of oil from the pump chamber but prevents the backflow is provided, and that an accumulator is connected between the check valve and the discharge valve in the flow path. .

More specifically, a pumping mechanism constitutes a telescopic body and serves as an axle side member, and a pumping mechanism constitutes an extendable body and serves as a vehicle body side member. A hollow piston rod inserted at the lower end so that the piston that separates the upper and lower chambers of the piston as a chamber is inserted at the lower end so that the lower end side can protrude and retract into the cylinder, and is inserted with a gap into the hollow piston rod. A pump cylinder which forms a cylindrical passage between the piston cylinder and the piston rod, and a hollow cylinder which is inserted into the pump cylinder to define a pump chamber in the pump cylinder and has an internal passage communicating with a chamber on the low pressure side. A pump rod, the upstream end of the flow path being connected to the pump chamber via the upper end of the hollow piston rod, and the hollow piston rod and the pump cylinder being connected to each other. The downstream end of the flow path is connected to the cylindrical passage, and the discharge valve is disposed at the upper end of the pump cylinder. The inner peripheral side of the pump cylinder and the cylindrical passage are connected to the lower end of the pump cylinder. An opening for communication is opened, a suction valve is arranged at the upper end of the pump rod, and the outer periphery of an intermediate portion of the pump rod can communicate with the lower piston chamber of the cylindrical passage through the opening. And a leveling port for communicating the outer peripheral side of the pump rod with the internal passage is formed in the upper end of the pump rod.

Preferably, the check valve disposed in the flow path is incorporated in a switching valve which is switched to an open position by an external operation. Further, the check valve is connected to the flow path and connected to the accumulator. A normal check switching valve that switches to the open position by external operation is provided, and the check position of this switching valve is set to allow oil to pass from the pump chamber but prevent oil from passing from the accumulator. Suppose you have been.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiment. As shown in FIG. 1, a vehicle height adjusting apparatus according to an embodiment of the present invention A pumping mechanism is disposed between a vehicle body (not shown) side and an axle (not shown) side of the vehicle body (not shown), and expands and contracts in accordance with the relative vertical movement of the vehicle body, and performs a self-pumping function when expanding and contracting. It has an elastic body 1 and an accumulator A communicating with a pumping mechanism built in the elastic body 1, and a pump chamber P constituting the pumping mechanism is connected to the accumulator A via a discharge valve 21. And

The pump chamber P constitutes the expansion and contraction body 1 and can communicate with the hydraulic chamber serving as a reaction force source in the expansion and contraction body 1 through the flow path L. Has a check valve C that allows the passage of the check valve C but prevents the reverse flow.
It is assumed that an accumulator A is connected between the accumulator A and the control unit 1.

First, the telescopic body 1 includes a cylinder 11 serving as an axle side member and a cylinder
A hollow piston rod 13 which is inserted into the cylinder 1 and is slidably housed in a cylinder 11 at the lower end thereof and holds a piston 12 defining an upper piston chamber R1 and a lower piston chamber R2 as a hydraulic chamber; Outer cylinder 1 which is arranged on the outer peripheral side of the cylinder 11 and forms a cylindrical chamber with the cylinder 11
4 and is formed in the form of a multi-cylinder type hydraulic shock absorber.

That is, the telescopic body 1 is
And a damping valve 12a.
a, the pressure-receiving area of the piston lower chamber R2 is greater than the pressure-receiving area of the piston upper chamber R1, while allowing the upper piston chamber R1 and the lower piston chamber R2 to communicate with each other with the generation of damping force. The lower piston chamber R2 is set as a main hydraulic chamber serving as a reaction force source in the telescopic body 1.

The telescopic body 1 seals the lower end of the cylinder 11 with a bottom block 15, and connects the piston lower chamber R2 to the cylinder 11 and the outer cylinder 14 through a port 15a opened in the bottom block 15. And communicate with the above-mentioned cylindrical chamber formed between them.

This cylindrical chamber is used as a reservoir chamber in a multi-cylinder hydraulic shock absorber. In the illustrated embodiment, a high-pressure side hydraulic chamber communicating with the piston lower chamber R2 is provided. It has a chamber and a low-pressure side chamber as a reservoir for storing oil sucked into the pump chamber P of the pumping mechanism.

The high pressure side chamber as a hydraulic chamber formed in this cylindrical chamber has a lower end held on the outer periphery on the lower end side of the bottom block 15 and the inner periphery thereof and the cylinder 1.
1 and a bladder 17 fixed to the inner periphery of the outer cylinder 14 by the retainer 16.

Then, the space between the bladder 17 and the outer cylinder 14 is set to a sealed gas chamber G, and the space between the retainer 16 and the bladder 17 is set to an oil chamber R3. This oil chamber R3 is opened to the bottom block 15. It communicates with a lower piston chamber R2 as a main hydraulic chamber through a bore port 15a.

Further, the low pressure side chamber as a reservoir formed in the cylindrical chamber is formed in the upper half of the cylindrical chamber, and the gas chamber G1 bordering the oil surface O is formed. The low pressure side chamber is provided with a gap formed between the retainer 16 and the cylinder 11 and the bottom block 1.
5 is connected to a pumping mechanism described later via an opening 15b.

Incidentally, the lower end of the outer cylinder 14 is sealed by a bottom member 18 carrying a bottom block 15, and the upper end of the outer cylinder closes the upper end of the cylinder 11 and a shaft sealing member 19 through which the piston rod 13 is inserted. It is sealed with.

In the telescopic body 1 according to this embodiment formed as described above, the piston 12 is
At the time of the compression operation that descends inside, the oil in the lower piston chamber R2 flows into the upper piston chamber R1 via the damping valve 12a disposed in the piston 12, and also corresponds to the invading rod volume that becomes excessive in the lower piston chamber R2. Amount of oil is
Oil chamber R, which is a high pressure side chamber formed between
Flow into 3

When the piston 12 extends in the cylinder 11, the oil in the upper piston chamber R1 flows out to the lower piston chamber R2 via the damping valve 12a disposed in the piston 12, and the lower piston chamber R1 is released. Oil is supplied from the oil chamber R3 in an amount corresponding to the withdrawal rod volume that becomes insufficient in R2.

As a result, when the expandable body 1 expands and contracts, a predetermined amount of damping force is generated by passing the oil through the damping valve 12a, and the oil flows into and out of the oil chamber R3. The gas spring effect can be expected to be exhibited.

Next, the pumping mechanism is constructed in connection with the cylinder 11 and the hollow piston rod 13. In the embodiment shown in the drawings, the pumping mechanism includes the cylinder 11 and the hollow piston rod 13. In addition, a pump cylinder 22 and a hollow pump rod 23 are provided.

To explain a little, the pump cylinder 22 is
Inserted into the hollow piston rod 13 with a gap to form a cylindrical passage 13a with the piston rod 13;
A discharge valve 21 composed of a check valve is arranged inside the upper end.

The lower end of the pump cylinder 22 is sealed between the lower end of the hollow piston rod 13 and the cylindrical passage 13a from the lower piston chamber R2. The cylindrical passage 13a communicates with the inner peripheral side of the pump cylinder 22 through the opening 22a.

The lower end of the hollow pump rod 23 is connected to the upper end axis of the bottom block 15 so that the cylinder 1
The upper end is inserted into a pump cylinder 22 to define a pump chamber P in the pump cylinder 22 and an internal passage 23a is formed in the bottom block 15 through a port 15b formed in the bottom block 15. To communicate with the chamber on the low pressure side.

In the pump rod 23, a suction valve 24 composed of a check valve facing the pump chamber P is disposed at the upper end, and a cylinder through the opening 22a is provided on the outer periphery of the intermediate portion. And a leveling port 2 for communicating the outer peripheral side of the pump rod 23 with the internal passage 23a at the upper end side.
3c is said to be opened.

In the pumping mechanism formed as described above, the upper end of the hollow piston rod 13 is connected to the upstream end of the flow path L, and the upper end of the hollow piston rod 13 is It is assumed that the downstream end of the flow path L is connected.

The check valve C disposed in the flow path L
Is configured to be incorporated in a switching valve in the illustrated embodiment, and this switching valve is formed in a mode having a check position 31 having a check valve C and an open position 32. It is set to switch to the open position 32 by an external operation such as input of, and to switch to the check position 31 by an operation to release the excitation signal.

The check valve C in the check position 31 is a so-called back-up, and is a relief valve which is not opened unless the pressure from the pump chamber P becomes higher than a lower piston chamber R2 as a main hydraulic chamber by a certain value or more. It is also set to work.

Since the accumulator A has a well-known structure, a detailed description thereof will be omitted.

Therefore, in the pumping mechanism according to this embodiment formed as described above, when the hollow piston rod 13 is immersed in the cylinder 11 by the compression operation of the expansion and contraction body 1, The hollow pump rod 23 is immersed in the piston rod 13, and at this time, the oil in the pump chamber P is discharged to the flow path L by opening the discharge valve 21.

The oil discharged into the flow path L flows into the accumulator A until the pressure exceeds the check position 31 of the switching valve, that is, the set pressure of the check valve C.
When the pressure exceeds the set pressure of the check valve C, the cylindrical passage 13 a formed on the inner peripheral side of the hollow piston rod 13, the opening 22 a formed in the pump cylinder 22 and the pump rod 23 Passage 2 formed on the outer circumference
The fluid flows into the lower piston chamber R2 as a main hydraulic chamber in the cylinder 11 via 3b.

However, at this time, as described above, the hollow piston rod 1
3, the excess oil in the lower piston chamber R2 flows into the hydraulic chamber outside the cylinder 11, and the pressure in the lower piston chamber R2 is higher than the pressure before the hollow piston rod 13 enters. The action of closing the check valve C occurs.

For this reason, most of the oil discharged from the pump chamber P flows into the accumulator A, so that a desired pressure accumulation in the accumulator A is realized.

At this time, in this embodiment, the internal pressure in the accumulator A can be set based on the internal pressure in the pump chamber P, that is, the pump chamber P
Lower piston chamber R as a hydraulic chamber with a larger cross-sectional area
2 can be set without involving the internal pressure of the piston 2 and the internal pressure of the lower piston chamber R2 is prevented from reaching the accumulator A by the check valve C. Therefore, the internal pressure of the lower accumulator A is increased by the internal pressure higher than the internal pressure of the lower piston chamber R2. You can do it.

Further, in this embodiment,
The oil discharged from the pump chamber P flows directly into the accumulator A, unlike the above-described conventional example, so that the vehicle height does not tend to decrease and the vehicle height can be increased. Not only does it not move up and down, but also the pressure accumulation in the accumulator A is quickly realized.

On the other hand, when the hollow piston rod 13 comes out of the cylinder 11 by the extension operation of the telescopic body 1, the hollow pump rod 2
At this time, the oil from the low pressure side chamber is supplied to the pump chamber P through the port 15b of the bottom block 15, the passage 23a of the pump rod 23, and the suction valve 24.

At this time, as described above, in the lower piston chamber R2, an insufficient amount of oil is supplied from the oil chamber R3 outside the cylinder 11 due to the retreat of the hollow piston rod 13 in the lower piston chamber R2.

Then, when the hollow pump rod 23 repeatedly comes into and out of the hollow piston rod 13,
Since sufficient oil is accumulated in the accumulator A and the pressure increases, the oil discharged from the pump chamber P cannot flow into the accumulator A, and the check position 31 of the switching valve, that is, the check valve C is pushed. It opens and flows into the lower piston chamber R2 as a hydraulic chamber. At this time, the cylinder reaction force, that is, the rod reaction force is increased and the piston rod 13 tends to protrude from the cylinder 11, and at this time, the vehicle Is adjusted to the appropriate high vehicle height tendency.

The flow of oil into the lower piston chamber R2 is continued, and the hollow pump rod 23 is
3, the communication between the opening 22a in the pump cylinder 22 and the passage 23b on the outer periphery of the pump rod 23 is interrupted, and the leveling port 23c formed in the pump rod 23 The lower end is separated from the inner periphery and opens to the lower piston chamber R2.

In this state, the piston lower chamber R2
Communicates with the reservoir on the low pressure side as a reservoir via the leveling port 23c, the passage 23a in the pump rod 23, and the port 15b of the bottom block 15. In this case, the accumulator A from the pump chamber P
No oil is discharged to the accumulator A, and the so-called return passage formed by the passage 23b, the opening 22a, and the cylindrical passage 13a is also closed between the piston lower chamber R2, which is a hydraulic chamber, and the accumulator A. There will be no inflow.

As a result, the elastic body 1 has a fixed length unless the elastic body 1 and the pump mechanism tend to compress due to so-called oil leakage, and the leveling port 23c is closed by the pump cylinder 22. It expands and contracts in a state, that is, the height position of the vehicle body in the vehicle is kept constant.

On the other hand, when the vehicle is stopped from the above state and the telescopic body 1 cannot be expanded or contracted, for example, when the vehicle height decreases due to an increase in the load or occupants, , To prevent so-called belly running
In other words, it is necessary to increase the vehicle height in a low vehicle height state. At this time, it is sufficient to supply oil from the accumulator A to the lower piston chamber R2 as the main hydraulic chamber.

That is, in this embodiment, the leveling port 23c is, of course, closed by the pump cylinder 22, but the opening 22a formed in the pump cylinder 22 is formed on the outer periphery of the pump rod 23. When the switching valve in the flow path L is switched to the open position 32 by an external operation under the condition that the communication with the passage 23b is established, the oil from the accumulator A causes the cylindrical gap 13a, the opening 22a and the passage 23b Is supplied to the lower piston chamber R2 as a main hydraulic chamber via the hydraulic pump.

Then, when the oil from the accumulator A is supplied to the lower piston chamber R2, the piston 12 rises in the cylinder 11 due to the difference in pressure receiving area between the upper piston chamber R1 and the lower piston chamber R2. The vehicle height of the vehicle is adjusted to a high vehicle height state by the rod reaction force at this time.

In this embodiment, as described above, the internal pressure in the accumulator A can be set higher than the internal pressure in the piston lower chamber R2 as the main hydraulic chamber. Will be realized.

FIG. 2 shows a vehicle height adjusting apparatus according to another embodiment of the present invention. In this embodiment, the structure of the elastic body 1 is the same as that of the above-described embodiment. However, in addition to the feature in the height position of the leveling port 23c formed in the pump rod 23 constituting the pumping mechanism, the configuration of the check valve C in the flow path L and an additional switching valve in the flow path L are provided. There is a feature in the point.

Therefore, parts having the same structure including the elastic body 1 are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted except where necessary. Features of the embodiment will be described.

That is, first, regarding the height position of the leveling port 23c formed on the pump rod 23, the height position is closer to the upper end of the pump rod 23 than in the above-described embodiment. Is set.

As a result, while the leveling port 23c is closed, the stroke in which the communication between the opening 22a formed in the pump cylinder 22 and the passage 23b formed on the outer periphery of the pump rod 23 is interrupted becomes longer.

As a result, until this stroke disappears, the oil from the pump chamber P due to the pumping action cannot flow into the lower piston chamber R2 as the hydraulic chamber, and all the oil flows into the accumulator A. Thus, the accumulated pressure in the accumulator A can be made higher than in the above-described embodiment.

During the above stroke, the pump chamber P
Oil flows into accumulator A, so that compared to the case of the above-described embodiment, accumulator A
, The time required for accumulating pressure is greatly reduced.

Next, the check valve C disposed in the flow path L
Is formed in the form of a normal check valve that allows the oil from the accumulator A to pass to the lower piston chamber R2 but prevents the reverse flow.

The accumulator flow path L1 connected to the flow path L in which the check valve C is disposed and connected to the accumulator A is provided with a normal check switching valve. Is set to allow the passage of oil from the pump chamber P but prevent the passage of oil from the accumulator A.

This switching valve is also formed to have an open position 32 in addition to the check position 33. For example, the switching valve is switched to the open position 32 by an external operation such as input of an excitation signal. The setting is such that the operation is switched to the check position 33 when the excitation signal is released.

As described above, the accumulator flow path L1
And the check valve C is disposed in the flow path L, so that the pressure in the lower piston chamber R2 is prevented from reaching the accumulator A side by the check valve C and discharged from the pump chamber P. Oil flows into the accumulator A.

In addition, the oil discharged from the pump chamber P flows into the lower piston chamber R2 via the check valve C, and increases the pressure in the lower piston chamber R2 to extend the telescopic body 1.

At this time, in this embodiment, the check valve C does not need the action of a relief valve as in the embodiment shown in FIG. However, as compared with the case of the embodiment shown in FIG. 1 described above, the pressure becomes equal to and lower than that of the piston lower chamber R2. This is advantageous in that the comfort is not deteriorated.

As described above, the extendable body 1 constituting the vehicle height adjusting device according to the present invention is disposed between the vehicle body side and the axle side of the vehicle, and expands and contracts according to the relative vertical movement of the vehicle body. A pumping mechanism that performs a self-pumping action is set therein, which is separate from a hydraulic shock absorber (shock absorber) that constitutes a suspension in each of the left and right wheel portions of the vehicle as in the above-described conventional example. It can be freely set to the vehicle height adjustment unit or to the hydraulic shock absorbers constituting the suspensions at the left and right wheel portions of the vehicle.

However, when this vehicle height adjusting device is set in a hydraulic shock absorber that constitutes a suspension in each of the left and right wheel portions of the vehicle, at least the above-mentioned so-called separately placed situation does not occur, so that the vehicle height adjusting device is not used. This is advantageous in that the number of parts can be reduced.

[0074]

As described above, according to the present invention, the vehicle height of the running vehicle can be maintained at a constant height by the self-pumping action of the pumping mechanism. The internal pressure in the accumulator can be set based on the internal pressure in the pump chamber instead of the hydraulic chamber, and since the internal pressure in the hydraulic chamber is prevented from reaching the accumulator by the check valve, the accumulator can be stored at an internal pressure higher than the internal pressure in the hydraulic chamber. Become.

At this time, since the oil discharged from the pump chamber flows directly into the accumulator, the vehicle height does not tend to decrease and the vehicle height can be increased, and the vehicle body does not move up and down. Needless to say, the accumulation of pressure in the accumulator will be realized quickly, especially when the vehicle is leveling to maintain the vehicle height at a constant height, and the so-called return that allows the hydraulic pressure from the pump chamber to flow into the hydraulic chamber. If the interval between when the flow path is closed is set to be long, pressure accumulation in the accumulator can be realized more quickly.

Since the accumulated pressure in the accumulator is higher than that in the hydraulic chamber, the switching valve in the flow path connecting the accumulator and the hydraulic chamber is opened by an external operation, whereby the hydraulic chamber of the oil from the accumulator is opened. , The vehicle height raising operation of extending the telescopic body is realized.

As a result, according to the present invention, not only the vehicle height of the running vehicle is maintained at a constant height by the self-pumping action, but also the vehicle height raising operation by the operation of the pumping mechanism is smoothly realized. In addition, there is an advantage that even when the vehicle height of the stopped vehicle decreases due to an increase in the load, the vehicle height can be reliably adjusted to an appropriate vehicle height by an external operation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view partially showing a circuit diagram of a vehicle height adjusting apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a vehicle height adjusting device according to another embodiment of the present invention, similarly to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Telescopic body 11 Cylinder 12 Piston 13 Hollow piston rod 13a Cylindrical passage 14 Outer cylinder 21 Discharge valve 22 Pump cylinder 22a Opening 23 Hollow pump rod 23a, 23b Passage 23c Leveling port 24 Suction valve 32 Open position A Accumulator C Check valve L Flow path L1 Accumulator flow path P Pump chamber R1 Upper piston chamber R2 Lower piston chamber as main hydraulic chamber

Claims (4)

[Claims] 1. A telescopic body having a built-in pumping mechanism disposed between a vehicle body side and an axle side of a vehicle to expand and contract in accordance with the relative vertical movement of the vehicle body and to perform a self-pumping operation when expanding and contracting. An accumulator communicating with a built-in pumping mechanism is provided, and a pump chamber constituting the pumping mechanism is communicated with the accumulator via a discharge valve. The hydraulic chamber, which serves as a reaction force source in the telescopic body, can communicate with the hydraulic chamber via a flow path, and the flow path has a check valve that allows the passage of oil from the pump chamber but prevents the backflow thereof, and An accumulator is connected between the check valve and the discharge valve in the flow path. 2. A piston upper chamber as a hydraulic chamber, wherein the pumping mechanism constitutes a telescopic body and serves as an axle-side member, and a cylinder constitutes an expandable body and serves as a vehicle body-side member and is slidably housed in the cylinder. A hollow piston rod inserted at the lower end thereof so as to be able to protrude and retract into the cylinder while holding the piston defining the lower piston chamber at the lower end, and a piston rod inserted with a gap into the hollow piston rod and A pump cylinder that forms a cylindrical passage between the pump cylinder and a hollow pump rod that is inserted into the pump cylinder to define a pump chamber in the pump cylinder and has an internal passage that communicates with a low-pressure side chamber. The upstream end of the flow path is connected to the pump chamber via the upper end of the hollow piston rod, and the lower end of the flow path is connected to a cylindrical passage between the hollow piston rod and the pump cylinder. The flow end is connected, a discharge valve is arranged at the upper end of the pump cylinder, and an opening for communicating the inner peripheral side of the pump cylinder with the cylindrical passage is opened at the lower end of the pump cylinder. A suction valve is disposed at an upper end of the pump rod, and a passage is formed on an outer periphery of an intermediate portion of the pump rod to enable communication of the cylindrical passage to the lower piston chamber through the opening. 2. The vehicle height adjusting device according to claim 1, wherein a leveling port for communicating an outer peripheral side of the pump rod and an internal passage is opened at an upper end side of the pump rod. 3. The vehicle height adjusting device according to claim 1, wherein a check valve disposed in the flow passage is incorporated in a switching valve that is switched to an open position by an external operation. 4. An accumulator flow path connected to the flow path and connected to the accumulator is provided with a normal check switching valve which is switched to an open position by an external operation. 2. The vehicle height adjusting device according to claim 1, wherein the vehicle height adjusting device is set so as to allow the passage of the oil but prevent the passage of the oil from the accumulator.