JP2926085B2 - Self-pump type vehicle height adjustment device for vehicle hydraulic shock absorber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a self-pump type vehicle height adjusting device for a vehicle hydraulic shock absorber.

[Conventional technology]

The self-pump type vehicle height adjustment device of the vehicle hydraulic shock absorber
For example, it is known from JP-A-58-56985. In this case, the vehicle hydraulic shock absorber to which the self-pump type vehicle height adjustment device is attached has a cylinder having an attachment member at one end, and a piston slidably fitted in the cylinder,
A piston rod protruding from the piston and having a mounting member at a free end, an oil tank connected to an oil chamber between the piston and the cylinder, and a suspension spring stretched between spring supports of the cylinder and the piston rod. It is a rear cushion having. The vehicle height adjusting device provided on the rear cushion includes, as a hydraulic jack portion, a plunger case fixed to a mounting member of the rear cushion, and a plunger slidably fitted on an outer periphery of the plunger case. A hydraulic jack chamber is formed between a spring seat and a plunger case at an inner end of the hydraulic jack. Further, a check valve which is opened at the time of compression and closed at the time of extension is provided at an end of the piston rod in the cylinder, and the check valve and the hydraulic jack chamber are communicated with each other by a long hole provided concentrically with the piston rod. While the motorcycle is running, the check valve opens at the tip of the piston rod during the compression stroke of the rear cushion, and closes during the extension stroke, so that the oil in the pump chamber of the cylinder passes through the long hole in the piston rod and the hydraulic pressure in the plunger case. Flow into jack room.
By this repetition, the oil is guided to the hydraulic jack chamber by the pump action for each compression stroke, the hydraulic jack chamber expands, and the plunger compresses the suspension spring. Since the vehicle body is balanced by the suspension spring, the compression of the suspension spring increases the spring load and pushes up the vehicle body to increase the vehicle height.

[Problems to be solved by the invention]

However, with this self-pump type vehicle height adjustment device, the vehicle height can be kept constant.However, when traveling on rough terrain, the vehicle height is increased to improve the running performance, and when traveling on a flat city area, the rider's foot contact property is improved. I couldn't meet the demand to raise it.

SUMMARY OF THE INVENTION An object of the present invention is to provide a self-pump type vehicle height adjusting device for a vehicle hydraulic shock absorber that can appropriately switch a vehicle height between an up position and a down position in the vicinity of a driver's seat according to a traveling road surface condition. is there.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a rotary switching valve is provided inside, and an oil passage (a) communicating with the pump chamber and an oil passage (b) communicating with the hydraulic jack chamber are provided on the outer periphery of the rotary switching valve. ), A vehicle height adjustment unit having an oil passage (c) communicating with the oil reservoir and a relief oil passage (d) communicating with the oil reservoir via a relief valve is provided. The passages are formed so as to intersect with each other while communicating with each other. One of the oil passages (a) connects an oil passage communicating with the pump chamber and an oil passage communicating with the hydraulic jack chamber when the vehicle height increasing position is set, The oil passage communicating with the oil reservoir and the relief oil passage are connected when the vehicle height down position is set, and the other oil passage (b) is connected to the oil passage communicating with the oil reservoir and the relief oil when the vehicle height up position is set. When connecting the road and setting the vehicle height down position, The oil passage communicating with the pump chamber and the oil passage communicating with the hydraulic jack chamber are connected, and the vehicle height increasing position is set from the intersection of the other oil passage (b) of the rotary switching valve with one oil passage (a). Sometimes, a second check valve is provided on the side opposite to the oil passage communicating with the oil sump chamber in a direction to prevent the flow from the pump chamber to the oil sump chamber, and the hydraulic jack chamber is provided on the oil passage communicating with the hydraulic jack chamber. A first check valve is provided in a direction to prevent the flow from the pump chamber to the pump chamber, and the first check valve is opened when the vehicle height down position of the rotary switching valve is set.

It is convenient if an oil tank having an oil reservoir formed therein is formed separately from the vehicle hydraulic shock absorber, and the oil height tank is provided with this oil tank.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows an overall view of a self-pump type vehicle height adjusting device capable of simultaneously adjusting the vehicle height of a motorcycle rear cushion and front fork, which are hydraulic shock absorbers for a vehicle.

Rear cushion 1 as first vehicle hydraulic shock absorber
Is a cylinder 3 having an axle or vehicle body attachment member 2 at one end, a piston 4 slidably mounted in the cylinder 3, and a piston protruding from the piston to the opposite side of the attachment member 2 and having a free end. A piston rod 6 having an axle or the other mounting member 5 of the vehicle body, and a suspension spring between a spring receiver 7 provided at the piston rod end and a spring receiver 8 provided at the cylinder end. 9 is stretched. The piston 4 is provided with a damping force generator as usual. As is customary, the pump chamber A between the cylinder 3 and the piston 4 of the rear cushion 1 is connected to the oil tank by a pipe 15 extending from a pipe joint 14.
It is connected to a pipe joint 17 which leads to an oil reservoir B of 16. The oil tank 16 has a gas chamber C and an oil storage chamber B separated by a partition wall 18 made of an elastic material.
The pressure is set to about kgf / cm ² .

A well-known jack portion 10, which forms a part of a self-pump type vehicle height adjusting device, has a sleeve 11 fixed to the outer periphery of the cylinder 3 of the rear cushion 1, and a plunger case 12 is fixed to the sleeve. A plunger 13 is slidably mounted between the inner peripheral surface of the case 12 and the outer peripheral surface of the sleeve, and the end of the plunger 13 contacts the suspension spring 9 with the end surface of the spring receiver 8 by pressure. Thus, the hydraulic jack chamber D is formed between the plunger case 12 and the plunger 13.

Front fork 20, the second vehicle hydraulic shock absorber
Is a spring at the upper end of a seat pipe (not shown) which comprises an axle-side outer cylinder 21 and a vehicle-body-side inner cylinder 22 slidable in the axle-side outer cylinder 21 and protrudes upward from the axle-side outer cylinder bottom. A suspension spring 24 is stretched between a support (not shown) and a spring support 23 at the upper end of the vehicle body side inner cylinder 22.

Further, a jack portion 25 of the front fork 20, which forms a part of the self-pump type vehicle height adjusting device, has a plunger case 26 attached to a fork bolt 22a fixed to the upper end of the inner cylinder 22, and a plunger case 26. It comprises a plunger 28 slidably fitted and having a through hole 27, and a rod 29 projecting outward from the plunger.
Thus, a hydraulic jack chamber E is formed between the plunger case 26 and the plunger 28. The spring receiver 23 is attached to the tip of the rod 29.

The vehicle height adjusting section 30 including the rotary switching valve 34 described later according to the present invention includes a pump chamber A of the rear cushion 1, a hydraulic jack chamber D of the jack section 10 of the rear cushion 1, and a hydraulic jack of the jack section 25 of the front fork 20. It is provided in a conduit connecting each to the room E, is provided at the rear lower part of the seat of the motorcycle, and can be operated in the riding posture.

Also, according to the present invention, the oil tank 16
The body 30 is integrally screwed with the main body 31. Body 31
The pipe joint 17 described above is connected to the oil tank via a push-side damping valve 70 (FIG. 5) provided between the oil passages 32 and 33.
It is connected to 16 oil reservoirs B. Since the push-side damping valve itself is a well-known one and does not form a part of the vehicle height adjusting unit 30 of the present invention, a detailed description thereof will be omitted. The push-side damping valve 70 is normally closed, but is opened against the spring by the pressure oil from the pump chamber A during the compression stroke of the rear cushion 1, and when the pump chamber A is depressurized during the extension stroke. It has a built-in valve to open against. The valve opening pressure of the former valve is set higher than the shared load received by the suspension springs 9 and 24 of the rear cushion and the front fork when one rider rides, for example, 30 kg / cm ² .

A rotary switching valve 34 is further rotatably mounted on the main body 31 of the vehicle height adjusting section 30 of the present invention, and the rotary switching valve 34 is located at the vehicle height increasing position shown in FIGS. 1 and 3. And the vehicle height down position shown in FIGS. 2 and 4. The rotary switching valve 34 is
It comprises a rotating shaft 35 and a grip 35 'fixed to the end of the rotating shaft. The rotating shaft 35 has two rows of parallel first and second passages of the same structure which are respectively guided to the hydraulic jack chambers D and E of the jack sections 10 and 25. In FIG. 3, a second check valve 37 urged by a spring 36 in a hole crossing the rotation shaft 35 is disposed in a first passage led to the jack portion 10 of the rear cushion 1. A through passage 38 is arranged orthogonal to the valve. Although not shown, the second passage of the rotary switching valve 34 guided to the jack portion 25 of the front fork 20 also has a spring 38 'and a second check valve.
37 '(FIG. 2) and a through passage 38' are provided. In the first passage of the rotary switching valve 34, the side of the rear cushion 1 toward the pump chamber A is connected to the oil passage 32 via the oil passage 39,
The second passage is connected to the oil passage 32 via the oil passages 40, 41, and 39.

Further, the side of the rotary switching valve 34 toward the jack portions 10 and 25 of the first passage and the second passage is a tappet 4 respectively.
First check valve 43, 43 'via 2, 42' (FIG. 6)
It is connected to the. The first check valves 43, 43 '
The oil passages connecting the pump chamber A of the rear cushion 1 and the jack sections 10 and 25 are respectively formed from the hydraulic jack chamber side by springs 45 and 45 'inserted into holes of bolts 44 and 44' screwed into the main body 31, respectively. It is urged to shut off the return of oil to the pump chamber A side. Pipe fitting 46 around bolt 44
Is connected to a port 48 of the plunger case 12 which opens into the hydraulic jack chamber D of the jack portion 10 of the rear cushion 1 via a pipe 47, while a pipe joint 46 'around the bolt 44' is connected to the front via a pipe 49. The fork 20 is connected to a port 50 that opens to the hydraulic jack chamber E of the jack portion 25 of the fork 20.

The tappets 42 and 42 'described above have a through hole 51 along the axis and a flat surface 52 along the surface in parallel with the through hole 51, as can be clearly seen from FIG. This flat surface is connected to the through hole 51 via the horizontal hole 53. On the other hand, the rotary shaft 35 of the rotary switching valve 34 has
Notch surfaces 35a, 35a 'orthogonal to 8' are formed. 1 and 3, the first check valves 43, 43 'are seated on their valve seats to shut off the oil passage, and the tappets 42, 42' are connected to the rotary switch valve 34. The cut surfaces 35a and 35a 'are in contact with each other. FIG. 2 and FIG.
In the vehicle height down switching position shown in the figure, the first check valves 43, 43 'are pushed by the tappets 42, 42' abutting on the peripheral surface of the rotary shaft 35 of the rotary switching valve 34, and are separated from the valve seats. Hydraulic jack chambers D and E of parts 10 and 25 are provided with flat surfaces 52 and 52 ', tap holes 53 and 53' of tappets 42 and 42 ', respectively.
The rotary switching valves 34, 34 'communicate with the second check valves 37, 37' through the through holes 51, 51 '.

When the internal pressure of the hydraulic jack chambers D and E of the jack sections 10 and 25 becomes equal to or higher than a predetermined value when the vehicle height is increased (FIG. 3), oil sent from the pump chamber A of the rear cushion 1 is removed. In order to return to the oil reservoir B of the oil tank 16, a relief valve 60 (FIGS. 3 and 4) connects the jack portions of the rear cushion 1 and the front fork 20 to the pump chamber A of the rear cushion 1, respectively. It is provided in each of the flow paths branched from the two oil passages and communicating with the oil reservoir B. That is, the relief valve 60 is provided with a cylinder bore provided in the main body 31.
A valve body 62 is slidably inserted into the valve body 61, and a spring 63 biases the valve body toward the oil reservoir B of the oil tank 16. The valve body 62 has a flange portion 62a on the end side facing the spring 63, and an oil chamber F is formed between the large-diameter cylinder hole 61 and the end face of the flange portion 62a. Parts 10, 25
The oil chamber G is connected between the small-diameter cylinder hole 61 'and the distal end face of the valve body 62 opposite to the piston portion.
The oil chamber G is connected to the oil reservoir B of the oil tank 16 via the relief flow path 65, and is connected to the rotary switching valve 34 via the relief flow path 66.

In order to generate a damping force in the compression stroke of the rear cushion 1 when the vehicle is traveling on a flat road such as an urban area at the switching position when the vehicle height is reduced as shown in FIGS. A squaring hole 67 is provided on the opposite side of the oil passage 66 of the oil tank 66, and the squaring hole is connected to the oil tank 16 through an oil passage 68 that bypasses the push-side damping valve 70 and communicates with the oil reservoir B. Communicating. The square hole 67 is closed by the second check valve 37 of the rotary switching valve 34 at the switching position when the vehicle height is increased, as shown in FIG.

FIGS. 7 and 8 show the hydraulic circuit for adjusting the vehicle height when the rotary switching valve of the vehicle height adjusting unit is switched between the vehicle height increasing position and the vehicle height increasing position. 1 to 4 are denoted by the same reference numerals. The hydraulic jack portion and the rotary switching valve are only shown as belonging to the rear cushion.

[Action]

The operation of the self-pump type vehicle height adjusting device thus configured will be described. When traveling in an urban area, the rotary switching valve 34 is switched to the vehicle height down position shown in FIGS. 2, 4 and 8. During traveling, when the piston 4 enters the cylinder 3 during the compression stroke of the rear cushion 1, oil is supplied to the pump chamber A.
Then, the valve 4a is pushed up through the hole of the piston 4 to flow into the oil chamber A ', and the resistance at this time generates a compression-side damping force. At the same time, pump chamber A for the volume of piston rod
Flows through the first and second passages of the rotary switching valve 34 via the oil passages 39 and 40, while the second check valves 37 and 3
Since the oil passage to the jack is closed by 7 ',
After passing through the oil passages 38 and 38 'and passing through the square holes 67 and 67' (at this time, a compression-side damping force is generated), the oil passage 68 pushes the damping valve on the push side.
Bypasses 70 and flows into oil reservoir B of oil tank 16,
The gas chamber C performs volume compensation accompanying the intrusion and penetration of the piston rod. When the piston speed is high, the pipeline 15,
The oil flows into the oil reservoir B of the oil tank 16 from the oil passage 33 through the push-side damping valve 70 that has been pushed open through the pipe joint 17 and the oil passage 32. In the extension stroke, the oil in the oil chamber A 'passes through the oblique hole of the piston 4, pushes up the valve 4b and flows into the pump chamber A, and generates an extension-side damping force. This pump room A
Only the volume of oil from which the piston rod has been removed from the oil tank 16 flows from the oil reservoir B of the oil tank 16 to the oil passage 33, the push-side damping valve.
After passing through 70, the oil passage 32, the pipe joint 17, and the pipe 15, it flows into the pump chamber A of the rear cushion 1 and is refilled.

Set the rotary switch valve 34 to the first position when
When switching to the vehicle height-up switching position shown in FIGS. 3, 3 and 7, oil corresponding to the volume of the piston rod entering during the compression stroke of the rear cushion 1 flows from the pump chamber A through the line 15, the pipe joint 17, and the oil. Until the passage 32 reaches the opening pressure of the push-side damping valve 70, the oil in the pump chamber A passes through the oil passage 39 in one row and the oil passages 41 and 40 in the other row to reach the rotary switching valve 34. Through two rows of throughways 38, 38 ', through holes 51 of tappets 42, 42',
After passing through 51 ', the first check valves 43 and 43'
5, 45 'against the flow, then on the one hand via the pipe joint 46, the pipe 47 via the jack 10 of the rear cushion 1.
, While flowing into the hydraulic jack chamber E of the jack portion 25 of the front fork 20 from the pipe joint 46 'through the conduit 49 and the port 50. When the pressure of the hydraulic oil flowing from the inside of the pump chamber A of the rear cushion 1 reaches the opening pressure of the push-side damping valve 70, the oil pushes down the valve of the push-side damping valve 70, and the oil reservoir in the oil tank is lowered. Also flows into B. During the extension stroke of the rear cushion 1, the pressure in the pump chamber A is reduced, so the first check valve
43, 43 'are sucked and closed, the oil in the jack portion of the rear cushion 1 and the front fork 20 cannot flow backward, the check valve of the push-side damping valve 70 opens, and the oil in the oil reservoir B of the oil tank 16 opens. Is the same as before via the line 15 and the rear cushion 1
, And replenishes the oil in the volume of the piston rod that has flowed out. By repeating the compression and extension strokes of the rear cushion 1 as described above, the first check valves 43, 4
The self-pumping action is performed through the action of 3 ', and the oil is guided to the rear cushion 1 and the hydraulic jack chambers D and E of the jack portion of the front fork 20 for each compression stroke of the rear cushion 1, and the suspension springs 9 are provided. And gradually compress 24. When the internal pressures of the hydraulic jack chambers D and E of the jack portion exceed a predetermined value, the high-pressure oil moves the piston portion 62a of the relief valve 60 to the left side in FIG.
3 (shown in the upper half of FIG. 3), whereby the tip of the valve body 62 separates from the valve seat 62b, so that the oil in the pump chamber A of the rear cushion 1 flows from the oil passage 66 to the oil passage 65 Then, the oil is returned to the oil reservoir B of the oil tank 16.

In this manner, the suspension springs 9 and 24 are gradually compressed. However, since the vehicle body is balanced by the suspension springs 9 and 24, the respective plungers 13 and 28 compress the suspension springs 9 and 24 to suspend the vehicle. The spring load increases, and the vehicle body is pushed up to increase the vehicle height.

When the rotary switching valve 34 is switched to the vehicle height down position shown in FIGS. 2, 4, and 8 when the vehicle enters the city from the rough terrain, the hydraulic jack chamber of the jack portion of the rear cushion 1 and the front fork 20 is moved. The high-pressure oil in D and E passes through the first check valve 43, 43 'which is open, through the flat surface 52 of the tappet 42, the side hole 53, and the through passage 51, and the rotary switching valve 34, 34'. The second check valve 37,
37 'is pressed against the springs 36 and 36' to open, and mainly the oil passage 3
After passing through the square holes 67 and 67 ′ through the passages 8 and 38 ′, the oil flows into the oil reservoir B of the oil tank 16 from the oil passage 68, bypassing the push-side damping valve 70. As a result, the oil in the hydraulic jack chambers D and E in the jack portion of the rear cushion 1 and the front fork 20 is drained, and the plungers 13 and 28 are retracted, respectively, so that the vehicle height is reduced.

〔The invention's effect〕

In the present invention, a pump chamber formed inside the cylinder,
An oil tank cover is provided for a flow path connecting a hydraulic jack chamber provided in one mass member of a vehicle hydraulic shock absorber disposed between a vehicle body side and an axle side and an oil reservoir chamber formed in an oil tank. (Or the bottom of the oil tank), and a rotary switch valve is interposed in the flow path formed in this lid to connect the pump chamber to the hydraulic jack chamber when the vehicle height up position is connected, and to reduce the vehicle height Sometimes the hydraulic jack chamber and the pump chamber communicate with the oil sump chamber, and this oil sump chamber is formed in an oil tank provided separately from the vehicle hydraulic shock absorber, so that it can be arranged near the driver's seat of the motorcycle. It is convenient, and the switchability is improved. The rotor near the driver's seat The up or down as appropriate vehicle height can be achieved by switching the over switching valve.

Further, in the present invention, since the rear cushion performing the pumping action and the oil tank capable of temporarily storing the pressure oil in the hose are integrated into the vehicle height adjusting section including the rotary switching valve, both of these members are compact. It is gathered up. The oil tank may be a lid or a bottom of the oil tank. However, since an oil passage communicating the oil reservoir, the pump chamber, and the hydraulic jack chamber is formed in this portion, processing is facilitated, and assemblability is improved. .

As described in claim 1, two oil passages which are formed to intersect with each other while communicating with the rotary switching valve, the oil passage communicating with the pump chamber, and the hydraulic jack chamber on the outer periphery of the rotary switching valve communicate with each other. An oil passage communicating with the oil reservoir and a relief oil passage communicating with the oil reservoir through the relief valve; and a vehicle height adjusting unit provided with a relief valve, and a second check valve provided in the other oil passage of the rotary switching valve. The first check valve is provided in the oil passage communicating with the hydraulic jack chamber on the outer periphery of the rotary switching valve, so that the vehicle height can be adjusted to two positions, up and down, and the type of switching valve is changed to rotary. By using a switching valve, many oil passages can be arranged on the outer periphery, and the space for the vehicle height adjustment unit can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall view of a first vehicle hydraulic shock absorber and a second vehicle hydraulic shock absorber provided with a self-pump type vehicle height adjusting device according to the present invention. FIG. 4 is a vertical cross-sectional view showing a state where the switch is switched to the up position, and FIG.
FIG. 3 is a partial longitudinal sectional view showing a state in which a rotary switching valve of a vehicle height adjusting unit in FIG. 1 is switched to a vehicle height down position;
The figure is a partial sectional view taken along line III-III in FIG.
4 is a partial sectional view taken along line IV-IV of FIG. 2, FIG. 5 is an enlarged sectional view of the push-side damping valve shown in FIG. 1, and FIG. FIGS. 7 and 8 are perspective views of the tappet between the check valves of FIGS. 7 and 8, respectively. FIGS. It is. 1 ... Rear cushion as vehicle hydraulic shock absorber, 3
... cylinder, 4 ... piston, A ... pump chamber, 6 ...
... Piston rod, 7,8 ... Spring receiver, 9,24 ... Suspension spring, 10,25 ... Jack part, D, E ... Hydraulic jack chamber, 16
…… Oil tank, 20… Front fork as hydraulic shock absorber for vehicle, 30… Vehicle height adjustment unit, 34… Rotary switching valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B60G 17/00-17/08 B62K 25/00-25/32 F16F 9/50

Claims (4)

(57) [Claims] A pump chamber is formed by allowing a piston rod having a piston at a tip to enter and leave an oil chamber in a cylinder of a vehicle hydraulic shock absorber. The pump chamber is formed between an oil sump chamber and a vehicle body side and an axle side. The hydraulic oil sucked from the oil reservoir is sent to the hydraulic jack chamber when the vehicle height is increased, and the hydraulic oil in the hydraulic jack chamber is returned to the oil reservoir when the vehicle height is lowered. In a vehicle hydraulic shock absorber for adjusting a vehicle height, a rotary switching valve is provided inside, and an oil passage communicating with a pump chamber (a) and an oil passage communicating with a hydraulic jack chamber (b) are provided around the rotary switching valve. A vehicle height adjusting unit having an oil passage (C) communicating with the oil reservoir and a relief oil passage (D) communicating with the oil reservoir through the relief valve; Communicate with each other The one oil passage (a) connects the oil passage communicating with the pump chamber and the oil passage communicating with the hydraulic jack chamber when the vehicle height up position is set, and the oil passage (a) when the vehicle height down position is set. The oil passage communicating with the reservoir is connected to the relief oil passage, and the other oil passage (b) is connected to the oil passage communicating with the oil reservoir and the relief oil passage when the vehicle height increasing position is set. At the time of setting the down position, the oil passage communicating with the pump chamber and the oil passage communicating with the hydraulic jack chamber are connected. From the intersection of the other oil passage (b) of the rotary switching valve and one oil passage (a), A second check valve is provided on the side opposite to the oil passage communicating with the oil reservoir when the vehicle height increasing position is set, in a direction for preventing flow from the pump chamber to the oil reservoir, and an oil passage communicating with the hydraulic jack chamber. First in the direction to block the flow from the hydraulic jack chamber to the pump chamber. A check valve is provided, the first check valve is a rotary switching valve self-pumped vehicle height adjusting device for a hydraulic shock absorber for a vehicle, characterized in that the opening in the vehicle height down when setting a position of. 2. The vehicle according to claim 1, wherein an oil tank having an oil reservoir formed therein is formed separately from a main body of the vehicle hydraulic shock absorber, and said oil tank is provided with said vehicle height adjusting portion. 2. The self-pump type vehicle height adjusting device for a vehicle hydraulic shock absorber according to 1. 3. A tappet is slidably inserted into an oil passage communicating with a hydraulic jack chamber between a rotary switching valve and a first check valve, and a cutout surface is formed on a part of an outer periphery of the rotary switching valve. 3. The hydraulic pressure for a vehicle according to claim 1, wherein the first check valve is opened when the tappet is located at a circumferential portion of the rotary switching valve, and is closed when the tappet is located at the notch surface. Self-pump type vehicle height adjustment device for shock absorber. 4. A pump chamber is formed by allowing a piston rod having a piston at its tip to enter and exit an oil chamber in a cylinder of a hydraulic shock absorber for a vehicle, and the pump chamber is formed between an oil sump chamber and a vehicle body side and an axle side. Hydraulic oil sucked from the oil reservoir is sent to the hydraulic jack chamber when the vehicle height is increased, and the hydraulic oil in the hydraulic jack chamber is returned to the oil reservoir when the vehicle height is lowered. In a vehicle hydraulic shock absorber for adjusting the height, a rotary switching valve, an oil passage communicating between the pump chamber and the hydraulic jack chamber, an oil passage branching from the oil passage and communicating with the oil reservoir and a relief valve are provided. An oil passage communicating with the oil reservoir is formed through the oil passage, a rotary switching valve is interposed at a branch point of these oil passages, and the relief valve is provided in an oil passage connecting the rotary switching valve and the hydraulic jack chamber. Height adjustment section The hydraulic oil is sent from the pump chamber to the hydraulic jack chamber through the rotary switching valve to set the vehicle height up position via the rotary switching valve, preventing the flow from the pump chamber to the oil sump chamber and setting the vehicle height down position. Occasionally, hydraulic oil is sent from the pump chamber to the oil sump chamber, preventing the flow from the pump chamber to the hydraulic jack chamber, and when the vehicle height has been increased, hydraulic oil is sent from the pump chamber to the oil sump chamber via the relief valve. A self-pump type vehicle height adjusting device for a vehicle hydraulic shock absorber, wherein hydraulic oil in a hydraulic jack chamber is returned to an oil reservoir when a vehicle height down position is set.