JP3108078B2 - Height adjustment device for vehicle hydraulic shock absorber - Google Patents

Description

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

[Prior art and problems to be solved]

Normally, a hydraulic shock absorber of a two-wheeled vehicle is provided between a vehicle body and an axle of front and rear wheels, respectively, and includes a vehicle height adjusting device that adjusts a distance between the vehicle body and the axle to adjust a vehicle height. In this vehicle height adjusting device, as shown in FIG. 8 or FIG.
The hydraulic shock absorber of the rear wheel of the two-wheeled vehicle that performs a self-pumping operation during traveling, that is, the pump chamber A in the cylinder of the rear cushion 1 is switched through the first oil passage 31 between the vehicle height down position and the vehicle height up position. The oil passage 31 is branched into two at the downstream of the switching valve mechanism, and the jack chamber B of the hydraulic jack section 10 provided on the outer periphery of the upper portion of the rear cushion and the shock absorber for the front wheels, i.e. It is connected to a jack chamber C of a hydraulic jack section 25 provided at an upper part in the inner cylinder of the fork. The switching valve mechanism 50 is provided with a rotary switching valve 51, and a tappet 55 and a third check valve 56 are provided downstream of and adjacent to the switching valve 51. The check valve is provided with two hydraulic jack chambers B. , C to prevent the hydraulic oil from flowing into the pump chamber A. A first check valve 39 is provided in the second oil passage 36 branched from the first oil passage 31 upstream of the switching valve mechanism 50 so that the pressure oil does not flow toward the oil reservoir D. .

During traveling of the motorcycle, at the time of setting the switch height of the switching valve 51, the hydraulic oil discharged from the pump chamber A flows into the jack chambers B and C attached to the hydraulic shock absorber, and pushes down the suspension spring, The piston rod fixed to one end of the suspension spring is pulled out of the cylinder, and the vehicle body is pushed upward to increase the vehicle height. When the switching valve 51 is set to the vehicle height down position, the hydraulic oil returns from the jack chambers B and C to the oil reservoir D, and reduces the vehicle height. When the occupant stops the vehicle and gets off the vehicle, the weight on the vehicle body side is reduced accordingly. In particular, like a motorcycle, the body is light,
In the case of a vehicle in which the occupant occupies a large portion, the reduction ratio is large. Further, when the side stand is set up, a considerable portion of the weight on the vehicle body side is shared by the side stand, so that the weight is further reduced. However, for the purpose of preventing cavitation, hysteresis, etc. of the hydraulic shock absorber, the hydraulic oil is supplied to the gas chamber E adjacent to the oil reservoir D communicating with the pump chamber A in the cylinder of the hydraulic shock absorber via a movable partition member. The pressurized gas is sealed to pressurize the hydraulic oil. The pressurized gas sealed in the gas chamber E is supplied to the pump chamber A, the jack chambers B and C in the cylinder of the hydraulic shock absorber.
In addition, the hydraulic oil in the pipeline connecting these fluids is constantly pressurized constantly.

As described above, when the weight on the vehicle body side is reduced, that is, the load received by the plunger of the jack chamber B of the rear cushion, which receives the weight on the vehicle body side via the suspension spring, and in particular, has a large shared load, is reduced. At this time, the switching valve 51 at the vehicle height down position closes the oil passage to the jack chamber B by the second check valve 53 (FIG. 9).
There is a sliding gap between the switching chamber 51 and the hole of the main body 52 in which the switching valve is fitted.
The oil passage of the hydraulic oil having the sealing pressure on the upstream side of the oil reservoir communicates with the oil passage through the sliding gap, so that the sealing pressure of the hydraulic oil is smaller than the load applied to the jack piston reduced as described above. The hydraulic oil gradually flows into the jack chamber B and displaces the jack piston, so that the vehicle height increases. If the vehicle height increases when the motorcycle is stopped in this way, not only will it become difficult for the occupant to ride next time, but also when riding in an urban area, the oil in the jack room B will be reduced by the weight of the occupant and the weight of the vehicle body. It is necessary to return to the oil sump D and wait until the vehicle height decreases to the normal height.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle height adjusting device for a vehicle hydraulic shock absorber having a vehicle height increase prevention device when the vehicle is stopped in order to eliminate the above-mentioned drawbacks.

[Means for solving the problem]

According to the first aspect of the present invention, the piston provided at the tip of the piston rod is reciprocally accommodated in the cylinder of the hydraulic shock absorber disposed between the vehicle body side and the axle side, and the piston in the cylinder is reciprocated. The oil chamber expanded and contracted by the reciprocating motion is used as a pump chamber, an oil reservoir adjacent to the pressurized gas chamber is formed in the oil tank via a movable partition member, and the oil reservoir and the pump chamber are formed as a second chamber. The first check valve is provided in the second oil passage in a direction for preventing a flow of hydraulic oil from the pump chamber to the oil reservoir, and is provided between the vehicle body side and the axle side. A hydraulic jack is provided, a hydraulic jack chamber in the hydraulic jack communicates with the pump chamber via a first oil passage, a switching valve mechanism is interposed in the first oil passage, and A third oil passage branched through the switching valve mechanism and communicating with the oil reservoir; The switching valve mechanism includes a main body and a switching valve inserted through a sliding gap in a hole of the main body, and the switching valve is connected to the oil reservoir chamber from the pump chamber when the vehicle height is increased. And is set so as to allow the flow from the pump chamber to the hydraulic jack chamber, and the operating oil in the oil reservoir chamber is transferred from the pump chamber through the first oil passage from the pump chamber. It is set to be supplied to the hydraulic jack chamber, and to prevent the flow from the pump chamber to the hydraulic jack chamber and to allow the flow from the hydraulic jack chamber to the oil sump chamber when the vehicle height is down. A vehicle oil pressure adjusting device for returning the hydraulic oil in the hydraulic jack chamber to the oil reservoir via the third oil passage, the first oil downstream of the switching valve mechanism; The road branches into two and communicates with the hydraulic jack chamber A fourth check valve is provided in one of the branched oil passages in a direction to prevent the flow of the hydraulic oil to the hydraulic jack chamber, and the other of the branched oil passages is blown in a direction to allow the flow to the hydraulic jack chamber. A valve is provided, and the opening pressure of the blow valve is set to be equal to or higher than the gas filling pressure of the gas chamber.

According to a second aspect of the present invention, in the first aspect, the switching valve mechanism further includes a main body and a switching valve inserted through a sliding gap in a hole of the main body. Is 2
Two oil paths are provided at right angles, a second check valve is provided at one port of one oil path, and the rotatable switching valve is configured such that when the vehicle height is increased, the second check valve is connected to the second check valve. A switch is set to block the flow from the pump chamber to the oil sump chamber facing the third oil passage, and to allow the flow from the pump chamber to the hydraulic jack chamber. Hydraulic oil can be supplied from the pump chamber to the hydraulic jack chamber via the first oil passage, and when the vehicle height is down, the second check valve faces the downstream side of the first oil passage. The hydraulic pump chamber is set so as to block the flow from the pump chamber to the hydraulic jack chamber, and to allow the flow from the hydraulic jack chamber to the oil reservoir chamber. Return to the oil reservoir via the oil passage It is obtained so as to enable.

〔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 which can simultaneously adjust the vehicle height of a motorcycle rear cushion and a front fork which are vehicle hydraulic shock absorbers.

A rear cushion 1, which is a hydraulic shock absorber on the rear wheel side, includes a cylinder 3 having a vehicle body mounting member 2 at one end, a piston 4 slidably mounted in the cylinder 3, and a mounting member 2 from the piston. A piston rod 6 protruding to the opposite side and having an axle mounting member 5 at its free end, and a spring receiver 7 provided at the piston rod side end;
A suspension spring 9 is stretched between the suspension spring 9 and a spring receiver 8 provided at the end on the cylinder side. The piston 4 is provided with a damping force generator as usual.

The rear wheel-side jack portion 10 forming a part of the 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 this sleeve. A plunger 13 is slidably mounted between the inner peripheral surface of the plunger case and the outer peripheral surface of the sleeve, and a collar 8a is slidably mounted between the end of the plunger 13 and the spring receiver 8 simultaneously with the plunger 13. ing. In this manner, the rear-wheel-side hydraulic jack chamber B is formed between the upper end surfaces of the plunger case 12 and the plunger 13.

A front fork 20, which is a hydraulic shock absorber on the front wheel side, includes an axle-side outer cylinder 21 and a body-side inner cylinder 22 slidable in the outer cylinder 21.
A spring receiver (not shown) at the upper end of a seat pipe (not shown) projecting upward from the bottom of the outer cylinder;
A suspension spring 24 is stretched between the spring support 23 and the upper end of the suspension.

Further, a jack portion 25 of the front fork 20 which constitutes a part of the self-pump type vehicle height adjusting device has a plunger case 26 attached to a fork bolt 22a fixed to an 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.
As a result, a front-wheel-side hydraulic jack chamber C is formed between the plunger case 26 and the plunger 28. The spring receiver 23 is attached to the tip of the rod 29.

A first oil passage 31 is provided for connecting the pump chamber A in the cylinder of the rear cushion 1 to the hydraulic jack chamber B of the jack section 10 of the rear cushion 1 and the hydraulic jack chamber C of the jack section 25 of the front fork 20. First oilway
A vehicle height adjustment unit 30 is provided at 31, which is actually disposed at the rear lower part of the seat of the motorcycle and can be operated in the riding posture.

As shown in FIG. 2, an oil tank 34 in which a free piston 33 is inserted is screwed to a main body 32 of the vehicle height adjusting section 30, and the main body 32 also serves as a cover member of the oil tank. One chamber E partitioned by a free piston 33 as a movable partition member is filled with gas, and the other chamber D forms an oil reservoir.

In FIG. 1, an oil passage 31b of a pipe joint 35 of a main body 32 connected to a pump chamber A in a cylinder of the rear cushion 1 via an oil passage 31a is connected to an oil passage 31c.
A valve mechanism 40 that generates a compression-side damping force is provided. Since this valve mechanism is not directly related to the gist of the present invention, a detailed description is omitted. On the other hand, the first oil passages 31b and 3
A second oil passage 36 (FIGS. 2 and 3), which intersects at right angles with 1c and communicates with the lower oil reservoir D, is seated on a seat 37 by a spring 38, and is always connected to the oil reservoir D. A first check valve 39 urged to close the opening is provided.

Furthermore, the first oil passage 31 that goes downstream from the valve mechanism 40
The d is guided to the switching valve mechanism 50 via an oil passage 31e reaching the hydraulic jack chamber B of the rear cushion 1. This switching valve mechanism 5
0 has a rotatable switching valve 51, and in this switching valve 51,
Two orthogonal oil passages 31h, 31i (see FIG. 2 or FIG. 3) are provided. The position of the switching valve 51 in FIGS. 1 and 2 is the vehicle height up position, and FIG. 3 is the vehicle height down position. The switching valve 51 is rotated by 90 ° and returned by 90 °, so that a sliding gap is formed in a hole in the main body 32 so as to take two positions, a vehicle height increasing position and a vehicle height decreasing position. It is charged with. When the vehicle height is increased (FIGS. 1 and 2), one of the ports at both ends of the orthogonal oil passage 31h drilled in the switching valve 51 is connected to the upstream side of the first oil passage 31. It is set so as to face 31 e and the other port faces downstream 31 k of the first oil passage 31. As can be seen from FIG. 2, the opening surface of the port is located on the bottom surface of the circumferential groove recessed inward from the outer circumferential surface of the switching valve 51. This groove is provided over an angle of 180 ° or more. At the vehicle height down position (FIG. 3), one port of the oil passage 31h faces the third oil passage 54 communicating with the oil reservoir D, and the other port faces the relief oil passage 66. Set. In the other orthogonal oil passage 31i in the switching valve 51, an orifice 31j is formed in one port, and this orifice is fixed to the chrysant washer 52a whose outer periphery is caulked and fixed to the other port opening surface of the oil passage 31i. It is always closed by a spring 52a biased between the second check valve 53. Oil passage 31i
When set to the vehicle height up position (Figs. 1 and 2),
The orifice 31j faces the third oil passage 54 communicating with the oil reservoir D, and the port on the opposite side of the orifice is a relief oil passage.
Facing 66. When set to the vehicle height down position (FIG. 3), the orifice 31j faces the downstream side 31k of the first oil passage 31, and the port on the opposite side of the orifice is the upstream side 31e.
Turn to. A valve seat 59 (FIG. 2a) is formed on the downstream side of the small-diameter cylindrical hole 75 in the downstream 31k of the first oil passage 31. A third check valve 56 is pressed by a spring 57 on this valve seat. ing. One end of the small-diameter cylindrical hole 75 is
A cylindrical tappet that slides into a circumferential groove 51a formed over 0 ° and opens and closes the third check valve 56 at the other end.
55 (FIG. 4) are slidably mounted. Tappet 55
Is the oil passage 31l passing through the center, as is clear from FIG.
And a cutout surface 55a of the tappet 55 orthogonal to the oil passage 31l.
And a branch path 31m that opens to the outside. Further, as shown in FIG. 1, the first oil passage 31k is connected to a laterally branched oil passage 31n from a pipe joint 58 through an oil path 31g and a pipe joint 58a, and further to a stop according to the present invention described later. Of the rear cushion 1 on the rear wheel side via the vehicle height increase prevention device 80, and the front wheel side front via an oil passage 31g 'via a pipe joint 58' provided in the oil passage 31n. The fork 20 is connected to the hydraulic jack chamber C.

The oil passage 31k is connected to the first blow valve 70 via a horizontal oil passage 68, as shown in FIGS.
This first blow valve is connected to the oil reservoir D via oil passages 69 and 54.
It is connected to the. The blow valve 70 has a ball 73 which is held by the guide holder by the spring 71 and the valve seat is always closed.However, when the hydraulic oil downstream of the third check valve 56 abnormally rises in pressure when the vehicle height increases, the blow valve 70 It is provided as a safety circuit that opens against this and returns this pressure to the oil reservoir D.

Further, when the internal pressure of the hydraulic jack chambers B and C of the jack sections 10 and 25 becomes higher than a predetermined value when the vehicle height is increased, the oil in the pump chamber A in the cylinder of the rear cushion 1 is supplied to the oil reservoir chamber of the oil tank 34. To return to D, a relief valve 60 (FIG. 2 or FIG. 3) connects the hydraulic jack chambers B and C of the jack sections 10 and 25 to the pump chamber A in the cylinder of the rear cushion 1 respectively. The relief oil passages 66 and 65 branch from the oil passage 31 are provided. The relief valve 60 is moved against the spring by the high-pressure oil in the jack chamber acting via the oil passage 64, whereby the relief oil passages 66 and 65 communicating with the oil reservoir D are opened, The hydraulic oil from the pump chamber A is returned to the oil reservoir D.

1 and 5, a description will be given of a vehicle height increase prevention device 80 at the time of a stop according to the present invention.

A conduit 31g for guiding the vehicle from the vehicle height adjusting unit 30 to the hydraulic jack chamber B on the rear cushion side is connected to the jack unit via a fitting 58a.
It is connected to a plunger case 12 for 10 and then diverges into two oil passages 81 and 82 leading to jack chamber B.
A fourth check valve 83 is provided in one oil passage 81, and a second blow valve 84 is provided in the other oil passage 82.

The fourth check valve 83 has a valve seat 86 having a through hole 85, and a guide holder 87 fitted to a protruding portion of the valve seat.
A hole for accommodating 88 and a spring 89 for urging the ball to be seated in the opening of the valve seat 86 is provided. The hole is provided in the upstream oil passage 31g and the downstream oil passage 82. Through a plurality of radial transverse holes 90 and an annular gap 91 around the small diameter portion. At the time of assembling, these parts can be assembled easily by screwing the guide holder 87 into the hole forming the oil passage 81 by integrally assembling these parts.

A second blow valve 84 provided in an oil passage 82 branched from the fourth check valve 83 is provided with a cylindrical guide holder 93 having a through hole at the bottom, and a slide fit slidably in the guide holder 93. A holder 94, a ball 95 held by the slide holder 94, a valve seat 96 having a valve seat for the ball 95, and a hole in the slide holder 94 for urging the ball 95 toward the valve seat 96. It has a spring 97 inserted between the inner end of 94a and the end face of the guide holder 93. In the hole 94a of the slide holder 94, a plurality of oblique through holes 98 are provided in a head 94b holding a ball 95, and through these through holes, a hole 94a in the slide holder 94 is formed around the head 94b. It communicates with the annular gap. The valve seat 96 has a hole 99 in which the ball 95 is seated, and the hole 99 communicates with the oil passage 82 through a plurality of radial transverse holes 100 and an annular gap 101 around the small diameter portion. The second blow valve 84 can be assembled easily in the same manner as the fourth check valve 83, and can be easily assembled by turning and screwing the valve seat 96 into the hole forming the oil passage.

FIGS. 6 and 7 show the arrangement of the vehicle height adjusting device of the hydraulic shock absorber described above in a schematic hydraulic circuit as compared with FIGS. 7 and 8 showing the prior art.

The operation during traveling of the vehicle height adjusting device of the hydraulic shock absorber configured as described above will be briefly described mainly with reference to FIGS. 6 and 7. When traveling in an urban area, the switching valve 51 is moved to the vehicle height down position (the seventh position). (Fig.). While running, rear cushion 1
Hydraulic oil flows from the pump chamber A through the first oil passage 31 into the vehicle height adjustment unit 30 by the compression stroke of the piston 4, where the first check valve 39 of the second oil passage 36 is Since it is closed, it flows into the switching valve mechanism 50 via the valve mechanism 40 that generates a compression-side damping force. In the vehicle height down position, the oil passage to the jack portion is closed by the second check valve 53 in the switching valve 51, so that the oil sump D through the third oil passage 54
Flows into. In the extension stroke, the pressure in the pump chamber A is reduced, so that the first check valve 39 is sucked and opened, and the hydraulic oil from the oil reservoir D passes through the opened first check valve 39 to the pump chamber A. Incoming to compensate for the volume of oil removed from the piston rod.

When the switching valve 51 is switched to the vehicle height-up position (FIG. 6) when traveling on a rough terrain, the hydraulic oil flows from the pump chamber A to the oil passage 31 by the compression stroke of the piston of the rear cushion 1.
, And flows into the vehicle height adjustment unit 30, and then flows into the switching valve mechanism 50 via the valve mechanism 40 that generates a compression-side damping force. The hydraulic oil passes through the oil passage in the switching valve 51, further passes through the center oil passage 31l (FIG. 4) of the tappet 55, pushes up the third check valve 56 against the spring, and passes through the oil passage 31g. The oil flows into the jack portion 25 of the front fork 20 and also flows into the oil passage 81 provided in the jack portion 10 of the rear cushion 1. In the oil passage 81, since the fourth check valve 83 is closed, the oil branched further. It flows to the path 82 and presses the second blow valve 84. The valve opening pressure of the blow valve is set to be equal to or higher than the pressure of the hydraulic oil supplied by the gas pressure of the oil tank, but the high-pressure hydraulic oil generated by the compression stroke of the piston of the rear cushion 1 is subjected to the force of the spring 97. Since the second blow valve 84 can be overcome, the second blow valve 84 is easily opened and flows into the jack chamber B of the rear cushion. During the extension stroke of the rear cushion 1, the third check valve 56 is sucked and the oil in the jack portion cannot flow backward. However, since the first check valve 39 is opened, the oil in the oil reservoir D flows into the pump chamber A and the piston Compensate for the volume of oil lost by the rod.

The self-pumping action is performed by repeating the compression and extension strokes of the rear cushion 1, and the suspension springs are gradually compressed by the jack chambers B and C. However, the vehicle body is balanced by the suspension springs 9 and 24. As a result, the suspension spring load increases, the body is pushed up, and the vehicle height increases.

The switch valve 51
Is switched to the vehicle height down position, the oil in the jack chambers B and C is released by the switching valve 51 due to the weight of the occupant and the vehicle body.
Third check valve pushed up and opened via 55
After passing through the cutout surface and the through hole of the tappet 55, the second check valve 53 in the switching valve is pushed open, and the third oil passage 54
Through the oil reservoir D. As a result, the vehicle height decreases.

As described above, when the occupant gets off the motorcycle and stands on the side stand after stopping the vehicle, the suspension spring is applied to the plunger of the jack chamber B on the rear wheel side, which has a large shared load, by the occupant weight and the vehicle weight applied to the side stand, particularly. And the pressure of the sealed oil in the vehicle height adjustment hydraulic circuit, which is constantly pressurized by the pressure of the gas chamber E of the oil tank, exceeds the reduced load received by the plunger of the jack chamber B. Become something. As a result, the filled oil in the vehicle height adjusting hydraulic circuit flows toward the jack chambers B and C via the sliding gap between the switching valve 51 and the fitting hole,
In the case where the vehicle height increase prevention device of the present invention is not provided, the vehicle height is increased by flowing into the jack chamber B of the rear cushion 1, which has a large shared load and a large weight reduction ratio, and pushes up the plunger. However, according to the vehicle height increasing device at the time of stop of the present invention, at the vehicle height decreasing position at the time of stop, the sealed oil flowing from the sliding gap around the switching valve 51 to the jack chamber side is the fourth check valve of the oil passage 81. 83 is closed, so it flows to the further branched oil passage 82 and the second blow valve 84
However, since the valve opening pressure of this valve is set to be equal to or higher than the working oil filling pressure by the spring 97, the second blow valve 84 does not open and cannot flow into the jack chamber B.

〔The invention's effect〕

In the vehicle height adjusting device of the vehicle hydraulic shock absorber according to the present invention, a third oil passage branching from the first oil passage communicating the pump chamber and the jack chamber and communicating with the oil reservoir is formed, and further the pump chamber is formed. And a first oil passage communicating with the jack chamber is branched into two from the downstream side of the oil reservoir, a blow valve is interposed in one of the branched oil passages, and a pump chamber is provided in the other branched oil passage. A fourth check valve is interposed in the direction to block the flow of hydraulic oil from
Since there is a vehicle height increase prevention device when the vehicle is stopped, the opening pressure of the blow valve is set to be equal to or higher than the sealing pressure of the hydraulic oil, the switching valve is set to the vehicle height down position as described above. When the occupant gets off the vehicle, the load on the plunger in the jack chamber is reduced, so that hydraulic oil with a constant filling pressure tries to flow from the oil sump chamber side upstream to the jack chamber, but the hydraulic oil downstream of the oil sump chamber The blow valve, which is set at a pressure equal to or higher than the pressure at which the hydraulic oil is charged, prevents the flow into the jack chamber. Therefore, the vehicle height remains unchanged while being set at the vehicle height down position. Moreover, when supplying hydraulic oil to the jack chamber from the pump chamber of the hydraulic shock absorber,
Since the hydraulic oil has a pressure considerably higher than the pressure of the hydraulic oil due to the pumping action, there is no problem in that the hydraulic oil from the pump chamber opens the blow valve and flows into the jack chamber. Further, the fourth check valve provided in parallel with the blow valve serves to return the high-pressure oil in the jack chamber to the oil reservoir without resistance when the vehicle is switched from the vehicle height increasing position to the vehicle height decreasing position.

[Brief description of the drawings]

FIG. 1 is an overall view of a rear cushion and a front fork of a motorcycle provided with a vehicle height adjusting device having a vehicle height increasing preventing device according to the present invention, in which a switching valve of the vehicle height adjusting device is in a vehicle height increasing position. FIG. 2 is a partial cross-sectional view of the vehicle height adjustment section taken along line II-II in FIG. 1, FIG. 2a is a switching valve, a tappet, and FIG. FIG. 3 is an enlarged view of the vicinity of a third check valve, and FIG. 3 is a cross-sectional view of a vehicle height adjusting unit similar to FIG. 2, but showing a state in which a switching valve is switched to a vehicle height down position; FIG. 5 is a perspective view of a tappet used in the switching valve mechanism, FIG. 5 is a cross-sectional view of the vehicle height increase prevention device at the time of stoppage according to the present invention cut along the line VV in FIG. 1, and FIG. Is a rear cooker equipped with a vehicle height adjustment device having a vehicle height increase prevention device during a stop according to the present invention. FIG. 7 is a schematic hydraulic circuit diagram for a vehicle and a front fork, showing a state in which the vehicle is switched to a vehicle height up position, and FIG. 7 is a schematic hydraulic circuit diagram similar to FIG. FIG. 8 is a schematic hydraulic circuit for a hydraulic shock absorber provided with a conventional vehicle height adjusting device, showing a state in which the vehicle is switched to a vehicle height up position, and FIG. 9 is a diagram showing a state in which the vehicle is switched to a vehicle height down position. FIG. 9 is a schematic hydraulic circuit diagram similar to FIG. 1 ... hydraulic shock absorber, 3 ... cylinder, 4 ... piston,
6 ... Piston rod, 10 ... Hydraulic jack, 31 ...
First oil passage, 33 ... free piston (movable partition member),
34 ... oil tank, 36 ... second oil passage, 39 ... first check valve, 50 ... switching valve mechanism, 51 ... switching valve, 53
…… second check valve, 54 …… third oil passage, 56 ……
Third check valve, 81 ... One oil passage, 82 ... The other oil passage, 83 ... Fourth check valve, 84 ... Blow valve

Claims (2)

(57) [Claims] A piston provided at a tip end of a piston rod is reciprocally accommodated in a cylinder of a hydraulic shock absorber disposed between a vehicle body side and an axle side, and the piston in the cylinder reciprocates. An oil chamber expanded and contracted by the pump chamber, an oil reservoir adjacent to the pressurized gas chamber via a movable partition member in the oil tank, and the oil reservoir and the pump chamber are connected via a second oil passage. A first check valve is provided in the second oil passage in a direction to prevent the flow of hydraulic oil from the pump chamber to the oil reservoir, and a hydraulic jack is provided between the vehicle body side and the axle side. A hydraulic jack chamber in the hydraulic jack communicates with the pump chamber via a first oil passage, a switching valve mechanism is interposed in the first oil passage, and the switching valve mechanism is provided from the first oil passage. Branch through
A third oil passage communicating with the oil reservoir is provided, and the switching valve mechanism includes a main body and a switching valve inserted through a sliding gap in a hole of the main body, and the switching valve has a vehicle height. At the time of the up state, switching is set so as to block the flow from the pump chamber to the oil sump chamber and to allow the flow from the pump chamber to the hydraulic jack chamber, and the hydraulic oil in the oil sump chamber is A pump is supplied from the pump chamber to the hydraulic jack chamber via a first oil passage to prevent a flow from the pump chamber to the hydraulic jack chamber when the vehicle height is reduced, and the oil is supplied from the hydraulic jack chamber to the hydraulic jack chamber. A vehicle height adjustment device for a vehicle hydraulic shock absorber that is set to be switched so as to allow a flow to the reservoir and returns the hydraulic oil in the hydraulic jack chamber to the oil reservoir through the third oil passage. The first oil passage downstream of the switching valve mechanism is divided into two. A fourth check valve is provided in one of the branched oil passages in a direction for preventing the flow of hydraulic oil to the hydraulic jack chamber, and the other hydraulic passage is provided in the other hydraulic passage. A vehicle height adjusting device for a vehicle hydraulic shock absorber, wherein a blow valve is provided in a direction allowing flow to a chamber, and a valve opening pressure of the blow valve is set to be equal to or higher than a gas charging pressure of the gas chamber. 2. The switching valve mechanism comprises a main body and a switching valve inserted into a hole of the main body through a sliding gap. A second check valve is provided at one port of the passage, and the rotatable switching valve is configured such that, when the vehicle height is increased, the second check valve faces the third oil passage from the pump chamber. It is switched and set to block the flow to the oil reservoir and allow the flow from the pump chamber to the hydraulic jack chamber,
Hydraulic oil in the oil reservoir can be supplied from the pump chamber to the hydraulic jack chamber via the first oil passage, and when the vehicle height is down, the second check valve is connected to the first oil passage. The switch is set to block the flow from the pump chamber to the hydraulic jack chamber facing the downstream side and to allow the flow from the hydraulic jack chamber to the oil sump chamber, and to operate the hydraulic jack chamber. The vehicle height adjusting device for a vehicle hydraulic shock absorber according to claim 1, wherein the oil can be returned to the oil reservoir via the third oil passage.