JP3170484B2 - Self-pump type vehicle height adjustment device for vehicle hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston rod which advances and retreats an oil chamber in a cylinder to and from a hydraulic shock absorber, a pump chamber formed in the oil chamber in the cylinder, and an oil reservoir communicating with the oil chamber in the cylinder. A self-pumping vehicle height adjustment device that has a hydraulic jack for adjusting the distance by adjusting the distance between the vehicle body and the axle, supplying and discharging hydraulic oil between the pump chamber and the jack chamber, and adjusting the vehicle height About.

[0002]

2. Description of the Related Art A self-pump type vehicle height adjusting device for a vehicle hydraulic shock absorber is known, for example, from Japanese Patent Application Laid-Open No. 58-56985. In this case, the vehicle hydraulic shock absorber to which the self-pump type vehicle height adjustment device is attached includes a cylinder having an attachment member at one end, a piston slidably fitted in the cylinder, and a free end projecting from the piston and having a free end. A piston cushion having an attachment member, 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. 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 the outer periphery of the plunger case. A high-pressure oil chamber is formed between the spring seat at the inner end of the plunger and the plunger case. Further, a check valve which is opened at the time of compression and closed at the time of extension is provided at the end of the piston rod in the cylinder, and the check valve and the high-pressure oil chamber of the hydraulic jack portion communicate with each other through a long hole provided concentrically with the piston rod. While the motorcycle is running, the check valve at the tip of the piston rod opens during the compression stroke of the rear cushion, and the check valve closes during the extension stroke.The oil in the oil chamber of the cylinder passes through the long hole in the piston rod and the hydraulic jack Flow into high pressure oil chamber. By this repetition, the oil is guided to the high-pressure oil chamber by the pump action in each compression stroke, and the high-pressure oil chamber expands, and the plunger compresses the suspension spring. Since the body is balanced by the suspension spring, the spring load increases due to the compression of the suspension spring,
Push up the body to increase the vehicle height.

[0003]

However, in this self-pump type vehicle height adjusting device, the vehicle height is increased when traveling on rough terrain.
But can move from wasteland to city
When lowering the vehicle height by
Impairs stability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-pump type vehicle hydraulic shock absorber having a vehicle height adjustment switching device capable of appropriately changing the vehicle height according to the traveling road surface and having a reduced size. Is the vehicle height in the adjustment device raised?
To avoid a sudden drop in vehicle height
And to improve maneuverability.

[0005]

According to the first aspect of the present invention, there is provided a piston rod for moving forward and backward in a cylinder of a hydraulic shock absorber, a pump chamber formed in the cylinder, an oil reservoir communicating with the pump chamber, and a vehicle body. And a jack portion for adjusting the vehicle height by adjusting the distance between the axles, and the hydraulic oil in the oil reservoir can be supplied to the hydraulic jack chamber of the jack portion via the pump chamber to increase the vehicle height. In a self-pump type vehicle height adjustment device that adjusts the vehicle height by returning the hydraulic oil in the hydraulic jack chamber to the oil reservoir and enabling the vehicle height to decrease, the pump chamber in the cylinder and the A vehicle height adjustment switching device is interposed in the first oil passage communicating with the hydraulic jack chamber,
A rotatable switching valve is housed in a hole provided in the body of the vehicle height adjustment switching device, a pump chamber side oil path of the first oil path, and a jack chamber side oil path of the first oil path, A third oil passage communicating with the oil reservoir and a relief oil passage for returning oil in a pump chamber to the oil reservoir through a relief valve are opened in the switching valve housing surface of the hole, and the switching valve Has two oil passages, one oil passage and the other oil passage, the two oil passages are connected to each other,
In addition, when the vehicle height is increased, one port of one oil path of the switching valve is provided in a pump chamber side oil path of the first oil path, and the other port is provided in a jack chamber side oil. One port of the other oil path is connected to the third oil path, and the other port is connected to the relief oil path. A port is connected to the third oil passage, the other port is connected to the relief oil passage, one port of the other oil passage is connected to a jack chamber side oil passage of the first oil passage, and the other port is connected to the third oil passage. connected to a pump chamber side oil passage of the first oil path, to one port of the other oil path of the switching valve, to prevent the flow to the third oil passage from said pump chamber during the vehicle height up, Prevents the flow from the pump chamber to the jack chamber side oil path of the first oil path when the vehicle height decreases Rutotomo provided with a second check valve
The orifice is connected to one port of the other oil passage of the switching valve.
The second check valve forms the orifice
In the closing direction .

According to a second aspect of the present invention, in the first aspect of the present invention, the pump chamber and the oil reservoir are further connected via a second oil passage branched from an oil passage on the pump chamber side of the first oil passage. A first check valve communicating with the pump chamber and blocking the flow from the pump chamber to the oil reservoir is provided in the second oil passage.

According to a third aspect of the present invention, in the first or second aspect, a third check valve for preventing a flow from the hydraulic jack chamber to the pump chamber is provided on the jack chamber side of the first oil passage. The third check valve is provided in the oil passage, and is opened when the vehicle height decreases.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the relief valve is opened when the hydraulic pressure in the hydraulic jack chamber becomes a predetermined value or more. .

[0009]

According to a fifth aspect of the present invention, in the third or fourth aspect , a peripheral groove is formed on the outer periphery of the switching valve, and a tappet is provided between the outer periphery of the switching valve and the third check valve. When the vehicle height is increased, the tappet is located in the peripheral groove portion and closes the third check valve. When the vehicle height is decreased, the tappet is located in the outer peripheral portion where the peripheral groove is not formed and the third check valve is closed. The check valve is opened.

[0011]

[Action] below According to the present invention, there is effect of the. A vehicle height adjustment switching device is provided in a first oil passage that communicates a pump chamber and a hydraulic jack chamber in a cylinder, and one end is opened at an outer periphery of a hole provided in a body of the vehicle height adjustment switching device. An oil passage on the pump chamber side, an oil passage on the jack chamber side of the first oil passage, a third oil passage communicating with the oil reservoir, and a relief communicating with the oil reservoir via a relief valve. An oil passage is provided, and a switching valve having two oil passages, one oil passage and the other oil passage connected to each other, is rotatably inserted into a hole of the body of the vehicle height adjustment switching device, and the other of the switching valves is provided. In one port of the oil passage, the flow from the pump chamber to the third oil passage is blocked when the vehicle height rises, and the flow from the pump chamber to the jack room side oil passage of the first oil passage when the vehicle height decreases. A second check valve to block was provided.

Therefore, when the switching valve is set to the vehicle height-up state, one port of the other oil passage is connected to the third oil passage, and the second check valve provided in the other oil passage is provided with the hydraulic pressure. The hydraulic oil discharged from the pump chamber when the shock absorber is compressed is prevented from flowing from the third oil passage to the oil reservoir, and the hydraulic oil is flowed to the hydraulic jack chamber. As a result, the vehicle height can be increased.

When the switching valve is set to the vehicle height down state, one port of the other oil passage is connected to the jack chamber side oil passage of the first oil passage, and the other oil passage is provided in the other oil passage. The second check valve prevents the hydraulic oil discharged from the pump chamber from flowing to the hydraulic jack chamber, and allows the hydraulic oil to flow from the third oil passage to the oil reservoir. As a result, the hydraulic oil in the hydraulic jack chamber opens the second check valve and returns to the oil reservoir,
The vehicle height can be reduced. Also, the hydraulic oil discharged from the hydraulic shock absorber flows into the oil reservoir, so that the hydraulic shock absorber can be compressed.

The switching valve rotates in the hole of the vehicle height adjustment switching device to switch the above-mentioned many oil passages between the vehicle height-up state and the vehicle height-down state. The size of the vehicle height adjustment switching device can be reduced in comparison with a spool valve that switches the vehicle height. One port of the other oil passage of the switching valve
The orifice is formed in the switch valve so that the switching valve is
When set to, the hydraulic oil in the hydraulic jack
It gradually returns to the pump chamber or the oil reservoir via the orifice.
Therefore, when lowering the vehicle height from the up state,
Avoid sudden drop in height and improve maneuverability
Can be.

According to the invention of claim 2, the following is provided. Action effects
There is. The second oil passage connecting the pump chamber and the oil reservoir
One check valve is provided to extend the hydraulic shock absorber.
In some cases, hydraulic oil is sucked into the pump chamber from the oil reservoir and compressed.
During the stroke, hydraulic oil can be discharged to the vehicle height adjustment device.
Wear.

According to the third aspect of the invention, Action effects
There is. A third check is placed in the jack room side oil passage of the first oil passage
A lock valve is provided so that during the compression stroke of the hydraulic shock absorber
Hydraulic oil is sent to the hydraulic jack chamber, and the hydraulic
Blocking the backflow of hydraulic oil from the jack chamber to the pump chamber prevents vehicle height
Can be up.

Further, when the third check valve is set in the vehicle height down state, the third check valve can be opened to return hydraulic oil from the hydraulic jack chamber to the pump chamber or the oil sump chamber to lower the vehicle height. .

According to the invention of claim 4, the following is provided. Action effects
There is. The height of the vehicle is completed and the internal pressure of the hydraulic jack room
When the pressure exceeds a predetermined value, the relief valve opens.
Later, the hydraulic oil flows through the relief oil passage to the oil sump,
The shock absorber can be compressed.

[0019]

According to the fifth aspect of the invention, the following operation and effect can be obtained. A tappet was inserted between the outer periphery of the switching valve and the third check valve, and a circumferential groove was formed in a part of the outer periphery of the switching valve. The check valve can be opened in conjunction with the rotation of the switching valve via the tappet.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below 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.

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

The jack portion 10 on the rear wheel side, which forms 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. The plunger 13 is slidably mounted between the inner peripheral surface of the plunger case 12 and the outer peripheral surface of the sleeve, and the spring collar 8a connected to the end of the plunger 3 applies the spring by the pressure of the suspension spring 9. The end face of the receiver 8 is in contact. In this way, the rear-wheel-side hydraulic jack chamber B is formed between the plunger case 12 and the plunger 13.

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

The jack portion 25 of the front fork 20 which forms a part of the self-pump type vehicle height adjusting device,
A plunger case 26 attached to a fork bolt 22a fixed to the upper end of the inner cylinder 22, a plunger 28 slidably fitted in the plunger case, and having a through hole 27; And a rod 29 projecting from As a result, a front-wheel-side hydraulic jack chamber C is formed between the plunger case 26 and the plunger 28. The above-mentioned spring receiver 2 is attached to the tip of the rod 29.
3 are attached.

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. The self-pump type vehicle height adjustment switching device 30 is provided in the first oil passage 31.
Is provided at the rear lower portion of the seat of the motorcycle and can be operated in the riding posture.

As shown in FIG. 2 and FIG. 3, an oil tank 34 in which a free piston 33 is inserted is screwed to a main body 32 of the vehicle height adjustment switching device 30. Also serves as a member. One chamber E partitioned by the piston 33 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 at 31c. The oil passages 31b and 31c constitute a first oil passage. On the other hand, the first oil passages 31b, 31
In the second oil passage 36 (FIGS. 2 and 3) which intersects with the oil sump D at right angles to the oil sump D, the seat 38 is seated on the seat 37 by the spring 38 so that the oil sump D is always connected to the oil sump D. A first check valve 39 urged to close the opening is provided.

In the above-described valve mechanism 40 shown in FIG. 4, a ring-shaped check valve 43 is provided between the spacer 41 and the bottom piece 42, and the bottom piece 42
The holder 45 screwed into the body 32 is
The tip of the needle valve 46 which is screwed from the outside so as to be adjustable from outside forms a narrowed flow path in close proximity. The bottom piece 42 is further provided with a plurality of through holes 47 around the center hole 44, and when the check valve 43 is extended, the plurality of through holes 4 are formed.
7 is opened.

Further, the first passage 31d going downstream from the valve mechanism 40 is guided to the switching valve mechanism 50 via an oil passage 31e reaching the hydraulic jack chamber B of the rear cushion 1.
The switching valve mechanism 50 has a rotatable switching valve 51, in which two orthogonal oil passages 31h, 31
i (see FIG. 2 or FIG. 3). 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 has a 90
It is inserted into a hole in the main body 32 so as to be able to take two positions, a vehicle height up position and a vehicle height down position, by a rotation operation of turning by 90 degrees and returning by 90 degrees. 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 31e of the first oil passage 31. And the other port is set so as to face the downstream side 31k 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 connected to the oil passage 31i.
Is always closed by a spring 52a biased between a chrysant washer 52a whose outer periphery is crimped to the other port opening surface and a second check valve 53. When the oil passage 31i is set at the vehicle height increasing 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 to the orifice is a relief. Oil passage 6
6. When the vehicle is set at the vehicle height down position (FIG. 3), the orifice 31j faces the downstream side 31k of the first oil passage 31, and the port opposite to the orifice faces the upstream side 31e. A valve seat 59 (FIG. 2a) is formed at the downstream side of the small-diameter cylindrical hole 75 in the downstream 31k of the first oil passage 31, and a third check valve 56 is pressed by a spring 57 on this valve seat. ing. In the small-diameter cylindrical hole 75,
A cylindrical tappet 55 slidably inserted at one end into sliding contact with a circumferential groove 51a formed at 180 ° on the outer periphery of the switching valve 51 and opening and closing the third check valve 56 at the other end. I have. The reason for providing the circumferential groove 51a is that the switching valve 5
By providing ports that cross each other at 90 ° on the outer peripheral surface of 1,
In the case where the rotation operation of rotating the switching valve 51 to the right by 90 ° and returning it to 90 ° is mistakenly stopped at 45 ° in the middle-of course, a 90 ° rotation stopper for preventing this and Although the click mechanism is attached, the oil passage 31e is
When the state does not match with the port of the oil passage 31h or 31i of the switching valve, the hydraulic oil upstream of the oil passage 31e is in an oil lock state, the shock absorber cannot perform a shock absorbing motion, and a large impact load is applied. Will lead to the destruction of the shock absorber. In order to prevent this, the oil passage 31e and the relief oil passage 66 are formed to communicate with each other at any position within 90 °. As can be seen from FIG. 5, the tappet 55 includes an oil passage 311 passing through the center and an oil passage 3l.
It has a branch path 31m that is orthogonal to 1l and that opens on the cutout surface 55a of the tappet 55. Further, as shown in FIG. 1, the first oil passage 31k is connected to the hydraulic jack chamber B of the rear cushion on the rear wheel side from the pipe joint 58 provided in the oil passage 31n branched laterally through the oil passage 31g. Connected. According to the present invention, the oil passage 31n communicating with the front wheel side oil passage 31g is connected to the hydraulic jack chamber C of the front fork on the front wheel side by the oil passage 31g 'via the pipe joint 58'.

The oil passage 31k is, as shown in FIGS.
Also, it is connected to a blow valve 70 via a horizontal oil passage 68,
The blow valve 70 is connected to the oil reservoir D via oil passages 69 and 54. The blow valve 70 includes a spring 71
The ball 73 held by the guide holder 72 normally closes the valve seat, but when the hydraulic oil downstream of the third check valve 56 abnormally rises in pressure when the vehicle height is increased (FIG. 2),
It is provided as a safety circuit that opens against the spring 71 and returns this hydraulic oil to the oil reservoir.

When the vehicle height is increased, the jack portions 10 and 2
In order to return the oil in the cylinder oil chamber A of the rear cushion 1 to the oil chamber D of the oil tank 34 when the internal pressure of the hydraulic jack chambers B and C of the fifth oil tank 5 becomes equal to or higher than a predetermined value, the relief valve 60 is used.
(FIG. 2 or FIG. 3) are provided in the bypass passages of the first oil passage connecting the jack portion of the rear cushion 1 to the oil chamber A of the rear cushion 1, respectively. That is, the relief valve 60 includes a valve body 62 slidably inserted into a hole 61 provided in the main body 32 and a spring 63 for urging the valve body toward the oil reservoir D of the oil tank 34. The hole 61 has a large diameter at the base end and a small diameter at the tip end facing the oil passage 65 formed in the main body 32, and a step is formed on the opening surface of the oil passage 65. A valve seat 62 ′ is formed by the tip of the valve body 62 abutting on the valve body 62. The valve body 62 normally blocks communication between the relief oil passage 66 formed in the main body 32 and the oil passage 65 by the urging force of the spring 63. Further, the valve body 62 has a small diameter at the distal end and a large diameter at the proximal end, and is urged by a spring 63 toward the valve seat in the hole 61. An oil chamber F is formed between the small-diameter portion and a pilot oil passage 64 of the main body 32 communicating with the jack chamber.

The vehicle height adjusting operation of the self-pump type vehicle height adjusting device for the hydraulic shock absorber configured as described above will be described. When traveling in an urban area, the switching valve 51 is set to the third position.
Switch to the vehicle height down position as shown. During traveling, when the piston 4 enters the cylinder 3 during the compression stroke of the rear cushion 1, oil flows from the pump chamber A through the hole of the piston 4, pushes up the valve 4a and flows into the oil chamber on the opposite side. Generates compression-side damping force. At the same time, the oil in the pump chamber A corresponding to the intrusion volume of the piston rod is supplied to the first oil passage 31a
Enter from 31b. Since the first check valve 39 (FIG. 2) of the second oil passage 36 branched from the first oil passage 31b and communicating with the oil reservoir D is closed, the first oil passage 31c is further closed. Flows through the oil passage 44 (FIG. 4) into the valve mechanism 40 that generates a compression-side damping force through the needle valve 46.
A compression-side damping force is generated by the narrowed flow path. Further, the oil that has exited the valve mechanism 40 is supplied from the first oil passage 31d to the oil passage 31i of the switching valve 51 of the switching valve mechanism 50 via the 31e.
(FIG. 3), but flows into the oil reservoir D of the oil tank 34 via the third oil passage 54 because the oil passage to the jack portion is closed by the second check valve 53. The gas chamber E performs volume compensation accompanying the intrusion and penetration of the piston rod. In the extension stroke, the oil in the pump chamber A passes through the oblique hole of the piston 4, pushes up the valve 4b, flows into the pump chamber A, and generates an extension-side damping force. This pump room A
From the oil reservoir D of the oil tank 34 through the first check valve 39 (FIG. 3) opened by the decompression in the pump chamber A and the second oil. Oil passage 36, first oil passage 31b, pipe joint 35,
The oil flows into the pump chamber A of the rear cushion 1 via the oil passage 31a, and is directly and quickly replenished. Further, the oil in the jack chambers B and C of the rear cushion 1 and the front fork 20 also passes through the switching valve 51 as described later, and the compression side damping valve mechanism 4
The check valve 43 closing the plurality of through-holes 47 of the bottom piece 42 of FIG.

When the vehicle starts traveling on a rough terrain, the switching valve 51 is set to the first position.
When the vehicle is switched to the vehicle height increasing position shown in FIG. 2 or FIG. 2, the oil corresponding to the volume of the piston rod intruding during the compression stroke of the rear cushion 1 is transferred from the oil chamber A to the first oil passages 31 a and 31.
b, 31c (FIG. 1), enters the valve mechanism 40 and is throttled by the needle valve 46 to generate a compression-side damping force. Further, the oil flows from the first oil passage 31d through the oil passage 31e to the switching valve 51. Through the oil passage 31h, and the central oil passage 3 of the tappet 55
1i, the third check valve 56 is further connected to the spring 5
The oil in the pump chamber A flows through the oil passage 3k until it reaches the valve opening pressure of the relief valve 62 by being pressed against the oil passage 31 to reach the valve opening pressure of the relief valve 62.
The oil flows into the hydraulic jack chamber B of the rear cushion 1 and the hydraulic jack chamber C of the front fork 20 via oil passages 31g and 31g 'communicating with each other by 1n.
In this case, since the front-wheel jack chamber B and the rear-wheel jack chamber C communicate with each other, the hydraulic oil can freely flow between them, and the vehicle body can perform a pitching motion. The action is promoted, and the vehicle height rise time is shortened. When the pressure of the hydraulic oil flowing from the inside of the pump chamber A of the rear cushion 1 further increases and reaches the valve opening pressure of the blow valve 70, the pressure oil pushes down the ball of the blow valve 70 and also flows into the oil reservoir D. .

During the extension stroke of the rear cushion 1 with the switching valve 51 switched to the vehicle height increasing position as described above, the pressure in the pump chamber A is reduced by the piston rod retreating out of the cylinder. The third check valve 56 is sucked, the opposite valve seat 59 on the opposite side is closed, and the oil in the jack portion of the rear cushion 1 and the front fork 20 cannot flow backward. Since the first check valve 39 is opened, the oil in the oil reservoir D of the oil tank 34 flows directly into the pump chamber A of the rear cushion 1 via the second oil passage 36 and the first oil passages 31b and 31a. To quickly compensate for the volume of oil lost by the piston rod. By repeating the compression and extension strokes of the rear cushion 1 as described above, a self-pumping action is performed through the action of the third check valve 56, and oil is generated between the rear cushion 1 and the front fork 20 every compression stroke of the rear cushion. Guided to jack chambers B and C, the suspension springs 9 and 24 are gradually compressed. When the internal pressures of the jack chambers B and C exceed a predetermined value, the high-pressure oil acts on the oil chamber F through the pilot oil passage 64 (FIG. 2), and the valve body 62 of the relief valve 60 springs upward in FIG. 63 against the valve body 62
Is separated from the valve seat 62b, the oil in the cylinder pump chamber A of the rear cushion 1 is returned from the relief oil passage 66 to the oil reservoir D of the oil tank 34 through the oil passage 65.

In this manner, the suspension springs 9 and 24 are gradually compressed, but 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. As a result, the suspension spring load increases, and the vehicle body is pushed up to increase the vehicle height.

When the switching valve 51 is rotated to switch to the vehicle height down position shown in FIG. 3 when the vehicle enters the city from the rough terrain, the tappet 55 is pushed up by the outer peripheral portion of the switching valve 51. Connect the third check valve 56 to the valve seat 5
Remove from 9. Then, the high pressure oil in the hydraulic jack chambers B and C of the rear cushion 1 and the front fork 20 passes through the outer periphery of the third check valve 56 which is open, and the cutout surface 55a of the tappet 55 in the axial outer periphery.
The radial oil passage 31m drilled in the tappet (FIG. 5) from the passage defined on the inner periphery of the small-diameter cylindrical hole by
After passing through 1l, it passes through the orifice 31j of the switching valve 51, presses and opens the second check valve 53 interposed in the switching valve 51 against the spring 52, and the oil passage 31h of the switching valve 51 is opened.
Flows into the oil reservoir D through the third oil passage 54 of the main body 32. As a result, the oil in the jack chambers B and C of the rear cushion 1 and the front fork 20 is drained, so that the plungers 13 and 28 retreat, respectively, so that the vehicle height decreases. At this time, the other oil passage 3 of the switching valve 51
1i has an orifice 31j in one port
When the switching valve 51 is set to the vehicle height down state,
The hydraulic oil in the hydraulic jack passes through this orifice 31j.
To gradually return to the pump chamber A or the oil reservoir D. Therefore, the car
When lowering the height from the up state, the vehicle height suddenly increases
It is possible to prevent the vehicle from lowering and improve the maneuverability.

[0038]

As described above, according to the present invention, the vehicle hydraulic shock absorber having the vehicle height adjustment switching device capable of appropriately changing the vehicle height according to the traveling road surface and reducing the size. in the self-pumped vehicle height adjusting device, the vehicle height
The vehicle height drops sharply when
It is possible to avoid falling and improve the maneuverability.

[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 self-pump type vehicle height adjusting device according to the present invention, in which a switching valve of the self-pump type vehicle height adjusting device is switched to a vehicle height increasing position. It is a longitudinal section showing a state.

FIG. 2 is a partial cross-sectional view of the self-pump type vehicle height adjustment device taken along a line II-II in FIG. 1; FIG. 2a is an enlarged view of the vicinity of the switching valve, tappet, and third check valve of FIG.

FIG. 3 is a partial sectional view similar to FIG. 2, but showing a state in which a switching valve is switched to a vehicle height down position.

FIG. 4 is a partial sectional view showing a valve mechanism of the self-pump type vehicle height adjusting / changing device of FIG. 1;

FIG. 5 is a perspective view of a tappet adjacent to a switching valve of the self-pump type vehicle height adjustment switching device.

FIG. 6 is a schematic hydraulic circuit diagram for a rear cushion and a front fork having a self-pump type vehicle height adjusting device according to the present invention, showing a state in which a vehicle height increasing position is switched.

[Explanation of symbols]

 Reference Signs List A pump chamber in cylinder B rear-wheel hydraulic jack chamber C front-wheel hydraulic jack chamber D oil reservoir 1 rear cushion (hydraulic shock absorber) 3 cylinder 6 piston rod 10 jack part 20 front fork (hydraulic shock absorber) 25 jack part Reference Signs List 30 vehicle height adjustment switching device 31 first oil passage 31h, 31i two oil passages 31j orifice 32 main body 36 second oil passage 39 first check valve 51 switching valve 53 second check valve 54 third oil passage 55 tappet 56 third check valve 60 relief valve 66 relief oil passage

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62K 25/00-25/32 B60G 17/00-17/08 F16F 9/50

Claims (5)

(57) [Claims] The vehicle height is adjusted by adjusting a distance between a vehicle body and an axle, a piston rod that moves in and out of a cylinder of a hydraulic shock absorber, a pump chamber formed in the cylinder, an oil reservoir that communicates with the pump chamber. The hydraulic oil in the oil sump chamber is supplied to the hydraulic jack chamber of the jack part through the pump chamber to enable the vehicle height to be increased, and the hydraulic oil in the hydraulic jack chamber is adjusted. In the self-pump type vehicle height adjustment device that adjusts the vehicle height by returning the vehicle to the oil sump chamber, wherein the first oil passage communicating the pump chamber in the cylinder with the hydraulic jack chamber is provided. A vehicle height adjustment switching device is interposed, a rotatable switching valve is housed in a hole provided in the body of the vehicle height adjustment switching device, and a pump chamber side oil passage of the first oil passage and the first oil passage. To the jack chamber side oil passage of the oil passage and the oil reservoir. A third oil passage, and a relief oil passage for returning oil in a pump chamber to the oil reservoir via a relief valve are opened in the switching valve housing surface of the hole, and the switching valve is connected to one oil passage. It has two oil passages of the other oil passage, the two oil passages are connected to each other, and each has two ports. When the vehicle height is increased, one port of one oil passage of the switching valve is connected to the other oil passage. The other port is connected to the pump chamber side oil path of the first oil path, the other port is connected to the third oil path, and the other port is connected to the relief port. When the vehicle height is reduced, one port of one oil path of the switching valve is connected to the third oil path, the other port is connected to the relief oil path, and one port of the other oil path is connected. Port is the jack chamber side oil path of the first oil path, and the other port is the first oil path of the first oil path. Is connected to the pump chamber side oil passage, said pump to one port of the other oil path of the switching valve, to prevent the flow of the third oil passage from said pump chamber during the vehicle height up, when the vehicle height down the second check valve provided Rutotomoni which prevents flow from the chamber to the first oil path jack chamber side oil passage, one port of the other oil path of the switching valve
An orifice in the second check valve
Is a self-pump type vehicle height adjusting device provided in a direction to close the orifice . 2. The pump chamber communicates with the oil reservoir via a second oil passage branched from an oil passage on the pump chamber side of the first oil passage. A first check valve for preventing flow is provided in a second oil passage.
The self-pump type vehicle height adjusting device according to the above. 3. A third check valve for preventing a flow from the hydraulic jack chamber to the pump chamber side is provided in a jack chamber side oil path of a first oil path, and the third check valve is configured to reduce a vehicle height. 3. The self-pump type vehicle height adjusting device according to claim 1, wherein the valve is sometimes opened. 4. The relief valve opens when the hydraulic pressure in the hydraulic jack chamber becomes equal to or higher than a predetermined value.
The self-pump type vehicle height adjustment device according to any one of the above. 5. A peripheral groove is formed on the outer periphery of the switching valve, and a tappet is inserted between the outer periphery of the switching valve and the third check valve. And closing the third check valve when the vehicle height is lowered, and opening the third check valve at an outer peripheral portion where the peripheral groove is not formed when the vehicle height is lowered.
Is a self-pump type vehicle height adjusting device according to 4.