Shock absorber provided with vehicle height adjustment function

Abstract

A shock absorber (D) provided with a vehicle height adjustment function comprises: a shock absorber body (A); a pump chamber (P) that expands and contracts as the shock absorber body (A) expands and contracts; a tank (T); a suspension spring (S) interposed between a movable spring receiver (10) and a fixed spring receiver (7c); a jack (J); a suction passage (20) through which the tank (T) and the pump chamber (P) communicate; a discharge passage (21) connected to the pump chamber (P); a supply / discharge passage (22) connected to the jack chamber (C); a return passage (23) connected to the tank (T); and a switching valve (V) that has a supply position (30a) at which the discharge passage (21) and the supply / discharge passage (22) communicate with each other and the return passage (23) is blocked, an unload position (30b) at which the discharge passage (21) and the return passage (23) communicate with each other and the supply / discharge passage (22) is blocked, and a discharge position (30c) at which the discharge passage (21), the supply / discharge passage (22), and the return passage (23) all communicate with each other.

Description

shock absorber with vehicle height adjustment function

[0001] The present invention relates to a shock absorber with a vehicle height adjustment function.

[0002] A shock absorber with a vehicle height adjustment function is used, for example, by being interposed between the body and wheels of a saddle-ride type vehicle, and suppresses vibrations between the body and wheels by the damping force generated when the shock absorber expands and contracts, and also adjusts the vehicle height.

[0003] Such a shock absorber with vehicle height adjustment function includes, for example, a cylinder, a piston that is movably inserted into the cylinder and divides the cylinder into an extension side chamber and a compression side chamber filled with hydraulic oil, a cylindrical piston rod that is movably inserted into the cylinder and connected to the piston, a tank that stores hydraulic oil, a cylindrical housing attached to the outer periphery of the cylinder, a movable spring bearing that is movably inserted into the housing in the axial direction and forms a jack chamber between it and the housing, a suspension spring interposed between the movable spring bearing and a spring bearing provided at the tip of the piston rod, and a pump rod that is inserted into the compression side chamber and the piston rod and forms a pump chamber that, together with the piston rod, is connected to the jack chamber.

[0004] When a shock absorber with vehicle height adjustment function configured in this manner expands and contracts due to vibrations input when a saddle-type vehicle is traveling, as shown in JP2008-128427A, the pump chamber also expands and contracts in accordance with the displacement of the piston rod relative to the cylinder, and the pump chamber sucks in hydraulic oil from the cylinder and discharges it into the jack chamber, pushing the movable spring holder out of the jack chamber and raising the vehicle height.

[0005] JP2008-128427A

[0006] Conventional shock absorbers with height adjustment functions use the expansion and contraction of the pump chamber during travel of a saddle-type vehicle to automatically raise the vehicle height to a specified height, and are therefore advantageous in that they do not require a drive source to raise the vehicle height. However, when the vehicle height is raised, the pressure in the pump chamber is constantly increased to the same pressure as the jack chamber, which creates resistance and increases the compression damping force generated during the contraction operation.

[0007] Therefore, in conventional shock absorbers with a vehicle height adjustment function, the damping force during the contraction operation is high, which often causes a saddle-ride type vehicle occupant to feel a rough feeling, and therefore there is a demand for improved ride comfort.

[0008] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a shock absorber with a vehicle height adjustment function that can adjust the vehicle height in accordance with the expansion and contraction operation and can improve the riding comfort of the vehicle.

[0009] In order to solve the above-mentioned problems, the shock absorber with vehicle height adjustment function of the present invention comprises a shock absorber body having a cylinder, a piston rod inserted into the cylinder so as to be movable in the axial direction, a piston connected to the piston rod and inserted into the cylinder so as to be movable in the axial direction, and dividing the inside of the cylinder into an extension-side chamber and a compression-side chamber, a pump chamber that expands and contracts as the shock absorber body expands and contracts, a tank for storing liquid, a suspension spring interposed between a movable spring bearing arranged on the outer periphery of the cylinder so as to be movable in the axial direction and a fixed spring bearing attached to the piston rod, and a jack chamber for supplying and discharging fluid into and from the jack chamber. the pump includes a jack that can displace a movable spring bearing relative to the cylinder by the liquid being pumped into it; a suction passage that only allows the flow of liquid from the tank to the pump chamber; a discharge passage connected to the pump chamber; a supply / discharge passage connected to the jack chamber; a return passage connected to the tank; and a switching valve that has a supply position that only allows the flow of liquid from the discharge passage to the supply / discharge passage and blocks the return passage; an unload position that connects the discharge passage and the return passage and blocks the supply / discharge passage; and a discharge position that connects the discharge passage, the supply / discharge passage, and the return passage to each other.

[0010] With this height-adjustable shock absorber, when the switching valve is set to the supply position, liquid is supplied from the pump chamber to the jack chamber to raise the vehicle height, and when the switching valve is set to the unload position, the communication between the pump chamber and the jack chamber is cut off, maintaining the vehicle height while connecting the pump chamber to the tank, so that even if the shock absorber body expands or contracts, pressure in the pump chamber does not increase, and further, when the switching valve is set to the discharge position, the pump chamber, jack chamber and tank are connected to each other, making it possible to lower the vehicle height.

[0011] Fig. 1 is a cross-sectional view of a shock absorber with a vehicle height adjustment function according to an embodiment of the present invention, and Fig. 2 is a diagram showing a specific example of a switching valve of the shock absorber with a vehicle height adjustment function according to an embodiment of the present invention.

[0012] The present invention will be described below based on the embodiment shown in the drawings. As shown in Fig. 1, a shock absorber D with a vehicle height adjustment function in one embodiment includes a cylinder 1, a piston rod 2 inserted into the cylinder 1 so as to be movable in the axial direction, a shock absorber body A including a piston 3 connected to the piston rod 2 and inserted into the cylinder 1 so as to be movable in the axial direction, and dividing the cylinder 1 into an extension-side chamber R1 and a compression-side chamber R2, a pump chamber P which expands and contracts as the shock absorber body A expands and contracts, a tank T for storing liquid, a suspension spring S interposed between a movable spring bearing 10 arranged on the outer periphery of the cylinder 1 so as to be movable in the axial direction and a fixed spring bearing 7c attached to the piston rod 2, and a jack chamber C which is movably supplied and discharged into and from the jack chamber C. The hydraulic pump is provided with a jack J capable of displacing the moving spring bearing 10 relative to the cylinder 1, a suction passage 20 that allows only the flow of liquid from the tank T toward the pump chamber P, a discharge passage 21 connected to the pump chamber P, a supply / discharge passage 22 connected to the jack chamber C, a return passage 23 connected to the tank T, a supply position 30a that allows only the flow of liquid from the discharge passage 21 toward the supply / discharge passage 22 and blocks the return passage 23, an unload position 30b that connects the discharge passage 21 and the return passage 23 and blocks the supply / discharge passage 22, and a discharge position 30c that connects the discharge passage 21, the supply / discharge passage 22, and the return passage 23 to one another.

[0013] Although not shown, this shock absorber D with height adjustment function is used by being interposed between the body and rear wheel of a saddle-ride type vehicle such as a motorcycle, and suppresses vibration of the body and the rear wheel. Note that the shock absorber D with height adjustment function may also be used in vehicles other than saddle-ride type vehicles.

[0014] The following describes in detail each part of the shock absorber D with vehicle height adjustment function. First, the following describes each part of the shock absorber main body A. As shown in Figure 1, the cylinder 1 is cylindrical, and the upper end in Figure 1 is closed by a rod guide 5, and the lower end in Figure 1 is closed by a cap 6.

[0015] 1 is annular, and includes an annular seal ring 5a on its outer periphery that tightly contacts the inner periphery of the cylinder 1, and an annular seal ring 5b and an annular bushing 5c ​​on its inner periphery that slide against the outer periphery of the piston rod 2. The rod guide 5 is restricted from moving upward in FIG. 1 relative to the cylinder 1 by a C-ring 40 that is attached to the inner periphery of the upper end of the cylinder 1 in FIG.

[0016] The piston rod 2, which is movably inserted into the cylinder 1, is inserted through the seal ring 5b and bushing 5c ​​of the rod guide 5 attached to the inner periphery of the cylinder 1 in this manner. The rod guide 5 supports the piston rod 2 with the bushing 5c ​​to guide the axial movement of the piston rod 2 relative to the cylinder 1, and seals the outer periphery of the piston rod 2 with the seal ring 5b. In addition, a seal ring 5a is in close contact with the inner periphery of the cylinder 1, preventing leakage of liquid from between the rod guide 5 and the cylinder 1. The upper end in FIG. 1, which is the tip of the piston rod 2, protrudes outward from the upper end of the cylinder 1 in FIG. 1, via the inner periphery of the rod guide 5.

[0017] The piston rod 2 is cylindrical and includes a small-diameter portion 2a at its lower end in Fig. 1, the outer diameter of which is smaller than that of its upper portion, and on whose outer periphery the piston 3 is attached, a threaded portion 2b at the outer periphery of the small-diameter portion 2a at its lower end in Fig. 1, and a through-hole 2c that radially penetrates a side portion above the small-diameter portion 2a in Fig. 1. A bracket 7 that can be connected to the body of a saddle-ride type vehicle is attached to the upper end of the piston rod 2 in Fig. 1.

[0018] Next, a piston 3 attached to a piston rod 2 is inserted into the cylinder 1 so as to be axially movable, and the inside of the cylinder 1 is divided by the piston 3 into an extension-side chamber R1 above the piston 3 and a compression-side chamber R2 below the piston 3. The extension-side chamber R1 and the compression-side chamber R2 are filled with a liquid such as hydraulic oil. Note that although the liquid is hydraulic oil in this embodiment, it may be a liquid other than hydraulic oil, such as water or an aqueous solution. The through-hole 2c of the piston rod 2 opens above the small-diameter portion 2a on which the piston 3 is attached in FIG. 1 and faces the extension-side chamber R1, so that the inside of the piston rod 2 is in communication with the extension-side chamber R1 via the through-hole 2c.

[0019] The piston 3 is annular and attached to the outer periphery of the small diameter portion 2a of the piston rod 2, and is provided with an extension-side port 3a and a compression-side port 3b that respectively communicate in parallel with the extension-side chamber R1 and the compression-side chamber R2. An annular extension-side damping valve 13 that is attached to the outer periphery of the small diameter portion 2a and opens and closes the extension-side port 3a is stacked at the lower end of the piston 3 in FIG. 1. Also, an annular compression-side damping valve 14 that is attached to the outer periphery of the small diameter portion 2a and opens and closes the compression-side port 3b is stacked at the upper end of the piston 3 in FIG. 1. The piston 3, the extension-side damping valve 13, and the compression-side damping valve 14 are fitted onto the outer periphery of the small diameter portion 2a of the piston rod 2, and are fixed to the piston rod 2 by a piston nut 15 that is threaded onto the lower end of the small diameter portion 2a.

[0020] In the height adjustable shock absorber D of this embodiment, the extension-side damping valve 13 is a laminated leaf valve configured by stacking multiple annular plates on the lower end of the piston 3 in FIG. 1 , with the inner circumferential side fixed and the outer circumferential side deflected by the pressure in the extension-side chamber R1, thereby opening the extension-side port 3a. The extension-side damping valve 13 is capable of opening and closing the extension-side port 3a, and opens when the height adjustable shock absorber D expands to provide resistance to the flow of fluid passing through the extension-side port 3a from the expansion-side chamber R1 to the compression-side chamber R2, and closes when the height adjustable shock absorber D contracts to block the extension-side port 3a. Note that the extension-side damping valve 13 may be a damping valve other than a laminated leaf valve as long as it is a damping valve that provides resistance to the flow of fluid from the expansion-side chamber R1 to the compression-side chamber R2 and can exert a damping force that prevents the extension of the height adjustable shock absorber D when the height adjustable shock absorber D expands.

[0021] In contrast, in the height adjustable shock absorber D of this embodiment, the compression side damping valve 14 is a stacked leaf valve configured by stacking multiple annular plates on the upper end of the piston 3 in FIG. 1 , with the inner circumferential side fixed and the outer circumferential side deflected by the pressure in the compression side chamber R2, which opens the compression side port 3b. The compression side damping valve 14 is capable of opening and closing the compression side port 3b, and opens when the height adjustable shock absorber D contracts to provide resistance to the flow of fluid passing through the compression side port 3b from the compression side chamber R2 to the expansion side chamber R1, and closes to block the compression side port 3b when the height adjustable shock absorber D expands. Note that the compression side damping valve 14 may be a damping valve other than a stacked leaf valve as long as it is a damping valve that provides resistance to the flow of fluid from the compression side chamber R2 to the expansion side chamber R1 and can exert a damping force that prevents the height adjustable shock absorber D from contracting when the height adjustable shock absorber D contracts. Although not shown, orifices are provided in parallel with the extension side damping valve 13 and the compression side damping valve 14. The orifices are formed, for example, by notches provided in annular plates that constitute the extension side damping valve 13 and the compression side damping valve 14, or by stampings provided on the valve seats of the piston 3 on which the annular plates sit and move away from each other.

[0022] In this way, the expansion side port 3a and the compression side port 3b of the piston 3 communicate with the expansion side chamber R1 and the compression side chamber R2. Furthermore, when the extension side damping valve 13 and the compression side damping valve 14 are closed, the orifice provides resistance to the flow of fluid passing through the expansion side port 3a and the compression side port 3b and going back and forth between the expansion side chamber R1 and the compression side chamber R2, and when the extension side damping valve 13 and the compression side damping valve 14 are open, the extension side damping valve 13 provides resistance to the flow of fluid passing through the expansion side port 3a, and the compression side damping valve 14 provides resistance to the flow of fluid passing through the compression side port 3b.

[0023] The cap 6 that closes the lower end of the cylinder 1 in Figure 1 includes a cap body 6a that is continuous with the lower end of the cylinder 1 and closes the lower end of the cylinder 1, a bracket 6b that is provided at the lower end of the cap body 6a and can be connected to a swing arm (not shown) that supports the rear wheel of a saddle-ride type vehicle, a valve housing 6c that is provided on the side of the cap body 6a, and a tank holding portion 6d that is also provided on the side of the cap body 6a and holds the tank T.

[0024] The tank T includes a cylindrical container 16 provided above the tank holding portion 6d in FIG. 1, a plug 17 attached to the inner periphery of the upper end of the container 16 in FIG. 1 to close the opening of the container 16, and a diaphragm 18 sandwiched between the container 16 and the plug 17 to form an air chamber G in the container 16 that is filled with gas and a liquid chamber L in the container 16 that is filled with liquid.

[0025] The cap 6 is provided with a discharge passage 24 and a tank passage 25 that open from the upper end of the cap body 6a facing the compression-side chamber R2 and communicate with the upper end of the tank holding portion 6d facing the liquid chamber L. The cap 6 also includes a base valve 26 that is provided in the discharge passage 24 and provides resistance to the flow of liquid from the compression-side chamber R2 to the liquid chamber L, and a suction check valve 27 that is provided in the tank passage 25 and allows only the flow of liquid from the liquid chamber L to the compression-side chamber R2.

[0026] The shock absorber body A is connected to the body of the saddle-ride type vehicle via a bracket 7 provided at the upper end of the piston rod 2 in Figure 1, and may also be connected to the rear wheel of the saddle-ride type vehicle via a bracket 6b of the cap 6, and may be interposed between the body and the rear wheel, or conversely, the bracket 7 may be connected to the rear wheel, and the cap 6 may be connected to the body.

[0027] In the shock absorber body A configured as described above, during an extension operation in which the piston rod 2 retracts from the cylinder 1, the liquid moves through the extension-side port 3a from the extension-side chamber R1, which is reduced by the piston 3 displacing together with the piston rod 2, to the compression-side chamber R2, which is expanded, and resistance is applied to the flow of the liquid by the extension-side damping valve 13, generating an extension-side damping force that hinders the extension operation. To make up for the liquid shortage in the cylinder 1 caused by the retraction of the piston rod 2 from the cylinder 1, the suction check valve 27 opens and the liquid is supplied from the liquid chamber L of the tank T through the tank passage 25 into the cylinder 1.

[0028] On the other hand, when the shock absorber main body A is in a contracting operation in which the piston rod 2 enters the cylinder 1, the compression-side damping valve 14 provides resistance to the flow of liquid as it moves through the compression-side port 3b from the compression-side chamber R2, which is reduced by the piston 3 displacing together with the piston rod 2, to the expansion-side chamber R1. Also, when the piston rod 2 enters the cylinder 1 and excess liquid in the cylinder 1 moves through the discharge passage 24 to the liquid chamber L of the tank T, the base valve 26 provides resistance to the flow of liquid. Therefore, when the shock absorber main body A is in a contracting operation, the compression-side damping valve 14 and the base valve 26 provide resistance to the flow of liquid, generating a compression-side damping force that hinders the contraction of the shock absorber main body A. Therefore, the height-adjustable shock absorber D can generate a damping force as the shock absorber main body A expands and contracts, thereby suppressing vibration of the vehicle body.

[0029] Next, a pump chamber P, which expands and contracts as the shock absorber body A expands and contracts, is formed by the pump rod 4 and the piston rod 2 held by the cap body 6 a of the cap 6 .

[0030] The cap body 6a has a recess 6a1 at the center of its upper end in Fig. 1, into which the lower end of the cylindrical pump rod 4 in Fig. 1 is inserted. A retaining ring 28 is provided in the recess 6a1 to prevent the pump rod 4 from slipping out of the recess 6a1, thereby holding the pump rod 4 in place in the cap 6. A seal ring 29 that tightly contacts the outer periphery of the pump rod 4 is also provided in the recess 6a1, providing a seal between the cap 6 and the outer periphery of the pump rod 4.

[0031] The pump rod 4 extends from the cap main body 6a of the cap 6 and is inserted into the compression-side chamber R2, and is slidably inserted into the piston rod 2. More specifically, the outer diameter of the pump rod 4 is smaller than the inner diameter of the piston rod 2, and the pump rod 4 is slidably inserted into a cylindrical bushing 2d attached to the inner periphery of the lower end of the small-diameter portion 2a of the piston rod 2 in FIG. 1. Therefore, when the shock absorber main body A expands and contracts and the piston rod 2 displaces relative to the cylinder 1, the piston rod 2 also displaces relative to the pump rod 4 held by the cap 6. The pump rod 4 and the piston rod 2 form a pump chamber P therein, and when the shock absorber main body A expands and contracts, the pump rod 4 and the piston rod 2 move relative to each other in the axial direction, thereby expanding and contracting the volume of the pump chamber P.

[0032] The pump rod 4 is loosely fitted in the recess 6a1, and although it is held in the cap 6 by a retaining ring 28, a slight radial vibration is permitted at the upper end in Fig. 1, and when inserted into the piston rod 2, it can smoothly advance and retreat within the piston rod 2, following the movement of the piston rod 2. As described above, the pump chamber P is provided within the shock absorber main body A by the piston rod 2 which is cylindrical, and the pump rod 4 which advances and retreats within the piston rod 2 as the shock absorber main body A expands and contracts. Therefore, the pump chamber P can be installed without increasing the size of the shock absorber main body A, but the pump chamber P may also be provided outside the shock absorber main body A.

[0033] Next, the bracket 7 attached to the upper end of the piston rod 2 includes a U-shaped connecting portion 7a that is connected to the vehicle body, a cup-shaped retaining ring 7b attached to the lower end of the connecting portion 7a in FIG. 1, and an annular fixed spring bearing 7c attached to the outer periphery of the lower end of the retaining ring 7b in FIG. 1. The retaining ring 7b holds the upper end of a cylindrical cushion rubber 41 that fits onto the outer periphery of the upper end of the piston rod 2. The fixed spring bearing 7c includes an annular seat portion 7c1 and a cylindrical portion 7c2 that extends downward from the inner periphery of the seat portion 7c1 and fits onto the outer periphery of the retaining ring 7b, and is fixed to the retaining ring 7b. Although the fixed spring bearing 7c is integral with the bracket 7, it may be attached to the piston rod 2 separately from the bracket 7.

[0034] The cushion rubber 41 faces the bump stopper 42 axially, which is attached to the upper end of the cylinder 1 in FIG. 1, and when the shock absorber D with vehicle height adjustment function contracts to the vicinity of the stroke end, it comes into contact with the bump stopper 42 and is compressed, thereby exerting a resilient force to mitigate the impact when the shock absorber D with vehicle height adjustment function contracts to the maximum extent.

[0035] A jack J that drives a movable spring bearing 10 is provided on the outer periphery of the cylinder 1, at the lower side in Figure 1. The jack J includes a cylindrical housing 8 attached to the outer periphery of the cylinder 1, and a plunger 9 that slides between the inner periphery of the housing 8 and the outer periphery of the cylinder 1, moving in and out of the housing 8 to form a jack chamber C together with the housing 8. The housing 8 is annular and includes a bottom portion 8a that fits onto the outer periphery of the cylinder 1, and a cylindrical portion 8b that rises upward in Figure 1 from the outer periphery of the bottom portion 8a. A seal ring 8c that fits tightly against the outer periphery of the cylinder 1 is housed in an annular groove (not shown) provided on the inner periphery of the bottom portion 8a, and an annular dust seal 8d and a seal ring 8e are attached to the inner periphery of the open end of the cylindrical portion 8b, in that order from the atmosphere side.

[0036] Furthermore, a plunger 9 is mounted on the outer periphery of the cylinder 1 so as to be axially movable. The plunger 9 is inserted into the cylindrical portion 8b of the housing 8 and forms a jack chamber C within the cylindrical portion 8b together with the housing 8. The plunger 9 is cylindrical and comes into sliding contact with the outer periphery of the cylinder 1 and the inner periphery of the cylindrical portion 8b of the housing 8 to define the jack chamber C within the cylindrical portion 8b. The plunger 9 has an annular protrusion 9a that protrudes upward from the inner periphery at the upper end, and is also provided on its inner periphery with an annular dust seal 9b, a bushing 9c, and a seal ring 9d that come into sliding contact with the outer periphery of the cylinder 1, in that order from the atmosphere side.

[0037] When plunger 9 is inserted into cylindrical portion 8b of housing 8, dust seal 8d and seal ring 8e provided on the inner periphery of cylindrical portion 8b slide against the outer periphery of plunger 9, and dust seal 9b, bushing 9c, and seal ring 9d provided on the inner periphery of plunger 9 slide against the outer periphery of cylinder 1, thereby sealing jack chamber C. The plunger 9 is movable in the vertical direction in FIG. 1 relative to cylinder 1 and housing 8, and can move up and down within a range from a position where its lower end abuts against bottom portion 8a to maximize compression of jack chamber C to a position where it abuts against stopper ring 70 fixed to the outer periphery of cylinder 1 and is restricted from moving upward relative to housing 8. An annular recess 9e is provided on the inner periphery of the lower end of plunger 9 to prevent the lower end surface of plunger 9 from coming into close contact with the entire upper surface of bottom portion 8a when the lower end of plunger 9 abuts against bottom portion 8a to minimize the volume of jack chamber C. This prevents the plunger 9 from sticking to the bottom portion 8a, ensuring smooth movement of the plunger 9.

[0038] A movable spring bearing 10 having an annular shape and an L-shaped cross section is fitted to the outer periphery of a protrusion 9a provided at the upper end of the plunger 9. The movable spring bearing 10 includes an annular seat portion 10a that axially faces the seat portion 7c1 of the fixed spring bearing 7c, and a cylindrical guide portion 10b that rises upward in FIG. 1 from the inner periphery of the seat portion 10a and is fitted to the outer periphery of the protrusion 9a, and is radially aligned with the cylinder 1 by being fitted to the protrusion 9a. The movable spring bearing 10 seats the seat portion 10a on the outer periphery of the protrusion 9a at the upper end of the plunger 9, and can move together with the plunger 9 in the up-down direction in FIG. 1, which is the axial direction, relative to the cylinder 1. Although the movable spring bearing 10 is separate from the plunger 9, it may be provided integrally with the plunger 9.

[0039] A suspension spring S, which is a coil spring and is arranged on the outer periphery of the shock absorber main body A, is interposed between a seat portion 7c1 of a fixed spring bearing 7c fixedly provided on the piston rod 2 and a seat portion 10a of a movable spring bearing 10 attached to the outer periphery of the cylinder 1. By being interposed between the fixed spring bearing 7c and the movable spring bearing 10, the suspension spring S is constantly biased in an extension direction that separates the piston rod 2 and the cylinder 1 in the shock absorber main body A in the axial direction, and when the shock absorber D with vehicle height adjustment function is interposed between the body and rear wheel of a saddle-ride type vehicle, it elastically supports the vehicle body.

[0040] The suction passage 20 is provided in the cap 6, opens from a recess 6a1 of the cap 6, and communicates with the liquid chamber L of the tank T, thereby connecting the pump chamber P and the tank T. A check valve 20a that only allows liquid to flow from the liquid chamber L to the pump chamber P is provided midway in the suction passage 20, and the suction passage 20 is configured as a one-way passage that only allows liquid to flow from the liquid chamber L to the pump chamber P.

[0041] The discharge passage 21 is provided in the cap 6, opens from a recess 6a1 of the cap 6, and connects to the switching valve V. The supply / discharge passage 22 penetrates the bottom 8a of the housing 8 and leads into the cap 6, connecting the jack chamber C of the jack J to the switching valve V. The return passage 23 is provided in the cap 6 and connects the liquid chamber L of the tank T to the switching valve V. The cap 6 also has a relief passage 35 that connects the jack chamber C of the jack J to the liquid chamber L of the tank T. The relief passage 35 is provided with a relief valve 36 that opens when the pressure in the jack chamber C reaches or exceeds a valve opening pressure, connecting the jack chamber C and the liquid chamber L and discharging the liquid in the jack chamber C to the liquid chamber L.

[0042] The switching valve V is provided in the valve housing 6c of the cap 6. The switching valve V includes a port p connected to the discharge passage 21, a port a connected to the supply / discharge passage 22, a port b connected to the return passage 23, a valve element 30 for switching the connection states of these ports p, a, and b, a spring 31 for biasing the valve element 30, and a solenoid 32 as an actuator for switching the valve element 30.

[0043] The valve body 30 has a supply position 30a that connects port p and port a to allow only the flow of liquid from the discharge passage 21 to the supply / discharge passage 22 and closes port b to block the return passage 23, an unload position 30b that connects port p and port b to connect the discharge passage 21 to the return passage 23 and closes port a to block the supply / discharge passage 22, and a discharge position 30c that connects all of ports p, a, and b to connect the discharge passage 21, the supply / discharge passage 22, and the return passage 23 to one another.

[0044] The valve body 30 is biased by a spring 31, and takes a supply position 30a when the solenoid 32 is not energized, an unload position 30b when the solenoid 32 is energized but the amount of current supplied is half the maximum current, and a discharge position 30c when the solenoid 32 is energized and the amount of current supplied is the maximum current.

[0045] Therefore, the switching valve V takes one of the supply position 30a, unload position 30b, and exhaust position 30c depending on the state of current flow to the solenoid 32: a de-energized state, a current flowing in which half the maximum current is supplied, and a state in which the maximum current is supplied. Note that the maximum current refers to the maximum amount of current that can be supplied based on the specifications of the solenoid 32. However, the amount of current when the switching valve V takes the unload position 30b and the exhaust position 30c can be set arbitrarily as long as the switching valve V can take these positions. Furthermore, the state of current flow to the solenoid 32 when the switching valve V takes the supply position 30a, the unload position 30b, and the exhaust position 30c can also be changed arbitrarily. Note that, although the actuator in this embodiment is the solenoid 32, an actuator other than a solenoid may be used as long as it is capable of applying thrust to the valve element 30 to switch the position of the valve element 30.

[0046] The height-adjustable shock absorber D is configured as described above, and the operation of the height-adjustable shock absorber D will be described below. As described above, the shock absorber main body A in the height-adjustable shock absorber D generates a damping force that impedes its own expansion and contraction as it expands and contracts. As the shock absorber main body A expands and contracts, the piston rod 2 and the pump rod 4 move relative to each other in the axial direction, expanding and contracting the volume of the pump chamber P.

[0047] When the solenoid 32 is not energized and the switching valve V is in the supply position 30a, the pump chamber P is connected to the jack chamber C and the return passage 23 is blocked. When the shock absorber body A performs an extension operation in this state, the volume of the pump chamber P is expanded, and liquid is sucked into the pump chamber P from the liquid chamber L of the tank T through the suction passage 20. Next, when the shock absorber body A performs a contraction operation, the volume of the pump chamber P is reduced, and liquid is supplied from the contracted pump chamber P to the jack chamber C through the discharge passage 21 and the supply / discharge passage 22. The switching valve V in the supply position 30a only allows liquid to flow from the pump chamber P to the jack chamber C but does not allow liquid to flow in the reverse direction. Therefore, each time the shock absorber body A repeatedly expands and contracts, the volume of the pump chamber P expands and contracts, and liquid from the liquid chamber L is sucked into the pump chamber P, and the liquid sucked into the pump chamber P is then discharged toward the jack chamber C. Therefore, when the shock absorber main body A performs an expansion / contraction operation with the switching valve V in the supply position 30a, liquid is supplied from the liquid chamber L to the jack chamber C, causing the jack chamber C to expand and pushing the movable spring bearing 10 upward in Figure 1 together with the plunger 9, thereby pushing up the body of the saddle-type vehicle and increasing the vehicle height.

[0048] When the shock absorber body A repeatedly expands and contracts with the switching valve V in the supply position 30a, the vehicle height gradually rises and the pressure in the jack chamber C also rises. When the pressure in the jack chamber C reaches the valve opening pressure of the relief valve 36, the relief valve 36 opens, connecting the jack chamber C to the fluid chamber L and releasing the liquid in the jack chamber C into the fluid chamber L. Therefore, even if the switching valve V continues to be in the supply position 30a, the vehicle height does not rise indefinitely but is maintained at the upper limit set by the valve opening pressure of the relief valve 36. In this way, when the switching valve V is in the supply position 30a, the vehicle height gradually rises as the shock absorber body A expands and contracts, and when the upper limit of the vehicle height is reached, the vehicle height does not rise any further and is maintained at a constant vehicle height. Furthermore, even if the switching valve V remains in the supply position 30a, the pressure in the pump chamber P does not exceed the pressure in the jack chamber C, so it does not rise above the valve opening pressure of the relief valve 36.

[0049] Furthermore, when half the maximum current is supplied to the solenoid 32 and the switching valve V is in the unloading position 30b, the pump chamber P is connected to the liquid chamber L of the tank T and the supply / discharge passage 22 is blocked. When the shock absorber main body A performs an extension operation in this state, the volume of the pump chamber P is expanded, so that liquid is sucked into the pump chamber P from the liquid chamber L of the tank T through the suction passage 20, but when the shock absorber main body A subsequently performs a contraction operation, the liquid is returned from the contracted pump chamber P to the liquid chamber L of the tank T through the discharge passage 21 and the return passage 23. Therefore, when the switching valve V is in the unloading position 30b, liquid is not supplied from the pump chamber P to the jack chamber C, and because the supply / discharge passage 22 is blocked, liquid is not discharged from the high-pressure jack chamber C to the tank T through the supply / discharge passage 22, so the vehicle height remains constant and does not change from the vehicle height immediately before the switching valve V was set to the unloading position 30b. Furthermore, when the switching valve V is set to the unload position 30b, the communication between the pump chamber P and the jack chamber C is cut off and the pump chamber P is connected to the liquid chamber L, so that the pressure in the pump chamber P becomes almost the same as the pressure in the liquid chamber L of the tank T. This prevents the compression side damping force generated by the shock absorber main body A due to the pressure in the pump chamber P from becoming excessive, thereby improving the ride comfort of the saddle-type vehicle.

[0050] Furthermore, when the maximum current is supplied to the solenoid 32 and the switching valve V is in the discharge position 30c, the discharge passage 21, the supply / discharge passage 22, and the return passage 23 are interconnected, thereby interconnecting the pump chamber P, the jack chamber C, and the fluid chamber L of the tank T. In this state, the pressure in the jack chamber C becomes the tank pressure, and the pump chamber P is also connected to the fluid chamber L, so no fluid is supplied to the jack chamber C. Therefore, the pressure in the jack chamber C is insufficient to support the vehicle weight, so the plunger 9 descends within the housing 8 under the influence of the vehicle weight, causing the jack J to retract and lower the vehicle height. If the switching valve V continues to be in the discharge position 30c, the jack J continues to retract due to the vehicle weight, and the plunger 9 descends until it abuts against the bottom 8a of the housing 8, thereby fully retracting the jack J and lowering the vehicle height. Furthermore, when the switching valve V is in the discharge position 30c, the pump chamber P is connected to the liquid chamber L, so the pressure in the pump chamber P becomes almost the same as the pressure in the liquid chamber L of the tank T, and the compression side damping force generated by the shock absorber main body A due to the pressure in the pump chamber P does not become excessive.

[0051] Furthermore, if resistance is applied to the flow of liquid from the supply / discharge passage 22 to the return passage 23 when the switching valve V is in the discharge position 30c, the lowering of the vehicle height will be slowed down, the impact when the plunger 9 hits the bottom 8a of the housing 8 will be alleviated, and the occupant of the saddle-type vehicle will not feel uneasy when the vehicle height is lowered.

[0052] In this way, in the shock absorber D with vehicle height adjustment function, by switching the position of the switching valve V, one of the following modes can be selected: a mode in which the vehicle height is raised, a mode in which the pressure in the pump chamber P is used as the tank pressure while maintaining the vehicle height, and a mode in which the vehicle height is lowered.

[0053] When the switching of the switching valve V is performed by the rider of the saddle-ride type vehicle, the switching valve V is set to the supply position 30a to raise the vehicle height to a desired height, and then the switching valve V is switched to the unload position 30b to maintain a constant vehicle height while generating an optimum damping force for suppressing vibration of the vehicle body in the shock absorber main body A. Furthermore, when it is desired to lower the vehicle height, such as when the saddle-ride type vehicle is stopped, the switching valve V can be switched to the discharge position 30c.

[0054] If the straddle-type vehicle is equipped with a sensor capable of detecting the vehicle height, the switching of the switching valve V may be controlled by a controller. In this case, the controller obtains information about the vehicle height detected by the sensor and switches the switching valve V to the supply position 30a to raise the vehicle height if the vehicle height is lower than a predetermined set height. If the vehicle height is higher than the set height, the controller switches the switching valve V to the discharge position 30c to lower the vehicle height. When the vehicle height reaches the set height, the controller switches the switching valve V to the unload position 30b. In addition, if the controller obtains information about the vehicle speed from the straddle-type vehicle, the controller may, for example, switch the switching valve V to the discharge position 30c to lower the vehicle height if the vehicle speed is 15 km / h or less, and switch the switching valve V so that the vehicle height reaches the set height if the vehicle speed is 20 km / h or more. In this case, the vehicle height lowering reference speed can be set arbitrarily. In this way, the controller automatically adjusts the vehicle height to suit both when the vehicle is moving and when it is stopped.

[0055] As described above, the shock absorber D with vehicle height adjustment function of this embodiment includes the cylinder 1, the piston rod 2 inserted into the cylinder 1 so as to be movable in the axial direction, the shock absorber body A having the piston 3 connected to the piston rod 2 and inserted into the cylinder 1 so as to be movable in the axial direction and dividing the inside of the cylinder 1 into an extension-side chamber R1 and a compression-side chamber R2, the pump chamber P expanding and contracting as the shock absorber body A expands and contracts, the tank T for storing liquid, the suspension spring S interposed between the movable spring bearing 10 arranged on the outer periphery of the cylinder 1 so as to be movable in the axial direction and the fixed spring bearing 7c attached to the piston rod 2, and the jack chamber C having the movable spring bearing 10 and the fixed spring bearing 7c which are mounted on the piston rod 2. the supply and discharge passage 22 connected to the jack chamber C; a return passage 23 connected to the tank T; a switching valve V having a supply position 30a that allows only the flow of liquid from the discharge passage 21 to the supply and discharge passage 22 and blocks the return passage 23; an unload position 30b that connects the discharge passage 21 to the return passage 23 and blocks the supply and discharge passage 22; and a discharge position 30c that connects the discharge passage 21 to the return passage 23.

[0056] With the shock absorber D with vehicle height adjustment function configured in this manner, when the switching valve V is set to the supply position 30a, liquid is supplied from the pump chamber P to the jack chamber C to raise the vehicle height, and when the switching valve V is set to the unload position 30b, the communication between the pump chamber P and the jack chamber C is cut off, maintaining the vehicle height while connecting the pump chamber P to the tank T, so that even if the shock absorber main body A expands or contracts, there is no increase in pressure within the pump chamber P, and further, when the switching valve V is set to the discharge position 30c, the pump chamber P, jack chamber C, and tank T are connected to each other, making it possible to lower the vehicle height.

[0057] Therefore, according to the shock absorber D with vehicle height adjustment function of this embodiment, the vehicle height can be increased or decreased by switching the switching valve V, and when maintaining a constant vehicle height, the switching valve V is set to the unload position 30b, so that the pressure in the pump chamber P becomes the tank pressure and the compression-side damping force generated by the shock absorber main body A does not become excessive. As described above, according to the shock absorber D with vehicle height adjustment function of this embodiment, the vehicle height can be adjusted in conjunction with the extension / contraction operation, and the ride comfort of the vehicle can be improved.

[0058] Furthermore, the shock absorber D with vehicle height adjustment function of this embodiment is equipped with a relief passage 35 that connects the jack chamber C and the tank T, and a relief valve 36 that is provided in the relief passage 35 and that opens the relief passage 35 when the pressure in the jack chamber C reaches the valve opening pressure, thereby allowing the flow of liquid from the jack chamber C to the tank T. With the shock absorber D with vehicle height adjustment function configured in this manner, even if the switching valve V continues to take the supply position 30a, the vehicle height will not rise endlessly but can be maintained at the upper limit of the vehicle height set by the valve opening pressure of the relief valve 36, and it is also possible to prevent the pressure in the jack chamber C from becoming abnormally high, thereby protecting the jack J.

[0059] The principle of the switching valve V has been explained above, but a specific structure of the switching valve V will be explained below. As shown in Fig. 2, the switching valve V specifically includes a first valve 50 that is installed between the discharge passage 21 and the supply / discharge passage 22 and allows liquid to flow only from the discharge passage 21 to the supply / discharge passage 22, a second valve 60 that is capable of switching between connecting and disconnecting the discharge passage 21 and the return passage 23 and is arranged in series with the first valve 50 and is biased to a position that disconnects the discharge passage 21 and the return passage 23, and a solenoid 32 that is arranged on the opposite side of the second valve 60 to the first valve. The first valve 50 and the second valve 60 are housed in a valve housing 6c provided in the cap 6.

[0060] The valve housing 6c has a solenoid mounting hole 6c1 in which the solenoid 32 is mounted, and a valve hole 6c2 that is concentric with the solenoid mounting hole 6c1 and accommodates the first valve 50 and the second valve 60. The inner diameter of the solenoid mounting hole 6c1 is larger than the inner diameter of the valve hole 6c2, and a step 6c3 is formed at the boundary between the solenoid mounting hole 6c1 and the valve hole 6c2. A threaded portion 6c4 is formed on the inner periphery of the solenoid mounting hole 6c1, and a threaded portion 6c5 is also formed on the inner periphery of the valve hole 6c2 near the opening side.

[0061] The valve hole 6c2 has an inner diameter on the back side that is smaller than the inner diameter on the opening side, and is provided with a small-diameter portion 6c21 and a large-diameter portion 6c22. One end of the discharge passage 21 opens to the back side of the large-diameter portion 6c22 of the valve hole 6c2, and the other end communicates with the pump chamber P. One end of the supply / discharge passage 22 opens to the back side of the small-diameter portion 6c21 of the valve hole 6c2, and the other end communicates with the jack chamber C. The return passage 23 has one end that opens to the step portion 6c3, and the other end communicates with the liquid chamber L of the tank T.

[0062] The first valve 50 includes a first valve seat 51b installed between the discharge passage 21 and the supply / discharge passage 22, a first valve body 52 arranged on the supply / discharge passage side of the first valve seat 51b and capable of being seated on and removed from the first valve seat 51b, and a first spring 53 that biases the first valve body 52 in the direction of seating it on the first valve seat 51b.

[0063] The first valve seat 51b is provided on a cylindrical sleeve 51 that is inserted into the valve hole 6c2. The sleeve 51 is cylindrical and includes an annular protrusion 51a that protrudes radially inward from the center of the inner circumference, a first valve seat 51b formed at the left end of the annular protrusion 51a in Fig. 2, a first port 51c that is provided near the left end in Fig. 2 and penetrates the material in the radial direction to communicate between the inside and the outside, and a second port 51d that opens from the inner circumference of the annular protrusion 51a, extends radially, and communicates with the outside.

[0064] 2 , the sleeve 51 is inserted into the valve hole 6c2, with the annular spring seat 54 fitted to the left end thereof, and the outer periphery of the sleeve 51 is fitted to the inner periphery of the small diameter portion 6c21 of the valve hole 6c2. Then, a seal ring 55 housed in an annular groove 51e on the outer periphery of the sleeve 51 tightly fits between the opening of the discharge passage 21 and the opening of the supply / discharge passage 22 on the inner periphery of the small diameter portion 6c21, preventing communication between the discharge passage 21 and the supply / discharge passage 22 through the outer periphery of the sleeve 51. When the sleeve 51 is housed in the valve hole 6c2, the first port 51c faces the opening of the supply / discharge passage 22, and the second port 51d faces the opening of the discharge passage 21, thereby communicating the discharge passage 21 and the supply / discharge passage 22 through the interior thereof.

[0065] The spring seat 54 is annular and has a flange 54a provided on the outer periphery at the left end in Figure 2, and an annular guide 54b protruding in the axial direction from the outer periphery at the left end in Figure 2, and is fitted onto the inner periphery at the left end of the sleeve 51 in Figure 2, so that the flange 54a abuts against the left end of the sleeve 51.

[0066] The first valve body 52 is inserted into the sleeve 51 on the left side of the annular protrusion 51a in Fig. 2 so as to be axially movable. More specifically, the first valve body 52 includes a cylindrical body portion 52a that is in sliding contact with the inner periphery of the sleeve 51, a valve head 52b that is provided at the right end of the body portion 52a in Fig. 2 and has a conical surface that faces the first valve seat 51b in the axial direction, a spring fitting portion 52c that protrudes from the left end of the body portion 52a in Fig. 2 and has an outer diameter smaller than that of the body portion 52a, and a rod portion 52d that extends leftward from the left end of the spring fitting portion 52c in Fig. 2 and has an outer diameter smaller than that of the spring fitting portion 52c.

[0067] The first valve element 52 can move in the axial direction within the sleeve 51, and when the valve head 52b is seated on the first valve seat 51b, it cuts off communication between the discharge passage 21 and the supply / discharge passage 22, and when it moves leftward in Figure 2 within the sleeve 51 and moves the valve head 52b away from the first valve seat 51b, it connects the discharge passage 21 and the supply / discharge passage 22. The first valve element 52 has a groove 52e formed on the outer periphery of the body 52a along the axial direction, over the entire length of the body 52a, and when inserted into the sleeve 51, it does not close the inner periphery of the sleeve 51, and when the valve is open, it connects the discharge passage 21 and the supply / discharge passage 22 through the groove 52e.

[0068] The first spring 53 has one end fitted around the outer periphery of the spring fitting portion 52c of the first valve body 52 and abutting against the left end of the body portion 52a in Figure 2, and the other end inserted into the guide 54b of the spring seat 54 and abutting against the end of the spring seat 54, and is interposed in a compressed state between the first valve body 52 and the spring seat 54. Therefore, the first spring 53 always urges the first valve body 52 toward the first valve seat 51b to seat it on the first valve seat 51b.

[0069] In the first valve 50 configured as described above, when the pressure in the discharge passage 21 becomes higher than the pressure in the supply / discharge passage 22, the first spring 53 compresses and the first valve element 52 retreats to the left in FIG. 2 within the sleeve 51 to open, thereby communicating the discharge passage 21 with the supply / discharge passage 22. On the other hand, when the pressure in the supply / discharge passage 22 becomes higher than the pressure in the discharge passage 21, the first spring 53 and the pressure in the supply / discharge passage 22 press the first valve element 52 against the first valve seat 51 b to close, thereby blocking the discharge passage 21 from the supply / discharge passage 22. Furthermore, when the first spring 53 is compressed by the thrust of the solenoid 32 via the second valve 60, the first valve element 52 retreats to the left in FIG. 2 within the sleeve 51 to open, thereby communicating the discharge passage 21 with the supply / discharge passage 22.

[0070] The second valve 60 includes a second valve seat 61d installed between the discharge passage 21 and the return passage 23, a second valve body 62 arranged on the discharge passage side of the second valve seat 61d and capable of being seated on and removed from the second valve seat 61d, and a second spring 63 that biases the second valve body 62 in the direction of seating it on the second valve seat 61d.

[0071] The second valve seat 61d is provided on a cylindrical valve seat member 61 that fits onto the outer periphery of the sleeve 51 at the right end in Figure 2. The valve seat member 61 includes a large-diameter cylindrical portion 61a that fits onto the outer periphery of the sleeve 51, an annular flange portion 61b that protrudes radially inward from the inner periphery of the large-diameter cylindrical portion 61a, and a small-diameter cylindrical portion 61c that protrudes from the inner periphery of the flange portion 61b toward the opposite side from the sleeve, and the second valve seat 61d is formed on the inner periphery of the flange portion 61b at the left end in Figure 2. The valve seat member 61 also includes a port 61e that radially penetrates the small-diameter cylindrical portion 61c. The valve seat member 61 configured as described above has a threaded portion 61f on the outer periphery of the large-diameter cylindrical portion 61a that is threadedly coupled to a threaded portion 6c5 provided in the valve hole 6c2. When threadedly coupled to the valve hole 6c2, the sleeve 51 and spring seat 54 are pressed against the bottom of the valve hole 6c2, securing them within the valve hole 6c2. Furthermore, a seal ring 64 housed in an annular groove 61g provided on the outer periphery of the large-diameter cylindrical portion 61a closely contacts the inner periphery of the large-diameter portion 6c22 of the valve hole 6c2. A port 61e provided in the small-diameter cylindrical portion 61c of the valve seat member 61 communicates with the return passage 23 that opens to the stepped portion 6c3 of the valve housing 6c. The interior of the small-diameter cylindrical portion 61c is connected to the first port 51c and the second port 51d through the sleeve 51. Therefore, the return passage 23 is connected to the discharge passage 21 and the supply / discharge passage 22 through the sleeve 51 and the valve seat member 61. Since the seal ring 64 is in close contact with the inner periphery of the large diameter portion 6c22 of the valve hole 6c2, communication between the discharge passage 21 and the return passage 23 through the outer periphery of the valve seat member 61 is prevented.

[0072] The second valve body 62 is inserted into the sleeve 51 on the right side of the annular protrusion 51 a in Fig. 2 so as to be axially movable. More specifically, the second valve body 62 includes a cylindrical body portion 62 a that slides against the inner periphery of the sleeve 51, a valve head 62 b that is provided at the right end of the body portion 62 a in Fig. 2 and has a conical surface that faces the second valve seat 61 d in the axial direction, a spring fitting portion 62 c that protrudes from the left end of the body portion 62 a in Fig. 2 and has an outer diameter smaller than that of the body portion 62 a, and a rod portion 62 d that extends leftward from the left end of the spring fitting portion 62 c in Fig. 2 and has an outer diameter smaller than that of the spring fitting portion 52 c and the inner diameter of the annular protrusion 51 a of the sleeve 51.

[0073] The second valve body 62 can move in the axial direction within the sleeve 51, and when the valve head 62b is seated on the second valve seat 61d, it cuts off communication between the discharge passage 21 and the return passage 23, and when it moves leftward in Figure 2 within the sleeve 51 and moves the valve head 62b away from the second valve seat 61d, it connects the discharge passage 21 and the return passage 23. The second valve body 62 has a groove 62e formed on the outer periphery of the body portion 62a along the axial direction over the entire length of the body portion 62a, and when inserted into the sleeve 51, it does not close the inner periphery of the sleeve 51, and when the valve is open, it connects the discharge passage 21 and the return passage 23 through the groove 62e.

[0074] 2, when the second valve body 62 seats the valve head 62b on the second valve seat 61d, the left end of the rod portion 62d in FIG. 2 separates from the first valve body 52, and when the second valve body 62 moves leftward within the sleeve 51, the rod portion 62d comes into contact with the tip of the valve head 52b of the first valve body 52. ​​Then, when the second valve body 62 moves further leftward in FIG. 2 within the sleeve 51 after the rod portion 62d has come into contact with the first valve body 52, it can push the first valve body 52 leftward. The first valve body 52, pushed by the second valve body 62 in this manner, moves the valve head 52b leftward within the sleeve 51 from the position where it seats on the first valve seat 51b, and separates the valve head 52b from the first valve seat 51b. In a specific switching valve V, the first valve body 52 and the second valve body 62 have the same shape and are the same parts, so when assembling the switching valve V, there is no need to assemble the first valve body 52 and the second valve body 62 separately, which prevents incorrect assembly.

[0075] The second spring 63 is interposed in a compressed state between the second valve body 62 and the annular protrusion 51 a, with one end fitted around the outer periphery of the spring fitting portion 62 c of the second valve body 62 and abutting against the left end of the body portion 62 a in Fig. 2 , and the other end abutting against the right end of the annular protrusion 51 a of the sleeve 51 in Fig. 2. Therefore, the second spring 63 constantly biases the second valve body 62 toward the second valve seat 61 d to seat it on the second valve seat 61 d.

[0076] The solenoid 32 as an actuator includes a frame 32a screwed to the inner periphery of the solenoid mounting hole 6c1 of the valve housing 6c, a push rod 32b inserted into the frame 32a so as to be movable in the axial direction, a cylindrical first stationary core and a cylindrical second stationary core (not shown) inserted into the frame 32a and spaced apart in the axial direction, a movable core (not shown) housed in the frame 32a between the first and second stationary cores so as to be movable in the axial direction and connected to the push rod 32b, and a coil attached to the outer periphery of the first and second stationary cores and housed in the frame 32a. A threaded portion 32a1 screwed to a threaded portion 6c4 formed on the inner periphery of the solenoid mounting hole 6c1 is provided on the outer periphery of the left end of the frame 32a in Figure 2, and the solenoid 32 is mounted to the valve housing 6c by inserting the left side of the frame 32a in Figure 2 into the solenoid mounting hole 6c1. In addition, even in a specific switching valve V, the actuator may be a direct acting actuator other than the solenoid 32.

[0077] The outer diameter of the left end of the push rod 32b in Figure 2 is smaller than the inner diameter of the flange portion 61b of the valve seat member 61, and the push rod 32b is inserted into the flange portion 61b and abuts against the second valve body 62. When not energized, that is, when no current is supplied, the solenoid 32 does not generate thrust and does not press the second valve body 62 of the second valve 60. On the other hand, when current is supplied, the solenoid 32 generates thrust through the push rod 32b to press the second valve body 62 leftward in Figure 2.

[0078] The specific configuration of the switching valve V is as described above. Next, the operation of the switching valve V will be described. When the solenoid 32 is not energized, it does not generate thrust to push the push rod 32b and does not press the second valve body 62. When the solenoid 32 is not energized in this way, the second valve body 62 is urged by the second spring 63 to seat on the second valve seat 61d, closing the second valve 60, and the second valve body 62 is separated from the first valve body 52, so that the first valve body 52 is urged by the first spring 53 to seat on the first valve seat 51b, closing the first valve 50. In this state, the discharge passage 21 and the return passage 23 are disconnected by the closing of the second valve 60, so that when the pump chamber P expands or contracts, the pressure in the pump chamber P becomes high, and when the pressure in the pump chamber P exceeds the pressure in the jack chamber C, the first valve body 52, which receives the pressure of the pump chamber P through the discharge passage 21, moves away from the first valve seat 51b, opening the first valve 50. As described above, when the solenoid 32 is not energized, the specific switching valve V takes the supply position to allow the flow of liquid from the discharge passage 21 toward the supply / discharge passage 22, and to disconnect the discharge passage 21 from the return passage 23.

[0079] Next, the operation of the switching valve V when half the maximum current is supplied to the solenoid 32 will be described. In this energized state where half the maximum current is supplied to the solenoid 32, the force of the solenoid 32 pushing the second valve body 62 via the push rod 32b overcomes the spring force of the second spring 63, causing the second valve body 62 to move leftward. However, the second valve body 62 does not abut against the first valve body 52, or even if it does abut, it does not displace the first valve body 52. ​​Therefore, in this state, the second valve 60 is in an open state, connecting the discharge passage 21 and the return passage 23, while the first valve 50 is closed. In this state, the discharge passage 21 and the return passage 23 are connected by the opening of the second valve 60. Therefore, even if the pump chamber P is connected to the liquid chamber L and expands or contracts, the pressure in the pump chamber P does not increase, and the second valve 60 does not open due to the pressure of the pump chamber P. As described above, when the solenoid 32 is energized to supply half the maximum current, the specific switching valve V takes the unload position, connecting the discharge passage 21 to the return passage 23 but cutting off the connection between the discharge passage 21 and the supply / discharge passage 22.

[0080] Next, the operation of the switching valve V when the maximum current is supplied to the solenoid 32 will be described. When the maximum current is supplied to the solenoid 32, the solenoid 32 exerts a large force to push the second valve body 62 via the push rod 32b, increasing the amount of movement of the second valve body 62 to the left in FIG. 2 . The second valve body 62 abuts against the first valve body 52, and both the second valve body 62 and the first valve body 52 move leftward, opening both the first valve 50 and the second valve 60. Therefore, in this state, the discharge passage 21, the supply / discharge passage 22, and the return passage 23 are interconnected. As described above, when the maximum current is supplied to the solenoid 32, the specific switching valve V assumes the exhaust position, interconnecting the discharge passage 21, the supply / discharge passage 22, and the return passage 23.

[0081] In this way, depending on the current supply status of the solenoid 32, the specific switching valve V takes one of the following positions: a supply position in which liquid is supplied from the pump chamber P to the jack chamber C to extend the jack J and raise the vehicle height; an unload position in which the pump chamber P is connected to the liquid chamber L while maintaining a constant vehicle height, thereby preventing the compression damping force of the shock absorber D with vehicle height adjustment function from becoming excessive; and a discharge position in which the jack chamber C is connected to the liquid chamber L to contract the jack J and lower the vehicle height.

[0082] As described above, the specific switching valve V of this embodiment comprises a first valve 50 that is installed between the discharge passage 21 and the supply / discharge passage 22 and that allows only the flow of liquid from the discharge passage 21 to the supply / discharge passage 22, a second valve 60 that is capable of switching between connecting and blocking the communication between the discharge passage 21 and the return passage 23, that is arranged in series with the first valve 50, and that is biased to a position that blocks the communication between the discharge passage 21 and the return passage 23, and a solenoid 32 that is arranged on the opposite side of the second valve 60 to the first valve.

[0083] The shock absorber D with vehicle height adjustment function configured in this manner has the first valve 50 and the second valve 60 arranged in series, and by using one solenoid 32, thrust is applied to the first valve 50 and the second valve 60 to open and close the first valve 50 and the second valve 60, so the switching valve V becomes lightweight and compact, improving the mountability of the shock absorber D with vehicle height adjustment function on a saddle-ride type vehicle and reducing manufacturing costs, making it inexpensive.

[0084] Furthermore, in a specific switching valve V of this embodiment, the first valve 50 has a first valve seat 51b installed between the discharge passage 21 and the supply / discharge passage 22, a first valve element 52 arranged on the supply / discharge passage side of the first valve seat 51b and capable of being seated on and separated from the first valve seat 51b, and a first spring 53 that biases the first valve element 52 in a direction to seat it on the first valve seat 51b. The second valve 60 has a second valve seat 61d installed between the discharge passage 21 and the return passage 23, a second valve element 62 arranged on the discharge passage side of the second valve seat 61d and capable of being seated on and separated from the second valve seat 61d, and a first spring 53 that biases the second valve element 62 in a direction to seat it on the second valve seat 61d. and a second spring 63 that biases the valve body 52 in a direction that causes the valve body 52 to open. When the first valve body 52 is seated on the first valve seat 51 b and the second valve body 62 is seated on the second valve seat 61 d, the first valve body 52 and the second valve body 62 are spaced apart, and the valve body 52 is switched between a supply position where the solenoid 32 does not apply thrust to the first valve body 52 or the second valve body 62, a position where the solenoid 32 applies thrust only to the second valve body 62 and thereby assumes an unload position, and a position where the solenoid 32 applies thrust to the second valve body 62 and also to the first valve body 52 via the second valve body 62 and thereby assumes a discharge position.

[0085] The shock absorber D with vehicle height adjustment function configured in this manner can easily switch between the supply position, unload position, and discharge position depending on the amount of current supplied to the solenoid 32, and the first valve 50 and the second valve 60 can each be composed of three components: a valve seat, a valve body, and a spring, thereby simplifying the structure. Furthermore, by sharing the same parts for the first valve body 52 and the second valve body 62, incorrect assembly can be prevented when assembling the switching valve V.

[0086] Although the preferred embodiment of the present invention has been described in detail, modifications, variations and changes can be made thereto without departing from the scope of the appended claims.

[0087] DESCRIPTION OF SYMBOLS 1: Cylinder, 2: Piston rod, 3: Piston, 7c: Fixed spring bearing, 10: Movable spring bearing, 20: Suction passage, 21: Discharge passage, 22: Supply / discharge passage, 23: Return passage, 30a: Supply position, 30b: Unload position, 30c: Discharge position, 35: Relief passage, 36: Relief valve, 50: First valve, 51b: First valve seat, 52: First valve body, 53: First spring, 60: Second valve, 61d: Second valve seat, 62: Second valve body, 63: Second spring, A: Shock absorber body, C: Jack chamber, D: Shock absorber with vehicle height adjustment function, J: Jack, P: Pump chamber, R1: Extension side chamber, R2: Compression side chamber, S: Suspension spring, T: Tank, V: Switching valve

Claims

1. A shock absorber with a vehicle height adjustment function, comprising: a shock absorber body including a cylinder, a piston rod inserted into the cylinder so as to be axially movable, and a piston connected to the piston rod, inserted into the cylinder so as to be axially movable, and dividing the inside of the cylinder into an extension side chamber and a compression side chamber; a pump chamber which expands and contracts as the shock absorber body expands and contracts; a tank for storing liquid; a suspension spring interposed between a movable spring bearing arranged on the outer periphery of the cylinder so as to be axially movable and a fixed spring bearing attached to the piston rod; a jack having a jack chamber and capable of displacing the movable spring bearing relative to the cylinder by liquid supplied and discharged into the jack chamber; a suction passage which only allows the flow of liquid from the tank to the pump chamber; a discharge passage connected to the pump chamber; a supply and discharge passage connected to the jack chamber; and a return passage connected to the tank. a switch valve having a supply position that allows only the flow of liquid from the discharge passage to the supply and discharge passage and blocks the return passage, an unload position that connects the discharge passage and the return passage and blocks the supply and discharge passage, and a discharge position that connects the discharge passage, the supply and discharge passage, and the return passage to each other.

2. A shock absorber with vehicle height adjustment function as described in claim 1, comprising: a relief passage that connects the jack chamber and the tank; and a relief valve that is provided in the relief passage and opens the relief passage when the pressure in the jack chamber reaches a valve opening pressure, thereby allowing liquid to flow from the jack chamber to the tank.

3. A shock absorber with vehicle height adjustment function as claimed in claim 1, wherein the switching valve comprises: a first valve installed between the discharge passage and the supply and discharge passage and allowing only the flow of liquid from the discharge passage to the supply and discharge passage; a second valve capable of switching between communication and blocking between the discharge passage and the return passage, which is arranged in series with the first valve and is biased to a position where it blocks the discharge passage and the return passage; and an actuator arranged on the opposite side of the second valve to the first valve.

4. A shock absorber with vehicle height adjustment function as claimed in claim 3, wherein the first valve has: a first valve seat installed between the discharge passage and the supply and discharge passage; a first valve body arranged on the supply and discharge passage side of the first valve seat and capable of seating on and releasable from the first valve seat; and a first spring which urges the first valve body in a direction to seat it on the first valve seat; the second valve has: a second valve seat installed between the discharge passage and the return passage; a second valve body arranged on the discharge passage side of the second valve seat and capable of seating on and releasable from the second valve seat; and a second spring which urges the second valve body in a direction to seat it on the second valve seat; and when the first valve body is seated on the first valve seat and the second valve body is seated on the second valve seat, the first valve body and the second valve body are separated from each other; and the switching valve is a state in which the actuator applies thrust only to the second valve body and assumes the unloading position; and a state in which the actuator applies thrust to the second valve body and also to the first valve body via the second valve body and assumes the discharge position.

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