Shock absorber with vehicle height adjustment function

Abstract

To provide a shock absorber with a vehicle height adjustment function which enables vehicle height adjustment to be performed in conjunction with expansion / contraction operation and can achieve improvement of the riding quality in a vehicle.SOLUTION: A shock absorber D with a vehicle height adjustment function includes: a shock absorber body A; a pump chamber P which expands or contracts in conjunction with expansion and contraction of the shock absorber body A; a tank T; a suspension spring S disposed between a movable spring receiver 10 and a fixed spring receiver 7c; a jack J; a suction passage 20 which allows communication between the tank T and the pump chamber P; a discharge passage 21 connected to the pump chamber P; a supply / exhaust passage 22 connected to a jack chamber C; a return passage 23 connected to the tank T; and a selector valve V having a supply position 30a where the selector valve V allows communication between the discharge passage 21 and the supply / exhaust passage 22 and blocks the return passage 23, an unload position 30b where the selector valve V allows communication between the discharge passage 21 and the return passage 23 and blocks the supply / exhaust passage 22, and a discharge position 30c where the selector valve V allows communication among the discharge passage 21, the supply / exhaust passage 22, and the return passage 23.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Shock absorbers with vehicle height adjustment functions are used, for example, by being interposed between the body and wheels of a saddle-type vehicle, and suppress vibrations between the body and wheels by the damping force generated when the shock absorber expands or contracts, while also adjusting the vehicle height.

[0003] Such a shock absorber with height adjustment function includes, for example, a cylinder, a piston that is movably inserted into the cylinder and divides the inside of 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 the 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 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 into the piston rod and forms a pump chamber that is connected to the jack chamber together with the piston rod.

[0004] When a shock absorber with vehicle height adjustment configured in this manner expands and contracts due to the vibrations input when the saddle-type vehicle is traveling, 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 the hydraulic oil in the cylinder and discharges it into the jack chamber, pushing the movable spring holder out of the jack chamber and raising the vehicle height (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-128427 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional shock absorbers with height adjustment function can automatically raise the vehicle height to a specified height by utilizing the expansion and contraction of the pump chamber during travel of a saddle-type vehicle, 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 height adjustment function, the damping force during contraction is high, which often causes a passenger in a saddle-type vehicle to perceive the ride as rough, and there is a demand for improved ride comfort.

[0008] SUMMARY OF THE PRESENT DISCLOSURE 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 conjunction with the expansion and contraction operation and can improve the ride comfort of the vehicle. [Means for solving the problem]

[0009] In order to solve the above problems, the shock absorber with vehicle height adjustment function of the present invention includes a shock absorber body having a cylinder, a piston rod inserted into the cylinder so as to be movable in the axial direction, and 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 expansion-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 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 is provided with a jack that can displace a movable spring bearing relative to the cylinder by liquid being pumped into the jack, a suction passage that only allows liquid to flow 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, a return passage connected to the tank, and a switching valve that has a supply position that only allows liquid to flow from the discharge passage to the supply and discharge passage and blocks the return passage, an unload position that connects the discharge passage to 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.

[0010] With this height-adjustable shock absorber configured in this manner, when the switching valve is in 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 in the unload position, the communication between the pump chamber and the jack chamber is cut off to maintain the vehicle height while the pump chamber is connected to the tank, so that no increase in pressure in the pump chamber occurs even when the shock absorber body expands or contracts, and further, when the switching valve is in the discharge position, the pump chamber, jack chamber and tank are connected to each other, making it possible to lower the vehicle height.

[0011] The shock absorber with height adjustment function may also include a relief passage that communicates the jack chamber with 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 the valve opening pressure to allow the flow of liquid from the jack chamber to the tank. With the shock absorber with height adjustment function configured in this way, the vehicle height does not rise endlessly even if the switching valve continues to take the supply position, and the vehicle height can be maintained at the upper limit set by the relief valve opening pressure, and the pressure in the jack chamber can be prevented from becoming abnormally high, thereby protecting the jack.

[0012] Furthermore, the switching valve in the height adjustable shock absorber may include a first valve that is installed between the discharge passage and the supply / discharge passage and that allows only the flow of liquid from the discharge passage to the supply / discharge passage, a second valve that is capable of switching between communication and blocking between the discharge passage and the return passage and that 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 that is provided on the opposite side of the second valve to the first valve. According to the height adjustable shock absorber configured in this manner, the first valve and the second valve are arranged in series, and a single actuator is used to apply thrust to the first valve and the second valve to open and close the first valve and the second valve, so that the switching valve becomes lightweight and compact, improving the mountability of the height adjustable shock absorber on a saddle-type vehicle and reducing manufacturing costs, making it inexpensive.

[0013] Furthermore, the first valve has a first valve seat installed between the discharge passage and the supply / discharge passage, a first valve body arranged on the supply / discharge passage side of the first valve seat and capable of seating on and releasable from the first valve seat, and a first spring that urges the first valve body in a direction to seat it on the first valve seat, and 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 that urges the second valve body in a direction to seat it on the second valve seat, In a state in which the first valve body is seated on the valve seat and the second valve body is seated on the second valve seat, the first valve body and the second valve body are spaced apart, and the switching valve may be configured to switch between a state in which the actuator does not apply thrust to the first valve body and the second valve body and takes a supply position, a state in which the actuator applies thrust only to the second valve body and takes an unloaded position, and a state in which the actuator applies thrust to the second valve body and also applies thrust to the first valve body via the second valve body and takes a discharge position.

[0014] The shock absorber with height adjustment function configured in this way can easily switch between the supply position, unload position and discharge position depending on the amount of current supplied to the actuator, and the first and second valves can each be composed of three parts: a valve seat, a valve body and a spring, simplifying the structure. Also, by sharing parts for the first valve body and the second valve body, it is possible to prevent incorrect assembly when assembling the switching valve. Effect of the Invention

[0015] According to the shock absorber with vehicle height adjustment function of the present invention, the vehicle height can be adjusted by extending and contracting, and the ride comfort of the vehicle can be improved. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of a shock absorber with height adjustment function according to one embodiment. [Diagram 2] FIG. 2 is a diagram showing a specific example of a switching valve of a shock absorber with a vehicle height adjustment function in one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the present invention will be described 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 shock absorber body A having a cylinder 1, a piston rod 2 inserted into the cylinder 1 so as to be movable in the axial direction, 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 expansion side chamber R1 and a compression side chamber R2, a pump chamber P which expands and contracts with the expansion and contraction of the shock absorber body A, 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 movable by liquid supplied and discharged into the jack chamber C. The 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 to 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, and a switching valve V having a supply position 30a that allows only the flow of liquid from the discharge passage 21 to the supply / 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 / 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 each other.

[0018] Although not shown, this shock absorber D with height adjustment function is used by being interposed between the body and the rear wheel of a saddle-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 be used in vehicles other than saddle-type vehicles.

[0019] Hereinafter, each part of the shock absorber D with vehicle height adjustment function will be described in detail. First, each part of the shock absorber main body A will be described. As shown in Fig. 1, the cylinder 1 is cylindrical, and the upper end in Fig. 1 is closed by a rod guide 5, and the lower end in Fig. 1 is closed by a cap 6.

[0020] 1 is annular and has an annular seal ring 5a on its outer periphery which closely contacts the inner periphery of the cylinder 1, and an annular seal ring 5b and annular bush 5c on its inner periphery which slide against the outer periphery of the piston rod 2. The rod guide 5 is restricted from moving upward in FIG. 1 with respect to the cylinder 1 by a C-ring 40 attached to the inner periphery of the upper end of the cylinder 1 in FIG.

[0021] The piston rod 2, which is movably inserted into the cylinder 1, is inserted through the seal ring 5b and bush 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 bush 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, the 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 in FIG. 1 of the cylinder 1 via the inner periphery of the rod guide 5.

[0022] The piston rod 2 is cylindrical and includes a small diameter portion 2a at its lower end in Fig. 1 whose outer diameter is smaller than that of its upper portion, and a piston 3 is attached to its outer periphery, 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 penetrates radially through 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-type vehicle is attached to the upper end of the piston rod 2 in Fig. 1.

[0023] Next, a piston 3 attached to a piston rod 2 is inserted into the cylinder 1 so as to be movable in the axial direction, 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. In this embodiment, the liquid is hydraulic oil, but it may be liquid other than hydraulic oil, such as water or an aqueous solution. The through hole 2c of the piston rod 2 opens upward in FIG. 1 from the small diameter portion 2a on which the piston 3 is attached and faces the extension-side chamber R1, so that the inside of the piston rod 2 is communicated with the extension-side chamber R1 via the through hole 2c.

[0024] The piston 3 is annular and is attached to the outer periphery of the small diameter portion 2a of the piston rod 2, and has an expansion side port 3a and a compression side port 3b that communicate in parallel with the expansion side chamber R1 and the compression side chamber R2, respectively. An expansion side damping valve 13 that is annular and is attached to the outer periphery of the small diameter portion 2a and opens and closes the expansion side port 3a is stacked at the lower end of the piston 3 in FIG. 1. A compression side damping valve 14 that is annular and 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 expansion side damping valve 13, and the compression side damping valve 14 are fitted to 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 screwed to the lower end of the small diameter portion 2a.

[0025] In the height adjustable shock absorber D of this embodiment, the extension-side damping valve 13 is a laminated leaf valve that is configured by laminating a plurality of annular plates at the lower end of the piston 3 in FIG. 1, and is fixed at the inner circumferential side and opens the extension-side port 3a when the outer circumferential side is deflected by the pressure of the extension-side chamber R1. The extension-side damping valve 13 can open and close the extension-side port 3a, and opens the valve when the height adjustable shock absorber D is expanded to provide resistance to the flow of liquid passing through the extension-side port 3a from the extension-side chamber R1 to the compression-side chamber R2, and closes the valve when the height adjustable shock absorber D is contracted 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 provides resistance to the flow of liquid from the extension-side chamber R1 to the compression-side chamber R2 and exerts a damping force that prevents the extension of the height adjustable shock absorber D when the height adjustable shock absorber D is expanded.

[0026] On the other hand, in the shock absorber D with height adjustment function of this embodiment, the compression side damping valve 14 is a laminated leaf valve that is configured by laminating a plurality of annular plates on the upper end of the piston 3 in FIG. 1, and is fixed on the inner circumferential side, and opens the compression side port 3b when the outer circumferential side is deflected by the pressure of the compression side chamber R2. The compression side damping valve 14 can open and close the compression side port 3b, and opens the valve when the shock absorber D with height adjustment function contracts to provide resistance to the flow of liquid passing through the compression side port 3b from the compression side chamber R2 to the expansion side chamber R1, and closes the valve when the shock absorber D with height adjustment function expands to block the compression side port 3b. Note that the compression side damping valve 14 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 liquid from the compression side chamber R2 to the expansion side chamber R1 and exerts a damping force that prevents the shock absorber D with height adjustment function contracts when the shock absorber D with height adjustment function contracts. Although not shown, an orifice is provided in parallel with the extension side damping valve 13 and the compression side damping valve 14. The orifice is formed, for example, by a notch provided in an annular plate constituting the extension side damping valve 13 and the compression side damping valve 14, or by a stamp provided on the valve seat of the piston 3 on which the annular plate sits and leaves the seat.

[0027] 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. Also, when the expansion side damping valve 13 and the compression side damping valve 14 are closed, the orifice provides resistance to the flow of liquid passing through the expansion side port 3a and the compression side port 3b to travel between the expansion side chamber R1 and the compression side chamber R2, and when the expansion side damping valve 13 and the compression side damping valve 14 are open, the expansion side damping valve 13 provides resistance to the flow of liquid passing through the expansion side port 3a, and the compression side damping valve 14 provides resistance to the flow of liquid passing through the compression side port 3b.

[0028] The cap 6, which closes the lower end of the cylinder 1 in Figure 1, is equipped with a cap body 6a that is connected to 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-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 a tank T.

[0029] Tank T includes a cylindrical container 16 disposed above tank holding portion 6d in FIG. 1, a plug 17 attached to the inner periphery of the upper end of container 16 in FIG. 1 to close the opening of container 16, and a diaphragm 18 sandwiched between container 16 and plug 17 to form an air chamber G in container 16 filled with gas and a liquid chamber L in container 16 filled with liquid.

[0030] The cap 6 is provided with a discharge passage 24 and a tank passage 25 that open from an upper end of the cap body 6a facing the compression side chamber R2 and communicate with an upper end facing the liquid chamber L of the tank holding portion 6d. 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.

[0031] The shock absorber main body A is connected to the body of the saddle-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-type vehicle via a bracket 6b of the cap 6 and 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.

[0032] In the shock absorber body A configured in this manner, during an extension operation in which the piston rod 2 retreats from the cylinder 1, the liquid moves from the extension-side chamber R1, which is reduced by the piston 3 displacing with the piston rod 2, to the compression-side chamber R2, which is expanded, through the extension-side port 3a, and the extension-side damping valve 13 applies resistance to the flow of the liquid, generating an extension-side damping force that hinders the extension operation. When the piston rod 2 retreats from the cylinder 1, the suction check valve 27 opens and the liquid that becomes insufficient in the cylinder 1 is supplied from the liquid chamber L of the tank T through the tank passage 25 into the cylinder 1.

[0033] On the other hand, in the shock absorber body A, during the contraction operation in which the piston rod 2 enters the cylinder 1, the compression side damping valve 14 provides resistance to the flow of liquid when the liquid moves from the compression side chamber R2, which is contracted by the piston 3 displaced together with the piston rod 2, to the expansion side chamber R1, which is expanded, through the compression side port 3b. In addition, when the liquid that becomes excessive in the cylinder 1 due to the piston rod 2 entering the cylinder 1 moves to the liquid chamber L of the tank T through the discharge passage 24, the base valve 26 provides resistance to the flow of the liquid. Therefore, during the contraction operation of the shock absorber body A, resistance is provided to the flow of the liquid by the compression side damping valve 14 and the base valve 26, generating a compression side damping force that hinders the contraction operation of the shock absorber body A. Therefore, the shock absorber D with vehicle height adjustment function can generate a damping force in accordance with the expansion and contraction of the shock absorber body A, thereby suppressing the vibration of the vehicle body.

[0034] 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, which are held by the cap body 6a of the cap 6.

[0035] The cap body 6a has a recess 6a1 in the center of its upper end in Fig. 1, and the lower end of the cylindrical pump rod 4 in Fig. 1 is inserted into the recess 6a1. A retaining ring 28 that prevents the pump rod 4 from slipping out of the recess 6a1 is provided in the recess 6a1, and the pump rod 4 is held in the cap 6. A seal ring 29 that comes into close contact with the outer periphery of the pump rod 4 is also provided in the recess 6a1, and the gap between the cap 6 and the outer periphery of the pump rod 4 is sealed.

[0036] The pump rod 4 extends from the cap 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 bush 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 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 on the inside, and when the shock absorber body A expands and contracts, the pump rod 4 and the piston rod 2 move relative to each other in the axial direction, so that the volume of the pump chamber P expands and contracts.

[0037] 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 small amount of radial vibration is permitted at the upper end in Fig. 1, and when it is inserted into the piston rod 2, it can smoothly advance and retreat into the piston rod 2 following the piston rod 2. As described above, the pump chamber P is provided inside the shock absorber body A by the piston rod 2 which is cylindrical, and the pump rod 4 which advances and retreats into the piston rod 2 as the shock absorber body A expands and contracts, so that the pump chamber P can be installed without increasing the size of the shock absorber body A; however, the pump chamber P may be provided outside the shock absorber body A.

[0038] 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. The fixed spring bearing 7c is integral with the bracket 7, but may be attached to the piston rod 2 separately from the bracket 7.

[0039] The cushion rubber 41 faces the bump stopper 42 in the axial direction, which is attached to the upper end of the cylinder 1 in Figure 1. When the shock absorber D with height adjustment function contracts to near the stroke end, the cushion rubber 41 comes into contact with the bump stopper 42 and is compressed, thereby exerting a resilient force to cushion the impact when the shock absorber D with height adjustment function contracts to the maximum extent.

[0040] A jack J for driving a movable spring bearing 10 is provided on the outer periphery of the cylinder 1, which is on the lower side in FIG. 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, and moves 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 part 8a that fits into the outer periphery of the cylinder 1, and a cylindrical part 8b that rises upward in FIG. 1 from the outer periphery of the bottom part 8a. A seal ring 8c that is in close contact with the outer periphery of the cylinder 1 is accommodated in an annular groove (not shown) provided on the inner periphery of the bottom part 8a, and an annular dust seal 8d and a seal ring 8e are attached to the inner periphery of the opening end of the cylindrical part 8b, in that order from the atmosphere side.

[0041] Furthermore, a plunger 9 is attached to 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 in the cylindrical portion 8b together with the housing 8. The plunger 9 is cylindrical and slides against 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 inside the cylindrical portion 8b. The plunger 9 has an annular protrusion 9a that protrudes upward from the inner periphery at the upper end, and also has an annular dust seal 9b, a bush 9c, and a seal ring 9d on its inner periphery, which slide against the outer periphery of the cylinder 1, in that order from the atmosphere side.

[0042] When the plunger 9 is inserted into the cylindrical portion 8b of the housing 8, the dust seal 8d and the seal ring 8e provided on the inner circumference of the cylindrical portion 8b slide against the outer circumference of the plunger 9, and the dust seal 9b, the bush 9c, and the seal ring 9d provided on the inner circumference of the plunger 9 slide against the outer circumference of the cylinder 1, so that the jack chamber C is sealed. The plunger 9 is movable in the vertical direction in FIG. 1 relative to the cylinder 1 and the housing 8, and can move up and down within a range from a position where the lower end abuts against the bottom portion 8a to maximize compression of the jack chamber C to a position where the plunger 9 abuts against a stopper ring 70 fixed to the outer circumference of the cylinder 1 to restrict upward movement relative to the housing 8. An annular recess 9e is provided on the inner circumference of the lower end of the plunger 9, so that when the lower end of the plunger 9 abuts against the bottom portion 8a to minimize the volume of the jack chamber C, the lower end face of the plunger 9 does not come into close contact with the entire upper surface of the bottom portion 8a. In this way, sticking of the plunger 9 to the bottom portion 8a is suppressed, and smooth movement of the plunger 9 is ensured.

[0043] 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 faces the seat portion 7c1 of the fixed spring bearing 7c in the axial direction, 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 respect to the cylinder 1 by fitting to the protrusion 9a. The movable spring bearing 10 has the seat portion 10a seated on the outer periphery of the protrusion 9a at the upper end of the plunger 9, and can move in the up-down direction in FIG. 1, which is the axial direction, together with the plunger 9, relative to the cylinder 1. The movable spring bearing 10 is separate from the plunger 9, but may be provided integrally with the plunger 9.

[0044] A suspension spring S, which is a coil spring arranged on the outer periphery of the shock absorber 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 body A in the axial direction, and when the shock absorber D with vehicle height adjustment function is interposed between the body and the rear wheel of a saddle-type vehicle, it elastically supports the vehicle body.

[0045] 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 in the middle of the suction passage 20, and the suction passage 20 is set as a one-way passage that only allows liquid to flow from the liquid chamber L to the pump chamber P.

[0046] The discharge passage 21 is provided in the cap 6, opens from the recess 6a1 of the cap 6, and is connected to the switching valve V. The supply and discharge passage 22 penetrates the bottom 8a of the housing 8 and communicates with the inside of the cap 6, and connects 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 further includes 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, thereby connecting the jack chamber C and the liquid chamber L and discharging the liquid in the jack chamber C to the liquid chamber L.

[0047] The switching valve V is provided in a valve housing 6c in 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.

[0048] The valve body 30 has a supply position 30a which communicates between port p and port a to allow liquid to flow only from the discharge passage 21 to the supply and discharge passage 22 and closes port b to block the return passage 23, an unload position 30b which communicates between port p and port b to communicate between the discharge passage 21 and the return passage 23 and closes port a to block the supply and discharge passage 22, and a discharge position 30c which communicates between all of ports p, a, and b to communicate the discharge passage 21, the supply and discharge passage 22, and the return passage 23 with one another.

[0049] The valve body 30 is biased by a spring 31 and takes a supply position 30a when no current is applied to the solenoid 32, an unload position 30b when current is applied to the solenoid 32 but the amount of current supplied is half the maximum current, and a discharge position 30c when current is applied to the solenoid 32 and the amount of current supplied is the maximum current.

[0050] Therefore, the switching valve V takes one of the supply position 30a, the unload position 30b, and the exhaust position 30c depending on the state of the solenoid 32 being energized, that is, the three states of a non-energized state, an energized state in which a current of half the maximum current is supplied, and a state in which the maximum current is supplied. The maximum current refers to the maximum amount of current that can be supplied based on the specifications of the solenoid 32, but 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 the unload position 30b and the exhaust position 30c. Furthermore, the energized state of 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. In this embodiment, the actuator is the solenoid 32, but an actuator other than a solenoid may be used as long as it is possible to apply a thrust to the valve body 30 to switch the position of the valve body 30.

[0051] The shock absorber D with height adjustment function is configured as described above, and the operation of the shock absorber D with height adjustment function will be described below. As described above, the shock absorber body A in the shock absorber D with height adjustment function exerts a damping force that hinders its own expansion and contraction as it expands and contracts. As the shock absorber 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.

[0052] 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 expands 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. When the shock absorber body A contracts, the volume of the pump chamber P is reduced, so that liquid is supplied to the jack chamber C from the contracted pump chamber P through the discharge passage 21 and the supply / discharge passage 22. The switching valve V in the supply position 30a allows only the flow of liquid from the pump chamber P to the jack chamber C but does not allow the liquid to flow in the opposite direction. Therefore, every time the shock absorber body A expands and contracts, the volume of the pump chamber P expands and contracts, so that the liquid in the liquid chamber L is sucked into the pump chamber P, and the liquid sucked into the pump chamber P is 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, which expands and pushes 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.

[0053] When the shock absorber body A repeats the expansion and contraction operation 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 opening pressure of the relief valve 36, the relief valve 36 opens and communicates the jack chamber C with the liquid chamber L to release the liquid in the jack chamber C to the liquid chamber L, so that even if the switching valve V continues to take the supply position 30a, the vehicle height does not rise endlessly and is maintained at the upper limit set by the 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 due to the expansion and contraction of the shock absorber body A, and when the upper limit of the vehicle height is reached, the vehicle height does not rise any more and is maintained at a constant vehicle height. Also, even if the switching valve V is kept 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 higher than the opening pressure of the relief valve 36.

[0054] Also, when half the maximum current is supplied to the solenoid 32 and the switching valve V is in the unloaded 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 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 body A subsequently performs a contraction operation, 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 unloaded position 30b, liquid is not supplied from the pump chamber P to the jack chamber C, and since 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 is set to the unloaded position 30b. In addition, when the switching valve V is set to the unloaded 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. Therefore, 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.

[0055] 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, and the pump chamber P, the jack chamber C, and the liquid chamber L of the tank T are interconnected. In this state, the pressure in the jack chamber C becomes the tank pressure, and the pump chamber P is also connected to the liquid chamber L, so that no liquid is supplied to the jack chamber C. Therefore, the pressure in the jack chamber C cannot support the vehicle weight, so the plunger 9 descends in the housing 8 under the weight of the vehicle, and the jack J contracts, lowering the vehicle height. If the switching valve V continues to take the discharge position 30c, the jack J continues to contract due to the vehicle weight, and the plunger 9 descends until it abuts against the bottom 8a of the housing 8, and the jack J is fully contracted and the vehicle height is at its lowest. In addition, when the switching valve V is in the discharge position 30c, 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, 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.

[0056] Furthermore, if resistance is provided to the flow of liquid from the supply and 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 abuts against the bottom 8a of the housing 8 will be mitigated, and a passenger in a saddle-type vehicle will not feel uneasy when the vehicle height is lowered.

[0057] In this way, in the shock absorber D with vehicle height adjustment function, by switching the position of the switching valve V, one of 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 can be selected.

[0058] When the switching of the switching valve V is performed by the rider of the saddle riding type vehicle, the vehicle height is raised to a desired height with the switching valve V in the supply position 30a, and then the switching valve V can be switched to the unloading position 30b to keep the vehicle height constant while generating an optimal damping force for suppressing vibration of the vehicle body in the shock absorber main body A. Also, when it is desired to lower the vehicle height, such as when the saddle riding type vehicle is stopped, the switching valve V can be switched to the discharge position 30c.

[0059] In addition, when a sensor capable of detecting the vehicle height of the saddle-ride type vehicle is provided, the switching of the switching valve V may be controlled by a controller. In this case, the controller obtains information on the vehicle height detected by the sensor, and when the vehicle height is lower than a predetermined set vehicle height, the controller switches the switching valve V to the supply position 30a to raise the vehicle height, and when the vehicle height is higher than the set vehicle height, the controller switches the switching valve V to the discharge position 30c to lower the vehicle height, and when the vehicle height reaches the set vehicle height, the controller switches the switching valve V to the unload position 30b. In addition, when the controller obtains information on the traveling speed from the saddle-ride type vehicle, the controller may control the switching valve V to be switched to the discharge position 30c to lower the vehicle height when the traveling speed is 15 km / h or less, for example, and to set the vehicle height to the set vehicle height when the traveling speed is 20 km / h or more. In this case, the traveling speed that is the reference for lowering the vehicle height can be set arbitrarily. In this way, the controller automatically adjusts the vehicle height to be suitable for when the vehicle is traveling and when the vehicle is stopped.

[0060] As described above, the shock absorber D with vehicle height adjustment function of this embodiment includes a shock absorber body A having a cylinder 1, a piston rod 2 inserted into the cylinder 1 so as to be axially movable, a piston 3 connected to the piston rod 2 and inserted into the cylinder 1 so as to be axially movable, and dividing the cylinder 1 into an expansion-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 axially movable on the outer periphery of the cylinder 1 and a fixed spring bearing 7c attached to the piston rod 2, and a jack chamber C, in which the movable spring bearing 10 is moved by liquid supplied to and discharged from the jack chamber C. the supply and discharge passage 22 connected to the jack chamber C; a return passage 23 connected to the tank T; and a switching valve V having a supply position 30a which 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 which connects the discharge passage 21 to the return passage 23 and blocks the supply and discharge passage 22, and a discharge position 30c which connects the discharge passage 21 to the return passage 23 and blocks the supply and discharge passage 22.

[0061] According to 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 no increase in pressure in the pump chamber P occurs even if the shock absorber main body A expands or contracts. Furthermore, when the switching valve V is set to the discharge position 30c, the pump chamber P, the jack chamber C and the tank T are connected to each other, making it possible to lower the vehicle height.

[0062] 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 unloaded 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.

[0063] The shock absorber D with vehicle height adjustment function of this embodiment also includes a relief passage 35 that communicates between the jack chamber C and the tank T, and a relief valve 36 that is provided in the relief passage 35 and 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. According to 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 does 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 the pressure in the jack chamber C can be prevented from becoming abnormally high, thereby protecting the jack J.

[0064] The principle of the switching valve V has been explained above, but the specific structure of the switching valve V will be explained below. As shown in Fig. 2, the specific switching valve V includes a first valve 50 that is installed between the discharge passage 21 and the supply / discharge passage 22 and allows only the flow of liquid from the discharge passage 21 to the supply / discharge passage 22, a second valve 60 that can switch between communication and blocking between the discharge passage 21 and the return passage 23, is arranged in series with the first valve 50, and is biased to a position where it blocks 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.

[0065] 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 screw portion 6c4 is formed on the inner periphery of the solenoid mounting hole 6c1, and a screw portion 6c5 is also formed on the inner periphery of the valve hole 6c2 near the opening side.

[0066] 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. The discharge passage 21 has one end that opens to the back side of the large diameter portion 6c22 of the valve hole 6c2, and the other end that communicates with the pump chamber P. The supply and discharge passage 22 has one end that opens to the back side of the small diameter portion 6c21 of the valve hole 6c2, and the other end that communicates with the jack chamber C. The return passage 23 has one end that opens to the step portion 6c3, and the other end that communicates with the liquid chamber L of the tank T.

[0067] The first valve 50 includes a first valve seat 51b disposed between the discharge passage 21 and the supply / discharge passage 22, a first valve body 52 disposed on the supply / discharge passage side of the first valve seat 51b and capable of seating on and releasable from the first valve seat 51b, and a first spring 53 that biases the first valve body 52 in a direction such that it seats on the first valve seat 51b.

[0068] 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.

[0069] 2, the sleeve 51 is inserted into the valve hole 6c2 with the annular spring seat 54 fitted to the left end in Fig. 2, and the outer periphery of the sleeve 51 is fitted into 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 provided on the outer periphery of the sleeve 51 is tightly fitted between the opening of the discharge passage 21 and the opening of the supply and exhaust passage 22 on the inner periphery of the small diameter portion 6c21, preventing the discharge passage 21 and the supply and exhaust passage 22 from communicating with each other 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 and exhaust passage 22 and the second port 51d faces the opening of the discharge passage 21, thereby communicating the discharge passage 21 and the supply and exhaust passage 22 through the inside.

[0070] The spring seat 54 is annular and has a flange 54a provided on the outer periphery at the left end in FIG. 2 and an annular guide 54b protruding in the axial direction from the outer periphery at the left end in FIG. 2. The spring seat 54 is fitted onto the inner periphery at the left end in FIG. 2 of the sleeve 51, so that the flange 54a abuts against the left end of the sleeve 51.

[0071] 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. In detail, the first valve body 52 includes a cylindrical body 52a in sliding contact with the inner circumference of the sleeve 51, a valve head 52b provided at the right end of the body 52a in Fig. 2 and having a conical surface facing the first valve seat 51b in the axial direction, a spring fitting portion 52c protruding from the left end of the body 52a in Fig. 2 and having an outer diameter smaller than that of the body 52a, and a rod portion 52d extending leftward from the left end of the spring fitting portion 52c in Fig. 2 and having an outer diameter smaller than that of the spring fitting portion 52c.

[0072] 2 inside the sleeve 51 and separates the valve head 52b from the first valve seat 51b, thereby connecting the discharge passage 21 to the supply and discharge passage 22. The first valve body 52 is provided with a groove 52e formed along the axial direction on the outer periphery of the body 52a over the entire length of the body 52a, and does not close the inner periphery of the sleeve 51 even when inserted into the sleeve 51, and connects the discharge passage 21 to the supply and discharge passage 22 through the groove 52e when the valve is open.

[0073] The first spring 53 has one end fitted into 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 Fig. 2, and the other end inserted into the guide 54b of the spring seat 54 and abutting against an 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 constantly urges the first valve body 52 toward the first valve seat 51b to seat it on the first valve seat 51b.

[0074] In the first valve 50 thus configured, when the pressure in the discharge passage 21 becomes higher than the pressure in the supply and discharge passage 22, the first spring 53 contracts and the first valve body 52 moves back to the left in FIG. 2 within the sleeve 51 to open, thereby communicating the discharge passage 21 with the supply and discharge passage 22. On the other hand, when the pressure in the supply and discharge passage 22 becomes higher than the pressure in the discharge passage 21, the first valve body 52 is pressed against the first valve seat 51b by the first spring 53 and the pressure in the supply and discharge passage 22 to close, thereby blocking the discharge passage 21 with the supply and discharge passage 22. In addition, when the first spring 53 contracts due to the thrust of the solenoid 32 via the second valve 60, the first valve body 52 moves back to the left in FIG. 2 within the sleeve 51 to open, thereby communicating the discharge passage 21 with the supply and discharge passage 22.

[0075] The second valve 60 includes a second valve seat 61d disposed between the discharge passage 21 and the return passage 23, a second valve body 62 disposed 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 a direction such that it seats on the second valve seat 61d.

[0076] 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 Fig. 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 side opposite the sleeve, and forms the second valve seat 61d at the inner periphery of the flange portion 61b at the left end in Fig. 2. The valve seat member 61 also includes a port 61e that penetrates the small diameter cylindrical portion 61c in the radial direction. The valve seat member 61 thus constructed has a screw portion 61f on the outer periphery of the large diameter cylindrical portion 61a, which is screw-connected to the screw portion 6c5 provided in the valve hole 6c2. When screw-connected to the valve hole 6c2, the sleeve 51 and the spring seat 54 are pressed against the bottom of the valve hole 6c2, and fixed in 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 is in close contact with 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 into the step portion 6c3 of the valve housing 6c, and the inside of the small diameter cylindrical portion 61c communicates with the first port 51c and the second port 51d through the inside of the sleeve 51. Thus, the return passage 23 communicates with the discharge passage 21 and the supply and exhaust 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.

[0077] The second valve body 62 is inserted into the sleeve 51 on the right side of the annular protrusion 51a in Fig. 2 so as to be axially movable. In detail, the second valve body 62 includes a cylindrical body 62a in sliding contact with the inner circumference of the sleeve 51, a valve head 62b provided at the right end of the body 62a in Fig. 2 and having a conical surface facing the second valve seat 61d in the axial direction, a spring fitting portion 62c protruding from the left end of the body 62a in Fig. 2 and having an outer diameter smaller than that of the body 62a, and a rod portion 62d extending leftward from the left end of the spring fitting portion 62c in Fig. 2 and having an outer diameter smaller than that of the spring fitting portion 52c and the inner diameter of the annular protrusion 51a of the sleeve 51.

[0078] 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 the second valve body 62 moves leftward in Fig. 2 within the sleeve 51 to separate the valve head 62b from the second valve seat 61d, it connects the discharge passage 21 to the return passage 23. The second valve body 62 has a groove 62e formed along the axial direction on the outer periphery of the body portion 62a over the entire length of the body portion 62a, and does not close the inner periphery of the sleeve 51 even when inserted into the sleeve 51, and connects the discharge passage 21 to the return passage 23 through the groove 62e when the valve is open.

[0079] 2, in a state in which the valve head 62b is seated on the second valve seat 61d, the second valve body 62 moves the left end of the rod portion 62d in FIG. 2 away from the first valve body 52 and moves leftward in the sleeve 51 so that 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 inside the sleeve 51 after the rod portion 62d comes into contact with the first valve body 52, it can push the first valve body 52 to the left. The first valve body 52 pushed by the second valve body 62 in this manner moves leftward inside the sleeve 51 from the position where the valve head 52b is seated on the first valve seat 51b, and moves the valve head 52b away 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 part, 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, thereby preventing incorrect assembly.

[0080] One end of the second spring 63 is fitted into the outer periphery of the spring fitting portion 62c of the second valve body 62 and abuts against the left end of the body portion 62a in Fig. 2, and the other end is abutted against the right end of the annular protrusion 51a of the sleeve 51 in Fig. 2, and is interposed in a compressed state between the second valve body 62 and the annular protrusion 51a. Therefore, the second spring 63 constantly urges the second valve body 62 toward the second valve seat 61d to seat it on the second valve seat 61d.

[0081] The solenoid 32 as an actuator includes a frame 32a screwed to the inner circumference 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 fixed core and a cylindrical second fixed core (not shown) inserted into the frame 32a with a space therebetween in the axial direction, a movable core (not shown) housed in the frame 32a between the first fixed core and the second fixed core so as to be movable in the axial direction and connected to the push rod 32b, and a coil attached to the outer circumference of the first fixed core and the second fixed core and housed in the frame 32a. A screw portion 32a1 screwed to a screw portion 6c4 formed on the inner circumference of the solenoid mounting hole 6c1 is provided on the outer circumference of the left end of the frame 32a in FIG. 2, and the solenoid 32 is attached to the valve housing 6c by inserting the left side of the frame 32a in FIG. 2 into the solenoid mounting hole 6c1. Incidentally, even in a specific switching valve V, the actuator may be a direct acting actuator other than the solenoid 32.

[0082] 2, 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 that pushes the second valve body 62 to the left in FIG. 2 through the push rod 32b.

[0083] A specific switching valve V is configured as described above. Next, the operation of the switching valve V will be described. In a non-energized state, the solenoid 32 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 biased 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 biased 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 and 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 receives the pressure of the pump chamber P through the discharge passage 21 and separates 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 cut off communication between the discharge passage 21 and the return passage 23.

[0084] Next, the operation of the switching valve V when half the maximum current is supplied to the solenoid 32 will be described. In the 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 through the push rod 32b overcomes the spring force of the second spring 63, so that the second valve body 62 moves to the left, but does not abut against the first valve body 52, or does not displace the first valve body 52 even if it abuts against it. Therefore, in this state, the second valve 60 is in an open state, and the discharge passage 21 and the return passage 23 are communicated, while the first valve 50 is closed. In this state, the discharge passage 21 and the return passage 23 are communicated by the opening of the second valve 60, so that even if the pump chamber P is communicated with 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 unloaded position, connecting the discharge passage 21 to the return passage 23 but cutting off communication between the discharge passage 21 and the supply / discharge passage 22.

[0085] Further, the operation of the switching valve V when the maximum current is supplied to the solenoid 32 will be described. In the energized state where 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 increases, and the amount of movement of the second valve body 62 to the left in FIG. 2 increases, so that the second valve body 62 abuts against the first valve body 52, and the second valve body 62 and the first valve body 52 both move to the left, and the first valve 50 and the second valve 60 both open. Therefore, in this state, the discharge passage 21, the supply and discharge passage 22, and the return passage 23 are mutually communicated. As described above, in the state where the solenoid 32 is energized to supply the maximum current, the specific switching valve V takes the discharge position and mutually communicates the discharge passage 21, the supply and discharge passage 22, and the return passage 23.

[0086] In this manner, depending on the current supply state of the solenoid 32, the specific switching valve V takes one of three 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 keeping the vehicle height constant, thereby preventing the compression damping force of the shock absorber D with 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.

[0087] As described above, a specific switching valve V in this embodiment comprises a first valve 50 that is installed between the discharge passage 21 and the supply and discharge passage 22 and allows only the flow of liquid from the discharge passage 21 to the supply and discharge passage 22, a second valve 60 that is capable of switching between communication and blocking between the discharge passage 21 and the return passage 23, is arranged in series with the first valve 50, and is biased to a position where it blocks 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.

[0088] 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 a single solenoid 32 is used to apply thrust to the first valve 50 and the second valve 60 to open and close the first valve 50 and the second valve 60. This makes the switching valve V lightweight and compact, improving the mountability of the shock absorber D with vehicle height adjustment function on a saddle-type vehicle, and also reduces manufacturing costs, making it inexpensive.

[0089] In addition, 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 body 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 urges the first valve body 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 body 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 urges the second valve body 62 in a direction to seat it on the second valve seat 61d. and a second spring 63 which biases the valve body 52 in a direction such that the first valve body 52 is seated on the first valve seat 51b and the second valve body 62 is seated on the second valve seat 61d, 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 in which the solenoid 32 does not apply thrust to the first valve body 52 or the second valve body 62, a unload position in which the solenoid 32 applies thrust only to the second valve body 62, and a discharge position in which the solenoid 32 applies thrust to the second valve body 62 and also applies thrust to the first valve body 52 via the second valve body 62.

[0090] 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, thus simplifying the structure. Also, by sharing the same parts for the first valve body 52 and the second valve body 62, it is possible to prevent incorrect assembly when assembling the switching valve V.

[0091] Although the preferred embodiment of the present invention has been described in detail above, modifications, variations and changes can be made without departing from the scope of the appended claims. [Explanation of symbols]

[0092] DESCRIPTION OF SYMBOLS 1 cylinder, 2 piston rod, 3 piston, 7c fixed spring holder, 10 movable spring holder, 20 suction passage, 21 discharge passage, 22 supply / exhaust 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 height adjustment function, J···Jack, P···Pump chamber, R1···Rebound side chamber, R2···Compression side chamber, S···Suspension spring, T···Tank, V···Switching valve

Claims

1. 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 that expands and contracts in accordance with the expansion and contraction of the shock absorber body; A tank for storing liquid; a suspension spring interposed between a movable spring bearing arranged on an outer periphery of the cylinder so as to be movable in an axial direction 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 to and discharged from the jack chamber; a suction passage that allows only the flow of liquid from the tank toward the pump chamber; a discharge passage connected to the pump chamber; A supply and exhaust passage connected to the jack chamber; a return passage connected to the tank; a switching valve having a supply position that allows only 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 one another. A shock absorber with a vehicle height adjustment function.

2. a relief passage communicating the jack chamber and the tank; 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 to allow the liquid to flow from the jack chamber to the tank.

2. The shock absorber with vehicle height adjustment function according to claim 1.

3. The switching valve is a first valve disposed between the discharge passage and the supply / discharge passage to allow liquid to flow only from the discharge passage to the supply / discharge passage; a second valve capable of switching between communication and blocking between the discharge passage and the return passage, the second valve being disposed in series with the first valve and biased to a position blocking the discharge passage and the return passage; an actuator disposed on the opposite side of the second valve to the first valve; 2. The shock absorber with vehicle height adjustment function according to claim 1.

4. The first valve is a first valve seat disposed between the discharge passage and the supply / discharge passage; a first valve body arranged on a supply / discharge passage side of the first valve seat and capable of being seated on and removed from the first valve seat; a first spring that biases the first valve body in a direction to seat the first valve body on the first valve seat, The second valve is a second valve seat disposed between the discharge passage and the return passage; a second valve body arranged on a discharge passage side of the second valve seat and capable of being seated on and removed from the second valve seat; a second spring that biases the second valve body in a direction to seat the second valve body on the second valve seat, 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 spaced apart from each other, The switching valve is The actuator is switched between a state in which it applies no thrust to the first valve body and the second valve body and takes the supply position, a state in which it applies thrust only to the second valve body and takes the unload position, and a state in which it applies thrust to the second valve body and also applies thrust to the first valve body via the second valve body and takes the discharge position.

4. The shock absorber with vehicle height adjustment function according to claim 3.

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