Valve and cylinder device

Abstract

To provide a valve and a cylinder device suitable for the use of the valve which applies resistance to one flow and does not apply resistance to the other flow at the time of opening the valve without increasing the number of components and costs.SOLUTION: A valve V of the present invention includes: a valve sea member 20 having an annular valve seat 20d; a valve body 21 having an annular seat part 21b which can be seated to and removed from the valve seat 20d; a coil spring (urging member) 22 that urges the valve body 21 against the valve seat member 20; and a restriction flow path Pr formed in a state where the valve body 21 is inserted into the valve seam member 20. In a valve-opening state where the seat part 21b is away from the valve seat 20d, the valve body 21 is released from the valve seat member 20 to be fully opened in a flow from the valve seat member side to the valve body side, and in a flow from the valve seat side to the valve seat member side, a resistance is applied by the restriction flow path Pr in a state where at least a part of the valve body 21 is inserted into the valve seat member 20.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a valve and a cylinder device.

Background Art

[0002] Valves are used, for example, in cylinder devices such as shock absorbers and gas springs, and are set in passages that connect the working chambers provided in the cylinder device to each other or connect the working chamber and a tank that stores liquid.

[0003] Such a valve includes, for example, a valve seat, a valve body that can be separated from and seated on the valve seat, a spring that biases the valve body in the direction of seating on the valve seat, and a spool that separates the valve body from the valve seat against the biasing force of the spring by the action of hydraulic pressure. When the valve body pushed by the spool is separated from the valve seat to open the valve, there is one that communicates the working chamber and the tank (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a conventional valve, when the valve is opened, the working chambers communicate with each other or the working chamber and the tank communicate, but it hardly provides any resistance to the flow of the liquid regardless of the direction of the liquid flow. Therefore, a conventional valve cannot provide resistance according to the direction of the liquid flowing through the valve when the valve is opened.

[0006] In some cases, depending on the cylinder device, it may be desired to slow down the operation during one of the extension operation and the contraction operation while making the operation sensitive during the other. To achieve this, it is only necessary to provide resistance to the flow of the liquid from the working chamber to the tank and not provide resistance to the flow of the liquid from the tank to the working chamber. However, in a conventional valve, it is not possible to provide resistance according to the direction of the flow of the liquid passing through the valve when the valve is opened. Therefore, it is necessary to provide a valve that provides resistance to the flow of the liquid from the working chamber to the tank in parallel with the conventional valve, which increases the number of parts and the cost.

[0007] Therefore, an object of the present invention is to provide a valve that provides resistance to the flow in one direction but not to the flow in the other direction when the valve is opened, and a cylinder device suitable for using the valve, without causing an increase in the number of parts and cost.

Means for Solving the Problem

[0008] To solve the above problems, the valve of the present invention includes a valve seat member having an annular valve seat at one end in the axial direction, which is cylindrical, a valve body having an annular seat portion that can be seated and separated from the valve seat, a biasing member that biases the valve body toward the valve seat member, and a restricted flow path formed in a state where the valve body is inserted into the valve seat member. When the valve is opened and the seat portion is separated from the valve seat, the entire valve body exits from the valve seat member and fully opens with respect to the flow from the valve seat member side to the valve body side, and at least a part of the valve body is inserted into the valve seat member to provide resistance by the restricted flow path with respect to the flow from the valve body side to the valve seat member side.

[0009] According to the valve configured as described above, it can function alone as a check valve with respect to the flow of the liquid in one direction and as a valve that provides resistance to the flow of the liquid in the other direction.

[0010] Further, the valve body in the valve may have a head that can enter and exit the valve seat member, and the restricted flow path in the valve may be formed by an annular gap between the outer periphery of the head of the valve body and the inner periphery of the valve seat member. According to the valve configured in this way, since an annular gap is formed between the head and the valve seat member, they are non-contact with each other. Therefore, when the valve body moves axially with respect to the valve seat member and the head enters and exits the valve seat member, the head does not interfere with the valve seat member, so the valve can be smoothly opened and closed.

[0011] Furthermore, the valve may include a centering member that centers the valve body with respect to the valve seat member while allowing axial movement of the valve body. According to the valve provided with the centering member for centering the valve body in this way, when the head of the valve body enters and exits the valve seat member, the valve body can move axially without axial misalignment, so there is no risk of the head biting the inner peripheral surface of the valve seat member, and smooth axial movement of the valve body is guaranteed, and the valve can be smoothly opened and closed.

[0012] The cylinder device also includes a cylinder, a piston movably inserted into the cylinder and partitioning the inside of the cylinder into an extension chamber and a compression chamber, and a rod movably inserted into the cylinder and connected to the piston. One of the extension chamber and the compression chamber is open to the atmosphere, and the other is filled with liquid. The cylinder device further includes an elastic body, a tank whose interior is partitioned into a gas chamber and a liquid chamber, a communication passage connecting the liquid chamber to the other of the extension chamber and the compression chamber, and a valve provided in the communication passage. According to the cylinder device configured in this way, the operation of either extension or contraction can be slowed down, and not only can the operating speed be made polar depending on the operating direction, but also since only one valve is required, an increase in the number of parts and cost can be suppressed.

[0013] The cylinder device may be used such that the elastic body is bridged between the body of a saddle-type vehicle and a swing arm that is swingable with respect to the body of the saddle-type vehicle and holds the rear wheel. According to the cylinder device configured in this way, the vehicle height on the rear wheel side of the saddle-type vehicle can be adjusted by opening and closing the valve.

[0014] Furthermore, in the cylinder device, when the pressure side chamber is opened to the atmosphere and the extension side chamber is filled with liquid, the valve has a valve body installed in the communication passage facing the valve seat member in the liquid chamber on the extension side, and when the expansion and contraction body extends, it resists the flow of the liquid by the restriction flow path, while it may be fully opened when the expansion and contraction body contracts. According to the cylinder device configured in this way, by the valve opening operation of the valve, when lowering the vehicle height on the rear wheel side during acceleration of the straddle-type vehicle, the valve resists the flow of the liquid to reduce the speed at which the vehicle height decreases, improving the handling stability. Moreover, when the vehicle height rises during braking, the valve does not resist the flow of the liquid, and the expansion and contraction body contracts promptly, causing the vehicle height to rise quickly, improving the vehicle body stability during braking.

Advantages of the Invention

[0015] According to the valve of the present invention, without causing an increase in the number of parts and cost, it can function as a valve that resists the flow in one direction during valve opening, and can also function as a valve that does not resist the flow in the other direction. In addition, the cylinder device is optimal for the use of the valve.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0017] Based on the embodiments shown in the figures, the present invention will be described. As shown in FIG. 1, a cylinder device C equipped with a valve V in one embodiment includes a telescopic body 1, a tank 10, a communication passage 16 that communicates between the inside of the telescopic body 1 and the tank 10, and a valve V provided in the communication passage 16.

[0018] As shown in FIG. 2, the telescopic body 1 in the cylinder device C is rotatably connected to the lower end of a shock absorber D interposed between the vehicle body B of a straddle-type vehicle M and a wheel W and the vehicle body B of the straddle-type vehicle M, and is bridged between a link plate P and a swing arm S that is swingable with respect to the vehicle body B of the straddle-type vehicle M and holds the wheel W.

[0019] The shock absorber D is a telescopic type shock absorber and although not shown in detail, it includes a cylinder and a rod that can enter and exit the cylinder. When the rod moves relative to the cylinder in the axial direction during expansion and contraction, it exerts a damping force that prevents its own expansion and contraction. The upper end of the shock absorber D is rotatably attached to the vehicle body B in the longitudinal direction of the vehicle body B, and the lower end of the shock absorber D is rotatably attached to the link plate P in the longitudinal direction of the vehicle body B. The link plate P is triangular, and the vicinity of each vertex is hinged to the vehicle body B, the lower end of the shock absorber D, and one end of the telescopic body 1, respectively. Specifically, the front connection point of the link plate P is hinged to the vehicle body B, the rear connection point of the link plate P is hinged to the lower end of the shock absorber D, and the central connection point of the link plate P is hinged to one end of the telescopic body 1. The swing arm S has a front end that is hinged to the vehicle body B so as to be rotatable in the vertical direction, holds the wheel W rotatably on the rear end side, and is swingable in the vertical direction with respect to the vehicle body B. Also, the other end of the telescopic body 1 is hinged to the middle part of the swing arm S.

[0020] Therefore, when the telescopic body 1 is rod-shaped and does not expand or contract, when the swing arm S rotates upward in FIG. 2 with respect to the vehicle body B and the wheel W tries to approach the vehicle body B, the link plate P rotates upward with respect to the vehicle body B and compresses the shock absorber D. Thus, the relative movement of the wheel W with respect to the vehicle body B is suppressed by the damping force generated by the shock absorber D. Also, when the telescopic body 1 is rod-shaped and does not expand or contract, when the swing arm S rotates downward in FIG. 2 with respect to the vehicle body B and the wheel W tries to move away from the vehicle body B, the link plate P rotates downward with respect to the vehicle body B and extends the shock absorber D. Thus, the relative movement of the wheel W with respect to the vehicle body B is suppressed by the damping force generated by the shock absorber D. Therefore, the shock absorber D suppresses the relative movement between the wheel W and the vehicle body B due to the vibration input during the running of the saddle-type vehicle M, improving the riding comfort of the vehicle.

[0021] On the other hand, when the cylinder device C extends the telescopic body 1, it rotates the swing arm S upward in FIG. 2 with the connection point to the vehicle body B as a fulcrum, so that the wheel W approaches the vehicle body B and the vehicle height of the saddle-type vehicle M decreases. When the telescopic body 1 is contracted, it rotates the swing arm S downward in FIG. 2 with the connection point to the vehicle body B as a fulcrum, so that the wheel W moves away from the vehicle body B and the vehicle height of the saddle-type vehicle M increases.

[0022] Hereinafter, the valve V and the cylinder device C will be described in detail. The telescopic body 1 includes a cylinder 2, a piston 3 that is movably inserted into the cylinder 2 and divides the inside of the cylinder 2 into an extension chamber R1 and a compression chamber R2, and a rod 4 that is movably inserted into the cylinder 2 and connected to the piston 3.

[0023] As shown in FIG. 1, the cylinder 2 is a bottomed cylindrical shape and includes an eye-type bracket 2b that is hinged to the link plate P at the bottom 2a. An annular rod guide 5 is attached to the open end at the right end in FIG. 1. The piston 3 includes an annular seal ring 3a and an annular piston ring 3b that are in sliding contact with the inner circumference of the cylinder 2 on the outer circumference. The piston 3 divides the inside of the cylinder 2 into the extension chamber R1 and the compression chamber R2 and can smoothly move axially, i.e., in the left-right direction in FIG. 1, inside the cylinder 2.

[0024] The rod 4 is inserted into the inner circumference of the rod guide 5 and inserted into the cylinder 2. The left end in FIG. 1, which is the tip, is connected to the piston 3, and the right end in FIG. 1, which is the base end, protrudes outside the cylinder 2. The cylinder 2 is provided with a hole 2c that communicates the pressure chamber R2 on the left side of the piston 3 inside the cylinder 2 to the outside of the cylinder 2, and the pressure chamber R2 is open to the atmosphere. Further, a connection hole 2d for mounting a joint 6 facing the extension chamber R1 is provided on the side portion of the open end side of the cylinder 2.

[0025] The tank 10 includes a bottomed cylindrical tank body 11 having a bottom 11a, a cap 12 that closes the open end of the tank body 11, and a free piston 13 that is movably accommodated in the tank body 11 in the axial direction and divides the inside of the tank body 11 into a liquid chamber L on the bottom side and a gas chamber G on the open side.

[0026] The tank body 11 includes a valve hole 11b that penetrates in the vertical direction in FIG. 1, which is the direction perpendicular to the axial direction of the bottom 11a, and a port 11c that communicates the inside of the valve hole 11b with the liquid chamber L. Further, as shown in FIG. 3, the inner diameter of the valve hole 11b is smaller on the lower side, and a stepped portion 11b1 is provided below the port 11c in FIG. 3.

[0027] A joint 14 for connecting the pipe 15 to the tank body 11 is attached to the open end of the lower end of the valve hole 11b. One end of the pipe 15 is connected to the cylinder 2 via the joint 6, the other end is connected to the tank 10 via the joint 14, and the extension chamber R1 and the valve hole 11b are in communication. Thus, in the present embodiment, a communication passage 16 that communicates the extension chamber R1 and the liquid chamber L of the tank 10 is formed by the pipe 15, the valve hole 11b, and the port 11c.

[0028] The cap 12 includes a cylindrical mounting portion 12a that is screwed to the inner periphery of the right end in FIG. 1 of the tank body 11, a valve case 12b that is cylindrical and disposed on the inner peripheral side of the mounting portion 12a, an annular lid portion 12c that connects the right ends of the mounting portion 12a and the valve case 12b in FIG. 1, and an air valve 12d that is mounted on the inner periphery of the valve case 12b and enables injection of gas into the air chamber G from the outside, and closes the opening end of the tank body 11.

[0029] The mounting portion 12a includes a seal ring 12e on the outer periphery and a screw portion 12f provided to the right of the seal ring 12e in FIG. 1. When the cap 12 is inserted into the inner periphery of the opening end of the tank body 11 and screwed to the tank body 11 using the screw portion 12f, the seal ring 12e is brought into close contact with the inner periphery of the tank body 11 to seal the inside of the tank 10 and prevent leakage of gas from the inside of the tank 10.

[0030] The free piston 13 is accommodated in the tank body 11 so as to be axially movable, partitions the liquid chamber L and the air chamber G in the tank body 11, and transmits the pressure in the air chamber G to the liquid chamber L. Compressed gas is enclosed in the air chamber G, and the pressure in the air chamber G is always equal to or higher than the atmospheric pressure.

[0031] And a valve V is accommodated in the valve hole 11b in the tank body 11. In the present embodiment, as shown in FIG. 3, the valve V includes a valve seat member 20 accommodated in the valve hole 11b, a valve body 21 that can be seated and separated from the valve seat member 20, a coil spring 22 as a biasing member that biases the valve body 21 toward the valve seat member 20, a centering member 23 that centers the valve body 21, a push rod 24 that presses the valve body 21 against the biasing force of the coil spring 22 by an external operation to separate the valve body 21 from the valve seat member 20, and an annular nut member 25 that is screwed to the opening end of the upper end of the valve hole 11b in FIG. 3.

[0032] The valve seat member 20 is cylindrical, and includes a large-diameter portion 20a having a large outer diameter and fitted into the valve hole 11b, a small-diameter portion 20b having a small outer diameter on the lower side in FIG. 3 of the large-diameter portion 20a, and a hole 20c penetrating the large-diameter portion 20a in the radial direction. A valve seat 20d is formed by the annular lower end surface at the lower end of the small-diameter portion 20b, which is one end in the axial direction. Further, on the outer periphery of the large-diameter portion 20a and above the hole 20c in FIG. 3, a sealing ring 20e is mounted, which seals the space between the valve seat member 20 and the tank body 11 by closely contacting the wall surface forming the valve hole 11b of the tank body 11 when the valve seat member 20 is accommodated in the valve hole 11b.

[0033] The centering member 23 is cylindrical, and includes a fitting portion 23a that fits on the outer periphery of the small-diameter portion 20b of the valve seat member 20 and also fits into the valve hole 11b, a housing cylinder 23b that extends axially from the lower end in FIG. 3 of the fitting portion 23a and has a smaller outer diameter than the fitting portion 23a and houses the valve body 21 and the coil spring 22 inward, and a centering portion 23c provided in a flange shape from the lower end in FIG. 3 of the housing cylinder 23b to the inner peripheral side.

[0034] The centering member 23 is inserted into the valve hole 11b until the outer periphery of the lower end in FIG. 3 of the fitting portion 23a abuts against the step portion 11b1 in the valve hole 11b. The valve seat member 20 fits the small-diameter portion 20b of the valve seat member 20 into the inner periphery of the fitting portion 23a of the centering member 23, and makes the step portion at the boundary between the large-diameter portion 20a and the small-diameter portion 20b on the outer periphery abut against the upper end in FIG. 3 of the fitting portion 23a. When accommodated in the valve hole 11b, the port 11c of the tank body 11 and the hole 20c face each other, and the inside of the valve seat member 20 communicates with the liquid chamber L of the tank 10.

[0035] The housing cylinder 23b includes a stopper 23b1 which is an annular step portion formed on the inner circumference by making the inner diameter on the lower side in FIG. 3 smaller in the middle, and a hole 23b2 that penetrates radially upward of the stopper 23b1 in FIG. 3. Further, the outer diameter of the housing cylinder 23b is made smaller than the inner diameter on the lower side in FIG. 3 of the step portion 11b1 of the valve hole 11b. Therefore, when the centering member 23 is housed in the valve hole 11b as described above, an annular gap is formed between the housing cylinder 23b and the wall surface of the valve hole 11b. Inside the centering member 23, it communicates with the liquid chamber L through the inside of the valve seat member 20, and is communicated with the extension chamber R1 through the hole 23b2, the valve hole 11b, and the pipe 15.

[0036] The inner diameter of the housing cylinder 23b is slightly smaller than the outer diameter of the small-diameter portion 20b of the valve seat member 20, but can be arbitrarily set as long as it does not prevent the movement of the valve body 21 and the seating and unseating on the valve seat 20d, which will be described later.

[0037] The valve body 21 includes a columnar head 21a that can enter and exit the small-diameter portion 20b of the valve seat member 20, an annular seat portion 21b that is continuous downward in FIG. 3 behind the head 21a and can be seated and unseated on the valve seat 20d, a columnar spring fitting portion 21c that extends from the lower side in FIG. 3 of the seat portion 21b, and a columnar shaft portion 21d that extends from the lower end in FIG. 3 of the spring fitting portion 21c and has an outer diameter smaller than that of the spring fitting portion 21c and is in sliding contact with the inner circumference of the centering portion 23c of the centering member 23.

[0038] The outer diameter of the head 21a is smaller than the inner diameter of the small-diameter portion 20b. When the valve body 21 inserts the head 21a into the small-diameter portion 20b, a restricted flow path Pr is formed in the annular gap between the outer circumference of the head 21a and the inner circumference of the small-diameter portion 20b.

[0039] The seat portion 21b has an outer diameter larger than the outer diameter of the head 21a and the inner diameter of the valve seat 20d, and has a tapered surface whose outer diameter becomes smaller toward the upper side in FIG. 3, and the tapered surface faces the valve seat 20d. Further, the outer diameter of the seat portion 21b is larger than the inner diameter of the stopper 23b1 of the housing cylinder 23b, and is smaller than the inner diameter on the upper side in FIG. 3 of the stopper 23b1 of the housing cylinder 23b.

[0040] Therefore, the valve body 21 can move in the axial direction which is the vertical direction in FIG. 3 while being accommodated in the accommodation cylinder 23b. When the seat portion 21b is seated on the valve seat 20d, the tapered surface abuts against the inner peripheral edge of the valve seat 20d and the valve body 21 closes the communication passage 16. Further, when the valve body 21 moves downward in FIG. 3 from the position where the seat portion 21b is seated on the valve seat 20d and the lower end of the seat portion 21b in FIG. 3 abuts against the stopper 23b1, the entire head portion 21a is completely withdrawn from the valve seat member 20, and the communication passage 16 is maximally opened. In this state, since the head portion 21a of the valve body 21 has completely come out of the small-diameter portion 20b, a restricted flow path Pr is not formed between the valve body 21 and the valve seat member 20, and the valve V does not impose much resistance on the flow of the liquid passing between the valve body 21 and the valve seat 20d.

[0041] Even if the seat portion 21b is separated from the valve seat 20d, if a part of the head portion 21a is inserted into the small-diameter portion 20b, the valve body 21 forms a restricted flow path Pr with the valve seat member 20 and imposes resistance on the flow of the liquid passing through the restricted flow path Pr.

[0042] The outer diameter of the spring fitting portion 21c is smaller than the inner diameter of the accommodation cylinder 23b, forming an annular space for accommodating the coil spring 22 as a biasing member between the spring fitting portion 21c and the accommodation cylinder 23b, and fitting to the inner periphery of the coil spring 22 to guide the expansion and contraction of the coil spring 22. The coil spring 22 is interposed between the lower end of the seat portion 21b in FIG. 3 and the upper end of the centering portion 23c of the centering member 23 in FIG. 3, and constantly biases the valve body 21 in the direction of seating on the valve seat 20d. Therefore, in a state where no external force acts on the valve body 21, the valve body 21 is biased by the coil spring 22 and positioned at the position of seating on the valve seat 20d. Note that since the coil spring 22 is fitted to the spring fitting portion 21c, it can apply a stable biasing force to the valve body 21 without eccentricity.

[0043] The shaft portion 21d at the rear end in the valve body 21 is slidably inserted into the inner circumference of the centering portion 23c in the centering member 23, and the valve body 21 can move in the direction of approaching and separating without axial deviation with respect to the valve seat member 20 fitted into the fitting portion 23a of the centering member 23. Therefore, the head portion 21a of the valve body 21 can smoothly enter and exit the small-diameter portion 20b of the valve seat member 20 without interfering with the small-diameter portion 20b when entering and exiting the small-diameter portion 20b.

[0044] The push rod 24 is rod-shaped and includes a body 24a having a flange 24b that can abut against the end face of the large-diameter portion 20a of the valve seat member 20 in the middle, and the lower side of the flange 24b in FIG. 3 is slidably inserted into the large-diameter portion 20a. The push rod 24 also includes a pressing shaft 24c extending axially from the lower end of the body 24a and facing the upper end of the head portion 21a of the valve body 21 in FIG. 3. The body 24a does not face the hole 20c even when it penetrates into the large-diameter portion 20a until the flange 24b abuts against the upper end of the large-diameter portion 20a of the valve seat member 20 in FIG. 3, so that the hole 20c is not blocked. The pressing shaft 24c has an outer diameter sufficiently smaller than the outer diameter of the head portion 21a of the valve body 21 so as not to provide resistance when liquid passes between the pressing shaft 24c and the small-diameter portion 20b when the pressing shaft 24c penetrates into the small-diameter portion 20b.

[0045] When the push rod 24 penetrates into the large-diameter portion 20a until the flange 24b abuts against the upper end of the large-diameter portion 20a of the valve seat member 20 in FIG. 3, the push rod 24 abuts against the head portion 21a of the valve body 21 and pushes the valve body 21 downward in FIG. 3, causing the valve body 21 to separate from the valve seat 20d while leaving a part of the head portion 21a in the small-diameter portion 20b.

[0046] The nut member 25 is cylindrical, has a threaded portion 25a on its outer periphery, and is screwed to the upper inner periphery of the valve hole 11b in FIG. 3 and attached to the tank body 11. When the nut member 25 is attached to the valve hole 11b, it abuts against the upper outer periphery of the large-diameter portion 20a of the valve seat member 20 in FIG. 3, and sandwiches the valve seat member 20 and the centering member 23 together with the stepped portion 11b1 to fix the valve seat member 20 and the centering member 23 in the valve hole 11b. Further, the nut member 25 has a flange 25b on its inner periphery that axially opposes the flange 24b of the push rod 24. Therefore, the push rod 24 can move in the axial direction in the vertical direction in FIG. 3 within the range from the uppermost position where the flange 24b abuts against the flange 25b of the nut member 25 to the lowermost position where the flange 24b abuts against the upper end of the large-diameter portion 20a of the valve seat member 20 in FIG. 3.

[0047] The push rod 24 is connected via a wire (not shown) to a reverse switch (not shown) provided near the handle of the saddle-type vehicle M. When the push rod 24 is pushed downward in FIG. 3 by the operation of the reverse switch by the driver of the saddle-type vehicle M, the push rod 24 pushes the valve body 21 downward against the biasing force of the coil spring 22, and the valve body 21 separates from the valve seat 20d, and the valve V opens. When the push rod 24 is moved upward in FIG. 3 by the operation of the reverse switch by the driver of the saddle-type vehicle M, the push rod 24 separates from the valve body 21. Therefore, the valve body 21 is pushed upward in FIG. 3 by the biasing force of the coil spring 22 and seats on the valve seat 20d, and the valve V closes. In this way, the valve V is a normally-closed on-off valve that opens when the valve body 21 is pushed by the operation of the push rod 24, and closes when the valve body 21 seats on the valve seat 20d by the biasing force of the coil spring 22 in a state where the pressing force of the push rod 24 does not act.

[0048] The valve V and the cylinder device C are configured as described above, and the operations of the valve V and the cylinder device C will be described below. In the cylinder device C, as described above, the pressure-side chamber R2 is open to the atmosphere, and the extension-side chamber R1 communicates with the liquid chamber L pressurized by the air chamber G of the tank 10 via the communication passage 16. When the valve V is closed without operating the push rod 24 in the valve V and without applying a force to separate the valve element 21 from the valve seat 20d from the push rod 24, the communication between the extension-side chamber R1 and the liquid chamber L is cut off and the liquid exchange between the extension-side chamber R1 and the liquid chamber L becomes impossible. Therefore, the cylinder device C cannot perform an extension operation or a contraction operation and becomes rod-shaped. On the other hand, when the push rod 24 in the valve V is operated to separate the valve element 21 from the valve seat 20d by the push rod 24 and the valve V is opened, the extension-side chamber R1 and the liquid chamber L communicate with each other and the liquid exchange between the extension-side chamber R1 and the liquid chamber L becomes possible. Therefore, the cylinder device C becomes in a state where it can expand and contract. Further, when the valve V is opened, the pressure-side chamber R2 is open to the atmosphere, and the pressure of the air chamber G propagates to the extension-side chamber R1 and presses the piston 3 toward the pressure-side chamber R2 side. Therefore, the cylinder device C tends to contract during the opening of the valve V when no external force is applied.

[0049] Based on the above, the operation of the cylinder device C applied to the straddle-type vehicle M will be described. First, when the valve V is closed, the cylinder device C becomes rod-shaped and cannot perform an extension operation or a contraction operation. Therefore, when the swing arm S swings in the vertical direction in FIG. 2 with respect to the vehicle body B due to the input of vibration from the road surface during the running of the straddle-type vehicle M, the cylinder device C transmits the swing of the swing arm S to the link plate P. Thus, the shock absorber D expands and contracts to generate a damping force, and the vibration of the vehicle body B is suppressed.

[0050] When the other party opens the valve V, a force in the extending direction acts on the expandable body 1 due to the weight of the vehicle body B, and the pressure in the extending chamber R1 becomes greater than the pressure in the tank 10. Therefore, the cylinder device C extends to its maximum extent, and the liquid moves from the extending chamber R1 through the communication passage 16 and the valve V to the liquid chamber L of the tank 10. When the cylinder device C extends, the swing arm S rotates in a direction approaching the vehicle body B, and the vertical distance between the vehicle body B and the wheel W decreases. Therefore, the vehicle height of the saddle-type vehicle M decreases by the amount of the decreased distance.

[0051] Here, when the valve V is opened, the push rod 24 separates the valve body 21 from the valve seat 20d but does not completely pull the head 21a out from inside the small-diameter portion 20b of the valve seat member 20. Thus, a restricted flow path Pr is formed between the head 21a and the small-diameter portion 20b. When the cylinder device C extends and the liquid goes from the extending chamber R1 to the liquid chamber L, the high-pressure liquid pressed by the piston 3 passes between the valve body 21 and the valve seat 20d from the valve body 21 side toward the valve seat member 20 side and moves to the low-pressure liquid chamber L. Therefore, when the side of the valve body 21 facing the valve seat 20d is taken as the front side and the opposite side as the back side, the valve body 21 is pressed toward the valve seat 20d side by the pressure in the extending chamber R1, which becomes high pressure on the back side. In this state, the valve body 21 does not move from the position where it is pushed by the push rod 24, and the head 21a remains in a state of penetrating into the small-diameter portion 20b. Therefore, the liquid flowing from the extending chamber R1 to the liquid chamber L passes through the restricted flow path Pr, and the flow of the liquid from the extending chamber R1 to the liquid chamber L is resisted by the restricted flow path Pr.

[0052] In this way, when the valve V is opened, the cylinder device C receives the vehicle weight and the telescopic body 1 exhibits an extension operation. However, since resistance is applied to the flow of the liquid by the restricted flow path Pr, the extension speed becomes slow and it extends slowly, and the vehicle height of the straddle-type vehicle M also slowly decreases. Lowering the vehicle height on the rear wheel side of the straddle-type vehicle M lowers the vehicle center of gravity, suppresses the front wheel lift during acceleration, and improves the acceleration performance. Therefore, the driver can intentionally lower the vehicle height and improve the acceleration performance by operating the reverse switch to open the valve V during acceleration. And when lowering the vehicle height, since the valve V can resist the flow of the liquid and slow down the extension operation of the cylinder device C, a sharp change in the vehicle body posture can be suppressed and the handling stability can be improved. When the valve V is closed while the cylinder device C is extended and the vehicle height is lowered, the liquid cannot flow back and forth between the extension chamber R1 and the liquid chamber L, and the cylinder device C becomes a rod-shaped body and can maintain the state where the vehicle height is lowered.

[0053] Also, when the straddle-type vehicle M decelerates with the valve V kept open, if the vehicle body B pitches forward and the vehicle body B and the wheels W are separated, the force in the extension direction acting on the telescopic body 1 becomes smaller and the pressure in the tank 10 becomes larger than the pressure in the extension chamber R1, so a force in the contraction direction acts. Therefore, the cylinder device C contracts and the liquid moves from the liquid chamber L to the extension chamber R1 through the communication passage 16 and the valve V. As the cylinder device C contracts, the swing arm S rotates in a direction away from the vehicle body B, and the vertical distance between the vehicle body B and the wheels W increases. The vehicle height of the straddle-type vehicle M increases by the amount of the increased distance.

[0054] When the cylinder device C contracts and the liquid flows from the liquid chamber L to the extending chamber R1, the liquid in the liquid chamber L under the pressure of the air chamber G passes between the valve body 21 and the valve seat 20d from the valve seat member 20 side toward the valve body 21 side and moves to the low-pressure extending chamber R1. Therefore, the valve body 21 receives the pressure of the high-pressure liquid chamber L from the front side and retreats to a position regulated by the stopper 23b1 from the valve seat 20d until the head 21a completely exits from the small-diameter portion 20b, maximizing the opening area of the valve V. When the head 21a exits from the valve seat member 20, the restricted flow path Pr is not formed between the head 21a and the valve seat member 20, and the valve V allows the flow of the liquid from the liquid chamber L to the extending chamber R1 with almost no resistance.

[0055] Thus, when the liquid flows from the liquid chamber L to the extending chamber R1, unlike the case when the liquid flows from the extending chamber R1 to the liquid chamber L, it gives almost no resistance to the flow of the liquid. Therefore, the cylinder device C contracts promptly, and the vehicle height of the straddle-type vehicle M rises quickly. When the vehicle height on the rear-wheel side of the straddle-type vehicle M is increased, the lifting of the rear wheels from the road surface during braking is suppressed, improving the vehicle body stability during braking. Therefore, when the driver operates the reverse switch to open the valve V during braking, the driver can intentionally raise the vehicle height to improve the vehicle body stability during braking.

[0056] When raising the vehicle height, since the valve V gives almost no resistance to the flow of the liquid, the cylinder device C can contract promptly, so the lifting of the wheel W from the road surface during braking can be suppressed immediately. If the valve V is closed while the cylinder device C contracts and the vehicle height is raised, the liquid cannot flow back and forth between the extending chamber R1 and the liquid chamber L, and the cylinder device C becomes a rod-shaped body, maintaining the vehicle height in the raised state.

[0057] As described above, the valve V of the present embodiment includes a valve seat member 20 that is cylindrical and has an annular valve seat 20d at one end in the axial direction, a valve body 21 that has an annular seat portion 21b that can be seated and separated from the valve seat 20d, a coil spring (biasing member) 22 that biases the valve body 21 toward the valve seat member 20, and a restricted flow path Pr that is formed in a state where the valve body 21 is inserted into the valve seat member 20. When the valve is opened and the seat portion 21b is separated from the valve seat 20d, the entire valve body 21 exits from the valve seat member 20 and fully opens with respect to the flow from the valve seat member side to the valve body side, and at least a part of the valve body 21 is inserted into the valve seat member 20 to provide resistance to the flow from the valve body side to the valve seat member side by the restricted flow path Pr.

[0058] According to the valve V configured as described above, when the valve is opened, with respect to the flow from the valve seat member side to the valve body side, the head 21a completely exits from the valve seat member 20 and hardly provides resistance to the flow of the liquid passing through without forming the restricted flow path Pr. On the other hand, with respect to the flow from the valve body side to the valve seat member side, resistance can be provided to the flow of the liquid passing through by the restricted flow path Pr. In this way, the valve V can function as a check valve for the flow of liquid in one direction alone and as a valve that provides resistance to the flow of liquid in the other direction. Therefore, according to the valve V of the present embodiment, in the conventional valve, a check valve and a valve that provides resistance had to be provided in parallel, but the functions of a check valve and a valve that provides resistance can be realized alone. As described above, according to the valve V of the present embodiment, a valve that provides resistance to the flow in one direction but not to the flow in the other direction when the valve is opened can be realized without causing an increase in the number of parts and cost.

[0059] In addition, as described above, the valve seat member 20 includes a large-diameter portion 20a and a small-diameter portion 20b, but it only needs to have at least the small-diameter portion 20b that has the valve seat 20d at one end in the axial direction and allows the head 21a of the valve body 21 to enter and exit. Therefore, the other structure of the valve seat member 20 can be arbitrarily designed and changed. Further, although the biasing member is the coil spring 22, it may be a spring or an elastic body other than the coil spring as long as it can bias the valve body 21 in the direction of seating on the valve seat 20d.

[0060] Also, in the valve V of the present embodiment, the valve body 21 has a head 21a that can enter and exit the valve seat member 20, and the restricted flow path Pr is formed by an annular gap between the outer periphery of the head 21a of the valve body 21 and the inner periphery of the valve seat member 20. According to the valve V configured in this way, since an annular gap is formed between the head 21a and the valve seat member 20 and they are in non-contact with each other, when the valve body 21 moves axially with respect to the valve seat member 20 and the head 21a enters and exits the valve seat member 20, the head 21a does not interfere with the valve seat member 20, so the valve can be smoothly opened and closed.

[0061] Furthermore, in the valve V of the present embodiment, a centering member 23 is provided that centers the valve body 21 with respect to the valve seat member 20 while allowing axial movement of the valve body 21. According to the valve V provided with the centering member 23 that centers the valve body 21 in this way, when the head 21a of the valve body 21 enters and exits the valve seat member 20, the valve body 21 can move axially without axial misalignment, so there is no risk of the head 21a biting the inner peripheral surface of the valve seat member 20, and smooth axial movement of the valve body 21 is guaranteed, and the valve can be smoothly opened and closed.

[0062] In the valve V of the present embodiment, a shaft portion 21d is provided on the side of the valve body 21 opposite to the valve seat, and the centering member 23 is provided with an annular centering portion 23c into which the shaft portion 21d is slidably inserted. However, a hole may be provided along the axial direction on the valve body 21 side, and a shaft inserted into the hole of the valve body 21 may be provided on the centering member 23 side to center the valve body 21 with respect to the valve seat member 20, or the centering member 23 may be provided on the tank body 11. Also, a hole may be provided along the axial direction at the tip of the head 21a, and a shaft inserted into the hole of the head 21a may be provided at the tip of the push rod 24, and this shaft may be used as the centering member.

[0063] However, as described above, when the centering member 23 is cylindrical and fits into the small-diameter portion 20b of the valve seat member 20 to accommodate the valve body 21, and the centering portion 23c of the centering member 23 functions as a spring seat for a coil spring (biasing member) 22 that centers and biases the valve body 21, the components constituting the valve V can be pre-assembled and accommodated in the valve hole 11b, facilitating the assembly of the valve V. Also, since the centering member 23 and the valve body 21 can be assembled based on the valve seat member 20, there is an advantage that it is easier to center the valve body 21 with respect to the valve seat member 20.

[0064] Incidentally, in the above description, the restricted flow path Pr is formed by the annular gap between the outer periphery of the head 21a of the valve body 21 and the inner periphery of the valve seat member 20. However, as in the valve V1 of the first modification of the embodiment shown in FIG. 4, the outer periphery of the head 21a is brought into sliding contact with the inner periphery of the small-diameter portion 20b of the valve seat member 20, and a groove 21a1 is provided along the axial direction on the outer periphery of the head 21a. Until the seat portion 21b is separated from the valve seat 20d and the head 21a is completely withdrawn from the inside of the small-diameter portion 20b, the restricted flow path Pr may be formed by the groove 21a1 provided in the head 21a. In this case, since the valve body 21 is centered with respect to the valve seat member 20 by the centering member 23, even if the head 21a is withdrawn from the inner periphery of the valve seat member 20, the head 21a can enter the valve seat member 20 again and the valve V can be closed. Therefore, when the centering member 23 is provided, the restricted flow path Pr may be provided by the groove 21a1 formed on the outer periphery of the head 21a in this way. Also, in this case, as in the valve V2 of the second modification shown in FIG. 5, instead of the groove 21a1, a passage 21a2 that opens from the tip of the head 21a and opens to the base end of the head 21a may be formed, and the restricted flow path Pr may be formed by the passage 21a2. When the restricted flow path Pr is formed by the passage 21a2 in this way, until the head 21a is completely withdrawn from the small-diameter portion 20b, the flow path length of the restricted flow path Pr does not change, and the resistance given to the liquid flow by the restricted flow path Pr does not change.

[0065] Furthermore, the cylinder device C of the present embodiment includes a cylinder 2, a piston 3 that is movably inserted into the cylinder 2 and partitions the inside of the cylinder 2 into an extension chamber R1 and a compression chamber R2, and a rod 4 that is movably inserted into the cylinder 2 and connected to the piston 3. The compression chamber R2 is open to the atmosphere, and the extension chamber R1 is filled with a liquid. The cylinder device C also includes a tank 10 whose interior is partitioned into a gas chamber G and a liquid chamber L, a communication passage 16 that connects the liquid chamber L to the extension chamber R1, and a valve V provided in the communication passage 16.

[0066] In the present embodiment, the cylinder device C has the compression chamber R2 open to the atmosphere, and when the valve V is opened, the pressure in the gas chamber G acts on the extension chamber R1, so that a spring force that contracts the elastic body 1 can be exerted. Further, when the valve V is opened, the cylinder device C provides resistance to the flow of the liquid from the extension chamber R1 to the liquid chamber L with the restriction flow path Pr, and provides almost no resistance to the flow of the liquid from the liquid chamber L to the extension chamber R1. Therefore, when the elastic body 1 extends due to an external force, the operation becomes slow and the elastic body 1 extends slowly. When the elastic body 1 contracts spontaneously or due to an external force, the operation becomes sensitive and the elastic body 1 can be quickly contracted.

[0067] Note that if the compression chamber R2 is opened to the atmosphere, the extension chamber R1 and the liquid chamber L are connected by the communication passage 16, and the orientation of the valve V installed in the communication passage 16 is reversed, then when the valve V is opened, the cylinder device C can exert a spring force that contracts the elastic body 1. Also, when the valve V is opened, the cylinder device C provides resistance to the flow of the liquid from the liquid chamber L to the extension chamber R1 with the restriction flow path Pr, and provides almost no resistance to the flow of the liquid from the extension chamber R1 to the liquid chamber L. Therefore, when the elastic body 1 contracts spontaneously or due to an external force, the operation becomes slow and the elastic body 1 contracts slowly. When the elastic body 1 extends due to an external force, the operation becomes sensitive and the elastic body 1 can be quickly extended.

[0068] Further, while releasing the extension chamber R1 to the atmosphere and connecting the compression chamber R2 and the liquid chamber L with the communication passage 16, a resistance may be provided by the restriction flow path Pr to the flow of the liquid from the compression chamber R2 toward the liquid chamber L when the valve V is opened, and almost no resistance may be provided to the flow of the liquid from the liquid chamber L toward the compression chamber R2. By doing so, the cylinder device C exerts a spring force for extending the telescopic body 1 when the valve V is opened, and when the telescopic body 1 contracts by an external force, the operation becomes slow and the telescopic body 1 contracts slowly, and when the telescopic body 1 extends spontaneously or by an external force, the operation becomes sensitive and the telescopic body 1 can be quickly extended.

[0069] Furthermore, while releasing the extension chamber R1 to the atmosphere and connecting the compression chamber R2 and the liquid chamber L with the communication passage 16, a resistance may be provided by the restriction flow path Pr to the flow of the liquid from the liquid chamber L toward the compression chamber R2 when the valve V is opened, and almost no resistance may be provided to the flow of the liquid from the compression chamber R2 toward the liquid chamber L. By doing so, the cylinder device C exerts a spring force for extending the telescopic body 1 when the valve V is opened, and when the telescopic body 1 extends spontaneously or by an external force, the operation becomes slow and the telescopic body 1 extends slowly, and when the telescopic body 1 contracts by an external force, the operation becomes sensitive and the telescopic body 1 can be quickly contracted.

[0070] In this way, the cylinder device C can slow down either the extension or the contraction operation, not only can it give polarity to the operation speed depending on the operating direction, but also can suppress an increase in the number of parts and cost, and the valve V is optimal for application to the cylinder device C that needs to have polarity in the operation speed.

[0071] And further, the telescopic body 1 in the cylinder device C of the present embodiment is bridged between the vehicle body B of the saddle-riding type vehicle M and a swing arm S that is swingable with respect to the vehicle body B of the saddle-riding type vehicle M and holds the wheel W. The cylinder device C configured in this way can adjust the vehicle height on the rear wheel side of the saddle-riding type vehicle M by opening and closing the valve V.

[0072] In addition, in the cylinder device C of the present embodiment, the pressure chamber R2 is open to the atmosphere and the extension chamber R1 is filled with liquid. The valve V has a valve body 21 installed in the extension chamber R1 with a valve seat member 20 facing the liquid chamber L in the communication passage 16. When the telescopic body 1 extends, it resists the flow of the liquid by the restriction flow path Pr, while when the telescopic body 1 contracts, it fully opens. According to the cylinder device C configured in this way, by the valve opening operation of the valve V, when the vehicle height on the rear wheel side is lowered during acceleration of the straddle-type vehicle M, the valve V resists the flow of the liquid to reduce the speed at which the vehicle height decreases, thereby improving the handling stability. Moreover, when the vehicle height increases during braking, the valve V does not resist the flow of the liquid, and the telescopic body 1 contracts promptly, causing the vehicle height to rise quickly, thereby improving the vehicle body stability during braking.

[0073] Note that the valve V can be used as a valve for various hydraulic circuits other than the cylinder device C described above, and the cylinder device C may also be used for applications other than the cylinder device for adjusting the vehicle height of the straddle-type vehicle M.

[0074] As described above, the preferred embodiments of the present invention have been described in detail. However, modifications, deformations, and changes are possible without departing from the scope of the claims.

Explanation of Reference Numerals

[0075] 1... Telescopic body, 2... Cylinder, 3... Piston, 4... Rod, 10... Tank, 16... Communication passage, 20... Valve seat member, 20d... Valve seat, 21... Valve body, 21a... Head, 21b... Seat portion, 22... Coil spring (biasing member), 23... Centering member, B... Vehicle body, C... Cylinder device, G... Air chamber, L... Liquid chamber, M... Straddle-type vehicle, P... Link plate, Pr... Restriction flow path, R1... Extension chamber, R2... Pressure chamber, S... Swing arm, V, V1, V2... Valves, W... Wheel

Claims

1. A valve seat member that is cylindrical and has an annular valve seat at one end in the axial direction, A valve body having an annular seat portion that can be seated and disengaged from the valve seat, A biasing member that biases the valve body toward the valve seat member, And a restricted flow path formed in a state where the valve body is inserted into the valve seat member, When the valve opens and the seat portion is separated from the valve seat, the entire valve body exits from the valve seat member and fully opens with respect to the flow from the valve seat member side to the valve body side, and at least a part of the valve body is inserted into the valve seat member with respect to the flow from the valve body side to the valve seat member side, and resistance is applied by the restricted flow path. A valve characterized by the above.

2. The valve body has a head that can enter and exit the valve seat member, The restricted flow path is formed by an annular gap between the outer circumference of the head of the valve body and the inner circumference of the valve seat member. The valve according to claim 1, characterized by the above.

3. Comprising a centering member that centers the valve body with respect to the valve seat member while allowing axial movement of the valve body. The valve according to claim 2, characterized by the above.

4. A cylinder, a piston that is movably inserted into the cylinder and divides the inside of the cylinder into an extension chamber and a compression chamber, and a rod that is movably inserted into the cylinder and connected to the piston, and one of the extension chamber and the compression chamber is open to the atmosphere, and the other of the extension chamber and the compression chamber is filled with liquid. An elastic body, A tank whose interior is partitioned into an air chamber and a liquid chamber, A communication passage that communicates the liquid chamber with the other of the extension chamber and the compression chamber, And a valve according to any one of claims 1 to 3 provided in the communication passage. A cylinder device characterized by the above.

5. The elastic body is spanned between the body of a saddle-riding type vehicle and a swing arm that is swingable with respect to the body of the saddle-riding type vehicle and holds the rear wheel. The cylinder device according to claim 4, characterized by the above.

6. The compression chamber is open to the atmosphere and the extension chamber is filled with liquid. The valve is installed in the communication passage with the valve body facing the extension chamber and the valve seat member facing the liquid chamber, and resists the flow of liquid by the restricted flow path during the extension operation of the elastic body, while fully opening during the contraction operation of the elastic body. The cylinder device according to claim 5, characterized by the above.

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