Valve and cylinder device

Abstract

A valve (V) of the present invention is provided with: a valve seat member (20) having an annular valve seat (20d); a valve body (21) having an annular seat part (21b) that can be seated on / separated from the valve seat (20d); a biasing member (22) that biases the valve body (21) toward the valve seat member (20); and a restrictive flow passage (Pr) that is formed in a state in which the valve body (21) is inserted into the valve seat member (20). During valve opening when the seat part (21b) is separated from the valve seat (20d), flow from the valve seat member side to the valve body side causes the valve body (21) to be pulled out from the valve seat member (20) and fully opened, and flow from the valve body side to the valve seat member side is restricted by the restrictive flow passage (Pr) in a state in which at least a part of the valve body (21) is inserted into the valve seat member (20).

Description

Valve and Cylinder Devices

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

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

[0003] Such a valve, for example, as disclosed in JP2021-134906A, includes a valve seat, a valve element that can be seated and removed from the valve seat, a spring that urges the valve element toward seating on the valve seat, and a spool that uses hydraulic pressure to move the valve element away from the valve seat against the spring's urging force, and when the valve element is pushed by the spool and moves away from the valve seat to open, the valve connects the operating chamber to the tank (see, for example, Patent Document 1).

[0004] JP2021-134906A

[0005] Conventional valves connect the working chambers or the working chambers to the tank when open, but provide almost no resistance to the flow of liquid regardless of the direction of the liquid flow. Therefore, conventional valves cannot provide resistance according to the direction of the liquid flow passing through the valve when open.

[0006] On the other hand, depending on the cylinder device, there may be cases where it is desired to make the operation slower during either the extension or contraction operation, while making the operation quicker during the other operation. To achieve this, it is necessary to provide resistance to the flow of liquid from the working chamber to the tank, and not provide resistance to the flow of liquid from the tank to the working chamber. However, conventional valves are unable to provide resistance according to the direction of flow of liquid passing through the valve when the valve is open, so it is necessary to install a valve that provides resistance to the flow of liquid from the working chamber to the tank in parallel with the conventional valve, which increases the number of parts and costs.

[0007] Therefore, the present invention aims to provide a valve that provides resistance to flow in one direction but not to flow in the other direction when the valve is open, without increasing the number of parts or costs, and a cylinder device suitable for use with such a valve.

[0008] In order to solve the above problems, the valve of the present invention comprises a cylindrical valve seat member having an annular valve seat at one axial end, a valve disc having an annular seat portion that can be seated on and removed from the valve seat, a biasing member that biases the valve disc toward the valve seat member, and a restricting flow path that is formed when the valve disc is inserted into the valve seat member, and when the seat portion moves away from the valve seat to open the valve, the entire valve disc comes out of the valve seat member and is fully open to prevent a flow from the valve seat member side to the valve disc side, and the restricting flow path provides resistance to a flow from the valve disc side to the valve seat member side with at least a part of the valve disc inserted into the valve seat member.

[0009] A valve configured in this manner can function independently as a check valve for the flow of liquid in one direction, and as a valve that provides resistance to the flow of liquid in the other direction.

[0010] The cylinder device includes a cylinder, a piston movably inserted into the cylinder and dividing the interior of the cylinder into an extension-side chamber and a compression-side chamber, a rod movably inserted into the cylinder and connected to the piston, an expandable body in which one of the extension-side chamber and the compression-side chamber is open to the atmosphere and the other is filled with liquid, a tank whose interior is divided into an air chamber and a liquid chamber, a communication passage connecting the liquid chamber to the other of the extension-side chamber and the compression-side chamber, and a valve provided in the communication passage. The cylinder device configured in this manner not only makes it possible to slow down either the extension or contraction operation and to provide a polarity in the operating speed depending on the operating direction, but also requires only one valve, thereby reducing the number of parts and costs.

[0011] Fig. 1 is a cross-sectional view of a cylinder device according to one embodiment. Fig. 2 is a side view of a saddle-ride type vehicle equipped with the cylinder device according to one embodiment. Fig. 3 is an enlarged cross-sectional view of a valve according to one embodiment. Fig. 4 is a partially enlarged cross-sectional view of a valve according to a first modified example of the embodiment. Fig. 5 is a partially enlarged cross-sectional view of a valve according to a second modified example of the embodiment.

[0012] The present invention will be described based on the embodiment shown in the drawings. As shown in Figure 1, a cylinder device C equipped with a valve V in one embodiment includes an expandable body 1, a tank 10, a communication passage 16 that connects the inside of the expandable body 1 with the tank 10, and a valve V provided in the communication passage 16.

[0013] As shown in Figure 2, the telescopic body 1 in the cylinder device C is spanned across a link plate P that is rotatably connected to the lower end of a shock absorber D interposed between the body B and wheel W of the saddle-riding vehicle M and the body B of the saddle-riding vehicle M, and a swing arm S that is swingable relative to the body B of the saddle-riding vehicle M and holds the wheel W.

[0014] The shock absorber D is a telescopic shock absorber, and although not shown in detail, it is equipped with a cylinder and a rod that can move in and out of the cylinder, and when the rod moves axially relative to the cylinder, it exerts a damping force that prevents the shock absorber itself from expanding or contracting. The upper end of the shock absorber D is attached to the vehicle body B so as to be rotatable in the fore-and-aft direction of the vehicle body B, and the lower end of the shock absorber D is attached to a link plate P so as to be rotatable in the fore-and-aft direction of the vehicle body B. The link plate P is triangular in shape, and the vicinity of each vertex is hingedly connected 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 hingedly connected to the vehicle body B, the rear connection point of the link plate P is hingedly connected to the lower end of the shock absorber D, and the central connection point of the link plate P is hingedly connected to one end of the telescopic body 1. The front end of the swing arm S is hingedly connected to the vehicle body B so as to be rotatable in the vertical direction, and the rear end thereof rotatably holds a wheel W, so that the swing arm S can swing in the vertical direction relative to the vehicle body B. In addition, the other end of the telescopic body 1 is hingedly connected to the middle part of the swing arm S.

[0015] Therefore, when the telescopic body 1 is rod-shaped and does not extend or retract, if the swing arm S rotates upward in Figure 2 relative to the vehicle body B and the wheel W approaches the vehicle body B, the link plate P rotates upward relative to the vehicle body B and compresses the shock absorber D, and the damping force generated by the shock absorber D suppresses movement of the wheel W relative to the vehicle body B. Also, when the telescopic body 1 is rod-shaped and does not extend or retract, if the swing arm S rotates downward in Figure 2 relative to the vehicle body B and the wheel W attempts to move away from the vehicle body B, the link plate P rotates downward relative to the vehicle body B and extends the shock absorber D, and the damping force generated by the shock absorber D suppresses movement of the wheel W relative to the vehicle body B. Therefore, the shock absorber D suppresses relative movement between the wheel W and the vehicle body B due to vibrations input while the saddle-type vehicle M is traveling, improving the ride comfort of the vehicle.

[0016] On the other hand, when the telescopic body 1 is extended, the cylinder device C rotates the swing arm S upward in FIG. 2 with the point of connection 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-riding type vehicle M is lowered, and when the telescopic body 1 is retracted, the swing arm S rotates downward in FIG. 2 with the point of connection 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-riding type vehicle M is raised.

[0017] The following provides a detailed description of the valve V and the cylinder device C. The telescopic body 1 includes a cylinder 2, a piston 3 movably inserted into the cylinder 2 and dividing the interior of the cylinder 2 into an extension-side chamber R1 and a compression-side chamber R2, and a rod 4 movably inserted into the cylinder 2 and connected to the piston 3.

[0018] 1, the cylinder 2 is cylindrical and has a bottom, and is provided at its bottom 2a with an eye-shaped bracket 2b that is hingedly connected to a link plate P. An annular rod guide 5 is attached to the open end on the right side in FIG. 1. The piston 3 is provided on its outer periphery with an annular seal ring 3a and an annular piston ring 3b that slide against the inner periphery of the cylinder 2. The piston 3 divides the interior of the cylinder 2 into an expansion-side chamber R1 and a compression-side chamber R2, and can move smoothly within the cylinder 2 in the left-right direction in FIG. 1, which corresponds to the axial direction.

[0019] The rod 4 is inserted into the cylinder 2 by being inserted through the inner periphery of the rod guide 5, with its tip (left end in FIG. 1 ) connected to the piston 3 and its base (right end in FIG. 1 ) protruding outside the cylinder 2. The cylinder 2 is provided with a hole 2c that connects the compression-side chamber R2 inside the cylinder 2 to the left of the piston 3 to the outside of the cylinder 2, and the compression-side chamber R2 is open to the atmosphere. In addition, a connection hole 2d is provided on the side of the open end of the cylinder 2 to which a joint 6 facing the extension-side chamber R1 is attached.

[0020] The tank 10 is configured to include 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 accommodated within the tank body 11 and is axially movable, dividing the interior of the tank body 11 into a liquid chamber L on the bottom side and an air chamber G on the open side.

[0021] The tank body 11 has a valve hole 11b that penetrates the bottom 11a in the vertical direction in Fig. 1, which is perpendicular to the axial direction, and a port 11c that connects the inside of the valve hole 11b with the liquid chamber L. As shown in Fig. 3, the inner diameter of the valve hole 11b is smaller on the lower side, and a step 11b1 is provided below the port 11c in Fig. 3.

[0022] A joint 14 that connects the pipe 15 to the tank body 11 is attached to the open end at the lower end of the valve hole 11b. One end of the pipe 15 is connected to the cylinder 2 via the joint 6, and the other end is connected to the tank 10 via the joint 14, thereby connecting the expansion-side chamber R1 and the valve hole 11b. In this manner, in the present embodiment, the pipe 15, the valve hole 11b, and the port 11c form a communication passage 16 that connects the expansion-side chamber R1 and the liquid chamber L of the tank 10.

[0023] The cap 12 includes a cylindrical mounting portion 12a that is screwed onto the inner periphery of the right end of the tank body 11 in Figure 1, a cylindrical valve case 12b that is arranged on the inner periphery 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 Figure 1, and an air valve 12d that is attached to the inner periphery of the valve case 12b and allows gas to be injected into the air chamber G from outside, and closes the open end of the tank body 11.

[0024] The mounting portion 12a has a seal ring 12e on its outer periphery and a threaded portion 12f provided to the right of the seal ring 12e in Figure 1. When the cap 12 is inserted into the inner periphery of the open end of the tank body 11 and screwed to the tank body 11 using the threaded portion 12f, the seal ring 12e is brought into tight contact with the inner periphery of the tank body 11, sealing the inside of the tank 10 and preventing gas from leaking from inside the tank 10.

[0025] The free piston 13 is housed in the tank body 11 so as to be movable in the axial direction, and divides the tank body 11 into a liquid chamber L and an air chamber G, and transmits the pressure in the air chamber G to the liquid chamber L. Compressed gas is sealed in the air chamber G, and the pressure in the air chamber G is always equal to or higher than atmospheric pressure.

[0026] A valve V is accommodated in the valve hole 11b of the tank body 11. In this embodiment, as shown in Fig. 3, the valve V includes a valve seat member 20 accommodated in the valve hole 11b, a valve disc 21 that is removably seated on the valve seat member 20, a coil spring 22 as a biasing member that biases the valve disc 21 toward the valve seat member 20, an aligning member 23 that aligns the valve disc 21, a push rod 24 that is externally operated to press the valve disc 21 against the biasing force of the coil spring 22, thereby separating the valve disc 21 from the valve seat member 20, and an annular nut member 25 that is screwed to the open end of the valve hole 11b at the upper end in Fig. 3.

[0027] The valve seat member 20 is cylindrical and includes a large-diameter portion 20a having a large outer diameter that fits into the valve hole 11b, a small-diameter portion 20b having a smaller outer diameter below the large-diameter portion 20a in Fig. 3, and a hole 20c that penetrates the large-diameter portion 20a in the radial direction, and a valve seat 20d is formed by the annular lower end surface of the lower end of the small-diameter portion 20b, which is one end in the axial direction. In addition, a seal ring 20e is attached to the outer periphery of the large-diameter portion 20a and above the hole 20c in Fig. 3, so that when the valve seat member 20 is accommodated in the valve hole 11b, it comes into close contact with the wall surface that forms the valve hole 11b of the tank body 11 and seals the gap between the valve seat member 20 and the tank body 11.

[0028] The aligning member 23 is cylindrical and includes a fitting portion 23a that fits onto 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 of the fitting portion 23a in Figure 3, has an outer diameter smaller than that of the fitting portion 23a, and houses the valve body 21 and the coil spring 22 inside, and an aligning portion 23c that is provided in a flange-like shape from the lower end of the housing cylinder 23b in Figure 3 toward the inner periphery.

[0029] The aligning member 23 is inserted into the valve hole 11b until the outer periphery of the fitting portion 23a at the lower end in Fig. 3 abuts against the step 11b1 of the valve hole 11b. When the valve seat member 20 is accommodated in the valve hole 11b with the small-diameter portion 20b of the valve seat member 20 fitted into the inner periphery of the fitting portion 23a of the aligning member 23 and the step on the outer periphery between the large-diameter portion 20a and the small-diameter portion 20b abutting against the upper end of the fitting portion 23a in Fig. 3, the port 11c of the tank body 11 and the hole 20c face each other, and the interior of the valve seat member 20 communicates with the liquid chamber L of the tank 10.

[0030] The accommodating cylinder 23b includes a stopper 23b1, which is an annular step formed on the inner periphery by reducing the inner diameter of the lower side in FIG. 3 , and a hole 23b2 that penetrates radially above the stopper 23b1 in FIG. 3 . The outer diameter of the accommodating cylinder 23b is smaller than the inner diameter of the valve hole 11b below the step 11b1 in FIG. 3 . Therefore, when the aligning member 23 is accommodated in the valve hole 11b as described above, an annular gap is formed between the accommodating cylinder 23b and the wall surface of the valve hole 11b. The interior of the aligning member 23 communicates with the liquid chamber L through the valve seat member 20 and with the expansion-side chamber R1 through the hole 23b2, the valve hole 11b, and the piping 15.

[0031] 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 set arbitrarily as long as it does not interfere with the movement of the valve element 21 (described later) and its movement onto and off the valve seat 20d.

[0032] The valve body 21 includes a cylindrical 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 connected to the rear of the head 21a at the bottom in FIG. 3 and can be seated on and removed from the valve seat 20d, a cylindrical spring fitting portion 21c that extends from the bottom of the seat portion 21b in FIG. 3, and a cylindrical shaft portion 21d that extends from the bottom end of the spring fitting portion 21c in FIG. 3, has an outer diameter smaller than that of the spring fitting portion 21c, and slides against the inner periphery of the alignment portion 23c of the alignment member 23.

[0033] The outer diameter of the head 21a is smaller than the inner diameter of the small diameter portion 20b, and when the head 21a is inserted into the small diameter portion 20b, the valve body 21 forms a restricting flow path Pr in the annular gap between the outer periphery of the head 21a and the inner periphery of the small diameter portion 20b.

[0034] The seat portion 21b has an outer diameter larger than the outer diameter of the head portion 21a and the inner diameter of the valve seat 20d, and has a tapered surface whose outer diameter decreases toward the top in Fig. 3, with the tapered surface facing the valve seat 20d. The outer diameter of the seat portion 21b is larger than the inner diameter of the stopper 23b1 of the housing tube 23b, but smaller than the inner diameter of the housing tube 23b above the stopper 23b1 in Fig. 3.

[0035] Therefore, while housed within the housing cylinder 23b, the valve element 21 can move in the axial direction, which is the up-and-down direction in Fig. 3, and 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, causing the valve element 21 to close the communication passage 16. Furthermore, when the valve element 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 removed from the valve seat member 20, thereby fully opening the communication passage 16. In this state, because the head portion 21a of the valve element 21 is completely removed from the small diameter portion 20b, no restricting flow path Pr is formed between the valve element 21 and the valve seat member 20, and the valve V does not provide much resistance to the flow of liquid passing between the valve element 21 and the valve seat 20d.

[0036] Even if the seat portion 21b is separated from the valve seat 20d, if the head portion 21a is partially inserted into the small diameter portion 20b, the valve body 21 forms a restricted flow path Pr between itself and the valve seat member 20, and provides resistance to the flow of liquid passing through the restricted flow path Pr.

[0037] The outer diameter of the spring fitting portion 21c is smaller than the inner diameter of the housing tube 23b, forming an annular space between the spring fitting portion 21c and the housing tube 23b to accommodate the coil spring 22 serving as a biasing member, and fitting around 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 aligning portion 23c of the aligning member 23 in FIG. 3, and constantly biases the valve disc 21 in a direction to seat it on the valve seat 20d. Therefore, when no external force is applied to the valve disc 21, the valve disc 21 is biased by the coil spring 22 to a position where it seats on the valve seat 20d. Note that, because the coil spring 22 is fitted into the spring fitting portion 21c, it can apply a stable biasing force to the valve disc 21 without becoming eccentric.

[0038] The shaft portion 21d at the rear end of the valve disc 21 is slidably inserted into the inner periphery of the aligning portion 23c of the aligning member 23, and the valve disc 21 can move toward or away from the valve seat member 20, which is fitted into the fitting portion 23a of the aligning member 23, without axial wobble. Therefore, the head portion 21a of the valve disc 21 can smoothly move in and out of the small diameter portion 20b of the valve seat member 20 without interfering with the small diameter portion 20b.

[0039] The push rod 24 is rod-shaped and includes a main body 24a provided with a flange 24b that can abut against the end face of the large-diameter portion 20a of the valve seat member 20. The portion below the flange 24b in FIG. 3 is slidably inserted into the large-diameter portion 20a, and a pressing shaft 24c that extends axially from the lower end of the main body 24a and faces the upper end of the head 21a of the valve element 21 in FIG. 3. Even when the main body 24a enters the large-diameter portion 20a until the flange 24b abuts against the upper end of the large-diameter portion 20a in FIG. 3, the main body 24a does not face the hole 20c, so that the hole 20c is not blocked. The pressing shaft 24c has an outer diameter that is sufficiently smaller than the outer diameter of the head 21a of the valve element 21, so that when it enters the small-diameter portion 20b, it does not provide resistance when liquid passes between the pressing shaft 24c and the small-diameter portion 20b.

[0040] Furthermore, when the push rod 24 enters the large diameter portion 20a of the valve seat member 20 until the flange 24b abuts against the upper end of the large diameter portion 20a in FIG. 3, the push rod 24 abuts against the head 21a of the valve body 21 and pushes the valve body 21 downward in FIG. 3, causing the valve body 21 to move away from the valve seat 20d while leaving a portion of the head 21a within the small diameter portion 20b.

[0041] The nut member 25 is cylindrical and has a threaded portion 25a on its outer periphery. The nut member 25 is threadedly coupled to the inner periphery of the upper end of the valve hole 11b (see FIG. 3 ) and attached to the tank body 11. When attached to the valve hole 11b, the nut member 25 abuts against the outer periphery of the large-diameter portion 20a of the valve seat member 20 (see FIG. 3 ), sandwiching the valve seat member 20 and the aligning member 23 together with the step portion 11b1 to secure the valve seat member 20 and the aligning member 23 within the valve hole 11b. The nut member 25 also has a flange 25b on its inner periphery that faces the flange 24b of the push rod 24 in the axial direction. The push rod 24 can thus move axially (up and down in FIG. 3 ) 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 (see FIG. 3 ).

[0042] The push rod 24 is connected via a wire (not shown) to a lever switch (not shown) provided near the handlebars of the saddle-riding vehicle M. When the driver of the saddle-riding vehicle M operates the lever switch to push the push rod 24 downward in Fig. 3, the push rod 24 pushes the valve body 21 downward in Fig. 3 against the biasing force of the coil spring 22, causing the valve body 21 to separate from the valve seat 20d and open the valve V. When the driver of the saddle-riding vehicle M operates the lever switch to move the push rod 24 upward in Fig. 3, the push rod 24 separates from the valve body 21, causing the biasing force of the coil spring 22 to push the valve body 21 upward in Fig. 3 and seat it on the valve seat 20d, closing the valve V. In this way, valve V is a normally closed valve that opens when the valve body 21 is pushed by operating the push rod 24, but closes when the pushing force of the push rod 24 is not acting, as the valve body 21 seats on the valve seat 20d due to the biasing force of the coil spring 22.

[0043] The valve V and the cylinder device C are configured as described above, and the operation of the valve V and the cylinder device C will be described below. In the cylinder device C, as described above, the compression-side chamber R2 is open to the atmosphere, and the extension-side chamber R1 is connected to the liquid chamber L pressurized by the air chamber G of the tank 10 via the communication passage 16. When the push rod 24 of the valve V is not operated and the push rod 24 does not apply a force to separate the valve body 21 from the valve seat 20d, and the valve V is closed, the communication between the extension-side chamber R1 and the liquid chamber L is cut off, and fluid exchange between the extension-side chamber R1 and the liquid chamber L is disabled. As a result, the cylinder device C is unable to extend or retract and becomes rod-shaped. On the other hand, when the push rod 24 of the valve V is operated to separate the valve body 21 from the valve seat 20d with the push rod 24, and the valve V is opened, the extension-side chamber R1 and the liquid chamber L are connected, and fluid exchange between the extension-side chamber R1 and the liquid chamber L is enabled. As a result, the cylinder device C is able to extend or contract. Furthermore, when the valve V is open, the compression side chamber R2 is open to the atmosphere, and the pressure of the air chamber G is transmitted to the extension side chamber R1, pressing the piston 3 toward the compression side chamber R2. Therefore, the cylinder device C tends to contract while the valve V is open in the absence of any external force.

[0044] Based on the above, we will now explain the operation of the cylinder device C applied to the saddle-riding type vehicle M. First, when the valve V is closed, the cylinder device C becomes rod-shaped and cannot extend or retract. Therefore, when vibrations are input from the road surface while the saddle-riding type vehicle M is traveling and the swing arm S swings in the vertical direction in Figure 2 relative to the vehicle body B, the cylinder device C transmits the swing of the swing arm S to the link plate P, causing the shock absorber D to expand and contract, generating a damping force and suppressing vibration of the vehicle body B.

[0045] On the other hand, when the valve V is opened, a force in the extension direction acts on the telescopic body 1 due to the weight of the vehicle body B, and the pressure in the extension-side chamber R1 becomes greater than the pressure in the tank 10, so the cylinder device C extends to its maximum extent, and liquid moves from the extension-side chamber R1 to the liquid chamber L of the tank 10 via the communication passage 16 and the valve V. 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, and the vehicle height of the saddle-ride type vehicle M decreases by the amount of the decrease in distance.

[0046] When the valve V is opened, the push rod 24 separates the valve element 21 from the valve seat 20d but does not allow the head 21a to completely come out from inside the small diameter portion 20b of the valve seat member 20, so that a restricted flow path Pr is formed between the head 21a and the small diameter portion 20b. When the cylinder device C extends and liquid flows from the extension-side chamber R1 to the liquid chamber L, the high-pressure liquid pressed by the piston 3 passes between the valve element 21 and the valve seat 20d from the valve element 21 side toward the valve seat member 20 side and moves to the low-pressure liquid chamber L. Therefore, if the side of the valve element 21 facing the valve seat 20d is the front side and the opposite side is the back side, the valve element 21 is pressed toward the valve seat 20d by the pressure of the extension-side chamber R1, which is high pressure on the back side, and the valve element 21 does not move from the position where it is pressed by the push rod 24, and the head 21a is maintained in a state where it is inserted into the small diameter portion 20b. Therefore, the liquid flowing from the expansion-side chamber R1 to the liquid chamber L passes through the restrictor flow path Pr, and the flow of the liquid flowing from the expansion-side chamber R1 to the liquid chamber L is resisted by the restrictor flow path Pr.

[0047] In this way, when the valve V is opened, the cylinder device C receives the vehicle weight and the telescopic body 1 performs an extension operation. However, because the restricting flow path Pr provides resistance to the flow of liquid, the extension speed slows down and the extension operation proceeds slowly, resulting in a slower lowering of the vehicle height of the saddle-riding vehicle M. Lowering the vehicle height on the rear wheel side of the saddle-riding vehicle M lowers the center of gravity of the vehicle, suppressing lift of the front wheel during acceleration and improving acceleration performance. Therefore, when accelerating, the driver can intentionally lower the vehicle height and improve acceleration performance by operating the lever switch to open the valve V. Furthermore, when lowering the vehicle height, the valve V provides resistance to the flow of liquid, slowing the extension operation of the cylinder device C, thereby suppressing sudden changes in the vehicle body posture and improving handling stability. If the valve V is closed while the cylinder device C is extended and the vehicle height is lowered, liquid cannot flow back and forth between the extension-side chamber R1 and the liquid chamber L, causing the cylinder device C to become a rod-shaped body and maintaining the vehicle height in a lowered state.

[0048] Furthermore, when the saddle-riding type vehicle M decelerates with the valve V open, the vehicle body B pitches forward and separates from the wheel W, and the force in the extension direction acting on the telescopic body 1 decreases, causing the pressure in the tank 10 to exceed the pressure in the extension-side chamber R1, resulting in a force in the contraction direction, so that the cylinder device C contracts and liquid moves from the fluid chamber L to the extension-side chamber R1 via 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, increasing the vertical distance between the vehicle body B and the wheel W, and the vehicle height of the saddle-riding type vehicle M increases by the amount of this increase in distance.

[0049] When the cylinder device C contracts and liquid flows from the liquid chamber L to the extension-side chamber R1, the liquid in the liquid chamber L, under the pressure of the air chamber G, moves from the valve seat member 20 side toward the valve element 21 side, passing between the valve element 21 and the valve seat 20d, and into the low-pressure extension-side chamber R1. Therefore, the valve element 21 receives pressure from the high-pressure liquid chamber L from the front side and retreats from the valve seat 20d to a position restricted by the stopper 23b1, causing the head portion 21a to completely come out of the small diameter portion 20b, maximizing the opening area of ​​the valve V. When the head portion 21a comes out of the valve seat member 20, no restrictive flow path Pr is formed between the head portion 21a and the valve seat member 20, and the valve V allows the flow of liquid from the liquid chamber L to the extension-side chamber R1 with almost no resistance.

[0050] In this way, when the liquid flows from the liquid chamber L to the extension-side chamber R1, almost no resistance is applied to the flow of the liquid, unlike when the liquid flows from the extension-side chamber R1 to the liquid chamber L, so the cylinder device C contracts quickly and the vehicle height of the saddle-riding type vehicle M is quickly raised. If the vehicle height of the rear wheel side of the saddle-riding type vehicle M is raised, lift-up of the rear wheel from the road surface during braking is suppressed, improving vehicle body stability during braking. Therefore, when braking, the driver can intentionally raise the vehicle height by operating the lever switch to open the valve V, thereby improving vehicle body stability during braking.

[0051] When raising the vehicle height, the valve V provides almost no resistance to the flow of liquid, allowing the cylinder device C to quickly contract, thereby immediately preventing the wheel W from lifting off the road surface during braking. If the valve V is closed while the cylinder device C is contracted and the vehicle height is raised, liquid cannot pass between the expansion-side chamber R1 and the liquid chamber L, and the cylinder device C becomes a rod-shaped body, allowing the vehicle height to be maintained at a raised state.

[0052] As described above, the valve V of this embodiment comprises a cylindrical valve seat member 20 having an annular valve seat 20d at one axial end, a valve disc 21 having an annular seat portion 21b that is able to seat on and separate from the valve seat 20d, a coil spring (biasing member) 22 that biases the valve disc 21 toward the valve seat member 20, and a restricting flow path Pr that is formed when the valve disc 21 is inserted into the valve seat member 20, and when the seat portion 21b moves away from the valve seat 20d to open the valve, the entire valve disc 21 comes out of the valve seat member 20 to fully open the valve disc 21 against the flow from the valve seat member side to the valve disc side, and resistance is provided to the flow from the valve disc side to the valve seat member side by the restricting flow path Pr with at least a portion of the valve disc 21 inserted into the valve seat member 20.

[0053] With the valve V configured in this manner, when the valve is open, the head 21a completely separates from the valve seat member 20, forming no restricting flow path Pr and providing almost no resistance to the flow of liquid passing through it from the valve seat member side to the valve disc side. Meanwhile, the restricting flow path Pr provides resistance to the flow of liquid passing through it from the valve disc side to the valve seat member side. In this way, the valve V can independently function as a check valve for the flow of liquid in one direction and as a valve that provides resistance to the flow of liquid in the other direction. Therefore, while conventional valves require a check valve and a valve that provides resistance in parallel, the valve V of this embodiment can independently function as both a check valve and a valve that provides resistance. As described above, the valve V of this embodiment can provide resistance to the flow in one direction but not the flow in the other direction when the valve is open, without increasing the number of parts or costs.

[0054] While the valve seat member 20 has the large diameter portion 20a and the small diameter portion 20b as described above, it is sufficient that the valve seat member 20 has at least the small diameter portion 20b that has the valve seat 20d at one axial end and allows the head 21a of the valve element 21 to move in and out, and other structural design changes can be made as desired for the valve seat member 20. Furthermore, although the biasing member is the coil spring 22, it may be a spring or elastic body other than a coil spring as long as it is capable of biasing the valve element 21 in the direction of seating it on the valve seat 20d.

[0055] Furthermore, in the valve V of this embodiment, the valve element 21 has a head portion 21a that can move in and out of the valve seat member 20, and the restricting flow path Pr is formed by an annular gap between the outer periphery of the head portion 21a of the valve element 21 and the inner periphery of the valve seat member 20. With the valve V configured in this manner, the annular gap formed between the head portion 21a and the valve seat member 20 prevents them from contacting each other. Therefore, when the valve element 21 moves axially relative to the valve seat member 20 and the head portion 21a moves in and out of the valve seat member 20, the head portion 21a does not interfere with the valve seat member 20, allowing for smooth opening and closing operations.

[0056] Furthermore, the valve V of this embodiment is provided with an aligning member 23 that aligns the valve disc 21 with respect to the valve seat member 20 while allowing the valve disc 21 to move in the axial direction. With the valve V thus provided with the aligning member 23 that aligns the valve disc 21, the valve disc 21 can move in the axial direction without axial wobble when the head 21a of the valve disc 21 moves in and out of the valve seat member 20, so there is no need to worry about the head 21a scraping against the inner peripheral surface of the valve seat member 20, ensuring smooth axial movement of the valve disc 21 and enabling smooth opening and closing operations.

[0057] In the valve V of this embodiment, the shaft portion 21d is provided on the side opposite the valve seat of the valve disc 21, and the aligning member 23 is provided with an annular aligning portion 23c into which the shaft portion 21d is slidably inserted, but a hole may be provided on the valve disc 21 side along the axial direction, and a shaft to be inserted into the hole in the valve disc 21 may be provided on the aligning member 23 side to align the valve disc 21 with the valve seat member 20, or the aligning member 23 may be provided on the tank body 11. Also, a hole may be provided on the tip of the head 21a along the axial direction, and a shaft to be inserted into the hole in the head 21a may be provided on the tip of the push rod 24, and the shaft may serve as the aligning member.

[0058] However, as mentioned above, if the aligning member 23 is cylindrical and fits into the small-diameter portion 20b of the valve seat member 20 to accommodate the valve disc 21, and the aligning portion 23c of the aligning member 23 is configured to align the valve disc 21 and function as a spring retainer for the coil spring (biasing member) 22 that biases the valve disc 21, then the components that make up the valve V can be assembled and accommodated in the valve hole 11b in advance, making assembly of the valve V easier, and since the aligning member 23 and valve disc 21 can be assembled using the valve seat member 20 as a base, there are the advantages that it is easier to align the valve disc 21 with the valve seat member 20.

[0059] In the above description, the restricting flow path Pr is formed by an annular gap between the outer periphery of the head 21a of the valve disc 21 and the inner periphery of the valve seat member 20. However, as in the valve V1 of a first modified example of an embodiment shown in Fig. 4, the outer periphery of the head 21a may be in sliding contact with the inner periphery of the small-diameter portion 20b of the valve seat member 20, and a groove 21a1 may be formed on the outer periphery of the head 21a along the axial direction, so that the restricting flow path Pr is formed by the groove 21a1 formed in the head 21a until the seat portion 21b separates from the valve seat 20d and the head 21a completely leaves the small-diameter portion 20b. In this case, the valve disc 21 is aligned with the valve seat member 20 by the aligning member 23, so that even if the head 21a leaves the inner periphery of the valve seat member 20, the head 21a can re-enter the valve seat member 20 and close the valve V. Therefore, when the aligning member 23 is provided, the restricting flow path Pr may be formed by the groove 21a1 formed on the outer periphery of the head 21a. 5, a passage 21a2 may be formed in place of the groove 21a1, opening from the tip end of the head portion 21a to the base end of the head portion 21a, and the restriction flow path Pr may be formed by the passage 21a2. When the restriction flow path Pr is formed by the passage 21a2 in this manner, the flow path length of the restriction flow path Pr does not change until the head portion 21a is completely removed from the small diameter portion 20b, and the resistance that the restriction flow path Pr provides to the flow of liquid does not change.

[0060] Furthermore, the cylinder device C of this embodiment includes a cylinder 2, a piston 3 that is movably inserted into the cylinder 2 and divides the interior of the cylinder 2 into an extension-side chamber R1 and a compression-side chamber R2, a rod 4 that is movably inserted into the cylinder 2 and connected to the piston 3, an expandable body 1 in which the compression-side chamber R2 is open to the atmosphere and the extension-side chamber R1 is filled with liquid, a tank 10 whose interior is divided into an air chamber G and a liquid chamber L, a communication passage 16 that connects the liquid chamber L to the extension-side chamber R1, and a valve V provided in the communication passage 16.

[0061] In this embodiment, the cylinder device C has the compression-side chamber R2 open to the atmosphere, and when the valve V is opened, the pressure of the air chamber G acts on the extension-side chamber R1, thereby generating a spring force that contracts the telescopic body 1. Furthermore, when the valve V is open, the cylinder device C applies resistance to the flow of liquid from the extension-side chamber R1 to the liquid chamber L through the restrictor flow path Pr, and applies almost no resistance to the flow of liquid from the liquid chamber L to the extension-side chamber R1. Therefore, when an extension operation is performed by an external force, the operation is slow, allowing the telescopic body 1 to be extended slowly, and when a contraction operation is performed spontaneously or by an external force, the operation is quick, allowing the telescopic body 1 to be contracted quickly.

[0062] Furthermore, if the compression-side chamber R2 is released to the atmosphere, the extension-side chamber R1 and the liquid chamber L are connected by the communication passage 16, and the installation direction of the valve V relative to the communication passage 16 is reversed, the cylinder device C will exert a spring force that contracts the telescopic body 1 when the valve V is open, and the valve V will provide resistance to the flow of liquid from the liquid chamber L to the extension-side chamber R1 through the restriction flow path Pr, while providing almost no resistance to the flow of liquid from the extension-side chamber R1 to the liquid chamber L. Therefore, when contracting spontaneously or due to an external force, the operation will be slow, allowing the telescopic body 1 to contract slowly, and when extending due to an external force, the operation will be quick, allowing the telescopic body 1 to extend quickly.

[0063] Alternatively, the expansion-side chamber R1 may be opened to the atmosphere, the compression-side chamber R2 and the liquid chamber L may be connected by the communication passage 16, and when the valve V is open, the restrictor flow path Pr may provide resistance to the flow of liquid from the compression-side chamber R2 to the liquid chamber L, so that almost no resistance is provided to the flow of liquid from the liquid chamber L to the expansion-side chamber R2. In this way, the cylinder device C exerts a spring force that extends the telescopic body 1 when the valve V is open, and operates slowly when contracting due to an external force, thereby slowly contracting the telescopic body 1, and operates quickly when extending spontaneously or due to an external force, thereby quickly extending the telescopic body 1.

[0064] Furthermore, the expansion-side chamber R1 may be opened to the atmosphere, the compression-side chamber R2 and the liquid chamber L may be connected by the communication passage 16, and when the valve V is open, the restrictor flow path Pr may provide resistance to the flow of liquid from the liquid chamber L to the expansion-side chamber R2, and almost no resistance may be provided to the flow of liquid from the compression-side chamber R2 to the liquid chamber L. In this way, the cylinder device C exerts a spring force that extends the telescopic body 1 when the valve V is open, and operates slowly to slowly extend the telescopic body 1 when the telescopic body 1 is expanded spontaneously or by an external force, and operates quickly to quickly contract the telescopic body 1 when the telescopic body 1 is contracted by an external force.

[0065] In this way, the cylinder device C can slow down either the extension or contraction operation, and not only can the operating speed be polarized depending on the direction of operation, but it can also suppress an increase in the number of parts and costs, making the valve V ideal for application to cylinder devices C that require the operating speed to be polarized.

[0066] Furthermore, the telescopic body 1 in the cylinder device C of this embodiment is spanned between the body B of the saddle-riding type vehicle M and a swing arm S that is swingable relative to the body B of the saddle-riding type vehicle M and holds the wheel W. The cylinder device C configured in this manner can adjust the vehicle height of the rear wheel side of the saddle-riding type vehicle M by opening and closing the valve V.

[0067] Furthermore, in the cylinder device C of this embodiment, the compression-side chamber R2 is open to the atmosphere and the extension-side chamber R1 is filled with liquid, and the valve V is installed in the communication passage 16 with the valve element 21 facing the extension-side chamber R1 and the valve seat member 20 facing the liquid chamber L, and the valve V provides resistance to the flow of liquid through the restricting flow path Pr when the telescopic body 1 is extended, and is fully opened when the telescopic body 1 is retracted. According to the cylinder device C configured in this manner, by opening the valve V, when the vehicle height of the rear wheel side is lowered during acceleration of the saddle-ride type vehicle M, the valve V provides resistance to the flow of liquid by the valve V, thereby reducing the rate at which the vehicle height is lowered and improving handling stability. Furthermore, when the vehicle height is raised during braking, the valve V does not provide resistance to the flow of liquid, and the telescopic body 1 quickly retracts, thereby quickly raising the vehicle height and improving vehicle stability during braking.

[0068] In addition, the valve V can be used as a valve for various hydraulic circuits other than the aforementioned cylinder device C, and the cylinder device C may also be used for a cylinder device other than one used for adjusting the vehicle height of the saddle-ride type vehicle M.

[0069] Although the preferred embodiment of the present invention has been described in detail, modifications, variations and changes can be made thereto without departing from the scope of the appended claims.

[0070] 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... Aligning member, B... Vehicle body, C... Cylinder device, G... Air chamber, L... Fluid chamber, M... Saddle-ride type vehicle, P... Link plate, Pr... Restricted flow path, R1... Extension side chamber, R2... Compression side chamber, S... Swing arm, V, V1, V2... Valve, W... Wheel

Claims

1. A valve comprising: a cylindrical valve seat member having an annular valve seat at one axial end; a valve disc having an annular seat portion which can be seated on and removed from said valve seat; a biasing member which biases the valve disc towards the valve seat member; and a restricting flow path which is formed when the valve disc is inserted into the valve seat member, wherein, when the seat portion moves away from the valve seat to open, the entire valve disc comes out of the valve seat member and fully opens against a flow from the valve seat member side to the valve disc side, and resistance is provided to a flow from the valve disc side to the valve seat member side by the restricting flow path with at least a part of the valve disc inserted into the valve seat member.

2. A valve as claimed in claim 1, wherein the valve body has a head which is movable in and out of the valve seat member, and the restricted flow passage is 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.

3. A valve as claimed in claim 2, comprising an aligning member for aligning said valve body with said valve seat member while allowing said valve body to move in the axial direction.

4. A cylinder device comprising: a cylinder; a piston movably inserted into the cylinder and dividing the interior of the cylinder into an extension-side chamber and a compression-side chamber; and a rod movably inserted into the cylinder and connected to the piston, an expandable body in which one of the extension-side chamber and the compression-side chamber is open to the atmosphere and the other of the extension-side chamber and the compression-side chamber is filled with liquid; a tank the interior of which is divided into an air chamber and a liquid chamber; a communication passage connecting the liquid chamber to the other of the extension-side chamber and the compression-side chamber; and a valve according to any one of claims 1 to 3 provided in the communication passage.

5. A cylinder device according to claim 4, wherein the telescopic body is spanned between a body of a saddle-ride type vehicle and a swing arm that is swingable relative to the body of the saddle-ride type vehicle and holds the rear wheel.

6. A cylinder device as described in claim 5, wherein the compression side chamber is open to the atmosphere and the extension side chamber is filled with liquid, and the valve is installed in the communication passage with the valve body facing the extension side chamber and the valve seat member facing the liquid chamber, so that the restricting flow path provides resistance to the flow of liquid when the telescopic body is extended, and is fully open when the telescopic body is contracted.

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