Valve device and shock absorber provided with this valve device

Abstract

A valve device (30) includes a cylindrical passage forming member (40) and a cylindrical spool valve (60) that is slidable with respect to the passage forming member (40). The passage forming member (40) has a communication port (56) that provides communication between the inside and the outside in the radial direction. The spool valve (60) has cutout parts (62, 63) that are cut out on one end surface (61) in the axial direction (Rs). The spool valve (60) can adjust the degree of communication of the cutout parts (62, 63) with respect to the communication port (56) through the relative displacement with respect to the passage forming member (40).

Description

Valve device and shock absorber equipped with this valve device

[0001] The present invention relates to a valve device and a shock absorber equipped with the valve device.

[0002] Some valve devices adjust their opening degree by electronic control. For example, by incorporating such a valve device into a shock absorber mounted on a saddle-type vehicle such as a motorcycle or tricycle, it is possible to automatically adjust the damping force of the shock absorber while the saddle-type vehicle is traveling. As a result, the valve device can automatically adjust the damping force in real time according to the traveling conditions of the saddle-type vehicle. Such a valve device and shock absorber are known, for example, from Patent Document 1.

[0003] The valve device known from Patent Document 1 includes a housing having an axially elongated hollow portion, a cylindrical spool valve slidably fitted in the hollow portion in the axial direction, and a solenoid for axially driving the spool valve. The housing has a port that radially communicates the inside and outside of the hollow portion. The spool valve has a long hole in the axial direction of the spool valve. The hole penetrates the spool valve in the radial direction and is closed at both longitudinal (axial) ends. One longitudinal end of the hole has a narrow portion with a narrow groove width. The spool valve is driven by the solenoid to adjust the degree of communication between the port and the long hole. This valve device is incorporated into a shock absorber.

[0004] Patent No. 6023446

[0005] In the valve device disclosed in Patent Document 1, the elongated hole in the spool valve has a complex shape, with one end of the groove having a different shape than the other portions in order to adjust the degree of communication with the port. To optimize the variable characteristics of the valve device, the shape of the elongated hole, particularly the narrow portion, must be machined with high precision. Furthermore, both ends of the elongated hole are closed. To machine such a complex-shaped elongated hole, typically, a hole is first drilled from the radially outer side of the spool valve using a cutting tool such as a drill, and then the cutting tool is moved from there to machine the hole into the desired shape. This makes machining the elongated hole quite difficult.

[0006] An object of the present invention is to provide a technique that can improve the processability of a spool valve while improving the variable characteristics of a valve device.

[0007] After extensive research, the inventors discovered that ensuring the variable characteristics of a valve device does not necessarily require a long hole with both ends closed. They also discovered that if there is an opening that penetrates the spool valve in the radial direction, the degree of communication of the opening with the communication port can be adjusted. The present invention was completed based on this discovery.

[0008] According to the present disclosure, there is provided a valve device including: a passage forming member formed of a cylindrical member and having a communication port that radially communicates the inside with the outside; and a spool valve formed of a cylindrical member that can slide directly or indirectly relative to the passage forming member, having at least one notch portion cut out in one end face in the axial direction, and capable of adjusting the degree of communication of the notch portion with the communication port by relative displacement with respect to the passage forming member.

[0009] The present disclosure can improve the processability of the spool valve while improving the variable characteristics of the valve device.

[0010] 1 is a side view showing a cross section of a main portion of a shock absorber equipped with a valve device according to a first embodiment. FIG. 2 is an enlarged view of the valve device and its periphery shown in FIG. 1. FIG. 3 is an exploded view of the valve device shown in FIG. 2. FIG. 4A is a perspective view of the spool valve shown in FIG. 3, and FIG. 4B is a developed view of the outer peripheral surface of the spool valve shown in FIG. 4A. FIG. 5A is a first modified view of the cutout portion shown in FIG. 4A, FIG. 5B is a second modified view of the cutout portion shown in FIG. 4A, and FIG. 5C is a third modified view of the cutout portion shown in FIG. 4A. FIG. 6 is an operation diagram of the valve device shown in FIG. 2. FIG. 7A is a schematic view showing the communication state of the cutout portion with the annular groove and communication port shown in FIG. 6, and FIG. 7B is a developed view showing the communication state of the cutout portion with the annular groove and communication port shown in FIG. 7A. FIG. 8 is a cross-sectional view of a shock absorber and a valve device according to a second embodiment. FIG. 9 is an exploded view of the spool valve and collar shown in FIG. 10.

[0011] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the embodiment shown in the accompanying drawings is an example of the present invention, and the present invention is not limited to this embodiment. In the description, "up" and "down" refer to the state in which the shock absorber is mounted on a saddle-ride type vehicle. In addition, "Up" in the drawings refers to the top, and "Dn" refers to the bottom.

[0012] First Embodiment A valve device 30 according to a first embodiment and a shock absorber 10 including the valve device 30 will be described with reference to FIGS.

[0013] 1, the shock absorber 10 is used in a motorcycle, which is a type of saddle-ride vehicle (not shown) on which a rider straddles. Hereinafter, a motorcycle may be referred to as a "saddle-ride vehicle."

[0014] The shock absorber 10 is used as a rear cushion of a saddle-ride type vehicle, for example. However, the shock absorber 10 is not limited to a rear cushion, and can also be used in a front fork.

[0015] This shock absorber 10 includes a cylindrical vehicle-side tube 11 (first tube 11) connected to a vehicle-side bracket (not shown), and a cylindrical axle-side tube 12 (second tube 12) connected to an axle-side bracket (not shown). The axle-side tube 12 is fitted into the vehicle-side tube 11 so as to be movable relative to the vehicle-side tube 11. The axle-side tube 12 also serves as a cylinder 13. The cylinder 13 may be formed as a separate member from the axle-side tube 12. In that case, the cylinder 13 only needs to extend from the lower end of the axle-side tube 12 into the interior of the axle-side tube 12. The interior of the cylindrical cylinder 13 is filled with liquid (hydraulic oil). The vehicle-side tube 11 and the axle-side tube 12 are biased by a compression coil spring 14 in directions separating them from each other.

[0016] In the first embodiment, the shock absorber 10 is described as having an inverted configuration in which the axle-side tube 12 moves forward and backward relative to the vehicle-body-side tube 11. However, the shock absorber 10 also includes an upright configuration in which the vehicle-body-side tube 11 moves forward and backward relative to the axle-side tube 12.

[0017] The shock absorber 10 further includes a piston rod 21 that extends from the upper end 11a of the vehicle body side tube 11 into the inside of the cylinder 13. A piston 22 is provided at the lower end of the piston rod 21. This piston 22 divides the inside of the cylinder 13 into two fluid chambers 23, 24 (an upper first fluid chamber 23 and a lower second fluid chamber 24). The vehicle body side tube 11, the axle side tube 12 (cylinder 13), the piston rod 21, and the piston 22 are all located on the center line CL of the piston rod 21.

[0018] The piston rod 21 is composed of a first piston rod 25 extending from the upper end 11a of the vehicle body tube 11 into the first fluid chamber 23, and a second piston rod 26 extending from the lower end 25a of the first piston rod 25 into the second fluid chamber 24. The first piston rod 25 is a cylindrical member, a so-called hollow rod. The second piston rod 26 is also called a rod end because it is located at the end of the piston rod 21. The first piston rod 25 and the second piston rod 26 are strength members that constitute the shock absorber 10, and are therefore made of a relatively high-strength material, such as steel. The piston 22 is provided in the second piston rod 26 of the piston rod 21.

[0019] A valve device 30 is incorporated into the shock absorber 10. This valve device 30 is provided in a communication passage 27, for example, in the second piston rod 26, which connects the first fluid chamber 23 and the second fluid chamber 24. By incorporating the valve device 30 into the shock absorber 10, it is possible to automatically adjust the damping force of the shock absorber 10 while the saddle-ride type vehicle is traveling. As a result, real-time damping adjustment according to the traveling conditions of the saddle-ride type vehicle can be automatically controlled by the valve device 30.

[0020] 2 and 3, the valve device 30 includes a cylindrical passage-forming member 40, a cylindrical spool valve 60 that is slidable relative to the passage-forming member 40, and a drive mechanism 70 (see also FIG. 1) that drives the spool valve 60.

[0021] The passage forming member 40 and the spool valve 60, each of which is cylindrical, are located on the center line CL of the piston rod 21. The center line CL of the piston rod 21 may be referred to as the "center line CL (axial line CL) of the passage forming member 40" or the "center line CL (axial line CL) of the spool valve 60" as appropriate. Here, the axial direction Rs of the passage forming member 40 is the direction along the center line CL of this passage forming member 40, and is the same as the axial direction Rs of the spool valve 60 (the direction along the center line CL of the spool valve 60).

[0022] The second piston rod 26 (rod end 26) also serves as the passage forming member 40 (valve body 40). This allows the valve device 30 to be easily incorporated into the piston rod 21, thereby simplifying the configuration of the valve device 30, making it more compact and reducing the number of parts. Note that the passage forming member 40 may be configured as a separate member from the piston rod 21.

[0023] The interior of this cylindrical passage forming member 40 is divided into two chambers 42, 43 (an upper first chamber 42 and a lower second chamber 43) by a partition plate 41 formed midway in the longitudinal direction (axial direction Rs). The first chamber 42 communicates with the interior of the first piston rod 25. The second chamber 43 communicates with the second fluid chamber 24.

[0024] The first end 51 of the passage forming member 40 on the first chamber 42 side has a female thread 52 that can be threadably coupled to the lower end 25a of the first piston rod 25, and a through hole 53 that penetrates radially inward and outward at the position of the first chamber 42. This through hole 53 communicates with the first chamber 42.

[0025] A second end 55 of the passage forming member 40 on the second chamber 43 side has at least one communication port 56 penetrating radially inward and outward near the partition plate 41. This communication port 56 is formed, for example, by a circular through-hole, and connects the second chamber 43 to the outside of the passage forming member 40. Furthermore, the outer peripheral surface 40a of the passage forming member 40 has an annular groove 57 (annular groove 57) formed around the entire circumference at the position of the communication port 56. The communication passage 27 connecting the first liquid chamber 23 and the second liquid chamber 24 (see FIG. 1 ) is a flow path constituted by the second chamber 43, the communication port 56, and the annular groove 57.

[0026] The annular groove 57 is formed to allow communication between the communication port 56 and the cutout portions 62, 63 (described later) of the spool valve 60 even when the spool valve 60 rotates circumferentially relative to the passage forming member 40, and can be omitted if the spool valve 60 is configured not to rotate circumferentially relative to the passage forming member 40.

[0027] 2, 3, and 4A, the spool valve 60 (valve body 60) is slidably fitted (particularly slidably in the axial direction Rs) onto the outer peripheral surface 40a of the passage forming member 40. The gap between the outer peripheral surface 40a of the passage forming member 40 and the inner peripheral surface 60a of the spool valve 60 is preferably set to the minimum possible range of relative sliding.

[0028] The spool valve 60 has at least one (preferably multiple) notches 62, 63 cut out in one end face 61 (first end face 61) in the axial direction Rs, for example, the end face 61 on the side of the first piston rod 25. In other words, open ends 62a, 63a of the notches 62, 63 coincide with the first end face 61 of the spool valve 60, and bottoms 62b, 63b of the notches 62, 63 face the other end face 64 (second end face 64) in the axial direction Rs of the spool valve 60. The notches 62, 63 penetrate the cylindrical spool valve 60 from the inside to the outside in the radial direction.

[0029] As shown in Figures 4A and 4B, it is preferable that the multiple cutout portions 62, 63 include at least one (e.g., multiple) first cutout portions 62 having a first shape and at least one (e.g., multiple) second cutout portions 63 having a second shape different from the first shape.

[0030] When viewing the spool valve 60 from the outer peripheral surface 60b side, the first shape of the first cutout portion 62 is, for example, a V-shape having an open end 62a at the first end surface 61 of the spool valve 60 and tapering toward the second end surface 64. The tip 62b (bottom 62b) of the V-shape faces the second end surface 64. The second shape of the second cutout portion 63 is, for example, a rectangular shape having an open end 63a at the first end surface 61 of the spool valve 60 and a flat bottom 63b facing the second end surface 64. For example, the bottom 62b of the V-shaped first cutout portion 62 is set deeper by a depth Dp toward the second end surface 64 than the bottom 63b of the rectangular second cutout portion 63.

[0031] The first cutout portions 62 and the second cutout portions 63 are preferably arranged alternately at equal intervals in the circumferential direction Rf of the spool valve 60. More preferably, there are pairs of first cutout portions 62 and second cutout portions 63. The pair of first cutout portions 62, 62 are arranged axially symmetrically (line-symmetrically) with respect to the center line CL of the spool valve 60. The pair of second cutout portions 63, 63 are arranged axially symmetrically (line-symmetrically) with respect to the center line CL of the spool valve 60. For example, as shown in FIG. 4B , with respect to the center line CL of the spool valve 60 as a reference, the first cutout portions 62 are located at azimuths of 0° and 180°, and the second cutout portions 63 are located at azimuths of 90° and 270°.

[0032] The shape of these cutout portions 62, 63 is arbitrary, and may be, for example, an arc shape having semicircular bottoms 62c, 63c as shown in FIG. 5A, a rectangular shape having tapered surfaces 62d, 63d as shown in FIG. 5B, or a shape having narrow auxiliary cutout portions 62f, 63f cut further from the flat bottoms 62e, 63e toward the second end face 64 as shown in FIG. 5C.

[0033] As shown in Figures 1 and 2, the drive mechanism 70 includes a drive unit 71, a rod 72 that is driven by the drive unit 71 to move in the axial direction of the spool valve 60, an arm 73 that extends from the rod 72 radially outward of the rod 72, and a pressing member 80 that is pushed by the arm 73 to move in the axial direction of the spool valve 60.

[0034] The drive unit 71 is a drive source such as a solenoid or a step motor, and is driven by a control signal from a control unit (not shown). The rod 72 is disposed within the first piston rod 25 and is movable in the axial direction Rs of the spool valve 60. The rod 72 is positioned on the center line CL of the spool valve 60, i.e., inside the cylindrical passage forming member 40. The arm 73 is fitted onto one end 72a (lower end 72a) of the rod 72 and extends radially outward beyond the passage forming member 40. The arm 73 is formed of, for example, a bar- or plate-shaped member.

[0035] The pressing member 80 is an annular member capable of pressing the first end surface 61 of the spool valve 60 in the axial direction Rs. The pressing member 80 covers the first end surface 61 of the spool valve 60 in the axial direction Rs and the open ends 62a, 63a of the cutout portions 62, 63, and can therefore be called a lid member. More specifically, as shown in FIGS. 2 and 3 , the pressing member 80 has an inner circumferential surface 80a that can be fitted onto the outer circumferential surface 60b of the spool valve 60, and an annular flange 81 having a smaller diameter than the inner circumferential surface 80a. The flange 81 has an upper first flange surface 81a that can be pressed by the arm 73, and a lower second flange surface 81b that can be pressed against the first end surface 61 of the spool valve 60. The first and second flange surfaces 81a, 81b are flat surfaces that are parallel to each other and perpendicular to the center line CL of the spool valve 60. The drive portion 71 can move the spool valve 60 in the axial direction Rs via the arm 73 and the pressing member 80 .

[0036] The drive mechanism 70 further includes a biasing member 90 that biases the spool valve 60 toward the pressing member 80. The biasing member 90 is, for example, a compression coil spring. The biasing member 90 may be referred to as the "compression coil spring 90" as appropriate. The compression coil spring 90 is interposed between the spring bearing portion 58 provided on the passage forming member 40 and the spring bearing portion 65 provided on the outer peripheral surface 60b of the spool valve 60, thereby biasing the spool valve 60 in a direction that closes the communication port 56 of the passage forming member 40 (upward in the axial direction Rs). As a result, the compression coil spring 90 maintains the communication port 56 of the spool valve 60 in a fully closed state (see FIG. 2 ) and maintains the first end surface 61 of the spool valve 60 pressed against the pressing member 80. The inner peripheral surface 60a of the spool valve 60 closes the communication port 56 and the annular groove 57.

[0037] Next, the operation of the valve device 30 configured as described above will be described. As shown in Figure 2, when the drive unit 71 (see Figure 1) is not pushing the rod 72 toward the passage forming member 40, the compression coil spring 90 holds the communication port 56 and the annular groove 57 of the spool valve 60 in a fully closed state. In this fully closed state, the first end surface 61 of the spool valve 60 is pressed against the pressing member 80.

[0038] 6, the drive unit 71 (see FIG. 1) pushes the rod 72 toward the passage forming member 40 against the biasing force of the compression coil spring 90, causing the arm 73 to press the first flange surface 81a of the pressing member 80 toward the spool valve 60 by the pushing stroke (movement amount). Therefore, the pressing member 80 presses the first end surface 61 of the spool valve 60 toward the compression coil spring 90 with the second flange surface 81b. The spool valve 60 displaces downward Dn in the axial direction Rs against the biasing force of the compression coil spring 90, thereby opening the annular groove 57 in accordance with the displacement amount. As a result, the degree of communication between the cutout portions 62, 63 and the communication port 56 can be adjusted.

[0039] The degree of communication of the cutout portions 62, 63 with the communication port 56 will be described in more detail. Fig. 7A schematically shows the communication state of the cutout portions 62, 63 with the annular groove 57 and communication port 56 shown in Fig. 6. Fig. 7B shows an expanded view of the communication state of the cutout portions 62, 63 with the annular groove 57 and communication port 56 shown in Fig. 7A.

[0040] When the spool valve 60 is opened to a desired position, the opening area of ​​the V-shaped first notch 62 relative to the annular groove 57 is A1, and the opening area of ​​the rectangular second notch 63 relative to the annular groove 57 is A2. Since there are pairs of first notch 62 and second notch 63, the total opening area A10 (not shown) can be calculated using the formula A10 = 2 × (A1 + A2). Thus, the total opening area A10 changes according to the displacement (stroke) of the spool valve 60 in the axial direction Rs. The variable opening area characteristic relative to the stroke can be set arbitrarily by appropriately designing the shapes of the bottoms 62b, 63b of the notches 62, 63. Therefore, by combining the shape, size, arrangement, and number of the notches 62, 63, the degree of communication of the notches 62, 63 relative to the communication port 56 can be optimized depending on the application of the valve device 30.

[0041] The present invention is used in a shock absorber 10, and the damping force characteristics of the shock absorber 10 can be easily controlled by making them as consistent as possible with respect to the stroke of the spool valve 60. This can be achieved by combining arc-shaped or triangular shapes for the bottoms 62b, 63b of the notches 62, 63 of the spool valve 60 of the valve device 30, and then adding up the changes in the opening area. Machining "holes" in arc-shaped, triangular, or rectangular shapes is extremely difficult. From a setting perspective, creating different variations in hole machining can be difficult, but by machining notches (grooves) from the open ends 62a, 63a, any desired shape can be easily achieved.

[0042] As is clear from the above description, the spool valve 60 can adjust the degree of communication between the notches 62 and 63 and the communication port 56 by displacing the spool valve 60 relative to the passage forming member 40 in the axial direction Rs.

[0043] Second Embodiment A valve device 130 according to a second embodiment and a shock absorber 100 including the valve device 130 will be described with reference to FIGS. 8 and 9. FIG.

[0044] Figure 8 is a cross-sectional view illustrating the shock absorber 100 and the valve device 130, and corresponds to Figure 2. Figure 9 is an exploded view of the main components of the valve device 130, and corresponds to Figure 3. The valve device 130 of the second embodiment is characterized by adding a collar 140 shown in Figures 8 and 9 to the valve device 30 of the first embodiment shown in Figures 1 to 7. The other basic configuration is common to the valve device 30 of the first embodiment and the shock absorber 10 equipped with this valve device 30. The same reference numerals will be used for parts common to the valve device 30 and shock absorber 10 of the first embodiment, and detailed description thereof will be omitted.

[0045] More specifically, in the valve device 130 of the second embodiment, a cylindrical collar 140 is interposed between the outer peripheral surface 40a of the passage forming member 40 and the inner peripheral surface 60a of the spool valve 60. The collar 140 is fitted to the outer peripheral surface 40a of the passage forming member 40 while being restricted from moving relative to the outer peripheral surface 40a in the axial direction Rs. The spool valve 60 is slidably fitted to the outer peripheral surface 140a of the collar 140, thereby being configured to be indirectly slidable relative to the passage forming member 40. In order to prevent fluid leakage from the fitted portion between the passage forming member 40 and the collar 140 as much as possible, it is preferable to improve the sealing performance between the two (e.g., by improving the fitting precision).

[0046] The collar 140 has at least one communication port 141 penetrating radially from the inside to the outside. Furthermore, an annular groove 142 (annular groove 142) is formed around the entire circumference of the outer circumferential surface 140a of the collar 140 at the position of the communication port 141. In the second embodiment, the communication passage 127 connecting the first liquid chamber 23 and the second liquid chamber 24 (see FIG. 1) is a flow path formed by the second chamber 43, the communication port 56, the annular groove 57, and the communication port 141 and annular groove 142 of the collar 140.

[0047] The annular grooves 57, 142 are formed to allow communication between the communication port 56 and the cutout portions 62, 63 even when the spool valve 60 rotates circumferentially relative to the passage forming member 40, and can be omitted if the spool valve 60 is configured not to rotate circumferentially relative to the passage forming member 40.

[0048] The linear expansion coefficient of the collar 140 is greater than the linear expansion coefficients of the passage forming member 40 and the spool valve 60. For example, the passage forming member 40 and the spool valve 60 are made of steel, and the collar 140 is made of aluminum (including aluminum alloys). The spool valve 60 slides on the outer peripheral surface 140a of the aluminum collar 140, so it is preferable that the outer peripheral surface 140a be coated with a highly wear-resistant coating (for example, an anodized coating) to enhance wear resistance.

[0049] When the ambient temperature in which the shock absorber 100 is used rises, thermal expansion occurs in the passage forming member 40, the spool valve 60, and the collar 140. The diameter d1 of the inner circumferential surface 60a of the spool valve 60 and the diameter d2 of the outer circumferential surface 140a of the collar 140 shown in Fig. 9 are set within a range that allows sliding of the inner circumferential surface 60a of the spool valve 60 relative to the outer circumferential surface 140a of the collar 140, taking into consideration the difference in thermal expansion when the ambient temperature is within a preset reference temperature.

[0050] The functions and effects of the valve device 130 of the second embodiment and the shock absorber 100 equipped with this valve device 130 are the same as the functions and effects of the valve device 30 of the first embodiment and the shock absorber 10 equipped with this valve device 30.

[0051] The above-described valve devices 30, 130 and the shock absorbers 10, 100 equipped with these valve devices 30, 130 can be summarized as follows.

[0052] 2 and 8. According to the first and second embodiments, firstly, the valve device 30, 130 includes a passage forming member 40 that is made of a cylindrical member and has a communication port 56 that radially communicates the inside with the outside, and a spool valve 60 that is made of a cylindrical member that can slide directly or indirectly relative to the passage forming member 40, has at least one notch portion 62, 63 cut out in one end face 61 (first end face 61) in the axial direction Rs, and is capable of adjusting the degree of communication of the notch portion 62, 63 with the communication port 56 by relative displacement with respect to the passage forming member 40.

[0053] As described above, the passage forming member 40 has a communication port 56 that communicates radially. The cylindrical spool valve 60 has cutouts 62, 63 on one end surface 61 in the axial direction Rs. The degree of communication between the cutouts 62, 63 and the communication port 56 can be easily adjusted by relative displacement of the spool valve 60 with respect to the passage forming member 40. Furthermore, the cylindrical spool valve 60 has the cutouts 62, 63 on one end surface 61. The cutouts 62, 63 can be easily formed by setting parameters for the size of the cutouts 62, 63, their depth in the axial direction Rs, and their shape, and then machining the cutouts 62, 63 from the one end surface 61 in the axial direction Rs. Shape parameters include, for example, a V-shape or a rectangular shape, and the shape of the bottoms 62b, 63b. This improves the variable characteristics of the valve device 30 while also improving the workability of the spool valve 60.

[0054] See Figures 2, 4A, 4B, and 8. Secondly, preferably, in the valve device 30, 130 described above, the cutout portions 62, 63 include at least one first cutout portion 62 having a first shape and at least one second cutout portion 63 having a second shape different from the first shape. The first cutout portion 62 and the second cutout portion 63 are arranged in the circumferential direction Rf of the spool valve 60. In this manner, the first cutout portion 62 having the first shape and the second cutout portion 63 having the second shape have different opening characteristics. By arranging the cutout portions 62, 63 having different shapes in the circumferential direction Rf of the spool valve 60, a variety of variable characteristics of the valve device 30 can be obtained.

[0055] See Figures 2, 4A, 4B, and 8. Third, preferably, in the valve device 30, 130 described in the second aspect, the first cutout portions 62 and the second cutout portions 63 are each provided in pairs. The pair of first cutout portions 62, 62 are arranged symmetrically (line-symmetrically) about the axis of the spool valve 60. The pair of second cutout portions 63, 63 are arranged symmetrically about the axis of the spool valve 60. In this way, by arranging cutout portions of the same shape symmetrically about the axis of the spool valve 60, i.e., the pair of first cutout portions 62, 62 or the pair of second cutout portions 63, 63, it is possible to balance the opening characteristics. As a result, the hydraulic balance of the valve device 30, 130 can be appropriately set.

[0056] See Figures 1, 2, and 8. Fourth, preferably, the valve device 30, 130 according to any one of the first to third embodiments further includes a pressing member 80 capable of pressing one end surface 61 (first end surface 61) of the spool valve 60 in the axial direction Rs, and a drive unit 71 that moves the spool valve 60 in the axial direction Rs via the pressing member 80. That is, the open ends 62a, 63a of the cutout portions 62, 63 are located on the one end surface 61 of the spool valve 60 in the axial direction Rs. The pressing member 80 is interposed between the one end surface 61 and the drive unit 71. Therefore, despite the presence of the open ends 62a, 63a of the cutout portions 62, 63 on the one end surface 61, the drive force of the drive unit 71 can be reliably transmitted to the spool valve 60.

[0057] See Figures 2 and 8. Fifth, preferably, in the valve devices 30, 130 described in any of the first to fourth aspects, the spool valve 60 is slidably fitted onto the outer peripheral surface 40a of the passage forming member 40. In other words, the spool valve 60 surrounds the outer peripheral surface 40a of the passage forming member 40. Compared to a configuration in which the spool valve 60 is combined inside the passage forming member 40, the valve devices 30, 130 can be made smaller.

[0058] 2 and 8. Sixth, preferably, the valve device 30, 130 according to the fifth aspect includes a rod 72 that is positioned inside the passage forming member 40 and is movable in the axial direction Rs of the spool valve 60, and an arm 73 that extends radially outward from the rod 72 and moves together with the rod 72 to drive the spool valve 60 in the axial direction Rs. Therefore, the rod 72 that is positioned inside the passage forming member 40 can drive the spool valve 60 that is positioned outside the passage forming member 40 in the axial direction Rs via the arm 73. Even though the spool valve 60 is positioned outside the passage forming member 40, it can be easily driven by the rod 72 that is positioned on the central side.

[0059] See Fig. 8. Seventh, preferably, the valve device 130 according to any one of the first to sixth aspects includes a cylindrical collar 140 interposed between the outer peripheral surface 40a of the passage forming member 40 and the inner peripheral surface 60a of the spool valve 60. The spool valve 60 is configured to be slidably fitted onto the outer peripheral surface 140a of the collar 140, thereby being indirectly slidable relative to the passage forming member 40. The linear expansion coefficient of the collar 140 is greater than the linear expansion coefficient of the spool valve 60.

[0060] As the environmental temperature in which the valve device 130 is used increases, the spool valve 60 and the collar 140 thermally expand. Because the linear expansion coefficient of the collar 140 is greater than that of the spool valve 60, the gap between the inner circumferential surface 60a of the spool valve 60 and the outer circumferential surface 140a of the collar 140 decreases as the temperature increases. This reduction in the gap reduces hydraulic fluid leakage from this gap. Because the higher the temperature, the less hydraulic fluid leakage there is, the more precisely the degree of communication between the notches 62, 63 and the communication port 56 can be adjusted. In other words, the temperature characteristics of the valve device 130 can be improved. For example, in a shock absorber 100 equipped with the valve device 130, the rate at which the damping force changes with temperature (the temperature characteristics of the damping force) can be reduced, thereby achieving stable damping force characteristics regardless of the material of the passage-forming member 40.

[0061] See Figures 1, 2 and 8. Eighth, the shock absorber 10, 100 preferably includes a cylinder 13, a piston 22 that divides the interior of the cylinder 13 into a first fluid chamber 23 and a second fluid chamber 24, and the valve device 30, 130 described in any of the first to seventh aspects that is provided in a communication passage 27, 127 that communicates between the first fluid chamber 23 and the second fluid chamber 24. Therefore, by incorporating the valve device 30, 130, the shock absorber 10, 100 can exert a stable damping force.

[0062] The valve device 30, 130 according to the present invention and the shock absorber 10, 100 equipped with this valve device 30, 130 are not limited to the above-described embodiment, as long as they exhibit the functions and effects of the present invention.

[0063] The valve device 30, 130 of the present invention and the shock absorber 10, 100 equipped with this valve device 30, 130 are suitable for application to front forks and rear dampers mounted on saddle-ride type vehicles.

[0064] DESCRIPTION OF SYMBOLS 10... Shock absorber, 13... Cylinder, 21... Piston rod, 22... Piston, 23... First fluid chamber, 24... Second fluid chamber, 27... Communicating passage, 30... Valve device, 40... Passage forming member, 40a... Outer peripheral surface, 56... Communicating port, 60... Spool valve, 60a... Inner peripheral surface, 60b... Outer peripheral surface, 61... First end surface (one end surface), 62... Notched portion (first notched portion), 62a... Opening end, 63... Notched portion (second notched portion), 63a... Opening end, 64... Second end surface (other end surface), 71... Drive portion, 72... Rod, 72a... One end (lower end portion), 73... Arm, 80... Pressing member, 80a... Inner peripheral surface, 100... Shock absorber, 127... Communicating passage, 130... Valve device, 140... Collar, 140a... Outer circumferential surface, 141... Communication port, Rf... Circumferential direction of spool valve, Rs... Axial direction of passage forming member (spool valve).

Claims

1. A valve device comprising: a passage forming member formed of a cylindrical member and having a communication port that radially communicates between the inside and the outside; and a spool valve formed of a cylindrical member that can slide directly or indirectly against said passage forming member, having at least one notch cut into one end face in the axial direction, and capable of adjusting the degree of communication of the notch with the communication port by relative displacement with respect to said passage forming member.

2. The valve device according to claim 1, wherein the cutout portion includes at least one first cutout portion having a first shape and at least one second cutout portion having a second shape different from the first shape, and the first cutout portion and the second cutout portion are arranged in the circumferential direction of the spool valve.

3. The valve device according to claim 2, wherein the first cutout portions and the second cutout portions each have a pair, the pair of first cutout portions are arranged symmetrically about the axis of the spool valve, and the pair of second cutout portions are arranged symmetrically about the axis of the spool valve.

4. The valve device according to claim 1, further comprising: a pressing member capable of pressing said one axial end face of said spool valve; and a drive unit that moves said spool valve in the axial direction via said pressing member.

5. The valve device according to claim 1, wherein said spool valve is slidably fitted onto the outer circumferential surface of said passage forming member.

6. The valve device according to claim 1, further comprising: a rod located inside said passage forming member and movable in the axial direction of said spool valve; and an arm extending radially outward from said rod and moving together with said rod to drive said spool valve in the axial direction.

7. The valve device as described in claim 1, further comprising a cylindrical collar interposed between an outer peripheral surface of the passage forming member and an inner peripheral surface of the spool valve, the spool valve being configured to be indirectly slidable relative to the passage forming member by being slidably fitted onto the outer peripheral surface of the collar, and the linear expansion coefficient of the collar being greater than the linear expansion coefficient of the passage forming member.

8. A shock absorber comprising: a cylinder; a piston that divides the inside of the cylinder into a first liquid chamber and a second liquid chamber; and a valve device as described in claim 1 that is provided in a communication passage that communicates between the first liquid chamber and the second liquid chamber.

Images