Switching valve and hydraulic shock absorber including switching valve

Abstract

A switching valve (10) comprises a valve seat (54), a valve body (60), a passage portion (73), and a regulating portion (71a). The valve seat (54) has a valve seat face (54b) formed along the circumference of a valve opening (54a). The valve body (60) is a resin molded product which moves in a direction along the axis line (CL) of the valve seat face (54b). The valve body (60) has a sealing portion (61) which has a curved sealing face (61a) that is capable of sealing the valve seat face (54b) and an extending portion (62) which extends from the sealing portion (61) in the direction away from the sealing face (61a) and in which a trace portion (63) generated during resin molding remains as it is. The passage portion (73) has an oil passage (73a) which forms part of a flow path (Fp) when the sealing face (61a) moves away from the valve seat face (54b). The regulating portion (71a) regulates the posture of the extending portion (62) so as to maintain the open / close position of the sealing face (61a) relative to the valve seat face (54b).

Description

Switching valve and hydraulic shock absorber equipped with this switching valve

[0001] The present invention relates to an improved technique for a switching valve and a hydraulic shock absorber equipped with the switching valve.

[0002] Among selector valves, there is a so-called ball-type selector valve, which uses a ball-shaped (spherical) valve element that can approach and separate from a valve seat surface and move in a direction along the axis of the valve seat surface to open and close a valve port. This type of ball-type selector valve is also widely used in check valves, relief valves, and hydraulic shock absorbers, for example. This type of ball-type selector valve is known, for example, from Patent Document 1.

[0003] The ball-type switching valve known from Patent Document 1 is installed in a hydraulic shock absorber (electrically controlled damper) and includes a valve seat with a tapered valve seat surface, a ball-shaped valve element that can approach and separate from the valve seat surface, and a compression coil spring that presses the valve element against the valve seat surface. The valve element moves in a direction along the axis of the valve seat surface to open and close a valve port. The valve port is connected to a flow path through which oil flows. The biasing force of the compression coil spring is transmitted to the valve element via a pressing member. When the valve element is pushed away from the valve seat surface by a push rod, the valve port of the ball-type switching valve opens and oil flows into the flow path. The ball-shaped valve element has good sealing properties due to its high contact surface pressure with the valve seat surface.

[0004] Japanese Patent Application Laid-Open No. 2016-176552 (see FIGS. 3 and 4)

[0005] In the switching valve known from Patent Document 1, the valve disc has a ball-shaped configuration, so the entire spherical surface can serve as a sealing surface. Therefore, the area where the valve disc contacts the valve seat surface is not constant. This valve disc may be made of a resin molded product, for example, to reduce costs. When the valve disc is molded from resin, traces (molding traces) such as parting lines and discharge gates may be left behind. Regardless of the area where the valve disc contacts the valve seat surface, the traces must be polished to prevent any adverse effects on the sealing performance of the valve disc. Including a polishing process in the valve disc production process is disadvantageous in terms of increasing valve disc productivity and reducing the production cost of switching valves.

[0006] An object of the present invention is to provide a technique that can reduce costs while ensuring sealing performance of a switching valve having a valve body made of a resin molded product.

[0007] After extensive research, the inventors discovered that only the sealing surface of the valve disc that comes into contact with the valve seat surface needs to be curved. They then discovered that by making only the sealing surface of the valve disc curved and leaving the other parts uncurved, it becomes possible to regulate the position of the valve disc, and as a result, the part of the valve disc that comes into contact with the valve seat surface becomes constant. The present invention was completed based on this discovery.

[0008] According to the present disclosure, there is provided a switching valve including: a valve seat having a valve port capable of communicating with a flow path through which oil flows and a valve seat surface formed on the periphery of the valve port; a valve body having a member made of a resin-molded product that moves toward and away from the valve seat surface in a direction along the axis of the valve seat surface to open and close the valve port, the valve body having a seal portion having a curved seal surface that can come into contact with the valve seat surface to seal, and an extension portion that is formed integrally with the seal portion and extends opposite to the seal surface, and in which traces created during resin molding remain; a passage portion having an oil passage that can form part of the flow path when the seal surface of the valve body moves away from the valve seat surface; and a regulating portion that regulates the attitude of the extension portion so as to maintain the open / closed position of the seal surface relative to the valve seat surface.

[0009] The present disclosure can provide a technique that can reduce costs while ensuring sealing performance of a switching valve having a valve body made of a resin molded product.

[0010] 13A is a side view of the second valve body shown in FIG. 12, and FIG. 13B is a view of the second valve body taken along the line 13B of the arrow in FIG. 13A. FIG. 13B is an enlarged view of the first valve body, the second valve body, and the compression coil spring shown in FIG. 11. FIG. 13A is a side view of the second valve body shown in FIG. 12, and FIG. 13B is a view of the second valve body taken along the line 13B of the arrow in FIG. 13A. FIG. 13B is an enlarged view of the first valve body, the second valve body, and the compression coil spring shown in FIG. 11. FIG. 13B is a view for explaining the state in which the inclination of the second valve body with respect to the second valve seat surface shown in FIG. 14 is restricted. FIG. 13C is an operational diagram of the valve body shown in FIG. 11 in the open state.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Note that the embodiments shown in the accompanying drawings are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0012] First Embodiment A switching valve 10 according to a first embodiment and a hydraulic shock absorber 100 including the switching valve 10 will be described with reference to FIGS. 1 to 9. FIG.

[0013] As shown in Fig. 1, the switching valve 10 opens and closes a flow path Fp (see arrow Fp in Fig. 1) through which oil flows, and can be provided in various oil devices. This switching valve 10 is configured as an automatic valve, for example, in which a valve device 11 is driven by an actuator 20. However, the switching valve 10 is not limited to the configuration of an automatic valve.

[0014] First, the actuator 20 will be described. The actuator 20 is preferably configured as an electromagnetic solenoid equipped with an actuating rod 21. The actuator 20 may be referred to as the "electromagnetic solenoid 20" where appropriate. The electromagnetic solenoid 20 is configured as a proportional solenoid in which the amount of current supplied to the excitation coil 22 is proportional to the advancement distance (advance / retraction amount) of the plunger 23. Furthermore, the electromagnetic solenoid 20 advances the plunger 23 by excitation of the excitation coil 22. The actuating rod 21 can advance and retract together with the plunger 23 in a direction along the center line CL of the actuating rod 21. As such, the electromagnetic solenoid 20 is configured as a proportional solenoid, and therefore the opening degree of the valve device 11 can be adjusted according to the advancement distance of the plunger 23 and the actuating rod 21.

[0015] The excitation coil 22 and the plunger 23 are housed in a cylindrical actuator housing 24. One end of the actuator housing 24 is closed by a lid 25. The actuation rod 21 passes through the lid 25.

[0016] The valve device 11 is provided at one end of the actuator housing 24 via a booster mechanism 30. The booster mechanism 30 is located on the opposite side of the lid 25 from the electromagnetic solenoid 20. The booster mechanism 30 utilizes moment balance to obtain a large pushing force (output) from a small pushing force (input) of the operating rod 21.

[0017] The booster mechanism 30 is composed of, for example, first and second pushing members 31, 32 and an elastic plate-like member 33 interposed between these pushing members 31, 32. The first and second pushing members 31, 32 and the plate-like member 33 are arranged on the center line CL of the actuation rod 21. The pushing force of the actuation rod 21 pressing the first pushing member 31 is boosted by the plate-like member 33 and transmitted to the second pushing member 32. The second pushing member 32 is integrally provided with a pushing portion 34 at its tip (lower end). The pushing portion 34 functions as a valve rod. The booster mechanism 30 is housed in a storage portion 35 fixed to one end of the actuator housing 24. The storage portion 35 is composed of a flat-plate-shaped first support member 36 overlapping the lid 25 and a cup-shaped second support member 37 overlapping the first support member 36.

[0018] The valve device 11 is removably attached to the lower end of the booster mechanism 30. More specifically, as shown in Fig. 2, the valve device 11 has a so-called pilot changeover valve configuration, including a valve housing 40 and a first valve body 50 and a second valve body 60 housed in the valve housing 40. Hereinafter, the changeover valve 10 may be referred to as the "pilot changeover valve 10" as appropriate.

[0019] The valve housing 40 includes a flat first housing portion 41, a cylindrical second housing portion 42, and a bottomed cylindrical third housing portion 43. Any two or all of these housing portions 41 to 43 may be integrated into one body.

[0020] The first housing portion 41 can be fitted onto the lower end of the second support member 37 (see FIG. 1). A guide space 44 that guides oil flowing from the valve device 11 to the outside is formed between the first housing portion 41 and the second support member 37. As shown in FIG. 3, the first housing portion 41 has a first valve seat 41a on the center line CL of the operating rod 21. The first valve seat 41a has a first valve port 41b that can communicate with the flow path Fp (see FIG. 1) through which oil flows, and a first valve seat surface 41c formed on the periphery of the first valve port 41b.

[0021] As shown in Figure 3, the second housing part 42 can be fitted into one end face 41d of the first housing part 41 (the face 41d opposite the power boosting mechanism 30) and has a first oil inlet 42a that penetrates radially inward and outward.

[0022] As shown in FIG. 2 , the third housing portion 43 can press the second housing portion 42 against one end surface 41d of the first housing portion 41. The third housing portion 43 includes a cylindrical portion 43a that surrounds the outer peripheral surface 42b of the second housing portion 42 and a flat bottom plate 43b that is integrally formed with the bottom of the cylindrical portion 43a. The bottom plate 43b of the third housing portion 43 has at least one second oil inlet 43c (orifice 43c) that penetrates from the inside to the outside and a communication groove 43d that communicates with the second oil inlet 43c. The second oil inlet 43c is located on the center line CL of the operating rod 21. The communication groove 43d is formed in a bottom surface 43e of the bottom plate 43b and communicates with the outer peripheral surface 43f of the third housing portion 43.

[0023] 3 and 4 , the first valve body 50 can move toward and away from the first valve seating surface 41 c in a direction along the center line CL of the actuation rod 21 (the axis CL of the first valve seating surface 41 c) to open and close the first valve port 41 b. The first valve body 50 is slidably guided along the axis CL of the first valve seating surface 41 c by the inner circumferential surface 42 c of the second housing portion 42. The first valve body 50 is a bottomed, tubular member that opens toward the bottom plate 43 b of the third housing portion 43. The first valve body 50 includes a first cylindrical portion 51 that is slidably fitted onto the inner circumferential surface 42 c of the second housing portion 42, and a flat first bottom plate 52 (also referred to as a first top plate 52) that is integrally formed with the bottom of the first cylindrical portion 51.

[0024] The bottom surface 52a of the first bottom plate 52 of the first valve body 50 is a flat surface perpendicular to the center line CL of the actuation rod 21, and has an annular first seal surface 53 on its edge. This first seal surface 53 is a flat surface perpendicular to the center line CL of the actuation rod 21, and is formed flush with the bottom surface 52a, or as a convex or concave surface. The first valve body 50 is, for example, a resin molded product.

[0025] The combined structure of the first valve seat surface 41c of the first housing portion 41 and the first seal portion 52a of the first valve body 50 constitutes the first valve 12. This first valve 12 functions as the main valve of the pilot changeover valve 10 (changeover valve 10), and opens and closes by moving the first seal portion 52a toward and away from the first valve seat surface 41c. This first valve 12 may be referred to as the "main valve 12" as appropriate.

[0026] The inner bottom surface 52b (inner bottom surface 52b) of the first bottom plate 52 of the first valve body 50 is a flat surface perpendicular to the center line CL of the actuation rod 21, and is provided with a second valve seat 54 on the center line CL of the actuation rod 21. The second valve seat 54 has a second valve port 54a that can communicate with the flow path Fp through which oil flows, and a second valve seat surface 54b formed on the periphery of the second valve port 54a. The second valve port 54a is located on the center line CL of the actuation rod 21 and penetrates the first bottom plate 52. The second valve seat surface 54b is, for example, a tapered surface or an arc-shaped surface that tapers from the inner bottom surface 52b of the first bottom plate 52 to the second valve port 54a.

[0027] The first valve body 50 has a small-diameter portion 55, the diameter of which is smaller than that of the outer circumferential surface 50a, at a portion of the outer circumferential surface 50a that faces the first oil inlet 42a of the second housing portion 42. The outer circumferential surface 50a of the first valve body 50 and the outer circumferential surface 55a of the small-diameter portion 55 are continuous by a stepped surface 56. A space 57 is formed between the small-diameter portion 55 and the inner circumferential surface 42c of the second housing portion 42. This space 57 functions as an upstream hydraulic chamber with respect to the first valve 12. The hydraulic pressure acting on the stepped surface 56 is converted into a force that pushes the first valve body 50 along the center line CL in a direction away from the first valve seat 41a.

[0028] 3 and 4, the second valve body 60 is a resin molded product, preferably made of flexible resin, more preferably made of urethane resin (polyurethane) or nitrile rubber (NBR). The second valve body 60 is movable toward and away from the second valve seating surface 54b in a direction along the center line CL of the actuating rod 21 (the axis CL of the second valve seating surface 54b), thereby opening and closing the second valve port 54a.

[0029] Referring also to FIG. 5 , the second valve body 60 is an integrally molded product including a second seal portion 61 having a second seal surface 61a and an extension portion 62 extending from the second seal portion 61 toward the opposite side of the second seal surface 61a. The second seal surface 61a (sealing area 61a) is curved and can abut against the second valve seat surface 54b to provide a seal. The second seal portion 61 is configured, for example, in a hemispherical shape. The extension portion 62 is continuous with a bottom portion 61b (boundary 61b) of the second seal portion 61 and is cylindrical with a diameter Bd equal to the diameter Bd of the bottom portion 61b. The bottom surface 62a of the extension portion 62 is a flat surface perpendicular to the axis CL of the second valve seat surface 54b.

[0030] When the second valve body 60 is molded from resin, traces 63 (molding traces 63) such as parting lines and discharge gates may be generated on the second valve body 60. In the first embodiment, the portion where the traces 63 may be generated is set in advance to the extension portion 62 of the second valve body 60, which does not require sealing. The traces 63 generated when the second valve body 60 is molded from resin remain as they are on the extension portion 62 without being removed.

[0031] 3, the combined structure of the second valve seat surface 54b and the second seal portion 61 of the second valve body 60 constitutes the second valve 13. This second valve 13 has the function of the pilot valve of the pilot changeover valve 10 (changeover valve 10), and opens and closes by moving the second seal portion 61 toward and away from the second valve seat surface 54b. This second valve 13 may be referred to as the "pilot valve 13" as appropriate.

[0032] 3 and 4, the second valve 13 includes a second holding member 70 that holds the extension portion 62. The second holding member 70 is fitted into the inner circumferential surface 51a of the first cylindrical portion 51 of the first valve body 50, and is slidably held by this inner circumferential surface 51a. In other words, the second holding member 70 is held in its position by the first cylindrical portion 51, and is movable along the center line CL of the actuation rod 21 (the axis line CL of the second valve seat surface 54b). The first valve body 50 may be referred to as the "first holding member 50" as appropriate.

[0033] Furthermore, the second retaining member 70 has a concave retaining hole 71 (first recess 71) on one end surface 70a facing the inner bottom surface 52b of the first bottom plate 52 of the first valve body 50. The inner circumferential surface 71a forming this second retaining hole 71 has a circular configuration that allows the cylindrical extension portion 62 to fit within it. The bottom surface 71b of the retaining hole 71 is a flat surface perpendicular to the axis CL of the second valve seat surface 54b. The extension portion 62 is tightly fitted into the retaining hole 71 and is held therein by, for example, press-fitting. Therefore, the inner circumferential surface 71a forming the retaining hole 71 regulates the orientation of the extension portion 62 so as to maintain the open / closed position of the second seal surface 61a relative to the second valve seat surface 54b. The bottom surface 62a of the extension portion 62 preferably contacts the bottom surface 71b of the retaining hole 71. The inner peripheral surface 71a of the holding hole 71 may be referred to as a "restriction portion 71a" as appropriate. In other words, the restriction portion 71a is formed on the second holding member 70. This second holding member 70 is made of, for example, a resin molded product.

[0034] The columnar configuration of the extension 62 may include a cylindrical configuration. By configuring the extension 62 in a cylindrical shape, it is possible to make it easier to fit the extension 62 into the holding hole 71.

[0035] The combined structure of the second valve body 60 and the second holding member 70 that holds the position of the second valve body 60 constitutes a single valve body unit 81. In other words, the entire valve body unit 81 can be considered to constitute the valve body of the second valve 13.

[0036] Furthermore, the second retaining member 70 is biased toward the bottom surface 52a of the first bottom plate 52 of the first valve body 50 by a biasing member 82. This biasing member 82 is, for example, a compression coil spring. The biasing member 82 may be referred to as the "compression coil spring 82" as appropriate. This compression coil spring 82 is interposed between the bottom plate 43b of the third housing portion 43 and the second retaining member 70. For example, the second retaining member 70 has a spring receiving recess 72 (second recess 72) that receives one end 82a of the compression coil spring 82 on an end surface 70b (other end surface 70b) opposite the portion 71 (retaining hole 71) that holds the extension portion 62. The position of the one end 82a of the compression coil spring 82 relative to the second retaining member 70 is determined by fitting into the spring receiving recess 72. The bottom surface 72a of the spring receiving recess 72 is biased by a compression coil spring 82 in a direction in which the second seal surface 61a of the second valve body 60 abuts against the second valve seat surface 54b.

[0037] Referring also to FIG. 6 , the second valve 13 further includes a passage portion 73 formed in the second holding member 70. This passage portion 73 is configured to form part of a flow path Fp (see arrow Fp in FIG. 1 ) through which oil flows when the second valve 13 is opened, i.e., when the second seal surface 61a of the second valve body 60 separates from the second valve seating surface 54b. This passage portion 73 is configured by at least one (preferably multiple) oil passages 73a formed in the outer peripheral surface 70c of the second holding member 70. This oil passage 73a is, for example, configured by a groove formed in the outer peripheral surface 70b of the second holding member 70 and penetrates the second valve seating surface 54b in the direction of the axis CL. The groove-shaped oil passage 73a is blocked by the inner peripheral surface 51a of the first cylindrical portion 51 of the first valve body 50. This allows oil to pass through the oil passage 73a.

[0038] As shown in FIGS. 3 and 4 , a portion 74 of the outer circumferential surface 70c of the second retaining member 70 corresponding to the retaining hole 71 (portion 71 that retains the extension portion 62) is formed with a small diameter. A space 75 is formed radially outward of this small diameter portion 74 (small diameter portion 74). This space 75 constitutes a passage for oil flowing between the oil passage 73a and the second valve seat 54. This space 75 may be referred to as the "oil passage 75" as appropriate. In other words, the oil passage 75 between the oil passage 73a and the second valve seat 54 is formed around at least the entire periphery of the outer circumferential surface 70c of the second retaining member 70 that retains the extension portion 62.

[0039] As is clear from the above description, the second valve 13 has an elongated configuration, including a hemispherical second seal portion 61 and a cylindrical extension portion 62. Moreover, the extension portion 62 is held by the second holding member 70. Therefore, the length in the axis CL direction of the valve body unit 81 formed by the combination of the second valve body 60 and the second holding member 70 is longer than that of a conventional ball-shaped (spherical) valve body.

[0040] In contrast, the second valve body 60 and the second holding member 70 are fitted and housed inside the cylindrical first valve body 50 with a bottom. The bottom surface 52a (outer surface 52a) of the first bottom plate 52 of the first valve body 50 has the first seal portion 52a of the first valve body 50 of the first valve 12. The inner bottom surface 52b (inner bottom surface 52b) of the first bottom plate 52 of the first valve body 50 has the second valve seat 54 of the second valve 13. One of the features of the switching valve 10 is that the flat first bottom plate 52 has both the first seal portion 52a and the second valve seat 54 on the front and back sides. The first valve 12 and the second valve 13 are arranged on both sides of the flat first bottom plate 52. This allows the switching valve 10 (pilot switching valve 10) equipped with both the first valve 12 and the second valve 13 to be miniaturized.

[0041] Next, the opening and closing action of the selector valve 10 will be described with reference to Figures 2 and 7. In the selector valve 10 shown in Figure 2, the pushing portion 34 is separated from the second valve body 60. Therefore, due to the biasing force of the compression coil spring 82, the second seal surface 61a of the second valve body 60 contacts the second valve seat surface 54b to close the valve, and the first seal surface 53 of the first valve body 50 contacts the first valve seat surface 41c to close the valve. The first valve 12 and the second valve 13 are in a closed state.

[0042] Thereafter, when the pushing portion 34 descends and presses the second seal portion 61 of the second valve body 60, this pressing force is transmitted from the extension portion 62 of the second valve body 60 to the bottom surface 71b (see FIG. 3) of the retaining hole 71 of the second retaining member 70. Therefore, as shown in FIG. 7, the second valve body 60 and the second retaining member 70 are displaced in a direction away from the second valve seating surface 54b against the biasing force of the compression coil spring 82. As a result, the second seal surface 61a of the second valve body 60 moves away from the second valve seating surface 54b, and the second valve 13 is opened. Oil flowing into the third housing portion 43 (valve housing 40) from the second oil inlet 43c of the third housing portion 43 flows through the oil passage 73a and the oil passing flow path 75 of the second retaining member 70, passes through the gap between the second seal surface 61a and the second valve seating surface 54b, and then flows out of the valve housing 40.

[0043] When the second valve 13 is open, the first valve body 50 is not subjected to the biasing force of the compression coil spring 82. Therefore, the first seal surface 53 of the first valve body 50 moves away from the first valve seat surface 41c due to the oil pressure difference between the upstream and downstream sides of the second valve 13, and the first valve 12 is in the open state. As a result, the flow rate of the oil flowing through the flow path Fp can be increased.

[0044] Thereafter, when the second pushing member 32 rises, the pushing portion 34 moves away from the second seal portion 61 of the second valve body 60. As a result, the biasing force of the compression coil spring 82 causes the first valve 12 and the second valve 13 to return to the original closed state shown in FIG.

[0045] Next, an example of use of the switching valve 10 will be described with reference to Figures 8 and 9. The switching valve 10 can be provided in various oil devices, for example, a hydraulic shock absorber 100. The hydraulic shock absorber 100 constitutes a main part of a front fork mounted on the front of a saddle-ride type vehicle such as a motorcycle or tricycle. The hydraulic shock absorber 100 includes a telescopic body-side tube 101 and an axle-side tube 102 disposed on the body side and wheel side, respectively, and a compression coil spring (not shown) that biases these tubes 101, 102 in directions separating them from each other. The space enclosed by the tubes 101, 102 is filled with oil.

[0046] The lower end of the axle side tube 102 is provided with an axle side bracket 103. The lower part of the axle side tube 102 is provided with a bladder 104 and the switching valve 10. The bladder 104 can temporarily store excess oil in the axle side tube 102.

[0047] The switching valve 10 can open and close the flow path Fp for oil flowing between the axle-side tube 102 and the bladder 104. The lower part of the axle-side tube 102 has a bottomed valve mounting hole 105. As shown in FIG. 1 , the switching valve 10 can be attached to the axle-side tube 102 (see FIG. 8 ) by inserting the switching valve 10 into the valve mounting hole 105 and threading the actuator housing 24 into the inner circumferential surface 105a of the valve mounting hole 105. The bottom surface 43b (see FIG. 2 ) of the third housing portion 43 is pressed against the bottom surface 105b of the valve mounting hole 105, thereby fixing the valve housing 40 between the actuator housing 24 and the bottom surface 105b of the valve mounting hole 105.

[0048] Second Embodiment A switching valve 200 according to a second embodiment will be described with reference to FIGS.

[0049] Fig. 10 is a cross-sectional view illustrating a switching valve 200 according to the second embodiment, and corresponds to Fig. 1 illustrating the switching valve 10 according to the first embodiment. Fig. 11 is a cross-sectional view illustrating a valve device 211 according to the second embodiment, and corresponds to Fig. 2 illustrating the valve device 11 according to the first embodiment.

[0050] The switching valve 200 of the second embodiment shown in FIGS. 10 and 11 has the following configuration changes compared to the switching valve 10 of the first embodiment shown in FIGS. 1 and 2 . First, the valve device 11 is changed to a valve device 211. Second, the third housing portion 43 is changed to a third housing portion 243, which also serves as the second housing portion 42 of the first embodiment. Third, the first valve body 50 is changed to a first valve body 250, which also serves as the second retaining member 70 of the first embodiment. Fourth, the second valve body 60 is changed to a second valve body 260. Fifth, the biasing member 82 is changed to a biasing member 282. The rest of the basic configuration is common to the switching valve 10 of the first embodiment. The same reference numerals are used for parts common to the switching valve 10 of the first embodiment, and detailed description thereof will be omitted.

[0051] The switching valve 200 of the second embodiment will be described in detail below. As shown in Fig. 10 , the switching valve 200 has a configuration of an automatic valve in which, for example, a valve device 211 is driven by an actuator 20. However, the switching valve 200 is not limited to the configuration of an automatic valve. The valve device 211 is removably attached to the lower end of the booster mechanism 30.

[0052] 11, the valve device 211 has a so-called pilot changeover valve configuration, which includes a valve housing 240 and a first valve 212 and a second valve 213 housed in the valve housing 240. Hereinafter, the changeover valve 200 may be referred to as the "pilot changeover valve 200" as appropriate.

[0053] The first valve 212 is configured by combining a first valve seat surface 41c of the first housing portion 41 and a first seal portion 52a of the first valve body 250. This first valve 212 functions as the main valve of the pilot changeover valve 200 (changeover valve 200), and opens and closes by moving the first seal portion 52a toward and away from the first valve seat surface 41c. This first valve 212 may be referred to as the "main valve 212" as appropriate.

[0054] The second valve 213 is configured by combining the second valve seat surface 54b and the second seal portion 61 (see FIG. 12) of the second valve body 260. This second valve 213 has the function of the pilot valve of the pilot changeover valve 200 (changeover valve 200), and opens and closes by moving the second seal portion 61 toward and away from the second valve seat surface 54b. This second valve 213 may be referred to as the "pilot valve 213" as appropriate.

[0055] 11 and 12, the valve housing 240 includes a flat plate-shaped first housing portion 41 and a bottomed cylindrical third housing portion 243. These housing portions 41 and 243 may be integrally configured.

[0056] The third housing portion 243 also serves as the cylindrical second housing portion 42 (see FIG. 2) of Example 1. The third housing portion 243 can be fitted into one end surface 41 d of the first housing portion 41, and has a first oil inlet 42 a that penetrates radially inward and outward. Other configurations of the third housing portion 243 are the same as those of the third housing portion 43 of Example 1.

[0057] The first valve body 250 is guided by the inner circumferential surface 43g of the cylindrical portion 43a of the third housing portion 243 so as to be slidable along the axis CL of the first valve seat surface 41c. This first valve body 250 also serves as the second retaining member 70 of the first embodiment. The first valve body 250 may be referred to as the "retaining member 250" as appropriate. The other configurations of the first valve body 250 are the same as those of the first valve body 50 of the first embodiment.

[0058] The first valve body 250 is a cylindrical member with a bottom that is open on the bottom plate 43b side of the third housing part 243, and has an internal space 251 surrounded by the inner circumferential surface 51a of the first cylindrical part 51 and the first bottom plate 52. The internal space 251 can accommodate at least a portion of the second valve body 260 and the biasing member 282. The internal space 251 may be referred to as the "accommodation recess 251" as appropriate.

[0059] The second valve body 260 is fitted into the inner circumferential surface 51a of the first cylindrical portion 51 of the first valve body 250 and slidably held by this inner circumferential surface 51a. As shown in FIGS. 13A and 13B , the second valve body 260 is a resin-molded product, preferably made of a flexible resin, more preferably made of urethane resin (polyurethane) or nitrile rubber (NBR). The second valve body 260 is an integrally molded product including a second seal portion 61 having a second seal surface 61a, a large-diameter portion 262 extending from the second seal portion 61 toward the opposite side of the second seal surface 61a, and a small-diameter portion 263 extending from the large-diameter portion 262 toward the opposite side. The second seal portion 61, the large-diameter portion 262, and the small-diameter portion 263 are located on the axis CL of the second valve seat surface 54b (see FIG. 11 ).

[0060] The second seal portion 61 has the same configuration and function as the second seal portion 61 of the first embodiment (see FIG. 5), and therefore a description thereof will be omitted.

[0061] The large diameter portion 262 has a tapered (including substantially tapered) configuration that expands in diameter from the bottom portion 61b (boundary 61b) of the second seal portion 61 toward the opposite side of the second seal surface 61a. The tapered surface 262a (outer surface 262a) of this large diameter portion 262 preferably extends along a tangent line Tn to the curved second seal surface 61a. The surface 262b of the large diameter portion 262 opposite the bottom portion 61b of the seal portion 61 is referred to as the "bottom surface 262b of the large diameter portion 262." The surface 262c of the large diameter portion 262 at the portion with the largest diameter Cd is referred to as the "outer peripheral surface 262c of the large diameter portion 262."

[0062] The size of the diameter Cd of the outer peripheral surface 262c of the large diameter portion 262 is preferably set within a range that satisfies the following two conditions. The first condition is that the outer peripheral surface 262c of the large diameter portion 262 can slide smoothly relative to the inner peripheral surface 51a of the first cylindrical portion 51 of the first valve body 250 shown in Fig. 11. The second condition is that the radial offset of the large diameter portion 262 with respect to the axis CL of the second valve seat surface 54b shown in Fig. 11 can be made as small as possible.

[0063] The small diameter portion 263 extends from a bottom surface 262b of the large diameter portion 262 in a direction opposite to the bottom portion 61b of the seal portion 61. The small diameter portion 263 is cylindrical and has a smaller diameter than the outer circumferential surface 262c of the large diameter portion 262.

[0064] The overall shape of the second valve body 260 is what is called a "mushroom shape." A portion 264 of the second valve body 260 excluding the seal portion 61 may be referred to as an "extension portion 264" as appropriate. The extension portion 264 corresponds to the extension portion 62 of the first embodiment. The extension portion 264 is composed of a tapered large-diameter portion 262 (first extension portion 262) and a cylindrical small-diameter portion 263 (second extension portion 263).

[0065] When the second valve body 260 is molded from resin, traces 265 (molding traces 265) such as parting lines and discharge gates may be generated on the second valve body 260. In the second embodiment, the portion where the traces 265 may be generated is set in advance to the extension portion 264 of the second valve body 260, which does not require sealing. The traces 265 generated when the second valve body 260 is molded from resin are not removed but remain as they are on the extension portion 264. For example, the portion where the traces 265 may be generated is set to the outer circumferential surface 262c of the large diameter portion 262.

[0066] Referring also to Figure 14, a passage portion 273 is formed in the large diameter portion 262 of the second valve body 260. This passage portion 273 is configured to form part of a flow path Fp (see arrow Fp in Figure 10) through which oil flows when the second valve 13 is opened, that is, when the second seal surface 61a of the second valve body 260 moves away from the second valve seating surface 54b. This passage portion 273 includes the outer peripheral surface 262c of the large diameter portion 262, is formed on the tapered surface 262a (outer surface 262a), and penetrates the second valve seating surface 54b in the direction of the axis CL. This passage portion 273 includes the outer peripheral surface 262c of the large diameter portion 262 and is composed of at least one (preferably multiple) oil passages 273a formed in the tapered surface 262a. This oil passage 273a includes, for example, the outer peripheral surface 262c of the large diameter portion 262, and is configured by a flat surface or a groove formed on the tapered surface 262a, so that oil can pass through the oil passage 273a.

[0067] As shown in FIG. 14 , the bottom surface 262b of the large diameter portion 262 of the second valve body 260 is biased by a biasing member 282 in a direction that causes the second seal surface 61a to abut against the second valve seat surface 54b. This biasing member 282 is formed, for example, by a compression coil spring. The biasing member 282 may be referred to as the "compression coil spring 282" as appropriate. This compression coil spring 282 is interposed between the bottom plate 43b (see FIG. 11 ) of the third housing portion 43 and the bottom surface 262b of the large diameter portion 262. The position of the compression coil spring 282 relative to the first valve body 250 is determined by fitting it into the storage recess 251.

[0068] The compression coil spring 282 preferably has a "conical compression coil spring" configuration, with its end 282a, which contacts the bottom surface 262b of the large-diameter portion 262, tapered (i.e., with a smaller coil diameter). This is because the small-diameter portion 263 of the second valve body 260 can be fitted into the coil of the compression coil spring 282 with almost no gap. As a result, the coil center of the end 282a of the compression coil spring 282 can be aligned with the center (axis CL) of the second valve body 260. The end 282a of the compression coil spring 282 can bias the bottom surface 262b of the large-diameter portion 262 evenly.

[0069] The compression coil spring 282 restricts the position of the second valve body 260 within a range that maintains the open / closed position of the second seal surface 61a relative to the second valve seating surface 54b. For example, as shown in Fig. 15, when the center line QL of the second seal surface 61a is inclined with respect to the axis CL of the second valve seating surface 54b, the bottom surface 262b of the large diameter portion 262 and the small diameter portion 263 are also inclined along with the second seal surface 61a. At this time, the one end 282a of the compression coil spring 282 pressed by the small diameter portion 263 repels in a direction Rb that returns the small diameter portion 263 to the original axis CL.

[0070] In addition, as the bottom surface 262b of the large diameter portion 262 tilts, an uneven load acts on the one end 282a of the compression coil spring 282. At this time, reaction forces P1, P2 (biasing forces P1, P2) acting from the one end 282a to the bottom surface 262b of the large diameter portion 262 are uneven. The first reaction force P1 acts on the bottom surface 262b in a direction away from the one end 282a, while the first reaction force P2 acting to press the one end 282a deeper is greater. The difference between the reaction forces P1, P2 generates a moment in the second valve body 260 in a direction Rb that returns the center line QL of the second seal surface 61a to the axis CL of the second valve seat surface 54b.

[0071] In this way, the position of the second valve body 260 can be restricted by the bottom surface 262b of the large diameter portion 262, the small diameter portion 263, and the compression coil spring 282. The small diameter portion 263 and the compression coil spring 282 may be referred to as the "restriction portions 263, 282" as appropriate.

[0072] As shown in Figure 14, the first valve body 250 (holding member 250) directly holds the second valve body 260. In addition, the compression coil spring 282 directly biases the second valve body 260. Therefore, the second holding member 70 of the first embodiment shown in Figure 3 is not necessary. This allows the number of parts of the switching valve 200 to be reduced, and the switching valve 200 can be made smaller.

[0073] Next, the opening and closing action of the switching valve 200 will be described with reference to Figures 11, 14, and 16. In the switching valve 200 shown in Figures 11 and 14, the pushing portion 34 is separated from the second valve body 260. Therefore, due to the biasing force of the compression coil spring 282, the second seal surface 61a of the second valve body 260 contacts the second valve seat surface 54b to close the valve, and the first seal surface 53 of the first valve body 250 contacts the first valve seat surface 41c to close the valve. The first valve 212 and the second valve 213 are in a closed state.

[0074] Thereafter, when the pushing portion 34 descends and presses the second seal portion 61 of the second valve body 260, the second valve body 260 is displaced in a direction away from the second valve seating surface 54b against the biasing force of the compression coil spring 282. As a result, as shown in Fig. 16, the second seal surface 61a of the second valve body 260 moves away from the second valve seating surface 54b, and the second valve 213 enters an open state. The oil that flows into the third housing portion 243 (valve housing 240) from the second oil inlet 43c of the third housing portion 243 flows through the oil passing passage 273 and passes through the gap between the second seal surface 61a and the second valve seating surface 54b, before flowing out of the valve housing 240.

[0075] 16, when the second valve 213 is open, the first valve body 250 is not subjected to the biasing force of the compression coil spring 282. Therefore, the first seal surface 53 of the first valve body 250 moves away from the first valve seat surface 41c due to the oil pressure difference between the upstream and downstream sides of the second valve 213, and the first valve 212 is in the open state. As a result, the flow rate of the flow path Fp through which the oil flows can be increased.

[0076] Thereafter, when the second pushing member 32 rises, the pushing portion 34 moves away from the second valve body 260. As a result, the biasing force of the compression coil spring 282 returns the first valve 212 and the second valve 213 to their original closed state shown in FIG.

[0077] The operation and effects of the switching valve 200 of the second embodiment are the same as those of the switching valve 10 of the first embodiment. Furthermore, similar to the first embodiment, the switching valve 200 of the second embodiment can be provided in various oil devices, for example, the hydraulic shock absorber 100 (see FIGS. 8 and 9).

[0078] The above-described switching valves 10, 200 and the hydraulic shock absorber 100 including these switching valves 10, 200 can be summarized as follows.

[0079] 1, 2, 10, and 11. According to this embodiment, first, the switching valve 10, 200 includes a valve seat 54 (second valve seat 54) having a valve port 54a (second valve port 54a) that can communicate with the flow path Fp through which oil flows, and a valve seat surface 54b (second valve seat surface 54b) formed on the periphery of the valve port 54a. The switching valve 10, 200 further includes a member 60, 260 made of a resin molded product, i.e., a valve body 60, 260 (second valve body 60, 260), that moves toward and away from the valve seat surface 54b in a direction along the axis CL of the valve seat surface 54b to open and close the valve port 54a. The valve element 60, 260 includes a seal portion 61 (second seal portion 61) having a curved seal surface 61a (second seal surface 61a) that can abut against the valve seat surface 54b to seal, and an extension portion 62, 264 (see FIGS. 3 and 13A) that extends integrally from the seal portion 61 toward the opposite side of the seal surface 61a and retains traces 63, 265 (see FIGS. 3 and 13A) that were created during resin molding. The selector valve 10, 200 also includes a passage portion 73, 273 that can form part of the flow path Fp when the seal surface 61a of the valve element 60, 260 separates from the valve seat surface 54b. The selector valve 10, 200 also includes a restricting portion 71a, 263, 282 that restricts the position of the extension portion 62, 264 to maintain the open or closed position of the seal surface 61a relative to the valve seat surface 54b.

[0080] Thus, the resin-molded valve body 60, 260 is composed of a seal portion 61 having a curved sealing surface 61a and an integrally formed extension portion 62, 264 extending from the seal portion 61 toward the opposite side of the sealing surface 61a. Traces 63, 265 of parting lines, discharge gates, and other defects that may occur when the valve body 60, 260 is resin-molded are located on the extension portion 62, 264. Because the extension portion 62, 264 does not contact the valve seat surface 54b, it does not require sealing. Furthermore, the orientation of the extension portion 62, 264 is restricted by the restricting portions 71a, 263, 282. Even if the traces 63, 265 remain on the extension portion 62, 264, they do not affect the sealing performance of the sealing surface 61a against the valve seat surface 54b. Since there is no need to remove the traces 63, 265 from the extensions 62, 264, it is possible to reduce the production costs of the valve bodies 60, 260. In this way, it is possible to reduce costs while ensuring the sealing performance of the switching valves 10, 200 equipped with the valve bodies 60, 260 made of resin molded products.

[0081] 2. Secondly, preferably, the switching valve 10 according to the first aspect includes a holding member 70 (second holding member 70) that holds the extension portion 62. The passage portion 73 and the restricting portion 71 a are formed in the holding member 70.

[0082] By holding the extension 62 of the valve element 60 with the holding member 70, the position of the sealing surface 61a of the valve element 60 relative to the valve seat surface 54b is stabilized. This ensures that the sealing performance of the switching valve 10 is maintained. Furthermore, because the passage portion 73 having the oil passage 73a and the restricting portion 71a are provided in the holding member 70, a separate passage portion and restricting portion are not required. This allows the switching valve 10 to be made more compact.

[0083] 2 and 7. Thirdly, preferably, in the switching valve 10 described in the first and second aspects, the passage portion 73 is configured by an oil passage 73a formed in the outer peripheral surface 70c of the holding member 70 (second holding member 70), and penetrates the valve seat surface 54b in the direction of the axis CL.

[0084] The center of the retaining member 70 has a portion 71 (retaining hole 71) that retains the extension 62 of the valve body 60 (second valve body 60). On the other hand, there are no restrictions on the outer peripheral surface 70c of the retaining member 70. Since the oil passage 73a is formed on the outer peripheral surface 70c of the retaining member 70, a large cross-sectional area of ​​the oil passage 73a can be ensured.

[0085] 2 and 7. Fourth, preferably, in the switching valve 10 according to the third aspect, an oil passage 75 is formed around at least a portion of the outer circumferential surface 70c of the holding member 70 that holds the extension portion 62, the oil passage 75 being between the oil passage 73a and the valve seat 54 (second valve seat 54).

[0086] An oil passage 75 with a relatively large cross-sectional area can be provided on the outer peripheral surface 70c of the retaining member 70 near the valve seat 54. When the switching valve 10 is opened, oil can flow from the oil passage 73a through the oil passage 75, between the seal surface 61a of the valve body 60 and the valve seat surface 54b, and through the valve port 54a to the passage Fp. By ensuring a large cross-sectional area for the oil passage 75, oil resistance can be reduced, allowing the oil to flow more smoothly.

[0087] See Figures 2 and 4. Fifth, preferably, in the switching valve 10 described in any one of the second to fourth aspects, the retaining member 70 has a spring receiving recess 72 for receiving one end 82a of a compression coil spring 82 on an end surface 70b opposite to the portion 71 (retaining hole 71) that retains the extension portion 62. The bottom surface 72a of the spring receiving recess 72 is biased by the compression coil spring 82 in a direction that causes the seal surface 61a of the valve body 60 to abut against the valve seat surface 54b.

[0088] The compression coil spring 82 indirectly biases the valve body 60 via the retaining member 70. Therefore, even though the extension portion 62 is held by the retaining member 70, the compression coil spring 82 can stably bias the valve body 60 in the direction in which the seal surface 61 a abuts against the valve seat surface 54 b.

[0089] See Fig. 5. Sixth, preferably, in the switching valve 10 described in any one of the first to fifth aspects, the seal portion 61 has a hemispherical configuration. The extension portion 62 has a cylindrical configuration that is continuous with the bottom portion 61b (boundary 61b) of the seal portion 61 and has the same diameter as the diameter Bd of the bottom portion 61b.

[0090] The valve body 60 is a unitarily molded product of a hemispherical sealing portion 61 and a cylindrical extension portion 62, and is configured in a so-called bullet shape. Therefore, the valve body 60, in which the position of the extension portion 62 is restricted by the restricting portion 71a, can have an extremely simple configuration.

[0091] See Figures 2 and 5. Seventh, preferably, in the switching valve 10 according to any one of the second to sixth aspects, the valve body 60 (second valve body 60) is a resin molded product made of flexible resin. The holding member 70 (second holding member 70) has a holding hole 71 that holds the extension portion 62. The extension portion 62 is held by press-fitting into the holding hole 71. Note that examples of flexible resin that can be used include urethane resin (polyurethane) and nitrile rubber (NBR).

[0092] The valve body 60 is made of urethane resin. Even if the bottom surface 63 of the extension 62 remains intact, it can be easily press-fit into the holding hole 71 of the holding member 70, simplifying the holding configuration. The valve body 60 can be easily assembled to the holding member 70.

[0093] See Figures 10 and 14. Eighth, preferably, in the switching valve 200 described in the first aspect, the extension portion 264 includes a tapered large-diameter portion 262 (first extension portion 262) that expands in diameter from a bottom portion 61b (boundary 61b) of the seal portion 61 (second seal portion 61) toward the side opposite the seal surface 61a. The passage portion 273 is formed on an outer peripheral surface 262c of the large-diameter portion 262 and penetrates the valve seat surface 54b in the direction of the axis CL. The switching valve 200 includes a retaining member 250 (first valve body 250) that retains the outer peripheral surface 262c of the portion of the extension portion 264 where the outer diameter of the large-diameter portion 262 is largest.

[0094] The retaining member 250 retains the outer peripheral surface 262c of the largest diameter portion of the large diameter portion 262, which expands in diameter from the bottom portion 61b of the seal portion 61. In other words, the retaining member 250 can retain the portion of the valve body 260 that has a larger diameter than the seal portion 61. This allows the retaining member 250 to stably retain the valve body 260. Furthermore, the passage portion 273 is formed on the outer peripheral surface 262c of the large diameter portion 262. This allows the sealing performance of the seal portion 61 to be ensured without forming the passage portion 273 in the retaining member 250. This allows the retaining member 250 to be made more compact.

[0095] See Fig. 14. Ninth, preferably, in the switching valve 200 according to the eighth aspect, the extension portion 264 includes a cylindrical small-diameter portion 263 (second extension portion 263) that extends from the bottom surface 262b of the large-diameter portion 262 toward the opposite side from the bottom portion 61b of the seal portion 61 and has a smaller diameter than the bottom surface 262b of the large-diameter portion 262. The bottom surface 262b of the large-diameter portion 262 is biased by a compression coil spring 282 in a direction that causes the seal surface 61a of the valve body 260 to abut against the valve seat surface 54b. The small-diameter portion 263 is fitted into the coil of the compression coil spring 282. The restricting portions 263, 282 are formed by the small-diameter portion 263 and the compression coil spring 282.

[0096] The compression coil spring 282 directly biases the bottom surface 262b of the large diameter portion 262 of the valve body 260. Therefore, the compression coil spring 282 can stably bias the valve body 260 in the direction in which the seal surface 61a abuts against the valve seat surface 54b. Furthermore, the small diameter portion 263, which extends from the bottom surface 262b of the large diameter portion 262 to the side opposite the bottom portion 61b of the seal portion 61, is fitted into the coil of the compression coil spring 282. Therefore, the small diameter portion 263 and the compression coil spring 282 can simplify the configuration of the restriction portions 263, 282 that restrict the position of the valve body 260.

[0097] Please refer to Figure 8. Tenthly, the switching valve 10, 200 according to any one of the first to ninth aspects is preferably provided in the hydraulic shock absorber 100.

[0098] The hydraulic shock absorber 100 is provided with a switching valve 10, 200 that is equipped with a valve body 60, 260 made of a resin molded product to ensure sealing performance while reducing costs, so that the cost of the hydraulic shock absorber 100 can be reduced while ensuring the characteristics of the hydraulic shock absorber 100 itself.

[0099] The switching valves 10, 200 according to the present invention and the hydraulic shock absorber 100 including the switching valves 10, 200 are not limited to the above-described embodiments, as long as they achieve the functions and effects of the present invention. For example, the switching valves 10, 200 are not limited to an automatic valve configuration, and may be manually operated valves or check valves. Furthermore, the switching valves 10, 200 are not limited to a pilot-type valve configuration. Furthermore, the presence or absence of a booster mechanism 30 is optional, and the switching valves 10, 200 may be configured to be directly driven by the electromagnetic solenoid 20.

[0100] The switching valve 10, 200 of the present invention is suitable for use as a pilot type valve. Furthermore, the switching valve 10, 200 of the present invention and the hydraulic shock absorber 100 including the switching valve 10, 200 are suitable for use in saddle-ride type vehicles.

[0101] 10...switching valve, 54...valve seat (second valve seat), 54a...valve port (second valve port), 54b...valve seat surface (second valve seat surface), 60...valve body (second valve body), 61...seal portion (second seal portion), 61a...seal surface (second seal surface), 61b...bottom portion (boundary) of seal portion, 62...extension portion, 63...trace portion (molding trace), 70...retaining member (second retaining member), 70b...end surface opposite to portion retaining extension portion, 70c...outer circumferential surface, 71...portion retaining extension portion (retaining hole), 71a...regulating portion, 72...spring receiving recess, 72a...bottom surface of spring receiving recess, 73...passage portion, 73a...oil passage, 75...oil passing flow path, 82...compression coil spring, 82a...one end portion of compression coil spring, 100...hydraulic shock absorber, 200...switching valve, 250...retaining member (second retaining member, first valve body), 260...valve body (second valve body), 262...large diameter portion (first extension portion), 262b...bottom surface of large diameter portion, 262c...outer peripheral surface of large diameter portion, 263...small diameter portion (second extension portion, restriction portion), 264...extension portion, 265...trace portion (molding trace), 273...passage portion, 282...compression coil spring (restriction portion), Bd...diameter of bottom portion of seal portion, CL...axis line of valve seat surface, Fp...flow path through which oil flows.

Claims

1. A changeover valve comprising: a valve seat having a valve orifice capable of communicating with a flow path through which oil flows and a valve seat surface formed on the periphery of the valve orifice; a seal portion which is a resin molded product that moves in a direction along the axis of the valve seat surface so as to be able to approach and separate from the valve seat surface to open and close the valve orifice, the seal portion having a curved sealing surface that can come into contact with the valve seat surface to seal; and an extension portion which is formed integrally with the seal portion and extends in the opposite direction from the seal surface, the extension portion retaining traces created during resin molding; a passage portion which can form part of the flow path when the seal surface of the valve body moves away from the valve seat surface; and a regulating portion which regulates the attitude of the extension portion so as to maintain the open / closed position of the seal surface relative to the valve seat surface.

2. The switching valve according to claim 1, further comprising a holding member that holds said extension portion, said passage portion and said restriction portion being formed in said holding member.

3. A changeover valve as set forth in claim 2, wherein said passage portion is constituted by an oil passage formed on the outer circumferential surface of said retaining member and penetrates said valve seat surface in the axial direction.

4. A switching valve as described in claim 3, wherein an oil passage between the oil passage and the valve seat is formed around the entire outer circumferential surface of the retaining member, at least around the portion that retains the extension portion.

5. A switching valve as described in claim 2, wherein the retaining member has a spring receiving recess for receiving one end of a compression coil spring on the end face opposite to the portion that retains the extension portion, and the bottom surface of the spring receiving recess is biased by the compression coil spring in a direction such that the sealing surface of the valve body abuts against the valve seat surface.

6. A switching valve as described in claim 1, wherein the sealing portion is semi-spherical in configuration, and the extension portion is cylindrical in configuration, continuing from the bottom portion of the sealing portion and having the same diameter as the diameter of the bottom portion.

7. A switching valve as described in claim 2, wherein the valve body is a resin molded product made of flexible resin, the retaining member has a retaining hole that retains the extension portion, and the extension portion is retained by press-fitting into the retaining hole.

8. A switching valve as described in claim 1, wherein the extension portion includes a tapered large diameter portion which expands in diameter from the bottom portion of the seal portion in a direction opposite to the seal surface, the passage portion is formed on the outer peripheral surface of the large diameter portion and penetrates the valve seat surface in the axial direction, and the passage portion further includes a retaining member which retains the outer peripheral surface of the portion of the large diameter portion in the extension portion which has the largest outer diameter.

9. A switching valve as described in claim 8, wherein the extension portion extends from a bottom surface of the large diameter portion in a direction opposite to the bottom portion of the sealing portion and includes a cylindrical small diameter portion having a smaller diameter than the bottom surface of the large diameter portion, the bottom surface of the large diameter portion is biased by a compression coil spring in a direction such that the sealing surface of the valve body abuts the valve seat surface, the small diameter portion is fitted within the coil of the compression coil spring, and the regulating portion is constituted by the small diameter portion and the compression coil spring.

10. A hydraulic shock absorber equipped with the switching valve of claim 1.

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