Spool type switching valve

Abstract

To provide a spool type switching valve in which a spool valve and a piston can be combined efficiently.SOLUTION: A spool type switching valve has first and second piston chambers 32 at both end parts of a spool hole 25 extending in an axial L direction, where first and second spool valves 11b are housed in the spool hole, and first and second pistons 33 are housed in the piston chambers. First and second connection parts 70b are provided between a valve end surfaces 34 formed at the end part of the spool valves and a piston end surface 33a of the piston facing it. The connection parts have a protrusion part 72 protruding from the valve end surface, and an insertion recess part 77 on the inside of a wall part 36 erected on the piston end surface. An engagement groove part 73 is provided in the protrusion part. The wall part has a notched groove part cut out in the axial direction, a leg part arranged inside the notched groove part, and an engagement claw part 47 provided at the tip part of the leg part. With the protrusion part inserted into the insertion recess part, the engagement claw part and the engagement groove part engage with each other to connect the spool valve and the piston.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a spool type switching valve in which a spool valve slidably accommodated in a spool hole is driven by a piston. [Background technology]

[0002] In a spool-type switching valve in which a piston drives a spool valve slidably housed in a spool hole, the spool valve and the piston are formed separately and connected to each other by a connecting part, it is already known, for example as described in Patent Document 1. The connecting part is formed by mutually engaging an engaging part provided on the spool valve and an engaged part provided on the piston.

[0003] In such conventional spool-type switching valves, a structure has generally been adopted as the connecting portion 112 between the spool valve and the piston, in which the spool valve 110 and the piston 111 are moved relative to each other in a direction perpendicular to their respective axes, so that an engaging portion 113 and an engaged portion 114 are engaged with each other, as shown in FIG. 12.

[0004] However, in such a conventional connecting structure, in order to connect the spool valve 110 and the piston 111, as described above, it is necessary to move the spool valve 110 and the piston 111 relative to each other in a direction perpendicular to their respective axes, which tends to make the connecting process complicated and is not necessarily efficient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-24345 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the technical object of the present invention is to provide a spool type switching valve in which a spool valve and a piston are formed separately and connected to each other, which is capable of connecting the spool valve and the piston more efficiently. [Means for solving the problem]

[0007] In order to achieve the above object, a spool type switching valve according to the present invention comprises a body having a spool hole extending in an axial direction and a piston chamber at an axial end of the spool hole, a spool valve slidably accommodated in the spool hole, and a piston slidably accommodated in the piston chamber, the body being provided with ports for intake, exhaust and output, and the spool valve is driven together with the piston by supplying and discharging pilot air to and from the piston chamber, thereby enabling selective switching of a communication state between the ports, and a connecting portion is provided between a valve end face formed at an end of the spool valve on the piston chamber side in the axial direction and a piston end face of the piston opposing the valve end face, the connecting portion being provided between the valve end face of the spool valve and a piston end face of the piston opposing the valve end face, and an insertion recess provided on the piston end face of the piston and into which the protrusion is inserted, the protrusion having an engagement groove provided around the axis, the insertion recess being formed inside an annular wall portion erected from the piston end face, the wall portion including a cutout groove portion cut out along the axial direction, and an engagement portion provided in the cutout groove portion and engaged with the engagement groove portion, the engagement portion having a leg portion extending along the axial direction and having a base end portion connected to the piston end face, and an engagement claw portion provided at a tip portion of the leg portion protruding radially inwardly around the axis, the engagement claw portion engaging with the engagement groove portion when the protrusion is inserted into the insertion recess, and the leg portion being elastically deformable radially outwardly around the axis.

[0008] In this case, the engaging claw preferably has a radially inner tip end having an inclined surface that inclines radially outward toward the valve end face of the spool valve. Also, preferably, a recess is provided in the piston end face on which the leg is provided, and a base end of the leg is erected from a bottom surface of the recess.

[0009] In addition, preferably, a stopper portion against which the tip of the protrusion abuts is provided at the bottom of the insertion recess, and when the tip of the protrusion abuts against the stopper portion, a gap is formed between the valve end face of the spool valve and the tip of the engagement portion facing it.

[0010] Preferably, the protrusion of the spool valve and the stopper of the piston abut against each other by flat end faces perpendicular to the axis. Also, preferably, the tip of the engagement portion and a top surface of the wall portion facing the valve end face are located on the same plane perpendicular to the axial direction.

[0011] Preferably, the wall portion has a plurality of cutout grooves formed at equal angular intervals around the axis.

[0012] In addition, preferably, the piston chambers are provided at both axial ends of the spool hole, a piston is accommodated in each of the piston chambers, the two spool valves are accommodated coaxially in the spool hole, the axial length of the spool hole is longer than the combined axial length of the two spool valves, and the two spool valves accommodated in the spool hole and the pistons arranged adjacent to each of the spool valves are connected by the connecting portions. Effect of the Invention

[0013] As described above, according to the present invention, in a spool type switching valve in which a spool valve and a piston are formed separately and connected to each other, it is possible to provide a spool type switching valve in which the spool valve and the piston can be connected more efficiently. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view of a spool-type switching valve according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a plan view of a spool type switching valve. [Diagram 3] FIG. 2 is a side view of a spool type switching valve. [Figure 4] 4 is a cross-sectional view of the spool type switching valve taken along line IV-IV of FIG. 2. [Diagram 5] FIG. 4 is a side view of the second piston. [Figure 6] FIG. 4 is a rear view of the second piston. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a portion viewed from the arrow VII in FIG. [Figure 8] FIG. 11 is an enlarged cross-sectional view of the coupling diagram when the second piston has moved to a forward position. [Figure 9] 9 is a cross-sectional view of the coupling portion taken along line IX-IX in FIG. 8. [Figure 10] FIG. 11 is an explanatory diagram illustrating a state in which a second piston is connected to a second spool valve. [Figure 11] FIG. 11 is an enlarged perspective view of a portion viewed from an arrow XI in FIG. [Figure 12] FIG. 13 is an explanatory diagram illustrating a conventional method for connecting a piston to a spool valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A spool type switching valve according to the present invention will be described below. In this embodiment, a pilot type solenoid valve in which two spool valves are accommodated in a spool hole will be described as an example of the spool type switching valve.

[0016] As shown in Figs. 1 to 4, the spool type switching valve 1 includes a main valve section 10 incorporating first and second spool valves 11a, 11b, and a pilot valve section 40 including first and second pilot solenoid valves 41a, 41b. The main valve section 10 includes a main valve body 13 which is a body of the main valve section 10 and is formed in a rectangular parallelepiped shape extending in the front-rear direction perpendicular to the width direction. A port block 15 including first and second output ports 14a, 14b is attached to the front end of the main valve body 13. The pilot valve section 40 includes a pilot body 43 which is a body of the main valve section 10 and is connected to the rear end of the main valve body 13.

[0017] A pair of opposing side surfaces 16a, 16b, 44a, 44b of the main valve body 13 and the pilot body 43 are each provided with a switching valve air supply opening 17 through which air is supplied, a switching valve exhaust opening 18 through which air is exhausted, a switching valve pilot supply opening 19 through which pilot air is supplied, and a switching valve pilot exhaust opening 20 through which pilot air is exhausted.

[0018] In this embodiment, the switching valve air intake opening 17 and the switching valve exhaust opening 18 open in the front lower parts of the side surfaces 16a, 16b, respectively. In addition, in the front-rear direction, the switching valve pilot supply openings 19 opened in each of the side surfaces 16a, 16b are disposed horizontally rearward of the switching valve exhaust opening 18. In addition, the switching valve pilot exhaust opening 20 is disposed above and rearward of the switching valve pilot supply opening 19.

[0019] The switching valve air intake openings 17, 17 communicate with each other through a switching valve air intake communication passage 21 formed in the main valve body 13. The switching valve exhaust openings 18, 18 communicate with each other through a switching valve exhaust communication passage 22 formed in the main valve body 13. Furthermore, the switching valve pilot supply openings 19, 19 communicate with each other through a switching valve pilot supply passage 23 formed in the main valve body 13. The switching valve pilot exhaust openings 20, 20 communicate with each other through a switching valve pilot exhaust passage 24 formed in the main valve body 13.

[0020] Next, we will explain the main valve section 10 of the spool type switching valve 1. As shown in Figure 4, the main valve section 10 has a piston box 60 attached to the rear end surface of the main valve body 13, and a port block 15 attached to the front end surface of the main valve body 13.

[0021] A spool hole 25 is formed between both front and rear end faces of the main valve body 13, penetrating along the axis L. The spool hole 25 communicates with an intake passage 26 located in the center in the direction of the axis L, first and second output passages 27a, 27b located on both sides of the intake passage 26, and first and second exhaust passages 28a, 28b located on both sides of the intake passage 26. The first and second exhaust passages 28a, 28b communicate with each other through the switching valve exhaust communication passage 22.

[0022] The first spool valve 11a is inserted into the rear side of the spool hole 25 so as to be slidable along the axis L, and the second spool valve 11b is inserted into the front side of the spool hole 25 so as to be slidable along the axis L. That is, the first and second spool valves 11a, 11b are housed in the spool hole 25 on the same axis L. The length of the spool hole 25 in the axial direction L is longer than the sum of the axial lengths of the first and second spool valves 11a, 11b.

[0023] Each of the spool valves 11a and 11b has a first land portion 12a located at the center in the direction of the axis L, a second land portion 12b and a third land portion 12c located on both sides of the first land portion 12a, and a shaft portion 12d connecting adjacent land portions. The shaft portion 12d has a smaller diameter than the land portions 12a and 12c.

[0024] In these spool valves 11a and 11b, a first seal member 29a is attached to the outer periphery of the first land portion 12a, and a second seal member 29b is attached to the outer periphery of the second land portion 12b. Also, a third seal member 29c is attached to the outer periphery of the third land portion 12c. In this embodiment, the third seal member 29c is a lip-type seal member that opens toward the first land portion 12a side.

[0025] In the first spool valve 11a, the first seal member 29a opens and closes the first exhaust passage 28a connecting the first output port 14a and the switching valve exhaust opening 18 (see FIG. 3). In the first spool valve 11a, the second seal member 29b opens and closes the air supply passage 26 connecting the first output port 14a and the switching valve air supply opening 17 (see FIG. 3). In the first spool valve 11a, the third seal member 29c allows air to flow from the first piston chamber 61 side to the first exhaust passage 28a side, while preventing air from flowing out from the first exhaust passage 28a side to the first piston chamber 61 side.

[0026] In the second spool valve 11b, the first seal member 29a opens and closes the second exhaust passage 28b connecting the second output port 14b and the switching valve exhaust opening 18 (see FIG. 3). In the second spool valve 11b, the second seal member 29b opens and closes the air supply passage 26 connecting the second output port 14b and the switching valve air supply opening 17 (see FIG. 3). In the second spool valve 11b, the third seal member 29c allows air to flow from the second piston chamber 32 side to the second exhaust passage 28b side, but prevents air from flowing out from the second exhaust passage 28b side to the second piston chamber 32 side.

[0027] The piston box 60 is formed with a first piston chamber 61 that opens forward. A first piston 62 having a diameter larger than that of the first spool valve 11a is inserted into the first piston chamber 61 so as to be slidable in the direction of the axis L. The port block 15 is formed with a second piston chamber 32 that opens rearward. A second piston 33 having a diameter larger than that of the second spool valve 11b is inserted into the second piston chamber 32 so as to be slidable in the direction of the axis L.

[0028] The first spool valve 11a and the first piston 62, which are adjacent in the direction of the axis L, are connected by a first connecting portion 70a. The second spool valve 11b and the second piston 33 are connected by a second connecting portion 70b. Since the first and second connecting portions 70a, 70b are configured in the same way, only the second connecting portion 70b will be described, and a description of the first connecting portion 70a will be omitted.

[0029] 5 to 11, the second connecting portion 70b connects between the valve end surface 34 formed at the end portion of the second spool valve 11b on the second piston chamber 32 side in the axial direction L and the opposing piston end surface 33a of the second piston 33. The second connecting portion 70b has a protrusion 72 protruding from the valve end surface 34 of the second spool valve 11b, and an insertion recess 77 provided on the piston end surface 33a of the second piston 33 and into which the protrusion 72 is inserted.

[0030] In this embodiment, the valve end surface 34 is formed in an annular shape extending in a direction perpendicular to the axis L (hereinafter referred to as the radial direction). A cylindrical protrusion 72 protrudes from this valve end surface 34. The protrusion 72 extends coaxially with the axis L, and an engagement groove 73 is provided around the axis L on the rear side of the protrusion 72. The protrusion 72 has an outer shape formed in a polygonal shape around the axis L. In this embodiment, the protrusion 72 has an outer shape formed in an octagonal shape. The protrusion 72 has a smaller diameter than the outer diameter of the third land portion 12c of the second spool valve 11b.

[0031] A flat end surface 74 extending in the radial direction is provided at the tip end (front end in the direction of the axis L) of the protruding portion 72. This flat end surface 74 abuts against a flat end surface 35a of the stopper portion 35 of the second piston 33, which will be described later.

[0032] The second piston 33 is formed in a cylindrical shape. The second piston 33 has a front surface 33b on which pilot air acts and a piston end surface 33a which is a back surface facing away from the front surface 33b. The front surface 33b and the piston end surface 33a extend in the radial direction. As shown in Figs. 5 to 11, an annular wall portion 36 is provided on the piston end surface 33a. An insertion recess 77 is formed on the inner side of the wall portion 36.

[0033] The inner surface of the insertion recess 77 is formed in a polygonal shape around the axis L when viewed in the direction of the axis L. In this embodiment, the wall 36 is formed in a cylindrical shape, and the insertion recess 77 is formed in an octagonal shape similar to the outer shape of the protruding portion 72 of the second spool valve 11b. Therefore, by inserting the protruding portion 72 into the insertion recess 77, the second spool valve 11b and the second piston 33 can be integrally connected around the axis L.

[0034] The wall 36 includes a notched groove 37 cut along the axis L, and an engagement portion 38 provided in the notched groove 37 and engaged with the engagement groove 73. The engagement portion 38 has a leg 39 extending along the axis L and having a base end connected to the piston end surface 33a, and an engagement claw 47 provided at the tip of the leg 39 protruding radially inwardly with the axis L as the center. In this embodiment, the notched groove 37 is provided in the wall 36 at positions facing each other with the axis L at the center. That is, the notched groove 37 is formed at equal angular intervals (about 180 degrees) around the axis L in the wall 36. The tip of the notched groove 37 opens at the tip of the wall 36, and the base end of the notched groove 37 communicates with a recess 33c provided in the piston end surface 33a. The recess 33 c extends radially outward from the base end of the cutout groove 37 and opens onto the outer circumferential surface of the second piston 33 .

[0035] The legs 39 are disposed at positions spaced from a pair of inner surfaces of the walls that divide the cutout groove 37. The legs 39 stand upright from the bottom surface of the recess 33c and extend along the axis L direction within the cutout groove 37. In this embodiment, the legs 39 are formed in a rectangular parallelepiped shape, and a hole 39a penetrating in the radial direction is provided in an intermediate portion of the legs 39. The legs 39 are elastically deformable in the radial direction.

[0036] The engagement claws 47 protrude into and engage with the engagement grooves 73 with the protrusions 72 inserted into the insertion recesses 77. The engagement claws 47 have an inclined surface 47a at their radially inner tips that incline radially outward toward the valve end surface 34 of the second spool valve 11b. Therefore, when the tip of the protrusion 72 is pressed against the inclined surface 47a when the protrusion 72 is inserted into the insertion recesses 77, the engagement claws 47 are easily opened radially outward with the elastic deformation of the legs 39, thereby enabling the protrusion 72 to be smoothly inserted into the insertion recesses 77.

[0037] Furthermore, the tip of the engagement portion 38 and the top surface 36a facing the valve end surface 34 of the wall portion 36 are located on the same plane perpendicular to the axis L. That is, the claw portion end surface 47b of the engagement claw portion 47 facing the valve end surface 34 and the top surface 36a of the wall portion 36 are located on the same plane perpendicular to the axis L. Note that the tip of the engagement portion 38 may protrude toward the valve end surface 34 beyond the top surface 36a of the wall portion 36.

[0038] 6 and 9, the protrusion 72 of the second spool valve 11b abuts against the piston end face 33a (stopper portion 35) of the second piston 33 by abutment between flat end faces 74, 35a perpendicular to the axis L. Specifically, the stopper portion 35 against which the tip end of the protrusion 72 abuts is provided at the bottom of the insertion recess 77, and this stopper portion 35 is a flat end face 35a extending in a radial direction perpendicular to the axis L.

[0039] In this embodiment, the flat end surface 35a is formed on the same plane as the piston end surface 33a, and is formed in an elliptical shape when viewed in the direction of the axis L. The elliptical flat end surface 35a is formed symmetrically with respect to a central axis L1 that passes through the center of the bottom of the insertion recess 77 and connects the pair of legs 39. The shape of the flat end surface 35a is not limited to an elliptical shape, and may be a circle, a rectangle, or the like. A groove 35b is provided in the flat end surface 35a.

[0040] On the other hand, the valve end surface 34 of the protruding portion 72 of the second spool valve 11b is provided with a flat end surface 74 that is perpendicular to the axis L. In this embodiment, the flat end surface 74 is also formed in an elliptical shape similar to the flat end surface 35a. When the protruding portion 72 is inserted into the insertion recess 77, the flat end surface 74 can come into contact with the flat end surface 35a in a tight contact state.

[0041] 7 and 8 show a state in which the second piston 33 moves to the rear end position (retracted position) and the front end position (advanced position) of the second piston chamber 32, and the tip of the protruding portion 72 abuts against the stopper portion 35. In this state, the second connecting portion 70b forms a gap 48 between the valve end surface 34 of the second spool valve 11b and the tip of the engaging portion 38 facing thereto. In this embodiment, this gap 48 is formed between the valve end surface 34 of the second spool valve 11b and the claw portion end surface 47b of the engaging claw portion 47 facing thereto. Therefore, there is no risk that the valve end surface 34 of the second spool valve 11b abuts against the engaging claw portion 47, and damage to the engaging portion 38 can be prevented in advance.

[0042] Next, the pilot valve section 40 will be described. As shown in Fig. 4, the pilot valve section 40 is provided with first and second pilot solenoid valves 41a and 41b for driving the first and second spool valves 11a and 11b. The first and second pilot solenoid valves 41a and 41b each include a first and second pilot inlet flow passage 79a and 79b, a first and second pilot output flow passage 80a and 80b, and a first and second pilot exhaust flow passage 81a and 81b. The first and second pilot solenoid valves 41a and 41b are configured to selectively communicate the first and second pilot output flow passages 80a and 80b with the first and second pilot inlet flow passages 79a and 79b or the first and second pilot exhaust flow passages 81a and 81b by energizing and de-energizing the solenoids 41a1 and 41b1.

[0043] The first and second pilot inlet passages 79a, 79b communicate with the switching valve pilot supply passage 23 through a pilot input passage 109 formed to straddle the pilot body 43 and the main valve body 13. In addition, the first pilot output passage 80a communicates with the first piston chamber 61 through a first pilot supply communication passage 104a formed to straddle the pilot body 43 and the piston box 60. In addition, the second pilot output passage 80b communicates with the second piston chamber 32 through a second pilot supply communication passage 104b formed across the pilot body 43, the piston box 60, and the main valve body 13. Furthermore, the first and second pilot exhaust passages 81a, 81b communicate with a pilot discharge passage 105 formed across the pilot body 43 and the piston box 60. In addition, the pilot discharge passage 105 communicates with the switching valve pilot exhaust passage 24 on the upstream side thereof.

[0044] The pilot discharge passage 105 extends across the pilot body 43 and the piston box 60, and further extends to the first exhaust passage 28a through a gap formed between the third seal member 29c and the spool hole 25. The third seal member 29c is a lip-type seal member that opens toward the second land portion 12b side, and allows air to flow from the first piston 62 side to the first exhaust passage 28a side, while preventing air from flowing from the first exhaust passage 28a side to the first piston 62 side.

[0045] Each of the first and second pilot solenoid valves 41a, 41b includes a pilot valve body 82 on the front side. The pilot valve body 82 includes inlet valve bodies 45a, 45b and exhaust valve bodies 46a, 46b that are arranged in the front-rear direction and interlock with each other. When the solenoid 41a1 or the solenoid 41b1 is excited, the inlet valve body 45a or the inlet valve body 45b is opened to individually communicate the first pilot inlet flow path 79a and the first pilot output flow path 80a, or the second pilot inlet flow path 79b and the second pilot output flow path 80b. When the solenoid 41a1 or the solenoid 41b1 is excited, the exhaust valve body 46a or the exhaust valve body 46b is closed to block the flow path from the first pilot output flow path 80a or the second pilot output flow path 80b to the pilot discharge flow path 105. As a result, pilot air is supplied to the first piston chamber 61 or the second piston chamber 32.

[0046] When the solenoid 41a1 or 41b1 is de-energized, the inlet valve bodies 45a, 45b are closed and the exhaust valve bodies 46a, 46b are opened. Then, the flow path from the first pilot output flow path 80a or the second pilot output flow path 80b to the first pilot exhaust flow path 81a or the second pilot exhaust flow path 81b is opened, and the air supplied to the first piston chamber 61 or the second piston chamber 32 is individually discharged. As a result, the acting force of the air flowing from the switching valve intake communication flow path 21 through the intake flow path 26 into the spool hole 25 becomes the returning force of the first and second spool valves 11a, 11b, and the first and second spool valves 11a, 11b perform the returning operation.

[0047] Next, a description will be given of a connecting operation for connecting the second spool valve 11b and the second piston 33. As shown in Fig. 10, the second piston 33 is disposed on the tip side of the protruding portion 72 of the second spool valve 11b with the insertion recess 77 of the second piston 33 facing the second spool valve 11b. Then, at least one of the second spool valve and the second piston 33 is moved in a direction approaching each other to insert the protruding portion 72 into the insertion recess 77. As a result, the engaging claw portion 47 of the second piston 33 and the engaging groove portion 73 of the second spool valve 11b are engaged with each other, and the second spool valve 11b and the second piston 33 are connected to each other.

[0048] In this manner, the second spool valve 11b and the second piston 33 can be coupled to each other by linearly moving the second spool valve 11b and the second piston 33 closer to each other. This simplifies the coupling process, and the second spool valve 11b and the second piston 33 can be efficiently coupled to each other. [Explanation of symbols]

[0049] 1 Spool type switching valve 11a First spool valve (spool valve) 11b Second spool valve (spool valve) 13 Main valve body (body) 14a 1st output port (output port) 14b Second output port (output port) 15 Port block (body) 17 Switching valve air intake opening (air intake port) 18 Switching valve exhaust opening (exhaust port) 25 spool hole 32 Second piston chamber (piston chamber) 33 Second piston (piston) 33a Piston end face 33c Recess 34 Valve end face 35 Stopper part 35a, 74 flat end surface 36 Wall 36a top surface 37 Notched groove 38 Engagement part 39 Legs 47 Engagement claw 47a Slope 48 Gap 60 Piston box (body) 61 First piston chamber (piston chamber) 62 First piston (piston) 70a 1st connection part (connection part) 70b 2nd connecting part (connecting part) 72 Protrusion 73 Engagement groove 77 Insertion recess L axis line (axis)

Claims

1. A spool type switching valve comprising: a body having a spool hole extending in an axial direction and a piston chamber at an axial end of the spool hole; a spool valve slidably accommodated in the spool hole; and a piston slidably accommodated in the piston chamber, wherein the body is provided with ports for air supply, exhaust, and output, and the spool valve is driven together with the piston by supplying and exhausting pilot air to and from the piston chamber, thereby enabling selective switching of a communication state between the ports, a connecting portion is provided between a valve end surface formed at an end portion of the spool valve on the piston chamber side in the axial direction and a piston end surface of the piston opposed thereto, the connecting portion connecting the valve end surface and the piston, the connecting portion includes a protruding portion protruding from the valve end surface of the spool valve and an insertion recessed portion provided on the piston end surface of the piston into which the protruding portion is inserted, The protruding portion is provided with an engagement groove portion around the axis, The insertion recess is formed on the inside of an annular wall portion extending from the piston end surface, The wall portion includes a cutout groove portion cut along the axial direction, and an engagement portion provided in the cutout groove portion and engaged with the engagement groove portion, The engaging portion has a leg portion extending along the axial direction and a base end portion connected to the piston end surface, and an engaging claw portion provided at a tip end portion of the leg portion and protruding radially inward around the axis, the engaging claw portion is engaged with the engaging groove portion in a state in which the protrusion portion is inserted into the insertion recess portion, The leg portion is elastically deformable radially outwardly about the axis. A spool type switching valve characterized by:

2. The engaging claw portion has an inclined surface at a radially inner tip portion thereof, the inclined surface inclining radially outward toward the valve end surface of the spool valve.

2. The spool type switching valve according to claim 1 .

3. The piston end surface on which the leg is provided is provided with a recess, The base end of the leg is erected from the bottom surface of the recess.

2. The spool type switching valve according to claim 1 .

4. a stopper portion against which a tip end of the protrusion abuts is provided at a bottom of the insertion recess, When the tip of the protrusion is in contact with the stopper, a gap is formed between the valve end surface of the spool valve and the tip of the engagement portion facing the valve end surface.

2. The spool type switching valve according to claim 1 .

5. The protrusion of the spool valve and the stopper of the piston abut against each other by flat end surfaces perpendicular to the axis.

5. The spool type switching valve according to claim 4.

6. A tip end of the engagement portion and a top surface of the wall portion facing the valve end surface are located on the same plane perpendicular to the axial direction.

5. The spool type switching valve according to claim 4.

7. In the wall portion, a plurality of the notched groove portions are formed at equal angular intervals around the axis.

2. The spool type switching valve according to claim 1 .

8. The piston chamber is provided at both axial ends of the spool hole, The piston is accommodated in each of the piston chambers, The two spool valves are coaxially housed in the spool hole, The axial length of the spool hole is longer than the sum of the axial lengths of the two spool valves, The two spool valves accommodated in the spool holes and the pistons disposed adjacent to each of the spool valves are connected by the connecting portion.

8. The spool type switching valve according to claim 1, wherein the valve is a spool type switching valve.

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