Rotary valve

Abstract

To reduce a running torque of a valve body.SOLUTION: A housing 12 has an inflow port and an outflow port for fluid. A valve body 31 has a valve body part 32 that is stored in the housing 12. A support mechanism M1 for rotatably supporting the valve body 31 in the housing 12 comprises: a bearing hole 51 that extends in a direction along a second axis line AL2 of the housing 12 in the valve body part 32, and which has an opening part 54 at one end and also has an inner bottom surface 55 at the other end; and a shaft part 61 that projects in a direction along the second axis line AL2 from the housing 12, and which is inserted into the bearing hole 51. The inner bottom surface 55 is composed by a plane 56 orthogonal to the second axis line AL2. A tip surface 64 of the shaft part 61 is composed by a curved surface 65 that is curved into a spherical shape to swell toward the inner bottom surface 55. The tip surface 64 is kept in contact with the inner bottom surface 55 at a place where the second axis line AL2 passes in the curved surface 65.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a rotary valve. [Background technology]

[0002] There is known a rotary valve that switches the flow pattern of a fluid in a flow path by rotating a valve body (see, for example, Patent Document 1). As shown in Fig. 17 and Fig. 18, a rotary valve 100 includes a valve body 105 having a first axis AL1, a housing 101 having a second axis AL2, and a support mechanism M1 that rotatably supports the valve body 105 on the housing 101. The housing 101 has an inlet and an outlet 104 for a fluid FL. The valve body 105 has a valve main body portion 106 that is accommodated in the housing 101 with the first axis AL1 aligned with the second axis AL2.

[0003] The support mechanism M1 includes a bearing hole 107 provided in the valve body 106 and a shaft portion 111 provided in the housing 101. The bearing hole 107 extends in the valve body 106 in a direction along the second axis AL2. The bearing hole 107 has an opening 108 at one end in the direction along the second axis AL2, and has an inner bottom surface 109 at the other end. The shaft portion 111 protrudes from the housing 101 in the direction along the second axis AL2, and is inserted into the bearing hole 107.

[0004] The inner bottom surface 109 and the tip surface 112 of the shaft portion 111 are both formed by planes perpendicular to the second axis AL2. The inner bottom surface 109 and the tip surface 112 are in contact with each other, so that the valve body 105 is supported by the housing 101 via the shaft portion 111.

[0005] In the rotary valve 100 having the above configuration, when the valve element 105 rotates about the first axis AL1, the communication state of the inlet and the outlet 104 by the valve element 105 is changed. Accordingly, the flow pattern of the fluid FL in the flow path is changed. For example, when the inlet and the outlet 104 are connected, the fluid FL can flow through the flow path through the rotary valve 100. On the other hand, when the inlet and the outlet 104 are no longer connected, the fluid FL is blocked from flowing through the flow path through the rotary valve 100. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2022-152801 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional rotary valve 100 described above, the valve element 105 is rotated relative to the housing 101 with the inner bottom surface 109, which is a flat surface, in surface contact with the tip surface 112, which is also a flat surface. The area of ​​contact between the inner bottom surface 109 and the tip surface 112 (contact area) is large. As a result, the frictional force generated between the inner bottom surface 109 and the tip surface 112 is large. As a result, the rotational torque required to rotate the valve element 105 increases. [Means for solving the problem]

[0008] Various aspects of a rotary valve for solving the above problems will be described below. [Aspect 1] A rotary valve comprising a valve element having a first axis, a housing having a second axis, and a support mechanism rotatably supporting the valve element on the housing, the housing having an inlet and an outlet for a fluid, the valve element having a valve body portion housed in the housing with the first axis coinciding with the second axis, and a communication state of the inlet and the outlet is changed by rotation of the valve element about the first axis, the support mechanism extending in a direction along the second axis on one of the housing and the valve body portion, and a rotary valve comprising: a bearing hole having an opening at one end and an inner bottom surface at the other end; and a shaft portion protruding from the other end in a direction along the second axis and inserted into the bearing hole, the inner bottom surface being formed by a plane perpendicular to the second axis or a curved surface that is spherically curved so as to bulge toward the opening, at least a region of a tip surface of the shaft portion that includes the second axis being formed by a curved surface that is spherically curved so as to bulge toward the inner bottom surface, and the tip surface being in contact with the inner bottom surface at a point of the curved surface of the tip surface through which the second axis passes.

[0009] According to the above configuration, when the valve body is supported on the housing by the support mechanism, the inner bottom surface of the bearing hole and the tip surface of the shaft portion inserted into the bearing hole come into contact with each other. Here, the curved surface of the tip end surface of the shaft portion that constitutes at least the region including the second axis is curved spherically so as to bulge toward the inner bottom surface, and the point of this curved surface through which the second axis passes is located at the point of the tip end surface that is farthest from the base end of the shaft portion.

[0010] In contrast, when the inner bottom surface is formed of a flat surface, the flat surface is perpendicular to the second axis. When the inner bottom surface is formed of a curved surface, the curved surface is curved spherically so as to bulge toward the opening side.

[0011] Therefore, in the state where the valve body is supported by the housing as described above, the portion of the curved surface of the tip end face through which the second axis passes comes into point contact with the inner bottom surface. The area where the inner bottom surface and the tip surface come into contact (contact area) and the frictional force generated between the inner bottom surface and the tip surface due to the contact are smaller than when the inner bottom surface and the tip surface, each of which is a flat surface, come into surface contact with each other.

[0012] The valve disc is rotated about the first axis relative to the housing against the small frictional force as described above. This rotation changes the state of communication between the inlet and the outlet. [Mode 2] A rotary valve as described in [Mode 1], wherein the tip surface has an annular surface centered on the second axis at a location that is the outer periphery of the curved surface and adjacent to the curved surface, and the annular surface is located farther from the inner bottom surface than the curved surface.

[0013] According to the above configuration, the tip surface includes a curved surface located at a location including the second axis and an annular surface around the curved surface. The annular surface is located farther from the inner bottom surface than the curved surface. Therefore, it is possible to make the shaft portion smaller than when the entire tip surface is composed of a curved surface.

[0014] [Aspect 3] A rotary valve comprising a valve element having a first axis, a housing having a second axis, and a support mechanism for rotatably supporting the valve element on the housing, the housing having an inlet and an outlet for a fluid, the valve element having a valve body portion housed in the housing with the first axis aligned with the second axis, and a communication state of the inlet and the outlet is changed by rotation of the valve element about the first axis, and the support mechanism is provided at one of the housing and the valve body portion. a bearing hole extending in a direction along the second axis, having an opening at one end and an inner bottom surface at the other end, and a shaft portion protruding from the other end in a direction along the second axis and inserted into the bearing hole, the inner bottom surface being formed by a curved surface that is spherically curved so as to bulge toward the opening, a tip surface of the shaft portion, at least a region including the second axis, being formed by a plane perpendicular to the second axis, and the tip surface being in contact with the inner bottom surface at a point on the plane through which the second axis passes.

[0015] According to the above configuration, when the valve body is supported on the housing by the support mechanism, the inner bottom surface of the bearing hole and the tip surface of the shaft portion inserted into the bearing hole come into contact with each other. Here, a plane that constitutes a region of the tip end surface of the shaft portion that includes at least the second axis is perpendicular to the second axis.

[0016] In contrast, the curved surface that constitutes the inner bottom surface is curved spherically so as to bulge towards the opening side. The point of this curved surface through which the second axis passes is located at the point on the inner bottom surface closest to the opening of the bearing hole.

[0017] Therefore, in the state where the valve body is supported by the housing as described above, the portion of the inner bottom surface through which the second axis passes comes into point contact with the flat surface of the tip end surface. The area where the inner bottom surface and the tip surface come into contact (contact area), as well as the frictional force generated between the inner bottom surface and the tip surface due to the contact, are smaller than when the inner bottom surface and the tip surface, each of which is a flat surface, come into surface contact with each other.

[0018] The valve disc is rotated about the first axis relative to the housing against the small frictional force as described above. This rotation changes the state of communication between the inlet and the outlet. [Aspect 4] A rotary valve as described in [Aspect 3], wherein the tip surface has an annular surface centered on the second axis at a location that is the outer periphery of the plane and adjacent to the plane, and the annular surface is located farther from the inner bottom surface than the plane.

[0019] According to the above configuration, the tip surface includes a flat surface located at a location including the second axis and an annular surface around the outer periphery of the flat surface. The annular surface is located farther from the inner bottom surface than the flat surface. Therefore, it is possible to make the shaft portion smaller than when the entire tip surface is composed of a flat surface. Effect of the Invention

[0020] According to the present invention, the rotation torque of the valve body can be reduced. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view of a rotary valve according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional plan view of the rotary valve in the embodiment. [Diagram 3] FIG. 2 is an exploded perspective view of the rotary valve in the embodiment. [Figure 4] FIG. 2 is an exploded perspective view showing a corresponding relationship between a bearing hole of the valve body and a shaft portion of the housing in a state where a part of the housing is cut away in the embodiment. [Diagram 5] 5 is a cross-sectional view taken along line 5-5 of FIG. 2. [Figure 6] FIG. 6 is an enlarged view of part A in FIG. 5. [Figure 7] FIG. 7 is a view corresponding to FIG. 6 and is a partial cross-sectional view showing a modified example of the bearing hole and the shaft portion. [Figure 8] FIG. 7 is a view corresponding to FIG. 6 and is a partial cross-sectional view showing another modified example of the bearing hole and the shaft portion. [Figure 9] FIG. 7 is a view corresponding to FIG. 6 and is a partial cross-sectional view showing another modified example of the bearing hole and the shaft portion. [Figure 10] FIG. 7 is a view corresponding to FIG. 6 and is a partial cross-sectional view showing another modified example of the bearing hole and the shaft portion. [Figure 11] FIG. 7 is a view corresponding to FIG. 6 and is a partial cross-sectional view showing another modified example of the bearing hole and the shaft portion. [Figure 12] 11A and 11B are cross-sectional views showing modified examples of movable flow paths in the valve body. [Figure 13] 13 is a cross-sectional view showing another modified example of the movable flow passage in the valve body. FIG. [Figure 14] 13A and 13B are schematic diagrams showing modified examples of the arrangement of the packing. [Figure 15] FIG. 13 is a schematic diagram showing another modified example of the arrangement of the packing. [Figure 16] FIG. 13 is a schematic diagram showing another modified example of the arrangement of the packing. [Figure 17] FIG. 1 is a side cross-sectional view of a conventional rotary valve. [Figure 18] FIG. 18 is an enlarged view of part B in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a specific embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1, 2 and 5, the rotary valve 10 is provided in a flow path 11 for a fluid FL such as water supplied from a fluid supply source such as a pump (not shown). The rotary valve 10 includes a housing 12, a valve body 31, a support mechanism M1, an actuator 71 and a packing 73. Next, each of the components will be described.

[0023] Here, in order to specify the positional relationship of each part of the rotary valve 10, the first axis AL1 of the valve disc 31 and the second axis AL2 of the housing 12 are used as references. When the valve disc 31 is assembled into the housing 12, the first axis AL1 and the second axis AL2 coincide with each other. The direction along the coincident first axis AL1 and second axis AL2 is referred to as the "axial direction." The radial direction about the coincident first axis AL1 and second axis AL2 is referred to as the "radial direction." The rotational direction of the valve disc 31 about the coincident first axis AL1 and second axis AL2 is referred to as the "circumferential direction."

[0024] <Housing 12> The housing 12 includes a body 13 and a cover 27 . As shown in Figures 1, 3 and 5, the body 13 has a cylindrical storage wall 14 extending in the axial direction. An inner peripheral surface 15 of the storage wall 14 is formed by a cylindrical surface centered on the second axis AL2. A blocking portion 16 is formed at the end of the storage wall 14 opposite the cover 27 in the axial direction (the lower side in Figure 5) with the end closed. The end of the storage wall 14 opposite the blocking portion 16 in the axial direction is an open end 17 that is open. The open end 17 is blocked by the cover 27 attached to the body 13.

[0025] 2 and 5, an inlet 18 for the fluid FL is formed in the storage wall 14. In addition, an outlet 22 for the fluid FL is formed in the storage wall 14 at a location circumferentially spaced from the inlet 18. In this embodiment, the inlet 18 and the outlet 22 each have a circular shape, but may have another shape, such as an ellipse or a polygon.

[0026] The outlet 22 is formed at a location on the opposite side of the inlet 18 across the second axis AL2, or in other words, at a location spaced apart in the circumferential direction from a location facing the inlet 18 across the second axis AL2. In this embodiment, the angle between the central axis of the inlet 18 and the central axis of the outlet 22 is set to about 90°. The inlet 18 and the outlet 22 are not formed at equal angles in the circumferential direction.

[0027] 1, 2, and 5, a connecting pipe 19 is provided on the periphery of the inlet 18 on the outer wall surface of the housing wall 14. The connecting pipe 19 protrudes radially outward from the housing wall 14. The connecting pipe 19 and the fluid supply source are connected by a pipe 21 having a part of the flow path 11 of the fluid FL. The fluid FL supplied from the fluid supply source is guided to the rotary valve 10 by the pipe 21.

[0028] A connecting pipe 23 is provided on the periphery of the outlet 22 on the outer wall surface of the housing wall 14. The connecting pipe 23 protrudes radially outward from the housing wall 14 in a direction different from the protruding direction of the connecting pipe 19. A pipe 24 having a part of the flow path 11 of the fluid FL is connected to the connecting pipe 23. The fluid FL flowing out from the outlet 22 is sent through the pipe 24 to a destination where the fluid FL is used.

[0029] As shown in FIGS. 2, 3 and 5, packing mounting portions 25 are formed around the inlet 18 and around the outlet 22 on the inner side of the housing wall portion 14 in the radial direction.

[0030] <Valve body 31> The valve body 31 has a cylindrical valve body 32 extending in the axial direction. The valve body 32 is accommodated in the accommodation wall 14 with the first axis AL1 coinciding with the second axis AL2. The valve body 32 has an outer circumferential surface 33 facing the inner circumferential surface 15 of the accommodation wall 14. The outer circumferential surface 33 is formed of a cylindrical surface centered on the first axis AL1.

[0031] The valve body 32 has one movable flow path 34 through which the fluid FL flows. In this embodiment, the movable flow path 34 includes a linear first flow path portion 34a and a linear second flow path portion 34b. The first flow path portion 34a and the second flow path portion 34b are connected on the first axis AL1 or in the vicinity of the first axis AL1. The angle α between the first flow path portion 34a and the second flow path portion 34b is set to 90° or a value close to 90°. The movable flow path 34 has a curved shape.

[0032] Of the first flow path portion 34a in the movable flow path 34, an upstream end 35 in the flow direction of the fluid FL opens at the outer circumferential surface 33 of the valve body 32. Of the second flow path portion 34b in the movable flow path 34, a downstream end 36 in the flow direction opens at a position on the outer circumferential surface 33 where the downstream end 36 faces the outlet 22 when the upstream end 35 faces the inlet 18. In this embodiment, the downstream end 36 opens at a position on the outer circumferential surface 33 that is spaced from the upstream end 35 in the circumferential direction.

[0033] The outer diameter of the valve body 32 is set to a value that enables sealing between the accommodating wall 14 and the valve body 32 around the inlet 18 and the outlet 22 by elastically deforming the gasket 73, which will be described later, in the radial direction.

[0034] <Support mechanism M1> 3 and 5, the support mechanism M1 is a mechanism for rotatably supporting the valve body 31 with respect to the housing 12. The support mechanism M1 includes a first support mechanism portion 40 and a second support mechanism portion 50.

[0035] The first support mechanism 40 is provided on the valve body 31 and the cover 27. More specifically, a bearing hole 41 is formed in the center of the cover 27, penetrating the cover 27 in the axial direction. A cylindrical pressing portion 42 is formed on the surface of the cover 27 facing the body 13, around the bearing hole 41. The valve body 31 includes a shaft portion 43 that protrudes in the axial direction from the center of the end surface of the valve main body 32 facing the cover 27. The shaft portion 43 is rotatably inserted through the bearing hole 41. The pressing portion 42 is located around the shaft portion 43, and is in contact with the end surface of the valve main body 32 facing the cover 27. The first support mechanism 40 is configured by the bearing hole 41, the pressing portion 42, and the shaft portion 43.

[0036] 4 to 6, the second support mechanism 50 includes a bottomed bearing hole 51 extending axially in the valve body 32, and a shaft portion 61 provided in the closure portion 16. The bearing hole 51 has an opening 54 at one end in the axial direction, and an inner bottom surface 55 at the other end.

[0037] 4 and 6, bearing hole 51 includes tapered hole portion 52 and main body hole portion 53. Tapered hole portion 52 is formed in a region of bearing hole 51 from a middle portion in the axial direction to opening portion 54. Tapered hole portion 52 is inclined with respect to first axis AL1 so that the diameter increases with increasing distance from inner bottom surface 55.

[0038] Body hole portion 53 is a portion that is rotatably supported by body shaft portion 63 of shaft portion 61. Body hole portion 53 is formed in the region of bearing hole 51 from the intermediate portion to inner bottom surface 55. Body hole portion 53 is circular at any point in the axial direction, and is formed so that the hole diameter is uniform in the axial direction.

[0039] The shaft portion 61 protrudes from the center of the blocking portion 16 toward the inner bottom surface 55 in the axial direction. The shaft portion 61 includes a tapered portion 62 and a main shaft portion 63. The tapered portion 62 is formed in a region of the shaft portion 61 from the middle portion in the axial direction to the base end side (the blocking portion 16 side). The tapered portion 62 is formed at a location that does not interfere with the tapered hole portion 52 when the tip surface 64 of the shaft portion 61 is in contact with the inner bottom surface 55 of the bearing hole 51. The tapered portion 62 is inclined with respect to the second axis AL2 so that the diameter of the tapered portion 62 increases as it moves away from the tip surface 64 of the shaft portion 61. The angle at which the tapered portion 62 is inclined with respect to the second axis AL2 is set to a value that does not interfere with the tapered hole portion 52. In this embodiment, the angle at which the tapered portion 62 is inclined with respect to the second axis AL2 is set to be approximately the same as the angle at which the tapered hole portion 52 is inclined with respect to the first axis AL1, but is not limited thereto.

[0040] The main body shaft portion 63 constitutes the region of the shaft portion 61 from the intermediate portion to the tip side in the axial direction. The main body shaft portion 63 is formed in a cylindrical shape with a diameter slightly smaller than the hole diameter of the main body hole portion 53 and a uniform diameter at any point in the axial direction. A tip surface 64 of the main body shaft portion 63 faces the inner bottom surface 55.

[0041] With the tip surface 64 in contact with the inner bottom surface 55, a large portion of the main body shaft portion 63 is inserted into the main body hole portion 53, and a large portion of the tapered portion 62 is inserted into the tapered hole portion 52.

[0042] In this embodiment, the inner bottom surface 55 of the bearing hole 51 is formed by a plane 56 perpendicular to the first axis AL1. Furthermore, of the tip surface 64 of the shaft portion 61, a region including at least the second axis AL2 is formed by a curved surface 65 that is curved spherically so as to bulge toward the inner bottom surface 55. In this embodiment, the entire tip surface 64 is formed by the curved surface 65. The tip surface 64 is in contact with the inner bottom surface 55 (plane 56) at a portion of the curved surface 65 through which the second axis AL2 passes.

[0043] <Actuator 71> 1 and 3, the actuator 71 rotates the valve body 31 about the first axis AL1 to change the rotational phase. The actuator 71 is, for example, an electric motor. An output shaft (not shown) of the actuator 71 is connected to the shaft portion 43 so as to be rotatable integrally therewith.

[0044] <Packing 73> The packings 73 are used in the same number as the packing attachment portions 25. All of the packings 73 are formed of an elastic material such as rubber. Note that the number of packings 73 used may be less than the number of the packing attachment portions 25.

[0045] 2, 3 and 5, each packing 73 is attached to the packing attachment portion 25. Each packing 73 is located between the peripheral portion of the inlet 18 or the peripheral portion of the outlet 22 on the inner peripheral surface 15 of the housing wall 14 and the outer peripheral surface 33 of the valve body 32. Each packing 73 has a through hole 74 having a shape corresponding to the inlet 18 and the outlet 22, which is circular in this embodiment.

[0046] Next, the operation of the present embodiment configured as above will be described. <Assembly of the valve body 31> When assembling the valve body 31, each packing 73 shown in Fig. 3 is attached to the corresponding packing attachment portion 25. Next, the body 13 and the valve body 31 are moved relative to each other in the axial direction so that the bearing hole 51 and the shaft portion 61 shown in Fig. 4 approach each other in the axial direction, whereby the valve main body portion 32 is inserted into the accommodation wall portion 14.

[0047] As described above, in the rotary valve 10, sealing is performed by elastically deforming each packing 73 outward in the radial direction. Therefore, when the valve body 32 is inserted as described above, a load acts on the valve body 32 in the radially inward direction from each packing 73. In this embodiment in which multiple packings 73 are used, the direction of the load differs for each packing 73.

[0048] On the other hand, in this embodiment, the multiple (pair of) packings 73 are not arranged at equal angles in the circumferential direction. In other words, the pair of packings 73 are not arranged at positions facing each other across the second axis AL2. Therefore, the valve main body 32 receives an offset load from the packings 73. The offset load is a load that is a combination of the loads of the packings 73 and occurs only in a specific direction on the valve main body 32. In this embodiment, as shown by the arrow X in FIG. 2, an offset load acting diagonally upward to the right in FIG. 2 acts on the valve main body 32.

[0049] Furthermore, due to the above-mentioned unbalanced load acting on the valve main body 32, the first axis AL1 of the valve body 31 becomes radially shifted relative to the second axis AL2 of the housing 12 while the valve main body 32 is being inserted into the accommodating wall portion 14.

[0050] In this regard, in the present embodiment, in the process of inserting the valve main body 32 into the housing wall 14, the main body shaft portion 63 of the shaft portion 61 enters the tapered hole portion 52 of the bearing hole 51. Here, the boundary portion between the tip surface 64 of the shaft portion 61 and the outer circumferential surface of the main body shaft portion 63 is defined as a corner portion 66. Then, although not shown, the tapered hole portion 52 abuts against the corner portion 66 (see FIG. 6).

[0051] The tapered hole portion 52 is inclined with respect to the first axis AL1 and the second axis AL2 so that the diameter increases with increasing distance from the inner bottom surface 55. Therefore, as the relative movement for the approaching continues, a force opposing the unbalanced load is applied from the valve body portion 32 to the packings 73. This force causes the valve body portion 32 to push each packing 73 radially outward and is further inserted into the housing wall portion 14. The valve body portion 32 slides (slides) along the tapered hole portion 52, thereby moving in the axial direction while moving in the radial direction. The portion of the tapered hole portion 52 that contacts the corner portion 66 approaches the main body hole portion 53. The first axis AL1 approaches the second axis AL2.

[0052] When the portion of the bearing hole 51 that contacts the corner portion 66 passes through the tapered hole portion 52, the first axis AL1 coincides or approximately coincides with the second axis AL2. Therefore, as the relative movement for the approaching continues, the valve body 32 pushes in the packing 73, and as shown in Fig. 6, the body shaft 63 is inserted into the body hole 53 and the tapered portion 62 is inserted into the tapered hole 52. Then, when the inner bottom surface 55 of the bearing hole 51 comes into contact with the tip surface 64 of the shaft 61, the relative movement for the approaching is stopped.

[0053] In this way, by inserting the valve body 32 into the housing wall 14, the action of the tapered hole 52 guides the shaft 61 into the bearing hole 51 and inserts it there. Therefore, it is not necessary to apply a force to the valve element 31 that counters the unbalanced load so that the first axis AL1 coincides with the second axis AL2 before the shaft 61 is inserted into the bearing hole 51. By simply inserting the valve body 32 into the housing wall 14, it is possible to insert the shaft 61 into the bearing hole 51 while pushing the packing 73 outward in the radial direction. This improves the ease of assembly of the valve element 31.

[0054] <Operation of rotary valve 10> When the rotary valve 10 is operated, the valve body 31 is rotated by the actuator 71 about the first axis AL1.

[0055] 2 and 5 show the state of the rotary valve 10 when the entire upstream end 35 of the movable flow passage 34 faces the entire inlet 18, and the entire downstream end 36 of the movable flow passage 34 faces the entire outlet 22, due to the above rotation. In this state, the entire upstream end 35 and the entire inlet 18 overlap in the circumferential direction, and the entire downstream end 36 and the entire outlet 22 overlap in the circumferential direction. Therefore, the fluid FL flowing through the part of the flow passage 11 upstream of the rotary valve 10 flows into the housing wall 14 through the inlet 18. After flowing through the movable flow passage 34, the fluid FL passes through the outlet 22 and is discharged to the part of the flow passage 11 downstream of the rotary valve 10. In this way, the fluid FL passes through the rotary valve 10. The amount of the fluid FL flowing through the rotary valve 10 is maximum.

[0056] When, from the above state, the above rotation of the valve body 31 causes a part of the upstream end 35 to overlap a part of the inlet 18 in the circumferential direction and a part of the downstream end 36 to overlap a part of the outlet 22 in the circumferential direction, the amount of fluid FL flowing through the rotary valve 10 becomes less than the above maximum amount. Therefore, the amount of fluid FL passing through the rotary valve 10 can be changed by adjusting the rotation amount (rotation phase) of the valve body 31 and adjusting the opening degree (degree of opening) of each of the inlet 18 and the outlet 22.

[0057] Although not shown, when the above-mentioned rotation of the valve body 31 causes the upstream end 35 to no longer face the inlet 18 and the downstream end 36 to no longer face the outlet 22, the flow of the fluid FL is blocked by the rotary valve 10.

[0058] At this time, the gap between the inner circumferential surface 15 of the housing wall 14 and the outer circumferential surface 33 of the valve body 32 is sealed by the packing 73 around the inlet 18 and the outlet 22. The movement of the fluid FL between the outer region and the inner region of the packing 73 is restricted.

[0059] Incidentally, when the valve body 31 is supported on the housing 12 by the support mechanism M1, the inner bottom surface 55 of the bearing hole 51 and the tip surface 64 of the shaft portion 61 come into contact with each other, as shown in FIG. Here, of the tip surface 64, a curved surface 65 constituting an area including at least the second axis AL2 is curved spherically so as to bulge toward the inner bottom surface 55. The portion of this curved surface 65 through which the second axis AL2 passes is located at a portion of the tip surface 64 that is farthest from the base end of the shaft portion 61. In contrast, the inner bottom surface 55 of the bearing hole 51 is formed by a flat surface 56. This flat surface 56 is perpendicular to the first axis AL1 and the second axis AL2.

[0060] Therefore, when the valve body 31 is supported by the housing 12 as described above, the portion of the tip surface 64 through which the second axis AL2 passes is in point contact with the portion of the inner bottom surface 55 through which the first axis AL1 and the second axis AL2 pass.

[0061] The area (contact area) of the contact between the inner bottom surface 55 and the tip surface 64, and the frictional force generated between the inner bottom surface 55 and the tip surface 64 due to the contact, are smaller than those of the conventional rotary valve 100 in which the inner bottom surface 109 and the tip surface 112 come into surface contact. The valve body 31 of this embodiment is rotated about the first axis AL1 relative to the housing 12 against the small frictional force as described above. This rotation changes the communication state between the inlet 18 and the outlet 22 as described above.

[0062] Next, the effects of this embodiment will be described. (1) As shown in FIG. 6, in this embodiment, as the second support mechanism part 50 in the support mechanism M1, a bearing hole 51 is provided in the valve body part 32, and a shaft part 61 is protruded from the closed part 16 of the housing 12. The inner bottom surface 55 of the bearing hole 51 is formed by a plane 56 perpendicular to the first axis AL1 and the second axis AL2. The entire tip surface 64 of the shaft part 61 is formed by a curved surface 65 that is curved spherically so as to bulge toward the inner bottom surface 55 side. The tip surface 64 is in point contact with the inner bottom surface 55 at a portion of the curved surface 65 through which the second axis AL2 passes. Therefore, the frictional force generated between the tip surface 64 and the inner bottom surface 55 can be reduced, and the rotational torque required to rotate the valve body 31 can be reduced compared to the conventional rotary valve 100.

[0063] As a result, it is possible to reduce the load applied to the mechanism for rotating the valve body 31. This makes it possible to extend the product life of the rotary valve 10. Also, it is possible to reduce the size of the actuator 71.

[0064] (2) The above-mentioned effect (1) can be obtained simply by changing the tip surface 112 of the shaft portion 111 in the conventional rotary valve 100 from a flat surface perpendicular to the second axis AL2 to a spherically curved surface 65.

[0065] (3) It is also possible to make point contact with the inner bottom surface 55 by making at least the area of ​​the tip surface 64 of the shaft portion 61 that includes the second axis AL2 protrude toward the inner bottom surface 55 and make the tip pointed.

[0066] In this case, however, the strength of the sharp tip portion of shaft portion 61 and the surrounding area is low and there is a risk of breakage. In this regard, if the tip surface 64 is configured as a curved surface 65 that is spherically curved so as to bulge toward the inner bottom surface 55, as in the above embodiment, the strength of the tip portion of the shaft portion 61 can be increased, making it less likely to break.

[0067] 5 and 6, in this embodiment, a tapered portion 62 that is inclined with respect to the second axis AL2 is formed in a region of the shaft portion 61 from a middle portion in the axial direction to the base end portion so that the diameter of the shaft portion 61 increases toward the base end portion, thereby increasing the strength of the shaft portion 61 compared to a case in which the tapered portion 62 is not provided.

[0068] The above embodiment can also be implemented as modified examples as follows: The above embodiment and the following modified examples can be implemented in combination with each other within a range that does not cause technical contradiction.

[0069] <Matters regarding Housing 12> The housing 12 may be provided with one inlet 18 and a plurality of outlets 22. In this case, the outlet 22 that is connected to the inlet 18 may be switched by rotating the valve body 31.

[0070] Alternatively, a plurality of inlets 18 may be provided, and one outlet 22 may be provided. In this case, the inlet 18 that is in communication with the outlet 22 may be switched by rotating the valve body 31. Furthermore, a plurality of inlets 18 and a plurality of outlets 22 may be provided in the housing 12. In this case, the outlets 22 communicating with the respective inlets 18 may be switched by rotating the valve body 31.

[0071] <Matters Concerning the Inner Bottom Surface 55 of the Bearing Hole 51 and the Tip Surface 64 of the Shaft Portion 61> The relationship between the flat surface 56 and the curved surface 65 may be changed to be the opposite of that in the above embodiment. That is, as shown in Fig. 7, the entire inner bottom surface 55 may be formed by the curved surface 58, and the entire tip surface 64 may be formed by the flat surface 69.

[0072] Here, the flat surface 69 constituting the tip surface 64 is perpendicular to the second axis AL2. In contrast, the curved surface 58 constituting the inner bottom surface 55 is curved spherically so as to bulge toward the opening 54. The point of this curved surface 58 through which the first axis AL1 and the second axis AL2 pass is located at the point of the inner bottom surface 55 closest to the opening 54.

[0073] Therefore, when the valve body 31 is supported by the housing 12, the portion of the flat surface 69 of the tip face 64 through which the second axis AL2 passes comes into point contact with the portion of the inner bottom face 55 through which the first axis AL1 and the second axis AL2 pass.

[0074] The area (contact area) where the inner bottom surface 55 and the tip surface 64 come into contact, as well as the frictional force generated between the inner bottom surface 55 and the tip surface 64 due to the contact, are smaller than those of the conventional rotary valve 100 in which the inner bottom surface 109 and the tip surface 112 come into surface contact.

[0075] As described above, the valve body 31 is rotated about the first axis AL1 relative to the housing 12 against the small frictional force. Due to this rotation, the communication state between the inlet 18 and the outlet 22 is changed.

[0076] As a result, the modification of FIG. 7 can also obtain the same effect as that of (1) above, that is, the rotational torque required to rotate the valve body 31 is reduced. Both the inner bottom surface 55 and the tip surface 64 may be formed of curved surfaces. That is, as shown in Fig. 8, the entire inner bottom surface 55 may be formed of a curved surface 58 that is curved in a spherical shape so as to bulge towards the opening 54. Also, the entire tip surface 64 may be formed of a curved surface 65 that is curved in a spherical shape so as to bulge towards the inner bottom surface 55.

[0077] Here, the portion of the curved surface 65 through which the second axis AL2 passes is located at a portion of the tip surface 64 that is farthest from the base end of the shaft portion 61. In contrast, the portion of the curved surface 58 through which the first axis AL1 and the second axis AL2 pass is located at a portion of the inner bottom surface 55 that is closest to the opening 54.

[0078] Therefore, when the valve body 31 is supported by the housing 12, a portion of the tip face 64 through which the second axis AL2 passes is in point contact with a portion of the inner bottom face 55 through which the first axis AL1 and the second axis AL2 pass.

[0079] The area (contact area) where the inner bottom surface 55 and the tip surface 64 come into contact, as well as the frictional force generated between the inner bottom surface 55 and the tip surface 64 due to the contact, are smaller than those of the conventional rotary valve 100 in which the inner bottom surface 109 and the tip surface 112 come into surface contact.

[0080] As described above, the valve body 31 is rotated about the first axis AL1 relative to the housing 12 against the small frictional force. Due to this rotation, the communication state between the inlet 18 and the outlet 22 is changed.

[0081] As a result, the modification of FIG. 8 can also obtain the same effect as that of (1) above, that is, the rotational torque required to rotate the valve body 31 is reduced. <Matters regarding tip surface 64> In the above embodiment (see FIG. 6) and the modified example of FIG. 8, the curved surface 65 need only constitute a region of the tip surface 64 that includes at least the second axis AL2, and does not necessarily have to constitute the entire region of the tip surface 64. FIG. 9 and FIG. 11 show one example. In these modified examples, the region of the shaft portion 61 from the middle portion to the tip side in the axial direction is constituted by a tapered shaft portion 67.

[0082] The area of ​​the tip surface 64 including the second axis AL2 is formed by the curved surface 65. The outer peripheral portion of the tip surface 64, i.e., the outer periphery of the curved surface 65 and adjacent to the curved surface 65, is formed by a tapered annular surface 68 centered on the second axis AL2. The annular surface 68 is inclined with respect to the second axis AL2 so that the diameter decreases with increasing distance from the base end of the shaft portion 61. Therefore, the annular surface 68 is located at a location farther from the inner bottom surface 55 than the curved surface 65. The curved surface 65 in the modification of Figs. 9 and 11 is smaller than the curved surface 65 in the embodiment and the modification of Fig. 8 due to the formation of the annular surface 68.

[0083] The modified example in FIG. 9 and the modified example in FIG. 11 differ in the following respects. In the modification shown in Fig. 9, the entire inner bottom surface 55 is formed of a flat surface 56 perpendicular to the first axis AL1 and the second axis AL2, similar to the above embodiment (see Fig. 6). In contrast, in the modification shown in Fig. 11, the entire inner bottom surface 55 is formed of a curved surface 58 that is curved spherically so as to bulge toward the opening 54, similar to the modification shown in Fig. 8.

[0084] 9 and 11, it is possible to reduce the size of the shaft portion 61 compared to the embodiment (see FIG. 6) and the modification of FIG. 8 in which the entire tip surface 64 is configured by the curved surface 65 that bulges toward the inner bottom surface 55. Note that it is only the curved surface 65 that is involved in contact with the inner bottom surface 55 in the tip surface 64. Therefore, as described above, there is no problem even if the annular surface 68 is located at a location farther from the inner bottom surface 55 than the curved surface 65.

[0085] In the modified example of FIG. 9 and FIG. 11, the tapered hole portion 52 is omitted from the bearing hole 51, and the tapered portion 62 is omitted from the shaft portion 61. In the modification shown in Fig. 7 above, the plane 69 need only constitute a region of the tip surface 64 that includes at least the second axis AL2, and does not necessarily have to constitute the entire region of the tip surface 64. Fig. 10 shows one such example. In this modification, like the modifications shown in Figs. 9 and 11 above, the region of the shaft portion 61 from the middle portion to the tip side in the axial direction is constituted by a tapered shaft portion 67.

[0086] The area of ​​the tip surface 64 including the second axis AL2 is formed by a plane 69 similar to that in FIG. 7. The outer peripheral portion of the tip surface 64, i.e., the outer periphery of the plane 69 and adjacent to the plane 69, is formed by a tapered annular surface 68 centered on the second axis AL2. The annular surface 68 is inclined with respect to the second axis AL2 so that the diameter decreases with increasing distance from the base end of the shaft portion 61. Therefore, the annular surface 68 is located at a position farther from the inner bottom surface 55 than the plane 69. The plane 69 in the modification in FIG. 10 is smaller than the plane 69 in the modification in FIG. 7 due to the formation of the annular surface 68.

[0087] 10, it is possible to make the shaft portion 61 smaller than in the modification of FIG. 7 in which the entire tip surface 64 is formed by a plane 69 perpendicular to the second axis AL2. It is only the plane 69 that is involved in contact with the inner bottom surface 55 on the tip surface 64. Therefore, there is no problem even if the annular surface 68 is located at a position farther from the inner bottom surface 55 than the plane 69 is, as described above.

[0088] 9 and 11, in the modification example of FIG. 10, the tapered hole portion 52 is omitted from the bearing hole 51, and the tapered portion 62 is omitted from the shaft portion 61. Incidentally, the tapered annular surface 68 in the modified example of FIGS. 9 to 11 exerts a function similar to that of the tapered hole portion 52 in the above embodiment and the modified examples of FIGS.

[0089] That is, when assembling the valve body 31, the packings 73 are attached to the packing attachment portions 25 in the same manner as in the above embodiment. Next, the body 13 and the valve body 31 are moved relative to each other in the axial direction so that the bearing hole 51 and the shaft portion 61 approach each other in the axial direction, thereby inserting the valve main body 32 into the housing wall portion 14. During this insertion, an offset load acts on the valve main body 32 from the packings 73 in the same manner as in the above embodiment. Due to this offset load, the first axis AL1 becomes misaligned in the radial direction with respect to the second axis AL2 during the above insertion.

[0090] Here, the boundary portion between the inner peripheral surface of the bearing hole 51 and the open surface of the bearing hole 51 in the valve body 32, i.e., the surface of the valve body 32 on the closed section 16 side, is defined as a corner 57. Then, in the modified example of Figs. 9 to 11, although not shown, the corner 57 (see Figs. 9 to 11) comes into contact with the annular surface 68 of the tapered shaft portion 67 during the insertion process. The annular surface 68 is inclined with respect to the second axis AL2 so that the diameter decreases as it moves away from the base end of the shaft portion 61. Therefore, when the relative movement for the approach is continued, a force opposing the unbalanced load is applied from the valve body 32 to the packing 73. Due to this force, the valve body 32 is further inserted into the housing wall portion 14 while pushing each packing 73 outward in the radial direction. The valve body 32 slides (slides) along the annular surface 68, thereby moving in the radial direction and in the axial direction. The portion of the annular surface 68 with which the corner portion 57 comes into contact approaches the outer circumferential surface of the shaft portion 61. When the portion of the corner portion 57 that comes into contact with the shaft portion 61 passes through the annular surface 68, the first axis AL1 coincides or approximately coincides with the second axis AL2.

[0091] Therefore, as the relative movement for the approaching continues, the valve body 32 pushes the packing 73 radially outward, while a large portion of the shaft portion 61 is inserted into the bearing hole 51. Then, when the inner bottom surface 55 of the bearing hole 51 comes into contact with the tip surface 64 of the shaft portion 61, the relative movement for the approaching is stopped.

[0092] In this way, by inserting the valve body 32 into the housing wall 14, the shaft 61 is guided and inserted into the bearing hole 51 by the action of the annular surface 68. Therefore, it is not necessary to apply a force to the valve element 31 against the unbalanced load so that the first axis AL1 coincides with the second axis AL2 before the shaft 61 is inserted into the bearing hole 51. As in the above embodiment, by simply inserting the valve body 32 into the housing wall 14, it is possible to insert the shaft 61 into the bearing hole 51 while pushing the packing 73 outward in the radial direction. This improves the ease of assembly of the valve element 31.

[0093] <Matters related to valve body 31> The valve body 32 may be formed in a spherical shape instead of a cylindrical shape. In this case, the shape of the inner surface of the housing wall 14 is also changed according to the change in the shape of the valve body 32.

[0094] In this modification, it is also possible to provide a bearing hole 51 on one of the valve body 32 and the housing 12, and provide a shaft portion 61 on the other. In this case, the shape of the inner bottom surface 55 and the shape of the tip surface 64 may be the same as those of the embodiment described above and the modification shown in Figs. 7 to 11.

[0095] In this way, although the outer shape of the valve body 32 and the inner shape of the housing wall 14 differ from those of the above embodiment, the tip surface 64 and the inner bottom surface 55 are in point contact with each other, similar to the above embodiment. Therefore, similar to the above embodiment, the effect of reducing frictional force and reducing the rotational torque of the valve body 31 can be obtained.

[0096] The valve body 31 may be rotated by an actuator 71 of a type different from a motor. Also, instead of using the actuator 71, the valve body 31 may be rotated by manual operation. The shape of the movable flow path 34 in the valve body 31 may be modified to a shape different from that of the above embodiment. Fig. 12 shows one modified example. In this modified example, the angle α between the first flow path portion 34a and the second flow path portion 34b is set to a value greater than 90°. Although not shown, the angle α may be set to a value less than 90°. The dashed line in Fig. 12 indicates the central axis of the movable flow path 34.

[0097] Although not shown, the movable flow passage 34 may be formed of a single straight flow passage without bending. The number of movable flow paths in the valve body 31 may be changed to two or more. FIG. 13 shows a modified example in which two movable flow paths are provided in the valve body 31. In this modified example, the movable flow path includes a movable flow path 34 bent as in the above embodiment, and a movable flow path 37 formed at a location separated from the movable flow path 34. The same fluid as the fluid FL flowing through the movable flow path 34 may flow through the movable flow path 37, or a different fluid may flow through the movable flow path 37. In the modified example, the movable flow path 37 includes a linear first flow path portion 37a and a linear second flow path portion 37b. The first flow path portion 37a and the second flow path portion 37b are connected. In FIG. 13, the angle β between the first flow path portion 37a and the second flow path portion 37b is set to a value smaller than 90°, but may be set to a value equal to or larger than 90°. The dashed line in FIG. 13 indicates the central axis of the movable flow paths 34 and 37.

[0098] Of the first flow path portion 37a, an upstream end in the fluid flow direction opens at the outer circumferential surface 33 of the valve body 32. Of the second flow path portion 37b, a downstream end in the fluid flow direction opens at the outer circumferential surface 33 at a location spaced from the upstream end in the circumferential direction of the accommodation wall 14.

[0099] The movable flow path 37 may be formed of a single straight flow path without bending. <Matters concerning the placement of packing 73> An example of a case in which the valve body 32 receives an unbalanced load from the packing 73 is a case in which the multiple packings 73 are not arranged at equal angles in the circumferential direction as in the above embodiment.

[0100] Fig. 14 shows an example of a modification in which the three packings 73a, 73b, and 73c are not arranged at equal angles. Here, the central axis of the through hole of packing 73a is CL1, the central axis of the through hole of packing 73b is CL2, and the central axis of the through hole of packing 73c is CL3. In Fig. 14, the valve body 32 of the valve body 31 is shown by a two-dot chain line. This also applies to Figs. 15 and 16 described later.

[0101] In the modification shown in FIG. 14, two packings 73a, 73c are disposed at positions opposite to each other across the first axis AL1 and the second axis AL2. The angle θ31 between the central axis CL3 and the central axis CL1 is set to 180°. The remaining packing 73b is disposed at a position midway between the two packings 73a, 73c in the circumferential direction. The angle θ12 between the central axis CL1 and the central axis CL2 is set to 90°. The angle θ23 between the central axis CL2 and the central axis CL3 is set to 90°.

[0102] Even in this modification, the valve body 32 receives an unbalanced load. Also in this modification, the above-mentioned effect of reducing the rotational torque of the valve element 31 can be obtained. The present invention is also applicable to a case where the valve body 32 is not subjected to an offset load from the packing 73.

[0103] An example of a case where the packing is not subjected to an unbalanced load is a case where another packing is disposed on the opposite side of the packing across the first axis AL1 and the second axis AL2. In other words, a pair of packings is disposed opposite each other across the first axis AL1 and the second axis AL2. In this case, the two packings disposed opposite each other may be one set or multiple sets.

[0104] 15 shows a modified example in which there are two pairs of opposing packings. Packing 73a and packing 73c are arranged to face each other across the first axis AL1 and the second axis AL2. Packing 73b and packing 73d are arranged to face each other across the first axis AL1 and the second axis AL2.

[0105] Here, the central axes of the through holes of the packings 73a, 73b, and 73c are designated CL1, CL2, and CL3, respectively, similarly to the modification in Fig. 14. Furthermore, the central axis of the through hole of the packing 73d is designated CL4.

[0106] In this modified example, the angle θ12 between the central axis CL1 and the central axis CL2 is set to 60°. The angle θ23 between the central axis CL2 and the central axis CL3 is set to 120°. The angle θ34 between the central axis CL3 and the central axis CL4 is set to 60°. The angle θ41 between the central axis CL4 and the central axis CL1 is set to 120°.

[0107] The angle between the central axis CL1 and the central axis CL3 is set to 180°, and the angle between the central axis CL2 and the central axis CL4 is set to 180°. As another example of a case where no unbalanced load is applied, a plurality of packings 73 are arranged at equal angles in the circumferential direction.

[0108] FIG. 16 shows a modified example in which three packings 73a, 73b, and 73c are arranged at equal angles. Here, the central axes of the through holes of the packings 73a, 73b, and 73c are designated CL1, CL2, and CL3, respectively, as in the modified example of Fig. 14. The angle θ12 between the central axis CL1 and the central axis CL2, the angle θ23 between the central axis CL2 and the central axis CL3, and the angle θ31 between the central axis CL3 and the central axis CL1 are all set to 120°.

[0109] <Other matters> 7 to 11, the housing 12 may be provided with a bearing hole 51, and the valve body 32 may be provided with a shaft portion 61. In this case, the shape of the inner bottom surface 55 and the shape of the tip surface 64 may be the same as those of the embodiment and the modified examples of FIGS.

[0110] In this way, although the objects on which the bearing hole 51 and the shaft portion 61 are formed are different, the point at which the tip surface 64 and the inner bottom surface 55 come into point contact with each other is similar to the above embodiment and the modified examples shown in Figures 7 to 11. Therefore, similar to the above embodiment and the modified examples shown in Figures 7 to 11, the effect of reducing frictional force and reducing the rotational torque of the valve body 31 can be obtained.

[0111] The rotary valve 10 described above can also be applied to a rotary valve provided in a flow path through which a liquid other than water flows as the fluid FL, or to a rotary valve provided in a flow path through which gas flows instead of a liquid as the fluid FL. [Explanation of symbols]

[0112] 10...Rotary valve 12. Housing 18...Inlet 22... Outlet 31...Valve body 32...Valve body 51...Bearing hole 54…Opening 55…Inner bottom surface 56,69…Plane 58,65…Curved surface 61...Shaft 64…Tip surface 68...Ring AL1…1st axis line AL2…Second axis FL…Fluid M1…Support mechanism

Claims

1. a valve body having a first axis, a housing having a second axis, and a support mechanism that rotatably supports the valve body on the housing, the housing has a fluid inlet and a fluid outlet; the valve body has a valve main body portion that is accommodated in the housing with the first axis aligned with the second axis, A rotary valve in which a communication state between the inlet and the outlet is changed by rotation of the valve body about the first axis, the support mechanism includes a bearing hole extending in a direction along the second axis in one of the housing and the valve body, the bearing hole having an opening at one end and an inner bottom surface at the other end, and a shaft portion protruding from the other in a direction along the second axis and inserted into the bearing hole, The inner bottom surface is configured by a plane perpendicular to the second axis or a curved surface curved spherically so as to bulge toward the opening side, Of the tip surface of the shaft portion, at least a region including the second axis is configured by a curved surface that is curved spherically so as to bulge toward the inner bottom surface, The tip surface of the rotary valve is in contact with the inner bottom surface at a location of the curved surface of the tip surface through which the second axis passes.

2. the tip surface has an annular surface that is an outer periphery of the curved surface and is adjacent to the curved surface and has a center on the second axis; 2. The rotary valve according to claim 1, wherein the annular surface is located farther from the inner bottom surface than the curved surface.

3. a valve body having a first axis, a housing having a second axis, and a support mechanism that rotatably supports the valve body on the housing, the housing has a fluid inlet and a fluid outlet; the valve body has a valve main body portion that is accommodated in the housing with the first axis aligned with the second axis, A rotary valve in which a communication state between the inlet and the outlet is changed by rotation of the valve body about the first axis, the support mechanism includes a bearing hole extending in a direction along the second axis in one of the housing and the valve body, the bearing hole having an opening at one end and an inner bottom surface at the other end, and a shaft portion protruding from the other in a direction along the second axis and inserted into the bearing hole, The inner bottom surface is configured by a curved surface that is curved spherically so as to bulge toward the opening side, A region of the tip end surface of the shaft portion that includes at least the second axis is formed by a plane perpendicular to the second axis, The tip surface of the rotary valve is in contact with the inner bottom surface at a location on the plane through which the second axis passes.

4. the tip surface has an annular surface that is an outer periphery of the plane and is adjacent to the plane and is centered on the second axis; 4. The rotary valve according to claim 3, wherein the annular surface is located farther from the inner bottom surface than the flat surface.

Images