Switching valve

Abstract

Provided is a switching valve in which the posture of a valve body can be stabilized.　A valve body 10 has a core 18 formed coaxially with a rotary shaft 18 in a communication groove 17, and the communication groove 17 has a center part 17A surrounding the core 18 and a peripheral part 17C extending from the center part 17A to the outer diameter side.

Description

Switching valve

[0001] The present invention relates to a switching valve, for example, a switching valve that switches a flow path through which a fluid flows.

[0002] In various industrial fields, fluid circuits are used in which a fluid supply source and a fluid load such as a fluid working device or a heat exchanger are connected by a flow path. Some of these fluid circuits are provided with a switching valve that switches the flow path of the working fluid, thereby realizing multiple modes for operating the fluid load using a single fluid circuit.

[0003] For example, the switching valve disclosed in Patent Document 1 includes a housing provided with a plurality of inlet ports and a plurality of outlet ports, and a disk-shaped valve element rotatably disposed on a rotation shaft relative to the housing. The valve element has a plurality of through holes and a groove extending in a planar direction so as to pass through a central axis. By rotating the valve element, it is possible to switch the combination of inlet ports and outlet ports that communicate via the through holes or grooves.

[0004] JP 2019-49364 A (page 13, Figure 6)

[0005] In a switching valve such as that disclosed in Patent Document 1, the groove has a wide variety of shapes, enabling multiple modes of the fluid circuit to be realized. However, depending on the shape of the groove, the fluid flowing through the groove may be biased to one side of the central axis of the valve disc, which may cause the valve disc to tilt relative to the rotation axis and cause rattle of the valve disc.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a switching valve capable of stabilizing the position of the valve body.

[0007] In order to solve the above problems, the switching valve of the present invention is a switching valve including: a housing, a plurality of ports provided in the housing, a valve element having communication grooves communicating between the plurality of ports and rotatably disposed within the housing, and a rotary shaft connected to the valve element and rotating the valve element, wherein the valve element has a core formed in the communication groove coaxially with the rotary shaft, and the communication groove has a center portion surrounding the core and a peripheral portion extending radially outward from the center. In this way, the fluid flowing in the communication groove is divided into two portions flowing on either side of the core, thereby stabilizing the attitude of the valve element.

[0008] The core may be cylindrical or columnar, which allows the fluid to flow smoothly along the core.

[0009] The inner surface of the communication groove may be configured as a curved surface, whereby the fluid is smoothly guided to both sides of the communication groove that sandwich the core.

[0010] The ratio of the cross-sectional areas of the flow channels on both sides of the core in the communicating groove may be less than 2. This can reduce the difference in the influence of the fluid flowing on both sides of the core in the communicating groove.

[0011] The valve element may have through holes formed on both sides of the communicating groove, sandwiching the core, so that when the fluid pressure in the communicating groove becomes excessively high, the fluid can be released evenly to the through holes on both sides, thereby stabilizing the attitude of the valve element.

[0012] The communicating grooves are symmetrical with respect to a line passing through the core in the radial direction, thereby distributing the influence of the fluid flowing through the communicating grooves in a balanced manner.

[0013] The communication grooves may be provided at positions overlapping both sides of the valve body, respectively. In this way, fluid pressure acts on both sides of the valve body in a balanced manner, thereby stabilizing the attitude of the valve body.

[0014] The peripheral portion may extend so as to widen toward the central portion, which allows the fluid to easily flow in two directions across the core.

[0015] 1A and 1B are cross-sectional views showing a switching valve according to a first embodiment of the present invention. 1A is a top view of an upper cover. 1B is a top view of a lower cover. 1C is a top view of an upper stator and a lower stator. 1A is a top view of a valve body, 1B is an A-A cross-sectional view, and 1C is a B-B cross-sectional view. 1A is a schematic diagram showing a first flow path pattern, and 1B is a schematic diagram showing a rotational position of a valve body constituting the first flow path pattern. 1A is a schematic diagram showing a second flow path pattern, and 1B is a schematic diagram showing a rotational position of a valve body constituting the second flow path pattern. 1A is a schematic diagram showing a third flow path pattern, and 1B is a schematic diagram showing a rotational position of a valve body constituting the third flow path pattern. 1A is a schematic diagram showing a fourth flow path pattern, and 1B is a schematic diagram showing a rotational position of a valve body constituting the fourth flow path pattern. 1A is a schematic diagram showing a fifth flow path pattern, and 1B is a schematic diagram showing a rotational position of a valve body constituting the fifth flow path pattern. 1C is a schematic diagram showing a state in which a fluid flows around a core. 1D is a schematic diagram showing a valve body according to a second embodiment of the present invention. 1A to 1C are schematic diagrams showing a first modified example of the valve body, a second modified example of the valve body, and a third modified example of the valve body;

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A switching valve according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0017] A switching valve according to a first embodiment will be described with reference to Fig. 1 to Fig. 11. In the following description, the top and bottom of Fig. 1 will be referred to as the top and bottom of the switching valve. Specifically, the top side of the paper on which the motor is located will be referred to as the top side of the switching valve, and the opposite side, the bottom side of the paper, will be referred to as the bottom side of the switching valve.

[0018] As shown in FIG. 1, the switching valve V is used to select one of a plurality of modes of the fluid circuit and to switch the flow path through which the working fluid flows.

[0019] The switching valve V is mainly composed of a valve body 10 , a housing 50 , and a motor 60 .

[0020] The housing 50 is composed of a cylindrical middle case 51 , a disk-shaped upper cover 52 , a disk-shaped lower cover 53 , a disk-shaped upper stator 54 , and a disk-shaped lower stator 55 .

[0021] The upper cover 52 hermetically closes the upper opening of the middle case 51. The lower cover 53 hermetically closes the lower opening of the middle case 51. The upper stator 54 is disposed between the upper cover 52 and the valve body 10 and functions as a valve seat. The lower stator 55 is disposed between the lower cover 53 and the valve body 10 and functions as a valve seat.

[0022] The middle case 51, the upper cover 52, the lower cover 53, the upper stator 54, and the lower stator 55 are made of a metal material or a resin material.

[0023] As shown in FIG. 2, the top cover 52 is provided with a first port P1, a second port P2, a third port P3, and a fourth port P4 as ports that pass through in the vertical direction.

[0024] A through hole 52a is provided in the center of the top cover 52, and a rotary shaft 61 extending from the motor 60 is rotatably inserted therethrough (see FIG. 1). More specifically, the upper end of the rotary shaft 61 is rotatably supported by a bearing 20 disposed on the inner peripheral surface of the through hole 52a of the top cover 52 (see FIG. 1).

[0025] The first port P1 and the third port P3 function as outlet ports through which the working fluid in the switching valve V flows out to an external fluid load (not shown).

[0026] The second port P2 and the fourth port P4 function as inlet ports through which the working fluid discharged from an external fluid load (not shown) flows into the switching valve V.

[0027] As shown in FIG. 3, the lower cover 53 is provided with a fifth port P5, a sixth port P6, a seventh port P7, and an eighth port P8 that penetrate the lower cover 53 in the vertical direction.

[0028] An upwardly opening recess 53a is provided in the center of the lower cover 53, and the lower end of the rotating shaft 61 is rotatably supported in the recess 53a. More specifically, the lower end of the rotating shaft 61 is rotatably supported by a bearing 21 disposed on the inner peripheral surface of the recess 53a (see FIG. 1).

[0029] The fifth port P5 and the seventh port P7 function as inlet ports through which the working fluid discharged from an external fluid load (not shown) flows into the switching valve V.

[0030] The sixth port P6 and the eighth port P8 function as outlet ports through which the working fluid in the switching valve V flows out to an external fluid load (not shown).

[0031] Next, the upper stator 54 and the lower stator 55 will be described with reference to Figures 1 and 4. Since the upper stator 54 and the lower stator 55 have almost the same shape, the same drawing will be used for the description in Figure 4.

[0032] 1, the upper stator 54 is disposed between the upper cover 52 and the valve body 10 inside the middle case 51. A plurality of coiled wave springs 56 serving as a biasing means are provided between the upper cover 52 and the upper stator 54. The upper stator 54 is biased toward the valve body 10 by the coiled wave springs 56.

[0033] As shown in FIG. 4, the upper stator 54 is provided with through holes 54a, 54b, 54c, and 54d that penetrate in the vertical direction, and a central hole 54e.

[0034] The through hole 54a of the upper stator 54 is sealed and communicates with the first port P1 by an O-ring 22, the through hole 54b is sealed and communicates with the second port P2 by an O-ring 23, the through hole 54c is sealed and communicates with the third port P3 by an O-ring 24, and the through hole 54d is sealed and communicates with the fourth port P4 by an O-ring 25. A rotating shaft 61 is rotatably inserted through the central hole 54e.

[0035] As shown in FIG. 1 , the lower stator 55 is disposed between the lower cover 53 and the valve body 10 inside the intermediate case 51 .

[0036] As shown in FIG. 4, the lower stator 55 is provided with through holes 55a, 55b, 55c, and 55d that penetrate in the vertical direction, and a central hole 55e.

[0037] The through hole 55a of the lower stator 55 is sealed and communicates with the fifth port P5 by an O-ring 22', the through hole 55b is sealed and communicates with the sixth port P6 by an O-ring 23', the through hole 55c is sealed and communicates with the seventh port P7 by an O-ring 24', and the through hole 55d is sealed and communicates with the eighth port P8 by an O-ring 25'. A rotating shaft 61 is rotatably inserted through the central hole 55e.

[0038] Next, the valve body 10 will be described with reference to Fig. 5. Note that in Fig. 5, dots are added for the sake of convenience.

[0039] 5(a) and 5(b), the valve body 10 is disk-shaped and has through holes 11, 12, 13, 14, 15, and 16, communicating grooves 17 and 17′ serving as communicating passages, and cylindrical portions 18 and 18′ serving as cores.

[0040] As shown in Figure 5(a), through-hole 11 is provided at the 3 o'clock position of the valve body 10 when viewed from above. Through-hole 12 is provided at a position between 4 o'clock and 5 o'clock on the valve body 10 when viewed from above. Through-hole 13 is provided at the 6 o'clock position of the valve body 10 when viewed from above. Through-hole 14 is provided at a position between 7 o'clock and 8 o'clock on the valve body 10 when viewed from above. Through-hole 15 is provided at the 9 o'clock position of the valve body 10 when viewed from above. Through-hole 16 is provided at the 12 o'clock position of the valve body 10 when viewed from above.

[0041] The communicating groove 17 is a groove with a concave cross section that opens upward. This communicating groove 17 has a portion (i.e., a central portion 17A) that is provided on the inner diameter side of the through holes 11 to 16 in the valve body 10, and portions (i.e., peripheral portions 17B, 17C) that bulge out at positions between 1 o'clock and 2 o'clock and between 10 o'clock and 11 o'clock on the valve body 10. Note that in Figure 5(a), the central portion 17A and the peripheral portions 17B, 17C are indicated by different dots for ease of explanation.

[0042] The central portion 17A has a generally annular shape in a top view, and the peripheral portions 17B and 17C extend radially outward from the central portion 17A and have a bell shape.

[0043] The volume VL1 of the central portion 17A is larger than the combined volume VL2 of the peripheral portions 17B and 17C (VL1>VL2). Specifically, the volume VL1 is at least five times larger than the volume VL2.

[0044] The inner surfaces of the communicating groove 17, i.e., the inner surface 17a of the central portion 17A, the inner surfaces 17b and 17c of the boundary portions between the central portion 17A and the peripheral portions 17B and 17C, and the inner surface 17d of the boundary portion between the peripheral portions 17B and 17C, are curved surfaces. These inner surfaces form the outer surfaces of the communicating groove 17.

[0045] A cylindrical portion 18 is provided standing up from the bottom surface of the communicating groove 17. The outer surface of the cylindrical portion 18 forms the inner surface of the communicating groove 17.

[0046] 5(a) to 5(c), the cylindrical portion 18 is provided at the center of the valve body 10, and its upper end is located at the same height as the upper surface of the valve body 10. The inner peripheral surface of the cylindrical portion 18 is generally star-shaped polygonal when viewed in the axial direction. A rotation shaft 61 is inserted into and fitted into this cylindrical portion 18. As a result, when the rotation shaft 61 rotates, the valve body 10 can rotate around the rotation shaft 61.

[0047] The communication groove 17 has a shape that is line-symmetrical with respect to an imaginary line α that passes through the center of the cylindrical portion 18 and extends radially from the 12 o'clock position to the 6 o'clock position.

[0048] The communicating groove 17 has a first passage R1 that passes through one side of the cylindrical portion 18 to connect the peripheral portions 17B and 17C, and a second passage R2 that passes through the other side of the cylindrical portion 18 to connect the peripheral portions 17B and 17C.

[0049] 5(b) and 5(c), the cross-sectional area A1 of the first passage R1 (see the shaded area of ​​the small stitches) is substantially constant in the extension direction. The cross-sectional area A2 of the second passage R2 (see the shaded area of ​​the large stitches) is substantially constant in the extension direction. The cross-sectional area A1 of the first passage R1 and the cross-sectional area A2 of the second passage R2 are substantially the same size. The ratio of the cross-sectional area A1 of the first passage R1 to the cross-sectional area A2 of the second passage R2 may be less than two times either of them.

[0050] 5(b) and 5(c), the communication groove 17' is a groove that is provided on the underside of the valve body 10 and has a concave cross section that opens downward, and has substantially the same shape as the communication groove 17. The communication grooves 17 and 17' are arranged to overlap in the circumferential direction and the up-down direction when viewed from above.

[0051] Similarly, the cylindrical portion 18' has substantially the same shape as the cylindrical portion 18, and extends downward from the bottom surface of the communicating groove 17'.

[0052] Next, examples of each flow path pattern of the switching valve V and the rotational positions of the valve element 10 that constitute each flow path pattern will be described using Figures 6 to 10. For ease of explanation, each of Figures 6 to 10 (b) shows the valve element 10 as seen from above, and the first port P1 to the eighth port P8 are indicated by two-dot chain lines. Furthermore, each of the formed flow paths is indicated by a different dot.

[0053] [First Flow Path Pattern] Figure 6(a) shows the first flow path pattern of the switching valve V. Figure 6(b) shows the rotational positions of the valve element 10 that constitutes the first flow path pattern.

[0054] In the first flow path pattern of the switching valve V, the second port P2 communicates with the sixth port P6 through the through hole 16 of the valve body 10. The fourth port P4 communicates with the eighth port P8 through the through hole 13 of the valve body 10. The fifth port P5 communicates with the first port P1 through the through hole 15 of the valve body 10. The seventh port P7 communicates with the third port P3 through the through hole 11 of the valve body 10.

[0055] The rotational position of the valve element 10 in the first flow path pattern of the switching valve V is the initial position of the valve element 10.

[0056] [Second Flow Path Pattern] Figure 7(a) shows a second flow path pattern of the switching valve V. Figure 7(b) shows the rotational position of the valve element 10 that constitutes the second flow path pattern.

[0057] In the second flow path pattern of the switching valve V, the valve element 10 is rotated 45 degrees counterclockwise from the rotation position in the first flow path pattern.

[0058] In the second flow path pattern of the switching valve V, the second port P2 communicates with the first port P1 through the communication groove 17. The fourth port P4 communicates with the eighth port P8 through the through hole 14 of the valve body 10. The fifth port P5 communicates with the sixth port P6 through the communication groove 17' of the valve body 10. The seventh port P7 communicates with the third port P3 through the through hole 12 of the valve body 10.

[0059] [Third Flow Path Pattern] Figure 8(a) shows a third flow path pattern of the switching valve V. Figure 8(b) shows the rotational positions of the valve element 10 that constitutes the third flow path pattern.

[0060] In the third flow path pattern of the switching valve V, the valve element 10 is rotated 90 degrees counterclockwise from the rotation position in the second flow path pattern.

[0061] In the third flow path pattern of the switching valve V, the second port P2 communicates with the sixth port P6 through the through hole 12 of the valve element 10. The fourth port P4 communicates with the first port P1 through the communication groove 17 of the valve element 10. The fifth port P5 communicates with the eighth port P8 through the communication groove 17' of the valve element 10. The seventh port P7 communicates with the third port P3 through the through hole 14 of the valve element 10.

[0062] [Fourth Flow Path Pattern] Figure 9(a) shows a fourth flow path pattern of the switching valve V. Figure 9(b) shows the rotational positions of the valve element 10 that constitutes the fourth flow path pattern.

[0063] In the fourth flow path pattern of the switching valve V, the valve element 10 is rotated 90 degrees counterclockwise from the rotation position in the third flow path pattern.

[0064] In the fourth flow path pattern of the switching valve V, the second port P2 communicates with the sixth port P6 through the through hole 14 of the valve element 10. The fourth port P4 communicates with the third port P3 through the communication groove 17 of the valve element 10. The fifth port P5 communicates with the first port P1 through the through hole 12 of the valve element 10. The seventh port P7 communicates with the eighth port P8 through the communication groove 17' of the valve element 10.

[0065] [Fifth Flow Path Pattern] Figure 10(a) shows a fifth flow path pattern of the switching valve V. Figure 10(b) shows the rotational positions of the valve element 10 that constitutes the fifth flow path pattern.

[0066] In the fifth flow path pattern of the switching valve V, the valve element 10 is rotated 90 degrees counterclockwise from the rotation position in the fourth flow path pattern.

[0067] In the fifth flow path pattern of the switching valve V, the second port P2 communicates with the third port P3 through the communication groove 17 of the valve element 10. The fourth port P4 communicates with the eighth port P8 through the through hole 12 of the valve element 10. The fifth port P5 communicates with the first port P1 through the through hole 14 of the valve element 10. The seventh port P7 communicates with the sixth port P6 through the communication groove 17' of the valve element 10.

[0068] Next, the state of fluid flowing through the communication groove 17 will be described with reference to Figure 11. Note that the description here will be given taking as an example the flow of fluid through the communication groove 17 in the second flow path pattern of the switching valve V.

[0069] 11 , in the second flow path pattern of the switching valve V, the second port P2 is connected to the first port P1 through the communication groove 17. The fluid supplied from the second port P2 is introduced from the peripheral portion 17B of the communication groove 17. The fluid branches off into a first passage R1, which is a short distance from the peripheral portion 17B to the peripheral portion 17C, and a second passage R2, which is a long way from the peripheral portion 17B to the peripheral portion 17C. The fluid flowing through the first passage R1 and the fluid flowing through the second passage R2 then join together, flow into the peripheral portion 17C, and are discharged to the first port P1.

[0070] In this way, the fluid flowing in the communicating groove 17 flows around the cylindrical portion 18 provided at the center of the valve element 10, so the influence of the fluid flowing in the communicating groove 17 is dispersed to both sides of the cylindrical portion 18, preventing tilt of the valve element 10 and stabilizing the posture of the valve element 10. Furthermore, the posture of the valve element 10 can be stabilized regardless of the shape of the communicating groove 17.

[0071] Furthermore, the volume VL1 of the central portion 17A around the cylindrical portion 18 of the communicating groove 17 is larger than the combined volume VL2 of the peripheral portions 17B and 17C. Therefore, the fluid pressure acts mainly on the central portion 17A of the communicating groove 17, which is in the vicinity of the rotation axis 61 of the valve body 10, and the influence of the fluid pressure acting on the peripheral portion 17B, which is the outer periphery of the valve body 10, is suppressed, making it easier to stabilize the posture of the valve body 10.

[0072] Furthermore, since the outer peripheral surface of the cylindrical portion 18 is a curved surface, vortexes and the like are unlikely to occur around the cylindrical portion 18, and the fluid flows smoothly around the cylindrical portion 18.

[0073] In addition, the inner surface of the communicating groove 17 is composed of a curved surface, and the fluid flows smoothly along the inner surface 17b of the boundary between the peripheral portion 17B and the central portion 17A, the inner surface 17a of the central portion 17A, the inner surface 17c of the boundary between the central portion 17A and the peripheral portion 17C, and the inner surface 17d of the boundary between the peripheral portions 17B and 17C.

[0074] Furthermore, the side walls 17Ba and 17Bb of the peripheral portion 17B extend so as to widen toward the center portion 17A. In other words, the side walls 17Ba and 17Bb of the peripheral portion 17B extend so as to widen toward the center of the valve body 10, i.e., the center of the cylindrical portion 18. More specifically, the peripheral portion 17B has an axisymmetric shape with respect to an imaginary line β extending in the radial direction. Therefore, fluid easily flows from the peripheral portion 17B to branch into a first passage R1 and a second passage R2 on either side of the cylindrical portion 18 in the center portion 17A.

[0075] Similarly, the side walls 17Ca and 17Cb of the peripheral portion 17C extend so as to widen toward the central portion 17A, making it easier for fluid to flow from the first passage R1 and the second passage R2 on both sides of the cylindrical portion 18 in the central portion 17A to the peripheral portion 17C.

[0076] Furthermore, the flow path cross-sectional area A1 of the first passage R1 and the flow path cross-sectional area A2 of the second passage R2 on either side of the cylindrical portion 18 are approximately the same size, so that the difference in fluid flow between the first passage R1 and the second passage R2 can be reduced.

[0077] Furthermore, since the communication groove 17 has the first passage R1, which has a shorter flow path length than the second passage R2, the fluid can flow efficiently. Furthermore, the shape of the communication groove 17 in this embodiment is such that the peripheral portions 17B, 17C are arranged at 90 degrees offset in the circumferential direction, so that at least four flow path patterns can be configured using the communication groove 17, thereby increasing the number of flow path patterns.

[0078] Furthermore, the communication groove 17 has an axisymmetric shape with respect to an imaginary line α that extends radially through the cylindrical portion 18 to separate the peripheral portions 17B and 17C. This allows the fluid flow to be distributed in a balanced manner between the peripheral portion 17B side and the peripheral portion 17C side of the communication groove 17, stabilizing the posture of the valve body 10.

[0079] Furthermore, the valve element 10 of the first embodiment has communicating grooves 17, 17' on its upper and lower surfaces, and these communicating grooves 17, 17' are arranged at the same position in the circumferential direction and the up-down direction when viewed from above, so that the fluid acts in a balanced manner on both surfaces of the valve element 10, stabilizing the position of the valve element 10. Furthermore, assembly is easy because the valve element 10 can be assembled regardless of its up-down orientation.

[0080] Furthermore, through holes 11 to 16 are formed on both sides of the communicating groove 17, sandwiching the cylindrical portion 18. Specifically, the through holes 11 and 15, and the through holes 13 and 16 are arranged symmetrically on either side of the communicating groove 17, on the outside of the communicating groove 17, with the cylindrical portion 18 in between. For example, if the pressure inside the communicating groove 17 becomes excessively high when starting the fluid circuit or switching the rotational position of the valve element 10, the communicating groove 17 may separate from the upper stator 54. In this case, the fluid inside the communicating groove 17 can be released approximately evenly to the through holes 11 and 15, and the through holes 13 and 16 on both sides, thereby stabilizing the posture of the valve element 10.

[0081] Furthermore, the valve element 10 is sandwiched from above and below by the upper stator 54 and the lower stator 55, and the upper stator 54 is biased toward the valve element 10 by the coiled wave spring 56. This allows the valve element 10 to maintain contact with the upper stator 54 and the lower stator 55, and also allows the biasing force of the coiled wave spring 56 to absorb any tilt of the valve element 10.

[0082] Next, a switching valve according to a second embodiment will be described with reference to Fig. 12. Note that the same configuration as in the first embodiment will be omitted.

[0083] As shown in FIG. 12, a valve body 210 of the second embodiment is provided with through holes 211, 212, 213, 214, 215, and 216, a communication groove 217, and a cylindrical portion 218 serving as a core.

[0084] Through hole 211 is provided at a position between 1 o'clock and 2 o'clock on valve body 210 when viewed from above. Through hole 212 is provided at a position between 3 o'clock on valve body 210. Through hole 213 is provided at a position between 4 o'clock and 5 o'clock on valve body 210. Through hole 214 is provided at a position between 7 o'clock and 8 o'clock on valve body 210. Through hole 215 is provided at a position between 9 o'clock on valve body 210. Through hole 216 is provided at a position between 10 o'clock and 11 o'clock on valve body 210.

[0085] The communication groove 217 is a groove with a concave cross section that opens upward. The communication groove 217 has a portion (i.e., a central portion 217A) that is provided on the inner diameter side of the through holes 211 to 216 in the valve body 210, and portions (i.e., peripheral portions 217B, 217C) that bulge out at the 12 o'clock and 6 o'clock positions of the valve body 210.

[0086] A cylindrical portion 218 is provided on the bottom surface of this communication groove 217, i.e., at the center of the valve body 210. A hole 217a is provided on the bottom surface of a peripheral portion 217B that bulges out at the 12 o'clock position of the communication groove 217. In other words, the hole 217a constitutes a part of the communication groove 217.

[0087] When fluid is introduced from the upper inlet port through the peripheral portion 217C of this communicating groove 217, it branches into the first passage R10 and the second passage R20 on either side of the cylindrical portion 218, then merges and flows into the peripheral portion 217B, and is then discharged to the lower outlet port through the hole portion 217a.

[0088] In addition, fluid may be introduced from the inlet port through the hole 217a from the peripheral portion 217B of the communication groove 217, and may be led out to the outlet port through the peripheral portion 217C.

[0089] In this way, the fluid flowing in the communication groove 217 flows in a balanced manner around the cylindrical portion 218 provided at the center of the valve element 210, so the attitude of the valve element 210 is stable.

[0090] Furthermore, the side walls 217Ba and 217Bb of the peripheral portion 217B extend so as to widen toward the central portion 217A. Specifically, the peripheral portion 217B has an axisymmetric shape with respect to an imaginary line α' extending in the radial direction. This allows fluid to easily flow from the first passage R10 and the second passage R20 on both sides of the cylindrical portion 218 in the central portion 217A to the peripheral portion 217B.

[0091] Similarly, the peripheral portion 217C has side walls 217Ca and 217Cb that extend so as to widen toward the central portion 217A, and the peripheral portion 217C branches into a first passage R10 and a second passage R20 on either side of the cylindrical portion 218 in the central portion 217A, making it easier for the fluid to flow.

[0092] Furthermore, since the communication groove 217 has a shape that is symmetrical with respect to the imaginary line γ that is perpendicular to the imaginary line α′, the position of the valve body 210 can be further stabilized.

[0093] Next, modified examples of the valve body of the present invention will be described with reference to Figures 13 to 15. Note that the same configuration as in the first embodiment will be omitted.

[0094] As shown in FIG. 13, a valve body 310 of the first modification is provided with through holes 311 and 312, a communication groove 317, and a cylindrical portion 318 serving as a core.

[0095] The through-hole 311 is provided at the 3 o'clock position of the valve body 310 when viewed from above. The through-hole 312 is provided at the 9 o'clock position of the valve body 310 when viewed from above.

[0096] The communication groove 317 has a portion provided in the center of the valve body 310 (i.e., a central portion 317A) and portions that bulge out at the 12 o'clock and 6 o'clock positions of the valve body 310 (i.e., peripheral portions 317B, 317C).

[0097] As shown in FIG. 14, a valve body 410 of the second modification is provided with through holes 411 and 412, a communication groove 417, and a cylindrical portion 418 serving as a core.

[0098] The through-hole 411 is provided at a position between 10 o'clock and 11 o'clock on the valve body 410 when viewed from above. The through-hole 412 is provided at a position between 4 o'clock and 5 o'clock on the valve body 410 when viewed from above.

[0099] The communicating groove 417 has a portion provided in the center of the valve body 410 (i.e., the central portion 417A) and portions that bulge out at the 12 o'clock position and at a position between 7 o'clock and 8 o'clock on the valve body 410 (i.e., peripheral portions 417B, 417C).

[0100] As such, as in variant 1 of Figure 13 and variant 2 of Figure 14, the number of through holes may be freely changed, and preferably, through holes should be provided on both sides of the communicating groove that sandwich the core.

[0101] As shown in FIG. 15, a valve body 510 of the third modification is provided with through holes 511, 512, 513, 514, 515, and 516, a communication groove 517, and a cylindrical portion 518 serving as a core.

[0102] The communicating groove 517 has a portion provided in the center of the valve body 510 (i.e., the central portion 517A) and portions that bulge out at the 12 o'clock, 4 o'clock, and 8 o'clock positions of the valve body 510 (i.e., peripheral portions 517B, 517C, and 517D).

[0103] The through holes 511 and 512 are equally spaced in the circumferential direction between the peripheral portions 517B and 517C. The through holes 513 and 514 are equally spaced in the circumferential direction between the peripheral portions 517C and 517D. The through holes 515 and 516 are equally spaced in the circumferential direction between the peripheral portions 517B and 517D.

[0104] As in the third modification of FIG. 15, the shape of the communication groove may be freely changed, and it is preferable that the through holes are arranged in a balanced manner around the communication groove.

[0105] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0106] For example, in the first and second embodiments, four inlet ports and four outlet ports are illustrated, but the number of inlet ports and outlet ports can be freely changed as long as there are two or more of each. Furthermore, the number of inlet ports and outlet ports does not have to be the same, and different numbers may be provided.

[0107] In addition, in the first and second embodiments, the inlet port and the outlet port are provided on one side and the other side of the housing, respectively, but they may be provided on only one side or the other side of the housing.

[0108] In addition, in the first and second embodiments, the communicating passage extends from one through hole, inlet port, or outlet port so as to straddle one or more through holes, in other words, so as to skip one or more circumferentially adjacent through holes, but the communicating passage may extend so as to connect adjacent through holes in the valve body as long as it can communicate one through hole, inlet port, or outlet port with another through hole, inlet port, or outlet port. Note that the communicating passage spanning one or more through holes described in the embodiments is preferable because it makes it easy to form various flow path patterns and because the fluid pressure acting in the vertical direction from the fluid introduced into the communicating passage is easily averaged across the surface of the valve body.

[0109] In addition, although the first and second embodiments illustrate a configuration in which a plurality of through holes are provided in the valve body, the number of through holes may be one. Furthermore, for example, when the valve is applied to a switching valve in which a communication groove branches from one inlet port to multiple outlet ports, a through hole may not be provided.

[0110] In addition, in the first and second embodiments, the communicating grooves are provided on both the upper and lower surfaces of the valve body, but they may be provided on at least one surface. Also, multiple communicating grooves may be provided on either the upper or lower surface of the valve body.

[0111] In addition, although the core is cylindrical in the first and second embodiments, it may be a columnar core. The rotation axis may also serve as the core. The core may also be a cylinder or a column with a polygonal or elliptical cross section.

[0112] In addition, in the first and second embodiments, the upper stator is biased against the valve body by a coiled wave spring. However, the lower stator may be biased against the valve body by a coiled wave spring, or both the upper stator and the lower stator may be biased against the valve body.

[0113] The biasing means is not limited to a coiled wave spring. If the biasing means can be in sealed contact with the stator, the biasing means may be omitted.

[0114] Furthermore, the stator does not necessarily have to be disposed above or below the valve body, but may be disposed either above or below the valve body.Furthermore, the stator may be omitted, and the valve body may directly contact the upper and lower covers of the housing.

[0115] In addition, in the first and second embodiments, the valve element is rotatably driven by a rotary shaft, but the valve element may be rotatably supported on a fixed shaft and may be rotated by a drive means including, for example, a motor, a gearbox, and a rotary encoder. In other words, the configuration of the drive device can be freely changed as long as the valve element is rotatable.

[0116] 10 Valve body 11 to 16 Through hole 17, 17' Communication groove 17A Central portion 17B, 17C Peripheral portion 17a Inner surface 18, 18' Cylindrical portion (core) 50 Housing 54 Upper stator 55 Lower stator 56 Coiled wave spring (biasing means) 61 Rotating shaft A1, A2 Flow path cross-sectional area P1 First port (outlet port) P2 Second port (inlet port) P3 Third port (outlet port) P4 Fourth port (inlet port) P5 Fifth port (inlet port) P6 Sixth port (outlet port) P7 Seventh port (inlet port) P8 Eighth port (outlet port) R1 First passage R2 Second passage V Switching valve

Claims

1. A switching valve comprising: a housing; a plurality of ports provided in the housing; a valve element having communication grooves connecting the plurality of ports and rotatably arranged within the housing; and a rotary shaft connected to the valve element and rotating the valve element, wherein the valve element has a core formed within the communication groove coaxially with the rotary shaft, and the communication groove has a central portion surrounding the core and a peripheral portion extending radially outward from the central portion.

2. A switching valve according to claim 1, wherein the core is cylindrical or columnar.

3. A switching valve according to claim 1, wherein the inner surface of said communication groove is formed as a curved surface.

4. A switching valve according to claim 1, wherein the ratio of the cross-sectional areas of the flow passages on both sides of the core in the communicating groove is less than two.

5. A switching valve according to claim 1, wherein the valve body has through holes formed on both sides of the communicating groove, sandwiching the core.

6. A switching valve according to claim 1, wherein said communication groove is shaped symmetrically with respect to a line extending in the radial direction and passing through said core.

7. A switching valve according to claim 1, wherein the communication grooves are provided at overlapping positions on both sides of the valve body.

8. A switching valve according to claim 1, wherein said peripheral portion extends so as to widen toward said central portion.

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