JP7023525B2 - Flow switching valve - Google Patents

Description

The present invention relates to a flow path switching valve in which a valve body having a U-turn communication path formed of a U-turn-shaped communication space is arranged in a housing, and particularly performs flow path switching in a heat pump type heating / cooling system or the like. The present invention relates to a flow switching valve suitable for the above.

Conventionally, a flow path switching valve such as a four-way switching valve or a six-way switching valve has been well known as a flow path (flow direction) switching means of a heat pump type heating / cooling system. As this type of flow path switching valve, a slide type valve body in which a slide valve body is slidably arranged in a cylinder type housing and a rotary valve body in which a rotary valve body is rotatably arranged in a cylindrical housing are arranged. There is a rotary type. Further, a valve in which a U-turn-shaped communication space (hereinafter referred to as a U-turn communication passage) for communicating adjacent ports is formed in this flow path switching valve so as to selectively communicate between ports provided in the housing. It is also known to use a body (see, for example, Patent Document 1 below).

FIG. 4 shows a conventional flow path switching valve. The flow path switching valve of the conventional example shown is, for example, a slide type four-way switching valve 1'used for flow path switching in a heat pump type heating / cooling system, and is a cylinder type housing 80 and a valve provided in the housing 80. Port pC, port pS (low pressure port), port pE, and valve seat surface provided laterally in the left-right direction, which are opened in the seat member 81 and the valve seat surface 82 formed on the upper surface of the valve seat member 81. It has a valve body (slide valve body) 10 having an inverted bowl-shaped cross section and is slidably arranged on the 82 in the left-right direction.

The valve body 10 has a sealing surface 12 facing the valve seat surface 82, and in the valve body 10, the three ports pC, pS, and pE are selectively communicated with each other, in other words, with the port pS. A U-turn communication passage 15 is provided in order to create a first communication state in which the port pE is communicated and a second communication state in which the port pS and the port pC are communicated with each other.

The lid members 87A and 87B are airtightly fixed to both ends of the housing 80, and the inside of the housing 80 is airtightly partitioned by two pistons 84A and 84B with packings on the left and right, and the valve chamber 83 and the two operating chambers. 86A and 86B are defined. A port pD (high pressure port) connected to the discharge side of the compressor is opened in the valve chamber 83.

The two pistons 84A and 84B are integrally movably connected by a horizontally long rectangular plate-shaped connecting body 70. The connecting body 70 is formed with an opening 72 into which the valve body 10 is slidably fitted from below, and the valve body 10 is formed by the reciprocating movement of the two pistons 84A and 84B. The right end position (first communication state) in which the port pE and the port pS are communicated via the U-turn communication passage 15 pushed by the opening 72 portion and formed inside the opening, and the port pC and the port pS are communicated with each other. It is designed to slide between the left end position (second communication state) and the left end position. Note that FIG. 4 shows the second communication state.

Further, the connecting body 70 is formed with circular openings 75 on the left and right sides of the opening 72.

The two operating chambers 86A and 86B are selectively connected to the compressor discharge side and the compressor suction side via a four-way pilot valve (not shown in FIG. 4 and shown in FIG. 1), and the two operating chambers 86A are connected. , 86B is used to move the pistons 84A and 84B, and the valve body 10 is slid on the valve seat surface 82 to switch the flow path.

Further, the valve body 10 (seal surface 12) on which the U-turn continuous passage 15 is formed as described above is a high-pressure fluid circulating on the outside (inside the valve chamber 83) and inside (inside the U-turn continuous passage 15). It is strongly pressed against the valve seat surface 82 by the pressure difference with the low-pressure fluid flowing through the U-turn, whereby the U-turn continuous passage 15 is sealed (sealing property is ensured).

Japanese Unexamined Patent Publication No. 2013-227989

By the way, in recent years, the balance between high-pressure flow rate and low-pressure flow rate has been adjusted by improving the performance efficiency of the heating / cooling system. For example, in the case of a valve body of a slide type flow path switching valve, the Cv value (corresponding to the flow rate) is greatly affected by the longitudinal direction (axis direction) dimension of the U-turn communication passage provided inside. For example, when lowering the Cv value (that is, when reducing the low pressure flow rate with respect to the high pressure flow rate), it is necessary to reduce the above-mentioned dimensions, and as shown in FIG. 4, the U-turn continuous passage as the inner diameter portion of the valve body. The opening edge of the valve seat member is arranged inside the peripheral edge (inner peripheral edge) of the port as the inner diameter portion of the valve seat member.

However, if the opening edge of the U-turn passage is too inward of the peripheral edge (inner peripheral edge) of the port, for example, a valve body made of synthetic resin is slightly deformed by a pressing force due to a long-term differential pressure. A deformed protrusion is formed below the sliding surface (a seal surface that is in sliding contact with the valve seat surface) (see the deformed protrusion 10A in FIG. 4). If the valve body moves in this state, the above-mentioned deformed protrusion may be caught on the peripheral edge of the port, ride on the valve seat surface, or the like, resulting in valve leakage or malfunction. In addition, when the valve body moves, the above-mentioned deformed protrusions may be scraped to deform the sliding surface, or the scraped foreign matter may be caught in the sliding surface, causing valve leakage or malfunction.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the influence of deformation due to the differential pressure inside and outside the valve body as much as possible, resulting in valve leakage and malfunction. The purpose is to provide a flow path switching valve that can be made difficult.

In order to achieve the above object, the flow path switching valve according to the present invention basically includes a cylinder type housing, a valve body movably arranged in the housing in the axial direction, and the valve body. A valve seat surface that is opposed to each other and has a plurality of ports opened side by side in the axial direction is provided, and the valve body is provided on the inside of a sealing surface that is in sliding contact with the valve seat surface, among the plurality of ports. It has a U-turn communication passage having a size for communicating adjacent ports, and can take a plurality of communication states for selectively communicating between the ports via the U-turn communication passage, and the valve body is predetermined. The axial end of the opening edge of the U-turn communication passage is arranged inside the peripheral edge of the port, and the valve is located at the axial end of the inner edge of the sealing surface. A flank recessed on the side opposite to the seat surface side is continuously provided, and the flank is formed of a tapered surface inclined with respect to the seal surface, and the valve body takes a predetermined communication state. The inner edge of the sealing surface is characterized in that it is positioned at a position that coincides with the peripheral edge of the port and at least on both sides of the valve body in the moving direction.

In another preferred embodiment, when the valve body is in a predetermined communication state, both axial ends of the opening edge of the U-turn communication passage are located inside the perimeter of the port.

In another preferred embodiment, the opening edge of the U-turn passage is located at a pair of semicircular portions located at the axial end and at the end perpendicular to the axial direction and extends along the axial direction. It is composed of a pair of straight sections.

In another preferred embodiment, the axial end of the opening edge of the U-turn passage is configured with a surface perpendicular to the sealing surface.

Further , the flow path switching valve according to the present invention basically has a tubular housing, a valve body movably arranged in the housing, and a plurality of ports in which the valve body is brought into contact with each other. The valve body is provided with a valve seat surface that is opened side by side, and the valve body is a U-turn having a size that allows adjacent ports among the plurality of ports to communicate with each other inside a sealing surface that is in sliding contact with the valve seat surface. When a plurality of communication states having a communication path and selectively communicating between the ports via the U-turn communication path are obtained and the valve body takes a predetermined communication state, the U-turn communication is performed. The side-by-side end of the adjacent port of the opening edge of the passage is arranged inside the peripheral edge of the port, and the side-by-side end of the adjacent port on the inner edge of the sealing surface is the same. A flank recessed on the side opposite to the valve seat surface side is continuously provided, and the flank is formed of a tapered surface inclined with respect to the seal surface, and the valve body is in a predetermined communication state. When taken, the inner edge of the sealing surface is characterized in that it is positioned at a position that coincides with the peripheral edge of the port and at least on both sides of the valve body in the moving direction.

In a preferred embodiment, the valve body is a slide valve body movably arranged in the axial direction of the housing, or a rotary valve body rotatably arranged around a rotation axis parallel to the axis of the housing. To prepare for.

In the flow path switching valve of the present invention, when the valve body takes a predetermined communication state, the axial end portion (parallel arrangement direction end portion of adjacent ports) of the opening edge portion of the U-turn communication passage is closer than the peripheral edge of the port. A stepped surface that is placed inside and is recessed on the side opposite to the valve seat surface side at the axial end (the side-by-side end of adjacent ports) of the inner edge of the seal surface that slides into contact with the valve seat surface. Since a relief surface made of a tapered surface or the like is provided, the deformed protrusion is not formed below the sealing surface of the valve body even if a pressing force due to the differential pressure is generated. Therefore, for example, as compared with the conventional one having no flank, it is less susceptible to the deformation due to the differential pressure inside and outside the valve body, and as a result, the influence of the deformation due to the differential pressure inside and outside the valve body is possible. It can be reduced in number, and valve leakage and malfunction can be less likely to occur.

The whole vertical sectional view which shows one Embodiment of the flow path switching valve which concerns on this invention. The bottom view of the valve body shown in FIG. (A) and (B) are enlarged vertical sectional views of a main part showing another embodiment of the flow path switching valve according to the present invention, respectively. A vertical sectional view showing a conventional flow path switching valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an overall vertical sectional view showing an embodiment of a flow path switching valve according to the present invention. FIG. 2 is a bottom view of the valve body shown in FIG. In FIG. 2, the positions of the ports pC, pS, and pE provided on the seat member are illustrated by virtual lines.

In addition, in this specification, the description indicating the position and direction such as up / down, left / right, front / back, etc. is added for convenience according to the drawing in order to avoid complicated explanation, and is actually incorporated in the air conditioning system or the like. It does not always point to the position or direction in the state.

Further, in each drawing, the gap formed between the members, the separation distance between the members, etc. are larger than the dimensions of each constituent member in order to facilitate understanding of the invention and for convenience in drawing. Or it may be drawn small.

The flow path switching valve of the illustrated embodiment is, for example, a slide type four-way switching valve 1 used for flow path switching in a heat pump type heating / cooling system, and includes a main valve 9 having a valve body (slide valve body) 10 built therein. It is equipped with a four-way pilot valve 8.

The main valve 9 opens into a cylinder-shaped (cylindrical) housing 80, a valve seat member 81 provided in the housing 80, and a flat and smooth valve seat surface 82 formed on the upper surface of the valve seat member 81. , Port pC, port pS (low pressure port), and port pE provided side by side in the left-right direction (length of housing 80 or axis O direction), and slidably arranged on the valve seat surface 82 in the left-right direction. It has a valve body 10 having an inverted bowl-shaped cross section.

The valve body 10 is made of, for example, a synthetic resin, and has a sealing surface 12 that faces (faces) the valve seat surface 82, and the three ports are inside the valve body 10, that is, inside the sealing surface 12. To selectively communicate pC, pS, and pE, in other words, to create a first communication state in which port pS and port pE communicate with each other, and a second communication state in which port pS and port pC communicate with each other. , U-turn communication passage 15 is provided.

The lid members 87A and 87B are airtightly fixed to both ends of the housing 80, and the inside of the housing 80 is airtightly partitioned by two (pair) packing pistons 84A and 84B on the left and right, and the valve chamber 83 and the valve chamber 83. Two working chambers 86A and 86B are defined. A port pD (high pressure port) connected to the discharge side of the compressor is opened in the valve chamber 83 (in the illustrated example, a position facing the central port pS).

The two pistons 84A and 84B are integrally movably connected by a horizontally long rectangular plate-shaped connecting body 70. The connecting body 70 is formed with a rectangular opening 72 into which the valve body 10 is slidably fitted from below, and the valve body 10 is connected as the two pistons 84A and 84B reciprocate. The right end position (first communication state) that is pushed by the opening 72 portion of the body 70 and communicates the port pE and the port pS (low pressure port) via the U-turn communication passage 15 formed inside the body 70, and the port. It is made to slide between the left end position (second communication state) in which the pC and the port pS (low pressure port) are communicated with each other. Note that FIG. 1 shows the second communication state.

Further, in the connecting body 70, a circular opening 75 is formed on the left and right sides of the opening 72, that is, at a portion located substantially directly above the port pC on the left side when the valve body 10 takes the right end position (first communication state). At the same time, when the valve body 10 takes the left end position (second communication state), a circular opening 75 is formed at a portion located substantially directly above the port pE on the right side.

In the main valve 9, the two operating chambers 86A and 86B are selectively connected to the compressor discharge side and the compressor suction side via the four-way pilot valve 8 and the thin tubes # 1 to # 4, and the two actuation chambers 86A and 86B are operated. The pistons 84A and 84B are moved by utilizing the pressure difference between the chambers 86A and 86B, and the valve body 10 is slid on the valve seat surface 82 accordingly to switch the flow path.

Further, the valve body 10 (seal surface 12) on which the U-turn continuous passage 15 is formed as described above is a high-pressure fluid circulating on the outside (inside the valve chamber 83) and inside (inside the U-turn continuous passage 15). It is strongly pressed against the valve seat surface 82 by the pressure difference with the low-pressure fluid flowing through the U-turn, whereby the U-turn continuous passage 15 is sealed (sealing property is ensured).

Next, the circumference of the valve body 10, which is the main part of the four-way switching valve (flow path switching valve) 1 of the above embodiment, will be described in detail.

In the present embodiment, as can be clearly seen with reference to FIG. 2, the inner edge portions 12C of the annular sealing surface 12 of the valve body 10 are a pair of left and right semicircular portions 13A located at both ends in the left-right direction (longitudinal direction). , 13B and a pair of front and rear straight lines 14A that are located at both ends in the front-rear direction (short direction) and extend along the longitudinal direction and connect the pair of left and right semicircle portions 13A and 13B (ends). , 14B and has a schematic race track shape in plan view.

The diameters of the pair of left and right semicircular portions 13A and 13B and the distance between the pair of front and rear straight portions 14A and 14B are slightly larger than the diameters (inner diameters) of the ports pC, pS and pE opened in the valve seat surface 82. It has been made larger.

When the valve body 10 takes the right end position, the left semicircular portion 13A is located on the left side (outside) of the peripheral edge of the port pS on the exit side, and the right semicircular portion 13B is located on the peripheral edge of the port pE on the inlet side. When the valve body 10 is located on the right side (outside) and the valve body 10 takes the left end position, the left semicircle portion 13A is located on the left side (outside) of the peripheral edge of the port pC which is the inlet side, and the right semicircle portion 13B is the exit. It is located on the right side (outside) of the peripheral edge of the side port pS. Further, the front and rear straight portions 14A and 14B are located on the front side and the rear side of the three ports pC, pS and pE, respectively.

Further, the U-turn communication passage 15 provided inside the sealing surface 12 of the valve body 10 is an adjacent port (that is, the valve seat surface 82 side in which the ports pC, pS, and pE are opened) is opened. It has a substantially inverted U-shape or a concave shape in a side view having a size that allows pC-pS or pS-pE) to communicate with each other.

The opening edge portion 15C of the U-turn continuous passage 15 has a pair of left and right semicircular portions 16A and 16B located at both ends in the left-right direction (longitudinal direction) in the front-rear direction, similarly to the inner edge portion 12C of the sealing surface 12 described above. (Short side direction) It is located at both ends and extends along the longitudinal direction, and includes a pair of front and rear straight portions 17A and 17B connecting the pair of left and right semicircular portions 16A and 16B (ends). It has a rough race track shape in plan view.

The diameters of the pair of left and right semicircular portions 16A and 16B and the distance between the pair of front and rear straight portions 17A and 17B are slightly larger than the diameters (inner diameters) of the ports pC, pS and pE opened in the valve seat surface 82. Although it is made larger, the distance between the pair of left and right semicircle portions 16A and 16B (in the left-right direction) is slightly shorter than the distance between the pair of left and right semicircle portions 13A and 13B (in the left-right direction). The opening edge portion 15C of the turn passage 15 is slightly shorter in the left-right direction (longitudinal direction) than the inner edge portion 12C of the sealing surface 12 (that is, the semicircular portions 16A and 16B are the semicircular portions 13A and 13B. Is located inside).

Further, in this example, the pair of left and right semicircular portions 16A and 16B located at both ends of the opening edge portion 15C of the U-turn continuous passage 15 are configured with a surface substantially perpendicular to the sealing surface 12.

When the valve body 10 takes the right end position, the left semicircular portion 16A is located on the right side (inside) of the peripheral edge of the port pS on the exit side, and the right semicircular portion 16B is located on the peripheral edge of the port pE on the inlet side. When the valve body 10 is located on the left side (inside) and the valve body 10 is in the left end position, the left semicircle portion 16A is located on the right side (inside) of the peripheral edge of the port pC which is the inlet side, and the right semicircle portion 16B is the exit. It is located on the left side (inside) of the peripheral edge of the side port pS. Further, the front and rear straight portions 17A and 17B are located on the front side and the rear side of the three ports pC, pS and pE, respectively.

In this example, the U-turn continuous passage 15 (internal space) has a substantially equal cross-sectional area (passage cross-sectional area) from one end to the other end (except for both ends provided with the escape surface 19 described later). Is formed to have.

Then, in the present embodiment, in order to avoid the influence of deformation due to the differential pressure inside and outside the valve body 10, the semicircular portions 13A and 13B of the inner edge portion 12C of the sealing surface 12 on the valve body 10 are on the valve seat surface 82 side. Is connected with a recessed flank 19 on the opposite side.

In the present embodiment, the flank 19 is composed of a stepped surface extending stepwise to the semicircular portions 16A and 16B of the opening edge portion 15C of the U-turn continuous passage 15. Specifically, the flank surface 19 is a rising surface 19a that rises substantially vertically from the sealing surface 12 (semicircular portions 13A and 13B of the inner edge portion 12C) and substantially parallel to the sealing surface 12 from the rising surface 19a. It is configured to have a recessed surface 19b extending to the semicircular portions 16A and 16B of the opening edge portion 15C of the U-turn continuous passage 15. Further, the length of the recessed surface 19b in the left-right direction is made longer than the rising surface 19a on the center line (axis line O) and gradually shortened as it is separated from the center line (axis line O) (in the front-rear direction). There is.

In other words, in the present embodiment, it is composed of a stepped surface between the semicircular portions 13A and 13B of the inner edge portion 12C of the sealing surface 12 and the semicircular portions 16A and 16B of the opening edge portion 15C of the U-turn continuous passage 15. The flank 19 is interposed.

The depth (height) of the flank surface 19 (step surface), that is, the dimensions of the rising surface 19a and the recessed surface 19b are such that the valve body 10 is hardly deformed even when pressure is applied, and affects the Cv value. The dimensions are such that there is no such thing.

As described above, in the four-way switching valve (flow path switching valve) 1 of the present embodiment, the valve body 10 may be slightly deformed by the pressing force due to the differential pressure inside and outside the valve body 10, but the valve is a valve. When the body 10 takes the right end position (first communication state) or the left end position (second communication state), the semicircular portions 16A and 16B located at both ends in the left-right direction of the opening edge portion 15C of the U-turn communication passage 15. Are arranged inside the peripheral edge of the port, and the semicircular portions 13A and 13B located at both ends of the inner edge portion 12C of the seal surface 12 that is in sliding contact with the valve seat surface 82 in the left-right direction are on the valve seat surface 82 side. Since the escape surface 19 composed of the stepped surface recessed on the opposite side is provided, even if a pressing force due to the differential pressure is generated, the deformed protrusion portion is not formed below the seal surface 12 of the valve body 10. do not have. Therefore, for example, as compared with the conventional one having no flank, it is less likely to be affected by the deformation due to the differential pressure inside and outside the valve body 10, and as a result, the influence of the deformation due to the differential pressure inside and outside the valve body 10 is affected. It can be reduced as much as possible, and valve leakage and malfunction can be less likely to occur.

In the above-described embodiment, the stepped surface extending in a step shape is used as the flank surface 19, but the flank surface 19 formed on the inner edge portion 12C (semicircular portions 13A and 13B) of the seal surface 12 is used. As shown in FIGS. 3 (A) and 3 (B), the seal surface 12 is tilted at a predetermined angle (approximately 45 ° in FIG. 3 (A) and approximately 20 ° in FIG. 3 (B)). A tapered surface may be adopted. In the example shown in FIGS. 3A and 3B, the semicircular portions 13A and 13B of the inner edge portion 12C of the sealing surface 12 substantially coincide with the peripheral edge of the port (in other words, the same as the peripheral edge of the port). The dimensions and shape of each part are set so as to be (position). Further, in the examples shown in FIGS. 3A and 3B, a tapered surface made of a flat surface is adopted, but for example, a tapered surface made of a curved surface such that it is convex upward or convex downward may be adopted. That is natural.

As shown in FIGS. 3A and 3B, when a tapered surface is adopted as the escape surface 19, for example, as compared with the case where the stepped surface described above is used, the U-turn continuous passage 15 and each port are connected. Since the flow between them becomes smooth, the pressure loss can be reduced and the flow rate (Cv value) can be improved.

Further, in the above-described embodiment, when the valve body 10 takes the right end position or the left end position, both the semicircular portions 16A and 16B located at both ends in the left-right direction of the opening edge portion 15C of the U-turn continuous passage 15 are ports. Although it is arranged inside the peripheral edge of the port, it is needless to say that only one of the semicircle portions 16A and 16B may be arranged inside the peripheral edge of the port.

In the above embodiment, the four-way switching valve has been exemplified as the flow path switching valve, but the present invention has a two-way valve for switching the flow path by a valve body (slide valve body), a three-way switching valve, and the like. Of course, it can also be applied to a multi-way switching valve with five or more directions.

Further, in the above embodiment, a slide type valve is exemplified and described, but the present invention can rotate in a cylindrical housing (around a rotation axis parallel to the axis of the housing). Of course, it can also be applied to a rotary type that is arranged and switches the flow path by a valve body (rotary valve body) provided with (one or a plurality of) U-turn communication passages inside.

Further, it goes without saying that the four-way switching valve 1 of the present embodiment can be incorporated not only into a heat pump type heating / cooling system but also into other systems, devices, and devices.

1 Four-way switching valve (flow path switching valve)
8 Four-way pilot valve 9 Main valve 10 Valve body 12 Sealed surface 12C Sealed surface inner edge 13A, 13B Semicircular 14A, 14B Straight line 15 U-turn continuous passage 15C U-turn continuous passage opening edge 16A, 16B Semicircular 17A, 17B Straight part 19 Escape surface 70 Connecting body 72 Opening 75 Circular opening 80 Housing 81 Valve seat member 82 Valve seat surface 83 Valve chamber 84A, 84B Piston 86A, 86B Actuating chamber 87A, 87B Lid member

Claims (6)

A cylinder-type housing, a valve body movably arranged in the housing in the axial direction, and a valve seat surface in which the valve bodies are brought into contact with each other and a plurality of ports are opened side by side in the axial direction. , Equipped with
The valve body has a U-turn communication passage having a size that allows adjacent ports among the plurality of ports to communicate with each other inside the seal surface that is in sliding contact with the valve seat surface, and the valve body has the U-turn communication passage through the U-turn communication passage. It is a flow path switching valve that can take multiple communication states that selectively communicate between ports.
When the valve body takes a predetermined communication state, the axial end of the opening edge of the U-turn communication passage is arranged inside the peripheral edge of the port, and the valve body is arranged inside the peripheral edge of the port.
A flank recessed on the side opposite to the valve seat surface side is continuously provided at the axial end of the inner edge of the seal surface.
The flank surface is composed of a tapered surface inclined with respect to the sealing surface.
When the valve body takes a predetermined communication state, the inner edge portion of the sealing surface is positioned so as to coincide with the peripheral edge of the port and at least on both sides of the valve body in the moving direction. Flow switching valve. The first aspect of the present invention is characterized in that both of the axial end portions of the opening edge portion of the U-turn communication passage are arranged inside the peripheral edge of the port when the valve body takes a predetermined communication state. The flow path switching valve described. The opening edge of the U-turn passage is composed of a pair of semicircular portions located at the end in the axial direction and a pair of straight portions located at the end in the direction perpendicular to the axial direction and extending along the axial direction. The flow path switching valve according to claim 1 or 2 , wherein the flow path switching valve is configured. The flow path switching valve according to any one of claims 1 to 3 , wherein the axial end portion of the opening edge portion of the U-turn continuous passage is formed of a surface perpendicular to the sealing surface. .. It is provided with a cylindrical housing, a valve body movably arranged in the housing, and a valve seat surface to which the valve bodies are opposed to each other and a plurality of ports are opened side by side.
The valve body has a U-turn communication passage having a size that allows adjacent ports among the plurality of ports to communicate with each other inside the seal surface that is in sliding contact with the valve seat surface, and the valve body has the U-turn communication passage through the U-turn communication passage. It is a flow path switching valve that can take multiple communication states that selectively communicate between ports.
When the valve body takes a predetermined communication state, the end portion of the opening edge of the U-turn communication passage in the parallel direction of the adjacent ports is arranged inside the peripheral edge of the port, and the valve body is arranged inside the peripheral edge of the port.
At the end of the inner edge of the sealing surface in the parallel direction of the adjacent ports, a relief surface recessed on the side opposite to the valve seat surface side is continuously provided.
The flank surface is composed of a tapered surface inclined with respect to the seal surface.
When the valve body takes a predetermined communication state, the inner edge portion of the sealing surface is positioned so as to coincide with the peripheral edge of the port and at least on both sides of the valve body in the moving direction. Flow switching valve. The valve body includes a slide valve body movably arranged in the axial direction of the housing, or a rotary valve body rotatably arranged around a rotation axis parallel to the axis of the housing. The flow path switching valve according to claim 5 , which is characterized.

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