JP6999184B2 - Flow switching valve - Google Patents

Description

The present invention relates to a slide type flow path switching valve.

In a heat pump type air-conditioning system such as a room air conditioner or a car air conditioner, a flow path switching valve that switches the flow direction of the refrigerant according to the switching of the air-conditioning operation is used.

A conventional flow path switching valve is disclosed in Patent Document 1. As shown in FIG. 8, the flow path switching valve 901 is a six-way switching valve, which is slidably arranged in the cylindrical valve housing 910 and the valve housing 910 by being pushed by the bracket 953 in the L direction of the axis. It has a valve body 918 and. In the valve housing 910, a first valve seat 913 and a second valve seat 915 are provided so as to face each other in a direction orthogonal to the axis L. The first valve seat 913 is provided with three ports pB, pA, and pF arranged side by side in the L direction of the axis. The second valve seat 915 is provided with three other ports pC, pD, and pE arranged in order in the L direction of the axis so as to face the three ports pB, pA, and pF.

The valve body 918 has a first U-turn passage 928 that communicates two of the three ports (port pA and port pB, or port pA and port pF), and two of the other three ports. A second U-turn passage 929 for communicating ports (port pC and port pD, or port pE and port pD) is provided. Further, the valve body 918 is provided with a first straight passage 936 for communicating the port pC and the port pB, and a second straight passage 946 for communicating the port pE and the port pF.

Japanese Unexamined Patent Publication No. 2018-44666

In the flow path switching valve 901 described above, for example, the discharge portion of the compressor of the heat pump type heating / cooling system is connected to the port pA, and the high-pressure refrigerant flows through the port pA to the first U-turn passage 928. High-pressure refrigerant may cause pressure fluctuation (pulsation) due to the operation of the compressor. Therefore, a phenomenon (also referred to as “chattering”) in which the valve body 918 intermittently rises from the first valve seat 913 in accordance with the pulsation of the high-pressure refrigerant may occur, resulting in valve leakage. The same applies to the case where the high-pressure refrigerant flows through the second U-turn passage 929.

Therefore, an object of the present invention is to provide a flow path switching valve capable of effectively suppressing valve leakage caused by fluid pulsation.

In order to achieve the above object, the flow path switching valve of the present invention has a tubular valve housing provided with a valve chamber, a first valve seat arranged in the valve chamber, and the first valve chamber in the valve chamber. Flow path switching having a second valve seat arranged facing the valve seat and a U-turn valve body slidably arranged in the axial direction between the first valve seat and the second valve seat. A valve, the U-turn valve body has a first valve body portion arranged on the first valve seat side and a second valve body portion arranged on the second valve seat side. The first valve body portion is provided with a first U-turn passage for communicating two ports out of a plurality of ports provided in the first valve seat, and the second valve body portion is provided with the second valve seat. A second U-turn passage is provided to communicate two of the plurality of ports provided in the above, and a back communicating with the valve chamber is provided between the first valve body portion and the second valve body portion. A pressure space is provided, and the second valve body portion allows a pressure equalizing hole that communicates the second U-turn passage and the back pressure space, and allows fluid to move from the second U-turn passage to the back pressure space. It is characterized by having a pressure relief valve body that opens and closes the pressure equalizing hole so as to restrict the movement of the fluid from the back pressure space to the second U-turn passage.

According to the present invention, when the fluid pressure in the second U-turn passage rises due to the pulsation of the high-pressure fluid in a state where the high-pressure fluid flows in the second U-turn passage and the high-pressure fluid is introduced into the valve chamber, the pressure equalizing hole opens. The fluid moves from the second U-turn passage to the back pressure space. Therefore, the fluid pressure in the second U-turn passage can be released, and valve leakage due to the pulsation of the fluid can be effectively suppressed. Further, in a state where the low-pressure fluid or the medium-pressure fluid flows in the second U-turn passage and the high-pressure fluid flows in the valve chamber, the pressure equalizing hole is closed and the movement of the fluid from the back pressure space to the second U-turn passage is restricted. As a result, the second valve body portion is pressed against the second valve seat by the differential pressure between the pressure received from the low pressure fluid or the medium pressure fluid in the second U-turn passage and the pressure received from the high pressure fluid in the back pressure space. Therefore, it is possible to suppress the formation of a gap between the second valve body portion and the second valve seat, and effectively suppress valve leakage.

In the present invention, the first valve body portion is provided with a communication passage that communicates the valve chamber and the back pressure space, and the flow path area of the communication passage is smaller than the flow path area of the pressure equalizing hole. stomach. By doing so, the fluid pressure in the back pressure space changes more slowly. That is, when the fluid pressure in the second U-turn passage rises due to the pulsation of the high-pressure fluid, the pressure equalizing hole is opened and the fluid moves from the second U-turn passage to the back pressure space, and the fluid pressure in the back pressure space rises. At this time, the fluid moves from the back pressure space to the valve chamber through the communication passage, and the fluid pressure in the back pressure space gradually decreases. Subsequently, when the fluid pressure in the second U-turn passage decreases due to the pulsation of the high-pressure fluid, the fluid pressure in the back pressure space rises relatively from the fluid pressure in the second U-turn passage, and the pressure equalizing hole closes. The movement of fluid from the 2U turn passage to the back pressure space is restricted. Therefore, the responsiveness of the pressure relief valve body to the pulsation can be effectively improved.

In the present invention, the straight valve body further has a straight valve body slidably arranged in the axial direction between the first valve seat and the second valve seat, and the straight valve body is slid together with the U-turn valve body. A straight that communicates one of the plurality of ports provided in the first valve seat and one of the plurality of ports provided in the second valve seat. It is preferable to have a passage. By doing so, the fluid can flow smoothly between the ports communicated by the straight passage.

In the present invention, it is preferable that the compression coil spring is arranged between the first valve body portion and the second valve body portion. By doing so, the first valve body portion can be reliably pressed by the first valve seat, and the second valve body portion can be reliably pressed by the second valve seat, and valve leakage can be suppressed more effectively.

According to the present invention, valve leakage due to fluid pulsation can be effectively suppressed.

It is sectional drawing of the flow path switching valve which concerns on one Embodiment of this invention. It is sectional drawing which shows the other state of the flow path switching valve of FIG. It is an enlarged sectional view of the valve body in the flow path switching valve of FIG. 1 and the vicinity thereof. It is a figure explaining the valve body which the flow path switching valve of FIG. 1 has. It is sectional drawing of the valve body which the flow path switching valve of FIG. 1 has. It is a figure which shows the structure of the modification of the flow path switching valve of FIG. It is a figure which shows the U-turn valve body which the flow path switching valve of FIG. 6 has. It is sectional drawing of the conventional flow path switching valve.

Hereinafter, the flow path switching valve according to the embodiment of the present invention will be described with reference to FIGS. 1 to 7.

The flow path switching valve of this embodiment is a six-way switching valve and is used in a heat pump type heating / cooling system such as a room air conditioner or a car air conditioner to switch the flow direction of the refrigerant as a fluid according to the switching of the heating / cooling operation. ..

1 and 2 are cross-sectional views of a flow path switching valve according to an embodiment of the present invention. FIG. 1 shows a state in which the valve body unit is in the first stop position (stop position during cooling operation). FIG. 2 shows a state in which the valve body unit is in the second stop position (stop position during heating operation). FIG. 3 is an enlarged cross-sectional view of the valve body unit and its vicinity in the flow path switching valve of FIG. FIG. 4 is a diagram illustrating a valve body included in the flow path switching valve of FIG. 4 (a) is a front view, FIG. 4 (b) is a plan view, and FIG. 4 (c) is a plan view of the second valve body portion. FIG. 5 is a cross-sectional view of a valve body included in the flow path switching valve of FIG. 5 (a) is a cross-sectional view taken along the axis L direction, and FIGS. 5 (b) and 5 (c) are enlarged cross-sectional views of the inside of the alternate long and short dash line of FIG. 5 (a). Indicates a closed state and a pressure equalizing hole opened. FIG. 6 is a diagram showing a configuration of a modified example of the flow path switching valve of FIG. 1, and is an enlarged cross-sectional view of the valve body unit and its vicinity. FIG. 7 is a view of the U-turn valve body included in the flow path switching valve of FIG. 6 as viewed from the second valve seat side. In FIGS. 1 to 3, 5 (c), and 6, the thick arrow schematically shows an example of the flow of the refrigerant.

As shown in FIGS. 1 to 3, the flow path switching valve 1 of this embodiment has a valve housing 10, a valve body unit 18, a piston portion 50, and a pilot portion 60.

The valve housing 10 is formed in a cylindrical shape. The axis of the valve housing 10 coincides with the axis L. The lid member 11 is fixed to one end of the valve housing 10 (the right end in FIGS. 1 and 2), and the lid member 12 is fixed to the other end (the left end in FIGS. 1 and 2). A first valve seat 13 and a second valve seat 15 are arranged inside the valve housing 10.

The first valve seat 13 is fixed to the inner peripheral surface of the valve housing 10. The first valve seat 13 has a first valve seat surface 14. The first valve seat surface 14 is provided with circular ports pB, pA, and pF that are sequentially arranged in the L direction of the axis from the right side to the left side in FIGS. 1 and 2. Circular tubular pipe joints B, A, and F penetrating the valve housing 10 are connected to the ports pB, pA, and pF, respectively.

The second valve seat 15 is fixed to the inner peripheral surface of the valve housing 10. The first valve seat 13 and the second valve seat 15 face each other in a direction orthogonal to the axis L. The facing direction between the first valve seat 13 and the second valve seat 15 is simply referred to as "opposing direction". The second valve seat 15 has a second valve seat surface 16. The second valve seat surface 16 is provided with circular ports pC, pD, and pE that are sequentially arranged in the L direction of the axis from the right side to the left side in FIGS. 1 and 2. The ports pC, pD, and pE face the ports pB, pA, and pF of the first valve seat 13. Circular tubular pipe joints C, D, and E penetrating the valve housing 10 are connected to the ports pC, pD, and pE, respectively.

The second valve seat surface 16 of the second valve seat 15 is provided with a pressure equalizing groove 16a as a pressure equalizing path extending from the port pC to the end portion of the second valve seat surface 16 on the lid member 11 side. The pressure equalizing groove 16a communicates the port pC with the valve chamber 59, which will be described later, when the port pC is covered with the U-turn valve body 20. Instead of the pressure equalizing groove 16a, a through hole may be provided as a pressure equalizing path that penetrates the second valve seat 15 and communicates the port pC and the valve chamber 59. High pressure refrigerant flows in the port pC. That is, the second valve seat 15 may be provided with a pressure equalizing path for communicating the port through which the highest pressure refrigerant flows among the plurality of ports provided in the second valve seat 15 and the valve chamber. ..

In this embodiment, the pipe joint C connected to the port pC is connected to the discharge portion of the compressor of the heat pump type heating / cooling system, and the high pressure refrigerant flows. The pipe joint F connected to the port pF is connected to the suction portion of the compressor, and the low pressure refrigerant flows.

The valve body unit 18 has a separate U-turn valve body 20 and a straight valve body 30, respectively.

The U-turn valve body 20 and the straight valve body 30 are slidably arranged in the axis L direction between the first valve seat 13 and the second valve seat 15. The U-turn valve body 20 and the straight valve body 30 are integrally held by a bracket 53 of a piston portion 50, which will be described later.

As shown in FIGS. 4 and 5, the U-turn valve body 20 includes a first valve body portion 21, a second valve body portion 22, a pressure release valve body 24, a sealing member 25, and side plates 26 and 26. And have.

The first valve body portion 21 is made of, for example, a synthetic resin, and is formed in a substantially rectangular parallelepiped shape. The first valve body portion 21 is arranged on the first valve seat 13 side. The end surface of the first valve body portion 21 on the first valve seat 13 side is in contact with the first valve seat surface 14, and the end surface is a concave portion having a substantially semi-elliptical sphere (or a shape obtained by halving an oval sphere). A first U-turn passage 28 is provided. An annular wall portion 21a is provided at an end portion of the first valve body portion 21 on the second valve seat 15 side.

The second valve body portion 22 is made of, for example, a synthetic resin, and is formed in a substantially quadrangular frustum shape that decreases stepwise from the second valve seat 15 side to the first valve seat 13 side. The second valve body portion 22 is arranged on the second valve seat 15 side. The end portion 22a on the first valve seat 13 side of the second valve body portion 22 is fitted inside the annular wall portion 21a of the first valve body portion 21. The end surface of the second valve body portion 22 on the second valve seat 15 side is in contact with the second valve seat surface 16, and the end surface is a concave portion having a substantially semi-elliptical sphere (or a shape obtained by halving an oval sphere). A second U-turn passage 29 is provided.

An accommodating portion 22b, which is a circular hole for accommodating the pressure relief valve body 24, is provided on the end surface of the second valve body portion 22 on the first valve seat 13 side. A washer 22c for holding the pressure relief valve body 24 to the accommodating portion 22b is attached to the opening of the accommodating portion 22b. In this embodiment, the inner edge of the washer 22c is formed in a substantially star shape. Further, the second valve body portion 22 is provided with a pressure equalizing hole 22d penetrating from the bottom surface of the accommodating portion 22b to the second U-turn passage 29. The pressure equalizing hole 22d communicates the second U-turn passage 29 with the back pressure space 27, which will be described later.

A back pressure space 27 is provided between the first valve body portion 21 and the second valve body portion 22. The back pressure space 27 is a closed space surrounded by the periphery, and is partitioned from the valve chamber 59. The back pressure space 27 is communicated with the valve chamber 59 by a communication passage 21b provided in the first valve body portion 21 and a through hole 26a provided in one side plate 26. A communication passage connecting the back pressure space 27 and the valve chamber 59 may be provided in the second valve body portion 22.

In this embodiment, the flow path area of the communication passage 21b (that is, the cross-sectional area orthogonal to the flow direction of the refrigerant) is smaller than the flow path area of the pressure equalizing hole 22d.

The pressure release valve body 24 is made of metal, for example, and is formed in a spherical shape. The pressure release valve body 24 is housed in the accommodating portion 22b of the second valve body portion 22 so as to be movable in the vertical direction in FIG. When the refrigerant pressure in the back pressure space 27 rises above the refrigerant pressure in the second U-turn passage 29, the pressure release valve body 24 moves downward and hits the bottom surface of the accommodating portion 22b to close the pressure equalizing hole 22d. When the refrigerant pressure in the second U-turn passage 29 rises above the refrigerant pressure in the back pressure space 27, the pressure release valve body 24 moves upward and hits the washer 22c to open the pressure equalizing hole 22d. In a state where the pressure release valve body 24 abuts on the washer 22c, a gap through which the refrigerant can flow is formed between the pressure release valve body 24 and the washer 22c. The pressure relief valve body 24 moves upward and downward according to the refrigerant pressure of the second U-turn passage 29 and the back pressure space 27, allowing the movement of the refrigerant from the second U-turn passage 29 to the back pressure space 27 and back pressure. The pressure equalizing hole 22d is opened and closed so as to restrict the movement of the refrigerant from the pressure space 27 to the second U-turn passage 29.

The sealing member 25 is, for example, an O-ring made of an elastic member. The sealing member 25 is arranged so as to be sandwiched between the inner peripheral surface of the annular wall portion 21a of the first valve body portion 21 and the outer peripheral surface of the end portion 22a on the first valve seat 13 side of the second valve body portion 22. Has been done. The U-turn valve body 20 is configured such that the projected area Sb projected in the opposite direction with respect to the outer shape of the sealing member 25 is larger than the opening area Sa of the second U-turn passage 29. By doing so, the second valve body portion 22 can always be pressed against the second valve seat surface 16 by the pressure received from the refrigerant.

The side plates 26 and 26 are made of metal and are formed in a flat plate shape. The side plates 26, 26 are arranged so as to sandwich the first valve body portion 21 and the second valve body portion 22 in the axis L direction. By arranging the metal side plates 26, 26 having high rigidity, the bracket 53 can push the portion of the first valve body portion 21 near the first valve seat 13 via the side plates 26, 26. Therefore, as compared with the configuration of pushing the portion of the first valve body portion 21 away from the first valve seat 13, it is more effective that the first valve body portion 21 is lifted from the first valve seat surface 14 at the time of sliding. It can be suppressed and the durability can be increased. Similarly, the bracket 53 can push the portion of the second valve body portion 22 near the second valve seat 15 via the side plates 26, 26. Therefore, it is more effective that the second valve body portion 22 is lifted from the second valve seat surface 16 at the time of sliding, as compared with the configuration of pushing the portion of the second valve body portion 22 away from the second valve seat 15. It can be suppressed and the durability can be increased. In addition, it is possible to suppress the generation of abnormal noise caused by stick slip.

Further, in the U-turn valve body 20, a spring member 80 composed of a plurality of compression coil springs is arranged between the first valve body portion 21 and the second valve body portion 22. One end of the spring member 80 is arranged in the coil spring assembly portion 81 which is a circular recess provided in the first valve body portion 21. The other end of the spring member 80 is arranged in the coil spring assembly portion 82 which is a circular recess provided in the second valve body portion 22. A force for pulling the first valve body portion 21 and the second valve body portion 22 away from each other in the opposite direction is applied by the plurality of spring members 80, and the first valve body portion 21 is pressed against the first valve seat surface 14 to obtain the first valve body portion 21. The two-valve body portion 22 is pressed against the second valve seat surface 16.

As shown in FIG. 3, the straight valve body 30 includes a cylindrical outer cylinder member 31, a cylindrical male member 32, a cylindrical female member 33, an O-ring 34, and a spring member 35. have. A male member 32 is inserted at the end of the outer cylinder member 31 on the first valve seat 13 side. A female member 33 is inserted at the end of the outer cylinder member 31 on the second valve seat 15 side. The male member 32 and the female member 33 are fitted in the outer cylinder member 31, and are sealed between each other by an O-ring 34. The male member 32 and the female member 33 form a straight passage 36. A spring member 35 made of a compression coil spring is arranged between the male member 32 and the female member 33. The male member 32 is pressed against the first valve seat surface 14 by the spring member 35, and the female member 33 is pressed against the second valve seat surface 16.

In this embodiment, the outer cylinder member 31 is made of metal, and the male member 32 and the female member 33 are made of synthetic resin. By making the outer cylinder member 31 made of a highly rigid metal, the bracket 53 can push the portion of the male member 32 near the first valve seat 13 via the outer cylinder member 31. Therefore, as compared with the configuration of pushing the portion of the male member 32 away from the first valve seat 13, it is possible to more effectively suppress the male member 32 from rising from the first valve seat surface 14 at the time of sliding, and it is durable. It can enhance the sex. Similarly, the bracket 53 can push the portion of the female member 33 closer to the second valve seat 15 via the outer cylinder member 31. Therefore, as compared with the configuration of pushing the portion of the female member 33 away from the second valve seat 15, it is possible to more effectively prevent the female member 33 from rising from the second valve seat surface 16 when sliding, and it is durable. It can enhance the sex. In addition, it is possible to suppress the generation of abnormal noise caused by stick slip.

The valve body unit 18 is positioned at the first stop position when slid toward one end of the valve housing 10 along the axis L direction on the first valve seat surface 14 and the second valve seat surface 16, and the valve is valved. When it is slid toward the other end of the housing 10, it is positioned at the second stop position.

When the valve body unit 18 is in the first stop position, the first U-turn passage 28 communicates the port pB and the port pA of the plurality of ports pB, pA, pF provided in the first valve seat 13. .. The second U-turn passage 29 communicates the port pC and the port pD among the plurality of ports pC, pD, and pE provided in the second valve seat 15. The straight passage 36 communicates the port pF provided in the first valve seat 13 and the port pE provided in the second valve seat 15. The pressure equalizing groove 16a communicates the port pC with the valve chamber 59.

When the valve body unit 18 is in the second stop position, the first U-turn passage 28 communicates the port pA and the port pF of the plurality of ports pB, pA, pF provided in the first valve seat 13. .. The second U-turn passage 29 communicates the port pD and the port pE among the plurality of ports pC, pD, and pE provided in the second valve seat 15. The valve chamber 59 communicates the port pB provided in the first valve seat 13 and the port pC provided in the second valve seat 15.

The piston portion 50 has a first piston 51, a second piston 52, and a bracket 53.

The first piston 51 is arranged between the lid member 11 provided at one end of the valve housing 10 and the first valve seat 13 and the second valve seat 15. A first operating chamber 57 is formed between the first piston 51 and the lid member 11. The second piston 52 is arranged between the lid member 12 provided at the other end of the valve housing 10 and the first valve seat 13 and the second valve seat 15. A second operating chamber 58 is formed between the second piston 52 and the lid member 12. A valve chamber 59 is formed between the first piston 51 and the second piston 52. In the valve chamber 59, a first valve seat 13, a second valve seat 15, and a valve body unit 18 are arranged.

The metal bracket 53 integrally has a bracket body 54 formed in a rectangular plate shape and piston mounting pieces 55 and 56 provided at both ends of the bracket body 54. The bracket body 54 is provided with a substantially rectangular U-turn valve body holding hole 54a into which the U-turn valve body 20 is inserted, and a circular straight valve body holding hole 54b into which the straight valve body 30 is inserted. .. The first piston 51 is attached to the piston attachment piece 55. A second piston 52 is attached to the piston attachment piece 56. The bracket 53 connects the first piston 51 and the second piston 52.

The pilot unit 60 is composed of, for example, a solenoid type flow path switching valve. The pilot unit 60 switches the connection between the first operating chamber 57 and the second operating chamber 58, and the pipe joint C and the pipe joint F by switching the connection of the thin tubes 71 to 74, and switches the connection between the first operating chamber 57 and the second operating chamber 57. 2 The refrigerant pressure in the working chamber 58 is controlled. As a result, the piston portion 50 is moved to one end side or the other end side of the valve housing 10 due to the difference in the refrigerant pressure in the first operating chamber 57 and the second operating chamber 58. As the piston portion 50 moves, the valve body unit 18 held by the bracket 53 is slid in the axis L direction and is positioned at the first stop position shown in FIG. 1 or the second stop position shown in FIG.

Next, an example of the operation of the flow path switching valve 1 described above will be described.

During the cooling operation, the flow path switching valve 1 connects the thin tube 71 and the thin tube 72 by the pilot unit 60, and connects the thin tube 73 and the thin tube 74. As a result, the pipe joint C and the second operating chamber 58 are connected, and the pipe joint F and the first operating chamber 57 are connected, the refrigerant pressure in the first operating chamber 57 becomes low, and the second operating chamber 58 Refrigerant pressure increases. The piston portion 50 moves toward one end of the valve housing 10 due to the difference in the refrigerant pressure, and the valve body unit 18 is positioned at the first stop position as shown in FIG.

At the first stop position, the first U-turn passage 28 communicates the port pB and the port pA, and the medium pressure refrigerant flows through the first U-turn passage 28. The second U-turn passage 29 communicates the port pC and the port pD, and the high-pressure refrigerant flows through the second U-turn passage 29. The straight passage 36 communicates the port pE and the port pF, and the low pressure refrigerant flows through the straight passage 36. The pressure equalizing groove 16a communicates the port pC with the valve chamber 59, and a high-pressure refrigerant is introduced into the valve chamber 59. A high-pressure refrigerant is introduced from the valve chamber 59 into the back pressure space 27 through the through hole 26a and the communication passage 21b. At this time, in the U-turn valve body 20, when the pressure of the high-pressure refrigerant in the second U-turn passage 29 rises due to the pulsation of the high-pressure refrigerant, the pressure equalizing hole 22d opens and the high-pressure refrigerant flows from the second U-turn passage 29 to the back pressure space 27. Can be moved to to relieve pressure. The first valve body portion 21 is pressed against the first valve seat surface 14 by the differential pressure between the pressure received from the medium pressure refrigerant flowing through the first U-turn passage 28 and the pressure received from the high pressure refrigerant introduced into the back pressure space 27. Further, the first valve body portion 21 is pressed against the first valve seat surface 14 and the second valve body portion 22 is pressed against the second valve seat surface 16 by the plurality of spring members 80.

Further, during the heating operation, the flow path switching valve 1 connects the thin tube 71 and the thin tube 74 by the pilot unit 60, and connects the thin tube 73 and the thin tube 72. As a result, the pipe joint C and the first operating chamber 57 are connected, and the pipe joint F and the second operating chamber 58 are connected, the refrigerant pressure in the first operating chamber 57 increases, and the second operating chamber 58 Refrigerant pressure is low. The piston portion 50 moves to the other end side of the valve housing 10 due to the difference in the refrigerant pressure, and the valve body unit 18 is positioned at the second stop position as shown in FIG.

At the second stop position, the first U-turn passage 28 communicates the port pA and the port pF, and the low-pressure refrigerant flows through the first U-turn passage 28. The second U-turn passage 29 communicates the port pD and the port pE, and the medium-pressure refrigerant flows through the second U-turn passage 29. The valve chamber 59 communicates the port pC and the port pB, and a high-pressure refrigerant flows through the valve chamber 59. A high-pressure refrigerant is introduced from the valve chamber 59 into the back pressure space 27 through the through hole 26a and the communication passage 21b. At this time, the first valve body portion 21 is pressed against the first valve seat surface 14 by the differential pressure between the pressure received from the low pressure refrigerant flowing through the first U-turn passage 28 and the pressure received from the high pressure refrigerant introduced into the back pressure space 27. Be done. Further, the second valve body portion 22 is pressed against the second valve seat surface 16 by the differential pressure between the pressure received from the medium pressure refrigerant flowing through the second U-turn passage 29 and the pressure received from the high pressure refrigerant introduced into the back pressure space 27. Be done. Further, the plurality of spring members 80 press the first valve body portion 21 against the first valve seat surface 14 and the second valve body portion 22 against the second valve seat surface 16.

In this way, the first valve body portion 21 is pressed against the first valve seat 13 and the second valve body portion 22 is pressed against the second valve seat 15 at both the first stop position and the second stop position. Can be done. Further, when the high-pressure refrigerant flows through the second U-turn passage 29, the pressure increased by the pulsation of the high-pressure refrigerant can be released from the second U-turn passage 29 to the back pressure space 27.

From the above, according to the flow path switching valve 1 of the present invention, in a state where the high pressure refrigerant flows in the second U turn passage 29 and the high pressure refrigerant is introduced into the valve chamber 59, the pulsation of the high pressure refrigerant causes the inside of the second U turn passage 29. When the refrigerant pressure of the above increases, the pressure equalizing hole 22d opens and the refrigerant moves from the second U-turn passage 29 to the back pressure space 27. Therefore, the refrigerant pressure in the second U-turn passage 29 can be released, and valve leakage due to the pulsation of the refrigerant can be effectively suppressed. Further, in a state where the medium pressure refrigerant flows in the second U turn passage 29 and the high pressure refrigerant flows in the valve chamber 59, the pressure equalizing hole 22d is closed and the movement of the refrigerant from the back pressure space 27 to the second U turn passage 29 is restricted. To. As a result, the second valve body portion 22 is pressed against the second valve seat 15 by the differential pressure between the pressure received from the medium pressure refrigerant in the second U-turn passage 29 and the pressure received from the high pressure refrigerant in the back pressure space 27. Therefore, it is possible to suppress the formation of a gap between the second valve body portion 22 and the second valve seat 15, and effectively suppress valve leakage.

Further, the first valve body portion 21 is provided with a communication passage 21b that connects the valve chamber 59 and the back pressure space 27. The flow path area of the communication passage 21b is smaller than the flow path area of the pressure equalizing hole 22d. By doing so, the refrigerant pressure in the back pressure space 27 changes more slowly. That is, when the refrigerant pressure in the second U-turn passage 29 rises due to the pulsation of the high-pressure refrigerant, the pressure equalizing hole 22d opens and the refrigerant moves from the second U-turn passage 29 to the back pressure space 27, and the refrigerant pressure in the back pressure space 27. Rise. At this time, the refrigerant moves from the back pressure space 27 to the valve chamber 59 through the communication passage 21b, and the refrigerant pressure in the back pressure space 27 gradually decreases. Subsequently, when the refrigerant pressure in the second U-turn passage 29 decreases due to the pulsation of the high-pressure refrigerant, the refrigerant pressure in the back pressure space 27 rises relatively from the refrigerant pressure in the second U-turn passage 29, and the pressure equalizing hole 22d Is closed and the movement of the refrigerant from the second U-turn passage 29 to the back pressure space 27 is restricted. Therefore, the responsiveness of the pressure relief valve body 24 to the pulsation can be effectively improved.

Further, it further has a straight valve body 30 slidably arranged in the axis L direction between the first valve seat 13 and the second valve seat 15. The straight valve body 30 is configured to slide together with the U-turn valve body 20. The straight valve body 30 has a straight passage 36 for communicating the port pF provided in the first valve seat 13 and the port pE provided in the second valve seat 15. By doing so, the refrigerant can flow smoothly between the ports pF and pE communicated by the straight passage 36.

Further, a plurality of spring members 80 are arranged between the first valve body portion 21 and the second valve body portion 22. By doing so, the first valve body portion 21 can be reliably pressed by the first valve seat 13, and the second valve body portion 22 can be reliably pressed by the second valve seat 15, so that valve leakage is more effective. Can be suppressed.

In the above-described embodiment, the second valve seat 15 is provided with a pressure equalizing groove 16a for communicating the port pC and the valve chamber 59, but the configuration is not limited to this. Instead of the pressure equalizing groove 16a provided in the second valve seat 15, for example, as shown in FIGS. 6 and 7, the second valve body portion 22 is provided with a pressure equalizing groove 22f as a pressure equalizing path. May be good. The pressure equalizing groove 22f is provided on the end surface 22e on the second valve seat 15 side of the second valve body portion 22. In this configuration, the chamfered portion (tapered surface) of the port pC is enlarged, and the port pC is passed between the pressure equalizing groove 22f and the chamfered portion of the port pC only when the valve body unit 18 is in the first stop position. And the valve chamber 59 are communicated with each other. That is, the pressure equalizing passage is provided in the second valve seat 15 or the second valve body portion 22, and the port through which the highest pressure fluid flows among the plurality of ports provided in the second valve seat 15 and the valve chamber 59. Anything that communicates with each other.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. As long as the gist of the present invention is not contrary to the above-mentioned embodiments, those skilled in the art appropriately adding, deleting, or changing the design, or combining the features of the examples as appropriate are also present inventions. Is included in the range of.

1 ... Flow path switching valve, 10 ... Valve housing, 11, 12 ... Lid member, 13 ... First valve seat, 14 ... First valve seat surface, 15 ... Second valve seat, 16 ... Second valve seat surface, 16a ... pressure equalizing groove, 18 ... valve body unit, 20 ... U-turn valve body, 21 ... first valve body portion, 21a ... annular wall portion, 21b ... communication passage, 22 ... second valve body portion, 22a ... end portion, 22b ... Accommodating part, 22c ... Washer, 22d ... Pressure equalizing hole, 24 ... Pressure relief valve body, 25 ... Sealing member, 26 ... Side plate, 26a ... Through hole, 27 ... Back pressure space, 28 ... First U-turn passage, 29 ... 2nd U-turn passage, 30 ... straight valve body, 31 ... outer cylinder member, 32 ... male member, 33 ... female member, 34 ... O-ring, 35 ... spring member, 50 ... piston part, 51 ... first Piston, 52 ... 2nd piston, 53 ... Bracket, 54 ... Bracket body, 55, 56 ... Piston mounting piece, 57 ... 1st operating chamber, 58 ... 2nd operating chamber, 59 ... Valve chamber, 60 ... Pilot part, 71 , 72, 72, 74 ... Thin tube, 80 ... Spring member, 81, 82 ... Coil spring assembly, pA, pB, pC, pD, pE, pF ... Port, A, B, C, D, E, F ... Pipe fitting, L ... Axis line

Claims (3)

A cylindrical valve housing provided with a valve chamber, a first valve seat arranged in the valve chamber, a second valve seat arranged in the valve chamber facing the first valve seat, and the first valve seat. A flow path switching valve having a U-turn valve body slidably arranged in the axial direction between one valve seat and the second valve seat.
The U-turn valve body has a first valve body portion arranged on the first valve seat side and a second valve body portion arranged on the second valve seat side.
The first valve body portion is provided with a first U-turn passage for communicating two ports out of a plurality of ports provided on the first valve seat.
The second valve body portion is provided with a second U-turn passage for communicating two ports out of a plurality of ports provided on the second valve seat.
A back pressure space communicating with the valve chamber is provided between the first valve body portion and the second valve body portion.
The second valve body portion allows the pressure equalizing hole that communicates the second U-turn passage and the back pressure space, and the movement of fluid from the second U-turn passage to the back pressure space, and allows the back pressure space. It has a pressure relief valve body that opens and closes the pressure equalizing hole so as to restrict the movement of the fluid from the second U-turn passage to the second U-turn passage.
The first valve body portion is provided with a communication passage that communicates the valve chamber and the back pressure space.
A flow path switching valve characterized in that the flow path area of the communication passage is smaller than the flow path area of the pressure equalizing hole . Further having a straight valve body slidably arranged in the axial direction between the first valve seat and the second valve seat.
The straight valve body is configured to slide together with the U-turn valve body, and is provided in one of the plurality of ports provided in the first valve seat and the second valve seat. The flow path switching valve according to claim 1 , which has a straight passage that communicates with one of a plurality of ports. The flow path switching valve according to claim 1 or 2 , wherein a compression coil spring is arranged between the first valve body portion and the second valve body portion.

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