Flow path switching valve

Abstract

Provided is a flow path switching valve capable of suppressing noise even without reducing the pressure of refrigerant introduced into a valve chamber. An inner space of a valve body (20) of a flow path switching valve (1) is divided into a valve chamber (13), a first working chamber (11), and a second working chamber (12). A pilot valve (110) is configured to switch between a first connection passage connecting an outlet port (33) of a valve seat (30) and the first working chamber (11) and a second connection passage connecting the outlet port (33) and the second working chamber (12). When a minimum diameter of a first throttle passage (57) of a first piston (50) is Da, a minimum diameter of the first connection passage is Db, and a differential pressure between the valve chamber (13) and the first working chamber (11) when the outlet port (33) and the first working chamber (11) are connected by the first connection passage is ΔP, the flow path switching valve satisfies the following formula (1): Rmin ≤ Da / Db …… (1), where Rmin = (ΔP + (21.65)) / 30.27 when 0.2 MPa ≤ ΔP ≤ 10.0 MPa.

Description

Technical Field

[0001] This invention relates to a pilot-operated flow path switching valve. Background Technology

[0002] Patent Document 1 discloses an example of a conventional flow path switching valve. This flow path switching valve is incorporated, for example, into the refrigeration cycle of an air conditioner and operates when the refrigerant flow path is switched. The flow path switching valve has a four-way valve as the main valve and a three-way switching valve as the pilot valve.

[0003] The four-way valve has a cylindrical valve body. Both ends of the valve body are closed by cap components. Inside the valve body are a valve seat, a valve core, a first piston, and a second piston. The valve seat is positioned between the first and second pistons. The internal space of the valve body is divided into a valve chamber between the first and second pistons, a first working chamber between the first piston and one of the cap components, and a second working chamber between the second piston and the other cap component. The first and second pistons are connected to each other by a connecting body. The connecting body fits into the valve core. An inlet port is formed on the valve body opposite the valve seat. A first port, an outlet port, and a second port are formed on the valve seat surface. The inlet port allows high-pressure refrigerant to flow, and the outlet port allows low-pressure refrigerant to flow. The valve core slides on the valve seat surface to connect the first port and the outlet port, or to connect the second port and the outlet port.

[0004] A four-way valve is connected to a three-way switching valve. The three-way switching valve switches between a connection path (first connection path) connecting the outlet port and the first working chamber, and a connection path (second connection path) connecting the outlet port and the second working chamber. The valve chamber is connected to the inlet port. When switched to the first connection path by the three-way switching valve, the first piston and the second piston move toward one of the cover parts due to the differential pressure between the valve chamber and the first working chamber, and the valve core slides toward one of the cover parts. The first port is connected to the outlet port via the valve core, and the inlet port is connected to the second port via the valve chamber. Alternatively, when switched to the second connection path by the three-way switching valve, the first piston and the second piston move toward the other cover part due to the differential pressure between the valve chamber and the second working chamber, and the valve core moves toward the other cover part. The second port is connected to the outlet port via the valve core, and the inlet port is connected to the first port via the valve chamber. The first piston has a throttling path connecting the valve chamber and the first working chamber. The second piston has a throttling path connecting the valve chamber and the second working chamber. The four-way valve allows refrigerant to flow between the valve chamber and the first working chamber, and also between the valve chamber and the second working chamber, through various flow paths.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Utility Model Application Publication No. 62-39074

[0008] The technical problem that the invention aims to solve

[0009] The aforementioned four-way valve raises the following concern: noise is generated due to refrigerant flow when switching the connection between the first and second ports as the valve core moves. Noise can be suppressed by reducing the compressor speed, thereby lowering the pressure of the refrigerant introduced into the valve chamber from the inlet port and slowing down the sliding of the valve core (i.e., the movement speed of the first and second pistons). However, a problem arises: control is required to reduce the compressor speed before the flow path switching via the four-way valve and to increase the compressor speed after the switching, complicating the control of the refrigeration cycle. Furthermore, reducing the compressor speed requires a relatively long period of approximately 1 to 3 minutes, and increasing the compressor speed also requires a similar amount of time. Therefore, there is a need for preparation time before and after the flow path switching of the four-way valve. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide a flow path switching valve that can suppress noise even without reducing the pressure of the refrigerant introduced into the valve chamber.

[0011] Technical means for solving technical problems

[0012] The inventors of this invention focused on the throttling path of the first and second pistons of the flow path switching valve and the connecting path that connects the outlet port to the working chamber. They repeatedly conducted experiments related to flow path switching using multiple flow path switching valves with different ratios of the minimum diameter of the throttling path to the minimum diameter of the connecting path. After in-depth research into the experimental results, the inventors discovered the relationship between the ratio of the minimum diameter of the throttling path to the minimum diameter of the connecting path, the differential pressure between the valve chamber and the working chamber, and the time required for the first and second pistons to move during flow path switching (flow path switching time), thus completing this invention.

[0013] To achieve the above objectives, one aspect of the flow path switching valve of the present invention is a flow path switching valve having a main valve and a pilot valve. The main valve comprises: a valve body, which is a cylindrical shape with one end and the other end closed; a valve seat disposed inside the valve body; a first piston disposed between one end of the valve body and the valve seat; a second piston disposed between the other end of the valve body and the valve seat; and a main valve core disposed on a valve seat surface of the valve seat and sliding axially with the first piston and the second piston in the valve body. The inner space of the valve body is divided into a valve chamber between the first piston and the second piston; a first working chamber between one end of the valve body and the first piston; and a second working chamber between the other end of the valve body and the second piston. The valve body has an inlet port connected to the valve chamber, and the valve seat has an outlet port connected to the U-shaped bend passage of the main valve core. The first piston has a first flow path connecting the valve chamber and the first working chamber, and the second piston has a second flow path connecting the valve chamber and the second working chamber. The pilot valve is configured to switch between the first connection path connecting the outlet port and the first working chamber and the second connection path connecting the outlet port and the second working chamber. When the minimum diameter of the first flow path is set to Da, the minimum diameter of the first connection path is set to Db, and the differential pressure between the valve chamber and the first working chamber when the outlet port and the first working chamber are connected through the first connection path is set to ΔP, the flow path switching valve satisfies the following formula (1):

[0014] Rmin≤Da / Db……(1),

[0015] in,

[0016] When 0.2MPa≤ΔP≤10.0MPa, Rmin=(ΔP+(21.65)) / 30.27.

[0017] In this invention, it is preferred that the following formula (1A) is satisfied.

[0018] Rmin≤Da / Db≤Rmax……(1A),

[0019] in,

[0020] When 0.2MPa≤ΔP≤10.0MPa,

[0021] Rmin=(ΔP+(21.65)) / 30.27;

[0022] When 0.2MPa≤ΔP<1.0MPa,

[0023] Rmax = (ΔP + (11.80)) / 11.43;

[0024] When 1.0 MPa ≤ ΔP < 2.0 MPa,

[0025] Rmax = (ΔP + (12.97)) / 12.47;

[0026] When 2.0 MPa ≤ ΔP < 3.0 MPa,

[0027] Rmax = (ΔP + (5.62)) / 6.35;

[0028] When 3.0 MPa ≤ ΔP < 4.0 MPa,

[0029] Rmax = (ΔP + (2.48)) / 4.04;

[0030] When 4.0 MPa ≤ ΔP < 5.0 MPa,

[0031] Rmax = (ΔP + (0.90)) / 3.05;

[0032] When 5.0 MPa ≤ ΔP < 6.0 MPa,

[0033] Rmax = (ΔP + (-1.23)) / 1.95;

[0034] When 6.0 MPa ≤ ΔP < 7.0 MPa,

[0035] Rmax = (ΔP + (-3.28)) / 1.11;

[0036] When 7.0 MPa ≤ ΔP < 8.0 MPa,

[0037] Rmax = (ΔP + (-5.22)) / 0.53;

[0038] When 8.0 MPa ≤ ΔP ≤ 10.0 MPa,

[0039] Rmax = (ΔP + (-5.99)) / 0.38.

[0040] In this invention, it is preferred that the following formula (1B) is satisfied.

[0041] Rmin≤Da / Db≤Rmax......(1B),

[0042] in,

[0043] When 0.2MPa≤ΔP≤10.0MPa,

[0044] Rmin=(ΔP+(21.65)) / 30.27;

[0045] When 0.2MPa≤ΔP<1.0MPa,

[0046] Rmax = (ΔP + (15.80)) / 16.00;

[0047] When 1.0MPa≤ΔP<2.0MPa,

[0048] Rmax = (ΔP + (14.41)) / 14.67;

[0049] When 2.0 MPa ≤ ΔP < 3.0 MPa,

[0050] Rmax = (ΔP + (6.96)) / 8.01;

[0051] When 3.0 MPa ≤ ΔP < 4.0 MPa,

[0052] Rmax = (ΔP + (3.56)) / 5.28;

[0053] When 4.0 MPa ≤ ΔP < 5.0 MPa,

[0054] Rmax = (ΔP + (1.85)) / 4.08;

[0055] When 5.0 MPa ≤ ΔP < 6.0 MPa,

[0056] Rmax = (ΔP + (-0.48)) / 2.69;

[0057] When 6.0 MPa ≤ ΔP < 7.0 MPa,

[0058] Rmax = (ΔP + (-2.73)) / 1.60;

[0059] When 7.0 MPa ≤ ΔP < 8.0 MPa,

[0060] Rmax = (ΔP + (-4.83)) / 0.81;

[0061] When 8.0 MPa ≤ ΔP ≤ 10.0 MPa,

[0062] Rmax = (ΔP + (-5.50)) / 0.64.

[0063] In this invention, preferably, the first piston and the second piston each have metal parts, the portion of the first flow path that becomes the minimum diameter is formed in a through hole of the metal part, and the portion of the second flow path that becomes the minimum diameter is formed in a through hole of the metal part.

[0064] In this invention, preferably, the minimum diameter of the second flow path is the same as the minimum diameter Da of the first flow path, and the minimum diameter of the second connecting passage is the same as the minimum diameter Db of the first connecting passage. When the minimum diameter of the second flow path is set to Da, the minimum diameter of the second connecting passage is set to Db, and the differential pressure between the valve chamber and the second working chamber when the outlet port is connected to the second working chamber through the second connecting passage is set to ΔP, the above formula (1) is satisfied.

[0065] The effects of the invention

[0066] According to the present invention, the ratio Da / Db of the minimum diameter Da of the first flow path of the first piston and the minimum diameter Db of the first connecting passage connecting the outlet port and the first working chamber satisfies the above formula (1). Therefore, the time required for the movement of the first and second pistons during flow path switching (flow path switching time) can be made a time capable of suppressing noise. Similarly, by ensuring that the ratio of the minimum diameter of the second flow path of the second piston and the minimum diameter of the second connecting passage connecting the outlet port and the second working chamber satisfies the above formula (1), the flow path switching time can also be made a time capable of suppressing noise. Therefore, the flow path switching valve of the present invention can suppress noise even without reducing the pressure of the refrigerant introduced into the valve chamber. Attached Figure Description

[0067] Figure 1 This is a cross-sectional view of a flow path switching valve according to an embodiment of the present invention.

[0068] Figure 2 It means Figure 1 A cross-sectional view of the flow path switching valve in other states.

[0069] Figure 3 It's enlarged. Figure 1 A cross-sectional view obtained from a portion of the main valve of the flow path switching valve.

[0070] Figure 4 It's enlarged. Figure 2 A cross-sectional view obtained from a portion of the main valve of the flow path switching valve.

[0071] Figure 5 It's enlarged. Figure 1 A cross-sectional view obtained from a portion of the pilot valve of a flow path switching valve.

[0072] Figure 6 It means Figure 1 A graph showing the relationship between the ratio of the minimum diameter of the first flow path to the minimum diameter of the first connecting passage in the flow path switching valve and the differential pressure between the valve chamber and the first working chamber.

[0073] Figure 7 It means in Figure 1 A graph showing the ratio of the minimum diameter of the first flow path to the minimum diameter of the first connecting passage in a flow path switching valve that enables noise suppression and shorter flow path switching time, and the range of differential pressure between the valve chamber and the first working chamber.

[0074] Figure 8 It means in Figure 1 A graph showing the ratio of the minimum diameter of the first flow path to the minimum diameter of the first connecting passage in a flow path switching valve that enables noise suppression and shorter flow path switching time, and the range of differential pressure between the valve chamber and the first working chamber.

[0075] Symbol Explanation

[0076] 1… Flow path switching valve, 10… Main valve, 11… First working chamber, 12… Second working chamber, 13… Valve chamber, 20… Valve body, 21… First cover component, 21a… First connection port, 22… Second cover component, 22a… Second connection port, 23… Inlet port, 30… Valve seat, 30a… Valve seat surface, 31… First port, 32… Second port, 33… Outlet port, 40… Main valve core, 41… U-shaped bend passage, 50… First piston 51, 52…circular plate, 53…leaf spring component, 53a…circular plate portion, 53b…spring plate, 53c…through hole, 54…shield, 54a…bottom wall portion, 54b…peripheral wall portion, 55…valve core support component, 55a…circular plate portion, 55b…protrusion, 56…valve core, 56a…base end, 56b…top end, 57…first flow path, 60…second piston, 61, 62…circular plate, 63…leaf spring component, 63a…circular plate portion, 6 3b…Spring plate, 63c…Through hole, 64…Gasket, 64a…Bottom wall, 64b…Peripheral wall, 65…Valve core support component, 65a…Circular plate, 65b…Protrusion, 66…Valve core, 66a…Base end, 66b…Top end, 67…Second flow path, 70…Connector, 71…Valve core fitting hole, 83…Inlet conduit, 91…First conduit, 92…Second conduit, 93…Outlet conduit, 110…Pilot valve, 120…Valve Main body, 121…cover component, 130…valve seat, 130a…valve seat surface, 131…first port, 132…second port, 133…general port, 140…pilot valve core, 141…U-shaped bend passage, 150…fixed iron core, 160…plunger, 161…plunger spring, 170…valve shaft, 191…first connecting pipe, 192…second connecting pipe, 193…general connecting pipe, C1…first connecting passage, C2…second connecting passage Detailed Implementation

[0077] The following is for reference Figures 1 to 8 An embodiment of the flow path switching valve of the present invention will be described.

[0078] Figure 1 , Figure 2 This is a cross-sectional view of a flow path switching valve according to an embodiment of the present invention. Figure 1 This indicates that the main valve core is in the first main valve core position. Figure 2 This indicates that the main valve core is in the second main valve core position. Figure 1 , Figure 2 The diagram illustrates the connection between the main valve and the pilot valve, with aa, bb, and cc connected respectively. Figure 3 It's enlarged. Figure 1 This is a cross-sectional view of a portion of the main valve of the flow path switching valve shown. Figure 3 It is a cross-sectional view obtained by magnifying the first piston of the main valve. Figure 4 It's enlarged. Figure 2 This is a cross-sectional view of a portion of the main valve of the flow path switching valve shown. Figure 4 It is a cross-sectional view obtained by magnifying the second piston of the main valve. Figure 5 It's enlarged. Figure 1 A cross-sectional view obtained from a portion of the pilot valve of a flow path switching valve. Figure 5 It is an enlarged cross-sectional view of the valve seat of the pilot valve. Figure 6 It means Figure 1 A graph showing the relationship between the ratio of the minimum diameter of the first flow path to the minimum diameter of the first connecting passage in the flow path switching valve and the differential pressure between the valve chamber and the first working chamber. Figure 7 , Figure 8 It means in Figure 1 A graph showing the ratio of the minimum diameter of the first flow path to the minimum diameter of the first connecting passage in a flow path switching valve that enables noise suppression and shorter flow path switching time, and the range of differential pressure between the valve chamber and the first working chamber. Figure 7 This indicates that the flow path switching time is in the range of 1.1 seconds to 60 seconds. Figure 8 This indicates that the flow path switching time is in the range of 1.1 seconds to 30 seconds.

[0079] like Figure 1 , Figure 2 As shown, the flow path switching valve 1 in this embodiment has a main valve 10 and a pilot valve 110.

[0080] The main valve 10 has a valve body 20, a valve seat 30, a main valve core 40, a first piston 50, a second piston 60, and a connecting body 70.

[0081] The valve body 20 has a cylindrical shape. The axial direction of the valve body 20 is parallel to... Figure 1 , Figure 2 The left and right directions are consistent. One end of the valve body 20 (in) Figure 1 , Figure 2The left end of the valve body 20 is closed by the first cover component 21. The other end of the valve body 20 (in the middle) is closed by the first cover component 21. Figure 1 , Figure 2 The valve body 20 (right end) is closed by a second cover component 22. The first cover component 21 has a first connection port 21a. The second cover component 22 has a second connection port 22a. The valve body 20 has an inlet port 23. The inlet port 23 is located at the axial center of the upper part of the valve body 20. An inlet conduit 83 is connected to the inlet port 23.

[0082] The valve seat 30 is disposed axially at the center of the lower part of the valve body 20, inside the valve body 20. The valve seat 30 has an upward-facing seat surface 30a. The valve seat 30 has a first port 31, an outlet port 33, and a second port 32 arranged sequentially from the first cover member 21 side to the second cover member 22 side. The first port 31, outlet port 33, and second port 32 open at the seat surface 30a. A first conduit 91 is connected to the first port 31. An outlet conduit 93 is connected to the outlet port 33. A second conduit 92 is connected to the second port 32. The valve body 20, the first cover member 21, the second cover member 22, and the valve seat 30 are made of metal, such as stainless steel.

[0083] The main valve core 40 has a generally semi-ellipsoidal shape. The main valve core 40 has a U-shaped bend passage 41 on its inner side. The U-shaped bend passage 41 is separated from the valve chamber 13, which will be described later. The main valve core 40 is disposed on the valve seat surface 30a. The main valve core 40 slides on the valve seat surface 30a and is positioned at the first main valve core position where the U-shaped bend passage 41 connects the first port 31 and the outlet port 33. Figure 1 The position of the main valve core 40 shown) and the second main valve core position that connects the second port 32 and the outlet port 33 via the U-shaped bend passage 41 (shown) Figure 2 (The position of the main valve core 40 is shown). The outlet port 33 is always connected to the U-shaped bend passage 41. The main valve core 40 is made of synthetic resin such as polyphenylene sulfide (PPS).

[0084] The first piston 50 is disposed inside the valve body 20 between the first cover component 21 and the valve seat 30. The first piston 50 is movable axially within the valve body 20. The first piston 50 divides the inner space of the valve body 20 axially. The first piston 50 has circular plates 51 and 52, a leaf spring component 53, a gasket 54, a valve core support component 55, a valve core 56, and a compression coil spring 58. The circular plates 51 and 52 are made of metal such as stainless steel. The outer diameter of the circular plate 51 is slightly smaller than the inner diameter of the valve body 20. The outer diameter of the circular plate 52 is smaller than the outer diameter of the circular plate 51. The leaf spring component 53 is a metal part. The leaf spring component 53 has a circular plate portion 53a and multiple spring plates 53b connected to the periphery of the circular plate portion 53a. The gasket 54 is made of synthetic resin such as polytetrafluoroethylene (PTFE). The gasket 54 has a circular tray shape. The gasket 54 has a circular plate-shaped bottom wall portion 54a and a peripheral wall portion 54b connected to the periphery of the bottom wall portion 54a. A leaf spring member 53 is disposed inside the gasket 54. The circular plate portion 53a of the leaf spring member 53 contacts the bottom wall portion 54a of the gasket 54. Circular plates 51 and 52 are fastened together by bolts (not shown), and the circular plate portion 53a of the leaf spring member 53 and the bottom wall portion 54a of the gasket 54 are held between the circular plates 51 and 52. A plurality of spring plates 53b of the leaf spring member 53 press the peripheral wall portion 54b of the gasket 54 from the inside to the outside. The peripheral wall portion 54b of the gasket 54 contacts the inner peripheral surface of the valve body 20. The valve core support member 55 is made of a metal such as brass. The valve core support member 55 has a circular plate portion 55a and a protrusion 55b. The circular plate portion 55a engages with the surface of the first cover member 21 side in the circular plate 51. A protrusion 55b is positioned at the center of the circular plate portion 55a. The valve core 56 is made of synthetic resin such as PPS. The valve core 56 has a cylindrical shape. The valve core 56 is supported by the protrusion 55b of the valve core support member 55, allowing it to move axially within the valve body 20. The base end portion 56a of the valve core 56 is positioned inside the protrusion 55b. The top end portion 56b of the valve core 56 protrudes outward from the protrusion 55b. The base end portion 56a of the valve core 56 is pressed against the gasket 54 by a compression coil spring 58. The top end portion 56b of the valve core 56 is formed into a generally conical shape. The valve core 56 opens and closes the first connection port 21a of the first cover member 21.

[0085] The first piston 50 has a first flow passage 57 extending from the first cover member 21 side to the valve seat 30 side. The first flow passage 57 has the smallest passage area in the through hole 53c formed in the leaf spring member 53. The diameter of the through hole 53c is the minimum diameter Da of the first flow passage 57.

[0086] The second piston 60 is disposed inside the valve body 20 between the second cover component 22 and the valve seat 30. The second piston 60 is axially movable in the main valve core 40. The second piston 60 divides the inner space of the valve body 20 in the axial direction. The second piston 60 has circular plates 61 and 62, a leaf spring component 63, a gasket 64, a valve core support component 65, a valve core 66, and a compression coil spring 68. The circular plates 61 and 62, the leaf spring component 63 (circular plate portion 63a, multiple spring plates 63b, through hole 63c), the gasket 64 (bottom wall portion 64a, peripheral wall portion 64b), the valve core support component 65 (circular plate portion 65a, protrusion 65b), the valve core 66 (base end portion 66a, top end portion 66b), and the compression coil spring 68 of the first piston have the same structure as the circular plates 51 and 52, the leaf spring component 53 (circular plate portion 53a, multiple spring plates 53b, through hole 53c), the gasket 54 (bottom wall portion 54a, peripheral wall portion 54b), the valve core support component 55 (circular plate portion 55a, protrusion 55b), the valve core 56 (base end portion 56a, top end portion 56b), and the compression coil spring 58. The valve core 66 opens and closes the second connection port 22a of the second cover component 22.

[0087] The second piston 60 has a second flow passage 67 extending from the second cover member 22 side to the valve seat 30 side. The second flow passage 67 has the smallest passage area in the through hole 63c formed in the leaf spring member 63. The diameter of the through hole 63c is the smallest diameter of the second flow passage 67. The diameter of the through hole 63c is the same as the diameter of the through hole 53c of the first piston 50.

[0088] The connecting body 70 is a metal bracket that connects the first piston 50 and the second piston 60. A valve core fitting hole 71 is formed in the connecting body 70 for the main valve core 40 to engage. The connecting body 70 allows the main valve core 40 to slide on the valve seat surface 30a as the first piston 50 and the second piston 60 move.

[0089] The inner space of the valve body 20 is divided into a first working chamber 11 between the first cover component 21 and the first piston 50, a second working chamber 12 between the second cover component 22 and the second piston 60, and a valve chamber 13 between the first piston 50 and the second piston 60. An inlet port 23 is connected to the valve chamber 13. The valve chamber 13 and the first working chamber 11 are connected via a first flow path 57 of the first piston 50. The valve chamber 13 and the second working chamber 12 are connected via a second flow path 67 of the second piston 60.

[0090] The pilot valve 110 has a valve body 120, a valve seat 130, a pilot valve core 140, a fixed iron core 150 (also referred to as a "suction element"), a plunger 160, and an electromagnetic coil not shown.

[0091] The valve body 120 has a cylindrical shape. One end of the valve body 120 (at...) Figure 1 , Figure 2 The left end of the valve body 120 is closed by the cover component 121. The other end of the valve body 120 (in the middle) is closed by the cover component 121. Figure 1 , Figure 2 The valve body 120 (right end) is enclosed by a fixed iron core 150. An electromagnetic coil (not shown) is disposed on the outside of the valve body 120.

[0092] The valve seat 130 is made of stainless steel or other metal. The valve seat 130 is located inside the valve body 120, in the lower part of the valve body 120 near the cover member 121. The valve seat 130 has an upward-facing seat surface 130a. Figure 5 As shown, the valve seat 130 has a direction from the cover member 121 side to the fixed iron core 150 side (in Figure 5 In the valve, from left to right, the first port 131, the general-purpose port 133, and the second port 132 are arranged in sequence. The first port 131, the general-purpose port 133, and the second port 132 are open on the valve seat surface 130a. The diameters of the first port 131, the general-purpose port 133, and the second port 132 are the same. A first connecting pipe 191 is connected to the first port 131. A general-purpose connecting pipe 193 is connected to the general-purpose port 133. A second connecting pipe 192 is connected to the second port 132.

[0093] The first connecting pipe 191 connects the first port 131 and the first connecting port 21a of the first cover component 21. The general connecting pipe 193 connects the general port 133 and the outlet conduit 93. The second connecting pipe 192 connects the second port 132 and the second connecting port 22a of the second cover component 22.

[0094] The pilot valve core 140 has a cuboid shape. The pilot valve core 140 has a U-shaped bend passage 141 on its inner side. The U-shaped bend passage 141 is separated from the inner space of the valve body 120. The pilot valve core 140 is disposed on the valve seat surface 130a. The pilot valve core 140 slides on the valve seat surface 130a and is positioned at the first pilot valve core position where the U-shaped bend passage 141 connects the first port 131 and the general purpose port 133. Figure 1 The position of the pilot valve core 140 shown) and the position of the second pilot valve core located in the U-shaped bend passage 141 connecting the second port 132 and the general port 133 ( Figure 2 (The position of the pilot valve core 140 is shown). The general purpose port 133 is always connected to the U-turn passage 141.

[0095] The fixed iron core 150 has a cylindrical shape. The fixed iron core 150 is engaged with the other end of the valve body 120.

[0096] The plunger 160 has a cylindrical shape. The plunger 160 is disposed inside the valve body 120. The plunger 160 is axially movable within the valve body 120. The plunger 160 is connected to the pilot valve core 140 via the valve shaft 170. A plunger spring 161 is disposed between the plunger 160 and the fixed iron core 150. The plunger spring 161 is a compression helical spring. The plunger spring 161 presses the plunger 160 towards the cover member 121.

[0097] Next, an example of the operation of the flow path switching valve 1 will be described. The flow path switching valve 1 is connected to the refrigeration cycle of the air conditioner. High-pressure refrigerant flows in the inlet pipe 83, and low-pressure refrigerant flows in the outlet pipe 93.

[0098] When the electromagnetic coil (not shown) of the pilot valve 110 is not energized, the fixed iron core 150 and the plunger 160 are not magnetized, and the plunger 160 is pressed by the plunger spring 161 and moves towards the cover member 121. The pilot valve core 140, connected to the valve shaft 170 via the plunger 160, slides towards the cover member 121 on the valve seat surface 130a and is positioned in the first pilot valve core position. The outlet port 33 and the first working chamber 11 are connected by a first connecting passage C1 formed by the outlet conduit 93, the universal connecting pipe 193, the universal port 133, the U-shaped bend passage 141, the first port 131, the first connecting pipe 191, and the first connecting port 21a. High-pressure refrigerant is introduced into the valve chamber 13 from the inlet port 23. High-pressure refrigerant is discharged from the first working chamber 11 through the first connecting passage C1 to the outlet port 33 for the flow of low-pressure refrigerant. Additionally, high-pressure refrigerant is introduced from valve chamber 13 into first working chamber 11 via first flow path 57. Due to the pressure difference between valve chamber 13 and first working chamber 11, first piston 50 and second piston 60 move towards first cover component 21. Accompanying the movement of first piston 50 and second piston 60, main valve core 40 slides on valve seat surface 30a and is positioned at the first main valve core position. Thus, inlet port 23 and second port 32 are connected via valve chamber 13, and outlet port 33 and first port 31 are connected via U-shaped bend passage 41. First connection port 21a is closed by valve core 56 of first piston 50, and second connection port 22a is open relative to second working chamber 12. After first connection port 21a is closed, valve chamber 13, first working chamber 11, and second working chamber 12 are filled with high-pressure refrigerant.

[0099] When the solenoid coil (not shown) of the pilot valve 110 is energized, the fixed iron core 150 and the plunger 160 are magnetized, and the plunger 160 moves toward the fixed iron core 150. The pilot valve core 140, connected to the valve shaft 170 via the plunger 160, moves toward the fixed iron core 150 on the valve seat surface 130a and is positioned at the second pilot valve core position. The outlet port 33 and the second working chamber 12 are connected via the second connecting passage C2, which consists of the outlet conduit 93, the universal connecting pipe 193, the universal port 133, the U-turn passage 141, the second port 132, the second connecting pipe 192, and the second connecting port 22a. High-pressure refrigerant is introduced into the valve chamber 13 from the inlet port 23. High-pressure refrigerant is discharged from the second working chamber 12 via the second connecting passage C2 to the outlet port 33, which supplies low-pressure refrigerant. Additionally, high-pressure refrigerant is introduced from the valve chamber 13 into the second working chamber 12 via the second flow path 67. Due to the pressure difference between valve chamber 13 and second working chamber 12, first piston 50 and second piston 60 move towards the second cover component 22. Accompanying the movement of first piston 50 and second piston 60, main valve core 40 slides on valve seat surface 30a and is positioned at the second main valve core position. Thus, inlet port 23 and first port 31 are connected via valve chamber 13, and outlet port 33 and second port 32 are connected via U-shaped bend passage 41. First connection port 21a is open to first working chamber 11, and second connection port 22a is closed by valve core 66 of second piston 60. After second connection port 22a is closed, valve chamber 13, first working chamber 11, and second working chamber 12 are filled with high-pressure refrigerant.

[0100] In the above operation, in the flow path switching valve 1, the refrigerant pressure in the first chamber 11 is a value corresponding to the balance between the pressure drop caused by the discharge of high-pressure refrigerant through the first connecting passage C1 and the pressure rise caused by the introduction of high-pressure refrigerant through the first flow path 57. Similarly, the refrigerant pressure in the second chamber 12 is a value corresponding to the balance between the pressure drop caused by the discharge of high-pressure refrigerant through the second connecting passage C2 and the pressure rise caused by the introduction of high-pressure refrigerant through the second flow path 67.

[0101] The first connection passage C1 has the smallest passage area in the general-purpose port 133 of the pilot valve 110. The diameter of the general-purpose port 133 is the minimum diameter Db of the first connection passage C1. The second connection passage C2 also has the smallest passage area in the general-purpose port 133 of the pilot valve 110. The diameter of the general-purpose port 133 is also the minimum diameter of the second connection passage C2.

[0102] The flow path switching valve 1 is configured such that the ratio of the minimum diameter Da of the first flow path 57 to the minimum diameter Db of the first connecting passage C1, Da / Db, satisfies the following formula (1). ΔP is the differential pressure between the valve chamber 13 and the first working chamber 11 when the outlet port 33 and the first working chamber 11 are connected through the first connecting passage C1. Furthermore, the flow path switching valve 1 is used in refrigeration cycles where the differential pressure ΔP is 0.2 MPa or higher, so that the first piston 50 and the second piston 60 can move reliably.

[0103] Rmin≤Da / Db…(1)

[0104] in,

[0105] When 0.2MPa≤ΔP≤10.0MPa,

[0106] Rmin=(ΔP+(21.65)) / 30.27.

[0107] By ensuring that the ratio Da / Db satisfies the above formula (1), the time required for the movement of the first and second pistons during flow path switching (i.e., the time it takes for the main valve core 40 to move from the second main valve position to the first main valve core position (hereinafter referred to as "flow path switching time T1")) can be set to 1.1 seconds or more. If the flow path switching time T1 is 1.1 seconds or more, the noise level during the sliding of the main valve core 40 can be suppressed to below 45 dB.

[0108] Furthermore, preferably, the flow path switching valve 1 is configured such that the ratio Da / Db satisfies the following formula (1A).

[0109] Rmin≤Da / Db≤Rmax…(1A)

[0110] in,

[0111] When 0.2MPa≤ΔP≤10.0MPa,

[0112] Rmin=(ΔP+(21.65)) / 30.27

[0113] When 0.2MPa≤ΔP<1.0MPa,

[0114] Rmax = (ΔP + (11.80)) / 11.43

[0115] When 1.0 MPa ≤ ΔP < 2.0 MPa,

[0116] Rmax = (ΔP + (12.97)) / 12.47

[0117] When 2.0 MPa ≤ ΔP < 3.0 MPa,

[0118] Rmax = (ΔP + (5.62)) / 6.35

[0119] When 3.0 MPa ≤ ΔP < 4.0 MPa,

[0120] Rmax = (ΔP + (2.48)) / 4.04

[0121] When 4.0 MPa ≤ ΔP < 5.0 MPa,

[0122] Rmax = (ΔP + (0.90)) / 3.05

[0123] When 5.0 MPa ≤ ΔP < 6.0 MPa,

[0124] Rmax = (ΔP + (-1.23)) / 1.95

[0125] When 6.0 MPa ≤ ΔP < 7.0 MPa,

[0126] Rmax = (ΔP + (-3.28)) / 1.11

[0127] When 7.0 MPa ≤ ΔP < 8.0 MPa,

[0128] Rmax = (ΔP + (-5.22)) / 0.53

[0129] When 8.0 MPa ≤ ΔP ≤ 10.0 MPa,

[0130] Rmax = (ΔP + (-5.99)) / 0.38

[0131] By making the ratio Da / Db satisfy the above formula (1A), the flow path switching time T1 can be made to be more than 1.1 seconds and less than 60 seconds.

[0132] Alternatively, preferably, the ratio Da / Db of the flow path switching valve 1 satisfies the following formula (1B).

[0133] Rmin≤Da / Db≤Rmax…(1B)

[0134] in,

[0135] When 0.2MPa≤ΔP≤10.0MPa,

[0136] Rmin=(ΔP+(21.65)) / 30.27

[0137] When 0.2MPa≤ΔP<1.0MPa,

[0138] Rmax = (ΔP + (15.80)) / 16.00

[0139] When 1.0MPa≤ΔP<2.0MPa,

[0140] Rmax = (ΔP + (14.41)) / 14.67

[0141] When 2.0 MPa ≤ ΔP < 3.0 MPa,

[0142] Rmax = (ΔP + (6.96)) / 8.01

[0143] When 3.0 MPa ≤ ΔP < 4.0 MPa,

[0144] Rmax = (ΔP + (3.56)) / 5.28

[0145] When 4.0 MPa ≤ ΔP < 5.0 MPa,

[0146] Rmax = (ΔP + (1.85)) / 4.08

[0147] When 5.0 MPa ≤ ΔP < 6.0 MPa,

[0148] Rmax = (ΔP + (-0.48)) / 2.69

[0149] When 6.0 MPa ≤ ΔP < 7.0 MPa,

[0150] Rmax = (ΔP + (-2.73)) / 1.60

[0151] When 7.0 MPa ≤ ΔP < 8.0 MPa,

[0152] Rmax = (ΔP + (-4.83)) / 0.81

[0153] When 8.0 MPa ≤ ΔP ≤ 10.0 MPa,

[0154] Rmax = (ΔP + (-5.50)) / 0.64

[0155] By making the ratio Da / Db satisfy the above formula (1B), the flow path switching time T1 can be made to be more than 1.1 seconds and less than 30 seconds.

[0156] Furthermore, the minimum diameter of the second flow path 67 of the flow path switching valve 1 is the same as the minimum diameter Da of the first flow path 57, and the minimum diameter of the second connecting passage C2 is the same as the minimum diameter Db of the first connecting passage C1. The flow path switching valve 1 is configured such that when the minimum diameter of the second flow path 67 is set to Da, the minimum diameter of the second connecting passage C2 is set to Db, and the differential pressure between the valve chamber 13 and the second working chamber 12 when the outlet port 33 and the second working chamber 12 are connected through the second connecting passage C2 is set to ΔP, the above formula (1) is satisfied. Therefore, the time for the main valve core 40 to move from the first main valve core position to the second main valve core position (hereinafter referred to as "flow path switching time T2") can also be 1.1 seconds or more. If the flow path switching time T2 is 1.1 seconds or more, the noise level when the main valve core 40 slides can be suppressed to below 45 dB.

[0157] The flow path switching valve 1 of this embodiment includes a main valve 10 and a pilot valve 110. The main valve 10 includes: a cylindrical valve body 20 closed at one end and the other end; a valve seat 30 disposed inside the valve body 20; a first piston 50 disposed between a first cover member 21 at one end of the closed valve body 20 and the valve seat 30; a second piston 60 disposed between a second cover member 22 at the other end of the closed valve body 20 and the valve seat 30; and a main valve core 40 disposed on a valve seat surface 30a of the valve seat 30, and sliding axially along the valve body 20 together with the first piston 50 and the second piston 60. The inner space of the valve body 20 is divided into a valve chamber 13 between the first piston 50 and the second piston 60; a first working chamber 11 between the first cover member 21 and the first piston 50; and a second working chamber 12 between the second cover member 22 and the second piston 60. The valve body 20 has an inlet port 23 connected to the valve chamber 13. Valve seat 30 has an outlet port 33 connected to the U-shaped bend passage 41 of main valve core 40. First piston 50 has a first flow passage 57 connecting valve chamber 13 and first working chamber 11. Second piston 60 has a second flow passage 67 connecting valve chamber 13 and second working chamber 12. Pilot valve 110 is configured to switch between the first connection passage C1 connecting outlet port 33 and first working chamber 11 and the second connection passage C2 connecting outlet port 33 and second working chamber 12. Flow path switching valve 1 is configured to satisfy the above formula (1) when the minimum diameter of the first flow passage 57 is set to Da, the minimum diameter of the first connection passage C1 is set to Db, and the differential pressure between valve chamber 13 and first working chamber 11 when outlet port 33 and first working chamber 11 are connected through the first connection passage C1 is set to ΔP.

[0158] The ratio of the minimum diameter Da of the first flow path 57 of the flow path switching valve 1 to the minimum diameter Db of the first connecting passage C1, Da / Db, satisfies the above formula (1). Therefore, the flow path switching time T1 can be made a time that can suppress noise. Thus, the flow path switching valve 1 can suppress noise even without reducing the pressure of the refrigerant introduced into the valve chamber 13.

[0159] Furthermore, the first piston 50 has a leaf spring component 53, which is a metal part. The portion of the first flow path 57 with the minimum diameter Da is formed in the through hole 53c of the leaf spring component 53. The second piston 60 has a leaf spring component 63, which is a metal part. The portion of the second flow path 67 with the minimum diameter is formed in the through hole 63c of the leaf spring component 63. Therefore, compared to the case where the portion of the first flow path 57 with the minimum diameter Da is formed as a synthetic resin part, the machining accuracy of the diameters of the through holes 53c and 63c can be improved. As a result, the accuracy of the Da / Db ratio can be improved, and the flow path switching time T1 can be made a time that can more reliably suppress noise.

[0160] Furthermore, the minimum diameter of the second flow path 67 is the same as the minimum diameter Da of the first flow path 57. The minimum diameter of the second connecting passage C2 is the same as the minimum diameter Db of the first connecting passage C1. The flow path switching valve 1 is configured such that when the minimum diameter of the second flow path 67 is set to Da, the minimum diameter of the second connecting passage C2 is set to Db, and the differential pressure between the valve chamber 13 and the second working chamber 12 when the outlet port 33 is connected to the second working chamber 12 through the second connecting passage C2 is set to ΔP, the above formula (1) is satisfied. As a result, the flow path switching time T2 can be made to a time when noise can be suppressed. Therefore, the flow path switching valve 1 can suppress noise even if the pressure of the refrigerant introduced into the valve chamber 13 is not reduced.

[0161] The inventors of this invention manufactured multiple flow path switching valves 1 with different ratios (Da / Db) between the minimum diameter Da of the first flow path 57 and the minimum diameter Db of the first connecting passage C1. Using these multiple flow path switching valves 1, and connecting the outlet port 33 and the first working chamber 11 via the first connecting passage C1, they measured the change in differential pressure ΔP between the valve chamber 13 and the first working chamber 11, and measured the flow path switching time T1 and the noise level. Through the measurement of the flow path switching time T1 and the noise level, the inventors of this invention determined that when the flow path switching time T1 is 1.1 seconds or more, the noise level can be suppressed to below 45 dB. Furthermore, the noise level "45 dB" is the nighttime reference value for residential areas as specified in the environmental standards for noise levels stipulated in Article 16, Paragraph 1 of the Basic Environmental Law of Japan. In refrigeration cycles, common refrigerants (e.g., R410A) are often used when the differential pressure ΔP is around 1.0 MPa to 1.5 MPa, while carbon dioxide refrigerants are often used when the differential pressure ΔP is around 8 MPa to 10 MPa.

[0162] Furthermore, based on the above measurement results, the inventors of this invention obtained the following graphs: G1_1, which illustrates the combination of the ratio Da / Db and the differential pressure ΔP when the flow path switching time T1 is 1.1 seconds; G30, which illustrates the combination of the ratio Da / Db and the differential pressure ΔP when the flow path switching time is 30 seconds; and G60, which illustrates the combination of the ratio Da / Db and the differential pressure ΔP when the flow path switching time is 60 seconds. Figure 6 These curves G1_1, G30, and G60 are represented. Furthermore, the inventors of this invention derived approximate formulas for these curves G1_1, G30, and G60 to obtain the above formulas (1), (1A), and (1B).

[0163] Figure 7 SA represents the range of combinations of the ratio Da / Db and the differential pressure ΔP that satisfy the above formula (1A). By satisfying the above formula (1A), the flow path switching valve 1 can make the flow path switching time T1 range from 1.1 seconds to 60 seconds, and can achieve noise suppression and short-time flow path switching.

[0164] Figure 8 The range SB represents the combination of the ratio Da / Db and the differential pressure ΔP that satisfies the above formula (1B). By satisfying the above formula (1B), the flow path switching valve 1 can make the flow path switching time T1 1.1 seconds to 30 seconds, and can achieve noise suppression and shorter flow path switching time. For example, in the flow path switching valve 1, when the differential pressure ΔP can be taken in the range of 0.2 MPa to 6.0 MPa, by making the ratio Da / Db 1.0, the flow path switching time T1 can be made 1.1 seconds to 30 seconds.

[0165] In the above embodiments, the main valve core 40 is configured such that when it slides between the first main valve core position and the second main valve core position, the first port 31, the outlet port 33, and the second port 32 are not all connected. Besides this structure, the present invention can also be applied to a structure in which the first port 31, the outlet port 33, and the second port 32 are all connected when the main valve core 40 slides between the first main valve core position and the second main valve core position.

[0166] In addition, in the above embodiments, the terms "first" and "second" are used to distinguish structural components, and the terminology can be interchanged.

[0167] The pilot valve for the flow path switching valve of the present invention is not limited to the structure of the pilot valve 110 described above. Any switching valve that selectively connects one of the first connecting pipe 191 and the second connecting pipe 192 to the universal connecting pipe 193 and closes the other connecting pipe not connected to the universal connecting pipe 193 can replace the pilot valve 110 and be used. "Closed" includes connections to other connecting pipes and conduits in a manner that prevents refrigerant flow. Alternatively, a switching valve that connects one of the first connecting pipe 191 and the second connecting pipe 192 to the first universal connecting pipe connected to the outlet conduit 93 and the other to the second universal connecting pipe connected to the inlet conduit 83 can be used instead of the pilot valve 110.

[0168] While embodiments of the present invention have been described above, the present invention is not limited to these examples. Any additions, deletions, design changes, or appropriate combinations of features of the embodiments made by those skilled in the art without departing from the spirit of the invention are also included within the scope of the present invention.

Claims

1. A flow path switching valve, comprising a main valve and a pilot valve, characterized in that, The main valve has: The valve body is a cylindrical shape with one end closed and the other end closed. A valve seat, which is disposed inside the valve body; A first piston is disposed between one end of the valve body and the valve seat; A second piston is disposed between the other end of the valve body and the valve seat; as well as The main valve core is disposed on the valve seat surface of the valve seat and slides axially along with the first piston and the second piston in the valve body. The inner space of the valve body is divided into a valve chamber between the first piston and the second piston, a first working chamber between one end of the valve body and the first piston, and a second working chamber between the other end of the valve body and the second piston. The valve body has an inlet port that connects to the valve chamber. The valve seat has an outlet port that connects to the U-shaped bend passage of the main valve core. The first piston has a first flow path connecting the valve chamber and the first working chamber. The second piston has a second flow path connecting the valve chamber and the second working chamber. The pilot valve is configured to switch between a first connection path connecting the outlet port and the first working chamber and a second connection path connecting the outlet port and the second working chamber. When the minimum diameter of the first flow path is set to Da, the minimum diameter of the first connection path is set to Db, and the differential pressure between the valve chamber and the first working chamber when the outlet port and the first working chamber are connected through the first connection path is set to ΔP, the flow path switching valve satisfies the following formula (1): Rmin≤Da / Db……(1), in, When 0.2MPa≤ΔP≤10.0MPa, Rmin=(ΔP+(21.65)) / 30.

27.

2. The flow path switching valve according to claim 1, characterized in that, Satisfy the following formula (1A), Rmin≤Da / Db≤Rmax……(1A), in, When 0.2MPa≤ΔP≤10.0MPa, Rmin=(ΔP+(21.65)) / 30.27; When 0.2MPa≤ΔP<1.0MPa, Rmax = (ΔP + (11.80)) / 11.43; When 1.0 MPa ≤ ΔP < 2.0 MPa, Rmax = (ΔP + (12.97)) / 12.47; When 2.0 MPa ≤ ΔP < 3.0 MPa, Rmax = (ΔP + (5.62)) / 6.35; When 3.0 MPa ≤ ΔP < 4.0 MPa, Rmax = (ΔP + (2.48)) / 4.04; When 4.0 MPa ≤ ΔP < 5.0 MPa, Rmax = (ΔP + (0.90)) / 3.05; When 5.0 MPa ≤ ΔP < 6.0 MPa, Rmax = (ΔP + (-1.23)) / 1.95; When 6.0 MPa ≤ ΔP < 7.0 MPa, Rmax = (ΔP + (-3.28)) / 1.11; When 7.0 MPa ≤ ΔP < 8.0 MPa, Rmax = (ΔP + (-5.22)) / 0.53; When 8.0 MPa ≤ ΔP ≤ 10.0 MPa, Rmax = (ΔP + (-5.99)) / 0.

38.

3. The flow path switching valve according to claim 1, characterized in that, Satisfy the following formula (1B), Rmin≤Da / Db≤Rmax......(1B), in, When 0.2MPa≤ΔP≤10.0MPa, Rmin=(ΔP+(21.65)) / 30.27; When 0.2MPa≤ΔP<1.0MPa, Rmax = (ΔP + (15.80)) / 16.00; When 1.0MPa≤ΔP<2.0MPa, Rmax = (ΔP + (14.41)) / 14.67; When 2.0 MPa ≤ ΔP < 3.0 MPa, Rmax = (ΔP + (6.96)) / 8.01; When 3.0 MPa ≤ ΔP < 4.0 MPa, Rmax = (ΔP + (3.56)) / 5.28; When 4.0 MPa ≤ ΔP < 5.0 MPa, Rmax = (ΔP + (1.85)) / 4.08; When 5.0 MPa ≤ ΔP < 6.0 MPa, Rmax = (ΔP + (-0.48)) / 2.69; When 6.0 MPa ≤ ΔP < 7.0 MPa, Rmax = (ΔP + (-2.73)) / 1.60; When 7.0 MPa ≤ ΔP < 8.0 MPa, Rmax = (ΔP + (-4.83)) / 0.81; When 8.0 MPa ≤ ΔP ≤ 10.0 MPa, Rmax = (ΔP + (-5.50)) / 0.

64.

4. The flow path switching valve according to any one of claims 1 to 3, characterized in that, The first piston and the second piston each have metal parts. The portion of the first flow path that has the smallest diameter is the through hole formed in the metal part. The portion of the second flow path that becomes the smallest diameter is the through hole formed in the metal part.

5. The flow path switching valve according to claim 1, characterized in that, The minimum diameter of the second flow path is the same as the minimum diameter Da of the first flow path. The minimum diameter of the second connection path is the same as the minimum diameter Db of the first connection path. When the minimum diameter of the second flow path is set to Da, the minimum diameter of the second connection path is set to Db, and the differential pressure between the valve chamber and the second working chamber when the outlet port is connected to the second working chamber through the second connection path is set to ΔP, the above formula (1) is satisfied.

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