JP7566332B2 - Flow path switching valve and valve device - Google Patents

Description

The present invention relates to a flow path switching valve and a valve device having the same.

Patent Document 1 discloses a three-way switching valve, which is an example of a conventional flow path switching valve. The three-way switching valve connects a selected one of a first inlet pipe and a second inlet pipe to an outlet pipe. The three-way switching valve has a valve body and a valve seat member fixed to the inside of the valve body. The valve body has a first valve chamber above the valve seat member and a second valve chamber below the valve seat member. The first inlet pipe is connected to the first valve chamber. The second inlet pipe is connected to the second valve chamber. The valve seat member has a first connection passage connecting the first valve chamber and the outlet pipe, and a second connection passage connecting the second valve chamber and the outlet pipe.

A first valve body is disposed in the first valve chamber. The first valve body opens and closes a first valve port at the end of the first connecting passage on the side of the first valve chamber. A second valve body is disposed in the second valve chamber. The second valve body opens and closes a second valve port at the end of the second connecting passage on the side of the second valve chamber. The first and second valve bodies are connected by an actuating rod. The first and second valve bodies are linked together.

The first valve body is fixed to the plunger. When an electromagnetic force is applied, the plunger moves upward, and when no electromagnetic force is applied, the plunger moves downward as it is pushed by the first coil spring. The second valve body is fixed to the piston. The piston is pushed upward by the second coil spring.

When an electromagnetic force is acting on the plunger, the first valve body and the second valve body move upward together with the plunger, the first valve body opens the first valve port, and the second valve body closes the second valve port. This connects the first inlet pipe to the outlet pipe via the first valve chamber and the first connecting passage.

When no electromagnetic force is acting on the plunger, the first and second valve bodies move downward together with the plunger, the first valve body closes the first valve port, and the second valve body opens the second valve port. This connects the second inlet pipe to the outlet pipe via the second valve chamber and the second connecting passage.

JP 2011-241846 A

In the above-mentioned three-way switching valve, if the fluid pressure in the second valve chamber (second inlet pipe) is much higher than the fluid pressure in the second valve port (outlet pipe) when the plunger is moving upward, the second valve body receives a large upward force from the fluid. Therefore, even if the first coil spring presses the plunger downward, the plunger cannot move downward, and there is a risk of malfunction in the switching operation of the flow path of the three-way switching valve.

The present invention aims to provide a flow path switching valve and valve device that can suppress problems that occur when there is a large pressure difference between the fluid pressure in the inflow path and the fluid pressure in the outflow path.

In order to achieve the above object, a flow path switching valve according to one aspect of the present invention comprises:
A flow path switching valve that connects a selected one of a first inflow path and a second inflow path to an outflow path,
a valve body having a valve chamber, a first valve port connected to the valve chamber, and a second valve port connected to the valve chamber and disposed opposite the first valve port;
a valve body support member disposed in the valve chamber;
a valve body unit supported by the valve body support member so as to be movable in a direction in which the first valve port and the second valve port face each other, the valve body unit closing the first valve port and opening the second valve port when moved toward the first valve port side, and opening the first valve port and closing the second valve port when moved toward the second valve port side,
The first inlet passage is connected to the first valve port,
The second inlet passage is connected to the second valve port,
The outflow path is connected to the valve chamber,
the valve body unit has a first wall portion having a first valve portion arranged on an outer surface thereof for opening and closing the first valve port, and a second wall portion having a second valve portion arranged on an outer surface thereof for opening and closing the second valve port,
a first back pressure chamber is formed between the valve body support member and an inner surface of the first wall portion,
a second back pressure chamber is formed between the valve body support member and an inner surface of the second wall portion,
the first wall portion has a first pressure equalizing hole that connects the first valve port and the first back pressure chamber when the first valve portion closes the first valve port,
The second wall portion has a second pressure equalizing hole that connects the second valve port and the second back pressure chamber when the second valve portion closes the second valve port.

In the present invention,
The valve body unit has a first valve body, a second valve body, and an actuation rod,
The first valve body has a first wall portion having a disk shape and a first peripheral wall portion having a cylindrical shape connected to an end portion of the first wall portion on the first valve port side,
The second valve body has the second wall portion having a disk shape and a second peripheral wall portion having a cylindrical shape connected to an end portion of the second wall portion on the second valve port side,
The valve body support member has a cylindrical first support portion arranged coaxially inside the first circumferential wall portion, and a cylindrical second support portion arranged coaxially inside the second circumferential wall portion,
The actuating rod is disposed between the first peripheral wall portion and the second peripheral wall portion,
The flow path switching valve,
a valve body driving unit that pushes the first valve body from the first valve port side to the second valve port side;
and a coil spring that presses the second valve body from the second valve port side to the first valve port side.

In the present invention,
a cross-sectional area of the first valve port and a cross-sectional area of the first back pressure chamber are the same,
It is preferable that the cross-sectional area of the second valve port and the cross-sectional area of the second back pressure chamber are the same.

In order to achieve the above object, a valve device according to one aspect of the present invention comprises:
A valve device having a main valve and a pilot valve,
The main valve,
A cylindrical main valve body having one end and the other end closed;
a valve seat disposed inside the main valve body;
A first piston disposed between one end of the main valve body and the valve seat;
A second piston disposed between the other end of the main valve body and the valve seat;
a main valve body that is disposed on a valve seat surface of the valve seat and that slides together with the first piston and the second piston in the axial direction of the main valve body,
an inner space of the main valve body is partitioned into a valve chamber between the first piston and the second piston, a first working chamber between one end of the main valve body and the first piston, and a second working chamber between the other end of the main valve body and the second piston,
the main valve body having an inlet port connected to the valve chamber;
the valve seat has an outlet port connected to the U-turn passage of the main valve body;
the first piston has a first throttle passage connecting the valve chamber and the first working chamber,
the second piston has a second throttle passage connecting the valve chamber and the second working chamber,
The pilot valve is the flow path switching valve,
The first inlet passage is connected to the first working chamber,
The second inlet passage is connected to the second working chamber,
The outlet passage is connected to the outlet port.

According to the present invention, when the first valve section closes the first valve port, the fluid in the first valve port flows into the first back pressure chamber through the first pressure equalizing hole. As a result, the fluid pressure applied to the first wall section from the first valve port side and the fluid pressure applied from the first back pressure chamber side become equal, and the force that the first wall section receives from the fluid can be reduced. Also, when the second valve section closes the second valve port, the fluid in the second valve port flows into the second back pressure chamber through the second pressure equalizing hole. As a result, the fluid pressure applied to the second wall section from the second valve port side and the fluid pressure applied from the second back pressure chamber side become equal, and the force that the second wall section receives from the fluid can be reduced. This makes it possible to suppress malfunctions that occur when the pressure difference between the fluid pressure in the inflow path and the fluid pressure in the outflow path is large.

1 is a cross-sectional view of a valve device according to an embodiment of the present invention. 4 is a cross-sectional view showing another state of the valve device of FIG. 1. FIG. 2 is an enlarged cross-sectional view of a portion of a main valve of the valve device shown in FIG. 1 . 3 is an enlarged cross-sectional view of a portion of the main valve of the valve device shown in FIG. 2. FIG. 2 is a cross-sectional view of a pilot valve of the valve arrangement of FIG. 1 . FIG. 6 is an enlarged cross-sectional view of a portion of the pilot valve of FIG. 5 . FIG. 6 is an enlarged cross-sectional view of another portion of the pilot valve of FIG. 5 . FIG. 6 is a cross-sectional view showing a modified example of the sealing structure of the back pressure chamber of the pilot valve of FIG. 5 . 2A to 2C are diagrams illustrating the operation of the valve device of FIG. 1 (state 1). 4A to 4C are diagrams illustrating the operation of the valve device in FIG. 1 (state 2). 4A to 4C are diagrams illustrating the operation of the valve device in FIG. 1 (state 3). 4 is a diagram illustrating the operation of the valve device of FIG. 1 (state 4). FIG. FIG. 4 is a diagram illustrating the operation of the valve device in FIG. 1 (state 5). FIG. 4 is a diagram illustrating the operation of the valve device in FIG. 1 (state 6). FIG. 7 is a diagram illustrating the operation of the valve device of FIG. 1 (state 7). FIG. 8 is a diagram illustrating the operation of the valve device of FIG. 1 (state 8). FIG. 6 is a cross-sectional view showing a first modified example of the valve body support member of the pilot valve of FIG. 5 . FIG. 7 is a cross-sectional view showing a second modified example of the valve body support member of the pilot valve of FIG. 5 .

Below, a valve device according to one embodiment of the present invention will be described with reference to Figures 1 to 18.

1 and 2 are cross-sectional views of a valve device according to an embodiment of the present invention. FIG. 1 shows a state in which the main valve element of the main valve of the valve device is in the first main valve element position, and FIG. 2 shows a state in which the main valve element is in the second main valve element position. FIG. 3 is an enlarged cross-sectional view of a part (first piston) of the main valve of the valve device shown in FIG. 1. FIG. 4 is an enlarged cross-sectional view of a part (second piston) of the main valve of the valve device shown in FIG. 2. FIG. 5 is a cross-sectional view of the pilot valve of the valve device of FIG. 1. FIGS. 6 and 7 are enlarged cross-sectional views of a part of the pilot valve of FIG. 5. FIG. 6 is an enlarged cross-sectional view of the first valve element of the pilot valve and its vicinity. FIG. 7 is an enlarged cross-sectional view of the second valve element of the pilot valve and its vicinity. FIG. 8 is a cross-sectional view showing a modified example of the sealing structure of the first back pressure chamber of the pilot valve of FIG. 5. FIGS. 9 to 16 are diagrams explaining the operation of the valve device of FIG. 1 (states 1 to 8). FIG. 17 is a cross-sectional view showing a first modified example of the valve element support member of the pilot valve of FIG. 5. Figure 18 is a cross-sectional view showing a second modified example of the valve body support member of the pilot valve in Figure 5. In each figure, the connecting pipes connecting the main valve and the pilot valve are shown typically, with K1-K1, K2-K2, and K3-K3 being connected, respectively. In Figures 5 and 9 to 18, the electromagnetic coil of the pilot valve is omitted. In this specification, descriptions of positions and directions such as up, down, left, and right correspond to the positions and directions in each figure.

As shown in Figures 1 and 2, the valve device 1 of this embodiment has a main valve 10 and a pilot valve 110.

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

The main valve body 20 has a cylindrical shape. The axial direction (axis L direction) of the main valve body 20 coincides with the left-right direction of each figure. The left end (one end) of the main valve body 20 is blocked by a first cover member 21. The right end (the other end) of the main valve body 20 is blocked by a second cover member 22. The first cover member 21 has a first connection port 21a. The second cover member 22 has a second connection port 22a. The main valve body 20 has an inlet port 23. The inlet port 23 is located at the axial center of the upper part of the main valve body 20. An inlet conduit 83 is connected to the inlet port 23.

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

The main valve body 40 has a substantially semi-elliptical spherical shape. The main valve body 40 has a U-turn passage 41 on the inside. The main valve body 40 is disposed on the valve seat surface 30a. The main valve body 40 is slid on the valve seat surface 30a to be positioned at a first main valve body position (the position of the main valve body 40 shown in FIG. 1) where the U-turn passage 41 connects the first switching port 31 and the outlet port 33, and at a second main valve body position (the position of the main valve body 40 shown in FIG. 2) where the U-turn passage 41 connects the second switching port 32 and the outlet port 33. The outlet port 33 is always connected to the U-turn passage 41. The main valve body 40 is made of a synthetic resin such as polyphenylene sulfide (PPS).

The first piston 50 is disposed inside the main valve body 20 between the first cover member 21 and the valve seat 30. The first piston 50 is movable in the axial direction L. The first piston 50 divides the inner space of the main valve body 20 in the axial direction L. As shown in FIG. 3, the first piston 50 has disks 51 and 52, a leaf spring member 53, a packing 54, a valve body support plate 55, a valve body 56, and a compression coil spring 58. The disks 51 and 52 are made of metal such as stainless steel. The outer diameter of the disk 51 is slightly smaller than the inner diameter of the main valve body 20. The outer diameter of the disk 52 is smaller than the outer diameter of the disk 51. The leaf spring member 53 is a metal part. The leaf spring member 53 has a disk portion 53a and a plurality of spring pieces 53b connected to the periphery of the disk portion 53a. The packing 54 is made of a synthetic resin such as polytetrafluoroethylene (PTFE). The packing 54 has a circular tray shape. The packing 54 has a disk-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 arranged inside the packing 54. The disk portion 53a of the leaf spring member 53 and the bottom wall portion 54a of the packing 54 are in contact with each other. The disks 51 and 52 are fastened by bolts (not shown), and the disk portion 53a and the bottom wall portion 54a are held between the disks 51 and 52. The multiple spring pieces 53b of the leaf spring member 53 press the peripheral wall portion 54b of the packing 54 from the inside toward the outside. The peripheral wall portion 54b is in contact with the inner circumferential surface of the main valve body 20. The valve body support plate 55 is made of a metal such as brass. The valve body support plate 55 has a circular flat plate portion 55a and a protrusion 55b. The flat plate portion 55a is joined to the surface of the disk 51 on the side of the first cover member 21. The protrusion 55b is disposed at the center of the flat plate portion 55a. The valve body 56 is made of a synthetic resin such as PPS. The valve body 56 has a cylindrical shape. The valve body 56 is supported by the protrusion 55b of the valve body support plate 55 so as to be movable in the axial direction L. The base end portion 56a of the valve body 56 is disposed inside the protrusion 55b. The tip portion 56b of the valve body 56 protrudes outside the protrusion 55b. The base end portion 56a of the valve body 56 is pressed against the packing 54 by a compression coil spring 58. The tip portion 56b of the valve body 56 is formed in a substantially conical shape. The valve body 56 opens and closes the first connection port 21a of the first lid member 21.

The first piston 50 has a first throttle passage 57 that penetrates from the valve seat 30 side to the first lid member 21 side. The first throttle passage 57 has the smallest passage area at the through hole 53c formed in the leaf spring member 53.

The second piston 60 is disposed inside the main valve body 20, between the second lid member 22 and the valve seat 30. The second piston 60 is movable in the axial direction L. The second piston 60 divides the inner space of the main valve body 20 in the axial direction L. As shown in FIG. 4, the second piston 60 has discs 61, 62, a leaf spring member 63, a gasket 64, a valve body support plate 65, a valve body 66, and a compression coil spring 68. The discs 61, 62, the leaf spring member 63 (disc portion 63a, multiple spring pieces 63b, through hole 63c), the gasket 64 (bottom wall portion 64a, peripheral wall portion 64b), the valve body support plate 65 (flat plate portion 65a, protrusion 65b), the valve body 66 (base end portion 66a, tip end portion 66b), and the compression coil spring 68 have the same configuration as the discs 51, 52, the leaf spring member 53 (disc portion 53a, multiple spring pieces 53b, through hole 53c), the gasket 54 (bottom wall portion 54a, peripheral wall portion 54b), the valve body support plate 55 (flat plate portion 55a, protrusion 55b), the valve body 56 (base end portion 56a, tip end portion 56b), and the compression coil spring 58 of the first piston. The valve body 66 opens and closes the second connection port 22a of the second lid member 22.

The second piston 60 has a second throttle passage 67 that penetrates from the valve seat 30 side to the second lid member 22 side. The second throttle passage 67 has the smallest passage area at the through hole 63c formed in the leaf spring member 63.

The connecting body 70 is a metal bracket that connects the first piston 50 and the second piston 60. The connecting body 70 has a valve body fitting hole 71 into which the main valve body 40 is fitted. The connecting body 70 slides the main valve body 40 on the valve seat surface 30a as the first piston 50 and the second piston 60 move.

The inner space of the main valve body 20 is divided into a first working chamber 11 between the first cover member 21 and the first piston 50, a second working chamber 12 between the second cover member 22 and the second piston 60, and a valve chamber 13 between the first piston 50 and the second piston 60. The valve chamber 13 is divided into a U-turn passage 41. The inlet port 23 is connected to the valve chamber 13. The valve chamber 13 and the first working chamber 11 are connected via the first throttle passage 57 of the first piston 50. The valve chamber 13 and the second working chamber 12 are connected via the second throttle passage 67 of the second piston 60.

As shown in FIG. 5, the pilot valve 110 has a valve body 120, a fixed core 130 (also called an "attractor"), a plunger 140, an electromagnetic coil 150 (see FIG. 1), a first valve seat member 160, a second valve seat member 170, a valve body support member 180, and a valve body unit 200. The pilot valve 110 is a flow path switching valve that connects a selected one of the first connecting pipe 301 and the second connecting pipe 302 to the third connecting pipe 303.

The valve body 120 has a cylindrical shape. The axial direction (axis M direction) of the valve body 120 coincides with the left-right direction of each figure. The fixed core 130 is disposed inside the left end 120a (one end) of the valve body 120. The plunger 140 is disposed inside the valve body 120 so as to be movable in the axis M direction. A first coil spring 145 is disposed between the fixed core 130 and the plunger 140. The first coil spring 145 presses the plunger 140 toward the right end 120b (other end) of the valve body 120. The electromagnetic coil 150 is disposed outside the valve body 120. When the electromagnetic coil 150 is energized, an electromagnetic force acts on the fixed core 130 and the plunger 140, and the plunger 140 moves toward the left end 120a. When the electromagnetic coil 150 is de-energized, no electromagnetic force acts on the fixed core 130 and the plunger 140, and the plunger 140 is pushed by the first coil spring 145 and moves toward the right end 120b.

The first valve seat member 160 has an annular shape. The first valve seat member 160 is disposed inside the valve body 120 at the axial center. The first valve seat member 160 divides the inner space of the valve body 120 in the axial direction. The second valve seat member 170 has a cylindrical shape. The second valve seat member 170 is disposed inside the right end portion 120b of the valve body 120. The first valve seat member 160 and the second valve seat member 170 are arranged side by side with a space (valve chamber 122) in the axial direction M. The inner space of the valve body 120 is divided into a plunger chamber 121 between the fixed iron core 130 and the first valve seat member 160, and a valve chamber 122 between the first valve seat member 160 and the second valve seat member 170.

The first valve seat member 160 has a first valve port 161, which is a circular hole that penetrates from the left surface (the surface on the plunger chamber 121 side) to the right surface (the surface on the valve chamber 122 side). The right surface of the first valve seat member 160 has a circular first valve seat 162 that surrounds the first valve port 161. The inner diameter of the first valve port 161 is larger than the outer diameter of the tip (right end) of the plunger 140. The tip of the plunger 140 is disposed inside the first valve port 161. The left surface (the surface on the valve chamber 122 side) of the second valve seat member 170 has a second valve port 171, which is a circular hole, and a circular second valve seat 172 that surrounds the second valve port 171. The second valve port 171 faces the first valve port 161 in the direction of the axis M. The valve body 120, the first valve seat member 160, and the second valve seat member 170 are made of a metal such as stainless steel.

The valve body support member 180 is disposed in the valve chamber 122. The valve body support member 180 has a first support portion 181, a second support portion 182, a base portion 183, a first cylindrical portion 184, and a second cylindrical portion 185. The first support portion 181, the second support portion 182, and the base portion 183 each have a cylindrical shape. The outer diameter of the first support portion 181 and the outer diameter of the second support portion 182 are the same. The outer diameter of the base portion 183 is larger than the outer diameter of the first support portion 181. The first support portion 181 is coaxially connected to the left surface (surface on the first valve seat member 160 side) of the base portion 183. The second support portion 182 is coaxially connected to the right surface (surface on the second valve seat member 170 side) of the base portion 183. The first support portion 181, the second support portion 182, and the base portion 183 are made of a metal such as stainless steel, and are integrally formed. The base portion 183 has a plurality of support holes 183a formed therein, penetrating from the left surface to the right surface. The outer diameter of the first cylindrical portion 184 and the outer diameter of the second cylindrical portion 185 are the same. The outer diameter of the first cylindrical portion 184 is slightly smaller than the inner diameter of the valve body 120. A part of the base portion 183 is fixed to the right end portion of the first cylindrical portion 184 by press-fitting, welding, or the like. The first support portion 181 is disposed inside the first cylindrical portion 184. Another part of the base portion 183 is fixed to the left end portion of the second cylindrical portion 185 by press-fitting, welding, or the like. The second support portion 182 is disposed inside the second cylindrical portion 185. The base portion 183, the first cylindrical portion 184, and the second cylindrical portion 185 are disposed coaxially. The axial length of the valve body support member 180 is slightly smaller than the length of the valve chamber 122 (the length between the first valve seat member 160 and the second valve seat member 170). The valve body support member 180 is slightly movable in the direction of the axis M.

In the pilot valve 110, the valve body support member 180A shown in FIG. 17 may be disposed in the valve chamber 122 instead of the valve body support member 180. The valve body support member 180A does not include the first cylindrical portion 184 and the second cylindrical portion 185, and a part of the base 183 is hermetically fixed to the right end of one part (left part 120L) of the valve body 120 divided into two by welding or the like, and another part of the base 183 is hermetically fixed to the left end of the other part (right part 120R) by welding or the like. The base 183, the left part 120L, and the right part 120R are disposed coaxially. Alternatively, in the pilot valve 110, the valve body support member 180B shown in FIG. 18 may be disposed in the valve chamber 122 instead of the valve body support member 180. The valve body support member 180B does not include the first cylindrical portion 184 and the second cylindrical portion 185, and the base portion 183 is fixed to the valve body 120 at point S by welding or crimping.

The valve body unit 200 has a first valve body 210, a second valve body 220, and a plurality of actuating rods 230. The first valve body 210, the second valve body 220, and the plurality of actuating rods 230 are made of a metal such as stainless steel.

The first valve body 210 has a cylindrical shape with a closed left end and an open right end. As shown in FIG. 6, the first valve body 210 has a first peripheral wall portion 211 and a first wall portion 212. The first peripheral wall portion 211 has a cylindrical shape. The inner diameter of the first peripheral wall portion 211 is slightly larger than the outer diameter of the first support portion 181 and is the same as the inner diameter of the first valve port 161. The first support portion 181 is coaxially arranged inside the first peripheral wall portion 211. The first wall portion 212 has a disk shape. The first wall portion 212 is connected to the left end portion (the end portion on the first valve port 161 side) of the first peripheral wall portion 211. The first valve portion 214 is arranged on the left surface 212a (outer surface) of the first wall portion 212. The first valve portion 214 is made of synthetic resin. The first valve portion 214 has an annular shape. The first valve portion 214 has a tapered surface 214a that is brought into contact with and separated from the first valve seat 162. The first valve portion 214 opens and closes the first valve port 161. When the first valve port 161 is opened, the first valve port 161 is connected to the valve chamber 122. When the first valve port 161 is closed, the first valve port 161 is separated from the valve chamber 122. The first wall portion 212 has a cylindrical fixed protrusion 212c protruding from the left surface 212a. The fixed protrusion 212c penetrates the first valve portion 214 and the ring member 215. The ring member 215 is made of a metal such as stainless steel. A tip portion 212d of the fixed protrusion 212c is expanded in the radial direction, and the first valve portion 214 and the ring member 215 are held between the left surface 212a and the tip portion 212d. A first pressure equalizing hole 216 is formed in the first wall portion 212, penetrating from the tip 212d of the fixed protrusion 212c to the right surface 212b (inner surface). The first valve body 210 is supported by the first support portion 181 so as to be movable in the direction of the axis M.

The second valve body 220 has a cylindrical shape with a closed right end and an open left end. As shown in FIG. 7, the second valve body 220 has a second peripheral wall portion 221 and a second wall portion 222. The second peripheral wall portion 221 has a cylindrical shape. The inner diameter of the second peripheral wall portion 221 is slightly larger than the outer diameter of the second support portion 182 and is the same as the inner diameter of the second valve port 171. The second support portion 182 is coaxially arranged inside the second peripheral wall portion 221. The second wall portion 222 has a disk shape. The second wall portion 222 is connected to the right end portion (the end portion on the second valve port 171 side) of the second peripheral wall portion 221. The second valve portion 224 is arranged on the right surface 222a (outer surface) of the second wall portion 222. The second valve portion 224 is made of synthetic resin. The second valve portion 224 has an annular shape. The second valve portion 224 has a tapered surface 224a that is brought into contact with and separated from the second valve seat 172. The second valve portion 224 opens and closes the second valve port 171. When the second valve port 171 is opened, the second valve port 171 is connected to the valve chamber 122. When the second valve port 171 is closed, the second valve port 171 is separated from the valve chamber 122. The second wall portion 222 has a cylindrical fixed protrusion 222c protruding from the right surface 222a. The fixed protrusion 222c penetrates the second valve portion 224 and the ring member 225. The ring member 225 is made of a metal such as stainless steel. A tip portion 222d of the fixed protrusion 222c is expanded in the radial direction, and the second valve portion 224 and the ring member 225 are held between the right surface 222a and the tip portion 222d. The second wall portion 222 is formed with a second pressure equalizing hole 226 that penetrates from the tip portion 222d of the fixed protrusion 222c to the left surface 222b (inner surface). The second valve body 220 is supported by the second support portion 182 so as to be movable in the direction of the axis M. The left end portion of the second peripheral wall portion 221 is formed with an annular flange portion 223 that protrudes radially outward. The second coil spring 146 is disposed between the flange portion 223 and the second valve seat member 170. The second coil spring 146 presses the second valve body 220 from the second valve port 171 side to the first valve port 161 side.

The multiple actuating rods 230 are inserted into multiple support holes 183a in the base 183 of the valve body support member 180. The left end of the actuating rod 230 contacts the right end of the first peripheral wall portion 211 of the first valve body 210. The right end of the actuating rod 230 contacts the left end of the second peripheral wall portion 221 of the second valve body 220.

When the first valve body 210 is pushed by the plunger 140 from the first valve port 161 side to the second valve port 171 side, the first valve body 210 pushes the actuation rod 230, and the actuation rod 230 pushes the second valve body 220. As a result, the first valve body 210, the actuation rod 230, and the second valve body 220 all move toward the second valve port 171 side. Also, when the second valve body 220 is pushed by the second coil spring 146 from the second valve port 171 side to the first valve port 161 side, the second valve body 220 pushes the actuation rod 230, and the actuation rod 230 pushes the first valve body 210. As a result, the first valve body 210, the actuation rod 230, and the second valve body 220 all move toward the first valve port 161 side. The fixed core 130, the plunger 140, the first coil spring 145, and the electromagnetic coil 150 constitute a valve body drive unit that pushes the valve body unit 200 from the first valve seat member 160 side to the second valve seat member 170 side.

6, a first back pressure chamber 191 is formed between the first support portion 181 and the first valve body 210 (between the end face 181a and the right face 212b). The first back pressure chamber 191 is partitioned from the valve chamber 122. The first back pressure chamber 191 is connected to the first valve port 161 via the first pressure equalizing hole 216. The cross-sectional area of the first back pressure chamber 191 (cross-sectional area perpendicular to the axis M) is the same as the cross-sectional area of the first valve port 161 (specifically, the area inside the contact point between the first valve portion 214 and the first valve seat 162). A first sealing portion 250 is arranged on the end face 181a of the first support portion 181. The first sealing portion 250 restricts fluid from flowing between the valve chamber 122 and the first back pressure chamber 191 through the gap between the outer circumferential surface of the first support portion 181 and the inner circumferential surface of the first peripheral wall portion 211.

The first sealing portion 250 has a packing 251, a leaf spring member 252, and a ring member 253. The packing 251 is made of a synthetic resin such as PTFE. The packing 251 has a circular tray shape. The packing 251 has a disk-shaped bottom wall portion 251a and a peripheral wall portion 251b connected to the periphery of the bottom wall portion 251a. The leaf spring member 252 is a metal part. The leaf spring member 252 has a disk portion 252a and a plurality of spring pieces 252b connected to the periphery of the disk portion 252a. The leaf spring member 252 is arranged inside the packing 251. The bottom wall portion 251a of the packing 251 and the disk portion 252a of the leaf spring member 252 are in contact with each other. The plurality of spring pieces 252b of the leaf spring member 252 press the peripheral wall portion 251b of the packing 251 from the inside to the outside. The peripheral wall portion 251b is pressed against the inner peripheral surface of the first peripheral wall portion 211. When the first valve body 210 moves in the direction of the axis M, the outer peripheral surface of the peripheral wall portion 251b slides against the inner peripheral surface of the first peripheral wall portion 211. The ring member 253 is made of a metal such as stainless steel. A cylindrical fixing protrusion 181c protrudes from the end face 181a of the first support portion 181. The fixing protrusion 181c penetrates the bottom wall portion 251a of the packing 251, the disk portion 252a of the leaf spring member 252, and the ring member 253. The tip 181d of the fixed protrusion 181c is expanded in the radial direction, and the gasket 251, the leaf spring member 252, and the ring member 253 are held between the end face 181a and the tip 181d.

As shown in FIG. 7, a second back pressure chamber 192 is formed between the second support portion 182 and the second valve body 220 (between the end face 182a and the left face 222b). The second back pressure chamber 192 is partitioned from the valve chamber 122. The second back pressure chamber 192 is connected to the second valve port 171 via the second pressure equalizing hole 226. The cross-sectional area of the second back pressure chamber 192 (cross-sectional area perpendicular to the axis M) is the same as the cross-sectional area of the second valve port 171 (specifically, the area inside the contact point between the second valve portion 224 and the second valve seat 172). A second sealing portion 260 is arranged on the end face 182a of the second support portion 182. The second sealing portion 260 restricts fluid from flowing between the valve chamber 122 and the second back pressure chamber 192 through the gap between the outer circumferential surface of the second support portion 182 and the inner circumferential surface of the second circumferential wall portion 221.

The second sealing portion 260 has a packing 261, a leaf spring member 262, and a ring member 263. The packing 261 (bottom wall portion 261a, peripheral wall portion 261b), the leaf spring member 262 (disk portion 262a, spring piece 262b), and the ring member 263 have the same configuration as the packing 251 (bottom wall portion 251a, peripheral wall portion 251b), the leaf spring member 252 (disk portion 252a, spring piece 252b), and the ring member 253 of the first sealing portion 250. A cylindrical fixing protrusion 182c protrudes from the end surface 182a of the second support portion 182. The fixing protrusion 182c penetrates the bottom wall portion 261a of the packing 261, the disk portion 262a of the leaf spring member 262, and the ring member 263. The tip 182d of the fixed protrusion 182c is expanded in the radial direction, and the gasket 261, the leaf spring member 262, and the ring member 263 are held between the end face 182a and the tip 182d.

8, in the pilot valve 110, the sealing member 270 may be disposed on the first support portion 181 instead of the first sealing portion 250. In this case, an annular groove is formed by an annular step portion 181b formed on the end face 181a of the first support portion 181 and a disk member 255 held between the end face 181a and the tip portion 181d of the fixed protrusion 181c, and the sealing member 270 is disposed in the annular groove. The sealing member 270 has a seal portion 270a and a cap portion 270b. The seal portion 270a is an annular member made of a rubber material or the like. The seal portion 270a is, for example, an O-ring. The cap portion 270b is an annular band-shaped member made of a synthetic resin such as PTFE that is less elastically deformed than the seal portion 270a. The cap portion 270b is placed on the outer periphery of the seal portion 270a. The outer peripheral surface of the cap portion 270b is in contact with the inner peripheral surface of the first peripheral wall portion 211. When the first valve body 210 moves in the direction of the axis M, the outer peripheral surface of the cap portion 270b slides against the inner peripheral surface of the first peripheral wall portion 211. The sealing member 270 may be composed of only the seal portion 270a. Similarly, the sealing member 270 may be disposed on the second support portion 182 instead of the second sealing portion 260.

The first connecting pipe 301 is connected to the plunger chamber 121. The first connecting pipe 301 is connected to the first valve port 161 via the plunger chamber 121. The second connecting pipe 302 is connected to the second valve port 171. The third connecting pipe 303 is connected to the valve chamber 122. The first connecting pipe 301 is the first inflow path. The second connecting pipe 302 is the second inflow path. The third connecting pipe 303 is the outflow path.

The first connection pipe 301 connects the plunger chamber 121 to the first connection port 21a of the first lid member 21. The second connection pipe 302 connects the second valve port 171 to the second connection port 22a of the second lid member 22. The third connection pipe 303 connects the valve chamber 122 to the outlet conduit 93.

The axes of the valve body 120, the first valve seat member 160 (first valve port 161, first valve seat 162), the second valve seat member 170 (second valve port 171, second valve seat 172), the valve body support member 180 (first support portion 181, second support portion 182, base portion 183), the valve body unit 200 (first valve body 210, second valve body 220), the first back pressure chamber 191 and the second back pressure chamber 192 are aligned on the axis M.

Next, an example of the operation of the valve device 1 will be described with reference to Figures 9 to 16. The valve device 1 is incorporated into the refrigeration cycle of an air conditioner, with high-pressure PH fluid (refrigerant) flowing from the inlet conduit 83 to the valve chamber 13, and low-pressure PL fluid flowing to the outlet conduit 93. The high-pressure PH is a pressure higher than the low-pressure PL. The medium pressure PM is a pressure between the high-pressure PH and low-pressure PL.

9 to 16 show the operating states (states 1 to 8) of the valve device 1. (1) State 1 is a state in which the electromagnetic coil 150 of the pilot valve 110 maintains a non-energized state. In state 1, the main valve body 40 is in the first main valve body position. (2) State 2 is a state immediately after the electromagnetic coil 150 is switched from a non-energized state to an energized state. (3) State 3 is a state following state 2 in which the fluid pressure inside the main valve body 20 and the valve body 120 is in the middle of changing. (4) State 4 is a state following state 3 in which the change in the fluid pressure inside the main valve body 20 and the valve body 120 has progressed further. (5) State 5 is a state following state 4 in which the change in the fluid pressure inside the main valve body 20 and the valve body 120 has completed and the main valve body 40 has moved to the second main valve body position. (6) State 6 is the state immediately after the electromagnetic coil 150 is switched from a conducting state to a non-conducting state. (7) State 7 is a state following State 6 in which the fluid pressure inside the main valve body 20 and the valve body 120 is in the middle of changing. (8) State 8 is a state following State 7 in which the change in the fluid pressure inside the main valve body 20 and the valve body 120 has progressed further. Then, following State 8, when the change in the fluid pressure inside the main valve body 20 and the valve body 120 is complete and the main valve element 40 moves to the first main valve element position, the state returns to State 1. States 1 to 8 are continuous in time.

(State 1: Figure 9)
The main valve body 40 is in the first main valve body position. The inlet conduit 83 is connected to the second conduit 92 through the valve chamber 13. The first conduit 91 is connected to the outlet conduit 93 through the U-turn passage 41 of the main valve body 40. The fluid pressure of the first working chamber 11, the fluid pressure of the second working chamber 12, and the fluid pressure of the valve chamber 13 are high pressure PH. The electromagnetic coil 150 of the pilot valve 110 maintains a non-energized state, and no electromagnetic force acts on the plunger 140. The plunger 140 is pushed by the first coil spring 145 to the right end side of the plunger chamber 121. The valve body unit 200 (the first valve body 210, the working rod 230, and the second valve body 220) is pushed by the plunger 140 to the right end side of the valve chamber 122. The first valve portion 214 is separated from the first valve seat 162 to open the first valve port 161, and the second valve portion 224 is in contact with the second valve seat 172 to close the second valve port 171. The first connection port 21a is closed to the first working chamber 11. The first connection port 21a is connected to the outlet conduit 93 (outlet port 33) via the first connection pipe 301, the plunger chamber 121, the first valve port 161, the valve chamber 122, and the third connection pipe 303. The first back pressure chamber 191 is connected to the first valve port 161 via the first pressure equalizing hole 216. The fluid pressure from the first connection port 21a to the outlet conduit 93 and the fluid pressure of the first back pressure chamber 191 are low pressure PL. The second connection port 22a is open to the second working chamber 12. The second connection port 22a is connected to the second valve port 171 via the second connection pipe 302. The second back pressure chamber 192 is connected to the second valve port 171 via a second pressure equalizing hole 226. The fluid pressure from the second connection port 22a to the second valve port 171 and the fluid pressure in the second back pressure chamber 192 are high pressure PH.

In state 1, the first valve port 161, the valve chamber 122, and the first back pressure chamber 191 are connected. Therefore, the fluid pressure (low pressure PL) applied to the entire surface of the first valve body 210 is uniform, and the force that the first valve body 210 (particularly the first wall portion 212) receives from the fluid is small. Also, in state 1, the second valve port 171 and the valve chamber 122 are separated, and the second valve port 171 and the second back pressure chamber 192 are connected. Therefore, the fluid pressure (high pressure PH) applied from the second valve port 171 side to the second wall portion 222 of the second valve body 220 is equal to the fluid pressure (high pressure PH) applied from the second back pressure chamber 192 side, and the cross-sectional area of the second valve port 171 and the cross-sectional area of the second back pressure chamber 192 are the same, so the force that the second valve body 220 (particularly the second wall portion 222) receives from the fluid is small. Therefore, even if there is a large pressure difference between the fluid pressure in the second valve port 171 and the fluid pressure in the valve chamber 122, the force of the first coil spring 145 can keep the valve body unit 200 at the right end side of the valve chamber 122, preventing the valve body unit 200 from moving due to the force it receives from the fluid.

(State 2: FIG. 10)
When the electromagnetic coil 150 is switched from a non-energized state to an energized state, the second main valve element position is selected as the position of the main valve element 40 (i.e., in the pilot valve 110, the second connecting pipe 302 is selected as the pipe connected to the third connecting pipe 303). An electromagnetic force acts on the fixed core 130 and the plunger 140, and the plunger 140 moves to the left end side of the plunger chamber 121. Immediately after switching to the energized state, as in state 1, the valve element unit 200 is at the right end side of the valve chamber 122, the first valve port 161 is open, and the second valve port 171 is closed. The fluid pressures in each section are the same as in state 1.

(State 3: FIG. 11)
A short time after the electromagnetic coil 150 is switched from a non-energized state to an energized state, the valve body unit 200 is pushed by the second coil spring 146 and moves to the left end side of the valve chamber 122. As a result, the first valve portion 214 contacts the first valve seat 162 to close the first valve port 161, and the second valve portion 224 moves away from the second valve seat 172 to open the second valve port 171. At this time, the first connection port 21a is closed to the first working chamber 11, and when the first valve port 161 is closed, the first connection port 21a, the first connection pipe 301, the plunger chamber 121, and the first valve port 161 become a closed space that is temporarily isolated. Therefore, the fluid pressure from the first connection port 21a to the first valve port 161 and the fluid pressure in the first back pressure chamber 191 remain at the low pressure PL. In addition, the second connection port 22a is open to the second working chamber 12, and when the second valve port 171 is opened, the second working chamber 12 is connected to the outlet conduit 93 via the second connection port 22a, the second connecting pipe 302, the second valve port 171, the valve chamber 122, and the third connecting pipe 303. As a result, fluid flows from the second working chamber 12 to the outlet conduit 93, and the fluid pressure from the second working chamber 12 to the third connecting pipe 303 and the fluid pressure in the second back pressure chamber 192 gradually decrease to the medium pressure PM.

(State 4: FIG. 12)
When time passes after the electromagnetic coil 150 is switched from the non-energized state to the energized state, the pressure difference between the fluid pressure (high pressure PH) in the first working chamber 11 and the fluid pressure (medium pressure PM) in the second working chamber 12 becomes large, and the first piston 50 and the second piston 60 start to move toward the right end side of the main valve body 20. The movement of the first piston 50 opens the first connection port 21a to the first working chamber 11, and fluid flows from the first working chamber 11 to the first connection port 21a, the first connection tube 301, the plunger chamber 121, and the first valve port 161, so that the fluid pressure from the first connection port 21a to the first valve port 161 and the fluid pressure in the first back pressure chamber 191 become high pressure PH. When the fluid pressure in the first back pressure chamber 191 becomes high pressure PH, the valve body support member 180 moves slightly toward the right end side of the valve chamber 122.

(State 5: FIG. 13)
Then, when the main valve body 40 moves to the second main valve body position, the second connection port 22a is closed to the second working chamber 12, and the fluid from the second connection port 22a to the third connection pipe 303 flows to the outlet conduit 93, and the fluid pressure from the second connection port 22a to the third connection pipe 303 and the fluid pressure of the second back pressure chamber 192 become low pressure PL. The first connection port 21a is open to the first working chamber 11, and the fluid pressure from the first connection port 21a to the first valve port 161 and the fluid pressure of the first back pressure chamber 191 are high pressure PH. Fluid flows from the valve chamber 13 to the second working chamber 12 through the second throttle passage 67, and the fluid pressure of the second working chamber 12 becomes high pressure PH. The fluid pressure of the first working chamber 11 and the fluid pressure of the valve chamber 13 are high pressure PH. In this way, the movement of the main valve body 40 from the first main valve body position to the second main valve body position is completed. In this state, the inlet conduit 83 is connected to the first conduit 91 via the valve chamber 13. The second conduit 92 is connected to the outlet conduit 93 via the U-turn passage 41 of the main valve body 40.

In state 5, the first valve port 161 and the valve chamber 122 are separated, and the first valve port 161 and the first back pressure chamber 191 are connected. Therefore, the fluid pressure (high pressure PH) applied from the first valve port 161 side to the first wall portion 212 of the first valve body 210 is equal to the fluid pressure (high pressure PH) applied from the first back pressure chamber 191 side, and the cross-sectional area of the first valve port 161 and the cross-sectional area of the first back pressure chamber 191 are the same, so the force that the first valve body 210 (particularly the first wall portion 212) receives from the fluid is small. Also, in state 5, the second valve port 171, the valve chamber 122, and the second back pressure chamber 192 are connected. Therefore, the fluid pressure (low pressure PL) applied to the entire surface of the second valve body 220 is uniform, and the force that the second valve body 220 (particularly the second wall portion 222) receives from the fluid is small. Therefore, even if there is a large pressure difference between the fluid pressure in the first valve port 161 and the fluid pressure in the valve chamber 122, the force of the second coil spring 146 can keep the valve body unit 200 at the left end side of the valve chamber 122, preventing the valve body unit 200 from moving due to the force it receives from the fluid.

(State 6: FIG. 14)
When the electromagnetic coil 150 is switched from a conducting state to a non-conducting state, the first main valve body position is selected as the position of the main valve body 40 (i.e., in the pilot valve 110, the first connecting pipe 301 is selected as the pipe connected to the third connecting pipe 303). The electromagnetic force acting on the fixed core 130 and the plunger 140 disappears, and the plunger 140 is pushed by the first coil spring 145 and moves to the right end side of the plunger chamber 121, and the plunger 140 comes into contact with the first valve body 210 (ring member 215). Immediately after switching to the non-conducting state, as in state 5, the valve body unit 200 is at the left end side of the valve chamber 122, the first valve port 161 is closed, and the second valve port 171 is open. The fluid pressures of the various parts are the same as in state 5.

(State 7: FIG. 15)
A short time after the electromagnetic coil 150 is switched from the energized state to the de-energized state, the valve body unit 200 is pushed by the plunger 140 and moves to the right end side of the valve chamber 122. As a result, the first valve portion 214 moves away from the first valve seat 162 to open the first valve port 161, and the second valve portion 224 moves into contact with the second valve seat 172 to close the second valve port 171. At this time, the second connection port 22a is closed to the second working chamber 12, and when the second valve port 171 is closed, the second connection port 22a, the second connection pipe 302, and the second valve port 171 become a temporarily isolated closed space. Therefore, the fluid pressure from the second connection port 22a to the second valve port 171 and the fluid pressure in the second back pressure chamber 192 remain at the low pressure PL. In addition, the first connection port 21a is open to the first working chamber 11, and when the first valve port 161 is opened, the first working chamber 11 is connected to the outlet conduit 93 via the first connection port 21a, the first connecting pipe 301, the plunger chamber 121, the first valve port 161, the valve chamber 122, and the third connecting pipe 303. As a result, fluid flows from the first working chamber 11 to the outlet conduit 93, and the fluid pressure from the first working chamber 11 to the third connecting pipe 303 and the fluid pressure in the first back pressure chamber 191 gradually decrease to the medium pressure PM.

(State 8: FIG. 16)
When time passes after the electromagnetic coil 150 is switched from the energized state to the de-energized state, the pressure difference between the fluid pressure (medium pressure PM) in the first working chamber 11 and the fluid pressure (high pressure PH) in the second working chamber 12 becomes large, and the first piston 50 and the second piston 60 start to move toward the left end side of the main valve body 20. The movement of the first piston 50 opens the second connection port 22a to the second working chamber 12, and fluid flows from the second working chamber 12 to the second connection port 22a, the second connection tube 302, and the second valve port 171, so that the fluid pressure from the second connection port 22a to the second valve port 171 and the fluid pressure in the second back pressure chamber 192 become high pressure PH. When the fluid pressure in the second back pressure chamber 192 becomes high pressure PH, the valve body support member 180 moves slightly toward the left end side of the valve chamber 122.

When the main valve body 40 moves to the first main valve body position, the first connection port 21a closes to the first working chamber 11, and the fluid from the first connection port 21a to the third connection pipe 303 flows to the outlet conduit 93, and the fluid pressure from the first connection port 21a to the third connection pipe 303 and the fluid pressure of the first back pressure chamber 191 become low pressure PL. The second connection port 22a opens to the second working chamber 12, and the fluid pressure from the second connection port 22a to the second valve port 171 and the fluid pressure of the second back pressure chamber 192 are high pressure PH. Fluid flows from the valve chamber 13 to the first working chamber 11 through the first throttle passage 57, and the fluid pressure of the first working chamber 11 becomes high pressure PH. The fluid pressure of the second working chamber 12 and the fluid pressure of the valve chamber 13 are high pressure PH. In this way, the movement of the main valve body 40 from the second main valve body position to the first main valve body position is completed, and the state returns to state 1.

The valve device 1 according to this embodiment has a main valve 10 and a pilot valve 110. The main valve 10 has a cylindrical main valve body 20 with the left and right ends closed, a valve seat 30 arranged inside the main valve body 20, a first piston 50 arranged between the left end of the main valve body 20 and the valve seat 30, a second piston 60 arranged between the right end of the main valve body 20 and the valve seat 30, and a main valve body 40 arranged on the valve seat surface 30a of the valve seat 30 and slid in the axial direction of the main valve body 20 together with the first piston 50 and the second piston 60. The inner space of the main 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 left end of the main valve body 20 and the first piston 50, and a second working chamber 12 between the right end of the main valve body 20 and the second piston 60. The main valve body 20 has an inlet port 23 connected to the valve chamber 13. The valve seat 30 has an outlet port 33 connected to the U-turn passage 41 of the main valve body 40. The first piston 50 has a first throttle passage 57 that connects the valve chamber 13 and the first working chamber 11. The second piston 60 has a second throttle passage 67 that connects the valve chamber 13 and the second working chamber 12.

The pilot valve 110 has a valve body 120 having a valve chamber 122, a first valve port 161 connected to the valve chamber 122, and a second valve port 171 connected to the valve chamber 122 and arranged opposite the first valve port 161, a valve body support member 180 arranged in the valve chamber 122, and a valve body unit 200 that is supported on the valve body support member 180 so as to be movable in the direction in which the first valve port 161 and the second valve port 171 face each other (axis M direction), and that closes the first valve port 161 and opens the second valve port 171 when it moves toward the first valve port 161, and opens the first valve port 161 and closes the second valve port 171 when it moves toward the second valve port 171. A first connecting pipe 301 is connected to the first valve port 161. A second connecting pipe 302 is connected to the second valve port 171. A third connecting pipe 303 is connected to the valve chamber 122. The valve body unit 200 has a first wall portion 212 having a first valve portion 214 arranged on a left surface 212a for opening and closing the first valve port 161, and a second wall portion 222 having a second valve portion 224 arranged on a right surface 222a for opening and closing the second valve port 171. A first back pressure chamber 191 is formed between the valve body support member 180 and a right surface 212b of the first wall portion 212. A second back pressure chamber 192 is formed between the valve body support member 180 and a left surface 222b of the second wall portion 222. The first wall portion 212 has a first pressure equalizing hole 216 that connects the first valve port 161 and the first back pressure chamber 191 when the first valve portion 214 closes the first valve port 161. The second wall portion 222 has a second pressure equalizing hole 226 that connects the second valve port 171 and the second back pressure chamber 192 when the second valve portion 224 closes the second valve port 171. The first connection pipe 301 is connected to the first working chamber 11 through the first connection port 21a that is opened and closed by the first piston 50 (valve body 56). The second connection pipe 302 is connected to the second working chamber 12 through the second connection port 22a that is opened and closed by the second piston 60 (valve body 66). The third connection pipe 303 is connected to the outlet conduit 93 (outlet port 33).

In the pilot valve 110, when the first valve portion 214 closes the first valve port 161, the fluid in the first valve port 161 flows into the first back pressure chamber 191 through the first pressure equalizing hole 216. As a result, the fluid pressure applied to the first wall portion 212 from the first valve port 161 side and the fluid pressure applied from the first back pressure chamber 191 side become equal, and since the cross-sectional area of the first valve port 161 and the cross-sectional area of the first back pressure chamber 191 are the same, the force that the first wall portion 212 receives from the fluid can be reduced. In addition, when the second valve portion 224 closes the second valve port 171, the fluid in the second valve port 171 flows into the second back pressure chamber 192 through the second pressure equalizing hole 226. As a result, the fluid pressure applied to the second wall portion 222 from the second valve port 171 side and the fluid pressure applied from the second back pressure chamber 192 side become equal, and since the cross-sectional area of the second valve port 171 and the cross-sectional area of the second back pressure chamber 192 are the same, the force that the second wall portion 222 receives from the fluid can be reduced. As a result, the pilot valve 110 can suppress malfunctions that occur when the pressure difference between the fluid pressure of the first connecting tube 301 or the fluid pressure of the second connecting tube 302 and the fluid pressure of the third connecting tube 303 is large.

The valve body unit 200 has a first valve body 210, a second valve body 220, and a plurality of actuating rods 230. The first valve body 210 has a disk-shaped first wall portion 212 and a cylindrical first peripheral wall portion 211 in which the first wall portion 212 is connected to the end portion on the first valve port 161 side. The second valve body 220 has a disk-shaped second wall portion 222 and a cylindrical second peripheral wall portion 221 in which the second wall portion 222 is connected to the end portion on the second valve port 171 side. The valve body support member 180 has a cylindrical first support portion 181 that is coaxially arranged inside the first peripheral wall portion 211, and a cylindrical second support portion 182 that is coaxially arranged inside the second peripheral wall portion 221. The actuating rod 230 is arranged between the first peripheral wall portion 211 and the second peripheral wall portion 221. The pilot valve 110 has a valve body drive unit (plunger 140 and first coil spring 145) that pushes the first valve body 210 from the first valve port 161 side to the second valve port 171 side, and a second coil spring 146 that pushes the second valve body 220 from the second valve port 171 side to the first valve port 161 side. In this way, the valve body unit 200 can be moved in a direction in which the first valve port 161 and the second valve port 171 face each other with a relatively simple configuration.

The cross-sectional area of the first valve port 161 is the same as the cross-sectional area of the first back pressure chamber 191. The cross-sectional area of the second valve port 171 is the same as the cross-sectional area of the second back pressure chamber 192. This makes it possible to further reduce the force that the first wall portion 212 receives from the fluid. Also, it makes it possible to further reduce the force that the second wall portion 222 receives from the fluid. Therefore, the pilot valve 110 can more effectively suppress malfunctions that occur when the pressure difference between the fluid pressure of the first connecting pipe 301 or the fluid pressure of the second connecting pipe 302 and the fluid pressure of the third connecting pipe 303 is large.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configuration of the embodiments. Those embodiments in which a person skilled in the art appropriately adds or removes components or modifies the design, or those in which the features of the embodiments are appropriately combined, are also included in the scope of the present invention as long as they do not go against the spirit of the present invention.

Reference Signs List 1... valve device, 10... main valve, 11... first working chamber, 12... second working chamber, 13... valve chamber, 20... main valve body, 21... first cover member, 21a... first connection port, 22... second cover member, 22a... second connection port, 23... inlet port, 30... valve seat, 30a... valve seat surface, 31... first switching port, 32... second switching port, 33... outlet port, 40... main valve body, 41... U-turn passage, 50...first piston, 51, 52...disk, 53...leaf spring member, 53a...disk portion, 53b...spring piece, 53c...through hole, 54...packing, 54a...bottom wall portion, 54b...circumferential wall portion, 55...valve body support plate, 55a...flat plate portion, 55b...projection portion, 56...valve body, 56a...base end portion, 56b...tip portion, 57...first throttle passage, 58...compression coil spring, 60...second piston, 61, 62...disk, 63...leaf spring member, 63a...disk portion, 63b...spring piece, 63c...through hole, 64...packing, 64a...bottom wall portion, 64b...circumferential wall portion, 65...valve body support plate, 65a...flat plate portion, 65b...projection portion, 66...valve body, 66a...base end portion, 66b...tip portion, 67...second throttle passage, 68...compression coil spring, 70...connecting body, Reference Signs List 71: valve body fitting hole, 83: inlet conduit, 91: first conduit, 92: second conduit, 93: outlet conduit, 110: pilot valve, 120: valve body, 121: plunger chamber, 122: valve chamber, 130: fixed core, 140: plunger, 145: first coil spring, 146: second coil spring, 150: electromagnetic coil, 160: first valve seat member, 161: first valve port, 162...first valve seat, 170...second valve seat member, 171...second valve port, 172...second valve seat, 180...valve body support member, 181...first support portion, 181a...end surface, 181c...fixed protrusion, 181d...tip portion, 182...second support portion, 182a...end surface, 182c...fixed protrusion, 182d...tip portion, 182a...end surface, 183...base portion, 183a...support hole, 184 ...first cylindrical portion, 185...second cylindrical portion, 191...first back pressure chamber, 192...second back pressure chamber, 200...valve body unit, 210...first valve body, 211...first peripheral wall portion, 212...first wall portion, 212a...left surface, 212b...right surface, 212c...fixed protrusion, 212d...tip portion, 214...first valve portion, 214a...tapered surface, 215...ring member, 216...first pressure equalizing hole , 220... second valve body, 221... second peripheral wall portion, 222... second wall portion, 222a... right surface, 222b... left surface, 222c... fixed protrusion, 222d... tip portion, 223... flange portion, 224... second valve portion, 224a... tapered surface, 225... ring member, 226... second pressure equalizing hole, 230... actuation rod, 250... first sealing portion, 251... packing, 251a... bottom wall portion, 251b...peripheral wall portion, 252...leaf spring member, 252a...disk portion, 252b...spring piece, 253...ring member, 260...second sealing portion, 261...packing, 261a...bottom wall portion, 261b...peripheral wall portion, 262...leaf spring member, 262a...disk portion, 262b...spring piece, 263...ring member, 301...first connecting pipe, 302...second connecting pipe, 303...third connecting pipe

Claims (4)

A flow path switching valve that connects a selected one of a first inflow path and a second inflow path to an outflow path,
a valve body having a valve chamber, a first valve port connected to the valve chamber, and a second valve port connected to the valve chamber and disposed opposite the first valve port;
a valve body support member disposed in the valve chamber;
a valve body unit supported by the valve body support member so as to be movable in a direction in which the first valve port and the second valve port face each other, the valve body unit closing the first valve port and opening the second valve port when moved toward the first valve port side, and opening the first valve port and closing the second valve port when moved toward the second valve port side,
The first inlet passage is connected to the first valve port,
The second inlet passage is connected to the second valve port,
The outflow path is connected to the valve chamber,
the valve body unit has a first wall portion having a first valve portion arranged on an outer surface thereof for opening and closing the first valve port, and a second wall portion having a second valve portion arranged on an outer surface thereof for opening and closing the second valve port,
a first back pressure chamber is formed between the valve body support member and an inner surface of the first wall portion,
a second back pressure chamber is formed between the valve body support member and an inner surface of the second wall portion,
the first wall portion has a first pressure equalizing hole that connects the first valve port and the first back pressure chamber when the first valve portion closes the first valve port,
the second wall portion has a second pressure equalizing hole that connects the second valve port and the second back pressure chamber when the second valve portion closes the second valve port. The valve body unit has a first valve body, a second valve body, and an actuation rod,
The first valve body has a first wall portion having a disk shape and a first peripheral wall portion having a cylindrical shape connected to an end portion of the first wall portion on the first valve port side,
The second valve body has the second wall portion having a disk shape and a second peripheral wall portion having a cylindrical shape connected to an end portion of the second wall portion on the second valve port side,
The valve body support member has a cylindrical first support portion arranged coaxially inside the first circumferential wall portion, and a cylindrical second support portion arranged coaxially inside the second circumferential wall portion,
The actuating rod is disposed between the first peripheral wall portion and the second peripheral wall portion,
The flow path switching valve,
a valve body driving unit that pushes the first valve body from the first valve port side to the second valve port side;
2. The flow path switching valve according to claim 1, further comprising: a coil spring that presses the second valve body from the second valve port side to the first valve port side. a cross-sectional area of the first valve port and a cross-sectional area of the first back pressure chamber are the same,
3. The flow path switching valve according to claim 1, wherein a cross-sectional area of the second valve port is the same as a cross-sectional area of the second back pressure chamber. A valve device having a main valve and a pilot valve,
The main valve,
A cylindrical main valve body having one end and the other end closed;
a valve seat disposed inside the main valve body;
A first piston disposed between one end of the main valve body and the valve seat;
A second piston disposed between the other end of the main valve body and the valve seat;
a main valve body that is disposed on a valve seat surface of the valve seat and that slides together with the first piston and the second piston in the axial direction of the main valve body,
an inner space of the main valve body is partitioned into a valve chamber between the first piston and the second piston, a first working chamber between one end of the main valve body and the first piston, and a second working chamber between the other end of the main valve body and the second piston,
the main valve body having an inlet port connected to the valve chamber;
the valve seat has an outlet port connected to the U-turn passage of the main valve body;
the first piston has a first throttle passage connecting the valve chamber and the first working chamber,
the second piston has a second throttle passage connecting the valve chamber and the second working chamber,
The pilot valve is a flow path switching valve according to any one of claims 1 to 3,
The first inlet passage is connected to the first working chamber,
The second inlet passage is connected to the second working chamber,
The outlet passage is connected to the outlet port.

Images