JP7418813B2 - Flow switching valves and flow switching systems - Google Patents

Description

The present invention relates to a flow path switching valve that switches a flow path using fluid pressure, and a flow path switching system having the flow path switching valve.

An example of a conventional flow path switching valve is disclosed in Patent Document 1. The flow path switching valve disclosed in Patent Document 1 includes an actuator that utilizes a pressure difference between high pressure fluid and low pressure fluid flowing within the main valve. This actuator has an operating chamber and a motion conversion mechanism housed in the operating chamber. The motion conversion mechanism includes a bottomed cylindrical pressure-receiving moving body and a rotary drive body disposed inside the pressure-receiving moving body. The pressure receiving moving body moves in the axial direction according to the fluid pressure within the working chamber. The rotary drive body is rotated around the axis as the pressure receiving moving body moves in the axial direction. The flow path switching valve is configured to rotate the main valve body using rotation of the rotary drive body.

Japanese Patent Application Publication No. 2016-89902

In the flow path switching valve disclosed in Patent Document 1, a pressure-receiving moving body moves between two stop positions depending on the fluid pressure within the working chamber. Therefore, the main valve body also moves between two rotational positions. Thereby, there are two flow path connection patterns of the flow path switching valve. Therefore, a flow path switching valve that can provide more flow path connection patterns has been desired.

Therefore, an object of the present invention is to provide a flow path switching valve and a flow path switching system that can provide three flow path connection patterns using fluid pressure.

In order to achieve the above object, a flow path switching valve according to one aspect of the present invention includes a cylindrical main body case with one end closed, and a valve seat arranged so as to close the other end of the main body case. , a rotary valve body that switches connections between a plurality of ports provided on the valve seat; a base piston that is arranged to be axially movable inside the main body case; and a base piston that is axially movable inside the main body case. and a drive piston having a smaller diameter than the base piston, the drive piston being disposed on the other end side of the base piston, and power transmission for rotating the rotary valve body in response to movement of the drive piston in the axial direction. A flow path switching valve having a mechanism, wherein the main body case includes a first piston chamber partitioned by the base piston and the driving piston and arranged in order from the one end side toward the other end side; It has a second piston chamber and a third piston chamber, and the base piston is movable between a first base position and a second base position located on the other end side from the first base position. The driving piston has a first stop position in contact with the base piston in the first base position, a second stop position in contact with the base piston in the second base position, and a second stop position. the base piston and the driving piston are movable between a third stop position located closer to the other end, and the base piston and the driving piston are movable between It is characterized in that it is moved in the axial direction in response to pressure.

In the present invention, a surface of the rotary valve body in contact with the valve seat is formed in an arc shape or a fan shape in a plan view, and the plurality of ports are connected to the surface of the rotary valve body in contact with the valve seat. It is preferable that a fluid passageway, which is a concave portion having an arcuate shape in a plan view, and a sealing portion connected to an end of the fluid passageway and closing the port when passing through the port are preferably provided.

In order to achieve the above object, a flow path switching system according to another aspect of the present invention includes the above flow path switching valve, a base piston control valve, and a driving piston control valve. The base piston control valve has a first base position connection state connecting the first piston chamber and a low-pressure port of the plurality of ports through which low-pressure fluid flows; The drive piston control valve switches between a second base position connection state in which the high pressure port through which high pressure fluid flows among the plurality of ports is connected, and the driving piston control valve connects the second piston chamber and the low pressure port. and a connected state for a contact position that connects the third piston chamber and the high pressure port, and a separated position that connects the second piston chamber and the high pressure port and connects the third piston chamber and the low pressure port. The feature is that the connection state can be switched between.

In the flow path switching valve according to the present invention, the base piston is movable between the first base position and the second base position located on the other end side of the main body case from the first base position. The drive piston has a first stop position where it contacts the base piston at the first base position, a second stop position where it contacts the base piston at the second base position, and a drive piston that is on the other end side of the main body case from the second stop position. It is movable between a third stop position and a third stop position. The base piston and the driving piston are moved in the axial direction of the main body case according to fluid pressure in the first piston chamber, the second piston chamber, and the third piston chamber. Since this is done, by switching the fluid pressures of the first piston chamber, the second piston chamber, and the third piston chamber, the base piston is positioned at the first base position and the second base position, and the driving piston is It is positioned at a first stop position and a second stop position in contact with the base piston, and a third stop position away from the base piston. Therefore, the rotary valve body is rotated according to the movement of the driving piston in the axial direction, and is positioned at three rotational positions corresponding to the first stop position, the second stop position, and the third stop position. Therefore, three flow path connection patterns can be provided using fluid pressure.

FIG. 1 is a diagram showing a flow path switching system according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the flow path switching valve included in the flow path switching system of FIG. 1 (with the driving piston in the first stop position). FIG. 2 is a cross-sectional view of the flow path switching valve included in the flow path switching system of FIG. 1 (with the driving piston in the second stop position). FIG. 2 is a sectional view of the flow path switching valve included in the flow path switching system of FIG. 1 (with the driving piston in the third stop position). FIG. 3 is a cross-sectional view showing how a valve body of a flow path switching valve switches connections between a plurality of ports.

A flow path switching system according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a diagram showing a flow path switching system according to an embodiment of the present invention. FIG. 1 shows a flow path switching valve, a base piston control valve, and a driving piston control valve in cross-sectional view. In FIG. 1, the connection relationship between the flow path switching valve, the base piston control valve, and the driving piston control valve is schematically shown by a two-dot chain line. 2 to 4 are cross-sectional views of the flow path switching valve included in the flow path switching system of FIG. 1. 2 to 4 show states in which the driving piston is at the first stop position, the second stop position, and the third stop position. FIG. 5 is a cross-sectional view showing how the valve body of the flow path switching valve switches connections between a plurality of ports. FIG. 5(a) shows how the ports are connected when the driving piston is at the first stop position. FIG. 5(b) shows how the ports are connected when the driving piston is at a position between the first stop position and the second stop position. FIG. 5(c) shows how the ports are connected when the driving piston is at the second stop position. FIG. 5(d) shows how the ports are connected when the driving piston is at a position between the second stop position and the third stop position. FIG. 5(e) shows how the ports are connected when the driving piston is at the third stop position. In FIGS. 1 to 4, broken lines indicate high-pressure conduits on the near side of the paper. In FIG. 1, two-dot chain lines indicate thin tubes S1 to S3 and T1 to T4.

The flow path switching system of this embodiment is used, for example, in a heat pump air conditioning system to switch the flow path of a refrigerant as a fluid.

As shown in FIG. 1, the flow path switching system 1 includes a flow path switching valve 5, a base piston control valve 80, and a driving piston control valve 90.

The flow path switching valve 5 includes a main body case 10, a valve seat 30, a rotary valve body 40, a base piston 50, a driving piston 60, and a power transmission mechanism 70.

The main body case 10 is formed into a substantially cylindrical shape. The main body case 10 has a base piston accommodating part 11, a driving piston accommodating part 12, and a valve body accommodating part 13, which are arranged in order from one end 10a side to the other end 10b side. The base piston accommodating part 11, the driving piston accommodating part 12, and the valve body accommodating part 13 are continuous in the axis L direction. One end 10a of the main body case 10 is closed by a disk-shaped wall portion 14. The other end 10b of the main body case 10 is closed by a disk-shaped wall portion 15.

The inner diameter of the base piston accommodating portion 11 is larger than the inner diameter of the driving piston accommodating portion 12. A stopper surface 16 is provided on the inside of the main body case 10, which is an annular flat surface facing toward the one end 10a. The stopper surface 16 is arranged between the base piston accommodating portion 11 and the driving piston accommodating portion 12. An annular plate-shaped partition wall 17 is provided inside the main body case 10. The partition wall 17 is arranged to partition the drive piston housing section 12 and the valve body housing section 13 . A cylindrical bearing 18 is disposed inside the drive piston accommodating portion 12 . The bearing 18 is connected to the inner edge of the partition wall 17 . The bearing 18 is formed so that the outer periphery of the cross-sectional shape in the direction orthogonal to the axis L is polygonal (for example, regular hexagonal), and the inner periphery is circular. The end surface of the bearing 18 on the one end 10a side becomes a stopper surface 19.

A base piston 50 is disposed inside the base piston accommodating portion 11 so as to be movable in the direction of the axis L. A driving piston 60 is disposed inside the driving piston accommodating portion 12 so as to be movable in the axis L direction. The main body case 10 has a first piston chamber 21, a second piston chamber 22, and a third piston chamber 23, which are partitioned by a base piston 50 and a driving piston 60. The first piston chamber 21, the second piston chamber 22, and the third piston chamber 23 are arranged in order from one end 10a side to the other end 10b side. Further, the third piston chamber 23 and the valve chamber 24 inside the valve body accommodating portion 13 are partitioned by a partition wall 17 .

The valve seat 30 is formed into a disk shape. The outer diameter of the valve seat 30 is the same as the inner diameter of the valve body accommodating portion 13. The valve seat 30 is arranged inside the main body case 10 so as to close the other end 10b.

The valve seat 30 has a high pressure port pA, a first input/output port pB1, a second input/output port pB2, and a low pressure port pC. The first input/output port pB1, the second input/output port pB2, and the low pressure port pC are formed into circular shapes of the same size. The first input/output port pB1, the second input/output port pB2, and the low pressure port pC are arranged at 90-degree intervals on the same circle E1 (shown in FIG. 5(a)), with their centers being the same. The high pressure port pA is formed in a circular shape smaller than the first input/output port pB1. The center of the high pressure port pA is located on the circle E2 (shown in FIG. 5(a)). The circle E2 has a smaller diameter than the circle E1 in which the center of the first input/output port pB1 is arranged, and is concentric with the circle E1. The center of the high pressure port pA is located at a position shifted by 90 degrees from the center of the first input/output port pB1 and the center of the low pressure port pC. The axis L passes through the centers of the circles E1 and E2.

The high pressure port pA is connected to a discharge port of a compressor (not shown) through a high pressure conduit A. The first input/output port pB1 is connected to a first heat exchanger (not shown) through the first input/output conduit B1. The second input/output port pB2 is connected to a second heat exchanger (not shown) through a second input/output conduit B2. The low pressure port pC is connected through a low pressure conduit C to an inlet of a compressor (not shown).

The rotary valve body 40 is formed into a substantially cylindrical shape. The rotary valve body 40 is arranged in the valve chamber 24. The rotary valve body 40 is rotatable around the axis L. The rotary valve body 40 has a sliding surface 41. The sliding surface 41 is a surface in contact with the valve seat surface 31 of the valve seat 30. The sliding surface 41 is formed in an arc shape (substantially C-shape) in plan view along the circle E1. The sliding surface 41 is provided with a fluid passage 42, a first seal portion 43, and a second seal portion 44. The sliding surface 41 may have a fan shape in plan view. The rotary valve body 40 switches connections between a plurality of ports provided on the valve seat 30 by rotating around the axis L.

The fluid passage 42 is a concave portion having an arcuate shape in plan view along the circle E1. The fluid passage 42 is separated from the valve chamber 24. The fluid passage 42 is formed to be able to connect the first input/output port pB1, the second input/output port pB2, and the low pressure port pC. Depending on the rotational position of the rotary valve body 40, the fluid passage 42 connects the first input/output port pB1, the second input/output port pB2, and the low pressure port pC as shown in FIG. ). Alternatively, the fluid passage 42 connects the second input/output port pB2 and the low pressure port pC as shown in FIG. 5(c) (second rotational position RP2). Alternatively, the fluid passage 42 connects the first input/output port pB1 and the low pressure port pC as shown in FIG. 5(e) (third rotational position RP3).

The first seal portion 43 is a portion of the sliding surface 41 that is continuous with one end of the fluid passage 42 . The first seal portion 43 is formed so as to close the first input/output port pB1 when passing through the first input/output port pB1. The first seal portion 43 is also formed to close the second input/output port pB2 when passing through the second input/output port pB2.

The second seal portion 44 is a portion of the sliding surface 41 that is continuous with the other end of the fluid passage 42 . The second seal portion 44 is formed so as to close the first input/output port pB1 when passing through the first input/output port pB1.

In this embodiment, the first seal portion 43 completely closes the first input/output port pB1 and the second input/output port pB2 at a predetermined position. In addition to this, the first seal portion 43 ensures a slight bypass flow rate (the flow rate of the refrigerant flowing between the valve chamber 24 and the fluid passage 42 via the first input/output port pB1 or the second input/output port pB2). In this way, the first input/output port pB1 and the second input/output port pB2 may be closed with a small gap left. The same applies to the second seal portion 44.

The high pressure port pA is always open to the valve chamber 24. High pressure refrigerant flows through the valve chamber 24 . Low pressure port pC is always open to fluid passage 42. A low-pressure refrigerant flows through the fluid passage 42 . The first input/output port pB1 and the second input/output port pB2 open into the valve chamber 24 or the fluid passage 42 depending on the rotational position of the rotary valve body 40.

The base piston 50 is configured to have a substantially cylindrical shape by combining two members (resin members 50a and 50b). A male thread is provided on the resin member 50a. A female thread is provided in the resin member 50b. The resin member 50a and the resin member 50b are assembled by tightening screws. An O-ring 51, which is a sealing member, is held in a groove formed between the resin members 50a and 50b. The outer diameter of the base piston 50 is the same as or slightly smaller than the inner diameter of the base piston accommodating portion 11 . An O-ring 51 is arranged between the base piston 50 and the base piston accommodating portion 11.

The base piston 50 is movable between a first base position BP1 and a second base position BP2. The first base position BP1 is a position where the base piston 50 contacts the wall portion 14, as shown in FIG. The second base position BP2 is a position where the base piston 50 contacts the stopper surface 16 of the main body case 10, as shown in FIGS. 3 and 4. The second base position BP2 is closer to the other end 10b than the first base position BP1.

The driving piston 60 is configured to have a substantially cylindrical shape by combining two members (resin members 60a and 60b). A male thread is provided on the resin member 60a. A female thread is provided in the resin member 60b. The resin members 60a and 60b are assembled by tightening screws. An O-ring 61, which is a sealing member, is held in a groove formed between the resin members 60a and 60b. Note that other types of sealing members may be used instead of the O-rings 51 and 61. The drive piston 60 has a smaller diameter than the base piston 50. The outer diameter of the drive piston 60 is the same as or slightly smaller than the inner diameter of the drive piston accommodating portion 12 . An O-ring 61 is disposed between the driving piston 60 and the driving piston accommodating portion 12. The diameter of the portion sealed by the O-ring 61 is smaller than the diameter of the portion sealed by the O-ring 51. A guide hole 62 is provided in the end surface of the drive piston 60 on the other end 10b side. The guide hole 62 has a polygonal cross-sectional shape (for example, a regular hexagonal shape) in a direction perpendicular to the axis L. The bearing 18 is fitted into the guide hole 62. The bearing 18 is relatively movable in the direction of the axis L inside the guide hole 62. The driving piston 60 is restricted from rotating around the axis L by the bearing 18 . A female threaded surface 63 is provided inside the driving piston 60 .

The driving piston 60 is movable between a first stop position SP1, a second stop position SP2, and a third stop position SP3. The first stop position SP1 is, as shown in FIG. 2, a position where the driving piston 60 contacts the base piston 50 located at the first base position BP1. The second stop position SP2 is, as shown in FIG. 3, a position where the driving piston 60 contacts the base piston 50 located at the second base position BP2. The third stop position SP3 is a position where the driving piston 60 is separated from the base piston 50 and contacts the stopper surface 19 of the bearing 18, as shown in FIG. The third stop position SP3 is closer to the other end 10b than the second stop position SP2.

The power transmission mechanism 70 has a rotational drive shaft 71 and a valve shaft 75. The rotational drive shaft 71 is formed into a substantially cylindrical shape. A male threaded surface 73 is provided on the outer peripheral surface of the rotary drive shaft 71. The rotation drive shaft 71 is arranged such that the male threaded surface 73 is in contact with the female threaded surface 63 of the driving piston 60. The male threaded surface 73 and the female threaded surface 63 are screwed together. When the driving piston 60 moves in the direction of the axis L, the rotary drive shaft 71 is rotated around the axis L by the screw feeding action of the female threaded surface 63 and the male threaded surface 73. The valve shaft 75 is formed into a substantially cylindrical shape. The valve shaft 75 is inserted through the bearing 18. The valve shaft 75 is supported by the bearing 18 so as to be rotatable around the axis L. An O-ring 76, which is a sealing member, is arranged between the valve shaft 75 and the bearing 18. Note that other types of sealing members may be used instead of the O-ring 76. The valve shaft 75 is attached coaxially to the rotary valve body 40. A coil spring 77 is arranged between the valve shaft 75 and the rotary valve body 40 to apply a force to the rotary valve body 40 to press it against the valve seat 30. An end portion of the valve shaft 75 on the one end 10 a side is attached to the rotary drive shaft 71 . The valve shaft 75 is rotated together with the rotary drive shaft 71. When the valve shaft 75 is rotated, the rotary valve body 40 is also rotated. The power transmission mechanism 70 may include a speed reduction mechanism including a plurality of gears between the rotary drive shaft 71 and the valve shaft 75.

The respective axes of the main body case 10, the valve seat 30, the rotary valve body 40, the base piston 50, the driving piston 60, the rotary drive shaft 71, and the valve shaft 75 coincide with the axis L. That is, they are all arranged coaxially.

The base piston control valve 80 is an electromagnetic valve that includes a coil 81 , a plunger 82 that moves according to a magnetic field generated by the coil 81 , and a valve body 83 connected to the plunger 82 . The valve body 83 is arranged on the valve seat 84. The valve seat 84 has a first port 85 and a second port 86. The first port 85 is connected to the low pressure conduit C through the capillary tube S1. The second port 86 is connected to the first piston chamber 21 through the thin tube S2. The base piston control valve 80 has a valve chamber 88 connected to the high pressure conduit A through a capillary tube S3.

In a state where the coil 81 is not energized (base piston control valve 80: OFF), the valve body 83 is moved to a position where the first port 85 and the second port 86 are connected. The base piston control valve 80 is in the first base position connection state connecting the first piston chamber 21 and the low pressure conduit C. In the connected state for the first base position, the base piston 50 moves toward the end 10a and is positioned at the first base position BP1.

With the coil 81 energized (base piston control valve 80: on), the valve body 83 is moved to a position covering only the first port 85, and the second port 86 opens into the valve chamber 88. The base piston control valve 80 is in the connected state for the second base position connecting the first piston chamber 21 and the high pressure conduit A. In the second base position connected state, the base piston 50 moves toward the other end 10b and is positioned at the second base position.

The driving piston control valve 90 is an electromagnetic valve that includes a coil 91 , a plunger 92 that moves in response to a magnetic field generated by the coil 91 , and a valve body 93 connected to the plunger 92 . The valve body 93 is arranged on the valve seat 94. The valve seat 94 has a first port 95, a second port 96, and a third port 97. The first port 95 is connected to the third piston chamber 23 through the thin tube T1. The second port 96 is connected to the low pressure conduit C through a capillary tube T2. The third port 97 is connected to the second piston chamber 22 through the thin tube T3. The driving piston control valve 90 has a valve chamber 98 connected to the high pressure conduit A through a thin tube T4.

The valve body 93 is moved to a position connecting the second port 96 and the third port 97 with the coil 91 not energized (driving piston control valve 90: OFF), and the first port 95 is connected to the valve chamber 98. Open your mouth. The driving piston control valve 90 is in a contact position connection state where the second piston chamber 22 and the low pressure conduit C (low pressure port pC) are connected and the third piston chamber 23 and the high pressure conduit A (high pressure port pA) are connected. becomes. In the contact position connected state, one end of the driving piston 60 moves toward the 10 a side, and the driving piston 60 comes into contact with the base piston 50 . The driving piston 60 is positioned at the first stop position SP1 or the second stop position SP2 depending on the position of the base piston 50.

With the coil 91 energized (driving piston control valve 90: on), the valve body 93 is moved to a position connecting the first port 95 and the second port 96, and the third port 97 is connected to the valve chamber 98. Open your mouth. The driving piston control valve 90 is in a connection state for a separated position, in which the second piston chamber 22 and the high pressure conduit A (high pressure port pA) are connected, and the third piston chamber 23 and the low pressure conduit C (low pressure port pC) are connected. becomes. In the connection state for the separated position, the driving piston 60 moves toward the other end 10b, and the driving piston 60 separates from the base piston 50. The driving piston 60 is positioned at the third stop position SP3.

An example of the operation of the flow path switching system 1 will be described with reference to FIGS. 2 to 5. 5(a) to 5(e) are cross-sectional views taken along the valve seat surface 31 (the location indicated by the line XX in FIG. 1). In FIGS. 5(a) to 5(e), the sliding surface 41 is schematically shown by hatching.

In the flow path switching system 1, high-pressure refrigerant discharged from the discharge port of the compressor flows into the high-pressure conduit A. A low-pressure refrigerant flowing toward the suction port of the compressor flows through the low-pressure conduit C. The flow path switching system 1 provides the following three flow path connection patterns.

Pattern 1: Connect the first input/output port pB1, the second input/output port pB2, and the low pressure port pC.
Pattern 2: High pressure port pA and first input/output port pB1 are connected, and second input/output port pB2 and low pressure port pC are connected.
Pattern 3: Connect high pressure port pA and second input/output port pB2, and connect first input/output port pB1 and low pressure port pC.

(Pattern 1)
Turn off base piston control valve 80. Turn off the driving piston control valve 90. The base piston control valve 80 connects the first piston chamber 21 and the low pressure conduit C. The driving piston control valve 90 connects the second piston chamber 22 and the low pressure conduit C. The third piston chamber 23 and the high pressure conduit A are connected by the driving piston control valve 90 . As a result, low-pressure refrigerant is introduced into the first piston chamber 21 . A low pressure refrigerant is introduced into the second piston chamber 22 . High pressure refrigerant is introduced into the third piston chamber 23 .

Since the refrigerant in the first piston chamber 21 and the refrigerant in the second piston chamber have the same pressure, no force is generated to move the base piston 50 due to the refrigerant pressure. The differential pressure between the refrigerant in the second piston chamber 22 and the refrigerant in the third piston chamber 23 generates a force F1 that moves the driving piston 60 toward the one end 10a. The driving piston 60 moves toward one end 10a and comes into contact with the base piston 50. The base piston 50 is pushed by the driving piston 60, moves toward the one end 10a, and abuts against the wall portion 14. As a result, as shown in FIG. 2, the base piston 50 is positioned at the first base position BP1, and the driving piston 60 is positioned at the first stop position SP1. Then, in accordance with the movement of the driving piston 60, the rotary valve body 40 is positioned at the first rotational position RP1 shown in FIG. 5(a). In the state shown in FIG. 5(a), the first input/output port pB1, the second input/output port pB2, and the low pressure port pC are connected by the fluid passage 42. The high pressure port pA is not connected to any of the first input/output port pB1, the second input/output port pB2, and the low pressure port pC.

(Pattern 2)
In the state shown in FIG. 5(a), the base piston control valve 80 is turned on. Turn off the driving piston control valve 90. The base piston control valve 80 connects the first piston chamber 21 and the high pressure conduit A. The driving piston control valve 90 connects the second piston chamber 22 and the low pressure conduit C. The third piston chamber 23 and the high pressure conduit A are connected by the driving piston control valve 90 . As a result, high-pressure refrigerant is introduced into the first piston chamber 21 . A low pressure refrigerant is introduced into the second piston chamber 22 . High pressure refrigerant is introduced into the third piston chamber 23 .

The pressure difference between the refrigerant in the first piston chamber 21 and the refrigerant in the second piston chamber generates a force F2 that moves the base piston 50 toward the other end 10b. The differential pressure between the refrigerant in the second piston chamber 22 and the refrigerant in the third piston chamber 23 generates a force F1 that moves the driving piston 60 toward the one end 10a. The outer diameter of the driving piston 60 is smaller than the outer diameter of the base piston 50. Therefore, force F1 is smaller than force F2. The base piston 50 moves toward the other end 10b and abuts against the stopper surface 16. The driving piston 60 is pushed by the base piston 50 and moves toward the other end 10b. As a result, as shown in FIG. 3, the base piston 50 is positioned at the second base position BP2, and the driving piston 60 is positioned at the second stop position SP2. Then, in accordance with the movement of the driving piston 60, the rotary valve body 40 moves from the first rotational position RP1 shown in FIG. 5(a) to the rotational position shown in FIG. It is positioned at the second rotational position RP2 shown in FIG. In the state shown in FIG. 5(c), the high pressure port pA and the first input/output port pB1 are connected by the valve chamber 24. The second input/output port pB2 and the low pressure port pC are connected by a fluid passage 42.

While the rotary valve body 40 is moving from the first rotational position RP1 to the second rotational position RP2, the first input/output port pB1 is removed from the fluid passage 42 and the first seal portion 43 is moved, as shown in FIG. 5(b). It is blocked by. Then, when the rotary valve body 40 moves to the second rotational position RP2, the first input/output port pB1 opens into the valve chamber 24. Thereby, the fluid passage 42 and the valve chamber 24 are not connected through the first input/output port pB1 while the rotary valve body 40 is moving from the first rotation position RP1 to the second rotation position RP2. Therefore, it is possible to suppress the high pressure refrigerant in the valve chamber 24 from moving to the low pressure side.

(Pattern 3)
In the state shown in FIG. 5(c), the base piston control valve 80 is turned on. Turn on the driving piston control valve 90. The base piston control valve 80 connects the first piston chamber 21 and the high pressure conduit A. The second piston chamber 22 and the high pressure conduit A are connected by the drive piston control valve 90 . The third piston chamber 23 and the low pressure conduit C are connected by the driving piston control valve 90 . As a result, high-pressure refrigerant is introduced into the first piston chamber 21 . High pressure refrigerant is introduced into the second piston chamber 22 . A low-pressure refrigerant is introduced into the third piston chamber 23 .

Since the refrigerant in the first piston chamber 21 and the refrigerant in the second piston chamber have the same pressure, no force is generated to move the base piston 50 due to the refrigerant pressure. The differential pressure between the refrigerant in the second piston chamber 22 and the refrigerant in the third piston chamber 23 generates a force F3 that moves the driving piston 60 toward the other end 10b. The driving piston 60 moves toward the other end 10b and abuts against the stopper surface 19. As a result, as shown in FIG. 4, the base piston 50 is positioned at the second base position BP2, and the driving piston 60 is positioned at the third stop position SP3. Then, in accordance with the movement of the driving piston 60, the rotary valve body 40 moves from the second rotational position RP2 shown in FIG. 5(c) to the rotational position shown in FIG. It is positioned at the third rotational position RP3 shown in FIG. In the state shown in FIG. 5(e), the high pressure port pA and the second input/output port pB2 are connected by the valve chamber 24. The first input/output port pB1 and the low pressure port pC are connected by a fluid passage 42.

While the rotary valve body 40 is moving from the second rotational position RP2 to the third rotational position RP3, the first input/output port pB1 is removed from the valve chamber 24 and the second seal portion 44 is moved, as shown in FIG. 5(d). It is blocked by. The second input/output port pB2 is removed from the fluid passage 42 and is closed by the first seal portion 43. Then, when the rotary valve body 40 moves to the third rotational position RP3, the first input/output port pB1 opens to the fluid passage 42. The second input/output port pB2 opens into the valve chamber 24. As a result, while the rotary valve body 40 is moving from the second rotational position RP2 to the third rotational position RP3, the fluid passage 42 and the valve chamber 24 are connected through the first input/output port pB1 and the second input/output port pB2. Never. Therefore, it is possible to suppress the high pressure refrigerant in the valve chamber 24 from moving to the low pressure side.

From the above, the flow path switching valve 5 of the flow path switching system 1 of the present embodiment has the base piston 50 at the first base position BP1 and at the second base position BP2, which is closer to the other end 10b than the first base position BP1. It is possible to move between . The driving piston 60 has a first stop position SP1 in contact with the base piston 50 at the first base position BP1, a second stop position SP2 in contact with the base piston 50 in the second base position BP2, and a second stop position SP2 in contact with the base piston 50 in the second base position BP2. It is movable between a third stop position SP3 on the other end 10b side. The base piston 50 and the driving piston 60 are moved in the direction of the axis L according to the refrigerant pressure in the first piston chamber 21 , the second piston chamber 22 , and the third piston chamber 23 . Since this is done, by switching the refrigerant pressures in the first piston chamber 21, the second piston chamber 22, and the third piston chamber 23, the base piston 50 can be positioned at the first base position BP1 and the second base position BP2. , the drive piston 60 is positioned at a first stop position SP1 and a second stop position SP2 in contact with the base piston 50, and a third stop position SP3 away from the base piston 50. Therefore, the rotary valve body 40 is rotated in accordance with the movement of the driving piston 60 in the axis L direction, and the rotary valve body 40 is rotated to a first rotational position RP1 corresponding to the first stop position SP1, the second stop position SP2, and the third stop position SP3. , are positioned at a second rotational position RP2 and a third rotational position RP3. Therefore, three flow path connection patterns can be provided using refrigerant pressure.

Further, the sliding surface 41 of the rotary valve body 40 is formed into an arc shape in plan view. The sliding surface 41 is provided with a fluid passage 42, a first seal portion 43, and a second seal portion 44. The fluid passage 42 is a concave portion having an arcuate shape in a plan view to which the first input/output port pB1, the second input/output port pB2, and the low pressure port pC can be connected. The first seal portion 43 is a portion of the sliding surface 41 that continues to one end of the fluid passage 42 . The first seal portion 43 is formed so as to close the first input/output port pB1 when passing through the first input/output port pB1. The first seal portion 43 is also formed to close the second input/output port pB2 when passing through the second input/output port pB2. The second seal portion 44 is a portion of the sliding surface 41 that continues to the other end of the fluid passage 42 . The second seal portion 44 is formed so as to close the first input/output port pB1 when passing through the first input/output port pB1. Because of this, when rotating the rotary valve body 40 to switch the flow path, the fluid passage 42 and the valve chamber 24 are not connected through the first input/output port pB1 and the second input/output port. Therefore, it is possible to suppress the high pressure refrigerant in the valve chamber 24 from moving to the low pressure side.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. Additions, deletions, and design changes to the above-mentioned embodiments by those skilled in the art as appropriate, as well as combinations of features of the embodiments as appropriate, are also within the scope of the present invention, as long as they do not go against the spirit of the present invention. included in the range.

DESCRIPTION OF SYMBOLS 1... Flow path switching system, 5... Flow path switching valve, 10... Main body case, 10a... One end, 10b... Other end, 11... Base piston accommodating part, 12... Drive piston accommodating part, 13... Valve body accommodating part, 14, 15... Wall portion, 16... Stopper surface, 17... Partition wall, 18... Bearing, 19... Stopper surface, 21... First piston chamber, 22... Second piston chamber, 23... Third piston chamber, 24... Valve chamber , 30... Valve seat, 31... Valve seat surface, 40... Rotating valve body, 41... Sliding surface, 42... Fluid passage, 43... First seal part, 44... Second seal part, 50... Base piston, 50a, 50b...Resin member, 51...O ring, 60...Drive piston, 60a, 60b...Resin member, 61...O ring, 62...Guide hole, 63...Female thread surface, 70...Power transmission mechanism, 71...Rotary drive shaft, 73...Male thread surface, 75...Valve shaft, 76...O ring, 77...Coil spring, 80...Base piston control valve, 81...Coil, 82...Plunger, 83...Valve body, 84...Valve seat, 85...First Port, 86...Second port, 88...Valve chamber, 90...Drive piston control valve, 91...Coil, 92...Plunger, 93...Valve body, 94...Valve seat, 95...First port, 96...Second Port, 97...Third port, 98...Valve chamber, pA...High pressure port, pB1...First input/output port, pB2...Second input/output port, pC...Low pressure port, A...High pressure conduit, B1...First input/output conduit, B2 ...Second input/output conduit, C...Low pressure conduit, S1-S3...Thin tube, T1-T4...Thin tube

Claims (3)

A cylindrical main case with one end closed,
a valve seat arranged to close the other end of the main body case;
a rotary valve body that switches connections between a plurality of ports provided on the valve seat;
a base piston arranged to be movable in the axial direction inside the main body case;
a driving piston having a smaller diameter than the base piston, the drive piston being disposed inside the main body case so as to be movable in the axial direction and being disposed closer to the other end than the base piston;
A flow path switching valve including a power transmission mechanism that rotates the rotary valve body in response to movement of the driving piston in the axial direction,
The main body case includes a first piston chamber, a second piston chamber, and a third piston chamber, which are partitioned by the base piston and the driving piston and arranged in order from the one end side toward the other end side. have,
The base piston is movable between a first base position and a second base position located closer to the other end than the first base position,
The drive piston has a first stop position where it contacts the base piston at the first base position, a second stop position where it contacts the base piston at the second base position, and a second stop position where it contacts the base piston at the second base position. It is movable between a third stop position on the end side,
The flow path switching valve is characterized in that the base piston and the driving piston are moved in the axial direction according to fluid pressures in the first piston chamber, the second piston chamber, and the third piston chamber. A surface of the rotary valve body in contact with the valve seat is formed in an arc shape or a fan shape in a plan view,
On the surface of the rotary valve body in contact with the valve seat, there is a fluid passage which is an arc-shaped recess in a plan view to which the plurality of ports can be connected; The flow path switching valve according to claim 1, further comprising a seal portion that closes the port. A flow path switching system comprising the flow path switching valve according to claim 1 or 2, a base piston control valve, and a driving piston control valve,
The base piston control valve is
a first base position connection state connecting the first piston chamber and a low pressure port of the plurality of ports through which low pressure fluid flows;
switching between a second base position connection state that connects the first piston chamber and a high-pressure port of the plurality of ports through which high-pressure fluid flows;
The driving piston control valve is
a contact position connection state connecting the second piston chamber and the low pressure port and connecting the third piston chamber and the high pressure port;
A flow path switching system characterized by switching between a connection state for a separation position in which the second piston chamber and the high pressure port are connected and the third piston chamber and the low pressure port are connected.

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