JP2011241870A - Flow path switching valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the durability of a piston 2 by quickly equalizing a pressure of a main valve chamber 11A and a sub valve chambers 12A after the piston 2 moves, concerning the flow path switching valve 10 constituted by partitioning the inside of a valve housing 1 to a main valve chamber 11A and sub valve chambers 12A, 12A in both sides thereof by two pistons 2, 2, moving the pistons 2 and the main valve body 5 by a differential pressure to the coolant pressure in the main valve chamber 11A by lowering the pressure in one sub valve chamber 12A, thereby switching the flow path of the coolant of a cooling cycle.SOLUTION: A pressure equalizing path is provided in the center of the piston 2, and a sub valve 25 is disposed in the pressure equalizing path. When the piston 2 is moved toward a cap 12, the sub valve 25 closes an opening of an exhaust path 12a at a sub valve seat 122, and opens the pressure equalizing path.

Description

  The present invention relates to a flow path switching valve that is used in a refrigeration cycle such as an air conditioner and switches a refrigerant flow path.

  Conventionally, in an air conditioner or the like, the cooling operation and the heating operation are switched by switching the refrigerant flow path of the refrigeration cycle. In such a refrigeration cycle, a compressor, two heat exchangers used as a condenser or an evaporator, and a flow path switching valve for switching a flow path of refrigerant between the compressor and the two heat exchangers Is used.

  An example of this type of flow path switching valve is disclosed in Japanese Patent Application Laid-Open No. 2009-68695 (Patent Document 1). The flow path switching valve accommodates a piston body in which two pistons and a main valve body are connected in a cylindrical valve housing (valve body), and the main valve body is an axis with respect to a valve seat in the valve housing. The flow path of the refrigerant flowing in the plurality of pipes by sliding in the direction is switched. When the flow path is switched, the piston body is moved by the differential pressure between the refrigerant pressure in the main valve chamber between the two pistons and the refrigerant pressure in the sub valve chamber outside the piston.

Moreover, when the piston main body is moved, the flow path switching valve of Patent Document 1 causes the second valve element (ball) disposed on the piston to contact a valve seat provided on the end cap of the valve housing, By closing the extraction pipe provided in the valve seat, the high-pressure side main valve chamber and the low-pressure side sub-valve chamber are equalized, and the differential pressure acting on the piston packing is reduced. Thus, the durability of the piston is obtained even when the fluid is a super high pressure refrigerant such as CO ₂ .

JP 2009-68695 A

  In the flow path switching valve of Patent Document 1, an annular inclined portion is provided around the piston packing, and the sectional shape gradually inclines toward the inner surface of the valve housing as it goes toward the end of the valve housing. It has a shape. When the main valve chamber side is in a high pressure state, the sub valve chamber side is in a low pressure state, and after the extraction valve is closed by the second valve body, The high-pressure refrigerant is configured to leak into the auxiliary valve chamber from between the inclined portion of the packing and the inner surface of the valve housing. For this reason, it is difficult to equalize the pressure between the main valve chamber and the sub valve chamber smoothly, leaving room for improvement.

  The present invention has been made to solve the above-described problems. In the tubular valve housing, two pistons and a main valve body are connected and accommodated, and a main valve chamber inside the piston is provided. The main valve body is moved in a flow path switching valve that switches the flow path of the refrigerant flowing through the plurality of pipes by sliding the main valve body with respect to the valve seat by the pressure difference between the refrigerant and the sub-valve chamber outside the piston. It is an object to later obtain the durability of the piston by surely equalizing the main valve chamber and the sub valve chamber.

  The flow path switching valve according to claim 1 accommodates two pistons disposed on an axis of the valve housing and connected to each other in a cylindrical valve housing, and the inside of the valve housing is connected to the high pressure side by the two pistons. A main valve seat that is partitioned into a central main valve chamber to which piping is connected and two sub-valve chambers on both sides of the main valve chamber, and that is connected to the low-pressure side piping and the two switching side pipings is provided in the main valve chamber. And disposing a main valve body slidable in the axial direction relative to the main valve seat, connected to the piston, and introducing a high-pressure refrigerant into one of the two sub valve chambers, By depressurizing the other sub-valve chamber, the piston and the main valve body are moved to the sub-valve chamber side by the differential pressure between the decompressed sub-valve chamber and the main valve chamber, The low-pressure side pipe is selectively communicated with one of the two switching-side pipes by a recess. And the other switching side pipe is connected to the high pressure side pipe via the main valve chamber, and the flow path switching valve for switching the flow of the refrigerant projects to the main valve chamber side at both ends inside the valve housing. A sub-valve seat portion, which is a sub-valve seat portion and has an extraction passage serving as a passage for the refrigerant opened in the valve housing, is formed on each piston, on the axis corresponding to the sub-valve seat portion, A pressure equalizing passage that allows the main valve chamber and the sub valve chamber to communicate with each other is formed, and is a sub valve disposed in the pressure equalizing passage, and is moved by the axial movement with respect to the pressure equalizing passage. A sub-valve for switching between conduction and blockage of the pressure equalizing passage is provided, and when the piston has finished moving to the depressurized sub-valve chamber side, the sub-valve of the piston is moved to the sub-valve chamber side. The opening of the auxiliary valve seat is closed, and the auxiliary valve seat is connected to the auxiliary valve. Conducting the pressure equalizing path by contact, and said decompressed sub valve chamber via a the homogeneous pressure passage the main valve chamber, characterized in that as pressure equalizing.

  The flow path switching valve according to claim 2 is the flow path switching valve according to claim 1, wherein the piston has a packing that contacts an inner surface of the valve housing, and a center of the valve housing is provided on an outer periphery of the packing. An inclined portion extending in an annular shape is formed on the side of the portion, and the inclined portion has a shape in which the cross-sectional shape is gradually inclined toward the inner surface of the valve housing toward the central portion of the valve housing. .

According to the flow path switching valve of the first aspect, when the piston finishes moving to the decompressed sub valve chamber side, the piston sub valve closes the opening of the sub valve seat on the sub valve chamber side. The decompression of the auxiliary valve chamber is stopped, and the auxiliary valve seat is brought into contact with the auxiliary valve to conduct the pressure equalizing passage, and the refrigerant flows from the main valve chamber to the auxiliary valve chamber through the pressure equalizing passage. The pressure equalization between the chamber and the auxiliary valve chamber is performed smoothly. Thus, the pressure load applied to the seal member of the piston when not moving is eliminated, and creep deformation of the seal member can be prevented. In addition, stress deformation of members constituting the piston can be prevented. Therefore, it is particularly suitable as a flow path switching valve using an ultrahigh pressure refrigerant such as a CO ₂ refrigerant.

  According to the flow path switching valve of the second aspect, in addition to the effect of the first aspect, when the sub valve chamber side is depressurized, in the piston between the depressurized sub valve chamber and the high pressure main valve chamber The high-pressure refrigerant on the main valve chamber side acts to press the inclined portion of the packing against the inner surface of the valve housing, so that the sub-valve chamber decompressed by the packing and the high-pressure main valve chamber are securely sealed. Therefore, the moving operation of the piston and the main valve body is ensured.

It is a figure which shows the flow-path switching valve, pilot valve, and refrigeration cycle of embodiment of this invention. It is principal part sectional drawing of the flow-path switching valve of embodiment. It is principal part action explanatory drawing of the flow-path switching valve of embodiment. It is principal part sectional drawing of the pilot valve in embodiment. It is a timing chart which shows the example of a drive of the pilot valve in an embodiment. It is principal part sectional drawing which shows the other example of the piston of the flow-path switching valve in embodiment.

  Next, an embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a flow path switching valve, a pilot valve, and a refrigeration cycle according to an embodiment. The flow path switching valve 10 of this embodiment is a four-way switching valve, and the flow path switching valve 10 is connected to the pilot valve 20 by piping. In the flow path switching valve 10, the valve housing 1 has a cylindrical shape, and includes a cylindrical portion 11 having a cylindrical shape and two cap portions 12 and 12 having a disk shape. The cap parts 12, 12 are each attached to the cylindrical part 11 by welding or the like so as to close the end of the cylindrical part 11, and the central axis of the cylindrical part 11 and the cap parts 12, 12 is the axis L 1 of the valve housing 1. ing. A thin circular concave portion 121 is formed on the cylindrical portion 11 side of the cap portions 12 and 12.

  In the valve housing 1, two pistons 2, 2 arranged on the axis L of the valve housing 1 and connected to each other by a connecting member 3 are accommodated. As a result, the inside of the valve housing 1 constituted by the inside of the cylindrical portion 11 and the circular recesses 121 and 121 of the cap portions 12 and 12 is connected to the main valve chamber 11A and the main valve chamber at the center by the two pistons 2 and 2. It is partitioned into two auxiliary valve chambers 12A and 12A on both sides of 11A.

  A main valve seat 4 is disposed at an intermediate portion in the main valve chamber 11A, and a main valve body 5 that slides in the direction of the axis L1 of the valve housing 1 is disposed on the main valve seat 4. The main valve seat 4 is formed with an E port 4a, an S port 4b and a C port 4c in a straight line in the direction of the axis L1 of the valve housing 1, and these E port 4a, S port 4b and C port 4c Are respectively attached with an E joint pipe 13a, an S joint pipe 13b, and a C joint pipe 13c. Further, a D port 11a is formed at a position facing the main valve seat 4 in the middle of the cylindrical portion 11, and a D joint pipe 13d is attached to the D port 11a. The E joint pipe 13a and the C joint pipe 13c correspond to “switching side piping”, the S joint pipe 13b corresponds to “low pressure side piping”, and the D joint pipe 13d corresponds to “high pressure side piping”. Thereby, D joint pipe 13d as high-pressure side piping is connected to main valve chamber 11A, and main valve seat 4 is connected to low-pressure side piping and two switching-side piping.

  A valve body fitting hole 3a is formed in the center of the connecting member 3, and through holes 3b and 3c are formed on both sides thereof. The main valve body 5 is fitted into the valve body fitting hole 3a, and the main valve body 5 is held with a slight play in the direction of the axis L with respect to the connecting member 3. When the pistons 2 and 2 move, the main valve body 5 slides on the main valve seat 4 in conjunction with the connecting member 3 and stops at predetermined left and right positions.

  The main valve body 5 is formed by insert-molding a bowl-shaped metal plate 51 together with a resin member 52, and a main valve recess 5 </ b> A is formed inside the metal plate 51. The main valve body 5 communicates the S port 4b and the E port 4a with the main valve recess 5A at the left end position in FIG. At this time, the C port 4c communicates with the D port 11a mainly through the through hole 3c in the main valve chamber 11A. The main valve body 5 communicates the S port 4b and the C port 4c with the main valve recess 5A at the end position on the right side of FIG. At this time, the E port 4a communicates with the D port 11a mainly through the through hole 3b in the main valve chamber 11A.

  The S joint pipe 13b is connected to the suction port of the compressor 30 by a low pressure pipe 14a, and the D joint pipe 13d is connected to the discharge port of the compressor 30 by a high pressure pipe 14b. The C joint pipe 13c is connected to the outdoor unit 40 by a conduit 14c, and the E joint pipe 13a is connected to the indoor unit 50 by a conduit 14d. The outdoor unit 40 and the indoor unit 50 are connected to each other by a conduit 14e through a throttle device 60. A refrigeration cycle is constituted by a path including the outdoor unit 40, the expansion device 60, the indoor unit 50, and the E joint pipe 13a from the C joint pipe 13c, and a path including the compressor 30 and the D joint pipe 13d from the S joint pipe 13b. Has been.

  Then, as will be described later, the position of the main valve body 5 of the flow path switching valve 10 is switched by the pilot valve 20. The high-pressure refrigerant compressed by the compressor 30 flows into the main valve chamber 11A from the D joint pipe 13d via the D port 11a, and in the cooling operation state of FIG. 1, the high-pressure refrigerant passes from the C port 4c to the outdoor unit 40. Is flowed into. Further, in the heating operation state in which the main valve body 5 is switched, the high-pressure refrigerant flows into the indoor unit 50 from the E port 4a. That is, during the cooling operation, the refrigerant discharged from the compressor 30 circulates from the C joint pipe 13c → the outdoor unit 40 → the expansion device 60 → the indoor unit 50 → the E joint pipe 13a, and the outdoor unit 40 is a condenser (condenser), The indoor unit 50 functions as an evaporator (evaporator) and is cooled. Further, during the heating operation, the refrigerant is circulated in reverse, and the indoor unit 50 functions as a condenser and the outdoor unit 40 functions as an evaporator, and heating is performed. Note that “C” and “E” of the C port 4c and the E port 4a are names based on the cooling operation.

  Each cap 12, 12 is formed with a sub-valve seat 122 that protrudes inward at the center (on the axis L 1) of the circular recess 121. The cap portions 12 and 12 are formed with an exhaust passage 12a penetrating from the side portion to the end portion 122a of the sub valve seat portion 122, and conduits 15f and 15g are respectively connected to the exhaust passages 12a and 12a. It is connected.

  In FIG. 1, the pilot valve 20 includes two electromagnetic actuators. The pilot valve 20 has a block-shaped valve housing 61. Two plunger cases 62 and 62 are airtightly fixed to the valve housing 61. Further, at the end portions of the plunger cases 62 and 62, The suction elements 63 are fixed in an airtight manner. A plunger 65 is disposed inside the plunger cases 62 and 62. Electromagnetic coils 72 and 72 wound around bobbins 71 and 71 are provided on the outer peripheral portions of the attractors 63 and 63 and the plunger cases 62 and 62. Then, due to the excitation of the electromagnetic coil 72, the inner end surface of the attractor 63 becomes a magnetic adsorption surface for the plunger 65.

  A high pressure joint pipe 64d, a low pressure joint pipe 64b, and two switching joint pipes 64a and 64c are attached to the valve housing 61. The high pressure joint pipe 64d is connected to the D joint pipe 13d (high pressure side) of the four-way switching valve 10 by the conduit 14f, and the low pressure joint pipe 64b is connected to the S joint pipe 13b (low pressure side) of the four-way switching valve 10 by the conduit 14g. Yes. The switching joint pipes 64a and 64c are connected to the conduits 15f and 15g of the four-way switching valve 10 by conduits 14h and 14i, respectively. Note that the high-pressure joint pipe 64d, the low-pressure joint pipe 64b, the switching joint pipes 64a and 64c, and the conduits 14f, 14g, 14h, and 14i may be formed of the same member.

  FIG. 4 is a cross-sectional view showing details of a main part of the pilot valve 20. A cylindrical pilot valve chamber 61A is formed in the valve housing 61, and the plunger cases 62, 62 are fitted coaxially with respect to the axis L2 at both ends of the pilot valve chamber 61A. The plunger cases 62, 62 are cylindrical. A pilot valve seat 66 is mounted between the plunger cases 62 and 62 in the pilot valve chamber 61A, and slides in the direction of the axis L2 of the plunger cases 62 and 62 on the pilot valve seat 66. A pilot valve body 67 is provided. The pilot valve seat 66 is formed with a pilot switching port 61a, a pilot low pressure port 61b, and a pilot switching port 61c arranged in a straight line in the direction of the axis L2, and these pilot switching port 61a, pilot low pressure port 61b, pilot switching port are formed. The switching joint pipe 64a, the low-pressure joint pipe 64b, and the switching joint pipe 64c are attached to 61c. A pilot high pressure port 61d is formed at a position opposite to the pilot valve seat 66 in the middle of the valve housing 61, and the high pressure joint pipe 64d is attached to the pilot high pressure port 61d.

  In the plunger cases 62, 62, the plunger 65 is disposed so as to penetrate the pilot valve chamber 61A. The plunger 65 has a substantially cylindrical shape, and has a small-diameter portion 651 having a small central diameter, and large-diameter portions 652 and 652 having large diameters on both sides of the small-diameter portion 651 in alignment with the inner surfaces of the plunger cases 2 and 2. Yes. The plunger 65 has a D-cut surface 65 a that is partially cut parallel to the axis L <b> 2, and this D-cut surface 65 a faces the pilot valve seat 66. In the center of the small diameter portion 651, a valve body holding hole 65b is formed by cutting from the D cut surface 65a side, and a communication hole 65c communicating from the valve body holding hole 65b to the opposite side to the D cut surface 65a is formed. Yes. A pilot valve body 67 and a coil spring 68 are disposed in the valve body holding hole 65b.

  A pilot recess 67 a is formed in the pilot valve body 67 on the pilot valve seat 66 side. The pilot valve body 67 communicates the pilot switching port 61a and the pilot low pressure port 61b through the pilot recess 67a at the end position on the left side of FIG. At this time, the pilot switching port 61c communicates with the pilot high pressure port 61d through the periphery of the pilot valve chamber 61A and the small diameter portion 651. Further, the pilot valve body 67 communicates the pilot switching port 61c and the pilot low pressure port 61b through the pilot recess 67a at the end position on the right side of FIG. At this time, the pilot switching port 61a communicates with the pilot high pressure port 61d through the periphery of the pilot valve chamber 61A and the small diameter portion 651.

  Thus, the pilot valve 20 causes the plunger 65 to be attracted to the attractor 63 by energizing the electromagnetic coil 72 and causes the pilot valve body 67 to linearly move along the axis L2. As a result, the high-pressure refrigerant is supplied from the pilot switching port 61a to the left sub-valve chamber 12A of the four-way switching valve 10 and the right sub-valve chamber 12A is decompressed, and the right side of the four-way switching valve 10 from the pilot switching port 61c. The high-pressure refrigerant is supplied to the sub valve chamber 12A, and the state of depressurizing the left sub valve chamber 12A is switched to switch the flow path of the refrigeration cycle.

The pilot valve body 67 is pressed against the pilot valve seat 663 by the coil spring 68, and the sealing performance between the pilot valve body 67 and the pilot valve seat 66 is enhanced. The pilot valve seat 66 is a metal member, and the pilot valve body 67 is a resin member. For this reason, the sealing property between the pilot valve body 67 and the pilot valve seat 66 is further enhanced by the resin plasticity of the pilot valve body 67. This high sealing performance is particularly effective when using ultrahigh pressure CO ₂ as the refrigerant.

  FIG. 5 is a timing chart showing an example of energization control to the two electromagnetic coils 72 and 72. In FIG. 1, the left electromagnetic coil 72 is “coil A”, and the right electromagnetic coil 72 is “coil B”. As shown in FIG. 5A, when the coil A is energized (ON), the coil B is not energized (OFF). Thereby, the position of the pilot valve body 67 is located on the left side (the side of the energized electromagnetic coil 72). The pilot high-pressure port 61d and the pilot switching port 61c communicate with each other, and the pilot switching port 61a and the pilot low-pressure port 61b communicate with each other. Even if the coil A is not energized (OFF), the position of the pilot valve element 67 is maintained as it is. Next, when the coil A is not energized and the coil B is energized (ON), the pilot valve element 67 is positioned on the right side (the energized electromagnetic coil 72 side). The pilot high-pressure port 61d and the pilot switching port 61a communicate with each other, and the pilot switching port 61c and the pilot low-pressure port 61b communicate with each other. Even if the coil B is not energized (OFF), the position of the pilot valve element 67 is maintained as it is. As shown in FIG. 5 (B), the electromagnetic coil 72 is energized to switch the position of the pilot valve body 67, and then the holding voltage is applied until the next switching, so that the holding current flows. May be.

  In the pilot valve 20 of this embodiment, a plunger 65 for holding a pilot valve body 67 is disposed in two plunger cases 62 and 62 coaxially attached to a valve housing 61, and the pilot valve body 67 is connected to a plurality of joints. On the connected pilot valve seat 66, the plunger 65 is slidable together with the plunger 65 in the direction of the axis L2. The suction members 63, 63 are airtightly fixed to the end portions of the plunger cases 62, 62, and the suction members 63, 63 and Electromagnetic coils 72 and 72 are provided on the outer peripheral portions of the plunger cases 62 and 62, respectively. By energizing one of the electromagnetic coils 72 and 72 and de-energizing the other, the energized electromagnetic coil 72 is excited. The plunger 65 is adsorbed by the suction element 63, and the flow of the refrigerant in the plurality of pipes is switched by the pilot valve body 67. There.

  The pilot valve 20 of this embodiment is superior to, for example, the pilot valve disclosed in Japanese Patent Laid-Open No. 8-170865. This conventional pilot valve moves the pilot valve body to one side by energizing one electromagnetic actuator, cuts off the energization to the electromagnetic actuator, and moves the pilot valve body to the other by the biasing force of the spring. Yes. For this reason, due to the high differential pressure of the refrigerant acting on the pilot valve body, the driving force and spring force of the electromagnetic actuator had to be increased in order to drive the pilot valve body. In addition, the spring force hinders the force generated by the electromagnetic actuator, reducing the efficiency of the attractive force.

  On the other hand, the pilot valve 20 according to the embodiment includes two electromagnetic actuators that are opposed to each other without a spring, and the two electromagnetic actuators are switched to each other and driven to reduce the efficiency due to the spring force. And an inexpensive electromagnetic actuator can drive a pilot valve element on which a high differential pressure acts. In addition, in the state where the differential pressure is generated in the pilot valve body, the position of the pilot valve body does not change even if the coil is turned off. it can. Further, in the conventional device, when the attracting force is reduced at a weak voltage, a magnetic sound is generated due to a balance with the spring force. However, in the pilot valve 20 of the embodiment, since there is no spring, the magnetic sound is generated. Can be reduced.

  Thus, the pilot valve 20 flows the high-pressure refrigerant flowing in from the high-pressure joint pipe 64d out of the switching joint pipe 64a or the switching joint pipe 64c, and this high-pressure refrigerant flows in the left sub valve chamber 12A or the right sub valve in the four-way switching valve 10. It is supplied to the chamber 12A. At this time, the right side sub valve chamber 12A or the left side sub valve chamber 12A of the four-way switching valve 10 is electrically connected to the low pressure side via the low pressure joint pipe 64b. Thereby, in the four-way switching valve 10, the one sub-valve chamber 12A becomes high pressure and the other sub-valve chamber 12A is depressurized by the pilot valve 20. Note that high-pressure refrigerant is always supplied to the main valve chamber 11A. Accordingly, a differential pressure between the pressure of the decompressed sub valve chamber 12A and the high pressure of the main valve chamber 11A is applied to the decompressed piston 2 on the sub valve chamber 12A side, and the piston 2 and the main valve are mainly driven by this differential pressure. The body 5 moves to the sub-valve chamber 12A side where the pressure is reduced, and the position of the main valve body 5 is switched.

  Here, each piston 2, 2 has a mirror-symmetric structure in FIG. Hereinafter, the detailed structure will be described with reference to FIG. 2 taking the left piston 2 as an example. The piston 2 includes a fixed disc 21 fixed to the connecting member 3, a leaf spring 22, a packing 23, a disc-shaped stopper plate 24, a sub valve 25, and a coil spring 26. These members are arranged coaxially about the axis L1.

  The leaf spring 22 is formed of a thin metal plate that can be elastically deformed, and integrally includes a disc-shaped disc portion 221 and an inclined biasing portion 222. The outer diameter of the disc portion 221 is substantially the same as that of the fixed disc 21. The inclined urging portion 222 is formed in an annular shape and is provided over the entire circumference of the outer edge of the disc portion 221. The inclined urging portion 222 extends from the outer edge of the disc portion 221 toward the center side of the cylindrical portion 11 (valve housing 1). That is, the inclined urging portion 222 is inclined with respect to both the direction of the axis L1 and the radial direction in a direction in which the cross-sectional shape gradually approaches the inner surface of the valve housing 1 as it goes toward the center of the valve housing 1. ing.

  The packing 23 is made of a synthetic resin and integrally includes a disk-shaped disk portion 231 and an inclined portion 232. The outer diameter of the disc portion 231 is substantially the same as that of the fixed disc 21. The inclined portion 232 is formed in an annular shape and is provided over the entire circumference of the outer edge of the disc portion 231. The inclined portion 232 extends from the outer edge of the disc portion 231 toward the center side of the cylindrical portion 11 (valve housing 1). That is, the inclined portion 232 is inclined with respect to both the direction of the axis L1 and the radial direction in a direction in which the cross-sectional shape gradually approaches the inner surface of the valve housing 1 as it goes toward the center of the valve housing 1. .

  Thus, the leaf spring 22 and the packing 23 have substantially the same shape, the leaf spring 22 is disposed inside the packing 23, and the disk portions 221 and 231 are disposed between the fixed disc 21 and the stopper plate 24. It is sandwiched and fixed. The leaf spring 22 is elastic so that the end of the inclined biasing portion 222 on the side away from the disk portion 221 is in sliding contact with the inner surface of the valve housing 1 via the inclined portion 232 of the packing 23. Deformable. Further, the leaf spring 22 generates an elastic restoring force that urges the inclined portion 232 of the packing 23 that is separated from the inner surface of the valve housing 1 toward the inner surface of the valve housing 1. When the leaf spring 22 is incorporated in the valve housing 1 (cylindrical portion 11), the end of the inclined urging portion 222 on the side away from the disc portion 221 causes the inclined portion 232 of the packing 23 to be in the valve housing 1. Pressing toward the inner surface of Thereby, the packing 23 reliably seals with the inner peripheral surface of the cylindrical portion 11 against the high-pressure refrigerant in the main valve chamber 11A.

  In each piston 2, circular holes 21 a, 22 a, 23 a and 24 a are formed in the center in the fixed disk 21, the leaf spring 22, the packing 23 and the stopper plate 24, respectively. A circular hole 3d is formed on the fixed disk 21 side of the connecting member 3, and the hole 3d of the connecting member 3 communicates with the through hole 3b (the through hole 3c on the right side) through a passage 3e. is doing. Among these, the hole 3d of the connecting member 3, the hole 21a of the fixed disk 21, the hole 22a of the leaf spring 22, and the hole 23a of the packing 23 have substantially the same diameter, and the hole 24a of the stopper plate 24 has a smaller diameter. It has become. These holes 21a, 22a, 23a, 24a and 3d constitute a “pressure equalizing passage”, and the sub-valve 25 is arranged in the holes 21a, 22a, 23a, 24a and 3d with a gap on the outer periphery thereof. It is installed.

  The auxiliary valve 25 includes a cylindrical large-diameter portion 251, a cylindrical small-diameter portion 252, and a cylindrical boss 253. The large-diameter portion 251 is in the small-diameter portion 252 in the holes 21 a, 22 a, and 23 a. Is inserted into the hole 24a. Further, the coil spring 26 is fitted into the boss portion 253 in the hole 3 d of the connecting member 3, and the auxiliary valve 25 is urged toward the cap portion 12 by the coil spring 26. The large-diameter portion 251 and the small-diameter portion 252 form a step end face 25a by the boundary.

  The operation of the auxiliary valve 25 is as follows. As the low pressure is introduced into one of the sub-valve chambers 12A and the pressure difference between the main valve chamber 11A and the sub-valve chamber 12A is generated, the entire piston 2 including the sub-valve 25 is moved to the low-pressure side sub-valve chamber 12A (cap The piston 2 stops when the stopper plate 24 comes into contact with the cap portion 12 and starts moving toward the portion 12). In the process of moving the piston 2, the end portion (small diameter portion 252) of the auxiliary valve 25 first contacts the auxiliary valve seat portion 122. At this time, the extraction / exhaust passage 12a provided in the sub valve chamber 12A is closed. Even after the end of the auxiliary valve 25 comes into contact with the auxiliary valve seat 122, the pressure difference between the main valve chamber 11A and the auxiliary valve chamber 12A overcomes the biasing force of the coil spring 26, and the piston 2 further moves, and the cap portion. The movement is continued until the stopper plate 24 constituting the piston 2 comes into contact with 12. In this moving section, a gap is always generated between the step end surface 25a of the sub valve 25 and the stopper plate 24. Therefore, the refrigerant flows through the gap from the main valve chamber 11A toward the sub valve chamber 12A, thereby equalizing the level. Approaching pressure. In the piston 2, when the main valve chamber 11 </ b> A and the sub-valve chamber 12 </ b> A are equalized, the balance between the force of pushing back by the coil spring 26 and the force such as the friction force between the piston 2 and the inner periphery of the cylindrical portion 11 is balanced. It stops at the held position. In this state, when the counter valve chamber 12A on the opposite side is depressurized and the piston 2 moves away from the cap portion 12, the stopper plate 24 is in contact with the valve seat 122 by the biasing force of the coil spring 26. The piston 2 including the auxiliary valve 25 continues to move after coming into contact with the step end face 25a.

  FIG. 3 is a view for explaining the action of the pressure equalizing passage constituted by the auxiliary valve 25 and the holes 21a, 22a, 23a, 24a and 3d. 3A shows a state in which the auxiliary valve 25 is separated from the auxiliary valve seat portion 122. In FIG. 1, the process in which the main valve body 5 moves to the right side, or the main valve body 5 moves to the left side from the center side of the valve housing 1. It corresponds to the process of moving to. At this time, the step end surface 25a of the auxiliary valve 25 is in contact with the stopper plate 24, and the conduction between the hole 24a of the stopper plate 24 and the hole 23a of the packing 23 and the hole 21a of the fixed disc 21 is interrupted. . That is, the pressure equalizing passage is closed.

  FIG. 3B corresponds to the state of FIG. 2 in which the auxiliary valve 25 is in contact with the auxiliary valve seat 122. At this time, the small diameter portion 252 of the auxiliary valve 25 closes the extraction / exhaust passage 12a of the auxiliary valve seat 122, and the stopper plate 24 is separated from the step end surface 25a of the auxiliary valve 25, so that the hole 24a of the stopper plate 24 is formed. The hole 23a of the packing 23, the hole 21a of the fixed disk 21 and the hole 3d of the connecting member 3 are electrically connected. That is, the pressure equalizing passage is in a conductive state. As a result, as indicated by the dashed arrows in FIG. 3B, the high-pressure refrigerant in the main valve chamber 11A is passed through the through-hole 3b (FIG. 2), the passage 3e, the hole 3d, and the fixed disk 21 of the connecting member 3. Through the hole 21 a, the hole 22 a of the leaf spring 22, the hole 23 a of the packing 23, and the hole 24 a of the stopper plate 24. And since the extraction exhaust passage 12a of the sub valve seat part 122 is obstruct | occluded, the pressure of the main valve chamber 11A and the sub valve chamber 12A equalizes, and the inflow of this refrigerant | coolant stops.

  As described above, since the pressure equalization between the main valve chamber 11A and the sub valve chamber 12A is promptly performed via the pressure equalization passage, it is possible to quickly shift to a state where the refrigerant pressure to the packing 23 is not affected. Further, in this embodiment, the inclined portion 232 of the packing 23 extends from the outer edge of the disc portion 231 toward the center side of the cylindrical portion 11, and its cross-sectional shape gradually increases toward the center side of the valve housing 1. Since it inclines in the direction approaching the inner surface of the valve housing 1, the high pressure of the main valve chamber 11A can be reliably maintained.

  FIG. 6 shows another embodiment of the piston. The same elements as those in FIG. The piston 2 ′ has a disc-shaped stopper plate 27 fixed to the connecting member 3 and a ring-shaped packing 28 slidably contacting the inner surface of the cylindrical portion 11 on the outer periphery of the stopper plate 27. Further, a large hole 27a corresponding to the large diameter portion 251 of the auxiliary valve 25 and a small hole 27b corresponding to the small diameter portion 252 are formed in the center of the stopper plate 27, and the auxiliary valve is formed in the large hole 27a and the small hole 27b. 25 is provided with a gap. The large hole 27a and the small hole 27b constitute a “pressure equalizing passage”. When the auxiliary valve 25 comes into contact with the auxiliary valve seat portion 122 and moves until the stopper plate 27 comes into contact with the cap portion 12, the end face of the boundary between the large hole 27 a and the small hole 27 b becomes the auxiliary valve 25 in this moving process. The pressure equalizing passage is separated from the step end face 25a and is brought into a conducting state. Further, when the stopper plate 27 is separated from the cap portion 12 from this state, the stopper plate 27 comes into contact with the step end surface 25a, and the pressure equalizing passage is closed. The operations of the auxiliary valve 25 and the pressure equalizing passage are the same as in the above embodiment.

  The above-described embodiment is particularly effective in the case of carbon dioxide having a high operating pressure as a refrigerant (fluid), but various refrigerants such as HCFC (hydro-chlorofluoro-carbon) and HFC (hydro-fluoro-carbon) are used. Also good. Further, in the present invention, the auxiliary valve 25 may be formed in a ball (ball) shape in addition to the embodiment described above, and the coil spring 26 urging the auxiliary valve 25 is replaced by a plate instead. A spring may be used.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Valve housing 2 Piston 3 Connecting member 4 Main valve seat 5 Main valve body 5A Main valve recessed part 11 Cylindrical part 11A Main valve chamber 12 Cap part 12A Sub valve chamber 12 Main valve seat 12a Extraction exhaust passage 122 Sub valve seat part 13a E joint Pipe 13b S joint pipe 13c C joint pipe 13d D joint pipe 25 Sub valve 21a Hole (equal pressure equalization passage)
22a Hole (equal pressure passage)
23a Hole (equal pressure passage)
24a Hole (equal pressure passage)
10 Channel Switching Valve 20 Pilot Valve 30 Compressor 40 Outdoor Unit 50 Indoor Unit 60 Throttle Device L1 Axis

Claims (2)

A central main valve in which two pistons arranged on the axis of the valve housing and connected to each other are accommodated in a cylindrical valve housing, and the high pressure side pipe is connected to the inside of the valve housing by the two pistons. A main valve seat that is divided into a chamber and two sub-valve chambers on both sides of the main valve chamber, and is connected to the low pressure side pipe and the two switching side pipes. A main valve body that is slidable in the axial direction is connected to the piston, introduces high-pressure refrigerant into one of the two sub-valve chambers, and depressurizes the other sub-valve chamber. The piston and the main valve body are moved to the sub valve chamber side by the pressure difference between the decompressed sub valve chamber and the main valve chamber, and the low pressure side pipe is connected to the two low pressure pipes by the recess of the main valve body. Selectively communicate with one of the switching side pipes and switch the other The pipe through the main valve chamber communicates with the high pressure side pipe, the flow path switching valve for switching the flow of the refrigerant,
A sub-valve seat portion that is a sub-valve seat portion that protrudes toward the main valve chamber and that opens a bleed exhaust passage serving as the refrigerant passage into the valve housing is formed at both ends inside the valve housing,
A pressure equalizing passage that allows the main valve chamber and the sub valve chamber to communicate with each other is formed on each of the pistons on the axis corresponding to the sub valve seat portion, and is disposed in the pressure equalizing passage. An auxiliary valve that switches between conduction and blocking of the pressure equalizing passage by movement in the axial direction with respect to the pressure equalizing passage,
When the piston has finished moving toward the decompressed sub valve chamber side, the sub valve of the piston closes the opening of the sub valve seat portion on the sub valve chamber side, and the sub valve seat portion The pressure equalizing passage is brought into conduction by contacting the subvalve so as to equalize the pressure-reduced subvalve chamber and the main valve chamber via the pressure equalizing passage. Road switching valve.   The piston has a packing that contacts the inner surface of the valve housing, and an inclined portion that extends in an annular shape is formed on the outer periphery of the packing toward the center portion of the valve housing, and the sectional shape of the inclined portion is that of the valve housing. A flow path switching valve characterized by having a shape that is gradually inclined toward the inner surface of the valve housing toward the center.

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