JP4451406B2 - Bidirectional constant pressure expansion valve - Google Patents

Description

  The present invention relates to a bidirectional constant pressure expansion valve that is connected between an outdoor heat exchanger and an indoor heat exchanger of a heat pump circuit, allows refrigerant to flow in both directions, and makes the refrigerant pressure on the downstream side constant.

  The conventional bidirectional constant pressure expansion valve shown in FIG. 6 has a pair of ball valve mechanisms 2 and 2 in the axial direction of the flow path 1 through which the refrigerant flows, and a movable body between the ball valve mechanisms 2 and 2. 3 is provided so that it can move linearly. The movable body 3 includes a bellows 4 extending in the linear motion direction, and a linear motion support mechanism 5 that restricts the buckling of the bellows 4 and supports the bellows 4 so that the bellows 4 can be expanded and contracted. The linear motion support mechanism 5 extends support protrusions 5B and 5B from movable plates 5A and 5A fixed to both ends of the bellows 4 so as to approach each other, and allows support pins 5C to pass through the support protrusions 5B and 5B. The supporting protrusions 5B and 5B are structured such that the supporting protrusions 5B and 5B can directly move relative to each other while restricting the relative inclination of the supporting protrusions 5B and 5B.

A pair of pressing shafts 6, 6 extend from both ends of the movable body 3 toward the ball valve mechanisms 2, 2, and each pressing shaft 6, 6 has a pressing force corresponding to the degree of expansion / contraction of the bellows 4. The balls 2A and 2A of the ball valve mechanisms 2 and 2 are pressed to adjust the valve opening of each ball valve mechanism 2. That is, for example, when the refrigerant flows from left to right in FIG. 6, the movable body 3 moves to the downstream side and comes into contact with the wall portion in the flow path 1, and one pressing shaft 6 is connected to the downstream side (in FIG. The ball valve mechanism 2 on the right side is held open. As a result, the refrigerant pressure on the downstream side of the ball valve mechanism 2 is applied to the bellows 4, and the other pressing shaft 6 is pressed upstream of the ball valve mechanism 2 on the upstream side (the left side in the figure) with a pressing force corresponding to the elastic force of the bellows 4. The ball 2A is pressed. Thereby, the ball valve mechanism 2 on the upstream side has a valve opening degree corresponding to the refrigerant pressure on the downstream side, and the downstream refrigerant can be kept at a constant pressure (see, for example, Patent Document 1).
Japanese Patent No. 3418271 (paragraphs [0024] to [0028], FIG. 1)

  However, the conventional bidirectional constant pressure expansion valve described above is expensive because the bellows 4 is used as the pressure sensitive member. Therefore, development of a bi-directional constant pressure expansion valve using a diaphragm, which is a pressure-sensitive member that is less expensive than a bellows, has been demanded.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bidirectional constant pressure expansion valve that can be manufactured at a lower cost than conventional ones.

  In order to achieve the above object, a bidirectional constant pressure expansion valve (10) according to the invention of claim 1 is provided between an indoor heat exchanger (92A) and an outdoor heat exchanger (91A) of a heat pump circuit (90). In a bidirectional constant pressure expansion valve (10) that is connected to the refrigerant and that allows the refrigerant to flow in both directions and to make the refrigerant pressure downstream, the body (10B) having a refrigerant flow path (11) therein. And a pair of opposing walls (13) that are provided in the body (10B) and divide the flow path (11) into one end side region (R1), an intermediate region (R3), and the other end side region (R2). And a pair of valve ports (16A, 16B) that are formed so as to penetrate the pair of opposing walls (13) and are arranged substantially coaxially, and the one end side region (R1) and the other end side region (R2). A pair of valve bodies (19) that are respectively disposed within and open and close each valve port (16A, 16B); A pair of valve body urging springs (17) for urging the valve body (19) toward the valve port (16A, 16B) and a pair of opposed walls (13) that are accommodated in the intermediate region (R3) The intermediate cylinder (31) that extends in the direction and can be linearly moved between the pair of opposing walls (13) and both ends of the intermediate cylinder (31) are closed, and the internal pressure in the intermediate region (R3) In response to the pair of diaphragms (34) deformed in response to the pair of valve ports (16A, 16B), the valve body (19) and the diaphragm (34) are stretched, and the diaphragm ( And a pair of abutting shafts (37) for changing the valve opening degree of the valve ports (16A, 16B) by moving the valve body (19) in accordance with the deformation amount of 34).

  The bidirectional constant pressure expansion valve (10) according to the invention of claim 2 is connected between the indoor heat exchanger (92A) and the outdoor heat exchanger (91A) of the heat pump circuit (90) so that the refrigerant is bidirectional. In the bidirectional constant pressure expansion valve (10) that is flowed and can make the downstream refrigerant pressure constant, the body (10B) having the refrigerant flow path (11) therein and the body (10B) are provided. A pair of opposing walls (13) that divide the flow path (11) into one end side region (R1), an intermediate region (R3), and the other end side region (R2), and a pair of opposing walls (13 ) And a pair of valve ports (16A, 16B) disposed substantially coaxially, and disposed in the one end side region (R1) and the other end side region (R2), respectively. A pair of valve bodies (19) for opening and closing the mouths (16A, 16B), and the valve bodies (19) are connected to the valve mouths (16A, 1 B) a pair of valve body urging springs (17) urging to the side, an intermediate cylinder (31) extending in the opposing direction of the pair of opposing walls (13) and fixed to the body (10B), Both ends of the intermediate cylinder (31) are closed and loosely fitted to a pair of diaphragms (34) and a pair of valve ports (16A, 16B) which are deformed according to the internal pressure of the intermediate region (R3). The valve body (19) and the diaphragm (34) are in a tension state, and the valve body (19) is moved according to the deformation amount of the diaphragm (34) to increase the valve opening of the valve ports (16A, 16B). It is characterized by having a pair of abutting shafts (37) to be changed.

  The invention of claim 3 is characterized in that in the bidirectional constant pressure expansion valve (10) according to claim 1 or 2, the elastic coefficients of the pair of diaphragms (34) are made different.

  According to a fourth aspect of the present invention, in the bidirectional constant pressure expansion valve (10) according to any one of the first to third aspects, a spring locking wall (31A) is provided at an axially intermediate portion of the inner surface of the intermediate cylinder (31). ), And a pair of pressure-sensitive auxiliary springs (32) are provided in a stretched state between the spring locking wall (31A) and both diaphragms (34).

  The invention of claim 5 is characterized in that in the bidirectional constant pressure expansion valve (10) according to claim 4, the elastic coefficients of the pair of pressure sensitive auxiliary springs (32) are made different.

  The invention of claim 6 is the bidirectional constant pressure expansion valve (10) according to any one of claims 1 to 5, wherein the opening area of the gap between one valve port (16A) and the contact shaft (37) is It is characterized in that it is wider than the opening area of the gap between the other valve port (16B) and the contact shaft (37).

  According to the bidirectional constant pressure expansion valve (10) of claim 1, the heat pump circuit (90) is in one of the cooling operation and the heating operation, and the refrigerant is in the one end side region (R1), the intermediate region (R3), When flowing in the order of the other end side region (R2), the intermediate cylinder (31) is pushed by the refrigerant and moves to the other end side region (R2) side. Then, the valve element (19) on the one end side region (R1) side approaches the valve opening (16A), while the valve element (19) on the other end side region (R2) side is separated from the valve opening (16B). The contact shaft (37) is in a stretched state between each valve element (19) and each diaphragm (34).

  In this state, when the diaphragm (34) is deformed in accordance with the refrigerant pressure in the intermediate region (R3), the position of each valve element (19) with respect to the valve port (16A, 16B) is changed along with the deformation. The opening varies within a predetermined range. Here, since the valve element (19) of the other end side region (R2) located downstream is separated from the valve opening (16B) and the valve opening degree is large, the valve opening degree changes within a predetermined range. Even so, the effect on the flow rate and refrigerant pressure is small. On the other hand, the valve element (19) in the one end side region (R1) located upstream approaches the valve opening (16A) and the valve opening is reduced, so that the valve opening changes within a predetermined range. The effect on the flow rate and refrigerant pressure is great. When the refrigerant pressure in the intermediate region (R3) becomes relatively large, the valve body (19) approaches the valve port (16A), and the flow rate of the refrigerant passing through the valve port (16A) in the one end side region (R1) is increased. The refrigerant pressure in the intermediate region (R3) is reduced by being throttled. On the contrary, when the refrigerant pressure in the intermediate region (R3) becomes relatively small, the valve opening degree of the valve port (16A) on the one end side region (R1) side becomes large, and the valve in the one end side region (R1) becomes larger. The flow rate of the refrigerant passing through the port (16A) increases, and the refrigerant pressure in the intermediate region (R3) increases. As a result, the refrigerant pressure downstream of the valve port (16A) can be made constant. Further, when the heat pump circuit (90) is switched between cooling and heating, the direction in which the refrigerant flows is reversed, and the valve opening degree of the valve port (16B) on the other end side region (R2) side located upstream as in the above case. However, it changes according to the refrigerant | coolant pressure of an intermediate | middle area | region (R3), and can make the refrigerant | coolant pressure downstream from the valve port (16B) constant.

  Further, according to the bidirectional constant pressure expansion valve (10) of claim 2, when the refrigerant flows in the order of the one end side region (R1), the intermediate region (R3), and the other end side region (R2), it is positioned upstream. The valve body (19) in the one end side region (R1) is pushed by the fluid pressure of the refrigerant and approaches the valve port (16A), and a contact shaft (between the valve body (19) and the diaphragm (34)) 37) is in a stretched state. On the other hand, the valve element (19) in the other end side region (R2) located on the downstream side is pushed away from the valve port (16B) and the contact shaft (37) by the fluid pressure of the refrigerant, and the valve port (16B) ) The refrigerant flows relatively freely. Thereby, similarly to the bidirectional constant pressure expansion valve (10) of claim 1, the valve opening degree of the upstream side valve ports (16A, 16B) changes according to the refrigerant pressure in the intermediate region (R3), and the downstream side The refrigerant pressure can be made constant.

  Thus, according to the bidirectional constant pressure expansion valve (10) of claims 1 and 2, the downstream refrigerant pressure can be made constant. Since the diaphragm (34) is used instead of the bellows (4) used as a pressure-sensitive member in the conventional bidirectional constant pressure expansion valve, the cost can be reduced as compared with the conventional one. Moreover, according to the structure of Claim 2, since the movable pressure sensing body 30 is being fixed to the body (10B), performance is stabilized and it is excellent also in durability. Furthermore, the bidirectional constant pressure expansion valve (10) according to claims 1 and 2 has a diaphragm (34) for changing the valve opening degree of each valve port (16A, 16B) for each valve port (16A, 16B). Since it is provided separately, the characteristics of the valve opening degree with respect to the refrigerant pressure of the valve port (16B) on the indoor heat exchanger (92A) side and the refrigerant pressure of the valve port (16A) on the outdoor heat exchanger (91A) side The characteristics of the valve opening can be set to characteristics suitable for each.

  Specifically, as in the bi-directional constant pressure expansion valve (10) of claim 3, the elastic coefficients of the pair of diaphragms (34) are made different so that the refrigerant pressure and the refrigerant flow are different during cooling operation and heating operation. It is possible to obtain an optimal valve lift characteristic capable of controlling the refrigerant pressure and flow rate.

  Further, as in the bi-directional constant pressure expansion valve (10) of claim 4, a pressure sensitive auxiliary spring (32) is provided separately for each diaphragm (34), and the diaphragm (34) and the pressure sensitive auxiliary spring (32) are provided. The valve body (19) may be operated by a resilient force combined with the above. In this case, the optimal valve lift characteristic can be obtained by making the elastic coefficients of the pair of pressure-sensitive auxiliary springs (32) different from each other as in the fifth aspect of the invention.

  Further, as in the bi-directional constant pressure expansion valve (10) of claim 6, the opening area of the gap between one valve port (16A) and the contact shaft (37) is set in contact with the other valve port (16B). You may make it wider than the opening area of the clearance gap with a shaft (37). As a result, the refrigerant pressure on the downstream side during either one of the heating and cooling operations becomes larger than the refrigerant pressure on the downstream side during the other operation, and the optimum temperature and pressure are obtained during the cooling operation and the heating operation, respectively. The controlled refrigerant can be supplied to the outdoor and indoor heat exchangers (91A, 92A).

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
A body 10 </ b> B of the bidirectional constant pressure expansion valve 10 of the present embodiment shown in FIG. 1 includes a pair of opposing walls 13 and 13 inside a pipe member 12. For example, the pipe member 12 has a circular cross section and extends straight, and is reduced in a tapered shape at positions near both ends, with the diameters at both ends being smaller than the intermediate portion.

  The pair of opposing walls 13 and 13 are separate parts from the pipe member 12. A cylindrical wall 13 </ b> A protrudes from the outer edge portion of one opposing wall 13 (upper opposing wall 13 in FIG. 1) toward the other opposing wall 13. The other opposing wall 13 is formed with a fitting portion 13B having a reduced diameter at one end, the fitting portion 13B is fitted into the cylindrical wall 13A, and the opposing walls 13 and 13 are cored with each other. It has been started. Further, the tip end surface of the cylindrical wall 13A is abutted against the step portion of the other opposing wall 13, and is positioned so that the interval between the opposing walls 13 and 13 becomes a constant size.

  A locking groove 13 </ b> C is formed on the outer peripheral surface of each facing wall 13 over the entire circumference. Correspondingly, a pair of protrusions 12T and 12T are formed by bending a part of the pipe member 12 inward in the entire circumferential direction at two axial positions in the intermediate portion of the pipe member 12. These protrusions 12T are engaged in the locking grooves 13C of the opposing walls 13. The opposing walls 13 and 13 are positioned and fixed in the pipe member 12 and the gap between the outer peripheral surface of the opposing walls 13 and 13 and the inner peripheral surface of the pipe member 12 is closed. Thereby, the flow path 11 in the pipe member 12 is divided into one end side area | region R1, intermediate | middle area | region R3, and other end side area | region R2 by a pair of opposing walls 13 and 13. FIG.

  Valve ports 16 </ b> A and 16 </ b> B are formed at the center of the opposing walls 13 and 13. These valve ports 16A and 16B have both circular openings, and are arranged coaxially with each other. The refrigerant flows through the valve ports 16A and 16B between the one end side region R1 and the intermediate region R3 and between the intermediate region R3 and the other end side region R2. A tapered valve seat 16Z is formed at the opening edge on the one end side region R1 side of the one valve port 16A and the opening edge on the other end side region R2 side of the other valve port 16B.

  A movable pressure sensitive body 30 is accommodated in the intermediate region R3. As shown in FIG. 2, the movable pressure-sensitive body 30 includes a cylindrical intermediate cylinder 31 that extends between the pair of opposing walls 13 and 13 and is disposed concentrically with the valve ports 16A and 16B. Yes. A flange portion 31 </ b> F protrudes laterally from both end opening edges of the intermediate cylinder 31. A diaphragm fixing plate 35 is provided between both end portions of the intermediate cylindrical body 31 and each facing wall 13. The diaphragm fixing plate 35 has a flat cylindrical shape with one end, and a flange portion 35F projects laterally from one end opening edge of the flat cylindrical wall portion 35D. The flange portion 35F has the same shape as the flange portion 31F of the intermediate cylinder 31. The outer edge portion of the diaphragm 34 is sandwiched between the flange portions 31F and 35F, and both the flange portions 31F and 35F and the diaphragm 34 are welded. .

  In each of the opposing walls 13, 13, fitting recesses 13 </ b> D are formed to be depressed corresponding to both ends of the movable pressure-sensitive body 30. Further, the distance between the back surface of one fitting recess 13D and the back surface of the other fitting recess 13D is larger than the distance between the end surfaces of the diaphragm fixing plates 35, 35 in the movable pressure sensitive body 30. . And the edge part of both diaphragm fixing plates 35 and 35 is hold | maintained in the state fitted in fitting recessed part 13D, 13D, and the movable pressure sensing body 30 moves directly between the opposing walls 13 and 13. FIG. Further, a coolant passage groove 16C is formed in the inner surface of the fitting recess 13D. One end of the refrigerant passage groove 16C communicates with the valve port 16A (16B), and the other end of the refrigerant passage groove 16C passes through the side of the fitting recess 13D and opens to the intermediate region R3. Thereby, regardless of the position of the movable pressure sensing body 30, the intermediate region R3 is always in communication with the valve ports 16A and 16B.

  A shaft insertion hole 35 </ b> C is formed through the center portion of the bottom wall 35 </ b> B of the diaphragm fixing plate 35. Further, a cylindrical excessive deformation preventing portion 35 </ b> T protrudes from the opening edge of the diaphragm fixing plate 35 toward the diaphragm 34. And the front end surface of the excessive deformation | transformation prevention part 35T is faced | matched with the center part of the diaphragm 34, and the excessive deformation | transformation to the diaphragm stationary platen 35 side in the diaphragm 34 is prevented.

  A contact shaft 37 stands upright from the center of the outer surface of the diaphragm 34 surrounded by the excessive deformation prevention portion 35T, and the contact shaft 37 is inserted into the excessive deformation prevention portion 35T and the valve ports 16A and 16B. Then, it is abutted against a spherical valve body 19 described later.

  A plurality of refrigerant passage holes 36 are formed through the portion of the flat cylindrical wall portion 35D of the diaphragm fixing plate 35 that is always located outside the fitting recess 13D. Then, the refrigerant enters and exits the diaphragm fixing plate 35 through the refrigerant passage hole 36, and the refrigerant pressure is applied to the outer surface of the diaphragm 34.

  The intermediate cylinder 31 is configured to keep the inside at a constant pressure such as vacuum or atmospheric pressure. A spring locking wall 31 </ b> A is formed to project from the entire inner peripheral surface of the intermediate cylindrical body 31 in the axial direction. An inner support plate 33 is assigned to the inner surface of the diaphragm 34. A pair of pressure-sensitive auxiliary springs 32 are provided in a tensioned state between the spring locking wall 31A and both diaphragms 34, 34 inside the intermediate cylinder 31. Here, in this embodiment, the elastic coefficients are different between the two pressure-sensitive auxiliary springs 32 and 32. Specifically, the elastic coefficient of the pressure sensitive auxiliary spring 32 near the one end side region R1 is larger than the elastic coefficient of the pressure sensitive auxiliary spring 32 on the opposite side.

  The center portion of the inner support plate 33 protrudes toward the diaphragm 34, and only the tip surface of the protruding portion is in contact with the diaphragm 34. Further, the outer edge portion of the inner support board 33 faces a step portion 31D formed on the inner surface of the intermediate cylinder 31 with a gap. And when the diaphragm 34 bends to the back | inner side of the intermediate cylinder 31 to the predetermined amount, the inner support board 33 and the level | step-difference part 31D contact | abut, and the excessive deformation | transformation of the diaphragm 34 is prevented.

  As shown in FIG. 1, each of the opposing walls 13, 13 is formed with an end cylindrical wall 14 protruding on the opposite surface to the inside of the intermediate region R <b> 3. A female screw portion 14 </ b> A is formed in a portion near the tip of the inner surface of the end cylindrical wall 14, and a nut 15 is screwed therein. A through hole 15A is formed at the center of the nut 15, and the internal space of the end cylindrical wall 14 communicates with the one end side region R1 or the other end side region R2.

  Between each nut 15 and each valve seat 16Z, a valve body urging spring 17, a pressing member 18, and a spherical valve body 19 are accommodated in this order from the nut 15 side. The pressing member 18 has a cylindrical shape as a whole, and has a structure in which one end is enlarged in a stepped shape, and a ball receiving recess 18A is recessed in the end surface on the large diameter side. One end of the valve body biasing spring 17 is abutted against the opening edge of the through-hole 15A in the nut 15 and is centered by an annular protrusion (not shown) protruding from the opening edge. The other end of the spring 17 is fitted into the small diameter portion of the pressing member 18. The valve body 19 abuts on the conical inner surface of the ball receiving recess 18A of the pressing member 18, and the valve body 19 is biased toward the valve ports 16A and 16B by the elastic force of the valve body biasing spring 17.

  The configuration of the bidirectional constant pressure expansion valve 10 according to the present embodiment has been described above. Next, the operation when the bidirectional constant pressure expansion valve 10 is assembled to the heat pump circuit 90 shown in FIG. 4 will be described below. . The heat pump circuit 90 is provided in a room air conditioner for general households, for example. The heat pump circuit 90 includes an outdoor heat exchanger 91A and an indoor heat exchanger 92A. The outdoor heat exchanger 91A is incorporated in the outdoor unit 91 of the room air conditioner, while the indoor heat exchanger 92A is installed in the indoor unit 92. It has been incorporated. The outdoor heat exchanger 91A and the indoor heat exchanger 92A are connected by a pair of pipes 96A and 96B to form a refrigerant circulation path 96 including the outdoor heat exchanger 91A and the indoor heat exchanger 92A. Then, the refrigerant passes through the outdoor heat exchanger 91A and the indoor heat exchanger 92A and circulates in the refrigerant circulation path 96. Then, when the refrigerant passes through the outdoor heat exchanger 91A, heat exchange is performed between the refrigerant and the outside air, and when the refrigerant passes through the indoor heat exchanger 92A, heat exchange is performed between the refrigerant and the indoor air. Is done.

  The bidirectional constant pressure expansion valve 10 of the present embodiment is assembled in the outdoor unit 91 and connected in the middle of one conduit 96A that communicates between the outdoor heat exchanger 91A and the indoor heat exchanger 92A. . And one end side area | region R1 shown to the upper side of FIG. 1 among body 10B is always connected to outdoor heat exchanger 91A, while the other end side area | region R2 shown to the lower side of FIG. 1 is always connected to indoor heat exchanger 92A. It is in a state of communication. On the outdoor unit 91 side, a compressor 94 is connected to the other pipe 96B through a four-way valve 93. When the heat pump circuit 90 is switched between the cooling operation and the heating operation, the four-way valve 93 is activated, and the direction of the refrigerant flowing through the refrigerant circulation path 96 is reversed.

  Now, during the cooling operation of the heat pump circuit 90, in one of the pipes 96A, the refrigerant flows from the indoor heat exchanger 92A to the outdoor heat exchanger 91A. At this time, in the bidirectional constant pressure expansion valve 10, as shown in FIG. As indicated by the arrows, the refrigerant flows in the order of one end side region R1, one valve port 16A, intermediate region R3, the other valve port 16B, and the other end side region R2.

  Then, the movable pressure sensitive body 30 in the intermediate region R3 is pushed by the refrigerant and moves to the other end region R2 side (in this case, the lower side in FIG. 2). Then, the valve body 19 on the one end side region R1 side approaches the valve port 16A, while the valve body 19 on the other end side region R2 side is separated from the valve port 16B, and between each valve body 19 and each diaphragm 34. As a result, the abutting shaft 37 is stretched. In this state, when the diaphragm 34 is deformed according to the refrigerant pressure in the intermediate region R3, the position of each valve body 19 with respect to the valve ports 16A and 16B is changed and the valve opening is changed within a predetermined range. .

  Here, since the valve element 19 in the other end side region R2 located downstream is separated from the valve port 16B and has a large valve opening, the flow rate and the refrigerant even if the valve opening changes within a predetermined range. The effect on pressure is small. On the other hand, since the valve element 19 of the one end side region R1 located upstream approaches the valve port 16A and the valve opening degree is small, the flow rate and refrigerant when the valve opening degree changes within a predetermined range. The effect on pressure is significant. When the refrigerant pressure in the intermediate region R3 becomes relatively large, the valve body 19 approaches the valve port 16A, the flow rate of the refrigerant passing through the valve port 16A in the one end side region R1 is reduced, and the refrigerant in the intermediate region R3 The pressure drops. On the contrary, when the refrigerant pressure in the intermediate region R3 becomes relatively small, the valve opening degree of the valve port 16A on the one end side region R1 side increases, and the flow rate of the refrigerant passing through the valve port 16A on the one end side region R1. Increases, and the refrigerant pressure in the intermediate region R3 increases. As a result, the refrigerant pressure downstream of the valve port 16A can be made constant.

  Further, when the heat pump circuit 90 is switched between cooling and heating, the direction in which the refrigerant flows is reversed as shown in the changes in FIG. 2 to FIG. 3, and the valve port on the other end side region R2 side located upstream as described above. The valve opening degree of 16B changes according to the refrigerant | coolant pressure of intermediate area | region R3, and the refrigerant | coolant pressure downstream from the valve port 16B can be made constant. Here, in the present embodiment, the elastic coefficient of the pressure-sensitive auxiliary spring 32 near the one end side region R1 located upstream during the cooling operation is larger than the elastic coefficient of the pressure-sensitive auxiliary spring 32 on the opposite side. The refrigerant pressure on the downstream side of the bidirectional constant pressure expansion valve 10 is higher in the cooling operation in which the refrigerant pressure on the downstream side is adjusted by the one end region R1 side than in the heating operation.

  Thus, according to the bidirectional constant pressure expansion valve 10 of the present embodiment, the downstream refrigerant pressure can be made constant. In addition, since the diaphragm 34 is used instead of the bellows used as the pressure-sensitive member in the conventional bidirectional constant pressure expansion valve, the cost can be reduced as compared with the conventional one. Moreover, since the diaphragm 34 for changing the valve opening degree of each valve port 16A, 16B is provided separately for each valve port 16A, 16B, the valve opening with respect to the refrigerant pressure of the valve port 16B on the indoor heat exchanger 92A side is provided. The characteristic of the degree and the characteristic of the valve opening with respect to the refrigerant pressure of the valve port 16A on the outdoor heat exchanger 91A side can be set to appropriate characteristics. Specifically, in the present embodiment, an optimal valve that can control the refrigerant pressure and flow rate in the cooling operation and the heating operation in which the refrigerant coefficient and the refrigerant flow rate are different from each other by changing the elastic coefficients of the pair of diaphragms 34. The lift characteristics can be obtained.

[Second Embodiment]
The bidirectional constant pressure expansion valve 10 of the present embodiment is shown in FIG. 5, and the movable pressure sensing body 30 is fixed between the opposing walls 13 and 13, and the refrigerant passage hole 36 is provided in the excessive deformation preventing portion 35 </ b> T. Is different in that it is formed through.

  According to the bidirectional constant pressure expansion valve 10 of the present embodiment, when the refrigerant flows in the order of the one end side region R1, the intermediate region R3, and the other end side region R2, the valve element 19 on the one end side region R1 side located on the upstream side. Is close to the valve port 16A, while the valve body 19 on the other end side region R2 side located on the downstream side is separated from the valve port 16B, and the contact shaft 37 is stretched between each valve body 19 and the diaphragm 34. become. Then, similarly to the bidirectional constant pressure expansion valve 10 of the first embodiment, the valve openings of the upstream valve ports 16A and 16B change according to the refrigerant pressure in the intermediate region R3, and from the valve ports 16A and 16B. The downstream refrigerant pressure can be made constant.

  The bi-directional constant pressure expansion valve 10 of the present embodiment can achieve the same effects as the bi-directional constant pressure expansion valve 10 of the first embodiment, and the performance is stable and durable because the movable pressure sensing body 30 is fixed. Excellent in properties.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) Although the body 10B provided in the bidirectional constant pressure expansion valve 10 of the first and second embodiments is configured by assembling the pipe member 12 and the opposing wall 13, the opposing wall 13 is connected to the pipe member. What is integrally formed with 12 is also included in the technical scope of the present invention.

  (2) In the first embodiment, the elastic coefficient of the pair of pressure-sensitive auxiliary springs 32, 32 is made different so that the refrigerant pressure on the downstream side is different between the heating operation and the cooling operation. The elastic coefficients of the pair of diaphragms 34 and 34 may be different, or the elastic coefficient obtained by combining both the diaphragm 34 and the pressure-sensitive auxiliary spring 32 is set between the one end side and the other end side of the bidirectional constant pressure expansion valve 10. It may be different between.

  (3) Further, the opening area of the gap between the one valve port 16A and the contact shaft 37 located on the downstream side during the heating operation is different from the opening area of the gap between the other valve port 16B and the contact shaft 37. Thus, a difference may be provided in the refrigerant pressure on the downstream side between the heating operation and the cooling operation.

  (4) Furthermore, the configuration of both ends of the bidirectional constant pressure expansion valve described above may be the same, and the downstream refrigerant pressure may be the same during heating operation and cooling operation.

Side sectional view of the bidirectional constant pressure expansion valve according to the first embodiment of the present invention. Side sectional view of the bidirectional constant pressure expansion valve Side sectional view of the bidirectional constant pressure expansion valve Conceptual diagram of heat pump circuit Side sectional view of a bidirectional constant pressure expansion valve according to a second embodiment Side sectional view of a conventional bidirectional constant pressure expansion valve

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bidirectional constant pressure expansion valve 10B Body 11 Flow path 12 Pipe member 13 Opposite wall 16A, 16B Each valve port 17 Valve body urging spring 19 Valve body 31 Intermediate cylinder 31A Locking wall 32 Pressure sensitive auxiliary spring 34 Diaphragm 37 Contact Shaft 90 Heat pump circuit 91A Outdoor heat exchanger 92A Indoor heat exchanger R1 One end side region R2 Other end side region R3 Middle region

Claims (6)

Both are connected between the indoor heat exchanger (92A) and the outdoor heat exchanger (91A) of the heat pump circuit (90) so that the refrigerant flows in both directions, and the downstream refrigerant pressure can be made constant. In the constant pressure expansion valve (10),
A body (10B) having a flow path (11) for the refrigerant therein;
A pair of opposing walls (13) provided in the body (10B) and dividing the flow path (11) into one end side region (R1), an intermediate region (R3), and the other end side region (R2); ,
A pair of valve ports (16A, 16B) that are formed through the pair of opposing walls (13) and arranged substantially coaxially;
A pair of valve bodies (19) disposed in the one end side region (R1) and the other end side region (R2), respectively, for opening and closing the valve ports (16A, 16B);
A pair of valve body biasing springs (17) for biasing the valve bodies (19) toward the valve ports (16A, 16B);
An intermediate cylinder (31) accommodated in the intermediate region (R3) and extending in the opposing direction of the pair of opposing walls (13) and capable of linear movement between the pair of opposing walls (13);
A pair of diaphragms (34) that close both ends of the intermediate cylinder (31) and deform in accordance with the internal pressure of the intermediate region (R3);
Each of the pair of valve ports (16A, 16B) is loosely fitted to be stretched between the valve body (19) and the diaphragm (34), and the diaphragm (34) is subjected to the deformation amount according to the deformation amount of the diaphragm (34). A bidirectional constant pressure expansion valve (10) comprising a pair of contact shafts (37) for moving the valve body (19) to change the valve opening degree of the valve ports (16A, 16B) . Both are connected between the indoor heat exchanger (92A) and the outdoor heat exchanger (91A) of the heat pump circuit (90) so that the refrigerant flows in both directions and the refrigerant pressure on the downstream side can be made constant. In the constant pressure expansion valve (10),
A body (10B) having a flow path (11) for the refrigerant therein;
A pair of opposing walls (13) provided in the body (10B) and dividing the flow path (11) into one end side region (R1), an intermediate region (R3), and the other end side region (R2); ,
A pair of valve ports (16A, 16B) that are formed through the pair of opposing walls (13) and arranged substantially coaxially;
A pair of valve bodies (19) disposed in the one end side region (R1) and the other end side region (R2), respectively, for opening and closing the valve ports (16A, 16B);
A pair of valve body biasing springs (17) for biasing the valve bodies (19) toward the valve ports (16A, 16B);
An intermediate cylinder (31) extending in the opposing direction of the pair of opposing walls (13) and fixed to the body (10B);
A pair of diaphragms (34) that close both ends of the intermediate cylinder (31) and deform in accordance with the internal pressure of the intermediate region (R3);
Each of the pair of valve ports (16A, 16B) is loosely fitted to be stretched between the valve body (19) and the diaphragm (34), and the diaphragm (34) is subjected to the deformation amount according to the deformation amount of the diaphragm (34). A bidirectional constant pressure expansion valve (10) comprising a pair of contact shafts (37) for moving the valve body (19) to change the valve opening degree of the valve ports (16A, 16B) .   The bidirectional constant pressure expansion valve (10) according to claim 1 or 2, wherein the elastic coefficients of the pair of diaphragms (34) are different. A spring locking wall (31A) is formed so as to protrude from the axially intermediate portion of the inner surface of the intermediate cylinder (31),
A pair of pressure-sensitive auxiliary springs (32) are provided in a stretched state between the spring locking wall (31A) and both the diaphragms (34). Bidirectional constant pressure expansion valve (10) according to   The bidirectional constant-pressure expansion valve (10) according to claim 4, wherein the pair of pressure-sensitive auxiliary springs (32) have different elastic coefficients. The opening area of the gap between the one valve port (16A) and the contact shaft (37) is made larger than the opening area of the gap between the other valve port (16B) and the contact shaft (37). The bidirectional constant pressure expansion valve (10) according to any one of claims 1 to 5, characterized by:

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