JP2007225209A - Bidirectional constant pressure expansion valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bidirectional constant pressure expansion valve capable of surely making a refrigerant pressure on a downstream side constant in comparison with a conventional one. <P>SOLUTION: In this bidirectional constant pressure expansion valve 10, centering of a movable opposed disc 44 is performed while guided by a guide projecting portion 44B of the movable opposed disc 44 and a guide recessed portion 13U of an opposed wall 13, even when bellows 41 is moved to any of one end side and the other end side according to the flow of a refrigerant, and the bellows 41, a contact shaft 37 and a valve element 19 are coaxially disposed. Thus characteristics of the valve is stabilized as a contact position of the contact shaft 37 and the valve element 19 is stabilized, and the refrigerant pressure at the downstream side can be surely made constant in comparison with the conventional one. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 body of the conventional bidirectional constant pressure expansion valve shown in FIG. 6 is formed by closing both ends of the cylindrical case 2 with opposing walls 1 and 1. Each opposing wall 1 is provided with a ball valve mechanism 4, and a bellows 5 is accommodated between the opposing walls 1, 1. Further, a pair of pressing shafts 7 and 7 extend from the movable opposing plates 5A and 5A which close both ends of the bellows 5 toward the ball valve mechanisms 4 and 4, respectively. The bellows 5 linearly moves in the cylindrical case 2 in accordance with the direction in which the refrigerant flows, and expands and contracts in accordance with the refrigerant pressure in a state in which one end is in contact with the opposing wall 1 on the downstream side. Thereby, the valve opening degree of the ball valve mechanism 4 on the upstream side is adjusted, and the refrigerant pressure on the downstream side becomes constant (for example, see Patent Document 1).
Japanese Patent No. 4418271 (paragraph [0013], FIG. 1)

  However, each time the bellows 5 linearly moves between the opposing walls 1 and 1 in the above-described conventional bidirectional constant pressure expansion valve, the bellows 5 is shifted in a direction orthogonal to the linear motion direction, and the characteristics of the valve change. In some cases, the refrigerant pressure on the downstream side was not constant.

  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 capable of making the downstream refrigerant pressure constant more reliably than before.

  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 ports (16A, 16B), and a pair of opposed walls (13) that are accommodated in the intermediate region (R3) Fixed to one of a bellows (41) extending in the direction, a pair of movable facing plates (44) in which both ends of the bellows (41) are sealed, and a valve body (19) and a movable facing plate (44) And is loosely fitted to the pair of valve ports (16A, 16B), and is stretched between the valve body (19) and the movable counter board (44), and the valve body according to the deformation amount of the bellows (41). A pair of abutting shafts (37) that move (19) to change the valve opening degree of the valve ports (16A, 16B), and a guide that protrudes from the movable facing plate (44) toward the facing wall (13) The protrusion (44B) and the guide protrusion (44B) are fitted into the end surface of the opposing wall (13) and the bellows (4 ), Having characterized in that the contact shaft (37) and the valve body (19) has a guide recess (13U) to center the movable counter plate (44) so as to be aligned coaxially.

  The invention of claim 2 is characterized in that, in the bidirectional constant pressure expansion valve (10) of claim 1, the guide recess (13U) and the guide projection (44B) are always fitted.

  According to a third aspect of the present invention, in the bidirectional constant pressure expansion valve (10) according to the second aspect, a sliding ring (44E) is provided on one peripheral surface of the guide recess (13U) or the guide projection (44B). It has features.

  The invention of claim 4 is characterized in that, in the bidirectional constant pressure expansion valve (10) of claim 3, the sliding ring (44E) is formed of a slidable resin.

  The bidirectional constant pressure expansion valve (10) according to the invention of claim 5 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, a bellows (41) housed in the intermediate region (R3) and extending in the opposing direction of the pair of opposing walls (13), and a bellows (41) A pair of valve openings (16A, 16B) fixed to either one of the pair of movable counterboards (44) with both ends sealed and the valve element (19) and the movable counterboard (44). ), And is in a stretched state between the valve body (19) and the movable counter plate (44), and moves the valve body (19) in accordance with the deformation amount of the bellows (41), thereby opening the valve port (16A). , 16B), a pair of abutting shafts (37) for changing the valve opening degree, a conical intrusion portion (44F) formed in a movable opposing plate (44) and having a reduced diameter in a tapered shape, and an opposing wall ( 13), the inner diameter is reduced to a taper shape, and the conical ridge (44F) is fitted into the bellows (41) and the contact shuff. (37) and a conical recess (13T) for centering the movable counter plate (44) so that the valve bodies (19) are arranged coaxially, and a pair of movable counter plates (44) are connected, It is characterized in that a buckling prevention mechanism (45) that allows linear movement in a state where the movable opposing boards (44) are held coaxially is provided.

  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).

[Invention of Claim 1]
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 it flows in the order of the other end side region (R2), the bellows (41) is pushed by the refrigerant and moves to the other end side, and the movable opposing plate (44) on the other end side contacts the opposing wall (13). While being positioned in the axial direction, the movable facing plate (44) on one end side is separated from the facing wall (13). And each contact shaft (37) will be in the tension state between each valve body (19) and each movable opposing board (44), and the valve body (19) of the other end side area | region (R2) will become a valve. The valve port is held at a position away from the port (16B), and the valve body (19) in the one end side region (R1) is close to the valve port (16A), depending on the refrigerant pressure in the intermediate region (R3). Contact (16A). Thereby, the refrigerant | coolant pressure downstream from the valve port (16A) of a one end side area | region (R1) can be made constant. Similarly, when the cooling / heating is switched and the flow direction of the refrigerant is reversed, similarly, the valve opening degree of the valve port (16B) on the other end side region (R2) side located upstream is the refrigerant pressure in the intermediate region (R3). The refrigerant pressure on the downstream side of the valve port (16B) can be made constant. Here, in the present invention, even if the bellows (41) moves to one end side or the other end side in accordance with the flow of the refrigerant, the guide protrusion (44B) and the opposing wall (13) of the movable facing plate (44). ) With the guide recess (13U), the bellows (41), the contact shaft (37) and the valve body (19) are centered so as to be aligned coaxially. As a result, the characteristics of the valve are stabilized, and the downstream refrigerant pressure can be made constant more reliably than in the past.

[Inventions of Claims 2, 3 and 4]
According to the configuration of the second aspect, regardless of the linear movement position of the bellows (41), the guide recess (13U) and the guide protrusion (44B) are always fitted, and the movable counterboard (44) is always centered. As a result, the characteristics of the valve are further stabilized. In this case, as in the configuration of claim 3, by providing the guide recess (13U) or the guide projection (44B) with the sliding ring (44E), the sliding resistance can be suppressed and the characteristics of the valve can be further stabilized. Can do. The sliding ring (44E) is preferably made of a slidable resin (invention of claim 4).

[Invention of claim 5]
According to the bidirectional constant pressure expansion valve (10) of claim 5, the bellows (41) moves between the opposing walls (13), and the movable opposing disk (44) and the opposing wall are arranged on one end side of the bellows (41). When it abuts on (13), the movable counter board (44) is centered by the fitting of the conical intrusion part (44F) and the conical concave part (13T). Here, since the buckling of the bellows (41) is regulated by the buckling prevention mechanism (45), the entire bellows (41) and the abutting shaft are arranged by the centering on one end side of the bellows (41). (37) and the valve body (19) are centered. As a result, the characteristics of the valve are stabilized, and the downstream refrigerant pressure can be made constant more reliably than before.

[Invention of claim 6]
As in the bi-directional constant pressure expansion valve (10) of claim 6, the opening area of the gap between the one valve port (16A) and the contact shaft (37) located on the downstream side during either heating or cooling operation, The opening area of the gap between the other valve port (16B) and the contact shaft (37) may be larger. As a result, the refrigerant flow rate controlled and flowed by the bidirectional constant pressure expansion valve (10) during either one of the heating and cooling operations is larger than the refrigerant flow rate controlled and flowed during the other operation, and is relatively large. It is possible to appropriately cope with the heating operation requiring a flow rate (large capacity).

[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.

  Both opposing walls 13, 13 have a circular cross section that can be fitted into 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. ing. Then, the protrusions 12T are engaged in the locking grooves 13C of the opposing walls 13 and 13 so that the opposing walls 13 and 13 are positioned and fixed in the pipe member 12, and the outer peripheral surfaces of the opposing walls 13 and 13 And the inner peripheral surface of the pipe member 12 are closed. Thereby, the flow path 11 in the pipe member 12 is connected to the one end side region R1 on the one end side, the other end side region R2 on the other end side, the one end side region R1, and the other end side region R2 by the pair of opposing walls 13 and 13. And an intermediate region R3 in the middle.

  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 part 40 is accommodated in the intermediate region R3. As shown in FIG. 2, the movable pressure sensing unit 40 is formed by sealing both ends of a bellows 41 extending between a pair of opposed walls 13, 13 with a pair of movable opposed plates 44, 44. The inside of the bellows 41 is maintained at a constant pressure such as vacuum or atmospheric pressure.

  Each movable counter board 44 includes a disk-like flange portion 44F, and has a circular protrusion 44A at the center of the inner surface of the flange portion 44F facing the inside of the bellows 41. An extension cylinder member 43 is fixed to the circular protrusion 44A. The extension cylinder member 43 has a cylindrical shape with one end and is fixed (by press-fitting or welding) with its open end fitted into the circular protrusion 44A.

  A pressure-sensitive auxiliary spring 42 is inserted outside the extension cylinder members 43, 43, and the pressure-sensitive auxiliary spring 42 is stretched between the movable opposing plates 44, 44. A through hole 43 </ b> A is formed through the bottom wall 43 </ b> B of both the extended cylinder members 43. A guide pin 48 having a head portion 48 </ b> H at one end is inserted into the through-holes 43 </ b> A and 43 </ b> A from the inside of the one extension cylinder member 43 and enters the inside of the other extension cylinder member 43. Further, a stopper ring 49 is mounted in a ring groove 48M provided at the tip of the guide pin 48 in the other extension cylinder member 43, and the guide pin 48 is prevented from coming off in the through holes 43A and 43A by the head portion 48H and the stopper ring 49. Has been. Further, the extension cylinder members 43, 43, the guide pin 48, and the stopper ring 49 constitute a buckling prevention mechanism 45. And by this buckling prevention mechanism 45 and the pressure-sensitive auxiliary spring 42, the bottom walls 43B, 43B of both the extended cylindrical members 43, 43 are always opposed to each other through a gap, and the bellows 41 is made to narrow the gap. Can be compressed and deformed.

  A guide recess 13U is formed in a recessed manner on the end surface of the intermediate region R3 in each of the opposing walls 13. The guide recess 13U has a circular inner diameter that is concentric with the valve port 16A (16B) and extends in a uniform diameter in the axial direction of the bidirectional constant-pressure expansion valve 10. 16A (16B) is opened. On the other hand, a cylindrical guide protrusion 44B is formed to protrude from the center of the outer surface of the flange portion 44F of the movable counter board 44. And this guide protrusion 44B is always fitted in the guide recessed part 13U in the state which can be moved linearly.

  A refrigerant communication hole 16D is formed in the guide protrusion 44B. The refrigerant communication hole 16D extends from the distal end surface of the guide projection 44B to the boundary portion between the guide projection 44B and the flange portion 44F, and is bent at a right angle at the boundary portion, to the distal end surface and the side surface of the guide projection 44B. It is open. A refrigerant passage groove 16C is formed at the opening edge of the guide recess 13U at a position facing the side opening of the refrigerant communication hole 16D. One end portion of the refrigerant passage groove 16 </ b> C extends to the outside from the outer edge portion of the movable facing plate 44. As a result, regardless of the position of the movable opposing board 44, the intermediate region R3 is always in communication with the valve ports 16A and 16B.

  The guide protrusion 44B has a contact shaft 37 loosely fitted inside the refrigerant communication hole 16D, and one end of the contact shaft 37 is fixed to the flange portion 44F. The other end of the abutting shaft 37 protrudes from the distal end surface of the guide protrusion 44B, is inserted into the valve ports 16A and 16B, and is abutted against a spherical valve body 19 described later.

  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. 3 will be described. 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 bellows 41 is pushed by the refrigerant and moves to the other end side, and the movable counter plate 44 on the other end side of the bellows 41 contacts the counter wall 13 and is positioned in the axial direction. 44 separates from the facing wall 13. The contact shaft 37 is stretched between each valve body 19 and each movable counter plate 44, so that the valve body 19 in the other end region R2 is held at a position away from the valve port 16B. At the position where the valve element 19 of the one end side region R1 approaches the valve port 16A, the valve body 16 contacts and separates from the valve port 16A according to the refrigerant pressure in the intermediate region R3. Thereby, the refrigerant | coolant pressure downstream from the valve port 16A of one end side area | region R1 can be made constant. Similarly, when the cooling / heating is switched and the refrigerant flow direction is reversed, the valve opening degree of the valve port 16B of the other end side region R2 located upstream changes according to the refrigerant pressure of the intermediate region R3, The refrigerant pressure downstream of the valve port 16B can be made constant.

  Here, in the present embodiment, even if the bellows 41 moves to one end side or the other end side according to the flow of the refrigerant, the guide projection 44B of the movable facing plate 44 and the guide recess 13U of the facing wall 13 The movable opposing board 44 is centered by the guide, and the bellows 41, the contact shaft 37, and the valve body 19 are arranged coaxially. Thereby, the contact position of the contact shaft 37 and the valve body 19 is stabilized. In addition, regardless of the linear movement position of the bellows 41, the guide protrusions 44B on the movable opposing plates 44, 44 at both ends of the bellows 41 are always fitted in the guide recesses 13U, so the contact shaft 37 and the valve body The stability of the contact position with 19 increases. Further, the buckling of the bellows 41 can be reliably prevented by the cooperation of the guide mechanism by the guide protrusion 44B and the guide recess 13U and the buckling prevention mechanism 45. Accordingly, in the bidirectional constant pressure expansion valve 10 of the present embodiment, the valve characteristics are stabilized, and the downstream refrigerant pressure can be made constant more reliably than in the past.

  In addition, the opening area of the clearance gap between one valve opening 16A and the contact shaft 37 among the bidirectional | two-way constant pressure expansion valves 10 of this embodiment is wider than the opening area of the clearance gap between the other valve opening 16B and the contact shaft 37. May be. In this way, the refrigerant flow rate controlled and flowed by the bidirectional constant pressure expansion valve 10 during one of the heating and cooling operations is larger than the refrigerant flow rate controlled and flowed during the other operation. It is possible to appropriately cope with, for example, a heating operation that requires a large flow rate.

[Second Embodiment]
The bidirectional constant pressure expansion valve 10 of the present embodiment is shown in FIG. 4, and a ring groove 44M is formed on the outer peripheral surface near the tip of the guide projection 44B, and made of a slidable resin (for example, fluorine This is different from the first embodiment in that a sliding ring 44E made of a resin is attached. Other configurations are the same as those in the first embodiment.

  According to the present embodiment, since the sliding ring 44E made of slidable resin is provided, the sliding resistance can be reduced and the weight of the movable part can be reduced, and the characteristics of the valve can be further stabilized. . The sliding ring 44E may be made of a resin or metal other than the slidable resin.

[Third Embodiment]
The bidirectional constant pressure expansion valve 10 of this embodiment is shown in FIG. Only the configuration different from that of the first embodiment will be described below.

  In the bidirectional constant pressure expansion valve 10 of the present embodiment, the inner diameter is gradually tapered with the inner surface of the base end portion of the cylindrical wall 13A provided on one opposing wall 13 (upper opposing wall 13 in FIG. 5) facing the back side. One conical recess 13T is formed with a reduced diameter. A flat cylindrical wall 13D protrudes from the outer edge of the other opposing wall 13, and the other conical recess 13T is formed with the inner surface tapered. The flange portion 44F in each movable counter board 44 includes a tapered surface 44T inclined at the same angle as the inner surface of each conical recess 13T, and constitutes a “conical entry portion” according to the present invention.

  According to the configuration of the present embodiment, when the bellows 41 moves between the opposing walls 13 and 13 and one end of the bellows 41 abuts against the opposing wall 13, a “conical ridge” is formed on one end side of the bellows 41. As a result of the guide of the flange portion 44F and the conical concave portion 13T, the movable counter board 44 is centered. Here, since the buckling of the bellows 41 is regulated by the buckling prevention mechanism 45, the entire bellows 41, the contact shaft 37 and the valve element 19 are centered by the centering of one end of the bellows 41 described above. Is done. As a result, the contact position between the contact shaft 37 and the valve body 19 is stabilized, the characteristics of the valve are also stabilized, and the downstream refrigerant pressure can be made constant more reliably than before.

  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) In the first to third embodiments, the contact shaft 37 is fixed to the movable counter plate 44 side. However, the contact shaft 37 may be fixed to the valve body 19 side.

  (2) In the first embodiment, the guide mechanism 44B and the guide recess 13U and the buckling prevention mechanism 45 cooperate to prevent the bellows 41 from buckling, but the guide protrusion 44B. Alternatively, the bellows 41 may be prevented from buckling only by a guide mechanism using the guide recess 13U.

Side sectional view of the bidirectional constant pressure expansion valve according to the first embodiment of the present invention. Side sectional view of bidirectional constant pressure expansion valve during cooling Conceptual diagram of heat pump circuit Side sectional view of the bidirectional constant pressure expansion valve of the second embodiment Side sectional view of the bidirectional constant pressure expansion valve of the third 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 13 Opposite wall 13T Guide recessed part 13U Conical recessed part 16A, 16B Valve port 17 Valve body urging spring 19 Valve body 37 Contact shaft 41 Bellows 44 Movable facing board 44B Guide protrusion 44E Sliding ring 44F Flange (conical entry)
45 Buckling prevention mechanism 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);
A bellows (41) accommodated in the intermediate region (R3) and extending in the opposing direction of the pair of opposing walls (13);
A pair of movable opposing boards (44) in which both ends of the bellows (41) are sealed;
The valve body (19) and the movable counter board (44) are fixed to either one of the valve body (19) and loosely fitted to the pair of valve ports (16A, 16B). The pair of the valve openings (16A, 16B) is changed by moving the valve element (19) according to the deformation amount of the bellows (41). A contact shaft (37) of
A guide protrusion (44B) protruding from the movable counter plate (44) toward the counter wall (13);
The guide protrusion (44B) is fitted into the end surface of the opposing wall (13) and the bellows (41), the contact shaft (37), and the valve body (19) are arranged coaxially. As described above, the bidirectional constant pressure expansion valve (10) is provided with a guide recess (13U) for centering the movable counter board (44).   The bidirectional constant pressure expansion valve (10) according to claim 1, wherein the guide recess (13U) and the guide protrusion (44B) are always fitted.   The bidirectional constant pressure expansion valve (10) according to claim 2, wherein a sliding ring (44E) is provided on one circumferential surface of the guide recess (13U) or the guide projection (44B).   The bidirectional constant pressure expansion valve (10) according to claim 3, wherein the sliding ring (44E) is made of a slidable resin. 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);
A bellows (41) accommodated in the intermediate region (R3) and extending in the opposing direction of the pair of opposing walls (13);
A pair of movable opposing boards (44) in which both ends of the bellows (41) are sealed;
The valve body (19) and the movable counter board (44) are fixed to either one of the valve body (19) and loosely fitted to the pair of valve ports (16A, 16B). The pair of the valve openings (16A, 16B) is changed by moving the valve element (19) according to the deformation amount of the bellows (41). A contact shaft (37) of
A conical intrusion portion (44F) formed in the movable facing plate (44) and having a reduced diameter in a tapered shape;
The inner wall is formed in the facing wall (13) and has a tapered inner diameter, and the cone-shaped protrusion (44F) is fitted into the bellows (41), the contact shaft (37), and the valve body. A conical recess (13T) for centering the movable facing plate (44) so that (19) are arranged coaxially;
A buckling prevention mechanism (45) that connects the pair of movable counters (44) and allows linear movement in a state where the movable counters (44) are held coaxially is provided. Bidirectional constant pressure expansion valve (10) characterized. 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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