JP4451407B2 - 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. 10 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 extend and contract. Specifically, the linear motion support mechanism 5 extends the support protrusions 5B and 5B from the movable plates 5A and 5A fixed to both ends of the bellows 4 so as to approach each other, and a support pin is attached to the support protrusions 5B and 5B. The support protrusions 5B and 5B are configured to be able to move directly with respect to each other while passing through 5C and restricting the relative inclination of the support 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. 10, the movable body 3 moves to the downstream side and comes into contact with the wall portion in the flow path 1, and one of the pressing shafts 6 is on 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)

  By the way, in the above-described conventional bidirectional constant pressure expansion valve, when the movable body 3 is displaced in the direction orthogonal to the linear motion direction within the clearance range between the side surface of the movable body 3 and the inner peripheral surface of the flow path 1, A moment load is applied between the connection pin 5C and the support protrusions 5B and 5B, and the sliding resistance between the connection pin 5C and the support protrusions 5B and 5B varies. As a result, the amount of expansion and contraction of the bellows 4 with respect to the refrigerant pressure also varies. For this reason, with the conventional bidirectional constant pressure expansion valve, it has been difficult to accurately set the refrigerant at a constant pressure.

  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 make a refrigerant at a constant pressure more accurately than before.

  In order to achieve the above object, the bidirectional constant pressure expansion valve (10, 30) according to the invention of claim 1 includes an indoor heat exchanger (92A) and an outdoor heat exchanger (91A) of the heat pump circuit (90). In the bidirectional constant pressure expansion valve (10, 30), which is connected between the two and is allowed to flow the refrigerant in both directions, and the refrigerant pressure on the downstream side can be kept constant, the refrigerant flow path (11) is provided inside. The body (10B) and a pair of opposing surfaces that are provided in the body (10B) and divide the flow path (11) into one end region (R1), an intermediate region (R3), and the other end region (R2). A wall (13, 13F) and a pair of opposed walls (13, 13F) are formed so as to penetrate the pair of valve ports (16A, 16B) disposed substantially coaxially, and fixed to the body (10B). In the one end side region (R1) and opposed to one valve port (16A) One end side pressure sensing part (20A) elastically deforming away from one valve port (16A) as the refrigerant pressure in the area (R1) rises, and the other end side area ( R2) is opposed to the other valve port (16B), and elastically deforms away from the other valve port (16B) as the refrigerant pressure in the other end region (R2) rises. It is accommodated in the part (20B) and the intermediate region (R3), moves between a pair of valve ports (16A, 16B), and can change the valve opening degree of the close valve port (16A, 16B) The movable valve body (17, 33) and the pair of valve ports (16A, 16B) are respectively loosely fitted, and depending on the position of the movable valve body (17, 33), the pressure sensitivity on one end side or the other end side Between one of the parts (20A, 20B) and the movable valve body (17, 33). Characterized in place and a pair of abutment shaft (17D, 34).

  According to a second aspect of the present invention, in the bidirectional constant pressure expansion valve (10, 30) according to the first aspect, the pressure-sensitive portions (20A, 20B) on one end side and the other end side are both open at one end. A diaphragm (22) is stretched at the open end of (21, 55), the pressure sensitive cylinder (21, 55) is fixed to the body (10B), and the diaphragm (22) faces the valve port (16A, 16B). It has a characteristic where it is placed.

  According to a third aspect of the present invention, in the bidirectional constant pressure expansion valve (10, 30) according to the second aspect, the outer edge of the diaphragm (22) is sandwiched between the opening edge of the pressure-sensitive cylinder (21, 55). And a diaphragm fixing plate (50) welded in, a through hole formed in the diaphragm fixing plate (50) to allow a refrigerant to pass through, and a through hole formed in the diaphragm fixing plate (50). A shaft insertion hole (52) through which the contact shaft (17D, 34) is inserted, and an opening edge of the shaft insertion hole (52), are usually opposed to the diaphragm (22) through a gap, and the diaphragm (22 ) Is provided with an excessive deformation preventing portion (53) that prevents the deformation of a predetermined amount or more.

  According to a fourth aspect of the present invention, in the bidirectional constant pressure expansion valve (10) of the third aspect, the pressure sensitive unit (55), the diaphragm (22), and the diaphragm fixing plate (50) are integrated. (57) and a press-fit cylinder portion (56) that protrudes from the opposing wall (13) and press-fits the pressure-sensitive unit (57) inward and can be held at an arbitrary position.

  According to a fifth aspect of the present invention, in the bidirectional constant pressure expansion valve (10, 30) according to any one of the first to fourth aspects, the gap between the one valve port (16A) and the contact shaft (17D, 34) is provided. It is characterized in that the opening area is wider than the opening area of the gap between the other valve port (16B) and the contact shaft (17D, 34).

  A sixth aspect of the present invention is the bidirectional constant pressure expansion valve (10, 30) according to any one of the first to fifth aspects, wherein the indoor heat exchange is performed in the pressure sensitive part (20A, 20B) on one end side or the other end side. The elastic coefficient of the pressure sensitive part (20B) on the side of the vessel (92A) is different from the elastic coefficient of the pressure sensitive part (20A) on the side of the outdoor heat exchanger (91A).

  A seventh aspect of the present invention is the bidirectional constant pressure expansion valve (10) according to any one of the first to sixth aspects, wherein the pair of contact shafts (17D) extend from both ends of the movable valve body (17). It is characterized by where it is installed.

  An eighth aspect of the present invention is the bidirectional constant pressure expansion valve (30) according to any one of the first to seventh aspects, wherein the pair of contact shafts (34) are connected to the pressure-sensitive portions on the other end side and one end side ( 20A and 20B), and the movable valve element (33) is composed of a spherical body (33).

  The bidirectional constant pressure expansion valve (10, 30) of claim 1 is connected between the outdoor heat exchanger (91A) and the indoor heat exchanger (92A) of the heat pump circuit (90), and the heat pump circuit (90) is cooled. When one of the operation and the heating operation is performed, the bidirectional constant pressure expansion valve (10, 30) includes one end side region (R1), one valve port (16A), an intermediate region (R3), and the other valve port. (16B), the refrigerant flows in the order of the other end side region (R2). Then, the movable valve body (17, 33) in the intermediate region (R3) is pushed by the refrigerant and moves downstream, and the contact shaft (17D, 34) loosely fitted in the downstream valve port (16B). However, it will be in a stretch state between a movable valve body (17, 33) and a pressure sensing part (20B) at the other end. Thereby, a movable valve body (17, 33) is positioned by the other end side pressure sensing part (20B).

  Here, when the refrigerant pressure in the other end side region (R2) becomes relatively large, the other end side pressure sensing portion (20B) is deformed away from the valve port (16B), and accordingly, the movable valve body ( 17, 33) approaches the valve port (16B), the valve opening decreases, and the refrigerant pressure in the other end side region (R2) decreases. On the contrary, when the refrigerant pressure in the other end side region (R2) becomes relatively small, the other end side pressure sensing portion (20B) is deformed so as to approach the valve port (16B), and is moved accordingly. The valve body (17, 33) is separated from the valve port (16B), the valve opening is increased, and the refrigerant pressure in the other end region (R2) is increased. As a result, the downstream refrigerant pressure in the bidirectional constant pressure expansion valve (10, 30) becomes constant.

  Similarly, when the cooling operation and the heating operation are switched and the direction in which the refrigerant flows is reversed from that in the above case and the one end side region (R1) is located on the downstream side, the refrigerant pressure in the one end side region (R1) is the same. Is relatively large, the valve opening degree of one of the valve openings (16A) is reduced and the refrigerant pressure on the downstream side rises. On the other hand, when the refrigerant pressure in the one end region (R1) is relatively small, the valve opening (16A) ), The downstream refrigerant pressure decreases, and the downstream refrigerant pressure becomes constant. Regardless of the direction in which the refrigerant flows, the movable valve element (17, 33) moves downstream so that the gap between the movable valve element (17, 33) and the upstream valve opening (16A, 16B) The valve ports (16A, 16B) on the upstream side are always opened and always open.

  Thus, according to the bidirectional constant pressure expansion valve (10, 30) of the present invention, the downstream refrigerant pressure can be made constant. Moreover, since the pressure sensitive parts (20A, 20B) on one end side and the other end side are fixed to the body (10B), the pressure sensitive parts (20A, 20B) themselves on the one end side and the other end side flow in the refrigerant. Will not move in response to. Therefore, a linear motion support mechanism that restricts the buckling of the bellows and supports the bellows so as to be extendable / contracted as in the prior art becomes unnecessary. Thereby, the influence of the sliding resistance of the linear motion support mechanism is eliminated, and the refrigerant can be kept at a constant pressure more accurately than in the past.

  The one end side pressure sensing part (20A) and the other end side pressure sensing part (20B) in the bidirectional constant pressure expansion valve (10, 30) of the present invention include either the diaphragm (22) or the bellows, so that the refrigerant pressure It can be configured to be deformed according to the above. Further, in the case of the configuration including the diaphragm (22), for example, as in the invention of claim 2, the diaphragm (22) is stretched over the opening of the pressure-sensitive cylinder (21) that is open at one end, and the pressure-sensitive cylinder. What is necessary is just to fix a body (21) to a body (10B).

  According to the bidirectional constant pressure expansion valve (10, 30) of claim 3, the outer edge portion of the diaphragm (22) is sandwiched between the opening edge of the pressure sensitive cylinder (21, 55) and the diaphragm fixing plate (50). The diaphragm (22) is stably fixed to the pressure-sensitive cylinder (21, 55). Moreover, the excessive deformation | transformation prevention part (53) with which the diaphragm fixing plate (50) was equipped is made to contact the diaphragm (22) which deform | transformed predetermined amount directly or indirectly, and an excessive deformation | transformation of a diaphragm (22) is prevented. can do.

  According to the bidirectional constant pressure expansion valve (10) of claim 4, each configuration of the bidirectional constant pressure expansion valve (10) is adjusted by appropriately adjusting the press-fitting position of the pressure-sensitive unit (57) with respect to the press-fitting cylinder portion (56). The quality of the bidirectional constant pressure expansion valve (10) can be made uniform by suppressing the influence due to the dimensional variation of the parts.

  In addition, unlike the conventional bidirectional constant pressure expansion valve, the bidirectional constant pressure expansion valve (10, 30) of the present invention is provided with the pressure sensitive parts (20A, 20B) in pairs on one end side and the other end side. The characteristics of the valve opening with respect to the refrigerant pressure of the valve opening (16B) on the indoor heat exchanger (92A) side, and the characteristics of the valve opening with respect to the refrigerant pressure of the valve opening (16A) on the outdoor heat exchanger (91A) side Can be set to characteristics suitable for each.

  Specifically, as in the bi-directional constant pressure expansion valve (10, 30) of claim 5, one of the valve ports (16A) and the contact shaft (17D, 34) located on the downstream side during either heating or cooling operation. ) May be wider than the opening area of the gap between the other valve port (16B) and the contact shaft (17D, 34). As a result, the refrigerant flow rate controlled and flowed by the bidirectional constant pressure expansion valve (10, 30) 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 the heating operation that requires a large flow rate (large capacity).

  Further, as in the bi-directional constant pressure expansion valve (10, 30) of claim 6, the indoor heat exchanger (10A, 20B) located on the downstream side during the cooling operation of the pressure sensing part (20A, 20B) on one end side or the other end side. The elastic coefficient of the pressure-sensitive part (20B) on the 92A) side and the elastic coefficient of the pressure-sensitive part (20A) on the outdoor heat exchanger (91A) side located on the downstream side during the heating operation are made different from each other. It is possible to obtain an optimal valve lift characteristic capable of controlling the pressure and flow rate of the refrigerant during cooling operation and heating operation with different refrigerant flow rates.

  According to the structure of Claim 7, since a pair of contact shaft (17D) is extended from the both ends of the movable valve body (17), the pressure-sensitive part (20A, 20B) can be simplified.

  As in the configuration of the eighth aspect, the pair of contact shafts (34) are fixed to the pressure-sensitive portions (20A, 20B) on the other end side and the one end side, respectively, and the movable valve body (33) is a spherical body. (33) may be used.

[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 opposed walls 13 and 13 are separate parts from the pipe member 12, and a cylindrical guide cylinder 15 </ b> A is provided between the opposed walls 13 and 13. A circular recess 15B is formed at the center of each opposing wall 13, and each end of the guide cylinder 15A is fitted in the circular recess 15B of each opposing wall 13. Thereby, the opposing walls 13 and 13 are centered on each other. Moreover, the front end of the guide cylinder 15A is abutted against the inner surface of the circular recess 15B to position the opposing walls 13 and 13, and the interval between the opposing walls 13 and 13 is constant.

  Locking grooves 14 are 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. And each protrusion 12T is engaged in the locking groove 14 of each opposing wall 13 and 13, and the opposing walls 13 and 13 are positioned and fixed in the pipe member 12, and the outer peripheral surface 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. Further, the guide cylinder 15A and the circular recess 15B described above are arranged on concentric circles of the valve ports 16A and 16B. Further, the inner diameter of the valve port 16A of the one opposing wall 13 (the upper valve port 16A in FIG. 1) is larger than the inner diameter of the valve port 16B of the other opposing wall 13. 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 intermediate region R3 side in both valve ports 16A and 16B.

  Refrigerant passage holes 15C penetrating the guide cylinder 15A in a direction orthogonal to the axial direction are formed at both ends of the guide cylinder 15A, respectively, and the refrigerant passes through the refrigerant passage holes 15C to the inside and outside of the guide cylinder 15A. Flowing between. Further, tapered surfaces 15T and 15T are formed on the opposing walls 13 and 13 so as to surround both end portions of the guide cylinder 15A. For example, the refrigerant flowing from the refrigerant passage hole 15C on the one end side toward the outside of the guide cylinder 15A is guided in the axial direction of the guide cylinder 15A by the tapered surface 15T on the one end side, and the outer surface of the guide cylinder 15A. It plays a role of guiding the refrigerant flowing along the other end side into the refrigerant passage hole 15C on the other end side by the tapered surface 15T on the other end side.

  A movable valve body 17 is accommodated in the guide cylinder 15A. The movable valve body 17 has a cylindrical structure extending in the same direction as the guide cylinder 15A, and tapers toward both ends. Specifically, the movable valve body 17 includes a sliding portion 17A at the axial center, and abuts the loose fitting portion 17B and the valve portion 17C from both ends of the sliding portion 17A toward both ends. A shaft 17D is provided in order.

  The sliding portion 17A has a size capable of sliding on the inner surface of the guide cylinder 15A, whereby the movable valve body 17 is centered on the guide cylinder 15A and the valve ports 16A and 16B.

  Each contact shaft 17D, 17D is loosely fitted to each valve port 16A, 16B. And a refrigerant | coolant flows through valve opening 16A, 16B through the clearance gap between the internal peripheral surface of each valve opening 16A, 16B, and the outer peripheral surface of contact shaft 17D, 17D. Moreover, both contact shafts 17D and 17D have the same outer diameter. As described above, since the inner diameter of one valve port 16A is larger than the inner diameter of the other valve port 16B, the opening area of the gap between one valve port 16A and the contact shaft 17D is the other valve port 16B. And the opening area of the gap between the contact shaft 17D and the contact shaft 17D.

  Both loose fitting portions 17B and 17B have a stepped diameter with respect to the sliding portion 17A, and the gap formed between the loose fitting portion 17B and the inner surface of the guide cylinder 15A is filled with refrigerant. It is large enough to pass.

  The valve portion 17C has a tapered shape in which one end has the same outer diameter as the loose fitting portion 17B and the other end has the same outer diameter as the contact shaft 17D. Further, the inclination of the taper of the valve portion 17C is, for example, the same angle as the inclination of the tapered valve seat 16Z provided at the opening edges of the valve ports 16A and 16B. Then, as shown in FIG. 3, when the movable valve body 17 moves to the one end side within the guide cylinder 15A, one valve portion 17C approaches one valve port 16A and the valve opening degree of the valve port 16A is adjusted. At the same time, the other valve portion 17C is sufficiently separated from the other valve port 16B, and the valve port 16B is opened. On the contrary, when the movable valve body 17 moves to the other end side within the guide cylinder 15A as shown in FIG. 1, the other valve portion 17C approaches one valve port 16B, and the valve port 16B While the valve opening can be adjusted, the one valve portion 17C is sufficiently separated from the other valve port 16A, and the valve port 16A is opened.

  In order to adjust the valve opening degree of each valve port 16A, 16B, each opposing wall 13, 13 as a part of the body 10B is provided with one end side pressure sensing portion 20A and the other end side pressure sensing portion 20B according to the present invention. And are assembled.

  The one-end-side pressure-sensitive portion 20A and the other-end-side pressure-sensitive portion 20B are both formed by extending a diaphragm 22 over the opening of the pressure-sensitive cylinder 21 that is open at one end. As shown in FIG. 4, the cylinder wall of the pressure-sensitive cylinder 21 has an outer diameter on the opening end side that is enlarged in a stepped manner in the middle, and a flange portion 21F projects laterally from the opening end of the cylinder wall. Has been. A diaphragm fixing plate 50 is provided at a position sandwiching the diaphragm 22 with respect to the pressure sensitive cylinder 21. The diaphragm fixing plate 50 has a flat cylindrical shape with a bottom at one end, and a flange portion 50F projects from the opening end to the side. The flange portion 50F has the same shape as the flange portion 21F of the pressure-sensitive cylinder 21. The outer edge portion of the diaphragm 22 is sandwiched between the flange portions 21F and 50F, and both the flange portions 21F and 50F and the diaphragm 22 are welded. Yes. Further, the excessive deformation preventing portion 53 bulges toward the diaphragm 22 from the center portion of the bottom wall 50B of the diaphragm fixing platen 50. And the front end surface of the excessive deformation | transformation prevention part 53 is in the state facing the center part of the diaphragm 22. As shown in FIG. As a result, when the diaphragm 22 is bent to a predetermined amount toward the diaphragm fixing plate 50, the diaphragm 22 comes into contact with the excessive deformation preventing portion 53, and excessive deformation is prevented.

  A shaft insertion hole 52 through which the contact shaft 17 </ b> D can be inserted is formed through the center of the distal end surface of the excessive deformation preventing portion 53. A plurality of refrigerant passage holes 51 are formed through the bottom wall 50B around the excessive deformation preventing portion 53.

  A compression coil spring 24 is accommodated inside the pressure-sensitive cylinder 21, and one end of the compression coil spring 24 is pressed against the inner support plate 23 that is directed to the inner surface of the diaphragm 22. The center portion of the inner support plate 23 protrudes toward the diaphragm 22, and only the front end surface of the protruding portion is in contact with the diaphragm 22. Further, the outer edge portion of the inner support plate 23 is opposed to the step portion 21 </ b> D of the cylindrical wall in the pressure-sensitive cylindrical body 21 via a gap. And when the diaphragm 22 bends to the back side of the pressure-sensitive cylinder 21 to a predetermined amount, the inner support plate 23 and the stepped portion 21D come into contact with each other to prevent excessive deformation of the diaphragm 22.

  The pressure sensitive cylinder 21 is configured to keep the inside at a constant pressure such as vacuum or atmospheric pressure. Further, the annular protrusion 18 is formed with a through hole 18A in a direction orthogonal to the axial direction, and the space between the diaphragm 22 and the opposing wall 13 through the through hole 18A is one end side region R1 (or The other end side region R2) communicates with the whole.

  A plurality of components such as the pressure-sensitive cylinder 21, the diaphragm 22, the inner support plate 23, the compression coil spring 24, and the diaphragm fixing plate 50 are integrated by the above-described welding to form a pressure-sensitive unit 57. In order to attach the pressure-sensitive unit 57 to each of the opposing walls 13 and 13, an annular protrusion 18 is formed on the outer surface of the opposing walls 13 and 13 opposite to the intermediate region R3. A locking piece 19 stands up from the outer edge of the annular protrusion 18. Then, the cylindrical wall 50A of the diaphragm fixing plate 50 in the pressure-sensitive unit 57 is pushed into the annular projecting portion 18 for centering, and the outer edge portions of the flange portions 21F and 50F are pressed against the end surface of the annular projecting portion 18. With the axial direction positioned, the locking piece 19 is pushed down toward the flange portions 21F and 50F. Thereby, the pressure-sensitive units 57 and 57 are fixed to the opposing walls 13 and 13 to constitute the one-end-side pressure-sensitive portion 20A and the other-end-side pressure-sensitive portion 20B.

  The combined elastic coefficient of the diaphragm 22 and the compression coil spring 24 is different between the pressure-sensitive portions 20A and 20B (see FIG. 1) on one end side and the other end side. Specifically, the elastic coefficient of the other end side pressure sensitive part 20B is larger than the elastic coefficient of the one end side pressure sensitive part 20A. Further, as described above, the opening area of the gap between one valve port 16A and the contact shaft 17D is larger than the opening area of the gap between the other valve port 16B and the contact shaft 17D, and these elastic coefficients. And the opening area are set to a predetermined value and combined so that the refrigerant pressure in the other end region R2 when the other end region R2 is downstream is the same as that when the one end region R1 is downstream. It is comprised so that it may become larger than the refrigerant | coolant pressure of one end side area | region R1.

  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. 5 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 pipe 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 valve element 17 in the intermediate region R3 is pushed by the refrigerant and moves downstream (in this case, the lower side in FIG. 1), and the contact shaft 17D loosely fitted in the downstream valve port 16B is The movable valve element 17 and the pressure sensor 20B on the other end side are stretched. Thereby, the movable valve body 17 is positioned by the other end side pressure sensing part 20B.

  Here, when the refrigerant pressure in the other end side region R2 becomes relatively large, the diaphragm 22 of the other end side pressure sensing portion 20B is deformed so as to be separated from the valve port 16B, and accordingly, the movable valve body 17 is moved to the valve port. The valve opening degree decreases toward 16B, and the refrigerant pressure in the other end region R2 decreases. On the contrary, when the refrigerant pressure in the other end side region R2 becomes relatively small, the diaphragm 22 of the other end side pressure sensing portion 20B is deformed so as to approach the valve port 16B, and accordingly, the movable valve body 17 is deformed. Is away from the valve port 16B, the valve opening increases, and the refrigerant pressure in the other end region R2 increases. Thereby, the refrigerant pressure on the downstream side can be made constant.

  On the other hand, when the heat pump circuit 90 is switched from the cooling operation to the heating operation, the direction in which the refrigerant flows is reversed, and as indicated by the arrows in FIG. 2, the refrigerant is in the other end side region R2, the other valve port 16B, and the intermediate region. It flows in the order of R3, one valve port 16A, and one end side region R1. Then, as shown in the change from FIG. 2 to FIG. 3, the movable valve body 17 in the intermediate region R3 is pushed by the refrigerant and moves to the downstream side (in this case, the upper side in FIG. 3). The contact shaft 17D loosely fitted in the port 16A is in a stretched state between the movable valve body 17 and the one-end-side pressure sensitive part 20A. Thereby, the movable valve body 17 is positioned by the one-end-side pressure sensitive part 20A.

  As in the cooling operation, when the refrigerant pressure in the one end side region R1 becomes relatively large, the movable valve body 17 approaches the valve port 16A and the valve opening decreases accordingly, and the one end side region R1. The refrigerant pressure inside decreases. On the other hand, when the refrigerant pressure in the other end side region R2 becomes relatively small, the movable valve body 17 moves away from the valve port 16B and the valve opening increases accordingly. The refrigerant pressure increases. Thereby, the refrigerant pressure on the downstream side can be made constant.

  Thus, according to the bidirectional constant pressure expansion valve 10 of the present embodiment, the refrigerant pressure on the downstream side can be made constant regardless of the direction in which the refrigerant flows. In the bidirectional constant pressure expansion valve 10 according to the present embodiment, the pressure-sensitive portions 20A and 20B on one end side and the other end side are fixed to the body 10B. 20B itself does not move according to the direction in which the refrigerant flows. Therefore, a linear motion support mechanism that restricts the buckling of the bellows and supports the bellows so that it can be expanded and contracted is not required. Thereby, the influence of the sliding resistance of the linear motion support mechanism is eliminated, and the refrigerant can be kept at a constant pressure more accurately than in the past. In addition, since the movable valve body 17 is guided by the guide cylinder 15A so as to be capable of linear movement, the correspondence between the linear movement position of the movable valve body 17 and the valve opening is more stable than in the prior art. It becomes possible to make the refrigerant at a constant pressure more accurately.

  Further, unlike the conventional bidirectional constant pressure expansion valve, the bidirectional constant pressure expansion valve 10 of the present embodiment is provided with the pressure sensitive portions 20A and 20B in pairs on one end side and the other end side, so that the indoor heat exchanger The characteristic of the valve opening degree with respect to the refrigerant pressure of the 92A side valve opening 16B and the characteristic of the valve opening degree with respect to the refrigerant pressure of the valve opening 16A of the outdoor heat exchanger 91A side may be set to appropriate characteristics. it can. In the bidirectional constant pressure expansion valve 10 of the present embodiment, the downstream refrigerant pressure during the cooling operation is configured to be greater than the downstream refrigerant pressure during the heating operation, so that the cooling operation and the heating operation are performed. The refrigerant controlled to the optimum temperature and pressure can be supplied to the outdoor and indoor heat exchangers 91A and 92A.

  Moreover, since the opening area of the gap between the one valve port 16A and the contact shaft 17D located on the downstream side during the heating operation is made larger than the opening area of the gap between the other valve port 16B and the contact shaft 17D, It is possible to appropriately cope with the heating operation with a relatively large flow rate.

  Further, the refrigerant pressure and the refrigerant are changed by making the elastic coefficient of the other pressure sensing section 20B located downstream during the cooling operation different from the elastic coefficient of the one pressure sensing section 20A located downstream during the heating operation. Optimal valve lift characteristics can be obtained during cooling operation and heating operation with different flow rates.

[Second Embodiment]
This embodiment is different from the first embodiment in that the position of the pressure-sensitive unit 57 with respect to the facing wall 13 can be adjusted. Specifically, as shown in FIG. 6, each opposing wall 13 of the present embodiment has a press-fit cylinder portion 56 from the outer edge portion of the annular projection 18 instead of the locking piece 19 of the first embodiment. Protrusions are formed. Further, the pressure-sensitive cylinder 55 is provided with a press-fit shaft portion 55K having an outer diameter larger than that of the flange portion 21F for fixing the diaphragm 22, and the pressure-sensitive shaft portion 55K is press-fitted into the press-fit cylinder portion 56 so The unit 57 can be held at an arbitrary position with respect to the facing wall 13. Since the configuration other than the above is the same as that of the first embodiment, a duplicate description is omitted.

  The position of the pressure-sensitive unit 57 of this embodiment is adjusted as follows. That is, the pressure-sensitive unit 57 is press-fitted relatively shallowly into the press-fitting cylinder portion 56 of each opposing wall 13, and each of the sensations is located at a position where the contact shaft 17D is in contact with the diaphragm 22 and the valve ports 16A and 16B are slightly opened. The pressure unit 57 is arranged to complete the assembly of the bidirectional constant pressure expansion valve 10. For example, in order to adjust the pressure sensing unit 57 in the other pressure sensing portion 20B, an orifice 60 for restricting the flow rate is attached to the opening end of the pipe member 12 on the other pressure sensing portion 20B side, and the middle A pressure gauge (not shown) for detecting the pressure in the region R3 is attached.

  In this state, the one end side region R1 of the bidirectional constant pressure expansion valve 10 is set to a predetermined pressure (for example, 2 MPa). Then, the diaphragm 22 of the other pressure sensor 20B bends to the back side of the pressure sensing cylinder 21 due to the pressure of the refrigerant flowing into the other region R2 through the valve port 16B. At this time, if the amount of press-fitting into the press-fitting cylinder portion 56 of the pressure-sensitive unit 57 on the other end-side pressure sensing portion 20B side is insufficient, the pressure in the intermediate region R3, that is, the pressure downstream of the bidirectional constant pressure expansion valve 10 The valve port 16B is maintained in a closed state even if the pressure falls below a designed reference pressure (for example, 0.5 MPa). In that case, the pressure sensing unit 57 on the other end pressure sensing portion 20B side is slightly pushed in, and then the inside of the one end region R1 of the bidirectional constant pressure expansion valve 10 is again set to a predetermined pressure. Then, the pressure-sensitive unit 57 may be pushed to a position where the inside of the intermediate region R3 is held at a reference pressure as designed and the valve port 16B is kept open. And the position adjustment operation | work of the pressure sensitive unit 57 in the one end side pressure sensitive part 20A should just be performed by the same method.

  As described above, according to the bidirectional constant pressure expansion valve 10, by appropriately adjusting the position where the pressure sensitive unit 57 is press-fitted into the press-fitting cylinder portion 56, the influence due to the dimensional variation of each component of the bidirectional constant pressure expansion valve 10 is affected. The quality of the bidirectional constant pressure expansion valve 10 can be made uniform. In order to easily perform the above-described press-fitting work, the pressure-sensitive unit 57 may be fixed to the press-fitting cylinder portion 56 by screw fitting.

[Third Embodiment]
The bidirectional constant pressure expansion valve 30 of this embodiment is shown in FIG. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals, and redundant description will be omitted, and only components different from those in the first embodiment will be described.

  In FIG. 7, reference numeral 31 denotes a first inner wall structure, which has a structure in which the outer diameter of one of the opposing walls 13 in the first embodiment is slightly reduced and the locking protrusion 31 </ b> A is projected from the outer peripheral surface. It has become. Reference numeral 32 denotes a second inner wall constituting body, and a locking protrusion 31B is projected from the outer edge of the other opposing wall 13 in the first embodiment to the side opposite to the other pressure sensing portion 20B. It has a structure. Then, the first end surfaces of the first inner wall constituting body 31 and the second inner wall constituting body 32 are joined to each other, the engaging protrusion 31B is bent inward and engaged with the engaging protrusion 31A. The inner wall constituting body 31 and the second inner wall constituting body 32 are integrated.

  A recessed portion 38 having a circular cross section is formed on the joint surface with the first inner wall constituting body 31 at the central portion of the second inner wall constituting body 32, while a cylindrical protrusion is formed at the central portion of the first inner wall constituting body 31. 39 is formed. Then, the cylindrical protrusion 39 is fitted into the depressed portion 38, the inside of the cylindrical protruding portion 39 forms an intermediate region R3 according to the present invention, and the inner walls of the depressed portion 38 and the cylindrical protruding portion 39 are included in the present invention. The pair of opposing walls 13F and 13F is used. And the spherical body 33 as a movable valve body which concerns on this invention is accommodated in the inside of intermediate | middle area | region R3.

  In addition, each diaphragm 22 of the one end-side pressure sensing portion 20A and the other end-side pressure sensing portion 20B has one end portion of the contact shaft 34 fixed to the center portion, and the other end portion of the contact shaft 34 is the shaft insertion hole. 52 and the valve ports 16A and 16B. Further, a large diameter portion 34 </ b> D is provided at one end portion of the contact shaft 34. Further, the bottom wall 50B of the diaphragm fixing plate 50 of the present embodiment is flat, the shaft insertion hole 52 is disposed at the center of the bottom wall 50B, and the opening edge of the shaft insertion hole 52 is the excessive deformation preventing portion 53. It has become. The excessive deformation preventing portion 53 is normally opposed to the large diameter portion 34D of the contact shaft 34 via a gap to prevent excessive deformation of the diaphragm 22.

  According to the bidirectional constant pressure expansion valve 30 of the present embodiment, when the refrigerant flows downward in FIG. 7, the sphere 33 moves to the valve port 16B side, and between the valve seat 16Z of the valve port 16B and the sphere 33. A gap is formed. When the pressure in the other end side region R2 becomes relatively high, the sphere 33 approaches the valve seat 16Z of the valve port 16B and the valve opening becomes small, and when the pressure in the other end side region R2 becomes relatively small. The spherical body 33 is separated from the valve seat 16Z of the valve port 16B, and the valve opening degree is increased. Thereby, the refrigerant | coolant pressure of other end side area | region R2 is hold | maintained uniformly.

  When the direction in which the refrigerant flows is reversed, the sphere 33 moves to the valve port 16A side. Similarly, the valve opening degree of the valve port 16A is adjusted according to the refrigerant pressure in the one end side region R1, and the one end side The refrigerant pressure in the region R1 is kept constant.

[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) The one-end-side pressure-sensitive portion 20A and the other-end-side pressure-sensitive portion 20B of the first to third embodiments include the diaphragm 22, but instead of the diaphragm 22, the bellows is replaced with the one-end-side pressure-sensitive portion. And you may make it the structure provided in the other end side pressure sensing part.

  (2) Although the body 10B of the first to third embodiments is configured by assembling the pipe member 12 and the opposing wall 13 (13F), the opposing wall 13 (13F) is integrally formed with the pipe member 12. These are also included in the technical scope of the present invention.

  (3) A configuration in which the diaphragm fixing plate 50 is removed from the bidirectional constant pressure expansion valve 10 of the first embodiment as shown in FIG. 8, or a bidirectional constant pressure expansion valve of the third embodiment as shown in FIG. What excluded the diaphragm fixed board 50 from 30 is also contained in the technical scope of this invention.

  (4) Although the first embodiment is configured such that the refrigerant pressure on the downstream side is different between the heating operation and the cooling operation, the configuration of both ends of the bidirectional constant pressure expansion valve described above is the same. Thus, the refrigerant pressure on the downstream side may be the same during the heating operation and during the 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 A side sectional view enlarging a part 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 bidirectional constant pressure expansion valve according to a third embodiment Side sectional view of a modified bi-directional constant pressure expansion valve Side sectional view of a modified bi-directional constant pressure expansion valve Side sectional view of a conventional bidirectional constant pressure expansion valve

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,30 Bidirectional constant pressure expansion valve 10B Body 11 Flow path 13,13F Opposite wall 15A Guide cylinder 15C Refrigerant passage hole 16A, 16B Valve port 17 Movable valve body 17D, 34 Contact shaft 20A One end side pressure sensing part 20B The other end Side pressure sensing unit 21 Pressure sensing cylinder 22 Diaphragm 33 Sphere 50 Diaphragm fixing plate 51 Refrigerant passage hole 52 Shaft insertion hole 53 Excessive deformation prevention part 57 Pressure sensing unit 90 Heat pump circuit 91A Outdoor heat exchanger 92A Indoor heat exchanger R1 One end side Region R2 Other end region R3 Intermediate region

Claims (8)

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, 30),
A body (10B) having a flow path (11) for the refrigerant therein;
A pair of opposing walls (13, 13F) provided in the body (10B) and partitioning the flow path (11) into one end side region (R1), an intermediate region (R3), and the other end side region (R2). )When,
A pair of valve ports (16A, 16B) that are formed through the pair of opposing walls (13, 13F) and arranged substantially coaxially;
It is fixed to the body (10B), and is disposed opposite to one of the valve ports (16A) in the one end side region (R1), and as the refrigerant pressure in the one end side region (R1) increases, One end side pressure sensing part (20A) elastically deforming away from the valve opening (16A);
It is fixed to the body (10B), is disposed opposite to the other valve port (16B) in the other end side region (R2), and the refrigerant pressure in the other end side region (R2) increases as the refrigerant pressure increases. The other end side pressure sensitive part (20B) elastically deformed away from the other valve port (16B),
A movable valve that is accommodated in the intermediate region (R3), moves between the pair of valve ports (16A, 16B), and can change the valve opening degree of the valve ports (16A, 16B) on the approaching side. Body (17, 33),
Depending on the position of the movable valve body (17, 33), either one of the pressure sensing parts (20A, 20B) on the one end side or the other end side is loosely fitted to the pair of valve ports (16A, 16B). A bidirectional constant pressure expansion valve (10, 30) comprising a pair of abutting shafts (17D, 34) that are stretched between the movable valve element (17, 33). .   The pressure-sensitive portions (20A, 20B) on the one end side and the other end side are each formed by placing a diaphragm (22) on the open end of a pressure-sensitive cylinder (21, 55) that is open at one end. 21. The bidirectional constant pressure expansion valve according to claim 1, wherein 21, 55) is fixed to the body (10 </ b> B), and the diaphragm (22) is disposed to face the valve port (16 </ b> A, 16 </ b> B). 10, 30). A diaphragm fixing plate (50) welded with an outer edge portion of the diaphragm (22) sandwiched between opening edges of the pressure-sensitive cylinders (21, 55);
A refrigerant passage hole (51) formed through the diaphragm fixed platen (50) to allow the refrigerant to pass through;
A shaft insertion hole (52) formed through the diaphragm fixing plate (50) and through which the contact shaft (17D, 34) is inserted;
An over-deformation preventing portion (provided at an opening edge of the shaft insertion hole (52)) and facing the diaphragm (22) through a gap to prevent the diaphragm (22) from being deformed more than a predetermined amount ( 53), the bidirectional constant pressure expansion valve (10, 30) according to claim 2. A pressure-sensitive unit (57) in which the pressure-sensitive cylinder (55), the diaphragm (22), and the diaphragm fixing plate (50) are integrated;
The press-fitting cylinder part (56) which protrudes from the said opposing wall (13), press-fits the said pressure-sensitive unit (57) inside, and can hold | maintain in arbitrary positions is provided. Bidirectional constant pressure expansion valve (10).   The opening area of the gap between the one valve port (16A) and the contact shaft (17D, 34) is the opening area of the gap between the other valve port (16B) and the contact shaft (17D, 34). The bidirectional constant pressure expansion valve (10, 30) according to any one of claims 1 to 4, characterized in that it is wider.   The elastic coefficient of the pressure sensitive part (20B) on the indoor heat exchanger (92A) side of the pressure sensitive part (20A, 20B) on the one end side or the other end side, and the feeling on the outdoor heat exchanger (91A) side. The bidirectional constant pressure expansion valve (10, 30) according to any one of claims 1 to 5, wherein the pressure coefficient (20A) has a different elastic coefficient.   The bidirectional constant pressure expansion valve (10) according to any one of claims 1 to 6, wherein the pair of contact shafts (17D) extend from both ends of the movable valve body (17). ). The pair of abutting shafts (34) are fixed to the pressure-sensitive portions (20A, 20B) on the other end side and the one end side, respectively, and the movable valve body (33) is configured by a spherical body (33). A bidirectional constant pressure expansion valve (30) according to any of the preceding claims, characterized in that it is characterized in that

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