valve

Abstract

The purpose of the present invention is to provide a valve having high precision in valve opening adjustment.　This valve V1 comprises: a valve housing 10 in which is formed an inlet port 11 and an outlet port 12; a valve body 51 driven by a drive source 80; a valve seat 40a on which the valve body 51 sits; and a spring 85 which biases the valve body 51 in a direction opposite to the drive direction of the drive source 80. The valve V1 also comprises a communication means 21 which enables communication of a space S, on the rear side of the valve body 51, with the inlet port 11.

Description

[Technical Field]

[0001] The present invention relates to a valve used in an air conditioning system, for example, to a valve used in an air conditioning system. [Background technology]

[0002] An air conditioning system is mainly composed of a compressor that compresses refrigerant to form superheated vapor, a condenser that cools the refrigerant sent from the compressor to form a supercooled liquid, an expansion valve that expands the refrigerant sent from the condenser to form wet vapor, and an evaporator that heats the refrigerant sent from the expansion valve to form saturated vapor, and is equipped with a refrigeration cycle in which the refrigerant circulates through the compressor, condenser, expansion valve, and evaporator in that order.

[0003] For example, the valve in Patent Document 1 is an electronic expansion valve that uses the electromagnetic force of a solenoid as a drive source to drive a valve element in the valve opening direction against the biasing force of a spring, thereby adjusting the valve opening between the valve element and a valve seat formed in a valve housing. Also, the value of the current applied to the solenoid is set based on the temperature and pressure of the refrigerant after passing through the condenser, and the valve opening is adjusted to maintain a constant degree of subcooling in the condenser.

[0004] In addition, a system is also known in which the opening degree of the expansion valve is adjusted based on the temperature and pressure of the refrigerant before or after passing through the evaporator, thereby adjusting the dryness of the wet steam so that all the refrigerant becomes saturated vapor after passing through the evaporator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-153498 A (page 2, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In a valve such as that described in Patent Document 1, the through-flow passage is closed by a valve body and a valve seat, and thus the through-flow passage can be closed reliably. However, in a valve such as that described in Patent Document 1, a high-pressure primary-pressure refrigerant is supplied to the through-flow passage from the condenser, and therefore a force due to the pressure of the refrigerant is applied to the valve body in the valve opening direction in addition to the driving force of the solenoid, and there is a risk that the valve opening degree in response to the value of current applied to the solenoid will vary slightly depending on the pressure of the refrigerant.

[0007] The present invention has been made in view of these problems, and has as its object to provide a valve with high accuracy in adjusting the valve opening degree. [Means for solving the problem]

[0008] In order to solve the above problems, the valve of the present invention comprises: a valve housing having an inlet port and an outlet port formed therein; a valve body driven by a drive source; a valve seat on which the valve body is seated; a spring that biases the valve body in a direction opposite to the driving direction of the drive source, A communication means is provided to allow communication between the inlet port and the space on the back side of the valve body. According to this, when the inlet port and the space behind the valve disc are connected by the connecting means, a fluid, for example, a refrigerant at a primary pressure flowing from a condenser into the inlet port is supplied to the space behind the valve disc. This reduces the effect of the force of the refrigerant at the primary pressure acting on the valve disc, thereby improving the accuracy of valve opening adjustment. Furthermore, by supplying refrigerant at a primary pressure to the space behind the valve disc, it is possible to reduce the driving force of the drive source near the closed position. The space behind the valve disc is located closer to the drive source than the valve seat.

[0009] The space on the back side of the valve body may be connected to the outlet port via a throttle. According to this, the space on the back side of the valve body is maintained at a pressure close to the primary pressure by the throttle.

[0010] The throttle may be formed by a guide hole in the valve housing and a valve element inserted into the guide hole. According to this, the restriction is a clearance formed between the valve body and the guide hole of the valve housing, which simplifies the valve structure.

[0011] The communication means may be a through hole that communicates between the inlet port and a space on the back side of the valve body. According to this, the structure of the communication means is simple.

[0012] The communication means may constitute a control pressure operated valve that controls communication between the inlet port and the space on the back side of the valve body, by including a through hole that communicates with the inlet port and the space on the back side of the valve body, a biasing means arranged in the through hole, and an actuating valve body that is biased in the valve closing direction by the biasing means. According to this, high primary pressure moves the operating valve element against the biasing force of the biasing means, opening the control pressure operated valve and establishing communication between the inlet port and the space behind the valve element through the through-hole. As a result, when the control pressure operated valve is open, the communication means can reduce the influence of the primary pressure acting on the valve element. This improves the accuracy of valve opening adjustment, particularly when the primary pressure becomes high and the pressure difference between the primary and secondary pressures becomes large. Furthermore, the control pressure operated valve controls the amount of refrigerant passing through as needed. This minimizes leakage of refrigerant at the primary pressure.

[0013] The valve may be of a normally closed configuration. According to this, the valve is suitable as an expansion valve, for example, to control refrigerant from a condenser to an evaporator. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a refrigeration cycle to which an expansion valve according to a first embodiment of the present invention is applied. [Figure 2] FIG. 2 is a cross-sectional view showing the expansion valve of the first embodiment in a closed state. [Figure 3]FIG. 2 is a cross-sectional view showing the expansion valve of the first embodiment in an opened state. [Figure 4] 2 is an enlarged cross-sectional view showing a valve chamber of the expansion valve of the first embodiment. FIG. [Figure 5] 2 is a cross-sectional view showing the pressure distribution in FIG. 1. In order to show the pressure distribution, cross sections of each member are omitted. [Figure 6] FIG. 6 is a cross-sectional view showing a state in which an expansion valve according to a second embodiment of the present invention is closed. [Figure 7] 10 is a diagram showing the pressure distribution when the valve and the control pressure operated valve of the expansion valve of Example 2 are closed, and in order to show the pressure distribution, cross sections of each member are omitted. [Figure 8] 10 is a diagram showing the pressure distribution in a state where the valve of Example 2 is closed and the control pressure actuated valve is open, and in order to show the pressure distribution, cross sections of each member are omitted. [Figure 9] FIG. 10 is an enlarged cross-sectional view showing a main part of an expansion valve according to a third embodiment of the present invention when the valve is closed. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing a main part of an expansion valve according to a third embodiment of the present invention when the valve is open. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve according to the present invention will be described below with reference to the following examples. [Example]

[0016] An expansion valve as a valve according to a first embodiment will be described with reference to Figures 1 to 5. Note that the embodiment will be described using an expansion valve as an example, but the invention is also applicable to other uses. In the following description, the left and right sides of Figure 2, as viewed from the front, will be referred to as the left and right sides of the expansion valve. Specifically, the left side of the page where the valve housing 10 is located will be referred to as the left side of the expansion valve, and the right side of the page where the solenoid 80 serving as the drive source is located will be referred to as the right side of the expansion valve.

[0017] As shown in FIG. 1, the expansion valve V1 of the present invention, together with a compressor C, an indoor heat exchanger H1, an outdoor heat exchanger H2, etc., constitutes a refrigeration cycle R used in an air conditioning system of an automobile or the like.

[0018] First, the refrigeration cycle R will be described. During heating, the refrigeration cycle R circulates a refrigerant through the compressor C, heat exchanger H1, expansion valve V1, and heat exchanger H2 in that order. The refrigerant becomes superheated vapor in the compressor C, exchanges heat with indoor air in the heat exchanger H1 to become a subcooled liquid, is reduced in pressure from a high primary pressure to a low secondary pressure in the expansion valve V1 to become wet vapor, and then exchanges heat with outdoor air in the heat exchanger H2 to become saturated vapor. The indoor air is heated by the heat exchange with the heat exchanger H1. That is, during heating, the heat exchanger H1 functions as a condenser, and the heat exchanger H2 functions as an evaporator.

[0019] During cooling, the refrigeration cycle R circulates the refrigerant through the compressor C, heat exchanger H2, expansion valve V1, and heat exchanger H1 in that order. The refrigerant becomes superheated vapor in the compressor C, exchanges heat with outdoor air in the heat exchanger H2 to become a subcooled liquid, is reduced in pressure from a high primary pressure to a low secondary pressure in the expansion valve V1 to become wet vapor, and then exchanges heat with indoor air in the heat exchanger H1 to become saturated vapor. The indoor air is cooled by the heat exchange with the heat exchanger H1. That is, during cooling, the heat exchanger H1 functions as an evaporator, and the heat exchanger H2 functions as a condenser.

[0020] In the following description, unless otherwise specified, it is assumed that the refrigeration cycle R is used for heating. Similarly, based on heating, the heat exchanger H1 will be referred to as the condenser H1, and the heat exchanger H2 will be referred to as the evaporator H2.

[0021] 2 and 3, expansion valve V1 is disposed between condenser H1 and evaporator H2. The current flowing through coil 86 of solenoid 80 is set based on the temperature difference between the refrigerant at the inlet and outlet sides of evaporator H2, and the valve opening of valve 50 in expansion valve V1 is adjusted. As a result, the pressure of the refrigerant passing through valve 50 is adjusted from high-pressure primary pressure P1 to relatively low-pressure secondary pressure P2, and the temperature is also adjusted from high to low. As a result, all of the refrigerant, which is a subcooled liquid sent from condenser H1, is adjusted to the dryness of wet steam that can transition to saturated vapor after passing through evaporator H2.

[0022] In this embodiment, the valve 50 is composed of a valve element 51 and a valve seat 40a. The valve seat 40a is formed on a cylindrical valve seat member 40 that is press-fitted and fixed into the recess 10a of the valve housing 10. The valve 50 opens and closes when a tapered surface 52a at the tip 52 of the valve element 51 moves toward and away from the valve seat 40a.

[0023] Next, the structure of the expansion valve V1 will be described. As shown in Figures 2 and 3, the expansion valve V1 is mainly composed of a valve housing 10, a valve element 51, and a solenoid 80. The valve housing 10 is made of a metal material or a resin material. The left end of the valve element 51 in the axial direction is located inside the valve housing 10. The solenoid 80 is connected to the valve housing 10 and is used to apply a driving force to the valve element 51.

[0024] 2 and 3, the valve element 51 has, in order from the left end in the axial direction, a tip portion 52, a small diameter portion 53, a large diameter portion 54, and a base portion 55. The valve element 51 also serves as a rod that is disposed to pass through the coil 86 of the solenoid 80.

[0025] 4, the tip portion 52 has a tip surface 52b and a tapered surface 52a, and is formed in a trapezoidal cross section. The tip surface 52b is flat and approximately circular. The tapered surface 52a extends axially rightward from the tip surface 52b at a constant cross section, and then gradually decreases in diameter as it extends axially rightward.

[0026] The small diameter portion 53 is a columnar body that extends axially rightward from the right end of the tip portion 52 with a constant cross section, and is formed with a smaller diameter than the through-flow passage 40b described later.

[0027] The large diameter portion 54 is a columnar body having a larger diameter than the small diameter portion 53, and its axial ends are gradually tapered in diameter.

[0028] The base portion 55 is a columnar body that extends axially rightward with a constant cross section from the axial right end of the large diameter portion 54. The base portion 55 has a smaller diameter than the large diameter portion 54.

[0029] As shown in Figures 2 and 3, an inlet port 11 and a recess 10a are formed on the inner diameter side of the left axial end of the valve housing 10. The inlet port 11 is recessed axially to the right and communicates with the condenser H1. The recess 10a is recessed further axially to the right at the radial center of the inlet port 11. An outlet port 12 that penetrates radially is also communicated with the recess 10a. The outlet port 12 is also communicated with the evaporator H2.

[0030] When the refrigeration cycle R is used for cooling, the outlet port 12 communicates with the heat exchanger H1, and the inlet port 11 communicates with the heat exchanger H2.

[0031] A valve seat member 40 is press-fitted into the recess 10a from the left in the axial direction, and is fixed integrally and substantially sealed.

[0032] As shown in Figure 4, the valve seat member 40 is formed with a through-flow passage 40b that penetrates in the axial direction. The through-flow passage 40b includes a tapered surface 40c and a peripheral wall surface 40d. The tapered surface 40c gradually reduces in diameter from the left end in the axial direction toward the right in the axial direction. The peripheral wall surface 40d extends approximately parallel to the axial direction. The boundary between the tapered surface 40c and the peripheral wall surface 40d forms the valve seat 40a.

[0033] Furthermore, the cross-sectional area RS1 of the portion of the tapered surface 52a of the tip portion 52 that seats on the valve seat 40a is approximately the same as the maximum cross-sectional area RS2 of the large diameter portion 54 of the valve body 51. In other words, the cross-sectional area RS1 is the effective pressure-receiving area of ​​the tip portion 52, and the maximum cross-sectional area RS2 is the effective pressure-receiving area of ​​the large diameter portion 54.

[0034] 2 and 3, a valve chamber 20 is defined inside the valve housing 10 by the recess 10a and the through-flow passage 40b in the valve seat member 40. Within the valve chamber 20, a part of the tip portion 52 of the valve element 51, a small diameter portion 53, and a part of the large diameter portion 54 are arranged so as to be able to reciprocate axially.

[0035] A guide hole 10b is formed in the inner peripheral surface of the valve housing 10, closer to the solenoid 80 than the valve seat 40a and the valve chamber 20, and the outer peripheral surface of the large diameter portion 54 of the valve element 51 can slide. A small clearance serving as a throttle 90 is formed between the inner peripheral surface of the guide hole 10b and the outer peripheral surface of the valve element 51 by separating them slightly in the radial direction. This allows the valve element 51 to move smoothly relative to the valve housing 10 in the axial direction.

[0036] The valve housing 10 also has a recess 10c formed on the inner diameter side of its right axial end, recessed axially leftward. A flange portion 82d of the center post 82 is press-fitted and fixed into the recess 10c from the right axial direction in a sealed state. The casing 81 is also fixed to the right end of the valve housing 10 from the right axial direction of the flange portion 82d. As a result, the valve housing 10, casing 81, and center post 82 are connected together. The open end of the guide hole 10b on the solenoid 80 side is formed on the inner diameter side of the bottom surface of the recess 10c of the valve housing 10.

[0037] Furthermore, a through hole 21 is formed in the valve housing 10 as communication means, extending axially between the bottoms of the recesses 10a, 10c at both axial ends. The through hole 21 has a constant cross section and communicates with the inlet port 11 and the space S within the solenoid 80.

[0038] As shown in Figures 2 and 3, the solenoid 80 is mainly composed of a casing 81, a center post 82, the valve element 51, a movable iron core 84, a coil spring 85, an exciting coil 86, and a sleeve 87. The casing 81 has an opening 81a that opens to the left in the axial direction. The roughly cylindrical center post 82 is inserted into the opening 81a of the casing 81 from the left in the axial direction and is disposed between the inner diameter side of the casing 81 and the inner diameter side of the valve housing 10. The valve element 51 is inserted through the center post 82 and is movable back and forth in the axial direction, and its left axial end is disposed within the valve housing 10. The right axial end of the valve element 51 is inserted into and fixed to the movable iron core 84. The coil spring 85 is disposed between the center post 82 and the movable iron core 84 and biases the movable iron core 84 axially rightward, which is the direction in which the valve 50 closes. The coil 86 is wound around the outside of the center post 82 via a bobbin. A sleeve 87 formed in a cylindrical shape with a bottom houses a part of the center post 82, the movable iron core 84, the coil spring 85, and a part of the valve body 51.

[0039] The center post 82 is formed from a rigid body that is a magnetic material such as iron or silicon steel, and includes a cylindrical portion 82b and a flange portion 82d. The cylindrical portion 82b is formed with an insertion hole 82c that extends in the axial direction and through which the valve body 51 is inserted. The flange portion 82d is formed in an annular shape that extends radially outward from the outer circumferential surface at the left axial end of the cylindrical portion 82b.

[0040] The space S within the solenoid 80 is mainly the space within the sleeve 87 located on the back side of the valve body 51 separated from the valve chamber 20, and includes the space within the recess 10c and the center post 82.

[0041] The space S also communicates with the valve chamber 20 on the downstream side of the valve seat 40a via a throttle 90.

[0042] As a result, the refrigerant at the primary pressure P1 also flows into the space S through the inlet port 11 and the through-hole 21, and can flow out from the outlet port 12 through the throttle 90 and the valve chamber 20.

[0043] Next, the operation of the expansion valve V1, mainly the opening and closing operation, will be described.

[0044] First, the non-energized state of the expansion valve V1 will be described. As shown in FIG. 2, when the expansion valve V1 is in the non-energized state, the movable iron core 84 is biased by the biasing force (F sp ) is pressed axially rightward. As a result, the valve element 51 is pressed axially rightward, and the tapered surface 52a at the tip 52 of the valve element 51 is seated on the valve seat 40a. In other words, the valve 50 is closed.

[0045] When closed, the valve 50 does not allow refrigerant to pass through. Meanwhile, the downstream side of the valve seat 40a in the valve chest 20 is in communication with the evaporator H2, which is at a relatively low pressure, through the outlet port 12. Therefore, a fluid at a secondary pressure P2, which is relatively lower than the primary pressure P1, flows into the downstream side of the valve seat 40a in the valve chest 20.

[0046] As shown in FIG. 3, when the expansion valve V1 is energized (i.e., during normal control, or so-called duty control), an electromagnetic force (F sol ) is the biasing force (F sp ) exceeds (F sol >F sp ), the movable core 84 is attracted toward the center post 82, i.e., to the left in the axial direction. Also, the valve element 51 fixed to the movable core 84 moves axially leftward together with the movable core 84. As a result, the tapered surface 52a at the tip 52 of the valve element 51 moves away from the valve seat 40a, and the valve 50 opens.

[0047] When open, the valve 50 expands the refrigerant passing through it. Accordingly, when open, the valve 50 reduces the refrigerant pressure from primary pressure P1 to secondary pressure P2. That is, fluid at secondary pressure P2 flows into the valve chamber 20 downstream of the valve seat 40a.

[0048] Furthermore, the minute gap that forms the throttle 90 is narrower than the maximum opening area of ​​the valve 50. Therefore, during normal control, the refrigerant flowing into the space S is maintained at a pressure close to the primary pressure P1.

[0049] Next, the force F acting on the valve body 51 rod As shown by the fine dotted pattern in Fig. 5, a fluid at a primary pressure P1 flows into the inlet port 11, the through hole 21, the upstream side of the valve seat 40a in the valve chest 20, and the space S. As shown by the coarse dotted pattern in Fig. 5, a fluid at a secondary pressure P2 flows into the downstream side of the valve seat 40a in the valve chest 20 and the outlet port 12. Note that although the valve 50 is shown closed in Fig. 5, the same applies when it is open. For this reason, the valve 50 is not shown when open.

[0050] As a result, the biasing force (F sp ), the driving force of the solenoid 80 acting in the valve opening direction when energized (F sol ), primary and secondary refrigerant pressures P1 and P2 act on the valve body 51 in the valve closing and opening directions, respectively.

[0051] More specifically, the force acting on the valve element 51 from the refrigerant is a force F due to the primary pressure P1, with the valve closing direction being positive and the valve opening direction being negative. p1 = P1 × (RS1-RS2) = Force F due to secondary pressure P2 p2 =P2×(RS1-RS2) is subtracted.

[0052] From these facts, the valve closing direction is positive and the valve opening direction is negative, and the force F acts on the valve body 51. rod =F sp +F p1 -Fp2 As mentioned above, the cross-sectional areas RS1 and RS2 are approximately the same, so the force F p1 ,F p2 Therefore, the valve body 51 is mainly subjected to the biasing force (F sp ) and the driving force of solenoid 80 (F sol ) will act on (F rod =F sp +F sol ).

[0053] As described above, in a state where the inlet port 11 and the space S in the solenoid 80 are in communication with each other through the through hole 21, the refrigerant at the primary pressure P1 that flows from the condenser H1 into the inlet port 11 is supplied to the space S. As a result, the force F due to the primary pressure P1 p1 and the force F due to the secondary pressure P2 p2 and are both zero, the through hole 21 can reduce the effect of the force of the refrigerant at the primary pressure acting on the valve body 51. Therefore, the expansion valve V1 has improved accuracy in adjusting the valve opening degree of the valve 50.

[0054] Also, the driving force of the solenoid 80 (F sol ) is the biasing force (F sp ), the valve 50 is opened. Therefore, by supplying the refrigerant at the primary pressure to the space S on the back side of the valve body 51 through the through-hole 21, it is possible to reduce the driving force of the solenoid 80 when the valve 50 is near the closed state, i.e., when the valve 50 is opened from the closed state, and when the valve 50 is kept slightly open.

[0055] Still, in this embodiment, the cross-sectional areas RS1 and RS2 have been described as being substantially the same, but the present invention is not limited to this. The cross-sectional area RS1 may be larger than the cross-sectional area RS2 (RS1 > RS2), or the cross-sectional area RS1 may be smaller than the cross-sectional area RS2 (RS1 < RS2). Even in such a configuration, the forces of the overlapping area integrals are canceled out, and only the force of the area integral of the difference between the cross-sectional areas RS1 and RS2 acts on the valve body 51. Therefore, the refrigerant at the primary pressure supplied to the space S on the back side of the valve body 51 can have its influence reduced by the pressure of the refrigerant acting on the valve body 51.

[0056] Also, in this embodiment, the pressure of the refrigerant in the space S has been described as being the primary pressure, but the present invention is not limited to this. Any pressure close to the primary pressure may be used.

[0057] Also, the throttle 90 is the clearance formed between the valve body 51 and the guide hole 10b of the valve housing 10. As a result, the structure of the expansion valve V1 is simple.

[0058] Also, the communication means of this embodiment is the through-hole 21 that communicates the inlet port 11 and the space S. Therefore, the structure of the communication means is simple.

[0059] Also, the expansion valve V1 has a normally closed structure in which the valve 50 is closed in the non-energized state. Therefore, the expansion valve V1 can maintain the pressure on the condenser H1 side at the primary pressure P1 when non-energized, that is, even when the refrigeration cycle R is stopped, the refrigerant on the condenser H1 side can be maintained as a subcooled liquid. As a result, even immediately after the refrigeration cycle R is started, all the refrigerant in the evaporator H2 can be transitioned to saturated vapor and heated in the same manner as during normal control, so the expansion valve V1 is suitable as an expansion valve.

[0060] Furthermore, the direction in which the refrigerant at the primary pressure P1 acts on the tip 52 of the valve element 51 and the valve closing direction of the expansion valve V1 are the same. Therefore, even if the primary pressure P1 suddenly increases, the pressure difference between the pressure in the inlet port 11 and the pressure in the space S acts on the valve element 51 in the valve closing direction. This makes it possible for the expansion valve V1 to prevent the valve element 51 from being unintentionally opened. [Example]

[0061] An expansion valve according to a second embodiment will be described with reference to Figures 6 to 8. Note that a description of the same configuration as in the first embodiment will be omitted. Note that Figures 6 and 7 show a state in which the primary pressure P1 in the inlet port 11 is low, and Figure 8 shows a state in which the primary pressure P1 in the inlet port 11 is high.

[0062] 6 to 8, in this embodiment, the through hole 210 in the valve housing 10 of the expansion valve V2 is composed of a small diameter hole portion 22 and a large diameter hole portion 23. The left axial end of the small diameter hole portion 22 communicates with the inlet port 11. The large diameter hole portion 23 is continuous with the right axial end of the small diameter hole portion 22 and has a larger diameter than the small diameter hole portion 22.

[0063] An actuating valve element 31 and a return spring 32 serving as a biasing means are disposed in the large diameter hole portion 23. The actuating valve element 31 is ball-shaped. The right axial end of the return spring 32 is fixed to the center post 82, and the left axial end of the return spring 32 abuts against the actuating valve element 31. The actuating valve element 31 and the return spring 32 constitute a control pressure actuated valve 30 that controls communication between the inlet port 11 and the space S within the solenoid 80.

[0064] 7, when the primary pressure P1 in the inlet port 11 is low, the operating valve element 31 is urged axially leftward by the return spring 32 and seats on the open end of the small diameter hole portion 22 of the through hole 210, thereby closing the control pressure operated valve 30. As a result, the inlet port 11 and the space S are not in communication with each other.

[0065] At this time, as shown by the fine dot pattern in FIG. 7, the primary pressure P1 (F p11 ) acts on the return spring 32 in the axial left direction, and the biasing force (F SP ) and the pressure of the refrigerant in space S (F p12 ) is acting (F p11 <F SP +F p12 ).

[0066] 8, when the primary pressure P1 in the inlet port 11 is high, the operating valve element 31 moves axially rightward against the biasing force of the return spring 32 and the pressure of the refrigerant in the space S. This opens the control pressure operated valve 30. As a result, the inlet port 11 and the space S are in communication.

[0067] At this time, the operating valve body 31 is subjected to the biasing force (F SP ) and the pressure of the refrigerant in space S (F p12 ) in the inlet port 11 exceeds the primary pressure P1 (F p11 ) acts towards the right in the axial direction (F p11 >F SP +F p12 ).

[0068] When the control pressure operated valve 30 is opened and the inlet port 11 and space S are in communication as in the state shown in Figure 8, the pressure difference between the refrigerant in the inlet port 11 and space S becomes small, as shown by the fine dot pattern in Figure 8. In this way, when the control pressure operated valve 30 is open, the influence of the primary pressure P1 of the refrigerant in the inlet port 11 and the valve chamber 20 on the valve element 51 becomes smaller. Therefore, when the control pressure operated valve 30 is open, the through hole 210 allows the valve element 51 to move smoothly axially leftward (valve closing direction).

[0069] In this way, the primary pressure P1 in the high inlet port 11 is increased by the biasing force (F SP), moving the operating valve element 31 against the pressure P1, opening the control pressure operated valve 30 and communicating the inlet port 11 with the space S inside the solenoid 80 through the through hole 210. As a result, when the control pressure operated valve 30 is open, the through hole 210 can reduce the influence of the refrigerant pressure acting on the valve element 51. Therefore, particularly when the primary pressure P1 becomes high and the pressure difference between the primary pressure P1 and the secondary pressure P2 becomes large, the expansion valve V2 improves the accuracy of adjusting the valve opening of the valve 50. In addition, the control pressure operated valve 30 controls the amount of refrigerant passing through as needed. Therefore, the amount of refrigerant leaking from the primary pressure P1 is small.

[0070] Furthermore, the refrigerant in the space S can be gently released to the outlet port 12 through the minute gap between the inner circumferential surface of the guide hole 10b and the outer circumferential surface of the valve body 51, i.e., through the orifice 90. This allows the control pressure operated valve 30 to maintain an open state. Specifically, the orifice 90 can prevent the control pressure operated valve 30 from immediately closing due to a sudden rise in refrigerant pressure in the space S. [Example]

[0071] An expansion valve according to a third embodiment will be described with reference to Figures 9 and 10. Note that a description of the same configuration as in the first and second embodiments will be omitted.

[0072] 9 and 10, in this embodiment, two annular grooves 56, 57 are formed in the outer peripheral surface of the large diameter portion 354 of the valve body 51 of the expansion valve V3. Each of the annular grooves 56, 57 is an annular groove that is open in the outer radial direction and recessed in the inner radial direction, and each of the bottom surfaces thereof is curved in a semicircular arc. Note that the bottom surfaces of the annular grooves 56, 57 may be curved in a shape other than a semicircular arc, or may be V-shaped, U-shaped, or the like, and may be modified as appropriate.

[0073] Additionally, annular groove 56 is located axially to the left of annular groove 57. These annular grooves 56, 57 are located more centrally than both axial edges of guide hole 10b in valve housing 10, both when valve 50 is closed and when it is open. In other words, the locations of large diameter portion 354 where annular grooves 56, 57 are formed and their vicinity are configured to reciprocate with a substantially constant clearance from guide hole 10b.

[0074] When the refrigerant flows axially through the orifice 390, a vortex of the refrigerant with its center in the circumferential direction is generated in the annular grooves 56, 57. This vortex aligns the axis of the large diameter portion 354 so that it coincides with the axis of the guide hole 10b. This reduces the driving force required to move the valve element 51.

[0075] Furthermore, the generation of vortices in the annular grooves 56, 57 makes it difficult for the refrigerant to move relatively in the axial direction within the throttle 90. Therefore, the annular grooves 56, 57 can prevent excessive leakage of the refrigerant from the space S to the outlet port 12.

[0076] Furthermore, the annular grooves 56, 57 of the large diameter portion 354 face the guide hole 10b throughout the stroke range of the valve body 51. Therefore, the annular grooves 56, 57 of the large diameter portion 354 can stably align the valve body 51 and prevent excessive leakage of refrigerant from the space S to the outlet port 12.

[0077] The number of annular grooves may be one or three or more. Furthermore, the annular groove may move axially outward from the guide hole 10b during reciprocation.

[0078] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0079] For example, in the above embodiment, an example was given in which the valve opening degree is adjusted based on the temperature difference between the refrigerant on the inlet side and the outlet side of the evaporator, but this is not limited to this, and the valve opening degree may be adjusted based on the temperature or pressure of the refrigerant before or after passing through the condenser, or the temperature or pressure of the refrigerant before or after passing through the evaporator, and this may be changed as appropriate.

[0080] In the above embodiment, the expansion valve is exemplified as a valve closing direction in which the direction in which the refrigerant at the primary pressure acts on the tip of the valve disc is the same as the valve closing direction, but this is not limited thereto. The direction in which the refrigerant at the primary pressure acts on the tip of the valve disc may be the same as the valve opening direction. In such a configuration, the valve disc may be in the form of a column with a constant cross section. In other words, the shape of the valve disc may be changed as appropriate.

[0081] Furthermore, in the above embodiment, the inlet port and the space on the back side of the valve body are connected by a through hole, but this is not limiting. The inlet port, the back side of the valve body, and the space may be connected by a large opening, and a throttle member such as an orifice may be provided in the opening.

[0082] In addition, in the above embodiment, an example was given of a form in which the control pressure operated valve is composed of a through hole, an operating valve body, and a return spring, but this is not limited to this, and the form may also be such that the center post is operated by the electromagnetic force of the solenoid to connect the inlet port to the space, or a member other than the center post may be operated by the electromagnetic force of the solenoid to connect the inlet port to the space.

[0083] In the above embodiment, the valve element is described as also serving as a rod that passes through the coil of the solenoid, but this is not limiting, and the valve element and the rod may be separate bodies.

[0084] In addition, in the above embodiment, the valve seat member having the valve seat and the valve housing having the guide hole are described as being provided separately, but this is not limited to this, and the valve seat and the guide hole may be integrally formed on the inner peripheral surface of the valve housing.

[0085] Furthermore, the guide portion is not limited to being formed on the valve housing, but may be formed, for example, on a part of the insertion hole of the center post. [Explanation of symbols]

[0086] 10 Valve housing 10b Guide hole 11 Inlet port 12 Exit Port 20 Valve chamber 21 Through hole (communication means) 30 Control pressure operated valve (communication means) 31 Operating valve body (communication means) 32 Return spring (biasing means, communication means) 40a Valve seat 50 valves 51 Valve body 80 Solenoid (drive source) 85 coil spring (spring) 90 aperture 210 Through hole (communication means) C Compressor H1 Heat exchanger (condenser for heating, evaporator for cooling) H2 heat exchanger (evaporator during heating, condenser during cooling) P1 Primary pressure P2 Secondary pressure R refrigeration cycle RS1 cross-sectional area RS2 cross section S space V1, V2 expansion valve (valve)

Claims

1. a valve housing having an inlet port and an outlet port formed therein; a valve body that is driven to open and close by a solenoid; a valve seat on which the valve body is seated; a spring that biases the valve body in a direction opposite to the driving direction of the solenoid, a valve in which a communication passage between the inlet port and the outlet port is opened and closed by moving the valve body and the valve seat toward and away from each other, and an opening degree of the communication passage is adjustable by duty control according to a drive amount of the solenoid, The valve is provided with a communication means that allows communication between the inlet port and a space on the solenoid side of the valve seat in the valve body.

2. 2. The valve according to claim 1, wherein a space of the valve body on the solenoid side of the valve seat is connected to the outlet port via a throttle.

3. 3. The valve according to claim 2, wherein the throttle is formed by a guide hole in the valve housing and the valve element inserted into the guide hole.

4. 4. The valve according to claim 1, wherein the communication means is a through hole that communicates the inlet port with a space in the valve body that is closer to the solenoid than the valve seat.

5. 4. The valve according to claim 1, wherein the communication means comprises a through hole communicating with the inlet port and a space in the valve body on the solenoid side of the valve seat, a biasing means disposed in the through hole, and an actuating valve body biased in a valve closing direction by the biasing means, thereby constituting a control pressure actuated valve that controls communication between the inlet port and a space in the valve body on the solenoid side of the valve seat.

6. 6. The valve according to claim 1, wherein the valve has a normally closed structure.

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