Expansion valve

Abstract

To provide an expansion valve which can be suppressed in enlargement, and furthermore can secure a valve closed state.SOLUTION: An expansion valve includes: a power element 8 including a diaphragm 83 for partitioning a first space UC disposed in a valve main body 2 and enclosed with working fluid and a second space LC communicable with a pressure equalization passage; an energization device 4 for energizing a valve body 3 toward a valve seat 20; an operation rod 5 disposed in the valve main body and transmitting displacement of the diaphragm to the valve body; and a movable valve drive device for displacing a movable valve in the valve main body. When the movable valve drive device displaces the movable valve to a first position, the second space and a high-pressure chamber are communicated, and communication between the second space and the pressure equalization passage is blocked, and when the movable valve is displaced to a second position, the second space and the pressure equalization passage are communicated, and communication between the second space and the high-pressure chamber pressure is blocked.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an expansion valve. [Background technology]

[0002] As one type of expansion valve, an expansion valve equipped with a solenoid valve is known. This type of expansion valve is applied to, for example, a refrigeration cycle having a plurality of evaporators connected in parallel, and has a function of controlling the degree of superheat of the refrigerant on the outlet side of the evaporators as well as a function of shutting off the circuit in the refrigeration cycle.

[0003] Patent Document 1 discloses a solenoid valve-integrated expansion valve in which a solenoid valve is disposed on a refrigerant supply path from a condenser. With this solenoid valve-integrated expansion valve, the expansion valve can be forcibly closed by opening the solenoid valve to open the refrigerant supply path and closing the solenoid valve to close the refrigerant supply path.

[0004] Patent Document 2 discloses a solenoid valve-integrated expansion valve in which refrigerant that has passed through a solenoid valve is supplied to a valve chamber. With this solenoid valve-integrated expansion valve, refrigerant is supplied to the valve chamber by opening the solenoid valve, and the supply of refrigerant to the valve chamber can be cut off by closing the solenoid valve, forcing the expansion valve into a closed state. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-42081 A [Patent Document 2] JP 2006-266543 A Summary of the Invention [Problem to be solved by the invention]

[0006] According to the expansion valves of Patent Documents 1 and 2, the solenoid valve and the expansion valve are connected in series, so the refrigerant always passes through the orifice of the solenoid valve before being discharged from the solenoid valve-integrated expansion valve. For this reason, in order to increase the capacity of the solenoid valve-integrated expansion valve, it is necessary to incorporate a solenoid valve with a large-diameter orifice, which leads to an increase in the size of the solenoid valve-integrated expansion valve.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide an expansion valve that can maintain a closed state at will while minimizing the increase in size. [Means for solving the problem]

[0008] The expansion valve of the present invention is a valve body including a valve chamber, a valve seat, a high pressure chamber to which a refrigerant having a first pressure is supplied, and a pressure equalizing passage to which a refrigerant having a second pressure lower than the first pressure is supplied; a valve body disposed in the valve chamber; a power element provided in the valve body and including a diaphragm for separating a first space in which a working fluid is sealed and a second space capable of communicating with the pressure equalizing path; a biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and configured to transmit the displacement of the diaphragm to the valve element; a movable valve drive device for displacing a movable valve within the valve body, The movable valve drive device is characterized in that, when the movable valve is displaced to a first position, the second space is communicated with the high pressure chamber and communication between the second space and the pressure equalizing path is blocked, and when the movable valve is displaced to a second position, the second space is communicated with the pressure equalizing path and communication between the second space and the high pressure chamber is blocked. Effect of the Invention

[0009] According to the present invention, it is possible to provide an expansion valve that can secure a closed state at will while suppressing an increase in size. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example in which an expansion valve according to the present embodiment is applied to a refrigeration cycle. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the external pressure equalizing expansion valve according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing the AA section of FIG. 1 as viewed from the side. [Figure 4] FIG. 4 is a cross-sectional view showing the cross section BB of FIG. 1 in a plan view. [Diagram 5] FIG. 5 is a cross-sectional view showing a cross section taken along line CC in FIG. 1 as viewed in plan. [Figure 6] FIG. 6 is a cross-sectional view showing the cross section DD of FIG. 1 in a plan view. [Figure 7] FIG. 7 is a cross-sectional view similar to FIG. 3 of an expansion valve according to a modified example, showing the on state of the solenoid valve. [Figure 8] FIG. 8 is a cross-sectional view similar to FIG. 3 of an expansion valve according to a modified example, showing the solenoid valve in an off state. [Figure 9] FIG. 9 is a vertical cross-sectional view of the expansion valve according to the second embodiment, showing the on state of the solenoid valve. [Figure 10] FIG. 10 is a vertical cross-sectional view of the expansion valve according to the second embodiment, showing the off state of the solenoid valve. [Figure 11] FIG. 11 is a cross-sectional view showing the E-E cross section of FIG. 9 in a plan view. [Figure 12] FIG. 12 is a cross-sectional view showing the FF cross section of FIG. 9 in a plan view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) The structure of the expansion valve 1 according to the first embodiment will be described below with reference to the drawings.

[0012] First, the outline of the refrigeration system including the expansion valve in the first embodiment will be described. FIG. 1 is a diagram schematically showing an example in which the expansion valve 1 in this embodiment is applied to the refrigeration cycle 100.

[0013] In FIG. 1, the expansion valve 1, the compressor 101, the condenser 102, and the evaporator 103 are connected in a closed circuit via pipes to constitute a refrigeration cycle. The upper space of the power element 8 (described later) of the expansion valve 1 is connected to the temperature sensing cylinder 87 via the capillary tube 81.

[0014] The first flow path 21 (described later) of the expansion valve 1 is connected to the primary pipe H1 on the condenser 102 side, the second flow path 22 (described later) of the expansion valve 1 is connected to the secondary pipe H2 on the evaporator 103 side, and the outlet side pipe H3 of the evaporator 103 is connected to the compressor 101. The compressor 101 and the condenser 102 are connected by a high-pressure pipe H4. Also, the equalizing pipe H5 connects the outlet side pipe H3 of the evaporator 103 and the equalizing path 23 (described later) of the expansion valve 1.

[0015] The refrigerant compressed by the compressor 101 is supplied to the condenser 102 through the high-pressure pipe H4, condensed and liquefied, and supplied to the expansion valve 1 through the high-pressure primary pipe H1 in the state of the first pressure P1. The expansion valve 1 reduces the pressure (expands) the supplied refrigerant and supplies it to the evaporator 103 through the secondary pipe H2. Then, the evaporator 103 evaporates and vaporizes the refrigerant, and the vaporized refrigerant returns to the compressor 101 through the outlet side pipe H3 and is compressed again by the compressor 101. A temperature sensing cylinder 87 is attached to the outlet side pipe H3 of the evaporator 103. The second pressure P2 (<P1) in the outlet side pipe H3 of the evaporator 103 is transmitted to the lower space of the power element 8 of the expansion valve 1 through the equalizing pipe H5 and the equalizing path 23.

[0016] Fig. 2 is a vertical cross-sectional view of the external pressure equalizing expansion valve 1 according to the first embodiment. Fig. 3 is a cross-sectional view showing the AA section in Fig. 1 as viewed from the side, Fig. 4 is a cross-sectional view showing the BB section in Fig. 1 as viewed from the top, Fig. 5 is a cross-sectional view showing the CC section in Fig. 1 as viewed from the top, and Fig. 6 is a cross-sectional view showing the DD section in Fig. 1 as viewed from the top. Here, the direction from the valve body 3 toward the power element 8 is defined as an upward direction, and conversely, the direction from the power element 8 toward the valve body 3 is defined as a downward direction.

[0017] 2, the expansion valve 1 mainly comprises a valve body 2 having a valve chamber VS, a valve element 3, a biasing device 4, an actuating rod 5, and a power element 8. The center line of the valve element 3 is defined as an axis L of the expansion valve 1.

[0018] In addition to the valve chamber VS, the valve body 2 includes a first flow path 21 to which the pipe H1 is connected, a second flow path 22 to which the pipe H2 is connected, an intermediate chamber 221, and a pressure equalizing path 23 (FIG. 3) to which the pipe H5 is connected. The first flow path 21 is a supply-side flow path, and a refrigerant is supplied to the valve chamber VS via the supply-side flow path. The second flow path 22 is a discharge-side flow path, and the fluid in the valve chamber VS is discharged to the outside of the expansion valve via the orifice hole 27, the intermediate chamber 221, and the discharge-side flow path.

[0019] The first flow passage 21 and the valve chamber VS communicate with each other through a connection passage 21a having a smaller diameter than the first flow passage 21. The valve chamber VS and the intermediate chamber 221 communicate with each other through the valve seat 20 and the orifice hole 27. The inner periphery of the lower end of the orifice hole 27 constitutes the valve seat 20.

[0020] The actuating rod insertion hole 28 formed above the intermediate chamber 221 opens to the bottom of a recess 29 formed in the upper end of the valve body 2. The recess 29 has a large diameter portion 29a on the upper side and a small diameter portion 29b on the lower side.

[0021] The valve disc 3 is disposed in the valve chamber VS. The valve disc 3 is composed of a valve disc portion 3a having tapered upper and lower ends and a guide portion 3b connected together. The upper and lower ends of the guide portion 3b abut against the inner circumference of the valve chamber VS, allowing the valve disc 3 to slide in the direction of the axis L while maintaining its posture.

[0022] When the tapered portion of the head of the valve element 3 is seated on the valve seat 20, the flow of refrigerant passing through the orifice hole is restricted. This state is called a non-communicating state. However, even when the valve element 3 is seated on the valve seat 20, a restricted amount of refrigerant may flow. On the other hand, when the valve element 3 is separated from the valve seat 20, the flow of refrigerant passing through the orifice hole increases. This state is called a communicating state.

[0023] The biasing device 4 has a coil spring 41 made of a wire rod with a circular cross section wound in a spiral shape, a retaining plate 42 with a bowl-shaped recess on the upper surface that supports the lower end of the valve body 3a, and a spring receiving member 44. The cap 45 is attached to the valve body 2 as described below to protect the spring receiving member 44 and the like.

[0024] The spring receiving member 44 is fixed to the lower end of the valve body 2 by screwing a male thread formed on the outer periphery into a female thread formed on the lower end of the valve body 2 .

[0025] The upper end of the coil spring 41 abuts against the lower surface of the retaining plate 42 near its outer periphery, and the lower end of the coil spring 41 is held by a spring receiving member 44, whereby the coil spring 41 biases the two in a direction separating them.

[0026] After the coil spring 41 is attached, the cap 45 is attached to the lower end of the valve body 2 by screw fastening or the like, and shields and protects the spring receiving member 44.

[0027] The lower end of the actuating rod 5 abuts against the upper end of the valve disc 3. The actuating rod 5 is slidably fitted and guided in the actuating rod insertion hole 28 along the axis L, and can press the valve disc 3 in the valve opening direction against the biasing force of the biasing device 4. When the actuating rod 5 moves downward, the valve disc 3 moves away from the valve seat 20, and the expansion valve 1 is in the open state.

[0028] Next, a description will be given of the power element 8. The power element 8 has an upper cover member 82, a diaphragm 83, a receiving member 86, and a stopper member 84.

[0029] The top cover member 82 is formed, for example, by press-molding a metal plate. The top cover member 82 has a flattened dome shape with a raised center, and an opening 82a is formed through the center. The lower end of the capillary tube 81 is fixed to the opening 82a by brazing or welding.

[0030] The receiving member 86 facing the upper cover member 82 is formed, for example, by press-molding a metal plate. The receiving member 86 has an annular lower flange portion 86a and a cylindrical portion 86b that is connected to the inner periphery of the lower flange portion 86a and faces downward. A female thread 86c is formed on the inner periphery of the cylindrical portion 86b.

[0031] Diaphragm 83, which is disposed between upper cover member 82 and receiving member 86, is made of a thin, flexible metal (e.g., SUS) plate material, and has an outer diameter approximately the same as the outer diameters of upper cover member 82 and receiving member 86. Diaphragm 83 has a concentrically uneven shape formed thereon, and has a flexible structure.

[0032] The stopper member 84 is made up of a disk portion 84a and a cylindrical portion 84b connected together.

[0033] A hollow cylindrical seal holder 87 is press-fitted into the large diameter portion 29a of the recess 29 of the valve body 2, and the cylindrical portion 84b is slidably fitted into its inner periphery. The upper end of the actuating rod 5 is fitted into the small diameter portion 29b of the recess 29 and can abut against the lower end of the cylindrical portion 84b. An O-ring OR is disposed between the outer periphery of the actuating rod 5 and the inner periphery of the small diameter portion 29b to provide a seal between the two. The O-ring OR is held between the step between the actuating rod insertion hole 28 and the recess 29, and the lower end of the seal holder 87.

[0034] A pressure adjustment passage 222 extends parallel to the axis L so as to partially overlap with the large diameter portion 29a (see FIGS. 2 and 4). The upper end of the pressure adjustment passage 222 opens at the upper end of the valve body 2 toward the disk portion 84a, and the lower end of the pressure adjustment passage 222 communicates with a side opening 314 as described below. The pressure adjustment passage 222 communicates with a lower space LC of the diaphragm 83 through a gap between the disk portion 84a and the upper end of the valve body 2.

[0035] (Solenoid valve mounting structure) In Fig. 3, which is a cross section parallel to the axis L, the center line of the pressure adjustment passage 222 is defined as the axis O1. The side opening 314 formed in the valve body 2 has a large opening 314a, a crimped groove portion 314b, a small opening 314c having a smaller diameter than the large opening 314a, a bypass passage 314d having a smaller diameter than the small opening 314c, and a communication hole 314e having a smaller diameter than the bypass passage 314d, along an axis O2 perpendicular to the axis O1. The communication hole 314e communicates with the pressure equalizing passage 23. The lower end of the pressure adjustment passage 222 communicates with the inner circumference of the small opening 314c. The bottom of the large opening 314a communicates with the valve chamber VS (Fig. 2) through an inlet hole 314h.

[0036] The valve seat member 312 is disposed in the small opening 314c. The valve seat member 312 is formed by connecting a cylindrical shaft portion 312g and a circular flange portion (also simply referred to as a flange portion) 312e. One end (the back end) of the valve seat member 312 abuts against a step portion between the small opening 314c and the bypass passage 314d, and the circular flange portion 312e formed on the other end is engaged with the crimp groove portion 314b. The valve seat member 312 is fixed to the small opening 314c by crimping the cylindrical crimp portion 312i of the valve body 2 radially inward, thereby forming a part of the valve body 2. However, the attachment of the valve seat member 312 is not limited to the above, and the valve seat member 312 may be attached to the valve body 2 by, for example, providing a male thread on the outer periphery of the valve seat member 312 and a female thread on the small opening 314c, and screwing the male thread and the female thread. An O-ring OR is provided between the circular flange portion 312e and the valve body 2 to provide a seal therebetween.

[0037] The valve seat member 312 further has a circular through hole 312a extending along the axis O2, a circumferential groove 312b formed around the entire circumference near the end of the cylindrical shaft portion 312g, and a radial hole 312c radially connecting the circular through hole 312a and the circumferential groove 312b (through the side wall). The circumferential groove 312b communicates with the pressure adjustment passage 222. Here, the circular through hole 312a constitutes a switching hole.

[0038] The cylindrical valve shaft member 313 has a long shaft portion (also simply referred to as a shaft portion) 313a inserted so as to penetrate through the through hole 312a of the valve seat member 312, a flange portion 313b having a diameter larger than that of the through hole 312a, and a short shaft portion 313c. The surface of the flange portion 313b facing the through hole 312a is a tapered surface, improving the sealing performance when it abuts against the through hole 312a. There is a gap between the outer periphery of the long shaft portion 313a and the inner periphery of the through hole 312a through which the refrigerant can pass, and the valve shaft member 313 constitutes a movable valve together with the ball 136 of the solenoid valve EV, and is movable relative to the valve seat member 312 in the direction of the axis O2 between a first position and a second position. Although details will be described later, the first position of the movable valve is a position where the lower space LC (pressure adjustment path 222) and the high pressure chamber HS communicate with each other and where the communication between the lower space LC (pressure adjustment path 222) and the pressure equalizing path 23 is blocked. The second position of the movable valve is a position where the lower space LC (pressure adjustment path 222) and the pressure equalizing path 23 communicate with each other and where the communication between the lower space LC (pressure adjustment path 222) and the high pressure chamber HS is blocked.

[0039] A compression spring 316 is disposed around the short shaft portion 313c between the bottom of the bypass passage 314d and the opposing surface of the flange portion 313b, and biases the valve shaft member 313 toward the valve seat member 312 with respect to the bottom of the bypass passage 314d.

[0040] (Solenoid valve) The solenoid valve EV includes an annular base 120, a pipe 141 that is disposed on the inner periphery of a coil and a yoke (not shown) and extends in the direction of the axis O2, a plunger 135 that is disposed on the inner periphery of the pipe 141 so as to be slidable in the direction of the axis O2, and an attractor 140 that is fixed to the inner periphery of the end of the pipe 141. When the coil (not shown) is powered (powered state or on state), the attractor 140 attracts the plunger 135 by magnetic force, but when the coil (not shown) is not powered (non-powered state or off state), the attractor 140 loses the magnetic force that attracts the plunger 135. The solenoid valve EV constitutes a movable valve drive device.

[0041] An end of the pipe 141 is fixed to the inner periphery of the base 120 by press-fitting or brazing, and a male thread formed on the outer periphery of the base 120 is screwed into a female thread formed on the inner periphery of the large opening 314a of the valve body 2, thereby fixing the base 120 to the valve body 2. As a result, a high pressure chamber HS is formed between the base 120 and the large opening 314a. The high pressure chamber HS communicates with the inlet hole 314h and is also capable of communicating with the circular through hole 312a of the valve seat member 312.

[0042] The cylindrical plunger 135 is made of a magnetic material and is formed by connecting an enlarged diameter cylinder portion 135a and a reduced diameter cylinder portion 135b. A circular recess 135c is formed at the inner end of the reduced diameter cylinder portion 135b, and a ball 136 is fixed to the circular recess 135c by caulking so that a part of the outer surface is exposed. The ball attached to the plunger 135 is not limited to a metal ball. For example, a member made of rubber or synthetic resin may be attached to the plunger 135 instead of a ball. In this embodiment, the ball 136, which constitutes a movable valve together with the valve shaft member 313, is displaced to a first position in the on state and is displaced to a second position in the off state.

[0043] A communication passage 135d is formed to extend from the outer periphery of the reduced diameter cylindrical portion 135b toward the outer end of the plunger 135. A compression coil spring 137 is disposed in the communication passage 135d and compressed between the plunger 135 and the attractor 140, and biases the plunger 135 in a direction away from the attractor 140.

[0044] (Expansion valve operation) An example of the operation of the expansion valve 1 will be described with reference to the drawings. The refrigerant pressurized by the compressor 101 is supplied to the condenser 102 via the high-pressure pipe H4, where it is condensed and liquefied, and then sent to the expansion valve 1 via the primary pipe H1. The refrigerant adiabatically expanded by the expansion valve 1 is sent to the evaporator 103 via the secondary pipe H2, where it is heat exchanged with the air flowing around it. Thereafter, the refrigerant is returned from the evaporator 103 to the compressor 101 via the outlet pipe H3.

[0045] At this time, the pressure of the refrigerant in the outlet pipe H3 is transmitted to the pressure equalizing path 23 of the expansion valve 1 via the pressure equalizing pipe H5, and is further transmitted to the lower space (second space) LC of the power element 8. Meanwhile, as the temperature of the refrigerant in the outlet pipe H3 is transmitted to the temperature sensing tube 87, the gas-liquid state and pressure of the gas (working fluid) in the temperature sensing tube 87 change, and are transmitted to the upper space (first space) UC of the power element 8 via the capillary tube 81. When the solenoid valve EV is in the off state, the diaphragm 83 is displaced vertically due to the pressure difference between the upper space UC and the lower space LC.

[0046] In the expansion valve 1, high-pressure refrigerant from a condenser 102 is supplied to a valve chamber VS through a first flow passage 21.

[0047] Here, it is assumed that the solenoid valve EV is in an OFF state. In this case, since the coil (not shown) does not generate a magnetic field, the plunger 135 approaches the valve seat member 312 in response to the biasing force of the compression coil spring 137, and the ball 136 blocks the end opening of the through hole 312a. This blocks communication between the high pressure chamber HS and the pressure adjustment passage 222.

[0048] 3 along the axis O2 against the biasing force of the compression spring 316, and the tapered surface of the flange portion 313b moves away from the end face of the valve shaft member 313. Then, the refrigerant supplied from the pipe H5 via the pressure equalizing passage 23 passes through the communication hole 314e and the bypass passage 314d, the gap between the valve shaft member 313 and the through hole 312a, the circumferential groove 312b, the radial hole 312c, and the pressure adjustment passage 222, and is introduced into the lower space LC, so that the expansion valve 1 can perform its normal valve operation.

[0049] Specifically, when the valve element 3 is seated on the valve seat 20 (in a non-communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 103 is restricted. On the other hand, when the valve element 3 is separated from the valve seat 20 (in a communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 103 increases.

[0050] When the internal pressure of the upper space UC decreases relative to the internal pressure of the lower space LC, the diaphragm 83 rises, and the valve body 3 moves upward together with the stopper member 84 and the operating rod 5 in response to the biasing force of the coil spring 41. On the other hand, when the internal pressure of the upper space UC increases relative to the internal pressure of the lower space LC, the diaphragm 83 and the stopper member 84 are pressed downward, and the operating rod 5 moves downward to press down the valve body 3. In this manner, the expansion valve 1 is switched between the open state and the closed state.

[0051] Furthermore, when the flow rate of the refrigerant sent from the expansion valve 1 to the evaporator 103 changes, the temperature and pressure flowing in the outlet pipe H3 also change. The internal pressure of the lower space LC and the upper space UC changes accordingly, and the amount of drive of the working rod 5 by the power element also changes accordingly. In other words, in the expansion valve 1, the amount of refrigerant supplied from the expansion valve 1 to the evaporator 103 is automatically adjusted according to the temperature and pressure of the refrigerant returning to the expansion valve 1 from the evaporator 103.

[0052] Next, a forced valve closing operation of the expansion valve 1 using the solenoid valve EV will be described. In the solenoid valve EV, the displacement position of the ball 136 and the valve shaft member 313 when the ball 136 of the plunger 135 presses the exposed end of the valve shaft member 313 and abuts against the valve seat member 312 is defined as a second position, and the displacement position of the ball 136 and the valve shaft member 313 when the ball 136 of the plunger 135 separates from the valve shaft member 313 and the valve seat member 312 is defined as a first position. A high-pressure refrigerant is supplied to the high-pressure chamber HS between the base 120 and the valve body 2 from the valve chamber VS via an inlet hole 314h.

[0053] When the solenoid valve EV is turned on by a command from an external control device, a magnetic field is generated by a coil (not shown), and the plunger 135 is urged to move in a direction away from the valve seat member 312 against the urging force of the compression coil spring 137 as shown in Fig. 3. As a result, the ball 136 of the plunger 135 moves away from the open end of the through hole 312a, while the flange portion 313b of the valve shaft member 313 abuts against the other end of the through hole 312a due to the urging force of the compression spring 316, and the ball 136 and the valve shaft member 313 are in the first position.

[0054] In the first position, the pressure of the refrigerant in the high pressure chamber HS is transmitted from the circular through hole 312a of the valve seat member 312 through the radial hole 312c, the circumferential groove 312b, and the pressure adjustment passage 222 to the lower space LC, making the internal pressure of the lower space LC high. Meanwhile, since the flange portion 313b covers the other end of the circular through hole 312a, leakage of the refrigerant from the high pressure chamber HS through the circular through hole 312a and the bypass passage 314d to the pressure equalizing passage 23 side is suppressed, and the internal pressure of the lower space LC remains high.

[0055] When the lower space LC becomes high pressure, the lower space LC expands due to the pressure difference with the upper space UC, and the diaphragm 83 is displaced away from the valve body 2. In this state, even if the pressure in the upper space UC increases, the pressure in the lower space LC is higher, so that no driving force is transmitted from the diaphragm 83 to the actuating rod 5, and therefore the expansion valve 1 is forcibly maintained in a closed state.

[0056] In contrast, when the solenoid valve EV is turned off by a command from an external control device, the magnetic field of the coil (not shown) disappears, and the ball 136 of the plunger 135 approaches the valve seat member 312 in response to the biasing force of the compression coil spring 137 to the second position, and the ball 136 blocks the end opening of the through hole 312a. This blocks communication between the high pressure chamber HS and the pressure adjustment passage 222.

[0057] Furthermore, when the ball 136 pushes the end of the valve shaft member 313 into the through hole 312a, the valve shaft member 313 is displaced leftward in FIG. 3 along the axis O2 against the biasing force of the compression spring 316 to the second position, and the tapered surface of the flange portion 313b is separated from the end face of the valve shaft member 313. Then, the lower space LC and the pressure equalizing passage 23 communicate with each other via the pressure adjustment passage 222, the circumferential groove 312b, the radial hole 312c, the bypass passage 314d, and the communication hole 314e, so that the pressure in the lower space LC is promptly reduced and the original valve operation of the expansion valve 1 can be ensured. As described above, it is possible to provide an expansion valve 1 that can arbitrarily ensure a closed state while miniaturizing the solenoid valve EV.

[0058] (Modification) 7 and 8 are cross-sectional views similar to FIG. 3 of an expansion valve according to a modified example, with FIG. 7 showing the solenoid valve in an on state and FIG. 8 showing the solenoid valve in an off state.

[0059] In the expansion valve of this modified example, only the valve body 2A, the valve seat member 312A, and the plunger 135A are different from those of the first embodiment, and the other configurations are the same as those of the first embodiment. Therefore, the same symbols are used for the common configurations and redundant explanations are omitted.

[0060] In the valve body 2A, the small opening 314Ac is longer than in the first embodiment, and the lower end of the pressure adjustment passage 222A communicates with the bypass passage 314Ad on the pressure equalizing passage 23 side of the valve shaft member 312A. Other than that, the configuration of the valve body 2A is the same as in the above-mentioned embodiment, so the same reference numerals are used and the description will be omitted.

[0061] The valve seat member 312A does not have a circumferential groove or a radial hole, but otherwise has the same configuration as the above-described embodiment, so the same reference numerals are used and the description is omitted.

[0062] The plunger 135A has a shorter overall length than that of the solenoid valve of the first embodiment. Other than that, the configuration of the solenoid valve EV is similar to that of the above-mentioned embodiments, so the same reference numerals are used and repeated explanations are omitted.

[0063] When the solenoid valve EV is turned on by a command from an external control device, a magnetic field is generated from a coil (not shown), and as shown in Fig. 7, the plunger 135A moves away from the valve seat member 312 against the biasing force of the compression coil spring 137. As a result, the ball 136 of the plunger 135A moves away from the end of the valve shaft member 313 and becomes the second position.

[0064] 7 to the second position in response to the biasing force of the compression spring 316, and the tapered surface of the flange portion 313b covers the end of the opposing circular through hole 312a. This allows the pressure equalizing passage 23 to communicate with the lower space LC (see FIG. 1) via the pressure adjustment passage 222A, and blocks communication between the high pressure chamber HS and the lower space LC. As a result, the expansion valve can operate normally.

[0065] On the other hand, when the solenoid valve EV is turned off by a command from an external control device, the magnetic field of the coil (not shown) disappears, and as shown in FIG. 8, the plunger 135A approaches the valve seat member 312A in response to the biasing force of the compression coil spring 137, but the ball 136 is maintained in a state where it does not abut against the valve seat member 312A (the first position which is closer to the valve seat member 312A than the second position).

[0066] At this time, the ball 136 at the tip of the plunger 135A comes into contact with the tip of the valve shaft member 313 exposed from the through hole 312a, displacing the valve shaft member 313 to the first position on the left side in Fig. 8, and pressing the flange portion 313b against the step (inner peripheral step) between the small opening 314Ac and the bypass passage 314Ad to come into contact with it over the entire circumference. This blocks the bypass passage 314Ad, and therefore blocks communication between the lower space LC and the pressure equalizing passage 23.

[0067] Since the ball 136 does not contact the valve seat member 312, the open end of the through hole 312a remains open, and the high pressure chamber HS and the lower space LC (see FIG. 1) communicate with each other via the pressure adjustment passage 222A. This allows the expansion valve to be forcibly closed. This modification can also be applied to the second embodiment described below.

[0068] Second embodiment Figures 9 and 10 are longitudinal cross-sectional views of an expansion valve 1B according to a second embodiment, with the solenoid valve EV in an ON state in Figure 9 and the solenoid valve EV in an OFF state in Figure 10. Figure 11 is a cross-sectional view showing the EE cross section of Figure 9 as viewed in a plane, and Figure 12 is a cross-sectional view showing the FF cross section of Figure 9 as viewed in a plane. Note that piping is omitted in Figures 11 and 12.

[0069] In the expansion valve of this embodiment, the axis L and the axis O2 intersect, and the valve body 2B and the actuating rod 5B are different from those of the first embodiment. The other configurations are the same as those of the first embodiment, so the same symbols are used for the common configurations and duplicate explanations are omitted.

[0070] The valve body 2B has an orifice hole 27B that connects a first flow path 21B to which a pipe H1 (see FIG. 1) is connected and a valve chamber VS, and the valve element 3 is seated on a valve seat 20 at the lower end of the orifice hole 27B. An inlet hole 314h that connects to a high pressure chamber HS is connected to the first flow path 21B. The valve chamber VS communicates with a second flow path (not shown) that is connected to a pipe H2.

[0071] In the valve body 2B, as shown in Fig. 12, a plurality of (e.g., three) actuating rod insertion holes 28B are formed at equal intervals in the circumferential direction at positions equidistant from the axis L that coincides with the center line of the orifice hole 27B, and an actuating rod 5B is slidably fitted into each of the actuating rod insertion holes 28B. The upper end of the actuating rod 5B can abut against the lower end of the disk portion 84a of the stopper member 84, and the lower end of the actuating rod 5B abuts against the upper surface of the guide portion 3b of the valve body 3. The cylindrical portion 84b of the stopper member 84 slidably fits into the upper end of the pressure adjustment passage 222B whose center line is along the axis L. Other than that, the configurations of the valve body 2B and the actuating rod 5B are the same as those of the first embodiment, so repeated explanations will be omitted.

[0072] 10, when the solenoid valve EV is in the OFF state, the ball 136 and the valve shaft member 313 are displaced to the second position, as in the first embodiment. As a result, the pressure equalizing passage 23 connected to the pipe H5 communicates with the lower space LC of the power element 8 via the pressure adjustment passage 222B, and the high pressure chamber HS is blocked from the pressure adjustment passage 222B, allowing the expansion valve 1B to perform its normal valve operation.

[0073] For example, when the pressure in the upper space UC of the power element 8 is higher than the pressure in the lower space LC, the diaphragm 83 deforms downward, and the driving force is transmitted to the valve body 3 via the stopper member 84 and the three operating rods 5B, and the valve body 3 moves away from the valve seat 20. At this time, the refrigerant that has entered from the first flow path 21B passes between the valve seat 20 and the valve body 3 from the orifice hole 27B, reaches the valve chamber VS, and is further discharged from the expansion valve 1B via the second flow path.

[0074] On the other hand, when the pressure in the upper space UC of the power element 8 becomes lower than the pressure in the lower space LC, the three operating rods 5B are displaced upward by the biasing force of the biasing device 4, the valve body 3 is seated on the valve seat 20, and the refrigerant flowing from the orifice hole 27B to the valve chamber VS is restricted.

[0075] 9, when the solenoid valve EV is in the on state, the ball 136 and the valve shaft member 313 are displaced to the first position, as in the first embodiment. As a result, the high pressure chamber HS and the lower space LC of the power element 8 are communicated via the pressure adjustment passage 222B, and the pressure equalizing passage 23 and the pressure adjustment passage 222B are blocked, so that the pressure in the lower space LC becomes substantially equal to the pressure in the first flow path 21B, and the forced closing operation of the expansion valve 1B can be realized.

[0076] In the first and second embodiments, the solenoid valve EV is a so-called normally closed type in which the attractor 140 is disposed on the opposite side of the plunger 150 from the seating member 312 and the ball 136 is seated on the seating member 312 in the non-powered state. However, a solenoid valve of a normally open type in which the ball 136 is seated on the seating member 312 in the powered state may be adopted as the solenoid valve EV of the first and second embodiments. A normally open type solenoid valve is already known, for example, one in which the attractor 140 is provided on the seating member 312 side with respect to the plunger 150, but a detailed description thereof will be omitted here. In the case of a normally open type solenoid valve, the first and second positions of the ball 136 are reversed in the on and off states of the solenoid valve EV in the first and second embodiments.

[0077] This specification includes the disclosure of the following inventions. (First aspect) a valve body including a valve chamber, a valve seat, a high pressure chamber to which a refrigerant having a first pressure is supplied, and a pressure equalizing passage to which a refrigerant having a second pressure lower than the first pressure is supplied; a valve body disposed in the valve chamber; a power element provided in the valve body and including a diaphragm for separating a first space in which a working fluid is sealed and a second space capable of communicating with the pressure equalizing path; a biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and configured to transmit the displacement of the diaphragm to the valve element; a movable valve drive device for displacing a movable valve within the valve body, when the movable valve drive device displaces the movable valve to a first position, the second space communicates with the high pressure chamber and communication between the second space and the pressure equalizing path is blocked, and when the movable valve drive device displaces the movable valve to a second position, the second space communicates with the pressure equalizing path and communication between the second space and the high pressure chamber is blocked. An expansion valve characterized by:

[0078] (Second aspect) the valve body has a switching hole capable of communicating with the pressure equalizing passage and the high pressure chamber, and a pressure regulating passage capable of communicating with the second space and the switching hole, When the movable valve is in the first position, the pressure adjustment passage communicates with the high pressure chamber while blocking communication between the pressure adjustment passage and the pressure equalizing passage, and when the movable valve is in the second position, the pressure adjustment passage communicates with the pressure equalizing passage while blocking communication between the pressure adjustment passage and the high pressure chamber. An expansion valve according to a first aspect, characterized in that:

[0079] (Third aspect) The axis of the valve body and the axis of the actuation rod coincide with each other. An expansion valve according to a second aspect,

[0080] (Fourth aspect) A plurality of the actuating rods are arranged around the axis of the valve body. An expansion valve according to a second aspect,

[0081] (Fifth aspect) The movable valve drive device has a plunger and an electromagnetic valve equipped with an attractor capable of attracting the plunger by magnetic force when power is supplied, and displaces the movable valve by the plunger. The expansion valve according to any one of the first to fourth aspects, characterized in that:

[0082] (Sixth aspect) the valve body has a side opening communicating with the pressure equalizing passage and the high pressure chamber, a seating member having a through hole communicating with the pressure adjustment passage through a side wall is disposed within the side opening, a shaft member is slidably disposed within the through hole, the shaft member has a flange portion outside the through hole, and a compression spring urges the flange portion toward an end of the through hole on the pressure equalizing passage side, when the movable valve is displaced to the first position, the movable valve is separated from the high pressure chamber side end of the shaft member, and the flange portion closes the pressure equalizing passage side end of the through hole, when the movable valve is displaced to the second position, the movable valve presses against one end of the shaft member to close the high pressure chamber side end of the circular through hole, and the flange portion moves away from the pressure equalizing passage side end of the circular through hole. The expansion valve according to any one of the second to fourth aspects, characterized in that:

[0083] (Seventh aspect) the valve body includes a side opening communicating with the pressure equalizing passage, the high pressure chamber, and the pressure adjustment passage, and having an inner circumferential step portion, a seating member having a through hole is disposed in the side opening on the high pressure chamber side of the pressure adjustment passage, and a shaft member is slidably disposed in the through hole, the shaft member has a flange portion outside the through hole facing the inner circumferential step portion, and a compression spring urges the flange portion toward an end of the through hole on the pressure equalizing passage side, when the movable valve is displaced to the first position, the movable valve presses the high-pressure chamber side end of the shaft member in a state in which the movable valve does not cover the high-pressure chamber side end of the through hole, whereby the flange portion abuts on the entire circumference of the inner peripheral step portion of the side opening, when the movable valve is displaced to the second position, the movable valve is separated from a high pressure chamber side end of the through hole, and the flange portion closes a pressure equalizing passage side end of the through hole. The expansion valve according to any one of the second to fourth aspects, characterized in that: [Explanation of symbols]

[0084] 1, 1B: Expansion valve 2, 2A, 2B: Valve body 3: Valve body 4: Actuating device 5, 5B: Operating rod 8: Power Element 20: Valve seat 23: Pressure equalizing circuit 140: Attractor 135: Plunger 136: Ball 222, 222A, 222B: Pressure regulation path 312, 312A: Valve seat member 313: Valve stem components EV: Solenoid valve VS: Valve chamber HS: Hyperbaric chamber

Claims

1. a valve body including a valve chamber, a valve seat, a high pressure chamber to which a refrigerant having a first pressure is supplied, and a pressure equalizing passage to which a refrigerant having a second pressure lower than the first pressure is supplied; a valve body disposed in the valve chamber; a power element provided in the valve body and including a diaphragm for separating a first space in which a working fluid is sealed and a second space capable of communicating with the pressure equalizing path; a biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and configured to transmit the displacement of the diaphragm to the valve element; a movable valve drive device for displacing a movable valve within the valve body, when the movable valve drive device displaces the movable valve to a first position, the second space communicates with the high pressure chamber and communication between the second space and the pressure equalizing path is blocked, and when the movable valve drive device displaces the movable valve to a second position, the second space communicates with the pressure equalizing path and communication between the second space and the high pressure chamber is blocked. An expansion valve characterized by:

2. the valve body has a switching hole capable of communicating with the pressure equalizing passage and the high pressure chamber, and a pressure regulating passage capable of communicating with the second space and the switching hole, When the movable valve is in the first position, the pressure adjustment passage communicates with the high pressure chamber while blocking communication between the pressure adjustment passage and the pressure equalizing passage, and when the movable valve is in the second position, the pressure adjustment passage communicates with the pressure equalizing passage while blocking communication between the pressure adjustment passage and the high pressure chamber.

2. The expansion valve according to claim 1 .

3. The axis of the valve body and the axis of the actuation rod coincide with each other.

3. The expansion valve according to claim 2.

4. A plurality of the actuating rods are arranged around the axis of the valve body.

3. The expansion valve according to claim 2.

5. The movable valve drive device has a plunger and an electromagnetic valve equipped with an attractor capable of attracting the plunger by magnetic force when power is supplied, and displaces the movable valve by the plunger.

2. The expansion valve according to claim 1 .

6. the valve body has a side opening communicating with the pressure equalizing passage and the high pressure chamber, a seating member having a through hole communicating with the pressure adjustment passage through a side wall is disposed within the side opening, a shaft member is slidably disposed within the through hole, the shaft member has a flange portion outside the through hole, and a compression spring urges the flange portion toward an end of the through hole on the pressure equalizing passage side, when the movable valve is displaced to the first position, the movable valve is separated from the high pressure chamber side end of the shaft member, and the flange portion closes the pressure equalizing passage side end of the through hole, when the movable valve is displaced to the second position, the movable valve presses against one end of the shaft member to close the high pressure chamber side end of the through hole, and the flange portion moves away from the pressure equalizing passage side end of the through hole.

3. The expansion valve according to claim 2.

7. the valve body includes a side opening communicating with the pressure equalizing passage, the high pressure chamber, and the pressure adjustment passage, and having an inner circumferential step portion, a seating member having a through hole is disposed in the side opening on the high pressure chamber side of the pressure adjustment passage, and a shaft member is slidably disposed in the through hole, the shaft member has a flange portion outside the through hole facing the inner circumferential step portion, and a compression spring urges the flange portion toward an end of the through hole on the pressure equalizing passage side, when the movable valve is displaced to the first position, the movable valve presses the high pressure chamber side end of the shaft member while not covering the high pressure chamber side end of the through hole, whereby the flange portion abuts on the entire circumference of the inner peripheral step portion of the side opening, when the movable valve is displaced to the second position, the movable valve is separated from a high pressure chamber side end of the through hole, and the flange portion closes a pressure equalizing passage side end of the through hole.

3. The expansion valve according to claim 2.

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