Expansion valve

Abstract

To provide an expansion valve that can ensure a valve closed state as needed, and can nevertheless suppress a pressure loss.SOLUTION: An expansion valve comprises: a valve body having a valve chamber and a valve seat; a valve element disposed in the valve chamber; a power element that is provided in the valve body and generates force for separating the valve element from the valve seat to open the valve; a first biasing device that biases the valve element toward the valve seat; an operation rod that is provided in the valve body and drives the valve element; a piston member that is provided between the power element and the operation rod and configures, together with the power element, a cylinder chamber which is extendable in the direction of movement of the valve element, the piston member transmitting the force generated from the power element to the operation rod; and a supply section that supplies a refrigerant in the valve chamber or a refrigerant upstream of the valve chamber to the cylinder chamber.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] One type of expansion valve is a solenoid-operated expansion valve, which is used in a refrigeration cycle having multiple evaporators connected in parallel, and has the function of controlling the degree of superheat of the refrigerant at the outlet of the evaporators as well as the function of shutting off the circuit in the refrigeration cycle.

[0003] Patent Document 1 discloses an expansion valve having a valve port provided in a communication passage connecting a primary passage into which high-pressure refrigerant flows and a valve chamber, and equipped with a solenoid valve that opens or closes the valve port. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3362990 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-266543 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the configuration of Patent Document 1, the expansion valve is operated by opening the valve port using the solenoid valve, and the expansion valve can be forcibly closed by closing the valve port.

[0006] According to the expansion valve of Patent Document 1, the solenoid valve and the expansion valve are connected in series. That is, the refrigerant that enters the primary passage must pass through two orifices, the solenoid valve orifice and the expansion valve orifice, before flowing out of the expansion valve, which increases pressure loss.

[0007] One idea is to forcefully close the expansion valve by using a high-pressure refrigerant to bias the actuating rod toward the power element, for example. However, in such a configuration, it becomes necessary to make the housing of the power element strong in order to prevent the diaphragm from being deformed by excessive force from the actuating rod, as shown in Patent Document 2, for example, which may result in an increase in the weight and size of the expansion valve.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to provide an expansion valve that can suppress pressure loss while maintaining a closed valve state at will. [Means for solving the problem]

[0009] The solenoid valve of the present invention comprises: a valve body having a valve chamber and a valve seat; a valve body disposed in the valve chamber; a power element provided in the valve body and generating a force to separate the valve element from the valve seat and open the valve; a first biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and driving the valve element; a piston member that, together with the power element, defines a cylinder chamber that is extendable and contractible in the direction of movement of the valve body and that transmits force generated by the power element to the actuation rod; The cylinder chamber is characterized by including a supply section that supplies the refrigerant in the valve chamber or the refrigerant upstream of the valve chamber. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an expansion valve that can suppress pressure loss while maintaining a closed valve state at will. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an expansion valve in a closed state according to a first embodiment. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of the expansion valve in a cross section shifted in phase by 90 degrees around the axis L from FIG. [Figure 3] 3 is an enlarged cross-sectional view showing the periphery of the solenoid valve shown in FIG. 2. [Figure 4] FIG. 4 is a vertical cross-sectional view similar to that of FIG. 2, showing the expansion valve in a closed state. [Figure 5] FIG. 5 is a vertical cross-sectional view showing an open state of the expansion valve according to the second embodiment. [Figure 6] FIG. 6 is a vertical cross-sectional view showing the expansion valve in the closed state according to the second embodiment. [Figure 7] FIG. 7 is a vertical cross-sectional view similar to FIG. 5 of an expansion valve according to a modified example. [Figure 8] FIG. 8 is a vertical cross-sectional view similar to FIG. 5 of an expansion valve according to another modified example. [Figure 9] FIG. 9 is an enlarged cross-sectional view showing a state immediately before the piston member of the modified example is assembled into the enlarged diameter hole. [Figure 10] FIG. 10 is a diagram schematically illustrating an example in which the external pressure equalizing expansion valve according to the third embodiment is applied to a refrigerant circulation system. [Figure 11] FIG. 11 is a vertical cross-sectional view showing an external pressure equalizing expansion valve according to a third embodiment in an open state. [Figure 12] FIG. 12 is a vertical cross-sectional view showing the external pressure equalizing expansion valve according to the third embodiment in a closed state. [Figure 13] FIG. 13 is an enlarged cross-sectional view showing the periphery of a side opening of a modified example. [Figure 14] FIG. 14 is a vertical cross-sectional view showing an open state of an external pressure equalizing expansion valve according to a modified example. [Figure 15] FIG. 15 is a vertical cross-sectional view showing an open state of an external pressure equalizing expansion valve according to a modified example. [Figure 16] FIG. 16 is a vertical cross-sectional view showing an expansion valve according to a modified example of the second embodiment. [Figure 17] FIG. 17 is a vertical cross-sectional view showing an expansion valve in another modified example of the second embodiment. [Figure 18] FIG. 18 is a vertical cross-sectional view showing an expansion valve in another modified example of the second embodiment. [Figure 19] FIG. 19 is a vertical cross-sectional view showing an expansion valve in another modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] (First embodiment) The structure of the expansion valve 1 according to the first embodiment will be described below with reference to FIG. Fig. 1 is a schematic cross-sectional view of an expansion valve 1 in this embodiment in a closed state, and schematically shows a refrigeration cycle 100 to which this is connected. Fig. 2 is a longitudinal cross-sectional view of the expansion valve 1 in a cross section shifted by 90 degrees around the axis L from Fig. 1, showing the open state. Fig. 3 is an enlarged cross-sectional view of the periphery of the solenoid valve EV shown in Fig. 2. Fig. 4 is a longitudinal cross-sectional view of the expansion valve 1 in the same cross section as Fig. 2, showing the closed state.

[0013] The expansion valve 1 comprises a valve body 2 having a valve chamber VS, a valve element 3, a biasing device (also referred to as a first biasing device) 4, an operating rod 5, a piston member 6, and a power element 8. The axis of the expansion valve 1 is designated as L. Here, along the axis L, the power element 8 side is designated as the upper side, and the biasing device 4 side is designated as the lower side.

[0014] In addition to the valve chamber VS, the valve body 2 is equipped with a first flow path 21, a second flow path 22, and a return flow path (low-pressure flow path or pressure equalization path) 23. The first flow path 21 is a supply-side flow path, and a refrigerant (also referred to as fluid) 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 actuating rod insertion hole 27, the intermediate passage 22a, and the discharge-side flow path. The first flow path 21 and the valve chamber VS are connected via a small-diameter passage 21a.

[0015] The spherical valve element 3 is disposed in the valve chamber VS. When the valve element 3 is seated on the annular valve seat 20 of the valve body 2, the valve chamber VS and the second flow path 22 are not in communication with each other. On the other hand, when the valve element 3 is separated from the valve seat 20, the valve chamber VS and the second flow path 22 are in communication with each other.

[0016] The actuating rod 5 is inserted through an actuating rod insertion hole 27 of the valve body 2 with a gap therebetween, and is guided by a central hole 28 and held so as to be displaceable in the direction of the axis L. The lower end of the actuating rod 5 contacts the upper surface of the valve body 3, and the upper end of the actuating rod 5 abuts against the lower end of the piston member 6.

[0017] The actuating rod 5 can press the valve element 3 in the valve opening direction against the biasing force of the biasing device 4. When the actuating rod 5 moves toward the valve element, the valve element 3 moves away from the valve seat 20, and the expansion valve 1 enters the open state.

[0018] The piston member 6 is composed of a disk base (also simply referred to as a base) 61 at the upper end side and a shaft (also referred to as a piston member shaft) 62 at the lower end side, which are coaxially connected, and has a blind hole 63 extending from the upper end side to near the lower end. The disk base 61 is housed in a cylindrical recess 84a of a stopper member 84 (described later) of the power element 8. A first circumferential groove 61a is formed on the outer periphery of the disk base 61, and a first O-ring OR1 is disposed inside the first circumferential groove 61a to seal between the cylindrical recess 84a and the disk base 61.

[0019] A second circumferential groove 62a and a third circumferential groove 62b are formed on the outer periphery near the lower end of the shaft portion 62, and a second O-ring OR2 and a third O-ring OR3 are respectively arranged inside these grooves to seal between the expanded diameter hole (first hole) 26 of the valve body 2 and the shaft portion 62.

[0020] The outer diameter of the shaft portion 62 is equal on both sides of the second circumferential groove 62a in the direction of the axis L, and the outer diameter of the shaft portion 62 is equal on both sides of the third circumferential groove 62b in the direction of the axis L, but a smaller-diameter reduced-diameter portion 62c is formed between the second circumferential groove 62a and the third circumferential groove 62b. The blind hole 63 and the reduced-diameter portion 62c are in communication via a connecting hole 62d. The inlet hole 2h, the high-pressure chamber HS, the middle opening 2f, the communicating hole 2d, the enlarged-diameter hole 26, the connecting hole 62d, and the blind hole 63 form an inlet passage, the connecting hole 62d and the blind hole 63 form a second hole, the inlet hole 2h form a first flow path portion, and the communicating hole 2d form a second flow path portion.

[0021] Here, the space between the expanded diameter hole 26, sealed by the second O-ring OR2 and the third O-ring OR3, and the reduced diameter portion 62c is referred to as a pressure equalizing chamber (also referred to as a pressure equalizing space) EC. The expanded diameter hole 26 has a uniform inner diameter, and a communication hole 2d is formed in the valve body 2, extending downward from the expanded diameter hole 26 facing the pressure equalizing chamber EC at an angle with respect to the axis L (see FIG. 2).

[0022] The piston member 6 extends along the axis L from the operating rod 5 to the power element 8 through an enlarged diameter hole 26 formed in the valve body 2, the return flow passage 23, and the communication passage 2b.

[0023] Next, we will explain the power element 8. The power element 8 is attached to an opening 2a provided at the top of the valve body 2. The opening 2a communicates with a return flow path 23 through which the refrigerant from the evaporator passes via a communication path 2b.

[0024] The power element 8 has a plug 81 , an upper cover member 82 , a diaphragm 83 , a stopper member 84 , and a receiving member 86 .

[0025] A hole 82 a is formed at the top of the upper cover member 82 and can be sealed with a plug 81 .

[0026] The diaphragm 83 is made of a thin plate material on which a plurality of concentric circular concave and convex shapes are formed.

[0027] The stopper member 84 has a disk portion 84b and a circular pipe portion 84c coaxially connected to the lower surface of the disk portion 84b, with the inside of the circular pipe portion 84c forming a cylindrical recess 84a. An annular locking member 85 is attached to the inner circumferential step at the lower end of the circular pipe portion 84c. After the disk base 61 of the piston member 6 is inserted into the cylindrical recess 84a, a crimping portion 84d disposed on the outer periphery of the locking member 85 is crimped radially inward to attach the locking member 85 to the circular pipe portion 84c, thereby preventing the disk base 61 from coming off the stopper member 84.

[0028] That is, the stopper member 84 and the piston member 6 are provided with locking portions (also referred to as stopper portions) that abut against each other to prevent the piston member 6 from moving beyond a predetermined position relative to the stopper member 84 toward the valve chamber. In other words, the locking member 85 of the stopper member 84 constitutes a part of the locking portion, and the part of the piston member 6 that abuts against the locking member 85 constitutes a part of the locking portion. Note that, although an example has been described in which the part of the stopper member 84 that abuts against the piston member 6 is formed as a separate member as the locking member 85, the part of the stopper member 84 that abuts against the piston member 6 may be formed integrally with the stopper member 84.

[0029] The disk base 61 is movable in the axial direction between an upper position (FIG. 4) where its upper end abuts against the lower surface of the disk portion 84b, and a lower position (FIG. 2) where its lower end abuts against the upper surface of the locking member 85. With the disk base 61 held in the lower position, the distance along the axis L from the upper end of the stopper member 84 to the lower end of the operating rod 5 is a specified value at which the expansion valve 1 is operable. Note that the embodiment is not limited to one in which the disk base 61 abuts against the disk portion 84b, and an axial clearance may be provided between them.

[0030] Here, the space between the disk portion 84b and the disk base 61 is referred to as a cylinder chamber CS. The cylinder chamber CS is connected only to the blind hole 63. An annular recess 84e, which is annularly recessed, is formed on the underside of the disk portion 84b facing the outer periphery of the upper end of the disk base 61, and the inside of the annular recess 84e forms part of the cylinder chamber CS.

[0031] The receiving member 86 has a flange portion having an outer diameter approximately the same as that of the upper cover member 82, and a hollow cylindrical portion connected to the lower end of the flange portion, and a male thread 86c is formed on the outer periphery of the hollow cylindrical portion.

[0032] When assembling the power element 8, the stopper member 84 to which the piston member 6 is attached is placed inside, and the outer peripheries of the upper cover member 82, the diaphragm 83, and the flange portion of the receiving member 86 are overlapped, and the outer peripheries are circumferentially welded together by, for example, TIG welding, laser welding, plasma welding, etc.

[0033] Next, working gas is injected into the space surrounded by the upper cover member 82 and the diaphragm 83 (referred to as the pressure actuated chamber PA) through the hole 82a formed in the upper cover member 82, and then the hole 82a is sealed with a plug 81, and the plug 81 is fixed to the upper cover member 82 using projection welding or the like.

[0034] At this time, the diaphragm 83 is pressurized by the working gas sealed in the pressure actuated chamber PA in a manner that causes it to bulge toward the receiving member 86, and is supported by abutting against the upper surface of the stopper member 84 disposed in the lower space LS surrounded by the diaphragm 83 and the receiving member 86. Note that, since the disk portion 84b of the stopper member 84 is held by the receiving member 86, the stopper member 84 will not come out of the power element 8.

[0035] When assembling the power element 8 to the valve body 2, after inserting the actuating rod 5 into the valve body 2, the piston member 6 together with the stopper member 84 are inserted into the valve body 2 from their lower ends. Furthermore, the male threads 86c of the receiving member 86 are threaded into the female threads of the opening 2a of the valve body 2, and the power element 8 is fixed to the valve body 2 by screwing it in. The gap between the valve body 2 and the power element 8 is sealed by a packing PK. In this state, the lower space LS of the power element 8 communicates with the return flow path 23, i.e., they have the same internal pressure.

[0036] Next, the biasing device 4 will be described. In Fig. 1, the biasing device 4 has a coil spring 41 made of a circular wire wound in a spiral shape, a valve element support 42 attached to the upper end of the coil spring 41 to support the valve element 3, a spring receiving member 43 attached to the valve body 2 while supporting the lower end of the coil spring 41, and a vibration-damping member 44 sandwiched between the valve element support 42 and the coil spring 41. The spring receiving member 43 seals the valve chamber VS of the valve body 2 and has the function of supporting the end of the coil spring 41, which biases the valve element 3 toward the valve seat 20.

[0037] The spherical valve element 3 is welded to the upper surface of the valve element support 42, and the two are integrally formed. The vibration-damping member 44 has, for example, radially protruding claws that elastically engage with the inner periphery of the valve chamber VS, and functions to suppress vibration of the valve element 3. Note that the vibration-damping member 44 is described in detail in, for example, JP 2018-025331 A, and therefore a detailed description thereof will be omitted.

[0038] (Solenoid valve structure) Next, the structure of the solenoid valve EV of this embodiment will be described with reference to Figures 2 and 3. The solenoid valve EV is a first valve device and a second valve device, or a drive unit, that can switch between a state in which the inflow path is open and the outflow path is closed, and a state in which the outflow path is open and the inflow path is closed. The inflow path and the solenoid valve EV constitute a supply unit and a discharge unit. The axis of the solenoid valve EV is designated as O. The axis O is perpendicular to the axis L.

[0039] 2, the valve body 2 is formed with a circular large opening 2e that opens outward along the axis O, a medium opening 2f with a smaller diameter than the large opening 2e, and a small opening 2g with a smaller diameter than the medium opening 2f. The bottom of the large opening 2e communicates with the valve chamber VS via an inlet hole 2h. A communication hole 2d opens on the inner periphery at a midpoint of the medium opening 2f. The bottom of the small opening 2g communicates with the intermediate passage 22a via an outlet hole (also called a connecting passage) 2j.

[0040] Here, the blind hole 63, the connecting hole 62d, the enlarged diameter hole 26, the communicating hole 2d, the medium opening 2f, the small opening 2g, and the outlet hole 2j form an outflow path. The small opening 2g and the outlet hole 2j form a branch flow path, the outlet hole 2j forms a third flow path portion, and the high-pressure chamber HS, the medium opening 2f, and the small opening 2g form a connecting chamber. The intermediate passage 22a forms a downstream flow path downstream of the valve seat 20.

[0041] 3, a cylindrical valve seat member 112 is disposed within the middle opening 2f, and is fixed to the middle opening 2f by crimping a cylindrical crimped portion 2i formed at the bottom of the large opening (also referred to as a recess) 2e radially inward. As will be described later, the valve seat member 112 is disposed between the opening of the first flow path portion and the opening of the third flow path portion within the connecting chamber to prevent the refrigerant from flowing from the first flow path portion to the third flow path portion, cover the opening of the second flow path portion, and form a gap between the opening of the third flow path portion and the valve seat member 112.

[0042] The valve seat member 112 has a circular through-hole (also referred to as a through hole) 112a extending along the axis O, a circumferential groove 112b formed around the entire outer periphery at a midpoint in the direction of the axis O, a radial hole 112c radially connecting the circular through-hole 112a and the circumferential groove 112b, and a recess 112d formed at the end on the small opening 2g side. The circumferential groove 112b is in communication with the communication hole 2d. The circumferential groove 112b and the radial hole 112c form a relay passage. Here, a part of the high-pressure chamber HS, the circular through-hole 112a, the radial hole 112c, and the circumferential groove 112b of the valve seat member 112 form a first communication passage, and the circular through-hole 112a, the radial hole 112c, the circumferential groove 112b, and the small opening 2g of the valve seat member 112 form a second communication passage.

[0043] An annular first seal member SL1 is attached by adhesive or the like within the recess 112d of the valve seat member 112, and an annular second seal member SL2 is attached by adhesive or the like to the end opposite the recess 112d. The inner diameters of the first seal member SL1 and the second seal member SL2 are approximately equal to the inner diameter of the through-hole 112a. The first seal member SL1 abuts against the step at the boundary between the middle opening 2f and the small opening 2g, and the second seal member SL2 abuts against the inner periphery of the middle opening 2f, thereby sealing the gap between the valve seat member 112 and the valve body 2.

[0044] The cylindrical valve stem member 113 has a long shaft portion (also simply referred to as a shaft portion) 113a inserted so as to penetrate the circular through-hole 112a of the valve seat member 112 and the first and second seal members SL1 and SL2, a flange portion 113b having a diameter larger than that of the circular through-hole 112a, and a short shaft portion 113c. Gaps through which the refrigerant can pass are provided between the outer periphery of the long shaft portion 113a and the inner peripheries of the circular through-hole 112a, the first and second seal members SL1 and SL2, and the valve stem member 113 is movable relative to the valve seat member 112 in the direction of the axis O. Specifically, the valve shaft member 113 is movable between a first position in which the third flow path portion is not connected to both the first flow path portion and the second flow path portion, and a second position in which the second flow path portion is connected to the third flow path portion via the second communicating flow path of the connection chamber, and the first flow path portion is not connected to both the second flow path portion and the third flow path portion.

[0045] A compression spring (also referred to as a second biasing device) 114 is disposed around the short shaft portion 113c between the bottom of the small opening 2g and the opposing surface of the flange portion 113b, and biases the valve shaft member 113 toward the large opening 2e with respect to the bottom of the small opening 2g. The solenoid valve EV and the compression spring 114 constitute a drive device.

[0046] The solenoid valve EV comprises an annular base 120, a coil 132 for energizing and energizing, a yoke 133, a pipe 141 arranged on the inner periphery of the yoke 133 and extending in the direction of the axis O, a plunger (displacement member) 135 arranged on the inner periphery of the pipe 141 so as to be able to slide freely in the direction of the axis O, an attractor 140 fixedly arranged on the inner periphery of the end of the pipe 141, and a housing 138 arranged to cover these.

[0047] An end of a pipe 141 is fixed to the inner periphery of the base 120 by press-fitting or brazing, and the base 120 is fixed to the valve body 2 by threading a male thread 121 formed on the outer periphery of the base 120 into a female thread 2k formed on the inner periphery of the large opening 2e of the valve body 2. An O-ring OR3 is disposed between the base 120 and the bottom of the large opening 2e to seal between the base 120 and the valve body 2. This forms a high-pressure chamber HS between the base 120 and the large opening 2e. The high-pressure chamber HS communicates with the inlet hole 2h and is also capable of communicating with the through-hole 112a of the valve seat member 112.

[0048] An internal thread portion 142 is formed on the end face of the suction element 140 opposite to the pipe 141. With the housing 138 interposed between them, a mounting bolt 137 is threadedly engaged with the internal thread portion 142, thereby joining the suction element 140 and the housing 138. The housing 138 is fixed to the base 120 via a spacer 139.

[0049] The cylindrical plunger 135 is made of a magnetic material and comprises an expanded-diameter cylindrical portion 135a and a reduced-diameter cylindrical portion 135b, the diameter of which is larger than the inner diameter of the circular through-hole 112a, connected together. A circular recess 135c is formed at the end of the reduced-diameter cylindrical portion 135b, into which the end of the long shaft portion 113a of the valve stem member 113, exposed from the valve seat member 112, is fitted loosely (i.e., relatively displaceable in the direction of the axis O). The plunger 135 is biased toward the valve seat member 112 by a compression coil spring 136, which is compressed between the plunger 135 and the attractor 140. The tip surface of the plunger 135 is formed into a surface that, when abutted against the valve stem member 113, causes the opening of the circular through-hole 112a and the connecting chamber to become disconnected.

[0050] (Expansion valve operation) An example of operation when the expansion valve 1 is incorporated into a refrigeration cycle 100 will be described with reference to Fig. 1. Refrigerant pressurized by a compressor 101 in the refrigeration cycle 100 is liquefied by a condenser 102 and sent to the expansion valve 1. The refrigerant adiabatically expanded by the expansion valve 1 is sent to an evaporator 103 of the refrigeration cycle 100, where it exchanges heat with air flowing around the evaporator 103. The refrigerant returning from the evaporator 103 passes through the expansion valve 1 (more specifically, the return flow path 23) and is returned to the compressor 101 side.

[0051] Assume that the plunger 135 of the solenoid valve EV is in a first position (described later) as shown in FIG. 2. In this state, the pressure of the refrigerant in the high-pressure chamber HS is transmitted from the through-hole 112a of the valve seat member 112 through the radial hole 112c, the circumferential groove 112b, and the communication hole 2d to the pressure-equalizing chamber EC. The pressure of the refrigerant in the pressure-equalizing chamber EC is further transmitted to the cylinder chamber CS through the connecting hole 62d and the blind hole 63, increasing the internal pressure of the cylinder chamber CS. As a result, the piston member 6 is pressed downward against the stopper member 84, maintaining the stopper member 84 and the actuating rod 5 spaced a predetermined distance apart in the axial direction. This allows the expansion valve 1 to perform its intended operation.

[0052] The expansion valve 1 is supplied with high-pressure refrigerant from a condenser 102. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to a first flow path 21.

[0053] When the valve disc 3 is seated on the valve seat 20, the first flow path 21 upstream of the valve chamber VS and the second flow path 22 downstream of the valve chamber VS are not in communication with each other. On the other hand, when the valve disc 3 is separated from the valve seat 20, the refrigerant supplied to the valve chamber VS is sent to the evaporator through the actuating rod insertion hole 27 and the second flow path 22. The expansion valve 1 is switched between a closed state (see FIG. 4) and an open state (FIG. 2) by an actuating rod 5 connected to a power element 8.

[0054] The power element 8 is provided with a pressure actuated chamber PA and a lower space LS separated by a diaphragm 83. Therefore, when the working gas in the pressure actuated chamber PA is liquefied, the biasing force of the biasing device 4 moves the working rod 5 toward the diaphragm, and when the liquefied working gas is vaporized, the driving force of the power element 8 is transmitted via the stopper member 84 and the piston member 6, and the working rod 5 moves toward the valve body. In this way, the expansion valve 1 is switched between the open state and the closed state.

[0055] Furthermore, the lower space LS of the power element 8 is connected to the return flow path 23. Therefore, the phase (gas phase, liquid phase, etc.) of the working gas in the pressure actuated chamber PA changes depending on the temperature and pressure of the refrigerant flowing through the return flow path 23, and the actuating rod 5 is driven via the piston member 6. In other words, in the expansion valve 1 shown in FIG. 1, the amount of refrigerant supplied from the expansion valve 1 to the evaporator is automatically adjusted depending on the temperature and pressure of the refrigerant returning to the expansion valve 1 from the evaporator.

[0056] (Expansion valve forced closing operation) Next, we will explain the forced valve closing operation of the expansion valve 1 using the solenoid valve EV. In the solenoid valve EV, the position where the plunger 135 abuts against the valve seat member 112 is defined as the second position, and the position where the plunger 135 is separated from the valve seat member 112 is defined as the first position. 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 the inlet hole 2h.

[0057] 2, when power is supplied to the coil 132 from an external power supply device, the plunger 135 is urged to move in a direction away from the valve seat member 112 against the urging force of the compression coil spring 136. As a result, the end of the plunger 135 moves away from the second seal member SL2, and the urging force of the compression spring 114 causes the flange portion 113b of the valve shaft member 113 to abut against the first seal member SL1, and the plunger 135 of the solenoid valve EV is in the first position.

[0058] In this first position, the pressure of the refrigerant in the high-pressure chamber HS is transmitted from the circular through-hole 112a of the valve seat member 112 through the radial hole 112c, the circumferential groove 112b, and the communication hole 2d to the equalizing chamber EC. When the pressure in the equalizing chamber EC becomes high, a relatively large axial force acts on the second O-ring OR2 and the third O-ring OR3 in opposing directions. However, because the inner diameters of the expanded diameter holes 26 where the second O-ring OR2 and the third O-ring OR3 contact are the same, the pressure-receiving areas of the O-rings on either side of the equalizing chamber EC are equal. Furthermore, the pressure on the upper side of the second O-ring OR2 and the pressure on the lower side of the third O-ring OR3 (i.e., the pressure difference with the equalizing chamber EC) are approximately equal. Therefore, the axial forces acting in both directions on the piston member 6 are canceled out, preventing the piston member 6 from moving even when the pressure in the equalizing chamber EC becomes high.

[0059] The pressure of the refrigerant in the pressure-equalizing chamber EC is further transmitted to the cylinder chamber CS via the connecting hole 62d and the blind hole 63, raising the internal pressure of the cylinder chamber CS. Meanwhile, because the flange portion 113b of the valve shaft member 113 abuts against the first seal member SL1, leakage of refrigerant from the high-pressure chamber HS through the circular through-hole 112a to the small opening 2g side is suppressed, and the internal pressures of the pressure-equalizing chamber EC and the cylinder chamber CS remain high.

[0060] The side of the piston member 6 opposite the cylinder chamber CS across the disk base 61 faces the return flow path (low-pressure space) 23 through which low-pressure refrigerant passes. When the cylinder chamber CS becomes high-pressure, the piston member 6 is subjected to a force in the direction of expanding the cylinder chamber CS due to the pressure difference with the pressure of the refrigerant in the return flow path 23, so that the piston member 6 is displaced away from the power element 8 and assumes a lower position where it is locked and held by the locking member 85. When the piston member 6 is locked in the lower position, the axial length from the upper end of the stopper member 84 to the lower end of the operating rod 5 becomes a specified value, so that the operating rod 5 can move up and down in accordance with the operation of the power element 8.

[0061] At this time, the pressure inside the cylinder chamber CS increases, and an upward force is applied that presses the diaphragm 83 via the stopper member 84, but at the same time, a downward force is also applied that presses the disk base 61 downward. This downward force is supported by the locking member 85, which cancels out the upward force that urges the stopper member 84 upward, thereby preventing the diaphragm 83 from being deformed or otherwise affected.

[0062] On the other hand, when power is not supplied to the coil 132 from the external power supply device, the plunger 135 is urged to move in a direction approaching the valve seat member 112 by the urging force of the compression coil spring 136, as shown in Fig. 4. As a result, the end of the plunger 135 abuts against the second seal member SL2, and the flange portion 113b of the valve stem member 113 moves away from the first seal member SL1, so that the plunger 135 of the solenoid valve EV is in the second position.

[0063] Immediately after the flange portion 113b of the valve shaft member 113 separates from the first seal member SL1, the internal pressure of the cylinder chamber CS is higher than the refrigerant pressure in the intermediate passage 22a. Therefore, in the second position, the pressure in the intermediate passage 22a is transmitted to the cylinder chamber CS via the outlet hole 2j, the small opening 2g, the through-hole 112a, the radial hole 112c, the circumferential groove 112b, the communication hole 2d, the pressure-equalizing chamber EC, the connecting hole 62d, and the blind hole 63. The refrigerant pressure in the cylinder chamber CS quickly decreases to approximately equal the pressure in the intermediate passage 22a (and the return passage 23). As a result, the force pressing down on the disk base 61 disappears, and the valve element 3 rises due to the biasing force of the biasing device 4 and seats on the valve seat 20. The biasing force of the biasing device 4 is transmitted to the piston member 6 via the actuation rod 5, displacing the piston member 6 to its upper position (FIG. 4). When the piston member 6 is displaced to the upper position, even if the diaphragm 83 is deformed downward, the resulting force is no longer transmitted to the operating rod 5, and therefore the valve body 3 can be placed in a forced closed state.

[0064] At this time, the end of the plunger 135 abuts against the second seal member SL2, preventing the refrigerant in the high-pressure chamber HS from passing through the through hole 112a and leaking into the intermediate passage 22a, without affecting the operation of the refrigeration cycle 100.

[0065] According to this embodiment, by interrupting the power supply to the solenoid valve EV, the cylinder chamber CS is connected to the intermediate passage 22a, thereby quickly reducing the internal pressure of the cylinder chamber CS, displacing the piston member 6 to an upward position and forcibly seating the valve body 3, thereby realizing the forced closing function of the expansion valve 1 regardless of the operation of the power element 8.

[0066] Furthermore, by supplying power to the solenoid valve EV, high-pressure refrigerant supplied from the condenser 102 is introduced into the cylinder chamber CS, thereby locking the piston member 6 in the lower position and ensuring the normal operation of the expansion valve 1. At this time, the refrigerant from the condenser 102 is introduced directly into the valve chamber VS without passing through the solenoid valve EV, thereby suppressing pressure loss and the like.

[0067] Furthermore, the second O-ring OR2 and third O-ring OR3, which are made of rubber or resin, support the piston member 6 with respect to the enlarged diameter hole 26 of the valve body 2. Therefore, even if vibration occurs in the piston member 6, the damping function of the second O-ring OR2 and third O-ring OR3 can suppress the vibration.

[0068] (Second embodiment) Fig. 5 is a schematic cross-sectional view showing an expansion valve 1A in a second embodiment in an open state, and schematically shows a refrigeration cycle 100A to which the expansion valve 1A is connected. Fig. 6 is a vertical cross-sectional view showing the expansion valve 1A in a closed state.

[0069] In this embodiment, the configuration of the piston member 6A and the fact that an electromagnetic valve is not provided are different from those of the first embodiment, but the other configurations are the same as those of the first embodiment, so the same symbols are used for the common configurations and redundant explanations will be omitted.

[0070] In the refrigeration cycle 100A of this embodiment, a branch pipe (pipe through which high-pressure refrigerant flows) DP is arranged, branching from the pipe leading from the condenser 102 to the valve chamber VS of the expansion valve 1A and leading to the pipe base 105A of the expansion valve 1A, and an on-off valve (valve device) VL is attached to the branch pipe DP. The on-off valve VL can selectively operate between an open position that opens the branch pipe DP and a closed position that closes it. The inflow path and the on-off valve VL constitute a supply section and a discharge section. The rest of the configuration is the same as that of the refrigeration cycle of the first embodiment.

[0071] The communication hole 2d connects the pressure equalizing chamber EC of the valve body 2A with the outer periphery of the end of the large opening 2Ae. A pipe base 105A is attached to the large opening 2Ae. The pipe base 105A is fixed to the valve body 2A by threading a male thread formed on the outer periphery of the pipe base 105A into a female thread formed on the inner periphery of the large opening 2Ae of the valve body 2A. A packing PK is disposed between the large opening 2Ae and the pipe base 105A to seal the gap between the pipe base 105A and the valve body 2A. This forms a high-pressure chamber HS between the pipe base 105A and the large opening 2Ae.

[0072] The pipe base 105A has a pipe section 105Aa that is connected to the branch pipe DP via an on-off valve VL. The high-pressure chamber HS communicates with the branch pipe DP via the internal flow path of the pipe base 105A and the pipe section 105Aa, and also communicates with the pressure-equalizing chamber EC via the communication hole 2d, but does not communicate with the valve chamber VS. The remaining configuration is the same as that of the expansion valve of the first embodiment.

[0073] The piston member 6A has a hole 6e that releases the pressure in the cylinder chamber CS downstream of the valve chamber VS. The hole 6e is formed, for example, in the shaft portion 62 of the piston member 6A. The hole 6e connects the blind hole 63 with the return flow path 23. The hole 6e is a hole that can sufficiently maintain the pressure in the cylinder chamber CS during normal use of the expansion valve 1A except when forced valve closure is performed, and is sized so that when forced valve closure is performed, the pressure in the cylinder chamber CS can be released through the hole 6e to quickly forcefully close the valve.

[0074] In this embodiment, one hole 6e is formed as an example, but the number of holes 6e is not limited to one and may be multiple. Furthermore, the shape of the hole 6e is, for example, a hole having a circular planar shape, but the shape of the hole 6e is not limited thereto. The hole 6e may be a slit, a long hole having a planar shape that is long in one direction, or the like.

[0075] Next, a description will be given of the forced valve closing operation of the expansion valve 1A using the on-off valve VL. Note that the on-off valve VL has a first position where it opens the branch pipe DP, and a second position where it closes the branch pipe DP.

[0076] When the on-off valve VL is in the first position (open position), the high-pressure refrigerant in the branch pipe DP is supplied to the high-pressure chamber HS via the pipe section 105Aa, and the pressure of the refrigerant in the high-pressure chamber HS is transmitted to the cylinder chamber CS via the communication hole 2d, making the internal pressure of the cylinder chamber CS high pressure.

[0077] When the cylinder chamber CS becomes high pressure, as described above, the piston member 6A is displaced to a lower position and locked by the locking member 85, allowing the operating rod 5 to move up and down in accordance with the operation of the power element 8.

[0078] On the other hand, when the on-off valve VL is in the second position (closed position), the high pressure of the refrigerant in the branch pipe DP is no longer transmitted to the high-pressure chamber HS, and some of the refrigerant in the cylinder chamber CS gradually flows out from the hole 6e formed in the shaft portion 62 into the return flow path 23. This reduces the internal pressure of the cylinder CS, displacing the piston member 6A to an upward position, and the valve element 3 can be placed in the closed state even if the power element 8 applies force to the operating rod 5 in the valve-opening direction.

[0079] According to this embodiment, by operating the on-off valve VL to the first position, high-pressure refrigerant supplied from the compressor 101 is introduced into the cylinder chamber CS, thereby displacing the piston member 6A to a lower position and ensuring the normal operation of the expansion valve 1. At this time, the refrigerant from the condenser 102 is introduced directly into the valve chest VS without passing through the on-off valve VL, thereby suppressing pressure loss and the like.

[0080] In contrast, by operating the on-off valve VL to the second position, the pressure in the cylinder chamber CS can be reduced, thereby displacing the piston member 6A to an upper position, thereby realizing the forced closing function of the expansion valve 1 regardless of the operation of the power element 8.

[0081] The on-off valve VL may be a three-way selector valve that selectively switches between a flow path connecting the branch pipe DP and the high-pressure chamber HS via the three-way selector valve and a flow path connecting the high-pressure chamber HS and the return flow path 23 (the inlet of the compressor 101). In this case, connecting the branch pipe DP and the high-pressure chamber HS via the three-way selector valve makes it possible to increase the internal pressure of the cylinder chamber CS, and the flow path connecting the high-pressure chamber HS and the return flow path 23 via the three-way valve makes it possible to quickly reduce the internal pressure of the cylinder chamber CS. According to this modification, there is no need to form a hole 6e in the piston member 6A, and the piston member 6 described in the first embodiment can be used.

[0082] In this example, an example has been described in which the flow path connecting the branch pipe DP and the high pressure chamber HS and the flow path connecting the high pressure chamber HS and the return flow path 23 (the inlet of the compressor 101) are switched via a three-way switching valve, but in other examples, a flow path connecting the high pressure chamber HS and the inlet side of the evaporator 103 may be used instead of the flow path connecting the high pressure chamber HS and the return flow path 23. The flow path connecting the high pressure chamber HS and the inlet side of the evaporator 103 may be, for example, a flow path connecting the high pressure chamber HS and the second flow path 22 or a flow path connecting the high pressure chamber HS and the intermediate passage 22a.

[0083] (Variation 1) FIG. 7 is a vertical cross-sectional view similar to FIG. 5 of an expansion valve 1B according to a modified example. In the expansion valve 1B of this embodiment, only the shape of the piston member 6B is different from that of the second embodiment; the other configurations are the same as those of the second embodiment, so the same symbols are used for common configurations and redundant explanations will be omitted.

[0084] The piston member 6B has a blind hole 63 formed by an enlarged diameter hole portion 64 on the upper side and a reduced diameter hole portion 65 on the lower side, and an auxiliary spring 66 is disposed within the enlarged diameter hole portion 64. The upper end of the auxiliary spring 66 abuts against the underside of the disk portion 84b of the stopper member 84, and its lower end abuts against the step between the enlarged diameter hole portion 64 and the reduced diameter hole portion 65, thereby urging the piston member 6B downward relative to the stopper member 84. The rest of the configuration of the piston member 6B, including the hole 6e, is the same as in the embodiment described above.

[0085] The piston member 6B moves between the upper and lower positions in response to changes in pressure in the cylinder chamber CS, but the pressure in the cylinder chamber CS may not rise quickly due to factors such as the viscosity of the refrigerant. In contrast, according to this modification, when the pressure in the cylinder chamber CS starts to rise, the auxiliary spring 66 biases the piston member 6B toward the lower position, thereby assisting the piston member 6B in quickly moving to the lower position.

[0086] According to this embodiment, the auxiliary spring 66 can assist in the axial expansion of the cylinder chamber CS. When the pressure difference between the cylinder chamber CS and the return flow path 23 is small, there is a risk that the force expanding the cylinder chamber CS may be insufficient, but by providing the auxiliary spring 66, it is possible to compensate for the force acting in the direction in which the cylinder chamber CS expands.

[0087] (Variation 2) Fig. 8 is a vertical cross-sectional view of an expansion valve 1C according to a modified example, similar to Fig. 5. Fig. 9 is an enlarged cross-sectional view showing a state immediately before the piston member 6C is assembled into the enlarged diameter hole 26C. In the expansion valve 1C of this embodiment, only the shape of the valve body 2C and the shape of the piston member 6C differ from the second embodiment, and the other configurations are the same as those of the second embodiment, so the same symbols are used for common configurations and redundant explanations will be omitted.

[0088] 9, in the valve body 2C, the expanded diameter hole 26C is formed by connecting, in this order, a first hole portion 26Ca at the lower end, a tapered hole portion 26Cb, a second hole portion 26Cc having a larger diameter than the first hole portion 26Ca, and a third hole portion 26Cd at the upper end, which is also larger in diameter than the second hole portion 26Cc. The inner diameter of the first hole portion 26Ca is D1. The upper end of the communication hole 2d opens into the second hole portion 26Cc.

[0089] A crimping groove 26Ce is formed adjacent to and above the third hole 26Cd. A crimping member 29C is fixed to the crimping groove 26Ce by crimping, preventing the second O-ring OR2 disposed in the third hole 26Cd from falling out. The rest of the configuration of the valve body 2B is the same as that of the above-described embodiment.

[0090] The shaft portion 62C of the piston member 6C has a first outer diameter portion 62Ca at the lower end, a reduced diameter portion 62Cc having a diameter smaller than that of the first outer diameter portion 62Ca, a tapered shaft portion 62Ce, and a second outer diameter portion 62Cd having a diameter larger than that of the first outer diameter portion 62Ca and extending to the disk base portion 61. A second circumferential groove 62Cb is formed in the first outer diameter portion 62Ca, and a third O-ring OR3 is disposed therein. The second outer diameter portion 62Cd has an outer diameter D2, and its inner diameter D1 is approximately equal to the outer diameter D2. That is, when the shaft portion 62C is fitted between the expanded diameter hole 26C, the inner diameter of the second O-ring OR2 is approximately equal to the outer diameter of the third O-ring OR3. Furthermore, the outer diameter of the third O-ring OR3 in its free state is smaller than the outer diameter of the second O-ring OR2 and the inner diameter of the second hole portion 26Cc.

[0091] In the above-described first embodiment and the like, when assembling the piston member 6 into the enlarged diameter hole 26, when the outer periphery of the third O-ring OR3 attached to the third circumferential groove 62b is moved to the assembly position while sliding against the inner wall of the enlarged diameter hole 26, there is a risk that the third O-ring OR3 may be damaged by the edge of the communicating hole 2d when passing through the inner wall of the enlarged diameter hole 26, and therefore careful assembly is required.

[0092] In contrast, according to this embodiment, the outer diameter of the third O-ring OR3 in a free state is smaller than the inner diameter of the second hole portion 26Cc in which the communicating hole 2d is formed. Therefore, as shown in FIG. 9, when the piston member 6C is assembled into the enlarged diameter hole 26C, the third O-ring OR3 is prevented from coming into contact with the communicating hole 2d, thereby suppressing damage thereto.

[0093] Furthermore, after assembly, as shown in FIG. 8, the inner diameter (D2) of the second O-ring OR2 engaged with the second outer diameter portion 62Cd is approximately equal to the outer diameter (D1) of the third O-ring OR3 engaged with the first hole portion 26Ca. Therefore, the pressure-receiving areas of the second O-ring OR2 and the third O-ring OR3 corresponding to the pressure in the pressure-equalizing chamber EC are equal to each other, thereby canceling the axial force applied to the piston member 6C. Note that any of the modified examples can be applied to the first embodiment.

[0094] (Third embodiment) An overview of a refrigeration system including an expansion valve according to the third embodiment will be described with reference to Fig. 10. Fig. 10 is a diagram schematically illustrating an example in which an expansion valve 1D according to the present embodiment is applied to a refrigeration cycle 100D.

[0095] 10, an expansion valve 1D, a compressor 101, a condenser 102, and an evaporator 103 are connected in a closed circuit via piping to form a refrigeration cycle. The upper space of a power element 308 of the expansion valve 1D is connected to a temperature sensing bulb 387 via a capillary tube 381.

[0096] An inlet passage 322 (described later) of the expansion valve 1D is connected to a primary pipe H1 on the condenser 102 side, a valve chamber VS (described later) of the expansion valve 1D is connected to a secondary pipe H2 on the evaporator 103 side, and an 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. Furthermore, a pressure equalizing pipe H5 connects the outlet-side pipe H3 of the evaporator 103 to the lower space of the power element of the expansion valve 1D.

[0097] The refrigerant compressed by the compressor 101 is supplied to the condenser 102 through high-pressure piping H4, where it is condensed and liquefied, and then supplied to the expansion valve 1D through primary piping H1. The expansion valve 1D reduces the pressure of the supplied refrigerant (expands it) and supplies it to the evaporator 103 through secondary piping H2. The evaporator 103 then evaporates the refrigerant, and the evaporated refrigerant returns to the compressor 101 through outlet piping H3 and is compressed again by the compressor 101. A temperature sensing bulb 387 is attached to the outlet piping H3 of the evaporator 103. The pressure in the outlet piping H3 of the evaporator 103 is transmitted to the lower space of the power element 308 of the expansion valve 1D through a pressure equalizing tube H5.

[0098] Fig. 11 is a longitudinal cross-sectional view of an external pressure equalizing expansion valve 1D according to the third embodiment, showing a state in which the solenoid valve EV is open. Fig. 12 is a longitudinal cross-sectional view of an external pressure equalizing expansion valve 1D according to the third embodiment, showing a state in which the solenoid valve EV is closed.

[0099] 11, the expansion valve 1D mainly comprises a valve body 302 having a valve chamber VS, a valve element 303, an urging device 304, an operating rod 305, a piston member 360, and a power element 308. The center line of the valve element 303 is defined as the axis L of the expansion valve 1D.

[0100] The cylindrical valve body 302 has an upper opening (communication hole) 332 extending along the axis L. The upper opening 332 has a first inner circumferential portion 332a that opens to the upper end of the valve body 302, a second inner circumferential portion 332b having a smaller diameter than the first inner circumferential portion 332a, a third inner circumferential portion 332c having a smaller diameter than the second inner circumferential portion 332b, and a fourth inner circumferential portion 332d having a smaller diameter than the third inner circumferential portion 332c.

[0101] A lateral opening 314 is formed in the center of the valve body 302, perpendicular to the axis L, and below the lateral opening 314, a lower opening 333 is formed along the axis L, opening to the lower end. A valve chamber VS is formed within the lower opening 333.

[0102] In the valve body 302, an introduction passage 322 is formed between the side opening 314 and the lower opening 333. The introduction passage 322 communicates with the valve chamber VS via an orifice passage 323. The inner periphery of the lower end of the orifice passage 323 forms the valve seat 320. The internal pressure of the orifice passage 323 is higher than the internal pressure of the valve chamber VS.

[0103] The inlet passage 322, which is a supply-side flow path, extends in a direction perpendicular to the paper surface and is connected to the primary pipe H1 (FIG. 10). In addition, the discharge-side flow path (not shown) connected to the valve chamber VS is connected to the secondary pipe H2 (FIG. 10), and the refrigerant that flows into the valve chamber VS through the valve seat 320 is discharged to the outside of the expansion valve through the discharge-side flow path.

[0104] The valve body 302 has a pressure equalizing opening 315a into which a pressure equalizing pipe H5 (FIG. 10) is fitted and fixed by brazing or the like. The pressure equalizing opening 315a communicates with the bottom of a bypass passage 314d (described later) via a through-hole 315b connected to the bottom of the pressure equalizing opening 315a, and the bypass passage 314d communicates with a lower space (low-pressure space) LC of a power element 308 (described later) via a pressure equalizing passage 315c.

[0105] Figure 13 is an enlarged cross-sectional view showing the periphery of side opening 314. In Figure 13, side opening 314 has large opening 314a, crimped groove 314b, small opening 314c with a smaller diameter than large opening 314a, and bypass path 314d with a smaller diameter than small opening 314c, along axis O perpendicular to axis L. The lower end of fourth inner peripheral portion 332d communicates with the inner periphery of small opening 314c. The bottom of large opening 314a and introduction path 322 communicate with inlet hole 312h.

[0106] A valve seat member 312 is disposed within the small opening 314c. The valve seat member 312 comprises a cylindrical shaft portion 312g and a circular flange portion (also simply referred to as the flange portion) 312e, which are connected together. One end (the rear end) of the valve seat member 312 abuts against the step 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 302 radially inward. An O-ring OR is provided between the circular flange portion 312e and the valve body 302 to seal the gap between them.

[0107] The valve seat member 312 further has a circular through-hole (also referred to as a "through hole") 312a extending along the axis O, 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. The circumferential groove 312b communicates with the fourth inner circumferential portion 332d. The circumferential groove 312b and the radial hole 312c form a relay passage.

[0108] The cylindrical valve stem member 313 has a long stem portion (also simply referred to as a stem portion) 313a inserted so as to pass through the circular through-hole 312a of the valve seat member 312, a flange portion 313b having a diameter larger than that of the circular through-hole 312a, and a short stem portion 313c. The surface of the flange portion 313b facing the circular through-hole 312a is tapered to improve sealing performance when it abuts against the circular through-hole 312a. A gap is provided between the outer periphery of the long stem portion 313a and the inner periphery of the circular through-hole 312a through which the refrigerant can pass, and the valve stem member 313 is movable relative to the valve seat member 312 in the direction of the axis O.

[0109] 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 large opening 314a with respect to the bottom of the bypass passage 314d.

[0110] The solenoid valve EV has the same configuration as the embodiment described above, and therefore the same reference numerals are used to avoid redundant description. However, it differs in that a ball 135e is disposed at the tip of the plunger 135, and a pressure equalizing path 135d is provided between the plunger 135 and the suction element 140 to supply refrigerant from the high-pressure chamber HS. The coil, yoke, housing, and mounting bolts are not shown in the drawings.

[0111] 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 312h and can also communicate with the circular through hole 312a of the valve seat member 312.

[0112] 11, the valve disc 303 is disposed within the valve chamber VS. The valve disc 303 comprises a valve disc portion 303a having tapered upper and lower ends, and a guide portion 303b connected together. The upper and lower ends of the guide portion 303b abut against the inner periphery of the valve chamber VS, allowing the valve disc 303 to slide in the direction of the axis L while maintaining its orientation.

[0113] When the tapered portion of the head of the valve element 303 is seated on the valve seat 320, the flow of refrigerant passing through the orifice passage is restricted. This state is called a non-communicating state. However, even when the valve element 303 is seated on the valve seat 320, a limited amount of refrigerant may still flow. On the other hand, when the valve element 303 is separated from the valve seat 320, the flow of refrigerant passing through the orifice passage increases. This state is called a communicating state.

[0114] The biasing device 304 includes a coil spring 341 made of a spirally wound wire rod with a circular cross section, a retaining plate 342 with a bowl-shaped recessed upper surface that supports the lower end of the valve body portion 303a, a spring receiving member 344, and a cap 345.

[0115] The spring receiving member 344 is fixed to the lower end of the valve body 302 by threading the male thread formed on the outer periphery into the female thread formed on the lower end of the valve body 302 .

[0116] The upper end of the coil spring 341 abuts against the lower outer surface of the holding plate 342, and the lower end of the coil spring 341 is held by a spring receiving member 344, so that the coil spring 341 biases them in a direction separating them from each other.

[0117] After the coil spring 341 has been screwed, the cap 345 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 344.

[0118] Three actuating rods 305 (only two are shown in FIGS. 11 and 12 ) are arranged circumferentially at equal angular phases around the valve disc 303, and are slidably inserted into openings (not shown) in the valve body 302, extending parallel to the axis L. The lower ends of the actuating rods 305 abut against the upper surface of a guide portion 303b of the valve disc 303. The upper ends of the actuating rods 305 abut against the lower surface of a disk base 361 of a piston member 360 (described later).

[0119] The actuating rod 305 can press the valve element 303 in the valve opening direction against the biasing force of the biasing device 304. When the actuating rod 305 moves downward, the valve element 303 moves away from the valve seat 320, and the expansion valve 1D enters the open state.

[0120] Next, a description will be given of the power element 308. The power element 308 has an upper cover member 382, ​​a diaphragm 383, a receiving member 386, and a stopper member 384.

[0121] The upper cover member 382 is formed by, for example, press-forming a metal plate. The upper cover member 382 has a flattened dome shape with a raised center, and a through-hole 382a is formed in the center. The lower end of the capillary tube 381 is fixed to the opening 382a by brazing or welding.

[0122] Receiving member 386, which faces upper cover member 382, ​​is formed, for example, by press-forming a metal plate. Receiving member 386 has an annular lower flange portion 386a and a cylindrical portion 386b that is connected to the inner periphery of lower flange portion 386a and faces downward. A female thread 386c is formed on the inner periphery of cylindrical portion 386b.

[0123] Diaphragm 383, which is disposed between top cover member 382 and receiving member 386, is made of a thin, flexible metal (e.g., SUS) plate, and has approximately the same outer diameter as top cover member 382 and receiving member 386. Diaphragm 383 has a concentrically formed uneven shape, and has a flexible structure.

[0124] Stopper member 384 is made up of a disk portion 384b and a circular pipe portion 384c connected together, with the inside of circular pipe portion 384c forming a cylindrical recess 384a. A thin-walled cylindrical caulking portion for attaching an annular locking member 385 is formed at the lower end of circular pipe portion 384c.

[0125] Piston member 360 is made up of a disk base 361 at the upper end and a shaft 362 at the lower end, which are coaxially connected, and has a through-hole 363 extending from the upper end to the lower end. Disk base 361 is housed in a cylindrical recess 384a of a stopper member 384 of power element 308. A first circumferential groove 361a is formed on the outer periphery of disk base 361, and an O-ring OR4 is disposed therein to provide a seal between cylindrical recess 384a and disk base 361.

[0126] After inserting the disk base 361 of the piston member 360 into the cylindrical recess 384a, the locking member 385 is brought into contact with the inner circumferential step at the bottom end of the circular pipe portion 384c, and the crimping portion disposed on the outer periphery of the locking member 385 is crimped radially inward, thereby attaching the locking member 385 to the bottom end of the circular pipe portion 384c. This prevents the disk base 361 from coming off the stopper member 384.

[0127] The disk base 361 is movable in the axial direction between an upper position (FIG. 12) where its upper end abuts against the lower surface of the disk portion 384b, and a lower position (FIG. 11) where its lower end abuts against the upper surface of the locking member 385. With the disk base 361 fixed in the lower position, the distance along the axis L from the upper end of the stopper member 384 to the lower end of the operating rod 305 is a specified value at which the expansion valve 1D is operable.

[0128] The lower end of the shaft portion 362 is slidably inserted into the third inner circumferential portion 332c of the valve body 302, and an O-ring OR5 disposed around the shaft portion 362 seals the gap between the shaft portion 362 and the second inner circumferential portion 332b. The O-ring OR5 is held in place by a cylindrical retaining member 330 that is press-fit into the first inner circumferential portion 332a.

[0129] Here, the space between the disk portion 384b and the disk base portion 361 is referred to as a cylinder chamber CS. The cylinder chamber CS communicates only with the through hole 363. The through hole 363 communicates with the fourth inner peripheral portion 332d via the third inner peripheral portion 332c.

[0130] (Expansion valve operation) An example of the operation of the expansion valve 1D will be described with reference to Figure 10. The refrigerant pressurized by the compressor 101 is supplied to the condenser 102 via high-pressure piping H4, where it is condensed and liquefied, and then sent to the expansion valve 1D via primary piping H1. The refrigerant adiabatically expanded by the expansion valve 1D is sent to the evaporator 103 via secondary piping H2, where it exchanges heat with the air flowing around it. The refrigerant is then returned from the evaporator 103 to the compressor 101 via outlet piping H3.

[0131] At this time, the pressure of the refrigerant in the outlet pipe H3 is transmitted via the pressure equalizing pipe H5 to the pressure equalizing path 315c of the expansion valve 1D, and then transmitted to the lower space LC of the power element 8. Meanwhile, the temperature of the refrigerant in the outlet pipe H3 is transmitted to the temperature sensing bulb 387, causing the gas-liquid state and pressure of the gas in the temperature sensing bulb 387 to change, and this is transmitted via the capillary tube 381 to the upper space UC of the power element 308. The diaphragm 383 is displaced vertically due to the pressure difference between the upper space UC and the lower space LC.

[0132] The high-pressure refrigerant from the condenser 102 is supplied through an inlet passage 322 to the expansion valve 1D.

[0133] Assume that the solenoid valve EV is in an open state, as shown in FIG. 11. In this state, the pressure of the refrigerant in the high-pressure chamber HS is transmitted from the through-hole 312a of the valve seat member 312 through the radial hole 312c, the circumferential groove 312b, the fourth inner circumferential portion 332d, the third inner circumferential portion 332c, and the through-hole 363 to the cylinder chamber CS, causing the internal pressure of the cylinder chamber CS to increase. As a result, the piston member 360 is pressed downward against the stopper member 384, maintaining the stopper member 384 and the operating rod 305 spaced a predetermined distance apart in the axial direction. This allows the expansion valve 1D to perform its intended operation.

[0134] When the valve element 303 is seated on the valve seat 320 (in a non-communicating state), the flow rate of the refrigerant sent from the introduction passage 322 through the valve chamber VS to the evaporator 103 is restricted. On the other hand, when the valve element 303 is separated from the valve seat 320 (in a communicating state), the flow rate of the refrigerant sent from the introduction passage 322 through the valve chamber VS to the evaporator 103 increases. The expansion valve 1D is switched between a closed state and an open state by transmitting a driving force between the stopper member 384 and the valve element 303 by the piston member 360 and the operating rod 305.

[0135] When the internal pressure of the upper space UC decreases relative to the internal pressure of the lower space LC, the diaphragm 383 rises, and the valve disc 303 moves upward together with the stopper member 384, piston member 360, and operating rod 305 in accordance with the biasing force of the coil spring 341. 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 383, stopper member 384, and piston member 360 are pressed downward, and the operating rod 305 moves downward, pressing down the valve disc 303. In this way, the expansion valve 1D is switched between the open state and the closed state.

[0136] Furthermore, when the flow rate of the refrigerant sent from the expansion valve 1D to the evaporator 103 changes, the temperature and pressure of the refrigerant flowing in the outlet pipe H3 also change. The internal pressure of the lower space LC and the upper space UC changes accordingly, and this changes the amount of drive of the working rod 305 by the power element. In other words, the expansion valve 1D automatically adjusts the amount of refrigerant supplied from the expansion valve 1D to the evaporator 103 according to the temperature and pressure of the refrigerant returning from the evaporator 103 to the expansion valve 1D.

[0137] (Expansion valve forced closing operation) Next, a forced valve closing operation of the expansion valve 1D using the solenoid valve EV will be described. In the solenoid valve EV, a position where the ball 135e of the plunger 135 presses the exposed end of the valve stem member 313 and abuts against the valve seat member 312 is defined as a second position, and a position where the ball 135e of the plunger 135 is separated from the valve stem member 313 and the valve seat member 112 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 302 from the introduction path 322 via an inlet hole 312h.

[0138] 11, when power is supplied to the coil from an external power supply device, 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 136. As a result, the ball 135e of the plunger 135 moves away from one end of the circular through-hole 312a, while the flange portion 313b of the valve shaft member 313 abuts against the other end of the circular through-hole 312a due to the urging force of the compression spring 316, and the plunger 135 of the solenoid valve EV is in the first position.

[0139] 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, the fourth inner circumferential portion 332d, the third inner circumferential portion 332c, and the through-hole 363 to the cylinder chamber CS, maintaining the internal pressure of the cylinder chamber CS at a high pressure. Meanwhile, because the flange portion 313b covers the other end of the circular through-hole 312a, leakage of refrigerant from the high-pressure chamber HS through the circular through-hole 312a and the bypass path 314d to the pressure equalizing opening 315a side is suppressed, and the internal pressure of the cylinder chamber CS remains high.

[0140] The side of piston member 360 opposite cylinder chamber CS across disk base 361 faces lower space LC, through which low-pressure refrigerant passes. When cylinder chamber CS becomes high-pressure, the piston member 360 receives a force in the direction of expanding cylinder chamber CS due to the pressure difference with the refrigerant pressure in lower space LC, and piston member 360 is displaced away from power element 308 to a lower position where it is locked by locking member 385. When piston member 360 is locked in the lower position, the axial length from the upper end of stopper member 384 to the lower end of operating rod 305 becomes a specified value, and therefore operating rod 305 can move up and down in response to the operation of power element 308.

[0141] 12, when power is not supplied to the coil from an external power supply device, the ball 135e of the plunger 135 is urged and moves in a direction approaching the valve seat member 312 by the urging force of the compression coil spring 136. As a result, the ball 135e of the plunger 135 abuts against one end of the through hole 312a to block it, and at the same time, the ball 135e presses the end of the exposed long shaft portion 313a of the valve shaft member 313 against the urging force of the compression spring 316 to displace it toward the bypass path 314d, thereby separating the flange portion 313b from the other end of the through hole 312a, and the plunger 135 of the solenoid valve EV is in the second position.

[0142] Immediately after the flange portion 313b of the valve shaft member 313 opens the circular through-hole 312a, the internal pressure of the cylinder chamber CS is higher than the pressure of the refrigerant in the lower space LC. Therefore, in the second position, the pressure in the pressure equalizing opening 315a is transmitted to the cylinder chamber CS via the through-hole 315b, the bypass path 314d, the circular through-hole 312a, the radial hole 312c, the circumferential groove 312b, the fourth inner circumferential portion 332d, the third inner circumferential portion 332c, and the through-hole 363. The refrigerant pressure in the cylinder chamber CS quickly decreases to approximately equal the pressure in the pressure equalizing opening 315a (piping H5). As a result, the force pressing down on the disk base 361 disappears, and the valve disc 303 rises due to the biasing force of the biasing device 304 and seats on the valve seat 320. The biasing force of the biasing device 304 is transmitted to the piston member 360 via the operating rod 305, and the piston member 360 is displaced to the upper position (FIG. 12). When the piston member 360 is displaced to the upper position, even if the diaphragm 383 is deformed downward, the resulting force is no longer transmitted to the operating rod 305, and therefore the valve body 303 can be placed in a forced valve-closed state.

[0143] Furthermore, since the ball 135e of the plunger 135 abuts against and shields the end of the through hole 312a, the refrigerant in the high-pressure chamber HS is prevented from passing through the through hole 312a and leaking into the pipe H5, and the operation of the refrigeration cycle 100D is not affected.

[0144] (Variation) Fig. 14 is a vertical cross-sectional view of an expansion valve 1E according to a modified example, similar to Fig. 11. Fig. 15 is a vertical cross-sectional view of an expansion valve 1E according to a modified example, similar to Fig. 12. In the expansion valve 1E of this embodiment, only the shape of the valve body 302E is different from that of the third embodiment; the other configurations are the same as those of the third embodiment, so the same symbols are used for common configurations and redundant explanations will be omitted.

[0145] The valve body 302E of this modification differs in that the bypass passage 314d does not communicate with the pressure equalizing opening 315a to which the pipe H5 is connected, but instead communicates with the valve chest VS via a vertical hole (also referred to as a communication opening) 315E extending parallel to the axis L. The valve chest VS is connected to the secondary pipe H2 (FIG. 10) via a discharge-side flow path (not shown). The rest of the configuration is the same as in the third embodiment.

[0146] (Expansion valve forced closing operation) The operation of the expansion valve 1E is similar to that of the third embodiment. In this modification as well, high-pressure refrigerant is supplied to the high-pressure chamber HS between the base 120 and the valve body 302 from the introduction path 322 via the inlet hole 312h.

[0147] 14, when power is supplied to the coil from an external power supply device, 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 136. As a result, the ball 135e of the plunger 135 moves away from one end of the circular through-hole 312a, while the flange portion 313b of the valve shaft member 313 abuts against the other end of the circular through-hole 312a due to the urging force of the compression spring 316, and the plunger 135 of the solenoid valve EV is in the first position.

[0148] In the first position, as in the third embodiment, the refrigerant pressure in the high-pressure chamber HS is transmitted from the through-hole 312a of the valve seat member 312 through the radial hole 312c, the circumferential groove 312b, the fourth inner circumferential portion 332d, the third inner circumferential portion 332c, and the through-hole 363 to the cylinder chamber CS, maintaining a high pressure inside the cylinder chamber CS. Meanwhile, because the flange portion 313b covers the other end of the through-hole 312a, leakage of refrigerant from the high-pressure chamber HS through the through-hole 312a and the vertical hole 315E to the valve chamber VS is suppressed, and the internal pressure of the cylinder chamber CS remains high. This ensures proper operation of the expansion valve 1E.

[0149] 15, when power is not supplied to the coil from an external power supply device, the ball 135e of the plunger 135 is urged and moves in a direction approaching the valve seat member 312 by the urging force of the compression coil spring 136. As a result, the ball 135e of the plunger 135 abuts against one end of the through hole 312a to block it, and at the same time, the ball 135e presses the exposed end of the long shaft portion 313a of the valve shaft member 313 against the urging force of the compression spring 316, displacing it toward the bypass path 314d, thereby moving the flange portion 113b away from the other end of the through hole 312a, and the plunger of the solenoid valve EV is in the second position.

[0150] In the second position, the pressure in the valve chamber VS is transmitted to the cylinder chamber CS via the vertical hole 315E, the bypass passage 314d, the through-hole 312a, the radial hole 312c, the circumferential groove 312b, the fourth inner circumferential portion 332d, the third inner circumferential portion 332c, and the through-hole 363, and the refrigerant pressure in the cylinder chamber CS quickly decreases to approximately equal to the pressure in the valve chamber VS. As a result, the force pressing down on the disk base 361 disappears, and the valve disc 303 is raised by the biasing force of the biasing device 304 and seats on the valve seat 320. The biasing force of the biasing device 304 is transmitted to the piston member 360 via the operating rod 305, and the piston member 360 is displaced to the upper position. When the piston member 360 is displaced to the upper position, even if the diaphragm 383 is deformed downward, the resulting force is no longer transmitted to the operating rod 305, and therefore the valve body 303 can be placed in a forced closed state.

[0151] Furthermore, since the ball 135e of the plunger 135 abuts against and shields the end of the through hole 312a, the refrigerant in the high-pressure chamber HS is prevented from leaking through the through hole 312a and the vertical hole 315E into the valve chamber VS, and the operation of the refrigeration cycle is not affected.

[0152] (Other variations) The present invention is not limited to the above-described embodiments, and it goes without saying that the present invention also includes design changes that do not deviate from the spirit of the present invention.

[0153] For example, in the second embodiment, an example has been described in which the on-off valve VL is provided in the external flow path outside the valve main body 2A, but the on-off valve VL may also be provided in an inflow path formed in the valve main body 2A.

[0154] Alternatively, the hole 6e may be formed in the disk base 61.

[0155] Furthermore, instead of forming the hole 6e, it is also possible to use a piston member 6F that does not include at least one of the O-rings OR1 and OR2, as in the expansion valve 1F that is a modification of the second embodiment shown in Fig. 16. In this modification, since no O-ring is used, pressure can be exhausted from the cylinder chamber CS through the gap between the valve body 2A and the piston member 6F.

[0156] The gap between the valve body 2A and the portion of the piston member 6F where the omitted O-ring was located is left as a small gap, and the refrigerant flows out through this small gap, thereby forcing the valve to close. The small gap here does not hinder the movement of the piston member 6F, can maintain sufficient pressure in the cylinder chamber CS during normal use other than when forcibly closing the valve, and can smoothly forcibly close the valve by venting the pressure in the cylinder chamber CS through this gap when forcibly closing the valve. Note that although the modified example in Figure 16 shows an example in which both O-rings are omitted, it is also possible to omit only one of the O-rings.

[0157] 17 shows an expansion valve 1G as a modification of the second embodiment. The expansion valve 1G is a modification that releases pressure from the cylinder chamber CS downstream of the valve chamber VS and upstream of the evaporator 103.

[0158] Specifically, the pocket hole 63 of the piston member 6G has an opening at a position that avoids the pressure equalizing chamber EC. As an example, the piston member 6G has a small-diameter opening 67 at its tip that is coaxial with the pocket hole 63. The small-diameter opening 67 communicates with a linear groove 68 that is formed at the lower end of the piston member 6G that abuts against the upper end of the actuation rod 5 and extends in a direction perpendicular to the axis. Furthermore, the piston member 6G does not have the hole 6e of the second embodiment. Other than that, the configuration of the piston member 6G is the same as that of the second embodiment.

[0159] Meanwhile, a pressure relief passage 2s communicating with the intermediate passage 22a is formed in the bottom surface of the enlarged diameter hole 26 in the valve body 2G. With this configuration, the high pressure in the cylinder chamber CS is discharged into the enlarged diameter hole 26 through the small diameter opening 67 and the linear groove 68 of the piston member 6G, and then passed through the pressure relief passage 2s and the intermediate passage 22a to the second flow path 22. The rest of the configuration is the same as in the embodiment shown in Fig. 5, so repeated explanations will be omitted.

[0160] In another variation of this variation, there is an example in which the minute gap between the actuating rod 5 and the central hole 28 of the valve body 2G is used as a flow path for exhausting pressure. In this other variation, no new flow path is created in the bottom surface of the enlarged diameter hole 26. The minute gap here does not hinder the movement of the piston member, can sufficiently maintain the pressure in the cylinder chamber CS during normal use other than when the valve is forcibly closed, and can smoothly and forcibly close the valve by exhausting the pressure in the cylinder chamber CS through this gap when the valve is forcibly closed.

[0161] Furthermore, as a modification of the second embodiment, a dedicated flow path and an on-off valve may be used to exhaust pressure from the cylinder chamber CS.

[0162] In the expansion valve 1H of the modified example shown in Fig. 18, a discharge passage EX is formed that connects the pressure equalizing chamber EC in the valve body 2H with the outside, and the outer end of this discharge passage EX is connected to the inlet side of the evaporator 103 via a second on-off valve (second valve device) VL2 and a pipe (also referred to as an external flow path portion) HT. In this modified example, the discharge passage EX is included in the outflow path. The other configurations are the same as those of the embodiment shown in Fig. 5 except that the piston member 6A does not have the hole 6e, so duplicated explanations will be omitted.

[0163] In the expansion valve 1H, high-pressure refrigerant is introduced into the pressure-equalizing chamber EC by opening the on-off valve VL while closing the second on-off valve VL2. On the other hand, by opening the second on-off valve VL2 while closing the on-off valve VL, the refrigerant flows from the pressure-equalizing chamber EC through the discharge passage EX and the pipe HT to the evaporator 103.

[0164] In the expansion valve 1I of the modified example shown in Fig. 19, a second on-off valve VL2 is disposed midway in the pipe HT that connects the pipe section 105Aa and the inlet side of the evaporator 103. The other configurations are the same as those of the embodiment shown in Fig. 5 except that the piston member 6A does not have the hole 6e, and therefore redundant explanations will be omitted.

[0165] 19, by opening the on-off valve VL while closing the second on-off valve VL2, high-pressure refrigerant is introduced into the pressure-equalizing chamber EC via the high-pressure chamber HS. On the other hand, by opening the second on-off valve VL2 while closing the on-off valve VL, refrigerant flows from the pressure-equalizing chamber EC through the high-pressure chamber HS and the pipe HT to the evaporator 103.

[0166] As a further modification, a second valve device VL2 may be provided in an outlet passage formed in the valve body.

[0167] The actuating rod and the piston member may be integral. "Integrated" here means that the actuating rod and the piston member are formed from a single member. The actuating rod and the piston member may be separate members, or may be fixed together.

[0168] This specification includes the disclosure of the following inventions. (First form) a valve body having a valve chamber and a valve seat; a valve body disposed in the valve chamber; a power element provided in the valve body and generating a force to separate the valve element from the valve seat and open the valve; a first biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and driving the valve element; a piston member that, together with the power element, defines a cylinder chamber that is extendable and contractible in the direction of movement of the valve body and that transmits force generated by the power element to the actuation rod; a supply unit that supplies the refrigerant in the valve chamber or the refrigerant upstream of the valve chamber to the cylinder chamber; An expansion valve characterized by:

[0169] (Second form) The expansion valve of a first embodiment is characterized by comprising a discharge part that discharges the pressure in the cylinder chamber downstream of the valve chamber.

[0170] (Third Form) The supply unit includes: an inlet passage formed in the valve body, through which the refrigerant in the valve chamber or the refrigerant upstream of the valve chamber flows into the cylinder chamber; a first valve device provided in the inlet passage and configured to control the inflow of the refrigerant into the cylinder chamber; Equipped with the discharge portion includes an outflow path through which the refrigerant in the cylinder chamber flows downstream of the valve chamber, the outflow channel includes a part of the inflow channel and a branch channel branching from the part and communicating the part with a downstream side of the valve chest, The first valve device also serves as a second valve device and is configured to be switchable between a state in which the inflow passage is opened and the outflow passage is closed, and a state in which the outflow passage is opened and the inflow passage is closed. An expansion valve according to a third embodiment, characterized in that:

[0171] (Fourth Form) The inlet channel is a first hole formed in the valve body, in which a portion of the piston member on the valve chamber side is disposed; a second hole formed in the piston member and communicating with the first hole and the cylinder chamber; a first flow path portion formed in the valve body and communicating with the valve chamber or an upstream side of the valve chamber; a second flow path portion formed in the valve body and communicating with the first hole; a connecting chamber formed in the valve body and connected to the first flow path portion and the second flow path portion; Equipped with The outflow channel is the second flow path portion, the connection chamber, and a third flow path portion that communicates the downstream side of the valve chamber with the connection chamber, The connecting chamber is a first communication flow path that connects the first flow path portion and the second flow path portion; a second communication flow path that communicates the second flow path portion and the third flow path portion; Equipped with the first valve device includes a valve stem member disposed in the connection chamber and a drive device that drives the valve stem member, The valve stem member is formed to be movable between a first position where the first flow path portion and the second flow path portion are communicated with each other via the first communication flow path of the connection chamber, and both the first flow path portion and the second flow path portion are not communicated with the third flow path portion, and a second position where the second flow path portion and the third flow path portion are communicated with each other via the second communication flow path of the connection chamber, and both the second flow path portion and the third flow path portion are not communicated with the first flow path portion. A fourth form expansion valve characterized by:

[0172] (Fifth Form) The drive device is a drive unit provided in the valve body, the drive unit having a plunger and configured to move the valve stem member from one of the first position and the second position to the other by the plunger; a second biasing device provided in the connection chamber and biasing the valve shaft member from the other side toward the one side; An expansion valve according to a fourth aspect, comprising:

[0173] (Sixth form) a valve seat member disposed in the connecting chamber between an opening of the first flow path portion and an opening of the third flow path portion, preventing a flow of refrigerant from the first flow path portion to the third flow path portion, covering the opening of the second flow path portion, and having a gap between itself and the opening of the third flow path portion; the valve seat member has a through hole penetrating in the movement direction of the plunger, and a relay path relaying the through hole and the opening of the second flow path portion, The valve shaft member includes a shaft portion that is disposed within the through hole, is formed to be movable in the axial direction of the through hole, and forms a flow path between the shaft portion and the inner surface of the through hole; and a flange portion that is provided on the shaft portion, is disposed in the gap, and abuts against the valve seat member to disconnect the opening of the through hole from the connection chamber. Equipped with a tip end surface of the plunger that abuts against the valve stem member to form a surface that disconnects the opening of the through hole from the connection chamber; An expansion valve according to a fifth aspect, characterized in that:

[0174] (7th form) a periphery of the opening of the through hole on an end surface of the valve seat member on the third flow path portion side is formed by a first seal member, a second seal member is formed around the opening of the through hole on the end surface of the valve seat member facing the drive unit; An expansion valve according to a sixth aspect, characterized in that:

[0175] (8th form) the piston member has a base portion disposed within a stopper member of the power element and constituting the cylinder chamber together with the stopper member, and a piston member shaft portion; the valve body has a hole in which the piston member shaft is disposed, and a flow path portion communicating with the hole and through which the refrigerant flows, The piston member shaft is supported in the hole via a pair of O-rings, the pair of O-rings are disposed on both sides in the axial direction of the piston member shaft portion, sandwiching the opening of the flow path portion in the hole; a pressure equalizing space is formed by the inner surface of the hole, the pair of O-rings, and the piston member shaft portion; When the pair of O-rings are attached to the piston member and assembled to the valve body, the inner diameter of one O-ring is approximately the same as the outer diameter of the other O-ring, or the outer diameter of one O-ring is approximately the same as the outer diameter of the other O-ring. The expansion valve according to any one of the first to seventh embodiments, characterized in that:

[0176] (9th form) The supply unit includes: an inflow passage provided in the valve body and connected to an external flow passage portion upstream of the valve chamber outside the valve body, for allowing the refrigerant upstream of the valve chamber to flow into the cylinder chamber; a valve device provided in the inflow passage or the external flow passage portion, which controls the inflow of the refrigerant into the cylinder chamber via the inflow passage; The expansion valve according to any one of the first to eighth embodiments, comprising:

[0177] (10th form) The discharge section is an outflow path provided in the valve body and connected to an external flow path portion downstream of the valve chamber outside the valve body, for allowing the refrigerant in the cylinder chamber to flow downstream of the valve chamber via the external flow path portion; a valve device provided in the outflow path or the external flow path portion, which controls the outflow of the refrigerant in the cylinder chamber to a downstream side of the valve chamber via the outflow path; An expansion valve according to a second embodiment, comprising:

[0178] (11th form) the valve body has a low-pressure flow path through which a refrigerant having a pressure lower than that in the valve chamber flows, The power element is a housing fixed to the valve body; a diaphragm provided in the housing and dividing the interior of the housing into a pressure actuated chamber and a valve chamber side chamber communicating with the low-pressure flow path; a stopper member disposed in the valve-chamber side chamber and having the piston member disposed therein; Equipped with the cylinder chamber is formed by the stopper member and the piston member, a stopper portion provided on the stopper member and the piston member to prevent the piston member from moving beyond a predetermined position relative to the stopper member toward the valve chamber; The expansion valve according to any one of the first to tenth embodiments, comprising: [Explanation of symbols]

[0179] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I: Expansion valve 2, 2A, 2B, 2C, 2G, 2H, 302, 302E: Valve body 3, 303: Valve body 4, 304: Actuating device 5, 305: Operating rod 6, 6B, 6C, 6F, 360: Piston parts 8, 308: Power Element 20, 320: Valve seat 140: Attractor 135: Plunger 132: Coil EV: Solenoid valve VS: Valve chamber VL: On-off valve CS: Cylinder chamber HS: Hyperbaric chamber

Claims

1. a valve body having a valve chamber and a valve seat; a valve body disposed in the valve chamber; a power element provided in the valve body and generating a force to separate the valve element from the valve seat and open the valve; a first biasing device that biases the valve body toward the valve seat; an actuation rod provided in the valve body and driving the valve element; a piston member that, together with the power element, defines a cylinder chamber that is extendable and contractible in the direction of movement of the valve body and that transmits force generated by the power element to the actuation rod; a supply unit that supplies the refrigerant in the valve chamber or the refrigerant upstream of the valve chamber to the cylinder chamber; An expansion valve characterized by:

2. 2. The expansion valve according to claim 1, further comprising a discharge portion that discharges pressure in the cylinder chamber downstream of the valve chamber.

3. The supply unit includes: an inlet passage formed in the valve body, through which the refrigerant in the valve chamber or the refrigerant upstream of the valve chamber flows into the cylinder chamber; a first valve device provided in the inlet passage and configured to control the inflow of the refrigerant into the cylinder chamber; Equipped with the discharge portion includes an outflow path through which the refrigerant in the cylinder chamber flows downstream of the valve chamber, the outflow channel includes a part of the inflow channel and a branch channel branching from the part and communicating the part with a downstream side of the valve chest, the first valve device also serves as a second valve device and is configured to be switchable between a state in which the inflow passage is opened and the outflow passage is closed, and a state in which the outflow passage is opened and the inflow passage is closed.

3. The expansion valve according to claim 2.

4. The inlet channel is a first hole formed in the valve body, in which a portion of the piston member on the valve chamber side is disposed; a second hole formed in the piston member and communicating with the first hole and the cylinder chamber; a first flow path portion formed in the valve body and communicating with the valve chamber or an upstream side of the valve chamber; a second flow path portion formed in the valve body and communicating with the first hole; a connecting chamber formed in the valve body and connected to the first flow path portion and the second flow path portion; Equipped with The outflow channel is the second flow path portion, the connection chamber, and a third flow path portion that communicates the downstream side of the valve chamber with the connection chamber, The connecting chamber is a first communication flow path that communicates the first flow path portion and the second flow path portion; a second communication flow path that communicates the second flow path portion and the third flow path portion; Equipped with the first valve device includes a valve stem member disposed in the connection chamber and a drive device that drives the valve stem member, The valve shaft member is formed to be movable between a first position in which the first flow path portion and the second flow path portion are communicated with each other via the first communication flow path of the connection chamber, and both the first flow path portion and the second flow path portion are not communicated with the third flow path portion, and a second position in which the second flow path portion and the third flow path portion are communicated with each other via the second communication flow path of the connection chamber, and both the second flow path portion and the third flow path portion are not communicated with the first flow path portion.

4. The expansion valve according to claim 3.

5. The drive device is a drive unit provided on the valve body, the drive unit having a plunger and configured to move the valve stem member from one of the first position and the second position to the other by the plunger; a second biasing device provided in the connecting chamber and biasing the valve shaft member from the other side toward the one side; The expansion valve according to claim 4, further comprising:

6. a valve seat member disposed in the connecting chamber between an opening of the first flow path portion and an opening of the third flow path portion, preventing a flow of the refrigerant from the first flow path portion to the third flow path portion, covering the opening of the second flow path portion, and having a gap between itself and the opening of the third flow path portion; the valve seat member has a through hole penetrating in the movement direction of the plunger, and a relay path relaying the through hole and the opening of the second flow path portion, The valve shaft member includes a shaft portion that is disposed within the through hole, is formed to be movable in the axial direction of the through hole, and forms a flow path between the shaft portion and the inner surface of the through hole; and a flange portion that is provided on the shaft portion, is disposed in the gap, and abuts against the valve seat member to disconnect the opening of the through hole from the connection chamber. Equipped with a tip end surface of the plunger that abuts against the valve stem member to form a surface that disconnects the opening of the through hole from the connection chamber; 6. The expansion valve according to claim 5.

7. a periphery of the opening of the through hole on an end surface of the valve seat member facing the third flow path portion is formed by a first seal member, a second seal member is formed around the opening of the through hole on the end surface of the valve seat member facing the drive portion; 7. The expansion valve according to claim 6.

8. the piston member has a base portion disposed within a stopper member of the power element and constituting the cylinder chamber together with the stopper member, and a piston member shaft portion; the valve body has a hole in which the piston member shaft is disposed, and a flow path portion communicating with the hole and through which the refrigerant flows, The piston member shaft is supported in the hole via a pair of O-rings, the pair of O-rings are arranged on both sides in the axial direction of the piston member shaft portion, sandwiching the opening of the flow path portion in the hole; a pressure equalizing space is formed by the inner surface of the hole, the pair of O-rings, and the piston member shaft portion; When the pair of O-rings are attached to the piston member and assembled to the valve body, the inner diameter of one O-ring is approximately the same as the outer diameter of the other O-ring, or the outer diameter of one O-ring is approximately the same as the outer diameter of the other O-ring.

8. The expansion valve according to claim 7.

9. The supply unit includes: an inflow passage provided in the valve body and connected to an external flow passage portion upstream of the valve chamber outside the valve body, for allowing the refrigerant upstream of the valve chamber to flow into the cylinder chamber; a valve device provided in the inflow passage or the external flow passage portion, which controls the inflow of the refrigerant into the cylinder chamber via the inflow passage; The expansion valve according to claim 1, further comprising:

10. The discharge section is an outflow path provided in the valve body and connected to an external flow path portion downstream of the valve chamber outside the valve body, for allowing the refrigerant in the cylinder chamber to flow downstream of the valve chamber via the external flow path portion; a valve device provided in the outflow path or the external flow path portion, which controls the outflow of the refrigerant in the cylinder chamber to a downstream side of the valve chamber via the outflow path; The expansion valve according to claim 2, further comprising:

11. the valve body has a low-pressure flow path through which a refrigerant having a pressure lower than that in the valve chamber flows, The power element is a housing fixed to the valve body; a diaphragm provided in the housing and dividing the interior of the housing into a pressure actuated chamber and a valve chamber side chamber communicating with the low-pressure flow path; a stopper member disposed in the valve-chamber side chamber and having the piston member disposed therein; Equipped with the cylinder chamber is formed by the stopper member and the piston member, a stopper portion provided on the stopper member and the piston member to prevent the piston member from moving beyond a predetermined position relative to the stopper member toward the valve chamber; The expansion valve according to claim 1, further comprising:

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