Expansion valve

Abstract

To provide an expansion valve capable of suppressing a pressure loss even though a valve-close state can be optionally ensured.SOLUTION: An expansion valve 1 includes a valve body 3, a valve chamber VS, a valve seat 20, a valve body 2, a first energizing device 4 energizing the valve body 3 toward the valve seat 20, an operation rod 5 driving the valve body, a power element 8 driving the operation rod 5, a dividing part that has at least a piston part 6 provided on the operation rod 5 and disposed in a communication hole and divides the inside of the communication hole into a cylinder chamber CS on the valve chamber VS side and a communication chamber disposed on a low-pressure channel side and communicating with the low-pressure channel, an inflow path that is formed on the valve body 1, allows the valve chamber VS and the cylinder chamber CS to communicate to each other to introduce a refrigerant in the valve chamber VS into the cylinder chamber CS or communicates with the cylinder chamber CS to make the refrigerant flow from the upstream side relative to the valve chamber VS into the cylinder chamber CS, and a first valve device EV that controls the inflow of the refrigerant into the cylinder chamber CS through the inflow path.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

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

[0003] Patent Document 1 discloses an expansion valve provided with a valve port in a communication path connecting a primary side passage into which high-pressure refrigerant flows and a valve chamber, and having a solenoid valve for opening or shielding the valve port.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the configuration of Patent Document 1, the operation of the expansion valve can be performed by opening the valve port with the solenoid valve, and the expansion valve can be forcibly closed by shielding the valve port.

[0006] Here, 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 has entered the primary side passage must pass through two places, the orifice of the solenoid valve and the orifice of the expansion valve, before flowing out to the outside of the expansion valve, which causes an increase in pressure loss. However, in order to reduce the pressure loss while maintaining the current structure of the expansion valve, the orifice diameter must be increased, which leads to an increase in the size of the expansion valve.

[0007] The present invention has been made in view of the above problems, and aims to provide an expansion valve that can suppress pressure loss while allowing the valve to be kept closed at will. [Means for solving the problem]

[0008] The solenoid valve of the present invention is Valve body and, A valve body comprising: a valve chamber in which the valve body is disposed inside; a valve hole formed downstream of the valve chamber; a valve seat formed around the valve hole; a low-pressure flow path within the valve chamber, spaced apart from the valve chamber in the direction toward the valve seat of the valve body, through which a refrigerant at a lower pressure than that in the valve chamber flows; and a communication hole formed between the valve chamber and the low-pressure flow path, communicating with the low-pressure flow path and the valve hole; A first biasing device that biases the valve body toward the valve seat, An operating rod, which is arranged in the valve hole and the communication hole and drives the valve body, A power element that drives the aforementioned operating rod, The operating rod has at least a piston portion provided on it and positioned within the communication hole, and the communication hole is divided into a cylinder chamber on the valve chamber side and a communication chamber positioned on the low-pressure flow path side and communicating with the low-pressure flow path, An inlet passage is formed in the valve body and connects the valve chamber and the cylinder chamber to introduce the refrigerant in the valve chamber into the cylinder chamber, or communicates with the cylinder chamber and allows the refrigerant to flow into the cylinder chamber from an upstream side of the valve chamber, The system includes a first valve device that controls the inflow of refrigerant into the cylinder chamber through the inflow passage, It is characterized by the following: [Effects of the Invention]

[0009] The present invention provides an expansion valve that can suppress pressure loss while allowing the valve to be kept closed at will. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 is a schematic cross-sectional view showing the open state of the expansion valve in the first embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view of the expansion valve in a section where the phase is shifted by 90 degrees around axis L compared to Figure 1. [Figure 3] This is a cross-sectional view showing an enlarged view of the area around the solenoid valve shown in Figure 2. [Figure 4] Figure 4 is a longitudinal cross-sectional view showing the closed state of the expansion valve in a similar cross-sectional view to that of Figure 2. [Figure 5] Figure 5 is a schematic cross-sectional view of an expansion valve in a modified example of the first embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view showing the open state of the expansion valve in the second embodiment. [Figure 7] Figure 7 is a longitudinal cross-sectional view showing the closed state of the expansion valve in the second embodiment. [Figure 8] Figure 8 is a schematic cross-sectional view of the expansion valve in a modified example of the second embodiment. [Figure 9] Figure 9 is a schematic cross-sectional view of an expansion valve according to another modified example of the second embodiment. [Figure 10] Figure 10 is a schematic cross-sectional view of an expansion valve according to yet another modification of the second embodiment. [Modes for carrying out the invention]

[0011] (First embodiment) The structure of the expansion valve 1 according to the first embodiment will be described below with reference to Figure 1. Figure 1 is a schematic cross-sectional view of the expansion valve 1 in the open state in this embodiment, and schematically shows the refrigeration cycle 100 to which it is connected. Figure 2 is a longitudinal cross-sectional view of the expansion valve 1 in a cross-section where the phase is shifted by 90 degrees around axis L compared to Figure 1, and is shown in the open state. Figure 3 is a cross-sectional view showing an enlarged view of the area around the solenoid valve EV shown in Figure 2. Figure 4 is a longitudinal cross-sectional view of the expansion valve 1 in a cross-section similar to that of Figure 2, and is shown in the closed state.

[0012] The expansion valve 1 includes a valve body 2 having a valve chamber VS, a valve element 3, a biasing device (first biasing device) 4, an operating rod 5, a piston member (also referred to as a piston portion) 6, and a power element 8. Let the axis of the expansion valve 1 be L. Here, along the axis L, the side of the power element 8 is taken as the upper side, and the side of the biasing device 4 is taken as the lower side.

[0013] In addition to the valve chamber VS, the valve body 2 includes a first flow path 21, a second flow path 22, and a return flow path 23. The first flow path 21 is a supply-side flow path, and refrigerant (also referred to as fluid) is supplied to the valve chamber VS through 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 outside the expansion valve through the operating rod insertion hole (valve hole) 27, the intermediate passage 22a, and the discharge-side flow path. The first flow path 21 and the valve chamber VS communicate with each other through a small-diameter passage 21a. Here, the enlarged-diameter portion 26, the central hole 28, the intermediate passage 22a, and the operating rod insertion hole 27 constitute the communication hole referred to in the claims. Also, in this communication hole, the portion on the low-pressure flow path side from the cylinder chamber CS described later is referred to as a communication chamber.

[0014] 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 in a non-communication state. 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 a communication state.

[0015] The operating rod 5 has a small-diameter portion 5a on the lower end side, a middle-diameter portion 5b having a larger diameter than the small-diameter portion 5a, and a large-diameter portion 5c having a larger diameter than the middle-diameter portion 5b. The small-diameter portion 5a of the operating rod 5 is inserted through the operating rod insertion hole 27 with a gap, and the lower end of the operating rod 5 is in contact with the upper surface of the valve element 3.

[0016] The operating rod 5 can press the valve element 3 in the valve-opening direction against the biasing force of the biasing device 4. When the operating rod 5 moves toward the valve element side, the valve element 3 is separated from the valve seat 20, and the expansion valve 1 is in an open state.

[0017] The operating rod 5 extends along the axis L from the valve body 3 to the power element 8 via an operating rod insertion hole 27, a central hole 28, an enlarged diameter section 26, a return passage 23, and a communication passage 2b, all coaxially formed in the valve body 2. The inner diameter of the enlarged diameter section 26 is larger than the inner diameter of the central hole 28, which slidably holds the medium diameter section 5b of the operating rod 5. A piston member 6 is positioned in the enlarged diameter section 26 so as to be displaceable relative to it in the direction of the axis L.

[0018] More specifically, the enlarged diameter portion 26 has a first cylindrical portion 26a adjacent to the central hole 28, a second cylindrical portion 26b having a larger diameter than the first cylindrical portion 26a, and a third cylindrical portion 26c adjacent to the return flow path 23 having a larger diameter than the second cylindrical portion 26b.

[0019] The piston member 6 consists of a small cylindrical portion 6a at the lower end, a larger cylindrical portion 6b with a larger diameter than the small cylindrical portion 6a, and a flange portion 6c with a larger diameter than the large cylindrical portion 6b, and has a through hole 6d of uniform diameter that penetrates vertically. The medium-diameter portion 5b of the operating rod 5 is inserted into the through hole 6d by press-fitting, and the upper end of the piston member 6 abuts against and is locked in place by the stepped portions of the large-diameter portion 5c and the medium-diameter portion 5b.

[0020] The flange portion 6c and the large cylindrical portion 6b of the piston member 6 are positioned within the third cylindrical portion 26c of the enlarged diameter portion 26, and a first O-ring OR1 is positioned between the large cylindrical portion 6b and the third cylindrical portion 26c to seal the space between them.

[0021] The small cylindrical portion 6a of the piston member 6 is positioned within the second cylindrical portion 26b of the enlarged diameter portion 26, leaving a space between them.

[0022] A second O-ring OR2 is positioned between the middle diameter portion 5b of the operating rod 5 and the first cylindrical portion 26a, sealing the space between them.

[0023] A cylinder chamber CS is formed between the enlarged diameter portion 26, sandwiched by the first O-ring OR1 and the second O-ring OR2, and the operating rod 5. The cylinder chamber CS is separated from the return passage (also called the low-pressure passage) 23 adjacent to the enlarged diameter portion 26 by the flange portion 6c of the piston member 6. A communication port 2d is formed extending downward from the lower end of the second cylindrical portion 26b of the enlarged diameter portion 26, inclined with respect to the axis L (see Figure 2). The cylinder chamber CS communicates only with the communication port 2d. The piston member 6, the first O-ring OR1, and the second O-ring OR2 constitute the partitioned portion.

[0024] Next, the power element 8 will be described. The power element 8 is attached to the opening 2a provided at the top of the valve body 2. The opening 2a communicates with the return flow path 23 through which the refrigerant from the evaporator passes via the communication passage 2b.

[0025] The power element 8 includes a plug 81, an upper cover member 82, a diaphragm 83, a stopper member 84, and a receiving member 86.

[0026] A hole 82a is formed at the top of the upper lid member 82, and it can be sealed with a plug 81.

[0027] The diaphragm 83 is made of a thin plate material with multiple concentric circular indentations formed on it.

[0028] The stopper member 84 has a disc portion and a cylindrical portion coaxially connected to the lower surface of the disc portion, and a fitting hole 84c is formed in the center of the lower end of the cylindrical portion.

[0029] 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, with a male thread 86c formed on the outer circumference of the hollow cylindrical portion.

[0030] During the assembly of the power element 8, the outer periphery of the upper cover member 82, the diaphragm 83, and the flange portion of the receiving member 86 are first overlapped, and these outer periphery portions are then integrated by circumferential welding, such as TIG welding, laser welding, or plasma welding.

[0031] Next, after sealing the working gas into the space enclosed by the upper cover member 82 and the diaphragm 83 (called the pressure working chamber PA) through the hole 82a formed in the upper cover member 82, the hole 82a is sealed with a plug 81, and the plug 81 is then fixed to the upper cover member 82 using projection welding or the like.

[0032] At this time, the working gas sealed in the pressure chamber PA causes the diaphragm 83 to be subjected to pressure in a way that causes it to protrude towards the receiving member 86, and so it is supported by contacting the upper surface of the stopper member 84 located in the lower space LS surrounded by the diaphragm 83 and the receiving member 86. Furthermore, since the disc portion 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.

[0033] When assembling the power element 8 to the valve body 2, the upper end of the operating rod 5, to which the piston member 6 is attached, is fitted into the fitting hole 84c of the stopper member 84, and the operating rod 5 is inserted into the valve body 2 from the lower end. Furthermore, the power element 8 is fixed to the valve body 2 by screwing the male thread 86c of the receiving member 86 into the female thread of the opening 2a of the valve body 2 and screwing it in. The space between the valve body 2 and the power element 8 is sealed by the packing PK. In this state, the lower space LS of the power element 8 is in communication with the return passage 23, i.e., the internal pressure is the same.

[0034] Next, the biasing device 4 will be described. In Figure 1, the biasing device 4 includes a coil spring 41 made by winding a circular wire spirally, a valve body support 42 attached to the upper end of the coil spring 41 to support the valve body 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 body support 42 and the coil spring 41. The spring receiving member 43 has the function of sealing the valve chamber VS of the valve body 2 and supporting the end of the coil spring 41 that biases the valve body 3 toward the valve seat 20.

[0035] A spherical valve body 3 is welded to the upper surface of the valve body support 42, and the two are integrated. The vibration-damping member 44 has, for example, radially protruding claw portions that elastically engage with the inner circumference of the valve chamber VS, and has the function of suppressing vibration of the valve body 3. A detailed description of the vibration-damping member 44 is omitted here, as it is described in detail in, for example, Japanese Patent Application Publication No. 2018-025331.

[0036] (Structure of a solenoid valve) Next, the structure of the solenoid valve (also called valve device) EV of this embodiment will be described with reference to Figures 2 and 3. Let the axis of the solenoid valve EV be O. Axis O is perpendicular to axis L.

[0037] In Figure 2, the valve body 2 has a large circular 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 and the valve chamber VS are connected by an inlet hole (first flow path section) 2h. A communication port (second flow path section) 2d is located on the inner circumference at an intermediate position of the medium opening 2f. Furthermore, the bottom of the small opening 2g and the intermediate passage 22a are connected by an outlet hole (third flow path section) 2j. Here, the intermediate passage 22a constitutes the downstream flow path downstream of the valve seat 20. The inlet hole 2h, the high-pressure chamber (also called a connection chamber) HS formed between the inlet hole 2h and the communication port 2d, the medium opening 2f, and the communication port 2d constitute the inflow passage, and the communication port 2d, the medium opening 2f, the small opening 2g, and the outlet hole 2j constitute the outflow passage.

[0038] In Figure 3, a cylindrical valve seat member 112 is positioned inside the central opening 2f, and is fixed to the central opening 2f by crimping a cylindrical crimped portion 2i formed at the bottom of the large opening (also called a recess) 2e radially inward.

[0039] The valve seat member 112 has a through-hole (also called a through hole) 112a extending along the axis O, a circumferential groove 112b formed around the entire circumference of the outer circumference at an intermediate position in the direction of the axis O, a radial hole 112c connecting the through-hole 112a and the circumferential groove 112b in the radial direction, and a recess 112d formed at the end on the side of the small opening 2g. The circumferential groove 112b communicates with the communication opening 2d. The circumferential groove 112b and the radial hole 112c constitute a relay path. Furthermore, a first communication path is formed by a part of the high-pressure chamber HS, the through-hole 112a of the valve seat member 112, the radial hole 112c, and the circumferential groove 112b, and a second communication path is formed by the through-hole 112a of the valve seat member 112, the radial hole 112c, the circumferential groove 112b, and the small opening 2g.

[0040] An annular first sealing member (also called the first sealing member) SL1 is attached to the recess 112d of the valve seat member 112 by adhesive or the like, and an annular second sealing member (also called the second sealing member) SL2 is attached to the end opposite to the recess 112d by adhesive or the like. The inner diameters of the first sealing member SL1 and the second sealing member SL2 are approximately equal to the inner diameter of the through-hole 112a. The first sealing member SL1 abuts against the stepped portion at the boundary between the central opening 2f and the small opening 2g, and the second sealing member SL2 abuts against the inner circumference of the central opening 2f, thereby sealing the space between the valve seat member 112 and the valve body 2.

[0041] The cylindrical valve stem member 113 has a long shaft portion (also simply called a shaft portion) 113a inserted so as to penetrate the through-hole 112a of the valve seat member 112 and the first seal member SL1 and the second seal member SL2, a flange portion 113b with a larger diameter than the through-hole 112a, and a short shaft portion 113c. There is a gap between the outer circumference of the long shaft portion 113a and the inner circumference of the through-hole 112a, the first seal member SL1 and the second seal member SL2 through which the refrigerant can pass, and the valve stem member 113 is relatively movable in the axial direction O relative to the valve seat member 112.

[0042] Around the short shaft portion 113c, a compression spring (second biasing device) 114 is positioned between the bottom of the small opening 2g and the opposing surface of the flange portion 113b, biasing the valve stem member 113 toward the large opening 2e relative to the bottom of the small opening 2g. The compression spring 114 and the solenoid valve EV constitute a second valve device, and the second valve device and the valve stem member 113 constitute a drive device.

[0043] The solenoid valve EV, which constitutes the first valve device and drive unit, comprises an annular base 120, a coil 132 for energizing and exciting, a yoke 133, a pipe 141 disposed on the inner circumference side of the yoke 133 and extending in the direction of axis O, a plunger (displacement member) 135 slidably disposed on the inner circumference side of the pipe 141 in the direction of axis O, a suction element 140 fixedly disposed on the inner circumference of the end of the pipe 141, and a housing 138 disposed to cover these.

[0044] The end of the pipe 141 is fixed to the inner circumference of the base 120 by press-fitting or brazing, and the base 120 is fixed to the valve body 2 by screwing the male thread 121 formed on the outer circumference of the base 120 into the female thread 2k formed on the inner circumference of the large opening 2e of the valve body 2. An O-ring OR3 is placed between the bottom of the large opening 2e and the base 120 to seal the space between the base 120 and the valve body 2. As a result, a high-pressure chamber HS is formed between the base 120 and the large opening 2e. The high-pressure chamber HS communicates with the inlet hole 2h and can also communicate with the through-hole (also called a through hole) 112a of the valve seat member 112.

[0045] A female threaded portion 142 is formed on the end face of the suction element 140 opposite to the pipe 141. The suction element 140 and the housing 138 are joined by screwing the mounting bolt 137 into the female threaded portion 142, with the housing 138 interposed between them. The housing 138 is fixed to the base 120 via a spacer 139.

[0046] The cylindrical plunger 135 is made of a magnetic material and consists of an enlarged diameter cylindrical portion 135a and a reduced diameter cylindrical portion 135b with a diameter larger than the inner diameter of the through-hole 112a. A circular recess 135c is formed at the end of the reduced diameter cylindrical portion 135b, and the end of the long axis 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 axis O). The plunger 135 is biased toward the valve seat member 112 by a compression coil spring 136 compressed between the plunger 135 and the suction element 140.

[0047] (Operation of the expansion valve) Referring to Figure 1, an example of operation when the expansion valve 1 is incorporated into the refrigeration cycle 100 will be described. The refrigerant pressurized by the compressor 101 in the refrigeration cycle 100 is liquefied in the condenser 102 and sent to the expansion valve 1. The refrigerant adiabatically expanded in the expansion valve 1 is then sent to the evaporator 103 of the refrigeration cycle 100, where it exchanges heat with the air flowing around the evaporator 103. The refrigerant returning from the evaporator 103 is returned to the compressor 101 side through the expansion valve 1 (more specifically, the return passage 23).

[0048] Here, as shown in Figure 4, the plunger 135 of the solenoid valve EV drives the valve shaft member 113 to the first position (described later), thereby enabling the expansion valve 1 to perform its intended operation. The expansion valve 1 is supplied with high-pressure refrigerant from the condenser 102. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to the first flow path 21.

[0049] When the valve body 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. On the other hand, when the valve body 3 is separated from the valve seat 20, the refrigerant supplied to the valve chamber VS is sent to the evaporator through the operating rod insertion hole 27 and the second flow path 22. The switching between the closed state (see Figure 4) and the open state (Figure 2) of the expansion valve 1 is performed by the operating rod 5 connected to the power element 8.

[0050] Inside the power element 8, there is a pressure-operated chamber PA and a lower space LS, separated by a diaphragm 83. Therefore, when the working gas in the pressure-operated chamber PA is liquefied, the actuator 5 moves towards the diaphragm, and when the liquefied working gas is vaporized, the actuator 5 moves towards the valve body. In this way, the expansion valve 1 is switched between the open and closed states.

[0051] Furthermore, the lower space LS of the power element 8 is in communication with the return passage 23. Therefore, the phase (gas phase, liquid phase, etc.) of the working gas in the pressure working chamber PA changes according to the temperature and pressure of the refrigerant flowing through the return passage 23, and the working rod 5 is driven. In other words, in the expansion valve 1 shown in Figure 1, the amount of refrigerant supplied from the expansion valve 1 to the evaporator is automatically adjusted according to the temperature and pressure of the refrigerant returning from the evaporator to the expansion valve 1.

[0052] (Forced closing action of the expansion valve) Next, the forced closing operation of the expansion valve 1 using the solenoid valve EV will be described. The valve stem member 113 is displaced along the axis O by the drive of the solenoid valve EV. The position where the flange portion 113b of the valve stem member 113 abuts against the valve seat member 112 is defined as the first position, and the position where the flange portion 113b of the valve stem member 113 is separated from the valve seat member 112 is defined as the second position. High-pressure refrigerant is supplied to the high-pressure chamber HS between the base portion 120 and the valve body 2 from the valve chamber VS through the inlet hole 2h.

[0053] When power is supplied to the coil 132 from an external power supply device, as shown in Figure 4, the plunger 135 is biased to move away from the valve seat member 112 against the biasing 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 flange portion 113b of the valve stem member 113 comes into contact with the first seal member SL1 due to the biasing force of the compression spring 114, so that the solenoid valve EV switches the valve stem member 113 to the first position for introducing high-pressure refrigerant into the cylinder chamber CS.

[0054] In this first position, the refrigerant pressure in the high-pressure chamber HS is transmitted from the through-hole 112a of the valve seat member 112 to the cylinder chamber CS via the radial hole 112c, circumferential groove 112b, and communication port 2d, thereby increasing the internal pressure of the cylinder chamber CS to high pressure. On the other hand, because the flange portion 113b of the valve stem member 113 is in contact with the first seal member SL1, leakage of refrigerant from the high-pressure chamber HS through the through-hole 112a to the small opening 2g side is suppressed, and the internal pressure of the cylinder chamber CS remains high.

[0055] The side of the piston member 6 opposite the cylinder chamber CS, with the flange portion 6c in between, faces the return passage 23 through which low-pressure refrigerant passes. When the cylinder chamber CS becomes high-pressure, the piston member 6 receives a force in the direction that expands the cylinder chamber CS due to the pressure difference with the refrigerant pressure in the return passage 23, causing the operating rod 5 connected to the piston member 6 to be displaced toward the power element 8. Therefore, even if the operating rod 5 receives a force from the power element 8 in the direction of opening the valve, the operating rod 5 rises against this force, and the valve body 3 can be placed in the closed position.

[0056] On the other hand, when the coil 132 is not powered from an external power supply device, as shown in Figure 2, the biasing force of the compression coil spring 136 causes the plunger 135 to move in a direction closer to the valve seat member 112. As a result, the end of the plunger 135 comes into contact with 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 solenoid valve EV switches the valve stem member 113 to a second position that shuts off the high-pressure refrigerant to the cylinder chamber CS.

[0057] Immediately after the flange portion 113b of the valve stem member 113 separates from the first seal member SL1, the internal pressure of the cylinder chamber CS is higher than the pressure of the refrigerant in the intermediate passage 22a. Therefore, at the second position, the pressure in the intermediate passage 22a is transmitted to the cylinder chamber CS via the outlet hole 2j, small opening 2g, through-hole 112a, radial hole 112c, circumferential groove 112b, and communication port 2d, and the refrigerant pressure in the cylinder chamber CS rapidly decreases to be approximately equal to the pressure in the intermediate passage 22a (and return passage 23). As a result, the axial force applied to the piston member 6 disappears, and the operating rod 5 becomes able to move up and down in accordance with the operation of the power element 8. Furthermore, since the end of the plunger 135 abuts against the second seal member SL2, leakage of refrigerant in the high-pressure chamber HS through the through-hole 112a into the intermediate passage 22a is suppressed, and the operation of the refrigeration cycle 100 is not affected.

[0058] According to this embodiment, by supplying power to the solenoid valve EV, the high-pressure refrigerant supplied from the capacitor 102 is introduced into the cylinder chamber CS, thereby forcibly raising the operating rod 5 via the piston member 6, and thereby enabling the forced closing function of the expansion valve 1 regardless of the operation of the power element 8.

[0059] Furthermore, by interrupting the power supply to the solenoid valve EV, the internal pressure of the cylinder chamber CS can be rapidly reduced by connecting the cylinder chamber CS with the intermediate passage 22a. As a result, the coercive force applied to the piston member 6 is eliminated, ensuring the expansion valve 1 operates as intended. At this time, the refrigerant from the condenser 102 is introduced directly into the valve chamber VS without passing through the solenoid valve EV, thus suppressing pressure loss and other issues.

[0060] Furthermore, the first O-ring OR1 and the second O-ring OR2, both made of rubber or resin, support the operating rod 5 via the piston member 6 with respect to the enlarged diameter portion 26 of the valve body 2. Therefore, even if vibration occurs in the operating rod 5, the damping function of the first O-ring OR1 and the second O-ring OR2 can suppress that vibration.

[0061] (modified version) Figure 5 is a longitudinal cross-sectional view of the expansion valve 1A according to a modified example, similar to Figure 2. In this embodiment, the expansion valve 1A differs from the first embodiment only in the shape of the valve body 2A and the arrangement of the annular plate (also called the locking portion) 7A. Since all other components are the same as in the first embodiment, the same reference numerals are used for common components and redundant explanations are omitted.

[0062] The valve body 2A has an inner circumferential step portion 2Am formed at the upper end of the enlarged diameter portion 26, and an annular plate 7A is attached to the inner circumferential step portion 2Am. The annular plate 7A, through which the operating rod 5 passes, is fixed to the valve body 2A so as to face the piston member 6 at a predetermined distance apart by crimping a crimped portion 2An formed adjacent to the inner circumferential step portion 2Am radially inward.

[0063] In the first embodiment, the axial force applied to the piston member 6 corresponds to the pressure difference between the internal pressure of the piston chamber CS and the internal pressure of the return passage 23. Therefore, if this pressure difference is excessive, the axial force applied to the piston member 6 will also be excessive, and there is a risk that the operating rod 5 will be pressed toward the power element 8 with great force. However, since the diaphragm 83 that receives this force is made of a thin plate material, if it is pressed toward the operating rod 5 with great force exceeding the allowable range, there is a risk that malfunctions such as deformation may occur.

[0064] In contrast, according to this modified version, when the piston member 6 is subjected to a force that causes it to rise beyond a predetermined distance, the upper end of the piston member 6 comes into contact with the lower surface of the annular plate 7A, thereby preventing the piston member 6 from rising any further. By the upper end of the piston member 6 coming into contact with the lower surface of the annular plate 7A, the upward movement of the operating rod 5 is suppressed, and deformation of the diaphragm 83 exceeding the allowable range can be suppressed.

[0065] (Second embodiment) Figure 6 is a schematic cross-sectional view showing the open state of the expansion valve 1B in the second embodiment, and schematically illustrates the refrigeration cycle 100B to which it is connected. Figure 7 is a longitudinal cross-sectional view showing the closed state of the expansion valve 1B in the second embodiment.

[0066] In this embodiment, the only difference from the first embodiment is that a solenoid valve is not provided. Since the other configurations are the same as in the first embodiment, the same reference numerals are used for common components and redundant explanations are omitted.

[0067] In the refrigeration cycle 100B of this embodiment, a branch pipe (pipe through which high-pressure refrigerant flows, also called an external flow path) DP is provided, branching off from the piping leading from the condenser 102 to the valve chamber VS of the expansion valve 1B and leading to the piping base 105B of the expansion valve 1B. An on-off valve (valve device) VL is attached to the branch pipe DP. The on-off valve VL constituting the first valve device in this embodiment can be selectively operated to an open position that opens the branch pipe DP and a closed position that closes it. The other configurations are the same as those of the refrigeration cycle in the first embodiment.

[0068] A communication port 2d connects the cylinder chamber CS of the valve body 2B to the outer circumference of the end of the large opening 2Be. A piping base 105B is attached to the large opening 2Be. The piping base 105B is fixed to the valve body 2B by screwing the male threads formed on the outer circumference of the piping base 105B into the female threads formed on the inner circumference of the large opening 2Be of the valve body 2B. A packing PK is placed between the large opening 2Be and the piping base 105B to seal the space between the piping base 105B and the valve body 2B. As a result, a high-pressure chamber HS is formed between the piping base 105B and the large opening 2Be.

[0069] The piping base 105B has a piping section 105Ba 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 piping base 105B and the piping section 105Ba, and also communicates with the cylinder chamber CS via a communication port 2d, but does not communicate with the valve chamber VS. The rest of the configuration is the same as that of the expansion valve in the first embodiment.

[0070] Next, the forced closing operation of the expansion valve 1B using the on-off valve VL will be described. In the on-off valve VL, the position in which the branch pipe DP is opened is defined as the first position, and the position in which the branch pipe DP is shielded is defined as the second position.

[0071] When the on-off valve VL is switched to the first position (the open position for introducing high-pressure refrigerant into the cylinder chamber CS), the high-pressure refrigerant in the branch pipe DP is supplied to the high-pressure chamber HS via the pipe section 105Ba, and the refrigerant pressure in the high-pressure chamber HS is transmitted to the cylinder chamber CS via the communication port 2d, making the internal pressure of the cylinder chamber CS high.

[0072] When the cylinder chamber CS becomes high pressure, the piston member 6 receives a force in the direction that expands the cylinder chamber CS due to the pressure difference with the refrigerant pressure in the return passage 23, causing the operating rod 5 connected to the piston member 6 to be displaced toward the power element 8. Therefore, even if the operating rod 5 receives a force from the power element 8 in the direction of opening the valve, the operating rod 5 rises against this force, and the valve body 3 can be placed in the closed position.

[0073] On the other hand, when the on-off valve VL is switched to the second position (the closed position which shuts off the high-pressure refrigerant to the cylinder chamber CS), 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 into the return flow path 23, for example, through the gap between the operating rod 5 and the piston member 6. As a result, the internal pressure of the cylinder chamber CS decreases, the axial force applied to the piston member 6 disappears, and the operating rod 5 becomes able to move up and down in accordance with the operation of the power element 8.

[0074] 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 forcibly raising the operating rod 5 via the piston member 6. This enables the forced closing function of the expansion valve 1 to be achieved regardless of the operation of the power element 8.

[0075] In contrast, by operating the on-off valve VL to the second position, the pressure in the cylinder chamber CS can be reduced, thereby eliminating the coercive force applied to the piston member 6 and ensuring the proper 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 on-off valve VL, thus suppressing pressure loss and other issues.

[0076] Furthermore, the on-off valve VL can be configured as a three-way switching valve, allowing for selective switching between a flow path connecting the branch pipe DP and the high-pressure chamber HS, and a flow path connecting the high-pressure chamber HS and the return flow path 23 (inlet of the compressor 101). In this case, connecting the branch pipe DP and the high-pressure chamber HS with the three-way switching valve can 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 with the three-way valve can rapidly decrease the internal pressure of the cylinder chamber CS. In this example, a three-way switching valve was used to describe switching between a flow path connecting the branch pipe DP and the high-pressure chamber HS and a flow path connecting the high-pressure chamber HS and the return flow path 23 (inlet of the compressor 101). However, 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 paths connecting the high-pressure chamber HS and the inlet side of the evaporator 103 include, for example, a flow path connecting the high-pressure chamber HS and the second flow path 22, and a flow path connecting the high-pressure chamber HS and the intermediate passage 22a.

[0077] (modified version) Figure 8 is a longitudinal cross-sectional view of the expansion valve 1C according to a modified example, similar to Figure 6. In this embodiment, the expansion valve 1C differs from the second embodiment only in the shape of the valve body 2C and the arrangement of the annular plate 7C. All other components are the same as in the second embodiment, so common components are denoted by the same reference numerals and redundant explanations are omitted.

[0078] The valve body 2C has an inner circumferential step portion 2Cm formed at the upper end of the enlarged diameter portion 26, and an annular plate 7C is attached to the inner circumferential step portion 2Cm. The annular plate 7C, through which the operating rod 5 passes, is fixed to the valve body 2C so as to face the piston member 6 at a predetermined distance apart by crimping a crimped portion 2Cn formed adjacent to the inner circumferential step portion 2Cm radially inward.

[0079] According to this modified version, when the piston member 6 is subjected to a force that causes it to rise beyond a predetermined distance, the upper end of the piston member 6 comes into contact with the lower surface of the annular plate 7C, thereby preventing the piston member 6 from rising any further. By the upper end of the piston member 6 coming into contact with the lower surface of the annular plate 7C, the upward movement of the operating rod 5 is suppressed, and deformation of the diaphragm 83 and the like can be suppressed.

[0080] It should be noted that the present invention is not limited to the embodiments described above, and any design changes that do not depart from the spirit of the invention are also included in the present invention.

[0081] As another variation, for example, a dedicated flow path and on-off valve may be used for exhausting pressure inside the cylinder chamber. A specific example of this will be explained with reference to Figures 9 and 10.

[0082] In the modified example shown in Figure 9, a discharge passage EX is formed in the valve body 2, connecting the cylinder chamber CS to the outside. 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 piping (also called an external flow path) HT. In this modified example, the discharge passage EX is included in the outflow passage. The other configurations are the same as those in the embodiment shown in Figure 6, so a redundant explanation is omitted.

[0083] In the modified example shown in Figure 9, high-pressure refrigerant is introduced into the cylinder chamber CS by opening the second on-off valve VL2 while keeping it closed. On the other hand, by opening the second on-off valve VL2 while keeping it closed, refrigerant flows from the cylinder chamber CS to the evaporator 103 via the discharge passage EX and piping HT.

[0084] In the modified example shown in Figure 10, a second on-off valve VL2 is installed in the middle of the pipe HT connecting the piping section 105Ba and the inlet side of the evaporator 103. The other configurations are the same as those in the embodiment shown in Figure 6, so a redundant explanation is omitted.

[0085] In the modified example shown in Figure 10, by closing the second on-off valve VL2 and opening the on-off valve VL, high-pressure refrigerant is introduced into the cylinder chamber CS via the high-pressure chamber HS. On the other hand, by closing the on-off valve VL and opening the second on-off valve VL2, refrigerant flows from the cylinder chamber CS to the evaporator 103 via the high-pressure chamber HS and the piping HT.

[0086] Furthermore, in the embodiments and modifications described above, the piston member is separate from the operating rod, but the piston and the operating rod may be formed integrally. Here, "integrated" means that the operating rod and the piston are formed from a single component.

[0087] This specification includes disclosures of the following inventions. (First form) Valve body and, A valve body comprising: a valve chamber in which the valve body is disposed inside; a valve hole formed downstream of the valve chamber; a valve seat formed around the valve hole; a low-pressure flow path within the valve chamber, spaced apart from the valve chamber in the direction toward the valve seat of the valve body, through which a refrigerant at a lower pressure than that in the valve chamber flows; and a communication hole formed between the valve chamber and the low-pressure flow path, communicating with the low-pressure flow path and the valve hole; A first biasing device that biases the valve body toward the valve seat, An operating rod, which is arranged in the valve hole and the communication hole and drives the valve body, A power element that drives the aforementioned operating rod, The operating rod has at least a piston portion provided on it and positioned within the communication hole, and the communication hole is divided into a cylinder chamber on the valve chamber side and a communication chamber positioned on the low-pressure flow path side and communicating with the low-pressure flow path, An inlet passage is formed in the valve body and connects the valve chamber and the cylinder chamber to introduce the refrigerant in the valve chamber into the cylinder chamber, or communicates with the cylinder chamber and allows the refrigerant to flow into the cylinder chamber from an upstream side of the valve chamber, The system includes a first valve device that controls the inflow of refrigerant into the cylinder chamber through the inflow passage, An expansion valve characterized by the following features.

[0088] (Second form) An outlet passage formed in the valve body and connected to the cylinder chamber, which allows the refrigerant in the cylinder chamber to flow downstream of the valve chamber, A second valve device for controlling the outflow of refrigerant from the cylinder chamber through the outflow passage, A first embodiment of an expansion valve characterized by comprising the following:

[0089] (Third form) The inflow passage has a first flow path section communicating with the valve chamber, a second flow path section communicating with the cylinder chamber, and a connecting chamber connected to the first flow path section and the second flow path section. The outflow passage has the second flow path section, the connection chamber, and a third flow path section that connects the downstream side of the valve chamber and the connection chamber. The connecting chamber has a first connecting channel that connects the first channel section and the second channel section, and a second connecting channel that connects the second channel section and the third channel section. The first valve device also serves as the second valve device, comprising a valve stem member disposed in the connection chamber and a drive device for driving the valve stem member. The valve stem member is formed to be movable between a first position in which the first and second flow paths are connected via the first communication passage of the connection chamber, and the second communication passage is closed, thereby disconnecting both the first and second flow paths from the third flow path, and a second position in which the second and third flow paths are connected via the second communication passage of the connection chamber, and the first communication passage is closed, thereby disconnecting both the second and third flow paths from the first flow path. The drive device moves the valve shaft member between the first position and the second position. A second form of expansion valve characterized by the following:

[0090] (Fourth form) The drive device is A drive unit provided on the valve body has a plunger, which moves the valve stem member from one of the first and second positions to the other. The system includes a second biasing device provided in the connection chamber for biasing the valve stem member from the other side toward the one side, A third form of expansion valve characterized by the following:

[0091] (Fifth form) The third flow path section opens in the connection chamber on the opposite side from the drive section, with the opening of the first flow path section in between. A valve seat member is positioned in the connection chamber between the opening of the first flow path and the opening of the third flow path to prevent the flow of refrigerant from the first flow path to the third flow path, covers the opening of the second flow path, and has a gap between it and the opening of the third flow path, comprising a through hole penetrating in the direction of movement of the plunger, and a relay path connecting the through hole and the opening of the second flow path, The valve stem member has a shaft portion that is disposed within the through hole and is movable in the axial direction of the through hole and has a flow path between it and the inner surface of the through hole, and a flange portion that is provided on the shaft portion and is disposed in the gap and can close the opening of the through hole by abutting against the valve seat member. The end face of the plunger is formed on a surface capable of closing the opening of the through hole. A fourth form of expansion valve characterized by the following:

[0092] (Sixth form) On the end face of the valve seat member on the drive unit side, the area around the opening of the through hole is formed by a second sealing member. On the end face of the valve member on the third flow path side, the area around the opening of the through hole is formed by the first sealing member. A fifth form of expansion valve characterized by the following:

[0093] (Seventh form) The compartment is provided with an O-ring between the piston and the inner surface of the communication hole, and the piston is supported by the valve body via the O-ring. An expansion valve according to any of the first to sixth embodiments, characterized by the above.

[0094] (Eighth form) A locking portion is provided in the cylinder chamber and contacts the piston portion when the piston portion moves a predetermined amount toward the power element side relative to the valve body, An expansion valve according to any of the first to seventh embodiments, characterized by the above.

[0095] (Ninth form) The inflow passage is connected to an external flow path provided outside the valve body, and the first valve device is provided in the external flow path. A first embodiment of an expansion valve characterized by the following:

[0096] (Tenth form) The outflow passage is connected to an external flow path provided outside the valve body, and the second valve device is provided in the external flow path. A second form of expansion valve characterized by the following: [Explanation of Symbols]

[0097] 1: Expansion valve 2: Valve body 3: Valve body 4: Biasing device 5: Actuator rod 6: Piston member 7: Ring plate 8: Power Element 20: Alveolar seat 21: First channel 22: Second channel 23: Return channel 26: Expanded diameter part 27: Actuator rod insertion hole 41: Coil spring 140: Attractor 135: Plunger 132: Coil EV: Solenoid valve VS: Valve chamber CS: Cylinder Room HS: High-pressure chamber

Claims

1. Valve body and, A valve body comprising: a valve chamber in which the valve body is disposed inside; a valve hole formed downstream of the valve chamber; a valve seat formed around the valve hole; a low-pressure flow path within the valve chamber, spaced apart from the valve chamber in the direction toward the valve seat of the valve body, through which a refrigerant at a lower pressure than that in the valve chamber flows; and a communication hole formed between the valve chamber and the low-pressure flow path, communicating with the low-pressure flow path and the valve hole; A first biasing device that biases the valve body toward the valve seat, An operating rod, which is arranged in the valve hole and the communication hole and drives the valve body, A power element that drives the aforementioned operating rod, The operating rod has at least a piston portion provided on it and positioned within the communication hole, and the communication hole is divided into a cylinder chamber on the valve chamber side and a communication chamber positioned on the low-pressure flow path side and communicating with the low-pressure flow path, An inlet passage is formed in the valve body and connects the valve chamber and the cylinder chamber to introduce the refrigerant in the valve chamber into the cylinder chamber, or communicates with the cylinder chamber and allows the refrigerant to flow into the cylinder chamber from an upstream side of the valve chamber, A first valve device for controlling the inflow of refrigerant into the cylinder chamber through the inflow passage, An expansion valve characterized by the following features.

2. An outlet passage formed in the valve body and connected to the cylinder chamber, which allows the refrigerant in the cylinder chamber to flow downstream of the valve chamber, The system includes a second valve device for controlling the outflow of refrigerant from the cylinder chamber through the outflow passage, The expansion valve according to feature 1.

3. The inflow passage has a first flow path section communicating with the valve chamber, a second flow path section communicating with the cylinder chamber, and a connecting chamber connected to the first flow path section and the second flow path section. The outflow passage has the second flow path section, the connection chamber, and a third flow path section that connects the downstream side of the valve chamber and the connection chamber. The connection chamber has a first connecting channel that connects the first channel section and the second channel section, and a second connecting channel that connects the second channel section and the third channel section. The first valve device also serves as the second valve device, comprising a valve stem member disposed in the connection chamber and a drive device for driving the valve stem member. The valve stem member is formed to be movable between a first position in which the first and second flow paths are connected via the first communication passage of the connection chamber, and the second communication passage is closed, thereby disconnecting both the first and second flow paths from the third flow path, and a second position in which the second and third flow paths are connected via the second communication passage of the connection chamber, and the first communication passage is closed, thereby disconnecting both the second and third flow paths from the first flow path. The expansion valve according to claim 2, characterized in that the drive device moves the valve shaft member between the first position and the second position.

4. The drive device is A drive unit provided on the valve body has a plunger, which moves the valve stem member from one of the first and second positions to the other. The system includes a second biasing device provided in the connection chamber for biasing the valve stem member from the other side toward the one side, The expansion valve according to claim 3.

5. The third flow path section opens in the connection chamber on the side opposite to the drive section, with the opening of the first flow path section in between. A valve seat member is positioned in the connection chamber between the opening of the first flow path and the opening of the third flow path to prevent the flow of refrigerant from the first flow path to the third flow path, covers the opening of the second flow path, and has a gap between it and the opening of the third flow path, comprising a through hole that penetrates in the direction of movement of the plunger, and a relay path that relays between the through hole and the opening of the second flow path, The valve stem member has a shaft portion that is disposed within the through hole and is movable in the axial direction of the through hole and has a flow path between it and the inner surface of the through hole, and a flange portion that is provided on the shaft portion and is disposed in the gap and can close the opening of the through hole by abutting against the valve seat member. The end face of the plunger is formed on a surface capable of closing the opening of the through hole. The expansion valve according to feature 4.

6. On the end face of the valve seat member on the drive unit side, the area around the opening of the through hole is formed by a second sealing member. On the end face of the valve seat member on the third flow path side, the area around the opening of the through hole is formed by the first sealing member. The expansion valve according to claim 5, characterized in that it is a feature of the present invention.

7. The compartment is provided with an O-ring between the piston and the inner surface of the communication hole, and the piston is supported by the valve body via the O-ring. The expansion valve according to feature 1.

8. A locking portion is provided in the cylinder chamber and contacts the piston portion when the piston portion moves a predetermined amount toward the power element side relative to the valve body, An expansion valve according to any one of claims 1 to 7, characterized by the features described above.

9. The inflow passage is connected to an external flow path provided outside the valve body, and the first valve device is provided in the external flow path. The expansion valve according to feature 1.

10. The outflow passage is connected to an external flow path provided outside the valve body, and the second valve device is provided in the external flow path. The expansion valve according to feature 2.

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