Electrically operated valve and refrigeration cycle system

Abstract

The present invention aims at an electric valve capable of achieving improvement in workability and durability by suppressing damage of a metal member by a reinforcing fiber and suppressing generation of wear debris. The electric valve (10) is provided with a valve main body (1A), a drive unit (3) that rotates a drive screw shaft (33), a screw feed mechanism (4) that advances and retreats the screw shaft in the axial direction (L) in conjunction with rotation of the screw shaft, a valve core (2) that approaches and retreats relative to a valve seat portion (1G) in conjunction with advancement and retreat of the screw shaft, and a connecting body (5) that connects the screw shaft and the valve core. The screw feed mechanism has an internal thread member (42) supported by the valve main body (1A), an external thread portion (33B) of the screw shaft (33) is threadedly coupled to an internal thread portion (42A) of the internal thread member (42), and the internal thread member (42) is made of a resin containing a reinforcing fiber (F). The screw shaft is made of a metal member having the highest hardness, as compared with a metal-made sliding member that slides relative to other members.

Description

Technical Field

[0001] This invention relates to electric valves and refrigeration circulation systems. Background Technology

[0002] Currently, as an electric valve, there is a known type that includes a valve body, a stepper motor, a lead screw, and a valve holder. The lead screw is threadedly engaged with an internally threaded component supported by the valve body. The stepper motor rotates the lead screw, thereby driving the lead screw and valve core to move forward and backward (see, for example, Patent Documents 1 and 2). In the electric valve described in Patent Document 1, a metal lead screw (rotor shaft) is threadedly engaged with a resin internally threaded component, and the threaded portions slide against each other as the lead screw rotates. Furthermore, in the electric valves of Patent Documents 1 and 2, a resin spring seat component is built into the metal valve holder (cylindrical component), and the inner circumferential surface of the valve holder slides relative to the outer circumferential surface of the spring seat component.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-148643

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-108535 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in existing electric valves, metal parts (lead screw, valve holder) slide relative to resin parts (internal thread parts, spring seat parts). But as resin parts, to improve workability and durability, resin materials filled with reinforcing fibers are sometimes used. If such resin parts containing reinforcing fibers slide relative to metal parts, wear debris may be generated due to damage to the metal parts caused by the reinforcing fibers, potentially leading to a decrease in workability and durability.

[0009] The purpose of this invention is to provide an electric valve that improves workability and durability by suppressing damage to metal parts by reinforcing fibers and suppressing the generation of wear debris.

[0010] Solution for solving the problem

[0011] To solve the aforementioned problems and achieve the objective, the invention described in Solution 1 is an electric valve comprising a valve body constituting a valve chamber and a valve seat, a drive unit that drives a lead screw shaft to rotate, a threaded feed mechanism that causes the lead screw shaft to move forward and backward along the axial direction as the lead screw shaft rotates, a valve core that can approach or move away from the valve seat as the lead screw shaft moves forward and backward, and a connecting body that connects the lead screw shaft and the valve core. The threaded feed mechanism is characterized by having an internal threaded component supported on the valve body, the external threaded portion of the lead screw shaft being threadedly engaged with the internal threaded portion of the internal threaded component, the internal threaded component being made of resin containing reinforcing fibers, and the lead screw shaft being made of a metal component with the highest hardness compared to a metal sliding component that slides relative to other components.

[0012] According to this invention, the lead screw shaft has an external thread portion that is threadedly engaged with an internal thread portion of an internal thread component made of resin containing reinforcing fibers. Compared to a metal sliding member that slides relative to other components, this lead screw shaft is made of a metal component with the highest hardness. Here, when the internal thread portion slides with the external thread portion, the resin in the internal thread portion first wears away, exposing the reinforcing fibers. Then, the external thread portion is cut by the exposed reinforcing fibers, generating wear debris. Moreover, since the sliding surface of the thread teeth of the internal thread component contains reinforcing fibers with an orientation direction intersecting the sliding surface, the exposed reinforcing fibers are easily hooked by the sliding external thread portion due to this orientation. Therefore, wear debris is more easily generated, especially in the external thread portion, compared to a metal sliding member that slides relative to other components. In addition, the portions where the external and internal thread portions are located are mostly in the electric valve where there is no refrigerant flow. These portions are not flushed by refrigerant and are more susceptible to the generation of wear debris compared to the portions where a metal sliding member that slides relative to other components is located. Therefore, the operability and durability of the electric valve are easily deteriorated. However, according to the structure of the present invention, compared with the sliding metal part that slides relative to other parts, the lead screw shaft is made of a metal part with the highest hardness. Therefore, even when the external thread part slides relative to the internal thread part, it is possible to suppress the damage of the reinforcing fiber to the metal part and suppress the generation of wear debris, thereby improving workability and durability.

[0013] Preferably, the other components are resin components containing reinforcing fibers, the electric valve includes a metal sliding member that slides relative to the resin component, and the hardness of the lead screw is higher than the hardness of the metal sliding member that slides relative to the resin component. Furthermore, preferably, the connecting body includes the resin component and a metal sliding member that slides relative to the resin component, and the hardness of the lead screw is higher than the hardness of the metal sliding member that slides relative to the resin component. Furthermore, preferably, the connecting body includes a ball bearing, and the hardness of the lead screw is higher than the hardness of any other metal sliding member that slides relative to the resin component. Furthermore, preferably, the connecting body includes a compression spring that applies force to the valve core relative to the lead screw in the axial direction, and the hardness of the lead screw is higher than the hardness of any other metal sliding member that slides relative to the resin component. Furthermore, preferably, the other components are resin components containing reinforcing fibers, and the electric valve includes a metal sliding member that slides relative to the resin component along the axial direction, wherein the hardness of the lead screw is higher than the hardness of the metal sliding member that slides relative to the resin component along the axial direction. Furthermore, preferably, the connecting body includes the resin component and a metal sliding member that slides relative to the resin component along the axial direction, wherein the hardness of the lead screw is higher than the hardness of the metal sliding member that slides relative to the resin component along the axial direction. Furthermore, the orientation direction of the reinforcing fibers in the sliding surface of the internal thread component includes at least a direction intersecting the sliding surface. Furthermore, preferably, the connecting body includes a compression spring that applies force to the valve core relative to the lead screw in the axial direction, a spring seat component that transmits the force of the compression spring, and a metal cylindrical component that slides relative to the spring seat component, wherein the hardness of the lead screw is higher than the hardness of the metal cylindrical component that slides relative to the spring seat component. Furthermore, preferably, the spring seat component is made of resin containing reinforcing fibers, and the orientation direction of the reinforcing fibers in the sliding surface of the spring seat component is consistent with the direction along the sliding surface.

[0014] According to this structure, the electric valve of the present invention includes a spring seat component, which is a resin component containing reinforcing fibers, and a cylindrical component, which is a metal sliding component, sliding relative to the spring seat component. Here, as described above, the orientation direction of the reinforcing fibers in the sliding surface of the internal thread component includes at least a direction intersecting the sliding surface, while the orientation direction of the reinforcing fibers in the sliding surface of the spring seat component is consistent with the direction along the sliding surface. According to this orientation, as described above, even if the reinforcing fibers are exposed, they are unlikely to be hooked by the cylindrical component sliding relative to the spring seat component, and wear debris is unlikely to be generated. Moreover, the hardness of the lead screw shaft becomes higher than the hardness of other metal sliding components such as the cylindrical component, except for ball bearings and compression springs. That is, compared to the hardness of a metal sliding part (cylindrical part) that slides with a resin part (spring seat part) having reinforcing fibers that, even if their orientation is aligned with the direction along the sliding surface and are exposed as described above, have a relatively small impact on sliding, the hardness of a metal sliding part (lead screw shaft) that slides with a resin part (internal thread part) having reinforcing fibers that, if exposed as described above, have a large impact on sliding, is higher. Therefore, damage to the metal part by the reinforcing fibers can be suppressed, and the generation of wear debris can be suppressed.

[0015] Furthermore, preferably, the spring seat component slides relative to the inner or outer circumferential surface of the cylindrical component along the axial direction. Additionally, preferably, the threaded feed mechanism includes a metal fixing member that supports the internal threaded component against the valve body. This fixing member has a cylindrical portion incorporating the internal threaded component and a protruding edge fixed to the valve body. With this structure, an internal threaded component containing reinforcing fibers can be incorporated into the fixing member and fixed to the valve body using the protruding edge of the fixing member, thus enabling the formation of a high-strength internal threaded component at low cost.

[0016] Furthermore, the refrigeration cycle system of the present invention includes a compressor, an expansion valve, and an evaporator, characterized in that an electric valve as described in any of the above-mentioned embodiments is used as the expansion valve. According to this structure, the refrigeration cycle system can be configured using an electric valve that suppresses damage to metal components by reinforcing fibers and suppresses the generation of wear debris.

[0017] The effects of the invention are as follows.

[0018] According to the present invention, an electric valve can be provided that improves workability and durability by suppressing damage to metal parts by reinforcing fibers and suppressing the generation of wear debris. Attached Figure Description

[0019] Figure 1This is a longitudinal sectional view showing the open state of an electric valve according to one embodiment of the present invention.

[0020] Figure 2 This is a longitudinal sectional view showing the closed state of the aforementioned electric valve.

[0021] Figure 3 yes Figure 2 A magnified view of a portion of region P1.

[0022] Figure 4 yes Figure 2 A magnified view of a portion of region P2.

[0023] Figure 5 This is a diagram illustrating the refrigeration cycle system of the present invention.

[0024] In the picture:

[0025] 1A—Valve body, 1G—Valve seat, 2—Valve core, 3—Drive unit, 33—Lead screw shaft, 33B—External thread, 4—Threaded feed mechanism, 42—Internal thread component, 42A—Internal thread component, 5—Connector, 51—Cylindrical component (metal sliding component), 52—Spring seat component (resin component), 10—Electric valve, F—Reinforcing fiber, L—Axis. Detailed Implementation

[0026] The following is based on Figures 1-5 One embodiment of the present invention will be described. For example... Figure 1 As shown, the electric valve 10 of this embodiment includes a valve housing 1, a valve core 2, a drive unit 3, a threaded feed mechanism 4, and a connecting body 5 with a compression spring 53. Furthermore, the concept of "up and down" in the following description is different from... Figure 1 The figures above and below correspond to each other. The valve housing 1 is configured to include: a bottomed cylindrical valve body 1A; a cylindrical connecting member 1B connected to the upper end of the valve body 1A; and a housing 1C connected to the upper end of the connecting member 1B. The valve body 1A is a component made of machined metal such as SUS (stainless steel) or brass, and its interior forms a cylindrical valve chamber 1D. A first port 1E communicating with the inside and outside of the valve chamber 1D is formed on the side wall of the valve body 1A, and a second port 1F communicating with the inside and outside of the valve chamber 1D is formed on the bottom wall of the valve body 1A. A first connector pipe 11 communicating with the valve chamber 1D and allowing refrigerant to flow in or out is installed at the first port 1E, and a second connector pipe 12 communicating with the valve chamber 1D and allowing refrigerant to flow in or out is installed at the second port 1F.

[0027] The peripheral portion of the second port 1F on the side near the valve chamber 1D forms a valve seat portion 1G for the valve core 2 to approach or move away from. The connecting member 1B is formed into a cylindrical component by stamping from a metal sheet made of SUS and cutting from a cylindrical component, and is riveted or brazed to the upper end of the valve body 1A. The outer shell 1C is formed into a cup shape that protrudes upward along the axis L. The lower end of the outer shell 1C is arranged in an annular shape to surround the upper end of the connecting member 1B in the circumferential direction, and is welded to the upper end of the connecting member 1B. A guide member 13 is provided at the boundary between the valve body 1A and the connecting member 1B inside the valve housing 1, which guides the needle-like portion 21 of the valve core 2 along the axis L. A guide hole 13a centered on the axis L is formed in the center of the guide member 13.

[0028] The valve core 2 is designed to move closer to or further away from the valve seat 1G as the lead screw 33 moves forward and backward. The valve core 2 includes a cylindrical needle-shaped portion 21 extending along the axis L and a flange portion 22 at the upper end of the needle-shaped portion 21. The lower end of the needle-shaped portion 21 has a tapered front end portion 21A. The upper end of the needle-shaped portion 21 has a reduced diameter portion 21B with a diameter smaller than that of the lower end. The needle-shaped portion 21 is inserted into the guide hole 13a of the guide member 13 with a small clearance and is guided forward and backward in the axis L direction. The flange portion 22 is an anti-detachment component that prevents the needle-shaped portion 21 from detaching from the connector 5 when the connector 5 is connected to the valve core 2, and is formed with a diameter larger than that of the reduced diameter portion 21B.

[0029] The drive unit 3 includes a stepper motor 3A as an electric motor and a limiting mechanism 3B for limiting the rotation of the stepper motor 3A. The stepper motor 3A includes: a stator coil 31 disposed on the outer periphery of the housing 1C; a magnetic rotor 32 disposed on the inner periphery of the stator coil 31 across the housing 1C and rotating circumferentially along the axis L; and a lead screw 33, which is driven to rotate integrally with the magnetic rotor 32 and serves as a drive shaft. An extension shaft 32A protruding upward is provided at the upper end of the magnetic rotor 32. The upper end of the lead screw 33 is fixed to the center of the magnetic rotor 32 via a fixing member 33A. The lead screw 33 is made of stainless steel with a hardness higher than that of SUS303 and SUS304. Specifically, SUS303 and SUS304 have a hardness of approximately 200 (Hv conversion) or less (Hv approximately 200 means 150-240 Hv) in Vickers hardness, but the lead screw 33 of this embodiment is made of a metal part with a hardness of approximately 300 (Hv approximately 300 means 250-340 Hv) or more. Generally, the hardness of SUS304 is approximately 200 or less, therefore, the lead screw 33 of this embodiment has a hardness of approximately 30% or more higher than that of a drive shaft made of SUS304. An external thread portion 33B is formed at the center of the lead screw 33 in the axial direction L, and this external thread portion 33B constitutes part of the threaded feed mechanism 4. The lower end of the lead screw 33 is formed with a diameter larger than the diameter of other parts of the lead screw 33, constituting an expanded diameter portion 33C. Furthermore, a retaining member 34 that covers the outer periphery of the lead screw shaft 33 in the circumferential direction is installed between the external thread portion 33B and the expanded diameter portion 33C in the lead screw shaft 33.

[0030] The limiting mechanism 3B includes: a guide member 35 hanging from the top of the housing 1C; a guide line 36 spirally wound around the outer periphery of the guide member 35; and a movable slider 37 guided by the guide line 36 and movable in the vertical direction. The guide member 35 is configured such that its central axis is coaxial with the central axis of the lead screw 33 and extends along the axis L. The movable slider 37 is configured to be embedded in the groove of the spiral of the guide line 36 and wound around it. The movable slider 37 has a claw portion 37A protruding radially outward from the guide member 35. The claw portion 37A abuts against the aforementioned extension shaft 32A provided on the magnetic rotor 32 in the circumferential direction along the axis L. With this structure, as the magnetic rotor 32 rotates, the movable slider 37 is driven to rotate along the groove of the guide line 36 in the circumferential direction of the guide member 35, thereby allowing the movable slider 37 to move in the vertical direction.

[0031] An upper limiter 36A and a lower limiter 36B are formed at the upper and lower ends of the guide wire body 36, respectively, to abut against the claw portion 37A of the movable slider. The upper limiter 36A and the lower limiter 36B are configured to restrict the rotation of the claw portion 37A that abuts against it. According to this structure, the movable slider 37A, which abuts against the upper limiter 36A, cannot rotate further. Furthermore, if the rotation of the movable slider 37A is restricted, the rotation of the magnetic rotor 32 that drives the movable slider 37 is also restricted. That is, the upper limiter 36A functions as a limiter defining the uppermost position of the magnetic rotor 32. Similarly, if the claw portion 37A abuts against the lower limiter 36B, the rotation of the movable slider 37 is restricted, and the rotation of the magnetic rotor 32 is also restricted. That is, the lower limiter 36B functions as a limiter defining the lowermost position of the magnetic rotor 32.

[0032] The threaded feed mechanism 4, driven by the stepper motor 3A, rotates the lead screw shaft 33, causing the lead screw shaft 33 to move forward and backward along the axis L. This threaded feed mechanism 4 includes: a metal fixing member 41 fixed to the upper end of the connecting member 1B in the valve housing 1; an internally threaded member 42 supported by the valve body 1A via the fixing member 41; and the aforementioned externally threaded portion 33B threadedly engaged with the internally threaded portion 42A of the internally threaded member 42. The fixing member 41, which supports the internally threaded member 42 on the valve body 1A, has a cylindrical portion 41A extending along the axis L and a protruding edge portion 41B protruding radially outward from the lower end of the cylindrical portion 41A. The cylindrical portion 41A is configured to house the internally threaded member 42. The protruding edge portion 41B is fixed to the valve body 1A via the connecting member 1B by riveting or welding to the upper end of the connecting member 1B. The internally threaded member 42 is formed and fixed to the inner circumference of the cylindrical portion 41A by inlay forming. The internal thread component 42 is made of resin with PPS (polyphenylene sulfide) as the main component and filled with reinforcing fibers such as CF (carbon fiber), GF (glass fiber), and fluororesin such as PTFE (polytetrafluoroethylene). An internal thread portion 42A is formed in the center of the internal thread component 42, with the central axis coaxial with the central axis of the lead screw shaft 33.

[0033] The internal thread portion 42A is formed simultaneously with the aforementioned insert forming, or it is formed by machining after insert forming. Furthermore, regardless of the method used, it is as follows: Figure 3As shown, the orientation direction of the reinforcing fiber F is randomly oriented in various directions. Here, the upper and lower surfaces of the thread teeth of the internal thread portion 42A become sliding surfaces for the external thread portion 33B to slide relative to the thread feed of the internal thread portion 42A. However, since the orientation direction of the reinforcing fiber F is random as described above, the internal thread component 42 contains a large number of reinforcing fibers F with orientation directions intersecting the sliding surface. That is, the orientation direction of the reinforcing fiber F in the sliding surface of the internal thread component 42 includes at least the direction intersecting the sliding surface. This is because: in the case of insert molding, resin flows into the unevenness of the internal thread portion 42A in a complex manner. And because: in the case of machining, in the stage before forming the internal thread portion 42A, there is no structure to guide the reinforcing fiber F to be oriented in the direction along the sliding surface. As described above, the external thread portion 33B is made of SUS with high hardness, threadedly engaged with the internal thread portion 42A, and threadedly fed while sliding along the upper and lower surfaces of the thread teeth in the circumferential direction. That is, if the magnetic rotor 32 rotates, the lead screw shaft 33 rotates, and the external threaded part 33B performs threaded feed, thereby the lead screw shaft 33 moves forward and backward within the valve body 1.

[0034] The connecting body 5 is a component that connects the lead screw shaft 33 and the valve core 2. It includes a metal cylindrical component 51 (metal sliding component) disposed on the side of the lead screw shaft 33, a resin spring seat component 52 (resin component) disposed on the side of the valve core 2, and a metal compression spring 53 sandwiched between the cylindrical component 51 and the spring seat component 52. The cylindrical component 51 is a metal sliding component that is inserted into the cylindrical guide portion 52A of the spring seat component 52 and slides relative to the spring seat component 52 along the axis L. The cylindrical component 51 is made of stainless steel such as SUS303 or SUS304, which has a lower hardness than the lead screw shaft. It is configured to have a cylindrical sliding portion 51A extending along the axis L and a lead screw shaft side flange portion 51B protruding radially outward from the upper end of the cylindrical sliding portion 51A. The cylindrical sliding portion 51A is disposed with the lead screw shaft 33 at a predetermined gap in the radial direction. The lead screw shaft flange 51B is configured to abut the upper end of the compression spring 53.

[0035] A stepped portion 51A1 protruding radially inward is formed at the center of the inner peripheral wall of the cylindrical sliding portion 51A in the direction of the axis L. A rolling bearing 54 (ball bearing) is provided in this stepped portion 51A1. The rolling bearing 54 is a bearing that connects the lead screw shaft 33 and the cylindrical component 51 to be able to rotate relative to each other, and is configured to have an inner ring 54A, a steel ball 54B, and an outer ring 54C. The inner ring 54A is arranged to partially cover the outer periphery of the lead screw shaft 33 from the lower end of the aforementioned retaining member 34 to the foreground of the expanded diameter portion 33C. When the outer ring 54C is placed on the stepped portion 51A1, it is fixed to the cylindrical sliding portion 51A by a retaining ring 55 pressed into the inner peripheral surface of the cylindrical sliding portion 51A in the direction of the axis L. Thus, the lead screw shaft 33 and the cylindrical component 51 are connected via the rolling bearing 54. A connecting hole 51A2 is formed through the center of the bottom wall of the cylindrical sliding part 51A, coaxial with the axis L of the lead screw shaft 33. This connecting hole 51A2 is for insertion into the connecting cylindrical part 56 described below.

[0036] The spring seat component 52 is a component that transmits the force of the compression spring 53 along the axis L. It includes a cylindrical guide portion 52A extending along the axis L and a valve core-side flange portion 52B protruding circumferentially outward from the lower end of the cylindrical guide portion 52A. The cylindrical guide portion 52A has an inner diameter larger than the diameter of the cylindrical sliding portion 51A, and is designed to allow the cylindrical sliding portion 51A to be inserted. With this structure, the inner circumferential surface of the spring seat component 52 forms a sliding surface, and slides relative to the outer circumferential surface of the cylindrical sliding portion 51A along the axis L. The valve core-side flange portion 52B is configured to abut against the lower end of the compression spring 53. The cylindrical guide portion 52A and the valve core-side flange portion 52B are made of resin with PPS (polyphenylene sulfide) as the main component, and filled with reinforcing fibers such as CF (carbon fiber) and GF (glass fiber), and fluororesin such as PTFE (polytetrafluoroethylene).

[0037] The cylindrical guide portion 52A and the valve core side flange portion 52B are formed by injection molding or by machining resin material. Figure 4 As shown, when formed using any method, the orientation direction of the reinforcing fibers F in the cylindrical guide portion 52A increases along the direction of the sliding surface of the spring seat member 52 (axis L direction). That is, the orientation direction of the reinforcing fibers in the sliding surface of the spring seat member 52 is consistent with the direction along the sliding surface. This is because: in the case of injection molding, the gate is located above or below the axis L. And because: in the case of machining, resin material that aligns the orientation of the reinforcing fibers F in the axis L direction is prepared in advance before machining.

[0038] A through hole 52A1, coaxial with the axis L of the lead screw shaft 33, is formed in the center of the bottom wall of the cylindrical guide portion 52A. A connecting cylindrical portion 56 is inserted into the through hole 52A1. The connecting cylindrical portion 56 connects the cylindrical component 51 to the spring seat component 52 and the spring seat component 52 to the valve core 2, and extends along the axis L throughout the inner and outer sides of the cylindrical guide portion 52A. A radially inward recessed groove 56A is formed on the outer side of the cylindrical guide portion 52A at the lower end of the side wall of the connecting cylindrical portion 56. A C-shaped retaining ring 57 is radially inserted into the groove 56A. The retaining ring 57 is configured to be inserted into a recess 52A2 facing the drive portion 5. The recess 52A2 is formed on the lower end face of the bottom wall of the cylindrical guide portion 52A and opens on the inlet port A side. Furthermore, the connecting cylinder 56 is connected to the spring seat member 52 by the rebound force of the compression spring 53, which is pressed against the drive part 5 via the spring seat member 52 when the retaining ring 57 is inserted into the recess 52A2. An upper flange 56B is formed at the upper end of the connecting cylinder 56, which is hooked by the edge of the connecting hole 51A2, thereby connecting the spring seat member 52 to the cylindrical member 51. In addition, although not shown, a portion of the side wall of the connecting cylinder 56 is cut from the upper end to the lower end, and this cut is used to form an opening communicating with the inside of the connecting cylinder 56.

[0039] The inner diameter of the connecting cylinder portion 56 is set to be larger than the diameter of the reduced-diameter portion 21B in the needle-shaped portion 21, and smaller than the diameter of the flange portion 22. Furthermore, the dimension of the connecting cylinder portion 56 in the L-axis direction is approximately the same as the dimension of the reduced-diameter portion 21B in the L-axis direction. Also, the dimension of the width of the opening on the side wall of the cylindrical connecting portion 56 intersecting the L-axis direction is approximately the same as the diameter of the reduced-diameter portion 21B. Moreover, the reduced-diameter portion 21B is inserted radially into the connecting cylinder portion 56 through the opening. With this structure, the reduced-diameter portion 21B is inserted into the connecting cylinder portion 56 with a radial gap, and the flange portion 22 acts as an anti-dislodgement component, preventing the valve core 2 from falling downwards into the connecting cylinder portion 56, thus connecting the valve core 2 to the spring seat component 52.

[0040] The compression spring 53 applies force to the valve core 2 relative to the lead screw shaft 33 in the axial direction L. The compression spring 53 is made of metal and is clamped between the cylindrical component 51 and the spring seat component 52 throughout the axial direction L. The upper end of the compression spring 53 abuts against the lead screw shaft side flange 51B, and the lower end of the compression spring 53 abuts against the valve core side flange 52B.

[0041] Here, the hardness of the lead screw shaft 33 will be explained again. As described above, the lead screw shaft 33 of this embodiment is made of a metal component with a hardness of approximately 300 or higher. Compared to metal sliding components that slide relative to other components, such as the cylindrical component 51 which is a metal sliding component in this embodiment, the hardness of the lead screw shaft 33 is higher. Furthermore, the hardness of the rolling bearing 54 and the compression spring 53 in this embodiment is sometimes higher than the hardness of the lead screw shaft 33. Therefore, the hardness of the lead screw shaft 33 is preferably set to be higher than that of other metal sliding components such as the cylindrical component 51, excluding the rolling bearing 54 and the compression spring 53.

[0042] As described above, the operation of the electric valve 10 begins with... Figure 1 In the open valve state shown, the flange 22 acts as an anti-dislodgement component, thereby suspending the valve core 2 from the lead screw shaft 33 via the connecting body 5. If the stepper motor 3A of the drive unit 3 is rotated from this open valve state, causing the lead screw shaft 33 to descend in the valve-closing direction, the conical front end 21A of the needle-shaped portion 21 approaches the valve seat portion 1G. Furthermore, if the lead screw shaft 33 is further descended from this state, the compression spring 53 is compressed in the axial direction L, thereby exerting a downward force. By applying this force, the front end of the needle-shaped portion 21 is pressed against the valve seat portion 1G, becoming... Figure 2 The valve is in the closed state as shown. In this closed state, the needle-shaped portion 21 and the valve seat portion 1G are pressed along the axis L by the force of the compression spring 53, thereby preventing the needle-shaped portion 21 from floating and maintaining the closed state, even if a higher pressure of the refrigerant acts on the needle-shaped portion 21 from the second connector pipe 12 side. The states from open to closed in this embodiment have been described sequentially in the accompanying drawings. It is self-evident that the same operation is performed in the reverse order from closed to open.

[0043] According to the above embodiment, the electric valve 10 includes a valve body 1A constituting a valve chamber 1D and a valve seat portion 1G, a drive unit 3 that drives a lead screw shaft 33 to rotate, a threaded feed mechanism 4 that causes the lead screw shaft 33 to move forward and backward along the axis L direction as the lead screw shaft 33 rotates, a valve core 2 that can approach or move away from the valve seat portion 1G as the lead screw shaft 33 moves forward and backward, and a connecting body 5 that connects the lead screw shaft 33 and the valve core 2. The threaded feed mechanism 4 has an internal threaded component 42 supported on the valve body 1A. The external threaded portion 33B of the lead screw shaft 33 is threadedly engaged with the internal threaded portion 42A of the internal threaded component 42. The internal threaded component 42 is made of resin containing reinforcing fibers F. Compared with metal sliding components that slide relative to other components, the lead screw shaft 33 is made of a metal component with the highest hardness.

[0044] According to this invention, the lead screw 33 has an external threaded portion 33B that is threadedly engaged with the internal threaded portion 42A of an internal threaded component 42 made of resin containing reinforcing fibers F. Compared to metal sliding components that slide relative to other components (e.g., valve core 2, cylindrical component 51, bearing steel ball 54B, compression spring 53, etc.), this lead screw 33 is made of a metal component with the highest hardness. Here, when the internal threaded portion 42A slides with the external threaded portion 33B, the portion of the resin in the internal threaded portion 42A composed of particularly soft PTFE or similar components first wears away, exposing the reinforcing fibers F. Furthermore, the external threaded portion 33B is cut by the exposed reinforcing fibers F, generating wear debris. Moreover, as described above, since the sliding surface of the internal threaded component 42 contains reinforcing fibers F with an orientation direction intersecting the sliding surface, the exposed reinforcing fibers F are easily hooked by the sliding external threaded portion 33B due to this orientation. Therefore, especially in the external threaded portion 33B, wear debris is more easily generated compared to metal sliding components that slide relative to other components. Furthermore, the portions configured with external threads 33B and internal threads 42A are areas where no refrigerant flows within the electric valve 10, and these portions are not subject to refrigerant flushing. That is, compared to portions with metal sliding parts that slide relative to other components, the portions with external threads 33B and internal threads 42A are more susceptible to the generation of wear debris. Therefore, this easily leads to deterioration in workability and durability. However, according to the structure of the present invention, compared to metal sliding parts that slide relative to other components, the lead screw shaft 33 is constructed from a metal component with the highest hardness. Therefore, even when the external threads 33B and internal threads 42A slide, damage to the metal components by the reinforcing fibers F can be suppressed, and the generation of wear debris can be suppressed, thereby improving workability and durability.

[0045] Furthermore, according to this embodiment, the electric valve 10 of the present invention includes a spring seat component 52, which is a resin component containing reinforcing fibers F, and a cylindrical component 51, which is a metal sliding component, sliding relative to the spring seat component 52. Here, the orientation direction of the reinforcing fibers F in the sliding surface of the internal thread component 42 includes at least a direction intersecting the sliding surface, while the orientation direction of the reinforcing fibers F in the sliding surface of the spring seat component 52 is consistent with the direction along the sliding surface of the spring seat component 52 (axis L direction). According to this orientation, as described above, even if the reinforcing fibers F are exposed, the reinforcing fibers F are unlikely to be hooked by the cylindrical component 51 sliding relative to the spring seat component 52, and wear debris is unlikely to be generated. Moreover, the hardness of the lead screw shaft 33 is higher than the hardness of other metal sliding components such as the cylindrical component 51, except for the rolling bearing 54 and the compression spring 53. That is, compared to the hardness of a metal sliding part (cylindrical part 51) that slides with a resin part (spring seat part 52) ​​that has reinforcing fibers F oriented in a direction intersecting the sliding surface and exposed as described above, but with little impact on sliding, the hardness of a metal sliding part (lead screw shaft 33) that slides with a resin part (internal thread part 42) that has reinforcing fibers F oriented in a direction intersecting the sliding surface and exposed as described above, with a greater impact on sliding, is higher. Therefore, by suppressing damage to the metal part by the reinforcing fibers F and suppressing the generation of wear debris, workability and durability can be improved.

[0046] Furthermore, according to this embodiment, the threaded feed mechanism 4 can house the internal threaded component 42 containing reinforcing fiber F within the fixing component 41 and fix it to the valve body 1A using the protruding edge 41B of the fixing component 41, thus enabling the formation of a high-strength internal threaded component 42 at low cost.

[0047] Next, based on Figure 5 The refrigeration cycle system of the present invention will be described. Figure 5 This is a diagram illustrating the refrigeration cycle system of an embodiment. Figure 5 In the diagram, symbol 100 represents the expansion valve using the electric valve 10 described above, 200 represents the outdoor heat exchanger mounted on the outdoor unit, 300 represents the indoor heat exchanger mounted on the indoor unit, 400 represents the flow path switching valve constituting a four-way valve, and 500 represents the compressor. The expansion valve 100, outdoor heat exchanger 200, indoor heat exchanger 300, flow path switching valve 400, and compressor 500 are connected via conduits as shown in the diagram, forming a heat pump-type refrigeration cycle. Furthermore, illustrations of the energy storage unit, pressure sensor, temperature sensor, etc., are omitted.

[0048] The flow path of the refrigeration cycle is switched by the flow path switching valve 400 to two paths: the flow path for cooling operation and the flow path for heating operation. During cooling operation, such as... Figure 5 As shown by the solid arrow, the refrigerant compressed by the compressor 500 flows from the flow path switching valve 400 into the outdoor heat exchanger 200, which functions as a condenser. The liquid refrigerant flowing out of the outdoor heat exchanger 200 flows through the expansion valve 100 to the indoor heat exchanger 300, which functions as an evaporator.

[0049] On the other hand, during heating operation, such as Figure 5 As shown by the dashed arrow, the refrigerant compressed by the compressor 500 circulates sequentially from the flow path switching valve 400 to the indoor heat exchanger 300, expansion valve 100, outdoor heat exchanger 200, flow path switching valve 400, and compressor 500. The indoor heat exchanger 300 functions as a condenser, and the outdoor heat exchanger 200 functions as an evaporator. The expansion valve 100 depressurizes and expands the liquid refrigerant flowing into the outdoor heat exchanger 200 during cooling operation, or the liquid refrigerant flowing into the indoor heat exchanger 300 during heating operation, and controls the flow rate of the refrigerant.

[0050] Based on this structure, a refrigeration circulation system can be constructed using an electric valve 10 that improves workability and durability by suppressing damage to metal parts by reinforcing fiber F and suppressing the generation of wear debris.

[0051] Furthermore, the present invention is not limited to the above-described embodiments, and includes other structures that can achieve the objectives of the present invention. The present invention also includes the variations shown below. For example, in this embodiment, the cylindrical sliding portion 51A of the cylindrical member 51 is inserted into the cylindrical guide portion 52A of the spring seat member 52, thereby allowing the spring seat member 52 to slide relative to the outer peripheral surface of the cylindrical member 51 along the axis L. However, the inner diameter of the cylindrical sliding portion 51A may be set to be larger than the diameter of the cylindrical guide portion 52A, allowing the spring seat member 52 to slide relative to the inner peripheral surface of the cylindrical member 51 along the axis L. Furthermore, in this embodiment, the cylindrical member 51 is constructed of a metal component, and the spring seat member 52 is constructed of a resin component containing reinforcing fibers F, but this relationship can also be reversed. That is, the cylindrical member 51 may be constructed of a resin component containing reinforcing fibers F, and the spring seat member 52 may be constructed of a metal component with a hardness lower than that of the lead screw shaft 33.

[0052] Furthermore, the part described in this embodiment as "hardness" can also be referred to as "strength". Also, in this embodiment, an electric valve 10 in which the valve core 2 is pressed against the valve seat 1G, i.e., an electric valve 10 in which the valve core 2 is seated or disengaged relative to the valve seat 1G, is described. However, the present invention can also be applied to electric valves in which the valve core 2 only approaches or moves away from the valve seat 1G, and not seated or disengaged relative to the valve seat 1G. Additionally, in the above embodiment, regarding... Figure 1 , Figure 2 The invention has been described in the form of an electric valve, but is not limited to that construction. For example, it can also be applied to electric valves with constructions similar to those in Patent Documents 1 and 2. In the case of Patent Document 1, for example, the resin component is a spring seat, and the metal sliding component that slides relative to the resin component is a valve holder. In the case of Patent Document 2, for example, the sliding component is a valve needle guide. Thus, the sliding components described in Patent Documents 1 and 2 can be used as a comparison object for comparing the hardness with that of the lead screw shaft 33.

[0053] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to the above embodiments. The present invention also includes design changes and the like that that do not depart from the spirit of the present invention.

Claims

1. An electric valve comprising a valve body constituting a valve chamber and a valve seat, a drive unit for rotating a lead screw, a threaded feed mechanism for advancing and retracting the lead screw along an axial direction as the lead screw rotates, a valve core capable of approaching or moving away from the valve seat as the lead screw advances and retracts, and a connecting body connecting the lead screw and the valve core, characterized in that, The aforementioned threaded feed mechanism has an internally threaded component supported on the valve body. The externally threaded portion of the lead screw shaft is threadedly engaged with the internally threaded portion of the internally threaded component. The internally threaded component is made of resin containing reinforcing fibers. The aforementioned lead screw shaft is made of a metal component with a higher hardness than the sliding metal component that slides relative to other components.

2. The electric valve according to claim 1, characterized in that, The other components mentioned above are resin components containing reinforcing fibers. The aforementioned electric valve includes a metal sliding component that slides relative to the aforementioned resin component. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding component that slides relative to the aforementioned resin component.

3. The electric valve according to claim 2, characterized in that, The aforementioned connector includes the aforementioned resin component and a metal sliding component that slides relative to the aforementioned resin component. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding component that slides relative to the aforementioned resin component.

4. The electric valve according to claim 2 or 3, characterized in that, The aforementioned connecting body includes a ball bearing. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding parts that slide relative to the aforementioned resin parts, except for the aforementioned ball bearings.

5. The electric valve according to claim 2 or 3, characterized in that, The aforementioned connecting body includes a compression spring that applies force to the valve core relative to the aforementioned lead screw shaft in the aforementioned axial direction. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding parts that slide relative to the aforementioned resin parts, except for the aforementioned compression spring.

6. The electric valve according to claim 1, characterized in that, The other components mentioned above are resin components containing reinforcing fibers. The aforementioned electric valve includes a metal sliding component that slides along the axial direction relative to the aforementioned resin component. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding component that slides along the axial direction relative to the aforementioned resin component.

7. The electric valve according to claim 6, characterized in that, The aforementioned connector includes the aforementioned resin component and a metal sliding component that slides relative to the aforementioned resin component along the axial direction. The hardness of the aforementioned lead screw shaft is higher than that of the metal sliding component that slides along the axial direction relative to the aforementioned resin component.

8. The electric valve according to any one of claims 1 to 3, characterized in that, The orientation direction of the reinforcing fibers in the sliding surface of the aforementioned internal threaded component includes at least the direction intersecting the aforementioned sliding surface.

9. The electric valve according to any one of claims 1 to 3, characterized in that, The aforementioned connecting body includes a compression spring that applies force to the valve core relative to the aforementioned lead screw shaft in the aforementioned axial direction, a spring seat component that transmits the force of the compression spring, and a metal cylindrical component that slides relative to the aforementioned spring seat component. The hardness of the aforementioned lead screw shaft is higher than that of the metal cylindrical component that slides relative to the aforementioned spring seat component.

10. The electric valve according to claim 9, characterized in that, The aforementioned spring seat component is made of resin containing reinforcing fibers. The orientation direction of the reinforcing fibers in the sliding surface of the aforementioned spring seat component is consistent with the direction along the aforementioned sliding surface.

11. The electric valve according to claim 9, characterized in that, The aforementioned spring seat component slides relative to the inner or outer circumferential surface of the aforementioned cylindrical component along the aforementioned axial direction.

12. The electric valve according to any one of claims 1 to 3, characterized in that, The aforementioned threaded feed mechanism has a metal fixing member that supports the aforementioned internal threaded component on the aforementioned valve body. The fixing member has a cylindrical portion that houses the aforementioned internal threaded component and a protruding edge portion that is fixed to the aforementioned valve body.

13. A refrigeration cycle system, comprising a compressor, an expansion valve, and an evaporator, characterized in that, The electric valve according to any one of claims 1 to 12 is used as the above-mentioned expansion valve.

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