Valve device and refrigeration cycle system

Abstract

To provide a valve gear capable of inhibiting heat stress occurring around a welding part.SOLUTION: A valve gear includes: a valve outer shell body 10 forming a valve chamber S; and a case member 11 which is fixed to the valve outer shell body 10 by welding. The case member 11 is fixedly welded to an opening end edge of the valve outer shell body 10 to form an airtight vessel by the valve outer shell body 10 and the case member 11. A ring shaped part 2B is provided at the radial inner side of a first welding part W1 between the valve outer shell body 10 and the case member 11. The ring shaped part 2B is provided in contact with an inner peripheral surface of the valve outer shell body 10, which is at least one of the valve outer shell body 10 and the case member 11.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a valve device and a refrigeration cycle system. [Background technology]

[0002] As a valve device, there is known an electrically operated valve including a valve body, a valve element, a drive unit, and a case. In this electrically operated valve, the case is welded to the valve body to form an airtight container (see, for example, Patent Documents 1 and 2). In the electrically operated valve described in Patent Document 1, the case is directly welded to the upper opening end face of the valve body, welded with a valve element guide member sandwiched therebetween, or welded with a flange portion of a valve stem holder sandwiched therebetween. In the electrically operated valve described in Patent Document 2, the case is directly welded to the upper opening end face of the valve body, and a fixing fitting of a support member is welded to the inner periphery of the valve body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-211726 A [Patent Document 2] JP2018-150968 Public Relations Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional motor-operated valves, the case and the open end face of the valve body are fixed directly or indirectly by welding. However, when the valve body or case is made thinner to reduce weight, etc., there is a possibility that stress corrosion cracking will occur due to the thermal stress generated at the welded part.

[0005] An object of the present invention is to provide a valve device capable of suppressing thermal stress occurring around a welded portion. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the valve device of the present invention includes a valve outer housing that constitutes a valve chamber, and a case member that is welded and fixed to the valve outer housing. The case member is welded and fixed to the opening edge of the valve outer housing, and an airtight container is formed by the valve outer housing and the case member. Inside the radial direction of the welded part between the valve outer housing and the case member, Metal a ring-shaped member is provided, and the ring-shaped member is provided in contact with the inner peripheral surface of at least one of the valve outer housing and the case member The welded portion is provided within a range of the axial height of the outer circumferential surface of the ring-shaped member, which is a contact portion between the ring-shaped member and the valve outer shell and / or the case member. which is characterized in that.

[0007] According to the present invention as described above, the ring-shaped member provided inside the radial direction of the welded part between the valve outer housing and the case member is in contact with the inner peripheral surface of at least one of the valve outer housing and the case member. Therefore, when welding the valve outer housing and the case member, the heat generated at the welded part can be efficiently transmitted to the ring-shaped member. As a result, it is possible to suppress the occurrence of a rapid temperature gradient between the valve outer housing and the case member due to the accumulation of welding heat at the welded part. Therefore, it is possible to provide a valve device capable of suppressing the thermal stress generated around the welded part. In addition, since the thermal stress can be suppressed, even when the case or the like is made thinner, it is possible to prevent stress corrosion cracking from occurring due to the influence of thermal stress.

[0008] Also, in the vicinity of the welded part, when the wall thickness of the case member is a, the wall thickness of the valve outer housing is b, the wall thickness of the ring-shaped member in the axial direction is c, and the Axis axial height is d, it is preferably set to the relationship of a, b < c, d. According to such a configuration, in the vicinity of the welded part, the wall thickness c of the ring-shaped member is thicker than the wall thickness a of the case member and the wall thickness b of the valve outer housing, and the axial height d of the contact part between the ring-shaped member and the valve outer housing and the case member is higher than the wall thickness a of the case member and the wall thickness b of the valve outer housing. Therefore, the heat of the welded part can be more easily transmitted to the ring-shaped member side than to the valve outer housing side and the case member side. Therefore, compared with the case where the wall thicknesses a, b, c and the height d are different from this configuration, the thermal stress generated around the welded part of the valve body can be further suppressed.

[0009] In this case, it is preferable that the cross-sectional area of ​​the ring-shaped member is larger than the total cross-sectional area of ​​the valve shell and the case member in a predetermined range near the welded portion. With this configuration, the cross-sectional area of ​​the ring-shaped member is larger than the total cross-sectional area of ​​the valve shell and the case member in a predetermined range near the welded portion, so that heat generated around the welded portion can be transferred to the ring-shaped member more efficiently than in a configuration in which the cross-sectional area of ​​the ring-shaped member is smaller than the total cross-sectional area. This makes it possible to further suppress thermal stress generated around the welded portion.

[0010] In addition, it is preferable that the ring-shaped member is press-fitted into the inner periphery of at least one of the valve outer shell and the case member. With this configuration, the ring-shaped member and at least one of the valve outer shell and the case member can be tightly connected by being press-fitted into the inner periphery of at least one of the valve outer shell and the case member, and heat generated around the welded portion can be efficiently transferred to the ring-shaped member.

[0011] The motor-operated valve of the present invention is any one of the valve devices described above, and is characterized in that it comprises the valve outer shell, a valve body movably provided in the valve chamber, a drive unit for driving the valve body, and the case member covering the drive unit, and the ring-shaped member is provided in contact with the inner circumferential surface of at least one of the valve outer shell and the case member. With this configuration, it is possible to provide a motor-operated valve that can suppress thermal stress occurring around the welded portion. Furthermore, since the thermal stress can be suppressed, it is possible to prevent stress corrosion cracking due to the influence of thermal stress even when the case or the like is thinned.

[0012] In this case, it is preferable that the valve outer shell has a valve body that constitutes the valve chamber and the valve seat, and a cylindrical lid member that is fixed to the valve body and extends toward the case member, the case member is welded to the opening edge of the lid member, and the ring-shaped member is provided in contact with the inner circumferential surface of at least one of the lid member and the case member. With this configuration, even in an electrically operated valve in which the valve outer shell is composed of a valve body and a lid member, it is possible to suppress thermal stress occurring around the welded portion.

[0013] The present invention provides a refrigeration cycle system including a compressor, an expansion valve, and an evaporator, characterized in that the valve device or motor-operated valve described above is used as the expansion valve. With this configuration, the refrigeration cycle system can be configured using the valve device or motor-operated valve capable of suppressing thermal stress generated around the welded portion. [Brief description of the drawings]

[0014] [Figure 1] 1 is a vertical cross-sectional view of a motor-operated valve according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a partially enlarged cross-sectional view showing a state before a cover member and a case member that constitute the motor-operated valve are welded together; [Diagram 3] FIG. 4 is a partially enlarged cross-sectional view showing a state after welding of a cover member and a case member that constitute the motor-operated valve. [Figure 4] FIG. 11 is a partially enlarged cross-sectional view of a welded portion in a modified example. [Diagram 5] 1 is a schematic diagram of a refrigeration cycle system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will now be described with reference to Fig. 1 to Fig. 3. As shown in Fig. 1, a motor-operated valve 100 of this embodiment includes a valve housing 1, a fixed member 2, a valve body 3, a drive unit 4, and a connection body 5. The concepts of "upper and lower" in the following description correspond to the upper and lower in the drawing of Fig. 1.

[0016] The valve housing 1 comprises a cylindrical valve shell 10 extending in the direction of axis L, and a case member 11 welded to the upper open edge of the valve shell 10, and the valve shell 10 and case member 11 form an airtight container. The valve shell 10 comprises a cylindrical valve body 10A with a bottom, and a cylindrical lid member 10B connected to the upper end of the valve body 10A. The valve body 10A and the lid member 10B are each formed by pressing or cutting a metal plate made of SUS (stainless steel), brass, or the like, and the interior thereof forms a valve chamber S.

[0017] A first port 10C communicating with the inside and outside of the valve chest S is formed in the side wall of the valve body 10A, and a second port 10D communicating with the inside and outside of the valve chest S is formed in the bottom wall of the valve body 10A. A first joint tube 12 communicating with the valve chest S is attached to the first port 10C, and a second joint tube 13 communicating with the valve chest S is attached to the second port 10D. Refrigerant flows in and out of the first joint tube 12 and the second joint tube 13. The peripheral portion of the second port 10D on the valve chest S side forms a valve seat 10E to which the valve disc 3 approaches or moves away.

[0018] The cover member 10B is a cylindrical member fixed to the valve body 10A and extending toward the case member 11, and is fixed to the upper end of the valve body 10A by crimping and brazing. As shown in FIG. 1, the upper end of the cover member 10B has a smaller outer diameter than the other parts of the cover member 10B. As a result, as shown in FIG. 2, the cover member 10B has a guide surface 10B1 and a step portion 10B2. The guide surface 10B1 is a portion that guides the case member 11 when the case member 11 is fixed to the valve outer shell body 10, and is provided so as to be in sliding contact with the inner peripheral surface 11A of the lower end of the case member 11. This makes it easier to center the case member 11 in the radial direction relative to the valve outer shell body 10 than to guide the case member 11 with a separate member. That is, it is easier to align the axis of the case member 11 and the axis of the valve outer shell body 10 with the axis L.

[0019] The case member 11 is a member that covers the drive unit 4. The case member 11 is formed into an upwardly convex cylindrical cup shape with a wall thickness a (shown in FIG. 3) thinner than the wall thickness b (shown in FIG. 3) of the valve outer shell body 10 in a predetermined range (i.e., in the vicinity of the welded portion) in the vicinity of the first welded portion W1 described later by pressing or cutting a metal plate made of SUS (stainless steel) or brass. As shown in FIG. 2, the case member 11 is provided so that the inner peripheral surface 11A of the lower end portion fits into the guide surface 10B1 of the cover member 10B, and the lower end surface 11B abuts against the step portion 10B2 of the cover member 10B. In this fitted state, the lower end surface 11B and the step portion 10B2 are welded to be fixed to the cover member 10B. That is, the case member 11 is welded and fixed to the open end circle of the cover member 10B. The portion where the lower end surface 11B and the step portion 10B2 come into contact with each other and are welded together is the first welded portion W1 (welded portion) in the present invention.

[0020] The fixed member 2 is disposed in the valve housing 1 and is a member that supports the male threaded portion 43B described later. The fixed member 2 is formed by pressing or cutting a metal plate made of SUS (stainless steel), brass, or the like, and is integrally formed with a cylindrical portion 2A that is provided coaxially with the valve outer shell body 10 and the case member 11 and extends in the direction of the axis L, and a ring-shaped portion 2B (ring-shaped member) that protrudes radially outward from the lower end of the cylindrical portion 2A. The cylindrical portion 2A is provided so as to incorporate a female threaded member 15 that has a female threaded portion 15A that screws into the male threaded portion 43B. The female threaded member 15 is made of a resin mainly composed of PPS (polyphenylene sulfide), and is molded and fixed to the inner circumference of the cylindrical portion 2A by insert molding. The female threaded portion 15A is formed in the center of the female threaded member 15 so as to extend along the axis L.

[0021] The fixing member 2 is disposed in the valve housing 1 at a position such that the ring-shaped portion 2B is radially inward of the first welded portion W1. As shown in FIG. 2, the outer peripheral surface 2B1 of the ring-shaped portion 2B constitutes a contact portion with the cover member 10B and is provided so as to contact the inner peripheral surface of the cover member 10B. That is, the ring-shaped portion 2B is provided radially inward of the first welded portion W1 between the cover member 10B (valve outer shell body 10) and the case member 11, and is provided so as to contact the inner peripheral surface of the valve outer shell body 10, which is at least one of the valve outer shell body 10 and the case member 11. As shown in FIG. 2, a protrusion 2B2 is formed at the upper end of the ring-shaped portion 2B, protruding radially outward over the entire circumference around the axis L.

[0022] In this embodiment, the ring-shaped portion 2B is press-fitted into the inner periphery of the cover member 10B, and is fixed in the valve housing 1 by welding the lower end surface of the protruding portion 2B2 to the upper end surface 10B3 of the cover member 10B. That is, the ring-shaped portion 2B is press-fitted into the inner periphery of the valve outer shell body 10, which is at least one of the valve outer shell body 10 and the case member 11. The portion where the protruding portion 2B2 and the upper end surface 10B3 of the cover member 10B abut and are welded constitutes a second welded portion W2.

[0023] In this embodiment, the ring-shaped portion 2B is press-fitted and welded to the valve outer shell 10, but the fixing method of the ring-shaped portion 2B is not limited to this. The fixing method may be press-fitting only, welding only, or other methods. The fit intersection between the ring-shaped portion 2B and the valve outer shell 10 is not limited to the "tight fit" as in this embodiment, and may be set to be an "intermediate fit" or a "clearance fit". For example, the fit intersection may be set to a "snug fit", which is a type of clearance fit, so that a minute clearance that does not inhibit the heat conduction of the first welded portion W1 and the second welded portion W2 is generated between the inner peripheral surface of the cover member 10B and the outer peripheral surface 2B1 of the ring-shaped portion 2B.

[0024] The ring-shaped portion 2B is formed such that the wall thickness c in the axial direction L (shown in FIG. 3) is thicker than the wall thickness b of the valve outer housing 10 and the wall thickness a of the case member 11 in a predetermined range near the first welding portion W1. Also, the vertical dimension d of the outer peripheral surface 2B1 (i.e., the height in the axial direction L of the contact portion between the ring-shaped portion 2B and the valve outer housing 10) is formed to be larger than the wall thickness a of the case member 11 and the wall thickness b of the valve outer housing 10 in a predetermined range near the first welding portion W1. That is, in the present embodiment, when the wall thickness of the case member 11 is a, the wall thickness of the valve outer housing 10 is b, the wall thickness in the axial direction of the ring-shaped portion 2B is c, and the height in the axial direction L of the contact portion between the ring-shaped portion 2B and the valve outer housing 10 is d in the vicinity of the first welding portion W1, the relationship of a, b < c, d is set. It is still more preferable that a < c, d, b < c, d, and a + b < c, d.

[0025] Incidentally, from the viewpoints of weight reduction and downsizing, the upper limit of the wall thickness c of the ring-shaped portion 2B is preferably set to be 4 times or less the wall thickness b of the valve outer housing 10. The predetermined range near the first welding portion W1 refers to a range where the welding heat of the first welding portion W1 is easily transmitted. Specifically, in the cross-sectional view shown in FIG. 3 (partial enlarged cross-sectional view near the welding portion between the lid member 10B and the case member 11 on the left side of the central axis in the longitudinal cross-section of the electric valve 100), it refers to the range within a radius R centered on the first welding portion W1. In the above cross-sectional view, from the viewpoint of heat transfer, the radius R is preferably set to be 2 to 3 times the wall thickness c of the ring-shaped portion 2B. At this time, it is more preferable that the cross-sectional area of the ring-shaped portion 2B within the radius R is larger than the total cross-sectional area, which is the sum of the cross-sectional areas of the valve outer housing 10 and the case member 11. Although the cross-sectional area has been described, in this case, the same applies when these cross-sectional areas are multiplied by the circumferences of the ring-shaped portion 2B, the valve outer housing 10, and the case member 11 and compared as volumes.

[0026] Inside the valve housing 1, a guide member 14 for guiding the needle portion 31 of the valve body 3 in the axial direction L is installed at the boundary portion between the valve body 10A and the lid member 10B. A guide hole 14a centered on the axis L is formed in the central portion of the guide member 14.

[0027] The valve body 3 is provided so as to be able to approach or move away from the valve seat portion 10E in accordance with the advancement and retreat of a screw shaft 43 described later. That is, the valve body 3 is provided so as to be able to move within the valve chamber S. The valve body 3 includes a needle portion 31 formed in a cylindrical shape extending in the axial direction L, and a flange portion 32 provided at the upper end of the needle portion 31. The upper end side of the needle portion 31 constitutes a reduced diameter portion 31A having a smaller diameter than the lower end side. The needle portion 31 is inserted through a guide hole 14a of the guide member 14 with a small gap (clearance) and is guided to advance and retreat in the axial direction L. The flange portion 32 is a stopper that prevents the needle portion 31 from falling off the connecting body 5 when the connecting body 5 described later and the valve body 3 are connected, and is formed to have a larger diameter than the reduced diameter portion 31A.

[0028] The drive unit 4 is a part that drives the valve body 3, and includes a stepping motor 4A as an electric motor and a stopper mechanism 4B that restricts the rotation of the stepping motor 4A. The stepping motor 4A includes a stator coil 41 that is installed on the outer periphery of the case member 11, a magnet rotor 42 that is installed on the inner periphery of the stator coil 41 across the case member 11 and rotates in the circumferential direction of the axis L, and a screw shaft 43 that serves as a drive shaft that is rotated integrally with the magnet rotor 42. An extension shaft 42A that protrudes upward is provided at the upper end of the magnet rotor 42.

[0029] The upper end of the screw shaft 43 is fixed to the center of the magnet rotor 42 by a welded portion 43A. The screw shaft 43 is made of a metal such as SUS. A male screw portion 43B is formed in the center of the screw shaft 43 in the axial direction L. The male screw portion 43B is screwed into the female screw portion 15A and is screwed while sliding in the circumferential direction along the upper and lower surfaces of the thread. That is, when the magnet rotor 42 rotates, the screw shaft 43 rotates and the male screw portion 43B is screwed, whereby the screw shaft 43 moves back and forth within the valve housing 1.

[0030] In this way, the female thread portion 15A and the male thread portion 43B form a screw feed mechanism, and the screw shaft 43 advances and retreats in the direction of the axis L as the screw shaft 43 rotates due to the drive of the stepping motor 4A. The lower end of the screw shaft 43 is formed to have a larger straightness than other parts of the screw shaft 43, forming an expanded diameter portion 43C. A holding member 44 is attached between the male thread portion 43B and the expanded diameter portion 43C of the screw shaft 43, covering the outer periphery of the screw shaft 43 in the circumferential direction.

[0031] The stopper mechanism 4B includes a guide 45 suspended from the ceiling of the case member 11, a guide wire body 46 spirally wound around the outer circumference of the guide 45, and a movable slider 47 guided by the guide wire body 46 to move in the vertical direction. The guide 45 is arranged so that its central axis is coaxial with the central axis of the screw shaft 43, and extends in the direction of the axis L. The movable slider 47 is arranged so that it winds around the guide wire body 46 while fitting into the spiral groove of the guide wire body 46. The movable slider 47 is formed with a claw portion 47A protruding radially outward from the guide 45. The claw portion 47A abuts against the extension shaft 42A provided on the magnet rotor 42 in the circumferential direction of the axis L. With this configuration, the movable slider 47 is rotated in the circumferential direction of the guide 45 along the groove of the guide wire body 46 as the magnet rotor 42 rotates, thereby allowing the movable slider 47 to move in the vertical direction.

[0032] The upper end stopper 46A and the lower end stopper 46B are formed at the upper end and the lower end of the guide wire body 46, which come into contact with the claw portion 47A of the movable slider 47. The upper end stopper 46A and the lower end stopper 46B restrict the rotation of the claw portion 47A that comes into contact with them. With this configuration, the movable slider 47 that comes into contact with the upper end stopper 46A cannot rotate any further. When the rotation of the movable slider 47 is restricted, the rotation of the magnet rotor 42 that rotates with the movable slider 47 is restricted. That is, the upper end stopper 46A functions as a stopper that determines the uppermost position of the magnet rotor 42. Similarly, when the claw portion 47A comes into contact with the lower end stopper 46B, the rotation of the movable slider 47 is restricted, and the rotation of the magnet rotor 42 is restricted. That is, the lower end stopper 46B functions as a stopper that determines the lowest end position of the magnet rotor 42.

[0033] The connecting body 5 is a member that connects the valve body 3 and the drive unit 4 in the axial direction L, and includes a metallic cylindrical member 51 arranged on the screw shaft 43 side, a resin spring bearing member 52 (resin member) arranged on the valve body 3 side, and a metallic compression spring 53 interposed between the cylindrical member 51 and the spring bearing member 52. The cylindrical member 51 is made of metal such as SUS, and includes a cylindrical sliding portion 51A extending in the axial direction L, and a screw shaft side flange portion 51B protruding radially outward from the upper end portion of the cylindrical sliding portion 51A. The cylindrical sliding portion 51A is arranged with a predetermined gap in the radial direction from the screw shaft 43. The screw shaft side flange portion 51B is configured to abut against the upper end portion of the compression spring 53.

[0034] A rolling bearing 54 (ball bearing) is installed in the center of the inner peripheral wall of the cylindrical sliding part 51A in the direction of the axis L. The rolling bearing 54 is a bearing that connects the screw shaft 43 and the cylindrical member 51 so as to be capable of relative rotation, and is configured with an inner ring 54A, steel balls 54B, and an outer ring 54C. The inner ring 54A covers the outer periphery of the screw shaft 43 from the lower end of the above-mentioned holding member 44 to just before the enlarged diameter part 43C. The outer ring 54C is fixed to the cylindrical sliding part 51A by a retaining ring 55 that is press-fitted into the upper end of the inner peripheral surface of the cylindrical sliding part 51A in the direction of the axis L. As a result, the screw shaft 43 and the cylindrical member 51 are connected via the rolling bearing 54. A connection hole 51A2 whose central axis is coaxial with the axis L is formed through the center of the bottom wall of the cylindrical sliding part 51A. The connection hole 51A2 is a hole into which a connection tube portion 56, which will be described later, is inserted.

[0035] The spring receiving member 52 is a member that transmits the biasing force of the compression spring 53 in the axial direction L, and is formed by injection molding, cutting, or the like using a resin mainly composed of PPS (polyphenylene sulfide). The spring receiving member 52 includes a cylindrical guide portion 52A extending in the axial direction L, and a valve body side flange portion 52B that protrudes 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 above-mentioned cylindrical sliding portion 51A, and is provided so that the cylindrical sliding portion 51A can be inserted therein. With this configuration, the inner peripheral surface of the spring receiving member 52 slides against the outer peripheral surface of the cylindrical sliding portion 51A along the axial direction L. The valve body side flange portion 52B is configured to abut against the lower end of the compression spring 53.

[0036] A through hole 52A1 whose center line is coaxial with the axis L is formed in the center of the bottom wall of the cylindrical guide portion 52A, and a connecting cylinder portion 56 is inserted into the through hole 52A1. The connecting cylinder portion 56 is a member that connects the cylindrical member 51 and the spring receiving member 52 and also connects the spring receiving member 52 and the valve body 3, and extends in the direction of the axis L from inside to outside the cylindrical guide portion 52A. A groove portion 56A recessed radially inward is formed in the outer portion of the cylindrical guide portion 52A at the lower end of the side wall of the connecting cylinder portion 56. A fixing ring 57 formed in a C-shape is fitted radially into the groove portion 56A.

[0037] The fixing ring 57 is fitted toward the drive unit 4 in a recess 52A2 formed on the lower end surface of the bottom wall of the cylindrical guide portion 52A and opening toward the second port 10D. When the fixing ring 57 is fitted into the recess 52A2, the connection tube portion 56 is connected to the spring receiving member 52 by the repulsive force of the compression spring 53 pressed toward the drive unit 4 via the spring receiving member 52. An upper end flange 56B is formed at the upper end of the connection tube portion 56, and the spring receiving member 52 and the cylindrical member 51 are connected by the upper end flange 56B being caught on the edge of the above-mentioned connection hole 51A2. Although not shown, a part of the side wall of the connection tube portion 56 is cut out from the upper end to the lower end, and an opening communicating with the inside of the tube of the connection tube portion 56 is formed by this cutout.

[0038] The dimension of the inner diameter of the connecting tube portion 56 is set to be larger than the diameter of the reduced diameter portion 31A in the needle portion 31 described above and smaller than the diameter of the flange portion 32. The dimension of the connecting tube portion 56 in the axial direction L is formed to be approximately the same as the dimension of the reduced diameter portion 31A in the axial direction L. The dimension of the opening of the side wall of the connecting tube portion 56 in the width direction intersecting the axial direction L is formed to be approximately the same as the diameter of the reduced diameter portion 31A. The reduced diameter portion 31A is inserted into the connecting tube portion 56 from the radial direction through the opening. With this configuration, the reduced diameter portion 31A is inserted into the connecting tube portion 56 with a radial gap, the flange portion 32 acts as a retainer, and the valve body 3 is prevented from falling off below the connecting tube portion 56, so that the valve body 3 and the spring receiving member 52 are connected.

[0039] The compression spring 53 biases the valve body 3 in the axial direction L relative to the screw shaft 43. The compression spring 53 is made of a metal member and is interposed between the cylindrical member 51 and the spring receiving member 52 along the axial direction L. An upper end of the compression spring 53 abuts against the screw shaft side flange portion 51B, and a lower end of the compression spring 53 abuts against the valve body side flange portion 52B.

[0040] The operation of the motor-operated valve 100 described above is as follows: first, in the valve open state shown in Fig. 1, the flange portion 32 prevents the valve body 3 from coming off, and the valve body 3 is suspended from the screw shaft 43 via the connector 5. When the stepping motor 4A of the drive unit 4 is driven to rotate from this valve open state, and the screw shaft 43 is lowered in the valve closing direction, the tip of the needle portion 31 approaches the valve seat portion 10E. When the screw shaft 43 is further lowered from this state, the compression spring 53 is compressed in the direction of the axis L, and a downward biasing force is applied, and this biasing force presses the tip of the needle portion 31 against the valve seat portion 10E, resulting in a valve closed state. In this valve closed state, the needle portion 31 and the valve seat portion 10E are pressed in the axial direction L by the biasing force of the compression spring 53, so that even if a high pressure of the refrigerant acts on the needle portion 31 from the second joint pipe 13 side, the needle portion 31 is prevented from floating up and the valve closed state can be maintained. Although the valve open to valve closed states of this embodiment have been described in order above, it goes without saying that the reverse operation from valve closed to valve open is performed in the same order. In addition, in this embodiment, the tip of the needle portion 31 is configured to be pressed against the valve seat portion 10E, but the valve does not necessarily have to be closed, and the present invention can also be applied to a flow control valve in which the needle portion 31 simply approaches and moves away from the valve seat portion 10E.

[0041] When assembling the motor-operated valve 100, the lower end of the case member 11 is fitted to the upper end of the valve shell 10 as shown in FIG. 2. Specifically, the case member 11 is fitted into the cover member 10B while the inner peripheral surface 11A of the lower end of the case member 11 is brought into sliding contact with the guide surface 10B1 of the cover member 10B, so that the lower end surface 11B of the case member 11 abuts against the step portion 10B2 of the cover member 10B. Then, in this fitted state, the lower end surface 11B and the step portion 10B2 are welded together as shown in FIG. 3. At this time, the heat generated at the first welded portion W1 is transferred to the valve shell 10 side, the case member 11 side, and the ring-shaped portion 2B side as shown by the arrows in FIG. 3. As described above, the valve outer shell 10, the case member 11, and the ring-shaped portion 2B are each made of a metal such as SUS, and the cross-sectional area (or the volume obtained by multiplying the cross-sectional area by the circumferential length) of the cross-sectional view shown in FIG. 3 in a predetermined range (described above) in the vicinity of the first welded portion W1 is such that the cross-sectional area of ​​the ring-shaped portion 2B (or the volume obtained by multiplying the cross-sectional area of ​​the ring-shaped portion 2B by the circumferential length of the ring-shaped portion 2B) is 1 / 2 the total cross-sectional area of ​​the valve outer shell 10 and the case member 11 (or the cross-sectional area of ​​the valve outer shell 10 multiplied by the circumferential length of the valve outer shell 10). Since the vertical dimension d of the outer peripheral surface 2B1 (i.e., the height in the axial direction of the axis L of the contact portion between the ring-shaped portion 2B and the valve outer shell 10) is greater than the wall thickness a of the case member 11 and the wall thickness b of the valve outer shell 10 in a predetermined range near the first welded portion W1, the heat is most efficiently transferred to the ring-shaped portion 2B. In this way, the heat generated at the first welded portion W1 is efficiently transferred to the ring-shaped portion 2B.

[0042] According to the above embodiment, the ring-shaped portion 2B provided radially inside the first welded portion W1 (welded portion) between the valve outer shell 10 and the case member 11 is in contact with the inner circumferential surface of the valve outer shell 10, which is at least one of the valve outer shell 10 and the case member 11, so that the heat generated at the first welded portion W1 when the valve outer shell 10 and the case member 11 are welded can be efficiently transferred to the ring-shaped portion 2B. This prevents the welding heat from staying at the first welded portion W1, which causes a sudden temperature gradient between the valve outer shell 10 and the case member 11. Therefore, it is possible to provide a valve device that can suppress the thermal stress generated around the welded portion. In addition, since the thermal stress can be suppressed, even if the case member 11 or the like is thinned, it is possible to prevent stress corrosion cracking due to the influence of thermal stress.

[0043] Furthermore, in the vicinity of the first welded zone W1, the thickness c of the ring-shaped portion 2B is thicker than the thickness a of the case member 11 and the thickness b of the valve shell 10, and the height d in the axial direction L of the contact portion between the ring-shaped portion 2B and the valve shell 10 and the case member 11 is greater than the thickness a of the case member 11 and the thickness b of the valve shell 10, so that the heat of the first welded zone W1 can be more easily transferred to the ring-shaped portion 2B side than to the valve shell 10 side and the case member 11 side. Therefore, compared to a case where the thicknesses a, b, c and the height d are different from this configuration, the thermal stress generated around the first welded zone W1 of the valve body 10A can be further suppressed.

[0044] In addition, in a predetermined range near the first welded zone W1, the cross-sectional area of ​​the ring-shaped portion 2B can be made larger than the combined cross-sectional area of ​​the valve shell 10 and the case member 11, so that heat generated around the first welded zone W1 can be transferred to the ring-shaped portion 2B more efficiently than in a configuration in which the cross-sectional area of ​​the ring-shaped portion 2B is smaller than this combined cross-sectional area, thereby making it possible to further suppress thermal stress generated around the welded zone.

[0045] In addition, since the ring-shaped portion 2B can be pressed into the inner circumference of at least one of the valve outer shell 10 and the case member 11, the ring-shaped portion 2B can be tightly connected to at least one of the valve outer shell 10 and the case member 11, and heat generated around the first welded portion W1 can be efficiently transferred to the ring-shaped portion 2B.

[0046] Next, a modified example of the present invention will be described with reference to Fig. 4. Fig. 4 is a partially enlarged cross-sectional view of the first welded part W1 in the modified example. The motor-operated valve 100 in Fig. 4(A) is different from the motor-operated valve 100 of this embodiment in that the ring-shaped part 2B does not have a protruding part 2B2, and the upper part of the outer circumferential surface 2B1 and the inner circumferential surface of the cover member 10B are welded to form the second welded part W2.

[0047] The motor-operated valve 100 of FIG. 4(B) is different from the motor-operated valve 100 of the present embodiment in that it does not have the protruding portion 2B2, as in FIG. 4(A). Also, the outer diameter of the upper end of the cover member 10B is not smaller than the outer diameter of the other parts of the cover member 10B, and the outer diameter of the lower end of the case member 11 is smaller than the outer diameter of the other parts of the case member 11, which is different from the motor-operated valve 100 of the present embodiment. That is, the case member 11 is provided with a guide surface 11B1 and a step portion 11B2, which are equivalent to the guide surface 10B1 and the step portion 10B2 of the present embodiment, so that the case member 11 guides the valve outer shell 10. The step portion 11B2 and the upper end surface 10B3 of the cover member 10B are welded to form a first welded portion W1. The inner peripheral surface of the case member 11 and the outer peripheral surface 2B1 of the ring-shaped portion 2B are welded to form a second welded portion W2. In this way, the ring-shaped portion 2B is provided radially inward of the first welded portion W1 between the cover member 10B (valve shell body 10) and the case member 11, and is provided so as to abut against the inner circumferential surface of the case member 11, which is at least one of the valve shell body 10 and the case member 11. In this case as well, the vertical dimension d of the outer circumferential surface 2B1 of the ring-shaped portion 2B (i.e., the height in the axial direction L of the contact portion between the ring-shaped portion 2B and the case member 11) is greater than the above-mentioned wall thicknesses a and b.

[0048] In the motor-operated valve 100 of Fig. 4(C), the guide surface 10B1 and the step portion 10B2 are not provided, and the upper end surface 10B3 of the cover member 10B and the lower end surface 11B of the case member 11 are welded to form the first welded portion W1, and the ring-shaped portion 2B is welded to the case member 11 so that the ring-shaped portion 2B is in contact from the cover member 10B to the case member 11 to form the second welded portion W2. That is, in the above-mentioned embodiment and modified example, the heat of the first welded portion W1 is indirectly transferred to the ring-shaped portion 2B via the valve outer shell 10 or the case member 11, whereas in this modified example, the above-mentioned heat is directly or indirectly transferred from the first welded portion W1 to the ring-shaped portion 2B depending on the depth of the first welded portion W1 (the length of the welded portion in the plate thickness direction of the cover member 10B and the case member 11). In addition, in FIG. 4(C), the second welded portion W2 is provided on the upper side of the outer circumferential surface 2B1 of the ring-shaped portion 2B, but the second welded portion W2 may be provided on the lower side of the outer circumferential surface 2B1.

[0049] As described above, in one embodiment and three modified examples, the ring-shaped portion 2B (ring-shaped member) is provided radially inside the first welded portion W1 between the cover member 10B (valve shell 10) and the case member 11. Specifically, in one embodiment and the first modified example (shown in FIG. 4A), the ring-shaped portion 2B is provided radially inside the first welded portion W1, and the first welded portion W1 is provided within an axial range of an axial height d on the outer peripheral surface 2B1 of the ring-shaped portion 2B, which is a contact portion between the ring-shaped portion 2B and the cover member 10B. In the second modified example (shown in FIG. 4B), the ring-shaped portion 2B is provided radially inside the first welded portion W1, and the first welded portion W1 is provided within an axial range of an axial height d on the outer peripheral surface 2B1 of the ring-shaped portion 2B, which is a contact portion between the ring-shaped portion 2B and the case member 11. In a third modified example (shown in FIG. 4C), the ring-shaped portion 2B is provided radially inward of the first welded portion W1, and the first welded portion W1 is provided within an axial range of the axial height d on the outer circumferential surface 2B1 of the ring-shaped portion 2B, which is a contact portion between the ring-shaped portion 2B and both the cover member 10B and the case member 11. With this configuration, when welding the cover member 10B and the case member 11, the first welded portion W1 and the ring-shaped portion 2B are closer than in a configuration in which the first welded portion W1 is not provided within the axial range of the axial height d, so that welding heat can be transferred to the ring-shaped portion 2B more efficiently.

[0050] Next, the refrigeration cycle system of the present invention will be described with reference to Fig. 5. Fig. 5 is a diagram showing a refrigeration cycle system of an embodiment. In Fig. 5, reference numeral 1000 denotes an expansion valve using the motor-operated valve 100 of the embodiment, 2000 denotes an outdoor heat exchanger mounted on an outdoor unit, 3000 denotes an indoor heat exchanger mounted on an indoor unit, 4000 denotes a flow path switching valve constituting a four-way valve, and 5000 denotes a compressor. The expansion valve 1000, the outdoor heat exchanger 2000, the indoor heat exchanger 3000, the flow path switching valve 4000, and the compressor 5000 are each connected by a conduit as shown in the figure, constituting a heat pump type refrigeration cycle. Note that an accumulator, a pressure sensor, a temperature sensor, and the like are omitted from the illustration.

[0051] The flow path of the refrigeration cycle is switched between two flow paths, one for cooling operation and the other for heating operation, by the flow path switching valve 4000. During cooling operation, as shown by the solid arrows in Fig. 5, the refrigerant compressed by the compressor 5000 flows from the flow path switching valve 4000 into the outdoor heat exchanger 2000, which functions as a condenser, and the liquid refrigerant flowing out of the outdoor heat exchanger 2000 flows through the expansion valve 1000 to the indoor heat exchanger 3000, which functions as an evaporator.

[0052] 5, the refrigerant compressed by the compressor 5000 is circulated from the flow path switching valve 4000 to the indoor heat exchanger 3000, the expansion valve 1000, the outdoor heat exchanger 2000, the flow path switching valve 4000, and then to the compressor 5000, with the indoor heat exchanger 3000 functioning as a condenser and the outdoor heat exchanger 2000 functioning as an evaporator. The expansion valve 1000 reduces the pressure and expands the liquid refrigerant flowing in from the outdoor heat exchanger 2000 side during cooling operation, or the liquid refrigerant flowing in from the indoor heat exchanger 3000 side during heating, and further controls the flow rate of the refrigerant.

[0053] According to this configuration, a refrigeration cycle system can be constructed using the motor-operated valve 100 that can prevent stress corrosion cracking due to thermal stress even when the case member 11, etc. are made thin-walled.

[0054] The present invention is not limited to the above embodiment, but includes other configurations that can achieve the object of the present invention, and the following modified examples are also included in the present invention. For example, in this embodiment, the valve shell 10 is composed of the valve body 10A and the cover member 10B, but the valve body 10A and the cover member 10B do not necessarily need to be provided separately, and may be provided integrally, or the cover member 10B may be omitted.

[0055] In the present embodiment, the drive unit 4 includes a screw feed mechanism consisting of the female screw portion 15A of the female screw member 15 built into the fixed member 2 and the male screw portion 43B formed on the screw shaft 43, and when the magnet rotor 42 rotates, the male screw portion 43B is screwed, so that the screw shaft 43 moves forward and backward together with the valve body 3 in the valve housing 1. However, the screw shaft 43 on which the male screw portion 43B is formed may be fixed so as to be rotatable about the axis L and immovable in the vertical direction, and the female screw member 15 may be provided so as to be movable in the vertical direction instead of being built into the fixed member 2, and the female screw member 15 and the valve body 3 may be connected. In this configuration, when the magnet rotor 42 rotates, the female screw portion 15A is screwed, so that the valve body 3 moves forward and backward in the valve housing 1. In addition to the motor-operated valve 100 of the above embodiment and modified example, the valve device of the present invention may be applied to various valve devices such as solenoid valves and thermostatic expansion valves.

[0056] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0057] S valve chamber W1 First weld (weld) 2B Ring-shaped part (ring-shaped member) 10 Valve shell 11 Case material 100 Motor-operated valve (valve device)

Claims

1. A valve device comprising: a valve shell that defines a valve chamber; and a case member that is welded to the valve shell, the case member being welded to an opening edge of the valve shell, such that an airtight container is formed by the valve shell and the case member, a metal ring-shaped member is provided radially inside a welded portion between the valve outer shell and the case member, the ring-shaped member being provided in contact with an inner circumferential surface of at least one of the valve outer shell and the case member; a valve device characterized in that the welded portion is provided within a range of axial height on the outer peripheral surface of the ring-shaped member, which is the contact portion between the ring-shaped member and the valve outer shell and / or the case member.

2. 2. The valve device according to claim 1, wherein, in the vicinity of the welded portion, the wall thickness of the case member is a, the wall thickness of the valve outer shell is b, the axial thickness of the ring-shaped member is c, and the axial height is d, the relationship of a, b < c, d is satisfied.

3. 3. The valve device according to claim 2, wherein the cross-sectional area of ​​the ring-shaped member in a predetermined range near the welded portion is larger than the combined cross-sectional area of ​​the valve shell and the case member.

4. 4. The valve device according to claim 1, wherein the ring-shaped member is press-fitted into an inner periphery of at least one of the valve outer shell and the case member.

5. The valve device according to any one of claims 1 to 4, wherein the motor-operated valve is the valve shell; a valve body movably provided within the valve chamber; a drive unit that drives the valve body; and the case member that covers the drive unit, The motor-operated valve, wherein the ring-shaped member is provided in contact with an inner circumferential surface of at least one of the valve outer shell and the case member.

6. the valve shell includes a valve body that constitutes the valve chamber and the valve seat, and a cylindrical lid member that is fixed to the valve body and extends toward the case member, the case member being welded to an opening edge of the lid member; 6. The motor-operated valve according to claim 5, wherein the ring-shaped member is provided in contact with an inner circumferential surface of at least one of the cover member and the case member.

7. A refrigeration cycle system including a compressor, an expansion valve, and an evaporator, wherein the valve device according to any one of claims 1 to 4, or the motor-operated valve according to claim 5 or 6 is used as the expansion valve.

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