JP7653385B2 - Valve device and refrigeration cycle system - Google Patents

Description

The present invention relates to a valve device and a refrigeration cycle system.

A known valve device is an electrically operated valve that includes 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 welded directly to the upper opening end face of the valve body, welded with a valve element guide member sandwiched between them, or welded with a flange portion of the valve stem holder sandwiched between them. In the electrically operated valve described in Patent Document 2, the case is welded directly to the upper opening end face of the valve body, and a fixing bracket for a support member is welded to the inner periphery of the valve body.

JP 2016-211726 A JP2018-150968Publication

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 are thinned to reduce weight, etc., there is a possibility that stress corrosion cracking may occur due to the thermal stress generated at the welded part.

The object of the present invention is to provide a valve device that can suppress thermal stress occurring around the welded portion.

In order to solve the above problems and achieve the object, the valve device of the present invention comprises a valve shell that constitutes a valve chamber, and a case member that is welded to the valve shell, and the case member is welded to the opening edge of the valve shell to form an airtight container, and is characterized in that a metal ring-shaped member is provided radially inward of the weld between the valve shell and the case member, the ring-shaped member is provided in contact with the inner circumferential surface of at least one of the valve shell and the case member , and the weld is provided within a range of axial heights of the outer circumferential surface of the ring-shaped member, which is the contact portion between the ring-shaped member and the valve shell and/or the case member .

According to the present invention, the ring-shaped member provided radially inside the welded portion between the valve outer shell and the case member is in contact with the inner circumferential surface of at least one of the valve outer shell and the case member, so that the heat generated at the welded portion when the valve outer shell and the case member are welded can be efficiently transferred to the ring-shaped member. This prevents the welding heat from remaining at the welded portion, which would cause a sudden temperature gradient to occur between the valve outer shell and the case member. Therefore, it is possible to provide a valve device that can suppress the thermal stress generated around the welded portion. Furthermore, because 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, etc. is thin-walled.

In addition, in the vicinity of the welded portion, when the thickness of the case member is a, the thickness of the valve shell is b, the axial thickness of the ring-shaped member is c, and the axial height is d, it is preferable that the relationship of a, b < c, d is satisfied. According to this configuration, in the vicinity of the welded portion, the thickness c of the ring-shaped member is thicker than the thickness a of the case member and the thickness b of the valve shell, and the axial height d of the contact portion between the ring-shaped member, the valve shell, and the case member is higher than the thickness a of the case member and the thickness b of the valve shell, so that the heat of the welded portion can be more easily transferred to the ring-shaped member side than to the valve shell side and the case member side. Therefore, compared to the case where the thicknesses a, b, c and the height d are different from this configuration, the thermal stress generated around the welded portion of the valve body can be further suppressed.

In this case, it is preferable that the cross-sectional area of the ring-shaped member is larger than the combined 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 combined 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 compared to a configuration in which the cross-sectional area of the ring-shaped member is smaller than this combined cross-sectional area. This makes it possible to further suppress thermal stress generated around the welded portion.

It is also 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 is press-fitted into the inner periphery of at least one of the valve outer shell and the case member, so that the ring-shaped member and at least one of the valve outer shell and the case member can be tightly connected, and heat generated around the welded portion can be efficiently transferred to the ring-shaped member.

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 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, and the ring-shaped member is provided in contact with the inner circumferential surface of at least one of the valve 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, etc. is thin-walled.

In this case, it is preferable that the valve outer shell has a valve body that constitutes the valve chamber and 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, it is possible to suppress thermal stress occurring around the welded portion even in an electrically operated valve in which the valve outer shell is composed of a valve body and a lid member.

The refrigeration cycle system of the present invention is a refrigeration cycle system including a compressor, an expansion valve, and an evaporator, characterized in that any of the valve devices or motor-operated valves described above are used as the expansion valve. With this configuration, a refrigeration cycle system can be configured using a valve device or motor-operated valve that can suppress thermal stress generated around the welded portion.

1 is a vertical cross-sectional view of a motor-operated valve according to an embodiment of the present invention; 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; FIG. 4 is a partially enlarged cross-sectional view showing a state after a cover member and a case member that constitute the motor-operated valve are welded together; FIG. 11 is a partially enlarged cross-sectional view of a welded portion in a modified example. 1 is a schematic diagram of a refrigeration cycle system according to an embodiment of the present invention.

One embodiment of the present invention will be described below with reference to Figs. 1 to 3. As shown in Fig. 1, the motor-operated valve 100 of this embodiment comprises a valve housing 1, a fixed member 2, a valve body 3, a drive unit 4, and a connection body 5. Note that the concept of "upper and lower" in the following description corresponds to the upper and lower in the drawing of Fig. 1.

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 opening 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) or brass, and the inside forms the valve chamber S.

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

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 10, and is provided so as to slide against the inner circumferential surface 11A of the lower end of the case member 11. In this way, it is easier to center the case member 11 in the radial direction relative to the valve outer shell 10 than to guide the case member 11 with a separate member. In other words, it is easier to align the axis of the case member 11 and the axis of the valve outer shell 10 with the axis L.

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) that is thinner than the wall thickness b (shown in FIG. 3) of the valve outer shell 10 in a predetermined range (i.e., near the welded portion) near 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 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 part where the lower end surface 11B and the step portion 10B2 come into contact and are welded is the first welded portion W1 (welded portion) in this invention.

The fixing member 2 is disposed in the valve housing 1 and is a member that supports the male threaded portion 43B described later. The fixing member 2 is formed by pressing or cutting a metal plate made of SUS (stainless steel) or brass, etc., and is integrally formed with a cylindrical portion 2A that is arranged coaxially with the valve outer shell 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 whose main component is 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 so as to extend along the axis L at the center of the female threaded member 15.

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 10) and the case member 11, and is provided so as to contact the inner peripheral surface of the valve outer shell 10, which is at least one of the valve outer shell 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 around the entire circumference around the axis L.

In this embodiment, the ring-shaped portion 2B is pressed into the inner circumference of the lid 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 lid member 10B. That is, the ring-shaped portion 2B is pressed into the inner circumference of the valve outer shell 10, which is at least one of the valve outer shell 10 and the case member 11. The portion where the protruding portion 2B2 and the upper end surface 10B3 of the lid member 10B abut and are welded constitutes the second welded portion W2.

In this embodiment, the ring-shaped portion 2B is pressed and welded to the valve outer shell 10, but the method of fixing the ring-shaped portion 2B is not limited to this. The fixing method may be only pressing, only welding, or other methods. The fit intersection between the ring-shaped portion 2B and the valve outer shell 10 is not limited to a "tight fit" as in this embodiment, but 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 small clearance is generated between the inner peripheral surface of the cover member 10B and the outer peripheral surface 2B1 of the ring-shaped portion 2B that does not inhibit the heat conduction of the first welded portion W1 and the second welded portion W2.

The ring-shaped portion 2B is formed so that the thickness c (shown in FIG. 3) in the axial direction is thicker than the thickness b of the valve shell 10 and the thickness a of the case member 11 in the predetermined range near the first welded portion W1. In addition, the vertical dimension d of the outer peripheral surface 2B1 (i.e., the height in the axial direction of the contact portion between the ring-shaped portion 2B and the valve shell 10) is formed so that the vertical dimension d (i.e., the height in the axial direction of the contact portion between the ring-shaped portion 2B and the valve shell 10) is larger than the thickness a of the case member 11 and the thickness b of the valve shell 10 in the predetermined range near the first welded portion W1. That is, in this embodiment, when the thickness of the case member 11 is a, the thickness of the valve shell 10 is b, the axial thickness of the ring-shaped portion 2B is c, and the height in the axial direction of the contact portion between the ring-shaped portion 2B and the valve shell 10 is d, the relationship is set to a, b < c, d. It is even more preferable to set a<c,d and b<c,d, and a+b<c,d.

In addition, from the viewpoint of weight reduction and compactness, the upper limit of the thickness c of the ring-shaped portion 2B is preferably 4 times or less than the thickness b of the valve outer shell 10. In addition, the predetermined range in the vicinity of the first welded portion W1 refers to the range in which the welding heat of the first welded portion W1 is easily transmitted, and specifically, in the cross-sectional view shown in FIG. 3 (partially enlarged cross-sectional view in the vicinity of the welded portion between the cover member 10B and the case member 11 on the left side of the central axis in the longitudinal section of the motor-operated valve 100), refers to the range within the radius R centered on the first welded portion W1. In the above cross-sectional view, it is preferable that the radius R is, for example, 2 to 3 times the thickness c of the ring-shaped portion 2B from the viewpoint of heat transmission. In this case, 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 shell 10 and the case member 11. Although the cross-sectional areas have been described above, in this case, the volumes can be compared by multiplying these cross-sectional areas by the circumferential lengths of the ring-shaped portion 2B, the valve outer shell 10, and the case member 11.

In the valve housing 1, a guide member 14 is installed at the boundary between the valve body 10A and the cover member 10B to guide the needle portion 31 of the valve body 3 in the direction of the axis L. A guide hole 14a is formed in the center of the guide member 14, centered on the axis L.

The valve body 3 is provided so that it can approach or move away from the valve seat portion 10E as the screw shaft 43 described later moves forward and backward. That is, the valve body 3 is provided so that it can 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 the guide hole 14a of the guide member 14 with a small gap (clearance) and is guided forward and backward in the axial direction L. The flange portion 32 is a stopper that prevents the needle portion 31 from falling out of 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.

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.

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 threaded portion 43B is formed in the center of the axis L direction of the screw shaft 43. The male threaded portion 43B screws into the female threaded portion 15A and is screwed while sliding circumferentially along the upper and lower surfaces of the thread. In other words, when the magnet rotor 42 rotates, the screw shaft 43 rotates and the male threaded portion 43B is screwed, so that the screw shaft 43 moves back and forth within the valve housing 1.

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

The stopper mechanism 4B includes a guide 45 that hangs down from the ceiling of the case member 11, a guide wire body 46 that spirally winds around the outer circumference of the guide 45, and a movable slider 47 that is guided by the guide wire body 46 and moves 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 that protrudes radially outward from the guide 45. The claw portion 47A abuts against the above-mentioned 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, and the movable slider 47 is thereby movable in the vertical direction.

At the upper end and lower end of the guide wire body 46, an upper end stopper 46A and a lower end stopper 46B are formed, 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.

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 a 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 that protrudes radially outward from the upper end of the cylindrical sliding portion 51A. The cylindrical sliding portion 51A is arranged with a predetermined radial gap from the screw shaft 43. The screw shaft side flange portion 51B is configured to abut the upper end of the compression spring 53.

A rolling bearing 54 (ball bearing) is installed in the center of the axis L direction on the inner peripheral wall of the cylindrical sliding part 51A. The rolling bearing 54 is a bearing that connects the screw shaft 43 and the cylindrical member 51 so that they can rotate relative to each other, and is composed of 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 pressed into the upper end of the axis L direction on the inner peripheral surface of the cylindrical sliding part 51A. As a result, the screw shaft 43 and the cylindrical member 51 are connected via the rolling bearing 54. A connection hole 51A2 whose center axis is coaxial with the axis L is formed through the center of the bottom wall of the cylindrical sliding part 51A. This connection hole 51A2 is the hole into which the connection tube portion 56, described below, is inserted.

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 whose main component is 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 that is 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 into it. 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.

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 tube portion 56 is inserted into the through hole 52A1. The connecting tube 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 the inside to the outside of the cylindrical guide portion 52A. A groove portion 56A that is recessed radially inward is formed in the outer part of the cylindrical guide portion 52A at the lower end of the side wall of the connecting tube portion 56. A fixing ring 57 formed in a C-shape is fitted radially into the groove portion 56A.

The fixing ring 57 is fitted toward the drive unit 4 in the recess 52A2 formed on the lower end surface of the bottom wall of the cylindrical guide portion 52A and opening to the second port 10D side. 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 side through 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 this 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 this cutout forms an opening that communicates with the inside of the tube of the connection tube portion 56.

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.

The compression spring 53 biases the valve body 3 in the axial direction L relative to the screw shaft 43. This 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. The upper end of the compression spring 53 abuts against the screw shaft side flange portion 51B, and the lower end of the compression spring 53 abuts against the valve body side flange portion 52B.

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 rotated 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 high refrigerant pressure 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. The above describes the valve open to valve closed states in this embodiment in order, but it goes without saying that the reverse operation from valve closed to valve open occurs 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.

When assembling this motor-operated valve 100, the lower end of the case member 11 is fitted into the upper end of the valve shell 10 as shown in Figure 2. Specifically, 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, while the case member 11 is fitted into 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 Figure 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 Figure 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) in 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 L of the contact portion between the ring-shaped portion 2B and the valve outer shell 10) is greater than the thickness a of the case member 11 and the 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 side. In this way, the heat generated at the first welded portion W1 is efficiently transferred to the ring-shaped portion 2B.

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 peripheral 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 welding the valve outer shell 10 and the case member 11 can be efficiently transferred to the ring-shaped portion 2B. This prevents the welding heat from remaining at the first welded portion W1, which would cause 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, etc. is thinned, it is possible to prevent stress corrosion cracking due to the influence of thermal stress.

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

In addition, in a specified range near the first welded portion W1, the cross-sectional area of the ring-shaped portion 2B can be made larger than the combined cross-sectional area of the valve outer shell 10 and the case member 11, so that heat generated around the first welded portion 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. This makes it possible to further suppress thermal stress generated around the welded portion.

In addition, the ring-shaped portion 2B can be press-fitted into the inner circumference of at least one of the valve outer shell 10 and the case member 11, so that 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 the heat generated around the first welded portion W1 can be efficiently transferred to the ring-shaped portion 2B.

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 portion W1 in the modified example. The motor-operated valve 100 in FIG. 4(A) is different from the motor-operated valve 100 of the present embodiment in that the ring-shaped portion 2B does not have a protrusion 2B2 formed thereon, and the upper portion of the outer peripheral surface 2B1 is welded to the inner peripheral surface of the cover member 10B to form the second welded portion W2.

The motor-operated valve 100 in FIG. 4(B) is different from the motor-operated valve 100 of this embodiment in that it does not have the protruding portion 2B2, as in FIG. 4(A). Also, the outer diameter dimension of the upper end of the cover member 10B is not smaller than the outer diameter dimension of the other parts of the cover member 10B, and the outer diameter dimension of the lower end of the case member 11 is smaller than the outer diameter dimension of the other parts of the case member 11. That is, the case member 11 side 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 this embodiment, so that the case member 11 guides the valve shell 10. The step portion 11B2 and the upper end surface 10B3 of the cover member 10B are welded to form the first welded portion W1. The inner circumferential surface of the case member 11 and the outer circumferential surface 2B1 of the ring-shaped portion 2B are welded to form the second welded portion W2. In this manner, the ring-shaped portion 2B is provided radially inside the first welded portion W1 between the cover member 10B (valve outer shell 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 outer shell 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 of the contact portion between the ring-shaped portion 2B and the case member 11 in the axial direction L) is greater than the thickness a and thickness b described above.

4(C), the motor-operated valve 100 does not have a guide surface 10B1 and a step portion 10B2, and the upper end surface 10B3 of the cover member 10B is welded to the lower end surface 11B of the case member 11 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 with the cover member 10B and 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 transferred directly or indirectly 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 FIG. 4(C), the second welded portion W2 is provided on the upper side of the outer peripheral surface 2B1 of the ring-shaped portion 2B, but the second welded portion W2 may be provided on the lower side of the outer peripheral surface 2B1.

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 the axial range of the axial height d on the outer peripheral surface 2B1 of the ring-shaped portion 2B, which is the 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 the axial range of the axial height d on the outer peripheral surface 2B1 of the ring-shaped portion 2B, which is the contact portion between the ring-shaped portion 2B and the case member 11. In the 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 the axial range of the axial height d on the outer circumferential surface 2B1 of the ring-shaped portion 2B, which is the 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 the welding heat can be transferred to the ring-shaped portion 2B more efficiently.

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 conduits as shown in the figure, constituting a heat pump type refrigeration cycle. Note that an accumulator, a pressure sensor, a temperature sensor, etc. are omitted from the illustration.

The flow path of the refrigeration cycle is switched by the flow path switching valve 4000 to two different flow paths: one for cooling operation and one for heating operation. During cooling operation, as shown by the solid arrows in Figure 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.

On the other hand, during heating operation, as shown by the dashed arrows in Figure 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 that flows in from the outdoor heat exchanger 2000 side during cooling operation, or the liquid refrigerant that flows in from the indoor heat exchanger 3000 side during heating, and further controls the flow rate of the refrigerant.

With this configuration, a refrigeration cycle system can be constructed using an electric valve 100 that can prevent stress corrosion cracking due to thermal stress even when the case member 11, etc., is thin-walled.

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 lid member 10B, but the valve body 10A and the lid member 10B do not necessarily need to be provided separately, and they may be provided integrally, or the lid member 10B may be omitted.

In this embodiment, the drive unit 4 is a screw feed mechanism formed by 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 within 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 around 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 rather than 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 within the valve housing 1. In addition, the valve device of the present invention can be applied to various valve devices such as solenoid valves and temperature-controlled expansion valves in addition to the motor-operated valve 100 of the above embodiment and modified example.

The above describes the embodiments of the present invention in detail with reference to the drawings, but the specific configuration is not limited to these embodiments, and the present invention also includes design changes that do not deviate from the gist of the present invention.

S Valve chamber W1 First welded part (welded part)
2B Ring-shaped portion (ring-shaped member)
10 Valve shell 11 Case member 100 Motor-operated valve (valve device)

Claims (7)

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. 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. The valve device according to claim 2, characterized in that in a predetermined area near the welded portion, the cross-sectional area of the ring-shaped member is greater than the combined cross-sectional area of the valve shell and the case member. The valve device according to any one of claims 1 to 3, characterized in that the ring-shaped member is press-fitted into the inner circumference of at least one of the valve outer shell and the case member. 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. 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. A refrigeration cycle system including a compressor, an expansion valve, and an evaporator, characterized in that the valve device according to any one of claims 1 to 4 or the motor-operated valve according to claims 5 or 6 is used as the expansion valve.

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