Valve mechanism

Abstract

To provide a valve device which can prevent the leakage of a working fluid through a valve seat part even if the valve seat part possesses a material defect such as a nest.SOLUTION: A valve device 100 comprises a valve seat part 20A composed of a push-out rod or a withdrawal rod, and having a pair of axial-direction cut faces 21, 22 formed by cutting processing. In a pair of overlap regions 21j, 22j in which the one-side axial-direction cut face 21 and the other-side axial-direction cut face 22 are overlapped on each other when viewing the valve seat part 20A from an axial line direction L, working fluid leakage prevention means 81A, 2 are arranged at least at the former of the one-side overlap reverse 21j and the other-side overlap region 22j so that a working fluid is not leaked due to the imposition of a pressure difference in the inside and the outside of a fluid path in the axial line direction L, and regions Rs1, Rp1 in which the working fluid leakage prevention means 81A, 2 are arranged are arranged all over the pair of overlap regions 21j, 22j when viewed from the axial line direction L.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a valve assembly comprising a push rod or a pull rod and a valve seat having a pair of axially cut surfaces formed by machining. [Background technology]

[0002] The material used for the valve seat of the valve gear is sometimes a steel material made by adding a small amount of alloying elements (additives) to metal materials such as brass and stainless steel in order to improve machinability during processing. These alloying elements are difficult to form into an alloy when manufacturing the steel material, and may remain in the metal material as tiny cavities, which are material defects such as voids.

[0003] In the subsequent process of forming a bar by extrusion or drawing, minute cavities are formed in the metal material so as to extend in the axial direction of the bar. In the subsequent process of forming a pair of axial cut surfaces in the bar by cutting, there is a risk that the minute cavities extending in the axial direction (hereinafter referred to as "axial cavities") may be exposed to the outside from each axial cut surface.

[0004] For example, Patent Document 1 (see FIG. 1 in particular) describes a valve device that includes a valve seat member 11 that is joined to a fitting hole provided at one axial end of a valve body 10, and a second inlet / outlet 7 that is made of a coupling pipe that is joined to the valve seat member 11. Patent Document 1 does not describe the processing steps for forming the valve seat member 11, but since the valve seat member 11 shown in FIG. 1 has sharp corners, it is assumed here that the valve seat member 11 is made of a push-out rod or pull-out rod, has a pair of axial cut surfaces formed by cutting, and has a minute cavity extending in the axial direction inside.

[0005] In this valve seat member 11, a pair of axially cut surfaces include an inner exposed surface and an outer exposed surface that are exposed to the inner space (valve chamber 12) and the outer space, respectively, and the inner exposed surface and the outer exposed surface are arranged to overlap when viewed from the axial direction. Furthermore, an axial cavity is interposed between the overlapping regions of the inner exposed surface and the outer exposed surface. Therefore, particularly when the working fluid is not a liquid but a gas or a gas-liquid two-phase flow, if a differential pressure between the inside and outside of the fluid path is applied in the axial direction of the valve seat member 11, there is a problem that, in the worst case, leakage of the working fluid occurs through the overlapping regions of the inner exposed surface and the outer exposed surface and the axial cavity (hereinafter referred to as "conventional problem (leakage of working fluid through the axial cavity)"). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-156447 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a valve device that can prevent leakage of a working fluid through a valve seat portion even if the valve seat portion has a material defect such as a void. [Means for solving the problem]

[0008] In order to solve the above problems, the valve device comprises a valve body formed from a thin plate and constituting an internal space, a valve seat portion made of a push rod or a pull rod and having a pair of axially cut surfaces formed by cutting, and a valve port penetrating between the pair of axially cut surfaces, the valve seat portion being joined from one axial end side to a fitting hole provided at one axial end of the valve body, and a valve body for changing the opening degree of the valve port, wherein when the valve seat portion is viewed from the axial direction, regions where the axially cut surface on one side and the axially cut surface on the other side overlap each other are defined as a pair of overlapping regions, and in the pair of overlapping regions, at least a part of a working fluid leakage prevention means is provided in at least the former of the one-side overlapping region and the other-side overlapping region so that a differential pressure between the inside and outside of a fluid path is applied in the axial direction to prevent leakage of the working fluid, and the region in which the working fluid leakage prevention means is provided is provided over the entirety of the pair of overlapping regions as viewed from the axial direction.

[0009] In addition, in the above-mentioned valve device, the working fluid leakage prevention means may include an axial sealing portion, and by joining a joint portion of a connecting pipe to the valve seat portion, the pair of overlapping regions may be defined as a pair of inner overlapping regions and a pair of outer overlapping regions located radially inward and radially outward from the joint portion, one of the inner overlapping regions may be disposed in an internal region of the connecting pipe, and the axial sealing portion may be provided in one of the pair of outer overlapping regions.

[0010] In the above valve device, the axial sealing portion may be formed by adhering a molten and solidified brazing material.

[0011] Moreover, in the above valve device, the brazing material in the axial sealing portion may be accommodated in a recess formed so as to cover the entirety of either one of the pair of outer overlapping regions.

[0012] In the above valve device, the axial sealing portion may be formed by welding.

[0013] In the above valve device, the axial sealing portion may be formed by applying plastic working.

[0014] In the above valve device, the working fluid leakage prevention means may further comprise a circumferential sealing portion formed by adhering molten and solidified brazing material to a cylindrical region along a side surface of the valve seat portion when joining the valve seat portion to the valve body.

[0015] Moreover, in the above valve device, the working fluid leakage prevention means may be configured to set the outer diameter of the joint portion of the joint pipe larger than the inner diameter of the fitting hole of the valve body, and to position the entire overlapping region on one side within the internal region of the joint pipe by joining the joint portion of the joint pipe to the valve seat portion.

[0016] In the above valve device, the joint portion of the coupling pipe may be inserted into and joined to an insertion hole of the valve seat portion.

[0017] In the above valve device, an insertion tube of the valve seat may be inserted into and joined to the joint portion of the coupling pipe.

[0018] In the above valve device, the joint pipe may include a base portion and the joining portion having an inner diameter larger than an inner diameter of the base portion. Effect of the Invention

[0019] According to the present invention, it is possible to provide a valve device that can prevent leakage of working fluid through a valve seat portion even if the valve seat portion has a material defect such as a void. [Brief description of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view showing a valve device according to a first embodiment of the present invention in a valve closed state. [Diagram 2]2A and 2B are enlarged views showing the valve seat portion in FIG. 1, where (a) is an enlarged cross-sectional view of the valve seat portion, (b) is an enlarged view of a portion surrounded by dashed line IIb in (a), and (c) is an enlarged view of a portion surrounded by dashed line IIc in (a). [Diagram 3] 3 is an enlarged perspective view showing the valve seat portion in FIG. 2, where (a) is an upper perspective cross-sectional view showing the valve seat portion, the valve body, and each joint pipe, (b) is an upper perspective view showing the valve seat portion and the joint pipe, (c) is a lower perspective cross-sectional view showing the valve seat portion, the valve body, and each joint pipe, and (d) is a lower perspective view showing the valve seat portion and the joint pipe. [Figure 4] FIG. 6 is an enlarged view showing a valve seat portion in a valve device according to a second embodiment. [Diagram 5] FIG. 11 is an enlarged view showing a valve seat portion in a valve device according to a third embodiment. [Figure 6] FIG. 10 is an enlarged view showing a valve seat portion in a valve device according to a fourth embodiment. [Figure 7] FIG. 13 is an enlarged view showing a valve seat portion in a valve device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An embodiment of the present invention will be described in detail with reference to Figures 1 to 7. Note that, although a valve gear will be described below, a valve seat portion of the valve gear of the present invention can be applied as a valve seat portion in a motor-operated valve, a mechanical expansion valve, a manual on-off valve, and a solenoid valve.

[0022] <Terminology> In the present specification and claims, the terms "left", "right", "upper" and "lower" refer to the directions shown in Figs. 1 to 7. In the present specification and claims, the terms "one end" and "other end" refer to the "lower end in the axial direction" and the "upper end in the axial direction", respectively. In the present specification and claims, the terms "one side" and "other side" refer to the "lower side in the axial direction" and the "upper side in the axial direction". In the present specification and claims, the term "extruded bar" refers to a bar material formed by extrusion. In the present specification and claims, the term "drawn bar" refers to a bar material formed by drawing. In the present specification and claims, the term "draft slope" refers to a slope provided to tilt the side of the forged product with respect to the forging direction in order to facilitate the material flow in die forging and the removal of the forged product from the die immediately after stamping. In the present specification and claims, a "pair of axially cut surfaces" refers to cut surfaces facing the axial direction on one side and the other side formed by cutting. In the present specification and claims, a "pair of overlapping regions" refers to regions where an axially cut surface on one side overlaps an axially cut surface on the other side when the valve seat portion is viewed from the axial direction. In the present specification and claims, a "pair of inner overlapping regions" and a "pair of outer overlapping regions" refer to regions radially inward and outward from the joint of the coupling pipe in a pair of overlapping regions.

[0023] (First embodiment) <Valve gear configuration> A valve device 100 according to a first embodiment of the present invention will be described with reference to Fig. 1. The valve device 100 is mainly composed of a valve body 10, a valve seat portion 20 (20A), a support member 30, a drive shaft 40, a valve body portion 50, a stepping motor 60, and a rotation stopper mechanism 70. Each component of the valve device 100 will be described below in order.

[0024] Here, the valve gear 100 of the first to third embodiments employs a working fluid leakage prevention means in the valve seat portion 20A, 20B, 20C, as will be described in detail later. The working fluid leakage prevention means is such that the inner overlapping area 21ja (see FIG. 2(a)) on one side of the valve seat portion 20A, 20B, 20C is disposed in the inner area Rp1 (see FIG. 2(b)) of the second joint pipe 2, and the axial direction hole sealing portion 81A, 81B, 81C is provided in one of the pair of outer overlapping areas 21jb, 22jb (FIGS. 2, 4, and 5). The working fluid leakage prevention means employed in the valve seat portion 20 in the valve gear 100 of the fourth and fifth embodiments is such that the overlapping area 121j, 221j on one side of the valve seat portion 120, 220 is disposed in the inner area Rp2 of the second joint pipe 2. This makes it possible to eliminate the conventional problem (leakage of the working fluid through the axial cavity) even if the valve seat portion 20 has a material defect such as a porosity. In this embodiment, the axial hole sealing portions 81A, 81B, 81C are provided in one of the pair of outer overlapping regions 21jb, 22jb, but it is preferable to provide the axial hole sealing portions 81A, 81B, 81C in the other outer overlapping region 22jb, which is the inlet side of the leakage path of the working fluid, rather than providing them in the outer overlapping region 21jb on one side, which is the outlet side of the leakage path of the working fluid, because this can more effectively prevent leakage of the working fluid.

[0025] The valve body 10 is formed into a cylindrical shape by press molding of a thin plate made of a metal such as stainless steel. A fitting hole 10a is provided in the lower part of the valve body 10, and a valve seat portion 20 formed separately from the valve body 10 is attached to close the fitting hole 10a. A first joint pipe 1 is connected to the outer peripheral side wall of the valve body 10 as a flow path for a fluid such as a refrigerant. The first joint pipe 1 is connected to a valve chamber 11 formed in the internal space of the valve body 10. The first joint pipe 1 is formed into a cylindrical shape by press molding of a thin plate made of a material such as copper or stainless steel, and is fixed to the valve body 10 by brazing with a brazing material r or the like.

[0026] The valve seat 20 is made of an extruded rod or drawn rod, which is a rod material produced by a manufacturing process such as extrusion or drawing, and a valve port 20a is opened in the center of the valve seat 20 along the axis L. An insertion hole 23 to which the second coupling pipe 2 is connected is provided in the lower end surface of the valve port 20a, and the second coupling pipe 2 communicates with the valve chest 11 via the valve port 20a. The second coupling pipe 2 is made of a material such as copper or stainless steel, and is formed into a cylindrical shape by press molding or the like from a thin plate, and is fixed to the valve seat 20 by brazing or the like.

[0027] The support member 30 includes a substantially cylindrical holder portion 31 made of a resin material such as polyphenylene sulfide (PPS), and a stainless steel fixing portion 32 that is integrally provided by insert molding on an end portion of the holder portion 31 that is closer to the valve body 10. The support member 30 is fixed to the valve body 10 by the fixing portion 32 through welding.

[0028] The holder part 31 is disposed so that its axis overlaps with the axis L passing through the axis of the valve port 20a. A screw hole 33 and a slide hole 35 are formed concentrically in the center of the holder part 31, aligned in the direction of the axis L so as to penetrate the holder part 31. A female screw portion 33a is formed on the inner peripheral surface of the screw hole 33, into which a male screw portion 41a of a drive shaft 40 described later is screwed. The slide hole 35 is disposed closer to the valve port 20a, and is formed with a larger diameter than the screw hole 33. A valve body part 50 described later is slidably engaged with the slide hole 35.

[0029] The drive shaft 40 is formed into a cylindrical rod shape using a metal such as stainless steel. The drive shaft 40 is formed with a threaded portion 41 aligned in the direction of the axis L, and a flange portion 43 disposed at the end of the threaded portion 41 closer to the valve port 20a. The threaded portion 41 is formed with a male threaded portion 41a, which is screwed into a female threaded portion 33a of the holder portion 31, whereby the rotational motion of the drive shaft 40 is converted into linear motion in the direction of the axis L by a screw feed action. The flange portion 43 rotatably holds a valve body portion 50, which will be described later.

[0030] The valve body portion 50 includes a valve holder 51 , a valve body 52 , a washer 53 , a spring receiver 54 , and a compression coil spring 55 .

[0031] The valve holder 51 is formed in a cylindrical shape with an outer diameter substantially the same as the inner diameter of the slide hole 35 of the holder portion 31. The valve holder 51 is engaged along the slide hole 35 so as to be slidable in the axial L direction.

[0032] The valve element 52 is needle-shaped and is fixed to the lower end 51a of the valve holder 51 on the valve port 20a side so that the tip of the needle faces the valve port 20a. The valve element 52 adjusts the flow rate by adjusting the opening between the valve port 20a and the valve seat between the maximum valve opening and the minimum valve opening (or fully closed state).

[0033] The flange portion 43 of the drive shaft 40 is rotatably hooked to the upper end portion 51b of the valve holder 51 on the side opposite to the valve port 20a side. Specifically, a washer 53 is sandwiched between the flange portion 43 of the drive shaft 40 and the upper end portion 51b of the valve holder 51, and the drive shaft 40 is rotatably hooked to the upper end portion 51b of the valve holder 51 by this flange portion 43. Due to this engagement, the valve holder 51 is supported by the drive shaft 40 so as to be movable in the axis L direction and to be rotatable about the axis L. An opening larger than the radial movable range of the drive shaft 40 is formed in the upper end portion 51b of the valve holder 51. In addition, a spring receiver 54 is provided in the valve holder 51 so as to be movable in the axis L direction. A compression coil spring 55 is attached between the spring receiver 54 and the valve body 52 in a compressed state with a predetermined load applied. As a result, the spring receiver 54 is pressed against the drive shaft 40 and comes into contact with the flange portion 43 of the drive shaft 40 .

[0034] The stepping motor 60 includes a case 61 , a magnet rotor 62 , and a stator coil 63 .

[0035] The case 61 is made of a metal such as stainless steel and formed into a generally cylindrical shape with the upper end closed by press molding of a thin plate. The lower open end of the case 61 is airtightly fixed to the upper end of the valve body 10 by welding or the like.

[0036] The magnet rotor 62 integrally comprises a cylindrical magnet portion 64 whose outer periphery is magnetized with multiple poles, and a disk portion 65 closing one end of the magnet portion 64. The magnet rotor 62 is fixed to the drive shaft 40 via a metal fitting 66 integrally formed in the center of the disk portion 65. As a result, the magnet rotor 62 is provided in the case 61 so as to be rotatable about the axis L of the drive shaft 40. The drive shaft 40 is the rotation axis of the magnet rotor 62. In addition, the magnet rotor 62 is formed with a protrusion 67.

[0037] The stator coil 63 is disposed on the outer circumferential surface of the case 61, and when a pulse signal is given to the stator coil 63, the magnet rotor 62 is rotated according to the number of pulses.

[0038] The rotation stopper mechanism 70 is provided so as to hang down from the inner ceiling of the case 61, and includes a cylindrical portion 71 having a cylindrical shape, a guide member 72 arranged inside the cylindrical portion 71, having a cylindrical shape, and guiding the upper end of the drive shaft 40, a spiral guide wire body 73 fixed to the outer periphery of the cylindrical portion 71, and a movable slider 74 that can rotate and move up and down while being guided by the guide wire body 73. As the magnet rotor 62 rotates, the protrusions 67 of the magnet rotor 62 operate the rotation stopper mechanism 70, and the lowermost and uppermost positions of the drive shaft 40 (and the magnet rotor 62) are restricted. Thus, the valve body 50 is restricted from moving beyond the position where the valve body 50 is at the maximum opening degree or the position where the valve body 50 is at the minimum opening degree (or the valve is closed).

[0039] <Valve mechanism operation> In the valve device 100, when the stepping motor 60 is driven, the magnet rotor 62 and the drive shaft 40 rotate, and the drive shaft 40 advances and retreats in the direction of the axis L due to a screw feed mechanism consisting of the male thread portion 41a and the female thread portion 33a. The advancement and retreat of the drive shaft 40 accompanying this rotation causes the valve body 52 to advance and retreat in the direction of the axis L together with the valve holder 51. The valve body 52 changes the opening area of ​​the valve port 20a, i.e., the opening degree, by the advancement and retreat of its tip in the direction of the axis L. Thus, the flow rate of the fluid flowing from the first joint pipe 1 to the second joint pipe 2 (or from the second joint pipe 2 to the first joint pipe 1) is controlled.

[0040] <Valve seat details> The valve seat portion 20A will be described in detail with reference to Figures 2 and 3. In Figures 2 and 3, the support member 30 and the valve body portion 50 are omitted from the illustration in order to mainly describe the valve seat portion 20A. The material of the valve seat portion 20A is an extruded rod or a drawn rod, which is a rod material formed by an extrusion process or a drawing process. The valve seat portion 20A also includes a pair of axial cut surfaces 21, 22 formed by a cutting process, and a valve port 20a penetrating between the pair of axial cut surfaces 21, 22 in the axis L direction.

[0041] Generally, it is known that the valve seat has a corner on the outer periphery and a straight part of the same diameter, while the valve seat made of a forged product has a large R part and a draft slope on the outer periphery, which is different in appearance. Note that the valve seat made of a forged product having a large R part and a draft slope on the outer periphery does not have a minute cavity extending in the axial direction L due to the difference in the manufacturing method of the material, so the possibility of the working fluid leaking to the outside is extremely low. Similarly, the valve body 10, the first joint pipe 1, the second joint pipe 2, and the case 61 formed by press molding or the like from a thin plate do not have a minute cavity extending in the axial direction L due to the difference in the manufacturing method of the material, so the possibility of the working fluid leaking to the outside is extremely low.

[0042] As described above in the Background Art section, the inside of the valve seat portion 20A made of a push rod or a pull rod may have an axial cavity P, which is a material defect such as a porosity. Therefore, in the following description, it is assumed that the axial cavity P is formed inside the valve seat portion 20A.

[0043] In the pair of axially cut surfaces 21, 22, the axial cavity P is exposed to the outside from each of the axially cut surfaces 21, 22, respectively.

[0044] <About a pair of overlapping regions> When the valve seat 20A is loaded with a pressure difference between inside and outside the fluid path in the axial L direction, the working fluid may leak into the external space through the axial cavity P. Specifically, when the other axial cut surface 22 is exposed to the pressure in the valve chamber 11 and the one axial cut surface 21 is exposed to atmospheric pressure outside the fluid path, the working fluid enters the valve seat 20A from the other axial cut surface 22 where the axial cavity P is exposed. At this time, since the axial cavity P extends in the axial L direction, the working fluid mainly moves in the axial L direction and leaks out. In this way, when considering the leakage of the working fluid through the valve seat 20A, a pair of overlapping regions 21j, 22j, where the one axial cut surface 21 and the other axial cut surface 22 overlap when the valve seat 20A is viewed from the axial L direction, can be taken into consideration to provide a clear and concise explanation.

[0045] <Means for preventing working fluid leakage> In order to prevent leakage of the working fluid through the valve seat portion 20A, a working fluid leakage prevention means must be provided in at least one of the overlapping region 21j on one side and the overlapping region 22j on the other side, and when viewed from the direction of the axis L, the area in which the working fluid leakage prevention means is provided must extend over the entire pair of overlapping overlapping regions 21j, 22j.

[0046] 2(a), 3(a) and 3(c), the joint portion 2a of the second joint pipe 2 is joined to the insertion hole 23 of the valve seat portion 20A. Here, the joint portion 2a of the joint pipe 2 is used to define the pair of overlapping regions 21j, 22j into a pair of inner overlapping regions 21ja, 22ja (white regions in FIG. 3) located radially inside the joint portion 2a, and a pair of outer overlapping regions 21jb, 22jb (hatched regions in FIG. 3) located radially outside the joint portion 2a.

[0047] <Means for preventing working fluid leakage (inner overlapping area)> As described above, the joint portion 2a of the second joint pipe 2 is joined to the insertion hole 23 of the valve seat portion 20A. Therefore, the means for preventing leakage of the working fluid in the pair of inner overlapping regions 21ja, 22ja is to dispose the inner overlapping region 21ja on one side in the internal region Rp1 (see FIG. 2(b)) of the second joint pipe 2. As a result, even if the working fluid moves in the direction of arrow A in FIG. 2(a) from the inner overlapping region 22ja on the other side through the axial cavity P to the inner overlapping region 21ja on one side, the working fluid is located in the internal region Rp1 of the second joint pipe 2 and therefore does not leak into the external space outside the fluid path.

[0048] <Means for preventing working fluid leakage (outer overlapping area)> 2(b) and 3(c), the working fluid leakage prevention means in the pair of outer overlapping regions 21jb, 22jb is to provide an axial hole sealing portion 81A so as to cover the entire outer overlapping region 21jb on one side. This axial hole sealing portion 81A is composed of a recess 81c formed in an annular shape so as to cover the entire outer overlapping region 21jb on one side, and a molten and solidified brazing material 81r accommodated in this recess 81c.

[0049] In this way, the axial sealing portion 81A can melt the brazing material 81r itself by brazing, and spread it so as to cover the entire outer overlapping region 21jb on one side with the brazing material 81r having a desired thickness. This allows the axial cavity P to be reliably sealed to a desired thickness in the outer overlapping region 21jb on one side. Therefore, even if the working fluid moves in the direction of arrow A in FIG. 2(a) from the outer overlapping region 22jb on the other side through the axial cavity P to the outer overlapping region 21jb on one side, the path of this working fluid is blocked by the sealing region Rs1 (see FIG. 2(b)) to which the axial sealing portion 81A is applied, and therefore the working fluid does not leak into the external space outside the fluid path.

[0050] In this embodiment, the melted brazing material 81r is accommodated in the recess 81c, so that the outer diameter of the sealing region Rs1 where the axial sealing portion 81A is applied can be set by the outer diameter of the recess 81c with respect to the outer overlapping region 22jb on the other side. This makes it easy to manage the position of the sealing region Rs1. In this embodiment, the axial sealing portion 81A is composed of the recess 81c and the molten and solidified brazing material 81r accommodated in the recess 81c, but this is not limited thereto. For example, the recess 81c may be omitted, and the brazing material 81r may be attached so as to cover the entire outer overlapping region 21jb on one side. In this embodiment, the axial sealing portion 81A is provided so as to cover the entire outer overlapping region 21jb on one side. However, this is not limited to the above, and for example, the axial sealing portion 81A may be provided so as to cover the entire other outer overlapping region 22jb, or may be provided in both the one side outer overlapping region 21jb and the other side outer overlapping region 22jb, and when viewed from the axial L direction, the area in which the axial sealing portion 81A is provided may be provided over the entire pair of overlapping outer overlapping regions 21jb, 22jb.

[0051] <Means for preventing working fluid leakage (cylindrical area)> 2(c), the valve seat portion 20A includes an inner side wall 24a inserted into the fitting hole 10a, an outer side wall 24b exposed to the external space, and a mounting step portion 24c located between the inner side wall 24a and the outer side wall 24b and engaging with the fitting hole 10a. When the inner side wall 24a is formed by, for example, a cutting process, a part of the axial cavity P located near the surface of the inner side wall 24a may be opened by the cutting process to form a minute opening exposed on the surface of the inner side wall 24a, which may communicate with the outer overlap region 21jb on one side.

[0052] Specifically, the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 24a, and then moves in the direction of arrow A in FIG. 2(a) to the outer overlapping region 21jb on one side. Here, as shown in FIG. 2(a), if the axial sealing portion 81A is provided so as to cover the entire outer overlapping region 21jb on one side, leakage of the working fluid can be prevented. However, for example, if the axial sealing portion 81A is provided so as to cover the entire outer overlapping region 22jb on the other side and is not provided in the outer overlapping region 21jb on one side, there is a risk that the working fluid may leak, although slightly, into the external space outside the fluid path through the valve seat portion 20A (inner side wall 24a → axial cavity P → outer overlapping region 21jb on one side).

[0053] In response to this, the working fluid leakage prevention means, as shown in FIG. 2(c), further comprises providing a circumferential sealing portion 82 (see FIGS. 3(a) to 3(c)) formed by adhering molten and solidified brazing material 82r to a cylindrical region (hatched region in the figure) along the side of the valve seat portion 20A when joining the valve seat portion 20A to the fitting hole 10a of the valve body 10.

[0054] Specifically, as shown in Fig. 2(c), the inner side wall 24a having an outer diameter slightly smaller than the inner diameter of the fitting hole 10a is inserted into the fitting hole 10a of the valve body 10, and the mounting step 24c, which is the side wall of the valve seat 20A, is joined to the fitting hole 10a of the valve body 10 with a brazing material 82r. This brazing material 82r permeates into the mounting step 24c of the valve seat 20A and the fine openings formed on the surface of the inner side wall 24a, and then flows into the axial cavity P communicating with the openings, and closes the axial cavity P. As a result, as shown in Figs. 3(a) to 3(c), a sealing treatment can be performed on the inner side wall 24a of the valve seat 20A as the circumferential sealing portion 82, which has a slight depth in the radial direction and forms a cylindrical region.

[0055] Therefore, even if the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 24a and then moves in the direction of arrow A in Figure 2(a) near the inner side wall 24a of the valve seat portion 20A, the working fluid will not leak into the external space outside the fluid path because its path will be blocked by the sealing region Rs1' (see Figure 2(c)) where the circumferential sealing portion 82 is provided.

[0056] In the present embodiment, the working fluid leakage prevention means is arranged such that the inner overlap region 21ja on one side is disposed in the internal region Rp1 (see FIG. 2(b)) of the second joint pipe 2, and the sealing region Rs1 with the axial sealing portion 81A is provided so as to cover the entire outer overlap region 21jb on one side. As a result, the regions Rp1, Rs1 in which the working fluid leakage prevention means is provided are provided over the entire pair of overlapping regions 21j, 22j when viewed from the axis L direction. In this way, by providing the working fluid leakage prevention means so as to cover the entire outer overlap region 21jb on one side, the conventional problem (leakage of the working fluid through the axial cavity) can be eliminated even if the valve seat portion 20A has a material defect such as a porosity. In addition, the working fluid leakage prevention means in the present embodiment employs the internal region Rp1 of the second joint pipe 2, and can reliably prevent leakage of the working fluid in the pair of inner overlap regions 21ja, 22ja without increasing the number of parts, etc. Furthermore, the working fluid leakage prevention means in this embodiment provides a sealing region Rs1' in which a circumferential sealing portion 82 is applied to the inner side wall 24a of the valve seat portion 20A.In addition to the sealing region Rs1 in the outer overlap region 21jb on one side, a sealing region Rs1' is provided between the pair of outer overlap regions 21jb, 22jb, thereby more reliably preventing leakage of the working fluid.

[0057] <About the valve seat assembly process> In the assembly process of the valve seat portion 20A, when the axial sealing portion 81A is provided in the outer overlapping region 21jb on one side as shown in FIG. 2(b), first, as shown in FIG. 2(c), the mounting step portion 24c of the valve seat portion 20A is brazed to the fitting hole 10a of the valve body 10. This provides a circumferential sealing portion 82 that is a cylindrical region. Next, the first joint pipe 1 is brazed to the valve body 10, and at the same time, the joint portion 2a of the second joint pipe 2, which has an outer diameter slightly smaller than the inner diameter of the insertion hole 23, is brazed to the insertion hole 23 of the valve seat portion 20A to define the inner region Rp1 (see FIG. 2(b)) of the second joint pipe 2. Here, when the second joint pipe 2 is brazed to the insertion hole 23 of the valve seat portion 20A, a brazing material is poured into the recess 81c of the valve seat portion 20A. As a result, an axial sealing portion 81A is provided in the outer overlap region 21jb on one side.

[0058] In this embodiment, the step of providing the axial sealing portion 81A can be performed simultaneously with other steps, so that the assembly step can be prevented from becoming complicated.

[0059] On the other hand, when the axial sealing portion 81A is provided in the outer overlapping region 22jb on the other side, a brazing material made of a ring brazing material is first set in an annular recess (not shown) formed in the outer overlapping region 22jb on the other side, and the mounting step portion 24c of the valve seat portion 20A is brazed to the fitting hole 10a of the valve body 10, and at the same time, the brazing material is poured into the recess of the valve seat portion 20A. As a result, a circumferential sealing portion 82 that becomes a cylindrical region is provided, and the axial sealing portion 81A is provided in the outer overlapping region 22jb on the other side. Next, the first joint pipe 1 is brazed to the valve body 10, and at the same time, the second joint pipe 2 is brazed to the insertion hole 23 of the valve seat portion 20A to define the inner region Rp1 of the second joint pipe 2.

[0060] In this embodiment, the step of providing the axial sealing portion 81A can be performed simultaneously with other steps, so that the assembly step can be prevented from becoming complicated.

[0061] Second embodiment Here, the valve seat portion 20B according to the second embodiment will be described with reference to Fig. 4. The valve seat portion 20B in the second embodiment differs from the valve seat portion 20A in the first embodiment in the axial direction hole sealing portion 81B provided in the outer overlapping region 22jb on the other side, but the other basic configuration is the same as that of the first embodiment. Here, the same members are given the same reference numerals, and duplicated explanations (<Regarding the working fluid leakage prevention means (inner overlapping region)> and <Regarding the working fluid leakage prevention means (cylindrical region)>) are omitted, and only <Regarding the working fluid leakage prevention means (outer overlapping region)> and <Regarding the assembly process of the valve seat portion> will be described.

[0062] <Means for preventing working fluid leakage (outer overlapping area)> 4, the working fluid leakage prevention means for the pair of outer overlapping regions 21jb, 22jb is to provide an axial hole sealing portion 81B so as to cover the entire outer overlapping region 22jb on the other side. This axial hole sealing portion 81B is made of a welded portion 81w provided by welding so as to cover the entire outer overlapping region 22jb on the other side.

[0063] In this way, the axial sealing portion 81B melts the base material, that is, the other-side outer overlapping region 22jb itself, by welding. This allows the axial cavity P to be exposed in the other-side outer overlapping region 22jb to be reliably sealed, including the melting depth. Therefore, even if the working fluid attempts to enter the axial cavity P through the other-side outer overlapping region 22jb in the direction of arrow A in FIG. 4, the path of the working fluid is blocked by the sealing region Rs2 to which the axial sealing portion 81B is applied, and as a result, the working fluid does not leak into the external space outside the fluid path.

[0064] In this embodiment, the axial hole sealing portion 81B is provided so as to cover the entire outer overlapping region 22jb on the other side. However, this is not limited thereto, and for example, the axial hole sealing portion 81B may be provided so as to cover the entire outer overlapping region 21jb on one side, or may be provided in both the outer overlapping region 21jb on one side and the outer overlapping region 22jb on the other side, and the region in which the axial hole sealing portion 81B is provided may be provided over the entire pair of overlapping outer overlapping regions 21jb, 22jb as viewed from the axis L direction. Furthermore, in this embodiment, from the viewpoint of aesthetics, it is preferable that the welded portion 81w, which is the axial hole sealing portion 81B, is provided in the outer overlapping region 22jb on the other side, which is not visible to the human eye, rather than in the outer overlapping region 21jb on the one side, which is visible to the human eye. Furthermore, in this embodiment, since it is difficult to perform the hole sealing treatment by welding over a wide area at once, it is preferable to apply it when the width of the pair of outer overlapping regions 21jb, 22jb is relatively narrow.

[0065] In this way, the second embodiment also has the same effect as the first embodiment, that is, by providing the working fluid leakage prevention means so as to cover the entire outer overlap region 22jb on the other side, the conventional problem (leakage of the working fluid through the axial cavity) can be eliminated even if the valve seat portion 20B has a material defect such as a porosity. Also, in the second embodiment, the working fluid leakage prevention means employs the inner region Rp1 of the second joint pipe 2 as the working fluid leakage prevention means, so that leakage of the working fluid in the pair of inner overlap regions 21ja, 22ja can be reliably prevented without increasing the number of parts, etc. In addition, in the second embodiment, a sealing region Rs1' (see Figure 2(c)) in which a circumferential sealing portion 82 is provided on the inner side wall 24a of the valve seat portion 20B is provided. Therefore, even if the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 24a and then moves in the direction of arrow A near the inner side wall 24a of the valve seat portion 20B, the working fluid will not leak into the external space outside the fluid path because its path is blocked by the sealing region Rs1' in which the circumferential sealing portion 82 is provided.

[0066] <About the valve seat assembly process> In the assembly process of the valve seat portion 20B, when the axial sealing portion 81B is provided in the outer overlapping region 22jb on the other side as shown in FIG. 4, first, welding is performed on the outer overlapping region 22jb on the other side of the valve seat portion 20B to provide the axial sealing portion 81B. Next, the mounting step portion 24c of the valve seat portion 20A is brazed to the fitting hole 10a of the valve body 10. This provides a circumferential sealing portion 82 that becomes a cylindrical region. Furthermore, the first joint pipe 1 is brazed to the valve body 10, and at the same time, the second joint pipe 2 is brazed to the insertion hole 23 of the valve seat portion 20A to define the internal region Rp1 of the second joint pipe 2.

[0067] In this embodiment, since the process of providing the axial sealing portion 81B can be added simply before the conventional assembly process, the assembly process can be prevented from becoming complicated.

[0068] On the other hand, when the axial sealing portion 81B is provided in the outer overlapping region 21jb on one side, the mounting step portion 24c of the valve seat portion 20B is first brazed to the fitting hole 10a of the valve body 10. This provides a circumferential sealing portion 82 that is a cylindrical region. Next, after the second coupling pipe 2 is inserted into the insertion hole 23 of the valve seat portion 20A, welding is performed on the outer overlapping region 21jb on one side to provide the axial sealing portion 81B. At this time, the insertion hole 23 into which the second coupling pipe 2 is inserted is slightly distorted by welding, so that the second coupling pipe 2 can be temporarily fixed. Furthermore, the first coupling pipe 1 is brazed to the valve body 10, and at the same time, the second coupling pipe 2 is brazed to the insertion hole 23 of the valve seat portion 20A.

[0069] In this embodiment, the process of providing the axial hole sealing portion 81B can be added to the replaced assembly process by slightly changing the order of the previous assembly process, so that the assembly process can be prevented from becoming complicated. When the valve seat portion 20B and the second joint pipe 2 are made of stainless steel, the second joint pipe 2 can be joined to the valve seat portion 20B and the outer overlap region 21jb on one side can be welded at the same time, so that the process of providing the axial hole sealing portion 81B can be performed simultaneously with other processes, so that the assembly process can be prevented from becoming complicated.

[0070] (Third embodiment) Here, a valve seat portion 20C according to a third embodiment will be described with reference to Fig. 5. The valve seat portion 20C in this third embodiment differs from the valve seat portion 20B in the second embodiment in that an axial direction hole sealing portion 81C provided in the outer overlapping region 22jb on the other side is different from that in the second embodiment, but the other basic configuration is the same as that in the second embodiment. Here, the same members are given the same reference numerals, and duplicated explanations (<Regarding the working fluid leakage prevention means (inner overlapping region)> and <Regarding the working fluid leakage prevention means (cylindrical region)>) are omitted, and only <Regarding the working fluid leakage prevention means (outer overlapping region)> and <Regarding the assembly process of the valve seat portion> will be described.

[0071] <Means for preventing working fluid leakage (outer overlapping area)> 5, the working fluid leakage prevention means for the pair of outer overlapping regions 21jb, 22jb is to provide an axial hole sealing portion 81C made of an annular protrusion so as to cover the entire outer overlapping region 22jb on the other side. This axial hole sealing portion 81C is made of a plastic processing portion 81s provided by plastic processing so as to cover the entire outer overlapping region 22jb on the other side.

[0072] In this way, a ring-shaped jig (not shown) is used as the axial sealing portion 81C to crush and plastically deform the other outer overlapping region 22jb from above. As a result, the axial cavity P to be exposed in the other outer overlapping region 22jb can be reliably sealed because the ring-shaped protrusion is physically crushed. Therefore, even if the working fluid attempts to enter the axial cavity P through the other outer overlapping region 22jb in the direction of arrow A in FIG. 5, the path of the working fluid is blocked by the sealing region Rs3 to which the axial sealing portion 81C is applied, and as a result, the working fluid does not leak into the external space outside the fluid path.

[0073] In this embodiment, the plastic processing portion 81s is made of an annular convex portion, so that the inner diameter of the sealing region Rs3 where the axial sealing portion 81C is applied to the outer overlap region 21jb on one side can be set by the inner diameter of the annular convex portion. This makes it easy to manage the position of the sealing region Rs3. In this embodiment, the axial sealing portion 81C is provided so as to cover the entire outer overlap region 22jb on the other side. However, this is not limited to this, and for example, the axial sealing portion 81C may be provided so as to cover the entire outer overlap region 21jb on one side, or may be provided in both the outer overlap region 21jb on one side and the outer overlap region 22jb on the other side, and the region where the axial sealing portion 81C is provided may be provided over the entire pair of overlapping outer overlap regions 21jb, 22jb as viewed from the axis L direction. In addition, the axial sealing portion 81C in this embodiment can be relatively easily provided by adopting plastic processing, without using additional members such as brazing material or large-scale equipment such as welding. Furthermore, the plastic processing in this embodiment uses a jig having a ring shape, but is not limited to this, and may be, for example, shot peening, shot blasting, etc. In addition, in this embodiment, the axial sealing portion 81C consisting of an annular convex portion is provided in the outer overlapping region 22jb on the other side, but is not limited to this, and may be, for example, a flat axial sealing portion 81C. As a result, the inner diameter of the sealing region Rs3 where the axial sealing portion 81C is provided can be set by the inner diameter of the annular jig for the outer overlapping region 21jb on one side, making it easy to manage the position of the sealing region Rs3. In addition, in this embodiment, the other outer overlap region 22jb is crushed from above to form the plastically processed portion 81s formed by plastic processing, but this is not limited to the above, and the surface of the inner side wall 24a may be crushed radially inward perpendicular to the axial direction to form the plastically processed portion formed by plastic processing.

[0074] In this way, the third embodiment also has the same effect as the second embodiment, that is, by providing the working fluid leakage prevention means so as to cover the entire outer overlapping region 22jb on the other side, the conventional problem (leakage of the working fluid through the axial cavity) can be eliminated even if the valve seat portion 20C has a material defect such as a porosity. Also, in the third embodiment, the working fluid leakage prevention means employs the inner region Rp1 of the second joint pipe 2, so that leakage of the working fluid in the pair of inner overlapping regions 21ja, 22ja can be reliably prevented without increasing the number of parts, etc. Furthermore, in the third embodiment, a sealing region Rs1' (see Figure 2(c)) in which a circumferential sealing portion 82 is provided in the inner side wall 24a of the valve seat portion 20C is provided. Therefore, even if the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 24a and then moves in the direction of arrow A near the inner side wall 24a of the valve seat portion 20C, the working fluid will not leak into the external space outside the fluid path because its path is blocked by the sealing region Rs1' in which the circumferential sealing portion 82 is provided.

[0075] <About the valve seat assembly process> In the assembly process of the valve seat portion 20C, when the axial sealing portion 81C is provided in the outer overlapping region 22jb on the other side as shown in FIG. 5, the outer overlapping region 22jb on the other side of the valve seat portion 20C is first subjected to plastic working to provide the axial sealing portion 81C. Next, the inner side wall 124a is inserted into the fitting hole 10a of the valve body 10, and the mounting step portion 24c of the valve seat portion 20C is brazed and fixed. This provides the circumferential sealing portion 82, which becomes a cylindrical region. Furthermore, the first joint pipe 1 is brazed and fixed to the valve body 10, and at the same time, the second joint pipe 2 is brazed and fixed to the insertion hole 23 of the valve seat portion 20C, thereby defining the inner region Rp1 of the second joint pipe 2.

[0076] In this embodiment, since the process of providing the axial sealing portion 81C can be added simply before the conventional assembly process, the assembly process can be prevented from becoming complicated.

[0077] On the other hand, when the axial sealing portion 81C is provided in the outer overlapping region 21jb on one side, first, the inner side wall 124a is inserted into the fitting hole 10a of the valve body 10, and the mounting step portion 24c of the valve seat portion 20C is brazed and fixed. This provides a circumferential sealing portion 82 that is a cylindrical region. Next, after the second coupling pipe 2 is inserted into the insertion hole 23 of the valve seat portion 20C, the outer overlapping region 21jb on one side is subjected to plastic processing, and the axial sealing portion 81C is provided. At this time, the insertion hole 23 into which the second coupling pipe 2 is inserted is slightly distorted by plastic processing, so that the second coupling pipe 2 can be temporarily fixed. Furthermore, the first coupling pipe 1 is brazed and fixed to the valve body 10, and at the same time, the second coupling pipe 2 is brazed and fixed to the insertion hole 23 of the valve seat portion 20A.

[0078] In this embodiment, the process of providing the axial sealing portion 81C can be achieved by simply changing the order of the previous assembly processes slightly and adding it to the rearranged assembly processes, thereby preventing the assembly processes from becoming complicated.

[0079] In the first to third embodiments, the axial sealing parts 81A, 81B, and 81C are individually used for either one of the pair of outer overlapping regions 21jb and 22jb, but the present invention is not limited to this, and for example, a combination of the axial sealing parts 81A, 81B, and 81C may be used for at least one of the pair of outer overlapping regions 21jb and 22jb. In the first to third embodiments, the order of the process of providing the axial sealing parts 81A, 81B, and 81C may be changed as appropriate, for example, the valve body and the valve seat part may be brazed to the first joint pipe and the second joint pipe simultaneously, depending on the manufacturing equipment and assembly process.

[0080] (Fourth embodiment) Here, a valve seat portion 120 according to a fourth embodiment will be described with reference to Fig. 6. The valve seat portion 120 in this fourth embodiment differs from the valve seat portion 20A in the first embodiment in the internal region Rp2 of the second joint pipe 102 provided in the overlapping region 121j on one side, but the other basic configuration is the same as that of the first embodiment. Here, the same members are given the same reference numerals, and duplicated explanations (<Regarding the working fluid leakage prevention means (cylindrical region)>) are omitted, and <Regarding the working fluid leakage prevention means (overlapping region)> and <Regarding the assembly process of the valve seat portion> will be described.

[0081] In the first to third embodiments (see Figs. 2(a), 4 and 5), first, the pair of overlapping regions 21j, 22j is divided into a pair of inner overlapping regions 21ja, 22ja and a pair of outer overlapping regions 21jb, 22jb by using the joint portion 2a of the second joint pipe 2. The inner overlapping region 21ja on one side is disposed in the internal region Rp1 of the second joint pipe 2, and the axial sealing portions 81A, 81B, 81C are provided in one of the pair of outer overlapping regions 21jb, 22jb to prevent leakage of the working fluid through the valve seats 20A, 20B, 20C. However, as described above, in the assembly process of the valve seats 20A, 20B, 20C, a relatively high positional accuracy is required to provide the axial sealing portions 81A, 81B, 81C, and the conventional assembly process needs to be slightly changed, which may cause a bottleneck in the production line. Therefore, there has been a demand for a valve seat portion that does not employ the axial sealing portions 81A, 81B, and 81C as a working fluid leakage prevention means and that can be used without changing the assembly process of the conventional valve seat portion.

[0082] Therefore, in the valve seat portion 120 according to the fourth embodiment, the internal region Rp2 of the second joint pipe 102 is made relatively large, and the entire overlapping region 121j on one side is disposed in this internal region Rp2. As a result, the valve seat portion 120 omits the axial sealing portions 81A, 81B, 81C, and the working fluid leakage prevention means has a simpler configuration, and the assembly process of the conventional valve seat portion can be adopted as it is without any changes.

[0083] <Means for preventing working fluid leakage (overlapping area)> 6, the second joint pipe 102 includes a base 102b and a joint portion 102a having an inner diameter Da1 larger than an inner diameter Da2 of the base 102b. The joint portion 102a of the second joint pipe 102 is inserted into and joined to an insertion hole 123 of a valve seat portion 120 having an inner diameter slightly larger than an outer diameter of the joint portion 102a. Since the inner diameter Da1 of the joint portion 102a is set to be greater than the inner diameter Da2 of the base 102b, the area of ​​the internal region Rp2 of the second joint pipe 102 can be enlarged, and the size of the pipe diameter is set to be relatively small in the base 102b, which occupies most of the second joint pipe 102, as will be described later in detail, so that the valve device 100 can be made more space-saving.

[0084] Here, the outer diameter DA of the joint 102a of the second joint pipe 102 is set to be larger than the inner diameter DB of the fitting hole 10a of the valve body 10 (DA>DB). The outer diameter DA of the joint 102a is the same as the internal region Rp2 of the second joint pipe 102, and the inner diameter DB of the fitting hole 10a is the same as the inner diameter of the pair of overlapping regions 121j, 122j. Therefore, "outer diameter DA of the joint 102a>inner diameter DB of the fitting hole 10a" indicates "internal region Rp2 of the second joint pipe 102>inner diameter of the overlapping region 121j on one side", and if this size relationship is satisfied, the entire overlapping region 121j on one side will always be disposed in the internal region Rp2 of the second joint pipe 102. As a result, even if the working fluid moves in the direction of arrow A in Figure 6 from the overlapping region 122j on the other side through the axial cavity P to the overlapping region 121j on one side, this working fluid will not leak into the external space outside the fluid path, because it is located in the internal region Rp2 of the second joint pipe 102.

[0085] In this way, the valve seat portion 120 in the fourth embodiment can arrange the entire overlap region 121j on one side in the internal region Rp2 of the second joint pipe 102 as a working fluid leakage prevention means by simply expanding the inner diameter of the insertion hole 23 of the valve seat portion 20A in the first embodiment (≈ outer diameter D of the joint portion of the second joint pipe) to the inner diameter of the insertion hole 123 (≈ outer diameter DA of the joint portion of the second joint pipe). As a result, the valve seat portion 120 in the fourth embodiment can omit the axial sealing portions 81A, 81B, 81C without increasing the number of parts, etc., and even if the valve seat portion 120 has a material defect such as a porosity, the conventional problem (leakage of the working fluid through the axial cavity) can be eliminated. Furthermore, in the fourth embodiment, the same effect as in the first embodiment is achieved, that is, the working fluid leakage prevention means is provided in the inner side wall 124a of the valve seat portion 120 with a sealing region Rs1' (see Figure 2 (c)) in which a circumferential sealing portion 82 is provided. Even if the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 124a and then moves in the direction of arrow A near the inner side wall 124a of the valve seat portion 120, the path of the working fluid is blocked by the sealing region Rs1' in which the circumferential sealing portion 82 is provided, thereby preventing leakage.

[0086] <About the valve seat assembly process> In the process of assembling the valve seat portion 120, first, the inner side wall 124a, which has an outer diameter slightly smaller than the inner diameter of the fitting hole 10a, is inserted into the fitting hole 10a of the valve body 10, and the mounting step portion 124c of the valve seat portion 120 is brazed and fixed. This provides a circumferential sealing portion 82 that becomes a cylindrical region. Next, the first joint pipe 1 is brazed and fixed to the valve body 10, and at the same time, the joint portion 102a of the second joint pipe 102 is inserted into the insertion hole 123 of the valve seat portion 120 and brazed and fixed.

[0087] In this embodiment, the conventional valve seat assembly process can be used without modification, and therefore the present invention can be smoothly introduced.

[0088] Fifth embodiment Here, a valve seat portion 220 according to a fifth embodiment will be described with reference to Fig. 7. The valve seat portion 220 in this fifth embodiment differs from the valve seat portion 120 in the fourth embodiment in that it is inserted into and joined to the joint portion 102a of the second joint pipe 102, but the other basic configuration is the same as that of the fourth embodiment. Here, the same members (particularly the second joint pipe 102, etc.) are given the same reference numerals, and duplicated explanations (<Regarding the working fluid leakage prevention means (cylindrical region)>) are omitted, and only <Regarding the working fluid leakage prevention means (overlapping region)> and <Regarding the valve seat portion assembly process> will be described.

[0089] In the valve seat portion 120 in the fourth embodiment (see FIG. 6), the outer side wall 124b is arranged outside the internal region Rp2 of the second joint pipe 102 in order to insert and join the joint portion 102a of the second joint pipe into the insertion hole 123. In contrast to this, in the valve seat portion 220 in the fifth embodiment, the insertion tube 225 is arranged in the internal region Rp2 of the second joint pipe 102 in order to insert and join the insertion tube 225 into the joint portion 102a of the second joint pipe. As a result, in the valve seat portion 220 in the fifth embodiment, as in the fourth embodiment, the internal region Rp2 of the second joint pipe 102 is made relatively large, and all of the overlapping region 221j (including the insertion tube 225) on one side is disposed in this internal region Rp2, thereby preventing leakage of the working fluid through the valve seat portion 220, and by using the difference in flow path resistance of the working fluid in the axial cavity P within the valve seat portion 120, leakage of the working fluid to the external space is more reliably prevented.

[0090] <Means for preventing working fluid leakage (overlapping area)> Specifically, as shown in FIG. 7, the second joint pipe 102 is made of stainless steel material, has the same shape as that of the fourth embodiment, and includes a base 102b and a joint portion 102a having an inner diameter Da1 larger than the inner diameter Da2 of the base 102b. The valve seat portion 220 is made of stainless steel material, and includes an inner side wall 224a inserted into the fitting hole 10a, an outer side wall 224b exposed to the outside space, and an attachment step portion 224c located between the inner side wall 224a and the outer side wall 224b and engaging with the fitting hole 10a. The valve seat portion 220 also includes an insertion tube 225 having a cylindrical shape extending to one side in an overlapping region 221j on one side. The insertion tube 225 of the valve seat portion 220 is inserted and joined into the joint portion 102a having an inner diameter slightly larger than the outer diameter of the insertion tube 225. As in the fourth embodiment, since the inner diameter Da1 of the joint 102a is set to be greater than the inner diameter Da2 of the base 102b, the area of ​​the internal region Rp2 of the second joint pipe 102 can be enlarged, and since the piping diameter of the base 102b, which occupies most of the second joint pipe 102, is set to be relatively small, the space required for the valve device 100 can be saved.

[0091] Here, as in the fourth embodiment, the outer diameter DA of the joint 102a of the second joint pipe 102 is set to be larger than the inner diameter DB of the fitting hole 10a of the valve body 10 (DA>DB). The outer diameter DA of the joint 102a is the same as the inner region Rp2 of the second joint pipe 102, and the inner diameter DB of the fitting hole 10a is the same as the inner diameter of the pair of overlapping regions 221j, 222j. Therefore, "outer diameter DA of the joint 102a>inner diameter DB of the fitting hole 10a" indicates "inner region Rp2 of the second joint pipe 102>inner diameter of the overlapping region 221j on one side", and if this size relationship is satisfied, the entire overlapping region 221j on one side will always be disposed in the inner region Rp2 of the second joint pipe 102. As a result, even if the working fluid moves in the direction of arrow A in Figure 7 from the overlapping region 222j on the other side through the axial cavity P to the overlapping region 221j on one side, this working fluid will not leak into the external space outside the fluid path, because it is located in the internal region Rp2 of the second joint pipe 102.

[0092] Furthermore, in the valve seat portion 220 in the fifth embodiment, the axial distance L1 (including the insertion tube) from one end (lower end) of the insertion tube 225 provided in the overlapping region 221j on one side to the overlapping region 222j on the other side is set to be longer than the axial distance L2 (excluding the insertion tube) from the overlapping region 221j on one side where the insertion tube 225 is not provided to the overlapping region 222j on the other side. Here, assume a case in which the overlapping region 221j on one side is communicated with the overlapping region 222j on the other side through a plurality of continuous axial cavities P. Since the flow resistance of the working fluid in each axial cavity P increases in proportion to the axial distance of each axial cavity P, the working fluid tends to selectively flow into the axial cavity P not including the insertion tube, rather than into the axial cavity P including the insertion tube. In other words, the working fluid is released from near the center of the internal region Rp2 of the second joint pipe 102 through the overlap region 221j on one side where the insertion tube 225 is not provided, which is radially inward from the insertion tube 225, i.e., the safer side against leakage, so as to avoid the joint between the insertion tube 225 and the joint portion 102a, thereby more reliably preventing leakage of the working fluid into the external space.

[0093] In this way, in the fifth embodiment, the same effect as in the fourth embodiment is achieved, that is, by arranging all of the overlapping region 221j on one side in the internal region Rp2 of the second joint pipe 102 as a working fluid leakage prevention means, the axial sealing portions 81A, 81B, 81C can be omitted without increasing the number of parts, etc., and even if the valve seat portion 220 has a material defect such as a cavity, the conventional problem (leakage of working fluid through the axial cavity) can be eliminated. Also, in the fifth embodiment, the working fluid leakage prevention means provides a sealing region Rs1' (see Figure 2(c)) in which a circumferential sealing portion 82 is provided on the inner side wall 224a of the valve seat portion 220. Even if the working fluid flows into the opening of the axial cavity P exposed and opened on the surface of the inner side wall 224a and then moves in the direction of arrow A near the inner side wall 224a of the valve seat portion 220, the path of the working fluid is blocked by the sealing region Rs1' in which the circumferential sealing portion 82 is provided, thereby preventing leakage. Furthermore, in the fifth embodiment, by arranging the insertion tube 225 in the overlapping region 221j on one side in the internal region Rp2 of the second joint pipe 102 and setting the axial distance (including the insertion tube) L1 longer than the axial distance (excluding the insertion tube) L2, the working fluid is selectively released from near the center of the internal region Rp2 of the second joint pipe 102 through the overlapping region 221j on the one side where the insertion tube 225 is not provided, thereby more reliably preventing leakage of the working fluid into the external space.

[0094] <About the valve seat assembly process> In the process of assembling the valve seat portion 220, first, the inner side wall 224a, which has an outer diameter slightly smaller than the inner diameter of the fitting hole 10a, is inserted into the fitting hole 10a of the valve body 10, and the mounting step portion 224c of the valve seat portion 220 is brazed and fixed. This provides a circumferential sealing portion 82 that becomes a cylindrical region. Next, the first joint pipe 1 is brazed and fixed to the valve body 10. Also, the insertion tube 225 of the valve seat portion 220 is inserted into the joint portion 102a of the second joint pipe 102 and fixed by welding.

[0095] In this embodiment, instead of brazing the second joint pipe 102 to the valve seat portion 220 as in the conventional valve seat portion assembly process, it is possible to simply weld the second joint pipe 102 to the valve seat portion 220, thereby preventing the assembly process from becoming complicated.

[0096] <Other> It goes without saying that the valve seats 20, 20A, 20B, 20C, 120, and 220 of the valve device 100 of this embodiment are applicable to all fluid devices and fluid circuits, including refrigeration cycles. Furthermore, the present invention is not limited to the above-mentioned aspects, embodiments, and modified examples, and can be modified and changed as appropriate without departing from the technical concept of the present invention. [Explanation of symbols]

[0097] 100 Valve gear 1 First joint pipe 10 Valve body 10a Fitting hole 102b base 2,102 Second joint pipe 2a,102a joint 20,20A,20B,20C,120,220 Valve seat 20a, 120a, 220a valve port 21,121,221 Axial cutting surface on one side 21j, 121j, 221j Unilateral overlapping area 21ja Unilateral medial overlapping area 21jb Unilateral lateral overlapping region 22,122,222 Axial cutting surface on the other side 22j, 122j, 222j Other side overlapping area 22ja Other side medial overlapping area 22jb Other side lateral overlapping area 23,123 Insertion hole 24a,124a,224a Internal side wall 24b,124b,224b External side wall 24c, 124c, 224c Mounting step 225 Insertion tube 30 Support member 31 Holder part 32 Fixed part 33 Screw hole 33a Female thread 35 Slide hole 40 Drive shaft 50 Valve body 60 Stepping Motor 70 Rotation stopper mechanism 81A, 81B, 81C Axial sealing section 81c Recess 81r Brazing material 81s Plastic processing department 81w welding part 82 Circumferential sealing part 82r Brazing material D, DA Outside diameter of the joint of the second joint pipe Da1 Inner diameter of joint Da2 Base inner diameter DB fitting hole inner diameter L axis L1 Axial distance (including insertion tube) L2 Axial distance (not including insertion tube) P axial cavity r Brazing material Rp1, Rp2: Inner area of ​​second joint pipe Rs1,Rs1',Rs2,Rs3 Sealing area

Claims

1. A valve body formed of a thin plate and defining an internal space; a valve seat portion which is made of a push rod or a pull rod, has a pair of axial cut surfaces formed by cutting, and a valve port which penetrates between the pair of axial cut surfaces, and is joined from one axial end side to a fitting hole provided at one axial end of the valve body; a valve body for changing an opening degree of the valve port, When the valve seat portion is viewed from the axial direction, a pair of overlapping regions is defined as a pair of overlapping regions, where the axial cut surface on one side and the axial cut surface on the other side overlap each other, In the pair of overlapping regions, a differential pressure between inside and outside the fluid path is applied in the axial direction, and at least one of the overlapping regions on one side and the overlapping region on the other side is provided with at least a working fluid leakage prevention means so that the working fluid does not leak. A valve device, characterized in that, when viewed from the axial direction, a region in which the working fluid leakage prevention means is provided is provided across the entirety of the pair of overlapping regions.

2. The working fluid leakage prevention means includes an axial sealing portion, By joining a joint portion of a joint pipe to the valve seat portion, the pair of overlapping regions are defined as a pair of inner overlapping regions and a pair of outer overlapping regions located radially inward and radially outward from the joint portion, The inner overlap region on one side is disposed in an inner region of the coupling pipe; 2. The valve device according to claim 1, wherein the axial sealing portion is provided in one of the pair of outer overlapping regions.

3. 3. The valve device according to claim 2, wherein the axial sealing portion is formed by adhering a molten and solidified brazing material.

4. 4. The valve device according to claim 3, wherein the brazing material in the axial sealing portion is accommodated in a recess formed so as to cover the entirety of either one of the pair of outer overlapping regions.

5. 3. The valve device according to claim 2, wherein the axial sealing portion is formed by welding.

6. 3. The valve device according to claim 2, wherein the axial sealing portion is formed by applying plastic working.

7. The working fluid leakage prevention means further includes:

3. The valve device according to claim 2, wherein, when joining the valve seat to the valve body, a circumferential sealing portion is provided by adhering a molten and solidified brazing material to a cylindrical region along a side surface of the valve seat.

8. The working fluid leakage prevention means includes: The outer diameter of the joint portion of the joint pipe is set to be larger than the inner diameter of the fitting hole of the valve body, and the joint portion of the joint pipe is joined to the valve seat portion, 2. The valve device according to claim 1, wherein the entire overlap region on one side is disposed in the inner region of the connector pipe.

9. The valve device according to claim 8, wherein the joint portion of the joint pipe is inserted into and joined to an insertion hole of the valve seat portion.

10. The valve device according to claim 8, wherein the insertion tube of the valve seat is inserted into and joined to the joint portion of the coupling pipe.

11. 9. The valve assembly according to claim 8, wherein the coupling pipe comprises a base portion and the mating portion has an inner diameter larger than an inner diameter of the base portion.

Images