Valve device and refrigeration cycle system

Abstract

To provide a valve device and a refrigeration cycle system capable of improving sealing performance.SOLUTION: A check valve 1 comprises a cylindrical body 10 through which fluid flows, a valve seat member 20 press-fitted into the body 10, and a valve body 50 that opens and closes a valve port 31 provided in the valve seat member 20. A press-fitting part 33 is provided on an outer surface of the valve seat member 20. A part to be press-fitted 13 is provided on an inner surface of the body, with the press-fitting part 33 coming into slide contact from the other side L2 to one side L1. A protruding surface part 15 that protrudes toward the inside of the body 10 is provided on the one side L1 with respect to an end part of the other side L2 of the press-fitting part 13, and a seal part S that stops fluid leakage is formed by a close contact part between the protruding surface part 15 and the press-fitting part 33 of the valve seat member 20.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] A valve device for controlling the flow of a fluid is known (see, for example, Patent Document 1). The valve device (check valve) described in Patent Document 1 includes a tubular valve body housing portion, a cylindrical valve seat member housed in the valve body housing portion, and a valve body (valve main body) that opens and closes a valve port formed in the valve seat member. In this valve device, the valve port is opened and closed by the valve body moving forward and backward in the axial direction within the valve body housing portion, thereby controlling the flow of the fluid. The valve seat member is press-fitted into the valve body housing portion in the axial direction, and the space between the outer wall of the valve seat member and the inner wall of the valve body housing portion is sealed by this press-fitting.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a valve device as described above may be used, for example, as a valve device that constitutes a part of a refrigeration cycle system. At this time, as the fluid to be controlled by the valve device, a super-high pressure fluid such as CO2 may be used in some cases. In this case, due to the super-high pressure, the force acting in the direction of expanding the inner diameter of the inner wall of the valve body housing portion is large. Therefore, in a structure where the valve seat member is simply press-fitted into the valve body housing portion as in a conventional valve device, the seal between the outer wall of the valve seat member and the inner wall of the valve body housing portion is not sufficient, and there is a possibility of back leakage where the fluid leaks out to an unintended part. Further, due to this back leakage, the energy efficiency of the refrigeration cycle system may decrease, and the energy-saving performance of the valve device may deteriorate.

[0005] An object of the present invention is to provide a valve device and a refrigeration cycle system that improve sealing performance.

Means for Solving the Problems

[0006] In order to solve the above problems and achieve the object, a valve device of the present invention includes a cylindrical main body that extends from one side to the other side and through which fluid flows, a valve seat member press-fitted into the main body, and a valve body that opens and closes a valve port provided in the valve seat member. The valve device is characterized in that it includes a press-fitting portion provided on the outer surface of the valve seat member, and a press-fitted portion provided on the inner surface of the main body, with which the press-fitting portion is slidably contacted from the other side to the one side. A protruding surface portion that protrudes inward of the main body is provided on the one side rather than the other side end portion of the press-fitted portion, and a seal portion that stops leakage of the fluid is formed by a close contact portion between the press-fitting portion and the protruding surface portion.

[0007] According to such a present invention, by providing a protruding surface portion on the press-fitted portion of the inner surface of the main body and forming a seal portion by the close contact portion between the press-fitting portion of the valve seat member and the protruding surface portion, back leakage in which the fluid flowing in the main body leaks to an unintended portion can be reliably prevented by the seal portion. Thereby, the sealing performance of the valve device can be improved. For this reason, even when a fluid with an ultra-high pressure such as CO2 is used as the fluid to be controlled by the valve device, a higher sealing performance can be maintained as compared with a structure in which the valve seat member is simply press-fitted into the valve body housing portion as in the conventional valve device. Therefore, a valve device that improves sealing performance can be provided.

[0008] Further, at this time, it is preferable that the protruding surface portion is composed of an existing surface portion formed before the valve seat member is press-fitted. According to such a configuration, by forming the protruding surface portion by the existing surface portion formed before the valve seat member is press-fitted, the press-fitting portion of the valve seat member is brought into close contact with the existing surface portion formed in advance in the main body to form a seal portion. Therefore, even when an ultra-high pressure fluid is used as the control target of the valve device, back leakage of the fluid can be prevented as compared with a conventional valve device having no existing surface portion in close contact with the press-fitting portion of the valve seat member. In addition, the sealing property of the valve device can be maintained at a high level.

[0009] Further, the protruding surface portion is formed with a predetermined angle with respect to the axis of the main body extending from the one side to the other side. According to such a configuration, the protruding surface portion can be formed into various shapes, such as, for example, a tapered shape inclined with respect to the axis of the main body or a right-angled shape orthogonal to the axis of the main body. Further, since the angle of the protruding surface portion with respect to the axis can be set to a predetermined angle, by changing the angle, the close state between the press-fitting portion and the protruding surface portion can be appropriately changed according to conditions such as the materials of the main body and the valve seat member. Therefore, the sealing performance of the valve device can be maintained at a high level.

[0010] Further, the main body and the valve seat member are provided in a cylindrical shape, and the press-fitting portion includes a press-fitting allowance portion provided on the other side, a small-diameter portion provided on the one side, and the protruding surface portion provided between the press-fitting allowance portion and the small-diameter portion. The press-fitting allowance portion has an inner diameter dimension before press-fitting the valve seat member smaller than the outer diameter dimension of the press-fitting portion in the valve seat member before press-fitting. The small-diameter portion has an inner diameter dimension equal to or smaller than the inner diameter dimension of the press-fitting allowance portion. It is preferable that the end portion on the other side of the protruding surface portion is continuous with the press-fitting allowance portion, and the end portion on the one side of the protruding surface portion is continuous with the small-diameter portion. According to such a configuration, the valve seat member can be reliably press-fitted into the main body, and a seal portion can be reliably formed between the protruding surface portion and the press-fitting portion.

[0011] Also, it is preferable that the thickness dimension of the small-diameter portion is larger than the thickness dimension of the press-fitting allowance portion. In a valve device, for example, the valve seat member press-fitted into the main body may be fixed to the main body by caulking the small-diameter portion inward in the radial direction. In this case, due to the formation of the caulked portion where the caulking is performed, a portion where the thickness dimension is partially reduced may occur in the small-diameter portion. In this case, stress is likely to concentrate in the caulked portion when it is subjected to the pressure of ultra-high-pressure fluid, and the pressure resistance of the main body may locally decrease. However, according to this configuration, when the caulked portion is formed, although the thickness dimension of the small-diameter portion is partially reduced at the portion of the caulked portion, since the original thickness dimension of the small-diameter portion is larger than the thickness dimension of the press-fitting allowance portion, the pressure resistance of the main body does not locally decrease. Therefore, it is easy to prevent cracks in the main body, and by preventing such cracks, the risk of external leakage of fluid can be reduced, and the reliability of the valve device with respect to ultra-high-pressure fluid can be improved.

[0012] Also, it is preferable that the outer diameter dimension of the small-diameter portion is equal to the outer diameter dimension of the press-fitting allowance portion. According to such a configuration, since the outer diameter dimension of the small-diameter portion is equal to the outer diameter dimension of the press-fitting allowance portion, no step or the like due to the difference in outer diameter dimension occurs in the main body. Therefore, it is difficult for the main body to form stress-concentrating portions such as the boundary portion of the step. Therefore, it is easy to prevent stress corrosion cracking due to stress concentration, and the reliability of the valve device with respect to ultra-high-pressure fluid can be improved.

[0013] Also, the check valve of the present invention is characterized by being configured by the valve device according to any one of the above. According to such a present invention, a check valve can be configured using a valve device that improves sealing performance.

[0014] Also, the refrigeration cycle system of the present invention is characterized by including the check valve described above. According to such a present invention, since a refrigeration cycle system can be configured using a check valve that improves sealing performance, the energy efficiency of the refrigeration cycle system is improved.

[0015] Also, on the other side of the press-fitting allowance portion, a large-diameter portion having a larger inner diameter than the press-fitting allowance portion is provided. The valve seat member is provided with a flange portion that protrudes toward the inner surface of the main body and abuts against the boundary portion between the large-diameter portion and the press-fitting allowance portion on the inner surface. The space surrounded by the flange portion and the portion other than the flange portion in the valve seat member, and the press-fitting allowance portion in the main body constitutes an oil reservoir portion capable of storing the oil contained in the fluid. The flange portion is provided with an oil introduction portion that communicates the oil reservoir portion with the inside of the main body. It is preferable that the oil reservoir portion and the oil introduction portion constitute a working fluid leakage prevention portion that suppresses leakage of the fluid. According to such a configuration, the oil stored in the oil reservoir portion can be supplied between the outer surface of the valve seat member and the inner surface of the main body by capillary action. Thereby, for example, if there is a minute gap or scratch between the press-fitting portion on the outer surface of the valve seat member and the press-fitting allowance portion on the inner surface of the main body, the back leakage of the fluid can be more reliably suppressed by this oil. Further, the oil stored in the oil reservoir portion is difficult to move to the other side when the flange portion abuts against the main body. Therefore, compared with a configuration in which a gap is simply provided between the valve seat member and the main body to form an oil reservoir portion, the following can be suppressed. That is, it is possible to prevent a so-called ejector effect in which the oil is involved in the flow of the fluid around the oil reservoir portion and the oil is sucked out from the oil reservoir portion.

[0016] Further, the main body has a holding force strengthening portion that strengthens the holding force of the press-fitted portion. The holding force strengthening portion is constituted by the press-fitting allowance portion subjected to plastic working. It is preferable that the thickness dimension of the press-fitting allowance portion is smaller than the thickness dimension of the small-diameter portion. According to such a configuration, for example, by applying plastic working such as spinning processing to the press-fitting allowance portion, the hardness of the press-fitting allowance portion can be made higher than the hardness of the small-diameter portion, and the press-fitting allowance portion can be made difficult to deform. Therefore, even if the structure inside the main body undergoes repeated changes such as expansion or contraction due to changes in pressure and temperature, the holding strength of the valve seat member with respect to the press-fitting portion can be maintained high, the sealing performance of the seal portion can be stabilized, and the pull-out strength of the valve seat member can be improved.

[0017] Further, on the outer periphery of the valve seat member, a corner portion having a surface facing the other end portion of the valve seat member is provided, and on the main body, a caulking portion caulked inward is provided, and it is preferable that the caulking portion is provided with a caulking convex portion that engages with the corner portion. According to such a configuration, by engaging the caulking convex portion of the caulking portion provided on the main body with the corner portion of the valve seat member, loosening of the caulking in the caulking portion can be suppressed, and the holding force of the valve seat member in the main body can be further improved, so that the pull-out strength of the valve seat member can be further improved.

[0018] Further, it is preferable that the caulking convex portion is constituted by a tip portion of the caulking portion that is formed by punch caulking on the outer periphery of the main body and protrudes inward of the main body. According to such a configuration, compared with a so-called roll caulking structure in which caulking is performed over the entire circumference of the main body, the stress generated in the caulking portion can be reduced. Therefore, cracking of the main body and external leakage of fluid due to the cracking can be suppressed.

[0019] Further, it is preferable that the caulking convex portion bites into at least a part of the corner portion, and the bitten portion constitutes a working fluid leakage prevention portion that suppresses leakage of the fluid. According to such a configuration, by biting the caulking convex portion of the main body into at least a part of the corner portion of the valve seat member, loosening of the caulking in the caulking portion is further suppressed, and the press-fitted valve seat member is less likely to loosen with respect to the main body. Therefore, the holding force of the valve seat member by the main body can be further improved, so that the pull-out strength of the valve seat member can be further improved. Also, at this time, the valve seat member and the main body will approach each other in the biting direction. As a result, the press-fitted portion constituting the seal portion will be closer to the protruding surface portion, and the surface pressure of the seal portion can be increased. Therefore, the sealing performance of the seal portion is further improved. Accordingly, the bitten portion constitutes a working fluid leakage prevention portion that suppresses leakage of the fluid, and back leakage of the fluid can be suppressed.

[0020] On the one side of the valve seat member, an annular recess that is recessed inward is provided. One end of the annular recess on the one side constitutes the corner portion. In the axial direction of the main body, the dimension from one end of the valve seat member on the one side to the corner portion is preferably 0.5 times or more of the dimension from the corner portion to the other end of the caulking convex portion. According to such a configuration, in the valve seat member, the axial dimension from the portion where the corner portion is formed to one end on the one side can be ensured, and the strength of one side portion of the valve seat member can be ensured. Therefore, deformation of one side portion of the valve seat member can be suppressed, and when the caulking convex portion is engaged with the corner portion, the pull-out strength of the valve seat member can be further improved.

Advantages of the Invention

[0021] According to the present invention, a valve device and a refrigeration cycle system that improve sealing performance can be provided.

Brief Description of the Drawings

[0022]

Figure 1

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Figure 10

Figure 11

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Figure 13

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Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Best Mode for Carrying Out the Invention

[0023] Hereinafter, the check valve 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 10. The check valve 1 according to the present embodiment is a valve device that controls (allows flow, blocks) the flow of fluid, and is installed and used, for example, in the middle of the fluid flow path in the refrigeration cycle system 100 described later. In the following description, the direction along the axis L of the main body 10 described later is referred to as the "axis L direction", one side in the axis L direction is referred to as "one side L1", and the other side in the axis L direction is referred to as "the other side L2". Further, the direction from one side L1 to the other side L2 is defined as the forward flow direction in the fluid flow direction, and the direction toward the opposite side of the forward flow direction is defined as the reverse flow direction. This is only for the convenience of explanation and does not necessarily coincide with the direction in the actual use state of the check valve 1, nor does it limit each direction in the actual use state of the check valve 1.

[0024] As shown in FIG. 1, the check valve 1 includes a main body 10 extending from one side L1 to the other side L2. Fluid flows through the main body 10 in the forward flow direction or the reverse flow direction, but the flow in the reverse flow direction is stopped by a valve body 50 described later. The main body 10 is formed in a cylindrical shape (tubular shape) using a metal material such as copper, for example, and includes a valve main body 11 extending in the axis L direction. A large-diameter portion 12 is formed on the other side L2 of the inner peripheral surface (inner surface) of the valve main body 11. The large-diameter portion 12 is the portion with the largest inner diameter dimension in the valve main body 11 and has a cylindrical shape. A press-fitting portion 13 having an inner diameter dimension smaller than that of the large-diameter portion 12 is continuously formed on one side L1 of the large-diameter portion 12 and extends toward one side L1. The press-fitting portion 33 of the valve seat member 20 press-fitted into the valve main body 11 is slidably contacted (press-fitted) into the press-fitting portion 13 from the other side L2 toward one side L1.

[0025] As shown in FIGS. 2(A) and 3(A), the press-fitting portion 13 includes a press-fitting allowance portion 14, a protruding surface portion 15, and a small-diameter portion 16 from the other side L2 toward the one side L1. Note that the "press-fitting allowance" of the "press-fitting allowance portion 14" generally refers to the radial dimension difference between the outer diameter dimension β1 of the press-fitting portion 33 of the valve seat member 20 and the inner diameter dimension of the press-fitting portion 13 of the valve body 11. The "press-fitting allowance portion 14" represents the range in the axial direction L where this "press-fitting allowance" exists in the valve body 11. The press-fitting allowance portion 14 is formed in a cylindrical shape continuously with the large-diameter portion 12. In the press-fitting allowance portion 14 shown in FIG. 2(A), the inner diameter dimension α1 before press-fitting the valve seat member 20 is set to be smaller than the inner diameter dimension of the large-diameter portion 12 and smaller than the outer diameter dimension β1 of the press-fitting portion 33 of the valve seat member 20 before press-fitting shown in FIG. 2(B). Due to the difference (press-fitting allowance) between this inner diameter dimension α1 and the outer diameter dimension β1, the press-fitting of the valve seat member 20 to the valve body 11 is surely performed. As shown in FIG. 3(A), the protruding surface portion 15 is an inner wall surface protruding radially inward (inward of the main body 10). The end on the other side L2 is continuous with the press-fitting allowance portion 14, and the end on the one side L1 is continuous with the small-diameter portion 16. That is, the protruding surface portion 15 is provided between the press-fitting allowance portion 14 and the small-diameter portion 16 on the one side L1 rather than the end on the other side L2 in the press-fitting portion 13 and protrudes inward of the main body 10.

[0026] The protruding surface portion 15 is formed with a predetermined angle θ1 with respect to the axis L. Note that the predetermined angle θ1 is an angle formed by the wall surface of the protruding surface portion 15 located on the upper side and the protruding surface portion 15 located on the lower side when extended to the one side L1 with each other in the cross-sectional view shown in FIG. 2(A), and can be set as appropriate. As shown in FIG. 3(A), the protruding surface portion 15 includes a pre-formed surface portion 15a formed in advance before press-fitting the valve seat member 20. That is, the protruding surface portion 15 is composed of the pre-formed surface portion 15a. Details of the formation of the protruding surface portion 15 will be described later.

[0027] The small-diameter portion 16 is an inner wall surface constituting one-side L1 portion of the press-fitting portion 13, and is formed in a cylindrical shape that is continuous with the protruding surface portion 15 and extends to the one side L1. As shown in Fig. 3(A), the inner diameter dimension α2 of the small-diameter portion 16 is set to be equal to or less than the inner diameter dimension α1 of the press-fitting allowance portion 14. As shown in Fig. 1, in the valve body 11, a caulking portion 17 that engages with the press-fitted valve seat member 20 is formed in the one-side L1 portion of the press-fitting portion 13. The caulking portion 17 is formed by caulking the one-side L1 portion of the valve body 11 from the radially outer side to the radially inner side, and engages with at least one-side L1 end portion of an annular recess 34 (to be described later) of the valve seat member 20. An inlet pipe 18 is continuous with the one-side L1 end portion of the valve body 11 formed in this way.

[0028] The inlet pipe 18 extends to the one side L1 and is formed in a cylindrical shape. The inlet pipe 18 includes a large-diameter inlet pipe 18a that is continuous with the one side L1 of the valve body 11, and a small-diameter inlet pipe 18b that is continuous with the one side L1 of the large-diameter inlet pipe 18a. The outer diameter of the small-diameter inlet pipe 18b is formed to be smaller than the outer diameter of the large-diameter inlet pipe 18a. On the other hand, an outlet pipe 19 is continuous with the other-side L2 end portion of the valve body 11. The outlet pipe 19 includes a small-diameter outlet pipe 19a that is continuous with the valve body 11, and a large-diameter outlet pipe 19b that is continuous with the other side L2 of the small-diameter outlet pipe 19a. The outer diameter and inner diameter of the large-diameter outlet pipe 19b are formed to be larger than the outer diameter and inner diameter of the small-diameter outlet pipe 19a. In the valve body 11 of the main body 10, the valve seat member 20 is press-fitted and accommodated from the other side L2 toward the one side L1.

[0029] The valve seat member 20 is formed in a cylindrical shape using a metal material such as brass. As shown in Fig. 2(B), the valve seat member 20 includes a cylindrical valve seat portion 30 extending in the direction of the axis L. At the center of the valve seat portion 30, a valve port 31 penetrating in the direction of the axis L is formed. The opening end portion on the other side L2 of the valve port 31 is expanded in the radially outward direction to form a stepped shape, and this stepped portion constitutes the valve seat 32. On the outer peripheral surface (outer surface) of the valve seat portion 30, a press-fitting portion 33 that slidably contacts (press-fits) the press-fitting portion 13 of the main body 10 is formed. The press-fitting portion 33 includes a flat portion 33a extending in the direction of the axis L and an inclined surface portion 33b that is continuous with the flat portion 33a and inclined with respect to the direction of the axis L. The flat portion 33a extends substantially parallel to the axis L. The inclined surface portion 33b (press-fitting portion 33) is formed with a predetermined angle θ2 with respect to the axis L.

[0030] The predetermined angle θ2 is an angle formed by a portion where the upper inclined surface portion 33b and the lower inclined surface portion 33b, which are located on the upper side and the lower side, respectively, in the cross-sectional view shown in Fig. 2(B), intersect when extended to one side L1 with respect to each other, and can be set as appropriate. The inclined surface portion 33b is in close contact with the protruding surface portion 15 in a state where the valve seat member 20 is press-fitted into the valve body 11. Then, as shown in Fig. 1, a seal portion S is formed by a close contact portion where the inclined surface portion 33b and the protruding surface portion 15 are in close contact. By forming the seal portion S, back leakage where fluid leaks to an unintended portion is prevented. Specifically, when the fluid flows in the reverse flow direction, it is prevented that the fluid leaks from between the press-fitting portion 33 of the valve seat member 20 and the press-fitting portion 13 of the valve body 11, except at the seating portion where the valve body 50 and the valve seat 32 are in contact. On one side L1 of the press-fitting portion 33, an annular recess 34 that is recessed radially inward is formed. The caulking portion 17 of the valve body 11 described above is engaged with the annular recess 34. Thereby, the displacement of the valve seat member 20 in the direction of the axis L, which is press-fitted into the valve body 11, is restricted, and the valve seat member 20 is prevented from coming out of the valve body 11. On the other side L2 of the press-fitting portion 33, a flange portion 35 that protrudes radially outward is formed. The flange portion 35 is formed over the entire circumference around the axis L.

[0031] The flange portion 35 is provided so as to be able to abut against one side L1 with respect to the boundary portion between the large-diameter portion 12 and the press-fitting portion 13 of the main body 10. When the flange portion 35 abuts against the boundary portion between the large-diameter portion 12 and the press-fitting portion 13, the displacement of the valve seat member 20 toward the one side L1 is restricted. On the other side L2 of the valve seat portion 30, a valve holder portion 40 is formed. The valve holder portion 40 is formed in a cylindrical shape that rises from the end portion on the other side L2 of the valve seat portion 30 toward the other side L2. The inside of the valve holder portion 40 constitutes a valve chamber 41, and a valve body 50 is accommodated in the valve chamber 41. The outer diameter of the valve holder portion 40 is set smaller than the inner diameter of the valve main body 11. Four communication holes 42 penetrating in the radial direction are formed in the peripheral wall surface of the valve holder portion 40. Thereby, the valve chamber 41 and the inside of the valve main body 11 communicate with each other. A valve stopper 43 is attached to the inner surface of the end portion on the other side L2 of the valve holder portion 40. The valve stopper 43 is formed in a substantially annular shape using a metal material such as stainless steel, and functions as a retaining ring that restricts the movement of the abutted valve body 50 toward the other side L2.

[0032] The valve body 50 accommodated in the valve holder portion 40 is formed in a cylindrical shape from a resin material. The valve body 50 is provided so as to be slidable in the axial direction L within the valve chamber 41, and opens and closes the valve port 31 by moving forward and backward in the axial direction L. As shown in FIG. 2(B), the valve body 50 includes a substantially cylindrical valve body main body 51. Four groove portions 52 extending in the axial direction L are formed on the outer surface of the valve body main body 51. Thereby, the cross-sectional shape of the cross-section intersecting the axial direction L of the valve body main body 51 is substantially cross-shaped. By forming the groove portions 52, only the outer periphery of the substantially cross-shaped shape slides on the inner periphery of the valve holder portion 40. Therefore, the movement resistance of the valve body 50 with respect to the valve holder portion 40 becomes small around the axis L, and the sliding movement of the valve body 50 is smoothly performed. A hollowed-out portion 53 that is hollowed out from the center of the end surface on the other side L2 toward the one side L1 without penetrating is formed at the center of the valve body main body 51. The hollowed-out portion 53 suppresses the generation of sink marks, bubbles, etc. during the resin molding of the valve body 50, and contributes to the weight reduction of the valve body 50. The end surface on the one side L1 of the valve body main body 51 constitutes a sealing surface 54 that closes the valve port 31 by abutting against the valve seat 32.

[0033] Next, the manufacturing of the check valve 1 will be described. First, a cylinder 10a extending in the axial direction L is formed using a metal material such as copper. Next, as shown in FIG. 4(A), a press-fitting allowance portion 14 as the press-fitting portion 13, a protruding surface portion 15, and a small-diameter portion 16 are formed on the cylinder 10a.

[0034] In this press-fitting portion 13, as shown in FIG. 3(A), the inner diameter dimension α2 of the small-diameter portion 16 is equal to or smaller than the inner diameter dimension α1 of the press-fitting portion 13. Also, as shown in FIG. 3(A), before the valve seat member 20 is press-fitted, the thickness dimension T1 (wall thickness) of the small-diameter portion 16 is larger than the thickness dimension T2 (wall thickness) of the press-fitting allowance portion 14. Further, the outer diameter dimension D1 of the small-diameter portion 16 is equal to the outer diameter dimension D2 of the press-fitting allowance portion 14. In this embodiment, the protruding surface portion 15 in the press-fitting portion 13 formed at this stage is particularly defined as the existing surface portion 15a. The existing surface portion 15a can be formed with various shapes and inclination angles. FIGS. 5(A) to (C) are schematic views showing variations of the existing surface portion 15a (protruding surface portion 15) of the main body 10 and the press-fitting portion 33 of the valve seat member 20. FIGS. 6(D) to (F) are schematic views showing variations other than those shown in FIGS. 5(A) to (C) in the existing surface portion 15a of the main body 10 and the press-fitting portion 33 of the valve seat member 20. As shown in FIG. 5(A), the existing surface portion 15a can be formed such that its predetermined angle θ1 is equal to the predetermined angle θ2 of the inclined surface portion 33b (press-fitting portion 33).

[0035] Also, as shown in FIG. 5(B), the existing face 15a can be formed such that its predetermined angle θ1 is larger than the predetermined angle θ2 of the inclined face 33b. Further, as shown in FIG. 5(C), the existing face 15a can be formed such that its predetermined angle θ1 is smaller than the predetermined angle θ2 of the inclined face 33b. Also, as shown in FIG. 6(D), the existing face 15a can be formed such that the predetermined angle θ1 is 90°. Further, as shown in FIG. 6(E), the existing face 15a can also be formed to have a curved R portion 14c at the end (edge portion) of the other side L2 and the end (edge portion) of the one side L1. Also, as shown in FIG. 6(F), the existing face 15a can also be formed to project radially inward such that the predetermined angle θ1 is 90°.

[0036] Next, as shown in FIG. 4(B), one side L1 portion of the cylinder 10a is processed to form an inlet pipe 18 including a large-diameter inlet pipe 18a and a small-diameter inlet pipe 18b. Then, as shown in FIG. 4(C), a valve seat member 20 is press-fitted from the end of the other side L2 of the cylinder 10a toward the one side L1. At this time, a seal portion S is formed as follows. Specifically, as shown in FIG. 7(A), when the valve seat portion 30 is pushed (press-fitted) into the cylinder 10a from the other side L2 to the one side L1 with the inclined face 33b of the valve seat portion 30 being on the other side L2 from the press-fitting allowance portion 14, as shown in FIG. 7(B), the valve seat portion 30 moves to the one side L1 and is press-fitted. Then, as shown in FIG. 7(B), the inclined face 33b of the press-fitting portion 33 comes into close contact with the existing face 15a (projecting face 15), and the seal portion S is constituted by the close contact portion. In this way, the press-fitting portion 33 of the valve seat member 20 is press-fitted into the press-fitting allowance portion 14, and the inclined face 33b constitutes the seal portion S.

[0037] In addition, when the protruding surface portion 15 (existing surface portion 15a) is formed in advance as in the present embodiment, the dimensional relationships of the respective portions of the press-fitting portion 13 before and after the press-fitting of the valve seat member 20 are as shown in FIGS. 8(A) and (B). FIG. 8(A) is a schematic diagram showing the dimensional relationships of the respective portions of the inner peripheral surface of the main body 10 before the press-fitting of the valve seat member 20 shown in FIG. 7(A), and FIG. 8(B) is a schematic diagram showing the dimensional relationships of the respective portions of the press-fitting portion 13 shown in FIG. 7(B) after the valve seat member 20 is press-fitted into the press-fitting portion 13. As shown in FIG. 8(A), before the press-fitting of the valve seat member 20, the relationship between the inner diameter dimension α1 of the press-fitting allowance portion 14, the inner diameter dimension α2 of one side portion 16a of the small diameter portion 16, and the inner diameter dimension α4 of the other side portion 16b of the small diameter portion 16 is such that the inner diameter dimension α1 > the inner diameter dimension α2 = the inner diameter dimension α4. On the other hand, as shown in FIG. 8(B), after the press-fitting of the valve seat member 20, the relationship between the inner diameter dimension α6 of the press-fitting allowance portion 14, the inner diameter dimension α2 of one side portion 16a of the small diameter portion 16, and the inner diameter dimension α4 of the other side portion 16b of the small diameter portion 16 is such that the inner diameter dimension α6 > the inner diameter dimension α2 = the inner diameter dimension α4.

[0038] That is, the magnitude relationship of the inner diameter dimensions of the press-fitting allowance portion 14, one side portion 16a of the small diameter portion 16, and the other side portion 16b of the small diameter portion 16 does not change before and after the press-fitting of the valve seat member 20. This is the same even when the relationship of the inner diameter dimensions of the press-fitting allowance portion 14, one side portion 16a of the small diameter portion 16, and the other side portion 16b of the small diameter portion 16 before the press-fitting of the valve seat member 20 is configured to be different from the relationship shown in FIG. 8(A). FIGS. 9(A) and (B) are schematic diagrams showing variations in the dimensional relationships of the respective portions of the press-fitting portion 13 before the press-fitting of the valve seat member 20. As shown in FIG. 9(A), before the press-fitting of the valve seat member 20, the relationship between the inner diameter dimension α1 of the press-fitting allowance portion 14, the inner diameter dimension α2 of one side portion 16a of the small diameter portion 16, and the inner diameter dimension α4 of the other side portion 16b of the small diameter portion 16 is such that the inner diameter dimension α2 < the inner diameter dimension α1 = the inner diameter dimension α4.

[0039] Also, as shown in Fig. 9(B), before the valve seat member 20 is press-fitted, the relationship between the inner diameter dimension α1 of the press-fitting allowance portion 14, the inner diameter dimension α2 of one-side portion 16a of the small-diameter portion 16, and the inner diameter dimension α4 of the other-side portion 16b of the small-diameter portion 16 is such that the inner diameter dimension α4 < the inner diameter dimension α2 < the inner diameter dimension α1. Thus, even in a configuration where the dimensional relationships of the respective parts are different from those of the above-described embodiments shown in Figs. 8(A) and (B), the magnitude relationship of the inner diameter dimensions of the press-fitting allowance portion 14, one-side portion 16a of the small-diameter portion 16, and the other-side portion 16b of the small-diameter portion 16 does not change before and after the press-fitting of the valve seat member 20, although not shown for after the press-fitting of the valve seat member 20.

[0040] Then, for the valve seat member 20 press-fitted into the valve body 11, the movement to one side L1 is restricted by the flange portion 35 abutting against the boundary portion between the large-diameter portion 12 and the press-fitting portion 13 of the valve body 11, and the press-fitting of the valve seat member 20 is completed by this abutment. After the press-fitting of the valve seat member 20 is completed, as shown in Fig. 4(C), a caulking portion 17 is formed in the valve body 11, and the valve seat member 20 is fixed to the valve body 11 by the engagement between the caulking portion 17 and the annular recess 34. Then, the other-side L2 portion of the cylinder 10a is machined to form an outlet pipe 19 including a small-diameter outlet pipe 19a and a large-diameter outlet pipe 19b, as shown in Fig. 1. Thereby, the manufacturing of the check valve 1 is completed.

[0041] Next, the details of the dimensional relationship around the press-fitted portion 13 will be described. Fig. 3(B) shows the dimensional relationship around the press-fitted portion 13 after the valve seat member 20 is press-fitted. In Fig. 3(B), the symbol X indicates the length in the axial direction L of the protruding surface portion 15 after the valve seat member 20 is press-fitted. Further, the symbol Y indicates the length in the radial direction orthogonal to the axial direction L of the protruding surface portion 15 after the valve seat member 20 is press-fitted. Also, the symbol α5 indicates the length in the axial direction L of the press-fitting allowance portion 14 after the valve seat member 20 is press-fitted. In the following description, the symbol X may be simply referred to as the length dimension X, the symbol Y may be simply referred to as the height dimension Y, and the symbol α5 may be simply referred to as the length dimension α5. Here, it is preferable that the height dimension Y of the protruding surface portion 15 is set to be smaller than the thickness dimension T2 (wall thickness) of the press-fitting allowance portion 14 after the valve seat member 20 is press-fitted. Specifically, it is preferably set to about 1 / 10 to 1 / 1 times, more preferably about 1 / 10 to 1 / 3 times, and even more preferably less than about 1 / 10 to 1 / 4 times the thickness dimension T2 of the press-fitting allowance portion 14 after the valve seat member 20 is press-fitted.

[0042] Here, by setting the height dimension Y of the protruding surface portion 15 to be smaller than the thickness dimension T2 of the press-fitting allowance portion 14 after press-fitting the valve seat member 20 to about 1 / 10 to 1 / 1 of the thickness dimension T2, or to 1 / 10 to 1 / 3 of the thickness dimension T2 or 1 / 10 to 1 / 4 of the thickness dimension T2, the following effects are obtained. For example, when the height dimension Y of the protruding surface portion 15 is set to be larger, such as 2 times (200%) or more of the thickness dimension T2 of the press-fitting allowance portion 14 after press-fitting the valve seat member 20, the protruding surface portion 15 functions as a positioning stopper for the valve seat member 20 during press-fitting, but is not suitable for the purpose of sealing the back leakage of the fluid. This is because the area of the inclined surface of the protruding surface portion 15 is large and the contact area between the protruding surface portion 15 and the press-fitting portion 33 becomes large, so that the close contact load generated between the protruding surface portion 15 and the press-fitting portion 33 is dispersed. However, in the present invention, the height dimension Y of the protruding surface portion 15 is smaller than the thickness dimension T2 of the press-fitting allowance portion 14 after press-fitting the valve seat member 20 by about 1 / 10 to 1 / 1 times (10 to 100%). Because of such a small protruding surface portion 15, the contact area between the press-fitting portion 33 of the valve seat member 20 and the protruding surface portion 15 becomes small, so that the close contact load is not dispersed as described above, and the crimping seal effect between the protruding surface portion 15 and the press-fitting portion 33 becomes high, and the seal performance can be improved. Further, when the height dimension Y is set to about 1 / 10 to 1 / 3 times (10 to 33%) of the thickness dimension T2, the contact area between the protruding surface portion 15 and the press-fitting portion 33 becomes smaller, so that the above-described crimping seal effect becomes higher and the seal performance becomes higher. In particular, when the height dimension Y is set to about 1 / 10 to 1 / 4 times (10 to 25%) of the thickness dimension T2, the contact area between the protruding surface portion 15 and the press-fitting portion 33 becomes even smaller, so that the crimping seal effect becomes even higher and the seal performance becomes higher.

[0043] Further, the height dimension Y of the protruding surface portion 15 is preferably set to be about 4% to 10% of the length dimension α5 of the press-fitting allowance portion 14, and more preferably set to about 5%. Further, the length dimension X of the protruding surface portion 15 is preferably set to be about 20% to 50% of the length dimension α5 of the press-fitting allowance portion 14. By configuring in this way, since the protruding surface portion 15 having sufficient length dimension X and height dimension Y with respect to the length dimension α5 of the press-fitting allowance portion 14 can be provided, when the seal portion S is formed on the protruding surface portion 15, while reducing the above-mentioned close contact area, a sufficient seal area can be ensured, and the seal performance can be significantly improved.

[0044] The check valve 1 configured in this way is used in various postures. For example, when the axial direction L shown in FIG. 1 is the vertical direction, that is, when it is used in the vertically placed state, it operates as follows. First, when the valve body 50 is seated on the valve seat 32 by its own weight and is in the position shown in FIG. 1 (hereinafter, also referred to as the valve closed position), fluid flows in the forward flow direction from the inlet pipe 18 toward the outlet pipe 19. Then, the valve body 50 pushed by the fluid flowing out from the valve port 31 is separated from the valve seat 32, the valve port 31 opens, and it becomes the valve open state and moves to the position where it abuts against the valve stopper 43. And when the flow of the fluid in the forward flow direction stops, the valve body 50 falls by its own weight and again seats on the valve seat 32, the valve port 31 closes, and it becomes the valve closed state. Further, when the check valve 1 is used in the horizontally placed state or the vertically placed state with the up and down reversed, it operates as follows. First, when the valve body 50 is in the valve closed position, the pressure on the outlet pipe 19 side is set higher than that on the inlet pipe 18 side, and the fluid flows in the reverse flow direction due to the differential pressure at this time.

[0045] As a result, the valve body 50 is pressed against the valve seat 32 and the seated state is maintained. In this state, when the pressure in the inlet pipe 18 increases and fluid flows in the forward flow direction from the inlet pipe 18 side to the outlet pipe 19 side, the valve body 50 pushed by the fluid flowing out from the valve port 31 separates from the valve seat 32. Then, when the forward flow of the fluid stops and the pressure on the outlet pipe 19 side increases again compared to the inlet pipe 18 side, the fluid flows in the reverse flow direction due to the differential pressure. As a result, the valve body 50 seats on the valve seat 32 again. When the fluid flows in this way, in this embodiment, since the seal portion S is provided, back leakage where fluid leaks out to unintended portions between the main body 10 and the valve seat member 20 is prevented. Specifically, for example, as described above, when the fluid flows in the reverse flow direction, it is prevented that fluid leaks from between the press-fitting portion 33 of the valve seat member 20 and the press-fitted portion 13 of the main body 10, other than the seating portion where the valve body 50 and the valve seat 32 contact. In addition, in the state where the valve body 50 is seated on the valve seat 32, since the valve body 50 is pressed against the valve seat 32, a pressure load is applied to the valve seat member 20 in the valve closing direction. Therefore, the inclined surface portion 33b constituting the seal portion S is pressed against the protruding surface portion 15, and the inclined surface portion 33b and the protruding surface portion 15 are more closely adhered, further improving the sealing performance.

[0046] Here, the dimensional relationships of the valve body 11 after the valve seat member 20 is press-fitted will be described below with reference to FIG. 3(B). As shown in FIG. 3(B), the thickness dimension T1 of the small-diameter portion 16 is larger than the thickness dimension T2 of the press-fitting allowance portion 14 (that is, thickness dimension T1 > thickness dimension T2). Also, the outer diameter dimension D1 of the small-diameter portion 16 is equal to the outer diameter dimension D2 of the press-fitting allowance portion 14 (that is, outer diameter dimension D1 = outer diameter dimension D2). Note that the outer diameter dimension D2 may be slightly larger than the outer diameter dimension D1, and thereby, a minute inclination (taper) that smoothly connects without a step portion from the outer peripheral surface of the small-diameter portion 16 to the outer peripheral surface of the press-fitting allowance portion 14 may be formed.

[0047] Here, in the check valve described in Patent Document 1, as shown in FIG. 2(b) of Patent Document 1, the thickness dimension of the portion corresponding to the small-diameter portion 16 of the present embodiment and the thickness dimension of the portion corresponding to the press-fitting allowance portion 14 are the same. When the valve seat member is press-fitted, the wall thickness of the valve body housing portion does not change and the whole diameter is expanded. Therefore, the dimension corresponding to the outer diameter dimension D2 of the present embodiment (the outer diameter dimension of the portion corresponding to the press-fitting allowance portion 14 of the present embodiment) is larger than the dimension corresponding to the outer diameter dimension D1 of the present embodiment (the outer diameter dimension of the portion corresponding to the small-diameter portion 16 of the present embodiment), which is different from the present embodiment. Also, in the check valve described in Patent Document 1, a step portion is formed on the outer peripheral surface of the valve body housing portion before the valve seat member is press-fitted, which is different from the present embodiment.

[0048] Thus, the reason why the relationship between the thickness dimensions and the relationship between the outer diameter dimensions of the portion corresponding to the small-diameter portion 16 and the portion corresponding to the press-fitting allowance portion 14 are different from those of the present embodiment is that the check valve described in Patent Document 1 controls a general fluid in a refrigeration cycle system and does not control ultra-high pressure fluid pressing or the like as in the present embodiment. That is, the required pressure resistance of the check valve described in Patent Document 1 is lower than that of the present embodiment. For this reason, the wall thickness of the valve body housing portion of the check valve described in Patent Document 1 is, for example, about 1 / 2 as thin as that of the valve body 11 of the present embodiment, and the valve body housing portion is easily deformed by the press-fitting of the valve seat member. Therefore, as described above, the thickness dimension of the portion corresponding to the small-diameter portion 16 and the thickness dimension of the portion corresponding to the press-fitting allowance portion 14 are expanded while being equal, and the dimension corresponding to the outer diameter dimension D2 is larger than the dimension corresponding to the outer diameter dimension D1.

[0049] Here, in the present embodiment, since the thickness dimension T1 of the small-diameter portion 16 is larger than the thickness dimension T2 of the press-fitting allowance portion 14 (thickness dimension T1 > thickness dimension T2), the following effects can be achieved. Since the thickness dimension T1 of the small-diameter portion 16 becomes partially smaller due to the formation of the caulked portion 17 described above, if the thickness dimension T1 = thickness dimension T2, the pressure resistance of the valve body 11 may locally decrease at the caulked portion 17. However, in the present embodiment, since the thickness dimension T1 of the small-diameter portion 16 is originally larger than the thickness dimension T2 of the press-fitting allowance portion 14, even if the caulked portion 17 is formed, the pressure resistance of the valve body 11 does not locally decrease. Therefore, compared with the configuration in which the thickness dimension of the portion corresponding to the small-diameter portion 16 and the thickness dimension of the portion corresponding to the press-fitting allowance portion 14 are the same, as in the check valve described in Patent Document 1 above, it is easy to prevent cracks and the like of the valve body 11 caused by a decrease in pressure resistance. And by preventing such cracks, the risk of external leakage of the fluid can be reduced, and the reliability of the check valve 1 for ultra-high-pressure fluid can be improved.

[0050] Also, in the present embodiment, since the outer diameter dimension D1 of the small-diameter portion 16 is equal to the outer diameter dimension D2 of the press-fitting allowance portion 14, the following effects can be achieved. Since the outer diameter dimension D1 of the small-diameter portion 16 is equal to the outer diameter dimension D2 of the press-fitting allowance portion 14, no step or the like due to the difference between the outer diameter dimension D1 and the outer diameter dimension D2 occurs in the valve body 11, and it is difficult to form a portion where stress concentration occurs, such as the boundary portion of the step. Therefore, it is easy to prevent stress corrosion cracking due to stress concentration. This effect is particularly remarkable compared with the check valve described in Patent Document 1 in which a step occurs on the outer peripheral surface of the valve body housing portion because the dimension corresponding to the outer diameter dimension D2 is larger than the dimension corresponding to the outer diameter dimension D1. That is, in the present embodiment, compared with the check valve described in Patent Document 1, it is easy to prevent stress corrosion cracking of the valve body 11, and the reliability of the check valve 1 for ultra-high-pressure fluid can be improved.

[0051] Incidentally, as described above, in this embodiment, the above-described effects are the same even when the outer diameter dimension D2 is slightly larger than the outer diameter dimension D1 and there is a minute inclination (taper) that smoothly connects from the outer peripheral surface of the small-diameter portion 16 to the outer peripheral surface of the press-fitting portion 14 without a step portion. With this configuration, even if there is a difference between the outer diameter dimension D1 and the outer diameter dimension D2, a stress concentration portion such as the boundary portion of the step is not formed, and stress corrosion cracking of the valve body 11 is prevented.

[0052] Further, in this embodiment, as described above, the thickness dimension T1 > the thickness dimension T2, and the outer diameter dimension D1 = the outer diameter dimension D2. According to this configuration, since the protruding surface portion 15 is formed on the valve body 11 due to the thickness dimension T1 > the thickness dimension T2, the seal portion S can be configured at the contact portion between the protruding surface portion 15 and the press-fitting portion 33, and back leakage of the fluid can be prevented. Further, since the outer diameter dimension D1 = the outer diameter dimension D2, it is difficult to form a stress concentration portion such as the boundary portion of the step on the valve body 11. Therefore, stress corrosion cracking due to stress concentration can be prevented.

[0053] As shown in FIG. 10, this check valve 1 is installed and used in the middle of the fluid flow path in the refrigeration cycle system 100. The refrigeration cycle system 100 is used, for example, in an air conditioner such as a commercial air conditioner. This refrigeration cycle system 100 is connected by piping with an indoor heat exchanger 101, an outdoor heat exchanger 102, an expansion valve 103, a four-way valve 104, and three compressors 105 connected in parallel. The check valve 1 is connected between the discharge (high-pressure output) side of each compressor 105 and the four-way valve 104 in order to prevent backflow of the fluid to each compressor 105, with the compressor 105 on the inlet pipe 18 side and the four-way valve 104 on the outlet pipe 19 side. During the cooling operation, as indicated by the solid-line arrow D101, after the fluid is compressed by the compressor 105, it reaches the outdoor heat exchanger 102 through the check valve 1 and the four-way valve 104. Then, after the fluid releases heat in the outdoor heat exchanger 102, it flows through the expansion valve 103 to the indoor heat exchanger 101, absorbs heat in the indoor heat exchanger 101, and returns to the compressor 105 via the four-way valve 104.

[0054] During the heating operation, as indicated by the dotted arrow D102, after the fluid is compressed by the compressor 105, it reaches the indoor heat exchanger 101 through the check valve 1 and the four-way valve 104. Then, after the fluid releases heat in the indoor heat exchanger 101, it flows through the expansion valve 103 to the outdoor heat exchanger 102, absorbs heat in the outdoor heat exchanger 102, and then returns to the compressor 105 via the four-way valve 104. The refrigeration cycle system 100 repeats these cycles to perform indoor cooling or heating. Here, for example, under conditions where the cooling load is large, since the three compressors 105 are operated simultaneously, each of the three check valves 1 is fully open. Also, under conditions where the cooling load is small, since only the operation of one compressor 105 is sufficient, the other two compressors 105 do not operate. At this time, the pressure of the outlet pipe 19 of the two check valves 1 becomes higher than the pressure on the inlet pipe 18 side, causing backflow from the outlet pipe 19 side, and the two check valves 1 are in a closed state.

[0055] As described above, according to the above-described embodiment, by providing the protruding surface portion 15 in the press-fitting portion 13 on the inner surface of the main body 10 and forming the seal portion S by the close contact portion between the press-fitting portion 33 of the valve seat member 20 and the protruding surface portion 15, it is possible to reliably prevent the back leakage in which the fluid flowing in the main body 10 leaks out to an unintended portion by the seal portion S. Thereby, the sealing performance of the check valve 1 (valve device) can be improved. For this reason, even when an ultra-high pressure fluid or the like is used for the fluid to be controlled by the check valve 1, a high sealing performance can be maintained as compared with a structure in which the valve seat member is simply press-fitted into the valve body accommodating portion as in the conventional valve device. Therefore, it is possible to provide the check valve 1 that improves the sealing performance.

[0056] Further, in the present embodiment, by configuring the protruding surface portion 15 by the existing surface portion 15a formed before press-fitting the valve seat member 20, the press-fitting portion 33 of the valve seat member 20 is brought into close contact with the existing surface portion 15a formed in advance on the main body 10 to form the seal portion S. Therefore, even when an ultra-high pressure fluid is used as the control target of the check valve 1, fluid back leakage can be prevented as compared with a conventional valve device that does not have the existing surface portion 15a that comes into close contact with the press-fitting portion 33 of the valve seat member 20. Also, the sealing property of the check valve 1 can be maintained at a high level.

[0057] Further, according to the present embodiment, the existing surface portion 15a (projecting surface portion 15) is formed with a predetermined angle θ1 with respect to the axis L. Therefore, the projecting surface portion 15 can be formed into various shapes, such as a tapered shape inclined with respect to the axis L of the main body 10 or a right-angled shape orthogonal to the axis L of the main body 10. Further, since the existing surface portion 15a can be set at a predetermined angle θ1 with respect to the axis L, by changing the angle, the close state between the press-fitting portion 33 and the projecting surface portion 15 can be appropriately changed according to the conditions such as the materials of the main body 10 and the valve seat member 20. Therefore, the sealing performance of the check valve 1 can be maintained high. Note that the shape of the projecting surface portion 15 is not limited to the tapered shape or the right-angled shape as described above. For example, instead of the inclined surface of the tapered portion in the tapered shape, a convex R shape connecting both ends of the tapered portion, a concave R shape, or the like may be used.

[0058] Further, according to the present embodiment, the main body 10 and the valve seat member 20 are provided in a cylindrical shape, and the press-fitting portion 13 is provided with a press-fitting allowance portion 14, a projecting surface portion 15, and a small-diameter portion 16. The press-fitting allowance portion 14 is set such that the inner diameter dimension α1 before press-fitting the valve seat member 20 is smaller than the outer diameter dimension β1 of the press-fitting portion 33 in the valve seat member 20 before press-fitting. The small-diameter portion 16 has an inner diameter dimension α2 that is equal to or smaller than the inner diameter dimension α1 of the press-fitting allowance portion 14. The end portion on the other side L2 of the projecting surface portion 15 is continuous with the press-fitting allowance portion 14, and the end portion on one side L1 of the projecting surface portion 15 is continuous with the small-diameter portion 16. According to such a configuration, the valve seat member 20 can be reliably press-fitted into the main body 10, and the seal portion S can be reliably formed between the projecting surface portion 15 and the press-fitting portion 33.

[0059] Further, according to the present embodiment, when the caulking portion 17 is formed on the valve body 11, the thickness dimension T1 of the small-diameter portion 16 is partially reduced at the portion of the caulking portion 17. However, since the original thickness dimension T1 of the small-diameter portion 16 is larger than the thickness dimension T2 of the press-fitting allowance portion 14, the pressure resistance of the valve body 11 (main body 10) does not locally decrease. Therefore, it is easy to prevent cracks in the valve body 11. By preventing such cracks, the risk of external leakage of fluid can be reduced, and the reliability of the check valve 1 against ultra-high pressure fluid can be improved.

[0060] Further, according to the present embodiment, since the outer diameter dimension D1 of the small-diameter portion 16 is equal to the outer diameter dimension D2 of the press-fitting portion 14, no step or the like due to the outer diameter dimension difference occurs in the main body 10. Therefore, in the valve body 11 (main body 10), it is difficult to form a portion where stress concentration occurs, such as a boundary portion of a step. For this reason, stress corrosion cracking due to stress concentration can be easily prevented, and the reliability of the check valve 1 against ultra-high pressure fluid can be improved.

[0061] Also, according to the present embodiment, since the refrigeration cycle system 100 can be configured using the check valve 1 that improves the sealing performance, the energy efficiency of the refrigeration cycle system 100 is improved.

[0062] Note that the embodiments described above merely show typical forms of the present invention, and the present invention is not limited thereto. That is, various modifications can be made without departing from the gist of the present invention. As long as the configuration of the check valve 1 of the present invention is provided even by such modifications, it is of course included in the scope of the present invention. For example, in the description of the present embodiment, the inlet pipe 18 is arranged on one side L1 of the valve body 11, and the outlet pipe 19 is arranged on the other side L2, but this arrangement may be reversed, that is, the inlet pipe 18 may be arranged on the other side L2 of the valve body 11, and the outlet pipe 19 may be arranged on one side L1 of the valve body 11.

[0063] Also, the check valve 1 is merely an example of the valve device in the present invention, and of course, the present invention can be applied to other valve devices. For example, a slide type switching valve, an electric valve, a solenoid valve including a plunger and an electromagnetic coil, which have a plurality of valve ports in the valve body and control the flow of fluid flowing through the valve ports, or a pressure regulating valve that drives a pressure-sensitive member connected to a valve member in response to pressure fluctuations, a manual on-off valve provided with an operating portion for moving a valve body forward and backward, etc. The present invention may be applied to these. Also, in that case, the valve device does not necessarily have to be used in the refrigeration cycle system 100, and can be used in various devices for controlling fluid.

[0064] In the above-described embodiment, the outer diameter dimension D1 of the small-diameter portion 16 is set to be equal to the outer diameter dimension D2 of the press-fitting allowance portion 14. Here, the outer diameter dimension D1 of the small-diameter portion 16 being equal to the outer diameter dimension D2 of the press-fitting allowance portion 14 means that the outer diameter dimension D2 of the press-fitting allowance portion 14 is included in the range of 0% to +3% with respect to the outer diameter dimension D1 of the small-diameter portion 16.

[0065] Next, a second embodiment will be described. FIG. 11 is a cross-sectional view of the check valve 1A according to the second embodiment cut along the axial direction L. FIG. 12 is a cross-sectional view of the valve seat member 20A according to the second embodiment cut along the axial direction L. FIG. 13 is an enlarged view of the main part of the check valve 1A shown in FIG. 11. As shown in FIG. 11, in the check valve 1A according to the second embodiment, the caulking portion 17 described above is omitted in the one-side L1 portion of the press-fitted portion 13A. Further, as shown in FIG. 12, in the check valve 1A, an annular recess 34 with which the caulking portion 17 described above engages is omitted in the one-side L1 portion of the press-fitting portion 33A of the valve seat member 20A. In the check valve 1A configured in this way, as shown in FIG. 13, a press-fitting allowance portion 14A is formed in the press-fitted portion 13A. The press-fitting allowance portion 14A corresponds to the press-fitting allowance portion 14 of the above-described embodiment. Further, the press-fitting allowance portion 14A constitutes a preformed surface portion formed before the valve seat member 20A is press-fitted.

[0066] The press-fitting allowance portion 14A as the existing surface portion of the second embodiment is formed by performing plastic working on the inner surface of the main body 10A. By this plastic working, the thickness dimension T2 of the press-fitting allowance portion 14A is smaller than the thickness dimension T1 of the small-diameter portion 16A. By forming the press-fitting allowance portion 14A having a thickness dimension T2 smaller than the thickness dimension T1 of the small-diameter portion 16A by plastic working, the hardness of the press-fitting allowance portion 14A can be made higher than the hardness of the small-diameter portion 16A, and the press-fitting allowance portion 14A can be made difficult to deform. Therefore, even if the structure inside the main body 10A undergoes repeated changes such as expansion or contraction due to changes in pressure or temperature, the holding strength of the main body 10A with respect to the press-fitting portion 33A of the valve seat member 20A can be maintained high, and the sealing performance of the seal portion S can be stabilized. And according to this configuration, even if the caulking portion 17 is not provided in the main body 10A, the holding force of the main body 10A with respect to the press-fitting portion 33A of the valve seat member 20A can be maintained. Therefore, for example, the pull-out strength of the valve seat member 20A can be improved against the repeated contact (collision) of the valve body 50 with the valve stopper 43 when the valve is opened. Thus, the press-fitting allowance portion 14A constitutes a holding force strengthening portion that strengthens the holding force of the press-fitted portion 13A.

[0067] Note that the plastic working can be appropriately selected as long as it is a working that can obtain work hardening. For example, although not shown in the drawings, a cylinder extending in the axial direction L is formed using a metal material that will constitute the main body 10A, a rod-shaped jig or the like is inserted inside the cylinder, and a part of the outer wall of the cylinder is pressed from the radially outer side toward the radially inner side by spinning or the like. Thereby, the outer peripheral shape of the rod-shaped jig may be transferred to the inner peripheral surface of the cylinder to form the press-fitting allowance portion 14A or the like.

[0068] Next, the third embodiment will be described. FIG. 14 is a cross-sectional view of the check valve 1B according to the third embodiment cut along the axial direction of the axis L. FIG. 15(A) is a cross-sectional view of the valve seat member 20B according to the third embodiment cut along the axial direction of the axis L, and FIG. 15(B) is an enlarged cross-sectional view of the region I in FIG. 14. FIGS. 16(A) to (D) are side views of the main bodies 10A, 10B, and 10C for showing variations of the caulking portions 17B and 17C. FIG. 17(A) is an enlarged view of the region II in FIG. 14, FIG. 17(B) is a cross-sectional view taken along the line A-A in FIG. 15, and FIG. 17(C) is a cross-sectional view showing another embodiment of the oil introduction portion 37. As shown in FIG. 14, the check valve 1B of the third embodiment includes a large-diameter portion 12B and a press-fitting portion 13B on the inner peripheral surface of the main body 10B. The press-fitting portion 13B includes a press-fitting allowance portion 14B, a protruding surface portion 15B, and a small-diameter portion 16B from the other side L2 toward the one side L1.

[0069] These large-diameter portion 12B, press-fitting portion 13B, press-fitting allowance portion 14B, protruding surface portion 15B, and small-diameter portion 16B correspond to the large-diameter portion 12, press-fitting portion 13, press-fitting allowance portion 14, protruding surface portion 15, and small-diameter portion 16 described above. As shown in FIG. 14, in the main body 10B, a caulking portion 17B that engages with the press-fitted valve seat member 20B is formed in the one-side L1 portion of the press-fitting portion 13B. The caulking portion 17B is formed by caulking the one-side L1 portion of the main body 10B from the radially outer side to the radially inner side. As shown in FIG. 15(B), the caulking portion 17B has a shape that protrudes in an arc shape around the intersection of a virtual line c1 along the outer peripheral surface of the main body 10B and a virtual line c2 perpendicular to this virtual line c1, and its tip portion constitutes a caulking convex portion 17B1. This caulking convex portion 17B1 bites into and engages with a corner portion 34a of the valve seat member 20B described later. In this embodiment, the outer peripheral surface of the main body 10B and the virtual line c1 overlap, but since the position of the virtual line c1 changes depending on the shape of the caulking portion 17, the outer peripheral surface of the main body 10B and the virtual line c1 do not have to overlap.

[0070] Next, the valve seat member 20B will be described. As shown in Fig. 15(A), an annular recess 34B that is recessed inward is formed on one side L1 of the press-fitting portion 33B in the valve seat member 20B. One end of the annular recess 34B on the side L1 constitutes a corner portion 34a having a surface 34a1 facing the other end of the valve seat member 20B on the side L2. As shown in Fig. 15(B), when the caulking portion 17B is formed after the valve seat member 20B is press-fitted into the main body 10B, a part of the corner portion 34a is bitten into and engaged by the caulking projection 17B1. Thereby, compared with a structure in which the caulking projection 17B1 simply abuts against the corner portion 34a, the valve seat member 20B is less likely to loosen with respect to the main body 10B. Therefore, the holding force of the valve seat member 20B by the main body 10B can be further improved, and the pull-out strength of the valve seat member 20B can be further improved.

[0071] Also, at this time, the valve seat member 20B and the main body 10B will approach each other in the biting-in direction. As a result, the inclined surface portion 33b of the press-fitting portion 33B constituting the seal portion S will be closer to the protruding surface portion 15B of the main body 10B, and the surface pressure of the seal portion S can be increased. Therefore, the sealing performance of the seal portion S is further improved. Accordingly, an operating fluid leakage prevention portion that suppresses fluid leakage is constituted by the biting-in portion, and back leakage of the fluid can be suppressed. In Fig. 15(B), the reference sign V indicates the biting-in amount of the caulking projection 17B1 into the corner portion 34a. This biting-in amount is indicated by the distance between a straight line C1 that is perpendicular to a virtual line c3 drawn from the intersection of the above-described virtual lines c1 and c2 toward the apex of the corner portion 34a and a straight line C2 that is parallel to the straight line C1 and in contact with the caulking projection 17B1. This biting-in amount V is preferably about 1% to 20% of the thickness dimension T3 of the small-diameter portion 16B. By doing so, while maintaining the sealing performance that can appropriately prevent back leakage by the biting-in portion (operating fluid leakage prevention portion) into the corner portion 34a, deformation of the valve seat member 20B during biting-in into the corner portion 34a can be suppressed.

[0072] Also, in the direction of the axis L, let the dimension from the end of one side L1 of the valve seat member 20B to the corner 34a be dimension α7. Further, let the dimension from the corner 34a to the end of the other side L2 of the caulking convex portion 17B1 (the boundary portion between the caulking convex portion 17B1 and the small-diameter portion 16B) be dimension α8. In this case, it is preferable that dimension α7 is 0.5 times or more of dimension α8. Thereby, in the valve seat member 20B, the dimension in the direction of the axis L from the portion where the corner 34a is formed to the end of one side L1 is sufficiently ensured, and the strength of the one side L1 portion of the valve seat member 20B can be ensured. For this reason, since deformation of the one side L1 portion of the valve seat member 20B can be suppressed, when the caulking convex portion 17B1 is engaged with the corner 34a, the pull-out strength of the valve seat member 20B can be further improved.

[0073] Note that the caulking portion 17B that bites into the corner 34a may be formed over the entire circumference around the axis L as shown in FIG. 16(B) by performing roll caulking on the outer circumference of the main body 10A where the caulking portion 17 shown in FIG. 16(A) is not formed. However, as shown in FIG. 16(C), it is more preferable to form it pinpoint at the location corresponding to the small-diameter portion 16B by performing punch caulking. In this case, the caulking convex portion 17B1 is composed of the tip of the caulking portion 17B that is formed by punch caulking and protrudes inward of the main body 10B. According to this, by forming the caulking portion 17B by punch caulking, the stress generated in the caulking portion 17B can be reduced as compared with a structure in which so-called roll caulking is performed to perform caulking over the entire circumference of the main body 10B.

[0074] For this reason, cracking of the main body 10B and external leakage of fluid due to the cracking can be suppressed. Note that the caulking portion 17B formed by punch caulking can also improve the holding force of the valve seat member 20B by forming it at one location. However, from the viewpoint of ensuring the strength balance over the entire circumference of the main body 10B, it is more preferable to form it at equal intervals, for example, at four locations or eight locations in the circumferential direction of the main body 10B.

[0075] Then, as shown in FIG. 15(A), a flange portion 35B that protrudes radially outward toward the inner surface of the main body 10B is formed at the end of the other side L2 in the press-fitting portion 33B of the valve seat member 20B. As shown in FIG. 17(A), the flange portion 35B abuts against the boundary portion 10B1 between the large-diameter portion 12B and the press-fitting allowance portion 14B of the inner surface of the main body 10B in a state where the valve seat member 20B is press-fitted into the main body 10B. At this time, a space surrounded by the flange portion 35B, the press-fitting portion 33B (the portion other than the flange portion 35B in the valve seat member 20B), and the press-fitting allowance portion 14B of the main body 10B is formed between the main body 10B and the valve seat member 20B. This space constitutes an oil reservoir portion 36 capable of storing the oil 60 contained in the fluid flowing into the check valve 1B. Then, as shown in FIG. 17(B), an oil introduction portion 37 that communicates the oil reservoir portion 36 with the inside of the main body 10B is formed in the flange portion 35B. The oil introduction portion 37 is constituted by a gap between the valve seat member 20B and the inner surface of the main body 10B generated by linearly cutting out a part of the outer peripheral surface of the annular flange portion 35B.

[0076] In the third embodiment, the oil introduction portion 37 is formed by notching, but the structure of the oil introduction portion 37 is not limited to this. As shown in FIG. 17(C), a groove 38 that recesses inward may be formed in a part of the outer peripheral surface of the annular flange portion 35B and penetrated in the axial direction L to be used as the oil introduction portion. In such a configuration, the oil 60 contained in the fluid flowing in the main body 10B enters the oil reservoir portion 36 through the oil introduction portion 37 and is stored in the oil reservoir portion 36. The stored oil 60 is supplied between the valve seat member 20B and the main body 10B by capillary action. Therefore, for example, if there is a minute gap or scratch between the press-fitting allowance portion 14B of the main body 10B and the press-fitting portion 33B of the valve seat member 20B, the oil 60 supplied to the gap or scratch can more reliably suppress the back leakage of the fluid. That is, the oil reservoir portion 36 and the oil introduction portion 37 constitute a working fluid leakage prevention portion that suppresses the leakage of the fluid, similar to the biting portion into the corner portion 34a described above.

[0077] Also, as shown in Fig. 17(A), the oil 60 stored in the oil reservoir portion 36 is difficult to move to the other side L2 by the flange contact portion 35B1 where the flange portion 35B contacts the main body 10B. Therefore, compared with a configuration in which a gap is simply provided between the valve seat member 20B and the main body 10B to form an oil reservoir portion, the following can be suppressed. That is, it is possible to prevent the so-called ejector effect in which the oil 60 is involved in the fluid flow around the oil reservoir portion 36 and the oil 60 is sucked out from the oil reservoir portion 36.

[0078] Next, the fourth embodiment will be described. Fig. 18 is a cross-sectional view of the check valve 1C according to the fourth embodiment cut along the axial direction of the axis L. Fig. 19 is an enlarged view of the region III in Fig. 18. In the check valve 1C, a caulking portion 17C is formed in one side L1 portion of the large-diameter portion 12C in the main body 10C. This caulking portion 17C is preferably formed at a pinpoint by performing punch caulking on the outer periphery of the main body 10A without the caulking portion 17C shown in Fig. 16(A) as shown in Fig. 16(D). As shown in Fig. 19, the tip of the caulking portion 17C constitutes a caulking convex portion 17C1. The caulking portion 17C corresponds to the above-described caulking portion 17B, and the caulking convex portion 17C1 corresponds to the above-described caulking convex portion 17B1. And in the check valve 1C, the outer peripheral edge of the flange portion 35C of the valve seat member 20C shown in Fig. 19 constitutes a corner portion 35C1 having a surface 39 facing the other side L2 end of the valve seat member 20C. The caulking convex portion 17C1 bites into and engages with the corner portion 35C1.

[0079] In FIG. 19, reference numeral V2 indicates the amount of penetration into the corner portion 35C1 of the caulking projection 17C1. This amount of penetration is defined by the distance between a virtual line C3 drawn from the intersection of a virtual line c1 along the outer peripheral surface of the main body 10C and a virtual line c2 perpendicular to the virtual line c1 to the apex of the corner portion 35C1, and a straight line C4 that is parallel to the straight line C3 and in contact with the caulking projection 17C1. It is preferable that this amount of penetration V2 be approximately 1% to 20% of the thickness dimension T3 of the large-diameter portion 12C. By doing so, while maintaining the sealing performance that can appropriately prevent back leakage by the penetration portion (working fluid leakage prevention portion) into the corner portion 35C1 of the caulking projection 17C1, it is possible to suppress deformation of the valve seat member 20C during penetration into the corner portion 35C1 and improve the pull-out strength of the valve seat member 20C.

[0080] Further, according to the fourth embodiment, since the working fluid leakage prevention portion can be configured by causing the caulking projection 17C1 to penetrate into the corner portion 35C1 of the flange portion 35C in the valve seat member 20C, it is not necessary to form the corner portion 34a of the annular recess 34B, and the annular recess 34B can be omitted. For this reason, the dimension of the valve seat member 20C in the axial direction of the axis L can be made smaller compared to the structure for forming the annular recess 34B. As a result, the check valve 1C can also be miniaturized, and overall cost reduction can be achieved.

Explanation of Reference Numerals

[0081] L1 One side L2 The other side S Sealing portion 1 Check valve (valve device) 10 Main body 13 Press-fitted portion 15 Protruding surface portion 20 Valve seat member 31 Valve port 33 Pressing portion 50 Valve body

Claims

1. A valve device comprising a cylindrical body extending from one side to the other side for flowing a fluid, a valve seat member press-fitted into the body, and a valve body for opening and closing a valve port provided in the valve seat member, a press-fitting portion provided on an outer surface of the valve seat member, and a press-fitted portion provided on an inner surface of the body, the press-fitting portion being slidably contacted from the other side to the one side, wherein a protruding surface portion protruding inward of the body is provided on the one side rather than the other side end portion in the press-fitted portion, and a seal portion for stopping leakage of the fluid is formed by a close contact portion between the press-fitting portion and the protruding surface portion.

2. The valve device according to claim 1, wherein the protruding surface portion is composed of a preformed surface portion formed before press-fitting the valve seat member.

3. The valve device according to claim 1, wherein the protruding surface portion is formed with a predetermined angle with respect to an axis of the body extending from the one side to the other side.

4. The body and the valve seat member are provided in a cylindrical shape, the press-fitted portion includes a press-fitting allowance portion provided on the other side, a small-diameter portion provided on the one side, and the protruding surface portion provided between the press-fitting allowance portion and the small-diameter portion, the press-fitting allowance portion has an inner diameter dimension before press-fitting the valve seat member smaller than an outer diameter dimension of the press-fitting portion in the valve seat member before press-fitting, the small-diameter portion has an inner diameter dimension equal to or less than an inner diameter dimension of the press-fitting allowance portion, and an end portion on the other side of the protruding surface portion is continuous with the press-fitting allowance portion, and an end portion on the one side of the protruding surface portion is continuous with the small-diameter portion.

5. A large-diameter portion having a larger inner diameter than the press-fitting allowance portion is provided on the other side of the press-fitting allowance portion, a flange portion protruding toward an inner surface of the body and contacting a boundary portion between the large-diameter portion and the press-fitting allowance portion of the inner surface is provided on the valve seat member, a space surrounded by the flange portion and a portion other than the flange portion in the valve seat member and the press-fitting allowance portion in the body constitutes an oil reservoir portion capable of storing oil contained in the fluid, an oil introduction portion communicating the oil reservoir portion with an inside of the body is provided on the flange portion, and the oil reservoir portion and the oil introduction portion constitute an operating fluid leakage prevention portion for suppressing leakage of the fluid.

6. The main body has a holding force strengthening portion that strengthens the holding force of the press-fitting portion. The holding force strengthening portion is composed of the press-fitting allowance portion that has been plastically processed. The valve device according to claim 4, wherein the thickness dimension of the press-fitting allowance portion is smaller than the thickness dimension of the small-diameter portion.

7. The valve device according to claim 4, wherein the outer diameter dimension of the small-diameter portion is equal to the outer diameter dimension of the press-fitting allowance portion.

8. On the outer periphery of the valve seat member, a corner portion having a surface facing the other end portion of the valve seat member is provided. The main body is provided with a caulking portion caulked inward. The valve device according to claim 1, wherein the caulking portion is provided with a caulking convex portion that engages with the corner portion.

9. The valve device according to claim 8, wherein the caulking convex portion is formed by punch caulking on the outer periphery of the main body and is constituted by the tip end portion of the caulking portion protruding inward of the main body.

10. The valve device according to claim 8, wherein the caulking convex portion bites into at least a part of the corner portion, and the bitten portion constitutes a working fluid leakage prevention portion that suppresses leakage of the fluid.

11. On the one side of the valve seat member, an annular recess recessed inward is provided. One end portion of the annular recess constitutes the corner portion. The valve device according to claim 8, wherein in the axial direction of the main body, the dimension from the one end portion of the valve seat member to the corner portion is 0.5 times or more the dimension from the corner portion to the other end portion of the caulking convex portion.

12. A check valve constituted by the valve device according to any one of claims 1 to 11.

13. A refrigeration cycle system including the check valve according to claim 12.

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