Valve device and refrigeration cycle system

Abstract

The objective of the present invention is to provide a valve device and a refrigeration cycle system with improved sealing performance.　A check valve 1 comprises a tubular main body 10 through which a fluid flows, a valve seat member 20 press-fitted into the main body 10, and a valving element 50 that opens and closes a valve port 31 provided in the valve seat member 20. The outer surface of the valve seat member 20 is provided with a press-fitting portion 33. The inner surface of the main body is provided with a press-fitted portion 13 against which the press-fitting portion 33 is slid to one side L1 from another side L2. A protruding surface portion 15 that protrudes inward into the main body 10 is provided in the press-fitted portion 13 farther on the one side L1 than an end portion on the other side L2, and the portion of close contact between the protruding surface portion 15 and the press-fitting portion 33 of the valve seat member 20 constitutes a sealing portion S that stops leakage of the fluid.

Description

Valve device and refrigeration cycle system

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

[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 element housing, a cylindrical valve seat member housed in the valve element housing, and a valve element (valve body) that opens and closes a valve port formed in the valve seat member. In this valve device, the valve element moves back and forth axially within the valve element housing to open and close the valve port, thereby controlling the flow of the fluid. The valve seat member is axially press-fitted into the valve element housing, and this press-fitting creates a seal between the outer wall of the valve seat member and the inner wall of the valve element housing.

[0003] JP 2012-145215 A

[0004] The valve device as described above may be used as a valve device constituting a part of a refrigeration cycle system, for example. In this case, the fluid to be controlled by the valve device may include, for example, CO ２ In some cases, ultra-high pressure fluids such as refrigerants and refrigerants are used. In such cases, the ultra-high pressure creates a large force that acts in a direction that expands the inner diameter of the inner wall of the valve body accommodating portion. Therefore, in a structure in which a valve seat member is simply press-fitted into the valve body accommodating portion, as in conventional valve devices, the seal between the outer wall of the valve seat member and the inner wall of the valve body accommodating portion is insufficient, and back leakage, in which the fluid leaks into unintended areas, can occur. Furthermore, this back leakage can reduce the energy efficiency of the refrigeration cycle system and the energy-saving performance of the valve device.

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

[0006] In order to solve the above problems and achieve the object, the valve device of the present invention is a valve device comprising: a cylindrical main body extending from one side to the other side to allow a fluid to flow; a valve seat member press-fitted into the main body; and a valve body opening and closing a valve port provided in the valve seat member, wherein the valve device comprises a press-fit portion provided on the outer surface of the valve seat member; and a press-fit portion provided on the inner surface of the main body, with the press-fit portion in sliding contact with the one side from the other side, and a protruding surface portion protruding toward the inside of the main body is provided on the one side of the end of the other side, and a seal portion that prevents leakage of the fluid is formed by the tight contact between the press-fit portion and the protruding surface portion.

[0007] According to the present invention, a protruding surface is provided on the press-fitted portion of the inner surface of the main body, and a seal is formed by the tight contact between the press-fitted portion of the valve seat member and the protruding surface, so that the seal can reliably prevent back leakage, in which the fluid flowing inside the main body leaks to unintended areas. This improves the sealing performance of the valve device. Therefore, if the fluid to be controlled by the valve device is, for example, CO ２ Even when an ultra-high pressure fluid such as a suction cup is used, high sealing performance can be maintained compared to a conventional valve device structure in which a valve seat member is simply press-fitted into a valve body accommodating portion, and therefore a valve device with improved sealing performance can be provided.

[0008] In this case, it is preferable that the protruding surface portion is formed as a pre-formed surface portion formed before the valve seat member is press-fitted. With this configuration, by forming the protruding surface portion using a pre-formed surface portion formed before the valve seat member is press-fitted, the press-fit portion of the valve seat member is brought into close contact with the pre-formed surface portion formed in advance on the main body to form a seal portion, so that compared to conventional valve devices that do not have a pre-formed surface portion that comes into close contact with the press-fit portion of the valve seat member, backside leakage of the fluid can be prevented even when an ultra-high pressure fluid is used as the control target of the valve device. In addition, the sealing performance of the valve device can be maintained at a high level.

[0009] The protruding surface portion is formed at a predetermined angle relative to the axis of the main body extending from the one side to the other side. This configuration allows the protruding surface portion to be molded into various shapes, such as a tapered shape inclined relative to the axis of the main body or a right-angled shape perpendicular to the axis of the main body. Furthermore, because the angle of the protruding surface portion relative to the axis can be set to a predetermined angle, the tight contact state between the press-fit portion and the protruding surface portion can be appropriately adjusted by changing this angle to suit conditions such as the materials of the main body and the valve seat member. This allows the valve device to maintain high sealing performance.

[0010] Preferably, the main body and the valve seat member are cylindrical, the press-fit portion comprises a press-fit margin portion on the other side, a small-diameter portion on the one side, and the protruding surface portion between the press-fit margin portion and the small-diameter portion, the press-fit margin portion having an inner diameter dimension before press-fitting the valve seat member smaller than the outer diameter dimension of the press-fit portion of the valve seat member before press-fitting, the small-diameter portion having an inner diameter dimension equal to or smaller than the inner diameter dimension of the press-fit margin portion, the other end of the protruding surface portion continuing to the press-fit margin portion, and the one end of the protruding surface portion continuing to the small-diameter portion. With this configuration, the valve seat member can be reliably press-fitted into the main body, and a seal can be reliably formed between the protruding surface portion and the press-fit portion.

[0011] Furthermore, the thickness of the small diameter portion is preferably greater than the thickness of the press-fit margin portion. In a valve device, for example, the small diameter portion may be crimped radially inward to fix a valve seat member press-fitted into the main body to the main body. In this case, the formation of the crimped portion may result in a portion of the small diameter portion having a reduced thickness. In this case, stress is likely to concentrate at the crimped portion when subjected to pressure from an ultra-high pressure fluid, which may locally reduce the pressure resistance of the main body. However, according to this configuration, when the crimped portion is formed, the thickness of the small diameter portion is partially reduced at the crimped portion. However, since the thickness of the small diameter portion is originally greater than the thickness of the press-fit margin portion, the pressure resistance of the main body is not locally reduced. This makes it easier to prevent cracks in the main body, which reduces the risk of external fluid leakage and improves the reliability of the valve device against ultra-high pressure fluids.

[0012] Furthermore, it is preferable that the outer diameter of the small diameter portion is equal to the outer diameter of the press-fit margin portion. With this configuration, since the outer diameter of the small diameter portion is equal to the outer diameter of the press-fit margin portion, no steps or the like due to differences in outer diameter dimensions are formed in the main body. As a result, the main body is less likely to have areas where stress concentrates, such as the boundaries of steps. This makes it easier to prevent stress corrosion cracking due to stress concentration, and improves the reliability of the valve device for ultra-high pressure fluids.

[0013] Furthermore, a check valve according to the present invention is characterized in that it is configured by any one of the valve devices described above. According to the present invention, a check valve can be configured using a valve device that improves sealing performance.

[0014] The present invention also provides a refrigeration cycle system including the check valve described above. According to the present invention, the refrigeration cycle system can be configured using a check valve that improves sealing performance, thereby improving the energy efficiency of the refrigeration cycle system.

[0015] Preferably, the other side of the press-fit portion has a large-diameter portion having a larger inner diameter than the press-fit portion, and the valve seat member has a flange portion that protrudes toward the inner surface of the main body and abuts against the inner surface at a boundary between the large-diameter portion and the press-fit portion. The space surrounded by the flange portion, the portion of the valve seat member other than the flange portion, and the press-fit portion of the main body constitutes an oil reservoir capable of storing oil contained in the fluid. The flange portion has an oil inlet port that connects the oil reservoir to the interior of the main body. The oil inlet port and the oil inlet port constitute a working fluid leakage prevention unit that prevents leakage of the fluid. With this configuration, the oil stored in the oil reservoir can be supplied between the outer surface of the valve seat member and the inner surface of the main body by capillary action. This allows the oil to more reliably prevent back leakage of the fluid, for example, even if there is a small gap or flaw between the press-fit portion on the outer surface of the valve seat member and the press-fit portion on the inner surface of the main body. Furthermore, the flange abutting against the main body makes it difficult for the oil stored in the oil reservoir to move to the other side. Therefore, compared to a configuration in which an oil reservoir is simply formed by providing a gap between the valve seat member and the main body, the following can be suppressed: That is, the so-called ejector effect, in which oil is sucked out of the oil reservoir due to being entrained in the fluid flow around the oil reservoir, can be prevented.

[0016] Furthermore, the main body preferably has a retention-strengthening portion that strengthens the retention of the press-fit portion, the retention-strengthening portion being formed by the press-fit interference portion that has been subjected to plastic processing, and the thickness of the press-fit interference portion being smaller than the thickness of the small diameter portion. With this configuration, for example, by subjecting the press-fit interference portion to plastic processing such as spinning, the hardness of the press-fit interference portion can be made higher than the hardness of the small diameter portion, making the press-fit interference portion less likely to deform. Therefore, even if the structure inside the main body is repeatedly subjected to changes such as expansion and contraction due to changes in pressure and temperature, the retention strength of the valve seat member relative to the press-fit 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] Preferably, the valve seat member has a corner on its outer periphery, the corner facing the other end of the valve seat member, the main body has a crimped portion crimped inward, and the crimped portion has a crimping protrusion that engages with the corner. With this configuration, by engaging the crimping protrusion of the crimped portion provided on the main body with the corner of the valve seat member, loosening of the crimped portion is suppressed, and the holding force of the valve seat member on the main body can be further improved, thereby further improving the pull-out strength of the valve seat member.

[0018] Furthermore, it is preferable that the crimping protrusion is formed by punch crimping the outer periphery of the main body and is configured as a tip of the crimping portion protruding inward from the main body. This configuration reduces stress generated in the crimping portion compared to a so-called roll crimping structure in which crimping is performed along the entire periphery of the main body. This makes it possible to suppress cracking of the main body and external leakage of fluid due to cracking.

[0019] Furthermore, it is preferable that the crimping protrusion bends into at least a portion of the corner, and that this bend constitutes a working fluid leakage prevention portion that suppresses leakage of the fluid. According to this configuration, by having the crimping protrusion of the main body bend into at least a portion of the corner of the valve seat member, loosening of the crimping at the crimping portion is further suppressed, making it difficult for the press-fitted valve seat member to loosen from the main body. This further improves the holding force of the valve seat member by the main body, thereby further improving the pull-out strength of the valve seat member. In addition, at this time, the valve seat member and the main body are brought closer together in the bend direction. This brings the press-fit portion that constitutes the seal portion into closer contact with the protruding surface portion, thereby increasing the surface pressure of the seal portion. This further improves the sealing performance of the seal portion. Therefore, the bend constitutes a working fluid leakage prevention portion that suppresses leakage of the fluid, thereby suppressing backside leakage of the fluid.

[0020] Preferably, the one side of the valve seat member has an inwardly recessed annular recess, the one end of the annular recess forming the corner, and the dimension from the one end of the valve seat member to the corner in the axial direction of the main body is at least 0.5 times the dimension from the corner to the other end of the crimping protrusion. This configuration ensures the axial dimension from the corner to the one end of the valve seat member, thereby ensuring the strength of the one side of the valve seat member. This prevents deformation of the one side of the valve seat member, further improving the pull-out strength of the valve seat member when the crimping protrusion is engaged with the corner.

[0021] According to the present invention, it is possible to provide a valve device and a refrigeration cycle system that improve sealing performance.

[0022] 1A and 1B are cross-sectional views of a check valve according to an embodiment of the present invention, taken along the axial direction. (A) is a cross-sectional view of the main body before a valve seat member is press-fitted, taken along the axial direction, and (B) is an enlarged cross-sectional view of the valve seat member before press-fitting, taken along the axial direction. (A) is an enlarged view of a main portion of a press-fitted portion in the main body of the check valve before the valve seat member is press-fitted, and (B) is an enlarged view of region A in FIG. 1 after the valve seat member is press-fitted, showing the dimensional relationship of each portion around the press-fitted portion. (A) is a cross-sectional view of the main body of the check valve in which a press-fitted portion is formed, taken along the axial direction. (B) is a cross-sectional view of the main body in which an inlet pipe is formed, taken along the axial direction. (C) is a cross-sectional view of the main body into which a valve seat member is press-fitted, taken along the axial direction. (A) to (C) are schematic diagrams showing variations of the pre-formed surface portion of the main body and the press-fitted portion of the valve seat member. 7(D) to 7(F) are schematic diagrams showing variations of the preformed surface portion of the main body and the press-fit portion of the valve seat member other than the variations shown in FIGS. 5(A) to 5(C). (A) is a cross-sectional view of the main body and the valve seat member taken along the axial direction immediately before the valve seat member is press-fitted, and (B) is a cross-sectional view of the main body and the valve seat member taken along the axial direction when the press-fitting of the valve seat member shown in FIG. 7(A) is completed. (A) is a schematic diagram showing the dimensional relationship of each part of the press-fitted portion before the valve seat member is press-fitted as shown in FIG. 7(A), and (B) is a schematic diagram showing the dimensional relationship of each part of the press-fitted portion after the valve seat member is press-fitted into the press-fitted portion as shown in FIG. 7(B). (A) and (B) are schematic diagrams showing variations of the dimensional relationship of each part of the press-fitted portion before the valve seat member is press-fitted. A schematic diagram of a refrigeration cycle system including a check valve. A cross-sectional view of a check valve according to a second embodiment taken along the axial direction. 15A is a cross-sectional view of a valve seat member according to a second embodiment, taken along the axial direction; FIG. 15B is an enlarged view of a main portion of the check valve shown in FIG. 11; FIG. 15C is a cross-sectional view of a check valve according to a third embodiment, taken along the axial direction; (A) is a cross-sectional view of a valve seat member according to a third embodiment, taken along the axial direction, and (B) is an enlarged cross-sectional view of region I in FIG. 14; (A) to (D) are side views of the main body, showing variations of the crimped portion; (A) is an enlarged view of region II in FIG. 14; (B) is a cross-sectional view taken along the arrows A-A in FIG. 15A; and (C) is a cross-sectional view showing another embodiment of the oil introduction portion. FIG. 15B is a cross-sectional view of a check valve according to a fourth embodiment, taken along the axial direction; and FIG. 15C is an enlarged view of region III in FIG.

[0023] A check valve 1 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 10. The check valve 1 according to this embodiment is a valve device that controls (passes or blocks) the flow of a fluid and is installed and used, for example, in the middle of a fluid flow path in a refrigeration cycle system 100 (described later). In the following description, the direction along the axis L of the main body 10 (described later) will be referred to as the "axis L direction," one side of the axis L direction will be referred to as the "one side L1," and the other side of the axis L direction will be referred to as the "other side L2." The direction from the one side L1 to the other side L2 will be referred to as the forward flow direction of the fluid, and the direction opposite to the forward flow direction will be referred to as the reverse flow direction. This is for convenience of explanation only, and does not necessarily coincide with the directions in the actual use state of the check valve 1, and does not limit the directions 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. A fluid can flow through the main body 10 in either a forward or reverse direction, but a valve element 50 (described later) prevents reverse flow. The main body 10 is cylindrically formed using a metal material such as copper and includes a valve body 11 extending in the axial direction L. A large-diameter portion 12 is formed on the inner circumferential surface (inner surface) of the valve body 11 on the other side L2. The large-diameter portion 12 is the portion of the valve body 11 with the largest inner diameter and is cylindrical. A press-fit portion 13, which has an inner diameter smaller than that of the large-diameter portion 12, is formed continuously on the one side L1 of the large-diameter portion 12 and extends toward the one side L1. A press-fit portion 33 of a valve seat member 20, which is press-fitted into the valve body 11, is in sliding contact (press-fit) with the press-fit portion 13 from the other side L2 toward the one side L1.

[0025] As shown in Figures 2(A) and 3(A), the press-fit portion 13 includes, from the other side L2 toward the one side L1, a press-fit allowance portion 14, a protruding surface portion 15, and a small-diameter portion 16. The "press-fit allowance" in the "press-fit allowance portion 14" typically refers to the radial difference between the outer diameter β1 of the press-fit portion 33 of the valve seat member 20 and the inner diameter of the press-fit portion 13 of the valve body 11, and the "press-fit allowance portion 14" refers to the range in the valve body 11 along the axis L where this "press-fit allowance" exists. The press-fit allowance portion 14 is cylindrical and continuous with the large-diameter portion 12. In the press-fit allowance portion 14 shown in Figure 2(A), the inner diameter α1 of the valve seat member 20 before press-fitting is smaller than the inner diameter of the large-diameter portion 12 and smaller than the outer diameter β1 of the press-fit portion 33 of the valve seat member 20 before press-fitting, as shown in Figure 2(B). The difference between the inner diameter dimension α1 and the outer diameter dimension β1 (press-fit allowance) ensures that the valve seat member 20 is press-fitted into the valve body 11. As shown in Fig. 3(A) , the protruding surface portion 15 is an inner wall surface that protrudes radially inward (into the body 10), with an end portion on the other side L2 continuing to the press-fit allowance portion 14 and an end portion on the one side L1 continuing to the small diameter portion 16. That is, the protruding surface portion 15 is provided on the one side L1 of the end portion on the other side L2 of the press-fit portion 13, between the press-fit allowance portion 14 and the small diameter portion 16, and protrudes toward the inside of the body 10.

[0026] The protruding surface portion 15 is formed at a predetermined angle θ1 with respect to the axis L. The predetermined angle θ1 is the angle formed by the intersection of the wall surface of the upper protruding surface portion 15 and the wall surface of the lower protruding surface portion 15 when extended toward one side L1 in the cross-sectional view shown in FIG. 2A, and can be set appropriately. As shown in FIG. 3A, the protruding surface portion 15 has a pre-formed surface portion 15a that is formed in advance before the valve seat member 20 is press-fitted. That is, the protruding surface portion 15 is composed of the pre-formed surface portion 15a. The formation of the protruding surface portion 15 will be described in detail later.

[0027] The small-diameter portion 16 is an inner wall surface constituting the one side L1 portion of the press-fit portion 13, and is formed in a cylindrical shape continuing from the protruding surface portion 15 and extending toward the one side L1. As shown in FIG. 3A , the inner diameter dimension α2 of the small-diameter portion 16 is set to be equal to or smaller than the inner diameter dimension α1 of the press-fit margin portion 14. As shown in FIG. 1 , the one side L1 portion of the press-fit portion 13 in the valve body 11 is formed with a crimped portion 17 that engages with the press-fitted valve seat member 20. The crimped portion 17 is formed by crimping the one side L1 portion of the valve body 11 from the outside to the inside in the radial direction, and engages with at least the end of the one side L1 of an annular recess 34 (described later) of the valve seat member 20. An inlet pipe 18 is continuous with the end of the one side L1 of the valve body 11 formed in this manner.

[0028] The inlet pipe 18 is cylindrical and extends to one side L1. The inlet pipe 18 includes a large-diameter inlet pipe 18a connected to the one side L1 of the valve body 11 and a small-diameter inlet pipe 18b connected to the one side L1 of the large-diameter inlet pipe 18a. The outer diameter of the small-diameter inlet pipe 18b is smaller than the outer diameter of the large-diameter inlet pipe 18a. Meanwhile, an outlet pipe 19 is connected to the end of the other side L2 of the valve body 11. The outlet pipe 19 includes a small-diameter outlet pipe 19a connected to the valve body 11 and a large-diameter outlet pipe 19b connected to the other side L2 of the small-diameter outlet pipe 19a. The outer and inner diameters of the large-diameter outlet pipe 19b are larger than the large and inner diameters of the small-diameter outlet pipe 19a. A valve seat member 20 is press-fitted into the valve body 11 of the main body 10 from the other side L2 toward the one side L1.

[0029] The valve seat member 20 is formed into a cylindrical shape using a metal material such as brass. As shown in FIG. 2B , the valve seat member 20 includes a cylindrical valve seat portion 30 extending in the axial direction L. A valve port 31 is formed at the center of the valve seat portion 30, penetrating in the axial direction L. The open end of the valve port 31 on the other side L2 is expanded radially outward to form a step, and this step forms a valve seat 32. A press-fit portion 33 that slides (is press-fitted) into the press-fit portion 13 of the main body 10 is formed on the outer peripheral surface (outer surface) of the valve seat portion 30. The press-fit portion 33 includes a flat portion 33a extending in the axial direction L and an inclined surface portion 33b that is continuous with the flat portion 33a and inclined with respect to the axial direction L. The flat portion 33a extends substantially parallel to the axial direction L. The inclined surface portion 33b (press-fit portion 33) is formed at a predetermined angle θ2 with respect to the axial direction L.

[0030] The predetermined angle θ2 is the angle formed by the intersection of the upper inclined surface portion 33b and the lower inclined surface portion 33b when extended toward one side L1 in the cross-sectional view shown in FIG. 2B , and can be set appropriately. The inclined surface portion 33b is in close contact with the protruding surface portion 15 when the valve seat member 20 is press-fitted into the valve body 11. As shown in FIG. 1 , the seal portion S is formed by the close contact between the inclined surface portion 33b and the protruding surface portion 15. The seal portion S prevents back leakage, which is leakage of fluid to unintended locations. Specifically, when fluid flows in the reverse direction, leakage is prevented from occurring between the press-fit portion 33 of the valve seat member 20 and the press-fit portion 13 of the valve body 11, except for the seating portion where the valve disc 50 and the valve seat 32 contact. An annular recess 34 recessed radially inward is formed on one side L1 of the press-fit portion 33. The annular recess 34 is engaged with the crimped portion 17 of the valve body 11. This restricts displacement of the valve seat member 20 press-fitted into the valve body 11 in the direction of the axis L, preventing the valve seat member 20 from slipping out of the valve body 11. Meanwhile, a flange portion 35 that protrudes radially outward is formed on the other side L2 of the press-fit portion 33. The flange portion 35 is formed around the entire circumference of the axis L.

[0031] The flange portion 35 is provided so as to be able to abut against the boundary between the large diameter portion 12 and the press-fit portion 13 of the main body 10 toward the one side L1. When the flange portion 35 abuts against the boundary between the large diameter portion 12 and the press-fit portion 13, displacement of the valve seat member 20 toward the one side L1 is restricted. A valve holder portion 40 is formed on the other side L2 of the valve seat portion 30. The valve holder portion 40 is formed in a cylindrical shape that rises from the end of the other side L2 of the valve seat portion 30 toward the other side L2. The interior of the valve holder portion 40 forms a valve chamber 41, and a valve element 50 is housed within 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 that penetrate radially are formed in the peripheral wall surface of the valve holder portion 40. This allows communication between the valve chamber 41 and the interior of the valve main body 11. A valve stopper 43 is attached to the inner surface of the end of the other side L2 of the valve holder part 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 movement of the valve element 50, which it abuts, toward the other side L2.

[0032] The valve element 50 housed in the valve holder 40 is cylindrical and made of resin. The valve element 50 is slidable along the axis L within the valve chamber 41 and opens and closes the valve port 31 by moving back and forth along the axis L. As shown in FIG. 2B , the valve element 50 includes a substantially cylindrical valve element main body 51. Four grooves 52 extending along the axis L are formed on the outer surface of the valve element main body 51, resulting in a substantially cross-shaped cross section of the valve element main body 51 intersecting the axis L. The grooves 52 allow only the outer periphery of the substantially cross-shaped cross section to slide against the inner periphery of the valve holder 40, reducing the resistance to movement of the valve element 50 relative to the valve holder 40 around the axis L and allowing for smooth sliding movement of the valve element 50. A lightening portion 53 is formed in the center of the valve element main body 51, which is lightened from the center of the end face on the other side L2 toward the one side L1 so as not to penetrate the valve element 50. The recessed portion 53 suppresses the occurrence of sink marks, air bubbles, etc. during resin molding of the valve body 50, and also contributes to reducing the weight of the valve body 50. The end face of one side L1 of the valve body main body 51 forms a sealing surface 54 that abuts against the valve seat 32 to close the valve port 31.

[0033] Next, we will explain how to manufacture the check valve 1. First, a cylinder 10a extending in the direction of the axis L is formed using a metal material such as copper. Next, as shown in Figure 4(A), a press-fit margin portion 14, a protruding surface portion 15, and a small diameter portion 16 are formed on the cylinder 10a as the press-fit portion 13.

[0034] In this press-fit portion 13, 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-fit portion 13, as shown in FIG. 3A. Also, as shown in FIG. 3A, before the valve seat member 20 is press-fitted, the thickness dimension T1 (wall thickness) of the small diameter portion 16 is greater than the thickness dimension T2 (wall thickness) of the press-fit margin portion 14. The outer diameter dimension D1 of the small diameter portion 16 is equal to the outer diameter dimension D2 of the press-fit margin portion 14. In this embodiment, the protruding surface portion 15 of the press-fit portion 13 formed at this stage is specifically referred to as a preformed surface portion 15a. The preformed surface portion 15a can be formed with various shapes and inclination angles. FIGS. 5A to 5C are schematic diagrams showing variations of the preformed surface portion 15a (protruding surface portion 15) of the main body 10 and the press-fit portion 33 of the valve seat member 20. 6(D) to 6(F) are schematic diagrams showing variations other than those shown in FIGS. 5(A) to 5(C) in the formed surface portion 15a of the main body 10 and the press-fit portion 33 of the valve seat member 20. As shown in FIG. 5(A), the formed surface portion 15a can be formed so that its predetermined angle θ1 is equal to the predetermined angle θ2 of the inclined surface portion 33b (press-fit portion 33).

[0035] As shown in FIG. 5B, the preformed surface portion 15a can be formed so that its predetermined angle θ1 is greater than the predetermined angle θ2 of the inclined surface portion 33b. As shown in FIG. 5C, the preformed surface portion 15a can be formed so that its predetermined angle θ1 is smaller than the predetermined angle θ2 of the inclined surface portion 33b. As shown in FIG. 6D, the preformed surface portion 15a can be formed so that its predetermined angle θ1 is 90°. As shown in FIG. 6E, the preformed surface portion 15a can also be formed with curved R-portions 14c at the end (edge ​​portion) of the other side L2 and the end (edge ​​portion) of the one side L1. As shown in FIG. 6F, the preformed surface portion 15a can also be formed so that it protrudes radially inward so that the predetermined angle θ1 is 90°.

[0036] Next, as shown in FIG. 4B, the one side L1 of the cylinder 10a is machined to form the inlet pipe 18, which includes the large-diameter inlet pipe 18a and the small-diameter inlet pipe 18b. Then, as shown in FIG. 4C, the 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. 7A, when the inclined surface portion 33b of the valve seat portion 30 is located on the other side L2 relative to the press-fit margin portion 14, the valve seat portion 30 is pressed (press-fitted) into the cylinder 10a from the other side L2 to the one side L1. As shown in FIG. 7B, the valve seat portion 30 moves to the one side L1 and is press-fitted. Then, as shown in FIG. 7B, the inclined surface portion 33b of the press-fit portion 33 comes into close contact with the formed surface portion 15a (protruding surface portion 15), and the close contact portion forms the seal portion S. In this manner, the press-fit portion 33 of the valve seat member 20 is press-fitted into the press-fit margin portion 14, and the inclined surface portion 33b forms a seal portion S.

[0037] In addition, when the protruding surface portion 15 (pre-formed surface portion 15a) is formed in advance as in this embodiment, the dimensional relationship between each part of the press-fitted portion 13 before and after the valve seat member 20 is press-fitted is as shown in Figures 8(A) and 8(B). Figure 8(A) is a schematic diagram showing the dimensional relationship between each part of the inner circumferential surface of the main body 10 before the valve seat member 20 is press-fitted as shown in Figure 7(A), and Figure 8(B) is a schematic diagram showing the dimensional relationship between each part of the press-fitted portion 13 after the valve seat member 20 is press-fitted into the press-fitted portion 13 as shown in Figure 7(B). As shown in Figure 8(A), before the valve seat member 20 is press-fitted, the relationship between the inner diameter dimension α1 of the press-fit margin portion 14, the inner diameter dimension α2 of the 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 inner diameter dimension α1 > inner diameter dimension α2 = inner diameter dimension α4. On the other hand, as shown in FIG. 8B , after the valve seat member 20 is press-fitted, the relationship among the inner diameter dimension α6 of the press-fit portion 14, the inner diameter dimension α2 of the one side portion 16 a of the small diameter portion 16, and the inner diameter dimension α4 of the other side portion 16 b of the small diameter portion 16 is inner diameter dimension α6 > inner diameter dimension α2 = inner diameter dimension α4.

[0038] That is, the relationship in size among the inner diameters of the press-fit margin portion 14, the 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 valve seat member 20 is press-fitted. This also applies when the relationship among the inner diameters of the press-fit margin portion 14, the 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. 9A. FIGS. 9A and 9B are schematic diagrams showing variations in the dimensional relationship among the parts of the press-fitted portion 13 before the press-fitting of the valve seat member 20. As shown in FIG. 9A, before the press-fitting of the valve seat member 20, the relationship among the inner diameter dimension α1 of the press-fit margin portion 14, the inner diameter dimension α2 of the 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 inner diameter dimension α2 < inner diameter dimension α1 = inner diameter dimension α4.

[0039] 9(B), before the valve seat member 20 is press-fitted, the relationship between the inner diameter dimension α1 of the press-fit margin portion 14, the inner diameter dimension α2 of the 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 inner diameter dimension α4 < inner diameter dimension α2 < inner diameter dimension α1. Thus, even in a configuration in which the dimensional relationships of the various parts are different from those of the embodiment shown in FIGS. 8(A) and 8(B), the relationship between the inner diameter dimensions of the press-fit margin portion 14, the 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 valve seat member 20 is press-fitted, although this is not shown in the figure.

[0040] The valve seat member 20, which has been press-fitted into the valve body 11, is restricted from moving toward the one side L1 by the flange portion 35 abutting against the boundary between the large-diameter portion 12 and the press-fit portion 13 of the valve body 11, and this abutment completes the press-fitting of the valve seat member 20. After the press-fitting of the valve seat member 20 is complete, as shown in FIG. 4(C), a crimped portion 17 is formed in the valve body 11, and the crimped portion 17 is engaged with the annular recess 34 to fix the valve seat member 20 to the valve body 11. Then, the other side L2 of the cylinder 10a is machined to form the outlet pipe 19, which includes a small-diameter outlet pipe 19a and a large-diameter outlet pipe 19b, as shown in FIG. 1. This completes the manufacture of the check valve 1.

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

[0042] Here, the following effects can be achieved by setting the height Y of the protruding surface portion 15 to a small value, such as approximately 1 / 10 to 1 / 1 of the thickness T2 of the press-fit margin portion 14 after the valve seat member 20 is press-fitted, or to a value 1 / 10 to 1 / 3 or 1 / 10 to 1 / 4 of the thickness T2. For example, if the height Y of the protruding surface portion 15 is set to a value greater than twice (200%) the thickness T2 of the press-fit margin portion 14 after the valve seat member 20 is press-fitted, the protruding surface portion 15 functions as a positioning stopper for the valve seat member 20 during press-fitting, but is not suitable for sealing against back leakage of fluid. This is because the inclined surface area of ​​the protruding surface portion 15 is large, increasing the contact area between the protruding surface portion 15 and the press-fit portion 33, thereby dispersing the contact load generated between the protruding surface portion 15 and the press-fit portion 33. However, in the present invention, the height dimension Y of the protruding surface portion 15 is small, about 1 / 10 to 1 / 1 times (10 to 100%) the thickness dimension T2 of the press-fit margin portion 14 after the valve seat member 20 is press-fitted. The small protruding surface portion 15 reduces the contact area between the press-fit portion 33 of the valve seat member 20 and the protruding surface portion 15, preventing the above-described contact load from being dispersed. This enhances the pressure-sealing effect between the protruding surface portion 15 and the press-fit portion 33, thereby improving sealing performance. Furthermore, by setting the height dimension Y to about 1 / 10 to 1 / 3 times (10 to 33%) the thickness dimension T2, the contact area between the protruding surface portion 15 and the press-fit portion 33 is further reduced, further enhancing the pressure-sealing effect and improving sealing performance. In particular, if the height dimension Y is set to approximately 1 / 10 to 1 / 4 times (10 to 25%) the thickness dimension T2, the contact area between the protruding surface portion 15 and the press-fit portion 33 becomes even smaller, thereby further increasing the crimping seal effect and improving sealing performance.

[0043] Furthermore, the height dimension Y of the protruding surface portion 15 is preferably set to about 4% to 10% of the length dimension α5 of the press-fit margin portion 14, and more preferably to about 5%. Furthermore, the length dimension X of the protruding surface portion 15 is preferably set to about 20% to 50% of the length dimension α5 of the press-fit margin portion 14. By configuring in this manner, it is possible to provide the protruding surface portion 15 with a length dimension X and a height dimension Y that are sufficient relative to the length dimension α5 of the press-fit margin portion 14. Therefore, when the seal portion S is formed on the protruding surface portion 15, a sufficient seal area can be ensured while the above-mentioned close contact area is small, and sealing performance can be significantly improved.

[0044] The check valve 1 configured as described above can be used in various positions. For example, when the axis L shown in FIG. 1 is vertical, i.e., when the check valve 1 is used in a vertically installed state, it operates as follows. First, when the valve element 50 is seated on the valve seat 32 due to its own weight and in the position shown in FIG. 1 (hereinafter also referred to as the valve closed position), fluid flows in the forward direction from the inlet pipe 18 to the outlet pipe 19. Then, the valve element 50 is pushed by the fluid flowing out of the valve port 31 and lifts off the valve seat 32, opening the valve port 31, establishing the valve open state, and moving to a position where it abuts the valve stopper 43. Then, when the flow of fluid in the forward direction stops, the valve element 50 falls under its own weight and seats back on the valve seat 32, closing the valve port 31 and establishing the valve closed state. Furthermore, when the check valve 1 is used in a horizontally installed state or in a vertically installed state upside down, it operates as follows. First, when the valve element 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 pressure difference at this time causes the fluid to flow in the reverse direction.

[0045] As a result, the valve element 50 is pressed against the valve seat 32 and maintained in a seated state. In this state, if the pressure in the inlet pipe 18 increases and fluid flows in the forward direction from the inlet pipe 18 to the outlet pipe 19, the valve element 50 is pushed by the fluid flowing out of the valve port 31 and lifts off the valve seat 32. Then, when the forward flow of fluid stops and the pressure on the outlet pipe 19 side again becomes higher than that on the inlet pipe 18 side, the resulting pressure difference causes fluid to flow in the reverse direction. This causes the valve element 50 to reseat on the valve seat 32. When fluid flows in this manner, the provision of the seal portion S in this embodiment prevents back leakage, in which fluid leaks to unintended locations between the main body 10 and the valve seat member 20. Specifically, for example, as described above, when fluid flows in the reverse direction, fluid is prevented from leaking between the press-fit portion 33 of the valve seat member 20 and the press-fit portion 13 of the main body 10, at locations other than the seating portion where the valve element 50 and the valve seat 32 abut. Furthermore, when the valve body 50 is seated on the valve seat 32, the valve body 50 is pressed against the valve seat 32, and a pressure load is applied to the valve seat member 20 in the valve closing direction, so that the inclined surface portion 33b that constitutes the seal portion S is pressed against the protruding surface portion 15, resulting in closer contact between the inclined surface portion 33b and the protruding surface portion 15 and further improving the sealing performance.

[0046] The dimensional relationship of the valve body 11 after the valve seat member 20 is press-fitted will now be described with reference to Figure 3(B). As shown in Figure 3(B), the thickness T1 of the small diameter portion 16 is larger than the thickness T2 of the press-fit margin portion 14 (i.e., thickness T1 > thickness T2). The outer diameter D1 of the small diameter portion 16 is equal to the outer diameter D2 of the press-fit margin portion 14 (i.e., outer diameter D1 = outer diameter D2). The outer diameter D2 may be slightly larger than the outer diameter D1, thereby forming a slight taper that smoothly connects the outer peripheral surface of the small diameter portion 16 to the outer peripheral surface of the press-fit margin portion 14 without any steps.

[0047] In the check valve described in Patent Document 1, as shown in FIG. 2(b) of Patent Document 1, the thickness of the portion corresponding to the small diameter portion 16 of this embodiment is the same as the thickness of the portion corresponding to the press-fit margin portion 14, and when the valve seat member is press-fitted, the entire valve body accommodating portion is expanded in diameter without changing its wall thickness. Therefore, the dimension corresponding to the outer diameter D2 of this embodiment (the outer diameter of the portion corresponding to the press-fit margin portion 14 of this embodiment) is larger than the dimension corresponding to the outer diameter D1 of this embodiment (the outer diameter of the portion corresponding to the small diameter portion 16 of this embodiment), which is different from this embodiment. Furthermore, the check valve described in Patent Document 1 differs from this embodiment in that a step is formed on the outer peripheral surface of the valve body accommodating portion before the valve seat member is press-fitted.

[0048] The reason why the thickness and outer diameter relationships between the portion corresponding to the small diameter portion 16 and the portion corresponding to the press-fit margin portion 14 differ from those of the present embodiment is thought to be that the check valve described in Patent Document 1 controls general fluids in refrigeration cycle systems, and does not control ultra-high pressure fluid pressure, as in the present embodiment. In other words, the check valve described in Patent Document 1 requires lower pressure resistance than the present embodiment. Therefore, the check valve described in Patent Document 1 has a valve body accommodating portion with a significantly thinner wall thickness, for example, about half that of the valve body 11 of the present embodiment, which makes the valve body accommodating portion susceptible to deformation due to the press-fit of the valve seat member. Therefore, as described above, the thickness of the portion corresponding to the small diameter portion 16 and the portion corresponding to the press-fit margin portion 14 remains the same while the diameter is expanded, and the dimension corresponding to the outer diameter D2 is larger than the dimension corresponding to the outer diameter D1.

[0049] In this embodiment, the thickness T1 of the small diameter portion 16 is larger than the thickness T2 of the press-fit margin portion 14 (thickness T1 > thickness T2), which provides the following advantages. Because the thickness T1 of the small diameter portion 16 is partially reduced by the formation of the crimped portion 17, if the thickness T1 is equal to the thickness T2, the pressure resistance of the valve body 11 may be locally reduced at the crimped portion 17. However, in this embodiment, the thickness T1 of the small diameter portion 16 is originally larger than the thickness T2 of the press-fit margin portion 14, so the formation of the crimped portion 17 does not locally reduce the pressure resistance of the valve body 11. Therefore, compared to the check valve described in Patent Document 1, in which the thickness of the portion corresponding to the small diameter portion 16 and the thickness of the portion corresponding to the press-fit margin portion 14 are the same, cracks in the valve body 11 caused by reduced pressure resistance are more easily prevented. Furthermore, preventing such cracks reduces the risk of external fluid leakage and improves the reliability of the check valve 1 against ultra-high-pressure fluids.

[0050] Furthermore, in this embodiment, the outer diameter dimension D1 of the small diameter portion 16 is equal to the outer diameter dimension D2 of the press-fit portion 14, which provides the following effect. Because the outer diameter dimension D1 of the small diameter portion 16 is equal to the outer diameter dimension D2 of the press-fit portion 14, a step or the like caused by the difference between the outer diameter dimensions D1 and D2 does not occur in the valve body 11, and stress concentration areas, such as at the boundary of the step, are unlikely to occur. This makes it easier to prevent stress corrosion cracking due to stress concentration. This effect is particularly significant compared to the check valve described in Patent Document 1, in which the dimension corresponding to the outer diameter dimension D2 is larger than the dimension corresponding to the outer diameter dimension D1, resulting in a step on the outer peripheral surface of the valve body accommodating portion. In other words, in this embodiment, stress corrosion cracking of the valve body 11 is more easily prevented than the check valve described in Patent Document 1, thereby improving the reliability of the check valve 1 for ultra-high-pressure fluids.

[0051] As described above, the above effect is the same even in the case where, in this embodiment, the outer diameter dimension D2 is slightly larger than the outer diameter dimension D1 and there is a slight slope (taper) that smoothly connects the outer peripheral surface of the small diameter portion 16 to the outer peripheral surface of the press-fit margin portion 14 without any steps. With this configuration, even if there is a difference between the outer diameter dimensions D1 and D2, no parts where stress concentrates, such as the boundary between the steps, are formed, and stress corrosion cracking of the valve body 11 is prevented.

[0052] Furthermore, in this embodiment, as described above, thickness T1 is greater than thickness T2, and outer diameter D1 is equal to outer diameter D2. With this configuration, the protruding surface portion 15 is formed on the valve body 11 such that thickness T1 is greater than thickness T2. Therefore, the seal portion S can be formed at the contact portion between the protruding surface portion 15 and the press-fit portion 33, preventing back leakage of fluid. Furthermore, because outer diameter D1 is equal to outer diameter D2, stress concentration areas, such as the boundary between steps, are less likely to occur on the valve body 11. This prevents stress corrosion cracking due to stress concentration.

[0053] As shown in FIG. 10 , this check valve 1 is installed midway through a fluid flow path in a refrigeration cycle system 100. The refrigeration cycle system 100 is used, for example, in an air conditioner such as a commercial air conditioner. The refrigeration cycle system 100 includes 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 via piping. To prevent backflow of fluid to each compressor 105, the check valve 1 is connected between the discharge (high-pressure output) side of each compressor 105 and the four-way valve 104, with the compressor 105 on the inlet pipe 18 side and the four-way valve 104 on the outlet pipe 19 side. During cooling operation, as indicated by solid arrow D101, the fluid is compressed by the compressor 105 and then flows through the check valve 1 and the four-way valve 104 to the outdoor heat exchanger 102. After releasing heat in the outdoor heat exchanger 102, the fluid 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 heating operation, as indicated by the dotted arrow D102, the fluid is compressed by the compressor 105 and then passes through the check valve 1 and the four-way valve 104 to the indoor heat exchanger 101. The fluid then releases heat in the indoor heat exchanger 101, flows through the expansion valve 103 to the outdoor heat exchanger 102, absorbs heat in the outdoor heat exchanger 102, and returns to the compressor 105 through the four-way valve 104. The refrigeration cycle system 100 repeats these cycles to cool or heat the room. For example, under conditions of high cooling load, three compressors 105 are operated simultaneously, and each of the three check valves 1 is fully open. Under conditions of low cooling load, operation of only one compressor 105 is sufficient, and the other two compressors 105 are not operated. At this time, the pressure in the outlet pipes 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 become closed.

[0055] As described above, according to the embodiment described above, the protruding surface portion 15 is provided on the press-fit portion 13 on the inner surface of the main body 10, and the seal portion S is formed by the tight contact between the press-fit portion 33 of the valve seat member 20 and the protruding surface portion 15. This reliably prevents back leakage, in which the fluid flowing inside the main body 10 leaks into unintended areas, with the seal portion S. This improves the sealing performance of the check valve 1 (valve device). Therefore, even when an ultra-high-pressure fluid or the like is used as the fluid to be controlled by the check valve 1, high sealing performance can be maintained compared to a structure in which the valve seat member is simply press-fit into the valve disc accommodating portion, as in conventional valve devices. Therefore, a check valve 1 with improved sealing performance can be provided.

[0056] Furthermore, in this embodiment, the protruding surface portion 15 is formed by the pre-formed surface portion 15a formed before the valve seat member 20 is press-fitted, and the seal portion S is formed by bringing the press-fit portion 33 of the valve seat member 20 into close contact with the pre-formed surface portion 15a formed in advance on the main body 10, so that backside leakage of fluid can be prevented even when an ultra-high pressure fluid is used as the control target of the check valve 1, compared to conventional valve devices that do not have the pre-formed surface portion 15a that comes into close contact with the press-fit portion 33 of the valve seat member 20. Furthermore, the sealing performance of the check valve 1 can be maintained at a high level.

[0057] Furthermore, according to this embodiment, the formed surface portion 15a (protruding surface portion 15) is formed at a predetermined angle θ1 with respect to the axis L. Therefore, the protruding 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 perpendicular to the axis L of the main body 10. Furthermore, because the formed surface portion 15a can be set at the predetermined angle θ1 with respect to the axis L, the tight contact state between the press-fit portion 33 and the protruding surface portion 15 can be appropriately changed by changing this angle in accordance with 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 at a high level. The shape of the protruding surface portion 15 is not limited to the tapered shape or right-angled shape described above. For example, instead of the inclined surface of the tapered portion in the tapered shape, a convex R shape or a concave R shape connecting both ends of the tapered portion may be used.

[0058] According to this embodiment, the main body 10 and the valve seat member 20 are cylindrical, and the press-fit portion 13 is provided with a press-fit margin portion 14, a protruding surface portion 15, and a small-diameter portion 16. The press-fit margin portion 14 has an inner diameter α1 before the valve seat member 20 is press-fitted, which is smaller than the outer diameter β1 of the press-fit portion 33 of the valve seat member 20 before press-fitting. The small-diameter portion 16 has an inner diameter α2 that is equal to or smaller than the inner diameter α1 of the press-fit margin portion 14, and the end of the other side L2 of the protruding surface portion 15 is continuous with the press-fit margin portion 14, and the end of the one side L1 of the protruding surface portion 15 is continuous with the small-diameter portion 16. This configuration allows the valve seat member 20 to be reliably press-fitted into the main body 10, and reliably forms a seal portion S between the protruding surface portion 15 and the press-fit portion 33.

[0059] Furthermore, according to this embodiment, when the crimped portion 17 is formed in the valve body 11, the thickness T1 of the small diameter portion 16 is locally reduced at the crimped portion 17, but because the thickness T1 of the small diameter portion 16 is originally larger than the thickness T2 of the press-fit portion 14, there is no local decrease in the pressure resistance of the valve body 11 (main body 10). This makes it easier to prevent cracks in the valve body 11, and preventing such cracks reduces the risk of external leakage of fluid and improves the reliability of the check valve 1 for ultra-high-pressure fluids.

[0060] Furthermore, according to this embodiment, the outer diameter dimension D1 of the small diameter portion 16 is equal to the outer diameter dimension D2 of the press-fit portion 14, so that no steps or the like due to differences in outer diameter dimensions are formed in the main body 10. As a result, the valve main body 11 (main body 10) is less likely to have areas where stress concentrates, such as the boundaries of steps. This makes it easier to prevent stress corrosion cracking due to stress concentration, and improves the reliability of the check valve 1 for ultra-high-pressure fluids.

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

[0062] The above-described embodiments merely represent typical embodiments of the present invention, and the present invention is not limited to these. In other words, 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 maintained, such modifications are naturally included within the scope of the present invention. For example, in the description of this embodiment, the inlet pipe 18 is disposed on one side L1 of the valve body 11, and the outlet pipe 19 is disposed on the other side L2. However, this arrangement may be reversed, and the inlet pipe 18 may be disposed on the other side L2 of the valve body 11, and the outlet pipe 19 may be disposed on the one side L1 of the valve body 11.

[0063] Furthermore, the check valve 1 is merely one example of a valve device in the present invention, and the present invention can of course be applied to other valve devices. For example, the present invention may be applied to a slide-type switching valve or motor-operated valve that has multiple valve ports in a valve body and controls the flow of fluid through the valve ports, a solenoid valve that has a plunger and a solenoid coil, 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 that has an operating part for moving the valve element back and forth, etc. In this case, the valve device does not necessarily have to be used in the refrigeration cycle system 100, and can be used in various devices that control fluids.

[0064] In the above-described embodiment, the outer diameter dimension D1 of the small diameter portion 16 is equal to the outer diameter dimension D2 of the press-fit 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-fit portion 14 means that the outer diameter dimension D2 of the press-fit portion 14 is within the range of 0% to +3% of 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 a check valve 1A according to the second embodiment, taken along the axis L. FIG. 12 is a cross-sectional view of a valve seat member 20A according to the second embodiment, taken along the axis L. FIG. 13 is an enlarged view of a main portion 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 crimped portion 17 described above is omitted from one side L1 of the press-fit portion 13A. Also, as shown in FIG. 12, in the check valve 1A, the annular recess 34 with which the crimped portion 17 engages is omitted from one side L1 of the press-fit portion 33A of the valve seat member 20A. In the check valve 1A configured in this manner, a press-fit margin portion 14A is formed in the press-fit portion 13A, as shown in FIG. 13. The press-fit margin portion 14A corresponds to the press-fit margin portion 14 in the above-described embodiment. The press-fit margin 14A constitutes a pre-formed surface portion that is formed before the valve seat member 20A is press-fitted.

[0066] The press-fit interference portion 14A serving as a preformed surface portion in the second embodiment is formed by applying plastic processing to the inner surface of the main body 10A. This plastic processing results in a thickness T2 of the press-fit interference portion 14A that is smaller than the thickness T1 of the small diameter portion 16A. By forming the press-fit interference portion 14A with a thickness T2 smaller than the thickness T1 of the small diameter portion 16A through plastic processing, the hardness of the press-fit interference portion 14A is increased compared to the hardness of the small diameter portion 16A, making the press-fit interference portion 14A less likely to deform. Therefore, even if the internal structure of the main body 10A undergoes repeated changes such as expansion and contraction due to changes in pressure and temperature, the holding strength of the main body 10A relative to the press-fit portion 33A of the valve seat member 20A can be maintained high, thereby stabilizing the sealing performance of the seal portion S. Furthermore, this configuration allows the holding force of the valve seat member 20A relative to the press-fit portion 33A to be maintained without providing a crimping portion 17 on the main body 10A. Therefore, for example, the removal strength of the valve seat member 20A can be improved against repeated contact (collision) of the valve disc 50 with the valve stopper 43 when the valve is open. In this way, the press-fit margin portion 14A constitutes a holding force strengthening portion that strengthens the holding force of the press-fitted portion 13A.

[0067] The plastic processing can be selected as appropriate as long as it can produce work hardening. For example, although not shown, a cylinder extending in the direction of axis L is formed using a metal material that will form main body 10A, a rod-shaped jig or the like is inserted into the cylinder, and a portion of the outer wall of the cylinder is pressed radially inward from the outside by spinning or the like. In this way, the outer peripheral shape of the rod-shaped jig is transferred to the inner peripheral surface of the cylinder, thereby forming press-fit margin portion 14A.

[0068] Next, a third embodiment will be described. FIG. 14 is a cross-sectional view of a check valve 1B according to the third embodiment taken along the axis L. FIG. 15(A) is a cross-sectional view of a valve seat member 20B according to the third embodiment taken along the axis L, and FIG. 15(B) is an enlarged cross-sectional view of region I in FIG. 14. FIGS. 16(A) to 16(D) are side views of the main body 10A, main body 10B, and main body 10C showing variations of the crimped portion 17B and the crimped portion 17C. FIG. 17(A) is an enlarged view of region II in FIG. 14, FIG. 17(B) is a cross-sectional view taken along 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 according to the third embodiment includes a large-diameter portion 12B and a press-fit portion 13B on the inner circumferential surface of the main body 10B. The press-fit portion 13B includes, from the other side L2 toward the one side L1, a press-fit margin portion 14B, a protruding surface portion 15B, and a small diameter portion 16B.

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

[0070] Next, the valve seat member 20B will be described. As shown in FIG. 15A, the valve seat member 20B has an annular recess 34B recessed inward on one side L1 of the press-fit portion 33B. The end of the annular recess 34B on one side L1 forms a corner 34a having a surface 34a1 facing the end of the other side L2 of the valve seat member 20B. As shown in FIG. 15B, after the valve seat member 20B is press-fitted into the main body 10B, when the crimped portion 17B is formed, the crimped protrusion 17B1 bites into and engages with part of the corner 34a. This makes the valve seat member 20B less likely to loosen from the main body 10B than a structure in which the crimped protrusion 17B1 simply abuts against the corner 34a. This further improves the holding force of the valve seat member 20B by the main body 10B, thereby further improving the pull-out strength of the valve seat member 20B.

[0071] At this time, the valve seat member 20B and the main body 10B are brought closer together in the wedged direction. This allows the inclined surface 33b of the press-fit portion 33B constituting the seal portion S to be more closely fitted to the protruding surface 15B of the main body 10B, thereby increasing the surface pressure of the seal portion S. This further improves the sealing performance of the seal portion S. Therefore, the wedged portion constitutes a working fluid leakage prevention portion that suppresses fluid leakage, thereby preventing backside leakage. In FIG. 15(B), the symbol V indicates the amount of wedged portion 17B1 into the corner 34a. This amount of wedged portion is represented by the distance between a line C1 perpendicular to a virtual line c3 drawn from the intersection of the virtual lines c1 and c2 toward the vertex of the corner 34a, and a line C2 parallel to the line C1 and tangent to the wedged portion 17B1. It is preferable that the amount of wedged portion V be approximately 1% to 20% of the thickness T3 of the small diameter portion 16B. By doing this, the sealing performance that can appropriately prevent back leakage by the part that bites into the corner portion 34a (working fluid leakage prevention part) can be maintained, while deformation of the valve seat member 20B when it bites into the corner portion 34a can be suppressed.

[0072] The dimension in the axial direction L from the end of the one side L1 of the valve seat member 20B to the corner 34a is defined as dimension α7. The dimension from the corner 34a to the end of the other side L2 of the crimped protrusion 17B1 (the boundary between the crimped protrusion 17B1 and the small diameter portion 16B) is defined as dimension α8. In this case, dimension α7 is preferably 0.5 times or more of dimension α8. This ensures a sufficient dimension in the axial direction L from the portion where the corner 34a is formed to the end of the one side L1 of the valve seat member 20B, thereby ensuring the strength of the one side L1 portion of the valve seat member 20B. This prevents deformation of the one side L1 portion of the valve seat member 20B, further improving the pull-out strength of the valve seat member 20B when the crimped protrusion 17B1 is engaged with the corner 34a.

[0073] The crimped portion 17B that bites into the corner 34a may be formed around the entire axis L as shown in FIG. 16(B) by roll crimping the outer periphery of the main body 10A where no crimped portion 17 is formed as shown in FIG. 16(A). However, it is more preferable to form the crimped portion 17B at a pinpoint location corresponding to the small diameter portion 16B by punch crimping as shown in FIG. 16(C). In this case, the crimped protrusion 17B1 is formed by the tip of the crimped portion 17B formed by punch crimping and protruding inward from the main body 10B. By forming the crimped portion 17B by punch crimping, stress generated in the crimped portion 17B can be reduced compared to a structure in which the entire periphery of the main body 10B is crimped, i.e., by so-called roll crimping.

[0074] This prevents the main body 10B from cracking and the resulting leakage of fluid to the outside. The crimped portion 17B formed by punch crimping can also be formed in one location to improve the holding force of the valve seat member 20B. However, from the perspective of ensuring a balance of strength around the entire circumference of the main body 10B, it is more preferable to form the crimped portions 17B at equal intervals, for example, in four or eight locations around the circumference of the main body 10B.

[0075] As shown in FIG. 15A , a flange portion 35B protruding radially outward toward the inner surface of the main body 10B is formed at the end of the other side L2 of the press-fit portion 33B of the valve seat member 20B. As shown in FIG. 17A , when the valve seat member 20B is press-fitted into the main body 10B, the flange portion 35B abuts against a boundary portion 10B1 between the large diameter portion 12B and the press-fit portion 14B on the inner surface of the main body 10B. At this time, a space is formed between the main body 10B and the valve seat member 20B, surrounded by the flange portion 35B, the press-fit portion 33B (the portion of the valve seat member 20B other than the flange portion 35B), and the press-fit portion 14B of the main body 10B. This space constitutes an oil reservoir 36 capable of storing oil 60 contained in the fluid flowing through the check valve 1B. 17B, ​​the flange portion 35B is formed with an oil inlet 37 that connects the oil reservoir 36 to the inside of the main body 10B. The oil inlet 37 is formed by a gap between the valve seat member 20B and the inner surface of the main body 10B, which is created by linearly cutting out part of the outer circumferential surface of the annular flange portion 35B.

[0076] Although the oil inlet 37 is formed by a notch in the third embodiment, the structure of the oil inlet 37 is not limited thereto. As shown in FIG. 17C , an inwardly recessed groove 38 may be formed in a portion of the outer peripheral surface of the annular flange 35B, and the groove 38 may be extended in the axial direction L to serve as the oil inlet. In this configuration, oil 60 contained in the fluid flowing through the main body 10B passes through the oil inlet 37 and enters the oil reservoir 36, where it is stored. 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 small gap or flaw between the press-fit margin 14B of the main body 10B and the press-fit portion 33B of the valve seat member 20B, the oil 60 supplied to the gap or flaw can more reliably prevent back leakage of the fluid. That is, the oil reservoir 36 and the oil introduction portion 37 constitute a working fluid leakage prevention portion that suppresses leakage of the fluid, similar to the portion biting into the corner portion 34a described above.

[0077] 17A, the oil 60 stored in the oil reservoir 36 is prevented from moving to the other side L2 by the flange abutment portion 35B1 where the flange portion 35B abuts against the main body 10B. Therefore, compared to a configuration in which an oil reservoir is simply formed by providing a gap between the valve seat member 20B and the main body 10B, the following can be suppressed: That is, the so-called ejector effect, in which the oil 60 is sucked out of the oil reservoir 36 due to being entrained in the fluid flow around the oil reservoir 36, can be prevented.

[0078] Next, a fourth embodiment will be described. FIG. 18 is a cross-sectional view of a check valve 1C according to the fourth embodiment, taken along the axis L. FIG. 19 is an enlarged view of region III in FIG. 18. The check valve 1C has a crimped portion 17C formed on one side L1 of the large-diameter portion 12C of the main body 10C. This crimped portion 17C is preferably formed by pinpointing the outer periphery of the main body 10A where the crimped portion 17C shown in FIG. 16(A) is not formed, by punch crimping as shown in FIG. 16(D). As shown in FIG. 19, the tip of the crimped portion 17C forms a crimped protrusion 17C1. The crimped portion 17C corresponds to the crimped portion 17B described above, and the crimped protrusion 17C1 corresponds to the crimped protrusion 17B1 described above. 19, the outer peripheral edge of the flange portion 35C of the valve seat member 20C forms a corner portion 35C1 having a surface 39 facing the other side L2 end portion of the valve seat member 20C. The crimping protrusion 17C1 bites into and engages with the corner portion 35C1.

[0079] In FIG. 19 , the symbol V2 indicates the amount of penetration of the crimped protrusion 17C1 into the corner 35C1. This penetration is represented by the distance between a line C3 perpendicular to a virtual line c3 drawn from the intersection of an imaginary line c1 along the outer peripheral surface of the main body 10C and a virtual line c2 perpendicular to the imaginary line c1 toward the vertex of the corner 35C1, and a line C4 parallel to the line C3 and tangent to the crimped protrusion 17C1. The penetration amount V2 is preferably set to approximately 1% to 20% of the thickness T3 of the large diameter portion 12C. This configuration allows the portion of the crimped protrusion 17C1 (the working fluid leakage prevention portion) that penetrates into the corner 35C1 to maintain sealing performance that adequately prevents back leakage, while suppressing deformation of the valve seat member 20C when it penetrates into the corner 35C1 and improving the pull-out strength of the valve seat member 20C.

[0080] Furthermore, according to the fourth embodiment, the working fluid leakage prevention portion can be configured by fitting the crimping protrusion 17C1 into the corner 35C1 of the flange portion 35C of the valve seat member 20C, eliminating the need to form the corner 34a of the annular recess 34B and allowing the annular recess 34B to be omitted. This allows the dimension of the valve seat member 20C in the axial direction L to be smaller than in a structure in which the annular recess 34B is formed. This also allows the check valve 1C to be made more compact, resulting in overall cost reductions.

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

Claims

1. A valve device comprising: a cylindrical main body extending from one side to the other side through which a fluid flows, a valve seat member pressed into said main body, and a valve disc opening and closing a valve port provided in said valve seat member, wherein the valve device further comprises: a press-fit portion provided on an outer surface of said valve seat member; and a press-fit portion provided on an inner surface of said main body with said press-fit portion in sliding contact with said one side from the other side, wherein a protruding surface portion protruding toward the inside of said main body is provided on said one side of the end of said other side of said press-fit portion, and a seal portion that prevents leakage of said fluid is formed by the close contact between said press-fit portion and said protruding surface portion.

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

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

4. The valve device according to claim 1, wherein the main body and the valve seat member are cylindrically formed, the pressed-in portion comprises a press-fit portion provided on the other side, a small diameter portion provided on the one side, and the protruding surface portion provided between the press-fit portion and the small diameter portion, the press-fit portion has an inner diameter dimension before the valve seat member is pressed into the valve seat member that is smaller than an outer diameter dimension of the press-fit portion in the valve seat member before being pressed into the valve seat member, the small diameter portion has an inner diameter dimension that is equal to or smaller than the inner diameter dimension of the press-fit portion, the other end of the protruding surface portion is continuous with the press-fit portion, and the one end of the protruding surface portion is continuous with the small diameter portion.

5. The valve device as described in claim 4, characterized in that a large diameter portion having an inner diameter larger than that of the press-fit portion is provided on the other side of the press-fit portion, the valve seat member is provided with a flange portion protruding toward the inner surface of the main body and abutting the boundary of the inner surface between the large diameter portion and the press-fit portion, a space surrounded by the flange portion and a portion of the valve seat member other than the flange portion and the press-fit portion of the main body constitutes an oil reservoir portion capable of storing oil contained in the fluid, the flange portion is provided with an oil introduction portion communicating the oil reservoir portion with the interior of the main body, and the oil reservoir portion and the oil introduction portion constitute a working fluid leakage prevention portion that suppresses leakage of the fluid.

6. The valve device according to claim 4, characterized in that the main body has a retention strength enhancing portion which enhances the retention strength of the pressed-in portion, the retention strength enhancing portion being constituted by the press-in portion which has been subjected to plastic working, and the thickness dimension of the press-in portion is smaller than the thickness dimension of the small diameter portion.

7. The valve device according to claim 4, wherein the outside diameter of said small diameter portion is equal to the outside diameter of said press-fit portion.

8. A valve device as described in claim 1, characterized in that the outer periphery of the valve seat member is provided with a corner having a surface facing the other end portion of the valve seat member, the main body is provided with a crimped portion which is crimped inwardly, and the crimped portion is provided with a crimping protrusion which engages with the corner portion.

9. A valve device according to claim 8, characterized in that the crimping protrusion is constituted by a tip of the crimping portion formed by punch crimping on the outer periphery of the main body and protruding inwardly from the main body.

10. A valve device as described in claim 8, characterized in that the crimping protrusion is engaged with at least a portion of the corner portion, and this engaged portion forms a working fluid leakage prevention portion that suppresses leakage of the fluid.

11. A valve device as described in claim 8, characterized in that an inwardly recessed annular recess is provided on said one side of the valve seat member, an end of said one side of the annular recess constitutes said corner, and the dimension from said one side end of the valve seat member to said corner in the axial direction of the body is 0.5 times or more the dimension from the corner to the other side end of the crimping protrusion.

12. A check valve comprising a valve device according to any one of claims 1 to 11.

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

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