Check valves and refrigeration cycle systems

Abstract

The objective is to provide a check valve that can overcome the conventional problem (decreased valve opening performance) even with a relatively small differential pressure in the valve opening direction by employing a valve body centering mechanism. [Solution] A check valve comprising: an outer tube portion 10; a valve seat portion 21 having a valve seat 21B and a valve port 21A; a valve holder portion 22 defining a valve chamber and having a cylindrical side wall portion 22A erected from the outer circumference of the valve seat 21B; a valve body 30A having a valve body side surface 32A that can contact the side wall portion 22A, a seal portion 31Aa provided only on one end surface 31A of the valve body, and a tapered portion 33A that narrows in diameter from the valve body side surface 32A to the seal portion 31Aa and connects to it; and a valve body centering means that, in a slightly open state, introduces primary pressure into an annular tapered space St defined by the tapered portion 33A, the radial extension of the seal portion 31Aa, and the side wall portion 22A, and allows movement in a direction perpendicular to the axis of the valve body 30A.

Description

Technical Field

[0001] The present invention relates to a check valve provided with a valve body centering means for centering the axis of the valve body on the axis of the valve body, and a refrigeration cycle system using the same.

Background Art

[0002] In a check valve, in the valve closed state, in addition to reliably preventing the reverse flow of fluid from the secondary side pipe to the primary side pipe, even when the differential pressure in the valve opening direction between the primary side pressure and the secondary side pressure is relatively small, it is required to quickly shift from the valve closed state to the valve open state and smoothly flow the fluid.

[0003] For example, in Patent Document 1, as shown in FIGS. 11(a) and (b), there is a vertically arranged check valve (hereinafter referred to as "conventional check valve") 1100, which includes a cylindrical outer pipe portion 1110 extending from a primary opening portion ##**1111C**## to a secondary opening portion ##**1112C**## along the axis L direction, a valve body 1120 housed in the outer pipe portion 1110, and a valve element 1130 provided on the valve body 1120.

[0004] This valve body 1120 is composed of a valve seat portion 1121 and a valve holder portion 1122. The valve seat portion 1121 includes a valve seat 112 **1B** on which the valve element 1130 can be seated, and a valve port 112 **1A** that defines the inner peripheral edge of the valve seat 112 **1B** and extends to one end side. Further, the valve holder portion 1122 includes a cylindrical side wall portion 112 **:** that stands upright from the outer peripheral side of the valve seat 112 **1B** and supports the valve element 1130 in a contactable manner, and a plurality of communication holes 112 **:** that penetrate the side wall portion 112 **:** in the radial direction and are evenly arranged in the circumferential direction. Further, a valve stopper 1140 for restricting the movement of the valve element 11 **:** in the other end side in the axis L direction of the valve body 1120 is provided on the inner peripheral surface of the other end side of the valve holder portion 1122.

[0005] Thus, in the conventional check valve 1100, the valve body 1130 is provided within the valve holder portion 1122 so as to be movable in the direction of the axis L between a valve closed state in which it is seated on the valve seat 1121B and a valve open state in which it is separated from the valve seat 1121B. Here, regardless of the mounting direction of the outer tube portion 1110 (for example, a vertical arrangement in which the axis L direction of the outer tube portion 1110 is aligned with the direction of gravity, or a horizontal arrangement in which it is aligned with a direction perpendicular to the direction of gravity), as shown in Figure 11(b), when the valve closed state the axis L1130 of the valve body 1130 is not coaxial with the axis L which is the axis of the valve body 1120, and the valve body side surface 1132A is in contact with the inner circumferential surface 1122Aa of the side wall, the static friction force and kinetic friction force of the valve body 1130 with respect to the side wall portion 1122A are relatively large.

[0006] Therefore, in such a situation, if the primary pressure P1 is slightly greater than the secondary pressure P2, and a relatively small differential pressure in the valve opening direction is generated in the valve body 1130, a relatively large drag force (static friction force and kinetic friction force) is generated due to the contact between the valve body side surface 1132A and the inner circumferential surface 1122Aa of the side wall. This may cause the valve body to not transition from the closed state to the open state, or it may take time to transition from the closed state to the open state, resulting in a decrease in responsiveness (hereinafter referred to as "conventional problem (decreased valve opening performance)").

[0007] In the conventional check valve 1100, when it is positioned horizontally and the valve is closed, the side surface 1132A of the valve body is in contact with the inner circumferential surface 1122Aa of the side wall (when Figure 11(b) is rotated 90° clockwise), the self-weight of the valve body 1130 is applied to the inner circumferential surface 1122Aa of the side wall. As a result, the static friction force and kinetic friction force become even greater compared to the vertical positioning, and the conventional problem (decreased valve opening performance) becomes more pronounced. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-159975 [Overview of the project] [Problems that the invention aims to solve]

[0009] The objective of the present invention is to provide a check valve that, regardless of whether it is vertically or horizontally positioned, can overcome the conventional problem (decreased valve opening performance) and improve reliability, even with a relatively small differential pressure in the valve opening direction, by employing a valve body centering means that centers the axis of the valve body towards the axis of the valve body. [Means for solving the problem]

[0010] To solve the above problems, a check valve is provided comprising: an outer tube portion extending along the axial direction and having a cylindrical shape; a valve body housed in the outer tube portion; a valve element provided so as to be able to abut against the valve body; and a valve element centering means for centering the axis of the valve element on the axis of the valve body, wherein the valve body comprises: a valve seat portion having a valve seat and a valve port; a valve holder portion defining a valve chamber and having a cylindrical side wall portion erected from the outer circumference of the valve seat; the valve element having a valve side surface that can abut against the side wall portion; a seal portion provided only on one end surface of the valve element; and a valve element that tapers in diameter from the valve side surface to the seal portion and contacts A check valve comprising a tapered portion, wherein the valve body is provided to be movable in the axial direction between a valve closed state in which the seal portion abuts against the valve seat and a valve open state in which the seal portion is separated from the valve seat and the valve port and the secondary internal space of the outer tube portion are in communication, and the valve body centering means enables movement of the valve body in a direction perpendicular to the axis of the valve body by introducing primary pressure into the annular tapered portion space defined by the tapered portion, the radial extension of the seal portion, and the side wall portion in a slightly open state in which the valve chamber and the valve port begin to communicate.

[0011] Furthermore, in the above-mentioned check valve, the valve body centering means may be configured such that the axial length of the tapered portion is greater than the radial length of the tapered portion.

[0012] Furthermore, in the above-mentioned check valve, the valve body centering means may be configured such that the length over which the valve body moves along the axial direction from the valve closed state to the state immediately before the valve opens is at least half the axial length of the tapered portion.

[0013] Furthermore, in the above-mentioned check valve, the valve body may have a weight-reducing hole that extends in the axial direction of the valve body but does not penetrate through it.

[0014] Furthermore, in the above-described check valve, a mortar-shaped recess may be formed on one end face of the valve body, coaxially with the valve body and recessed in a mortar shape toward the other end, and the sealing portion may be formed between the mortar-shaped recess and the tapered portion.

[0015] Furthermore, in the above-described check valve, one end face of the valve body may have a V-shaped projection coaxially with the valve body and projecting toward the one end, and an annular recess coaxially with the valve body and recessing toward the other end, with the seal portion formed between the annular recess and the tapered portion.

[0016] Furthermore, in the above-mentioned check valve, the axial length of the side wall portion is greater than the axial length of the valve body, and the side wall portion is provided with a plurality of communication holes at positions spaced apart from the valve seat, which connect the secondary internal space of the outer tube portion and the valve chamber in the radial direction, and the plurality of communication holes may be positioned opposite the side surface of the valve body from the valve closed state to the state just before the valve opens.

[0017] Furthermore, in the above-described check valve, when the valve is open and the axis of the valve body and the axis of the valve body are coaxially aligned, all of the intersections between the inner surface of the side wall and the other end of the plurality of communication holes may be located inside a virtual frustocone shape formed by virtually extending the tapered portion toward the other end, regardless of the axial position of the valve body.

[0018] Further, in the check valve, the axial length of the side wall portion may be smaller than the axial length of the valve body, and in the valve closed state, the other end surface of the side wall portion may be arranged at a position overlapping the side surface of the valve body when viewed from a direction perpendicular to the axis.

[0019] Further, it may be a refrigeration cycle system provided with the above check valve.

Effect of the Invention

[0020] According to the present invention, by adopting the valve body centering means for centering the axis of the valve body on the axis of the valve body, regardless of whether it is arranged vertically or horizontally, even with a relatively small differential pressure in the valve opening direction, the conventional problem (decrease in valve opening performance) can be solved, and a check valve capable of improving reliability can be provided.

Brief Description of the Drawings

[0021] [Figure 1] It is a longitudinal sectional view showing a check valve (valve closed state) according to a first embodiment of the present invention, where (a) is an overall view and (b) is a partially enlarged view of the valve body and the valve body in (a) (omitting the outer pipe portion). [Figure 2] It is a partially enlarged view with exaggerated gaps in the regions surrounded by the broken lines IIa, IIb, IIc, and IId shown in FIG. 1(a), where (a) represents the valve closed state, (b) represents the slightly open state, (c) represents the state immediately before valve opening, and (d) represents the valve open state. [Figure 3] It is an explanatory diagram of the centering action by the annular tapered portion space in the check valve shown in FIG. 1, where (a) is a partially enlarged view of the valve body and the valve body (omitting the outer pipe portion) (corresponding view of FIG. 1(b)), and (b) is a partially enlarged view with exaggerated gaps in the region surrounded by the broken line IIIb shown in (a) (corresponding view of FIG. 2(b)). [Figure 4] It is a longitudinal sectional view showing the check valve shown in FIG. 1 (valve open state), where (a) is an overall view (corresponding view of FIG. 1(a)), (b) is a partially enlarged view of the region surrounded by the broken line IVb shown in (a), and (c) is a sectional view taken along the line IVc-IVc shown in (a). [Figure 5] It is a diagram showing the refrigeration cycle system of the present invention. [Figure 6] It is an explanatory diagram (corresponding diagram of FIG. 1(b)) of a valve body modification example (valve closed state) in the first embodiment, where (a) represents valve body modification example 1 (mortar-shaped concave portion), and (b) represents valve body modification example 2 (mountain-shaped convex portion and annular concave portion). [Figure 7] It is a longitudinal sectional view showing a check valve (valve closed state) according to the second embodiment of the present invention, where (a) is an overall view (corresponding diagram of FIG. 1), (b) is a bottom view of the valve body shown in (a), (c) is a side view of the valve body shown in (a), and (d) is a top view of the valve body shown in (a). [Figure 8] It is a partially enlarged view (corresponding diagram of FIG. 2) with exaggerated gaps in the region surrounded by the broken lines VIIIa, VIIIb, VIIIc, and VIIId shown in FIG. 7(a), where (a) represents the valve closed state, (b) represents the slightly open state, (c) represents the state just before valve opening, and (d) represents the valve open state. [Figure 9] It is a longitudinal sectional view (corresponding diagram of FIG. 4(a)) showing the check valve (valve open state) shown in FIG. 7. [Figure 10] It is an explanatory diagram (corresponding diagram of FIG. 6) of a valve body modification example (valve closed state) in the second embodiment, where (a) represents valve body modification example {1} (mortar-shaped concave portion), and (b) represents valve body modification example 2 (mountain-shaped convex portion and annular concave portion). [Figure 11] It is a longitudinal sectional view showing a check valve (valve closed state) according to the prior art, where (a) is an overall view, and (b) is a partially enlarged view surrounded by the broken line XIb shown in (a).

Modes for Carrying Out the Invention

[0022] Embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10. However, the present invention is not limited to the aspects of this embodiment.

[0023] <Regarding Terms> In this specification and the claims, “left,” “right,” “up,” and “down” refer to the directions shown in Figures 1-3, 4(a),(b), 6, 7(a),(c), and 8-10. In this specification and the claims, “one end” and “the other end” refer to the “lower end” and “upper end” in the drawings. In this specification and the claims, “vertical arrangement” refers to an arrangement where the axial direction of the outer tube is aligned with the direction of gravity. In this specification and the claims, “horizontal arrangement” refers to an arrangement where the axial direction of the outer tube is aligned with a direction perpendicular to the direction of gravity. In this specification and the claims, “valve body centering means” refers to a means for centering the axis of the valve body with the axis of the valve body. In this specification and the claims, “annular” refers to a shape that is continuous and closed in the circumferential direction, including polygons, regardless of whether it is an annular shape. In this specification and the claims, “annular tapered space” means “an annular space defined by the tapered portion of the valve body, the radial extension of the seal portion of the valve body, and the side wall portion of the valve body.” In this specification and the claims, “valve closed state” means “a state in which the seal portion of the valve body abuts against the valve seat of the valve body and the flow of fluid is stopped.” In this specification and the claims, “slightly open state” means “a state in which the seal portion of the valve body separates from the valve seat of the valve body and the valve chamber and valve port begin to communicate.” In this specification and the claims, “state just before valve open” means “a state in which the seal portion of the valve body separates from the valve seat of the valve body and the valve chamber immediately before it communicates with the secondary internal space of the outer tube portion, either through a communication hole or directly.” In this specification and the claims, “valve open state” means “a state in which the sealing portion of the valve body is separated from the valve seat of the valve body, and the valve port communicates with the secondary internal space of the outer tube portion, either through the valve chamber and the communication hole, or directly from the valve chamber.” In this specification and the claims, “mortar-shaped” means “not only a conical shape, but also a polygonal pyramidal shape having a polygonal base, as it only needs to be concave in a mortar-like shape.” In this specification and the claims, “mountain-shaped” means “not only a conical shape, but also a polygonal pyramidal shape having a polygonal base, as it only needs to protrude in a mountain-like shape.”

[0024] (First embodiment) <Regarding the structure of the check valve> A check valve 100A according to the first embodiment of the present invention will be described using Figure 1. The check valve 100A consists of an outer tube portion 10, a valve body 20 housed in a secondary internal space, which is a housing chamber HC, within the outer tube portion 10, and a valve element 30A provided within the valve body 20 so as to be slidable in the direction of the axis L. The respective components of the check valve 100A will be described in order below. Here, in the check valve 100A according to the first embodiment, a vertical arrangement is used as an example for explanation purposes, but it is not limited to this and includes other arrangements such as a horizontal arrangement. Note that the horizontal arrangement differs from the vertical arrangement only in that the self-gravity of the valve element 30A acts in a direction perpendicular to the axis L, so the explanation of the horizontal arrangement is omitted here.

[0025] As will be explained in more detail later, in the first embodiment, by employing a valve body centering means (1) (introducing primary side pressure into the annular tapered space), it is possible to overcome the conventional problem (decreased valve opening performance) and improve reliability, even with a relatively small differential pressure in the valve opening direction, regardless of whether the valve is vertically or horizontally positioned.

[0026] <About the outer tubing> The outer tube portion 10 is made of a metal material such as copper, has a cylindrical shape extending in the axial direction L, and is integrally formed by drawing or the like. The outer tube portion 10 includes a primary joint portion 11 extending to one end, a secondary joint portion 12 extending to the other end, and a valve body housing portion 13 continuously connected between the primary joint portion 11 and the secondary joint portion 12.

[0027] The primary joint 11 includes a cylindrical primary cylindrical portion 11A, a first connecting portion 11B that expands in diameter from the primary cylindrical portion 11A, and a primary opening 11C that is connected to a primary pipe (not shown) and into which the primary side pressure P1 is introduced.

[0028] The secondary joint section 12 includes a cylindrical secondary cylindrical section 12A, a second connecting section 12B that expands in diameter from the secondary cylindrical section 12A, and a secondary opening 12C that is connected to a secondary pipe (not shown) and into which the secondary pressure P2 is introduced.

[0029] The valve body housing portion 13 has a first enlarged diameter portion 13A that is continuously enlarged from the primary joint portion 11, a second enlarged diameter portion 13B that is enlarged more than the first enlarged diameter portion 13A and is continuous with the secondary joint portion 12, and a stepped portion 13C at the boundary between the first enlarged diameter portion 13A and the second enlarged diameter portion 13B.

[0030] The first enlarged diameter portion 13A is the part that holds the valve body 20 located inside, and fixing portions 13D are formed at multiple locations on the circumferential surface, which deform radially inward to fix the valve body 20. As will be described in detail later, these fixing portions 13D are crimped and deformed by a punch of a press device and engage with the constricted portion 21C of the valve body 20, thereby fixing the valve body 20 in a predetermined position inside the outer tube portion 10.

[0031] In the first embodiment, the primary joint 11, the secondary joint 12, and the valve body housing 13 are integrally molded, but the invention is not limited to this. For example, they may be molded separately and then assembled using screw fixing or welding. Also, in the first embodiment, press-fitting and crimping are used to fix the valve body 20 inside the outer tube 10, but the invention is not limited to this. For example, press-fitting only, crimping only, screw fixing, welding, or adhesive fixing may be used.

[0032] <About the valve body> The valve body 20 is made of a metal material such as brass and is formed by machining or other processes. As shown in Figure 1(b), the valve body 20 comprises a valve seat portion 21 and a valve holder portion 22.

[0033] The valve seat portion 21 has a valve port 21A having a circular cross-section that penetrates along the axis L, and a valve seat 21B formed flat on the peripheral edge of the other end of the valve port 21A, on which the valve body 30A can be seated. Furthermore, an annular throttling portion 21C is formed on the outer surface of one end of the valve seat portion 21, and a radially projecting flange portion 21D is formed on the outer surface of the other end of the valve seat portion 21. By press-fitting the valve body 20 into the first enlarged diameter portion 13A until this flange portion 21D abuts against the inner surface of the stepped portion 13C of the outer tube portion 10, the valve body 20 is positioned relative to the outer tube portion 10, and the valve body 20 is fixed relative to the outer tube portion 10 by the engagement of the fixing portion 13D of the outer tube portion 10 with the annular throttling portion 21C.

[0034] In the first embodiment, the shape of the valve port 21A is a circular cross-sectional shape, but it is not limited to this, and may be an elliptical cross-sectional shape, a polygonal cross-sectional shape, or the like.

[0035] The valve holder portion 22 is erected on the other end side of the outer circumference of the valve seat 21B and has a cylindrical side wall portion 22A that defines a valve chamber VC (see Figure 4(a)) on its inside, a plurality of (e.g., two) communication holes 22B that penetrate the side wall portion 22A radially at a position spaced apart from the valve seat 21B, and an annular groove portion 22C provided on the other end side of the inner circumferential surface 22Aa (inner circumferential surface of the side wall portion). These plurality of communication holes 22B are arranged axially symmetrically when viewed from the direction of the axis L. Furthermore, the length of the side wall portion 22A in the direction of the axis L is greater than the length of the valve body 30A in the direction of the axis L. In addition, a valve stopper 40 is provided in the annular groove portion 22C to restrict the movement of the valve body 30A to the other end side (see Figure 4(a)). The valve stopper 40 is made of stainless steel and has a retaining ring (e.g., a C-ring) shape. It is compressed radially and inserted into the annular groove 22C, and then released to be housed in the annular groove 22C. Furthermore, the outer diameter of the valve holder 22 is set to be smaller than the inner diameter of the second enlarged diameter 13B so that fluid flows in the axial direction L through the radial gap between the valve holder 22 and the second enlarged diameter 13B.

[0036] In the first embodiment, the communication holes 22B are arranged axially in pairs, as shown in Figure 4(a), but the number and arrangement are not limited to this and can be changed as needed.

[0037] <About the valve body> The valve body 30A is made of a high-strength resin material such as polyetheretherketone (PEEK) and has a substantially cylindrical shape centered on an axis L30A parallel to the axis L direction. This configuration makes it possible to reduce the weight of the valve body 30A while maintaining strength compared to metal materials. The valve body 30A has one end face 31A which is a flat disc shape and a side face 32A (side face) which is a cylindrical outer curved surface.

[0038] The valve body end face 31A has a flat, annular sealing portion 31Aa on its radial outer edge, and this sealing portion 31Aa abuts against the flat, annular valve seat 21B. Therefore, the outer diameter of the valve body end face 31A is set to be larger than the inner diameter of the valve seat 21B, that is, the inner diameter of the valve port 21A. In addition, the outer diameter of the valve body side surface 32A is set to be slightly smaller than the inner diameter of the inner circumferential surface 22Aa of the side wall 22A, so that the valve body 30A can slide within the side wall 22A in the axial direction L. As a result, if the check valve 100A is installed immediately after the compressor 600 or immediately after a curved pipe in the refrigeration cycle system 1000 described later, even if a swirling component is present in the fluid, it is possible to prevent the swirling flow from flowing between the inner circumferential surface 22Aa of the side wall and the side surface 32A of the valve body, thereby suppressing the rotation of the valve body 30A and reducing the generation of abnormal noise and wear of the valve body caused by the rotation of the valve body 30A.

[0039] Furthermore, as shown in Figure 2(a), the valve body 30A has a tapered portion 33A between the valve body side surface 32A and the seal portion 31Aa, which tapers in diameter from the valve body side surface 32A to the seal portion 31Aa.

[0040] In the first embodiment, the longitudinal cross-sectional shape of the tapered portion 33A was a straight line, but it is not limited to this, and for example, the longitudinal cross-sectional shape may be a curved shape that narrows in diameter from the valve body side surface 32A to the seal portion 31Aa.

[0041] <About Refrigeration Cycle Systems> As shown in Figure 5, the check valve 100A can be used in a refrigeration cycle system 1000 (for example, an air conditioner such as a commercial air conditioner).

[0042] This refrigeration cycle system 1000 consists of an indoor heat exchanger 200, an outdoor heat exchanger 300, an expansion valve 400, a four-way valve 500, and three compressors 600 connected in parallel, each connected via piping. A check valve 100A is connected between the discharge (high pressure) side of each compressor 600 and the four-way valve 500 to prevent backflow of refrigerant to each compressor 600, with the compressor 600 as the primary side and the four-way valve 500 as the secondary side. Accumulators, pressure sensors, temperature sensors, etc., are not shown in the diagram.

[0043] The flow path of the refrigeration cycle can be switched between two modes by the four-way valve 500: one for cooling operation and one for heating operation. During cooling operation (see solid arrow in Figure 5), the refrigerant compressed by the compressor 600 circulates through the check valve 100A, then through the four-way valve 500 to the outdoor heat exchanger 300, expansion valve 400, indoor heat exchanger 200, four-way valve 500, and finally back to the compressor 600. The outdoor heat exchanger 300 functions as a condenser, and the indoor heat exchanger 200 functions as an evaporator.

[0044] On the other hand, during heating operation (see dashed arrow in Figure 5), the refrigerant compressed by the compressor 600 is circulated via the check valve 100A through the four-way valve 500, then through the indoor heat exchanger 200, expansion valve 400, outdoor heat exchanger 300, four-way valve 500, and finally back to the compressor 600. The indoor heat exchanger 200 functions as a condenser, and the outdoor heat exchanger 300 functions as an evaporator.

[0045] Here, for example, under conditions where the cooling load is large, in order to operate the three compressors 600 simultaneously, each of the three check valves 100A is in a fully open state. Also, under conditions where the cooling load is small, since only the operation of one compressor 600 is sufficient, the other two compressors 600 do not operate. At this time, the secondary-side pressure of the two check valves 100A becomes higher than the primary-side pressure, causing a reverse flow from the secondary side, and the two check valves 100A are in a closed state.

[0046] In addition, in this embodiment, although an air conditioner such as a commercial air conditioner is used as the refrigeration cycle system for explanation, it is not limited to this, and an air conditioner such as a household air conditioner may also be used, and it is not limited to air conditioners, and it is also applicable to various refrigerators and the like.

[0047] <Regarding the operation of the check valve> The operation of the check valve 100A will be described using FIGS. 1(a) and FIGS. 4(a). Here, as shown in FIG. 5, a compressor 600, which is a pressure supply source, is connected to the primary joint portion 11, and the indoor-side heat exchanger 200 and the outdoor-side heat exchanger 300, which are heat loads, are connected to the secondary joint portion 12 via the four-way valve 500. As an initial state, the primary-side pressure P1 is made smaller than the secondary-side pressure P2 (P1 < P2). Here, for convenience of explanation, a vertically arranged check valve 100A is used, but it is not limited to this, and it includes other arrangements such as a horizontally arranged one. Also, here, in common with the vertical and horizontal arrangements, attention is paid to the differential pressure in the valve opening and closing directions, which is the force acting on the valve body 30A, and the description of the action of the self-weight of the valve body 30A is omitted. In the first embodiment, since there is no biasing member that biases the valve body 30A in the valve closing direction, even a relatively small differential pressure in the valve opening direction (P1 - P2) improves the valve opening performance.

[0048] First, as shown in FIG. 1(a), when the valve body 30A is seated on the valve seat 21B and the seal portion 31Aa is in contact with the valve seat 21B in the valve closed state, when the primary-side pressure P1 and the secondary-side pressure P2 (< P1) are respectively applied to one end side and the other end side of the valve body 30A, a differential pressure in the valve opening direction (P1 - P2) is generated in the valve body 30A.

[0049] When the differential pressure (P1 - P2) in the valve opening direction exceeds a predetermined threshold value, as shown in Fig. 4(a), the valve body 30A separates from the valve seat 21B and enters the valve open state. In this valve open state, the fluid flowing into the valve chamber VC from the primary opening 11C through the valve port 21A is once branched into a plurality of communication holes 22B provided in the side wall portion 22A. Then, the branched fluid passes through the radial gaps between the outer peripheral surface of the valve holder portion 22 and the inner peripheral surface of the outer pipe portion 10, respectively, and after rejoining in the accommodation chamber HC of the outer pipe portion 10, it flows to the secondary opening 12C on the other end side in the direction of the axis L.

[0050] In this valve open state, when the differential pressure (P1 - P2) in the valve opening direction applied to the valve body 30A is relatively large, as shown in Fig. 4(a), the valve body 30A continues to move toward the other end side within the valve holder portion 22. Finally, when the other end surface of the valve body 30A abuts against the valve stopper 40, the movement toward the other end side is restricted.

[0051] After that, when the primary pressure P1 becomes smaller than the secondary pressure P2 (P1 < P2) due to a pressure drop in the pressure supply source or the like, a differential pressure (P2 - P1) in the valve closing direction is generated on the valve body 30A, and the valve body 30A returns to the valve closed state of seating on the valve seat 21B, preventing backflow from the secondary opening 12C to the primary opening 11C.

[0052] <Regarding the conventional problem (decrease in valve opening performance)> As described above, in the conventional check valve 1100 shown in Fig. 11(b), when a relatively small differential pressure in the valve opening direction is generated on the valve body 1130, due to the relatively large resistance force (static friction force and dynamic friction force) generated by the contact between the valve body side surface 1132A and the inner peripheral surface of the side wall 1122Aa, it has the conventional problem (decrease in valve opening performance). <000,0209>

[0053] In contrast, in the first embodiment, by employing a valve body centering means (1) (introducing primary side pressure into the annular tapered space), it is possible to overcome the conventional problem (decreased valve opening performance) and improve reliability, even with a relatively small differential pressure in the valve opening direction, regardless of whether the valve is vertically or horizontally positioned.

[0054] <Regarding valve body centering means (1) (introduction of primary side pressure into the annular tapered space)> Using Figures 2 and 3, the valve body centering means (1) (introduction of primary side pressure into the annular tapered space) will be explained. Here, as shown in Figure 2(a), in the valve closed state, the right side of the valve body side surface 32A is in contact with the side wall portion 22A. Note that the gap between the valve seat 21B and the seal portion 31Aa, and the gap between the inner circumferential surface of the side wall 22Aa and the valve body side surface 32A, shown in Figures 2(b) to (d) and Figure 3(b), are exaggerated for the sake of understanding. Also, as shown in Figures 2(b) to (c) and Figure 3(b), in the state from the slightly open state to the state just before valve opening, the fluid velocity is extremely slow, so static pressure becomes dominant over dynamic pressure.

[0055] First, in the valve closed state shown in Figure 2(a), where the seal portion 31Aa abuts against the valve seat 21B, the tapered portion 33A, the radial extension of the seal portion 31Aa of the valve body 30A, and the side wall portion 22A define an annular tapered space St that is continuous in the circumferential direction when viewed from the direction of the axis L. If the axis L30A of the valve body 30A is coaxial with the axis L of the valve body 20, the same radial gap is formed between the valve body side surface 32A and the side wall portion 22A along the circumferential direction. Here, as shown in Figure 1(b), the valve body 30A is eccentric with respect to the valve body 20, with the right side of the valve body side surface 32A in contact with the inner circumferential surface 22Aa of the side wall, while the left side of the valve body side surface 32A is separated from the inner circumferential surface 22Aa of the side wall.

[0056] Next, in the slightly open state shown in Figure 2(b), when the valve chamber VC and the valve port 21A begin to communicate, the valve body centering means (1) (introduction of primary side pressure into the annular tapered space) introduces the primary side pressure P1 into the annular tapered space St via the valve chamber VC, and a small amount of fluid is discharged from the annular tapered space St to the secondary side. This valve body centering means (1) (introduction of primary side pressure into the annular tapered space) will be described in detail below, but it can apply a pressing force (radial pressing force Ftr) to the valve body 30A in a direction perpendicular to the axis L.

[0057] First, as shown in Figure 3(a), in the large radial gap region GL (see Figure 3(a)), where the radial gap between the valve body 30A and the side wall portion 22A is relatively large when viewed from the direction of axis L, fluid pressure easily escapes to the secondary side, resulting in a locally low pressure in the annular tapered space St. Conversely, in the small radial gap region GS (see Figure 3(a)), where the radial gap between the valve body 30A and the side wall portion 22A is relatively small (or zero), fluid pressure is less likely to escape to the secondary side, resulting in a locally high pressure in the annular tapered space St. As a result, a non-uniform pressure distribution occurs in the annular tapered space St along the circumferential direction when viewed from the direction of axis L.

[0058] Here, as shown in Figures 3(a) and 3(b), a pressing force Ft is generated in the tapered portion 33A due to the fluid pressure in the annular tapered portion space St, which presses the tapered portion 33A in the vertical direction. This pressing force Ft can be divided into an axial pressing force Ftl directed in the direction of the axis L and a radial pressing force Ftr directed in the radial direction.

[0059] Therefore, as shown in Figure 3(a), due to the non-uniform pressure distribution in the circumferential direction that occurs in the annular tapered space St, a centripetal force, which is a relatively large radial pressure Ftr, is generated in the region with a small radial gap GS compared to the region with a large radial gap GL.

[0060] As a result, the centripetal force, which is the sum of the non-uniform radial pressing forces Ftr in the circumferential direction, acts on the valve body 30A such that the radial gap between the valve body 30A and the side wall portion 22A becomes uniform in the circumferential direction, that is, the axis L30A of the valve body 30A becomes coaxial with the axis L of the valve body 20. Here, an axial pressing force Ftl acts on the valve body 30A, so the valve body 30A moves in the valve opening direction while being radially centered (see M1 in Figure 2(b)).

[0061] Furthermore, due to the non-uniform pressure distribution in the circumferential direction within the annular tapered space St, a relatively large axial pressure Ftl is generated in the small radial gap region GS compared to the large radial gap region GL. However, as shown in Figure 3(a), in the region of the valve body 30A facing the valve port 21A on one end face 31A, a primary side pressure P1 is applied, resulting in an upward axial pressure that is significantly larger than the sum of the axial pressures Ftl generated throughout the annular tapered space St. Therefore, the influence of the axial pressure Ftl generated throughout the annular tapered space St can be ignored.

[0062] Furthermore, in the state just before valve opening, as shown in Figure 2(c), when the annular tapered space St and the communication hole 22B begin to communicate, the valve body 30A is still moved in the valve opening direction while being radially centered by the valve body centering means (1) (introduction of primary side pressure into the annular tapered space). Note that in Figure 2(c), between the slightly open state and the state just before valve opening, the axis L30A of the valve body 30A becomes coaxial with the axis L of the valve body 20, so the valve body 30A moves in the valve opening direction without contacting the side wall portion 22A (see M2 in Figure 2(c)).

[0063] Then, in the valve-open state shown in Figure 2(d), where the annular tapered space St disappears and the valve chamber VC and the housing chamber HC communicate through the communication holes 22B, the fluid flowing from the valve port 21A into the valve chamber VC flows through the gap between the tapered portion 33A and the inner circumferential surface 22Aa of the side wall toward the multiple communication holes 22B that are evenly spaced in the circumferential direction. At this time, although the annular tapered space St disappears and the centripetal force due to the radial pressing force Ftr disappears, the primary side pressure P1 is still applied to one end face 31A of the valve body, so the valve body 30A can continue to move toward the valve-opening direction (see M3 in Figure 2(d)).

[0064] Here, as shown in Figure 4(a), when the differential pressure (P1'-P2') applied to the valve body 30A in the valve opening direction is relatively large, the valve body 30A continues to move toward the other end within the valve holder portion 22. However, its movement toward the other end is eventually restricted when the other end surface of the valve body 30A comes into contact with the valve stopper 40. In this case, as shown in Figures 4(b) and (c), when the axis L30A of the valve body 30A and the axis L of the valve body 20 are arranged coaxially, all of the intersection points P between the inner circumferential surface 22Aa of the side wall and the other end 22Bb of the multiple communication holes 22B are located inside the virtual frustocone shape (see the dashed line extending from 33A in Figure 4(b)) formed by virtually extending the tapered portion 33A toward the other end. As a result, when the valve is open, as the fluid collides with one end face 31A of the valve body and moves radially outward, the fluid is guided along the tapered portion 33A, allowing it to flow smoothly into the radial gap between the outer surface of the valve holder portion 22 and the inner surface of the outer tube portion 10 without passing through a flow path that causes pressure loss (the gap between the inner circumferential surface 22Aa of the side wall, where intersection P is the inlet, and the side surface 32A of the valve body) (see Fl in Figure 4(b)). Furthermore, when a swirling component is present in the fluid, the inflow of the swirling flow into the space between the inner circumferential surface 22Aa of the side wall and the side surface 32A of the valve body can be prevented, suppressing the rotation of the valve body 30A, and further reducing the generation of abnormal noise and wear of the valve body due to the rotation of the valve body 30A.

[0065] Thus, in the first embodiment, by employing a valve body centering means (1) (introduction of primary side pressure into the annular tapered space), the axis L30A of the valve body 30A becomes coaxial with the axis L of the valve body 20 between the slightly open state and the state just before valve opening. As a result, the valve body 30A can move in the valve opening direction without contacting the side wall portion 22A, thus eliminating the conventional problem (decreased valve opening performance) and improving reliability.

[0066] Furthermore, through diligent research, the inventor attempted to more reliably center the axis L30A of the valve body 30A towards the axis L of the valve body 20 by further employing at least one of the following: valve body centering means (2) (increase in radial pressing force), valve body centering means (3) (increase in the travel length over which the radial pressing force acts), and valve body centering means (4) (lightening of the valve body).

[0067] <Regarding valve body centering means (2) (increase in radial pressing force)> The valve body centering means (2) (increase in radial pressing force) is made larger than the radial length b of the tapered portion 33A, as shown in Figure 2(a) (1

[0068] As a result, as shown in Figure 3(b), the direction of the pressing force Ft applied to the tapered portion 33A can be more actively directed radially, that is, the radial pressing force Ftr can be made greater than the axial pressing force Ftl. Therefore, the centripetal force, which is the sum of the radial pressing forces Ftr acting on the valve body 30A, can be increased, and the axis L30A of the valve body 30A can be more reliably centered on the axis L of the valve body 20 between the slightly open state and the state just before valve opening. It is preferable to set 5≦a / b in order to reliably increase the radial pressing force Ftr.

[0069] <Regarding valve body centering means (3) (large travel length under radial pressure)> ​The valve body centering means (3) (large length of movement under radial pressure) is such that, as shown in Figure 2(a), the length c by which the valve body 30A moves along the axis L from the closed state to the state just before the valve opens is at least half of the length a of the tapered portion 33A in the axis L direction (0.5 ≤ c / a). In other words, the length c by which the valve body 30A moves along the axis L from the closed state to the state just before the valve opens is the length in the axis L direction between the other end of the tapered portion 33A and the end 22Ba of the communication hole in the closed state.

[0070] This creates an annular tapered space St, which increases the length over which the valve body 30A moves along the axis L when subjected to the radial pressing force Ftr. In other words, it increases the length over which the valve body 30A moves along the axis L from the slightly open state to the state just before valve opening (see Figures 2(b) and 2(c)). This allows the axis L30A of the valve body 30A to be more reliably centered on the axis L of the valve body 20. However, if the length over which the valve body 30A moves along the axis L when subjected to the radial pressing force Ftr is made too long, the time from the valve closed state to the valve open state will increase, which may lead to a decrease in responsiveness. Therefore, it is preferable to set it to 0.5 ≤ c / a ≤ 0.9.

[0071] <Regarding valve body centering means (4) (lightweighting of the valve body)> The valve body centering means (4) (lightweighting of the valve body) is provided in the valve body 30A as shown in Figure 1(b), by providing a weight-reducing hole 34A in the valve body 30A that runs from the center of the other end face toward the one end face along the axis L30A of the valve body 30A, without penetrating through. By making the valve body 30A lighter, even if a small centripetal force acts on the valve body 30A due to a relatively small differential pressure in the valve opening direction (P1'-P2') between the slightly open state and the state just before valve opening, the axis L30A of the valve body 30A can be more reliably centered toward the axis L of the valve body 20.

[0072] Thus, in the first embodiment, in addition to valve body centering means (1) (introduction of primary side pressure into the annular tapered space), by further employing at least one of valve body centering means (2) (increase in radial pressing force), valve body centering means (3) (increase in the travel length over which the radial pressing force acts), and valve body centering means (4) (lightening of the valve body), the axis L30A of the valve body 30A can be more reliably centered on the axis L of the valve body 20.

[0073] (Valve body modification) Here, using Figure 6, modified valve body 1 and 2 of the first embodiment will be described. Modified valve body 1 and 2 differ from the first embodiment in that the shape of one end face 31A', 31A'' of the valve body is not a flat surface, but the other basic configurations are the same as those of the first embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0074] <Regarding concerns (inhibition of smooth movement due to valve tilt during valve centering)> In the valve body 30A of the first embodiment, the shape of one end face 31A of the valve body is a flat surface, and therefore it is likely to be affected by dynamic pressure to some extent. Specifically, when the fluid collides with the flat end face 31A of the valve body through the valve port 21A between the slightly open state and the state just before the valve opens (see Figures 2(b) and (c)), three-dimensional turbulence occurs in the fluid after the collision. As a result, the end face 31A of the valve body is subjected to dynamic pressure that is transient and has a non-uniform distribution when viewed from the direction of the axis L. Therefore, due to this dynamic pressure, if the axis L30A of the valve body 30A is eccentric and inclined with respect to the axis L of the valve body 20, the outer peripheral edge of the other end of the valve body 30A will come into contact with the inner peripheral surface 22Aa of the side wall in a scratching manner, which raises concerns that this will suppress the smooth movement of the valve body 30A in the radial direction and valve opening direction due to the centripetal action (hereinafter referred to as "concern (suppression of smooth movement due to valve body inclination when valve body is centripetal)").

[0075] In contrast, in the modified valve body of the first embodiment, by further employing the valve body centering means (5) (suppression of valve body tilting during valve body centering: recess) in modified valve body 1, or the valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) in modified valve body 2, the concern (suppression of smooth movement due to valve body tilting during valve body centering) can be resolved.

[0076] <Regarding valve body centering means (5) (Suppression of valve body tilting during valve body centering: recess)> Using Figure 6(a), the valve body centering means (5) (recess for suppressing valve body tilting during valve body centering) in modified valve body 1 of the first embodiment will be explained. This valve body centering means (5) (recess for suppressing valve body tilting during valve body centering) has a mortar-shaped recess 31Ab' formed on one end face 31A' of the valve body, coaxial with the valve body 30A' and recessed in a mortar shape toward the other end, and the sealing portion 31Aa' is formed between the mortar-shaped recess 31Ab' and the tapered portion 33A. As a result, the fluid in the mortar-shaped recess 31Ab' remains stagnant at least while the centering action on the valve body 30A' is acting (at least from the slightly open state to the state just before valve opening). Therefore, a static pressure that is constant and uniformly distributed when viewed from the direction of the axis L is applied to one end face 31A' of the valve body. As a result, the tilt of the axis of the valve body 30A' with respect to the axis L of the valve body 20 can be suppressed, and the concern (suppression of smooth movement due to the tilt of the valve body when it is centered) can be eliminated.

[0077] In addition, the mortar-shaped recess 31Ab' of the modified valve body 1 is a cone shape with a circular base, but it is not limited to this, as long as it is recessed in a mortar shape, it may also be a polygonal pyramidal shape with a polygonal base, for example.

[0078] <Regarding valve body centering means (6) (Suppression of valve body tilting during valve body centering: recessed and convex parts)> Using Figure 6(b), the valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) in the modified valve body 2 of the first embodiment will be explained. This valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) has a V-shaped protrusion 31Ac'' that protrudes in a V-shape toward one end side coaxially with the valve body 30A'' on one end face 31A'' of the valve body, and an annular recess 31Ab'' that is recessed in an annular shape toward the other end side coaxially with the valve body 30A'' around the V-shaped protrusion 31Ac'', and the seal portion 31Aa' is formed between the annular recess 31Ab'' and the tapered portion 33A. As a result, at least while a centripetal force is acting on the valve body 30A'' (at least from the slightly open state to the state just before valve opening), when the fluid collides with one end face 31A'' of the valve body via the valve port 21A, the fluid flows smoothly radially outward after the collision due to the rectifying effect of the V-shaped protrusion 31Ac''. Therefore, a dynamic pressure that is a steady change and has a uniform distribution in the circumferential direction when viewed from the direction of the axis L is applied to one end face 31A''. In addition, since the fluid in the annular recess 31Ab'' is stagnant, a static pressure that is a steady change and has a uniform distribution in the circumferential direction when viewed from the direction of the axis L is applied to one end face 31A''. As a result, the inclination of the axis of the valve body 30A'' with respect to the axis L of the valve body 20 can be suppressed, and as a result, the concern (suppression of smooth movement due to the inclination of the valve body when it is centripetal) can be eliminated.

[0079] In addition, the V-shaped protrusion 31Ac'' of the modified valve body 2 is a cone shape with a circular base, but it is not limited to this, as it only needs to protrude in a V-shape, so for example it may be a polygonal pyramidal shape with a polygonal base.

[0080] As described above, in the first embodiment and valve body modifications 1 and 2, by employing the valve body centering means (1) (introduction of primary side pressure into the annular tapered space), regardless of whether the valve is vertically or horizontally positioned, it is possible to overcome the conventional problem (decreased valve opening performance) and improve reliability, even with a relatively small differential pressure in the valve opening direction.

[0081] Furthermore, in the first embodiment and valve body modifications 1 and 2, by further employing at least one of the valve body centering means (2) (increase in radial pressing force), valve body centering means (3) (increase in the travel length over which the radial pressing force acts), and valve body centering means (4) (lightening of the valve body), the axis L30A of the valve bodies 30A, 30A', and 30A'' can be more reliably centered on the axis L of the valve body 20.

[0082] Furthermore, by making the outer diameter of the valve body side surface 32A slightly smaller than the inner diameter of the inner circumferential surface 22Aa of the side wall 22A, the valve body 30A can slide within the side wall 22A in the axial direction L. This prevents the swirling flow from entering the space between the side wall 22A and the valve body side surface 32A, thereby suppressing the rotation of the valve body 30A and reducing the generation of abnormal noise and wear of the valve body caused by the rotation of the valve body 30A.

[0083] In addition, in the first embodiment and valve body modifications 1 and 2, when the valve is open, the axes L30A of the valve bodies 30A, 30A', and 30A'' and the axis L of the valve body 20 are coaxially arranged, and all of the intersection points P between the inner circumferential surface 22Aa of the side wall and the other end 22Bb of the multiple communication holes 22B are located inside the virtual frustocone shape formed by the tapered portion 33A. As a result, the fluid is guided along the tapered portion 33A and can flow smoothly without passing through a flow path that causes pressure loss. Furthermore, it prevents the inflow of swirling flow between the side wall portion 22A and the valve body side surface 32A, suppressing the rotation of the valve body 30A, and further reducing the generation of abnormal noise and wear of the valve body due to the rotation of the valve body 30A.

[0084] Furthermore, by further employing the valve body centering means (5) (recessed portion to suppress valve body tilting during valve body centering) in valve body modification 1, or the valve body centering means (6) (recessed portion and convex portion to suppress valve body tilting during valve body centering) in valve body modification 2, the concern (suppression of smooth movement due to valve body tilting during valve body centering) can be resolved.

[0085] (Second embodiment) The check valve 100B according to the second embodiment will be described with reference to Figure 7. The check valve 100B according to the second embodiment differs from the check valve 100A of the first embodiment mainly in the configuration of the valve holder portion 22' of the valve body 20' and the valve element 30B, and in the provision of a valve stopper 40' on the outer tube portion 10. However, the other basic configurations are substantially the same as those of the first embodiment. Here, identical components are denoted by the same reference numerals, and redundant explanations are omitted.

[0086] <Regarding concerns (reduced responsiveness due to burr effects)> In the first embodiment, as shown in Figure 1(b), a communication hole 22B is opened in the side wall portion 22A, which communicates with the containment chamber HC, which is the secondary internal space. Since this communication hole 22B is formed by drilling a hole from a direction perpendicular to the axis L relative to the side wall portion 22A, burrs protruding radially inward are generated on the inner edge of this communication hole 22B. For this reason, deburring is performed on the communication hole 22B, but there was a possibility that slight unevenness would remain on the inner edge of the communication hole 22B after deburring, when viewed at a microscopic level.

[0087] Therefore, when the valve body 30A is in contact with the side wall portion 22A including the communication hole 22B in the closed state, the static friction force and dynamic friction force of the valve body 30A against the side wall portion 22A increase slightly due to the effect of microscopic undulations remaining on the inner edge of the communication hole 22B, raising concerns that the responsiveness of the transition from the closed state to the open state will decrease (hereinafter referred to as "concern (decreased responsiveness due to the effect of burrs)").

[0088] In contrast, in the second embodiment, similar to the first embodiment, by employing a valve body centering means (1) (introducing primary side pressure into the annular tapered space), the conventional problem (decreased valve opening performance) can be resolved and reliability improved, even with a relatively small differential pressure in the valve opening direction, regardless of whether the valve is vertically or horizontally positioned. In addition, as will be described in detail later, the length of the side wall portion 22A' in the axial direction L is made smaller than the length of the valve body 30B in the axial direction L, so as to omit the communication hole, and in the valve closed state, the other end face of the side wall 22Ab' is positioned to overlap with the valve body side surface 32B when viewed from a direction perpendicular to the axis L, thereby resolving the concern (decreased responsiveness due to the effect of burrs).

[0089] <Regarding the structure of the check valve> The check valve 100B consists of an outer tube portion 10, a valve body 20' housed in a secondary internal space called a housing chamber HC within the outer tube portion 10, and a valve element 30B that is slidably mounted within the outer tube portion 10 and the valve body 20' in the axial direction L. The components of the check valve 100B will be described in order below. The second embodiment, like the first embodiment, includes not only vertical arrangements but also other arrangements such as horizontal arrangements.

[0090] <About the outer tubing> The outer tube portion 10 has the same configuration as the first embodiment, so its description is omitted. The inner circumferential surface of the second connecting portion 12B functions as a valve stopper 40' that restricts the movement of the valve body 30B toward the other end in the axial direction L.

[0091] In the second embodiment, similar to the first embodiment, the primary joint 11, the secondary joint 12, and the valve body housing 13 are integrally molded, but are not limited to this. For example, they may be molded separately and then assembled using screw fixing or welding. Also, in the second embodiment, similar to the first embodiment, press-fitting and crimping are used to fix the valve body 20' inside the outer tube 10, but are not limited to this. For example, press-fitting only, crimping only, screw fixing, welding, or adhesive fixing may be used. Furthermore, in the second embodiment, by making the inner circumferential surface of the second connecting portion 12B a valve stopper 40', the number of parts can be reduced compared to the first embodiment, and the assembly work can be simplified.

[0092] <About the valve body> The valve body 20' is made of a metal material such as brass and is formed by machining or other processes. The valve body 20' comprises a valve seat portion 21 and a valve holder portion 22'. Since the valve seat portion 21 has the same configuration as in the first embodiment, the valve holder portion 22' will be described here.

[0093] In the second embodiment, the shape of the valve port 21A is a circular cross-sectional shape, but it is not limited to this, and may be an elliptical cross-sectional shape, a polygonal cross-sectional shape, or the like.

[0094] The valve holder portion 22' is erected on the other end side of the outer circumference of the valve seat 21B and has a cylindrical side wall portion 22A' that defines the valve chamber VC (see Figure 9) on its inside. The axial length of this side wall portion 22A' in the direction of L is smaller than the axial length of the valve body 30B in the direction of L. In addition, the outer surface of the side wall portion 22A' abuts against the outer tube portion 10.

[0095] <About the valve body> As shown in Figures 7(b) to 7(d), the valve body 30B is made of a high-strength resin material such as polyetheretherketone (PEEK) and has an axis L30B parallel to the axis L direction. With this configuration, the valve body 30A can be made lighter while maintaining strength compared to metal materials. The valve body 30B comprises a valve body end face 31B having a flat disc shape, a valve body side face 32B (side face) which is a cylindrical outer curved surface, a frustoconical portion 36B which is continuous with the other end of the valve body side face 32B and has a frustoconical shape, and a plurality (for example, three) of leg portions 35B which are evenly arranged in the circumferential direction and extend from the valve body side face 32B and the frustoconical portion 36B to the other end.

[0096] The valve body end face 31B has a flat, annular sealing portion 31Ba on its radial outer periphery, and this sealing portion 31Ba abuts against the flat, annular valve seat 21B. Therefore, the outer diameter of the valve body end face 31B is set to be larger than the inner diameter of the valve seat 21B, that is, the inner diameter of the valve port 21A. In addition, the outer diameter of the valve body side surface 32B is set to be slightly smaller than the inner diameter of the inner circumferential surface 22Aa' of the side wall 22A', so that the valve body 30B can slide within the side wall portion 22A' in the axial direction L. Furthermore, the outer diameter of the virtual outer periphery of the leg portion 35B (see Figure 7(d)) ​​is set to be slightly smaller than the inner diameter of the valve body housing portion 13 of the outer tube portion 10, so that the valve body 30B can slide within the valve body housing portion 13 of the outer tube portion 10.

[0097] Furthermore, as shown in Figure 8(a), the valve body 30B has a tapered portion 33B between the valve body side surface 32B and the seal portion 31Ba, which tapers in diameter from the valve body side surface 32B to the seal portion 31Ba.

[0098] In the second embodiment, as shown in FIG. 7(c), the valve body 30B is provided with a cylindrical valve body side surface 32B and a frustum-shaped frustum portion 36B. However, the present invention is not limited to this. For example, it may be provided with a cylindrical valve body side surface and a hemispherical hemispherical portion. Further, in the second embodiment, the longitudinal cross-sectional shape of the tapered portion 33B is a linear shape. However, the present invention is not limited to this. For example, it may be a curved longitudinal cross-sectional shape that reduces the diameter from the valve body side surface 32B to the seal portion 31Ba.

[0099] <Operation of the check valve> The operation of the check valve 100B will be described with reference to FIGS. 7 and 9. Here, the connection state between the check valve 100B and the external device (see FIG. 5), the initial pressure state (P1 < P2), etc. are the same as those in the first embodiment.

[0100] First, as shown in FIG. 7, when the valve body 30B is seated on the valve seat 21B and the seal portion 31Ba is in contact with the valve seat 21B in the valve closed state, when the primary pressure P1 and the secondary pressure P2 (< P1) are respectively applied to one end side and the other end side of the valve body 30B, a differential pressure (P1 - P2) in the valve opening direction is generated in the valve body 30B.

[0101] When this differential pressure (P'1 - P2) in the valve opening direction exceeds a predetermined threshold value, as shown in FIG. 9, the valve body 30B separates from the valve seat 21B and enters the valve open state. In this valve open state, the fluid that has flowed into the valve chamber VC from the primary opening 11C through the valve port 21A passes through the radial clearance between the valve body side surface 32B and the inner peripheral surface of the outer pipe portion 10 and between the adjacent leg portions 35B, and after reuniting in the accommodation chamber HC of the outer pipe portion 10, it flows to the secondary opening 12C on the other end side in the direction of the axis L.

[0102] [[ID=I7]] In this valve open state, when the differential pressure (P1 - P2) in the valve opening direction applied to the valve body 30B is relatively large, as shown in FIG. 9, the valve body 30B continues to move to the other end side within the outer pipe portion 10 while slidingly contacting the inner peripheral surface of the outer pipe portion 10 with the leg portion 35B. However, finally, the other end surface of the leg portion 35B abuts against the valve stopper 40', which is the inner peripheral surface of the second connecting portion 12B, thereby restricting the movement to the other end side.

[0103] After that, when the primary pressure P1 becomes smaller than the secondary pressure P2 (P1 < P2) due to a pressure drop in the pressure supply source or the like, a differential pressure (P2 - P1) in the valve closing direction is generated on the valve body 30B, and the valve body 30B returns to the valve closed state of seating on the valve seat 21B, preventing backflow from the secondary opening 12C to the primary opening 11C.

[0104] <Regarding the valve body centering means (1) (introducing the primary pressure into the annular tapered portion space)> The valve body centering means (1) (introducing the primary pressure into the annular tapered portion space) in the second embodiment is the same as that in the first embodiment. Therefore, it will be briefly described here using FIG. 8. Note that the gaps shown in FIGS. 8(b) to (d) are exaggerated for better understanding. Also, in the state from the slightly open state to immediately before valve opening shown in FIGS. 8(b) to (c), since the fluid velocity is extremely slow, the static pressure is dominant over the dynamic pressure.

[0105] First, in the valve closed state shown in FIG. 8(a), an annular tapered portion space St that is continuous in the circumferential direction when viewed from the axial direction L is defined by the tapered portion 33B, the radially extended line of the seal portion 31Ba of the valve body 30B, and the side wall portion 22A'. Here, as shown in FIG. 7(a), the valve body 30B is eccentric with respect to the valve main body 20'. While the right side of the valve body side surface 32B contacts the inner peripheral surface of the side wall 22Aa', the left side of the valve body side surface 32B is separated from the inner peripheral surface of the side wall 22Aa'. At this time, the length of the side wall portion 22A' in the axial direction L is made smaller than the length of the valve body 30B in the axial direction L, and when viewed from the direction orthogonal to the axis L, the other end surface 22Ab' of the side wall is arranged at a position overlapping the valve body side surface 32B. Also, the outer peripheral edge of the leg portion 35B is in a non-contact state with the inner peripheral surface of the valve main body housing portion 13.

[0106] Next, as shown in Figures 8(b) and (c), from the slightly open state to the state just before valve opening, the valve body centripetal means (1) (introduction of primary side pressure into the annular tapered space) introduces the primary side pressure P1 into the annular tapered space St via the valve chamber VC. As a result, similar to the first embodiment, the sum of the radial pressing forces Ftr (see Figure 8(b)) that create a non-uniform pressure distribution along the circumferential direction becomes the centripetal force, acting on the valve body 30B so that the axis L30B of the valve body 30B becomes coaxial with the axis L of the valve body 20'. At this time, the radial gap between the leg portion 35B and the outer tube portion 10 is set to be larger than the gap between the valve body side surface 32B and the inner circumferential surface 22Aa' of the side wall. As a result, the valve body 30B moves in the valve opening direction while being radially centripetal, without contact with the side wall portion 22A' and the outer tube portion 10 (see M1' and M2' in Figures 8(b) and (c)).

[0107] Then, as shown in Figure 8(d), in the open valve state, a differential pressure (P1'-P2') (see Figure 9) is applied to the valve body 30B in the valve opening direction, and as the valve body 30B moves in the valve opening direction (see M3' in Figure 2(d)), the fluid that flows from the valve port 21A into the valve chamber VC flows into the containment chamber HC of the outer pipe section 10.

[0108] Thus, in the second embodiment, similar to the first embodiment, by employing a valve body centering means (1) (introduction of primary side pressure into the annular tapered space), the axis L30B of the valve body 30B becomes coaxial with the axis L of the valve body 20' between the slightly open state and the state just before valve opening. As a result, the valve body 30B can move in the valve opening direction without contacting the side wall portion 22A'. Therefore, regardless of whether the valve is vertically or horizontally positioned, even with a relatively small differential pressure in the valve opening direction, the conventional problem (decreased valve opening performance) can be resolved and reliability can be improved.

[0109] Furthermore, in the second embodiment, in order to omit the communication hole, the axial length of the side wall portion 22A' in the axial direction L is made smaller than the axial length of the valve body 30B in the axial direction L, and in the valve closed state, the other end face of the side wall 22Ab' is positioned to overlap with the valve body side surface 32B when viewed from a direction perpendicular to the axis L, thereby eliminating concerns (reduced responsiveness due to the effect of burrs).

[0110] Furthermore, in the second embodiment, as in the first embodiment, by further adopting at least one of the valve body centering means (2) (increase in radial pressing force), the valve body centering means (3) (large movement length in which the radial pressing force acts), and the valve body centering means (4) (weight reduction of the valve body), the axis L30B of the valve body 30B can be more reliably centered on the axis L of the valve body 20'.

[0111] <Regarding the valve body centering means (2) (increase in radial pressing force)> As shown in Fig. 8(a), the valve body centering means (2) (increase in radial pressing force) makes the axial length a' of the tapered portion 33B larger than the radial length b' of the tapered portion 33B (1 < a' / b'), that is, the angle θ' formed by the tapered portion 33B with respect to the axis L (see Fig. 8(a)) is less than 45° (θ < 45°). Thereby, as shown in Fig. 8(b), the centering force, which is the sum of the radial pressing forces Ftr acting on the valve body 30B, can be increased, so that the axis L30B of the valve body 30B can be more reliably centered on the axis L of the valve body 20' from the slightly open state to the state just before valve opening. In order to surely increase the radial pressing force Ftr, it is preferable that 5 ≤ a' / b'.

[0112] <Regarding the valve body centering means (3) (large movement length in which the radial pressing force acts)> The valve body centering means (3) (large movement length under radial pressure) is such that, as shown in Figure 8(a), the length c' over which the valve body 30B moves along the axis L from the closed state to the state just before the valve opens is at least half the length a' of the tapered portion 33B in the axis L direction (0.5 ≤ c' / a'). This allows the length over which the valve body 30A moves along the axis L from the slightly open state to the state just before the valve opens (see Figures 8(b) and 8(c)) to be increased, thereby more reliably centering the axis L30B of the valve body 30B towards the axis L of the valve body 20'. However, if the length over which the valve body 30A moves along the axis L under radial pressure Ftr is made too long, the time from the closed state to the open state will increase, which may lead to a decrease in responsiveness, so it is preferable to set it to 0.5 ≤ c' / a' ≤ 0.9.

[0113] <Regarding valve body centering means (4) (lightweighting of the valve body)> The valve body centering means (4) (lightweighting of the valve body) is provided in the valve body 30B as shown in Figure 7(c), by providing a weight-reducing hole 34B in the valve body 30B that is not penetrated, extending from the center of the other end face of the frustoconical portion 36B toward one end along the axis L30B of the valve body 30B. By making the valve body 30B lighter, even if a small centripetal force acts on the valve body 30B due to a relatively small differential pressure in the valve opening direction (P1'-P2') between the slightly open state and the state just before valve opening, the axis L30B of the valve body 30B can be more reliably centered toward the axis L of the valve body 20'.

[0114] Thus, in the second embodiment, in addition to valve body centering means (1) (introduction of primary side pressure into the annular tapered space), similar to the first embodiment, at least one of valve body centering means (2) (increase in radial pressing force), valve body centering means (3) (increase in the travel length over which the radial pressing force acts), and valve body centering means (4) (lightening of the valve body) is further employed, thereby enabling the axis L30B of the valve body 30B to be centered more reliably with the axis L of the valve body 20'.

[0115] (Valve body modification) Here, valve body modifications 1 and 2 in the second embodiment will be described using Figure 10. Valve body modifications 1 and 2 differ from the second embodiment in that the shape of one end face 31B', 31B'' of the valve body is not a flat surface, but the other basic configurations are the same as those of the second embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0116] <Regarding concerns (inhibition of smooth movement due to valve tilt during valve centering)> In the second embodiment, the valve body 30B, as in the first embodiment, has a flat surface at one end face 31B, which means it is susceptible to the effects of dynamic pressure. Specifically, when the fluid collides with the valve body end face 31B between the slightly open state and the state just before valve opening (see Figures 8(b) and (c)), three-dimensional turbulence is generated, resulting in a dynamic pressure distribution that is uneven when viewed from the direction of the axis L at one end face 31B. Therefore, there was a concern related to this dynamic pressure (suppression of smooth movement due to the tilt of the valve body when it is centered).

[0117] In contrast, in the modified valve body of the second embodiment, similar to the modified valve body of the first embodiment, the valve body centering means (5) (suppression of valve body tilting during valve body centering: recess) in modified valve body 1, or the valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) in modified valve body 2 can be further adopted to resolve the concern (suppression of smooth movement due to valve body tilting during valve body centering).

[0118] <Regarding valve body centering means (5) (Suppression of valve body tilting during valve body centering: recess)> Using Figure 10(a), the valve body centering means (5) (recess for suppressing valve body tilting during valve body centering) in the modified valve body 1 of the second embodiment will be explained. This valve body centering means (5) (recess for suppressing valve body tilting during valve body centering) has a mortar-shaped recess 31Bb' formed on one end face 31B' of the valve body, coaxial with the valve body 30B' and recessed in a mortar shape toward the other end, and the seal portion 31Ba' is formed between the mortar-shaped recess 31Bb' and the tapered portion 33B. As a result, at least while the centering action on the valve body 30B' is acting, the fluid in the mortar-shaped recess 31Bb' stagnates, and a static pressure with a uniform distribution is applied to the one end face 31B' of the valve body when viewed from the direction of the axis L, thus eliminating the concern (suppression of smooth movement due to valve body tilting during valve body centering).

[0119] In addition, the mortar-shaped recess 31Bb' of the modified valve body 1 is a cone shape with a circular base, but it is not limited to this, as long as it is recessed in a mortar shape, it may also be a polygonal pyramidal shape with a polygonal base, for example.

[0120] <Regarding valve body centering means (6) (Suppression of valve body tilting during valve body centering: recessed and convex parts)> Using Figure 10(b), the valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) in the modified valve body 2 of the second embodiment will be explained. This valve body centering means (6) (suppression of valve body tilting during valve body centering: recess and protrusion) has a V-shaped protrusion 31Bc'' that protrudes in a V-shape toward one end side coaxially with the valve body 30B'' on one end face 31B'' of the valve body, and an annular recess 31Bb'' that is recessed in an annular shape toward the other end side coaxially with the valve body 30B'' around the V-shaped protrusion 31Bc'', and the seal portion 31Ba' is formed between the annular recess 31Bb'' and the tapered portion 33B. As a result, at least while the centripetal force is acting on the valve body 30B'' (at least from the slightly open state to the state just before valve opening), the fluid flows smoothly radially outward due to the rectifying effect of the V-shaped protrusion 31Bc'' and then stagnates in the annular recess 31Bb''. Therefore, when viewed from the direction of the axis L, dynamic pressure is applied to the center of one end face 31B'' of the valve body as a uniform distribution in the circumferential direction, and static pressure is applied to the periphery, thus eliminating the concern (suppression of smooth movement due to the tilt of the valve body when it is centered).

[0121] In addition, the V-shaped protrusion 31Bc'' of the valve body modification 2 is a cone shape with a circular base, but it is not limited to this, as it only needs to protrude in a V-shape, so for example it may be a polygonal pyramidal shape with a polygonal base.

[0122] As described above, in the second embodiment and valve body modifications 1 and 2, similar to the first embodiment, by employing valve body centering means (1) (introduction of primary side pressure into the annular tapered space), it is possible to eliminate the conventional problem (decreased valve opening performance) and improve reliability, even with a relatively small differential pressure in the valve opening direction, regardless of whether the valve is vertically or horizontally positioned.

[0123] Furthermore, in the second embodiment and valve body modifications 1 and 2, the communication hole is omitted, thus eliminating concerns (reduced responsiveness due to the effect of burrs).

[0124] Furthermore, in the second embodiment and valve body modification 1 and 2, similar to the first embodiment, by further employing at least one of the valve body centering means (2) (increase in radial pressing force), valve body centering means (3) (increase in the travel length over which the radial pressing force acts), and valve body centering means (4) (lightening of the valve body), the axis L30B of the valve bodies 30B, 30B', and 30B'' can be more reliably centered on the axis L of the valve body 20'.

[0125] In addition, by further employing the valve body centering means (5) (recessed valve body tilting during valve body centering: recess) in valve body modification 1, or the valve body centering means (6) (recessed and convex portion) in valve body modification 2, the concerns (suppression of smooth movement due to valve body tilting during valve body centering) can be resolved, similar to valve body modification 1 or valve body modification 2 of the first embodiment.

[0126] <Other> It goes without saying that the check valves 100A and 100B of this embodiment are applicable to all fluid devices and fluid circuits, including refrigeration circuits. Furthermore, the present invention is not limited to the embodiments described above, and can be modified or altered as appropriate without departing from the technical spirit of the present invention. [Explanation of Symbols]

[0127] 100A, 100B check valve 10 Outer tube part 11 Primary joint section 11A Primary cylindrical section 11B First connection part 11C Primary opening 12 Secondary joint section 12A Secondary cylindrical section 12B Second connection part 12C Secondary opening 13 Valve body housing 13A First enlarged diameter section 13B Second enlarged diameter section 13C Step section 13D fixed part 20,20' Valve body 21 Valve seat 21A valve port 21B Valve seat 21C Aperture section 21D Flange section 22,22' Valve holder section 22A,22A' Side wall part 22Aa, 22Aa' Inner surface of the side wall (inner surface of the side wall portion) 22Ab' Other end face of the side wall (other end face of the side wall portion) 22B Communication hole 22Ba One end of communication hole 22Bb Other end of communication hole 22C Annular groove section 30A, 30A', 30A'', 30B, 30B', 30B'' Valve body 31A, 31A', 31A'', 31B, 31B', 31B'' Valve body end face (Valve body end face) 31Aa, 31Aa', 31Ba, 31Ba' seal section 31Ab', 31Bb' Mortar-shaped recess 31Ab'',31Bb'' Annular recess 31Ac'',31Bc'' Mountain-shaped protrusion 32A, 32B Valve body side view 33A, 33B Tapered section 34A, 34B Weight reduction holes 35B Legs 36B Truncated cone section 40,40' Valve stopper 200 Indoor heat exchanger 300 Outdoor heat exchanger 400 Expansion valve 500 square valve 600 Compressor 1000 Refrigeration Cycle System Ft pressing force Ftl Axial pressure Ftr Radial pressure Large radial gap area in the GL region GS radial gap small area HC containment chamber (secondary internal space) L axis L30A,L30B shaft center P intersection point P1, P1' primary-side pressure P2, P2' secondary-side pressure St annular tapered portion space VC valve chamber θ, θ' angle

Claims

1. An outer tube portion extending along the axial direction and having a cylindrical shape, The valve body housed in the outer tube portion, A valve body provided so as to be able to contact the valve body, A valve element centering means for centering the axis of the valve element on the axis of the valve body, It is equipped with a check valve, The valve body comprises a valve seat portion having a valve seat and a valve port, and a valve holder portion having a cylindrical side wall portion that defines a valve chamber and is erected from the outer circumference of the valve seat, The valve body comprises a valve body side surface that can contact the side wall, a sealing portion provided only on one end surface of the valve body, and a tapered portion that narrows in diameter from the valve body side surface to the sealing portion. The valve body is provided to be movable in the axial direction between a valve-closed state in which the sealing portion is in contact with the valve seat and a valve-open state in which the sealing portion is separated from the valve seat and the valve port and the secondary internal space of the outer tube portion are in communication. The valve body centering means is characterized in that, in a slightly open state in which the valve chamber and the valve port begin to communicate, primary pressure is introduced into the annular tapered space defined by the tapered portion, the radial extension of the seal portion, and the side wall portion, thereby enabling movement of the valve body in a direction perpendicular to the axis of the valve body.

2. The check valve according to claim 1, characterized in that the valve body centering means makes the axial length of the tapered portion larger than the radial length of the tapered portion.

3. The check valve according to claim 1, characterized in that the valve body centering means ensures that the length over which the valve body moves along the axial direction from the closed state to the state immediately before the valve opens is at least half the axial length of the tapered portion.

4. The check valve according to claim 1, characterized in that the valve body has a weight-reducing hole that extends in the axial direction of the valve body and does not penetrate through it.

5. A mortar-shaped recess is formed on one end face of the valve body, coaxially with the valve body and recessed in a mortar shape toward the other end. The check valve according to claim 1, characterized in that the sealing portion is formed between the mortar-shaped recess and the tapered portion.

6. On one end face of the valve body, a V-shaped projection is formed coaxially with the valve body and projecting toward the one end, and an annular recess is formed around the V-shaped projection coaxially with the valve body and recessing toward the other end. The check valve according to claim 1, characterized in that the sealing portion is formed between the annular recess and the tapered portion.

7. The axial length of the side wall portion is greater than the axial length of the valve body. The side wall portion is provided with a plurality of communication holes located at a distance from the valve seat, which connect the secondary internal space of the outer tube portion and the valve chamber in the radial direction. The check valve according to claim 1, characterized in that the plurality of communication holes are arranged opposite to the side surface of the valve body from the valve closed state to the state just before the valve opens.

8. The check valve according to claim 7, characterized in that, when the valve is open and the axis of the valve body and the axis of the valve body are coaxially arranged, all of the intersections between the inner surface of the side wall and the other end of the plurality of communication holes are located inside a virtual frustocone shape formed by virtually extending the tapered portion toward the other end, regardless of the axial position of the valve body.

9. The axial length of the side wall portion is smaller than the axial length of the valve body. The check valve according to claim 1, characterized in that, in the valve closed state, the other end face of the side wall portion is positioned to overlap with the side surface of the valve body when viewed from a direction perpendicular to the axis.

10. A refrigeration cycle system characterized by comprising a check valve as described in any one of claims 1 to 9.

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