non-return valve

Abstract

This ensures that the pressure equalization port functions reliably, resulting in a check valve with a good valve closing response. [Solution] A check valve comprising a cylindrical valve body 12 having an inlet 15 at one end and a bottom wall 14 at the other end, with an outlet 16 in the circumferential wall 13, and a valve element 18 housed within the valve body so as to be movable in the axial direction of the valve body and movable between a closed position in which it abuts against a valve seat 15a formed in the inlet to close the inlet, and an open position in which it is separated from the valve seat to open the inlet, wherein the circumferential wall or bottom wall is provided with a plurality of pressure equalization holes 17 arranged at positions spaced apart from each other in the circumferential direction, allowing fluid to flow from outside the valve body to the back side of the valve element when the valve is closed. Preferably, the check valve has three or more pressure equalization holes, and the pressure equalization holes are formed such that at least one pressure equalization hole is positioned higher than the central axis in any rotational state when the check valve is rotated 360° around the central axis of the valve body.

Description

Technical Field

[0001] The present invention relates to a check valve, and particularly to a valve structure for preventing a delay in the valve closing operation.

Background Art

[0002] Refrigeration and refrigeration devices and air-conditioning equipment using a refrigeration cycle are widely used today. For example, a heat pump type air-conditioning system capable of heating and cooling is used as an air conditioner for transportation machinery such as a car air conditioner, a room air conditioner for housing and stores, and a central air-conditioning facility for large buildings.

[0003] Also, in such an air-conditioning system, a check valve is used in a refrigerant pipe (for example, a branch part, etc.) to switch the flow path of the refrigerant.

[0004] FIG. 11 and FIG. 12 show an example of a conventional check valve (in a valve closed state). As shown in this figure, the check valve 41 has a cylindrical valve body 12, a valve element 18 slidably accommodated inside the valve body 12, and a coil spring 19 for biasing the valve element 18. The valve body 12 has an inlet 15 at one end, the other end is closed by a bottom wall 14, and the peripheral wall 13 has an outlet 16. A valve seat 15a with which the valve element 18 comes into contact and separates is formed at the inlet 15. The valve element 18 has a disk-shaped valve element main body portion 18a and a guide portion 18b for slidably supporting the valve element main body portion 18a in the axial direction, and is biased toward the valve seat 15a by the coil spring 19. The valve element main body portion 18a has a valve member 18c capable of closing the inlet 15 by contacting the valve seat 15a.

[0005] When the pressure of the fluid flowing in from the inlet 15 exceeds the biasing force of the coil spring 19, the valve body 18 moves axially (to the right in Figure 11) due to the fluid pressure, opening both the inlet 15 and the outlet 16, resulting in an open valve state (see Figure 13). In the open valve state, the fluid that flows into the valve body 12 from the inlet 15 flows out of the valve body 12 from the outlet 16, flowing to the right in Figure 13 (see arrow F). On the other hand, when the pressure of the fluid flowing in from the inlet 15 becomes less than the biasing force of the coil spring 19, the valve body 18 is pushed back by the biasing force of the coil spring 19 and moves to the left in Figure 13, and when the valve member 18c comes into contact with the valve seat 15a, the inlet 15 is closed, resulting in a closed valve state (see Figure 11).

[0006] Furthermore, the following patent document discloses a check valve used in such an air conditioning system. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2014-74436 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, during the valve closing operation, which transitions from the open state (Figure 13) to the closed state (Figure 11), the internal space 20 on the back side of the valve body 18 (the side opposite to the side facing the valve seat 15a), that is, the space enclosed by the back side of the valve body portion 18a, the inner circumferential surface of the guide portion 18b, the inner circumferential surface of the valve body 12, and the inner surface of the bottom wall 14 (in this application, including the present invention and embodiments described later, this space is referred to as the "valve internal space"), becomes negatively pressurized. This causes a problem in which the valve closing reaction is delayed (in other words, the operability or responsiveness of the valve closing operation is reduced).

[0009] Specifically, during the valve closing operation described above, fluid (refrigerant, etc.) is drawn into the valve space 20 from outside the valve body 12 through the gap between the inner surface of the peripheral wall 13 of the valve body 12 and the outer surface of the valve element 18. However, since the inner surface of the peripheral wall 13 and the outer surface of the valve element 18 are sliding surfaces where the valve element 18 and the valve body 12 slide against each other, the gap is narrow, making it difficult for fluid to pass through. In particular, if refrigerant oil seeps into the gap and forms an oil film, it becomes even more difficult for air to be drawn in, and the valve closing response deteriorates.

[0010] On the other hand, in order to resolve the above-mentioned problems, it is also conceivable to provide a pressure equalization hole 17 in the valve body 12, as shown in Figures 14 and 15, and to draw air into the valve internal space 20 through this pressure equalization hole 17 when the valve is closed.

[0011] However, as described above, simply providing the equalizing hole 17 may cause the equalizing hole 17 to become blocked by the refrigerant oil 30 when it accumulates in the valve space 20, as shown in Figures 16 and 17, rendering it inoperable.

[0012] Therefore, the objective of the present invention is to realize a check valve with a good valve closing response by ensuring that the pressure equalization hole functions more reliably. [Means for solving the problem]

[0013] [First Invention] To solve the aforementioned problems and achieve the objective, the check valve according to the first invention of the present application comprises a cylindrical valve body and a valve element. The valve body has an inlet at one end, the other end closed by a bottom wall, and an outlet on its circumferential wall. The valve element is housed inside the valve body so as to be movable in the axial direction of the valve body, and is movable between a closed valve position in which it abuts against a valve seat formed at the inlet and closes the inlet, and an open valve position in which it moves away from the valve seat and opens the inlet. Furthermore, the check valve is provided with a plurality of pressure equalization holes on the circumferential wall of the valve body, which are arranged at positions spaced apart from each other in the circumferential direction and allow fluid to flow from the outside of the valve body to the back side of the valve element when the valve is closed.

[0014] Furthermore, it is preferable that the above-mentioned multiple pressure equalization holes be formed between the outlet and the bottom wall, and in particular, in a position near the bottom wall (for example, closer to the bottom wall than the midpoint between the inlet and the bottom wall). This is to prevent the pressure equalization holes from being blocked by the valve body, which moves axially (towards the bottom wall) inside the valve body. Also, in this application, "fluid" refers to a gas such as a refrigerant gas, or a liquid such as a liquid refrigerant or refrigerant oil. In addition, the check valve according to the first invention may have a coil spring. The coil spring is provided between the bottom wall of the valve body and the valve body, and biases the valve body toward the closed position.

[0015] In the conventional check valves described above (Figures 11 to 13), the valve interior space on the back side of the valve body becomes negatively pressurized, hindering the movement of the valve body. In contrast, with the check valve according to the first invention, when the valve is closed, fluid flows from outside the valve body into the valve interior space through the pressure equalization holes, eliminating the negative pressure in the valve interior space and improving the operability during valve closing. Moreover, since it is equipped with multiple pressure equalization holes formed at positions spaced apart in the circumferential direction, it becomes less likely for the pressure equalization holes to be blocked by refrigerant oil accumulated in the valve interior space, as described above, thus reducing the possibility of delays in the valve closing reaction. The same effects and advantages apply to the second invention described below. In this application, the first and second inventions together are referred to as "the present invention."

[0016] [Second Invention] The check valve according to the second invention of this application comprises a valve body (a cylindrical valve body having an inlet at one end and being closed at the other end by a bottom wall, with an outlet on the circumferential wall) similar to the check valve according to the first invention, and a valve element (a valve element housed inside the valve body so as to be movable in the axial direction of the valve body, and movable between a closed valve position in which it abuts against a valve seat formed at the inlet to close the inlet, and an open valve position in which it is separated from the valve seat to open the inlet), and has a plurality of pressure equalization holes arranged at positions spaced apart from each other in the circumferential direction to allow fluid to flow from outside the valve body to the back side of the valve element when the valve is closed, but the pressure equalization holes are formed in the bottom wall.

[0017] In addition, in the second invention, the check valve may further include a coil spring. The coil spring is provided between the bottom wall of the valve body and the valve element, and biases the valve element toward the closed position. When the coil spring is provided in this way, it is preferable that the plurality of pressure equalizing holes are arranged outside the coil spring when viewed from the central axis direction of the valve body. This is to prevent a situation where all the pressure equalizing holes are blocked by the refrigerating machine oil accumulated in the valve inner space.

[0018] Furthermore, in order to more reliably reduce the possibility of a delay in the closing reaction, it is preferable for the check valves according to the first and second inventions to adopt the following structure.

[0019] The plurality of pressure equalizing holes include a first pressure equalizing hole, a second pressure equalizing hole, and a third pressure equalizing hole, and when the check valve is rotated 360° around the central axis of the valve body, at least one of the first pressure equalizing hole, the second pressure equalizing hole, and the third pressure equalizing hole is arranged at a position higher than the central axis of the valve body in any rotational state. Each pressure equalizing hole (the first pressure equalizing hole, the second pressure equalizing hole, and the third pressure equalizing hole) is formed in this way.

[0020] As a more specific example of the above structure, as follows, an example is given where adjacent pressure equalizing holes are arranged radially at equal intervals in the circumferential direction.

[0021] (1) When three pressure equalizing holes are provided, the adjacent pressure equalizing holes around the central axis of the valve body are arranged so as to form an angle of, for example, 120° with each other when viewed from the central axis direction.

[0022] (2) When four pressure equalizing holes are provided, the adjacent pressure equalizing holes around the central axis of the valve body are arranged so as to form an angle of, for example, 90° with each other when viewed from the central axis direction.

[0023] Note that when five or more pressure equalizing holes are provided, the same structure (arranged radially at equal intervals) can be adopted.

Advantages of the Invention

[0024] According to the present invention, a check valve with a good closing reaction can be realized by making the pressure equalizing holes function more reliably.

[0025] Other objects, features, and advantages of the present invention will be clarified by the following description of the embodiments of the present invention described based on the drawings. In each figure, the same reference numerals indicate the same or corresponding parts.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is a longitudinal sectional view showing the closed state of the check valve according to the first embodiment of the present invention (an enlarged view of part E in FIG. 7). [Figure 2] FIG. 2 is a longitudinal sectional view showing the open state of the check valve according to the first embodiment (an enlarged view of part E in FIG. 7). [Figure 3] FIG. 3 is a cross-sectional view showing the check valve according to the first embodiment (section B-B in FIG. 2 / the flow path block is not shown). [Figure 4] FIG. 4 is a front view showing the flow path block in which the check valve according to the first embodiment is installed. [Figure 5] FIG. 5 is a left side view showing the flow path block in which the check valve according to the first embodiment is installed. [Figure 6] FIG. 6 is a right side view showing the flow path block in which the check valve according to the first embodiment is installed. [Figure 7] FIG. 7 is a longitudinal sectional view showing the flow path block in which the check valve according to the first embodiment is installed (section C-C in FIG. 5). [Figure 8] FIG. 8 is a cross-sectional view showing the flow path block in which the check valve according to the first embodiment is installed (section D-D in FIG. 7). [Figure 9] FIG. 9 is a longitudinal sectional view showing the open state of the check valve according to the second embodiment of the present invention in the same manner as FIG. 3. [Figure 10] FIG. 10 is a cross-sectional view showing the check valve according to the second embodiment (section B1-B1 in FIG. 9 / the flow path block is not shown). [Figure 11]Figure 11 is a longitudinal cross-sectional view showing an example of a conventional check valve (closed state), similar to Figure 1. [Figure 12] Figure 12 is a cross-sectional view (section B2-B2 in Figure 11) showing the conventional check valve. [Figure 13] Figure 13 is a longitudinal cross-sectional view showing the open state of the conventional check valve. [Figure 14] Figure 14 is a longitudinal cross-sectional view showing a comparative example in which a check valve is provided with a pressure equalization hole. [Figure 15] Figure 15 is a cross-sectional view (section B3-B3 in Figure 14) showing a comparative example in which a check valve is provided with a pressure equalization hole. [Figure 16] Figure 16 is a longitudinal cross-sectional view, similar to Figure 14, showing the state in which refrigerant oil has accumulated in the valve space of the check valve according to the comparative example. [Figure 17] Figure 17 is a cross-sectional view (section B4-B4 in Figure 16) showing the state in which refrigerant oil has accumulated in the valve space of the check valve according to the comparative example, similar to Figure 15. [Modes for carrying out the invention]

[0027] [First Embodiment] A check valve according to the first embodiment of the present invention will be described with reference to Figures 1 to 8.

[0028] As shown in Figures 1 to 8, the check valve 11 according to the first embodiment of the present invention is installed and used within a flow path block 22 having an inlet passage 23 and an outlet passage 24, and has the function of allowing fluid to pass from the inlet passage 23 to the outlet passage 24, while blocking fluid to pass from the outlet passage 24 to the inlet passage 23.

[0029] The flow path block 22 consists of a block body 25 having a check valve housing hole (hereinafter sometimes simply referred to as "housing hole") 27 for housing the check valve 11, and a cover 26 fixed to the right side of the block body 25 so as to close the check valve housing hole 27. The inflow passage 23 extends horizontally from the left side of the block body 25 to the right. The housing hole 27 extends horizontally from the right side of the block body 25 to the left and communicates with the inflow passage 23.

[0030] The cover 26 has a cover body portion 26a fixed to the right side of the block body 25, and a base portion 26b that protrudes to the left from the left side of the cover body portion 26a and is inserted into the housing hole 27. The outflow passage 24 passes horizontally through the center of the cover body portion 26a.

[0031] The base portion 26b has a thick-walled cylindrical shape, and its central hole 26c communicates with the outflow passage 24. In addition, the peripheral wall of the base portion 26b has four notched grooves 26d formed in a cross shape when viewed from the axial direction (in this application, the direction of the horizontally extending central axis A is referred to as the "axial direction"). These notched grooves 26d allow fluid that flows out from the outlet 16 (described later) of the check valve 11 into the housing hole 27 and flows into the outflow passage 24.

[0032] Furthermore, the base portion 26b abuts against the bottom wall 14 (described later) of the valve body 12 of the check valve 11, pressing the check valve 11 against the left end of the housing hole 27 and thereby fixing the check valve 11 inside the housing hole 27. In this fixed state, a fluid flow path (referred to as the "flow path space" in this application and indicated by reference numeral 21) is formed between the outer circumferential surface of the valve body 12 and the inner circumferential surface of the housing hole 27. As will be described later, when the valve is open, the fluid that flows out from the outlet 16 of the check valve 11 flows through the flow path space 21 to the outflow passage 24.

[0033] The fixing structure for the check valve 11 into the housing hole 27 is not particularly limited. For example, various structures can be used, such as press-fitting the left end of the valve body 12 (the end on the inlet passage 23 side) into the housing hole 27, screwing it in (forming a female thread on the inner circumferential surface of the housing hole 27 and forming a male thread on the outer circumferential surface of the valve body 12 that screws into the female thread), or fixing it with adhesive or crimping.

[0034] The check valve 11 installed in the housing hole 27 has a cylindrical valve body 12, a valve element 18, and a coil spring 19. The valve body 12 has an inlet 15 at one end that communicates with the inlet passage 23, and the other end is closed by a bottom wall 14. In addition, an outlet 16 is formed in the peripheral wall 13 of the valve body 12 that communicates with the outlet passage 24 via a flow path space 21 and a central hole 26c of the base portion 26b. The inlet 15 has a ring-shaped valve seat 15a that the valve element 18 (valve member 18c described later) moves toward and away from (contacts and separates from) it.

[0035] The valve body 18 has a disc-shaped valve body portion 18a and a cylindrical guide portion 18b that supports the valve body portion 18a so as to be slidable in the axial direction. The valve body portion 18a is equipped with a ring-shaped valve member 18c that can close the inlet 15 by contacting the valve seat 15a. A coil spring 19 is installed between the valve body portion 18a and the bottom wall 14 in a compressed state, thereby biasing the valve body 18 (valve body portion 18a) toward the valve seat 15a. In this embodiment, the biasing force of the coil spring 19 in its installed state is set to a small value, for example, so that even if the valve body 18 moves away from the valve seat 15a due to a change in the posture of the check valve 11 or the like when the differential pressure between the inlet passage 23 and the outlet passage 24 is small, a biasing force is applied that is sufficient to keep the valve body 18 in contact with the valve seat 15a and maintain a closed state.

[0036] In this embodiment, four outlets 16 are provided that penetrate the peripheral wall 13 of the valve body 12. These outlets 16 are arranged radially when viewed from the axial direction, and adjacent outlets 16 are arranged circumferentially at an angle of 90° to each other.

[0037] Furthermore, in this embodiment, the bottom wall 14 is provided with a plurality (three in this embodiment) of pressure equalization holes (intake holes) 17. These pressure equalization holes 17 are positioned spaced apart from each other in the circumferential direction. That is, in this embodiment, when viewed from the axial direction, adjacent pressure equalization holes 17 are arranged radially and at an angle of 120° to each other in the circumferential direction. The reason for this arrangement is to ensure that no matter what position the check valve 11 is in (i.e., no matter how it is rotated around the central axis A), at least one pressure equalization hole 17 is positioned higher (upper) than the central axis A. This prevents (or reduces the possibility of) a situation occurring where all the pressure equalization holes 17 become blocked and the valve becomes inoperable even if refrigerant oil accumulates in the valve internal space 20.

[0038] Furthermore, the pressure equalization hole 17 is positioned in the vicinity (proximity) of the bottom wall 14 in the axial direction. This is to prevent the pressure equalization hole 17 from being blocked by the valve body 18, which moves axially (towards the bottom wall 14) inside the valve body 12. Moreover, in this embodiment, the following structure is adopted so that the pressure equalization hole 17 is not blocked even in the fully open state shown in Figure 2, that is, when the valve body 18 (guide portion 18b) is in contact with the bottom wall 14 of the valve body 12.

[0039] A ring-shaped outer groove 18d (see Figure 1) extending in the circumferential direction is formed on the outer circumferential surface of the right end of the guide portion 18b. This outer groove 18d extends around the entire circumference of the guide portion 18b, and at the right end of the guide portion 18b where the outer groove 18d is formed, a gap (ring-shaped space) is formed between the guide portion 18b of the valve body 18 and the circumferential wall 13 of the valve body 12. Furthermore, multiple notched grooves 18e (for example, three) are provided by cutting the right end of the guide portion 18b over a certain width in the circumferential direction (see Figure 3). These notched grooves 18e are formed so as to face the pressure equalization hole 17 (so that when viewed from the axial direction, they are arranged radially and adjacent notched grooves 18e are arranged at a 120° angle to each other in the circumferential direction).

[0040] Furthermore, the notched groove 18e extends radially so as to penetrate the guide portion 18b, connecting the inside and outside of the guide portion 18b, and also communicating with the outer peripheral groove 18d. Therefore, in this embodiment, even when fully open (see Figure 2), the outside of the valve body 12 (flow path space 21) and the inside of the guide portion 18b (valve internal space 20) are in communication via the equalizing hole 17, the outer peripheral groove 18d, and the notched groove 18e, allowing fluid to flow between the flow path space 21 and the valve internal space 20.

[0041] The operation of the check valve 11 according to this embodiment is as follows:

[0042] When the pressure on the outlet passage 24 side (outlet passage 24 and the flow path space 21 communicating with it) is higher than the pressure on the inlet passage 23 side (inlet passage 23 and the inlet 15 communicating with it), as shown in Figure 1, the valve body portion 18a of the valve body 11 comes into contact with the valve seat 15a, closing the inlet 15 (closed valve state) and interrupting the flow of fluid.

[0043] On the other hand, when the pressure on the inlet passage 23 side (the side of the inlet passage 23 and the inlet 15 communicating with it) becomes higher than the pressure on the outlet passage 24 side (the side of the outlet passage 24 and the flow path space 21 communicating with it), and the differential pressure exceeds the biasing force of the coil spring 19, as shown in Figure 3, the valve body 18 moves along the inner surface of the valve body 12 toward the bottom wall 14, causing the valve body portion 18a to separate from the valve seat 15a and the inlet 15 to open. As a result, the fluid flows out from the inlet passage 23 through the inlet 15, outlet 16, flow path space 21, and the central hole 26c of the base portion 26b through the outlet passage 24 (see arrow F in Figure 3 / valve open state).

[0044] Furthermore, from this open valve state (Figure 3), conversely to the above, when the pressure on the outlet side becomes higher than the pressure on the inlet side (more precisely, when the difference between the pressure on the inlet side and the pressure on the outlet side (differential pressure) becomes smaller than the biasing force of the coil spring 19), the valve body 18 moves along the inner surface of the valve body 12 toward the valve seat 15a, and the valve member 18c comes into contact with the valve seat 15a, thereby closing the inlet 15 (the closed valve state in Figure 1). In the conventional check valve 41 (Figures 11 to 13), the valve internal space 20 becomes negative pressure during this closing operation, which sometimes hinders the movement of the valve body 18 toward the valve seat 15a. However, in the check valve 11 of this embodiment, during the closing operation, fluid flows from the flow path space 21 to the valve internal space 20 through the pressure equalization hole 17, and pressure balance is achieved between the valve internal space 20 and the flow path space 21, so the valve body 18 moves quickly toward the valve seat 15a. Thus, according to this embodiment, the operability when the valve is closed can be improved. Moreover, since at least one of the multiple pressure equalization holes 17 formed at circumferentially spaced positions is positioned higher than the central axis A, the above function (improved operability when the valve is closed) can be achieved regardless of the orientation (rotational state) of the check valve.

[0045] [Second Embodiment] A check valve 31 according to a second embodiment of the present invention will be described with reference to Figures 9 and 10. In this description, components identical or equivalent to those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted, with the focus being on the differences.

[0046] The check valve 31 according to the second embodiment of the present invention, like the check valve 11 according to the first embodiment, has a valve body 12, a valve element 18, a coil spring 19, and a plurality (three in this embodiment) of pressure equalization holes 17, and is used by being installed in a flow path block 22, but unlike the first embodiment, the pressure equalization holes 17 are formed in the bottom wall 14.

[0047] Furthermore, in order to prevent a situation in which all of the pressure equalization holes 17 are blocked by refrigerant oil 30 or the like accumulated in the valve space 20, all of the pressure equalization holes 17 are positioned outside the coil spring 19 (farther from the central axis A) when viewed from the axial direction, and adjacent pressure equalization holes 17 in the circumferential direction with respect to the central axis A of the valve body 12 are positioned at an angle of, for example, 120° to each other when viewed from the direction of the central axis A. This makes it possible, as in the first embodiment, that no matter what rotational state the check valve 31 is in (how much it has rotated around the central axis A), at least one of the three pressure equalization holes 17 is positioned higher than the central axis A.

[0048] Furthermore, in this embodiment, the three pressure equalization holes 17 are positioned so that they are not blocked by the base portion 26b when the check valve 31 is installed in the flow path block 22, and also so that they are not blocked by the ring-shaped bottom surface of the guide portion 18b when the valve body 18 is in a fully open state with the guide portion 18b in contact with the bottom wall 14 of the valve body 12 (see Figure 9). Specifically, the pressure equalization holes 17 should be positioned inside the central hole of the base portion (closer to the central axis A) and inside the inner circumferential surface of the guide portion 18b (closer to the central axis A).

[0049] The operation of the check valve 31 is the same as that of the check valve 11 in the first embodiment.

[0050] Although embodiments of the present invention have been described above, it will be apparent to those skilled in the art that the present invention is not limited to these embodiments and that various modifications can be made within the scope of the claims.

[0051] For example, the check valve 11 described in the first embodiment and the check valve 31 described in the second embodiment may each be configured without a coil spring 19, as an alternative example.

[0052] Furthermore, the check valve 11 of the first embodiment and the check valve 13 of the second embodiment may, as an alternative example, have the function of a so-called regulating valve, which applies a predetermined biasing force to the coil spring 19 and opens when the pressure on the inlet passage 23 side exceeds the predetermined pressure. In this case, the biasing force of the coil spring 19 in its installed state is determined according to the desired opening pressure. [Explanation of Symbols]

[0053] A center axis F Refrigerant flow 11,31,41 Check valve 12 Valve body 13 Peripheral wall 14 Bottom wall 14a Outer perimeter groove 14b Notched groove 15 Inlet 15a Valve seat 16 Outlet 17 Pressure equalization hole 18 Valve body 18a Valve body 18b Guide section 18c Valve member 18d Outer perimeter groove 18e Notched groove 19. Coil spring 20 Valve space 21 Flow channel space 22 Flow channel block 23 Inflow channel 24 Outflow channel 25 Block Body 26 Lid 26a Lid body 26b Base 26c Center hole of the base 26d cut groove 27 Check valve housing hole 30 Refrigeration oil

Claims

1. A cylindrical valve body having an inlet at one end, closed at the other end by a bottom wall, and having an outlet on its circumferential wall, A valve body is housed inside the valve body so as to be movable in the axial direction of the valve body, and is movable between a closed valve position in which it abuts against a valve seat formed in the inlet and closes the inlet, and an open valve position in which it is separated from the valve seat and opens the inlet. A check valve having, The circumferential wall is provided with a plurality of pressure equalization holes, which are arranged at positions spaced apart from each other in the circumferential direction and allow fluid to flow from the outside of the valve body to the back side of the valve element when the valve is closed. A check valve characterized by the following features.

2. The plurality of pressure equalization holes are formed between the outlet and the bottom wall. The check valve according to claim 1.

3. A coil spring is provided between the bottom wall and the valve body to bias the valve body toward the closed position. The check valve according to claim 1.

4. A cylindrical valve body having an inlet at one end, closed at the other end by a bottom wall, and having an outlet on its circumferential wall, A valve body is housed inside the valve body so as to be movable in the axial direction of the valve body, and is movable between a closed valve position in which it abuts against a valve seat formed in the inlet and closes the inlet, and an open valve position in which it is separated from the valve seat and opens the inlet. A check valve having, The bottom wall is provided with a plurality of pressure equalization holes, which are positioned spaced apart from each other in the circumferential direction and allow fluid to flow from the outside of the valve body to the back side of the valve element when the valve is closed. A check valve characterized by the following features.

5. A coil spring is provided between the bottom wall and the valve body to bias the valve body toward the closed position. The aforementioned plurality of pressure equalization holes are formed outside the coil spring when viewed from the central axis direction of the valve body. The check valve according to claim 4.

6. The plurality of pressure equalization holes include a first pressure equalization hole, a second pressure equalization hole, and a third pressure equalization hole. The first, second, and third pressure equalization holes are formed such that when the check valve is rotated 360° around the central axis of the valve body, at least one of the first, second, and third pressure equalization holes is positioned higher than the central axis in any rotational state. A check valve according to any one of claims 1 to 5.

Images