Check valve

Abstract

The present invention relates to a check valve. The check valve comprises a housing, an elastic member and a spherical valve core, wherein the housing defines a valve cavity around a central axis, the valve cavity comprising a first end and a second end which are opposite each other in an axial direction; the valve core and the elastic member are mounted in the valve cavity, and the elastic member axially pushes the valve core towards a first opening at the first end; the diameter of the valve cavity at the first end is greater than that thereof at the second end; the housing comprises one or more protrusions protruding from a side surface towards a radial inner side, or one or more recesses recessed towards a radial outer side; and the axial movement range of the valve core is limited between a first position and a second position: in the first position, the valve core closes the first opening; and in the second position, the valve core is away from the first opening and a second opening at the second end, and abuts against the protrusions or abuts against the side surface between the recesses, such that a fluid can flow across the valve core between the protrusions or in the recesses. The check valve of the present invention has an improved structure.

Description

Check valve Technical Field

[0001] This invention relates to the field of fluid control technology. Specifically, this invention relates to a check valve. Background Technology

[0002] A check valve, also known as a one-way valve, is an important component in fluid control systems. It primarily controls the flow of fluid in only one direction along a specific flow path. In various applications, the check valve is generally stationary relative to its mounting component. To open the check valve and allow fluid flow, the hydraulic pressure difference between the spaces on either side of the check valve must reach a predetermined minimum value in a predetermined direction—the opening pressure. The opening pressure of a check valve varies depending on its structure and dimensions. When the hydraulic pressure difference reaches the opening pressure, the check valve opens, allowing fluid to flow from the inlet to the outlet. When the hydraulic pressure difference drops below the opening pressure, the valve core experiences a reset pressure, at which point the check valve closes, preventing fluid from flowing back from the outlet to the inlet. In existing technologies, check valves can employ various closing mechanisms to achieve this one-way flow function; for example, springs or gravity can be used to close the valve core.

[0003] However, in some applications, check valves need to be installed within rotating components. When the check valve's spool is installed radially relative to the axis of rotation of the rotating component, the check valve may be subject to additional centrifugal force, which varies with the rotational speed of the component. If the centrifugal force acts on the spool precisely in the opening direction, then at excessively high speeds, the resulting centrifugal force may exceed the closing force from the closing mechanism, preventing the check valve from closing properly and thus causing the one-way flow function to fail. Furthermore, since centrifugal force is a parameter that varies with rotational state, while the spring's restoring force is based on predetermined parameters of spring stiffness, simply changing the spring parameters cannot prevent this centrifugal force-induced failure. Summary of the Invention

[0004] Therefore, the technical problem that this invention needs to solve is to provide an improved check valve.

[0005] The aforementioned technical problem is solved by a check valve according to the present invention. The check valve includes a housing, an elastic element, and a spherical valve core. The housing defines a valve cavity formed around a central axis. The valve cavity includes a first end and a second end opposed axially. The valve cavity is configured to introduce fluid through a first opening communicating to the first end. The valve core and the elastic element are mounted in the valve cavity. The elastic element pushes the valve core axially toward the first opening, allowing the valve core to open or close the first opening based on fluid pressure. The valve cavity is configured to discharge fluid through a second opening communicating to the second end. The housing defines a side surface of the valve cavity as a conical side surface extending obliquely relative to the central axis between the first and second ends, such that the diameter of the valve cavity at the first end is larger than the diameter at the second end. The housing includes one or more protrusions projecting radially inward from the side surface or one or more recesses recessed radially outward, the protrusions or recesses being circumferentially distributed at predetermined axial positions between the first and second ends. The axial movement range of the valve core is limited between a first position and a second position: in the first position, the valve core is located at the first end and closes the first opening; in the second position, the valve core is away from the first and second openings and abuts against the one or more protrusions or against the side surface in the circumferential region between the one or more recesses, allowing fluid to flow across the valve core between the one or more protrusions or in the one or more recesses, thereby connecting the first and second openings. By providing axially opposite inflow and outflow openings, the effective hydraulic diameter acting on the valve core is increased, and the fluid passing through the gap between the valve core and the side surface can generate a larger liquid pressure difference, thus allowing the valve core to be subjected to greater liquid pressure. Furthermore, due to the tapered structure of the side surface, the liquid pressure difference on both sides of the valve core in the axial direction increases as the valve core moves towards the tapered tip. The greater the centrifugal force on the valve core, the closer the valve core is to the tapered tip when it accidentally opens, and therefore the greater the liquid pressure required to close it again. This means that this check valve can provide a closing force adapted to changes in rotational speed and centrifugal force.

[0006] According to a preferred embodiment of the present invention, when the valve core is in the second position, in a cross-section passing through the central axis, the angle between the tangential direction of the contact point between the valve core and the housing and the central axis is a support tilt angle, which can be greater than 45 degrees. A larger support tilt angle can prevent the valve core from getting stuck in the second position and failing to reset.

[0007] According to another preferred embodiment of the present invention, in a cross-section passing through the central axis, the angle between the side surface and the central axis is the side inclination angle. The effective hydraulic diameter of the valve core is obtained by multiplying the diameter of the valve core by the cosine of the side inclination angle. The first opening has an opening diameter, and the effective hydraulic diameter can be larger than the opening diameter. This allows a larger effective hydraulic area to be formed on the valve core.

[0008] According to another preferred embodiment of the invention, when the valve core is in the second position, a flow gap normal to the side surface is formed between the valve core and the side surface or each recess. The total area of ​​the flow gap can be smaller than the cross-sectional area of ​​the first opening and / or the second opening. A smaller flow gap helps to generate a significant liquid pressure difference on both sides of the flow gap, thereby generating a greater restoring force.

[0009] According to another preferred embodiment of the invention, each protrusion may have an arcuate profile in a cross-section passing through the central axis. This reduces stress concentration on the contact surface and ensures smooth contact between the valve core and the protrusion.

[0010] According to another preferred embodiment of the invention, the housing may include a flange surrounding the radially outer side of the second opening, the flange projecting axially toward the first end, and the end of the elastic member facing the second end surrounding the radially outer side of the flange. This achieves the limiting of the elastic member.

[0011] According to another preferred embodiment of the invention, the one or more protrusions may consist of at least three protrusions spaced apart circumferentially, or the one or more recesses may consist of at least three recesses spaced apart circumferentially. This forms a stable support for the valve core. In this case, each protrusion or each recess may have the same shape and size; and / or, the at least three protrusions or the at least three recesses may be uniformly distributed circumferentially. This ensures that the supporting force on the valve core is evenly distributed.

[0012] According to another preferred embodiment of the invention, the housing may include a cylindrical valve cover defining one of a first end and a second end of a valve cavity, as well as a side surface, and forming a corresponding one of a first opening and a second opening, wherein a valve core and an elastic element may be mounted radially inside the valve cover. The valve cover thereby provides the volume of the valve cavity.

[0013] According to another preferred embodiment of the invention, the housing may further include a valve seat, to which the valve cover is fixed, the valve seat defining the other of a first end and a second end, and forming the other of a first opening and a corresponding second opening. Thus, the open end of the valve cover can be closed by the valve seat, and the valve core and resilient element can be easily disassembled and assembled by separating the valve seat and the valve cover. Attached Figure Description

[0014] The invention is further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0015] Figure 1 shows a longitudinal sectional view of a check valve according to an exemplary embodiment of the present invention;

[0016] Figure 2 shows a simplified structural schematic diagram of a check valve according to an exemplary embodiment of the present invention; and

[0017] Figure 3 shows a comparison diagram of a prior art check valve and a check valve according to an exemplary embodiment of the present invention. Detailed Implementation

[0018] The following describes specific embodiments of the check valve according to the present invention with reference to the accompanying drawings. The detailed description and drawings below are provided to illustrate the principles of the invention, and the invention is not limited to the described preferred embodiments; the scope of protection of the invention is defined by the claims.

[0019] According to an embodiment of the present invention, a check valve is provided. This check valve can be applied to various fluid control systems to achieve unidirectional fluid flow. This check valve is particularly suitable for fluid control systems in rotating components.

[0020] Figure 1 illustrates an exemplary embodiment of the check valve according to the present invention. As shown in the longitudinal sectional view of Figure 1, the check valve mainly includes a housing, a valve core 30, and an elastic element 40. The housing defines a valve cavity C for accommodating the valve core 30 and the elastic element 40. The valve cavity C is a generally truncated conical cavity formed around a central axis O. The valve cavity C includes a first end and a second end opposite each other along the axial direction. As shown in Figure 1, the lower end is the first end, which serves as the inlet end of the valve cavity C and communicates with an inflow path. An opening (preferably substantially axial) of the inflow path connecting to the first end is called a first opening 11, through which fluid can be introduced into the valve cavity C from the first end. The upper end is the second end, which serves as the outlet end of the valve cavity C and communicates with an outflow path. An opening (preferably substantially axial) of the outflow path connecting to the second end is called a second opening 21, through which fluid can be discharged from the valve cavity C from the second end. Therefore, the fluid flows through the check valve generally along the axial direction.

[0021] Both the valve core 30 and the elastic element 40 are mounted in the valve cavity C. As shown in Figure 1, the valve core 30 is formed as a generally spherical component. The elastic element 40 can be a component made of various elastic materials, capable of generating an elastic force acting on the valve core 30 generally axially through elastic deformation. For example, the elastic element 40 can be a helical spring, whose central axis is generally parallel to, and preferably generally coincides with, the central axis O of the valve cavity C. The force exerted by the elastic element 40 on the valve core 30 is generally axially directed towards the first end, particularly pushing the valve core 30 towards the first opening 11, causing the valve core 30 to tend to close the first opening 11 towards the first end. Specifically, the elastic element 40 can be in a pre-compressed state, axially abutting against a portion of the housing (e.g., the end wall of the second end) and the valve core 30, and is located axially on the side of the valve core 30 facing the second end. At the same time, the valve core 30 is also subjected to the liquid pressure in the valve cavity C, the direction of which may point towards the first end or the second end based on the liquid pressure difference between the upper and lower sides. The valve core 30 can open or close the first opening 11 based on the liquid pressure. Generally, if the liquid pressure in the inflow path connected to the first opening 11 is greater, a liquid pressure pointing towards the second end can be generated. When this liquid pressure is greater than the elastic force of the elastic element 40, the valve core 30 moves away from the first end and towards the second end, thereby opening the first opening 11. At this time, fluid can flow from the first opening 11 into the valve chamber C and out through the second opening 21. Conversely, if the liquid pressure in the inflow path connected to the first opening 11 does not exceed the liquid pressure in the outflow path connected to the second opening 21, no liquid pressure pointing towards the second end can be generated. The valve core 30 abuts against the first end under the action of the elastic force and closes the first opening 11, thereby prohibiting the flow through the valve chamber C.

[0022] As shown in Figure 1, the truncated conical valve cavity C has a generally conical side surface. This side surface is a closed surface without any channel openings. This side surface extends obliquely relative to the central axis O between the first and second ends of the valve cavity C. The diameter of the side surface narrows axially from the first end to the second end, such that the diameter of the valve cavity C at the first end is larger than the diameter at the second end.

[0023] Under the influence of elastic force and fluid pressure, the valve core 30 can move approximately axially within the valve cavity C. The axial movement range of the valve core 30 within the valve cavity C is limited at the lower end of Figure 1 by the end wall of the first end—as shown by the solid line in Figure 1—this extreme position is called the first position. In the first position, the valve core 30 is located at the first end and closes the first opening 11. The extreme position of the axial movement of the valve core 30 toward the second end is limited by the conical side surface or additional structures on the side surface—as shown by the dashed line in Figure 1—this extreme position is called the second position. In the second position, the valve core 30 is both away from the first opening 11 at the first end and has not reached the second opening 21 at the second end, causing both openings to open simultaneously, thereby allowing fluid to flow axially through the check valve via both openings. The axial movement range (i.e., the stroke range S) of the valve core 30 is thus limited between the first and second positions.

[0024] In the embodiment shown in Figure 1, the housing includes one or more protrusions 22 that project radially inward from the side surface, located at a predetermined axial position (height position along the central axis O) between the first and second ends, thereby axially spaced from the axial ends of the valve cavity C. When multiple such protrusions 22 are present, they are circumferentially spaced at the same predetermined axial position, i.e., having the same axial height but different circumferential positions. In the second position, the valve core 30 abuts against each protrusion 22, preventing further movement of the valve core 30 toward the second end. Each protrusion 22 can be formed as a generally point-like, columnar, conical, hemispherical, or similar shape, i.e., its circumferential dimension is significantly smaller than the circumference of the side surface at its location, and its axial dimension is also significantly smaller than the axial dimension of the side surface. Due to the presence of the protrusions 22, the valve core 30 in the second position cannot form a region that contacts the side surface along a complete circumference; therefore, fluid can flow across the valve core 30 through the gap between the valve core 30 and the side surface. When there is one or two protrusions 22, the valve core 30 in the second position not only abuts against the protrusions 22, but also needs to directly abut against the side surface in some local positions to achieve a stable state, forming gaps between the protrusions 22 and the local contact positions in the circumferential direction and (in the case of two protrusions 22) between adjacent protrusions 22 in the circumferential direction; when there are three or more protrusions 22, by reasonably distributing these protrusions 22 in the circumferential direction (preferably evenly distributed), the valve core 30 in the second position can be stably supported on these protrusions 22 without directly contacting the side surface, thus forming gaps between adjacent protrusions 22 in the circumferential direction and between the side surface and the valve core 30 in the radial direction.

[0025] Alternatively, the housing may include one or more recesses, rather than protrusions 22, that are recessed radially outward from the side surface. Similar to protrusions 22, the recesses are also located at a predetermined axial position between the first and second ends and are axially spaced from the axial ends of the valve cavity C. When multiple such recesses are present, they are also circumferentially spaced at the same predetermined axial position. In this case, in the second position, the valve core 30 abuts against the side surface in the region between the recesses circumferentially, that is, directly abuts against the side surface region where no recess is formed at the axial position where the recess is located, while fluid can flow across the valve core 30 through the recesses. In this case, the recesses are preferably formed as elongated grooves with a significant circumferential extension, such that the side surface region between adjacent recesses has a relatively short circumferential length, particularly a circumferential length close to the axial width of the recess. Similar to protrusions 22, when the number of recesses is three or more, it can be ensured that the valve core 30 in the second position is stably supported on the side surface without contacting the recesses.

[0026] When the valve core 30 opens the first opening 11, the fluid flowing between the first opening 11 and the second opening 21 needs to pass through a cross-section with the smallest flow area in a certain region of the axial middle of the valve core 30. Due to energy loss caused by the fluid compression and expansion process, this results in a difference in liquid pressure on the upper and lower sides of the valve core 30. If the check valve accidentally opens due to centrifugal force when the pressure at the outflow end is greater than the pressure at the inflow end, the fluid will tend to flow from the second opening 21 toward the first opening 11. At this time, due to this middle region with a reduced flow area, the fluid will generate a larger liquid pressure difference on the valve core 30 toward the first opening 11. At the same time, as shown in Figure 2, the effective cross-section of the liquid pressure difference at this time is the cross-section corresponding to the point of tangency of the valve core 30 with respect to the parallel line of the valve cavity C side surface (i.e., the cross-section passing through the point of tangency and perpendicular to the central axis O). Compared with the prior art where the fluid flows in from one end of the valve cavity and flows out from the side, the check valve of this invention has a larger liquid pressure difference and an effective cross-section, thereby generating greater liquid pressure to promote the valve core 30 to overcome centrifugal force and close the check valve. On the other hand, the axial position of the valve core 30 that is accidentally opened due to centrifugal force is positively correlated with the centrifugal force (and / or rotational speed); that is, the greater the centrifugal force, the closer the valve core 30 is to the second position. At this point, due to the conical structure of the valve cavity C, the closer the valve core 30 is to the second position, the smaller the gap between the valve core 30 and the side surface, the smaller the effective flow area at the point of reduced flow area, and the greater the closing pressure difference generated on the valve core 30. This means that the centrifugal force, the degree of opening of the check valve, and the restoring force that causes the valve core 30 to close are all positively correlated. This check valve thus provides a restoring force that can vary based on the centrifugal force (and / or rotational speed) to prevent the valve core 30 from accidentally opening.

[0027] In check valves according to various embodiments, the housing defining the valve cavity C may consist of one or more components. For example, as shown in FIG1, in an exemplary embodiment, the housing may include a valve seat 10 and a valve cover 20, which are formed independently of each other and assembled together. The valve cover 20 defines a second end and side surface of the valve cavity C (i.e., provides a side wall and an end wall of the first end of the valve cavity C), and a second opening 21 communicating to the second end is also formed in the valve cover 20 accordingly. The valve cover 20 thereby provides the volume of the valve cavity C. A valve core 30 and an elastic element 40 are mounted radially inside the valve cover 20. This valve cover 20 may be formed as a generally cylindrical or cup-shaped component. The other end of the valve cover 20 (opposite to the second end) is formed as an open end for mounting the valve core 30 and the elastic element 40. The valve cover 20 is fixedly mounted to the valve seat 10. The valve seat 10 closes the open end of the valve cover 20, thereby defining a first end of the valve cavity C (i.e., providing an end wall of the first end). A first opening 11 connecting to the first end is also formed in the valve seat 10. For example, as shown in FIG1, the valve seat 10 may be formed with a recess, and the valve cover 20 may be fixed to the recess by an interference fit.

[0028] It should be noted that the split-type housing embodiment is mainly for ease of processing and assembly. Those skilled in the art can recombine and redesign the specific structure of the housing as needed. For example, the end wall of the first end can be combined with the side surface to form the valve cover 20, while the valve seat 10 provides the end wall of the second end. Furthermore, the housing of the check valve as a product may not provide end wall structures to close the first and / or second ends, but only a conical structure defining the valve cavity C, i.e., the valve seat 10 may not be included. The corresponding end walls can be provided by the existing structure in the flow path where the check valve is applied.

[0029] Figure 2 shows some structural parameters of the check valve according to an exemplary embodiment. As shown in Figure 2, in a cross-section through the central axis O, the angle between the side surface of the valve cavity C and the central axis O can be called the side inclination angle θ1, which is half the cone apex angle of the side surface. The diameter of the effective action section of the liquid pressure difference on the valve core 30 can be called the effective hydraulic diameter D. According to the foregoing analysis and geometric calculation, the effective hydraulic diameter D is equal to the diameter of the valve core 30 multiplied by the cosine (cosθ1) of the side inclination angle θ1. The diameter of the cross-section of the first opening 11 perpendicular to the central axis O can be called the opening diameter D'. Preferably, the effective hydraulic diameter D can be greater than the opening diameter D'. The left side of Figure 3 shows the effective hydraulic diameter in the prior art, while the right side shows the effective hydraulic diameter according to the present invention. As shown on the left side of Figure 3, if the fluid inlet (first opening 11) is located at the bottom and the fluid outlet is located on the side, the effective hydraulic diameter is the opening diameter D' of the first opening 11; while in the present invention, by adjusting the side inclination angle θ1, the effective hydraulic diameter D can be greater than the opening diameter D. This increases the area of ​​the effective action section.

[0030] As shown in Figure 2, when there are three or more protrusions 22 or recesses, viewed in a cross-section through the central axis O, the angle between the tangential direction of the contact point between the valve core 30 and the housing (the contact point on the protrusion 22 or the contact point on the side surface between the recesses) and the central axis O when the valve core 30 is in the second position can be called the support tilt angle θ2. The support tilt angle θ2 affects the degree to which the valve core 30 in the second position is clamped between the protrusions 22 or on the side surface. Preferably, the support tilt angle θ2 can be designed to be greater than 45 degrees, and particularly preferably about 60 degrees, thereby preventing the valve core 30 from jamming in the second position.

[0031] As shown in Figure 2, when the valve core 30 is in the second position, a flow gap G, normal to the side surface, is formed between the valve core 30 and the side surface or each recess. This gap is the minimum distance relative to the valve core 30 measured along the normal direction of the side surface. The flow gap G is typically a conical cross-sectional area. In some cases, this area may also be divided into multiple circumferentially distributed gap areas by the protrusion 22. Whether it is a complete conical flow gap G or a separated discrete flow gap G, the total area of ​​the flow gap G is preferably smaller than the cross-sectional area of ​​the first opening 11 and / or the second opening 21. Here, the cross-sectional area of ​​the first opening 11 and the second opening 21 refers to the opening area perpendicular to the central axis O. This structure ensures that the area of ​​the flow gap G is smaller, thereby enabling a larger liquid pressure difference to be generated on the upper and lower sides of the valve core 30 with the flow gap G as the boundary.

[0032] For the housing of the check valve, particularly the portion of the housing that provides the valve cavity side surface, such as the valve cover 20 in the embodiment shown in FIG. 1, it can preferably be formed as a thin-walled structure, for example, a cylindrical housing formed by stamping a metal sheet. This means that the protrusion 22 or recess on the inner surface of the valve cavity C will be formed as a corresponding reverse complementary structure on the corresponding outer surface, i.e., a recess corresponding to the protrusion 22 or a protrusion corresponding to the recess. To facilitate the stamping process, it is preferable to form the protrusion 22 inside the valve cavity C.

[0033] In a preferred embodiment, when the protrusion 22 is formed in the valve cavity C, each protrusion 22 preferably has an arcuate profile when viewed in a cross section passing through the central axis O, thereby ensuring that the protrusion 22 can smoothly contact the valve core 30 and avoid stress concentration.

[0034] As previously mentioned, by providing at least three protrusions 22 or at least three recesses spaced circumferentially, stable support for the valve core 30 in the second position can be ensured. Furthermore, to ensure force balance and support stability, each protrusion 22 or each recess preferably has the same shape and size. Additionally, these protrusions 22 or these recesses are also preferably evenly distributed circumferentially.

[0035] When the valve core 30 is in the second position, its radial position is defined by the protrusion 22 or by the side surface area between the recesses. When the valve core 30 is in the first position, its radial position is defined by the first opening 11. To allow the valve core 30 to move substantially along the central axis O, in both the first and / or second positions, the valve core 30 is preferably radially confined to be coaxial with the central axis O. For this purpose, and also to tightly close the first opening 11, the first opening 11 preferably has a circular cross-section, the diameter of which should be smaller than the diameter of the valve core 30.

[0036] As shown in Figure 1, in a preferred embodiment, the housing may include a flange surrounding the radially outer side of the second opening 21. This flange projects axially toward the first end, and the end of the elastic element 40 facing the second end surrounds the radially outer side of the flange and abuts against the end wall of the second end. For example, in the embodiment shown in Figure 1, this flange is formed inside the top tip of the valve cover 20. By providing the flange, the radial position of the elastic element 40, in the form of a helical spring, can be effectively defined.

[0037] The check valve according to the present invention significantly increases the effective liquid pressure difference and effective working cross-section acting on the valve core by arranging the inlet and outlet ports of the valve chamber axially opposite each other, thereby improving the hydraulic closing force against centrifugal force. Simultaneously, this check valve uses a conical valve chamber to correlate the valve core position with the effective liquid pressure difference, which establishes a positive correlation between the hydraulic closing force and centrifugal force or rotational speed through the valve core position, thus achieving a good effect in preventing accidental opening. Therefore, this check valve can operate normally over a wider range of rotational speeds.

[0038] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0039] Appendix Label Table

[0040] 10 Valve seat

[0041] 11 First Opening

[0042] 20 Valve cover

[0043] 21 Second opening

[0044] 22. Protrusion

[0045] 30 Valve Core

[0046] 40 Elastic element

[0047] C Valve cavity

[0048] D Effective hydraulic diameter

[0049] D' Opening diameter

[0050] G Flow gap

[0051] O Central axis

[0052] S travel range

[0053] θ1 Lateral tilt angle

[0054] θ2 Support tilt angle

Claims

1. A check valve comprising a housing, an elastic element (40), and a spherical valve core (30), the housing defining a valve cavity (C) formed about a central axis (O), the valve cavity (C) including a first end and a second end axially opposed to each other, the valve cavity (C) configured to introduce fluid through a first opening (11) communicating with the first end, the valve core (30) and the elastic element (40) being mounted in the valve cavity (C), the elastic element (40) pushing the valve core (30) axially toward the first opening (11) such that the valve core (30) can open or close the first opening (11) based on fluid pressure, characterized in that, The valve chamber (C) is configured to discharge fluid through a second opening (21) communicating with the second end. The housing defines the side surface of the valve chamber (C) as a conical side surface extending obliquely relative to the central axis (O) between the first end and the second end, such that the diameter of the valve chamber (C) at the first end is greater than the diameter at the second end. The housing includes one or more protrusions (22) projecting radially inward from the side surface or one or more recesses recessing radially outward. The one or more protrusions (22) or the one or more recesses are circumferentially distributed at predetermined axial positions between the first end and the second end. The axial movement range of the valve core (30) is limited between a first position and a second position. In the first position, the valve core (30) is located at the first end and closes the first opening (11); In the second position, the valve core (30) is away from the first opening (11) and the second opening (21) and abuts against the one or more protrusions (22) or against the side surface in the region between the one or more recesses in the circumference, such that fluid can flow across the valve core (30) between the one or more protrusions (22) in the circumference or in the one or more recesses to connect the first opening (11) and the second opening (21).

2. The check valve according to claim 1, characterized in that, When the valve core (30) is in the second position, in a cross section passing through the central axis (O), the angle between the tangential direction of the contact point between the valve core (30) and the housing and the central axis (O) is the support tilt angle (θ2), which is greater than 45 degrees.

3. The check valve according to claim 1, characterized in that, In a cross section passing through the central axis (O), the angle between the side surface and the central axis (O) is the side tilt angle (θ1), and the effective hydraulic diameter (D) of the valve core (30) is obtained by multiplying the diameter of the valve core (30) by the cosine of the side tilt angle (θ1). The first opening (11) has an opening diameter (D'), and the effective hydraulic diameter (D) is greater than the opening diameter (D').

4. The check valve according to claim 1, characterized in that, When the valve core (30) is in the second position, a flow gap (G) normal to the side surface is formed between the valve core (30) and the side surface or each recess, and the total area of ​​the flow gap (G) is smaller than the cross-sectional area of ​​the first opening (11) and / or the second opening (21).

5. The check valve according to claim 1, characterized in that, In a cross section passing through the central axis (O), each protrusion (22) has an arcuate profile.

6. The check valve according to claim 1, characterized in that, The housing includes a flange that surrounds the radially outer side of the second opening (21), the flange projecting axially toward the first end, and the end of the elastic member (40) facing the second end surrounding the radially outer side of the flange.

7. The check valve according to any one of claims 1 to 6, characterized in that, The one or more protrusions (22) are composed of at least three protrusions (22) spaced apart in the circumferential direction, or the one or more depressions are composed of at least three depressions spaced apart in the circumferential direction.

8. The check valve according to claim 7, characterized in that, Each protrusion (22) or each recess has the same shape and size; and / or, the at least three protrusions (22) or the at least three recesses are evenly distributed circumferentially.

9. The check valve according to claim 8, characterized in that, The housing includes a cylindrical valve cover (20) that defines one of the first and second ends of the valve cavity (C) and the side surface, and is formed with a corresponding one of the first opening (11) and the second opening (21), wherein the valve core (30) and the elastic element (40) are mounted radially inside the valve cover (20).

10. The check valve according to claim 9, characterized in that, The housing also includes a valve seat (10), to which the valve cover (20) is fixed, the valve seat (10) defining one of the first end and the second end, and forming the other of the first opening (11) and the second opening (21).

Images