overflow valve

Abstract

The application provides a kind of overflow valve, including valve body, valve piston and valve elastic element, the valve body is opened with the valve cavity including the piston cavity and elastic element cavity being communicated, the piston includes piston rod and piston head, the end surface of the piston rod away from the piston head is piston tail surface, the valve elastic element is pressed in elastic element cavity and one end abuts on piston head, the circumferential outer contour of the piston rod is same with the circumferential inner contour of the piston cavity, the valve body has through hole that is communicated to the piston cavity, the valve body has seat surface at the junction of piston cavity and elastic element cavity, when the piston tail surface is not under external liquid pressure, the piston rod is arranged in the piston cavity, the piston head is in the elastic element cavity and abuts on seat surface, characterized in that, the valve cavity further includes damping cavity at the other end of piston cavity and communicated with piston cavity, the damping cavity has opening with less cross-sectional area along the direction perpendicular to the axis of overflow valve.

Description

Technical Field

[0001] This application relates to an overflow valve, and more particularly to an overflow valve that can reduce damage. Background Technology

[0002] In the hydraulic circuit of a fuel engine, the fuel pump needs to supply a certain margin of fuel to ensure that the downstream demand can be fully met. Excess fuel needs to be released, and this is typically achieved by installing a relief valve in the hydraulic passage.

[0003] Please see Figure 1 As shown, the overflow valve 90 includes a valve body 91, a valve piston 92, a valve spring 93, and a valve ball 94. The valve body 91 has a communicating cylindrical piston chamber 912 and spring chamber 913, with the diameter of the spring chamber 913 being larger than the diameter of the piston chamber 912. The valve piston 92 includes a head 921 and a body 922, the head 921 being larger than the body 922. The body 922 reciprocates within the piston chamber 912 and the spring chamber 913, and its dimensions are the same as those of the piston chamber 912. The head 921 is disposed within the spring chamber 913.

[0004] During operation, when the liquid pressure on the valve piston 92 exceeds the elastic force of the valve spring 93, the valve piston 92 moves to the right. When the bottom surface of the valve piston 92 passes the drain hole 915 on the valve body 91, which communicates with the piston chamber 912, some high-pressure fuel is released from the drain hole 915, and the liquid pressure on the valve piston 92 decreases rapidly. The valve piston 92 then moves to the left, and its head 921 sits on the seat surface 932 at the connection between the piston chamber 912 and the spring chamber 913. The rapid sitting of the head 921 causes an impact, which may damage the valve spring 93, the valve body 91, or the valve piston 92. Summary of the Invention

[0005] The purpose of this application is to solve the problem of easy damage in the overflow valve in the prior art.

[0006] To achieve the aforementioned objectives, a relief valve is provided, comprising a valve body, a valve piston, and a valve elastic element. The valve body has a valve cavity comprising a communicating piston cavity and an elastic element cavity. The piston includes a piston rod and a piston head. The end face of the piston rod away from the piston head is the piston tail face. One end of the valve elastic element, under pressure within the elastic element cavity, abuts against the piston head. The circumferential outer contour of the piston rod is the same as the circumferential inner contour of the piston cavity. The valve body has a through hole extending into the piston cavity. The valve body has a seat surface at the connection between the piston cavity and the elastic element cavity. When the piston tail face is not subjected to external liquid pressure, the piston rod is positioned within the piston cavity, and the piston head is located within the elastic element cavity and abuts against the seat surface. The valve cavity further comprises a damping cavity located at the other end of the piston cavity and communicating with it. The damping cavity has an opening having a cross-sectional area smaller than that of the piston cavity along a direction perpendicular to the axis of the relief valve.

[0007] This application also has the following feature: when the piston tail face is not subjected to liquid pressure, the damping chamber is located outside the piston tail face away from the piston head.

[0008] This application also has the following features: the outline of the damping cavity is a frustum structure with a cross-section that increases in the direction of the piston tail face along the direction perpendicular to the central axis of the overflow valve, or it is a hole with a cross-sectional area smaller than that of the piston cavity along the direction perpendicular to the axis of the overflow valve, or it is a stepped hole with a larger cross-sectional area in the direction closer to the piston tail face.

[0009] This application also has the following feature: the overflow valve has a valve plug at the end of the valve elastic element away from the piston rod.

[0010] This application also has the following feature: there is a liquid collecting cavity with the same circumferential inner contour as the piston cavity between the damping cavity and the piston cavity.

[0011] This application also has the following features: the piston cavity, the elastic element cavity and the liquid collection cavity all have a cylindrical inner contour.

[0012] This application also has the following feature: the valve elastic element is a valve spring.

[0013] This application also has the following feature: the valve body has a through hole extending into the cavity of the elastic element.

[0014] This application also has the following feature: the piston rod has a central hole extending from the piston tail towards the piston head, and the central hole does not penetrate to the piston head.

[0015] This application also has the following features: the piston rod has a fine hole that communicates with and penetrates the central hole, and when the piston tail face is not under liquid pressure, the fine hole is not in communication with the elastic element cavity.

[0016] Using the technical solution provided in this application, the overflow valve is less likely to be damaged. Attached Figure Description

[0017] Exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments described below are for illustrative purposes only and do not limit the scope of this application. In the accompanying drawings:

[0018] Figure 1 This is a planar sectional view of an overflow valve in the prior art;

[0019] Figure 2 This is a planar sectional view of an embodiment of the relief valve of this application, in which some components are removed to show the structure of the valve chamber.

[0020] Figure 3 This is a planar sectional view of an embodiment of the relief valve of this application, used to show the overall internal structure of the relief valve.

[0021] List of reference numerals in the attached diagram:

[0022] Valve body 10

[0023] Valve chamber 11

[0024] Piston chamber 12

[0025] Elastic cavity 13

[0026] Damping cavity 14

[0027] Through hole 15

[0028] Liquid collection chamber 16

[0029] Seat 17

[0030] Valve piston 20

[0031] Piston rod 21

[0032] Piston head 22

[0033] Central hole 23

[0034] 24 fine pores

[0035] Piston tail face 25

[0036] Valve elastic element 30

[0037] Valve plug 40 Detailed Implementation

[0038] It should be understood that the accompanying drawings are for illustrative purposes only, and the dimensions, scale relationships, and number of components are not intended to limit the scope of this application.

[0039] Please see Figure 2 and Figure 3 As shown, an embodiment of the overflow valve of this application includes a valve body 10, a valve piston 20, a valve elastic element 30, and a valve plug 40. The valve body 10 has a valve cavity 11 comprising a communicating piston cavity 12 and an elastic element cavity 13. The piston 20 includes a piston rod 21 and a piston head 22, with the end face of the piston rod 21 away from the piston head 22 being the piston tail face 25. The valve elastic element 30 is elastically pre-compressed within the elastic element cavity 13, with one end abutting against the piston head 22 and the other end connected to the valve plug 40. The valve plug 40 can be omitted in other embodiments, in which case the valve elastic element 30 needs to be fixed to other parts of the valve body 10.

[0040] In some embodiments, including this one, both the piston cavity 12 and the elastic element cavity 13 are cylindrical structures, with the radius of the elastic element cavity 13 being larger than the radius of the piston cavity 12. The circumferential outer contour of the piston rod 21 is the same as the circumferential inner contour of the piston cavity 12. The piston rod 21 has a central hole 23 extending from the piston tail face 25 towards the piston head 22, but this central hole 23 does not extend to the piston head 22. The piston rod 21 also has a fine hole 24 that communicates with and penetrates the central hole 23. When the piston tail face 25 is not under liquid pressure, the fine hole 24 is not connected to the elastic element cavity 13. When the piston rod 21 moves a certain distance towards the elastic element cavity 13, the fine hole 24 connects to the elastic element cavity 13.

[0041] The valve body 10 has a through hole 15 extending into the piston chamber 12. Additionally, the valve body 10 has a seat surface 17 at the connection between the piston chamber 12 and the elastic element chamber 13. When the piston tail face 25 is not under external liquid pressure, the piston rod 21 is positioned within the piston chamber 12, and the piston head 22 is located within the elastic element chamber 13 and abuts against the seat surface 17. The valve chamber 11 also includes a damping chamber 14 located at the other end of the piston chamber 12 and communicating with it. The damping chamber 14 has a frustum-shaped structure with an increasing cross-section perpendicular to the central axis of the relief valve, oriented towards the piston tail face 25. Between the damping chamber 14 and the piston chamber 12 is a liquid collecting chamber 16 with the same circumferential inner contour as the piston chamber 12.

[0042] In this embodiment, the valve elastic element 30 is a valve spring, one end of which abuts against the valve plug 40 and the other end of which abuts against the piston head 22. The valve spring is in a compressed state when installed in the relief valve.

[0043] Although not shown in the figure, in some embodiments including this one, the valve body 10 has a through hole (not shown) extending to the elastic element cavity 13.

[0044] When the piston tail face 25 is not under liquid pressure, or when the liquid pressure it experiences is less than the elastic force of the valve spring, the piston head 22 sits on the seat surface 17, and the piston rod 21 is located in the piston chamber 12. When the liquid in the collecting chamber 16 fills and the pressure begins to increase, until the liquid pressure on the piston tail face 25 exceeds the elastic force of the valve spring, the valve piston 20 is further compressed along the valve chamber 11 towards the valve plug 40, and the piston head 22 moves further towards the valve plug 40. When the aforementioned fine hole 24 moves into the elastic element chamber 13, the central hole 23 connects with the connecting hole through the fine hole 24, and the liquid pressure is partially released, thus making the valve spring run smoothly. When the liquid pressure further increases, the piston rod 21 continues to move towards the valve plug 40 until the piston tail face 25 connects with the through hole 15, and the liquid pressure is rapidly released, and the liquid in the collecting chamber 16 is quickly discharged, thus making the pressure on the piston tail face 25 less than the elastic force of the valve spring. At this time, the piston rod 21 moves away from the valve plug. After the piston tail face 25 ends its communication with the through hole 15, the piston rod 21 continues to move away from the valve plug. The liquid in the liquid collection chamber 16 is discharged through the damping chamber 14. The damping chamber 14 has an opening with a cross-sectional area smaller than that of the piston chamber 12 along the direction perpendicular to the axis of the overflow valve. In this embodiment, the inner contour of the damping chamber 14 is a frustum structure with a cross-section that increases in the direction of the piston tail face 25 along the direction perpendicular to the central axis of the overflow valve. Therefore, the liquid cannot be discharged quickly in the damping chamber 14, thereby reducing the speed of the piston rod 22 and making the piston head 22 sit on the seat surface 17 at a slower speed. This can reduce damage to the valve elastic element, seat surface, and piston head in the overflow valve.

[0045] It is understood that the structure of the damping cavity 14 can be other structures in other embodiments. For example, the damping cavity 14 can be a hole with a cross-sectional area smaller than that of the piston cavity along the direction perpendicular to the overflow valve axis. It can also be a stepped hole with a larger area facing the piston tail face 25.

[0046] It is understood that although in this embodiment the piston cavity, elastic element cavity, piston rod, and liquid collection cavity are all cylindrical structures, in other embodiments they may be all or partly of other structures.

[0047] In summary, the damping cavity in this application provides a buffer when the valve piston quickly sits down under the action of the valve spring, thus protecting the components of the relief valve and reducing damage.

Claims

1. An overflow valve comprising a valve body (10), a valve piston (20) and a valve spring (30), the valve body (10) having a valve chamber (11) with a piston chamber (12) and a spring chamber (13) in communication, the piston (20) comprising a piston rod (21) and a piston head (22), the end of the piston rod (21) away from the piston head (22) being a piston tail surface (25), the valve spring (30) being in compression in the spring chamber (13) and abutting the piston head (22) at one end, the circumferential outer contour of the piston rod (21) being identical to the circumferential inner contour of the piston chamber (12), the valve body (10) having a through hole (15) through to the piston chamber (12), the valve body (10) having a seat surface (17) at the connection of the piston chamber (12) and the spring chamber (13), the piston rod (21) being arranged in the piston chamber (12) and the piston head (22) being in the spring chamber (13) and abutting the seat surface (17) when the piston tail surface (25) is not under the pressure of a liquid, characterized in that The valve cavity (11) further comprises a damping cavity (14) at the other end of the piston cavity (12) and communicating with the piston cavity (12), the damping cavity (14) having an opening with a cross-sectional area smaller than that of the piston cavity (12) along a direction perpendicular to the axis of the overflow valve, the piston cavity (12) and the elastic member cavity (13) are both cylindrical in structure, and the radius of the elastic member cavity (13) is greater than that of the piston cavity (12).

2. The relief valve of claim 1, wherein When the piston tail surface (25) is not subjected to liquid pressure, the damping cavity (14) is outside the piston tail surface (25) away from the piston head (22).

3. The relief valve of claim 1, wherein The profile of the damping cavity (14) is a circular truncated cone structure with the cross-sectional area increasing along a direction towards the piston tail surface (25) and perpendicular to the central axis of the overflow valve, or a hole with a cross-sectional area smaller than that of the piston cavity along a direction perpendicular to the axis of the overflow valve, or a stepped hole with a larger cross-sectional area near the piston tail surface (25).

4. The relief valve of claim 1, wherein The overflow valve has a valve plug (40) at the end of the valve elastic member away from the piston rod (21).

5. The relief valve of claim 1, wherein The damping cavity (14) and the piston cavity (12) have a circumferential inner profile identical to that of the piston cavity (12).

6. The relief valve of claim 5, wherein The damping cavity (14) and the piston cavity (12) have a circumferential inner profile identical to that of the piston cavity (12).

7. The relief valve of any one of claims 1 or 6, wherein, The valve elastic member is a valve spring.

8. The relief valve of claim 7, wherein The valve body (10) has a communication hole penetrating to the elastic member cavity (13).

9. The overflow valve of claim 1 or 8, wherein The piston rod (21) has a central hole (23) extending from the piston tail surface (25) to the piston head (22), and the central hole (23) does not penetrate to the piston head (22).

10. The spill valve of claim 1 or 8, wherein The piston rod (21) has a fine hole (24) communicating with the central hole (23) and penetrating the piston rod (21), and when the piston tail surface (25) is not subjected to liquid pressure, the fine hole (24) does not communicate with the elastic member cavity (13).

Images