CN112392788A

CN112392788A - Overflow valve

Info

Publication number: CN112392788A
Application number: CN201910752428.4A
Authority: CN
Inventors: 魏巍
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-08-15
Filing date: 2019-08-15
Publication date: 2021-02-23

Abstract

The present application provides an overflow valve, which includes a valve body, a valve piston and a valve elastic member. The valve body is provided with a valve cavity including a connected piston cavity and an elastic member cavity. The piston includes a piston rod and a piston head. The end surface of the piston rod away from the piston head is the piston tail surface, one end of the valve elastic member under pressure in the elastic member cavity is abutted against the piston head, and the circumferential outer contour of the piston rod is in line with the piston cavity. The inner contour in the circumferential direction is the same, the valve body has a through hole that penetrates into the piston cavity, and the valve body has a seat surface at the connection between the piston cavity and the elastic member cavity. When the piston tail surface is not subject to external liquid pressure When the piston rod is arranged in the piston cavity, the piston head is located in the elastic member cavity and abuts with the seat surface. The damping chamber communicates with the chamber, and the damping chamber has an opening smaller than the cross-sectional area of the piston chamber along a direction perpendicular to the axis of the relief valve.

Description

Overflow valve

Technical Field

The present application relates to an overflow valve, and more particularly, to an overflow valve capable of reducing damage.

Background

In the hydraulic circuit of a fuel engine, the fuel pump provides fuel that requires some margin to ensure that the rear end needs can be fully met. The excess fuel needs to be released, and in order to release the fuel with certain pressure, a relief valve is usually arranged in the hydraulic channel.

Referring to fig. 1, the relief 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 cylindrical piston chamber 912 and a spring chamber 913 communicating with each other, and the diameter of the spring chamber 913 is larger than that of the piston chamber 912. The valve piston 92 includes a head 921 and a body 922, the head 921 being of a larger size than the body 922, the body 922 reciprocating within a piston chamber 912 and a spring chamber 913 of the same size as the piston chamber 912, the head 921 being disposed within the spring chamber 913.

In operation, when the valve piston 92 is subjected to a hydraulic pressure greater than the elastic force of the valve spring 93, the valve piston 92 moves rightward. When the bottom surface of the valve piston 92 passes through the drain hole 915 formed in the valve body 91 and communicating with the piston chamber 912, part of the high-pressure fuel is discharged from the drain hole 915, and the hydraulic pressure applied to the valve piston 92 is rapidly reduced. The valve piston 92 moves to the left, and the head 921 thereof is seated on the seat surface 932 at the junction of the piston chamber 912 and the spring chamber 913, and the rapidly seated head 921 causes an impact, which damages the valve spring 93 or the valve body 91 or the valve piston 92.

Disclosure of Invention

The application aims to solve the problem that in the prior art, an overflow valve is easy to damage.

In order to accomplish the above object, an overflow valve is provided, which comprises a valve body, a valve piston and a valve elastic member, wherein the valve body is provided with a valve cavity comprising a piston cavity and an elastic member cavity which are communicated with each other, the piston comprises a piston rod and a piston head, the end surface of the piston rod far away from the piston head is a piston tail surface, one end of the valve elastic member is pressed in the elastic member cavity and abutted 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 is provided with a through hole penetrating through the piston cavity, the valve body is provided with a seat surface at the joint of the piston cavity and the elastic member cavity, when the piston tail surface is not subjected to external liquid pressure, the piston rod is arranged in the piston cavity, the piston head is arranged in the elastic member cavity and abutted against the seat surface, and the valve cavity is characterized in that the valve cavity further comprises, the damping chamber is opened at a position smaller than the sectional area of the piston chamber in the direction perpendicular to the axis of the relief valve.

The present application also features the damping chamber being external to the piston tail face away from the piston head when the piston tail face is not subjected to fluid pressure.

The damping cavity is of a circular truncated cone structure with the profile increasing towards the tail face of the piston along the cross section perpendicular to the central axis of the overflow valve, or is a hole with the sectional area smaller than that of the piston cavity along the direction perpendicular to the axial direction of the overflow valve, or is a step hole with the sectional area larger in the direction close to the tail face of the piston.

The present application also features the relief valve having a valve plug at an end of the valve elastic member remote from the piston rod.

The present application also features a liquid collection chamber between the damping chamber and the piston chamber having a circumferential inner contour identical to the piston chamber.

The present application also features the piston chamber, spring chamber, and the sump chamber all having a cylindrical inner contour.

The present application also features the valve elastic member being a valve spring.

The present application also has a feature that the valve body has a communication hole penetrating to the elastic member chamber.

The present application also features the piston rod having a central bore extending from the piston tail face in a direction toward the piston head, the central bore not extending through to the piston head.

This application still has following characteristic, have on the piston rod with the centre bore intercommunication and run through the pore of piston rod when the piston tail face does not receive liquid pressure, pore and elastic component chamber do not communicate.

By using the technical scheme provided by the application, the overflow valve is not easy to damage.

Drawings

Exemplary embodiments of the present application will be described in detail below with reference to the attached drawings, it being understood that the following description of the embodiments is only for the purpose of explanation and not limitation of the scope of the present application, and in the accompanying drawings:

FIG. 1 is a plan cross-sectional view of a prior art relief valve;

FIG. 2 is a plan cross-sectional view of an embodiment of a relief valve of the present application with portions of the components removed to show the configuration of the valve chamber.

FIG. 3 is a plan sectional view of an embodiment of the relief valve of the present application to show the overall internal structure of the relief valve.

List of reference numerals:

valve body 10

Valve cavity 11

Piston chamber 12

Spring chamber 13

Damper chamber 14

Through hole 15

Liquid collection chamber 16

Seat surface 17

Valve piston 20

Piston rod 21

Piston head 22

Center hole 23

Pores 24

Piston tail face 25

Valve elastic member 30

Valve plug 40

Detailed Description

It should be understood that the drawings are for purposes of illustration only and that the dimensions, proportions and number of parts are not to be construed as limiting the application.

Referring to fig. 2 and 3, an overflow valve according to an embodiment of the present application includes a valve body 10, a valve piston 20, a valve elastic member 30, and a valve plug 40. The valve body 10 is internally provided with a valve cavity 11 which comprises a piston cavity 12 and an elastic piece cavity 13 which are communicated. The piston 20 comprises a piston rod 21 and a piston head 22, and the end surface of the piston rod 21 far away from the piston head 22 is a piston tail surface 25. The valve elastic member 30 is elastically pre-compressed in the elastic member chamber 13 such that one end thereof abuts against the piston head 22 and the other end thereof abuts against the valve plug 40. The valve plug 40 may be omitted in other embodiments where the valve elastic member 30 needs to be secured to other portions of the valve body 10.

In some embodiments including this embodiment, the piston cavity 12 and the elastic member cavity 13 are both cylindrical structures, and the radius of the elastic member cavity 13 is larger than that 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 chamber 12, and the piston rod 21 has a central bore 23 extending from the piston tail surface 25 in the direction of the piston head 22, and the central bore 23 does not extend to the piston head 22. The piston rod 21 has a fine hole 24 communicating with the center hole 23 and penetrating the piston rod 21. When the piston tail surface 25 is not under the liquid pressure, the fine hole 24 is not communicated with the elastic member cavity 13, and when the piston rod 21 moves to the direction of the elastic member cavity 13 for a certain distance, the fine hole 24 is communicated with the elastic member cavity 13.

The valve body 10 has a through hole 15 penetrating to the piston chamber 12. The valve body 10 has a seat surface 17 at a junction between the piston chamber 12 and the elastic material chamber 13, and when the piston end surface 25 is not subjected to the external hydraulic pressure, the piston rod 21 is disposed in the piston chamber 12, and the piston head 22 is disposed in the elastic material chamber 13 and abuts against the seat surface 17. The valve chamber 11 further includes a damper chamber 14 at the other end of the piston chamber 12 and communicating with the piston chamber 12. The profile of the damping chamber 14 is a truncated cone structure that increases in cross section perpendicular to the central axis of the relief valve in the direction toward the piston tail face 25. Between the damping chamber 14 and the piston chamber 12 there is a liquid collecting chamber 16 with the same circumferential inner contour as the piston chamber 12.

In this embodiment, the valve elastic member 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, and the valve spring is in a compressed state when installed in the relief valve.

Although not shown in the drawings, the valve body 10 includes a communication hole (not shown) penetrating to the elastic member chamber 13 in some embodiments of the present invention.

When the piston tail surface 25 is not subjected to the hydraulic pressure or the hydraulic pressure to which it is subjected is smaller than the elastic force of the valve spring, the piston head 22 is seated on the seat surface 17, and the piston rod 21 is located in the piston chamber 12. When the liquid in the liquid collecting cavity 16 is full and the pressure begins to increase until the piston tail surface 25 is subjected to the liquid pressure which is larger than the elastic force of the valve spring, the valve piston 20 is further compressed along the valve cavity 11 towards the valve plug 40, and the piston head 22 moves towards the valve plug 40. When the aforementioned fine hole 24 moves into the elastic member chamber 13, the center hole 23 communicates with the communication hole through the fine hole 24, and the liquid pressure is partially released, thereby smoothing the operation of the valve spring. When the liquid pressure is further increased, the piston rod 21 continues to move towards the valve plug 40 until the piston tail surface 25 is communicated with the through hole 15, the liquid pressure is rapidly released, the liquid in the liquid collecting cavity 16 is rapidly discharged, and therefore the pressure applied to the piston tail surface 25 is smaller than the elastic force of the valve spring. At this time, the piston rod 21 moves in a direction away from the valve plug, after the piston tail surface 25 is in a communication state with the through hole 15, the piston rod 21 continues to move in the direction away from the valve plug, the liquid in the liquid collecting cavity 16 is discharged through the damping cavity 14, and the damping cavity 14 is provided with an opening smaller than the sectional area of the piston cavity 12 in the direction perpendicular to the axial direction of the overflow valve. In the present embodiment, the inner contour of the damping chamber 14 is a circular truncated cone structure that increases in cross section perpendicular to the central axis of the relief valve in the direction of the piston tail surface 25, so that liquid cannot be discharged quickly in the damping chamber 14, the speed of movement of the piston rod 22 is reduced, the speed of seating of the piston head 22 on the seat surface 17 is gentle, and damage to the valve elastic piece and the seat surface and the piston head in the relief valve can be reduced.

It will be appreciated that the configuration of the damping chamber 14 may be other configurations in other embodiments, for example, the damping chamber 14 may be a bore having a smaller cross-sectional area than the piston chamber in a direction perpendicular to the axis of the spill valve. A stepped hole having a large area in the direction facing the piston rear surface 25 may be used.

It will be appreciated that although in this embodiment the piston chamber, spring chamber, piston rod and fluid collection chamber are all cylindrical in configuration, in other embodiments they may be wholly or partially of other configurations.

Synthesize the aforesaid, the part that provides the buffering and play the protection overflow valve when the damping chamber of this application sets up and makes the valve piston take a seat rapidly under the valve spring effect reduces the damage.

Claims

1. An overflow valve comprises a valve body (10), a valve piston (20) and a valve elastic piece (30), wherein a valve cavity (11) comprising a piston cavity (12) and an elastic piece cavity (13) which are communicated with each other is formed in the valve body (10), the piston (20) comprises a piston rod (21) and a piston head (22), the end face, far away from the piston head (22), of the piston rod (21) is a piston tail face (25), one end of the valve elastic piece (30) in the elastic piece cavity (13) is pressed against the piston head (22), the circumferential outer contour of the piston rod (21) is the same as the circumferential inner contour of the piston cavity (12), a through hole (15) penetrating through the piston cavity (12) is formed in the valve body (10), a seat face (17) is formed in the joint of the piston cavity (12) and the elastic piece cavity (13), and when the piston tail face (25) is not pressed by external liquid, the overflow valve is characterized in that the valve cavity (11) further comprises a damping cavity (14) which is arranged at the other end of the piston cavity (12) and communicated with the piston cavity (12), and the damping cavity (14) is provided with an opening which is smaller than the sectional area of the piston cavity (12) in the direction perpendicular to the axial line of the overflow valve.

2. The relief valve of claim 1 wherein the damping chamber (14) is external to the piston tail face (25) away from the piston head (22) when the piston tail face (25) is free of fluid pressure.

3. The relief valve according to claim 1, wherein the contour of the damping chamber (14) is a truncated cone structure having an increasing cross-sectional area perpendicular to the central axis of the relief valve in the direction toward the piston tail face (25), or is a hole having a smaller cross-sectional area than the piston chamber in the direction perpendicular to the axial direction of the relief valve, or is a stepped hole having a larger cross-sectional area in the direction near the piston tail face (25).

4. The excess flow valve of claim 1 having a valve plug (40) at the end of the valve spring remote from the piston rod (21).

5. The excess-flow valve according to claim 1, characterized in that between the damping chamber (14) and the piston chamber (12) there is a liquid collecting chamber (16) having the same circumferential inner contour as the piston chamber (12).

6. The excess-flow valve according to claim 1, characterized in that the piston chamber (12), the spring chamber (13) and the collecting chamber (16) each have a cylindrical inner contour.

7. The excess flow valve according to any one of claims 1 or 6, wherein the valve elastic member is a valve spring.

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

9. The excess flow valve according to claim 1 or 8, characterized in that the piston rod (21) has a central bore (23) extending from the piston tail face (25) in the direction of the piston head (22), the central bore (23) not extending through to the piston head (22).

10. The excess flow valve according to claim 1 or 8, characterized in that the piston rod (21) has a fine hole (24) communicating with the central bore (23) and penetrating the piston rod (21), the fine hole (24) not communicating with the resilient member chamber (13) when the piston tail surface (25) is free from the liquid pressure.