CN2450424Y

CN2450424Y - Leading overflow valve

Info

Publication number: CN2450424Y
Application number: CN 00225961
Authority: CN
Inventors: 胡燕平; 刘德顺; 陈安华; 彭佑多; 康煜华
Original assignee: XIANGTAN POLYTECHNICAL COLLEGE
Current assignee: XIANGTAN POLYTECHNICAL COLLEGE
Priority date: 2000-11-14
Filing date: 2000-11-14
Publication date: 2001-09-26
Anticipated expiration: 2010-11-14

Abstract

The utility model relates to a guide overflow valve. On the basis of a fixed hydraulic resistor and a variable hydraulic resistor of an original overflow valve, a fixed hydraulic resistor is arranged on a guide return circuit. A valve core of the guide valve of the utility model has stable guide, the movement stability of the guide valve is good, and noise is low. The utility model can also increase the constant pressure precision and the work efficiency of a hydraulic system, and is an ideal substitute of the widely used overflow valves which use hydraulic resistor half-bridges as guide control networks.

Description

Pilot operated compound relief valve

The utility model relates to a kind of relief valve, particularly a kind of pilot operated compound relief valve.

At present, existing relief valve adopts half-bridge liquid resistance network structure more, it is by a fixer resistance and the liquid resistance network that variable liquid resistance is constituted, it has only a fixer resistance in the guide loop, pilot valve is a cone valve, between poppet valve core and valve seat, form variable liquid resistance, when spillway discharge increases, the aperture of poppet port and primary valve all will increase, spring force and steady-state fluid force increase, so inlet pressure must increase, and spillway discharge is big more, inlet pressure is also big more, so this valve has positive stable state override pressure.This kind relief valve can not hinder different its stable state override pressure, the bad adaptability of regulating arbitrarily of network parameter according to liquid.

The purpose of this utility model is to provide a kind of pilot operated compound relief valve, and it can hinder the difference of network parameter according to liquid, changes the steady-state characteristic of pressure controlled valve.

The purpose of this utility model is achieved through the following channels: pilot operated compound relief valve, it comprises main valve and is fixed on pilot valve on the main valve, the fixer resistance is arranged on the main valve, form variable liquid resistance between guide's spool and the guide's valve seat, this guide's spool front portion is taper, pyramidal front end has screw thread, and piston is fixed on guide's spool by nut and cone, above-mentioned guide's spool, piston, nut are formed the pilot valve core assembly, this pilot valve core assembly formerly moves freely in the guide valve seat, and the fixer resistance screw that has aperture has been installed in guide's valve body.

The utility model compared with prior art, its advantage is: 1. existing is that the relief valve of guide's control loop always exists positive stable state override pressure with half-bridge liquid resistance network, and the utility model is according to the difference of liquid resistance network parameter, and its stable state override pressure just can be, be zero, also can be for negative; 2. pilot valve core of the present utility model has stable guiding, and pilot valve stability of motions is good, and noise is little; 3. override pressure is setting-pressure accuracy and the working efficiency that zero relief valve can improve hydraulic system; Pilot operated compound relief valve be at present widely used be the alternative of new generation of guide's relief valve of controlling network with liquid resistance half-bridge.

Below in conjunction with figure the utility model is described in further detail:

Fig. 1 is an overall structure schematic representation of the present utility model;

Fig. 2 is the structural representation of the utility model pilot valve and valve seat;

Fig. 3 is the schematic diagram of the utility model pilot operated compound relief valve;

Fig. 4 is the schematic diagram of semibridge system relief valve in the prior art.

The pilot operated compound relief valve structure as shown in Figure 1 and Figure 2, this valve is made up of main valve 2 and pilot valve 3, pilot valve 3 is positioned at above the main valve 2, with four screws pilot valve 3 is fixed on the main valve 2, main valve 2 structures are identical with existing relief valve main valve, the fixer resistance screw 7 that has aperture has been installed in guide's valve body 4, central small hole plays inhibition to the fluid by pilot valve, guide's spool 8 left ends have screw thread, the right-hand member of screw thread is a cone, by nut 11 and cone piston 9 is fixed on guide's spool, piston 9 and guide's spool 8 are integral.Formerly the right-hand member of guide valve core is a poppet valve core, guide's spool 8, and piston 9, elastic washer 10, nut 11 is formed the pilot valve core assembly, and its structure is as shown in Figure 2.But the pilot valve core assembly is guide valve seat 5 interior move left and right formerly, and guide's valve seat 5 usefulness circlips are fixed in guide's valve body 4.

The working principle of this valve such as Fig. 3, it is by three liquid resistance R ₁, R ₂, R ₃Constitute, wherein 1 is R ₁, fixer resistance screw 7 is R ₂, R ₁, R ₂Be the fixer resistance, the valve port between guide's spool 8 and the guide's valve seat 5 is R ₃, R ₃Be variable liquid resistance.Guide's spool 8 of this valve is subjected to liquid resistance R ₂Two pressure P of front and back ₂And P ₃And the pilot valve spring force controls, and its working principle is as follows: when pilot valve is not opened, and liquid resistance R ₁And R ₂There is not fluid to flow through, P ₁=P ₂=P ₃, work as P ₁Rise, when making the hydraulic coupling that acts on the pilot valve left side reach the pilot valve spring force, pilot valve is opened, and fluid passes through R ₁, R ₂Flow back to fuel tank with poppet port, at this moment P ₁＞P ₂＞P ₃, as pressure differential deltap P=P ₁-P ₃When reaching certain value, main valve open, most of flow makes the valve inlet pressure controlled from the primary valve overflow.

The basic structure of existing relief valve as shown in Figure 4, its guide loop has only fixer resistance a 1 (R ₁), pilot valve is a cone valve, forms variable liquid resistance R between poppet valve core and guide's valve seat ₃This liquid resistance network that is made of the resistance of fixer and variable liquid resistance hinders network half-bridge liquid, when spillway discharge increases, the aperture of poppet port and primary valve all will increase, spring force and steady-state fluid force increase, so inlet pressure must increase, and spillway discharge is big more, inlet pressure is also big more, so this valve has positive stable state override pressure.This valve is compared with existing relief valve, and its main distinction is that the guide loop has increased fixer resistance R ₂, changed the structure of guide's spool, make guide's spool two ends P that is stressed ₂And P ₃Common control, the flow that guide's spool passes through are simultaneously also by liquid resistance R ₁And R ₂, at liquid resistance R ₁And R ₂On produce pressure drop Δ P respectively ₁With Δ P ₂, when the pilot valve flow increases, Δ P ₁With Δ P ₂All to increase Δ P ₁Increase and make P ₂Reduce, the power that acts on guide's spool left end reduces, Δ P ₂Increase and make P ₃Reduce, the power that acts on guide's spool right-hand member reduces, and poppet port is to increase or dwindle to depend on Δ P ₁With Δ P ₂The size of increment had both depended on R ₁And R ₂Size, when changing liquid resistance R ₁Or R ₂Orifice size the time, can make pilot operated compound relief valve present three kinds of different flow pressure characteristics.

Claims

1. pilot operated compound relief valve, it comprises main valve [2] and is fixed on pilot valve [3] on the main valve [2], fixer resistance [1] is arranged on the main valve [2], form variable liquid resistance between guide's spool [8] and the guide's valve seat [5], it is characterized in that guide's spool [8] front portion is taper, pyramidal front end has screw thread, and piston [9] is fixed on guide's spool [8] by nut [11] and cone, above-mentioned guide's spool [8], piston [9], nut [11] is formed pilot valve core assembly [15], this pilot valve core assembly [15] formerly moves freely in the guide valve seat [5], and the fixer resistance screw [7] that has aperture has been installed in guide's valve body [4].