SU608012A1 - Electrohydraulic proportional valve - Google Patents

Description

(54) ELECTRO-HYDRAULIC PROPORTIONAL VALVE

The invention relates to the field of electro-hydraulic control and regulation systems and can be used in various machines and mechanisms with unified remote control, in particular, in pressure and flow controllers for variable feed pumps in safety and reduction valves as a control element in various position control schemes , force or speed, like a pressure relief valve for systems,

An electropneumatic servo drive with feedback on the speed and position of the output link is known. This drive is controlled by a two-stage differential type electropneumatic amplifier, in which the first stage of force is implemented on known devices such as a nozzle-damper, where the equilibrium condition is expressed by: equation.

Rzl-1S lH 25dr

whereES is the total mechanical rigidity of the electromechanical transform &

bodies and feedback systems, reduced to the nozzle axis l.

To ensure high linearity of the output parameter of this valve, it is necessary that i 2XdR.

In a known valve, high linearity is maintained by reducing hydraulic rigidity and increasing mechanical, however, linearity is maintained in a very narrow range.

Closest to the invention is an electro-hydraulic proportional valve containing an electromechanical transducer with a cow which is a variable choke valve, the nozzle of which is connected to the inter-throttle chamber of the housing connected to the power channel and the output channel 2J.

However, the operation of this type of valves with low flow rates of the control fluid characterizes the dependence of the output pressure in the control chamber, located between constant and variable throttles, on the fluctuation of the supply pressure; large non-linearity of the characteristics of the change in the output pressure as a function of the change in the input signal. Moreover, when the input electric signals of opposite polarity of the valve do not have symmetrical characteristics on the output pressure, this makes it difficult to use valves as control elements in various control and regulation schemes position, speed, effort. The aim of the invention is to reduce the non-linearity of the valve. This is achieved; The fact that in the proposed valve there is installed a feedback element made in the form of a sleeve with a ball connected with a variable choke valve, and the cavity of the sleeve is connected to the inter-throttling chamber. In addition, a bias spring can be installed in the valve, located on between the damper and the housing. FIG. 1 shows an electro-hydraulic proportional valve; in fig. 2 is a section along the line A-A of FIG. one; in fig. 3 is a section along BB, FIG. 1. The valve contains an electromechanical transducer (EMI) 1 with a flare 2 acting as a flap of the alternating throttle formed by the flap — flap 2, SOPL 3 and a ball 4. The nozzle 3 is installed in the housing 5, the EMI is attached to the housing 5. Before the nozzle 3 the ball 4 is located. Behind the constant choke formed by the throttle washers 6, which are pressed by the screw, 7, there is an intercrossed cameo. A feedback element 8, made in the form of a sleeve b, inside which a ball 10 is placed, is installed in the chamber. The sleeve is pressed by a limiter 11. In the case 5 there is an additional adjustment element in the form of a bias spring 12 and a nut 13. The valve operates as follows. When the input electrical signal is applied, the bark 2 of the EMI moves, the gap between the ball 4 and the nozzle 3 changes, which, due to the low mechanical rigidity of the core, leads to a proportion of the borehole and iomeiiiiiKKi to the pressure in the inter throttling chamber. At the same time, the control pressure varies. Under the ball Yu, which transmits a force to the EMF measles, where it is summed algebraically with the force on the cortex from an electromagnetic effect in the presence of an input signal. When the supply pressure fluctuates, the control pressure under the ball Yu changes, which disrupts the balance of forces on the core 2 Vi leads to a change in the working gap between the ball 4 and the nozzle 3. At the same time, the pressure in the chamber slightly changes, compensating for the disturbing effect that and stabilizes control pressure. Thus, the greater the overall efficiency., The area of the nozzle and the ball and the less mechanical rigidity of the core, the higher the degree of stabilization and the smaller the nonlinearity of the static characteristic. Inventions Formulas An electro-hydraulic proportional valve containing an electromechanical transducer with a bore that is a variable throttle damper, the nozzle of which is connected to the inter-throttle chamber of the housing connected to the supply channel and output channel, in order to reduce the non-linearity of the valve A feedback element made in the form of a sleeve with a ball connected to a variable throttle flap is installed, the cavity is connected to the inter-throttling chamber. 2. Valve according to claim 1, characterized in that it contains a bias spring located between the flap and the housing. Sources of information taken into account in the examination: 1. US patent number ZO40715, cl. 91-51, 1962. 2.Vickers Catalog, 1971, p. one.

6-B