RU1800152C - Spool hydraulic distributor - Google Patents

Abstract

SUMMARY OF THE INVENTION: One of the seats has windows for supplying and discharging liquid. A flat spool is placed between the saddles with the possibility of reciprocating movement, in which channels are made for communication with the windows. Unloading cavities are in communication with additional channels. Cavities and channels are made in the spool. The cavities are located on both sides of the spool and are interconnected by additional channels. 3 ill.

Description

The invention relates to mechanical engineering and can be used in hydraulic control devices and for regulating fluid flow.

A known design of a control valve comprising a spool of a flat shape with distribution channels which is pressed against a seat by a piston, which in turn is pressed against an opposite seat through a plain bearing.

The aim of the invention is to reduce friction between the spool and seats and increase the accuracy of regulating fluid flow.

In FIG. 1 shows a spool valve with a spool having distribution channels on one side and windows on one of the seats; in FIG. 2 - spool valve with a spool having distribution channels on both sides and windows on both saddles; in FIG. 3 is a diagram of the pressure distribution in the gap between the spool and seats.

The spool valve contains the spool (1), made in the form

a flat element and having at least one channel for regulating the fluid flow (2) and two discharge cavities (3 and 4) connected to at least one additional channel (5) on its two opposite sides. The area defined by the discharge cavities 3 on the high pressure side of FIG. 1 or from the side of the distribution channels for FIG. 2 is smaller than the area defined by the discharge cavities 4 from the low pressure side. The spool itself is positioned for reciprocating movement between two saddles (6 and 7). at least one of the seats has windows (8) for supplying and discharging liquid.

The operation of the spool is carried out as follows.

When pressure is applied to the windows 8, and through them to the channels 2, due to leaks in the discharge cavities 3 and 4, a certain pressure is established due to leakage of liquid through the gaps between the spool and seats and determined by the location of the discharge cavities and the size of the gap. Because unloaded

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the viscous cavities 3 and 4 are connected by additional channels, the pressure in them is redistributed so that it becomes equal. The pressure depends on the size of the gaps between the spool 1 and the seats 6 and 7. So, if the gap on one side (for example, from the higher pressure side for Fig. 2 or. From the distribution channels for Fig. 1) is greater than on the other hand, the pressure in the discharge planes will be determined by leaks on the side of the spool where the clearance is greater. The resulting force acting on the spool, on each side, is determined by the pressure in the distribution channels and the average pressure in the gap between the channels and seats. Because the pressure in the discharge cavities is quite high (determined by leaks on the high pressure side), and the area defined by the discharge cavities on the low pressure side is greater, the resulting force on the high pressure side, and the spool is shifted towards the alignment of the gaps. In this case, the pressure in the cavities will decrease, since leaks on the low pressure side will have a greater effect, and on the high side, less. The resulting force on the high pressure side decreases more slowly, because here the pressure force in the distribution channels has a significant effect, and the area defined by the discharge cavities is smaller. At a certain position of the spool, the forces acting on it are compared and its movement stops. If for any reason the clearance on the low pressure side is greater, the pressure in the discharge cavities drops even more, and the force on the high pressure side is greater. than with

low side and spool will move to high pressure side. The dimensions and location of the discharge cavities should preferably be selected so that the clearance between

the spool and saddles in equilibrium were the same on both sides. .. Zolotnik - with distribution channels - - on the one hand (Fig. 1) works the same for any direction of flow; at

spool with distribution channels. on both sides (Fig. 2), when the flow direction is changed, there is no full compensation of forces from pressure, but due to the unloading action, operability is preserved. : .... -

The application of the present invention will reduce friction between the spool and seats and increase the accuracy of fluid flow control.

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Claims (1)

SUMMARY OF THE INVENTION : Spool valve containing two seats with at least one of their windows for a liquid inlet and outlet located between the saddles with the possibility of reciprocating movement of a flat spool with channels made in it for communication with windows. For inlet and outlet liquids and unloading cavities in communication with additional channels, which is characterized in that, in order to reduce friction between the spool and seats and improve the accuracy of regulating the fluid flow, unloading cavities and additional channels are made in the spool, while unloading cavities are located on both sides spool and interconnected by additional channels. / L NPO Hit the canon