Control device for pilot spool

Abstract

The invention relates to a control device for a pilot spool. The control device for the pilot spool comprises a no-load control oil line and at least one load control oil line which are arranged between an oil inlet and an oil outlet and are connected in parallel, wherein the no-load control oil line is communicated with a first control containing cavity through a first control oil opening; the load control oil line is communicated with a second control containing cavity through a second control oil opening; the load control oil line is provided with a variable damping and a variable cavity; when the pressure of the oil inlet is increased to push a valve element of a main valve of the pilot spool to move by a preset distance, part of pressure oil entering from the oil inlet partially enters the first control containing cavity through the no-load control oil line, the other part of the pressure oil entering from the oil inlet partially enters the second control containing cavity through the variable damping and the variable cavity in sequence, and the valve element of the main valve of the pilot spool moves. According to the device, the pilot-level pressure fluctuation can be eliminated in the opening process of the spool, the fluctuation frequency of the displacement of the valve element of the main valve is slowed down in the starting process, the opening process of the main element of the main valve is optimized, and the control device has good control stability and accuracy.

Description

technical field [0001] The invention relates to the field of engineering machinery, in particular to a control device for a pilot slide valve. Background technique [0002] The hydraulic control valve is a control element in the hydraulic system, which is used to control the pressure, flow and flow direction of the fluid in the hydraulic system to meet the different action requirements of power actuators such as hydraulic cylinders and hydraulic motors. The pilot control valve is a control mechanism that manipulates other hydraulic control valves or components, and its control power is often small. Usually, after the pilot spool valve is opened, the pressure oil acts on the main valve of the pilot spool valve after passing through the oil circuit of the pilot spool valve. On the spool, push the main valve to move. The pilot stage (i.e. pilot spool valve) designed with a slide valve structure has the advantages of good guiding conditions and sensitive response. However, due ...

AI Technical Summary

Problems solved by technology

[0004] Due to the small volume of the control oil circuit in the prior art, when the resistance values ​​of the first fixed damper R1 and the second fixed damper R2 are adjusted, the control oil port of the main valve spool of the controlled spool valve 1' will build up pressure. The process is still fast, the pressure cushioning effect is not obvious, and the fluctuation of the pilot stage pressure of the slide valve will cause the hydraulic shock of the hydraulic system, which will cause damage to the hydraulic components and bring unpredictable hydraulic failures and potential safety hazards

[0005] In addition, in order to alleviate the pressure shock, the setting value of the damping is often small or a multi-stage liquid bridge is used. When the oil is polluted, it will easily lead to the blockage of the control network; and because the liquid resistance of the liquid bridge is small, the heat will be serious in frequent use occasions , will affect control performance and component life

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