Constant-pressure control device and method for hydraulic pump

Abstract

The invention discloses a constant-pressure control device and method for a hydraulic pump. An oil inlet of a fine filter is communicated with an oil discharge port of the hydraulic pump, an oil outlet of the fine filter is communicated with a constant-pressure control valve port P and a rodless cavity of a small variable piston at the same time, a constant-pressure control valve port A is communicated with a shock reducing valve port P, a constant-pressure control valve port T is communicated with a shock reducing valve port T and an oil tank at the same time, a constant-pressure control valve control port is communicated with the constant-pressure control valve port P through internal fixing damping, and a shock reducing valve port A is communicated with a rodless cavity of a large variable piston; a feedback rod is fixedly connected with the small variable piston, so that when pressure at the oil discharge port of the hydraulic pump is higher than pressure set by a proportional spring of a constant-pressure control valve, the feedback rod can be driven by the small variable piston to move to contact with a valve spool of a shock reducing valve and push the valve spool to move to the communicating station of the shock reducing valve port P and the shock reducing valve port T; when pressure at the oil discharge port of the hydraulic pump is lower than pressure set by the proportional spring of the constant-pressure control valve, the feedback rod can be separated from the valve spool of the shock reducing valve.

Description

technical field [0001] The invention relates to a hydraulic pump constant pressure control device and a control method, belonging to the technical field of hydraulic control. Background technique [0002] The hydraulic pump is the core component of the hydraulic system, and its performance directly affects the overall performance of the hydraulic system. With the development of hydraulic technology, the working pressure of the hydraulic system is getting higher and higher, and the output flow is getting bigger and bigger. Therefore, more stringent requirements are put forward for the response speed and stability of the hydraulic pump when the system is overloaded. In order to reduce the pressure overload damage of the hydraulic pump and hydraulic system components when the hydraulic pump is applied to the system overload, the constant pressure control method is often used to protect the hydraulic pump from overload. [0003] The traditional constant pressure control me...

AI Technical Summary

Problems solved by technology

This scheme can achieve hydraulic system overload protection through reasonable hydraulic resistance matching, but there are two deficiencies: first, when the hydraulic pump is in the overload protection state, due to the existence of fixed liquid resistance, part of the pilot control hydraulic oil leaks through the fixed liquid resistance To the oil tank, the piston cavity of the variable piston is not fully acted on to reduce the pump displacement to curb the increase of system pressure. Therefore, the response speed of the hydraulic pump to the overload of the hydraulic system is weakened by the fixed hydraulic resistance; secondly, the damping from the pilot control system From the point of view, in the traditional C-type pilot hydraulic half-bridge control mode, the stability and quickness of the pilot variable control system of the hydraulic pump are restricted by the fixed damping, that is, when the fixed damping is increased, the stability of the constant pressure regulation process increases, and the constant pressure adjustment process increases. The pressure adjustment process is stable, but the response speed of the pilot variable control system of the hydraulic pump becomes slower, and the constant pressure adjustment process takes longer, thus causing damage to the hydraulic pump itself and system components, and reducing the fixed damping, the effect is opposite

It can be seen from the above that there is room for optimization and improvement in the traditional constant pressure control method of this pump

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