A constant pressure control device and control method for a hydraulic pump

Abstract

The invention discloses a constant pressure control device and a control method for a hydraulic pump. Among them, the oil inlet of the fine filter is connected with the oil discharge port of the hydraulic pump, the oil outlet of the fine filter is connected with the P port of the constant pressure control valve and the rodless chamber of the small variable piston at the same time, and the A port of the constant pressure control valve is connected with the damping valve The P port is connected, the T port of the constant pressure control valve is connected with the T port of the shock absorber valve and the oil tank at the same time, the control port of the constant pressure control valve is connected with the P port of the constant pressure control valve through its internal fixed damping, and the A port of the shock absorber valve is connected with the large variable piston The rodless chamber is connected; the feedback rod is fixedly connected with the small variable piston, so that when the pressure at the oil discharge port of the hydraulic pump is higher than the proportional spring setting pressure of the constant pressure control valve, the feedback rod can move to the shock absorber driven by the small variable piston. The valve spool contacts and pushes the spool to move to the position where P port and T port of the damping valve are connected; when the pressure at the oil discharge port of the hydraulic pump is lower than the proportional spring setting pressure of the constant pressure control valve, the feedback rod can be connected with The damping valve spool is separated.

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 method ...

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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