A small displacement and small pressure control loop of a variable pump and its control method

Abstract

The invention discloses a small discharge capacity and small pressure control loop of a variable pump and a control method thereof. An electronic control end of an electromagnetic valve, an electronic control end of a proportional pressure relief valve and an engine speed sensor are respectively connected with a controller; an energy accumulator is connected with a guide pump of the control loop of the variable pump through a first electromagnetic valve and a one-way valve; the energy accumulator is connected with a discharge capacity drive loop hydraulic fluid port of the control loop of the variable pump through the first electromagnetic valve and the proportional pressure relief valve; the energy accumulator is connected with a discharge capacity control hydraulic fluid port of the control loop of the variable pump through a second electromagnetic valve and a second one-way valve; a third electromagnetic valve and a fourth electromagnetic valve is connected with an oil outlet of the control loop of the variable pump; and the engine speed sensor detects the rotate speed of an output shaft connecting with an engine and the variable pump. According to the invention, the control on the minimum discharge capacity and the minimum pressure of the variable pump can be realized, and starting load of the engine and oil consumption during the operation can be effectively reduced.

Description

technical field [0001] The invention relates to a control loop of a variable displacement pump, in particular to a small displacement and small pressure control loop of a variable displacement pump, and also relates to a control method of the small displacement and low pressure control loop of the variable displacement pump. Background technique [0002] Under normal circumstances, the excavator relies on the hydraulic system to convert the mechanical energy of the engine into the movement of the working device, such as the raising and lowering of the working arm, retracting or swinging outward, and the rotation of the whole vehicle. The energy conversion of the whole process is realized by driving the hydraulic cylinder and the hydraulic motor through the hydraulic pump. Usually, the engine needs to carry the hydraulic pump to start or run. The product of the displacement of the hydraulic pump and the outlet pressure determines the engine start or run The size of the load t...

AI Technical Summary

Problems solved by technology

The energy conversion of the whole process is realized by driving the hydraulic cylinder and the hydraulic motor through the hydraulic pump. Usually, the engine needs to carry the hydraulic pump to start or run. The product of the displacement of the hydraulic pump and the outlet pressure determines the engine start or run The size of the load torque value, in the application practice of the excavator, the load brought by the hydraulic pump to the engine on the one hand increases the current of the starter motor and the burden on the battery when the engine is started, and at the same time brings difficulty in starting under low temperature conditions. problem; on the other hand, this load causes energy losses in engine operation

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