Negative flow hydraulic control oil circuit and hydraulic system and excavator

Abstract

The invention relates to a hydraulic control oil circuit, and provides a negative flow hydraulic control oil circuit in order to solve the problems of high oil consumption and high oil temperature caused by large overflow flow when a main pump operates at high pressure and full power in an existing negative flow hydraulic control system. The negative flow hydraulic control oil circuit comprises amain pump, a main control valve and a pressure shutoff valve. A neutral position oil returning throttle hole is formed in a neutral position oil returning channel of the main control valve, and the pressure cut-off valve includes a normally closed hydraulic control reversing valve, a pressure reducing valve and a shuttle valve. The liquid control end of the hydraulic control reversing valve is connected with the oil inlet end, and a pump opening of the main pump is connected with the oil inlet end through a pipe. The oil inlet end of the pressure reducing valve is connected with the oil outletend of the hydraulic control reversing valve, and the oil outlet end of the pressure reducing valve is connected with the second oil inlet end of the shuttle valve. The first oil inlet end of the shuttle valve is connected with the oil inlet end of the neutral position oil returning throttle hole, and a negative flow displacement controller of a main pump displacement regulator is connected withthe oil outlet end of the shuttle valve. According to the negative flow hydraulic control oil circuit, the displacement of the main pump is reduced when a machine operates under high pressure conditions, so that the main pump can operate at low power, high flow overflow loss is avoid, energy is saved, and the oil temperature is reduced.

Description

technical field [0001] The invention relates to a hydraulic control oil circuit, more specifically, to a negative flow hydraulic control oil circuit, a hydraulic system and an excavator. Background technique [0002] Negative flow hydraulic control hydraulic system is widely used in medium and large excavators and is a very mature hydraulic system. It is characterized in that an orifice is set on the middle oil return channel of the main control valve, and the oil passes through the orifice to generate a pressure difference. Lead the pressure in front of the orifice to the negative flow displacement controller of the displacement regulator of the hydraulic pump to control the displacement of the hydraulic pump to prevent large air flow loss in the system. When the whole machine is in standby operation (or the operator is doing fine work), the hydraulic oil (or remaining hydraulic oil) output by the main pump flows back to the oil tank through the middle oil return channel of...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a negative flow hydraulic control hydraulic system for the problem that the main pump in the existing negative flow hydraulic control hydraulic system generates a large system overflow flow when the main pump is running at high pressure and full power, resulting in high fuel consumption. The negative flow hydraulic control oil circuit of the hydraulic system makes the negative flow hydraulic control hydraulic system reduce the power and displacement of the main pump when the hydraulic system is under high pressure conditions, reducing overflow loss and energy consumption

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