Hydraulic circuit capable of accurately controlling lifting height of movable arm of excavator

Abstract

The invention discloses a hydraulic circuit capable of accurately controlling a lifting height of a movable arm of an excavator. The hydraulic circuit comprises a pilot-operated pump, a pilot-operated control valve, a limiting control valve, a main pump, a main hydraulic control valve and a movable arm oil cylinder, wherein an output end of the pilot-operated pump is communicated with an oil inlet of the pilot-operated control valve; a first oil outlet of the pilot-operated control valve is communicated with a first hydraulic control opening of the main hydraulic control valve through a limiting control valve; a second oil outlet of the pilot-operated control valve is communicated with a second hydraulic control opening of the main hydraulic control valve; an output end of the main pump is communicated with an oil inlet of the main hydraulic control valve; two oil outlets of the main hydraulic control valve are respectively communicated to front and rear cavities of the movable arm oil cylinder; a limiting pressing plate is arranged at one side of a piston rod of the movable arm oil cylinder and corresponds to the position of a contact of the limiting control valve; and when the movable arm is lifted to the pre-set height, the limiting pressing plate is pressed on the contact of the limiting control valve to lock the movable arm. The movable arm of the excavator is accurately positioned, the labor intensity is reduced and the working efficiency of the excavator is improved.

Description

technical field [0001] The invention relates to an excavator hydraulic circuit, in particular to an excavator arm lifting hydraulic circuit, which belongs to the technical field of engineering machinery. Background technique [0002] The boom is an important part of the working device of the hydraulic excavator. The hydraulic excavator controls the swing of the boom and the rotation of the bucket through the hydraulic circuit to complete the excavation. With the improvement of people's functional requirements for excavators, it is necessary to replace the extended boom for the excavator, or to complete the excavation within a limited space, but the lifting height of the existing excavator boom is mainly controlled manually by the operator visually. When reaching the predetermined height, the manual control makes the boom cylinder slow down the expansion and contraction speed, so that it slowly rises to the predetermined height. Due to the visual error, it is impossible to a...

AI Technical Summary

Problems solved by technology

With the improvement of people's functional requirements for excavators, it is necessary to replace the extended boom for the excavator, or to complete the excavation within a limited space, but the lifting height of the existing excavator boom is mainly controlled manually by the operator visually. When reaching the predetermined height, the manual control makes the boom cylinder slow down the expansion and contraction speed, so that it slowly rises to the predetermined height. Due to the visual error, it is impossible to accurately control the retraction stroke of the boom cylinder, and the lifting positioning of the excavator boom is not accurate, and it is often biased. High or low, the operator's labor intensity is high, and the control action is slow

In addition, in order to adapt to specific tasks under various working conditions, it is often necessary to replace the boom cylinders with different strokes, which is cumbersome and reduces the working efficiency of the hydraulic excavator

Images