Balance valve and engineering machine

Abstract

The invention relates to a balance valve and an engineering machine. The balance valve comprises a loading cavity, an oil inlet cavity and a balance valve body core, wherein a first oil duct for communicating the loading cavity with the oil inlet cavity is arranged in the balance valve; the balance valve body core is provided with a second oil duct for communicating the loading cavity with the oil inlet cavity; when the balance valve is reversely opened, the initial section of the motion stroke of the balance valve body core is a cover stroke; and in the cover stroke, the first oil duct is closed, so that oil flows back through the second oil duct, wherein the through flow of the second oil duct is smaller than that of the first oil duct. In the cover stroke, the first oil duct is closed, the oil flows back through the second oil duct, and the through flow of the second oil duct is smaller than that of the first oil duct, thereby preventing instantaneous change of the pressure in the balance valve loading cavity and enhancing the jogging property of the system. The balance valve can avoid frequent opening and closing and prevent the hoisting system from being subjected to action impact, whipping or other phenomena, thereby enhancing the stability of the balance valve and system.

Description

technical field [0001] The invention relates to the technical field of construction machinery, in particular to a balance valve and construction machinery. Background technique [0002] Hydraulic drive systems are widely used in construction machinery. When the load is lowered, the luffing, telescopic and other mechanisms go down at an overspeed speed, and the phenomenon of overtaking the load often occurs. Overloading means that when the actuator drives the vertical moving part to go down, the direction of the load force is the same as the direction of motion. , the load force will accelerate the movement of the actuator. In order to avoid the overload phenomenon, a balance circuit composed of balance valves must be installed in the system. [0003] As a regulating valve group with a special locking function, the balance valve is widely used in construction machinery, especially mobile crane equipment. Generally speaking, in order to ensure the safety and stability of the...

AI Technical Summary

Problems solved by technology

[0008] To sum up, the existing balance valve is controlled by the principle of throttling at the valve port. In the system response stage, if the flow at port A and port B is unbalanced, the pressure will change greatly, and sometimes there will be a jump change, which will cause the valve port of the balance valve to open. The speed changes quickly, the opening amount is overshoot, the system has shock and vibration, and it is difficult to ensure the smooth operation of the system. This phenomenon is more obvious when the crane is operating, and it is more likely to cause danger.

The micro-motion effect of the existing balance valve control system is poor, the control performance is poor, and it is difficult to meet some high-demand hoisting conditions

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