Telescopic boom hydraulic system, crane boom system and crane

Abstract

The invention discloses a telescopic boom hydraulic system, a crane boom system and a crane. The telescopic boom hydraulic system comprises a telescopic oil cylinder which is used for the extension and retraction control of a crane telescopic boom, and a first balance valve and a second balance valve which are connected with the hydraulic oil way of the telescopic oil cylinder in parallel and are used for controlling the retraction pressure of the telescopic oil cylinder. The throttling inlets of the first balance valve and the second balance valve are communicated with the rodless chamber of the telescopic oil cylinder. The throttling outlets of the first balance valve and the second balance valve are communicated with a return oil way. The flow of the first balance valve is smaller than or equal to the flow of the second balance valve. The working damping of the first balance valve is smaller than the working damping of the second balance valve. After the two balance valves are successively opened, the balance valve with smaller flow can realize low-speed stable operation at the early retraction stage of the telescopic boom, and the balance valve with larger flow can facilitate the telescopic oil cylinder to enter a faster operation stage after the stable operation of the telescopic oil cylinder is realized.

Description

technical field [0001] The invention relates to the technical field of hoisting control, in particular to a telescopic arm hydraulic system, a crane arm system and a crane. Background technique [0002] Crane is a typical hoisting machinery, which is widely used in various fields of economic construction. [0003] Among them, the boom system of the crane is an important part of the crane. The length of the boom in the boom system of the crane is an important parameter to measure the operating performance of the crane. The longest length after exiting. The longer the jib arm length, the better the crane's operating performance. Taking the telescopic jib crane as an example, several prior art methods for increasing the jib arm length will be introduced. [0004] At present, the main way to increase the length of the boom is to reduce the overlap ratio between adjacent boom sections, that is, after the telescopic boom is fully extended, the overlap between the boom sections i...

AI Technical Summary

Problems solved by technology

However, the overlapping length of the telescopic arm is reduced. When the telescopic arm is fully extended, its deformation is relatively large, which often easily leads to the problem of retraction vibration during the retraction process of the telescopic arm. Practice has proved that if the telescopic arm retracts initially Vibration is generated, so that the boom will vibrate during the entire retraction process, causing vibration of the steel wire rope and other components connected to the telescopic boom, which in turn causes the vibration of the whole machine and affects the stability of the lifting operation.

[0006] The size of the retraction vibration is also very important to the hydraulic system of the telescopic boom that controls the movement of the telescopic boom. At present, the retraction control of the telescopic boom is mainly realized through the hydraulic system of the telescopic boom. The hydraulic system of the telescopic boom includes telescopic The oil cylinder and the hydraulic components that control the telescopic cylinder. The hydraulic components mainly include a reversing valve and at least one balance valve with a certain opening characteristic. Especially for large-tonnage cranes, the hydraulic system of the telescopic arm adopts a parallel connection of multiple balance valves to control the pressure. The flow and flow are the same, regardless of the order and priority, that is, the response characteristics of several parallel balance valves are the same, and the consistency of the action of the telescopic cylinder at the moment when each balance valve is opened at the same time is relatively poor.

[0007] In this way, the pressure in the retraction chamber of the telescopic cylinder increases sharply, and the peak value of the pressure is relatively high. Once the balance valve is opened, the hydraulic oil in the retraction chamber is released, and the pressure drops sharply, resulting in relatively large fluctuations in the oil pressure of the control oil circuit of the balance valve, that is The process of pressure overshoot is slow, resulting in unstable hydraulic system of the telescopic arm, shaking of the telescopic arm or sinking of the telescopic cylinder during the retraction stage, and instability of the telescopic arm system

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