Winch hydraulic control system and engineering machinery

Abstract

The invention relates to the technical field of engineering machinery and discloses a winch hydraulic control system and engineering machinery. The winch hydraulic control system for increasing action safety of a winch mechanism of the engineering machinery and effectively preventing safety accidents caused by weight or ladder assembly sliding down during wind brake comprises a winch motor, a motor reversing valve, a winch brake, a hydraulic control reversing valve and a switch control valve. The working oil port of the winch brake is communicated with the working oil port of the hydraulic control reversing valve. The first oil inlet, the second oil inlet and the oil outlet of the switch control valve are respectively the lifting high-pressure oil port and the descending high-pressure oil port of the winch motor and the control oil port of the hydraulic control reversing valve. When the oil pressure at the control oil port is larger than the set working pressure of the hydraulic control reversing valve, the hydraulic control reversing switches from the first working position to the second working position, wherein when the hydraulic control reversing valve is at the first working position, the working oil port of the hydraulic control reversing valve is communicated with the oil outlet, and when the hydraulic control reversing valve is at the second working position, the working oil port of the hydraulic control reversing valve are communicated with the oil inlets.

Description

technical field [0001] The invention relates to the technical field of construction machinery, in particular to a winch hydraulic control system and construction machinery. Background technique [0002] Hoisting is often used in construction machinery. For example, on a crane, hoisting is used to lift heavy objects; on a fire truck, hoisting is used to realize the expansion and contraction of the ladder frame and the lifting of the slide. The driving methods of the winch can be divided into internal combustion engine driving, electric motor driving and hydraulic driving. Among them, the hydraulic driving method is the most widely used due to its large transmission ratio, wide-range stepless speed regulation, compact structure, stable operation, and good overload protection performance. [0003] In the current hoist hydraulic control system, when the hoist motor is running, the hoist brake is in the open state. When the motor electromagnetic reversing valve returns to the neu...

AI Technical Summary

Problems solved by technology

[0004] The defect of the existing technology is that when the winch motor stops running, the opening pressure of the winch brake is relatively low (generally 1.8-2.5MPa), and because the oil return line of the system usually has a certain pressure back pressure P, it is very easy to cause The pressure oil in the hoist brake is not returned smoothly so that the hoist brake cannot be closed in time, causing the hoist brake to be delayed, or, when the hoist brake has been braked, other working oil other than the hoist motor working oil circuit The back pressure P generated in the oil return line of the system when the road action (for example, the luffing cylinder action) 2 , it is very easy to cause the positive pressure of the hoist brake on the hoist to decrease, that is, the braking force of the hoist is less than the braking force of the hoist brake when it is reliably braked, so that heavy objects or ladders slide down and cause safety accidents

[0005] In addition, when the winch motor stops running, the gravity of the suspended weight makes the load pressure P formed between the hoisting oil port of the winch motor and the balance valve. 1 , the back pressure of the oil return line of the system P, P 2 or load pressure P 1 Act on the balance valve, making the balance valve close slowly, when the load pressure P 1 When it is much higher than the back pressure P, the pressure oil may even leak to the oil return line of the system through the balance valve or the winch motor, which cannot effectively improve the heavy objects or the ladder frame sliding caused by the delay of the winch braking, and there are still certain problems. Security risks

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