Closed rotary control system and crane

Abstract

The invention discloses a closed rotary control system and a crane. Stable starting and stopping of the rotary system are achieved through a dynamic buffer control valve and a dynamic brake. Accordingto the percentage of the loading moment, the rotary maximum speed is controlled, meanwhile, the rotary speed still linearly changes in the later stroke of a control handle, and controllability in thespeed limiting speed is improved. The current of a pump displacement swing angel control valve is compensated according to the handle angle change rate, the engine rotating speed or the current of the pump displacement swing angel control valve is compensated according to the change rate of an accelerator pedal, and the control process is stably controlled. Free sliding and rotating speed compensation is carried out on the length of a telescopic arm, and stable control of free sliding and rotating is achieved. The heavy load and high speed work conditions compensate the change response process of the rotary speed, and stable speed changing is achieved. The pump displacement swing angle is monitored, safety control is achieved, and the situation that after the handle returns, the pump displacement swing angle does not return to zero, the dynamic brake is damaged, or the system is in a high-pressure overflow state is avoided.

Description

technical field [0001] The invention belongs to the technical field of construction machinery, in particular to a closed rotary control system and a crane. Background technique [0002] The main functions of the crane mainly include hoisting, telescopic, luffing and slewing, and hoisting and slewing are the two most frequently used actions of the crane in practice. Due to the large inertia of the crane, especially when the heavy-duty slewing starts and stops, it is easy to cause impact problems. Therefore, the slewing action not only affects the stability of the crane, but also has a great impact on the safety of the crane. Users usually require the slewing speed to match the current load situation, good micro-movement, smooth slewing acceleration and deceleration, and no impact during free sliding. Therefore, it is necessary Appropriate control loops and appropriate control strategies are used to achieve stable control of the slewing process. [0003] At present, the crane...

AI Technical Summary

Problems solved by technology

[0007] (1) For a closed system, if the relief valve is used for buffering, it is easy to cause the oil temperature to rise rapidly and reduce the system efficiency;

[0008] (2) Free sliding is achieved by means of on-off valves or speed regulating valves, without considering the speed process limitations of different working conditions (such as different outrigger lengths), and the free sliding process is easy to shake;

[0009] (3) Limiting the maximum rotation speed only according to the current working conditions cannot solve the vibration problem during the acceleration and deceleration of the rotation; at the same time, only limiting the maximum speed according to the working conditions will cause the control range of the handle to decrease, and the angle of the second half of the handle will appear If the speed changes but the speed remains the same, the user experience is poor; or the compensation control interval is mapped from the original control interval, and the calculation amount is large;

[0010] (4) The slewing speed is controlled based on the slewing acceleration, the rate of change of the slewing speed or the rate of change of the engine speed, without compensation from the operator's control process, because of the inertia of different loads, the stability control is performed when the jitter has already occurred, and the stability is poor;

[0011] (5) It does not consider the stable control and response of the slewing under different load conditions (such as heavy load start-up or high-speed slewing speed reduction)

[0012] (6) When the rotary handle returns to the position, the variable pump displacement swing angle is not monitored. If the handle has been returned, but the pump displacement swing angle does not return to the zero range, it may easily cause safety problems

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