Limit load adjustment method of all hydraulic bulldozer and apparatus thereof

Abstract

The present invention is limit load regulating method and apparatus for hydraulic bull dozer. The present invention features that by means of connecting the throttle valve sensor, the engine rotation speed sensor, walking motor rotation speed sensor and motor proportion valve to the micro controller (MC), connecting the engine to variable displacement oil pump and MC, the calculation in MC of the difference between practical rotation speed and the set value of the engine and the motor based on the signals from the sensors, the data processing and PID operation, the limit load regulating apparatus regulates the current of the electric proportion valve in the variable displacement oil pump and the current of the electric proportion valve in the motor to maintain the rotation speed of the engine in the constant value. The present invention makes the hydraulic bull dozer operate in optimal rotation speed with less fluctuation in high response speed.

Description

Technical field: [0001] The invention relates to the field of construction machinery, in particular to a method for adjusting the limit load of a full hydraulic bulldozer and a device designed by the method. Background technique: [0002] At present, the TQ230 and TQ230A fully hydraulic bulldozers developed in China adopt a fixed minimum displacement control method for throttle limit load adjustment. When the bulldozer is working, the speed sensor transmits the speed data of the engine at a certain throttle position to the PLC controller, and the PLC controller compares the data with the no-load speed of the engine at the same throttle position (pre-stored in the PLC). The corresponding rotational speed difference is obtained. When the difference exceeds the maximum set value, the PLC controller issues an instruction to input a certain pressure value to the proportional pressure reducing valve controlling the displacement of the variable oil pump, thereby reducing the displ...

AI Technical Summary

Problems solved by technology

This kind of full hydraulic bulldozer has the following defects: ①Because the set minimum displacement value is a fixed value, the load variation range of the bulldozer is large and the load changes drastically, resulting in a large error in the control system, and the system cannot track the change of the load. The engine speed fluctuates in a wide range, up to 800rpm at the maximum, resulting in power loss; ②When the speed difference exceeds the maximum set value, the displacement of the variable pump is reduced to the set minimum displacement, causing the bulldozer to stop while running , the vehicle speed fluctuates greatly, resulting in a decrease in operating efficiency and an increase in the load of the transmission system; ③ Since the control method of the variable pump adopts a hydraulic control method, the control actuator is an electric proportional pressure reducing valve, and its hydraulic control signal is transmitted by an electric proportional pressure reducing valve, a manual Proportional decompression valve (traveling handle), hydraulic control proportional servo valve, variable pump swash plate positioning cylinder, and finally the variable pump swash plate moves

The accumulation of the volume effect of each component will lead to signal lag, which will make the adjustment performance worse, and the machine will appear system vibration or crawler walking stop phenomenon when the machine is working under heavy load; ④ With the increase of use time, the leakage of the pump and motor will increase increase, the output power of the engine will decrease, and the minimum displacement value will not meet the normal operation requirements of the bulldozer

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