Research On Rotating Compound Action For Medium Backhoe Hydraulic Excavator

The performance of slewing and its compound action in hydraulic excavator operation directly affects the performance of the whole machine.The slewing process is prone to problems such as unstable operation caused by hydraulic shock and uncoordinated action caused by unreasonable flow distribution.In this paper,a medium-sized hydraulic excavator of a domestic brand is taken as the research object,and the characteristics of the slewing system and the composite action of slewing and rising of the movable arm of this model are analyzed and studied.Combining with the actual operating conditions,the factors affecting the slewing and slewing compound action are determined from the smoothness,coordination and energy-saving characteristics of the excavator’s action in view of the performance requirements of the hydraulic excavator slewing compound action.The main factors are the resistance torque of the slewing platform,the relief pressure of the slewing motor and the flow distribution of the slewing and moving arm circuits during the compound action.This paper focuses on how to control the flow distribution of the slewing and moving arm circuit of the excavator.By analyzing the working principle and characteristics of hydraulic excavator,the analysis and calculation of the start-up acceleration,uniform speed and deceleration &braking process of the slewing system,and the flow distribution characteristics of the slewing and movable arm rising compound action were studied.A joint simulation model of the mechanical hydraulic system of the excavator was established by using AMESim simulation software and ADAMS dynamics simulation software.According to the experimental specification of excavator,the motion attitude of excavator was simulated under different working conditions.Then the single action of slewing and the combined action of slewing and moving arm rising were analyzed and compared with the experimental data to verify the correctness of the simulation model.From the simulation analysis,it is concluded that the mismatch between the input flow rate of motor circuit and the required flow rate during motor slewing is one of the main reasons for excessive overflow loss during the excavator slewing start stage and compound action.This paper combines the coordination requirements of slewing angle and movable arm rise height under different operating conditions in actual working conditions,thus proposing to increase the throttle channel of the slewing throttle valve.The scheme detects the driving pressure of the slewing motor to regulate the amount of oil entering the slewing motor,which in turn reduces the amount of oil entering the slewing motor during the slewing start phase of the excavator.The solution prevents excess hydraulic oil from flowing back to the tank through the slewing motor’s slewing relief valve,thus reducing overflow losses,while coordinating the slewing angle and boom rise speed.The solution was verified by simulation experiments.