| Loader is one of the most representative products in China's construction machinery industry,and it has been widely used in the field of Engineering construction.It is mainly used for loading and unloading bulk materials,cleaning sites and short distance handling.At present,hydrodynamic drive loaders are mostly used in the industry.hydrodynamic transmission loader can start smoothly,shift smoothly,operate conveniently and have automatic adaptability,but its transmission efficiency is low.When the loader starts to reach a certain speed,the pump wheel and turbine can be connected into one body by installing a locking device in the hydrodynamic torque converter,thus the transmission state can be changed into mechanical transmission,and the transmission efficiency can be significantly improved.Referring to the investigation of foreign related institutions,it is known that under the same conditions,the application of hydraulic torque converter locking control on loaders can effectively reduce fuel consumption by about 10%.Therefore,the study of hydrodynamic torque converter locking is very urgent and important for energy saving of hydrodynamic transmission system of loader.Based on the project of "Construction of Green Design Platform for High-end Earthwork Machinery " of Ministry of Industry and Information Technology of Guangxi Liugong Machinery Co.,Ltd.,this paper designs the structure of hydrodynamic torque converter with locking clutch for 7-ton loader,establish the dynamics of hydrodynamic torque converter model,which is an important transmission component,and simulates and analyses the dynamic process of hydrodynamic torque converter locking by using MATLAB software,and the results are compared with the experimental results.The main work and conclusions of this paper are as follows.(1)The working characteristics of the engine and the hydrodynamic torque converter are analyzed,and then the matching analysis of the two working characteristics is carried out.The input and output characteristic curves of the two working together are drawn as the basis for determining the locking point of the hydrodynamic torque converter in the following paper.(2)The dynamic process of lock-up of hydrodynamic torque converter,the conditions of lock-up and the change law of oil pressure of lock-up clutch are analyzed.According to the method of locking point selection,combined with the comparative analysis of the common output results of engine and hydrodynamic torque converter matching,the suitable locking point is finally selected.(3)The locking hydraulic system of YJ380 hydrodynamic torque converter locking clutch is designed.According to the conditions that the locking process of hydraulic torque converter needs to meet,the changing law of locking oil pressure is designed,and the dynamic process of locking is analyzed.The dynamic model of the locking clutch is established,and the moment of inertia is calculated.The simulation analysis model of the locking process of the locking clutch is established with the help of MATLAB/Simulink software.The variation curves of speed,torque,sliding work and sliding power during the locking process are obtained by simulation.The viewpoint of power diversion during the lock-up process of hydrodynamic torque converter is put forward.The relationship and variation rule between engine power,torque converter transfer power,hydrodynamic loss power,lock clutch transfer power and sliding wear loss power are analyzed.(4)The hydrodynamic torque converter with locking clutch designed in this paper is installed in a 7-ton loader to carry out the whole machine experiment.The input and output rotational speeds of the locked clutch are processed and compared with the simulation results.The possible causes of the errors are analyzed based on the comparison results.The error of simulation and experiment is less than 10% when comparing the speed after locking,which verifies the accuracy of theoretical analysis and simulation results. |
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