Research And Development Of The Closed Hydrostatic Transmission System Of The Combine Harvester

Closed hydrostatic transmission system is gradually used in the walking system of agricultural harvesting machinery because of its smooth power transmission,high efficiency and compact structure,which can realize stepless speed change.When the combine harvester works in the field,the working environment is poor,the unevenness of the road surface has a great influence on the vehicle power transmission system,and the randomness of the dynamic load has a great impact on the operation of walking.The static hydraulic transmission can effectively avoid the impact of dynamic load,realize the smooth work of the whole vehicle and improve the working efficiency of the harvester.This paper mainly determines the scheme of closed hydrostatic transmission system of combine harvester,optimizes and matches the parameters of each component reasonably and chooses the type.The main contents of the research are as follows: designing closed hydrostatic transmission system suitable for combine harvester and establishing stepless speed regulation scheme of pump-controlled motor;analyze the drive scheme of hydraulic system,establish the four-wheel drive scheme of front-wheel main drive and rear-wheel auxiliary drive;analyze the static and dynamic characteristics of pump and motor,point out the factors affecting the characteristics of hydraulic system;analyze the dynamic characteristics of the whole machine;Matching the appropriate hydraulic components;Fitting the field working road spectrum with Matlab software,combining with Adams to simulate the dynamic performance of the whole machine during walking process,get the load curve of the combine harvester in the process of field operation and turning obstacle surmounting;Finally,based on AMESIM software,four working conditions of hydraulic system are simulated and analyzed,including start,field operation,obstacle crossing and four-wheel drive.Through the analysis of theoretical calculation and simulation results,the closed hydrostatic transmission system of combine harvester is reasonable and feasible.