NEW TYPE OF LIMITED-SLIP DIFFERENTIAL WITH THREE-PITCH FLUCTUATING SPEED RATIO

A type of three-pitch fluctuating speed ratio limited-slip differential （TPLSD） is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth profile and separated tooth profile design along the pitch line. Performance comparison between vehicles equipped with three-pitch fluctuating speed ratio limited-slip differential and common open differefitial is finished. The data from experiments prove that three-pitch fluctuating speed ratio limited-slip differential can increase the traction of a vehicle, improve its acceleration performance, decrease braking distance and limit sideslip. The basic structure of new differential is the same of open differential, the only difference is that they have different tooth profile, so the new differential has a high performance price.

Performance analysis and test of a maize inter-row self-propelled thermal fogger chassis

In view of the difficulties in weeding and plant protection in the middle and late period of maize planting,this paper proposed a self-propelled thermal fogger chassis.According to the theoretical calculation and agronomic requirements for maize planting,the structure and working principles of the self-propelled thermal fogger chassis were introduced.On this basis,the multi-body dynamics model of chassis structure was established,and the chassis traction,steering and obstacle surmounting performances were also analyzed.Then the rationality and the feasibility of the design were verified through the furrow running test and test equipped with thermal fogger.Test results showed that,the traction performance improves with the decrease of soil deformation index and increase of cohesion,and when track pre-tensioning force was about 1000 N,the machine had a good traction performance;with the decrease of the soil deformation index and the increase of cohesive force,the stability of the single side brake turn of the chassis becomes better;on the contrary,with the increase of the tightness of the crawler,the steering radius turns smaller and the steering stability becomes worse.Under heavy clay,with the pre-tensioning of 1000 N,the machine has better steering stability and smaller turning radius.The obstacle-surmounting simulation result shows that on sandy soil road,the maximum climbing angle for the chassis is 42°,the height of vertical obstacle crossing is 170 mm and the trench width is 440 mm.The study provides a reference for the design of plant protection machinery in the middle and late stages of maize planting.

Powertrain parameter matching and optimal design of dual-motor driven electric tractor

The rationality of powertrain parameter design has a significant influence on the traction performance and economic performance of electric tractor.At present,researches on powertrain parameter design mainly focus on electric vehicles,and electric agricultural machinery draw much less attention.Therefore,a method of powertrain parameter matching and optimization design for electric tractor was proposed in this paper,which was based on dual-motor coupling drive mode.The particle swarm optimization(PSO)algorithm based on mixed penalty function was used for parameter optimization.Parameter optimization design was programmed using MATLAB.A simulation dynamic model with optimization design variables of electric tractor powertrain was established based on MATLAB/Simulink.Compared with the simulation results before optimization,the objective functions were optimized and the traction performance of electric tractor was improved,which indicated the effectiveness of the proposed method.