Design And Test On Delta Tracks Chassis Of Chopper Sugarcane Harvester

Sugarcane is a kind of main economic crop in southern China.It is also the raw material for sugar production.Sugarcane area in China ranked the No.3 in the world,and its sucrose output was about 6.28% of the world's.However,the technology of sugarcane mechanized harvesting was still relatively backward in China.The ratio of mechanized harvesting of sugarcane was less than 1%.It resulted in low efficiency and high cost of sugarcane production in China.More than 60% of the sugarcane field in Guangxi and Yunnan was in hilly and mountainous regions.However,the existing harvesters were unadapted for hilly and mountainous grounds.They were mainly characterized by low efficiency when moving on slope field,poor steering flexibility,and low stability of the machine.Rolling field could also cause the harvester turned over.So,it was of big practical significance to develop a sugarcane harvester which adapted to hilly and mountainous field.In view of the poor adaptability of existing sugarcane harvesters to hilly fields,this paper designed a kind of delta tracks for sugarcane harvester.Finite element static stress analysis and dynamic tests were performed on the main parts of the designed chassis.The comparisons and verifications between theoretical analysis on and test results of the designed steering system were carried out.The main contents and conclusions of research in the paper were as follows:(1)Overall design of the delta tracks chassis was conducted.It included walking device which consisted of delta tracks and normal tracks,and mechanical steering system.(2)Based on the analysis on the ground-to-track force,calculation analysis on trafficability,running resistance,turning radius,and driving stability of the harvester were conducted.The ground specific pressur of the harvester was 82.94 MPa,which was in line with that of most tracked vehicles.The resistance when climbing a 25°slope was 88.06 kN,the power of the machine met its needs of climbing the slope.The minimum turning radius of the harvester was 6.4 m.Both lateral and longitudinal stability on a 25 ° slope Met given standard.(3)Design on the front and rear normal tracks assembly and its key component were conducted.The front delta track frame coule swing around its connecting pin axis on driving wheel mounting frame,and the rear normal track coule swing around its connectingaxle on the wheel bridge connecting frame to adapt to the change of slope on the ground.The rear axle could swing around its connection axis with the frame in cross-section,when the left and right tracks were at different heights level of the ground.That could reduce the lateral roll of the machine and improve its adaptability to the ground and driving stability.(4)Calculation analysis on the strength and stiffness of the key parts of the chassis were conducted with FEA software ANSYS.According to the stress map and deformation map,the rationality and deficiencies of the design were analyzed,The results could provide guidance and reference for improving redesign.(5)Dynamic stress test of key parts of chassis were conducted.The dynamic stress of key parts were tested.The results showed that the stress concentration occured at the welded joint between the inner plate and the horizontal plate of the tracked driving wheel mounting bracket.The maximum static stress was 175.73 MPa.Its dynamic safety factor was 1.36,which was less than the normal value of engineering safety factor of 1.5-2.0.The design needed to be improved.The safety factors of the hollow base frame,the roller bearing mounting frame,the rear drive wheel mounting bracket and the rear axle were all2.0-plus,which met the strength requirements.The dynamic stress of the wheel-bridge connecting frame was 254.97 MPa when steering,and its safety factor was only 1.08.The safety factor was not large enough,the design on connecting frame should be improved later.(6)The turning radius of the prototype were tested.Results showed that the vehicle speed had a certain influence on the turning radius.The minimum turning radius was 6.13 m and 6.56 m when moving in low and high gear respectively.they were close to the theoretically calculated number 6.40 m.Harvesting test of the sugarcane harvester with delta tracks was carried out in field.Its adaptability to the change of terrain slope was obviously better than that of the existing tracked sugarcane harvester.It's the first time for the combination of a delta tracks and a normal track to be applied to a sugarcane harvester.It was innovative design of this paper.