Mechanism And Experimental Study On The Front-load Chopper In Sugarcane Harvester

The mechanization of sugarcane harvest is the inevitable trend of sugarcane production in China based on the benefits of cost reduction and efficiency improvement.The sugarcane chopper is a critical component of sugarcane harvester,and also is one of the most power consumption components.The performance of chopper device is in direct relation to harvest index which is composed by chopping loss and billet quality.At present,the level of mechanization of sugarcane harvest in our country is low,more than that,the correlational research of chopper device is still blank,and existing chopper harvester which adopted structure of rear-load chopper were liable to be blocked when processing bent and lodging cane.In this research,roll-cutting mechanism has been clarified through theoretical analysis,and the affection of structure and work parameters of chopper device about chopping quality and chopping power consumption.Based on the foregoing research,a header of harvester with front-load chopper has been developed,which improving the adaptability to the bent and lodging sugarcane and ensuring the working performance.The main conclusions are as follows:1.Through theoretical analysis,the empirical formula of billet length without gripping and the knife install guidelines had been proposed.Stem substantive separation moment has been obtained creatively,and chopping process was divided into roll cutting and toss process based on this separation moment.Motion and stress of blade and stem hast had been analyzed.The structure parameters were deemed as the key factors to chopping quality,chopping loss was analyzed from roll cutting movement which produced extrusion to end face of billets.Power consumptin in chopping with gripping was divided into roll cutting,tossing and offseting retardation from conveyor roller and divided into posture adjusting,roll cutting,self-feeding and tossing without gripping.2.A three-dimensional dynamic simulation model of "chopper device-sugarcane "had been developed,then simulation experiment was carried out by using of ANSYS/LS-DYNA,and the obtained chopping process was correspond to the theoretical analysis.Multiple parameters simulation had been used to verify that when chopper drum radius was 160 mm,drum rotate speed was 300 r/min,and staggered depth was 6 mm,the axial peak stress on billets was 1.39×107Pa.The influence from above factors on the same peak stress was prominent.3.A chopper test unit was designed and a high speed video camera was used to record chopping process under different operating condition.The forming process of fracture surface which contains flush,step shaped,ripped,squeezed and split and chopping loss which consist of chippings and fragment was obtained.Stem movement type which included upwarp,bounce,rotation and overturn was summerized.On the other hand,the cutting form of leaves was supported cut with leaves attach to stem and unsupported cut with leaves dissociate to stem.The cutting effect of the former was superior to the later,and the end of the leaves got the worst cutting effect.4.In the aspect of chopping quality:the length coefficient ? of the designed chopper ranges from 0.72 to 0.73 without gripping;The billets acceptability generally rises with increasing drum speed,and with the increase of the staggered depth,and the tendency is to increase first and then decrease.Rip and squeezing were the main form of worn fracture,both were decrease first and then increase along with the increase of staggered depth,and squeezing was more sensitive than rip.Split took up a small proportion in worn fracture.When the drum rotate speed was 290 r/min,staggered depth was 6.3 mm,the maximum billets acceptability was 89.6%.Power consumption in chopping process showing the trend of growth with the increase of feed quantity The device got smaller power consumption at the positive phase position of blades.5.Aiming at the blocking problem with bent cane,a harvest process of'overwhelm-base cut-chop-convey" was proposed,and a header with a front-load chopper had been developed.The test results showed that the header got a sound adaptation to bent cane.The length coefficient.?was about 0.7,variable coefficient was 0.19,and the billet acceptability got 89.2%at a forward speed of 2 km/h,the same value was 88.8%at 4 km/h.