Design And Experiments Of The Rape Disc-cutter

The rape, which is one of the main oil crops in our country, is planted in large area. However, the degree of maturity of the rape is not consistent and rapeseeds are easy to loss during mature period. Those are the reason of large mechanical harvesting losses, among which cutting loss has a large proportion. In order to find a new way that could reduce losses of the header on rape combine harvester, the eccentric circular curve disc-cutter with serrations is designed to suit for rape harvest so as to decrease the cutting loss rate and increase economic efficiency of the rape planting. According to the previous study results, to start with the study of rape stalk, writer designed cutter structure, and determined structural parameters; It was obtained that relational expressions of the parameters match could avoid miss cutting and multi-blade cutting through theoretical analysis of the cutter; Contrast test, single factor test and the orthogonal test of four factors at three different levels were conducted on self-made cutting test device; Writer analyzed the results affected by factors and evaluated the cutter working performance based on test results. Conclusions as follows:(1) The diameter of rape stalk that bellows500mm decreases linearly with the height. The main reasons caused losses are cutting bending-destroy and transient vibration of the impulse excitation. The study of mechanical characteristics of rape stalk shows that the impact resistance of rape stalk gets smaller before it gets stale.(2) The eccentric circular curve disc-cutter with serrations satisfies the formula of blade height, the formula of blade number, the formula of cutting velocity and other conditions. When it is grip-cutting, the sliding cutting angle on blade gradually increases with low vibration and stable-cut effect.(3) It is well-matched between the structural parameter and motion parameter that disc-cutter could avoid miss cutting, multi-blade cutting and other problems caused heavy losses. The sliding cutting angle on blade varies from35degree to55degree. It is obtained that the blade tip and the edge of cutter dish are the weakest part during cutting process through the finite element static analysis.(4) Self-made cutting test apparatus satisfies the control requirements of experimental factors, including cutting velocity, cutting height, cutting dip and other requirements.(5) The results of cutting experiments showed that the optimal set of rape cutting parameters, namely the rotating speed equals to750r/min, the cutting height is250mm, the cutting dip equals to10degree, the forward velocity of apparatus equals to0.4m/s, and6cutting blades, consumed power in low and had low loss. The optimizing cutting parameters were obtained through regression optimization, namely the rotating speed equals to700r/min, the cutting height is350mm, the cutting dip equals to5degree, the forward velocity of apparatus equals to0.4m/s, and6cutting blades.(6) Single-factor experiments, multi-factor experiments and regression optimization are well-matched, then it can be proved that experiments have highly reliablility through comprehensive comparison. Experiments are supported by theory, theoretical analysis accords with experimental reality.