CAJ | 학술논문

为解决中国水田地块小、履带式水稻联合收获机在地头转向所耗时间占作业时间比例大、转弯所占地头长度远比旱田作业长的问题.该文对一种新型机械式单边驱动原地转向机构进行了分析与试验,旨在取代传统转向机构,提高机器作业效率.分析了系统的工作原理,进行了动力学仿真,并做了大量试验.结果显示,该系统可实现原地转向,使转向半径接近或等于零,极大地缩短了转向时间,同时得到不同地面条件、不同转向半径时的转向阻力矩,为后期研究奠定基础.
위해결중국수전지괴소、리대식수도연합수획궤재지두전향소모시간점작업시간비례대、전만소점지두장도원비한전작업장적문제.해문대일충신형궤계식단변구동원지전향궤구진행료분석여시험,지재취대전통전향궤구,제고궤기작업효솔.분석료계통적공작원리,진행료동역학방진,병주료대량시험.결과현시,해계통가실현원지전향,사전향반경접근혹등우령,겁대지축단료전향시간,동시득도불동지면조건、불동전향반경시적전향조력구,위후기연구전정기출.
Combine harvester is one of important tools for rice harvest. Combine harvester is apt to work in the field of high moisture other than wheeled vehicle. So for the sake of steady running, rubber tracked vehicles are commonly applied in harvesters against the characteristics of high moisture and low carrying capacity of paddy soil. Because the combine harvester has large touching surface with soil, the pressure between the earth and track will decline enormously compared with the wheeled vehicle, which can’t work steady due to the sinkage of its wheels. But the long track will cause big turning resistance. In China, the unilateral shift is broadly applied in the medium or small-size tracked vehicles. But this steering ways will often bring accumulation of soil, especially during turning angle with 90?, which will cause hard turning, so it has to turn a little degree each time, and repeat some times to achieve turning. In order to overcome this problem, a new kind of combine harvester steering mechanism was developed in the paper, which contains a pivot turn steering mechanism powered by one-side tractive force using a tracked vehicle chassis attached to the stripping harvester. This machine can realize spin turning at any radius, so it is more flexible in paddy field. In order to obtain the turning resistance parameters and test the turning performance under different working conditions, the straight-line driving and pivot turning experiments were carried out under three different working conditions— solid, hard and paddy fields. The compactness and moisture of the fields were measured. The output shaft torque under each working condition was obtained through the strain test method. The results showed that:1) The driving wheel torque remained the same in the same kind of ground condition no matter straight forward or backward, which indicated no difference between the front or rear wheel driving. 2) The driving wheel torque was relatively small in straight forward or backward under different ground conditions. The torque shoot up under pivot turning especially in the paddy field, which indicated that the friction resistance and side bulldozing resistance between track and the ground increased sharply under pivot turning condition. The driving wheel torque of a pivot turning was 4.5 times of a straight driving under solid or hard ground conditions. But the driving wheel torque of a pivot turning was up to 6 times of a straight forward driving in paddy field. Besides, detailed tests were carried out in paddy field after rice harvest. The left and right output shaft torque in counterclockwise turning, the velocity in straight-line driving and the angular velocity in turning were measured. The results showed that: 1) Left and right output shaft torque increased with the decrease of turning radius. 2) Maximum output shaft torque appeared in pivot turning (the turning radius was 0). In the meantime, the left and right output shaft torques were roughly equal, which were about 2 278 N·m on average. 3) The turning resistance for spin turning was not less than that of the expected pivot turning, but it was dramatically larger at the 0-radius turning. However, the operation of pivot turning was flexible, the angular velocity was approximately 0.619 rad/s, i.e. a 360°turning only need 10 s. Generally just 90 °turning needed in practical working, so the turnaround time was short, which can effectively improve the work efficiency and need less turning area. 4) The regression equation was obtained between the right and left output shaft torque and the turning radius based on the data, which can serve as the empirical formula to predict the left and right output shaft torque under different turning radius. Theoretical analysis and test results prove that the turning mechanism has the characteristics of short turnaround time, less turning area, and so on, which can improve the overall efficiency of the crawler combine harvester. The empirical formula and the turning resistance torque parameters obtained under different ground conditions and different turning radius can lay a foundation for the later study.