Reliability Design Of Gearbox Of Root-cutting Machine And Studies On Resistance Measuring System

With the technical development of science, all countries paid more attention to the reliability which had already become the focus of the product competition. Gearbox was the key part of wheat root-cutting machine, and the design results of normal design method- Safe Coefficient Method were not reasonable with lower reliability and higher cost. As modem design method-Reliability Design took the design parameters as random variables, so the results were more reasonable and reliable.1. Finishing the reliability design of key parts in gearbox of wheat rooting-cutting machine by modern design theory.Based on stress-strength interference theory, this article used probability theory to compute the rate of expiration, used mean-variance method to get the distribution of random variables and used linkage equation to finish the design of critical parts of reduction box in root-cutting machine, including shaft, gear, roller chain, V-belt and so on.Design results demonstrated that the cross- section of 4 shafts could be reduced by 32.18%, 26.53%, 13.78% and 21.98% respectively with lower cost and higher reliability of more than 0.999.And the reliability of the system was 0.93997,higher than 0.9.2. Finishing the design of soil resistance measuring system based on single chip microcomputer.To supply the distribution of stress, a soil resistance measuring system based on single chip microcomputer. Hardware including:(l)Controlling part:89C51 and expansion of I/O ports;(2)Signal acquisition and processing: Sensors, AD converting and data storing;(3)Keyboard and data display and other parts. Software molds including displaying, key interrupting, AD converting, data storing and other processing ones.The simulating A/D converting experiments were finished and the results demonstrated that the function was realized and data could be acquired and displayed by designed frequency. By regression statistacale analyses,theresults showed that output was in line with analog voltage signals and the linearity was 0.9667723. The experiments were the preparation for field experiment.