No abstract

To reduce the inertial force of the oscillating sieve and return pan of a rice combine harvester, partial equilibrium was adopted. Firstly, based on the kinematic analysis of a slider-crank mechanism, the appropriate mass of counterweight intervals was achieved. Then, an ADAMS dynamic simulation was used to determine the optimum balance mass of the oscillating sieve and return pan individually. Considering the relative motion between the return pan and the oscillating sieve, the overall inertial force of the two parts would be reduced. The simulation results indicated that the optimum counterweight of the oscillating sieve was 15.5 kg based on an analysis of the movement tracks of the mass center and overall inertial force. The results also showed that the overall balance of inertial force not only reduced the counterweight but also decreased the overall inertial force of the oscillating sieve and return pan. Finally, a search for the most suitable crank initial angle of the return pan to reduce the overall inertial force and optimize the overall balance revealed three groups of initial angles: φ=0°, φ=45°, and φ=90°. The results indicated that arranging the initial angle of the crank of the oscillating sieve and return pan in the same position (φ=90°) was the most favorable for reducing the overall inertial force. In this situation, the optimum counterweight of the oscillating sieve was only 14.0 kg. The results can provide references for the design of the overall balance of the inertial force in the cleaning components of a combine harvester.

Rapeseed cleaning loss is an important factor to weigh rapeseed combine harvester performance. With the development of sensor technology, establishing a rapeseed cleaning loss monitoring system can be interesting and necessary. However, the rapeseed combine harvester made in China is always with larger vibration, which is not beneficial for sensor monitoring accuracy. Experiment results indicate that inertia force from vibrating sieve unbalanced motion has the greatest influence on the monitoring accuracy of the sensor in its installation position. To reduce the effect of vibration on monitoring accuracy of the sensor, the vibration absorption and isolation structure for cleaning loss sensor has been designed. Moreover, the vibration isolation design was performed on the basis of vibration suppression. The vibration isolation rubber was designed to isolate the vibration at the joint of the sensor with the frame. The experimental results shown that the above design can reduce the vibration disturbance and highlight the grain collision signal greatly, which is beneficial for improving the sensor discrimination ability.