Abstract:
Objective In order to solve the problems that the seed guard belt is easy to deviate and slip in application of the combined type-hole metering device of rice precision hole seeder, which leads to serious wear of the seed guard belt and high rate of seed damage.
Method The synchronization principle of seed protection mechanism was analyzed, and the shaft sleeve structure(A) and the hardness of seed guard belt(B) were optimized. A two-factor experiment with different bushing structures (A1 as nylon bushing structure, A2 as needle bearing & copper bushing structure) and hardness of seed guard belt (B 1, B2, B3, B4 and B5 represented the hardness of 40, 45, 50, 55 and 60 HA, respectively) was designed using rice variety ‘Peizataifeng’ and ‘Xiushui134’ seeds as test materials.
Result The experimental groups of A and B had the highly significant effect on the damage rate of rice seeds (P < 0.01), and there was a significant interaction between A and B ( P < 0.05). A 2B2 and A2B3 had the least effect on seed damage rate. There was a highly significant difference between A1 and A2, and seed damage rate of A2 was significantly lower than that of A1, indicating that A2 was better than A1. There was no significant difference between B2 and B3, but B2 and B3 had significant difference with other groups. The experimental group A had a significant effect on hill diameter, B had no significant effect on hill diameter, and the groups of A2B2, A2B3 and A2B4 had the less effect on hill diameter. There was a significant difference between A1 and A2, and A2 was significantly better than A1.The results of test showed that the wear of seed guard belt of A2B3, A2B4 and A2B5 were less after working for 100 hour. The grouo A2B3 was the optimal with the wearing volume of 72.6×10−3 mm3 and seed injury rate of 0.04%, and the hole forming ability and sowing effect were both the best.
Conclusion The optimized design of needle bearing & copper bushing shaft sleeve structure is reasonable. It can significantly reduce the friction coefficient between sleeve and shaft, is more resistant to high temperature and wear resistance, effectively improves the synchronization of seed guard belt, and significantly improves the reliability and sowing quality of seed platter.