Design of eccentric modified gear

Due to its simple design and convenient processing, eccentric circular gear is widely used in the transmission system of non-uniform motion. Compared with elliptical and non-circular gear transmission, the backlash of eccentric gear changes periodically in the transmission and will cause vibration and rotational speed runout under the condition of high-speed operation. Therefore, it is generally used in inaccurate non-uniform transmission. Chen Yiqun et al. Did not study the change of backlash in eccentric gear transmission, but obtained an approximate trajectory. Guo LS pointed out that the pitch curves of the two gears are not always tangent in the meshing transmission process of the eccentric gear and can not be regarded as pure rolling. Zhao Yun and others proved three important properties of eccentric gear planetary transmission, and applied modern design theories and methods to optimize the core working parts of rice transplanter. Eccentric gear planetary transplanting mechanism is one of the earliest models successfully applied to the transplanting mechanism of high-speed rice transplanter in Japan, and has been used until now. In order to eliminate the backlash, superimposed double piece gear and volute spring are adopted.

(1) the method of non-zero unequal displacement of eccentric gear according to the variation law of backlash is feasible; The eccentric modified gear generated by non-zero unequal displacement method can eliminate the backlash and realize the meshing without backlash.

(2) the displacement amount depends on the meshing tooth side clearance, the tooth side clearance depends on the center distance variation coefficient, and the center distance variation coefficient depends on the position of the gear pitch curve. Therefore, the amount of displacement depends on the position of the gear pitch curve.

(3) the test report of the inclined wide and narrow row rice transplanter equipped with eccentric displacement gear transplanting mechanism shows that the operation quality is good and the test performance index meets the national standard.

An eccentric modification gear transmission mechanism for eliminating backlash is designed: one eccentric gear in a pair of eccentric gears makes the pitch curve always tangent to the other eccentric gear through gear modification, so as to ensure that the backlash remains unchanged during gear meshing, and the mechanism is theoretically analyzed and field tested.

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