| 摘要 |
<p>A planetary reduction gear comprising pairs of partial planetary gears (2a, 2b), two partial internal gears (41a, 41b) and a sun gear (11) or comprising pairs of partial planetary gears (2a, 2b), two partial sun gears (11a, 11b) and an internal gear (41) in which partial planetary gears mesh with partial internal gears or with partial sun gears independently. One of the partial gears is fixed to the input shaft (1) or to the casing. The other partial gear is loosely connected to the input shaft (1) or to the casing by a spiral coupling which allows the partial gear to move in spiral direction. A pressing means (54) urges the partial gear in axial direction. The force of the pressing means moves the partial gear in the spiral direction. The partial gear rotates slightly relatively to the other partial gear. This relative rotation of the partial gears cancels any backlash. In the case of helical gears, the spiral coupling can be replaced by an axial coupling. The loosely coupled partial gear can rotate by a cam device comprising tapered keys and axial notches of the partial gears. Axial displacement of the partial sun gear results in a slight rotation of the partial helical planetary gear equal to any backlash. <IMAGE></p> |
