| 摘要 |
<p>PURPOSE:To promote the stability of gear engagement by improving the shape of a worm against a cylindrical pinion of the same size to increase the capacity of displacement and increasing the stretch of the contacting part between the pinion teeth and the worm thread. CONSTITUTION:An external-form generating line 61 of the second cone part 6Y especially provided on a worm 6 is almost parallel with a generating line 62 of a thread bottom cone shaped by thread bottoms of the worm 6, and the first cone 6X is shaped from the small end part of the second cone 6Y toward the terminal point of the engagement between a thread and a tooth. In this construction, the cutoff-line of the pinion 7 to close the thread is accorded with the deddendum circle of the pinion 7, and the whole surface of the tooth can be effectively used for closing. As the worm 6 is rotated, the tooth is shifted to the thread of the first cone part 6X to start the reduction of the closing area, and the thread space, that is, the capacity of displacement is increased as illustrated. Besides, the increase of the stretch of the contacting part between the teeth of the pinion 7 and the thread of the worm 6 promotes the stability of engagement between them.</p> |
