| 摘要 |
The invention presents a method of manufacturing a multi-pitch screw having desired threads and pitches by rolling. A trace of general (even lead angle) spiral screw is formed by even pitch protrusions 610 and 620 of an existing rotating dies 61 and 62, and it is combined with a trace of stair step screw formed by stair step protrusions 632 of a rotating die 63 of uneven lead angle, and multi-pitch screw threads are formed efficiently. Herein, only one rotating die 61 of uneven lead angle is used, and screw threads are not flattened out by stair step protrusions of the plurality of rotating dies of uneven lead angles.
|
