| 摘要 |
PROBLEM TO BE SOLVED: To solve problems wherein although a conventional plastic worm has no thin-wall part to prevent direct effects on performance, a complicated three-dimensional curved surface of a parting line of a die makes it difficult to manufacture the die, increases the manufacturing cost and elongates the manufacturing cycle, and when large quantity of worms are manufactured, wear occurs on the mating surface of the die parting line and this worn surface generates projections and burrs on tooth flanks of the worms, affecting noise of a drive unit or a reduction gear. SOLUTION: This worm has a structure formed by combining a basic worm part formed by cutting a normal worm on an approximately vertical plane and a flat plate part stretched and formed to have predetermined thickness preventing thinning in the axial direction by using the shape of the cut face as a boundary, and a simple flat parting line is used as a die parting line. Thus, this eliminates not only a thin-wall part but also a complicated three-dimensional curved surface, so as to facilitate die processing and prevent effects on a device caused by wear even when a large quantity of worms are manufactured. COPYRIGHT: (C)2009,JPO&INPIT
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