| 摘要 |
PROBLEM TO BE SOLVED: To provide a Niemann type worm gear having satisfied meshing performance without enhancing machining accuracy. SOLUTION: This worm gear comprises a worm shaft having a tooth profile formed in a recessed arcuate shape and a worm wheel having a tooth profile formed in a projecting arcuate shape corresponding to the recessed arcuate shape and having a radius of curvature within the range of machining for forming the tooth profile is larger than that within the engagement range with the worm shaft. The ratio of the radius of worm wheel having the tooth profile formed in the projecting arcuate shape to the radius of the worm shaft is designated as a first radius ratio, and the ratio of the radius of the having the tooth profile formed in a linear shape to that of the worm shaft is designated as a second radius ratio. Where the relations between the variations of the first and second radius ratios and a variation in the maximum allowable amount of the axial displacement error of the worm shaft are designated as first and second characteristic lines, the first radius ratio is formed in the area where the maximum allowable amount of the axial displacement error is larger than at the intersection of the first and second characteristic lines. COPYRIGHT: (C)2007,JPO&INPIT
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