Plastic molded gear, and intermittent rotation transmission device and gear train using same

摘要

A plastic molded gear capable of reducing teeth knocking noises due to backlash during engagement. A protruding portion 5 for eliminating backlash is formed so as to protrude from both end portions in facewidth directions on one tooth flank 6 of each tooth 2, and the protruding portion 5 is not formed on the other tooth flank 12 of the tooth 2. If the protruding portion 5 is elastically deformed so as to absorb backlash, the protruding portion 5 has the same plane as that of the one tooth flank 6, and the other tooth flank 12 of the tooth 2 serves as a main power transmission surface. With this construction, the protruding portion 5 elastically contacts the tooth flank of a companion gear engaged with the plastic molded gear, so that the elastic deformation of the protruding portion 5 absorbs rotational energy of the companion gear during intermittent rotation. Thus, when gears engaged with each other collide with each other, it is possible to absorb shocks, so that it is possible to reduce teeth knocking noises.