Patent ID: 9061698
Filing Date: 2015-06-23
Classification: B62D,F16H,Y10T

Abstract:
1. A speed reducer, comprising: a worm; a worm wheel that meshes with the worm; and a housing that houses the worm and the worm wheel, wherein the housing has a generally cylindrical portion arranged with a space having a constant width between the generally cylindrical portion and an outer periphery of the worm wheel, only (i) a meshing section where the worm and the worm wheel mesh with each other, and (ii) the space between the outer periphery of the worm wheel and the generally cylindrical portion are filled with grease, the grease in the space is in contact with both a tooth surface of the worm wheel and an inner peripheral face of the generally cylindrical portion, the inner peripheral face facing the worm wheel, in the space, a shortest distance between the worm wheel and the inner peripheral face of the generally cylindrical portion in a radial direction of the worm wheel is less than or equal to 1.6 mm, and a viscosity of the grease at 100° C. and a sheering speed of 100 s