Patent ID: 7814808
Filing Date: 2010-10-19
Classification: B62D,Y10T

Abstract:
1. A worm gear mechanism, comprising: a driving worm; a torque delivering worm wheel meshing at a first meshing portion of said driving worm for transmitting torque from said driving worm to a load side; an auxiliary worm wheel concentrically superimposed on said torque delivering worm wheel to have a same rotation center line, wherein the auxiliary worm wheel includes a bent portion having a plurality of teeth formed on an outer peripheral surface thereof, the plurality of teeth projecting toward the torque delivering worm wheel, the bent portion being provided only in a region that is radially outward from the same rotation center line of the torque delivering worm wheel so that the plurality of teeth surround an outer peripheral end surface of the torque delivering worm wheel, wherein the plurality of teeth meshes at a second meshing portion of said driving worm, wherein the second meshing portion is provided not to be in a plane extending from the first meshing portion in a direction of a tooth width of said torque delivering worm wheel, the second meshing portion is provided only in a region that is radially outward from the same rotation center line and distanced from the first meshing portion, said auxiliary worm wheel having a pitch diameter greater than that of said torque delivering worm wheel; and a biasing member that normally biases said auxiliary worm wheel against said driving worm in an axial direction.