Patent ID: 7581618
Filing Date: 2009-09-01
Classification: B62D

Abstract:
1. A transmission ratio variable steering device for transmitting the steering force acting on a steering wheel to steerable wheels through a steering mechanism, the device comprising a housing attached to a steering column; a steering wheel shaft rotatably supported in the housing and connected to the steering wheel side, wherein the steering wheel shaft is supported by the housing through a double row bearing; an output shaft rotatably supported in the housing on the same axis as the steering wheel shaft and connected to the steering mechanism side, wherein the output shaft is supported by the housing through a single row bearing and has an end portion thereof fitted and supported in an end portion of the steering wheel shaft to be relatively rotatable; a planetary gear mechanism composed of first and second sun gears formed at facing end portions of the steering wheel shaft and the output shaft and different slightly in the number of gear teeth, a carrier supported rotatably about a center axis for the steering wheel shaft and the output shaft, and first and second planetary gears supported on the carrier and meshing respectively with the first and second sun gears; a worm wheel rotatably supported on any one of the steering wheel shaft and the output shaft and rotationally engaged with the carrier; a worm shaft meshing with the worm wheel; and a motor mounted on the housing in a direction perpendicular to the rotational axis of the steering wheel shaft and the output shaft and connected to the worm shaft.