Patent ID: 8448742
Filing Date: 2013-05-28
Classification: B62D,G01L

Abstract:
1. An electric power steering system comprising: a column tube which rotatably supports a steering shaft coupled to a steering member; a tubular sensor housing configured by increasing a diameter of an axially lower portion of the column tube; a torque sensor accommodated in the sensor housing for detecting a steering torque; a speed reduction mechanism which transmits rotation of a steering assist electric motor to the steering shaft; a gear housing which accommodates the speed reduction mechanism; and an upper bearing and a lower bearing disposed on upper and lower sides of the speed reduction mechanism and rotatably supporting the steering shaft; wherein the gear housing includes a tubular lower housing which rotatably supports the steering shaft via the lower bearing, and an upper housing; wherein the upper housing includes an inner tube, an outer tube and an annular connection wall connecting the inner tube and the outer tube; wherein the outer tube is press-fitted to an inner periphery of an upper portion of the lower housing; wherein the inner tube rotatably supports the steering shaft via the upper bearing; wherein the inner tube is press fitted to an inner periphery of an axially lower portion of the sensor housing, whereby the inner tube has a reduced diameter so that an outer ring of the upper bearing is Lightly fitted and supported in the inner tube.