Reducer and electric power steering apparatus having the same

摘要

Disclosed are a reducer and an electric power steering apparatus having the same. According to the present invention, an input shaft, a driving shaft, and a pinion shaft are coaxially arranged. Thus, a conventional configuration, in which a motor inevitably protrudes, can be improved to prevent the motor from interfering with the other structures. Therefore, a layout configuration in an apparatus can be compactly formed.

主权项

1. A reducer comprising:
an eccentric cam formed with a coupling hole in which one end of a hollow motor shaft of a motor is fitted; a step gear including a large-diameter portion formed with first gear teeth on an outer circumferential surface of the step gear, the eccentric cam being fitted in the large-diameter portion, and a small-diameter portion extending axially from the large-diameter portion and formed with second gear teeth on an outer circumferential surface of the small-diameter portion, the step gear having a central axis spaced apart from a central axis of the motor shaft by a predetermined distance; a fixed ring gear fixedly supported on a lower inner circumferential surface of a housing of the motor, the fixed ring gear being formed with third gear teeth around an inner circumferential surface of the fixed ring gear to be tooth-engaged with the first gear teeth of the large-diameter portion and being provided to be coaxial to the central axis of the motor shaft; and a movable ring gear being formed with fourth gear teeth around an inner circumferential surface at one side of the movable ring gear to be tooth-engaged with the second gear teeth of the small-diameter portion, wherein a terminal end of a driving shaft, which extends through the eccentric cam from the driving shaft that penetrates the motor shaft and is connected with a steering wheel, is coupled to a central portion of the movable ring gear, and a pinion shaft is coupled to the movable ring gear on an opposite side of the movable ring gear.