Patent ID: 8783409
Filing Date: 2014-07-22
Classification: B62D,F16H

Abstract:
1. A rack driven electric power steering apparatus comprising: a rack bar having an outer screw groove on an outer peripheral surface thereof; a ball nut having an inner screw groove corresponding to the outer screw groove of the rack bar on an inner peripheral surface thereof to be coupled to the rack bar by means of balls and having a ball circulating passage axially passing through the ball nut between an inner peripheral surface and an outer peripheral surface thereof; a pair of end caps each having a ball introducing passage, one side of which is communicated with the ball circulating passage and an opposite side of which is communicated with the outer screw groove of the rack bar and the inner screw groove of the ball nut, and coupled to opposite inner ends of the ball nut; and a pair of end cap rings selectively coupled to outer sides of the end caps respectively to prevent separation of the balls, wherein the ball introducing passage of the end cap extends in a fork-shaped curved form from a portion where the ball introducing passage is communicated with the ball circulating passage of the ball nut to a portion where it is communicated with the outer screw groove and the inner screw groove, whereby the balls circulate and are introduced smoothly.