Patent ID: 6736235
Filing Date: 2004-05-18
Classification: B62D,F16D,F16H,Y10T

Abstract:
A ball screw mechanism for an electrically powered steering device, which comprises:a ball screw shaft; a rotary nut having an inner peripheral surface formed with an internally threaded helical groove cooperating with the ball screw shaft to define a ball rolling guideway between the ball screw shaft and the internally threaded helical groove; a series of balls disposed in the ball rolling guideway for transmitting a force between the rotary nut and the ball screw shaft; and a plurality of bridge members secured to the rotary nut, to thereby complete the rotary nut, each having a connecting groove segment defined therein for communicating neighboring convolutions of the internally threaded helical groove in the rotary nut; wherein the convolution of the internally threaded helical groove has a non-circulating portion delimited between the neighboring bridge members, wherein no ball of the series of balls moves in the non-circulating portion, and wherein a filler member is disposed in the non-circulating portion to fill up such non-circulating portion.