Electric power steering assembly

摘要

A rack drive assembly adapted for use in a vehicle electric power steering assembly includes a ball nut assembly operatively connected to a screw portion of a rack portion of a steering member of the power steering assembly for effecting axial movement of the steering member upon rotation of a vehicle steering wheel. According to one embodiment, the ball nut assembly includes a first bearing assembly disposed in the rack housing and carried by a ball nut, the first bearing assembly disposed on a first end of the ball nut adjacent a first side of the pulley; and a second bearing assembly disposed in the rack housing and carried by the ball nut, the second bearing assembly disposed on an opposite second end of the ball nut adjacent a second side of the pulley.

主权项

1. A rack drive assembly adapted for use in a vehicle electric power steering assembly comprising:
a steering member disposed in a rack housing and including a rack portion operatively connected to a vehicle steering wheel and a screw portion; a ball nut assembly operatively connected to the screw portion of the rack portion of the steering member for effecting axial movement of the steering member upon rotation of a vehicle steering wheel, the ball nut assembly including a ball nut having an outer surface; an electric motor operatively connected to the ball nut by a pulley assembly, the pulley assembly including a pulley configured to be carried by the outer surface of the ball nut; a first bearing assembly disposed in the rack housing and carried by the outer surface of the ball nut for rotatably supporting the ball nut assembly relative to the steering member, the first bearing assembly disposed on a first end of the ball nut adjacent a first side of the pulley; and a second bearing assembly disposed in the rack housing and carried by the outer surface of the ball nut for rotatably supporting the ball nut assembly relative to the steering member, the second bearing assembly disposed on an opposite second end of the ball nut adjacent a second side of the pulley, wherein the first and second bearing assemblies each include an outer race, wherein the outer race of the first bearing assembly includes an outer surface which is wholly spaced apart from an adjacent inner axially extending surface of the rack housing by a first clearance distance and the outer race of the second bearing assembly includes an outer surface which is wholly spaced apart from an adjacent inner axially extending surface of the rack housing by a second clearance distance which in use allows the associated first and/or second bearing assembly to tilt to allow for misalignment of the steering member, and wherein the second clearance distance is different from the first clearance distance.