Electric power steering assembly

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 one piece integral ball nut and pulley member operatively connected to said screw portion of said rack portion of said steering member for effecting axial movement of said steering member upon rotation of the vehicle steering wheel, said ball nut and pulley member assembly including a ball nut portion and a pulley portion, said ball nut portion including a generally cylindrical outer surface and a generally cylindrical inner surface, said cylindrical outer surface including an axially extending non-threaded section and an axially extending threaded section, said non-threaded section defining a singular bearing seat surface, and said cylindrical inner surface provided with a screw thread convolution formed thereon.;
• a lone bearing unit disposed on said singular bearing seat surface of said ball nut portion for rotatably supporting said ball nut portion relative to said steering member;
• a threaded fastener disposed on said threaded section of said ball nut portion, said fastener adapted to load said bearing unit;
• and
• an electric motor operatively connected to said ball nut and pulley member by said pulley portion.

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 one piece integral ball nut and pulley member operatively connected to said screw portion of said rack portion of said steering member for effecting axial movement of said steering member upon rotation of the vehicle steering wheel, said ball nut and pulley member assembly including a ball nut portion and a pulley portion, said ball nut portion including a generally cylindrical outer surface and a generally cylindrical inner surface, said cylindrical outer surface including an axially extending non-threaded section and an axially extending threaded section, said non-threaded section defining a singular bearing seat surface, said cylindrical inner surface provided with a screw thread convolution formed thereon, said ball nut portion including a shoulder provided at an end of said non-threaded section, said shoulder being offset relative to an adjacent surface of said pulley member;
• a lone bearing unit disposed on said singular bearing seat surface of said ball nut portion for rotatably supporting said ball nut portion relative to said steering member;
• a threaded fastener disposed on said threaded section of said ball nut portion and adapted to load said bearing unit, said shoulder of said ball nut portion engaging an associated surface of said bearing unit when said bearing unit is loaded;
• and
• an electric motor operatively connected to said ball nut and pulley member by said pulley portion.