Trw Limited

Michael J Boyer

Mark J Bugosh

Don Blandino

Erland K Persson

Michael J Medora

A steering assembly (10) for turning steerable wheels of a vehicle in response to rotation of a steering wheel (12) includes a pinion (30). A steering member (14) is movable axially to effect turning movement of the steerable wheels of the vehicle. The steering member (14) has a rack portion (34) for engagement with the pinion (30) and an externally threaded screw portion (38). A ball nut (140) extends around the screw portion (38) of the steering member (14) and has an internal thread (144). A plurality of balls (200) are disposed between the internal thread (144) on the ball nut (140) and an external thread (40) on the steering member (14) for transmitting force between the ball nut and the screw portion (38) of the steering member. An electric motor (50) includes a rotor (132) drivingly connected to the ball nut (140) and a stator (70). The stator (70) when energized effects rotation of the rotor (132) and, thereby, rotation of the ball nut (140). The steering assembly includes a one-piece molded plastic member (60) having a first axial portion (62) disposed adjacent to the pinion (30), a second axial portion (66) encapsulating and supporting the stator core (72) and the stator windings (82), and a third axial portion (110) supporting the ball nut (140) for rotation with the rotor (132).

Electric steering system with plastic motor tube

A steering assembly (10) includes a housing (28, 60) and a member (14) which is movable axially in the housing to effect turning movement of steerable wheels of a vehicle. The member (14) has a rack portion (36) for engagement with a pinion (30) and an externally threaded screw portion (40). A ball nut (110) extends around the screw portion (40) of the member (14) and has an internal thread (116). A plurality of balls (200) are disposed between the internal thread (116) on the ball nut (110) and the external thread (40) on the member (14) for transmitting force between the ball nut and the screw portion of the member. An electric motor (50) for rotating the ball nut (110) includes a stator (70) and a rotor (80). A bearing assembly (150) supports the ball nut (110) for rotation relative to the housing, the bearing assembly including a plurality of bearings (152) disposed between first and second races (154, 156). The central radial plane (158) of the bearings (152) intersects the internal thread (116) of the ball nut (110). A first portion of the internal thread (116) on the ball nut (110) is disposed radially inward of the rotor (80) and the stator (70), and a second portion of the internal thread on the ball nut is disposed axially outward of the rotor and the stator.

Electric steering system

An apparatus for sensing the relative rotational position between a stator (28) and a rotor (32) in a variable reluctance motor (26) includes a transmitting ring (40) mounted to the rotor (32) and having a transmitting coil (46) mounted thereon. A receiving ring (42) is mounted to stator (46) and has a receiving coil (56) mounted thereon. The receiving coil includes three conductor patterns (56a, 56b, 56c) having the same shape, each of said conductor patterns being electrically insulated from each other, and each conductor pattern being offset from adjacent conductor patterns by 120 electrical degrees. A drive signal is coupled to the transmitting coil. The apparatus further includes a controller (76) for monitoring the outputs from the receiving coil patterns and for determining the relative rotation between the rotor and the stator from the monitored outputs. The receiving coil patterns are each arranged in a circumferentially varying square wave pattern.

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Lake Orion, MI, United States of America

Michael J Boyer