Electric steering apparatus

• US 6,923,288 B2
• Filed: 03/29/2001
• Issued: 08/02/2005
• Est. Priority Date: 04/03/2000
• Status: Expired due to Term

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Szabela, William A.
• Primary Examiner(s): DePumpo, Daniel G.
• Application Number:
  US10/239,798
• Publication Number:
  US 20040020708A1
• Time in Patent Office: 1,587 Days
• Field of Search: 180/443, 180/446, 180/402, 180/403
• US Class Current: 180/402
• CPC Class Codes: B62D 5/001 Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
• CPC Class Codes: B62D 5/006 power actuated
• CPC Class Codes: B62D 5/092 the electric motor being connected to the final driven element of the steering gear, e.g. rack

Abstract

A steering apparatus (10) for a vehicle having steerable wheels. The apparatus (10) comprises a rotatable vehicle steering wheel (12) and a first assembly (100) operatively coupled to the steering wheel. The first assembly (100) includes a sensor (30) for sensing applied torque and angular position of the steering wheel (12) and a first electronic control unit (50) for generating a first signal corresponding to the sensed torque and angular position of the steering wheel. A second assembly (100) is operatively coupled to the steerable wheels. The second assembly (100) includes a second electronic control unit (110) for receiving the first signal, a first electric motor (120) controlled by the second electronic control unit, and a steering gear (130) which is actuated by the first electric motor (120) to turn the steerable wheels of the vehicle. A signal transmitting conductor (250) transmits the first signal to the second electronic control unit (110).

Claims

1. An apparatus for turning steerable wheels of a vehicle in response to turning of a steering wheel of the vehicle, said apparatus comprising:

a first assembly operatively connected to the steering wheel, said first assembly including a sensor apparatus which senses torque applied to the steering wheel and an angular position of the steering wheel, a first electric motor operatively coupled with the steering wheel to provide resistance to rotation of the steering wheel, and a first electronic control unit connected with said first electric motor, said first electronic control unit is operable to generate a first optical signal which is a function of the sensed torque applied to the steering wheel and the sensed angular position of the steering wheel;

a second assembly operatively coupled to a steering mechanism connected with the steerable wheels of the vehicle, said second assembly including a sensor apparatus which is connected with the steering mechanism and is operable to sense a position of a portion of the steering mechanism connected to the steerable vehicle wheels to thereby sense a position of the steerable vehicle wheels, a second electric motor which is connected with the steering mechanism and is operable to effect operation of the steering mechanism to change the position of the steerable vehicle wheels, and a second electronic control unit connected with said second electric motor, said second electronic control unit is operable to generate a second optical signal which is a function of the sensed position of said portion of the steering mechanism; and

a fiber optic cable connected with said first and second electronic control units, said fiber optic cable is effective to conduct said first optical signal from said first electronic control unit to said second electronic control unit to enable said second electronic control unit to control operation of said second electric motor as a function of the sensed torque applied to the steering wheel and the sensed angular position of the steering wheel, said fiber optic cable is effective to conduct said second optical signal from said second electronic control unit to said first electronic control unit to enable said first electronic control unit to control operation of said first electric motor as a function of the position of said portion of the steering mechanism.

2. An apparatus as set forth in claim 1 wherein said first and second electronic control units have multiplexing capabilities to enable said first electronic control unit to send the first optical signal which is a function of the sensed torque applied to the steering wheel and the sensed angle of rotation of the steering wheel over said fiber optic cable to said second electronic control unit while said second electronic control unit is sending the second optical signal which is a function of the sensed position of said portion of the steering mechanism over said fiber optic cable to said first electronic control unit.

3. An apparatus as set forth in claim 2 wherein said second electric motor is a dual drive electric motor having a rotor with first and second sets of permanent magnets which are rotatable together about an axis of rotation of said second electric motor and a stator which extends around said rotor and includes first and second sets of windings, said first set of windings extends around said first set of permanent magnets and said second set of windings extends around said second set of permanent magnets.

4. An apparatus as set forth in claim 3 wherein said second electronic control unit includes a first motor drive circuit which is operable to direct electrical current to said first set of windings and a second motor drive circuit which is operable to direct electrical current to said second set of windings.

5. An apparatus for turning steerable wheels of a vehicle in response to turning of a steering wheel of the vehicle, said apparatus comprising:

a steering mechanism connected with the steerable vehicle wheels, said steering mechanism includes an axially movable steering member and a ball nut which is rotatable about a longitudinal central axis of said steering member;

a first assembly operatively connected to the steering wheel, said first assembly including a sensor apparatus which senses torque applied to the steering wheel and an angular position of the steering wheel, a first electric motor operatively coupled with the steering wheel to provide resistance to rotation of the steering wheel, and a first electronic control unit connected with said first electric motor, said first electronic control unit is operable to generate a first signal which is a function of the sensed torque applied to the steering wheel and the sensed angular position of the steering wheel;

a second assembly connected with said first assembly and operatively coupled to said steering mechanism, said second assembly including a sensor apparatus which is connected with the steering mechanism and is operable to sense a position of a portion of the steering mechanism connected to the steerable vehicle wheels to thereby sense a position of the steerable vehicle wheels, a second electric motor which is connected with the steering mechanism and is operable to effect operation of the steering mechanism to change the position of the steerable vehicle wheels, and a second electronic control unit connected with said second electric motor, said second electronic control unit is operable to generate a second signal which is a function of the sensed position of said portion of the steering mechanism; and

a signal conductor connected with said first and second electronic control units, said signal conductor is effective to conduct said first signal from said first electronic control unit to said second electronic control unit to enable said second electronic control unit to control operation of said second electric motor as a function of the sensed torque applied to the steering wheel and the sensed angular position of the steering wheel, said signal conductor is effective to conduct said second signal from said second electronic control unit to said first electronic control unit to enable said first electronic control unit to control operation of said first electric motor as a function of the position of said portion of the steering mechanism,

said second electric motor is a dual drive electric motor having a rotor with first and second sets of permanent magnets which are rotatable together about an axis of rotation which extends transverse to a central axis of said steering member and a stator which extends around said rotor and includes a first set of windings which extends around said first set of permanent magnets and a second set of windings which extends around said second set of permanent magnets, said second electronic control unit includes a first motor drive circuit which is operable to direct electrical current to said first set of windings to effect rotation of said rotor about the axis of rotation which extends transverse to the central axis of said steering member and a second motor drive circuit which is operable to direct electrical current to said second set of windings to effect rotation of said rotor about the axis of rotation which extends transverse to the central axis of said steering member.

6. An apparatus as set forth in claim 5 wherein said signal conductor is a fiber optic cable, said first and second electronic control units have multiplexing capabilities to enable said first electronic control unit to send the first signal over said fiber optic cable to said second electronic control unit while said second electronic control unit is sending the second signal over said fiber optic cable to said first electronic control unit.