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US 4,694,925 AGranted
Steering apparatus
AssigneeTRW Inc.
InventorMaurice P. Roberts
Life of this patent
Estimating the term…
Abstract
A power steering apparatus includes an electric motor having an output member which is drivingly connected with a planetary gear set. An output member of the planetary gear set rotates a ball nut. A member which is connected with a steering linkage has an external thread convolution which is engaged by the ball nut. Upon rotation of a steering wheel, the electric motor is energized to drive the planetary gear set. The planetary gear set in turn drives the ball nut to move the drive member which is connected with the steering linkage.
Claims12
An apparatus for use in turning steerable vehicle wheels, said apparatus comprising:
- an electric motor having a central axis, said electric motor including a motor output member rotatable about said central axis;
- a planetary gear set drivingly connected with said motor output member;
- a transmission output member coaxial with said central axis of said electric motor and connected with said planetary gear set and rotatable by said planetary gear set upon rotation of said motor output member;
- a ball nut attached to said transmission output member for rotation therewith about said central axis upon rotation of said motor output member;
- an externally threaded member disposed in engagement with and circumscribed by said ball nut and coaxial with said central axis and movable axially by said ball nut upon rotation of said motor output member for effecting turning of the steerable vehicle wheels;
- and
- a manually rotatable drive shaft extending axially through said electric motor and said planetary gear set, said drive shaft having an input end portion drivingly connected with the steering wheel and an output end portion drivingly connected with said transmission output member.
4 more elements
An apparatus comprising:
- an electric motor having a central axis, said electric motor including a motor output member rotatable about said central axis;
- a planetary gear set drivingly connected with said motor output member;
- a transmission output member coaxial with said central axis of said electric motor and connected with said planetary gear set and rotatable by said planetary gear set upon rotation of said motor output member;
- said planetary gear set comprising a sun gear drivingly connected with said motor output member, a ring gear fixed against rotation about its own axis, and planet gears meshing with said sun gear and said ring gear, mounted on said transmission output member and rotatable about their own axes relative to said transmission output member;
- a ball nut drivingly connected with said transmission output member for rotation upon rotation of said motor output member;
- an externally threaded member disposed in engagement with and circumscribed by said ball nut and coaxial with said ball nut and movable axially by said ball nut upon rotation of said motor output member;
- and
- a manually rotatable drive shaft extending axially through said electric motor and said planetary gear set, said drive shaft having an input end portion and an output end portion drivingly connected with said transmission output member.
5 more elements
An apparatus comprising:
- a housing;
- a manually rotatable input member mounted within said housing;
- an electric motor located concentrically of said input member and having a rotary armature;
- a sensor for detecting torque in said input member and for actuating said electric motor;
- a first gear concentric with said input member and driven by said armature;
- at least one planet gear in mating engagement with said first gear;
- a planet carrier drivingly connected with said input member, said planet carrier supporting said planet gear for rotation about the axis thereof and being rotatable about the axis of said input member;
- a ring gear fixed to said housing and meshing with said planet gear;
- ball nut means concentric with said input member and driven by said planet carrier, said ball nut means having a threaded protion with at least one ball therein;
- and
- a linear actuator member located concentrically of said ball nut and including a circumferential recess in the form of a thread for receiving said ball, said thread having a lead angle so that rotation of said ball nut causes axial movement of said actuator member.
8 more elements
Dependencies are inferred from the claim text.