Steering gear

Claim 2

A steering gear for turning steerable wheels of a vehicle in response to a manual input, said steering gear comprising a member movable in opposite directions, said member having first and second portions, said first portion including a rack, a rotatable pinion gear engaging said rack for driving said member, rotary electric motor for applying a force to said second portion of said member in response to the manual input, and means for actuating said electric motor in response to a predetermined amount of torque applied to the steering column of the vehicle.

Claim 3

A steering gear as defined in claim 1 wherein said electric motor has a rotatable armature mounted coaxially of said second portion of said member and encircling said second portion of said member, and a drive connection between said armature and said second portion of said member for converting the rotation of said armature into linear movement of said member.

Claim 4

A steering gear as defined in claim 2 wherein said second portion of said member comprises a screw portion and said drive connection comprises a ball nut encircling said screw portion and drivingly connected to said armature.

Claim 5

A steering gear as defined in claim 3 further including a housing for said armature and bearing means between said housing and said ball nut for supporting said ball nut for rotation relative to said housing and for restraining said ball nut from axial movement relative to said housing.

Claim 6

A steering gear as defined in claim 4 further including a clutch interposed between said armature and said ball nut and which is engaged upon actuation of said armature.

Claim 7

A steering gear as defined in claim 5 wherein said motor comprises permanent magnets creating a magnetic field in which said armature is located,.said armature being offset from the center of said magnetic field and moving axially when current is applied thereto to engage said clutch.

Claim 8

A steering gear for turning steerable wheels of a vehicle in response to turning of the vehicle steering wheel, said steering gear comprising a member movable in opposite directions to effect steering in opposite directions, manual steering means for moving said member in response to manual turning of the steering wheel of the vehicle, said manual steering means comprising a pinion meshing with rack teeth on the member and a drive coupling for rotating said pinion in response to turning of the vehicle steering wheel, said drive coupling including first and second coupling parts, one of said coupling parts being connected to the steering wheel and the other of said coupling parts being connected to the pinion, said coupling parts being relatively rotatable in response to a predetermined amount of torque applied thereto, means responsive to relative rotation of the coupling parts for creating an electrical signal, and a rotary electric motor energized by the electrical signal for applying a force to said member independent of the pinion to effect movement of said member.

Claim 9

A steering gear for turning steerable wheels of a vehicle in response to turning of the vehicle steering wheel, said steering gear comprising a member movable in opposite directions to effect steering in opposite directions, manual steering means for moving said member in response to manual turning of the steering wheel of the vehicle, said manual steering means comprising a pinion meshing with rack teeth on the member and a drive coupling for rotating said pinion in response to turning of the vehicle steering wheel, said drive coupling including first and second coupling parts, one of said coupling parts being connected to the steering wheel and the other of said coupling parts being connected to the pinion, said coupling parts being relatively rotatable in response to a predetermined amount of torque applied thereto, means responsive to relative rotation of the coupling parts for creating an electrical signal, and a rotary electric motor energized by the electrical signal for applying a force to said member independent of the pinion to effect movement of said member.

Claim 10

A steering gear as defined in claim 7 wherein said electric motor encircles said member, and said member moves linearly relative to such motor, and said motor has a rotatable armature and a drive connection is provided between said armature and said member to effect linear movement of said member in response to rotational movement of said armature.

Claim 11

A steering gear as defined in claim 8 wherein said drive connection comprises a ball nut and associated balls and said member has a screw portion cooperating with said ball nut and balls for effecting linear movement of said member in response to rotation of said ball nut, means for causing rotation of said ball nut upon rotation of said armature, a housing for said armature, and bearing means between said housing and said ball nut for supporting said ball nut for rotation relative to said housing and for axially restraining said ball nut from movement relative to said housing.