APPARATUS FOR USE IN TURNING STEERABLE VEHICLE WHEELS

• US 20130240287A1
• Filed: 12/07/2011
• Published: 09/19/2013
• Est. Priority Date: 12/07/2010
• Status: Active Grant

• Current Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Williams, Daniel E., Owens, Elbert
• Granted Patent: US 9,102,354 B2
• Time in Patent Office: Days
• US Class Current: 180/422
• CPC Class Codes: B62D 5/00 Power-assisted or power-driven steering for non-deflectable wheels B62D11/00; fluid-pressure servomotors in general F15B
• CPC Class Codes: B62D 5/06 fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
• CPC Class Codes: B62D 5/087 Sliding spool valves
• CPC Class Codes: B62D 5/09 characterised by means for actuating valves
• CPC Class Codes: B62D 5/12 Piston and cylinder
• CPC Class Codes: B62D 5/22 for rack-and-pinion type
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

An apparatus (10) for use in turning steerable vehicle wheels (14, 16) includes a steering member (12) which is linearly movable relative to the vehicle to effect turning movement of the steerable vehicle wheels. A pinion (28) is disposed in meshing engagement with a rack portion (30) of the steering member (12). A steering column (22) is connected with the pinion (28) and with a vehicle steering wheel (20) such that rotation of the steering wheel results in linear movement of the steering member. An electrically powered steering unit (40) is connected to the steering member (12) for providing steering feel to the operator. A hydraulic power steering motor (60) mechanically connected to the steering member provides steering assist to the steerable wheels (14, 16).

Claims

1. An apparatus for use in turning steerable vehicle wheels, the apparatus comprising:

a steering member which is linearly movable relative to the vehicle to effect turning movement of the steerable vehicle wheels;

a pinion disposed in meshing engagement with a rack portion of the steering member;

a steering column connected with the pinion and with a vehicle steering wheel such that rotation of the steering wheel results in linear movement of the steering member;

an electrically powered steering unit connected to the steering member for providing steering feel to the operator; and

a hydraulic power steering motor mechanically connected to the steering member to provide steering assist to the steerable wheels.

2. The apparatus recited in claim 1 further comprising a controller and at least one vehicle condition sensor for sensing a vehicle condition, the controller receiving an electrical signal from the at least one vehicle condition sensor and operating the electrically powered steering unit in response to the sensed vehicle condition.

3. The apparatus recited in claim 2, wherein the at least one vehicle condition sensor comprises at least one of a steering wheel rotation sensor and a vehicle speed sensor.

4. The apparatus recited in claim 1 further comprising a pump for supplying hydraulic fluid to the hydraulic power steering motor.

5. The apparatus recited in claim 1 further including a valve for directing hydraulic fluid to and from the hydraulic power steering motor for providing steering assist to the steerable wheels.

6. The apparatus recited in claim 5, wherein the valve is a linear valve including a spool that moves axially in response to linear movement of the steering member in order to direct hydraulic fluid to the hydraulic power steering motor.

7. The apparatus recited in claim 5, wherein the valve is mechanically coupled to the steering member, the valve being biased into a first position in which hydraulic fluid is directed to the hydraulic power steering motor without actuating the hydraulic power steering motor, the valve being movable by the steering member into a second position in which hydraulic fluid is directed to the hydraulic power steering motor to actuate the hydraulic power steering motor.

8. The apparatus recited in claim 1, wherein the electrically powered steering unit is mechanically coupled to the steering member.

9. The apparatus recited in claim 1, wherein the electrically powered steering unit applies an axial force to the steering member in order to resist rotation of the steering wheel.

10. The apparatus recited in claim 1, wherein the electrically powered steering unit includes a motor and a drive belt connected to the steering member for applying an axial force to the steering member.

11. An apparatus for use in turning steerable vehicle wheels, the apparatus comprising:

a steering member which is linearly movable relative to the vehicle to effect turning movement of the steerable vehicle wheels;

a pinion disposed in meshing engagement with a rack portion of the steering member;

a steering column connected with the pinion and with a vehicle steering wheel such that rotation of the steering wheel results in linear movement of the steering member;