Front Steering Module For A Zero Turn Radius Vehicle

• US 20080277188A1
• Filed: 07/24/2008
• Published: 11/13/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Hydro-Gear Limited Partnership
• Original Assignee: Hydro-Gear Limited Partnership
• Inventors: Hauser, Raymond, Bell, Douglas W., Steenburg, Bryce E., Bennett, Michael L.
• Granted Patent: US 8,950,520 B2
• Time in Patent Office: Days
• US Class Current: 180/422
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/04 by means of separate power sources
• CPC Class Codes: B62D 3/02 mechanical
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 5/046 Controlling the motor
• 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
• CPC Class Codes: B62D 7/12 with twin-output steering gear

Abstract

A front steering module adapted for integration with the subframe of a zero-turn radius vehicle incorporating an electronic steering apparatus. The module provides both front wheel steering and corresponding control inputs for the electronic steering apparatus. The module has a frame member having a pair of steered wheel assemblies mounted thereto and a mounting member for attachment to the vehicle. The module further comprises a steering mechanism and a steering position sensor for providing input to the electronic steering apparatus.

Claims

1. A modular front steering assembly adapted for attachment to a subframe and electronic drive control system of a vehicle capable of zero-radius turn operation or near zero-radius turn operation, the assembly comprising:

a frame member having opposed ends;

a mounting member affixed to the frame member, wherein the mounting member is adapted for attachment to the vehicle subframe;

a pair of wheel assemblies each attached proximate to one of the opposed ends of the frame member, each wheel assembly pivotable about a vertical steering axis;

a steering mechanism operatively connected to the pair of wheel assemblies, the steering mechanism supported by the frame member and having a steering input device, wherein the steering mechanism induces a progressive Ackerman effect in the pair of wheel assemblies as the steering input device is moved away from a center position; and

a steering position sensor mounted to the steering mechanism for sensing movement of the steering mechanism and capable of being communicatively connected with the electronic drive control system of the vehicle, wherein the steering position sensor emits a signal proportional to the movement of the steering mechanism.

2. The modular front steering assembly of claim 1 further comprising a wiring harness connected to and extending from the steering position sensor.

3. The modular front steering assembly of claim 1 wherein the steering input device comprises a steering wheel attached to a rotatable steering column.

4. The modular front steering assembly of claim 3, wherein the steering position sensor can be mounted to one of a plurality of locations on the rotatable steering column.

5. The modular front steering assembly of claim 3, wherein the rotatable steering column is articulated.

6. The modular front steering assembly of claim 1, wherein the progressive Ackerman effect induced by the steering mechanism is great enough to rotate the pair of wheel assemblies onto a common arc about a center of rotation of the vehicle.

7. The modular front steering assembly of claim 6, wherein the steering mechanism further comprises a mechanical linkage connecting the steering input device and the pair of wheel assemblies.

8. The modular front steering assembly of claim 7, wherein the mechanical linkage comprises a plurality of cooperative bevel and sector gears.

9. The modular front steering assembly of claim 8, wherein the sector gears have axes of rotation that are offset from center.

10. The modular front steering assembly of claim 7, wherein the mechanical linkage comprises a plurality of cooperative cams and cables.

11. The modular front steering assembly of claim 10, wherein the plurality of cooperative cams and cables comprises a first and second pair of cams having continually varying radii, the first pair of cams mounted to the vertical steering axis of one of the wheel assemblies and the second pair of cams mounted to the vertical steering axis of the other wheel assembly.

12. The modular front steering assembly of claim 6, wherein the steering mechanism further comprises a steer-by-wire assemblage operably connecting the steering input device and the pair of wheel assemblies.

13. The modular front steering assembly of claim 12, wherein the steer-by-wire assemblage comprises:

a pair of reduction gear assemblies in mechanical communication with the wheel assemblies, and

a pair of electric motors, each electric motor driving one of the reduction gear assemblies and capable of being communicatively connected with the electronic drive control system of the vehicle.

14. The modular front steering assembly of claim 13, further comprising a wiring harness connected to the pair of electric motors and to the steering position sensor.

15. The modular front steering assembly of claim 3, further comprising a steering column support connecting the frame member and the steering column.

16. The modular front steering assembly of claim 15, further comprising a cowling removably attached to at least one of the steering column, the steering column support and the frame member, to protect the steering mechanism and the steering position sensor.

17. The modular front steering assembly of claim 1, further comprising a weight mounting receptor attached to the frame member and adapted to receive a weight.

18. A modular front steering assembly adapted to integrate with a vehicle having a prime mover, a subframe, an accelerator, a brake, a power source, and a pair of variable drive units actuated by a mechanical combination, the modular front steering assembly comprising:

a frame member having opposed ends and adapted for attachment to the vehicle subframe;

a pair of wheel assemblies each attached proximate to one of the opposed ends of the frame member, each wheel assembly pivotable about a vertical steering axis;

a steering mechanism operatively connected to the pair of wheel assemblies;

an electronic drive control system adapted to independently adjust the speed and rotational direction of the output from each variable drive unit including;

a pair of electric actuators, each adapted for attachment to one of the variable drive units and to adjust the position of the mechanical combination;

a plurality of sensors and switches, each adapted for communication with one of either the steering mechanism, a variable drive unit, the prime mover, the power source, the accelerator or the brake;

a controller in communication with the plurality of sensors and switches, the pair of electric actuators, the prime mover and the power source; and

at least one wiring harness configured to place the controller in said communication.

19. The modular front steering assembly of claim 18, wherein the steering mechanism induces a progressive Ackerman effect in the pair of wheel assemblies great enough to rotate the pair of wheel assemblies onto a common arc about a center of rotation of the vehicle.

20. The modular front steering assembly of claim 19, wherein the steering mechanism further comprises a mechanical linkage connecting the steering mechanism and the pair of wheel assemblies.

21. The modular front steering assembly of claim 19, wherein the steering mechanism further comprises a steer by wire assemblage operatively connecting the steering mechanism and the pair of wheel assemblies.

22. The modular front steering assembly of claim 21, wherein the steering mechanism further comprises at least one electric motor electrically connected to the controller through the wiring harness and mechanically connected to the steering mechanism to rotate at least one wheel assembly about its vertical steering axis.

23. The modular front steering assembly of claim 19, wherein the sensor in communication with the steering mechanism transmits steering position signals to the controller which processes such signals in combination with signals from the plurality of sensors and switches to produce and transmit resultant signals to the pair of actuators, the actuators independently adjusting the speed of the output from each variable drive unit via adjustment of the respective mechanical combinations, whereby the vehicle is turned along an arc defined by the pair of wheel assemblies.