Electrically actuated vehicle steering system

• US 6,213,246 B1
• Filed: 01/15/1999
• Issued: 04/10/2001
• Est. Priority Date: 01/16/1998
• Status: Expired due to Term

• Current Assignee: Chemtron Research LLC (Intellectual Ventures LLC)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Moser, Martin, Schneckenburger, Reinhold, Bohner, Hubert
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US09/231,675
• Time in Patent Office: 816 Days
• Field of Search: 180/402, 180/403, 180/405, 180/406, 180/407
• US Class Current: 180/403
• CPC Class Codes: B62D 5/003 Backup systems, e.g. for manual steering B62D5/30 takes precedence

Abstract

In a steering system for a motor vehicle, the steered vehicle wheels, during normal operation, are coupled with a steering handle only through an electronic regulating system that constantly checks for correct function. The regulating system controls an actuator for the steering adjustment of the steered vehicle wheels in response to a signal from a set value transmitter which is actuated by the steering handle. During abnormal operation, a mechanical or hydraulic forced coupling is introduced between the steering handle and the steered vehicle wheels. At the same time the actuator and/or a manual force adjuster associated with the steering handle operate as a servo motor.

Claims

1. Steering system for a motor vehicle having steered vehicle wheels that are coupled to a steering handle during normal operation by an electronic regulating system that constantly checks for correct function, said regulating system being connected with a steering angle setpoint generator actuated by the steering handle and with a steering angle setpoint sensor actuated by the steered vehicle wheels for regulating a steering actuator for adjusting the steered vehicle wheels, and being further connected with at least one first sensor which generates signals indicative of forces transmitted between the steering actuator and the steered vehicle wheels, as well as a manual force actual value sensor that detects forces transmitted between a manual force adjusting device and the steering handle, regulating a manual force setting device connected with steering handle to simulate a steering resistance wherein:

said steered vehicle wheels are forcibly coupled with the steering handle during abnormal or emergency operation, for adjusting steering via the steering handle;

during forcible coupling of steering handle and steered vehicle wheels, the manual force actual value sensor detects steering forces transmitted between the steering handle and the steered vehicle wheels;

the regulating system controls one of the manual force adjuster and the steering actuator in the manner of a servo motor to reduce manual forces required during steering maneuvers, with hydraulic forced coupling being provided for abnormal operation or emergency operation between steering handle and steered vehicle wheels;

second sensors are mounted on a hydraulic system that produces hydraulic force coupling for generating signals indicative of leaks in the hydraulic system; and

said regulating system includes apparatus for analyzing signals of the second sensors during hydraulic forced coupling of steering handle and steered vehicle wheels, to determine forces transmitted between steering handle and steered vehicle wheels.

2. The steering system according to claim 1, wherein during forcible coupling of the steering handle and steered vehicle wheels, an electronic subsystem of the regulating system acts as a servo motor to actuate one of the manual force adjuster and the steering actuator.

3. The steering system according to claim 1, wherein the steering actuator comprises a servo motor, which is operable as a function of the signals from pressure sensors.

4. The steering system according to claim 1, wherein:

an electric motor is provided as a steering actuator;

said electric motor cooperates as a manual force setpoint transmitter with the regulating system, which obtains electrical operating parameters from electric motor which are correlated to the forces transmitted between the steering actuator and steered vehicle wheels.

5. A steering system for a vehicle having steered vehicle wheels, comprising:

a steering input device for receiving a driver command for steering said vehicle wheels;

a first selectively operative manually driven coupling between said steering input device and said steered vehicle wheels, for adjusting a steering angle thereof,

a second selectively operative coupling between said steering device and said steered vehicle wheels for adjusting a steering angle thereof, which second selectively actuatable coupling is selectively operable in parallel with said first selectively operative coupling;

at least one first sensor for continuously monitoring proper functioning of said second selectively operative coupling; and

a regulating system for controlling said first and second selectively operative couplings;

wherein

said regulating system causes said first selectively operative coupling to be inoperative during normal functioning of said second selectively operative coupling; and

during a detected abnormal functioning of said second selectively operative coupling, said regulating system causes said first selectively operative coupling to become operative, and causes said second selectively operative coupling either to become inoperative or to operate to provide a power assist to said first selectively operative coupling, depending on a nature of said abnormal functioning;

wherein said second selectively operable coupling includes;

a power assist unit coupled to assist manual driving of said first selectively operative coupling; and

at least one second sensor for detecting a steering force exerted on said steered vehicle wheels;

at least one third sensor for detecting a force transmitted between said steering input device and said steered wheels;

wherein

during normal functioning of said second selectively operative coupling, said regulating system causes said power assist unit to exert a force on said steering input device as a function of signals from said at least one second sensor and said at least one third sensor,

during a detected abnormal functioning of said second selectively operative coupling, said regulating system actuates said power assist unit to assist forces exerted on steering input device as a function of signals from said at least one third sensor.

6. The steering system according to claim 5, wherein

said second selectively operative coupling is actuated by one of hydraulic, pneumatic and hydrostatic pressure; and

said at least one first sensor comprises at least one sensor for determining pressure generated in said second selectively operative coupling.

7. The steering system according to claim 5, wherein

said second selectively operative coupling is actuated by one of hydraulic, pneumatic and hydrostatic pressure;

and

said at least one first sensor comprises at least one sensor for determining pressure generated in said second selectively operative coupling.

8. The steering system according to claim 7 wherein said at least one second sensor comprises said at least one first sensor.