Steering system

Patent metadata

Field	Value
Publication number	US-11046354-B2
Application number	US-201916293864-A
Country	US
Kind code	B2
Filing date	Mar 6, 2019
Priority date	Mar 7, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A steering system for a vehicle, including an input shaft, via which a steering force can be input by a steering element, an output shaft acting on a steering actuating mechanism, a coupling for connecting and disconnecting the input shaft and the output shaft with and from each other, respectively, and at least one actuator, by which the coupling can be actuated to couple and uncouple the input shaft and the output shaft with and from each other, wherein in the uncoupled state, the output shaft is independently rotatable relative to the input shaft in such a manner that a steer-by-wire drive controllable by a control unit is provided.

First claim

The invention claimed is:

1. Steering system for a vehicle, comprising:
an input shaft via which a steering force is input from a steering element, an output shaft acting on a steering actuating mechanism, a coupling for connecting and disconnecting the input shaft and the output shaft with and from each other, respectively, and at least one actuator, by means of which the coupling can be actuated to couple and uncouple the input shaft and the output shaft with and from each other,
wherein in the uncoupled state, the output shaft is independently rotatable relative to the input shaft in such a manner that a steer-by-wire drive bidirectionally coupled to a control unit is provided, wherein the steer-by-wire drive is directed by the control unit to control the steering actuating mechanism and wherein the steer-by-wire drive is used by the control unit to determine the steering angle, and wherein in the coupled state, the input shaft and the output shaft are in a torque-proof connection with each other,
wherein the steering system is formed such that the at least one actuator controlled by the control unit can move the coupling into two discrete shift position, wherein in the first switch position, the coupling connects the input shaft and the output shaft in a torque-proof connection with each other, and in the second switch position, on the one hand, it uncouples the input shaft from the output shaft and on the other hand fixates the input shaft relative to a fixed part of the vehicle by a direct or indirect connection, and in that in the second switch position, the output shaft can be rotated by the control unit by means of the steer-by-wire drive independently of the input shaft.

2. A steering system according to claim 1 , wherein the direct or indirect connection between the input shaft and the fixed part of the vehicle in the second switch position is formed by at least one pivoting spring mechanism between the input shaft and the fixed part of the vehicle in such a manner that the input shaft can be rotated in both rotational directions against the force of the at least one spring mechanism by a predefined angle rate by means of the steering element connected with it, and reaches limit stops directly or indirectly connected with the fixed part of the vehicle in case of a rotation beyond this angle rate.

3. A steering system according to claim 2 , wherein the predefined angle rate is greater than 5° and less than 30°.

4. A steering system according to claim 2 , wherein the coupling is formed such that in the interim segment between the first switch position and the second switch position through which it moves dynamically, the coupling connects the input shaft and the output shaft with each other in a torque-proof connection during the transition from the first switch position to the second switch position, and fixates the input shaft relative to the fixed part of the vehicle in such a manner that the input shaft is at no time freely rotatable.

5. A steering system according to claim 4 , wherein the transition time of the interim segment is advantageously dimensioned such that when switching from the first switch position to the second switch position, the input shaft connected pivotably to the fixed part of the vehicle does not reach the limit stops when a steering force is applied to the input shaft.

6. A steering system according to claim 1 , wherein during standard operation, when switching from the second switch position to the first switch position, the control unit synchronizes the angle setting of the output shaft with the angle setting of the input shaft in such a manner that the steer-by-wire drive, controlled by the control unit, sets the steering actuating mechanism to the angle setting of the input shaft that was determined by means of at least one sensor and that the control unit then shifts the coupling into the first switch position by actuating the at least one actuator, and in particular, that the switching from the second switch position into the first switch position is done when the vehicle and/or the input shaft are in a stationary position.

7. A steering system according to claim 1 , wherein an emergency switch from the second switch position to the first switch position is provided, wherein when the emergency switch is triggered, the control unit brings the coupling into the first switch position by actuating the at least one actuator, independently of the angle setting of the input shaft, and that the coupling generates the respective connection in the first switch position or in the second switch position by way of a form-fitting connection, a frictional connection, or a force traction connection, and that the coupling features at least one switch element, wherein in the first switch position, the coupling connects the input shaft and the output shaft in a torque-proof connection with each other by means of the at least one switch element, and in the second switch position, on the one hand, it uncouples the input shaft from the output shaft, and on the other hand it fixates the input shaft relative to a fixed part of the vehicle by means of the at least one switch element.

8. A steering system according to claim 7 , wherein the coupling features two switch elements, wherein in the first switch position, the first switch element connects the input shaft and the output shaft with each other in a torque-proof connection, and in the second switch position disconnects the connection between the input shaft and the output shaft, whereas the second switch element in the second switch position fixates the input shaft relative to a fixed part of the vehicle and disconnects this connection in the first switch position.

9. A steering system according to claim 7 , wherein the at least one switch element can be actuated by means of the at least one actuator.

10. A steering system according to claim 1 , wherein the at least one actuator features a power-developing drive which is a member of one of the groups of electrical drives, mechanical drives, pneumatic drives, hydraulic drives, pyrotechnic drives, or any combination of these drives.

11. A steering system according to claim 3 , wherein the coupling is formed wherein in the interim segment between the first switch position and the second switch position through which it moves dynamically, the coupling connects the input shaft and the output shaft with each other in a torque-proof connection during the transition from the first switch position to the second switch position, and fixates the input shaft relative to the fixed part of the vehicle in such a manner that the input shaft is at no time freely rotatable.

12. A steering system according to claim 8 , wherein the at least one switch element can be actuated by means of the at least one actuator.

Assignees

• Audi Ag

Inventors

• Klinger Thomas

Classifications

• B62D5/005

  means for generating torque on steering wheel or input member, e.g. feedback · CPC title

• B62D15/0285

  Parking performed automatically · CPC title

• B62D5/001 Primary

  Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup · CPC title

• B60W50/16

  Tactile feedback to the driver, e.g. vibration or force feedback to the driver on the steering wheel or the accelerator pedal · CPC title

• B62D15/0215

  by measuring on the steering column · CPC title