Method for controlling a seat belt retractor

• US 20060097096A1
• Filed: 07/06/2005
• Published: 05/11/2006
• Est. Priority Date: 11/09/2004
• Status: Active Grant

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Heckmayr, Alexander
• Granted Patent: US 7,475,840 B2
• Time in Patent Office: Days
• US Class Current: 242/374
• CPC Class Codes: B60R 2022/4466 the additional retraction device being an electric actuator
• CPC Class Codes: B60R 2022/4666 characterised by electric actuators
• CPC Class Codes: B60R 22/44 with means for reducing belt tension during use under normal conditions not included in the retractor B60R22/19; B60R22/3405 takes precedence
• CPC Class Codes: B60R 22/46 Reels with means to tension the belt in an emergency by forced winding upelectrical circuits for triggering safety arrangements B60R21/01 ; tensioners using reels only guiding the belt during normal use, e.g. splitted reels B60R22/195
• CPC Class Codes: B60R 22/4628 characterised by fluid actuators, e.g. pyrotechnic gas generators actuating a cable B60R22/4619

Abstract

At least one function of a seat belt retractor by is controlled by an electric motor. Torque of which is transmitted from the electric motor via a coupling to at least one component of the seat belt retractor. After the application of the seat belt with the transmitted torque, the seat belt retractor is adjusted to a starting position for adjustable functions in normal driving conditions and in dangerous driving conditions.

Claims

1. A method for controlling at least one function of a seat belt retractor having an electric motor, the electric motor producing a torque that is transmitted via a coupling to at least one component of the seat belt retractor, whereby, after the application to a seat belt of the transmitted torque, the seat belt retractor is adjusted into a configuration, which is the starting configuration for adjustable functions in normal driving conditions and in dangerous driving conditions.

2. The method according to claim 1, wherein after the application to the seat belt of the transmitted torque slack is removed from the seat belt by the torque transmitted to a winding shaft of the seat belt retractor.

3. The method according to claim 1, wherein after the application to the seat belt of the transmitted torque, a motive spring of the seat belt retractor is rotated by the electric motor into a comfort position, in which the seat belt is applied with a reduced belt webbing force.

4. The method according to claim 2, wherein after the application to the seat belt of the transmitted torque, a motive spring of the seat belt retractor is rotated by the electric motor into a comfort position, in which the seat belt is applied with a reduced belt webbing force.

5. The method according to claim 1, wherein a component of the seat belt retractor can, from the function caused by the torque of the electric motor in normal driving conditions or in a dangerous situation, be brought back into the starting position with the aid of the torque created by the electric motor.

6. A method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor, the electric motor producing a torque that is transmitted via a coupling to at least one component of the seat belt retractor, whereby, after the application to a seat belt of the transmitted torque, the seat belt retractor is adjusted into a configuration, which is the starting configureation for adjustable functions in normal driving conditions and in dangerous driving conditions, wherein for the engagement of the coupling, a coupling part is accelerated by the motor above a determined acceleration threshold value.

7. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 6, wherein for the engagement of the coupling a tension pulse lasting a fraction of a revolution of the rotor is applied to the electric motor, in particular a direct current pulse in a first phase, and subsequently the electrical tension applied to the motor is reduced in a second phase to a tension value lower than the value of the first phase.

8. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 7, wherein the total timeframe of the first and second phases is shorter than one revolution of the rotor.

9. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 7, wherein after the second phase, the electrical tension applied to the motor in a third phase is lower than in the first phase.

10. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 7, wherein the electrical tension applied to the electric motor in the second phase is lower than in the third phase.

11. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 7, wherein to remove belt slack, the electrical tension is pole-reversed in the second phase in relation to the first phase.

12. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 7, wherein a current force of a motor current is reduced or adjusted after the second phase to a value required for a pre-tightening function or the removal of belt slack.

13. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 6, wherein for removal of belt slack the electric motor coupled to the winding shaft is driven with an increasing rotational speed until a determined belt force is achieved and/or that the hereby achieved rotational speed is maintained in a constant manner with a constant belt force, and that with a subsequent increasing belt force, the coupling is opened.

14. The method for transmitting a torque created by an electric motor via a coupling to a winding shaft of a seat belt retractor according to claim 6, wherein with an applied seat belt, to adjust the comfort in wear, the electric motor, coupled to the motive spring of the seat belt retractor, moves one of the two motive spring fixing points, in particular the outer fixing point, from a standard position, which is present in an applied seat belt with a removed belt slack, into a comfort position, in which the seat belt is applied with a reduced belt webbing force, whereby the electric motor is initially brought to a constant rotational speed with an increasing rotational speed, and that then the rotational speed is reduced to zero to achieve the comfort position of the motive spring.

15. A method for blocking a winding shaft of a seat belt retractor against further rotation by a belt webbing sensor which, at a determined pre-blocking rotational speed, brings the winding shaft into a pre-blocking position and, on further belt webbing extraction, into a blocking position, an electric motor producing a torque that is transmitted via a coupling to at least one component of the seat belt retractor, whereby, after the application to a seat belt of the transmitted torque, the seat belt retractor is adjusted into a configuration, which is the starting configuration for adjustable functions in normal driving conditions and in dangerous driving conditions, wherein the winding shaft is driven in a webbing winding direction at least for the removal of the belt slack with a determined belt force and in that subsequently the belt force is reduced for a revolution of the winding shaft in a webbing extraction direction for the control of the pre-blocking and main blocking function.

16. The method for blocking a winding shaft of a seat belt retractor against further rotation according to claim 15, wherein with an engaged coupling the determined belt force is initially maintained in a constant manner with the electric motor and then briefly reduced.

17. The method for blocking a winding shaft of a seat belt retractor against further rotation according to claim 15, wherein subsequent to the reduction of the belt force by the electric motor, the belt force is increased in a pulse-like manner by taking up of the belt webbing and decreased again, whereby during the reduction of the belt force, the winding shaft is rotated in the webbing extraction direction and the pre-blocking is controlled in a belt webbing sensitive manner and, on further belt extraction, the main blocking of the winding shaft is controlled.

18. The method for blocking a winding shaft of a seat belt retractor against further rotation according to claim 15, wherein during the control of the main blocking of the winding shaft, the coupling is opened.

19. The method for blocking a winding shaft of a seat belt retractor against further rotation according to claim 18, wherein for the opening of the coupling, the rotational direction of the electric motor is reversed and the motor rotational speed is reduced.

20. A method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction, an electric motor producing a torque that is transmitted via a coupling to at least one component of the seat belt retractor, whereby, after the application to a seat belt of the transmitted torque, the seat belt retractor is adjusted into a configuration, which is the starting configuration for adjustable functions in normal driving conditions and in dangerous driving conditions, wherein the winding shaft is driven by the coupled electric motor in a webbing winding direction, in particular with a gradually increasing belt force, to release a main blocking.

21. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein with a counter-force acting upon the belt webbing in the extraction direction, the winding shaft is driven in the webbing winding direction with a brief high acceleration surmounting the counter-force, to release the main blocking.

22. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claims 20, wherein to determine a rotational angle or a rotational speed or an acceleration of the winding shaft, the rotational movement of the winding shaft is sensed to detect the release of the main blocking.

23. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein the removal of slack from the applied belt webbing is controlled depending on a signal which is created by insertion of a buckle tongue attached to the belt webbing into a belt buckle.

24. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein the removal of slack from the applied belt webbing is controlled depending on a signal which indicates that a determined belt webbing length has been unwound from the winding shaft.

25. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein the state of the main blocking of the winding shaft against further rotation is detected by a detector.

26. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein an electrical sensing signal indicating a rotational movement of the winding shaft is forwarded to a computer located in a vehicle with the seat belt retractor.

27. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein an electrical sensing signal indicating the main blocking is forwarded to a computer located in a vehicle with the seat belt retractor.

28. The method for releasing the winding shaft of a seat belt retractor from a blocking position against further belt webbing extraction according to claim 20, wherein the coupling is activated in a rotational speed dependent or acceleration dependent manner by the electric motor.