Belt retractor with an electromotive winding aid and method for activating an electromotive winding aid for a belt retractor
AssigneeAutoliv Development AB
InventorsPatrick Süllau, Andreas Lucht, Hans-Jörg Langhoff, Hans-Otto Kock, Philip Rings
Life of this patent
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Abstract
The invention relates to a belt retractor with an electromotive winding aid (4) comprising a belt shaft (1) which is pretensioned in the winding-up direction by a spring and is mounted rotatably in a frame (3) of the belt retractor on which a belt strap (2) can be wound up. The electromotive winding aid (4) can be activated as a function of the belt-strap-retraction speed (BRS).
Claims11
A seat belt retractor for a seat belt comprising:
- a belt shaft rotatably mounted in a frame of the seat belt retractor for winding the seat belt and a retractor spring for pretensioning the seat belt in a direction of winding of the seat belt;
- an electromotive winding aid acting on the belt shaft;
- and
- a control device for controlling the electromotive winding aid as a function of a seat belt feed rate,
- wherein the retractor spring provides a return force in the direction of winding of the seat belt, and the electromotive winding aid provides a further return force in the direction of winding, such that the return force and the further return force are added together to form a constant total return force or a total return force that corresponds to a predetermined curve to wind the seat belt in the direction of winding.
A method to control an electromotive winding aid of a seat belt retractor which acts on a belt shaft to wind a seat belt, the method comprising:
- activating the electromotive winding aid, when a belt lock sensor does not sense a locked belt tongue;
- providing a sensor device to sense a seat belt feed rate;
- and
- determining,by a control device, the sensed seat belt feed rate is below a predetermined first boundary value,
- wherein a retractor spring provides a return force in a direction of winding of the seat belt, and the electromotive winding aid provides a further return force in the direction of winding, such that the return force and the further return force are added together to form a constant total return force or a total return force that corresponds to a predetermined curve to wind the seat belt in the direction of winding.
Dependencies are inferred from the claim text.