Seat belt retractor assembly

Patent metadata

Field	Value
Publication number	US-10625709-B2
Application number	US-201816132833-A
Country	US
Kind code	B2
Filing date	Sep 17, 2018
Priority date	Sep 17, 2018
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A seat belt retractor for use with a seat belt webbing includes a spindle, a tread head part, a torsion bar, a stop nut and an energy management element. The spindle is configured for winding the seat belt webbing around the spindle. The tread head part is configured for having a locked condition or a free condition. The torsion bar is engaged with the spindle and the tread head part and configured to deflect torsionally by allowing relative rotation between the spindle and the tread head part when the tread head part is in the locked condition. The stop nut is operatively coupled with the tread head part and the spindle and configured to move in axial direction. Furthermore, the energy management element placed between the stop nut and the tread head part is configured to be deformed by the axial movement of the stop nut.

First claim

What is claimed is:

1. A seat belt retractor for use with a seat belt webbing, the seat belt retractor comprising:
a spindle configured to wind the seat belt webbing around the spindle;
a tread head part configured to have a locked condition or a free condition;
a torsion bar operatively coupled between the spindle and the tread head part, the torsion bar configured to deflect torsionally by allowing relative rotation between the spindle and the tread head part when the tread head part is in the locked condition;
a stop nut operatively coupled with the tread head part and the spindle, the stop nut configured to move in an axial direction when the spindle is rotated relative to the tread head part in the locked condition of the tread head part; and
an energy management element operatively coupled between the tread head part and the spindle, the stop nut deforming the energy management element upon the movement in the axial direction thereby resisting the relative rotation between the tread head part and the spindle for controlling a force exerted by the seat belt webbing.

2. The seat belt retractor of claim 1 , wherein the tread head part has a cylindrical shape with a step portion that is concentric with the spindle.

3. The seat belt retractor of claim 2 , wherein the step portion of the tread head part is extended inside the spindle and has an external thread portion engaged with the stop nut.

4. The seat belt retractor of claim 3 , wherein the stop nut is concentric with the spindle, and the stop nut has an internal thread portion for being screwed with the external thread portion of the tread head part.

5. The seat belt retractor of claim 1 , wherein the stop nut is engaged with the spindle and the stop nut is configured to rotate together with the spindle when the tread head part is in the locked condition.

6. The seat belt retractor of claim 5 , wherein the rotation of the stop nut with the spindle relative to the tread head part is configured for allowing the stop nut to move axially toward a base end of the tread head part.

7. The seat belt retractor of claim 1 , wherein the stop nut has squared-shape teeth projected radially outward on an outer periphery, and the squared-shape teeth is fitted into the spindle.

8. The seat belt retractor of claim 1 , wherein the torsion bar is placed inside the spindle with a cylindrical shape, and wherein the torsion bar is coaxially engaged with the spindle at a first end of the torsion bar and engaged with the tread head part at a second end of the torsion bar.

9. The seat belt retractor of claim 1 , wherein the torsion bar is configured to absorb energy by allowing the relative rotation between the spindle and the tread head part when the tread head part is in the locked condition.

10. The seat belt retractor of claim 1 , wherein the energy management element has a ring shape and is concentric with the spindle and placed between the stop nut and the tread head part.

11. The seat belt retractor of claim 10 , wherein the stop nut deforms the energy management element for progressively increasing a clamping force between the stop nut and the tread head part when the spindle is rotated a predetermined number of times relative to the tread head part in the locked condition of the tread head part.

12. The seat belt retractor of claim 10 , wherein the deformed energy management element is configured to expand radially into increasing contact for friction interaction between the stop nut and the tread head part.

13. The seat belt retractor of claim 1 , wherein the energy management element is configured to increase the resistance to the seat belt webbing extraction while the relative rotation of the spindle with regard to the tread head part is controlled by the torsion bar in the locked condition of the tread head part.

14. The seat belt retractor of claim 1 , wherein the tread head part includes a tread head and a tread head insert being a cylindrical shape, and the tread head and the tread head insert are concentric with the spindle and coaxially engaged with each other.

15. The seat belt retractor of claim 14 , wherein the tread head has inner bore teeth in an inner bore and cavities on an outer periphery, and wherein the cavities are configured for allowing the seat belt retractor to move in the locked condition or the free condition by coupling to the locking system.

16. The seat belt retractor of claim 15 , wherein the tread head insert has outer teeth, and the outer teeth of the tread head insert is press fitted into the inner bore of the tread head for allowing no relative rotation between the tread head insert and the tread head.

17. The seat belt retractor of claim 14 , wherein the tread head and the tread head insert are made of different materials.

Assignees

• Autoliv Asp Inc

Inventors

• Hall Christopher D
• Burrow Jon E

Classifications

• B60R2022/287

  of torsion rods or tubes · CPC title

• B60R22/3413 Primary

  operating between belt reel and retractor frame (B60R22/4676 takes precedence) · CPC title

• B60R22/341 Primary

  comprising energy-absorbing means · CPC title

• B60R22/36

  self-locking in an emergency ({B60R22/3405} , B60R22/343 take precedence) · CPC title