Retractor pretensioner assembly

Patent metadata

Field	Value
Publication number	US-9555768-B2
Application number	US-201414286184-A
Country	US
Kind code	B2
Filing date	May 23, 2014
Priority date	May 23, 2014
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A pretensioner assembly for motor vehicle belt restraint systems is provided. The pretensioner assembly includes a tube in fluid communication with a gas generator and a driving element disposed therein that travels in a first direction in response to actuation of the gas generator. The tube includes a constriction disposed adjacent an exit of the tube. The constriction allows the driving element to pass but prevents a seal member disposed between the generator and the driving element from passing. The constriction provides backpressure on the seal member causing the seal member to expand radially outward. The system can also include a slug member disposed between the seal member and the driving element.

First claim

The invention claimed is:

1. A seatbelt pretensioning retractor assembly for use in a passenger vehicle, the system comprising:
a housing adapted for being mounted to a vehicle structure;
a tube having an arcuate and curved shape having a first end in fluid communication with a gas generator and a second end in fluid communication with an interior cavity of the housing;
a sprocket rotatably mounted to the housing and fixedly coupled to a spindle adapted for taking up seatbelt webbing during pretensioning, the sprocket having a plurality of vanes;
at least one driving element disposed within the tube and translatable through the tube in a first direction toward the sprocket in response to an actuation by the generator;
a seal member disposed between the generator and the at least one driving element;
wherein the tube includes a constriction portion having an opening smaller than the width of adjacent portions of the tube and disposed adjacent the exit, the constriction portion sized to permit the driving element to pass therethrough and to prevent the seal member from passing therethrough.

2. The assembly of claim 1 , wherein the seal member extends across the width of the tube to prevent gas or fluids from traveling beyond the seal member.

3. The assembly of claim 1 , wherein the constriction portion is integrally formed with the tube.

4. The assembly of claim 3 , wherein the constriction portion is in the form of a bump in a sidewall of the tube.

5. The assembly of claim 4 , wherein a sidewall of the tube has a constant thickness through the constriction portion.

6. The assembly of claim 3 , wherein the constriction portion is in the form a protrusion.

7. The assembly of claim 1 , wherein the constriction portion is in the form of a separate constriction member fixedly mounted to an interior of the tube.

8. The assembly of claim 1 , wherein the constriction portion extends around the entire circumference of the tube.

9. The assembly of claim 1 , wherein the constriction portion extends around a portion of the circumference of the tube that is less than the entire circumference.

10. The assembly of claim 1 , wherein the constriction portion and adjacent portions of the tube form a monolithic structure.

11. The assembly of claim 1 , wherein the constriction portion is located on an inboard portion of the tube.

12. The assembly of claim 1 further comprising a slug member disposed between the seal member and the driving element, wherein the constriction prevents the slug member from passing therethrough.

13. The assembly of claim 12 , wherein the slug member is harder than the seal member.

14. The assembly of claim 12 , wherein the seal member and slug member are generally spherical.

15. The assembly of claim 1 , wherein the seal member expands circumferentially outward in response to backpressure from the constriction member during actuation of the generator.

16. The assembly of claim 1 , wherein the driving element is a plurality of balls.

17. The assembly of claim 1 , wherein the driving element is a plastically deformable polymer rod.

18. The assembly of claim 17 , wherein the polymer rod is locked against translation in a second direction opposite that is opposite the first direction after the polymer rod has engaged the sprocket to provide pretensioning.

19. The assembly of claim 18 , wherein the polymer rod is locked via a welding connection between the polymer rod and a guide portion of the housing disposed within the interior cavity of the housing, wherein the welding connection occurs in response to heat generated between the polymer rod and the guide portion.

20. A seatbelt pretensioning retractor assembly for use in a passenger vehicle, the system comprising:
a housing adapted for being mounted to a vehicle structure;
a tube having an arcuate and curved shape having a first end in fluid communication with a gas generator and a second end in fluid communication with an interior cavity of the housing;
a sprocket rotatably mounted to the housing and fixedly coupled to a spindle adapted for taking up seatbelt webbing during pretensioning, the sprocket having a plurality of vanes;
at least one driving element disposed within the tube and translatable through the tube in a first direction toward the sprocket in response to an actuation by the generator;
a seal member disposed between the generator and the at least one driving element;
wherein the tube includes a constriction portion having an opening smaller than the width of adjacent portions of the tube and disposed adjacent the exit, the constriction portion sized to permit the driving element to pass therethrough and to prevent the seal member from passing therethrough;
wherein the constriction portion comprises a plate inserted through a hole defined in the sidewall of the tube.

Assignees

• Autoliv Asp
• Autoliv Asp Inc

Inventors

• Gray Mark F
• Kohlndorfer Kenneth H

Classifications

• B60R22/4628 Primary

  characterised by fluid actuators, e.g. pyrotechnic gas generators (actuating a cable B60R22/4619) · CPC title

• B60R2022/4642

  the gas directly propelling a flexible driving means, e.g. a plurality of successive masses, in a tubular chamber · CPC title