BELT RETRACTOR UTILIZING ACTIVE MATERIAL ACTUATION

• US 20090267339A1
• Filed: 04/22/2009
• Published: 10/29/2009
• Est. Priority Date: 04/23/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Gao, Xiujie, Usoro, Patrick B., Mankame, Nilesh D., Browne, Alan L., Johnson, Nancy L., Mc Knight, Geoffrey P., Herrera, Guillermo A., Carter, William B., Corrion, Steven G., Maugh, Lawrence C.
• Granted Patent: US 8,262,133 B2
• Time in Patent Office: Days
• US Class Current: 280/807
• CPC Class Codes: B60R 2022/4685 with means to adjust or regulate the tensioning force in relation to external parameters
• CPC Class Codes: B60R 22/4676 comprising energy-absorbing means operating between belt reel and retractor frame

Abstract

A seat belt retractor utilizing active material actuation for selectively modifying the tension in a seat belt.

Claims

1. A seat belt retractor adapted for use with a seat belt presenting a first tensile load, said retractor comprising:

a tensioning mechanism coupled to the belt and including an active material element operable to undergo a reversible change in fundamental property when exposed to or occluded from an activation signal,

said mechanism being configured to selectively adjust the tension in the belt to a second tensile load, as a result of the change.

2. The retractor as claimed in claim 1, wherein the mechanism is further configured to gradually adjust the tension, so as to present digressive load limiting.

3. The retractor as claimed in claim 1, wherein the belt includes a webbing, the webbing is fixedly coupled to a bolt, and the mechanism includes a flange defining an hour-glass slot and formed of normally Austenitic SMA.

4. The retractor as claimed in claim 1, wherein the belt is drivenly coupled to a piston housed in a chamber further filled with a fluid, the chamber is fluidly coupled to an orifice selectively encroached by an MR restrictor, such that translation of the piston causes the restrictor to recede from the orifice at a rate, and the change modifies the rate.

5. The retractor as claimed in claim 1, wherein the mechanism includes first and second inter-engaged parts, and the first part is able to transmit a first maximum torque or force to the second part when the element is activated and a second maximum torque or force when deactivated.

6. The retractor as claimed in claim 5, wherein the mechanism includes inner and outer concentric tubes having respective torsional strengths, the outer tube presents an internal gear having radially inner teeth, the element presents a plurality of outer gear teeth fixedly secured to the inner tube, and said inner and outer teeth being inter-meshed.

7. The retractor as claimed in claim 5, wherein a plurality of torque-transmitting spheres are fixed to a first of the tubes and contact the other, so as to be intermediately disposed therebetween, and the element is operable to cause the tubes to relatively translate so as to reduce or increase the plurality of spheres.

8. The retractor as claimed in claim 1, wherein the belt includes a webbing, the mechanism includes at least one part drivenly coupled to the element, and said at least one part is configured to engage the webbing and operable to adjust the tension in the belt, when the element is activated.

9. The retractor as claimed in claim 8, wherein first and second parts define first and second opposite surfaces and a gap therebetween, the webbing is caused to pass through the gap, each surface defines pluralities of protrusions extending therefrom, and the protrusions are caused to variably engage the webbing when the element is activated and deactivated.

10. The retractor as claimed in claim 8, wherein the mechanism includes a rotational frame pivotally coupled to a gear, a torsional spring drivenly coupled to the frame and gear, and a latch, and the element is configured to cause the latch to selectively engage the gear, so as to prevent rotation by the gear, cause the spring to store energy when the frame is pivoted, and adjust the tension in the belt.

11. The retractor as claimed in claim 1, wherein the mechanism includes a multi-component torsion bar operable to present first and second torsional strengths when the element is activated and deactivated respectively.

12. The retractor as claimed in claim 11, wherein the bar includes inner and outer tubes, the outer tube is deformable and defines an internal groove, a cable is fixedly connected to the inner tube and entrained within the groove, and the element is drivenly coupled to the outer tube and operable to cause the outer tube to deform so as to increase frictional engagement with the cable when activated.

13. The retractor as claimed in claim 11, wherein the bar includes integral pluralities of SMA and spring steel disk segments.

14. The retractor as claimed in claim 11, wherein the bar includes a plurality of disk segments spaced by at least one separator spring, and the element is antagonistic to said at least one spring, and operable to variably deform said at least one spring so as to result in first and second torsional strengths when activated and deactivated respectively.

15. The retractor as claimed in claim 11, wherein the bar includes inner and outer concentric tubes having respective torsional strengths, and the tubes are caused to inter-engage by the change.

16. The retractor as claimed in claim 15, wherein the tubes are selectively caused to engage by an actuator selected from the group consisting essentially of expansion dutches, brakes, and collars.

17. The retractor as claimed in claim 1, further comprising:

a controller communicatively coupled to the mechanism; and

at least one sensor communicatively coupled to the controller, and operable to detect a condition or event,

said controller and sensor being cooperatively configured to cause the element to be exposed to or occluded from the signal upon detection of the event.

18. The retractor as claimed in claim 17, wherein said at least one sensor is operable to determine occupant anthropometry and position.

19. The retractor as claimed in claim 17, wherein said at least one sensor includes a pre-crash, or crash sensor.

20. The retractor as claimed in claim 19, wherein said at least one sensor is operable to determine a crash characteristic selected from the group consisting essentially of closing velocity, vehicle crush pulse, and the type of object being impacted.