Programmable seat belt damper assembly

• US 6,705,559 B1
• Filed: 06/14/1999
• Issued: 03/16/2004
• Est. Priority Date: 06/14/1999
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ginder, John Matthew, Sullivan, John L., Carr, Kirsten Marie
• Primary Examiner(s): NGUYEN, JOHN QUOC
• Application Number:
  US09/332,070
• Time in Patent Office: 1,737 Days
• Field of Search: 242/381, 242/384, 242/396.6, 280/805, 280/806, 280/807, 297/476, 297/477, 297/478
• US Class Current: 242/381
• CPC Class Codes: B60R 2022/282 using fluids or vico-elastic materials
• CPC Class Codes: B60R 2022/284 using electric or magnetic braking means
• CPC Class Codes: B60R 2022/287 of torsion rods or tubes
• CPC Class Codes: B60R 2022/288 with means to adjust or regulate the amount of energy to be absorbed
• CPC Class Codes: B60R 22/3413 operating between belt reel and retractor frame B60R22/4676 takes precedence

Abstract

A programmable seat belt damper assembly for a seat belt in a motor vehicle. The programmable seat belt damper assembly includes a retractor operatively connected to the seat belt for winding and unwinding the seat belt. The programmable seat belt damper assembly also includes a rotary damper operatively connected to the retractor and having a magneto-rheological (MR) fluid therein. The programmable seat belt damper assembly further includes a controller electrically connected to the rotary damper to control an apparent viscosity of the MR fluid to increase and decrease a damping torque of the rotary damper for the unwinding of the seat belt.

Claims

1. A programmable seat belt damper assembly for a seat belt in a motor vehicle comprising:

a retractor operatively connected to a seat belt for winding and unwinding the seat belt;

a rotary damper operatively connected to said retractor and having a magneto-rheological (MR) fluid therein; and

a controller electrically connected to said rotary damper and being programmable based on predetermined factors to send a signal thereto to generate a magnetic field to increase an apparent viscosity of said MR fluid to increase a damping torque of said rotary damper during an impact collision condition based on the predetermined factors, wherein the increased viscosity of the MR fluid permits some unwinding of the seat belt for highly damped occupant torso travel during the impact to reduce a kinetic energy of an occupant.

2. A programmable seat belt damper assembly as set forth in claim 1 wherein retractor has a rotatable shaft, said rotary damper being mounted about one end of said shaft.

3. A programmable seat belt damper assembly as set forth in claim 2 wherein said retractor has a take-up spool mounted on said shaft and connected to said seat belt.

4. A programmable seat belt damper assembly as set forth in claim 3 wherein said retractor includes a spring attached to another end of said shaft.

5. A programmable seat belt damper assembly as set forth in claim 2 wherein said rotary damper includes a housing disposed about and spaced from said shaft and having a cavity with open axial ends.

6. A programmable seat belt damper assembly as set forth in claim 5 wherein said rotary damper includes at least one driven member disposed in said cavity on and about said shaft.

7. A programmable seat belt damper assembly as set forth in claim 6 wherein said rotary damper includes a bearing disposed about said shaft and in each open axial end of said housing.

8. A programmable seat belt damper assembly as set forth in claim 7 wherein said rotary damper includes a coil disposed in said cavity and about said driven member and electrically connected to said controller.

9. A programmable seat belt damper assembly as set forth in claim 1 including an inertia sensor electrically connected to said controller to sense inertia of the motor vehicle.

10. A programmable seat belt damper assembly as set forth in claim 1 including at least one occupant sensor electrically connected to said controller to sense a profile of an occupant seated in the motor vehicle.

11. A programmable seat belt damper assembly for a motor vehicle comprising:

a seat belt;

a retractor operatively connected to said seat belt for winding and unwinding said seat belt;

a rotary damper operatively connected to said retractor and having a magneto-rheological (MR) fluid therein; and

a controller electrically connected to said rotary damper and being programmable based on predetermined factors to send a signal thereto to generate a magnetic field to increase an apparent viscosity of said MR fluid to increase a damping torque of said rotary damper during an impact collision condition based on the predetermined factors, wherein the increased viscosity of the MR fluid permits some unwinding of said seat belt for highly damped occupant torso travel during the impact to reduce a kinetic energy of an occupant.

12. A programmable seat belt damper assembly as set forth in claim 11 wherein retractor has a rotatable shaft, said rotary damper being mounted about one end of said shaft.

13. A programmable seat belt damper assembly as set forth in claim 12 wherein said rotary damper includes a bearing disposed about said shaft and in each open axial end of said housing.

14. A programmable seat belt damper assembly as set forth in claim 12 wherein said rotary damper includes a coil disposed in said cavity and about said driven member.

15. A programmable seat belt damper assembly as set forth in claim 12 wherein said rotary damper includes a housing disposed about and spaced from said shaft and having a cavity with open axial ends.

16. A programmable seat belt damper assembly as set forth in claim 15 wherein said rotary damper includes at least one driven member disposed in said cavity and about said shaft.

17. A programmable seat belt damper assembly as set forth in claim 11 including an inertia sensor electrically connected to said controller to sense inertia of the motor vehicle.

18. A programmable seat belt damper assembly for a motor vehicle comprising:

a seat belt;

a retractor having a rotatable shaft and a take-up spool on said shaft and connected to said seat belt for winding and unwinding said seat belt;

a rotary damper disposed about said shaft, said rotary damper having a housing with a cavity, a coil disposed in said cavity, a magneto-rheological (MR) fluid disposed in said cavity and a driven member made of a ferrous material connected to said shaft and disposed in said cavity within said coil; and

a controller electrically connected to said coil of said rotary damper and being programmable based on predetermined factors to send a signal thereto to generate a magnetic field to increase an apparent viscosity of said MR fluid to increase a damping torque of said driven member during an impact collision condition based on the predetermined factors, wherein the increased viscosity of the MR fluid permits some unwinding of said seat belt for highly damped occupant torso travel during the impact to reduce a kinetic energy of an occupant.