Seat belt retractor

• US 20050134101A1
• Filed: 12/10/2004
• Published: 06/23/2005
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Hiramatsu, Koji, Kitazawa, Kenji
• Granted Patent: US 7,350,735 B2
• Time in Patent Office: Days
• US Class Current: 297/472
• CPC Class Codes: B60R 2022/285 using friction surfaces
• 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 22/341 comprising energy-absorbing means
• CPC Class Codes: B60R 22/4676 comprising energy-absorbing means operating between belt reel and retractor frame

Abstract

A seat belt system includes a retractor and a seat belt. The retractor includes a motor that drives a pressure rod into a seat belt such that the seat belt is nipped between the pressure rod and belt receiving portions. The driving force of the motor that controls the movement of the pressure rod is set based on the situation at the time of a collision. Thus, the load limit to be exerted on the seat belt is set flexibly and widely according to the situation in an emergency. Further, the motor and the pressure piston rod can be activated repeatedly and, therefore, can be reused.

Claims

1. A seat belt retractor comprising:

a spool for retracting a seat belt;

a locking mechanism including a locking member of which rotation in a belt-withdrawing direction is prevented in an emergency; and

first and second seat belt load limiting mechanisms for limiting a load to be exerted on the seat belt when rotation of the locking member in the belt-withdrawing direction is prevented with the spool rotating relative to the locking member in the belt-withdrawing direction,

wherein the second seat belt load limiting mechanism comprises;

load limit setting means for setting a load limit for the seat belt; and

load limit control means for controlling the load limit setting means to change the load limit of the seat belt in an emergency based on the situation in the emergency, and

wherein the load limit setting means is configured to be reused.

2. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a torsion bar provided between the spool and the locking member.

3. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for drawing a wire rod provided on either a spool side or a locking base side and through engagement pins provided on the other side.

4. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for forcing a band plate provided on either one of a spool side and a locking base side to be forcibly deformed by a guide slot provided on the other side.

5. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for subjecting a tubular member provided on either one of a spool side and a locking base side to plastic deformation with a latching portion provided on the other side.

6. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for subjecting a U-shaped flat plate material of which one end is provided on either one of a spool side and a locking base side and the other end of which is engaged with the other side.

7. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for subjecting a shear pin provided between a spool and a locking base to shear fracturing.

8. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is an energy absorption mechanism for cutting a section to be cut provided on either a spool side and a locking base side with a cutting blade provided on the other side.

9. The seat belt retractor according to claim 1, wherein the first seat belt load limiting mechanism is a load limiting mechanism for severing a plate-shaped energy absorption member provided on either a spool side and a locking base side with a severing protrusion provided on the other side.

10. The seat belt retractor according to claim 1, wherein the load limit of the seat belt is set in an emergency to one of three modes:

(a) an inoperative load mode;

(b) a light load mode;

(c) and a heavy load mode.

11. A seat belt retractor comprising:

a spool for retracting a seat belt;

a locking mechanism including a locking member a rotation of which in a belt-withdrawing direction is prevented in an emergency;

a first seat belt load limiting mechanism that is configured to define a first load limit on the seat belt; and

a second seat belt load limiting mechanism that is programmable to define a second load limit on the seat belt,

wherein the first and second load limits in sum define a load limit on the seat belt, and

wherein the first and second seat belt load limiting mechanisms are configured to limit a load to be exerted on the seat belt when rotation of the locking member in the belt-withdrawing direction is prevented during the emergency.

12. The seat belt retractor according to claim 11, wherein the second seat belt load limiting mechanism is configured to be reused.

13. The seat belt retractor according to claim 11, wherein the second seat belt load limiting mechanism comprises:

a motor; and

a piston driven by the motor into contact with the seat belt during the emergency.

14. The seat belt retractor according to claim 11, wherein the second load limit is based on one or more signals measured by one or more sensors at the time of the emergency, wherein the signals represent situation characteristics at the time of the emergency.

15. The seat belt retractor according to claim 14, wherein the one or more signals are any one or more of:

a signal corresponding to the weight of an occupant to be restrained by the seat belt;

a signal corresponding to the position of a seat on which an occupant to be restrained by the seat belt sits;

a signal corresponding to the speed of a vehicle containing the seat belt retractor;

a signal corresponding to an impact location of a collision defining the emergency; and

a signal corresponding to whether a buckle tongue that is attached to the seat belt is engaged with a buckle latch.

16. The seat belt retractor according to claim 14,

wherein the second seat belt load limiting mechanism comprises:

a motor; and

a piston driven by the motor into contact with the seat belt during the emergency, and

wherein a degree to which the piston is driven during the emergency is reflective of the one or more signals.

17. The seat belt retractor according to claim 11, wherein the load limit of the seat belt is set in an emergency to one of three modes:

(a) an inoperative load mode;

(b) a light load mode;

(c) and a heavy load mode.

18. The seat belt retractor according to claim 17,

wherein in the inoperative load mode, the second seat belt load limiting mechanism is not activated,

wherein in the light load mode, the second seat belt load limiting mechanism is activated, and

wherein in the heavy load mode, the second seat belt load limiting mechanism is activated to a greater degree than in the light load mode.

19. The seat belt retractor according to claim 11, wherein the first seat belt load limiting mechanism is a torsion bar provided between the spool and the locking member.

20. A seat belt system comprising:

a seat belt comprising a tongue;

a seat belt buckle comprising a latch configured to releasably engage the tongue; and

a seat belt retractor configured to retract the seat belt on a spool provided in the seat belt retractor, the seat belt retractor comprising;

a locking mechanism including a locking member a rotation of which in a belt-withdrawing direction is prevented in an emergency;

a first seat belt load limiting mechanism that is configured to define a first load limit on the seat belt; and

a second seat belt load limiting mechanism that is programmable to define a second load limit on the seat belt,

wherein the first and second load limits in sum define a load limit on the seat belt, and

wherein the first and second seat belt load limiting mechanisms are configured to limit a load to be exerted on the seat belt when rotation of the locking member in the belt-withdrawing direction is prevented during the emergency.

21. The seat belt system according to claim 20, wherein the second seat belt load limiting mechanism is configured to be reused.

22. The seat belt system according to claim 20, wherein the second seat belt load limiting mechanism comprises:

a motor; and

a piston driven by the motor into contact with the seat belt during the emergency.

23. The seat belt system according to claim 20, wherein the second load limit is based on one or more signals measured by one or more sensors at the time of the emergency, wherein the signals represent situation characteristics at the time of the emergency.

24. The seat belt system according to claim 23, wherein the one or more signals are any one or more of:

a signal corresponding to the weight of an occupant to be restrained by the seat belt;

a signal corresponding to the position of a seat on which an occupant to be restrained by the seat belt sits;

a signal corresponding to the speed of a vehicle containing the seat belt retractor;

a signal corresponding to an impact location of a collision defining the emergency; and

a signal corresponding to whether the tongue is engaged with the latch.

25. The seat belt system according to claim 23,

wherein the second seat belt load limiting mechanism comprises:

a motor; and

a piston driven by the motor into contact with the seat belt during the emergency, and wherein a degree to which the piston is driven during the emergency is reflective of the one or more signals.

26. The seat belt system according to claim 20, wherein the load limit of the seat belt is set in an emergency to one of three modes:

(a) an inoperative load mode;

(b) a light load mode;

(c) and a heavy load mode.

27. The seat belt system according to claim 26,

wherein in the inoperative load mode, the second seat belt load limiting mechanism is not activated,

wherein in the light load mode, the second seat belt load limiting mechanism is activated, and

wherein in the heavy load mode, the second seat belt load limiting mechanism is activated to a greater degree than in the light load mode.

28. The seat belt system according to claim 20, wherein the first seat belt load limiting mechanism is a torsion bar provided between the spool and the locking member.