WO2012014380A1 - Seatbelt retractor and seatbelt device using same - Google Patents

Abstract

A load acting on a seatbelt is limited by a torsion bar (12) when a spool (9) and a rocking base (20) are rotated relative to each other. When the spool (9) is rotated a predetermined amount relative to the rocking base (20), a stopper (23) presses an EA member (27) to grip the EA member (27) between the stopper (23) and the body section (20a) of the rocking base (20). When the spool (9) is further rotated relative to the rocking base (20), the stopper (23) presses and crushes the EA member (27) to perform a seatbelt load limiting operation. When the movement of the stopper (23) is stopped, the seatbelt load limiting operation by the torsion bar (12) is completed. Thus, the seatbelt load limiting operation by the EA member (27) is performed immediately before the seatbelt load limiting operation by the torsion bar (12) is completed.

Description

Seat belt retractor and seat belt device using the same

In the present invention, an energy absorbing member (hereinafter also referred to as an EA member) is used to prevent a seat belt from being pulled out in an emergency such as when a large vehicle deceleration is applied to a vehicle in a collision state with the seat belt mounted. The present invention belongs to the technical field of a seat belt retractor that limits a load (that is, a seat belt tension) applied to the seat belt by absorbing the kinetic energy of the seat belt and a seat belt device using the seat belt retractor.

Conventionally, a vehicle such as an automobile has been equipped with a seat belt device in order to restrain an occupant with a seat belt in the case of the aforementioned emergency. FIG. 12 is a diagram schematically showing a conventional general seat belt device. In FIG. 12, 1 is a seat belt device, 2 is a vehicle seat, 3 is a seat belt retractor disposed in the vicinity of the vehicle seat 2, and 4 is retracted by the seat belt retractor 3 so as to be retractable, and a belt anchor 4a at the front end. Is fixed to the floor of the vehicle body or the vehicle seat 2, 5 is a guide anchor for guiding the seat belt 4 pulled out from the seat belt retractor 3 toward the occupant's shoulder, and 6 is guided from this guide anchor 5. A tongue 7 slidably supported on the seat belt 4 is a buckle fixed to the floor of the vehicle body or the vehicle seat and into which the tongue 6 is detachably inserted.

In such a seat belt device 1, the tongue 6 is disengaged from the buckle 7 when the seat belt 4 is not worn, so that all the amount that can be wound around the spool of the seat belt retractor 3 is wound. When the seat belt 4 is mounted, the seat belt 4 is pulled out from the seat belt retractor 3 by a predetermined amount, and the tongue 6 is inserted and engaged with the buckle 7. The seat belt retractor 3 is prevented from being pulled out by the lock mechanism being operated in an emergency as described above to prevent rotation of the spool in the pulling direction. Thereby, the seat belt 4 effectively restrains the occupant in an emergency.

By the way, in the seat belt retractor 3 of the conventional seat belt device 1, when the seat belt 4 restrains the occupant in an emergency, a large vehicle deceleration occurs, so the occupant tries to move forward due to a large inertia. For this reason, a large load is applied to the seat belt 4 and the occupant receives a load from the seat belt 4. For this reason, it is desirable to reduce this load and to do it more finely according to the emergency situation.

Therefore, in the conventional seat belt retractor, various seat belt retractors are proposed in which the kinetic energy of the occupant is absorbed and the load applied to the seat belt is limited when a load due to the inertia force of the occupant is applied to the seat belt in an emergency. (For example, refer to Patent Document 1).

FIG. 13 is a longitudinal sectional view showing an example of a seat belt retractor using such a torsion bar and a shear pin.
In FIG. 13, 8 is a U-shaped frame, 9 is rotatably disposed between both side walls of the U-shaped frame 8, and a spool for winding the seat belt 4 is a large vehicle generated in the above-described emergency. A deceleration sensing means that operates by sensing deceleration, 11 is a locking mechanism that is actuated by the deceleration sensing means 10 to prevent rotation of at least the spool 9 in the belt drawing direction, and 12 is an axial center of the spool 9. A torsion bar (corresponding to the first energy absorbing member of the present invention) 13 which is loosely fitted and penetrated and which rotationally connects the spool 9 and the lock mechanism 11 is provided via the bush 15 by the spring force of the spiral spring 14. Spring means for constantly urging the spool 9 in the belt winding direction, 16 is a pretensioner that operates in the above-described emergency and generates belt winding torque, and 17 is a pretensioner. The seat belt winding torque of Yona 16 is a bush which transmits the spool 9.

The lock mechanism 11 includes a locking base (corresponding to the locking member of the present invention) 20 that can rotate integrally with the first torque transmission portion 18 of the torsion bar 12 and that holds the pawl 19 so as to be able to swing. The torsion bar 12 normally rotates together with the torsion bar 12 and stops in response to the operation of the deceleration sensing means 10 in an emergency. A lock gear 11a is provided that engages with the inner teeth 21 on the side wall to prevent the rotation of the locking base 20, that is, the spool 9, in the seat belt pull-out direction. A male screw shaft portion 22 projects from the main body portion 20 a of the locking base 20, and a stopper 23 that rotates integrally with the spool 9 and has a female screw is screwed into the male screw shaft portion 22.

Further, the second torque transmission portion 24 of the torsion bar 12 is rotatable integrally with the spool 9. Further, energy absorbing pins 25 are projected from male screw shaft portions 22 of a predetermined number of locking bases 20. Further, the cutter 26 is provided integrally with the stopper 23, and the cutter 26 is in contact with the energy absorbing pin 25 at the normal time.

In the conventional seat belt retractor 1 configured as described above, when the seat belt 4 is not attached, the spool 9 is caused to be the bush 15, the torsion bar 12, and the second torque transmission portion of the torsion bar 12 by the spring force of the spring means 13. 24 and the bush 17 are always urged in the seat belt winding direction, so that the seat belt 4 is wound up all of the rewoundable amount.

When the seat belt 4 is pulled out at a normal speed for wearing the seat belt, the spool 9 rotates in the seat belt pulling direction, and the seat belt 4 is pulled out smoothly. After the tongue 6 slidably provided on the seat belt 4 is inserted and locked to the buckle 7, the excessively pulled out seat belt 4 is wound around the spool 9 by the urging force of the spring means 13. It is fitted to the extent that it does not give the passengers a feeling of pressure.

In the above-described emergency, the seat belt winding torque generated by the operation of the pretensioner 16 is transmitted to the spool 9 via the bush 17, and the spool 9 winds up the seat belt 4 by a predetermined amount and firmly restrains the passenger. On the other hand, the deceleration sensing means 10 is activated and the lock mechanism 11 is activated by a large vehicle deceleration generated in an emergency. That is, the operation of the deceleration sensing means 10 prevents rotation of the lock gear 11a in the seat belt pull-out direction, and the pawl 19 of the lock mechanism 11 rotates and engages with the internal teeth 21 on the side wall of the frame 8. Then, since the rotation of the locking base 20 in the seat belt withdrawing direction is locked, only the spool 9 rotates relative to the locking base 20 in the seat belt withdrawing direction. Due to the rotation lock of the locking base 20 in the seat belt withdrawing direction, a load is applied to the seat belt 4 as shown in FIG. 14A, and this load increases.

On the other hand, due to the relative rotation of the spool 9 and the locking base 20, the torsion bar 12 starts torsional deformation, and at the same time, the stopper 23 screwed into the male screw shaft 22 moves toward the main body 20 a of the locking base 20. The energy absorbing pin 25 is pressed through the cutter 26, and the energy absorbing pin 25 starts shearing deformation. Therefore, the load applied to the seat belt 4 increases, and when the torsional deformation of the torsion bar 12 and the shearing deformation of the energy absorbing pin 25 shown in FIG. Lessen increased and limited to this load. That is, the load limiting operation (EA operation) of the seat belt 4 is performed by the torsion bar 12 and the energy absorption pin 25. Thereafter, the spool 9 rotates in the seat belt withdrawing direction while twisting the torsion bar 12 and shearing the energy absorbing pin 25.

When the energy absorbing pin 25 is sheared and broken due to further relative rotation between the spool 9 and the locking base 20, the EA operation due to the shear deformation of the energy absorbing pin 25 is terminated, and thereafter only the EA operation due to the torsional deformation of the torsion bar 12 is performed. Done. That is, the load of the seat belt 4 is a load when only the torsional deformation of the torsion bar 12 shown in FIG.

Then, when the stopper 23 comes into contact with the locking base 20, further rotation of the stopper 23 is prevented, so that the rotation of the spool 9 is also locked and the torsional deformation of the torsion bar 12 is completed. That is, the EA operation by the torsion bar 12 ends. Thereafter, the load of the seat belt 4 is not limited, and the load of the seat belt 4 rapidly rises as shown in FIG. 14A due to the inertial force of the occupant. In this way, the load on the seat belt 4 is limited by the two EA members in the initial operation of the lock mechanism 11 in an emergency, and the load on the occupant from the seat belt 4 is finely relaxed, while the occupant is firmly restrained by the seat belt 4. Is done. Further, when the stopper 23 abuts against the locking base 20, the torsional deformation of the torsion bar 12 is restricted, and the torsion bar 12 is prevented from being cut by the torsional deformation.

In addition, one end of the torsion pipe is connected to the spool and the other end of the torsion pipe is connected to the locking base while a cylindrical (annular) torsion pipe as another energy absorbing member is loosely fitted to the torsion bar. A seat belt retractor that performs EA operation is proposed by the torsion pipe starting torsional deformation simultaneously with the start of torsional deformation of the torsion bar at the time of relative rotation between the spool and the locking base due to the operation of the locking mechanism in the above emergency. (For example, refer to Patent Document 2).

In the seat belt retractor described in Patent Document 2, in the initial stage of the operation of the lock mechanism, as shown in FIG. 14B, the EA operation is performed by the torsional deformation of the torsion bar and the torsional deformation of the torsion pipe. Also, when the torsion pipe is torsionally deformed by a predetermined amount, the other end of the torsion pipe is detached from the locking base, and the EA operation due to the torsional deformation of the torsion pipe is quickly completed. Thereafter, the EA operation only by the torsional deformation of the torsion bar is performed. Is called. Therefore, in the seat belt retractor described in Patent Document 2, similarly to the seat belt retractor described in Patent Document 1, the load of the seat belt is limited at the initial stage of the operation of the locking mechanism in an emergency, so that the seat belt retractor The passenger is firmly restrained by the seat belt while the load on the vehicle is eased. Further, the seat belt retractor described in Patent Document 2 also includes a stopper similar to the stopper 23 described in Patent Document 1, and the torsional deformation of the torsion bar ends when this stopper abuts against the locking base. Cutting due to torsional deformation of the bar is prevented.

Further, when the relative rotation between the spool and the locking base by the operation of the locking mechanism in the above-described emergency is performed, when the relative rotation between the spool and the locking base reaches a predetermined amount from the start of the torsional deformation of the torsion bar, another energy absorbing member The seat belt retractor is proposed in which the EA operation is performed by the operation of the other energy absorbing member and the EA operation is performed only by the torsional deformation of the torsion bar after the operation of the other energy absorbing member is completed. (For example, refer to Patent Document 3).

In each of the seat belt retractors described in Patent Documents 1 to 3, the EA operation by the other energy absorbing member is started simultaneously with the start of the EA operation by the torsion bar during the operation of the locking mechanism in an emergency, and other energy absorption is performed. After the end of the EA operation by the member, only the EA operation by the torsion bar is performed, or after the start of the EA operation by the torsion bar, the EA operation by another energy absorbing member is started and after the end of the EA operation by the other energy absorbing member Only EA operation by the bar is performed.

JP-A-2005-35517. JP 2002-356141 A. JP 2001-106025 A.

Incidentally, in the seat belt retractors described in Patent Documents 1 to 3, the load of the seat belt 4 that suddenly rises at the end of the EA operation by the torsion bar by the stopper is not considered. Therefore, it is desirable to absorb and reduce the load received by the occupant due to the sudden rise of the seat belt load at the end of the EA operation by such a torsion bar. In particular, in the vehicle seat 2 that can absorb the kinetic energy of the occupant by an airbag such as a front seat, the absorption reduction of the load due to this sudden increase in the seat belt load is not required so strongly. In the vehicle seat 2 that cannot absorb the kinetic energy of the occupant due to the above, it is strongly required to reduce the load absorption due to this sudden increase in the seat belt load.

The present invention has been made in view of such circumstances, and the object thereof is to effectively absorb and relax the load received by the occupant with a simple structure at the end of the energy absorbing operation of the energy absorbing member by the stopper. It is an object of the present invention to provide a seat belt retractor that can be used and a seat belt device using the same.

In order to solve the above-described problems, a seat belt retractor according to the present invention includes a spool that is rotatably provided and winds up a seat belt, and rotates in the normal direction along with the rotation of the spool and rotates in the seat belt withdrawal direction in an emergency. A locking mechanism having a locking member to be locked, and the seat is provided between the spool and the locking member, and starts operation when the spool rotates relative to the locking member in a seat belt withdrawing direction. A first energy absorbing member for limiting a load on the belt, and locking the relative rotation of the spool in the seat belt withdrawing direction relative to the locking member when the spool is rotated by a first predetermined amount in the seat belt withdrawing direction. Load limiting operation of the seat belt by the first energy absorbing member A stopper for terminating the operation, and when the spool rotates relative to the second predetermined amount smaller than the first predetermined amount in the seat belt withdrawing direction, the operation is started and the load of the seat belt is limited. And at least a second energy absorbing member that terminates the seat belt load limiting operation when the seat belt load limiting operation of the first energy absorbing member is terminated.

In the seat belt retractor according to the present invention, the first energy absorbing member is a torsion bar that is torsionally deformed when the spool rotates relative to the locking member in the seat belt pull-out direction. Yes.

Further, in the seat belt retractor according to the present invention, the locking member includes a main body portion and a screw shaft portion protruding from the main body portion and provided with a locking member-side screw portion, and the stopper includes the locking member. A stopper-side threaded portion that is screwed into the member-side threaded portion and moves the stopper toward the main body portion of the locking member when the spool rotates relative to the locking member in the seat belt pull-out direction; The energy absorbing member No. 2 is an energy absorbing member that starts a load limiting operation of the seat belt by the movement of the stopper when the spool rotates relative to the seat belt in a first predetermined amount. .

In the seat belt retractor according to the present invention, when the second energy absorbing member is rotated relative to the main body portion of the locking member when the spool rotates relative to the seat belt in a first predetermined amount. It is an energy absorbing member that performs a load limiting operation of the seat belt by being pinched and crushed therebetween.

Further, the seat belt retractor according to the present invention is characterized in that the energy absorbing member to be crushed is an annular energy absorbing member fitted to the screw shaft portion of the locking member so as to be movable in the axial direction. Yes.

Further, in the seat belt retractor according to the present invention, the second energy absorbing member is provided on the screw shaft portion of the locking member adjacent to the body portion side of the locking member of the locking member side screw portion. The spool is a fragile portion that performs load limiting operation of the seat belt by being deformed by the stopper when the spool rotates relative to the seat belt in a first predetermined amount.
Furthermore, the seat belt retractor according to the present invention is characterized in that the fragile portion is an incomplete screw portion provided in a screw shaft portion of the locking member.

Further, in the seat belt retractor according to the present invention, the stopper has an engagement protrusion, and the spool is engaged with the engagement protrusion of the stopper to connect the spool to the stopper in the rotation direction. The second energy absorbing member is provided in the engaging projection of the stopper or the engaging concave groove of the spool, and the spool is moved by a first predetermined amount relative to the seat belt withdrawing direction. It is an energy absorbing member that, when rotated, is squeezed between the stopper and the spool and is crushed to perform a load limiting operation of the seat belt.

In the seat belt retractor according to the present invention, the upstream side wall of the engagement protrusion of the stopper in the seat belt withdrawing direction is inclined at a predetermined inclination angle in the seat belt withdrawing direction from the inside toward the outside. It is characterized by being a tapered portion.

On the other hand, the seat belt device according to the present invention includes a seat belt retractor that winds up the seat belt, a tongue that is slidably supported by the seat belt pulled out from the seat belt retractor, and the tongue is detachable. In the seat belt device that includes at least a buckle to be joined and restrains an occupant by the seat belt, the seat belt retractor is any one of the seat belt retractors of the present invention described above.

According to the seat belt retractor of the present invention configured as described above, the first energy absorbing member that starts operation and limits the load of the seat belt when the spool rotates relative to the locking member in the seat belt pull-out direction. And a stopper that locks the relative rotation of the spool in the seat belt withdrawing direction relative to the locking member when the spool rotates relative to the seat belt in the first predetermined amount, and ends the EA operation by the first energy absorbing member; When the spool rotates relative to the second predetermined amount smaller than the first predetermined amount in the seat belt withdrawing direction, the operation starts to limit the load of the seat belt, and the EA of the seat belt of the first energy absorbing member is limited by the stopper. And a second energy absorbing member that terminates the EA operation when the operation is terminated. To have. Therefore, the EA operation of the second energy absorbing member can be started immediately before the stopper ends the EA operation of the first energy absorbing member. Thereby, after increasing gradually by EA operation | movement of the 2nd energy absorption member, the load of a seatbelt can be made into the load which stood | started up rapidly from the end of EA operation | movement of a 1st energy absorption member. Therefore, the rapid rise of the seat belt load at the end of the EA operation of the first energy absorbing member can be suppressed, and the load received by the occupant can be finely absorbed and relaxed according to the emergency situation.

In particular, as the first energy absorbing member, an energy absorbing structure by the first energy absorbing member is used by using a conventionally known torsion bar that twists and deforms when the spool rotates relative to the locking member in the seat belt withdrawing direction. Can be easy. Therefore, when the EA operation of the first energy absorbing member by the stopper is finished, it is possible to effectively absorb and relax the load received by the occupant with a simple structure.

Further, as the second energy absorbing member, the second energy absorbing member is used by starting the EA operation by moving the stopper when the spool rotates relative to the seat belt in the second predetermined amount. The energy absorption structure by can be further simplified. Therefore, when the EA operation of the first energy absorbing member by the stopper ends, it is possible to effectively absorb and relax the load received by the occupant with a simpler structure.

Further, when the spool rotates relative to the seat belt in a second predetermined amount, the second energy absorbing member is crushed by being squeezed between the stopper and the main body of the locking member, thereby absorbing the second energy. The energy absorption structure by the member can be further simplified. Therefore, when the EA operation of the first energy absorbing member by the stopper ends, it is possible to effectively absorb and relax the load received by the occupant with a simpler structure.

Further, the second energy absorbing member is constituted by a fragile portion provided on the locking member, and when the spool is rotated by a second predetermined amount in the seat belt drawing direction, the fragile portion is deformed by a moving stopper. Further, the energy absorbing structure by the second energy absorbing member can be further simplified. Therefore, when the EA operation of the first energy absorbing member by the stopper ends, it is possible to effectively absorb and reduce the load received by the occupant with a simpler structure.

Furthermore, the engaging protrusion is provided on the stopper, and the engaging groove is fitted to the spool to connect the spool to the stopper in the rotational direction. The spool is used as the second energy absorbing member. An energy absorbing member that performs an EA operation by being crushed by being compressed between the stopper and the spool when the second predetermined amount of relative rotation in the pulling direction is performed. The absorption structure can be further simplified. Therefore, when the EA operation of the first energy absorbing member by the stopper ends, it is possible to effectively absorb and reduce the load received by the occupant with a simpler structure.

On the other hand, according to the seat belt device using the seat belt retractor of the present invention, it is possible to suppress a sudden rise in the seat belt load at the end of the seat belt load limit by the first energy absorbing member. It becomes possible to restrain more finely according to the emergency situation.

These are side views which show roughly the 1st example of embodiment of the seatbelt retractor concerning this invention. FIG. 2 is a longitudinal sectional view taken along line II-II in FIG. These are the exploded perspective views showing the energy absorption part of the seat belt retractor of the 1st example. These are the elements on larger scale of the arrangement | positioning location of the stopper in the seatbelt retractor shown in FIG. (A) thru | or FIG.5 (C) is a figure explaining the action | operation of the energy absorption part of the seatbelt retractor of a 1st example. These are the diagrams which show the load (energy absorption characteristic) of the seatbelt of this invention. These are partial expanded sectional views which show the 2nd example of embodiment of the seatbelt retractor of this invention. (A) thru | or FIG.8 (C) are the figures explaining the action | operation of the energy absorption part of the seatbelt retractor of a 2nd example. FIGS. 9A and 9B are partially enlarged cross-sectional views showing a third example of the embodiment of the seat belt retractor of the present invention. 9A is a cross-sectional view taken along line XA-XA in FIG. 9A, and FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. 9B. (A) thru | or FIG.11 (C) is a figure explaining the action | operation of the energy absorption part of the seatbelt retractor of a 3rd example. These are figures which show typically the conventional common seatbelt apparatus. These are the longitudinal cross-sectional views of an example of the conventional seatbelt retractor which has a stopper. (A) is a diagram showing the load (energy absorption characteristics) of the seat belt of the seat belt retractor described in Patent Document 1, and FIG. 14 (B) is the load (energy absorption characteristics) of the seat belt of the seat belt retractor described in Patent Document 2. FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a side view schematically showing a first example of an embodiment of a seat belt retractor according to the present invention, FIG. 2 is a longitudinal sectional view taken along line II-II in FIG. 1, and FIG. FIG. 4 is an exploded perspective view showing the energy absorbing portion of the seat belt retractor, and FIG. 4 is a partially enlarged view of the location of the stopper in the seat belt retractor shown in FIG. The same components as those in the conventional example shown in FIGS. 12 and 13 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

The basic configuration and basic operation of the seat belt retractor 3 of the first example are the same as those of the seat belt retractor described in Patent Document 1 described above. Therefore, detailed description of their basic configuration and basic operation can be easily understood with reference to Patent Document 1, and will be omitted. Here, Patent Document 1 of the seat belt retractor 3 of the first example is omitted. The structure and operation of parts different from the seat belt retractor described in 1 will be described in detail.

As shown in FIGS. 1 to 4, in the seat belt retractor 3 of the first example, the spool 9 and the male threaded portion 22a of the male threaded shaft portion 22 of the locking base 20 are connected to the spool 9 and the conventional seat belt retractor 3 shown in FIG. A stopper 23 having a female screw 23a and screwed together is screwed together. Further, in the seat belt retractor 3 of the first example, the annular energy absorbing member 27 (corresponding to the second energy absorbing member of the present invention) made of a material that can be crushed (compressed and deformed) such as a resin is the male screw shaft portion 22. Is fitted. In that case, the EA member 27 is provided between the main body portion 20 a of the locking base 20 and the stopper 23 so as to be movable in the axial direction of the male screw shaft portion 22. The EA member 27 is crushed by the moving stopper 23.

The EA member 27 can be provided so as to be rotatable or non-rotatable, but is movable at least in the axial direction. In normal times, the EA member 27 is freely movable between the main body 20 a of the locking base 20 and the stopper 23. In the illustrated example, the EA member 27 is in contact with the stopper 23 at a normal time and is separated from the main body 20a of the locking base 20 with a predetermined gap. However, the EA member 27 may be in contact with the main body 20a of the locking base 20 at a normal time, and may be positioned at an intermediate position between the stopper 23 and the main body 20a of the locking base 20. In the following description, it is assumed that the stopper 23 and the EA member 27 are in the state shown in FIG. 5A during normal times (when the lock mechanism 11 is not operated).
Other configurations of the seat belt retractor 3 of the first example are substantially the same as those of the conventional seat belt retractor 3 shown in FIG. 13 except for the energy absorbing pins 25 and the cutter 26.

In the seat belt retractor 3 of the first example configured as described above, when the above emergency occurs when the stopper 23 and the EA member 27 are in the normal state shown in FIG. Similar to the seat belt retractor 3 in the example shown, the lock mechanism 11 is activated to lock the rotation of the locking base 20 in the seat belt withdrawing direction, and the spool 9 rotates relative to the locking base 20 in the seat belt withdrawing direction. To do. Then, the torsion bar 12 is torsionally deformed to start the EA operation, and at the same time, the stopper 23 starts to move toward the main body 20a of the locking base 20. The movement of the stopper 23 causes the EA member 27 to be pressed by the stopper 23, so that the EA member 27 moves together with the stopper 23 toward the main body 20 a of the locking base 20.

Since the EA member 27 moves freely when it moves, it is not crushed by the pressure from the stopper 23. Therefore, the EA operation is performed only by the torsional deformation of the torsion bar 12. That is, as shown in FIG. 6, the load on the seat belt 4 is limited only by the torsional deformation of the torsion bar 12.

When the spool 9 rotates relative to the seat belt withdrawing direction α by a predetermined amount (corresponding to the second predetermined amount of the present invention), the stopper 23 and the EA member 27 move toward the main body 20a of the locking base 20 by a predetermined amount. As shown in FIG. 5B, the EA member 27 contacts the main body 20a and does not move any further. That is, the EA member 27 is sandwiched between the stopper 23 and the main body portion 20a. After the contact of the EA member 27 with the main body portion 20a, when the spool 9 further rotates relative to the locking base 20 in the seat belt pull-out direction α, the EA member 27 is pressed against the stopper 23 as shown in FIG. Crush. Thereby, as shown in FIG. 6, the load of the seat belt 4 becomes a load limited by the EA operation by the torsional deformation of the torsion bar 12 and the crushing of the EA member 27. When the spool 9 rotates relative to the seat belt withdrawing direction α by a predetermined amount (corresponding to the first predetermined amount of the present invention) and the movement of the stopper 23 stops, the crushing of the EA member 27 is substantially finished. Thereby, the rotation of the spool 9 is locked, and the EA operation due to the torsional deformation of the torsion bar 12 is stopped. Thus, the EA operation of the torsion bar 12 and the EA operation of the EA member 27 are completed simultaneously or almost simultaneously. Thereafter, the load on the seat belt 4 is not limited as in the seat belt retractor 3 in the example shown in FIG. 13, and the load on the seat belt 4 rises as shown in FIG. 6 due to the inertial force of the occupant.

In this way, in the seat belt retractor 3 of the first example, immediately before the EA operation due to the torsional deformation of the torsion bar 12 is terminated by the stopper 23, the load of the seat belt 4 is torsioned by the EA operation due to the crushing of the EA member 27. After gradually increasing from the seat belt load of only the EA operation of the bar 12, the load suddenly rises from the end of the torsional deformation of the torsion bar 12. Therefore, the increase in the seat belt load when the EA operation is stopped by the torsion bar 12 is alleviated, and the load received by the occupant is absorbed and relaxed.
Other operations of the seat belt retractor 3 of the first example are substantially the same as those of the conventional seat belt retractor 3 shown in FIG. 13 except for the operations of the energy absorbing pin 25 and the cutter 26.

According to the seat belt retractor 3 of the first example, the EA member 27 is disposed between the stopper 23 that ends (limits) the torsional deformation of the torsion bar 12 and the main body 20 of the locking base 20, and the EA The EA operation by the member 27 is started immediately before the EA operation of the torsion bar 12 is ended by the stopper 23. As a result, after the load of the seat belt 4 is gradually increased by the EA operation of the EA member 27, it is possible to make the load rise from the end of the EA operation by the torsion bar 12. Therefore, the rapid rise of the seat belt load at the end of the EA operation by the torsion bar 12 can be suppressed, and the load received by the occupant can be absorbed and relaxed.

In addition, since the annular EA member 27 made of a crushable material such as resin is merely disposed on the male screw shaft portion 22 between the stopper 23 and the main body portion 20a of the locking base 20, the energy absorbing structure Can be easy. Therefore, when the EA operation of the torsion bar 12 by the stopper 23 ends, the load received by the occupant can be absorbed and relaxed finely and effectively according to the emergency situation with a simple structure.

Other functions and effects of the seat belt retractor 3 of the first example are substantially the same as those of the conventional seat belt retractor 3 shown in FIG. 13 except for the functions and effects of the energy absorbing pins 25 and the cutter 26.
The EA member 27 can also be provided integrally with the stopper 23 or the main body portion 20a of the locking base 20.

On the other hand, according to the seat belt device 1 using the seat belt retractor 3 of the first example, it is possible to suppress a sudden rise of the seat belt load at the end of the load limitation of the seat belt 4 by the torsion bar 12, It is possible to restrain the occupant more finely according to the emergency situation.

FIG. 7 is a partially enlarged sectional view similar to FIG. 4 showing a second example of the embodiment of the seat belt retractor of the present invention, and FIGS. 8A to 8C illustrate the operation of the second example. It is a figure similar to FIG. 5 (A) thru | or (C).

As shown in FIG. 7, the seat belt retractor 3 of the second example is not provided with the resin-made annular EA member 27 of the first example. Further, the male threaded portion 22a of the male threaded shaft portion 22 of the first example extends to a position very close to the main body portion 20a so that the EA member 27 can come into contact with the main body portion 20a of the locking base 20 when it freely moves without resistance. The stoppers 23 are provided at a constant pitch that is the same as the female screw portion 23a of the stopper 23. On the other hand, the male threaded portion 22a of the male threaded shaft portion 22 of the second example is provided up to the position indicated by the solid line in FIG. 7 where the EA member 27 cannot contact the main body 20a of the locking base 20 when it freely moves without resistance. It is done. Further, as shown by a dotted line in FIG. 7, the male screw shaft portion 22 of the second example has an incomplete screw portion 28 (a weak portion of the present invention) in which the female screw portion 23a of the stopper 23 having a pitch or the like different from the male screw portion 22a interferes. Is provided adjacent to the male screw portion 22a on the main body portion 20a side. In this case, the incomplete threaded portion 28 is provided to a position very close to the main body portion 20a so as to be able to contact the main body portion 20a of the locking base 20.

Normally, the stopper 23 is at the position shown in FIG. 7, and a male screw portion 22 a having a predetermined length exists on the main body portion 20 a side of the locking base 20 of the stopper 23. Then, after the stopper 23 has moved to the incomplete screw portion 28 when the lock mechanism 11 is operated in an emergency, the incomplete screw portion 28 can be crushed by the further moving stopper 23.
Other configurations of the seat belt retractor 3 of the second example are the same as those of the seat belt retractor 3 of the first example.

In the seat belt retractor 3 of the second example configured as described above, when the above-mentioned emergency occurs when the stopper 23 is in the normal state shown in FIG. 8A, the same as in the above-described first example. At the same time as the torsion bar 12 is torsionally deformed to start the EA operation, the stopper 23 starts to move toward the main body 20 a of the locking base 20. At this time, since the female screw portion 23a of the stopper 23 is screwed with the male screw portion 22a, the stopper 23 moves freely with almost no resistance. Therefore, the EA operation is performed only by the torsional deformation of the torsion bar 12. That is, as shown in FIG. 6, the load on the seat belt 4 is limited only by the EA operation of the torsion bar 12.

When the stopper 23 moves by a predetermined amount toward the main body portion 20a of the locking base 20, as shown in FIG. 8 (B), the stopper 23 is located at the end position on the main body portion 20a side of the male screw portion 22a (the right end position in FIG. 8 (B)). ). At this time, the stopper 23 is located immediately before the EA operation of the torsion bar 12 is terminated. Thereafter, when the spool 9 further rotates relative to the locking base 20 in the seat belt withdrawing direction, the stopper 23 moves while crushing the incomplete thread portion 28. That is, the EA operation is performed by crushing the incomplete screw portion 28 by the stopper 23. As a result, as shown in FIG. 6, the load of the seat belt 4 becomes a load limited by the EA operation of the torsion bar 12 and the EA operation of the incomplete screw portion 28.

As shown in FIG. 8C, when the stopper 23 comes into contact with the main body portion 20a of the locking base 20, the movement of the stopper 23 stops and the crushing of the incomplete screw portion 28 is finished. Thereby, the rotation of the spool 9 is locked, and the EA operation of the torsion bar 12 and the EA operation of the stopper 23 and the incomplete screw portion 28 are finished. Thereafter, the load on the seat belt 4 is not limited as in the seat belt retractor 3 in the example shown in FIG. 13, and the load on the seat belt 4 rises as shown in FIG. 6 due to the inertial force of the occupant.

Thus, in the seat belt retractor 3 of the second example, immediately after the EA operation of the torsion bar 12 is finished by the stopper 23, the load of the seat belt 4 is gradually increased by the EA operation of the incomplete screw portion 28, and then the torsion The load suddenly rises from the end of the EA operation of the bar 12. Therefore, the rapid rise of the seat belt load when the EA operation is stopped by the torsion bar 12 is suppressed, and the load received by the occupant is absorbed and relaxed.
Other operations of the seat belt retractor 3 of the second example are the same as those of the seat belt retractor 3 of the first example.

According to the seat belt retractor 3 of the second example, the incomplete thread portion 28 is provided continuously to the external thread portion 22 a of the external thread shaft portion 22, and the EA operation due to the crushing of the incomplete thread portion 28 is torsioned by the stopper 23. The operation starts immediately before the EA operation of the bar 12 is finished. As a result, after the load of the seat belt 4 is gradually increased by the EA operation of the incomplete screw portion 28, the load that has risen from the end of the EA operation by the torsion bar 12 can be obtained. Therefore, the rapid rise of the seat belt load at the end of the EA operation by the torsion bar 12 can be suppressed, and the load received by the occupant can be absorbed and relaxed.

Further, since only the incomplete screw portion 28 is provided adjacent to the male screw portion 22a of the male screw shaft portion 22, the number of parts can be reduced and the energy absorbing structure can be simplified as compared with the first example. Therefore, when the EA operation of the torsion bar 12 by the stopper 23 is completed, it is possible to effectively absorb and relax the load received by the occupant with a simple structure.
Other functions and effects of the seat belt retractor 3 of the second example are the same as those of the seat belt retractor 3 of the first example. In addition, it can replace with the incomplete thread part 28 as a weak part, and can also form as a part which can be deform | transformed with stoppers 23, such as an uneven | corrugated | grooved part.

9 (A) and 9 (B) show a third example of the embodiment of the seat belt retractor according to the present invention, which is a partially enlarged sectional view similar to FIG. 4, and FIG. 10 (A) is in FIG. 9 (A). FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. 9B, and FIGS. 11A to 11C are diagrams for explaining the operation of the third example. 5 is the same diagram as (A) to (C).

As shown in FIGS. 9A and 9B and FIGS. 10A and 10B, the seat belt retractor 3 of the third example is provided with the resin-made annular EA member 27 of the first example. It is not done. Further, the stopper 23 is configured such that a half portion on the opposite side to the main body portion 20a in the axial direction is configured as a power transmission portion 23b, and a half portion on the main body portion 20a side in the axial direction is configured as an energy absorbing portion 23c. Yes.

Further, the stopper 23 has a pair of engaging projections 23d and 23e provided on the outer periphery thereof. Side walls 23d ₁ and 23e ₁ on the upstream side in the seat belt pull-out direction α of the engaging projections 23d and 23e located in the power transmission portion 23b are tapered portions extending so as to be inclined at a predetermined inclination angle in the radial direction. ing. In this case, the tapers of the side walls 23d ₁ and 23e ₁ are inclined from the upstream side to the downstream side in the seat belt withdrawing direction α as they go from the radially inner side to the outer side. Further, the side walls 23d ₂ and 23e ₂ on the downstream side in the seat belt pull-out direction α of the engaging projections 23d and 23e located at the power transmission portion 23b extend substantially in the radial direction.

On the other hand, the spool 9 is provided with a pair of engaging grooves 9a and 9b having substantially the same cross-sectional shape as the engaging protrusions 23d and 23e. Therefore, these engaging concave grooves 9a and 9b are formed on the side walls 9a ₁ and 9b ₁ on the upstream side in the seat belt pull-out direction α, which are tapered portions having substantially the same inclination angles as the side walls 23d ₁ and 23e ₁ of the stopper 23. And the side walls 9a ₂ and 9b ₂ in the radial direction substantially the same as the side walls 23d ₂ and 23e _{2 of} the stopper 23. The engagement protrusions 23d and 23e are fitted in the corresponding engagement grooves 9a and 9b so as to be detachable in the axial direction with almost no gap. In a state where the engagement protrusions 23d and 23e are fitted in the engagement grooves 9a and 9b, the spool 9 and the stopper 23 are engaged in the rotation direction.

The predetermined area including the engaging protrusions 23d and 23e located on the energy absorbing portion 23c is substantially similar to the predetermined area including the engaging protrusions 23d and 23e positioned on the power transmission portion 23b and has a small size. Is formed. Therefore, the engagement protrusions 23d and 23e located on the energy absorbing portion 23c are also the same as the engagement protrusions 23d and 23e located on the power transmission portion 23b on the rotation downstream side walls 23d ₃ and 23e _{3 in} the seat belt pull-out direction α. Side walls 23d ₄ and 23e ₄ on the upstream side in the seat belt withdrawing direction α are provided.

Furthermore, energy absorbing members 29 and 30 made of a collapsible material such as a resin are joined to a predetermined region including the engaging protrusions 23d and 23e located in the energy absorbing portion 23c. Thus, in the state where the EA members 29 and 30 are joined, the cross-sectional shape of the energy absorbing portion 23c is substantially the same in size and shape as the cross-sectional shape of the power transmission portion 23c. The engaging protrusions 23d and 23e to which the EA members 29 and 30 are joined are also fitted in the engaging concave grooves 9a and 9b of the spool 9 so as to be detachable in the axial direction and with almost no gap. In a state where the engagement protrusions 23d and 23e to which the EA members 29 and 30 are joined are fitted in the engagement grooves 9a and 9b, the spool 9 and the stopper 23 are engaged in the rotation direction.

When the lock mechanism 11 is not normally operated, as shown in FIG. 9A, the stopper 23 is engaged with the engagement grooves 9a and 9b with the engagement protrusions 23d and 23e positioned on the power transmission portion 23b. At the same time, the engaging protrusions 23d and 23e located at the energy absorbing portion 23c are escaped from the engaging grooves 9a and 9b. Therefore, in this normal time, the rotation of the spool 9 is transmitted to the stopper 23, and the stopper 23 rotates integrally with the spool 9.

Further, in the case of the emergency when the lock mechanism 11 is operated, the stopper 23 moves toward the main body 20a of the locking base 20 and contacts the main body 20a in the same manner as in the previous examples. At this time, as shown in FIG. 9B, the stopper 23 has engaging protrusions 23d and 23e located in the energy absorbing portion 23c fitted in the engaging grooves 9a and 9b, and the power transmitting portion 23b. Engagement projections 23d and 23e positioned at the position are adapted to escape from the respective engagement grooves 9a and 9b.
Other configurations of the seat belt retractor 3 of the third example are the same as those of the seat belt retractor 3 of the first example.

In the seat belt retractor 3 of the third example configured as described above, when the above-described emergency occurs with the stopper 23 being in the normal state shown in FIG. 11A, the seat belt retractor 3 of each of the above-described examples. Similarly, the torsion bar 12 starts the EA operation, and at the same time, the stopper 23 starts to move toward the main body 20a of the locking base 20. Thereby, the energy absorption part 23c of the stopper 23 fits in each engagement ditch | groove 9a, 9b. When the stopper 23 further moves toward the main body 20a of the locking base 20, the stopper 23 comes into contact with the main body 20a as shown in FIG. 11B, and the movement of the stopper 23 stops. That is, the rotation of the stopper 23 stops. At this time, the power transmission part 23b of the stopper 23 escapes from the respective engaging grooves 9a, 9b. That is, the rotation of the spool 9 in the seat belt withdrawing direction is not transmitted to the stopper 23 via the power transmission portion 23b, but is transmitted to the stopper 23 only through the energy absorbing portion 23c.

Then, the EA members 29 and 30 stop the rotation of the stopper 23, so that the side walls 9a ₁ and 9b ₁ of the engaging concave grooves 9a and 9b of the spool 9 and the side walls of the engaging projections 23d and 23e in the energy absorbing portion 23c. It is clamped between 23d ₁ and 23e ₁ . When the spool 9 further rotates relative to the locking base 20 in the seat belt withdrawing direction α, the EA members 29 and 30 are moved to the side walls 23d ₁ and 23e of the engaging projections 23d and 23e of the stopper 23 as shown in FIG. Since it is pressed by ₁ , it is crushed and EA operation is performed. As a result, as shown in FIG. 6, the load of the seat belt 4 is limited by the EA operation of the torsion bar 12 and the EA operation of the EA member 27. At this time, since the side walls 23d ₁ and 23e _{1 of} the engaging protrusions 23d and 23e and the side walls 9a ₁ and 9b ₁ of the engaging grooves 9a and 9b are tapered portions as described above, the EA members 29, 30 receives a shearing force and is effectively crushed. When the crushing of the EA members 29 and 30 is substantially finished, the rotation of the spool 9 is prevented. Thereby, the EA operation of the torsion bar 12 and the EA operation of the EA members 29 and 30 are completed. Thereafter, the load on the seat belt 4 is not limited as in the seat belt retractor 3 in the example shown in FIG. 13, and the load on the seat belt 4 rises as shown in FIG. 6 due to the inertial force of the occupant.

In this manner, also in the seat belt retractor 3 of the third example, just before the EA operation due to the torsional deformation of the torsion bar 12 is terminated by the stopper 23, the load of the seat belt 4 is reduced by the EA members 29 and 30 by the EA operation. After the gradual increase, the load rising from the end of the EA operation of the torsion bar 12 can be obtained. Therefore, the rapid rise of the seat belt load when the EA operation is stopped by the torsion bar 12 is suppressed, and the load received by the occupant is absorbed and relaxed.
Other operations of the seat belt retractor 3 of the third example are substantially the same as those of the seat belt retractor 3 of the first example.

According to the seat belt retractor 3 of the third example, the EA members 29 and 30 are disposed on the engaging protrusions 23d and 23e of the stopper 23 that restricts the torsional deformation of the torsion bar 12. The EA members 29 and 30 are crushed between the engaging protrusions 23d and 23e of the stopper 23 and the engaging grooves 9a and 9b of the spool 9 immediately before the EA operation of the torsion bar 12 is finished by the stopper 23. Thus, the EA operation by the EA members 29 and 30 is started. As a result, after the load of the seat belt 4 is gradually increased by the EA operation of the EA members 29 and 30, the load can be increased from the end of the EA operation by the torsion bar 12. Therefore, the rapid rise of the seat belt load at the end of the EA operation by the torsion bar 12 can be suppressed, and the load received by the occupant can be absorbed and relaxed.

Further, since the EA members 29 and 30 made of a crushable material such as resin are only provided on the engaging protrusions 23d and 23e of the stopper 23, the number of parts can be reduced as compared with the first example, and an energy absorbing structure can be provided. Easy to do. Therefore, when the EA operation of the torsion bar 12 by the stopper 23 is completed, it is possible to effectively absorb and relax the load received by the occupant with a simple structure.

Other functions and effects of the seat belt retractor 3 of the third example are the same as those of the seat belt retractor 3 of the first example.
The EA members 29 and 30 can also be provided on the engagement concave grooves 9a and 9b side of the spool 9.

The seat belt retractor 3 of the first to third examples includes the seat belt device 1 shown in FIG. 12 described above, the first EA member such as a torsion bar whose EA operation is terminated by the stopper, and the stopper. As long as the seat belt apparatus 1 uses the seat belt retractor 3 having the second EA member to be operated, the seat belt apparatus 1 can be used for any conventionally known seat belt apparatus 1.

In addition, the seat belt retractor of the present invention starts the EA operation simultaneously with the start of the EA operation by the torsion bar or after the start of the EA operation by the torsion bar, like the seat belt retractors described in the respective patent documents 1 to 3. The present invention can also be applied to a seat belt retractor that includes an EA member (third energy absorbing member) that performs the EA operation only by the torsion bar after the EA operation of the third EA member ends.

Also, other EA members other than the torsion bar can be used as the first EA member. In short, the seat belt retractor and the seat belt device of the present invention can be variously modified within the scope of technical matters described in the claims.

The seatbelt retractor and seatbelt device of the present invention prevents the withdrawal of the seatbelt by locking the rotation of the spool that winds up the seatbelt in an emergency in which a large deceleration greater than a predetermined value is applied to the vehicle, such as in the event of a vehicle collision. In addition, the present invention can be suitably used for a seat belt retractor and a seat belt apparatus having an energy absorbing member that restricts the load of the seat belt when the spool is locked.

Claims (10)

1. A spool that is rotatably provided and winds up the seat belt;
   A locking mechanism having a locking member that rotates with the rotation of the spool at a normal time and that locks the rotation in the seat belt withdrawing direction in an emergency;
   A first energy absorbing member that is provided between the spool and the locking member and starts operation when the spool rotates relative to the locking member in the seat belt pull-out direction to limit the load of the seat belt. When,
   When the spool rotates relative to the seat belt in the first predetermined amount, the relative rotation of the spool in the seat belt pull-out direction with respect to the locking member is locked to limit the load on the seat belt by the first energy absorbing member. A stopper that terminates the operation,
   The spool starts operation when the spool rotates relative to the seat belt withdrawing the second predetermined amount smaller than the first predetermined amount to limit the load of the seat belt, and the first energy absorbing member by the stopper. A second energy absorbing member that terminates the seat belt load limiting operation when the seat belt load limiting operation is terminated;
   A seat belt retractor comprising:
2. The seat belt retractor according to claim 1, wherein the first energy absorbing member is a torsion bar that is torsionally deformed when the spool rotates relative to the locking member in the seat belt withdrawing direction.
3. The locking member has a main body portion and a screw shaft portion protruding from the main body portion and provided with a locking member side screw portion,
   The stopper is screwed into the locking member side screw portion and moves the stopper toward the locking member toward the body portion when the spool rotates relative to the locking member in the seat belt pull-out direction. Have
   The second energy absorbing member is an energy absorbing member that starts a load limiting operation of the seat belt by the movement of the stopper when the spool is relatively rotated by a first predetermined amount in the seat belt withdrawing direction. The seat belt retractor according to claim 1 or 2.
4. The second energy absorbing member is crushed by being pinched between the stopper and the main body of the locking member when the spool rotates relative to the seat belt in the first predetermined amount. The seat belt retractor according to claim 3, wherein the seat belt retractor is an energy absorbing member that performs a load limiting operation of the seat belt.
5. The seat belt retractor according to claim 4, wherein the energy absorbing member to be crushed is an annular energy absorbing member fitted to the screw shaft portion of the locking member so as to be movable in the axial direction.
6. The second energy absorbing member is provided on the screw shaft portion of the locking member adjacent to the main body portion side of the locking member of the locking member side screw portion, and the spool is first in the seat belt withdrawing direction. The seat belt retractor according to claim 3, wherein the seat belt retractor is a fragile portion that performs a load limiting operation of the seat belt by being deformed by the stopper when a predetermined amount of relative rotation is performed.
7. The seat belt retractor according to claim 6, wherein the fragile portion is an incomplete screw portion provided in a screw shaft portion of the locking member.
8. The stopper has an engaging projection;
   The spool has an engaging groove that engages with the engaging protrusion of the stopper and connects the spool to the stopper in the rotational direction.
   The second energy absorbing member is provided in the engaging protrusion of the stopper or the engaging groove of the spool, and when the spool rotates relative to the seat belt in a first predetermined amount, the stopper The seat belt retractor according to claim 3, wherein the seat belt retractor is an energy absorbing member that performs a load limiting operation of the seat belt by being pinched between the spool and the spool.
9. The side wall on the upstream side of the rotation of the engaging projection of the stopper in the seat belt withdrawing direction is a tapered portion that is inclined at a predetermined inclination angle in the seat belt withdrawing direction from the inside toward the outside. The seat belt retractor according to claim 8.
10. The seat includes at least a seat belt retractor that winds up the seat belt, a tongue that is slidably supported by the seat belt pulled out from the seat belt retractor, and a buckle that is detachably engaged with the tongue. In a seat belt device that restrains an occupant by a belt,
    The seat belt device according to any one of claims 1 to 9, wherein the seat belt retractor is the seat belt retractor.

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