JP5339042B2 - Seat belt retractor - Google Patents

Description

  The present invention relates to a seatbelt retractor including an energy absorbing mechanism that relaxes a load that a passenger receives from a webbing during a vehicle collision.

  In a retractor that winds up a webbing, an emergency lock mechanism that physically locks the webbing drawer when a vehicle collides is generally provided. Also, when the impact force due to the collision is large, when the load acting on the webbing exceeds a predetermined value as the passenger moves inertial, a predetermined amount of webbing is allowed to be absorbed to absorb energy. An energy absorption mechanism that reduces the burden on the occupant's chest is provided (see, for example, Patent Document 1).

  As an energy absorption mechanism, a torsion bar is generally used, but in this case, it is determined by the material and shape of the torsion bar, and can only take a value that changes in a constant or stepped manner. A seat belt retractor that can absorb the inertia energy of the occupant more suitably by changing the energy absorption load is proposed.

  In the seatbelt retractor described in Patent Document 1, a torsion bar arranged coaxially with a spindle for winding webbing, and a wire laid between the lock member and the spindle are provided. Is accommodated in the accommodating groove of the spindle, and the tip end side is movably inserted into the accommodating hole of the spindle. The housing hole of the spindle is curved with a predetermined curvature, and a wire is inserted through a predetermined gap.

Therefore, when relative rotation occurs between the lock member and the spindle by pulling out the webbing, energy absorption is started by the torsional resistance of the torsion bar. Then, when the spindle rotates by a predetermined amount, when the wire is pulled out from the accommodation hole of the spindle, it is not handled until there is no gap with the accommodation hole, and then it is handled and absorbs energy. As a result, a sudden load increase immediately after the start of energy absorption is prevented, and the inertial energy of the occupant is suitably absorbed.
JP 2006-205821 A

  By the way, a standard vehicle is equipped with an airbag system for preventing an occupant who has moved by an energy absorption mechanism from colliding with a vehicle interior wall. It bulges to catch the occupant's body and protects the occupant's body. Therefore, it is desired that the energy absorption load not be reduced in a staircase shape immediately before the end of the energy absorption, but gradually be reduced to make the transition as smoothly as possible to the restraint by the airbag system.

  The present invention has been made in view of the above circumstances, and its purpose is to absorb the inertial energy acting on the occupant during a vehicle collision using both the torsion bar and the bending element, and immediately before the end of the energy absorption. An object of the present invention is to provide a seat belt retractor capable of gradually reducing the restraining force of webbing.

The object of the present invention is achieved by the following configurations.
(1) Retractor frame,
A spindle rotatably supported on the retractor frame and wound with a webbing; a lock member rotatably supported on the retractor frame and fixed to the retractor frame in an emergency;
A torsion bar having one axial end coupled to the spindle and the other axial end coupled to the locking member;
A bending element provided between the lock member and the spindle;
A seat belt retractor comprising:
The spindle is provided with a receiving groove for receiving the bending element,
The bending element is formed in a substantially U-shape, and both ends thereof are held by the spindle through the lock member, and the lengths of the both ends are set to be different from each other. the opposite ends seatbelt retractor according to claim Rukoto is set to be pulled out one by one from the receiving groove of.
(2) The seat belt retractor according to (1), wherein the bending element penetrates the lock member at a point-symmetrical position with respect to a center of the lock member.
(3) Retractor frame,
A spindle rotatably supported on the retractor frame and wound with a webbing; a lock member rotatably supported on the retractor frame and fixed to the retractor frame in an emergency;
A torsion bar having one axial end coupled to the spindle and the other axial end coupled to the locking member;
A bending element provided between the lock member and the spindle;
A seat belt retractor comprising:
The bending element is accommodated in an accommodation hole of the spindle;
Tip of the bending element, have a gradually wedge portion having a thickness which decreases toward the distal end side,
A pipe member that is handled together with the bending element when the locking member and the spindle rotate relative to each other on the base side from the wedge-shaped portion of the bending element is extrapolated. A retractor for a seat belt, wherein the seat belt retractor is configured such that the bending element is pulled out from the receiving hole and then the bending element is pulled out from the receiving hole .
(4) The seat belt retractor according to any one of (1) to (3) , wherein the bending element is partially annealed.

According to the seatbelt retractor of the present invention, the torsion bar as the first energy absorbing member is provided between the spindle and the lock member, and the energy is absorbed along with the plastic deformation of the torsion bar. Further, a bending element which is formed in a substantially U-shape and whose both end portions pass through the lock member and is held by the spindle is provided as the second energy absorbing member. The lengths of both end portions are set to be different from each other, and both end portions of the bending element are set so as to be pulled out from the receiving groove one side at a time. For this reason, the energy is absorbed when the bending element is pulled out while being handled with the relative rotation between the spindle and the lock member, but the binding force of the webbing is gradually reduced just before the end of energy absorption. It is possible to smoothly shift to a situation where the airbag is restrained.

Further, according to the seat belt retractor of the present invention, in addition to the torsion bar as the first energy absorbing member, the bending element having a wedge-shaped portion whose thickness gradually decreases toward the distal end side, It is provided as a second energy absorbing member. Furthermore, when the locking member and the spindle rotate relative to each other, the pipe member to be handled with the bending element is extrapolated to the base side from the wedge-shaped portion of the bending element. Thereafter, the bending element is configured to be pulled out from the receiving hole. Even in such a configuration, the binding force of the webbing can be gradually reduced just before the end of energy absorption, and a smooth transition can be made to the situation where the airbag is restrained.

  Hereinafter, the retractor for seatbelts which concerns on each embodiment of this invention is demonstrated in detail with reference to drawings.

(First embodiment)
As shown in FIG. 1, the seat belt retractor 10 of the first embodiment has a retractor frame 11 attached to a vehicle body (not shown), and a pair of side plates 11 a, 11b is provided oppositely. A hole is provided in the center of both side plates 11a and 11b, and a hollow cylindrical spindle 12 around which the webbing W is wound is supported rotatably.

  In FIG. 1, a tread head 13 as a lock member that is rotatably supported by the retractor frame 11 is provided on the right side of the spindle 12, and the webbing W is pulled out on the right side of the tread head 13. A lock mechanism 15 for locking is attached. The lock mechanism 15 can employ various known configurations. When the lock mechanism 15 is activated in an emergency, the teeth of the pole 14 mounted in the tread head 13 are engaged with the internal teeth 11c of the retractor frame 11. And fixed to the retractor frame 11. As a result, the rotation of the tread head 13 is restricted, and the rotation of the spindle 12 in the belt drawing direction is prevented.

  On the left side of the spindle 12, a winding spring device (not shown) for urging the spindle 12 in the winding direction of the webbing W, and the spindle 12 for removing looseness of the webbing W in the event of a collision. A pretensioner mechanism (not shown) that rotates a predetermined amount in the winding direction of the webbing W is attached.

  Inside the spindle 12, the first energy absorbing member is provided coaxially with the spindle 12, and has one axial end 16 a coupled to the spindle 12 and the other axial end 16 b coupled to the tread head 13. A torsion bar 16 is provided. After the emergency lock mechanism 15 is actuated and the spindle 12 is prevented from rotating in the belt pull-out direction, the torsion bar 16 feeds out the belt while absorbing energy when a load exceeding the set value is applied to the belt. Reduce the burden on the chest.

  In addition, a bending element 18 as a second energy absorbing member is provided between the tread head 13 and the spindle 12 and is formed of a wire formed in a substantially U shape as a whole.

  As shown in FIG. 2, the tread head 13 includes a pair of through holes 13 a and 13 b formed along the axial direction at a point-symmetrical position with respect to the central axis 13 c (the center of the lock member) of the tread head 13. A connecting groove 13e formed deeper than the accommodating portion 13d in which the pole 14 is accommodated is provided so as to bypass the central shaft 13c. The storage grooves 12a and 12b provided in the spindle 12 are also point-symmetric with respect to the center of the spindle 12 (that is, the center of the torsion bar 16) corresponding to the pair of through holes 13a and 13b. It is arranged at the position.

  Accordingly, the central portion 18c of the U-shaped bending element 18 is disposed in the connecting groove 13e of the tread head 13, and both end portions 18a and 18b of the bending element 18 pass through the through holes 13a and 13b of the tread head 13, respectively. Then, it is stored in the storage grooves 12 a and 12 b of the spindle 12. Note that the lengths of both end portions 18a and 18b of the bending element 18 are set to be different from each other.

Next, the operation of the seatbelt retractor 10 according to the first embodiment of the present invention will be described.
During normal travel in which the webbing W is used, the spindle 12 can rotate with respect to the retractor frame 11, so that the webbing W having one end fixed to the spindle 12 can be pulled out. The webbing W can be taken up by rotating the spindle 12 by the spring force.

  When the vehicle collides, the collision sensor detects the collision, the control unit (not shown) operates the pretensioner mechanism, rotates the spindle 12 in the webbing winding direction, and removes the webbing fixed to the spindle 12. Get involved. At this time, since the spindle 12 and the tread head 13 rotate integrally, no force acts on the bending element 18. Further, when the locking mechanism 15 is operated by deceleration or a sudden pulling out of the webbing W, the tread head 13 is locked to the retractor frame 11 and the webbing pull-out direction of the spindle 12 via the torsion bar 16 attached to the tread head 13. The rotation of the webbing W is blocked, and the drawing operation of the webbing W is locked.

  When a strong pulling load exceeding the preset value is applied to the webbing W due to the reaction of the occupant, the energy absorbing mechanism is activated, and the tread head 13 fixed to the retractor frame 11 and the spindle 12 rotated by the webbing pull-out The torsion bar 16 provided between them absorbs energy by twisting and softens the impact acting on the occupant.

  Thereby, the tread head 13 and the spindle 12 are relatively rotated by the twist of the torsion bar 16. Therefore, the end portions 18a and 18b of the bending element 18 as the second energy absorbing member are pulled out from the storage grooves 12a and 12b of the spindle 12, and the through holes 13a and 13b of the tread head 13 and the storage groove of the spindle 12 are extracted. It is handled by the communication part (opening edge of the through holes 13a and 13b) between 12a and 12b, and further energy is absorbed.

  Accordingly, the webbing load (energy absorption load) F generated when the energy absorption mechanism is operated increases due to the torsion bar 16 being twisted and the bending element 18 being handled (section A in FIG. 3A). Then, after absorbing a certain amount of energy by twisting the torsion bar 16 and handling the bending element 18 (B section in FIG. 4A), both end portions 18a and 18b of the bending element 18 are accommodated in the receiving grooves 12a of the spindle 12, By pulling out one side from 12b, the webbing load F gradually decreases (section C in FIG. 3A). As a result, compared with the conventional load change shown in FIG. 3B (C section in FIG. 3B), the decrease in the load near the end of the operation of the energy absorbing mechanism is moderated and restrained by the airbag. Can smoothly transition to the situation.

  As described above, according to the seatbelt retractor 10 according to the first embodiment, the torsion bar 16 that is the first energy absorbing member is provided between the spindle 12 and the tread head 13, and the torsion bar 16 Energy is absorbed with plastic deformation. Further, a bending element 18 that is formed in a substantially U-shape and whose both end portions 18a and 18b pass through the tread head 13 and is held by the spindle 12 is provided as a second energy absorbing member. For this reason, energy is absorbed when the bending element 18 is pulled out while being handled with relative rotation between the spindle 12 and the tread head 13, but the binding force of the webbing W is gradually increased just before the end of energy absorption. And can smoothly shift to a situation where the airbag is restrained.

(Second Embodiment)
Next, a seatbelt retractor 10a according to a second embodiment of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent part as 1st Embodiment, and description is abbreviate | omitted or simplified.

  As shown in FIG. 4, in the seatbelt retractor 10a according to the second embodiment, the bending element 21 is formed by bending a wire into a crank shape, and a head portion 21b is provided on the base side. The distal end portion is provided with a wedge-shaped portion 21a whose thickness gradually decreases toward the distal end side. The wedge-shaped portion 21a is formed by crushing the tip end portion of the wire shown in FIG. 6A with a press and cutting the surplus E shown in FIG. 6B. Note that the wedge-shaped portion 21a at the distal end may be formed continuously to the distal end, but the distal end may be thinner than the wedge-shaped portion 21a and have a uniform thickness from the base side as shown in FIG. That is, the distal end portion of the bending element 21 is formed so that the thickness decreases or becomes constant from the base side toward the distal end side.

  Therefore, the tread head 13 is formed with a locking hole 13g that communicates with the through hole 13f and accommodates the head portion 22b, and the spindle 12 has an annular accommodating groove 12c that faces the through hole 13f. Is formed in the end face, and an accommodation hole 12d extending in the axial direction opening in the accommodation groove 12c is formed inside.

  Therefore, the bending element 21 has a head portion 21b accommodated in the locking hole 13g of the tread head 13, a crank-shaped intermediate portion accommodated in the accommodating groove 12c of the spindle 12, and a base portion side penetrating the tread head 13 from the intermediate portion. The front end side of the hole 13f is accommodated in the accommodation hole 12d of the spindle 12 in the hole 13f.

  A pipe member 22 is provided around the bending element 21 on the base side from the wedge-shaped portion 21a. The pipe member 22 may be an existing pipe made of stainless steel or iron, but may be provided by winding a plate-like member around the bending element 21 in a pipe shape.

  In such a bending element 21, the head 21b is locked in the locking hole 13g so as not to come off, so that when the tread head 13 rotates relative to the spindle 12, the bending element 21 is connected to the pipe. Together with the member 22, it is handled by a communication portion (opening edge of the accommodation hole 12 d) between the through hole 13 f of the tread head 13 and the accommodation groove 12 c of the spindle 12 to absorb energy. When the tread head 13 further rotates, the pipe member 22 is first pulled out from the storage hole 12d, and then the bending element 21 is pulled out from the storage hole 12d. At this time, since the wedge-shaped portion 21a is provided at the distal end portion of the bending element 21, it is easy to come off at the distal end portion. For this reason, the generated webbing load F (see FIG. 3A) gradually decreases.

As described above, according to the seatbelt retractor 10a according to the second embodiment, as the first energy absorbing member, in addition to the torsion bar 16 similar to that of the first embodiment, the distal end portion faces the distal end side. A bending element 21 having a wedge-shaped portion 21a whose thickness gradually decreases is provided as a second energy absorbing member. Even in such a configuration, the binding force of the webbing W can be gradually reduced just before the end of energy absorption, and a smooth transition can be made to the situation where the airbag is restrained.
Other configurations and operations are the same as those in the first embodiment.

(Third embodiment)
Next, a seatbelt retractor according to a third embodiment of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent part as 1st and 2nd embodiment, and description is abbreviate | omitted or simplified.

  As shown in FIG. 7A, the bending element 23 of the present embodiment is formed by bending a wire in a crank shape, and a head portion 23b is provided on the base portion side. Annealed.

As shown in FIG. 7 (b), the bending element 23 is sandwiched between a pair of electrodes 30a and 30b at both ends of the section to be annealed, and heated by resistance heat generation by passing a current between the electrodes 30a and 30b. Then, it cools gradually and anneals, This part is cut and the front-end | tip part 23a is formed. By forming in this way, similarly to the second embodiment, the bending element 23 can be easily removed when the annealed tip 23a is pulled out of the housing groove 12c of the spindle 12, and energy absorption is completed. At the moment, the binding force of the webbing W can be gradually reduced.
Other configurations and operations are the same as those of the second embodiment.

  In addition, this invention is not limited to the thing of the said embodiment, An improvement or a deformation | transformation etc. are possible suitably.

  For example, the wedge-shaped portion 21a at the distal end portion of the bending element 21 of the second embodiment and the annealed portion 23a of the distal end portion of the bending element 23 of the third embodiment are formed on both end portions 18a of the bending element 18 of the first embodiment. It may be applied to the configuration. Moreover, the pipe member 22 of 2nd Embodiment may be provided in the intermediate part of the bending element 18 of 1st Embodiment, or the base side of the bending element 23 of 3rd Embodiment.

It is sectional drawing which shows the state which the tread head cut | disconnected the seatbelt retractor of 1st Embodiment of this invention along the II line | wire of FIG. It is the one side side view of the retractor frame where the locking mechanism was removed. (A) is a graph which shows the change of the webbing load in the seatbelt retractor concerning 1st Embodiment of this invention, (b) is a graph which shows the change of the webbing load in the conventional seatbelt retractor. It is sectional drawing which shows the retractor for seatbelts concerning 2nd Embodiment of this invention. It is sectional drawing of the bending element of FIG. It is an enlarged view of the front-end | tip part for demonstrating the process of a bending element, (a) shows the state before a press, (b) shows the state after a press. (A) is a figure which shows the bending element concerning 3rd Embodiment of this invention, (b) is a figure which shows the method of giving partial annealing.

Explanation of symbols

10, 10a Retractor for seat belt 11 Retractor frame 12 Spindle 13 Tread head (lock member)
16 Torsion bar 18, 21, 23 Bending element 18a, 18b Both ends 21a Wedge-shaped part 21b, 23b Head 22 Pipe part 23a Annealed part

Claims (4)

A retractor frame;
A spindle rotatably supported on the retractor frame and wound with a webbing;
A lock member rotatably supported by the retractor frame and fixed to the retractor frame in an emergency;
A torsion bar having one axial end coupled to the spindle and the other axial end coupled to the locking member;
A bending element provided between the lock member and the spindle;
A seat belt retractor comprising:
The spindle is provided with a receiving groove for receiving the bending element,
The bending element is formed in a substantially U-shape, and both ends thereof are held by the spindle through the lock member, and the lengths of the both ends are set to be different from each other. the opposite ends seatbelt retractor according to claim Rukoto is set to be pulled out one by one from the receiving groove of.   The seat belt retractor according to claim 1, wherein the bending element penetrates the lock member at a point-symmetrical position with respect to a center of the lock member. A retractor frame;
A spindle rotatably supported on the retractor frame and wound with a webbing; a lock member rotatably supported on the retractor frame and fixed to the retractor frame in an emergency;
A torsion bar having one axial end coupled to the spindle and the other axial end coupled to the locking member;
A bending element provided between the lock member and the spindle;
A seat belt retractor comprising:
The bending element is accommodated in an accommodation hole of the spindle;
Tip of the bending element, have a gradually wedge portion having a thickness which decreases toward the distal end side,
A pipe member that is handled together with the bending element when the locking member and the spindle rotate relative to each other on the base side from the wedge-shaped portion of the bending element is extrapolated. A retractor for a seat belt, wherein the seat belt retractor is configured such that the bending element is pulled out from the receiving hole and then the bending element is pulled out from the receiving hole . The retractor for a seat belt according to any one of claims 1 to 3 , wherein the bending element is partially annealed.

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