JP3689540B2 - Seat belt retractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a retractor (winding device) for a seat belt device, and more particularly to a seat belt retractor provided with an energy absorbing mechanism using a torsion bar.
[0002]
[Prior art]
Conventionally, a seat belt retractor for safely holding a vehicle occupant or the like in a seat has an emergency lock mechanism that physically locks the retractor by inertial sensing means that reacts to sudden acceleration, collision or deceleration. Various types of emergency lock retractors that effectively and safely restrain passengers are used.
[0003]
As such an emergency lock type retractor, for example, a webbing is used as in the retractor for a seat belt disclosed in Japanese Patent Laid-Open No. 50-79024, Japanese Patent Publication No. 59-21624, and Japanese Utility Model Publication No. 2-45088. An engagement member disposed at one end of a winding shaft to be wound engages with an engaged portion of a retractor base in the event of a vehicle emergency and can prevent rotation of the winding shaft in the webbing pull-out direction. Some have means.
[0004]
On the other hand, in the emergency lock type retractor, when the emergency lock mechanism is activated by the collision and the webbing is prevented from being pulled out, if the impact force due to the collision is extremely large, the tension acting on the webbing is increased with the passage of time after the collision. It increases and causes a rapid deceleration on the occupant's body, and the load on the occupant from the webbing becomes extremely large. Therefore, recently, when the tension acting on the webbing exceeds a predetermined value set in advance, the webbing is extended by a predetermined amount to provide an energy absorption mechanism that absorbs an impact generated on the passenger's body, Various retractors for seat belts that are more reliably protected have been proposed.
[0005]
And as a seatbelt retractor provided with the above energy absorbing mechanism, a substantially cylindrical winding shaft around which webbing is wound, and a central hole of the winding shaft is inserted into one end of the winding shaft. And a torsion bar that is coupled so as not to rotate relative to the locking base and that is coupled to the locking base so that the other end cannot rotate relative to the locking base. An emergency lock means for preventing the winding shaft from rotating in the webbing pull-out direction by blocking, and when the tension acting on the webbing when the emergency lock means is activated exceeds a predetermined value, the torsion bar Various configurations have been proposed in which the collision energy is absorbed by the torsional deformation of the web and the tension acting on the webbing is controlled (Japanese Patent Laid-Open No. 6-156884). Beauty see Publication Nos. 7-47923).
[0006]
As described above, the configuration in which the collision energy is absorbed by the torsional deformation of the torsion rod inserted through the center hole of the winding shaft, for example, the collision energy is absorbed by the plastic deformation of the winding shaft itself or the retractor base. Compared to the configuration, it has a high degree of freedom in design with respect to the amount of energy absorption and webbing feed, and has a feature that the structure is simple and suitable for downsizing of the retractor.
[0007]
[Problems to be solved by the invention]
By the way, the above-mentioned torsion bar, one end of which is coupled so as not to rotate relative to the winding shaft and the other end of which is coupled relative to the locking base so as not to rotate relatively, The length of may change.
Therefore, for example, when the axial length of the torsion bar becomes shorter due to torsional deformation, the locking base coupled to the other end of the torsion bar moves to the take-up shaft side, and the take-up shaft of the locking base is moved. Since the side end surface and the locking base side end surface of the take-up shaft are in strong sliding contact, frictional resistance acts on the torsional deformation of the torsion bar, affecting the energy absorption load due to the torsional deformation of the torsion bar. is there.
[0008]
On the other hand, when the axial length of the torsion bar becomes longer due to torsional deformation, the locking base coupled to the other end of the torsion bar moves to the outside of the retractor base. There is a possibility that the emergency locking means for engaging the locking base with the retractor base is misaligned in the axial direction, and the locking strength is lowered.
[0009]
Stopper means for preventing rotation of the take-up shaft in the webbing pull-out direction when the torsion amount of the torsion bar reaches a predetermined amount is, for example, the end surface on the take-up shaft side of the locking base and the locking base side of the take-up shaft. In the case where a pair of C-shaped guide grooves each carved on the end face and a lock piece slidable along the inner wall surface of these guide grooves, the axial length of the torsion bar If it becomes longer due to torsional deformation, the clearance between the winding shaft side end surface of the locking base and the locking base side end surface of the winding shaft becomes larger, and the axial engagement portion of the lock piece decreases, resulting in reduced strength. In order to prevent this, there is a problem that the guide groove must be deepened and the lock piece must be enlarged.
[0010]
Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a good seatbelt retractor that can prevent an adverse effect due to a change in axial length accompanying torsional deformation of a torsion bar. .
[0011]
[Means for Solving the Problems]
The above object of the present invention is to provide a substantially cylindrical winding shaft around which a webbing is wound, a central hole of the winding shaft, and one end coupled to the winding shaft so as not to rotate relative to the other end. And a torsion bar coupled to the locking base in a relatively non-rotatable manner, and engaging the locking base with the retractor base in the event of a vehicle emergency to prevent the torsion bar from rotating, thereby causing the winding shaft to move in the webbing withdrawal direction. An emergency locking means for preventing rotation, and a seat belt retractor that absorbs an impact generated on a passenger's body due to torsional deformation of the torsion bar when a tension acting on the webbing exceeds a predetermined value when the emergency locking means is operated. Because
Binding portion of the torsion bar and the take-up shaft, or at least one of the coupling portions of the coupling portion between the torsion bar and the locking base, Ri movable relative der in the axial direction of the torsion bar, wherein each in either one of the coupling portion, the torsion bar and the take-up shaft or the locking base and the retractor for a seat belt, wherein the axial direction configuration entirety in Rukoto capable of causing a clearance between the Is achieved.
[0012]
According to the above configuration, even if the axial length of the torsion bar changes due to torsional deformation at the time of energy absorption, at least one of the coupling portions relatively moves in the axial direction of the torsion bar. It is possible to absorb the change in the axial length. Therefore, it is possible to prevent the end surface on the winding shaft side of the locking base and the end surface on the locking base side of the winding shaft from being in strong sliding contact, or the locking base from moving to the outside of the retractor base.
In addition, Preferably, the corner | angular part of the penetration hole by which the said torsion bar was inserted by the coupling | bond part of the said winding shaft is formed in the curved surface form which attached R. FIG.
Preferably, a corner portion of the insertion hole into which the torsion bar is fitted and inserted in the coupling portion of the locking base is formed in a curved surface shape with an R.
According to this configuration, the coupling portion of the torsion bar is not relatively rotatable in the radial direction of the torsion bar with respect to the winding shaft or the locking base, and is relatively displaceable in the axial direction of the torsion bar. This is suitable when the torsion direction is not determined, and uniform torque transmission can be performed without any phase delay or the like in any torsion direction of the torsion bar.
Also, preferably the coupling portion is press-fitted light no looseness in the radial direction, more preferably the lightly press-fitted is performed along the (axial direction of the torsion bar) the thrust direction.
Also, preferably provided on the outer surface of the inner or the torsion bar insertion hole of the coupling portion, out from the corner of the outer surface of the inner or the torsion bar of the insertion hole, there is no backlash in the radial direction during binding, and A rib protrusion is provided at a position that does not cause a phase delay in torque transmission .
According to this configuration, the inner surface of the insertion hole or the outer surface of the torsion bar and the rib projection are wrapped to provide a press-fitting allowance, and light press-fitting with no radial play can be achieved. Further, when twisted in a predetermined direction, the rib protrusion is not crushed by the torsion torque, and the inner surface of the insertion hole and the outer surface of the torsion bar can be in surface contact to transmit the torsion torque. .
Therefore, the connecting portion of the torsion rod has no play in the radial direction with respect to the insertion hole, and there is no phase delay in torque transmission.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a front longitudinal sectional view of a seatbelt retractor 100 according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of a main part of the seatbelt retractor 100 shown in FIG. 1, and FIG. It is a front longitudinal cross-sectional view which shows the state which the torsion bar of the retractor for seatbelts shown in FIG.
[0014]
The seat belt retractor 100 according to the first embodiment is inserted into a bobbin 3 as a substantially cylindrical winding shaft on which a webbing is wound and a central hole of the bobbin 3 so as to be freely rotatable on the retractor base 1. And is integrally coupled to the bobbin 3 on one end side (right side in FIG. 1) and integrally coupled to the disc-shaped locking base 5 on the other end side (left side in FIG. 1). A cylindrical torsion bar 2 and an emergency lock means 300 for preventing the locking base 5 from rotating in the webbing pull-out direction in the event of a vehicle emergency are provided.
[0015]
The retractor base 1 is obtained by press-molding a metal plate so that left and right side plates 1a and 1b rise from both sides of a back plate 1c fixed to a vehicle body, and has a substantially U-shaped cross section. A torsion bar 2 combined with the bobbin 3 is bridged in a rotatable manner at opposing positions 1a and 1b. A known winding spring device (not shown) that constantly biases the bobbin 3 in the webbing winding direction through the torsion bar 2 at one end of the torsion bar 2 inserted through the side plate 1b of the retractor base 1. ) Is equipped.
[0016]
One end side of the torsion bar 2 has a bobbin coupling portion 2a that can be integrally rotated with the bobbin 3, and the other end side has a locking base coupling portion 2b that can be integrally rotated with the locking base 5. doing. Each of these coupling portions 2a and 2b is formed in a hexagonal cross-sectional shape.
The bobbin coupling portion 2a has a hexagonal cross section, and is fitted into a hexagonal insertion hole 40a of a retainer 40 fitted in a hexagonal fitting recess 3a formed on one end side of the bobbin 3. Thus, the bobbin 3 is coupled to one end of the bobbin 3 so as to be integrally rotatable.
[0017]
Further, in the connecting portion 43 between the torsion bar 2 and the retainer 40, the bobbin connecting portion 2a is inserted into the insertion hole 40a of the retainer 40 by light press fitting along the axial direction of the torsion bar 2. The bobbin coupling portion 2a is not relatively rotatable in the radial direction of the torsion bar 2 with respect to the retainer 40, and is relatively displaceable in the axial direction of the torsion bar 2.
[0018]
That is, as shown in FIG. 4, the insertion hole 40a of the retainer 40, which is rotatably supported by the side plate 1b via the bush 41, has a curved shape with a corner portion 40b having a hexagonal cross section and an R. The bobbin coupling portion 2a of the torsion bar 2 is formed in a hexagonal cross section.
Accordingly, the hexagonal apex of the bobbin coupling portion 2a and the R shape of each corner portion 40b of the insertion hole 40a are wrapped to make a press-fitting allowance, and the bobbin coupling portion 2a of the torsion bar 2 is press-fitted into the insertion hole 40a of the retainer 40. To do. As a result, the bobbin coupling portion 2a of the torsion bar 2 is lightly press-fitted with no radial play in the insertion hole 40a.
[0019]
That is, the configuration shown in FIG. 4 is suitable when the twisting direction of the torsion bar 2 is not determined, and uniform torque transmission without causing a phase delay or the like in any twisting direction of the torsion bar 2. It can be performed. The fitting strength in the radial direction between the torsion bar 2 and the retainer 40 is ensured by sufficiently taking the fitting length along the thrust direction.
[0020]
As shown in FIG. 5, the connecting portion 43 between the torsion bar 2 and the retainer 40 is arranged in a thrust direction at a predetermined position slightly deviated from the corner portion 40b on the inner surface of the insertion hole 40a of the retainer 40. It is good also as a structure which provides the rib protrusion 21 of the cross-sectional triangle shape protrudingly provided so that it might extend. In this case, the hexagonal surface of the bobbin coupling portion 2 a of the torsion bar 2 and the rib projection 21 are wrapped to make a press-fitting allowance, and the bobbin coupling portion 2 a of the torsion rod 2 is press-fitted into the insertion hole 40 a of the retainer 40. As a result, the bobbin coupling portion 2a of the torsion bar 2 is lightly press-fitted with no radial play in the insertion hole 40a.
[0021]
The configuration shown in FIG. 5 described above is suitable when the twisting direction of the torsion bar 2 is determined. That is, in the configuration shown in FIG. 5, when the torsion bar 2 is twisted clockwise in FIG. 5, the rib protrusion 21 is not crushed by the torsion torque, and the hexagonal surface of the bobbin coupling portion 2a of the torsion bar 2 and the retainer The inner surface of the 40 insertion holes 40a come into surface contact to transmit torsional torque. Accordingly, the bobbin coupling portion 2a has no radial play relative to the insertion hole 40a, and no phase delay occurs in torque transmission. The rib protrusion 21 may protrude from the outer surface of the bobbin coupling portion 2a of the torsion bar 2.
[0022]
The locking base coupling portion 2b has a hexagonal cross section, and is fitted into the insertion hole 8a having a hexagonal cross section in the cylindrical boss portion 8 projecting from the end surface on the bobbin side of the locking base 5 so that the locking base 5 And are coupled to be rotatable together. In addition, in order to prevent relative rotation of this portion, the boss portion 8 can be provided with curved corner portions and rib protrusions with the same R as in FIGS.
A fitting recess 9 for receiving the boss portion 8 of the locking base 5 is formed at the end of the bobbin 3 on the side of the locking base, and the bobbin 3 rotates relative to the torsion bar 2 via the fitting recess 9. It is pivotally supported.
[0023]
The torsion bar 2 is subjected to a rotational torque of a predetermined value or more between the coupling parts 2a and 2b, and the torsional deformation part 2c formed between the coupling parts 2a and 2b causes torsional deformation. It is an energy absorption mechanism configured to absorb impact energy acting on.
[0024]
In the present invention, various known configurations can be adopted as the specific configuration of the emergency lock means 300 that restrains the rotation of the locking base 5 in the webbing pull-out direction in the event of a vehicle emergency. For example, in the case of the first embodiment, as shown in FIG. 2, a pole 16 having a locking tooth 16 a at the tip is pivotally supported on the support shaft 7 of the locking base 5. Further, on the outer side of the through hole 20 opened in the side plate 1a, an internal tooth ratchet 21 having engagement inner teeth 25 with which the locking teeth 16a can be engaged is provided in parallel.
[0025]
The emergency lock means 300 disposed in the sensor cover 35 engages the engaging teeth 16a of the pawl 16 with the engaging inner teeth 25 of the internal ratchet 21 in the event of a vehicle emergency, so that the locking base 5 It is configured to prevent rotation in the webbing pull-out direction.
[0026]
Next, the operation of the seat belt retractor 100 of the first embodiment will be described.
When the emergency lock means 300 is activated in the event of a vehicle emergency such as a collision, the rotation of the locking base 5 coupled to the other end of the torsion bar 2 in the webbing pull-out direction is prevented. When a rotational torque exceeding a predetermined value acts on one end side of the torsion bar 2 via the bobbin 3 due to the load acting on the webbing, the torsional deformation of the torsion bar 2 starts and the impact energy is absorbed.
[0027]
During this impact energy absorbing operation, the locking base side end of the bobbin 3 rotates relative to the torsion bar 2, but the fitting recess 9 is rotatably supported by the boss 8 of the locking base 5. The bobbin 3 can slide smoothly. Therefore, the energy absorption load that is absorbed when the torsion bar 2 undergoes torsional deformation changes stably according to the torsion angle, and the load on the occupant's body from the webbing is reduced.
[0028]
At this time, if the torsion bar 2 is shortened due to torsional deformation, the torsion bar 2 is relatively displaced to the left in FIG. 3 with respect to the retainer 60 at the connecting portion 43 between the torsion bar 2 and the retainer 60. (Displaced from the state shown in FIG. 1 to the state shown in FIG. 3), and as a result, a gap 46 is formed between the retainer 60 and the retainer 60. As a result, the change in length of the torsion bar 2 due to torsional deformation is absorbed, and the winding shaft side end surface of the locking base 5 and the locking base side end surface of the bobbin 3 do not slide strongly, and the energy absorption load is unstable. Never become.
[0029]
FIG. 6 is a front longitudinal sectional view of a seatbelt retractor 102 according to a second embodiment of the present invention, and FIG. 7 is a state in which the torsion bar of the seatbelt retractor shown in FIG. It is a front longitudinal cross-sectional view which shows.
In the seat belt retractor 102 according to the second embodiment, in the coupling portion 17 between the torsion bar 12 and the locking base 15, the locking base coupling portion 12 b of the torsion bar 12 is connected to the boss portion 18 of the locking base 15. 4 or the same configuration as shown in FIG. 5 is inserted.
[0030]
That is, the locking base coupling portion 12 b of the torsion bar 12 is lightly press-fitted along the axial direction of the torsion bar 12 into the insertion hole 18 a of the boss portion 18, and is relative to the locking base 15 in the radial direction. It cannot be rotated and can be relatively displaced in the thrust direction.
Further, in the torsion bar 12, after the bobbin coupling portion 12a is press-fitted into the insertion hole 60a of the retainer 60, a portion 12d protruding rightward in FIG. 6 from the tip of the retainer 60 is crimped to the retainer 60 side. .
[0031]
Further, the locking base 15 is pressed rightward in FIG. 6 via the plate 45 by the screw member 44 screwed to the left end portion of the torsion bar 12 in FIG. 6 and pressed against the locking base side end surface of the bobbin 13. Yes.
Therefore, the locking base 15, the bobbin 13, the retainer 60, and the torsion bar 12 are integrally coupled so that the screw member 44 and the plate 45 can escape to the left in FIG. 6 only when the torsion bar 12 is extended. It has become.
[0032]
When the torsion bar 12 becomes longer in accordance with the torsional deformation during the impact energy absorbing operation, the torsion bar 12 is increased relative to the locking base 15 at the connecting portion 17 between the torsion bar 12 and the locking base 15. 7 can be displaced relatively to the left (displaced from the state shown in FIG. 6 to the state shown in FIG. 7). As a result, a gap 47 is formed between the rocking base 15 and the rocking base 15. As a result, the change in the length of the torsion bar 12 due to torsional deformation is absorbed, and the engagement between the pole (not shown) pivotally supported by the locking base 15 and the engaging inner teeth 25 of the internal tooth ratchet 21 in the axial direction. There is no deviation.
The fact that the locking base 15 does not interlock with the leftward movement of the screw member 44 and the plate 45 in FIG. 7 mainly depends on the frictional force generated by the engagement between the pawl and the engagement inner teeth 25.
[0033]
Furthermore, since the gap between the locking base 15 and the bobbin 13 can be prevented from expanding, the stopper means 400 that prevents the bobbin 13 from rotating in the webbing pull-out direction when the torsion amount of the torsion bar 12 reaches a predetermined amount or more. For example, a pair of C-shaped guide grooves 50 and 51 formed on the bobbin side end surface of the locking base 15 and the locking base side end surface of the bobbin 13, and sliding along the inner wall surfaces of the guide grooves 50 and 51. In the case where the lock piece 52 is configured, the axial engagement portion of the lock piece 52 can be prevented from decreasing, and the guide grooves 50 and 51 are deepened to prevent the strength from being lowered. There is no need to increase the size of the lock piece 52.
[0034]
Further, according to each of the above embodiments, the bobbin coupling portion 2a of the torsion bar 2 is press-fitted into the insertion hole 40a of the retainer 40 (first embodiment), or the bobbin of the torsion bar 12 to the boss portion 18 of the locking base 15 is used. By making the press-fitting (second embodiment) of the coupling portion 12b light press-fitting along the thrust direction of the configuration as shown in FIG. 4 or FIG. ) Can be reduced.
[0035]
In each of the above embodiments, the coupling portion 43 (first embodiment) between the torsion bar 2 and the retainer 40 or the coupling portion 17 (second embodiment) between the torsion rod 12 and the locking base 15 (second embodiment) is used. Although the relative rotation in the radial direction of 12) is impossible and the relative displacement is possible in the thrust direction of the torsion bar 2 (12), it is not limited to these configurations.
For example, both the connecting part of the torsion bar and the retainer and the connecting part of the torsion bar and the locking base are relatively non-rotatable in the radial direction of the torsion bar and can be relatively displaced in the thrust direction of the torsion bar 12. You may comprise so that it may become.
[0036]
【The invention's effect】
As described above, according to the present invention, even when the axial length of the torsion bar changes due to torsional deformation during energy absorption, at least one coupling portion moves relatively in the axial direction of the torsion bar. The change in the axial length of the torsion bar can be absorbed.
Therefore, it is possible to prevent the winding shaft side end surface of the locking base and the locking base side end surface of the winding shaft from coming into strong sliding contact, or the locking base from moving to the outside of the retractor base.
Therefore, it is possible to provide a good seat belt retractor that can prevent an adverse effect due to a change in the axial length due to torsional deformation of the torsion bar.
[Brief description of the drawings]
FIG. 1 is a front longitudinal sectional view of a seat belt retractor according to a first embodiment of the present invention.
2 is an exploded perspective view of a main part of the seat belt retractor shown in FIG. 1; FIG.
FIG. 3 is a front longitudinal sectional view showing a state in which the torsion bar of the seat belt retractor shown in FIG. 1 is shortened due to torsional deformation.
4 is a cross-sectional view illustrating a configuration example of a coupling portion between a torsion bar and a retainer of the seatbelt retractor illustrated in FIG. 1;
5 is a cross-sectional view showing another configuration example of a connecting portion between a torsion bar and a retainer of the seatbelt retractor shown in FIG. 1; FIG.
FIG. 6 is a front longitudinal sectional view of a seat belt retractor according to a second embodiment of the present invention.
7 is a front longitudinal sectional view showing a state in which the torsion bar of the seatbelt retractor shown in FIG. 6 has become longer due to torsional deformation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Retractor base 2 Torsion bar 2a Bobbin joint part 2b Locking base joint part 3 Bobbin 5 Locking base 40 Retainer 100 Seat belt retractor

Claims (5)

A substantially cylindrical winding shaft around which the webbing is wound and a center hole of the winding shaft are inserted, and one end is coupled to the winding shaft so as not to rotate relative to the other, and the other end cannot be rotated relative to the locking base. And an emergency lock means for preventing rotation of the take-up shaft in the webbing pull-out direction by engaging the locking base with a retractor base and preventing rotation of the torsion bar in a vehicle emergency A retractor for a seat belt that absorbs an impact generated in a body of an occupant due to a torsional deformation of the torsion bar when a tension acting on the webbing exceeds a predetermined value when the emergency locking means is operated,
Binding portion of the torsion bar and the take-up shaft, or at least one of the coupling portions of the coupling portion between the torsion bar and the locking base, Ri movable relative der in the axial direction of the torsion bar, wherein each in either one of the coupling portion, the torsion bar and the take-up shaft or the locking base and the retractor for a seat belt, wherein the axial direction configuration entirety in Rukoto capable of causing a clearance between the . The retractor for a seat belt according to claim 1, wherein a corner portion of an insertion hole into which the torsion bar is fitted and inserted in the coupling portion of the winding shaft is formed in a curved surface shape with an R. The seatbelt retractor according to claim 1 or 2, wherein a corner portion of an insertion hole into which the torsion bar is fitted and inserted in the coupling portion of the locking base is formed in a curved surface shape having an R. . The seatbelt retractor according to claim 2 or 3, wherein the torsion bar is press-fitted by wrapping the corner apex of the coupling part of the torsion bar and the corner of the insertion hole. Provided on the outer surface of the inner or the torsion bar insertion hole of the coupling portion, deviate from the inner surface or corner of the outer surface of the torsion bar of the insertion hole, there is no backlash in the radial direction during coupling and torque transmission phase The retractor for a seat belt according to any one of claims 1 to 4, further comprising a rib protrusion at a position where no delay occurs .

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