JP2001294125A - Seat belt device provided with retractor for seat belt with energy absorption mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt device provided with a retractor for the seat belt with an energy absorption mechanism capable of reducing a size of the seat belt device and improving safety of an occupant by improving energy absorption performance without sacrificing reduction of a size of the retractor. SOLUTION: A hollow pipe 40 having one end integrally joined with a bobbin 3 together with a rolling shaft 5 and other end relatively rotating with the rolling shaft 5 is covered by the rolling shaft 5, and energy is absorbed in relatively rotating the hollow pipe 40 and the rolling shaft 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt device for restraining an occupant or the like of a vehicle to a seat, and more particularly to a seat belt device provided with a seat belt retractor having an energy absorbing mechanism.

[0002]

2. Description of the Related Art Conventionally, in a seatbelt device for holding a vehicle occupant or the like safely in a seat, generally, a retractor for a seatbelt which winds a webbing so as to be able to be pulled out is used for sudden acceleration, collision or deceleration. An emergency locking retractor is used which has an emergency locking mechanism that physically locks the webbing drawer by responsive inertial sensing means to effectively and safely restrain the occupant.

[0003] Such an emergency lock type retractor is provided at one end of a winding shaft on which webbing is wound, such as a seat belt retractor disclosed in Japanese Patent Publication No. 59-21624. In some cases, the engaging member is provided with a lock means capable of engaging the engaged portion of the retractor base in a vehicle emergency to prevent the winding shaft from rotating in the webbing withdrawing direction.

[0004] In the locking means, a locking mesh portion formed in a winding shaft through-hole of the retractor base through which the winding shaft passes, or an internal gear plate provided in parallel with the winding shaft through-hole. While the formed ratchet teeth are used as the engaged portion, a lock plate or a locking claw that rotates together with the winding shaft is used as the engaging member. Are engaged to prevent rotation of the take-up shaft in the webbing pull-out direction.

[0005] However, when the impact force due to the collision is large, the webbing tension increases with the passage of time after the collision, so that the occupant's body suddenly decelerates and the load applied to the occupant from the webbing increases. . Therefore, when the load acting on the webbing is equal to or greater than a predetermined value set in advance, the webbing is extended by a predetermined amount to provide an energy absorbing mechanism that absorbs an impact generated on the occupant's body, thereby more reliably securing the occupant's body. Various seat belt retractors designed to protect the seat belt have been proposed. A seat belt retractor having such a configuration is described in JP-A-46-7710.
"Especially energy absorbing devices for safety belts" are known.

In the energy absorbing device, a substantially cylindrical bobbin around which the webbing is wound, a center of the bobbin is inserted, and one end is integrally connected to the bobbin, and is rotatably supported by a retractor base. A winding shaft, a locking base integrally connected to the other end of the winding shaft, and a locking base that is engaged with a retractor base in a vehicle emergency to rotate the bobbin in a webbing pull-out direction. An emergency lock means for preventing the webbing from being pulled out when the load in the webbing pull-out direction acting on the bobbin when the emergency lock means is actuated becomes greater than or equal to a predetermined value. Allows rotation and absorbs impact energy.

That is, the winding shaft inserted through the center of the bobbin is a so-called torsion bar (torsion bar), and when the load acting on the bobbin in the webbing pull-out direction exceeds a predetermined value, the torsion bar itself twists around the axis. Then, the webbing is allowed to be pulled out by an amount corresponding to the rotation of the bobbin in the webbing pull-out direction due to the twist, the occupant restraining force by the webbing is relaxed, and the impact acting on the occupant from the webbing is reduced.

[0008]

However, the impact at the time of a collision differs depending on the vehicle structure. Therefore, in order to sufficiently protect the occupant's body, for example, a set load at which the energy absorbing mechanism starts operating (a so-called energy absorbing load, which is actually a webbing tension at which energy absorption starts), It is required that the amount of deformation (actually, the amount of extension of the webbing) at the time of shock absorption be changed in design in accordance with the vehicle structure and the like.

When the webbing is pulled out by the energy absorbing mechanism, the occupant moves in the collision direction accordingly. At that time, in order to prevent the occupant's body from colliding with the vehicle interior wall, etc., in recent vehicles, by bulging between the occupant and the vehicle interior wall, etc. in a vehicle emergency, the occupant's body is received. 2. Description of the Related Art There is a widespread use of an SRS airbag system for protecting an occupant's body and improving occupant safety in cooperation with a seat belt device.

When such an SRS airbag system is provided, it is required to change the characteristics of the energy absorbing mechanism in order to safely and maximize the effect of the SRS airbag system. I have.

For example, in the early stage of the collision before the occupant comes into contact with the inflated airbag, a large energy absorbing load is secured to minimize the movement of the occupant, and in the latter half of the collision when the airbag starts to restrain the occupant. The demand is to lower the energy absorption load and leave the airbag system to protect the occupants.

From the viewpoint of optimizing the energy absorption load according to the difference in the vehicle structure and sharing the role with the SRS airbag system, the energy absorption mechanism has a change in characteristics such as the energy absorption load. It has been required to be flexible and capable of designing.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide an energy absorbing mechanism of a seat belt retractor with an energy absorbing characteristic in which an energy absorbing load changes during operation. It is possible to easily set the energy absorption load higher without sacrificing the compactness of the retractor, to reduce the size of the seatbelt device and improve occupant safety by improving the energy absorption characteristics. An object of the present invention is to provide a seatbelt device provided with a retractable seatbelt retractor having an energy absorbing mechanism.

[0014]

SUMMARY OF THE INVENTION The object of the present invention is to provide a bobbin around which a webbing is wound, and a bobbin inserted through the center of the bobbin and having one end integrally connected to the bobbin to be rotatable on a retractor base. A winding shaft supported by the vehicle, and emergency locking means for preventing rotation of the bobbin in the webbing withdrawal direction in the event of a vehicle emergency, wherein a load in the webbing withdrawal direction acting on the bobbin when the emergency locking means is actuated is predetermined. As described above, a retractor for a seat belt with an energy absorbing mechanism that functions as an energy absorbing mechanism that absorbs impact energy by allowing the bobbin to rotate in the webbing withdrawing direction by causing the winding shaft to undergo torsional deformation. In the seat belt device, one end is integrally connected to the bobbin together with the winding shaft, and the other end is A seat belt with an energy absorbing mechanism, wherein a hollow pipe rotatable relative to the winding shaft is provided on the winding shaft, and absorbs energy when the hollow pipe and the winding shaft rotate relative to each other. This is achieved by a seat belt device provided with a retractor.

As a configuration for absorbing energy during relative rotation between the hollow pipe and the winding shaft, a configuration in which at least one of the hollow pipe and the winding shaft is plastically deformed is exemplified.

According to the above construction, when the load acting on the bobbin in the webbing withdrawal direction exceeds a predetermined value when the emergency locking means is activated, both the winding shaft and the hollow pipe operate as energy absorbing mechanisms. Then, the vehicle absorbs impact energy in a vehicle emergency.

Therefore, the energy absorbing load of the entire retractor is the sum of the energy absorbing load when the winding shaft undergoes torsional plastic deformation and the energy absorbing load due to the hollow pipe. As compared with the conventional one that absorbs energy in the event of a vehicle emergency, the energy absorption load can be increased by the amount absorbed by the hollow pipe, and it is easy to secure a high energy absorption load.

In contrast to the energy absorption area due to the torsional deformation of the winding shaft, the energy absorption area due to the hollow pipe is:
It can be set independently, for example, by setting the energy absorption area by the hollow pipe so as to partially overlap the energy absorption area due to the torsional deformation of the winding shaft,
In a part of the energy absorption region due to the torsional deformation of the winding shaft, a high energy absorption load is secured by the sum of both energy absorption loads, and the torsion of the winding shaft is limited as long as both energy absorption regions do not overlap. It is possible to set a low energy absorption load only by the energy absorption effect due to the deformation, and to provide the energy absorption mechanism of the seat belt retractor with an energy absorption characteristic in which the energy absorption load changes during operation.

Further, the adjustment of the energy absorbing load of the entire retractor can be performed not only by changing the shaft diameter and the material of the winding shaft, but also by adjusting the dimensions of the hollow pipe where the energy is absorbed.
Changes in shape and material are related, and various elements are related.For example, even if the diameter of the winding shaft is not increased or the material is changed, the required energy can be changed by changing the design of the remaining elements. It is also possible to realize an absorbing load. That is, it is possible to easily set the energy absorbing load without sacrificing the compactness of the retractor by reducing the diameter of the winding shaft or the bobbin of the retractor.

When the dimensions and materials of both the winding shaft and the hollow pipe can be changed, the energy absorption load and the energy absorption area are adjusted on both sides so that the difference in vehicle structure can be accommodated. It can easily respond to demands for unique energy characteristics and can flexibly respond to various needs.

Therefore, the energy absorbing performance can be improved without sacrificing the compactness of the retractor by reducing the diameter of the winding shaft or bobbin of the retractor, and the seat belt device can be downsized. Thus, the safety of the occupant can be improved by improving the energy absorption characteristics.

Preferably, the end of the hollow pipe which rotates relative to the winding shaft is plastically deformed when a load acting on the bobbin in the webbing pull-out direction becomes greater than a predetermined value when the emergency locking means is operated. A configuration that absorbs energy can be used.

Further, if the bobbin engaging portion of the hollow pipe is constituted so as to be plastically deformed when the load in the webbing pull-out direction acting on the bobbin when the emergency locking means is actuated becomes greater than a predetermined value, the energy absorption area can be increased or decreased. It can be easily adjusted, and a wider variety of energy absorption characteristics can be formed.

Preferably, the hollow pipe is formed integrally with an end of the winding shaft, which rotates relative to the hollow pipe, in the seat belt device including the seat belt retractor with an energy absorbing mechanism. The pipe engaging portion is engaged with a winding shaft engaging portion provided on the hollow pipe, and when a load in a webbing pull-out direction acting on the bobbin at the time of operating the emergency locking means becomes a predetermined value or more, the winding is performed. It is preferable that at least one of the locking portion of the shaft and the winding shaft engaging portion of the hollow pipe undergoes plastic deformation, thereby permitting relative rotation between the winding shaft and the hollow pipe.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a seatbelt device having a seatbelt retractor with an energy absorbing mechanism according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partially exploded perspective view of a seat belt retractor 1 according to an embodiment of the present invention.
FIG. 3 is a partial exploded perspective view of the exploded perspective view of FIG. 1 as viewed from the opposite side, and FIG. 3 is a sectional view taken along line AA of FIG.

As shown in FIG. 1, the seat belt retractor 1 has a retractor base 10. The retractor base 10 is formed by press-forming a metal plate such that left and right side plates 10a and 10b are raised from both sides of a back plate 10c fixed to a vehicle body and have a substantially U-shaped cross section. The left and right side plates 10a, 10b have through holes 13,
14 are provided. One (left side in the figure) side plate 10a
Internal teeth 13a are formed in the peripheral portion of the through hole 13 at intervals in the circumferential direction. A pretensioner 30 and a take-up spring device 35 are provided on the outside of the side plate 10a (the side opposite to the side facing the other side plate 10b).

The take-up spring device 35 includes a lower case 35a facing the side plate 10a of the retractor base 10, and an upper case 35b combined with the lower case 35a to form a storage space therebetween.

The retractor base 10 has a substantially cylindrical bobbin 3 around which webbing is wound, and a substantially cylindrical bobbin 3 which is inserted through the bobbin 3 and rotatably supported by the side plates 10a and 10b of the retractor base 10. A winding shaft (torsion bar) 5 as an energy absorbing member is attached. The winding shaft 5 serves as a rotation shaft of the bobbin 3.

At one end (the left end in the figure) of the winding shaft 5, a hollow pipe 40 as an energy absorbing member and a sleeve 8 as a connecting member are connected via a hollow pipe 40 so as to be integrally rotatable with the bobbin 3. A bobbin connecting portion 5a is provided, and a locking base connecting portion 5b is provided on the other end side (right end side in the drawing) of the locking base 7 serving as a part of the lock member so as to be integrally rotatable. I have. These connecting portions 5a and 5b have a hexagonal cross section.

The side plates 10a, 1 of the retractor base 10
The leading end portion 5d of the winding shaft 5 bridged between 0b and having the one side plate 10a inserted therein is constantly urged by the winding spring device 35 to rotate the bobbin 3 in the webbing winding direction.

As shown in FIG. 2, the connecting portion 5a of the winding shaft 5
Is a hole 3 having a substantially triangular cross section formed at one end of the bobbin 3.
The hollow pipe 40 is rotatable integrally with the bobbin 3 by being fitted into a hexagonal cross-section insertion hole 8a (see FIG. 1) formed in the sleeve 8 which fits into the sleeve 8 through the end of the hollow pipe 40 having a hexagonal cross section. Is joined to. Also, as shown in FIG.
Is fitted into a hexagonal insertion hole 7d formed in the boss portion 7c of the locking base 7 so that the locking base 7
And are integrally rotatable. Shaft 8 of sleeve 8
b is supported by the take-up spring device 35.

The hollow pipe 40 has a generally hexagonal cross-section, and one end 42 has a substantially circular cross-section with an enlarged diameter. The other end 40 a of the hexagonal cross section is fixed by being interposed between the fixing portion 5 a of the winding shaft 5 and the sleeve 8. The hollow pipe 40 is formed to have a length that extends to a portion in front of the fixed portion 5 b of the winding shaft 5. The end 40b having a substantially circular cross section constitutes a winding shaft engaging portion 40b.
The winding shaft engaging portion 40b has a concave portion 40c formed in a part of the inner peripheral surface, and the peripheral surface partially protrudes in the radial direction corresponding to the concave portion 40c.

The portion 5e of the winding shaft 5 facing the winding shaft engaging portion 40b is a hollow pipe engaging portion 5e. The hollow pipe engaging portion 5e has a substantially cylindrical shape formed to have a slightly smaller diameter than the inner diameter of the winding shaft engaging portion 40b of the hollow pipe 40. On a part of the peripheral surface of the hollow pipe engaging portion 5e, a projection 5f is formed which fits into a concave portion 40c formed in the winding shaft engaging portion 40b of the hollow pipe 40.

The take-up shaft 5 is subjected to a rotational torque greater than a predetermined value between the connecting portions 5a and 5b, and the deforming portion 5c between the connecting portions 5a and 5b is twisted to cause plastic deformation.
The energy absorbing means is configured to absorb impact energy acting on the occupant's body.

Further, the second pipe is configured such that the hollow pipe 40 absorbs the impact energy by rotating relative to the winding shaft 5 so that the winding shaft engaging portion 40b undergoes plastic deformation. Absorption means. For this,
The material, strength, and the like of the hollow pipe 40 are set so that the winding shaft engaging portion 40b is plastically deformed by relative rotation with respect to the winding shaft 5.

The emergency locking means connects the locking base 7 and the retractor base 10 in the event of a vehicle emergency (when sudden deceleration occurs due to an accident or the like, or when the webbing is suddenly pulled out). The rotation of the bobbin 3 in the webbing withdrawing direction is prevented by preventing the base 7 from rotating in the webbing withdrawing direction. Various known structures can be adopted as the specific structure of the emergency locking means.

As shown in FIG. 1, the emergency locking means of this embodiment is a locking member (part of the locking member) rotatably supported by a pin 7a of a locking base 7 and having a locking tooth 9a at its tip. ), And a latch plate 15 provided in parallel with the side plate 10b of the retractor base 10 and formed with internal teeth 15g with which the locking teeth 9a of the first pole 9 can mesh. This emergency locking means connects the locking base 7 and the retractor base 10 by engaging the locking teeth 9a of the first pawl 9 with the internal teeth 15g of the latch plate 15 fixed to the side plate 10b in a vehicle emergency. The rotation of the locking base 7 in the webbing pull-out direction is prevented.

The bobbin 3 is a die-cast product made of aluminum or zinc or the like manufactured by a die-casting method for the purpose of weight reduction or the like. The bobbin 3 includes a substantially cylindrical body 3c around which the webbing is wound, and flanges 3a and 3b for preventing the webbing from being disturbed. The bobbin 3 is provided with a winding shaft through-hole 3h through which the winding shaft 5 passes, along the axis. The bobbin 3 has a lever through hole 3k through which a lever 23 as a transmission member penetrates.
It is provided in parallel with the winding shaft through hole 3h.

As shown in FIG. 1, the lever 23 penetrated through the lever through hole 3k of the bobbin 3 has a shaft portion 23c and a connecting portion having a rectangular cross section formed at one end (the left end in the figure) of the shaft portion 23c. An arm 23b is connected to the other end (right end in the figure) of the shaft 23c and protrudes in the radial direction of the shaft 23c. The coupling portion 23 a having a rectangular cross section is coupled to a rectangular hole of the second pole 25 as a stop means, and is fixed with a screw 27. The arm 23b is disposed on the axial end surface of the bobbin 3 (side surface of the flange 3b).

As shown in FIG. 2, a recess 3 d for storing the second pole 25 is provided on one (left side in the figure) flange portion 3 a of the bobbin 3. The second pole 25 is formed with an internal tooth 42 formed on the side plate 10 a of the retractor base 10.
(See FIG. 1). A tape member 21 is arranged between the locking base 7 and the other flange portion 3b (right side in the figure) of the bobbin 3.

The tape member 21 is an integral injection-molded product made of resin, and includes an annular portion 21a, a tape portion 21t,
And a hook portion 21f. A convex portion 21c is formed on the inner periphery of the annular portion 21a, and the convex portion 21c is formed in a concave portion 7e formed on the outer periphery of the boss portion 7c of the locking base 7.
, The tape member 21 is fixed to the locking base 7. The hook 21f connected to the tip of the tape 21t is locked to the arm 23b of the lever 23.

FIG. 4 is an enlarged view showing the vicinity of the arm 23b of the lever 23. As shown in FIG. 4, the arm portion 23b has a convex (projecting to the near side with respect to the paper surface) outer guiding portion 23 for guiding the hook portion 21f of the tape member.
u and an inner guide portion 23d are formed. Hook part 2
If 1f, the protrusion 21g of the tape portion 21t is
The position is locked and locked by a small projection 23s provided on 3d. The hook portion 21f abuts on the convex portion 3i formed inside the flange portion 3b of the bobbin by being restricted in position by the small protrusion 23s.
The rotation in the clockwise direction in FIG. Therefore, in normal times, the arm 23b does not move and the lever 23 does not rotate.

When a predetermined tensile force is applied to the tape portion 21t, the projection 21g of the tape portion 21 is deformed to get over the small projection 23s of the lever 23, and the hook portion 21f can be moved.

When the hook 21f moves to the stop wall 23e, the lever 23 rotates about the shaft 23c by the tension of the tape 21t. Along with this, the second pole coupled to the other end of the shaft portion 23c rotates, and the side plate 10
By engaging with the internal teeth of a, the rotation of the bobbin is restricted, and further pulling out of the webbing and absorption of impact energy are prevented.

Next, the operation of the seat belt retractor 1 of the first embodiment will be described. When the emergency locking means operates in the event of a vehicle emergency such as a collision, the locking base 7 connected to the other end of the winding shaft 5 is prevented from rotating in the webbing pull-out direction. When a rotation torque equal to or more than a predetermined value acts on one end of the winding shaft 5 via the bobbin 3 due to a load acting on the webbing, the winding shaft 5
Begins to be deformed, and the amount of torsional deformation of the winding shaft 5 is
The impact energy is absorbed by the bobbin 3 rotating in the webbing pull-out direction.

Also, when relative rotation between the winding shaft 5 and the hollow pipe 40 occurs due to the start of the torsional deformation of the winding shaft 5, the projection 5f of the winding shaft 5 engages with the winding shaft of the hollow pipe 40. Due to the load acting on the joining portion 40b, the winding shaft engaging portion 4
The plastic deformation of the winding shaft engaging portion 40b also absorbs the impact energy.

FIG. 5 shows a process of absorbing impact energy by the hollow pipe 40. The arrow in FIG.
Represents the relative rotation direction of the hollow pipe 40 with respect to. FIG.
(A) shows a state in which the hollow pipe 40 and the winding shaft 5 are not relatively rotated. At this time, the projection 5f of the winding shaft 5 fits into the concave portion 40c of the winding shaft engaging portion 40b of the hollow pipe 40. It is in a state of being left. When the hollow pipe 40 and the winding shaft 5 start to rotate relative to each other, the protrusion 5f of the winding shaft 5 expands the diameter of the winding shaft engaging portion 40b of the hollow pipe 40 as shown in FIG. The winding shaft engaging portion 40b is plastically deformed. Then
As shown in (c) to (f), the winding shaft engaging portion 40b of the hollow pipe 40 continues to be plastically deformed until the relative rotation between them becomes one rotation, and during this time, impact energy is absorbed.

Thereafter, when the winding shaft 5 rotates relative to the bobbin 3 by a predetermined amount, the tape member 21 and the lever member 23 are rotated.
The second pawl 25 rotates by the action of, and the second pawl 25 is engaged with the internal teeth of the side plate 10a, whereby the relative rotation between the winding shaft 5 and the bobbin 3 is prevented, and the absorption of the impact energy is completed. .

As described above, when the emergency locking means is activated in the event of a vehicle emergency and the load acting on the bobbin 3 in the webbing withdrawal direction exceeds a predetermined value, both the hollow pipe 40 as the energy absorbing means and the winding shaft 5 are used. Operate as energy absorbing mechanisms to absorb impact energy in the event of a vehicle emergency.

Accordingly, as shown in FIG. 6A, the energy absorption load of the entire retractor is the energy absorption load f1 when the winding shaft 2 undergoes torsional deformation and the energy absorption load of the winding pipe of the hollow pipe 40. The sum f3 of the energy absorption load f2 when the plastic deformation occurs with the joint 40b. For example, as shown in FIG. 6 (b), the winding shaft 5 absorbs energy in the event of a vehicle emergency only by torsional deformation. Compared with the conventional one, the energy absorption load can be increased by the amount absorbed by the hollow pipe 40, and a high energy absorption load can be easily secured.

Further, as shown in FIG.
The energy absorption region A2 due to the plastic deformation of the hollow pipe 40 can be set independently of the energy absorption region A1 due to the torsional deformation of the hollow pipe 40. For example, the hollow pipe 4
By setting the energy absorption region A2 due to the plastic deformation of 0 to part of the energy absorption region A1 due to the torsional deformation of the winding shaft 5, a part of the energy absorption region due to the torsional deformation of the winding shaft 5 is set. Then, a high energy absorption load is secured by the sum of both energy absorption loads.
Also, as long as both energy absorption areas do not overlap,
A low energy absorption load can be set only by the energy absorption effect due to the torsional deformation of the winding shaft 5.
In this way, the energy absorbing mechanism of the seat belt retractor can have an energy absorbing characteristic in which the energy absorbing load changes during operation.

Further, the adjustment of the energy absorbing load of the entire retractor can be achieved not only by changing the shaft diameter and the material of the winding shaft 5 but also by adjusting the portion (the winding shaft engaging portion) where the hollow pipe 40 undergoes plastic deformation. Changes in dimensions, shapes, and materials are also involved, and various elements are involved. For example, even if it is not necessary to increase the diameter of the winding shaft 5 or change the material, it is possible to change the design of the remaining elements. It is also possible to realize a desired energy absorption load. That is, the energy absorption load can be easily set higher without sacrificing the compactness of the retractor by reducing the diameters of the winding shaft 5 and the bobbin 3 of the retractor.

When the dimensions and materials of both the winding shaft 5 and the energy absorbing member 40 can be changed, the adjustment of the energy absorbing load and the adjustment of the energy absorbing area are performed on both, thereby obtaining a difference in the vehicle structure. Therefore, it is possible to easily respond to a request for a unique energy characteristic according to the above-mentioned requirements, and to flexibly respond to various needs.

Therefore, the energy absorption performance can be improved without sacrificing the compactness of the retractor by reducing the diameter of the winding shaft 5 and the bobbin 3 of the retractor.
The size of the seat belt device can be reduced, and the safety of the occupant can be improved by improving the energy absorption characteristics.

Next, another embodiment of the present invention will be described.
The following embodiment is different from the first embodiment in the shape of the winding shaft engaging portion 40b of the hollow pipe. Therefore, only the shape and operation of the winding shaft engaging portion 40b of the hollow pipe 40 will be described. The description of the other components is omitted.

FIG. 7A shows a hollow pipe 1 according to a second embodiment.
FIG. 4 is a cross-sectional view illustrating an engagement state between the winding shaft 40 and a winding shaft 5;
(B) is a graph showing the state of impact energy absorption by this configuration. In addition, in the following graphs, the dotted line represents the impact energy absorption state of the first embodiment. FIG.
The hollow pipe 140 shown in FIG.
b is a shape expanded in diameter over a predetermined length in the circumferential direction,
At the time of assembly, the protrusion 5f of the hollow pipe engaging portion 5e of the winding shaft 5 is connected to the rotationally upstream end of the enlarged diameter portion 140d (see FIG. 7).
(The right end in (a)). The winding shaft engaging portion 140b of the hollow pipe 140 has an enlarged diameter portion 140d formed over a predetermined length in the circumferential direction, and a plastically deformed region is a region excluding the enlarged diameter portion 140d, compared to the first embodiment. Therefore, the plastic deformation region is reduced.
Therefore, as shown in FIG.
The amount of impact energy absorbed by 0 can also be made smaller than in the first embodiment. According to the second embodiment, the enlarged diameter portion 140d
By setting the region to an appropriate length, the amount of impact energy absorption can be set appropriately.

FIG. 8A shows a hollow pipe 2 according to the third embodiment.
FIG. 4 is a cross-sectional view illustrating an engagement state between a take-up shaft and a take-up shaft;
(B) is a graph showing the state of impact energy absorption by this configuration. The hollow pipe 240 shown in FIG.
Has the same shape as that of the second embodiment shown in FIG. That is, in the third embodiment, the hollow pipe 2
It is assembled so that the projection 5f of the hollow pipe engaging portion 5e of the winding shaft 5 is located at the downstream end of the enlarged diameter portion 240d in the rotation direction. Therefore, as shown in FIG. 8B, according to the third embodiment, even when the relative rotation between the hollow pipe 240 and the winding shaft 5 starts, the protrusion 5 f is kept at the enlarged diameter portion 240.
While moving d, impact energy absorption by the hollow pipe 240 is not performed, and the start time of impact energy absorption by the hollow pipe 240 can be made later than in the first embodiment.

FIG. 9A shows a hollow pipe 3 according to the fourth embodiment.
FIG. 4 is a cross-sectional view illustrating an engagement state between a take-up shaft and a take-up shaft;
(B) is a graph showing the state of impact energy absorption by this configuration. In the hollow pipe shown in FIG. 9, the thickness t1 of the winding shaft engaging portion 5e is formed thicker than in the first embodiment. Therefore, as shown in FIG. 9B, according to the fourth embodiment, the plastic deformation load can be increased as compared with the first embodiment without largely changing the shape, and the amount of impact energy absorption can be increased. can do.

FIG. 10A is a sectional view showing an engagement state between the hollow pipe 440 and the winding shaft 5 according to the fifth embodiment.
(B) is a graph showing the state of impact energy absorption by this configuration. The hollow pipe 440 shown in FIG.
The winding shaft engaging portion 440b is formed such that the depth d of the concave portion 440c is deeper than in the first embodiment, and the height h of the projection 5f of the winding shaft 5 is higher than in the first embodiment. Therefore, as shown in FIG. 10B, according to the fifth embodiment, the amount of plastic deformation can be increased as compared with the first embodiment without largely changing the shape, and the amount of impact energy absorption can be increased. can do.

FIG. 11A is a cross-sectional view showing an engagement state between the hollow pipe 540 and the winding shaft 5 according to the sixth embodiment.
(B) is a graph showing the state of impact energy absorption by this configuration. The hollow pipe 540 shown in FIG.
The thickness t2 of the winding shaft engaging portion 540b is formed to be thinner than in the first embodiment. Therefore, as shown in FIG. 11B, according to the sixth embodiment, the plastic deformation load can be reduced as compared with the first embodiment without largely changing the shape, and the amount of impact energy absorption can be reduced. can do.

In each of the above embodiments, the hollow pipe is plastically deformed when the load applied to the bobbin 3 in the webbing pull-out direction exceeds a predetermined value when the emergency locking means is operated. However, instead, a protrusion may be provided on the inner surface of the winding shaft engaging portion, and the hollow pipe engaging portion of the winding shaft may be plastically deformed or scraped. Also, if each of the winding shaft engaging portion of the hollow pipe and the hollow pipe engaging portion of the winding shaft is configured to be plastically deformed, the increase and decrease of the energy absorption range can be easily adjusted, so that more various energy can be obtained. The formation of absorption properties becomes possible.

[0063]

According to the seatbelt device provided with the seatbelt retractor having the energy absorbing mechanism of the present invention, when the load applied to the bobbin in the webbing pull-out direction exceeds a predetermined value when the emergency locking means is operated, the winding is performed. Both the mandrel and the hollow pipe operate as energy absorbing mechanisms, respectively, to absorb impact energy in a vehicle emergency.

Therefore, the energy absorbing load of the entire retractor is the sum of the energy absorbing load when the winding shaft undergoes torsional deformation and the energy absorbing load due to the hollow pipe. As compared with the conventional one that absorbs energy in the event of a vehicle emergency, the energy absorption load can be increased by the amount absorbed by the hollow pipe, and it becomes easy to secure a high energy absorption load.

The energy absorption area due to the torsional deformation of the winding shaft and the energy absorption area due to the hollow pipe can be set independently. For example, the energy absorption area due to the hollow pipe can be changed to the torsional deformation of the winding shaft. By setting so as to overlap a part of the energy absorption region by, in a part of the energy absorption region due to the torsional deformation of the winding shaft,
While ensuring a high energy absorption load by the sum of both energy absorption loads, in the range where both energy absorption regions do not overlap, set a low energy absorption load only by the energy absorption effect due to the torsional deformation of the winding shaft. The energy absorbing mechanism of the seat belt retractor can have an energy absorbing characteristic in which the energy absorbing load changes during operation.

Further, the adjustment of the energy absorbing load of the entire retractor can be performed not only by changing the diameter of the winding shaft and the material, but also by changing the dimensions of the hollow pipe where the energy is absorbed.
Changes in shape and material are related, and various elements are related.For example, even if the diameter of the winding shaft is not increased or the material is changed, the required energy can be changed by changing the design of the remaining elements. It is also possible to realize an absorbing load. That is, the energy absorption load can be easily set higher without sacrificing the compactness of the retractor by reducing the diameter of the winding shaft or the bobbin of the retractor.

When the dimensions and materials of both the winding shaft and the hollow pipe can be changed, the energy absorption load and the energy absorption range are adjusted on both sides to adjust for the difference in vehicle structure and the like. It can easily respond to demands for unique energy characteristics and can flexibly respond to various needs.

Therefore, it is possible to improve the energy absorbing performance without sacrificing the compactness of the retractor by reducing the diameter of the winding shaft and the bobbin of the retractor, and to reduce the size of the seat belt device. Thus, the safety of the occupant can be improved by improving the energy absorption characteristics.

[Brief description of the drawings]

FIG. 1 is a first view of a seat belt retractor with an energy absorbing mechanism used in a seat belt device according to the present invention.
It is an exploded perspective view of an embodiment.

FIG. 2 is an exploded perspective view of a main part of the seat belt retractor shown in FIG.

FIG. 3 shows the seat belt retractor A shown in FIG.
It is -A sectional drawing.

FIG. 4 is an enlarged view of the vicinity of an arm portion of a lever.

FIG. 5 is a longitudinal sectional view showing a state in which the hollow pipe undergoes plastic deformation.

6A is an energy absorption characteristic diagram of the seat belt retractor shown in FIG. 1, and FIG. 6B is an energy absorption characteristic diagram in a case where only a winding shaft is provided as an energy absorption mechanism. .

FIG. 7A is a longitudinal sectional view of a main part of a second embodiment of a seat belt retractor with an energy absorbing mechanism used in a seat belt device according to the present invention, and FIG. It is an energy absorption characteristic diagram.

FIG. 8A is a longitudinal sectional view of a main part of a third embodiment of a seat belt retractor with an energy absorbing mechanism used in a seat belt device according to the present invention, and FIG. It is an energy absorption characteristic diagram.

FIG. 9A is a longitudinal sectional view of a main part of a fourth embodiment of a seatbelt retractor with an energy absorbing mechanism used in the seatbelt device according to the present invention, and FIG. 9B is according to the fourth embodiment; It is an energy absorption characteristic diagram.

FIG. 10A is a longitudinal sectional view of a main part of a fifth embodiment of a seatbelt retractor with an energy absorbing mechanism used in the seatbelt device according to the present invention, and FIG. It is an energy absorption characteristic diagram.

11A is a longitudinal sectional view of a main part of a seat belt retractor with an energy absorbing mechanism used in a seat belt device according to a sixth embodiment of the present invention, and FIG. It is an energy absorption characteristic diagram.

[Explanation of symbols]

Reference Signs List 1 seat belt retractor with energy absorbing mechanism 3 bobbin 5 winding shaft (torsion bar) 5e hollow pipe engaging portion 5f projection 7 locking base 10 retractor base 40, 140, 240, 340, 440, 540 hollow pipe 40b, 140b, 240b, 340b, 440b, 5
40b winding shaft engaging portion 40c recess

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoji Igarashi 12 Kirihara-cho, Fujisawa-shi, Kanagawa Nippon Seiko Co., Ltd. (72) Inventor Takamitsu Kato 12 Kirihara-cho, Fujisawa-shi, Kanagawa Nippon Seiko F Terms (reference) 3D018 DA07 MA03

Claims (1)

[Claims] A bobbin on which a webbing is wound, a winding shaft inserted through the center of the bobbin and one end of which is integrally connected to the bobbin and rotatably supported by a retractor base; Emergency lock means for preventing the bobbin from rotating in the webbing pull-out direction, and when the load in the webbing pull-out direction acting on the bobbin at the time of activation of the emergency lock means becomes a predetermined value or more, the winding shaft is torsionally deformed. A seat belt device including a seat belt retractor with an energy absorbing mechanism that functions as an energy absorbing mechanism that absorbs impact energy by allowing the bobbin to rotate in the webbing withdrawing direction by causing the bobbin to rotate. A hollow pie is integrally connected to the bobbin together with a shaft, and the other end of which is rotatable relative to the winding shaft. There the winding shaft is exterior to the seat belt apparatus provided with a retractor for a seat belt with an energy absorbing mechanism, characterized in that to absorb energy during relative rotation between the hollow pipe and the winding shaft.