JP2001225718A - Webbing winding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the optimum energy adsorbing effect in accordance with occupant's physique in a webbing winding device provided with a force limiter mechanism. SOLUTION: First and second torsion shafts 22 and 24 constituting a force limiter mechanism are inserted into a shaft core part of a spool shaft of the webbing winding device from both sides. A pair of lock means including acceleration sensors 34, 34' and having the same configuation are arranged in the webbing winding device by corresponding to it, and a lock shaft 40 making the acceleration sensors 34, 34' operating and non-operating conditions by a solenoid 48 is provided. Consequently, the first torsion shaft 22 only or the second torsion shaft 24 only or both them act as the force limiter mechanism in accordance with occupant's physique to obtain the optimum energy absorbing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a webbing winding device provided with a force limiter mechanism.

[0002]

2. Description of the Related Art A webbing take-up device, which is a main part of a seat belt device, is provided with a lock means for preventing the take-up shaft from rotating in the webbing pull-out direction when a sudden deceleration of a vehicle is detected. In recent years, improvements have been made to webbing take-up devices, which not only prevent the take-up shaft from rotating in the webbing pull-out direction when the vehicle suddenly decelerates, but also deform a specific member in consideration of the occupant to reduce the webbing. There is one that allows a predetermined amount of drawing and can absorb energy.

[0003] This type of mechanism is called a force limiter mechanism. In brief, when the load acting on the shoulder-side webbing or the lap-side webbing exceeds a certain value during rapid deceleration of the vehicle, a specific energy absorbing member is deformed. This allows the webbing to be withdrawn according to the amount of deformation of the energy absorbing member, and
Energy is absorbed by the deformation of the energy absorbing member. As a result, it is intended to reduce the load acting on the occupant's chest or waist through the webbing.

[0004]

However, the conventional force limiter mechanism only has a constant starting load. For this reason, the occupant wearing the seat belt device naturally has a physique difference, and the energy acting on the webbing at the time of sudden deceleration of the vehicle also has a corresponding difference, but only a uniform operation can be obtained. .

The present invention has been made in view of the above-described circumstances, and has as its object to provide a webbing retractor having a force limiter mechanism and capable of obtaining an optimum energy absorbing effect according to the occupant's physique.

[0006]

According to a first aspect of the present invention, there is provided a winding shaft for winding a webbing for restraining an occupant in a layered manner by an urging force, and the rotation of the winding shaft in the webbing withdrawing direction during a sudden deceleration of the vehicle. When the load applied to the webbing at the time of activation of the locking means and the locking means exceeds a certain value, the energy absorbing member is deformed to allow a predetermined amount of webbing to be withdrawn according to the amount of deformation. A force limiter mechanism that absorbs energy,
A webbing retractor configured to include an operation start load changing means for increasing or decreasing the operation start load for operating the force limiter mechanism based on the physique of the occupant wearing the webbing. I have.

According to the first aspect of the present invention, when the occupant pulls out the webbing from the winding shaft against the urging force and the webbing is mounted, when the vehicle suddenly decelerates, the locking means operates. As a result, rotation of the winding shaft in the webbing withdrawing direction is prevented. For this reason, the load applied to the webbing from the occupant who moves by inertia increases. When the applied load exceeds a certain value, the force limiter mechanism operates to deform the energy absorbing member. This allows a predetermined amount of webbing to be drawn out in accordance with the amount of deformation of the energy absorbing member, and energy is absorbed in accordance with the amount of deformation of the energy absorbing member.

[0008] By the way, the physique of the occupant wearing the webbing has individual differences. Some occupants have a large physique, and some occupants have a small physique. In the case of a large occupant, the load applied to the webbing increases, and accordingly, the operation start load of the force limiter mechanism is preferably set to be large. Conversely, in the case of a small occupant, the load acting on the webbing is reduced. Therefore, it is desirable that the operation start load of the force limiter mechanism is set small accordingly. In the present invention, in consideration of this point, an operation start load changing unit is newly provided, and the operation start load for operating the force limiter mechanism is increased or decreased based on the physique of the occupant.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A webbing winding device 10 according to an embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 and 2 are perspective views showing a main part of a webbing take-up device 10 according to this embodiment, and FIG. 3 is a schematic longitudinal sectional view of the webbing take-up device 10. The figure is shown.

As shown in FIG. 3, the webbing take-up device 10 includes a frame 12 formed in a U shape in plan view. The webbing take-up device 10 is fixed to a lower portion of a center pillar or the like by connecting an intermediate portion (not shown) of the frame 12 to a vehicle body with a bolt.

The frame 12 has a pair of leg plates 14 arranged in parallel with each other, and a spool 16 as a “winding shaft” is disposed between the leg plates 14. The spool 16 includes a spool shaft 16A on which one end of a webbing 18 for restraining an occupant is locked, and the spool shaft 16A.
Pair of disk-shaped flange portions 16B formed at both ends
And has a substantially drum shape as a whole. The spool 16 is urged in the webbing take-up rotation direction by receiving the urging force of a spring (not shown) provided on one leg plate 14 side.

As shown in FIG. 2 and FIG.
A hexagonal-shaped shaft is inserted into the shaft core of the spool 16.
A hole 20 is formed. Into this shaft insertion hole 20
Are the first torsion shaft 22 and the second torsion shaft.
The shafts 24 are inserted from opposite directions. First
One end 22A of the torsion shaft 22 is
It is formed in a hexagonal nut shape that can be inserted into the through hole 20.
You. Also, the other end 22B of the first torsion shaft 22
Is a disk formed on the shaft core of one flange 16B.
Disc-shaped base 22B fitted into the recess 26₁When,
The base 22B ₁Protruding from the center of the
Engagement portion 22B_TwoAnd is constituted by. Further
One end 22A of the first torsion shaft 22 and the other end
The intermediate portion 22C connecting the portion 22B is formed in a straight rod shape.
ing. Note that the second torsion shaft 24 also
Because of the same configuration, the first torsion shaft 2
Duplicate explanations are given by assigning the same signs as in 2.
I will love you.

[0014] The constricted portion of the base portion 22B ₁ of the first torsion shaft 22 described above, the first lock plate 28 of a pair of meniscus shape is loosely fitted. Lock teeth 28A are formed in a predetermined range of the outer peripheral portion of the first lock plate 28, and the lock teeth 28A are formed integrally with the one leg plate 14 of the frame 12 or are provided separately as internal teeth (not shown). It is arranged facing the ratchet teeth of the ratchet wheel.

Further, a first V gear 30 is disposed coaxially with the first torsion shaft 22 on the other end 22 B side of the first torsion shaft 22. The first
Boss 30A of V gear 30 and first torsion shaft 22
A biasing means such as a torsion coil spring attached by a resin component such as a cap with a claw (not shown) is interposed between the first torsion shaft 22 and the other end 22B. The first V gear 30 rotates following. Also, the boss 30 of the first V gear 30
Around the A, openings 33 for escape of the engagement portion 22B ₂ of the four first guide hole 32 and the first torsion shaft 22 is inserted is formed. A pair of projections 28B erected from the first lock plate 28 are inserted into the first guide holes 32, respectively.

A first acceleration sensor 34 is disposed below the lock teeth 30B of the first V gear 30.
The first acceleration sensor 34 has an L-shaped base 34 in side view.
A, a first ball 34B mounted on a concave surface formed at the center of the bottom of the pedestal 34A, one end is pivotally supported by the upper end of the vertical wall of the pedestal 34A and the other end is pivotally supported. And a first pawl 34C placed on the upper surface of the first ball 34B. A triangular first engagement claw 36 is integrally formed at the upper end on the other end side of the first pawl 34 </ b> C, and the first engagement claw 36 is a lock tooth 3 of the first V gear 30.
0B.

The above-described configuration is employed in the same manner on the second torsion shaft 24 side. Therefore,
The detailed description of the components on the second torsion shaft 24 side is omitted, but for convenience of description, in the following description, the components on the second torsion shaft 24 side will be the first.
The same number is assigned to the part on the torsion shaft 22 side, and “′” is added, and “first” in the part name is replaced with “second” to distinguish between the two.

Here, a stopper shaft 40 movably supported in the axial direction is disposed above the first pawl 34C of the first acceleration sensor 34 and the second pawl 34C 'of the second acceleration sensor 34'. ing. At a predetermined position in the longitudinal direction of the stopper shaft 40, a first stopper piece 42 and a second stopper piece 44, each formed in a rectangular shape, project in the same direction. The first stopper piece 42 is provided corresponding to the first engagement claw 36 of the first pawl 34C of the first acceleration sensor 34, and the second stopper piece 44 is provided for the second pawl 34C 'of the second acceleration sensor 34'. Of the second engaging claw 36 '. But,
The distance between the first stopper piece 42 and the second stopper piece 44 is
The distance is set larger than the distance between the first engagement claw 36 of the first acceleration sensor 34 and the second engagement claw 36 'of the second acceleration sensor 34'.

Further, one end of the stopper shaft 40 is connected to a solenoid 48 through a compression coil spring 46.
Is connected to The solenoid 48 is a controller 50
And its operation is controlled. The controller 50 includes a physique detection sensor 52 for detecting the physique of the occupant wearing the webbing 18.
Is connected to Various types can be applied to the physique detection sensor 52 and its use. For example, a seat-type pressure sensor is provided in a seat cushion of a vehicle seat, and the weight of the occupant is detected and the physique of the occupant is assumed and determined based on the weight. A type in which a drawer length of the webbing 18 is calculated by detection and a physique of an occupant is determined based on the calculated length, a type in which the position of a seat slide is detected and a physique of the occupant is determined based on the position, a roof head An infrared sensor, an ultrasonic sensor, or the like is provided at a predetermined position such as a lining so as to project or irradiate the occupant, and a type that directly detects the occupant's physique can be applied.

The first torsion shaft 2 described above
The deformation strength of the second intermediate portion 22C and the deformation strength of the intermediate portion 24C of the second torsion shaft 24 are set to different strengths. Incidentally, in the present embodiment, the FL load (which is a force limiter load, which corresponds to the “operation start load” in the present invention) of the first torsion shaft 22 is set to 150 [kgf], and the second torsion shaft The FL load of No. 24 is set to 350 [kgf].

Next, the operation and effect of this embodiment will be described.

When the occupant holds the tongue plate (not shown) inserted through the webbing 18 and pulls out the webbing 18 against the urging force of the mainspring, and engages the tongue plate with a buckle device (not shown), the occupant can enter the three-point system. The webbing of the seat belt device is set. That is, the webbing 18 from the shoulder anchor (not shown) to the tongue plate (not shown) disposed above the center pillar is the webbing on the shoulder side, and the webbing 18 from the tongue plate to the anchor plate is the webbing on the lap side.

When a normal drawing operation and a winding operation of the webbing 18 are performed, the hexagon nuts of the first torsion shaft 22 and the second torsion shaft 24 are inserted into the hexagonal hole-shaped shaft insertion holes 20 of the spool shaft 16A. Since the one ends 22A and 24A of the shape are inserted from both sides, the first torsion shaft 22 and the second torsion shaft 24 and further the first torsion shaft 24 as the spool 16 rotates.
The V gear 30 and the second V gear 30 'rotate together.

Here, when the occupant sits on the vehicle seat and wears the webbing 18, first, a physique detection sensor 52 detects a judgment material for judging the occupant's physique and outputs it to the controller 50. Controller 5
At 0, a predetermined calculation is performed based on the detection result of the physique detection sensor 52, and the physique of the occupant is determined. The occupant's physique is determined in three stages, for example, “standard physique”, “large physique”, and “small physique”.

For example, when the controller 50 determines that the size is "small physique", the first mode is set. That is, a predetermined current is supplied from the controller 50 to the solenoid 48 to be strongly excited. When the solenoid 48 is strongly excited, the compression coil spring 46 is contracted by a predetermined amount, and the stopper shaft 40 is held at the “first holding position”. When the stopper shaft 40 is held at the “first holding position”, the second stopper piece 44 is located above the second engagement claw 36 ′ of the second acceleration sensor 34 ′. However, the first stopper piece 42 is not located above the first engagement claw 36.

In the case where the first mode is set as described above, when the vehicle suddenly decelerates, both the first ball 34B and the second ball 34B 'are caused by the inertia force.
A, rolling on 34A ', pushing up the first pawl 34C and the second pawl 34C'. Since the first stopper piece 42 does not exist above the first engagement claw 36 of the first pawl 34C, the first engagement claw 36 becomes the lock tooth 30B of the first V gear 30.
Is engaged. Therefore, the rotation of the first V gear 30 in the webbing pull-out direction is prevented, and relative rotation occurs between the first V gear 30 and the spool shaft 16A. When relative rotation occurs between the two, the first lock plate 28 is guided by the first guide hole 32 to move in the radial direction, and the lock teeth 28A
Are engaged with the ratchet teeth of the internal ratchet wheel. As a result, the rotation of the first torsion shaft 22 and thus the spool shaft 16A in the webbing withdrawing direction is prevented, and the locked state is established.

However, at this time, the second pawl 34
A second stopper piece 44 is provided above the second engagement claw 36 'of C'.
Is present, the second engagement claw 36 'is connected to the second V gear 30'.
Does not engage with the lock teeth 30B 'of the first. Therefore, the second torsion shaft 24 is not locked, and is in a state where it can rotate integrally with the spool shaft 16A.

As described above, the first torsion shaft 2
When the rotation of the spool shaft 16A in the webbing pull-out direction is prevented by the rotation 2, the occupant attempts to inertia move toward the front side of the vehicle, so that the load acting on the webbing 18 increases. This acting load is a constant value (that is, 150 in the first mode).
[Kgf]: see FIG. 4), the force limiter mechanism starts operating. Specifically, plastic deformation occurs due to torsion in the intermediate portion 22C of the first torsion shaft 22, and the webbing 18 is allowed to be drawn out by a length corresponding to the plastic deformation amount, and the amount corresponding to the plastic deformation amount is determined. Only energy is absorbed.

On the other hand, when the controller 50 determines that the body size is "standard body size", the mode is set to the second mode.
That is, a predetermined current is supplied from the controller 50 to the solenoid 48 to weakly excite it. When the solenoid 48 is weakly excited, the compression coil spring 46 is contracted by a predetermined amount (a smaller amount than in the first mode), and the stopper shaft 40 is held at the “second holding position”. When the stopper shaft 40 is held at the “second holding position”, the first stopper piece 42 is located above the first engagement claw 36 of the first acceleration sensor 34. However, the second stopper piece 44 is not located above the second engagement claw 36 '.

When the vehicle is suddenly decelerated in the case where the second mode is set as described above, the first ball 34B and the second ball 34B 'are both driven by the inertia force.
A, rolling on 34A ', pushing up the first pawl 34C and the second pawl 34C'. Since the second stopper piece 44 does not exist above the second engagement claw 36 'of the second pawl 34C', the second engagement claw 36 'is engaged with the lock tooth 30B' of the second V gear 30 '. . Therefore, the rotation of the second V gear 30 ′ in the webbing withdrawal direction is prevented, and the second V gear 30 ′ is prevented.
And the spool shaft 16A generates a relative rotation. When a relative rotation occurs between the two, the second lock plate 28 'moves in the radial direction guided by the second guide hole 32', and the lock teeth 28A 'are engaged with the ratchet teeth of the internal ratchet wheel. You. As a result, the rotation of the second torsion shaft 24 and thus the spool shaft 16A in the webbing withdrawing direction is prevented, and the locked state is established.

However, at this time, the first pawl 34C
Since the first stopper piece 42 exists above the first engagement claw 36, the first engagement claw 36 does not engage with the lock teeth 30B of the first V gear 30. Therefore, the first torsion shaft 22 does not enter the locked state, and is in a state where it can rotate integrally with the spool shaft 16A.

As described above, the second torsion shaft 2
When the rotation of the spool shaft 16A in the webbing withdrawing direction is prevented by the step 4, the occupant tends to inertia move toward the front of the vehicle, so that the load acting on the webbing 18 increases. This applied load is a constant value (that is, 350 in the case of the second mode).
[Kgf]: see FIG. 4), the force limiter mechanism starts operating. Specifically, plastic deformation due to torsion occurs in the intermediate portion 24C of the second torsion shaft 24, so that the webbing 18 can be pulled out by a length corresponding to the plastic deformation amount, and an amount corresponding to the plastic deformation amount. Only energy is absorbed.

If the controller 50 determines that the size is "large", the third mode is set. That is, the solenoid 50 is controlled by the controller 50.
8 is de-energized and demagnetized. Solenoid 48
Is demagnetized, the stopper shaft 40 is extended by the urging force of the compression coil spring 46, and the stopper shaft 40 is held at the “third holding position”. When the stopper shaft 40 is held at the “third holding position”, the first stopper piece 42 is not located above the first engagement claw 36 of the first acceleration sensor 34, and the second stopper piece 44 Second engagement piece 36 'of second acceleration sensor 34'
Is not located above.

In the case where the third mode is set as described above, when the vehicle suddenly decelerates, both the first ball 34B and the second ball 34B 'are caused by the inertia force of the pedestal 34.
A, rolling on 34A ', pushing up the first pawl 34C and the second pawl 34C'. Since neither the first stopper piece 42 nor the second stopper piece 44 exists above the first engagement claw 36 and the second engagement claw 36 ', the operation in the first mode and the operation in the second mode described above are not performed. Both are performed. For this reason, both the first torsion shaft 22 and the second torsion shaft 24 are prevented from rotating in the webbing withdrawing direction, and the spool shaft 16A is rotated by both.
Is prevented from rotating in the webbing pull-out direction, and the webbing is locked.

As described above, the first torsion shaft 2
When the rotation of the spool shaft 16A in the webbing pull-out direction is blocked by the second and second torsion shafts 24, the occupant tends to inertia move toward the front of the vehicle, so that the load acting on the webbing 18 increases. When the applied load exceeds a certain value (that is, 500 kgf in the third mode: see FIG. 4), the force limiter mechanism starts operating. Specifically, the intermediate portion 22C of the first torsion shaft 22 and the intermediate portion 24C of the second torsion shaft 24
The plastic deformation due to the torsion occurs, and the webbing 18 is allowed to be drawn out by a length corresponding to the plastic deformation amount, and the energy is absorbed by an amount corresponding to the plastic deformation amount.

As described above, according to the present embodiment, the operation start load for operating the force limiter mechanism is increased or decreased based on the physique of the occupant wearing the webbing 18, so that the optimum energy is adjusted according to the physique of the occupant. An absorption effect can be obtained.

In this embodiment, since the FL load of the first torsion shaft 22 and the FL load of the second torsion shaft 24 are set to different values, it is possible to make a combination from the first mode to the third mode. it can.

Further, in the present embodiment, since the configuration of the locking means and the configuration of the force limiter mechanism are symmetrical, the number of components does not increase even if the number of components increases. For this reason, it can contribute to cost reduction.

In the present embodiment, the FL load of the first torsion shaft 22 and the FL load of the second torsion shaft 24 are set to different values. However, the present invention is not limited to this, and may be set to the same value. . In this case, there are two types of modes.

In this embodiment, the number of parts can be reduced.
From the viewpoint of simplification of the structure and the like, one stopper shaft 40 is moved in the axial direction by a single solenoid 48 to switch the mode. However, the first acceleration sensor 34 and the second acceleration sensor 34 ' On the other hand, the operation start load changing means may be set separately and independently. In this case, a mode in which the FL load is 0 [kgf] (that is, a mode in which the force limiter mechanism is not operated) can be created, and the types of modes can be increased.

Furthermore, in the present embodiment, the first torsion shaft 22 and the second torsion shaft 24 are inserted into the shaft insertion hole 20 to constitute the force limiter mechanism. However, the present invention is not limited to this, and various configurations may be adopted. Is possible.

The correspondence between the components of the present embodiment and the components of the present invention will be supplemented by describing the first lock plate 28, the first V gear 30, the first acceleration sensor 34, the second lock plate 28 ', and the second V gear. 30 'and the second acceleration sensor 34' correspond to "lock means". The first torsion shaft 22 and the second torsion shaft 24 correspond to the “energy absorbing member” of the present invention, and the combination of these elements and the shaft insertion hole 20 corresponds to the “force limiter mechanism” of the present invention. .
Further, the stopper shaft 40 (the first stopper piece 42,
The second stopper piece 44), the compression coil spring 4
6, the solenoid 48, the controller 50, and the physique detection sensor 52 correspond to "operation start load changing means" in the present invention. In a broad sense, the controller 50 is an element grasped as “control means”, and the physique detection sensor 52 is an element grasped as “physique detection means”.

[0043]

As described above, the webbing take-up device according to the first aspect of the present invention operates to increase or decrease the operation start load for operating the force limiter mechanism based on the physique of the occupant wearing the webbing. Since the load changing means is provided, there is an excellent effect that an optimum energy absorbing effect can be obtained according to the occupant's physique.

[Brief description of the drawings]

FIG. 1 is a perspective view showing main parts (a first acceleration sensor, a second acceleration sensor, a stopper shaft, and the like) in a webbing take-up device according to an embodiment.

FIG. 2 is an exploded perspective view of the webbing retractor according to the embodiment.

FIG. 3 is a schematic longitudinal sectional view in a state where the webbing take-up device shown in FIG. 2 is assembled.

FIG. 4 is a table for explaining the operation of the webbing take-up device according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Webbing take-up device 16 Spool (winding shaft) 18 Webbing 20 Shaft insertion hole (force limiter mechanism) 22 1st torsion shaft (energy absorption member, force limiter mechanism) 24 2nd torsion shaft (energy absorption member, force limiter mechanism) ) 28 1st lock plate (locking means) 30 1st V gear (locking means) 34 1st acceleration sensor (locking means) 28 '2nd lock plate (locking means) 30' 2nd V gear (locking means) 34 '2nd Acceleration sensor (locking means) 40 Stopper shaft (operation start load changing means) 46 Compression coil spring (operation start load changing means) 48 Solenoid (operation start load changing means) 50 Controller (operation start load changing means) 52 Physical size detection sensor ( Operation start load change Stage)

Claims (1)

[Claims] 1. A winding shaft for winding a webbing for restraining an occupant in a layered manner by an urging force, a locking means for locking rotation of the winding shaft in a webbing pull-out direction when the vehicle is suddenly decelerated, and a webbing when the locking means is operated. A force limiter mechanism that deforms the energy absorbing member when the applied load exceeds a certain value, thereby allowing a predetermined amount of webbing to be drawn out according to the amount of deformation and absorbing energy. Webbing take-up device provided with an operation start load changing means for increasing / decreasing an operation start load for operating a force limiter mechanism based on a physique of an occupant wearing the webbing. apparatus.