JPH11139248A - Webbing winding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a webbing winding device which can reduce tensile load applied to webbing during operation of a force limiter, without reducing a tensile force applied to the webbing during operation of a pretensioner. SOLUTION: A pretensioning shaft part 26 at one end of a spool 18 is arranged with a space from a drum 64. During sudden deceleration, the drum 64 bites the pretensioning shaft part 26. Because the pressing part 112 of a drive plate 80 presses a position near the root of an engaging piece 76, a rupturing part 72 is not ruptured, and the drum 62 rotates the spool 18 in the direction for winding webbing 20. If a drawing force not smaller than a predetermined value works on the webbing 20, the end portion of the engaging piece 76 is pressed by the end of a pressing piece 114, and a large bending moment works, causing rupturing of the engaging piece 76 at the rupturing part 72, followed by the operation of a force limiter to twist and deform a torsion bar 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a webbing take-up device provided with a pretensioner for tensioning a webbing at the time of rapid deceleration of a vehicle and a force limiter for preventing a webbing from being subjected to a pulling force exceeding a predetermined value.

[0002]

2. Description of the Related Art A webbing take-up device mounted on a vehicle is provided with a pretensioner that takes up and tensions the webbing when a large deceleration greater than a predetermined value is applied to the vehicle, and restrains the wearer without loosening. (See JP-A-4-92748). FIG. 15 shows a webbing take-up device 30 having such a pretensioner.
0 is shown.

On the other hand, there has been proposed a webbing winding device provided with a force limiter for preventing a tensile force applied to the webbing from exceeding a predetermined value.

In the webbing take-up device 300 shown in FIG. 15, the drum 310 is wound around the wire 318 at the time of rapid deceleration of the vehicle, the holding portion 312 holds the pretensioning shaft portion 308, and the drum 310 moves together with the spool 306. Because it is designed to rotate, wire 3
18 is pulled out to the maximum, the spool 306 is further webbed 304 due to the tension of the wire 318.
It cannot be rotated in the pull-out direction. Therefore, if the above-mentioned force limiter is simply attached to the webbing take-up device 300, the tension of the webbing 304 by the pretensioner is released, and the torsion bar cannot be sufficiently twisted.

In order to solve such a problem, for example, with the wire 318 being pulled out to the maximum, the cylinder 32
4 (for example, a wire 318) from a piston (not shown) to the pretensioning shaft portion 308.
And the drum 310), a rupture portion is formed which is broken by a tensile force exceeding a predetermined value applied to the webbing 304, and the spool 306 is rotated in the pull-out direction of the webbing 304 independently of the pretensioner due to the rupture of the rupture portion. It is possible to make it possible. However, it is necessary that the broken portion is not broken when the pretensioner is operated, but is broken when the force limiter is operated.Therefore, without reducing the pulling force against the webbing during the operation of the pretensioner, the broken portion can be used when the force limiter is operated. However, it is not possible to reduce only the pulling load applied to the webbing (release load required to release the webbing 304 from being pulled by the pretensioner).

[0006]

SUMMARY OF THE INVENTION In consideration of the above fact, the present invention can reduce the tensile load applied to the webbing when the force limiter is operated without reducing the tensile force on the webbing when the pretensioner is operated. It is an object to obtain a winding device.

[0007]

According to the first aspect of the present invention, the spool on which the webbing is wound is deformed by the spool when a rotational force in the webbing pull-out direction acts on the spool during rapid deceleration of the vehicle. An energy absorbing member for preventing an increase in webbing tension, a rotating member that rotates in the webbing winding direction when a deceleration of a predetermined value or more acts, and a rotatable member integrally rotatable with the rotating member; Then, a connecting member connected to the spool and the connecting member protruded from the connecting member, and when the rotating member rotates in the webbing winding direction, the rotating member is pressed in the vicinity of the root, and the connecting member is pulled out of the spool by the webbing. An engagement piece that is pressed against a portion closer to the distal end than near the root when rotated by receiving a rotational force in the direction. When the energy absorbing member is deformed by the rotational force in the webbing withdrawing direction and the rotating member presses a portion of the engaging piece closer to the tip than near the base, the rotational force in the webbing withdrawing direction is reduced. And a release portion for releasing the rotation of the pretensioner in the webbing withdrawal direction.

[0008] In a normal running state of the vehicle in which the deceleration equal to or more than the predetermined value is not applied, the pretensioner does not restrain the spool.

When a deceleration equal to or more than a predetermined value acts, the rotating member rotates in the webbing winding direction. Further, the connecting member is connected to the spool. As a result, the rotation of the rotating member is transmitted from the engagement piece to the spool via the connecting member, and the webbing is wound around the spool, so that the webbing restrains the wearer without loosening.

Next, when the webbing is pulled in the pull-out direction, the pulling force is transmitted from the spool to the energy absorbing member. Due to the energy absorbing action such as the deformation of the energy absorbing member, the action of the force limiter for preventing the mounting force on the webbing wearer from exceeding a predetermined value is started. When the webbing is further pulled against this, and the connecting member rotates by receiving the rotational force in the webbing pull-out direction of the spool, a portion closer to the tip end than near the base of the engagement piece is pressed by the rotating member. . At this time,
A larger bending moment acts on the engagement piece than when the rotation member rotates in the webbing winding direction (the vicinity of the root of the engagement piece is pressed by the rotation member). The release unit receives the rotational force in the webbing pull-out direction and releases the rotation stop in the webbing pull-out direction by the pretensioner, so that the spool can rotate relative to the pretensioner. Therefore, in this state, the energy absorption further continues, the operation of the force limiter is continued, and the mounting force of the webbing to the wearer does not exceed a predetermined value.

As described above, when the energy absorbing member is deformed by the rotational force in the webbing pulling-out direction, a portion of the engaging piece closer to the distal end than the vicinity of the base is pressed, and a large bending moment acts on the engaging piece. The release section releases the rotation prevention in the webbing pull-out direction by the pretensioner, but when the pretensioner is activated, the vicinity of the base of the engagement piece is pressed,
Since the release unit does not release the rotation inhibition in the webbing withdrawal direction, it is possible to reduce only the tensile load during the operation of the force limiter without reducing the tensile force during the operation of the pretensioner.

The release section may be any release section which can rotate the spool relative to the pretensioner. For example, the release section may be a plastic deformation member, an elastic deformation member, a breaking member, a clutch, a friction plate, or the like. Etc.

According to a second aspect of the present invention, in the first aspect of the present invention, the release portion is formed at a root portion of the engagement piece, and the rotation member presses the vicinity of the root of the engagement piece. It is characterized in that it is a fractured portion that is not broken when it is broken, and has a strength that is broken when it is pressed on a portion on the tip side of the vicinity of the root.

When the rotating member rotates in the webbing winding direction when a deceleration equal to or more than a predetermined value acts, the rotating member presses the vicinity of the base of the engaging piece protruded from the connecting member. The bending moment acting on the formed break is reduced, and substantially only shear forces act. Since the breaking portion has such a strength that it is not broken only by the shearing force caused by the pressing, the breaking piece is not broken, and the engaging piece is pressed by the rotating member to rotate the connecting member. The connecting member is connected to the spool, and the rotation of the rotating member in the webbing winding direction is transmitted to the spool via the connecting member. Therefore, the spool rotates in the webbing winding direction, and the webbing is wound.

When the energy absorbing member is deformed by the rotational force in the webbing withdrawing direction and the connecting member is rotated in the webbing withdrawing direction by receiving the rotational force in the webbing withdrawing direction, the rotating member is moved closer than the vicinity of the base of the engagement piece. Press the tip side part. For this reason, a larger bending moment acts on the fractured portion than when the vicinity of the root is pressed (the shearing force also acts). The breaking portion is broken because it has a strength to be broken by a bending moment due to this pressing. As a result, the spool is separated from the pretensioner, so that the spool can freely rotate with respect to the pretensioner.

As described above, when the rotating member rotates in the webbing winding direction, the breakage of the breaking portion is avoided, and when the connecting member rotates by receiving the rotational force of the spool in the webbing pulling-out direction, the breaking portion is prevented from breaking. By breaking, only the tensile load during the operation of the force limiter can be reduced without reducing the tensile force during the operation of the pretensioner.

[0017]

1 to 3 show a webbing winding device 10 according to an embodiment of the present invention.

The webbing take-up device 10 has a frame 12 mounted on a vehicle (not shown). A pair of support plates 14 and 16 are arranged on the frame 12 in parallel. Between the support plates 14 and 16, there is provided a spool 18 which is formed into a substantially cylindrical shape and has flanges projecting from both ends in the axial direction in the radial direction. This spool 1
8, one end of the webbing 20 is fixed, and the webbing 20 is wound up. FIGS. 1 and 2 show a state in which the webbing 20 is wound up on the spool 18. I have. FIG. 3 shows a state in which the webbing 20 is pulled out from the spool 18.

Inside the spool 18, a torsion portion 22 is disposed coaxially with the center axis of the spool 18. The torsion portion 22 has a substantially columnar torsion bar 24 that is slightly longer than the axial length of the spool 18. The torsion bar 24 is made of a plastically deformable material such as a metal, and is plastically deformed and twisted when a torsional force of a predetermined value or more acts in the circumferential direction.

At one end of the torsion bar 24, a hexagonal columnar insertion portion 24A is formed. The insertion portion 24A
A hexagonal insertion hole 34 (see FIGS. 2 and 3) formed in the pretensioning shaft portion 26 constituting the torsion portion 22.
), And the torsion bar 24 and the pretensioning shaft 26 rotate integrally.

The pretension shaft portion 26
A holding portion 28 having a substantially cylindrical shape, and a cylindrical gear portion 30 having a smaller diameter than the holding portion 28 and integrally formed coaxially with the holding portion 28 (see FIGS. 2 and 3). doing. A plurality of projections 32 (see FIG. 1) having the same direction as the central axis direction of the torsion bar 24 and having a sharply pointed tip project on the outer periphery of the held portion 28 at predetermined intervals in the circumferential direction. Has been established. The projections 32 bite into the inner surface of the drum 64 when the holding portions 66, 68 of the drum 64, which will be described later, hold the holding portion 28, thereby preventing the drum 64 from running idle.

An external gear 36 is formed on the outer periphery of the gear portion 30. The external gear 36 meshes with the internal gear 38 formed on the inner periphery of the spool 18 over the entire circumference.
The spool 18 and the pretension shaft 26 rotate integrally. Accordingly, the torsion bar 24 rotates integrally with the spool 18 via the pretensioning shaft portion 26 at one end thereof.

On the other end side of the torsion bar 24 (the upper left side in FIG. 1, and the right side in FIGS. 2 and 3), a locking shaft section 40 constituting the torsion section 22 is arranged. The lock shaft portion 40 is formed in a substantially cylindrical shape, a hexagonal insertion hole 44 is formed in the axial direction from one end side, and a cylindrical portion 42 having an external thread 46 cut on the outer periphery. It is formed on the other end side, closes the insertion hole 44 and
, And a locked piece 50 protruding bifurcated from the circular plate 48.
A hexagonal columnar insertion portion 24B formed at the other end of the torsion bar 24 is inserted into the insertion hole 44, and the torsion bar 24 and the lock shaft portion 40 rotate integrally. FIG. 1 shows a state in which the insertion portion 24B is inserted into the insertion hole 44.

With the insertion portion 24B of the torsion bar 24 inserted into the insertion hole 44 in this manner, the spool 18 is disposed between the support plates 14 and 16, and the pretension shaft portion is positioned from the support plate 14 side. 26 is engaged with the internal gear 38 of the spool 18, and the torsion bar 24 integrated with the locking shaft portion 40 is inserted into the spool 18 from the support plate 16 side. As shown in FIG. 3, a torsion bar 24 is disposed in the spool 18 coaxially with the spool 18.
At this time, the cylindrical portion 42 side of the outer peripheral surface of the disc 48 from the substantially central portion in the axial direction abuts on the inner peripheral surface of the spool 18, and the torsion is maintained in a state where the central axis of the spool 18 and the central axis of the torsion bar 24 coincide. The part 22 is positioned. In addition, the locked piece 50 is located at a substantially axial center of the outer peripheral surface of the disc 48.
The side is rotatably supported by a support plate 16 of the frame 12 via a ring 52. A portion of the gear portion 30 of the pretensioning shaft portion 26 where the external gear 36 is not formed is rotatably supported by a cover drum 58 described later. Thereby, the spool 18 is rotatably supported by the frame 12.

The male screw 46 of the cylindrical portion 42 is formed into a substantially annular shape, a part of which is cut in the circumferential direction, and is threadedly engaged with a ring-shaped ring 54 having a female screw cut inside. With the torsion portion 22 disposed inside the spool 18,
The circumferential end face 54A of the ring-break ring 54 is
Abuts on a ridge 56 (see FIGS. 2 and 3) protruding from the inner periphery of the spool 18 along the axial direction of the spool 18. In a normal state, the ring-opening ring 54 is located at one end of the male screw 46 (the pretensioning shaft 26 side, the position shown in FIG. 2), but when the spool 18 rotates relatively to the locking shaft 40. The ring ring 54 also rotates with the spool 18 and moves to the other end (the disk 48 side, the position shown in FIG. 3). This movement is stopped when the ring-opening ring 54 comes into contact with the disk 48, and the rotation of the spool 18 with respect to the locking shaft 40 is also stopped.

An inertia lock mechanism (not shown) is provided outside the support plate 16 (on the side opposite to the side on which the spool 18 is provided, on the right side in FIGS. 2 and 3). This inertial lock mechanism is used to rotate the torsion portion 22 in the direction in which the webbing 20 is pulled out when a deceleration of a predetermined value or more acts on the vehicle to which the webbing take-up device 10 is attached or when the webbing 20 is pulled out rapidly. Is locked, but the locked piece 50 is not locked in the webbing 20 winding direction.

On the other hand, on the outside of the support plate 14 (the left side in FIGS. 2 and 3), a cover drum having accommodation portions 60 and 62 whose diameter is increased stepwise from the rotation axis of the torsion bar 24 toward the outside in the radial direction. 58 is fixed. A drum 64 around which a wire 94 to be described later is wound is accommodated in the accommodation portion 60 having a smaller diameter (the side closer to the support plate 14).
4 and are arranged coaxially.

The drum 64 is formed of a metal (such as aluminum) that is softer than the lock shaft portion 40 and the pretension shaft portion 26. Further, as shown in detail in FIG. 4, the drum 64 is arranged such that the substantially semi-annular holding portions 66 and 68 face each other to form a substantially cylindrical shape. In this state, the holding portions 66 and 68 Corresponding portions at both ends in the circumferential direction are connected by a substantially S-shaped compression section 70 integrally formed with the holding sections 66 and 68. Normally, as shown in FIG. 5A, the inner surfaces of the holding portions 66 and 68 and the projections 32 of the held portion 28 are kept in a state where the drum 64 is disposed in the accommodation portion 60 (see FIGS. 2 and 3). The drum 64 is separated from the pretension shaft portion 26 in the housing portion 60, but a force in the direction approaching the holding portions 66, 68 acts on the holding portion 66, 68. When the compression section 70 (see FIG. 4) is compressed and deformed and the holding sections 66 and 68 approach each other as shown in FIG. 7A, the holding sections 66 and 68 hold the section 28 to be held.
Since the drum 64 is formed of a metal softer than the pretensioning shaft portion 26, the projections 32 bite into the inner surfaces of the holding portions 66 and 68. For this reason, the drum 64 and the pretension shaft 26 rotate integrally.

A substantially flat engagement piece 76 is provided on an end face 66A at one axial end of the holding portion 66 so as to extend radially outward from substantially the center in the circumferential direction. On the tip side of the engagement piece 76,
A thick portion 76B wider and thicker than the engagement piece 76 is formed and reinforced. The root of the engagement piece 76 is a break 72. The tip of the engagement piece 76 (the thick portion 76
When a force equal to or more than a predetermined value in the circumferential direction of the drum 64 is applied to or near B), the breaking portion 72 is broken by receiving a bending moment. The engagement piece 76 is separated from the drum 64 by the breakage of the breakage portion 72. On the other hand, even if a force greater than or equal to a predetermined value in the circumferential direction of the drum 64 is applied at a position near the root of the broken portion 72,
Is smaller than when a force is applied to the tip of the engagement piece 76 (the thick portion 76B) or its vicinity. The breaking portion 72 has a predetermined strength so that the breaking portion 72 is not broken by this bending moment.

A positioning projection 73 is formed at the tip of the engaging portion 76. Further, a positioning projection 74 is formed on an end surface 66 on one end side in the axial direction of the holding portion 68. As shown in FIG. 5A, the webbing take-up device 10
In the assembled state, the positioning projections 73 and 74 are housed in housing recesses 106 and 108 of the drive plate 80 described later. As a result, the drum 64 is positioned in the radial direction with respect to the cover drum 58.

A flange 78 protruding outward is formed on the other end of the holding portions 66 and 68 in the axial direction.
68 are reinforced.

A substantially disk-shaped drive plate 80 is disposed outside the cover drum 58 (opposite to the support plate 14, left side in FIGS. 2 and 3). Surrounding three places, it is rotatable coaxially with the torsion bar 24. FIG.
As shown in (A), an insertion hole 82 into which the drum 64 is inserted is formed in the center of the drive plate 80, and when the drum 64 is inserted, the end surface 66 of the holding portion 66 is formed.
A and the end face 68A of the holding portion 68
, The drum 64 is positioned in the axial direction.

The insertion hole 82 is formed with a substantially fan-shaped accommodating portion 110 which gradually widens toward the outside in the radial direction. The engagement piece 76 is accommodated in the accommodation portion 110. When the cover drum 58 rotates relative to the drum 64 in the webbing take-up direction, the housing portion 110 has a pressing portion 112 that presses the vicinity of the root of the engagement piece 76 (near the break portion 72). Are formed.

Further, a housing recess 106 for housing the positioning projection 73 is formed at the tip of the housing portion 110. The accommodation recess 10 for accommodating the positioning protrusion 74 is provided at a position axially symmetric with respect to the accommodation portion 110 with respect to the insertion hole 82.
8 are formed.

The drive plate 80 has a fixing portion 84 to which a cylindrical body attached to one end of the wire 94 is fitted and fixed. The wire 94 having one end fixed to the fixing portion 84 is wound around the drum 64 a plurality of times (almost twice in this embodiment), and the other end is connected to a piston 88 in a cylinder 86 provided on the frame 12. (FIG. 5
(A) and is fixed to the outside of the cylinder 86. When a sensor (not shown) detects that a deceleration of a predetermined value or more has acted on the vehicle to which the webbing take-up device 10 is attached, a gas generator (not shown) in the base cartridge 90 provided on the frame 12 operates. 6 (B), FIG. 7 (B), FIG. 8 (B)
And, as shown in FIG. 9B, the piston 88 is rapidly moved toward the inside of the cylinder 86. This piston 88
The wire 94 is rapidly pulled in by the movement of the drive plate 80, and a rotational force is applied to the drive plate 80.

As shown in FIGS. 1 and 5A, a shear pin 92 projects from the frame 12 through the cover drum 58, and the shear pin 92 is formed in a recess formed in the drive plate 80. Normally, the drive plate 80 does not rotate in the webbing 20 winding direction (the direction of the arrow A in FIG. 5A) because the wire 94 is engaged with the webbing 20. When a rotation force equal to or greater than a predetermined value acts on the drive pin 80, the shear pin 92 is pushed by the recess 101 and is broken, so that the drive plate 80 rotates.

Outside the drive plate 80, a substantially annular stopper plate 96 is arranged. The stopper plate 96 is supported by a positioning member (not shown) coaxially with the torsion bar and rotatably about a central axis J (see FIG. 1) of the torsion bar 24. (Note that, in FIGS. 2 and 3, the stopper plate 96 and a cover plate
Is omitted. The movable projection 9 extends radially outward from the stopper plate 96 and has a tip portion bent at a substantially right angle toward the drive plate 80 side.
8 are formed. The tip of the moving projection 98 is located in a long groove 100 cut out in a substantially arc shape along the circumferential direction of the drive plate 80, and the relative rotation of the stopper plate 96 and the drive plate 80 causes the moving protrusion 98 to be elongated. Move within 100. The central angle of the long groove 100 is set to about 150 °, and the stopper plate 96 and the drive plate 80 rotate relatively by about 150 °.

The stopper plate 96 has a movable projection 98.
Webbing winding direction rear side (direction of arrow A in FIG. 5)
A pressing piece 114 protruding toward is formed. The pressing piece 114 is substantially wedge-shaped, and the position of the tip is in an assembled state.
The engaging piece 76 is formed so as to be in a position where it can contact the tip of the engaging piece 76 from the side. As shown in FIG. 7 (A), the drum 64 further moves in the webbing pull-out direction in a state where the moving protrusion 98 hits a stopper protrusion 104 to be described later, and the rotation of the stopper plate 96 in the webbing pull-out direction (arrow B direction) is stopped. When trying to rotate, the engagement piece 7
6 is pressed against the tip of the pressing piece 114. As a result, a large bending moment acts on the broken portion 72 of the engaging piece 76 in addition to the shearing force, and the engaging piece 76
Is to be broken.

Further outside the stopper plate 96,
The cover plate 102 is disposed and the cover drum 58
It is fixed to. The cover plate 102 maintains the state in which the drum 64, the drive plate 80, and the stopper plate 96 are housed in the housing portions 60 and 62 of the cover drum 58.

A stopper projection 104 projects from the cover plate 102 toward the stopper plate 96. The stopper projection 104 has a length that abuts the moving projection 98 but does not enter the long groove 100. As shown in FIG. 5A, the webbing take-up device 10
When the deceleration of a predetermined value or more is not acting on the stopper projection 104, the moving projection 98 of the stopper plate 96 is located on the lower right side of the paper of the stopper projection 104 (on the webbing 20 winding direction side),
Further, an end wall 100A of the long groove 100 of the drive plate 80 is located on the lower right side of the drawing.

When the wire 94 is pulled into the cylinder 86 and the drive plate 80 rotates in the webbing winding direction (the direction of arrow A in FIG. 5A), the pressing portion 11
2A presses the vicinity of the base of the engagement piece 76, so that FIG.
The drum 64 also rotates as shown in FIG. When the drive plate 80 further rotates, as shown in FIG.
The rotation of the drum 64 is performed by pressing the pressing piece 114 with the stopper projection 10.
4, but the moving projection 98 is
The stopper plate 96
Rotates. Then, the wire 94 is drawn into the cylinder 86 by the piston 88, and the piston 88 bottoms in the cylinder 86, and the drawing of the wire 94 is completed.
The rotation of the drive plate 80 stops.

As described above, the drive plate 80 rotates about 360 ° together with the stopper plate 96 in the initial rotation,
Next, since only the drive plate 80 rotates about 150 °, it rotates about 510 ° from the start to the end of rotation. The rotation amount of the drive plate 80 can be changed by changing the length of the long groove 100, thereby changing the rotation amount of the relative rotation between the drive plate 80 and the stopper plate 96. During the rotation of the drive plate 80, the moving projection 98 may be located at any position in the long groove 100, and the drive plate 80 may be rotated by about 510 ° from the start of rotation to the end of rotation.

Next, the operation and operation of the webbing take-up device 10 according to the present embodiment will be described.

In a normal state, that is, when the deceleration of the vehicle to which the webbing take-up device 10 is attached is less than a predetermined value, the inertia lock mechanism (not shown) uses the locked piece 5.
0 is not locked. Since the gas generator in the base cartridge 90 is not operating, the wire 94 is not drawn into the cylinder 86. Therefore, the spool 18 (see FIGS. 1 to 3) freely rotates, and the webbing 20 can be pulled out and taken up.

When a deceleration exceeding a predetermined value acts on the vehicle,
The inertia lock mechanism pulls out the webbing 20 (FIG. 5A).
In order to lock the rotation of the locked piece 50 in the direction of arrow B), the spool 18 that rotates together with the torsion portion 22 also
The rotation of the webbing 20 in the pulling-out direction is locked, and the webbing 20 cannot be further pulled out.

Further, the gas generator operates, and FIG.
As shown in (B), in order to move the piston 88 toward the inner side of the cylinder 86, the wire 94
It is quickly drawn into 6. Here, the drive plate 80 does not rotate because the rotation is stopped by the shear pin 92. In addition, since the positioning projections 73 and 74 are housed in the housing recesses 106 and 108, the drum 64 does not rotate. For this reason, the drum 64 around which the wire 94 is wound is sharply wound by the wire, and the compressing portion 70 (see FIG. 4) is compressed and deformed, and as shown in FIG. Approach each other and clamp the clamped portion 28 of the pretensioning shaft portion 26. At this time, the wire 94 is connected to the drum 64 in FIG.
6A, the shaft center of the drum 64 is shifted from the shaft center of the pinched portion 28, and moves substantially downward in FIG. The portion bites into the pinched portion 28. By this movement, the positioning projections 73 and 74 also move with respect to the accommodation recesses 106 and 108 in FIG.
(A) Since the positioning projections 73 and 74 move downward, the positioning projections 73 and 74 are broken. As shown in FIG.
When the drum 4 is pulled into the cylinder 86, as shown in FIG. 7A, the lower portion of the drum 64 also bites the pinched portion 74, and the drum 64 bites the pinched portion 74 over the entire circumference. The drum 64 and the pretension shaft 26 are integrated. At this time, the axis of the drum 64 coincides with the axis of the held portion 74 again.

When the wire 94 is further drawn into the cylinder 86, a rotational force acts on the drive plate 80,
The recess 101 presses the shear pin 92 to break it. As a result, as shown in FIG. 8A, the drive plate 80 rotates in the webbing winding direction (the direction of arrow A). The engaging piece 76 of the drum 64 is accommodated in the accommodating portion 110 of the drive plate 80, and the pressing portion 112 presses the position near the base of the engaging piece 76, so that the bending moment acting on the breaking portion 72 is very small. Thus, substantially only the shearing force acts on the broken portion 72. Since the strength of the breaking portion 72 is set so as not to be broken by the shearing force, the breaking portion 72 is not broken and the drum 64 is not broken.
Rotates together with the drive plate 80 in the webbing pull-out direction.

An external gear 36 formed on the gear portion 30 of the pretensioning shaft portion 26 is engaged with an internal gear 38 on the inner periphery of the spool 18, and an inertia lock mechanism (not shown) Webbing 20 of shaft portion 40
Since the rotation in the winding direction (the direction of the arrow A) is not locked, the rotation of the drum 64 causes the spool 18 to rotate in the winding direction of the webbing 20 (the direction of the arrow A) via the shaft portion 26 for pretension. As shown in FIG. 9 (B), when the piston 88 moves deep inside the cylinder 86 and the wire 94 is pulled most into the cylinder 86,
As shown in FIG. 9A, the drive plate 80 is rotated by about 510 ° from the initial state, and the webbing 20 is tense most. Thereby, the webbing 20 is attached to the wearer of the webbing 20 without slack.

Next, when a withdrawal force exceeding a predetermined value acts on the webbing 20 due to the inertia force of the wearer of the webbing 20, this force acts on the spool 18 in the webbing 20 withdrawing direction (the direction of arrow B in FIG. 10A). Acts as a turning force. Here, the inertia locking mechanism (not shown) locks the rotation of the locking shaft 40 in the direction in which the webbing 20 is pulled out.
Bar 2 into which the insertion portion 24B at the other end is inserted.
4 is also locked at the other end. On the other hand, the insertion portion 24A at one end of the torsion bar 24 is inserted into the pretensioning shaft portion 26, and the pretensioning shaft portion 26 is engaged with the external gear 36 and the internal gear 38 so that the spool 18 And rotate together. The rotational force of the spool 18 is transmitted to the torsion bar 24 via the pretension shaft portion 26, and the torsion bar 24
Begins to be plastically deformed and twisted, and begins to act as a force limiter for preventing a tensile force exceeding a predetermined value from acting on the webbing 20.

At this time, when the spool 18 rotates with respect to the locking shaft portion 40, the end surface 5
4A is pushed by the ridge 56, and the ring-break ring 54 rotates, and starts to move toward the disk 48.

The drum 64 that has been cut by the pinched portion 28 of the pretension shaft portion 26 is also
Since the drive plate 80 rotates in the pull-out direction (the direction of the arrow B in FIG. 9A), the drive plate 80 also rotates in the pull-out direction of the webbing 20, and the wire 94 is pulled in the cylinder 86.
As shown in FIG. 0 (B), the piston 88 moves inside the cylinder 86 to the left in the drawing.

At this time, as shown in FIG. 10A, the drum 64 presses the pressing portion 112 of the drive plate 80 at a position near the base of the engagement piece 76, so that the drum 64 and the drive plate 80 are integrated. And webbing 2
0 Rotate in the pull-out direction (arrow B direction). In addition, the long groove 10
Since the moving projection 98 is housed in the drive plate 80, the drive plate 80 also rotates relative to the stopper plate 96 in the webbing 20 pulling-out direction (the direction of arrow B).

As shown in FIG. 11A, the drive plate 80 is rotated to the substantially same state as the initial state (the state shown in FIG. 5A), and the moving projection 98 is moved to the stopper projection 104.
, The rotation of the stopper plate 96 is stopped. In this state, when a rotational force is further applied to the spool 18 in the webbing 20 pulling-out direction (the direction of arrow B), the drum 6
4 tries to rotate in the webbing 20 pull-out direction,
The tip of the engaging piece 76 is pressed against the tip of the pressing piece 114. As a result, a large bending moment acts on the broken portion 72 of the engagement piece 76 in addition to the shearing force.
As shown in (A), the engagement piece 76 is broken at the break portion 72.

As a result, as shown in FIG.
The pretensioning shaft 26 is used for the drive plate 8
0 and becomes rotatable relative to the drive plate 80, the torsion bar 24 is further twisted to continue the operation of the force limiter and the spool 18
Rotates in the webbing 20 pull-out direction. Then, the torsion bar 24 is torsionally deformed until the rotational force acting on the pretensioning shaft portion 26 via the spool 18 by pulling out the webbing 20 and the torsional reaction force of the torsion bar 24 are balanced.

As shown in FIG. 14A, the holding portions 7 correspond to the rotation angle of the torsion bar 24 due to the torsional deformation.
6. Pretension shaft section 26 and spool 18
(See FIG. 1 to FIG. 3) also rotates and the webbing 20 is pulled out, and acts as a force limiter to prevent the tensile load applied to the webbing 20 from exceeding a predetermined value.

When the rotational force acting on the spool 18 is large, as shown in FIG. 3, the broken ring 54 moved toward the disc 48 hits the disc 48, and the broken ring 54 No movement or rotation is performed. As a result, the rotation of the spool 18 is also stopped, so that excessive torsional deformation of the torsion bar 24 is prevented, and the torsion bar 24 is prevented from being twisted. In addition, since the rotation of the spool 18 can be stopped by rotating the ring-shaped ring 54 and hitting the disk 48 in this manner, by adjusting the initial position of the ring-shaped ring 54, the rotation of the spool The relative rotation amount of the spool 18 can be changed. Thereby, the torsion bar 2
By adjusting the amount of torsion of No. 4, the amount of webbing 20 pulled out when the force limiter is operated can be adjusted.

As described above, in the webbing take-up device 10 according to the present embodiment, when the rotational force in the webbing 20 pulling-out direction acts on the spool 18 after the drum 64 sandwiches the pretension shaft portion 26, the drum 64 Since the breaking portion 72 is broken and the pretensioning shaft portion 26 becomes rotatable relative to the drive plate 80 of the pretensioner, the torsion bar 24 is sufficiently torsionally deformed to perform the function of the force limiter. Can be.

Also, in the pretensioning operation, the vicinity of the base of the engaging piece 76 is pressed so that even if the pressing force is increased, the bending moment acting on the breaking portion 72 is reduced, and the breaking portion 72 is pressed. Is not broken.
On the other hand, in the force limiter operation, the distal end of the engaging piece 76 is pressed, so that a large pressing moment is applied to the breaking portion 72 with a small pressing force to break the breaking portion 72. Can be. For this reason, only the pulling load (release load) at the time of the force limiter operation can be reduced without reducing the pulling force on the webbing 20 at the time of operating the pretensioner.

Note that the release portion 7 is used as the release portion.
Webbing 20 with a pretensioner
Various configurations can be adopted as long as the pretensioner and the spool 18 are integrated with each other for the load of rotation in the pullout direction, and the spool 18 can be rotated relative to the pretensioner with the load of the webbing 18 in the pullout direction. . For example, instead of the break portion 72, a deformable portion that is plastically deformed or elastically deformed is formed, and the deformed portion is deformed by a shearing force or a bending force applied to the engaging piece 76, and the webbing 20 is pulled out by the pretensioner. May be released so that the pretensioning shaft portion 26 is rotatable relative to the drive plate 80 of the pretensioner. Instead of the engagement piece 76, a gear is formed that engages with the outer periphery of the drum 64 and the inner periphery of the insertion hole 82 of the drive plate 80, and this gear is crushed, so that the pretension shaft portion is formed. 26 may be rotatable relative to the drive plate 80. Further, a clutch, a friction plate or the like may be used.

The energy absorbing member is not limited to the above-mentioned torsion bar 24, but may be deformed by the rotation of the spool 18 in the direction in which the webbing 20 is pulled out, or may be moved by causing a viscous fluid having caused friction to flow. Any material that absorbs energy and prevents an increase in the tension of the webbing 20 may be used. For example, the webbing 20 may be moved in the axial direction of the spool 18 by the rotation of the spool 18, and the movement may receive resistance due to deformation, friction, or the like, thereby preventing the tension of the webbing 20 from increasing. In addition, these energy absorbing members
It does not have to be coaxial with the spool 18.

Further, in the above description, when a deceleration equal to or more than a predetermined value is detected, the spool
Although a lock portion that locks the rotation of the spool 18 and allows rotation only in the winding direction of the webbing 20 is provided at the other end of the spool 18, this lock portion is not necessarily required. Webbing 2
After the 0 is mounted, the rotation of the spool 18 in the pulling-out direction may be locked, and the rotation of the webbing 20 may be allowed only in the winding direction. Further, if the rotation of the spool 18 can be locked, it is not necessary to be provided at the other end of the spool 18 and it is sufficient that the spool 18 is attached to the spool 18 via an energy absorbing member.

In addition, in the above description, the torsion bar 2
4 rotates with the spool via a pretension shaft portion 26 attached to one end of the spool 18, but the torsion bar 24, the spool 18
The connection structure of the pretension shaft portion 26 is not limited to this, and the pretension shaft portion 26 or the pretensioner is connected to the spool 18, and the torsion bar 24 is attached to the spool 18 separately from this. Just do it. For example, the torsion bar 24 may be attached to the other end of the spool 18 and rotate together with the spool 18.

In the pretensioning operation at the time of rapid deceleration of the vehicle, the stopper plate 96 pushes the engaging piece 76 at the position where the drive plate 80 rotated in the winding direction of the webbing 20 presses the drum 64 or during the force limiter operation. The pressing position is not necessarily limited to the above-described positions (near the root and the front end of the engagement piece 76), and these positions are determined in a relative relationship. That is, if the position at which the drive plate 80 presses the drum 64 during the pretension operation is closer to the breaking portion 72 than the position at which the stopper plate 96 presses the engagement piece 76 during the force limiter operation, the pretension operation breaks. The bending moment acting on the portion 72 can be made smaller than the bending moment acting on the break portion 72 during the operation of the force limiter. For this reason, it is possible to set the strength of the breaking portion 72 so that it is not broken by the bending moment acting in the pretension operation, but is broken by the bending moment acting in the middle of the force limiter operation. If such a condition is satisfied, the projecting direction of the engaging piece 76 is not limited to the radially outer side of the drum 64, and may be, for example, projecting in the axial direction of the drum 64.

[0064]

According to the first aspect of the present invention, when the webbing is wound around the spool and the webbing pull-out direction rotational force acts on the spool during rapid deceleration of the vehicle, the spool is deformed by the spool to increase the webbing tension. An energy absorbing member for preventing, a rotating member rotating in the webbing winding direction when a deceleration of a predetermined value or more acts, and a rotatable member integrally rotatable with the rotating member. A connecting member that is connected to the connecting member, the connecting member protruding from the connecting member, and when the rotating member rotates in the webbing winding direction, the rotating member presses the vicinity of the root, and the connecting member rotates the spool in the webbing extracting direction. When receiving and rotating, a pretensioner provided with an engagement piece that is pressed against a portion closer to the tip end than near the root, When the energy absorbing member is deformed by the rotational force in the ebbing pull-out direction and a portion of the engagement piece closer to the tip end than the vicinity of the base is pressed by the rotatable member, it receives the rotational force in the webbing pull-out direction, and Since there is provided a release portion for releasing the rotation of the webbing in the pulling-out direction by the tensioner, it is possible to reduce only the tensile load at the time of operating the force limiter without reducing the tensile force at the time of operating the pretensioner.

According to a second aspect of the present invention, in the first aspect of the present invention, the release portion is formed at a root portion of the engagement piece, and the rotating member presses the vicinity of the root of the engagement piece. When the rotating member is rotated in the webbing winding direction, the broken portion is broken. When the connecting member rotates by receiving the rotational force in the webbing pull-out direction of the spool, the breaking portion is broken, and the pulling force at the time of the force limiter operation is reduced without reducing the pulling force at the time of operating the pretensioner. Can only be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a webbing retractor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the webbing take-up device according to the embodiment of the present invention, taken along a plane including a shaft.

FIG. 3 is a cross-sectional view showing a state where the webbing is pulled out from the state shown in FIG. 2;

FIG. 4 is a perspective view showing a drum of the webbing take-up device according to one embodiment of the present invention.

FIG. 5A is a side view showing a main part of a webbing take-up device according to one embodiment of the present invention, and FIG. 5B is a cylinder of the webbing take-up device according to one embodiment of the present invention. FIG.

6 (A) is a side view of a main part showing a state where the drum has bitten into a pretensioning shaft part from FIG. 5 (A), and FIG. 6 (B) is a sectional view showing a cylinder at this time. .

7A is a side view of a main part showing a state where the drive plate has been rotated in the webbing winding direction from FIG. 6A, and FIG. 7B is a cross-sectional view showing the cylinder at this time. .

8 (A) is a side view of a main part showing a state where the drive plate has been rotated in the webbing winding direction from FIG. 7 (A), and FIG. 8 (B) is a sectional view showing a cylinder at this time. .

9A is a side view of a main part showing a state where the drive plate has been rotated in the webbing winding direction from FIG. 8A, and FIG. 9B is a sectional view showing the cylinder at this time. .

10A is a side view of a main part showing a state where the drive plate has been rotated in the webbing pull-out direction from FIG. 9A, and FIG. 10B is a cross-sectional view showing the cylinder at this time.

11A is a side view of a main part showing a state where the drive plate has been rotated in the webbing withdrawing direction from FIG. 10A, and FIG. 11B is a cross-sectional view showing the cylinder at this time.

FIG. 12A is a side view of a main part showing a state in which the drive plate is rotated in the webbing withdrawing direction from FIG. 11A and the broken part of the engagement piece is being broken, and FIG.
Is a sectional view showing the cylinder at this time.

13A is a side view of a main part showing a state in which the drive plate has been rotated in the webbing withdrawal direction from FIG. 12A and the broken part of the engagement piece has been broken, and FIG. It is sectional drawing which shows a cylinder at the time.

FIG. 14A is a side view of a main part showing a state where a holding portion of a drum and a shaft for pretension have been rotated in a webbing pull-out direction from FIG. 13A, and FIG.
It is sectional drawing of the cylinder at this time.

FIG. 15 is an exploded perspective view of a conventional webbing retractor.

[Explanation of symbols]

Reference Signs List 10 webbing take-up device 18 spool 22 torsion part 24 torsion bar (energy absorbing member) 26 pretension shaft part 40 locking shaft part 64 drum (connection member, pretensioner) 76 engagement piece (pretensioner) 76A break part ( Release section) 80 Drive plate (rotating member, pretensioner) 86 Cylinder (pretensioner) 88 Piston (pretensioner) 94 Wire (pretensioner) 96 Stopper plate (rotating member, pretensioner)

Claims (2)

[Claims] 1. A spool on which webbing is wound, an energy absorbing member which is deformed by the spool to prevent an increase in webbing tension when a rotational force in the webbing pull-out direction acts on the spool during rapid deceleration of a vehicle, and a predetermined value or more. A rotating member that rotates in the webbing winding direction when a deceleration is applied, a rotatable member integrally rotatable with the rotating member, and a connecting member that is connected to the spool when a deceleration greater than or equal to a predetermined value is applied; Projected from
When the rotating member rotates in the webbing winding direction, the vicinity of the root is pressed by the rotating member, and when the connecting member rotates by receiving the rotational force of the spool in the webbing pull-out direction, the tip is closer than the vicinity of the root. A pretensioner provided with an engaging piece pressed against the side portion, and an energy absorbing member deformed by the rotational force in the webbing pull-out direction, and the rotating member is closer to the tip side than near the base of the engaging piece by the rotating member. A webbing take-up device, comprising: a release unit that receives a rotational force in the webbing pull-out direction when a part is pressed, and releases rotation prevention in the webbing pull-out direction by the pretensioner. 2. The method according to claim 1, wherein the release portion is formed at a root portion of the engagement piece, and is not broken when the rotation member presses the vicinity of the root of the engagement piece. The webbing take-up device according to claim 1, wherein the webbing take-up device is a breakable portion that is broken when pressed.