JP2003341474A - Retractor for seat belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retractor for a seat belt capable of preventing the belt from hopping out of the retractor and simplifying its structure. <P>SOLUTION: The retractor for the seat belt is equipped with a torsion bar coupled wit one end of a takeup drum in such a way as not capable of making relative rotation, a plate 8 having a takeup part 12 in proximity to the side face of the other end of the takeup drum and coupled with the other end of the torsion bar in such a way as not capable of making relative rotation, and a wire whose one end is attached to the plate 8 and middle part is arranged along a bending path provided on the side face of the other end of the takeup drum. The plate 8 is furnished with a guide taper part 14 for shifting the wire wound round the takeup part 12 of the plate 8 in the axial direction of the takeup part 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt retractor having an energy absorbing mechanism for restraining the movement of an occupant by restraining the withdrawal of the webbing at the initial stage in an emergency of a vehicle and absorbing the energy acting on the occupant. It is about.

[0002]

2. Description of the Related Art Generally, a seat belt device provided in a seat of a vehicle or the like has a structure in which a webbing is wound around a retractor having an emergency lock mechanism. In the event of a collision, etc., the emergency lock mechanism is activated by sensing the change in acceleration due to the impact force, and the webbing is prevented from rotating by blocking the rotation of the take-up drum. It is designed to be restrained and protected.

Further, when the pulling force acting on the webbing exceeds a predetermined value set in advance, the torsional deformation of the torsion bar or the like is utilized to pull out the webbing under a predetermined load to cause an impact on the occupant. A seat belt retractor having an energy absorbing mechanism for absorbing energy has also been proposed.

A seat belt retractor of this type is disclosed, for example, in Japanese Utility Model Laid-Open No. 56-19245, in which a retractor shaft is rotatably provided on a retractor body to wind a seat belt (webbing). A gear member driven by the winding shaft and a restraining means for preventing rotation of the gear member in the event of a vehicle collision, and the gear member has a winding member having one end fixed to the winding shaft and a winding member. The structure is provided with a storage case having gear means that can be coupled to the restraining means, and an ironing pin around which a winding material is wound in a U shape.

When the restraint means is activated at the time of collision of the vehicle and the pulling force of a predetermined value or more acts on the seat belt, the winding shaft rotates while winding the winding material. At this time, the winding material accommodated in the storage case in which the rotation is blocked is sequentially wound around the winding shaft while being squeezed by the ironing pin, and a predetermined load is applied to the seat belt at this position. It was designed to allow withdrawal and absorb impact energy.

[0006]

However, according to the structure disclosed in the above-mentioned prior art publication, the take-up shaft is moved in the axial direction as the take-up shaft rotates, so that the take-up materials are overlapped. The retractor main body needs to be large in size because the take-up shaft pops out of the retractor main body due to the axial movement of the take-up shaft.

Further, the structure is such that the winding shaft is moved in the axial direction, the arrangement relationship of other members and the like is complicated, and there is a drawback that the structure is complicated.

In view of the above-mentioned problems, it is an object of the present invention to provide a seat belt retractor having a simplified structure without protruding from the retractor to the outside.

[0009]

[Means for Solving the Problems] The technical means for achieving the above-mentioned object is to provide a winding drum around which a webbing is wound, and one end of the winding drum fitted into the winding drum. A torsion bar that is relatively non-rotatably coupled to the web and is biased to rotate in the webbing winding direction; and an emergency lock mechanism that operates in a vehicle emergency to prevent rotation of the other end of the torsion bar in the webbing pull-out direction. A plate body having a winding portion adjacent to the side surface of the other end of the winding drum and coupled to the other end of the torsion bar in a relatively non-rotatable manner;
One end is attached to the plate body, and an intermediate portion thereof is provided with a wire arranged along a bending path provided on the side surface of the other end portion of the winding drum, and a predetermined value or more after the emergency lock mechanism operates in an emergency of the vehicle. When the pulling force of the acts on the webbing, the torsion bar is twisted and deformed, and the relative rotation between the plate body and the winding drum causes the wire to be wound around the winding portion, and the wire is wound from the bent path. Under impact energy absorption by the pull-out resistance to be pulled out, in a seat belt retractor in which the webbing can be pulled out, the wire wound around the winding portion of the plate body is displaced in the axial direction of the winding portion. The guide taper portion for shifting the position is provided on the plate body.

Further, the guide taper portion may be provided so as to correspond to a position just before the wire wound around the winding portion finishes the first round.

Further, the edge portion of the guide taper portion located on the rear side with respect to the winding direction in which the wire is wound is displaced in position so that the wire is displaced in the axial direction of the winding portion by the guide taper portion. The structure may be an inclined guide surface that inclines in the front direction of the winding direction from the rear end to the front end in the direction.

Further, the winding portion around which the wire is wound may be formed so that the outer diameter of the winding portion is gradually reduced from the start of winding.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 9, a seat belt retractor is made of an aluminum material around which a webbing is wound. A winding drum 2 formed of the same or the like, and has flange portions 2a and 2b that are formed to extend in the radial direction at both ends in the axial direction, and are formed on the side of one flange portion 2a. The joint body 3 made of a steel material or the like is press-fitted and fixed in the joint hole portion so as not to be relatively rotatable.

Then, the torsion bar 4 constituting the first energy absorbing mechanism is fitted and inserted in the winding drum 2,
One end of the torsion bar 4 and the winding drum 2 are spline-coupled to the joint body 3 which is press-fitted and fixed, and the torsion bar 4 and the winding drum 2 are joined to each other at one end so that they cannot rotate relative to each other.

A ratchet wheel 5, which constitutes one part of an emergency lock mechanism for preventing the seat belt from being pulled out in an emergency such as a vehicle collision, is spline-coupled to the other end of the torsion bar 4.

A housing body 6 for rotatably supporting the winding drum 2 is provided with a back plate 6a fixed to the vehicle body and side plates 6b extending from opposite side edges thereof so as to face each other. The winding drum 2 is formed in a U shape and is rotatably supported between both side plates 6b.

That is, at one end of the take-up drum 2, the combined body 3 connected and fixed to the take-up drum 2 is penetrated through the through hole formed in the one side plate 6b, and the support structure is appropriately interposed. It is structured to be rotatably supported. Further, the other end of the winding drum 2 is rotatable by appropriately supporting a torsion bar 4 penetrating through a through hole formed in the other side plate 6b via a support structure. The structure is supported by.

As disclosed in Japanese Unexamined Patent Publication No. 2002-53007, one side plate 6b is always engaged with the combined body 3 to constantly urge the take-up drum 2 in the webbing take-up direction. It is provided with a spring collecting mechanism and a pretensioner mechanism that engages the coupling body 3 in the emergency of the vehicle to rotate the winding drum 2 in the winding direction and removes looseness of the webbing. The structure is provided with an emergency lock mechanism in which a lock pawl (not shown) is engaged with the ratchet wheel 5 to prevent rotation in the webbing pull-out direction.

An example of such an emergency lock mechanism is the utility model registration No. 2574 by the applicant of the present application.
The conventional mechanism disclosed in Japanese Patent No. 488, etc. may be appropriately adopted, and the winding spring mechanism and the pretensioner mechanism may be appropriately adopted.

The other flange portion 2 of the winding drum 2
A second energy absorbing mechanism is provided between the b and the ratchet wheel 5, and the second energy absorbing mechanism is connected to the other end of the torsion bar 4 with a plate body 8 which is relatively non-rotatably coupled. The wire 9 is provided between the other flange portion 2b of the winding drum 2 and the plate body 8 and has a wire 9 made of a metal material such as stainless steel and having an appropriate length.

That is, the plate body 8 is formed in a substantially circular thin plate shape, and the spline hole portion 8a formed at the center thereof.
In addition, the spline shaft portion 5a of the ratchet wheel 5 spline-coupled to the torsion bar 4 is spline-coupled so that the torsion bar 4 and the plate body 8 are coupled to each other such that they cannot rotate relative to each other.

As shown in FIGS. 5 to 9, a bending path 10 for holding one end of the wire 9 is provided on the outer peripheral portion of the facing surface of the plate body 8 which faces the flange portion 2b of the winding drum 2.
To form a plurality of convex portions 11 and a winding portion 1 in which the wire 9 is wound along the circumferential direction.
2 are integrally formed.

In addition, as shown in FIG.
As shown in FIG.
Ribs 13 provided along the depth direction of the
The distance is smaller than the outer diameter of the wire 9.

Further, on the outer peripheral edge side of the plate body 8 of each convex portion 11 located on the outer peripheral edge portion of the plate body 8, as shown in FIG. 8 and FIG. The guide taper portion 14 is formed in a taper shape for gradually shifting the diameter of 12 so as to be displaced in the axial direction, and the guide taper portion 14 for position shifting is formed.

The end portion of the guide taper portion 14 for position shifting, which is located on the rear side with respect to the winding direction P (see FIG. 5) around which the wire 9 is wound, is wound by the guide taper portion 14. The rear end A with respect to the position shifting direction Q (see FIG. 6) in which the grip portion 12 is displaced in the axial direction
Is formed as an inclined guide surface 14a that inclines in the front direction of the winding direction P from the front to the front end B.

The winding drum 2 facing the plate body 8
As shown in FIGS. 1 to 3, the flange portion 2b is provided with an accommodating concave portion 15 for accommodating the respective convex portions 11 and the winding portion 12 formed on the plate body 8, and at the outer peripheral portion thereof. A bent path 17 through which the wire 9 is slidably guided is formed by the plurality of integrally formed convex portions 16.

At this time, the projections 16 are provided at five locations, the wire 9 drawn out from the bent path 17 is drawn inward with respect to the radial direction, and the radius of curvature of the bent path 10 in the plate body 8 is changed. , Curved path 1 at flange 2b
The structure is smaller than the radius of curvature of 7.

The bent portion at one end of the wire 9 is accommodated and held in the bent path 10 of the plate body 8, and the bent portion at the middle portion of the wire 9 is arranged along the bent path 17 in the flange portion 2b of the winding drum 2. In this state, each convex portion 11 of the plate body 8 and the winding portion 12 are accommodated in the accommodation concave portion 15 of the flange portion 2b.
Are accommodated and arranged, and the assembled state is maintained by the retainer 18 formed of resin or the like.

That is, a plurality of locking holes 18a are formed on the outer peripheral portion of the retainer 18 in a circumferentially spaced manner, and locking protrusions 2c are formed on the outer peripheral surface of the corresponding flange portion 2b, respectively. The retainer 18 is attached to the flange portion 2b by locking the locking protrusions 2c in the locking holes 18a of the retainer 18.

Further, a guide taper portion 14 for displacing the position is provided on the winding portion 12 on the outer peripheral side of the plate body 8 of the convex portion 11 which constitutes the bent path 10 in which one end of the wire 9 is accommodated and held.
The wire 9 wound around is provided at a position immediately before the end of the first round.

The present embodiment is configured as described above, and its operation will be described. When a normal seat belt is used, when the webbing is pulled out or taken up, the winding bar 2 and the plate together with the torsion bar 4 are used. The body 8 is rotated integrally.

When the emergency lock mechanism is activated in a vehicle emergency such as a collision, the ratchet wheel 5 is prevented from rotating in the webbing pull-out direction. When a load is applied to the webbing in this state and a pulling force of a predetermined value or more is applied to the webbing, one end of the torsion bar 4 opposite to the ratchet wheel 5 is rotated, and the torsional deformation of the torsion bar 4 is started. As the torsion bar 4 is twisted and deformed, the winding drum 2 rotates in the webbing pull-out direction,
The impact energy is absorbed by the torsion bar 4 as the first energy absorbing mechanism.

At this time, since the ratchet wheel 5 and the plate body 8 are spline-fitted, the winding drum 2
And relative rotation occurs between the plate body 8 and the
The impact energy is absorbed by the second energy absorbing mechanism.

That is, in the second energy absorbing mechanism, the winding drum 2 is relatively rotated in the webbing drawing-out direction R from the initial state of the winding drum 2 and the plate body 8 shown in FIG.

Then, as the winding drum 2 rotates, as shown in FIGS. 11 and 12, the wire 9 whose one end is fixedly held by the plate body 8 is formed by the bent portions formed by the respective convex portions 16. It is pulled out from 17 while being squeezed. The wire 9 is connected to the meandering bent path 17.
When passing through while deforming, a sliding resistance is generated between each convex portion 16 and the wire 9 and a bending resistance is generated by the wire 9 itself. Is done.

Since the wire 9 wound around the winding section 12 is subjected to a force in the axial center direction of the winding section 12, the wire 9 wound around the winding section 12 is
As shown in FIG. 2, the guide taper portion 14 provided on the outer peripheral portion of the convex portion 11 causes the wire 9 to be continuously wound in the axial direction of the winding portion 12, that is, the position shifting direction Q immediately before the end of the first round. It is naturally slid and wound along the inclination of the guide taper portion 14,
Overlap of the wires 9 is prevented.

At this time, since the edge portion of the guide taper portion 14 located on the rear side of the winding direction P is also formed as the inclined guide surface 14a, the wire 9 is displaced in the direction Q in the initial sliding stage. Due to the synergistic effect of the inclined guide surface 14a and the guide taper portion 14, the wire 9 can be slid more reliably and smoothly.

Thereafter, as the winding drum 2 rotates, as shown in FIG.
At the point of departure from the above, the action of absorbing the impact energy by the second energy absorbing mechanism ends, and thereafter, only the impact energy due to the torsional deformation of the torsion bar 4 is absorbed.

As described above, when the emergency lock mechanism is activated in the event of an emergency of the vehicle and the rotation of the ratchet wheel 5 is blocked, when the webbing pulling force acts in the webbing drawing-out direction R on the webbing at a predetermined value or more, 2 rotates in the webbing pull-out direction R, and both the first energy absorbing mechanism by the torsion bar 4 and the second energy absorbing mechanism by the wire 9 or the like absorb the impact energy in the emergency of the vehicle.

Even if the wire 9 wound around the winding portion 12 has a length of one round or more, the guide taper portion 14 causes the wire 9 to slide in the axial direction of the winding portion 12, so that the wire 9 has a spiral shape. It can be smoothly wound around, and the effect of absorbing impact energy can be exerted smoothly.

Even if the length exceeds the second lap, 2
The wire 9 wound around the circumference exhibits a guide function and can be continuously wound in a spiral shape, and it becomes possible to take a long time to absorb energy, and the length of the wire 9 is adjusted to absorb energy. The amount can be adjusted easily.

Furthermore, the wire 9 wound by the guide taper portion 14 is displaced in the axial direction of the winding portion 12 to prevent the wires 9 from overlapping with each other. Since there is no protrusion of various members to the outside and the mutual positional relationship with other members etc. does not change, the positional relationship between mutual members can be easily determined, the structure can be simplified, and the structure of the retractor can be facilitated. Can be designed and manufactured.

Further, the guide taper portion 14 is provided with the winding portion 12
The wire 9 wound around the guide taper portion 14 is provided at a position immediately before the end of the first round.
In other portions other than the above, the wire 9 can be stably wound around the winding portion 12.

Further, since the inclined guide surface 14a is provided at the end edge of the guide taper portion 14, the wire 9 can be more reliably and smoothly moved in the initial stage of sliding the wire 9 in the axial direction of the winding portion 12. There is also an advantage that it can be slid in the position shifting direction Q.

Further, in the present embodiment, the bending path 10
The ribs 13 are formed on the facing surfaces of the convex portions 11 and the distance between the facing ribs 13 is smaller than the outer diameter of the wire 9. It becomes a structure in which it is clamped and fixed more firmly by 13, and it becomes difficult to pull out in the direction perpendicular to the side surface of the plate body 8, the initial setting during assembly can be stabilized, and abnormal noise due to rattling or the like is effectively generated. It can be prevented. Therefore, there is also an advantage that after the assembling, it can be easily carried and the assembling work in a later process can be performed.

14 to 16 show the plate body 8 in the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

That is, while the winding portion 12 of the plate body 8 in the first embodiment is formed in a substantially cylindrical shape protruding in the axial direction of the winding portion 12, the plate body 8 of the present embodiment is The winding portion 12 is formed in a spiral shape so that the outer diameter of the outer peripheral surface of the winding portion 12 is gradually reduced from the winding start position, and has a structure having a step in the axial direction of the winding portion 12. The wire 9 is also structured to have a length such that it can be wound around the winding section 12 a plurality of times.

The other winding drum 2 side is the first
The configuration is substantially the same as that of the above embodiment.

Therefore, according to the present embodiment, the wire 9 is sequentially wound around the winding portion 12 by the relative rotation between the winding drum 2 and the plate body 8, and the guide taper portion is immediately before the second lap. 14 and the inclined guide surface 14a,
Since it is guided to the winding portion 12 side in the position shifting direction Q that is adjacently arranged with a step, it is possible to effectively prevent the wires 9 from overlapping in the second round, and to achieve the same effect as that of the first embodiment. .

Further, in the second energy absorbing mechanism, the outer diameter of the winding portion 12 around which the wire 9 is wound is gradually reduced in a spiral shape, so that the wire 9 is wound around the winding portion 12. Along with, the convex portion 16 and the wire 9 that are located on the front side in the drawing direction of the wire 9 that constitutes the bent path 17
Since the sliding tip position of and gradually moves in the direction of the adjacent protruding portion 16 on the rear side in the drawing direction, the sliding area between the protruding portion 16 located on the front side in the drawing direction and the wire 9 gradually decreases. .

Therefore, the energy absorption characteristics due to the pull-out resistance of the wire 9 are such that the energy absorption load immediately after the wire 9 is wound around the outer peripheral surface of the winding portion 12 is large,
It is configured to gradually become smaller. On the other hand, in the characteristic of absorbing the impact energy due to the torsional deformation of the torsion bar 4 as the first energy absorbing mechanism, the energy absorption load gradually increases as the amount of torsional deformation increases.

Here, the energy absorption characteristic of the energy absorption mechanism in the present embodiment, which is a combination of both, should be as close as possible to the maximum load limit, which is the limit of the load in the range where the energy absorption load does not adversely affect the occupant. Therefore, it is possible to more efficiently perform the energy absorption in the initial stage immediately after the start of the absorption of the impact energy by the energy absorption mechanism in the emergency of the vehicle.

Further, since the winding portion 12 is formed in a spiral shape, there is an advantage that the energy absorbing action can be exhibited for a long time by winding the wire 9 a plurality of times.

Further, it has a simple structure in which the outer diameter of the winding portion 12 around which the wire 9 is wound is gradually reduced, and there is an advantage that it can be easily manufactured.

FIG. 17 shows the winding drum 2 in the third embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

That is, while the number of the convex portions 16 formed on the flange portion 2b of the winding drum 2 in the first embodiment is five, the flange portion 2b of the winding drum 2 in the present embodiment has five. The number of the convex portions 16 formed is three, and the bent path 17 is short.

Therefore, the pull-out resistance when pulling out the wire 9 arranged in the bent path 17 is made smaller, and the energy absorption load by the second energy absorbing mechanism is made smaller. Therefore, the structure according to the first embodiment may be adopted when the energy absorption load is too large and the desired maximum load limit is difficult to obtain.

The wire 9 in each of the above-mentioned embodiments.
Although stainless steel is exemplified as the material of, the material is not limited to stainless steel, and other metals such as iron and copper may be selected so that the optimum energy absorption load can be obtained according to the energy absorption characteristics of the torsion bar 4. Well, again
The outer diameter of the wire 9 may be appropriately selected such as a large diameter or a small diameter. Further, the radii of curvature of the curved paths 10 and 17 may be appropriately determined as necessary.

[0059]

As described above, according to the seat belt retractor of the present invention, the torsion bar, which is coupled to the one end of the winding drum so as not to be relatively rotatable, and the side surface of the other end of the winding drum are close to each other. A plate body having a take-up part that is fixed to the other end of the torsion bar so as not to rotate relative to the other end of the torsion bar; And a wire arranged along the path, and the plate body is provided with a guide taper portion for shifting the position of the wire wound around the winding portion of the plate body in the axial direction of the winding portion. Yes, there is no protrusion of members to the outside, and the mutual positional relationship with other members etc. does not change, so the positional relationship between mutual members can be easily determined, the structure can be simplified, and the retractor structure can be improved. To design, it can be manufactured.

Even if the wire wound around the winding portion has a length of one round or more, the guide taper portion causes the wire to slide naturally in the axial direction of the winding portion, so that the wire smoothly spirals. It can be wound around, the impact energy can be absorbed smoothly, and even if the length exceeds the second round, the wire wound around the second round exhibits the guide function and becomes a spiral shape as well. It has the advantage that it can be wound around, energy absorption time can be lengthened, and the amount of energy absorption can be easily adjusted by adjusting the length of the wire.

Furthermore, if the guide taper portion for shifting the position is provided corresponding to the position immediately before the wire wound around the winding portion finishes the first round, the guide taper portion other than the guide taper portion is provided. Has an advantage that the wire can be stably wound around the winding portion.

Further, the edge portion of the guide taper portion for position shifting, which is located on the rear side with respect to the winding direction around which the wire is wound, has a position shift where the wire is displaced by the guide taper portion in the axial direction of the winding portion. With a structure with an inclined guide surface that inclines in the front direction of the winding direction from the rear end to the front end with respect to the direction, it is more reliable and smooth at the initial stage of sliding the wire in the winding direction. There is an advantage that the wire can be slid in the displacement direction.

Further, in the structure in which the outer diameter of the winding portion around which the wire is wound is formed to be gradually reduced from the start of winding, the energy absorption load gradually increases as the amount of twist deformation increases. The energy absorption load does not adversely affect the occupant due to the combined action of the energy absorption effect of the increasing torsion bar and the energy absorption effect of the wire pull-out resistance where the energy absorption load immediately after starting is large and gradually decreases. There is an advantage that the maximum load limit, which is the limit of the load of the range, can be met as much as possible, and the energy absorption by the energy absorption mechanism in the emergency of the vehicle can be performed more efficiently.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts showing a first embodiment of the present invention.

FIG. 2 is a partially sectional front view of the same portion assembled state.

3 is a partial cross-sectional side view of FIG.

FIG. 4 is an assembly explanatory diagram of a torsion bar and a ratchet wheel.

FIG. 5 is a side view of a plate body.

FIG. 6 is a left side view of the same.

FIG. 7 is a partially enlarged view of FIG.

FIG. 8 is a sectional view taken along the line IIIV-IIIV in FIG.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is an operation explanatory diagram.

FIG. 11 is an operation explanatory diagram.

FIG. 12 is an operation explanatory diagram.

FIG. 13 is an operation explanatory diagram.

FIG. 14 is a side view of a plate body showing a second embodiment.

15 is a sectional view taken along line XV-XV in FIG.

16 is a sectional view taken along line XVI-XVI in FIG.

FIG. 17 is a perspective view of a winding drum showing a third embodiment.

[Explanation of symbols]

2 winding drum 2a, 2b Flange part 4 torsion bar 5 ratchet wheel 8 plate body 9 wires 10 Bending road 11 convex 12 winding section 13 ribs 14 Guide taper 14a inclined guide surface 15 Storage recess 16 convex 17 Bending road

Claims (4)

[Claims] 1. A winding drum around which webbing is wound,
A torsion bar, which is fitted into the winding drum and has one end coupled to one end of the winding drum in a non-rotatable manner and which is urged to rotate in the webbing winding direction, and a torsion bar which operates when the vehicle is in an emergency. A plate that has an emergency locking mechanism that prevents the other end of the roller from rotating in the webbing pull-out direction, and a winding portion that is close to the side surface of the other end of the winding drum, and that is connected to the other end of the torsion bar so as not to rotate relative to it. A body and a wire whose one end is attached to the plate body and whose middle portion is arranged along a curved path provided on the side surface of the other end of the winding drum, and after the emergency lock mechanism operates in a vehicle emergency, When a pulling force of a predetermined value or more acts on the webbing, the wire is wound around the winding portion due to the torsional deformation of the torsion bar and the relative rotation of the plate body and the winding drum. Under impact energy absorption due to pull-out resistance with which the wire is pulled out from the bent path, a seat belt retractor in which the withdrawal of the webbing is allowed, the wire wound around the winding portion of the plate body, A seatbelt retractor characterized in that the plate body is provided with a guide taper portion for shifting the position of the winding portion in the axial direction. 2. The retractor for a seat belt according to claim 1, wherein the guide taper portion is provided corresponding to a position immediately before the wire wound around the winding portion finishes the first round. . 3. An end edge portion of the guide taper portion located on a rear side with respect to a winding direction around which the wire is wound is displaced by a position where the wire is displaced by the guide taper portion in an axial direction of the winding portion. The seat belt retractor according to claim 2, wherein the seat belt retractor has an inclined guide surface that inclines in a front direction of the winding direction from a rear end to a front end with respect to the direction. 4. The seat belt according to claim 1, wherein an outer diameter of the winding portion around which the wire is wound is formed so as to be gradually reduced from the start of winding. Retractor.