JP2002178877A - Seat belt retractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt retractor capable of efficiently and stably absorbing energy just after pulling out a webbing. SOLUTION: This seat belt retractor is provided with winding drum 2 around which the webbing is wounded, a torsion bar united to one end portion of the winding drum 2 so as not to relatively rotate, and a ratchet wheel 5 united to the other end of the torsion bar 4 so as not to relatively rotate. The seat belt retractor is also provide with a deforming member 7 integrally formed with the other end portion of the winding drum 2, an inner teeth gear 8 provided on the torsion bar 4 so as not to relatively rotate, and a planetary gear 13 assembled to the torsion bar 4 so as not to relatively rotate by being meshed with a gear surface of the inner teeth gear 8 and engaged with the deforming member 7. When the webbing is pulled out after the actuation of an emergency lock device and the deforming member 7 and the inner teeth gear 8 are relatively rotated, the planetary gear 13 is meshed in the surface of the deforming member 7 and revolved while plastically deforming the deforming member 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy absorbing mechanism for restraining the occupant from moving forward by restraining the webbing from being pulled out at the initial stage in the event of a vehicle emergency such as a collision, thereby efficiently absorbing the energy acting on the occupant. The present invention relates to a seat belt retractor having the same.

[0002]

2. Description of the Related Art In general, a seat belt device provided in a seat of a vehicle or the like is configured such that webbing is taken up by a retractor provided with an emergency lock device. And at the time of collision, etc., the emergency lock device operates,
The webbing is prevented from being pulled out by preventing the rotation of the winding drum on which the webbing is wound, and the occupant is restrained and protected.

When the load acting on the webbing exceeds a predetermined value set in advance, the torsional deformation of the torsion bar is used to pull out the webbing under the predetermined load by a predetermined amount, thereby causing an impact to 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 Patent Laid-Open Publication No. Hei 10-310027, and comprises a substantially cylindrical winding drum on which webbing is wound, and a locking base in the event of a vehicle emergency. A structure including emergency locking means connected to a retractor base to prevent rotation of the webbing in the pulling-out direction, and energy absorbing means capable of pulling out the webbing while applying a predetermined load to the webbing after the emergency locking means is activated. It has been.

[0005] When a tension greater than a predetermined load acts on the webbing in the event of a vehicle emergency, the winding drum moves in the pulling-out direction by pulling out the webbing, and contacts the inner peripheral portion of the retractor base. With the rotation of the winding drum due to the webbing being pulled out due to the torsional deformation of the torsion bar, the outer peripheral surface of the winding drum is shaved by grinding means provided on the inner peripheral portion of the retractor base, and energy is absorbed. At the same time, the structure is such that energy is absorbed by torsion deformation of the torsion bar.

[0006]

However, according to the seat belt retractor disclosed in the above-mentioned conventional publication,
In the event of a vehicle emergency, the free end side of the winding drum supported in a cantilever manner at one end by the retractor base is moved to the inner peripheral portion and then cut by grinding means. The start of energy absorption by grinding is delayed by the time it is moved until it comes into contact with the part, and the energy absorption immediately after the start of withdrawal of the webbing is reduced. There was a risk of a subsequent collision or an increase in the impact force of the occupant on the deployed airbag.

Further, since the take-up drum has a cantilever support structure, the center of rotation of the take-up drum is of a movable structure at the free end, and the take-up drum is wound by a spring when it comes into contact with the inner peripheral portion of the retractor base. The taking drum may be separated from the inner peripheral portion, or may be deeply bitten by the grinding means.
Even in normal times, there is a risk that the take-up drum may be inadvertently moved and roughen the surface to be ground, and in such a case, there is a problem that the grinding by the grinding means is not performed constantly and stable energy absorption cannot be obtained. Was.

In view of the above problems, an object of the present invention is to provide a seat belt retractor that can efficiently and stably absorb energy immediately after the webbing is drawn.

[0009]

Technical means for achieving the above object include a winding drum on which a webbing is wound and which is urged to rotate in the winding direction, and which is inserted into the winding drum. A torsion bar whose one end is relatively non-rotatably coupled to one end of the winding drum, a ratchet wheel which is relatively non-rotatably coupled to the other end of the torsion bar, and a ratchet wheel which rotates in the event of a vehicle emergency. An emergency lock device that prevents rotation of the take-up drum in the webbing pull-out direction, wherein the torsion bar is twisted and deformed when the webbing is further pulled out after the emergency lock device is actuated. A cylindrical solar body provided at the other end of the winding drum and rotating integrally with the winding drum; and a torsion bar near the other end of the torsion bar. A bar and an internal tooth body which is provided so as to be relatively non-rotatable and has an inner peripheral surface facing away from the outer peripheral surface of the solar body; Is formed as a gear surface and the other is formed of a deformable member, and at least one planetary gear set so as not to rotate relative to the torsion bar is engaged with the gear surface and engaged with the deformable member opposed thereto. When the webbing is pulled out after the operation of the emergency lock device and the sun body and the internal tooth body are relatively rotated, the planetary gear is revolved while biting into the surface of the deformable member and plastically deforming. .

The planetary gear may have a structure in which the depth of engagement of the planetary gear with the deformable member is shorter than the gap length from the surface of the deformable member to the root of the teeth of the planetary gear.

Further, a structure may be employed in which a deformable member is formed so that the deformation allowance of the plastic deformation is gradually reduced along the moving direction of the planetary gear from the mounting position of the planetary gear in the deformable member.

A positioning pin is provided on the deformable member, and an engaging hole is provided for engaging the positioning pin in an assembled state with the one sun body or the internal tooth body having the gear surface. It is good also as a given structure.

Further, each of the teeth of the planetary gear may be formed in a trapezoidal shape whose width is gradually narrowed from the root of the tooth toward the tooth tip.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 5, a seat belt retractor 1 is made of an aluminum sheet on which webbing is wound. A winding drum 2 made of a material is provided, and has a flange portion 2a formed to protrude in the radial direction at both ends in the axial center direction. One flange 2a
A coupling body 3 made of a steel material having a prismatic support shaft portion 3a on one side and a spline concave portion 3b on the other side is press-fitted and fixed to the coupling hole 2b formed in the above.

Then, a torsion bar (torsion bar) 4 is inserted into the take-up drum 2 and a spline portion 4a provided at one end thereof is spline-coupled to the spline recess 3b. The drum 2 and one end are connected to each other so that they cannot rotate relative to each other. Further, a ratchet wheel 5 made of a steel material is press-fitted and fixed to the other end of the torsion bar 4 so that they cannot rotate relative to each other.

A cylindrical concentric spline shaft portion 2c is integrally formed on the outer surface of the flange portion 2a at the other end of the winding drum 2 to form a cylindrical solar body deformable member 7 made of aluminum. The formed spline hole portion 7c is spline-coupled to the spline shaft portion 2c.
An internal gear 8 as an internal tooth body having an internal peripheral surface facing away from the external peripheral surface of the internal gear is disposed. This internal gear 8 is
A supporting side wall 8b formed of a steel material and having a spline hole 8a on one side is provided, and the spline hole 8a of the supporting side wall 8b is formed on the shaft 5 of the ratchet wheel 5.
a is spline-coupled to a spline portion 5b formed at the position a. Here, the torsion bar 4 and the internal gear 8 are connected to each other such that they cannot rotate relative to each other.

The deformable member 7 opposed to the support side wall 8b
The pair of positioning pins 1 are spaced apart in the circumferential direction
0 are protruded integrally, and engagement holes 11 are formed at corresponding positions of the support side wall 8b so that the respective positioning pins 10 can be detachably engaged in the assembled state.

Further, a planetary gear 13 made of a pair of steel materials is mounted between the outer peripheral surface of the deformable member 7 and the gear surface of the inner peripheral surface of the internal gear 8. At this time, each of the planetary gears 13 is meshed with the gear surface of the internal gear 8, and is also meshed with the tooth portions 7 a formed at two radially separated positions on the outer peripheral surface of the deformable member 7. I have. In addition, each tooth 7
The non-teeth portion 7b of the outer peripheral surface of the deformable member 7 and the teeth 13a of the planetary gear 13 on both sides of the planetary gear 13 do not mesh with each other,
In the assembled state of each planet gear 13, each planet gear 13
Are configured so that they cannot rotate relative to the torsion bar 4.

A back plate 15a fixed to the vehicle body and a pair of side plates 15 extending from both side edges thereof so as to face each other.
The take-up drum 2 and the torsion bar 4 and the like in which the respective planetary gears 13 are assembled are rotatably supported by a housing body 15 having a substantially U-shape in plan view provided with a b.

That is, as shown in FIG.
At one end thereof, the support shaft portion 3a of the combined body 3 is
The shaft 5a of the ratchet wheel 5 is rotatably supported on the other side plate of the winding drum 2 at the other end of the winding drum 2 so as to be relatively non-rotatable. At this time, the other end of the winding drum 2 is also supported by the support shaft 5c of the ratchet wheel 5.

A spiral spring 18 is mounted on a take-up shaft 17 supported on one side plate 15b.
7 is constantly biased in the webbing winding direction.
Also, on the other side plate 15b, in the event of a vehicle emergency such as a collision,
An emergency lock device (not shown) is provided with a pawl 19 that removably engages with the ratchet wheel 5 located on the outer surface of the side plate 15b and prevents rotation of the ratchet wheel 5.

As an emergency lock device that operates by detecting acceleration or abnormal inclination applied to the vehicle body in such a collision or the like, Japanese Unexamined Utility Model Publication No. 5-78658 and Japanese Unexamined Utility Model Application Publication No.
A conventionally known structure disclosed in Japanese Patent No. 27384, Japanese Patent Application Laid-Open No. 10-138869, or the like may be appropriately employed.

Then, in the event of a vehicle emergency due to a collision or the like, the emergency lock device is activated and the pawl 19 is
, The rotation of the ratchet wheel 5 is blocked, the rotation of the winding drum 2 is blocked, and the rotation of the webbing wound around the winding drum 2 in the pull-out direction is blocked.

Further, when a tension equal to or more than a predetermined load acts on the webbing after the operation of the emergency lock device, one end of the torsion bar 4 rotates integrally with the winding drum 2 which is connected to the webbing so as not to rotate relatively. Since the other end of the torsion bar 4 does not rotate in the webbing pull-out direction due to the emergency locking device, the torsion bar 4 is twisted and deformed as the winding drum 2 rotates. Here, torsion bar 4
The webbing is pulled out while being torsionally deformed and absorbing the load.

On the other hand, at the same time as the rotation of the winding drum 2 starts, that is, the torsion bar 4 is twisted,
Each of the positioning pins 10 is sheared so that the deformable member 7 formed at the other end of the winding drum 2 rotates together with the winding drum 2 and the internal gear 8 that cannot be rotated by the emergency lock device. Relative rotation.

The relative rotation between the deformable member 7 and the internal gear 8 causes the planetary gear 13 meshing with the gear surface of the internal gear 8 to rotate.
Rolls, moves from the toothed portion 7a with which the deformable member 7 is engaged to the position of the non-toothed portion 7b on the outer peripheral surface, and sequentially meshes to deform the deformable member 7 plastically.

At this time, as shown in FIG.
Of the planetary gear 13 with respect to the
Is smaller than the gap length S from the surface of the non-tooth portion 7b to the root of the tooth 13a of the planetary gear 13, when the planetary gear 13 sequentially bites into the non-tooth portion 7b of the deformable member 7, Uneven thickness generated at the time of plastic deformation can be sufficiently ensured in the gap, and plastic deformation of the deformable member 7 due to biting is smoothly performed.

The deformation member 7 is formed integrally with the winding drum 2, and both ends of the winding drum 2 are always supported by the respective side plates 15b via the support shaft 3a and the ratchet wheel 5, respectively. Therefore, when the webbing is pulled out, the rotation center of the winding drum 2, that is, the deformation member 7 does not shift, and the energy absorption due to the plastic deformation of the deformation member 7 can be started from the initial stage of the webbing drawing.

When the webbing is pulled out from the initial state shown in FIG. 6, the deformable member 7 and the internal gear 8 rotate relative to each other with the rotation of the winding drum 2, and are shown in FIGS. As described above, each planetary gear 13 rolls while engaging with the gear surface of the internal gear 8, revolves around the outer periphery of the deformable member 7, and sequentially meshes with the non-teeth portion 7 b of the deformable member 7 to plastically deform the deformable member 7. I will transform it. At the same time, since the torsion bar 4 is torsionally deformed, as shown in FIG. 9, when each planetary gear 13 finishes cutting the teeth of the deformation member 7 by plastic deformation, thereafter, only the torsion bar 4 is torsionally deformed. .

As described above, when a tension equal to or more than a predetermined load acts on the webbing, the torsional deformation of the torsion bar 4 and the plastic deformation of the deformable member 7 can be simultaneously started in the assembled state, and the webbing can be started. Immediately after the start of drawing, the webbing is drawn while receiving a larger load. Therefore, a high load can be applied immediately after the webbing is pulled out, so that energy can be efficiently absorbed, restraining the webbing from being pulled out, reducing the forward movement of the occupant, and effectively reducing the impact force of the occupant on the airbag. Can be suppressed.

Further, the axial center of the winding drum 2 does not move, the meshing between the planetary gear 13 and the internal gear 8 and the deformable member 7 is not released during the plastic deformation, and the plastic deformation of the deformable member 7 is prevented. The load can be stably applied until the operation is completed.

Further, the load applied to the webbing can be controlled by changing the gear ratio of the planetary gear 13 and the like and the material of the deformable member 7, and the amount of energy absorption can be set according to the type of vehicle. Can be easily changed.

The gap between the planetary gear 13 and the non-toothed portion 7b effectively eliminates uneven thickness during plastic deformation, and the planetary gear 13 sequentially bites into the non-toothed portion 7b on the surface of the deformable member 7. The plastic deformation at the time of going out is also obtained stably.

Further, as shown in FIG. 10, each tooth 13a of the planetary gear 13 is formed in a trapezoidal shape which gradually narrows from the root of the tooth 13a toward the tooth tip, so that the tooth 13a has the same width in the tooth tip direction. Compared to the case of a so-called rectangular tooth, there is an advantage that the plastic deformation due to the engagement of the deformable member 7 with the non-teeth portion 7b is more smoothly performed and the uneven thickness that occurs at that time is more smoothly escaped. .

Further, the positioning can be easily performed by engaging the engaging hole 11 of the internal gear 8 with the positioning pin 10 of the deformable member 7 and assembling, and the deformable member 7, the planetary gear 13 and the internal gear 8 can be easily aligned. As a unit, and assembling work becomes easy.

Further, the load of each positioning pin 10 that is sheared at the start of the plastic deformation of the deformable member 7 can be added to the initial energy absorption, and can effectively contribute to the application of a high load at the initial stage of drawing out the webbing.

FIG. 11 shows a second embodiment, in which the non-teeth portion 7b of the deformable member 7 is formed gradually deeper in the relative movement direction of the planetary gear 13 from the mounting position of the planetary gear 13. It has been.

Therefore, in this case, not only the same effects as in the first embodiment are exerted, but also the load on the webbing is the highest at the beginning of drawing the webbing, and the load on the webbing is gradually increased as the webbing is pulled out. There is also an advantage that the energy acting on the occupant can be reduced smoothly because the energy is reduced.

Although the non-tooth portion 7b is formed so as to be gradually deeper from the position where the planetary gear 13 is attached to the relative movement direction of the planetary gear 13, the deformable member 7 is shown.
The same effect can be obtained even if the radial length of the non-tooth portion 7b is gradually reduced from the mounting position of the planetary gear 13 to the relative movement direction of the planetary gear 13. Therefore, the same effect can be obtained. A similar effect can be obtained by forming the deformable member 7 so that the deformation allowance of the plastic deformation of the non-teeth portion 7b gradually decreases along the moving direction of the planetary gear 13 from the assembling position.

FIG. 12 shows a third embodiment, in which a single planetary gear 13 is shown. And
In this case, the same effect as in the first embodiment can be obtained.

As described above, the number of the planetary gears 13 is one or two.
The number is not limited to an individual number, and may be appropriately determined according to the initial energy absorption amount.

Further, a structure in which the deformable member 7 is formed integrally with the winding drum 2 may be adopted.

In each of the above embodiments, the structure in which the sun body is the deformable member 7 is shown, but the sun body is a sun gear meshing with the planetary gear 13 and the internal teeth body is the deformable member. You may.

[0044]

As described above, according to the seat belt retractor of the present invention, the cylindrical solar body provided at the other end of the winding drum and integrally rotating with the winding drum,
An inner tooth body provided near the other end of the torsion bar so as to be relatively non-rotatable with the torsion bar and having an inner peripheral surface facing away from the outer peripheral surface of the solar body; One of the inner peripheral surfaces is a gear surface and the other is a deformable member, and at least one planetary gear set to be non-rotatable relative to the torsion bar is meshed with the gear surface and faces a deformable member. When the webbing is pulled out and the sun body and the internal teeth body are rotated relative to each other after the emergency lock device is actuated, the planetary gear is revolved while biting into the surface of the deformable member and plastically deforming. When a tension greater than a predetermined load acts on the webbing, it is possible to simultaneously start the torsional deformation of the torsion bar and the plastic deformation of the deformable member in the assembled state. Drawer start immediately after the webbing,
The webbing is pulled out while receiving a larger load, and a high load can be applied immediately after the webbing is pulled out, so that energy can be efficiently absorbed, webbing pulling out can be suppressed, and the occupant's forward movement can be reduced. This has the advantage that the occupant can be prevented from colliding with the steering wheel or the instrument panel, and the impact force of the occupant on the airbag can be effectively suppressed.

Further, the axial center of the winding drum does not move, the engagement between the planetary gear and the internal teeth body and the sun body is not released during the plastic deformation, and the webbing is applied until the plastic deformation of the deformable member is completed. There is an advantage that a load can be applied stably.

Further, the load applied to the webbing can be controlled by changing the gear ratio of a planetary gear or the like or the material of the deformable member, and the energy absorption amount can be easily set according to the type of vehicle. There is also the advantage that it can be changed.

If the depth of engagement of the planetary gear with the deformable member is shorter than the length of the gap from the surface of the deformable member to the root of the teeth of the planetary gear, the planetary gear and the surface of the deformable member can be removed. There is an advantage that the uneven thickness at the time of plastic deformation is effectively evacuated due to the gap between them, and the plastic deformation when the planetary gears sequentially bite into the surface of the deformable member can be stably obtained.

Further, if the deformation member is formed so that the deformation allowance of the plastic deformation is gradually reduced from the mounting position of the planet gear in the deformation member in the moving direction of the planet gear, the webbing is drawn out. Since the load on the webbing is highest at the beginning of the start and the load on the webbing gradually decreases as the webbing is pulled out, there is an advantage that the energy acting on the occupant can be reduced smoothly.

Further, if the structure is such that a positioning pin is projected from the deformable member and an engaging hole is provided for engaging the positioning pin in an assembled state with the sun body or the internal tooth body having a gear surface, At the same time, the sun body, planetary gears and internal teeth can be handled as a unit, and the load of each positioning pin that is sheared at the start of plastic deformation of the deformable member can be added to the initial energy absorption. There is an advantage that it can effectively contribute to the application of a high load in the initial stage of drawing.

Furthermore, if each tooth of the planetary gear is formed in a trapezoidal shape that gradually narrows from the root of the tooth to the tip of the tooth, plastic deformation due to biting into the surface of the deformable member can be performed more smoothly. In addition, there is an advantage that the deviation of the uneven thickness generated at that time can be smoothly performed.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is an exploded perspective view of the same.

FIG. 4 is an exploded perspective view of the same.

FIG. 5 is an enlarged explanatory view of a main part.

FIG. 6 is an operation explanatory diagram.

FIG. 7 is an operation explanatory diagram.

FIG. 8 is an operation explanatory diagram.

FIG. 9 is an operation explanatory diagram.

FIG. 10 is a front view of the planetary gear.

FIG. 11 is an enlarged explanatory view of a main part showing a second embodiment.

FIG. 12 is an exploded perspective view of a main part showing a third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 seat belt retractor 2 winding drum 3 coupling body 4 torsion bar 5 ratchet wheel 7 deformable member 8 internal gear 10 positioning pin 11 engagement hole 13 planetary gear

Claims (5)

[Claims] 1. A winding drum on which webbing is wound and urged to rotate in the winding direction, and one end of which is inserted into the winding drum and whose one end cannot rotate relative to one end of the winding drum. A torsion bar connected to the torsion bar, a ratchet wheel connected to the other end of the torsion bar so as to be relatively non-rotatable,
An emergency lock device for preventing rotation of the ratchet wheel in the event of a vehicle emergency and preventing rotation of the winding drum in the webbing withdrawal direction. When the webbing is further pulled out after the emergency lock device is operated, the torsion bar is twisted and deformed. In the seat belt retractor, a cylindrical solar body that is provided at the other end of the winding drum and rotates integrally with the winding drum, and is provided near the other end of the torsion bar so as not to rotate relative to the torsion bar. And an internal tooth body having an inner peripheral surface facing away from the outer peripheral surface of the solar body, and one of the outer peripheral surface of the solar body or the inner peripheral surface of the internal tooth body is a gear surface. The other is formed of a deformable member, and at least one planetary gear set to be incapable of rotating relative to the torsion bar is meshed with and opposed to the gear surface When the webbing is pulled out and the sun body and the internal tooth body are rotated relative to each other after the emergency lock device is operated, the planetary gear bites into the surface of the deformable member. A seat belt retractor that revolves around while plastically deforming. 2. The seat according to claim 1, wherein a depth of engagement of the planetary gear with the deformable member is shorter than a gap length from a surface of the deformable member to a root of a tooth of the planetary gear. Belt retractor. 3. The deformable member is formed such that a deformation allowance of the plastic deformation is gradually reduced from a position where the planetary gear is mounted on the deformable member in a moving direction of the planetary gear. 3. The retractor for a seat belt according to 1 or 2. 4. A positioning pin is projected from said deformable member, and an engagement hole is provided for engaging said positioning pin in an assembled state with said one sun body or said internal tooth body having said gear surface. The retractor for a seat belt according to claim 1, 2 or 3, wherein the retractor is provided. 5. The seat belt according to claim 1, wherein each of the teeth of the planetary gear is formed in a trapezoidal shape that gradually narrows in a direction from the root of the tooth to the tooth tip. For retractor.