JP2007126148A - Webbing take-up device with pretensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the whole device in the axial and the radial direction by abolishing an intermediate gear to be conventionally used. <P>SOLUTION: The drive mechanism of the pretensioner comprises a piston 116 which is disposed in a cylinder and moves in a sudden deceleration of a vehicle, and a pinion 102 which is directly connected with the sleeve through a clutch which is connected with the take-up shaft only in the sudden deceleration of the vehicle. The pinion is constituted as a component comprising a tooth part 104 where the pinion teeth 104A meshed with only the rack teeth, and a clutch part 106 which is coaxially and integrally formed with the tooth part, and equipped with a clutch at the inner peripheral side. The piston comprises a piston part 118 which receives gas pressure, and a rack part 120 which is vertically provided at the position offset from the center of the piston part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is integrated with a webbing take-up device that winds up an occupant-constrained webbing in a layered manner on a take-up shaft, and instantaneously rotates the take-up shaft in the direction of webbing take-up when the vehicle suddenly decelerates by a rack and pinion type drive mechanism. The present invention relates to a pretensioner that rotates a predetermined amount.

  Conventionally, a so-called pretensioner that improves occupant restraint performance by webbing by rotating a winding shaft by a predetermined amount in the webbing winding rotation direction instantaneously at the time of sudden vehicle deceleration has been used.

  Various drive mechanisms for such pretensioners have been studied and put into practical use. Hereinafter, a pretensioner using a rack and pinion type drive mechanism disclosed in Japanese Patent Laid-Open No. 7-156751 (Patent Document 1) will be described.

  In the pretensioner disclosed in this publication, a cylindrical cylinder tube is attached to a housing attached to a side portion of the webbing take-up device. A hollow piston is inserted into the cylinder tube so as to be movable in the axial direction, and an explosive and an ignition device are arranged inside the piston. Furthermore, rack teeth are formed at predetermined positions on the outer periphery of the piston along the axial direction thereof, and the piston itself functions as a rack bar.

  Further, a notch is formed at a predetermined position in the axial direction of the cylinder tube, and the pinion teeth enter the cylinder tube through this notch so as to be able to mesh with the rack teeth. A first gear having a larger diameter than that of the pinion is coaxially connected to the pinion, and a second gear meshes with the first gear. The second gear is integrated with a coupling wheel that functions as a clutch, and the second gear is connected to the shaft end of the winding shaft of the webbing winding device via the coupling wheel.

According to the above configuration, when the vehicle suddenly decelerates, the gunpowder is ignited by the ignition device, and the piston (rack bar) moves axially in the cylinder pipe by the ignition thrust at that time. As a result, the pinion meshing with the rack teeth of the piston rotates about its axis, thereby rotating the first gear and the second gear. Since the coupling coupled to the shaft end of the winding shaft is integrated with the second gear, when the second gear rotates, the winding shaft is rotated in the webbing winding direction via the coupling.
Japanese Patent Laid-Open No. 7-156751

  However, in the case of the above configuration, the pretensioner is not only a pinion but also an intermediate gear such as the first gear and the second gear between the piston (rack bar) serving as the driving start point and the winding shaft serving as the driving end point. The installation space for these intermediate gears must be secured in the housing. For this reason, there exists a problem that a pretensioner becomes large in radial direction and an axial direction as a whole.

  An object of the present invention is to obtain a pretensioner capable of downsizing the entire apparatus in consideration of the above facts.

  The present invention as claimed in claim 1 is integrated with a webbing take-up device for taking up an occupant-constrained webbing on a take-up shaft and instantaneously winds the take-up shaft by a rack-and-pinion type drive mechanism when the vehicle suddenly decelerates. A webbing take-up device with a pretensioner that rotates a predetermined amount in the take-off rotation direction, wherein the drive mechanism is disposed in the cylinder so as to be movable in the axial direction, and moves when the vehicle suddenly decelerates, and rack teeth of the piston And a pinion that is directly connected to the take-up shaft via a clutch that is connected to the take-up shaft only when the vehicle suddenly decelerates. The pinion only meshes with the rack teeth. A tooth part formed with pinion teeth and a clutch part coaxially and integrally formed with the tooth part and provided with the clutch on the inner peripheral side are configured as one part. The piston includes a piston portion and a rack portion standing at a position offset from the center of the piston portion, and the outer shape of the rack portion as viewed in the axial direction of the piston is It is characterized in that at least the corners of the rack teeth are chamfered so as not to protrude from the outer shape of the piston part.

  According to a second aspect of the present invention, in the first aspect of the present invention, the rack teeth formed on the rack portion of the piston are different from the pinion teeth formed on the tooth portion of the pinion before the pretensioner operates. The rack teeth are arranged apart from each other, and the rack teeth mesh with the pinion teeth when the piston moves in the axial direction by operation of a pretensioner.

  As described above, the pretensioner according to the first and second aspects of the present invention can eliminate the intermediate gear conventionally used, and as a result, the entire apparatus can be reduced in the axial direction and the radial direction. It has an excellent effect of being able to

  Hereinafter, the webbing retractor 10 in which the pretensioner 100 according to the embodiment of the present invention is integrated will be described with reference to FIGS.

  First, the spool 12 of the webbing take-up device 10 and the component configuration integrated therewith will be described, then the lock structure and the like will be described, and then the configuration of the pretensioner 100 that is the main part of this embodiment will be described. To do.

[Spool 12 and component configuration integrated therewith]
FIG. 1 is a longitudinal sectional view showing the overall configuration of a webbing take-up device 10 according to this embodiment. As shown in this figure, the webbing retractor 10 includes a frame 14 formed in a substantially U shape in plan view, and the frame 14 is fixed to the vehicle body side. The frame 14 includes a first leg plate 16 and a second leg plate 18 extending in parallel with each other, and a spool 12 manufactured by die casting between the first leg plate 16 and the second leg plate 18 is rotatable. It is supported.

  The spool 12 is formed in a cylindrical shape to form a shaft core portion, and is configured to have a spool shaft 12A in which one end portion of an occupant restraining webbing 126 (see FIG. 10) is locked, and substantially at both ends of the spool shaft 12A. A pair of flange portions each formed in a disc shape (hereinafter, the flange portion disposed on the first leg plate 16 side is referred to as “first flange portion 12B”, and the flange portion disposed on the second leg plate 18 side is referred to as “ The second flange portion 12 </ b> C ”) is formed in a drum shape as a whole.

  A shaft insertion hole 20 is formed in the shaft core portion of the spool shaft 12A. On the side of the first flange portion 12B in the shaft insertion hole 20, a concave base lock receiving portion 22 having a diameter larger than that of the shaft insertion hole 20 is formed coaxially. The base lock receiving portion 22 includes a concave body 22A that occupies most of the base lock, and a concave terminal portion 22B having a larger diameter than the concave body 22A.

  A base lock 24 manufactured by die casting is attached to the base lock receiving portion 22 in a state where it is prevented from coming off. The base lock 24 is attached by inserting a stopper (a retaining member) (not shown) formed in a U shape in front view from the direction perpendicular to the axis after the base lock 24 is inserted into the base lock receiving portion 22. The method is taken. In this embodiment, the base lock 24 is manufactured by die casting. However, it is not always necessary to use die casting, and can be engaged with the ratchet teeth 38A by plastic deformation when pressed against the ratchet teeth 38A when the vehicle suddenly decelerates. What is necessary is just to be comprised with a different material.

  The base lock 24 is formed in a cylindrical shape with a hook, and has a base portion 24A fitted into the concave body 22A of the base lock receiving portion 22, a diameter larger than the base portion 24A, and a concave end portion of the base lock receiving portion 22. The intermediate portion 24B is fitted into 22B, and the holding portion 24C has a larger diameter than the intermediate portion 24B and is disposed in contact with the outer surface of the first flange portion 12B. Further, a hexagonal hole-shaped fitting hole 26 is formed in a portion of the base lock 24 excluding the outer end of the shaft core portion. And a small hole 28 having a smaller diameter than that of the small hole 28 is formed.

  On the other hand, a recessed sleeve receiving portion 30 having a diameter larger than that of the shaft insertion hole 20 is formed on the second flange portion 12C side of the shaft insertion hole 20 of the spool shaft 12A. A sleeve 34 is serrated or spline fitted to the sleeve receiving portion 30. The sleeve 34 is formed in a substantially cylindrical shape and has a base portion 34A in which a hexagonal hole-shaped fitting hole 32 is formed in the shaft core portion, and is formed adjacent to the base portion 34A and is subjected to a flat knurling process on the outer peripheral surface. The intermediate portion 34B and the small diameter portion 34C protruding from the shaft core portion of the intermediate portion 34B. An inner end of an urging means (spring spring) that urges the spool 12 to rotate in the webbing take-up rotation direction is locked to the small diameter portion 34C of the sleeve 34 via an adapter (not shown).

  The base lock 24 and the sleeve 34 described above are connected to each other by a torsion shaft 36. As shown in FIG. 4, the torsion shaft 36 includes a shaft portion 36A constituting a main portion thereof, a hexagonal head portion 36B formed at one end portion of the shaft portion 36A, and the other end portion of the shaft portion 36A. A hexagonal fitting portion 36C formed on the shaft portion 36, a small-diameter portion 36D extending coaxially with the shaft portion 36A from the shaft core portion of the fitting portion 36C, and a diameter reduced from the small-diameter portion 36D through a tapered surface. A gear holding portion 36E that is later enlarged in an annular shape and a tip portion 36F that is further coaxially extended from the gear holding portion 36E and has a key formed thereon. Returning to FIG. 1, the head portion 36 </ b> B of the torsion shaft 36 is fitted into the hexagonal hole-shaped fitting hole 32 formed in the sleeve 34, and the fitting portion 36 </ b> C of the torsion shaft 36 is formed in the base lock 24. It is fitted to the fitting hole 26 having a hexagonal hole shape. Thereby, the torsion shaft 36 is integrated with the spool shaft 12 </ b> A via the base lock 24 and the sleeve 34. The torsion shaft 36 having the above configuration is a main component of a force limiter that absorbs energy by twisting deformation when a webbing tension of a predetermined value or more acts on the spool 12 during sudden deceleration of the vehicle.

  In the above configuration, the spool 12, the base lock 24, the sleeve 34, and the torsion shaft 36 correspond to the “winding shaft” in the present invention.

[Lock structure, etc.]
As shown in FIGS. 2 and 3, an internal ratchet 38 is formed by punching on the upper side of the first leg plate 16 of the frame 14 described above. The ratchet teeth 38A of the internal tooth ratchet 38 are set to have high strength.

  A holding portion 24 </ b> C of the base lock 24 is disposed inside the internal tooth ratchet 38. A small diameter portion 36D of the torsion shaft 36 is inserted into the small hole 28 described above formed in the shaft core portion of the holding portion 24C. On the front side of the holding portion 24C, a concave accommodating portion 40 (see FIGS. 2, 3, and 5) formed in the circumferential direction around the small hole 28 is formed. One end of the accommodating portion 40 is closed, but the other end of the accommodating portion 40 is open. Note that the other end portion side of the accommodating portion 40 of the holding portion 24C in the base lock 24 is chamfered so as not to inhibit the engagement operation of the lock plate 42 to the inner tooth ratchet 38 described below. A single lock plate 42 (see FIGS. 2, 3, and 6) having a substantially arc plate shape is accommodated in the accommodating portion 40. Further, a thin disc-shaped lock cover 44 is attached to the outer surface of the holding portion 24C of the base lock 24 so as to prevent the lock plate 42 from falling off.

  As shown in FIG. 6 and the like, the lock plate 42 includes a metal plate main body 42A having a substantially arc plate shape, a rectangular projection 42B protruding from one end of the plate main body 42A, and a plate main body. 42A, a high-strength locking tooth 42C formed on the outer peripheral portion of the other end portion of the first leg plate 16 and meshing with the ratchet teeth 38A of the inner tooth ratchet 38 of the first leg plate 16, and a guide pin standing from the other end portion of the plate body 42A 42D. The length obtained by adding the width of the plate main body 42A and the protruding length of the protrusion 42B is approximately the same as the width of the wide portion 40A (see FIGS. 2 and 3) of the accommodating portion 40 of the base lock 24.

  At a position adjacent to the base lock 24 described above, a substantially disk-shaped V gear 46 having a larger diameter than this is disposed. As shown in FIG. 7, a cylindrical boss 48 is formed on the shaft core portion of the V gear 46, and is rotatably supported by the gear holding portion 36 </ b> E of the torsion shaft 36. The V gear 46 is formed with a “H” -shaped guide hole 50, and a guide pin 42 D erected from the lock plate 42 is inserted into the guide hole 50. Further, lock teeth 46 </ b> A are integrally formed on the outer peripheral portion of the V gear 46.

  A known acceleration sensor 52 for VSIR shown in FIG. 8 is disposed below the V gear 46. In FIG. 1, the acceleration sensor 52 is not shown. When the vehicle suddenly decelerates, the ball 54 of the acceleration sensor 52 rolls on the sensor housing 56 to swing the sensor lever 58, and the lock claw 58A of the sensor lever 58 is engaged with the lock teeth 46A of the V gear 46. It is like that.

  Returning to FIG. 1, the acceleration sensor 52 described above is held by a resin sensor holder 60. A sensor cover 62 made of resin having a shape similar to that of the sensor holder 60 is disposed outside the sensor holder 60, and the sensor holder 60 and the sensor cover 62 are integrally fixed to the first leg plate 16 of the frame 14. Has been. Further, a short cylindrical boss 60A is integrally formed on the shaft core portion of the sensor holder 60, and a tip end portion 36F of the torsion shaft 36 is pivotally supported by the boss 60A. That is, the sensor holder 60 has a function as a bearing for the torsion shaft 36.

  An inner tooth that can be engaged with a WSIR pawl (not shown) that is pivotally supported by the V gear 46 described above is integrally formed on the inner peripheral portion of the sensor holder 60 described above.

[Configuration of Pretensioner 100]
As shown in FIGS. 9 to 11, the pretensioner 100 is integrated with the second leg plate 18 side of the webbing take-up device 10 described above.

More specifically, the intermediate portion 34B and the small diameter portion 34C of the sleeve 34 mounted on the second leg plate 18 side of the spool 12 are disposed so as to protrude to the outside of the second leg plate 18. A pinion 102 is fitted on the outer peripheral side of the intermediate portion 34B and the small diameter portion 34C. The pinion 102 covers a small-diameter portion 34C of the sleeve 34 and has a tooth portion 104 in which pinion teeth 104A are formed on the outer peripheral portion, and a clutch portion that covers the intermediate portion 34B of the sleeve 34 and is integrally formed adjacent to the tooth portion 104. 106. As shown in FIG. 9, the clutch portion 106 includes a first portion (without reference numerals) perpendicular to the central axis of the spool 12 and a first portion that is integrated with the first portion and is parallel to the central axis of the spool 12. It has 2 parts (no quotes).

  As shown in FIG. 12, three recesses 108 are formed at intervals of 120 degrees on the inner peripheral side of the clutch portion 106. These recesses 108 communicate with each other in the circumferential direction, and rollers 110 are accommodated in the wide portions of the respective recesses 108. As shown in FIG. 13, the outer peripheral surface of the roller 110 is subjected to a flat knurling process having the same configuration as that of the intermediate portion 34 </ b> B of the sleeve 34. The recesses 108 and the rollers 110 correspond to the “clutch” of the present invention.

  In the vicinity of the pinion teeth 104A of the pinion 102 described above, a piston 116 that is accommodated in the cylinder 114 of the cartridge 112 (see FIG. 11) so as to be movable in the axial direction and is configured as a rack bar is disposed. The piston 116 includes a disk-shaped piston portion 118 that receives gas pressure, and a rack portion 120 that is erected from the piston portion 118. A piston ring 122 is attached below the piston portion 118. Further, rack teeth 120 </ b> A that mesh with the pinion teeth 104 </ b> A are formed on one surface of the rack portion 120. Furthermore, the rack part 120 is erected at a position offset from the center of the piston part 118 and is arranged so as to be movable in the axial direction within a range not exceeding the outer diameter of the clutch part 106.

  Note that a gas generator 124 (see FIG. 11) in which a gas generating agent (not shown) is accommodated is connected to the lower end of the cylinder 114 that accommodates the piston 116 described above.

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

  The occupant holds a tongue plate (not shown) inserted through the webbing 126, pulls out the webbing 126 from the spool 12 against the urging force of the mainspring spring, and engages the tongue plate with a buckle device (not shown). The webbing is attached to the seat belt device. That is, the webbing 126 from the shoulder anchor to the tongue plate (not shown) provided on the upper portion of the center pillar becomes the shoulder side webbing, and the webbing 126 from the tongue plate to the buckle device becomes the lap side webbing.

  When the vehicle travels from this state, the pretensioner 100 operates when the vehicle suddenly decelerates. That is, the ignition device is activated, and the gas generating agent accommodated in the gas generator 124 of the cartridge 112 burns to generate gas. The generated gas is supplied from the gas generator 124 to the lower end portion of the cylinder 114. For this reason, the piston 116 accommodated in the cylinder 114 moves in the axial direction. When the piston 116 moves in the axial direction, the rack teeth 120A of the rack portion 120 of the piston 116 mesh with the pinion teeth 104A of the tooth portion 104 of the pinion 102, and rotate this in the webbing take-up rotation direction. For this reason, the clutch part 106 integrated with the tooth part 104 of the pinion 102 is also rotated in the same direction.

  As a result, the roller 110 held in the concave portion 108 of the clutch portion 106 relatively moves from the wide portion to the narrow portion, and is sandwiched between the back side surface of the concave portion 108 and the outer peripheral surface of the intermediate portion 34B of the sleeve 34. It is. Since the outer peripheral surface of the intermediate portion 34B of the sleeve 34 and the outer peripheral surface of the roller 110 are both subjected to flat knurling, they are in meshing state. As a result, the pinion 102 and the sleeve 34 are connected via the clutch portion 106, and the rotational force of the pinion 102 is directly transmitted to the sleeve 34.

  Since the base portion 34A of the sleeve 34 and the spool shaft 12A of the spool 12 are serrated or spline-fitted, when the sleeve 34 rotates in the webbing take-up rotation direction, the spool 12 also rotates in the webbing take-up rotation direction. . As a result, the webbing 126 is wound up by an amount corresponding to the movement stroke of the piston 116 to tightly restrain the occupant.

  At the same time, the vehicle sudden deceleration state is detected by the acceleration sensor 52. That is, the ball 54 of the acceleration sensor 52 rolls on the sensor housing 56 to swing the sensor lever 58. Thereby, the lock claw 58A of the sensor lever 58 is engaged with the lock teeth 46A of the V gear 46, and the rotation of the V gear 46 in the webbing pull-out direction is prevented.

On the other hand, the spool 12 tries to rotate in the webbing pull-out direction by the webbing tension received from the passenger. For this reason, relative rotation occurs between the spool 12 that is about to rotate in the webbing pull-out direction and the V gear 46 that is prevented from rotating in the webbing pull-out direction. When relative rotation occurs between the two, the guide pin 42D of the lock plate 42 held in the receiving portion 40 formed in the holding portion 24C of the base lock 24 becomes V gear as can be seen from the comparison between FIG. 2 and FIG. It is guided by the guide holes 50 of 46 and moved to the outer side of the base lock 24 in the substantially radial direction. Thereby, the lock teeth 42 </ b> C of the lock plate 42 mesh with the ratchet teeth 38 </ b> A of the internal tooth ratchet 38 provided on the first leg plate 16 of the frame 14.

  Further, when the lock teeth 42 </ b> C of the lock plate 42 mesh with the ratchet teeth 38 </ b> A of the internal tooth ratchet 38, the reaction force at that time acts on the holding portion 24 </ b> C of the base lock 24. This reaction force is generated by the engagement of the high-strength lock teeth 42C and the ratchet teeth 38A during sudden deceleration of the vehicle, and is therefore quite large. Therefore, it naturally acts on the torsion shaft 36 that penetrates the shaft core portion of the base lock 24. . Further, since the front end portion 36F of the torsion shaft 36 is pivotally supported by the boss 60A of the resin sensor holder 60, the reaction force acts on the boss 60A of the sensor holder 60 from the front end portion 36F of the torsion shaft 36. The boss 60 </ b> A of the holder 60 is elastically deformed in the direction of reaction force, that is, in the direction opposite to the engagement position of the lock plate 42. For this reason, a part of the outer periphery of the holding portion 24 </ b> C of the base lock 24 (range centered on the portion indicated by the arrow P in FIG. 3) is strongly pressed against the ratchet teeth 38 </ b> A of the internal tooth ratchet 38 of the frame 14. Since the base lock 24 is manufactured by die casting and is relatively soft, when it is pressed against the ratchet teeth 38A, it is plastically deformed and bites into the ratchet teeth 38A and is directly engaged. As a result, rotation of the spool 12 in the webbing pull-out direction is prevented and the spool 12 is locked.

  The basic operation of the webbing take-up device 10 and the pretensioner 100 according to the present embodiment has been described above. As can be seen from the description of the operation, in the present embodiment, a pre-drive employing a rack and pinion type drive mechanism is employed. In the tensioner 100, the pinion 102 that rotates by receiving the driving force of the piston 116 configured as a rack bar is directly connected to the shaft end of the sleeve 34 via the clutch portion 106, so that an intermediate gear as in the prior art is not required. Become. For this reason, it is not necessary to provide the pretensioner 100 with an installation space for these intermediate gears. Therefore, the pretensioner 100 can be reduced in size in the axial direction and the radial direction as a whole.

  In particular, in the present embodiment, since the tooth portion 104 and the clutch portion 106 are integrated to form the pinion 102, the installation space is larger than when the tooth portion 104 and the clutch portion 106 are set separately and independently. Can be further reduced. Therefore, further downsizing of the entire device of the pretensioner 100 can be achieved. In addition, since the number of parts is reduced, the structure can be simplified.

  Further, in the present embodiment, the piston 116 includes the piston portion 118 and the rack portion 120, the rack portion 120 is erected at a position offset from the center of the piston portion 118, and the clutch portion 106 is Since it is arranged so as to move in the axial direction within a range that does not exceed the outer diameter, it is possible to avoid the rack-and-pinion drive mechanism from expanding in the radial direction. As a result, according to this embodiment, the entire apparatus of the pretensioner 100 can be made very compact.

  Further, in the present embodiment, as described above, the pinion 102 is directly connected to the sleeve 34 that constitutes a part of the take-up shaft. Therefore, from the piston 116 (rack bar) serving as the driving start point to the driving end point (sleeve 34). The driving force transmission path is shortened. For this reason, the response speed of the pretensioner 100 can be increased.

  In the present embodiment, the present invention is applied to the webbing take-up device 10 that has both the pretensioner 100 and the force limiter. However, the present invention is not limited to this, and the present invention is applied to a webbing take-up device that does not include the force limiter. The pretensioner according to the invention may be applied.

  Further, in the present embodiment, the rack portion 120 is configured to move in the axial direction within a range not exceeding the outer diameter dimension of the clutch portion 106 by arranging the rack portion 120 so as to be offset with respect to the center of the piston portion 118. However, the relationship with the present invention described in claim 1 includes a configuration in which the rack portion is coaxially arranged at the center of the piston portion.

  Further, in the present embodiment, the clutch using the roller 110 is used. However, the present invention is not limited to this, and various clutch configurations such as a clutch using a ball instead of the roller 110 can be adopted.

It is a longitudinal section showing the whole webbing winding device composition concerning this embodiment. It is a side view which shows the non-locking state of the webbing winding device concerning this embodiment. It is a side view which shows the locked state of the webbing winding device concerning this embodiment. FIG. 2 is a front view of the torsion shaft shown in FIG. 1. It is a side view of the base lock shown by FIG. FIG. 2 is a front view of the lock plate shown in FIG. 1. It is a rear view of the V gear shown by FIG. It is a side view of the acceleration sensor which abbreviate | omitted illustration in FIG. It is sectional drawing which expands and shows the principal part of the pretensioner integrated with the webbing winding device. It is a perspective view which shows the rack and pinion type drive mechanism of a pretensioner. It is a schematic side view of the webbing take-up device with an integrated pretensioner. It is the reverse view which looked at the pinion shown by FIG. 9 from the arrow Q direction. (A) is a front view of the roller shown in FIG. 9, and (B) is a plan view of the roller.

Explanation of symbols

10 Webbing take-up device 12 Spool (winding shaft)
20 Shaft insertion hole 24 Base lock (winding shaft)
30 Sleeve receiving portion 32 Fitting hole 34 Sleeve (winding shaft)
34A Base portion 34B Intermediate portion 34C Small diameter portion 36 Torsion shaft (winding shaft)
100 Pretensioner 102 Pinion 104 Tooth part 104A Pinion tooth 106 Clutch part 108 Recessed part (clutch)
110 Roller (clutch)
114 Cylinder 116 Piston 118 Piston part 120 Rack part 120A Rack tooth 126 Webbing

Claims (2)

Integrated into a webbing take-up device that takes up a webbing for restraining passengers on a take-up shaft, and a rack-and-pinion-type drive mechanism that instantaneously rotates the take-up shaft by a predetermined amount in the webbing take-up rotation direction when the vehicle suddenly decelerates. A webbing take-up device with a tensioner,
The drive mechanism is disposed in the cylinder so as to be movable in the axial direction, and is disposed so as to mesh with a piston that moves when the vehicle suddenly decelerates, and a rack tooth of the piston. And a pinion directly connected to the winding shaft via
The pinion includes a tooth portion formed with pinion teeth that mesh only with the rack teeth, and a clutch portion that is coaxially and integrally formed with the tooth portion and includes the clutch on the inner peripheral side. Has been
The piston includes a piston portion and a rack portion standing at a position offset from the center of the piston portion.
Furthermore, the webbing retractor with a pretensioner is characterized in that at least the corners of the rack teeth are chamfered so that the outer shape of the rack portion does not protrude from the outer shape of the piston portion when viewed in the axial direction of the piston.   The rack teeth formed on the rack portion of the piston are arranged apart from the pinion teeth formed on the tooth portion of the pinion before the pretensioner is operated, and the piston is axially moved by the operation of the pretensioner. 2. The webbing retractor with a tensioner according to claim 1, wherein the rack teeth mesh with the pinion teeth when moved.

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