JP2009227062A - Seat belt retractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt retractor capable of starting deformation of an energy absorbing member by holding the energy absorbing member without using a complicated locking mechanism after firmly restraining the body of an occupant by winding up a webbing. <P>SOLUTION: Rotating torque does not work on a torsion bar when a rack 48 rotates a winding shaft 20 in the winding direction as the rack 48 rotates the winding shaft in the winding direction by engaging with a winding shaft side gear 40 of the winding shaft on the seat belt retractor. Consequently, torsional deformation never occurs on the torsion bar when the rack 48 rotates the winding shaft 20 in the winding direction. Additionally, any special constitution to revolve a first lock pawl 52 is not basically required as one end of the torsion bar is held by engaging a ratchet part 54 of the pawl 52 with a ratchet part 56 of a lock base 34 as the rack 48 revolves the first lock pawl 52 when engagement of the rack 48 and the winding shaft side gear 40 is finished. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seat belt retractor that winds and stores a webbing for restraining the body of an occupant seated in a vehicle seat.

  In the seat belt retractor with a pretensioner disclosed in Patent Document 1 below, when the pretensioner mechanism is operated, the rack of the pretensioner mechanism is in the winding direction, which is the rotation direction when the winding shaft (bobbin) winds up the webbing. Rotates the pinion. Thus, when the rack rotates the pinion, the clutch rotor is rotated at a higher speed by the speed-up gear transmission, and the clutch mechanism is operated. Thus, the clutch rotor rotates the sleeve in the winding direction, and the retainer equipped with the sleeve rotates the winding shaft and the energy absorbing member (torsion bar) in the winding direction.

Thus, in the retractor for seat belts with a pretensioner disclosed in Patent Document 1, the rotational force of the pinion applied from the rack can be transmitted to the winding shaft without going through the energy absorbing member. Unnecessary torsional deformation does not occur in the energy absorbing member.
Japanese Patent Laid-Open No. 10-71930

  However, in the retractor for a seat belt with a pretensioner disclosed in Patent Document 1, a complicated locking mechanism provided separately from the pretensioner for holding the energy absorbing member for causing torsional deformation of the energy absorbing member. Is required.

  In consideration of the above facts, the present invention starts the deformation of the energy absorbing member by winding the webbing and firmly restraining the occupant's body, and then holding the energy absorbing member without using a complicated locking mechanism. The object is to obtain a seat belt retractor that can be used.

  The seat belt retractor according to the first aspect of the present invention is such that the longitudinal base end portion of the long webbing is locked, and the webbing is rotated by rotating in the winding direction that is one of its own axes. A take-up shaft having a take-up shaft main body portion and having a take-up shaft side gear coaxially formed at one axial end portion of the take-up shaft main body portion, and the other axial end of the take-up shaft main body portion An energy absorbing member having a coupling portion fixed to the take-up shaft between the center portion and the intermediate portion and the take-up shaft-side gear in the take-up direction by being displaced in a state of being engaged with the take-up shaft-side gear. A first rotation forcing member that rotates the first rotation forcing member to displace the first rotation forcing member, and the first rotation forcing member rotates the winding shaft side gear by a predetermined angle, and then the coupling is performed. Directly or between the energy absorbing member at a part different from the part And a, a rotational force means for restricting the rotation of the energy absorbing member to engage.

  In the seat belt retractor according to the first aspect of the present invention, when the rotation forcing means is operated in a state where the webbing is mounted on the body of the vehicle occupant, the first rotation forcing member constituting the rotation forcing means is displaced. Then, the winding shaft side gear meshing with the first rotation forcing member is forcibly rotated in the winding direction. The take-up shaft side gear is formed coaxially with the take-up shaft main body portion where the base end portion of the webbing is locked, so that the take-up shaft side gear rotates in the take-up direction. The part is forcibly rotated in the winding direction. As a result, the webbing is taken up by the take-up shaft main body, and the occupant's body is more strongly restrained by the webbing.

  Further, when the first rotation forcing member forcibly rotates the take-up shaft side gear in the winding direction by a certain angle in this way, the rotation forcing means is directly or indirectly provided at a site different from the coupling portion of the energy absorbing member. Engagement thereby restricts rotation of the energy absorbing member. Since the energy absorbing member is integrally coupled to the take-up shaft at the coupling portion, when the occupant's body pulls the webbing and forcibly rotates the take-up shaft in the pull-out direction opposite to the take-up direction. The energy absorbing member also rotates in the drawing direction.

  However, as the rotation forcing means engages with the energy absorbing member as described above, the rotation of the energy absorbing member in the drawing direction is restricted, and indirectly, the rotation of the winding shaft in the drawing direction is restricted. . For this reason, in this state, the webbing is not pulled out from the winding shaft main body. For this reason, for example, even when the occupant's body is about to move inertially toward the vehicle front side when the vehicle is suddenly decelerated, the occupant's body is firmly held by the webbing in which the pull-out from the take-up shaft is restricted to the vehicle front side. The inertial movement of the occupant's body can be effectively regulated.

  Further, when the webbing pulled by the occupant's body rotates the winding shaft in the pull-out direction with a force exceeding the mechanical strength of the energy absorbing member, the portion of the energy absorbing member engaged with the rotation forcing means, and the winding Relative torsional deformation occurs between the shaft coupling portions. The take-up shaft is allowed to rotate in the pull-out direction by the amount of twist of the energy absorbing member, and the webbing is drawn out from the take-up shaft main body by the rotation allowance of the take-up shaft. Therefore, the occupant's body can move to the front side of the vehicle by the amount of webbing that is allowed in this way, and part of the energy of the pulling force of the webbing by the occupant's body is twisted by the energy absorbing member. Absorbed by deformation.

  Here, in the seat belt retractor according to the present invention, as described above, when the rotation forcing means is operated, the first rotation forcing member is engaged with the winding shaft side gear formed on the winding shaft, and the winding shaft side gear is engaged. Since it rotates in the winding direction, the force of the first rotation forcing member is not used for the deformation of the energy absorbing member. In addition, when the first rotation forcing member rotates the take-up shaft side gear by a certain angle, the rotation forcing means engages the energy absorbing member directly or indirectly to restrict the rotation of the energy absorbing member, so that a special locking mechanism is used. Is basically unnecessary. For this reason, the whole structure can be simplified.

  A seat belt retractor according to a second aspect of the present invention is the seat belt retractor according to the first aspect of the present invention, wherein an energy absorbing member side gear coaxial with the winding shaft main body portion is different from the coupling portion. The energy absorbing member is integrally provided at the site, and after the first rotation forcing member starts to be displaced, meshes with the energy absorbing member side gear, forcing the energy absorbing member side gear in the winding direction. The said rotation forcing means is comprised including the 2nd rotation forcing member to rotate.

  In the seat belt retractor according to the second aspect of the present invention, after the first rotation forcing member of the rotation forcing means forcibly rotates the winding shaft side gear in the winding direction, the second rotation of the rotation forcing means is performed. The forcing member rotates the energy absorbing member side gear provided on the energy absorbing member in the winding direction.

  As described above, in the seat belt retractor according to the present invention, the second rotation forcing member rotates the energy absorbing member. However, when the second rotation forcing member rotates the energy absorbing member, the first rotation forcing member is already used. Rotates the take-up shaft side gear in the take-up direction, so that a large rotational force required to rotate the energy absorbing member-side gear in the take-up direction with the energy absorbing member-side gear stopped is on the energy absorbing member side. Even if it is not applied to the gear, the energy absorbing member side gear can be rotated in the winding direction by the rotational force of the second rotation forcing member.

  As described above, the seat belt retractor according to the first aspect of the present invention has a configuration in which the webbing is taken up by the take-up shaft and the occupant's body is firmly restrained, and then the energy of the seat belt retractor is reduced without using a complicated lock mechanism. The absorbing member can be held to start the deformation of the energy absorbing member.

  The seat belt retractor according to the second aspect of the present invention provides the energy absorbing member side gear with a large rotational force required to rotate the energy absorbing member side gear in the winding direction with the energy absorbing member side gear stopped. Even if not provided, the energy absorbing member side gear can be rotated in the winding direction by the rotational force of the second rotation forcing member.

<Configuration of First Embodiment>
FIG. 1 is a front sectional view schematically showing the overall configuration of a seat belt retractor 10 according to a first embodiment of the present invention.

  As shown in FIG. 1, the seat belt retractor 10 includes a main body 12. The main body 12 includes a flat plate-like main body base 14, and the main body base 14 is fixed to the vehicle body by fastening means (not shown) such as a bolt, for example, near the lower end of the center pillar of the vehicle. The retractor 10 is attached to the vehicle body.

  A pair of side walls 16 and 18 facing each other substantially in the vehicle front-rear direction extend in parallel with each other from the main body base portion 14. A winding shaft 20 is disposed between the side walls 16 and 18. The take-up shaft 20 includes a cylindrical take-up shaft main body 22 whose axial direction is the opposite direction of the side walls 16 and 18.

  A longitudinal base end portion of a long belt-like webbing 24 is engaged with the take-up shaft main body 22. The take-up shaft 20 is rotatable around the central axis of the take-up shaft main body portion 22, and the webbing 24 rotates in the take-up direction that is one of the axes around the axis so that the webbing 24 is in the longitudinal base end side. Are wound and stored in layers on the outer periphery of the take-up shaft main body 22. Further, when the webbing 24 is pulled from the front end side, the webbing 24 taken up by the take-up shaft main body 22 is drawn out, and accordingly, the take-up shaft 20 rotates in a pull-out direction opposite to the take-up direction.

  On the other hand, the seat belt retractor 10 includes a torsion bar 26 as an energy absorbing member. The torsion bar 26 includes a coupling portion 28 provided inside the take-up shaft 20 at an intermediate portion in the axial direction of the take-up shaft 20. The outer peripheral shape of the coupling portion 28 is non-circular, and engages with the inner peripheral wall of the winding shaft 20 in a state in which relative rotation with respect to the winding shaft 20 around the central axis of the winding shaft 20 is impossible. A first variable portion 30 is formed on the side wall 16 side of the coupling portion 28. The first variable portion 30 has a rod shape in which the axial direction is substantially the same as the axial direction of the winding shaft 20, and one end thereof is integrally connected to the coupling portion 28. A coupling portion 32 having a non-circular outer shape is formed at the other end of the first variable portion 30.

  A lock base 34 is provided on the side of the side wall 16 of the winding shaft 20 corresponding to the coupling portion 32. The lock base 34 is fitted in a fitting insertion hole 36 opened at the end surface of the winding shaft 20 on the side wall 16 side. The fitting insertion hole 36 has a circular inner shape that is coaxial with the central axis of the winding shaft 20, and the lock base 34 fitted into the fitting insertion hole 36 is coaxial with the winding shaft 20. Relative rotation is possible.

  The lock base 34 is formed with an insertion hole 38 whose inner peripheral shape corresponds to the outer peripheral shape of the coupling portion 32. The coupling portion 32 is fitted in the insertion hole 38. As described above, the lock base 34 is fitted in the insertion hole 36 so as to be coaxially rotatable with respect to the winding shaft 20, but the lock base 34 is not relatively rotatable with respect to the coupling portion 32. The winding shaft 20 cannot rotate relative to the coupling portion 28. For this reason, the lock base 34 is connected to the winding shaft 20 through the torsion bar 26 so as not to be relatively rotatable.

  A take-up shaft side gear 40 is formed on the side wall 16 side of the take-up shaft 20 in which the fitting insertion hole 36 is formed, that is, on the end portion on the side wall 16 side of the take-up shaft main body 22. As shown in FIG. 3, the take-up shaft side gear 40 is an externally toothed pinion gear that is coaxial with the central axis of the take-up shaft 20, and passes through a hole formed in the side wall 16. Projects outward. Corresponding to the take-up shaft side gear 40, a pretensioner 42 constituting a rotation forcing means is provided outside the side wall 16.

  The pretensioner 42 includes a cylinder 44 whose axial direction is orthogonal to the axial direction of the winding shaft 20. A piston (not shown) is slidably accommodated inside the cylinder 44. The base end portion of the bar 46 is connected to the piston. The front end side of the bar 46 is out of the cylinder 44 and passes through the side of the outer peripheral portion of the winding shaft side gear 40. Further, a rack 48 as a first rotation forcing member is formed at the tip of the bar 46. The rack 48 is formed with teeth that can mesh with the external teeth of the take-up shaft side gear 40. In the initial state, the rack 48 is not engaged with the take-up shaft side gear 40, and when the bar 46 is pulled inside the cylinder 44, the rack 48 is engaged with the take-up shaft side gear 40 and winds the take-up shaft side gear 40. It is designed to rotate in the taking direction.

  The cylinder 44 is provided with gas generating means such as a microgenerator (not shown). The gas generating means operates to supply gas to the distal end side of the cylinder 44 and slide the piston in the cylinder 44 toward the proximal end side of the cylinder 44 with the gas pressure. Thereby, the bar 46 is drawn into the cylinder 44 from the base end side.

  On the other hand, as shown in FIG. 1, a shaft 50 is provided on the side of the winding shaft 20 on the outer side in the rotational radius direction of the winding shaft 20. The shaft 50 has an axial direction that is the same as the axial direction of the winding shaft 20, and one end of the shaft 50 is rotatably supported on the side wall 16 and the other end is rotatably supported on the side wall 18. A first lock pawl 52 constituting a rotation forcing means together with the pretensioner 42 is provided on one end side of the shaft 50.

  The first lock pawl 52 is disposed outside the side wall 16 and is integrally connected to one end of the shaft 50. As shown in FIG. 3, the first lock pawl 52 includes a ratchet portion 54. The ratchet portion 54 is formed with external ratchet teeth. When the first lock pawl 52 rotates to one side around the shaft 50, the ratchet teeth of the ratchet portion 54 come out of the winding shaft side gear 40. The outer periphery of the lock base 34 is approached. A ratchet portion 56 is formed on the outer peripheral portion of the lock base 34 protruding outside the winding shaft side gear 40.

  The ratchet portion 56 is an external ratchet tooth that can mesh with the ratchet portion 54. As described above, when the first lock pawl 52 rotates and the ratchet portion 54 approaches the outer peripheral portion of the lock base 34, the ratchet portion 54 meshes with the ratchet portion 56. When the ratchet portion 54 is engaged with the ratchet portion 56, the rotation of the lock base 34 in the pull-out direction is restricted.

  Further, the first lock pawl 52 is formed with an engaging portion 58. The engaging portion 58 is formed on the extension of the teeth of the rack 48 along the sliding direction of the bar 46. For this reason, the bar 46 is drawn into the cylinder 44 and slides so that the rack 48 meshes with the take-up shaft side gear 40, and the teeth of the rack 48 that have finished meshing with the take-up shaft side gear 40 are engaged with the engaging portion. 58 abuts. When the rack 48 in contact with the engaging portion 58 further presses the engaging portion 58, the first lock pawl 52 is rotated in a direction in which the ratchet portion 54 approaches the ratchet portion 56.

  On the other hand, as shown in FIG. 1, a support portion 66 having a noncircular outer peripheral shape is provided on the side wall 18 side of the shaft 50. The support portion 66 is provided integrally with the shaft 50 outside the side wall 18. A second lock pawl 72 is provided outside the side wall 18. As shown in FIG. 7, the second lock pawl 72 has a through hole having substantially the same shape as the outer periphery of the support portion 66, and the support portion 66 passes through the through hole. A lock pawl 72 is supported by the support portion 66. As described above, since the outer peripheral shape of the support portion 66 and the inner peripheral shape of the through hole of the second lock pawl 72 are non-circular, the relative rotation of the second lock pawl 72 with respect to the support portion 66 is impossible. The second lock pawl 72 can slide with respect to the support portion 66 along the axial direction of 50.

  A lock base 74 is provided on the side of the second lock pawl 72. A fitting insertion hole 76 is formed in the winding shaft main body 22 corresponding to the lock base 74. The lock base 74 is opened at an end surface of the winding shaft main body 22 on the side wall 18 side, and a fitting insertion hole 76 is fitted therein. The inner circumferential shape of the fitting insertion hole 76 is a circle that is coaxial with the central axis of the winding shaft 20, and opens at the end surface of the winding shaft main body 22 on the side wall 18 side. For this reason, the fitting insertion hole 76 fitted into the lock base 74 is rotatable relative to the winding shaft main body 22. A ratchet portion 78 is formed on the outer peripheral portion of the lock base 74 that protrudes outside the fitting insertion hole 76.

  The ratchet portion 78 is an external ratchet tooth that is coaxial with the winding shaft 20. A ratchet portion 80 is formed on the second lock pawl 72 corresponding to the ratchet portion 78. The ratchet portion 80 is an external ratchet tooth that can mesh with the ratchet portion 78. When the shaft 50 rotates until the ratchet portion 54 of the first lock pawl 52 engages with the ratchet portion 56 of the lock base 34, the ratchet portion 80 is It is set to mesh with the ratchet portion 78. Thus, in the state where the ratchet portion 80 is engaged with the ratchet portion 78, the rotation of the lock base 74 in the pull-out direction is restricted.

  As shown in FIG. 1, a squib 82 is provided on the side of the ratchet portion 80 (second lock pawl 72). The squib 82 is an embodiment of a gas generating means that generates gas when operated, and causes the plunger 84 to protrude with the pressure of the gas generated by operating. The squib 82 is controlled by a control means such as an ECU for controlling the gas generation means of the pretensioner 42. The pretensioner 42 is operated, and the physique of the occupant seated on the seat corresponding to the seat belt retractor 10 is also provided. The squib 82 is activated when the control means determines that the occupant's physique is small based on a signal from a physique detection sensor (not shown) that detects the sway.

  The plunger 84 that protrudes when the squib 82 is operated presses the second lock pawl 72 in the axial direction of the shaft 50. Thus, the second lock pawl 72 pressed by the plunger 84 slides while being guided by the support portion 66. In this state, even if the shaft 50 rotates, the ratchet portion 80 is displaced from the ratchet portion 78 along the axial direction of the shaft 50, so that the ratchet portion 80 cannot be engaged with the ratchet portion 78.

  On the other hand, a second variable portion 86 is formed on the side wall 18 side of the coupling portion 28. The second variable portion 86 has a rod shape whose axial direction is substantially the same as the axial direction of the winding shaft 20, and one end of the second variable portion 86 is integrally connected to the coupling portion 28. At the other end of the second variable portion 86, a coupling portion 88 whose outer peripheral shape is non-circular is formed.

  Corresponding to the coupling portion 88, the lock base 74 is formed with a fitting insertion hole 90 whose inner circumferential shape corresponds to the outer circumferential shape of the coupling portion 88. The coupling portion 88 is fitted in the insertion hole 90. As described above, the lock base 74 is fitted into the insertion hole 36 so as to be coaxially rotatable with respect to the winding shaft 20, but the lock base 74 is not relatively rotatable with respect to the coupling portion 88. The winding shaft 20 cannot rotate relative to the coupling portion 28. For this reason, the lock base 74 is connected to the winding shaft 20 through the torsion bar 26 so as not to be relatively rotatable.

<Operation and Effect of First Embodiment>
Next, the operation and effect of the present embodiment will be described.

  In the seat belt retractor 10, when an acceleration sensor (not shown) detects a sudden deceleration state of the vehicle, a control unit such as an ECU activates the gas generation unit of the pretensioner 42. When gas is generated from the gas generating means of the pretensioner 42, the piston in the cylinder 44 slides due to this gas pressure, and the bar 46 is drawn into the cylinder 44. When the bar 46 slides in this way, the rack 48 meshes with the take-up shaft side gear 40 and rotates the take-up shaft side gear 40 in the take-up direction, as shown in FIG. As a result, when the take-up shaft main body 22 rotates in the take-up direction, the webbing 24 is taken up by the take-up shaft main body 22 from the longitudinal base end side. Thus, the body of the passenger wearing the webbing 24 is firmly restrained by the webbing 24 by winding the webbing 24.

  Next, when the bar 46 is further pulled into the cylinder 44 in this state, the teeth located closest to the cylinder 44 in the rack 48 come into contact with the engaging portion 58 as shown in FIG. When the bar 46 is further pulled into the cylinder 44 in this state, the rack 48 presses the engaging portion 58 to rotate the first lock pawl 52 around the shaft 50. Thereby, as shown in FIG. 6, the ratchet portion 54 of the first lock pawl 52 meshes with the ratchet portion 56, and the rotation of the lock base 34 in the pull-out direction is restricted.

  On the other hand, as described above, when the shaft 50 is rotated until the ratchet portion 54 is engaged with the ratchet portion 56, the ratchet portion 78 of the second lock pawl 72 is moved as shown by an imaginary line (two-dot chain line) in FIG. It rotates to a position where it can engage with the ratchet portion 80 of the lock base 74. Here, based on the detection result of the physique detection sensor, if the control means such as the ECU determines that the occupant seated on the seat is not small, the ratchet portion 78 of the second lock pawl 72 is locked base. It meshes with 74 ratchet portions 80.

  On the other hand, if the control means such as the ECU determines that the occupant seated on the seat is small, the squib 82 is activated when the gas generating means of the pretensioner 42 is activated, and the plunger 84 is The second lock pawl 72 is pressed, and the second lock pawl 72 is slid along the support portion 66 as shown in FIG. Therefore, in this state, although the second lock pawl 72 rotates, the ratchet portion 78 is displaced in the axial direction of the shaft 50 with respect to the ratchet portion 80, so that the ratchet portion 78 of the second lock pawl 72 has the lock base 74. The ratchet portion 80 cannot be engaged.

  As described above, when the ratchet portion 54 of the first lock pawl 52 is engaged with the ratchet portion 56 of the lock base 34, the winding shaft 20 cannot rotate in the pull-out direction. Therefore, for example, even if the occupant's body pulls the webbing 24 due to inertial movement of the occupant's body due to sudden deceleration of the vehicle, the webbing 24 cannot be pulled out from the take-up shaft main body 22. For this reason, the occupant's body is firmly held by the webbing 24, and the inertial movement of the occupant's body toward the front side of the vehicle is effectively restricted.

  Further, in this state, when the occupant's body pulls the webbing 24, the rotational force in the pull-out direction applied to the winding shaft main body portion 22 is transmitted from the winding shaft 20 to the coupling portion 28. In the state where the occupant's body is small and the second lock pawl 72 pressed by the plunger 84 slides, if the rotational force transmitted in the pulling direction transmitted to the coupling portion 28 exceeds the mechanical strength of the first variable portion 30, Torsional deformation occurs in the first variable portion 30 such that the coupling portion 28 rotates in the pull-out direction with respect to the coupling portion 32.

  The take-up shaft 20 can rotate in the pull-out direction by the torsional deformation of the first variable portion 30, and the webbing 24 is pulled out from the take-up shaft main body portion 22 by the allowable rotation in the pull-out direction of the take-up shaft 20. Therefore, the occupant can move to the front side of the vehicle by the amount of the webbing 24 pulled out from the take-up shaft main body 22, and part of the energy of the force with which the occupant's body pulls the webbing 24 is Absorbed by torsional deformation.

  On the other hand, when the occupant's body is not small, rotation of the lock base 74 in the pull-out direction is also restricted. For this reason, in this case, when the rotational force in the pull-out direction exceeding the sum of the mechanical strength of the first variable portion 30 and the mechanical strength of the second variable portion 86 is transmitted to the coupling portion 28, the coupling is performed as described above. The first variable portion 30 undergoes torsional deformation so that the coupling portion 28 rotates in the pull-out direction with respect to the portion 32, and the second so that the coupling portion 28 rotates in the pull-out direction with respect to the coupling portion 88. Torsional deformation occurs at the variable portion 86.

  The take-up shaft 20 can rotate in the pull-out direction by the amount of torsional deformation of the first variable portion 30 and the second variable portion 86, and the webbing from the take-up shaft main body portion 22 by the allowable rotation in the pull-out direction of the take-up shaft 20 24 is pulled out. For this reason, the occupant can move to the front side of the vehicle by the amount that the webbing 24 is pulled out from the take-up shaft main body 22, and part of the energy of the force with which the occupant's body pulls the webbing 24 is It is absorbed by the torsional deformation of the second variable portion 86.

  In this way, in the seat belt retractor 10, the rack 48 meshes with the take-up shaft side gear 40 of the take-up shaft 20 and rotates the take-up shaft 20 in the take-up direction, so that the rack 48 winds the take-up shaft 20. No rotational torque acts on the coupling portion 28 when rotating in the take-off direction. For this reason, the torsion bar 26 is not twisted and deformed when the rack 48 rotates the winding shaft 20 in the winding direction.

  Further, as described above, when the engagement between the rack 48 and the take-up shaft side gear 40 is finished, the rack 48 presses the first lock pawl 52 to rotate the first lock pawl 52, and the ratchet portion 54 is ratchet. Since it meshes with the portion 56, a special configuration for rotating the first lock pawl 52 is basically unnecessary, so that the entire apparatus of the seat belt retractor 10 can be simplified. In addition, since the second lock pawl 72 can be rotated only by connecting the first lock pawl 52 and the second lock pawl 72 with the shaft 50, a configuration for rotating the second lock pawl 72 is also provided. This is simple and does not cause a delay in the torsional deformation start timing of the second variable portion 86 with respect to the torsional deformation start timing of the first variable portion 30.

<Configuration of Second Embodiment>
Next, a second embodiment of the present invention will be described. In the description of the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  FIG. 8 is a front sectional view schematically showing the overall configuration of the seat belt retractor 110 according to the present embodiment.

  As shown in FIG. 8, in the seat belt retractor 110, the fitting insertion hole 76 is not formed on the 018 side of the winding shaft 20, and a fitting insertion hole 112 is formed instead. Unlike the fitting hole 76, the fitting hole 112 has a noncircular inner shape. An adapter 114 is inserted into the insertion hole 112. Since the outer peripheral shape of the portion inserted into the insertion hole 112 of the adapter 114 is the same non-circular shape as the inner peripheral shape of the insertion hole 112, the winding shaft is inserted in the state where the adapter 114 is inserted into the insertion hole 112. The relative rotation of the adapter 114 with respect to 20 becomes impossible.

  Further, the seat belt retractor 110 does not include the torsion bar 26 but includes a torsion bar 116 as an energy absorbing member instead. The torsion bar 116 includes a coupling portion 118. The joint portion 118 has a non-circular outer shape similar to the joint portion 28 of the torsion bar 26. The adapter 114 has a fitting insertion hole 120 corresponding to the coupling portion 118. The inner shape of the insertion hole 120 is a non-circular shape that is the same as the outer shape of the coupling portion 118, and the coupling portion 118 is inserted into the insertion hole 120. For this reason, the torsion bar 116 is basically incapable of relative rotation with respect to the winding shaft 20. A rod-shaped variable portion 122 is integrally connected to the surface of the coupling portion 118 on the side wall 16 side. A coupling portion 32 is formed at the end of the fitting insertion hole 112 on the side wall 18 side.

  Further, the seat belt retractor 110 does not include the lock base 34 but includes a lock base 124 instead. The lock base 124 is inserted into an insertion hole 36 formed in the winding shaft 20 and is basically the same as the lock base 34 in that it can rotate relative to the winding shaft 20. However, the ratchet portion 56 is not formed on the lock base 124, and instead, a lock base gear 126 as an energy absorbing member side gear is formed. As shown in FIG. 9, the lock base gear 126 is an external pinion gear that is coaxial with the winding shaft 20.

  On the other hand, the seat belt retractor 110 does not include the pretensioner 42 but includes a pretensioner 132 as a rotation forcing unit instead. The pretensioner 132 includes a cylinder 134. In the cylinder 134, a piston having a base end portion of the bar 136 fixedly connected is slidably accommodated. However, the pretensioner 132 is different from the pretensioner 42 in the first embodiment when the gas generating means such as the micro gas generator is operated, the bar 136 that has been previously drawn into the cylinder 134 is moved to the outside of the cylinder 134. The piston slides with gas pressure so as to push it out.

  A rack bar 138 is integrally connected to the tip of the bar 136. The rack bar 138 includes a bar-shaped rack base 140 that is continuous from the tip of the bar 136. A first rack 142 as a first rotation forcing member is formed corresponding to the take-up shaft side gear 40 on the side wall 16 side of the intermediate portion of the rack base portion 140 along the axial direction of the take-up shaft 20. . A second rack 144 serving as a second rotation forcing member is disposed on the side opposite to the side wall 16 from the intermediate portion of the rack base 140 along the axial direction of the take-up shaft 20 and on the bar 136 side of the first rack 142. It is formed corresponding to the lock base gear 126.

  Further, a plurality of engaging teeth 146 are formed at regular intervals along the longitudinal direction of the rack base 140 on the surface of the rack base 140 and the bar 136 opposite to the side wall 16. A one-way clutch 148 constituting a rotation forcing means is provided on the side of the rack bar 138 corresponding to the engaging teeth 146 as a reverse return preventing means. The one-way clutch 148 includes a body 150. A restriction piece 152 is rotatably attached to the body 150. The restricting piece 152 is rotated by a pressing force from the cylinder 134 side, and when such a pressing force is eliminated, the restricting piece 152 returns to its original position by a biasing force of a biasing means such as a spring.

  However, even if a load on the side opposite to the cylinder 134 acts on the regulating piece 152, the regulating piece 152 is engaged with the body 150 so as not to rotate. The restricting piece 152 faces the engaging teeth 146 along the sliding direction of the bar 136. When the engaging teeth 146 presses the restricting piece 152 from the cylinder 134 side, the restricting piece 152 rotates. The engaging teeth 146 that are in contact with the restricting piece 152 can further move away from the cylinder 134. However, since the restriction piece 152 does not rotate due to a load from the side opposite to the cylinder 134, when the engaging tooth 146 contacts the restriction piece 152 from the opposite side to the cylinder 134, the side of the cylinder 134 is further increased. The engaging tooth 146 cannot move.

<Operation and Effect of Second Embodiment>
Next, the operation and effect of the present embodiment will be described.

  In the seat belt retractor 110, when an acceleration sensor (not shown) detects a sudden deceleration state of the vehicle, a control unit such as an ECU activates the gas generation unit of the pretensioner 132. When gas is generated from the gas generating means of the pretensioner 132, the piston in the cylinder 134 slides by this gas pressure, and the bar 136 is pushed out of the cylinder 134. When the bar 136 slides in this way, as shown in FIG. 10, the first rack 142 is engaged with the take-up shaft side gear 40, and the take-up shaft side gear 40 is rotated in the take-up direction.

  Next, when the bar 136 is further pushed out from the cylinder 134 in this state, as shown in FIG. 11, the meshing between the first rack 142 and the take-up shaft side gear 40 is canceled and the second rack 144 and the lock base gear are released. Engagement with 126 is started. As a result, a rotational force in the winding direction is applied to the lock base 124. The rotational force in the winding direction applied to the lock base 124 is transmitted to the winding shaft 20 via the torsion bar 116, and this also rotates the winding shaft 20 in the winding direction.

  When the take-up shaft 20 rotates in the take-up direction in this way, the webbing 24 is taken up by the take-up shaft main body portion 22 from the base end side in the longitudinal direction. Thus, the body of the passenger wearing the webbing 24 is firmly restrained by the webbing 24 by winding the webbing 24.

  Further, as described above, when the second rack 144 and the lock base gear 126 are engaged with each other and the bar 136 is further slid, the restriction pieces 152 of the one-way clutch 148 are sequentially formed from the engaging teeth 146 located on the front end side of the rack base 140. From the side of the cylinder 134. As described above, when the restricting piece 152 receives a pressing force from the cylinder 134 side, the restricting piece 152 rotates so as to be detached from the slide locus of the engaging tooth 146, so that the engaging tooth 146 becomes the restricting piece. Even if it abuts on 152, the bar 136 is pushed out of the cylinder 134 and slides, and the lock base 124 rotates in the winding direction without any trouble.

  On the other hand, in the state where the take-up shaft main body 22 is wound up as described above, for example, the occupant's body pulls the webbing 24 when the occupant's body tries to move inertially due to the sudden deceleration of the vehicle. When the pulling force tries to rotate the lock base 124 in the pull-out direction via the winding shaft 20 and the torsion bar 116, the lock base 124 tries to slide the rack bar 138 in the direction in which the bar 136 is pushed into the cylinder 134. However, when the rack bar 138 tries to slide in this way, the restricting piece 152 interferes with the engaging teeth 146.

  As described above, the restricting piece 152 does not rotate even when the pressing force on the side opposite to the cylinder 134 is received, and therefore, the restricting piece 152 does not separate from the slide locus of the engaging tooth 146. For this reason, since the engaging teeth 146 interfered with the restricting piece 152 cannot move further to the cylinder 134 side, the lock base 124 cannot rotate in the pull-out direction, and consequently the rotation of the winding shaft 20 in the pull-out direction. Be regulated. For this reason, in this state, the webbing 24 cannot be pulled out from the take-up shaft main body 22, the occupant's body is firmly held by the webbing 24, and the inertial movement of the occupant's body toward the vehicle front side is effectively performed. Be regulated.

  Further, the rotational force of the take-up shaft 20 in the pull-out direction due to the occupant's body pulling the webbing 24 in the state where the engaging teeth 146 are interfered with the restriction piece 152 in this way is the mechanical force of the variable portion 122. When the strength is exceeded, torsional deformation occurs in the variable portion 122 so that the coupling portion 118 rotates in the pull-out direction with respect to the coupling portion 32. The take-up shaft 20 can be rotated in the pull-out direction by the torsional deformation of the variable portion 122, and the webbing 24 is pulled out from the take-up shaft main body portion 22 by an amount allowed to rotate in the pull-out direction of the take-up shaft 20. For this reason, the occupant can inertially move forward of the webbing 24 from the take-up shaft main body 22 and a part of the energy of the pulling force of the occupant's body pulling the webbing 24 is twisted by the variable part 122. It is absorbed by deformation.

  Here, in the seat belt retractor 110, when the winding shaft 20 is rotated in the winding direction, a rotational force in the winding direction is applied to the torsion bar 116, but a rotational force in the winding direction is applied to the torsion bar 116. Before starting, the rotational force in the winding direction is applied to the winding shaft side gear 40 of the winding shaft 20 and the winding shaft 20 has already been rotated in the winding direction. A large rotational torque immediately after the start of rotation when rotating the winding shaft 20 in the winding direction is not applied to the torsion bar 116. For this reason, torsional deformation does not occur in the torsion bar 116 when the winding shaft 20 is rotated in the winding direction.

  Further, the restriction piece 152 of the body 150 restricts the movement of the engaging teeth 146 toward the cylinder 134 in a state where the second rack 144 is engaged with the lock base gear 126, so that the webbing 24 from the winding shaft 20 is moved. Since it is used for holding the coupling portion 32 side when the drawer is restricted and the torsion bar 116 is torsionally deformed, the configuration of the lock of the end portion on the side wall 16 side of the torsion bar 116 is simple. become.

  In the present embodiment, the engaging teeth 146 are provided on one side surface along the width direction of the rack bar 138. However, the first rack 142 and the first rack 142 are arranged along the thickness direction of the rack bar 138. Engaging teeth 146 are provided on the surface opposite to the side where the two racks 144 are formed, and the first rack 142 and the second rack 144 are provided along the thickness direction of the rack bar 138 corresponding to the engaging teeth 146. It is good also as a structure which arrange | positions the body 150 on the opposite side to the side in which this was formed. In such a configuration, the overall size of the seat belt retractor 110 along the axial direction of the take-up shaft 20 can be shortened, which contributes to downsizing of the seat belt retractor 110.

  In addition, for example, the rack base 140 is not formed on the side of the first rack 142 along the width direction of the rack bar 138, and the first rack 142, the second rack 144, and the engagement teeth 146 are not formed. The rack base portion 140 may not be formed, and the rack bar 138 can be reduced in weight by such a configuration.

  Further, in the first embodiment, when the gas generation means of the pretensioner 42 is operated, the fitting insertion hole 36 is drawn into the cylinder 44. However, as in the pretensioner 132 in the second embodiment. Furthermore, the gas insertion means may be configured to operate so that the fitting insertion hole 36 is pushed out from the cylinder 44 by the gas pressure generated by the gas generating means. Further, the pretensioner 132 of the second embodiment may be configured to operate like the pretensioner 42 of the first embodiment.

It is front sectional drawing which shows the outline of a structure of the seatbelt retractor which concerns on the 1st Embodiment of this invention. It is front sectional drawing corresponding to FIG. 1 which shows the state which the 2nd lock pawl slid so that mesh | engagement of the 2nd lock pawl and the lock base was impossible. It is a side view which shows the structure of a rotation forced means. FIG. 4 is a side view corresponding to FIG. 3 showing a state in which the first rotation forcing member of the rotation forcing means rotates the take-up shaft side gear in the take-up direction. It is a side view corresponding to FIG. 3 which shows the state of the rotation forced means just before starting holding | maintenance of an energy forced member. FIG. 4 is a side view corresponding to FIG. 3 showing a state in which the energy forcing member is held by a rotation forcing means. It is a side view which shows the structure of the lock base of the 2nd lock pawl and the 2nd lock pawl side. It is front sectional drawing which shows the outline of a structure of the seatbelt retractor which concerns on the 2nd Embodiment of this invention. It is a side view which shows the structure of a rotation forced means. FIG. 10 is a side view corresponding to FIG. 9 showing a state where the first rotation forcing member of the rotation forcing means rotates the take-up shaft side gear in the take-up direction. FIG. 10 is a side view corresponding to FIG. 9 showing a state where the second rotation forcing member of the rotation forcing means rotates the energy absorbing member side gear in the winding direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Seat belt retractor 20 Winding shaft 22 Winding shaft main body part 24 Webbing 26 Torsion bar (energy absorption member)
28 Coupling part 40 Winding shaft side gear 42 Pretensioner (rotation forcing means)
48 racks (first rotation forcing member)
52 Lock pawl (rotation forcing means)
110 Seat belt retractor 116 Torsion bar (energy absorbing member)
118 Coupling portion 126 Lock base gear (energy absorbing member side gear)
132 Pretensioner (Forced rotation)
142 First rack (first rotation forcing member)
144 Second rack (second rotation forcing member)
148 One-way clutch (rotation forcing means)

Claims (2)

The longitudinal base end portion of the long strip webbing is locked, and has a winding shaft main body portion that winds the webbing by rotating in one winding direction around its own axis and the winding shaft main body A take-up shaft in which a take-up shaft side gear is formed coaxially at one axial end of the portion;
An energy absorbing member in which a coupling portion is fixed to the winding shaft between the other axial end portion of the winding shaft main body portion and an intermediate portion;
A first rotation forcing member that rotates the winding shaft side gear in the winding direction by displacing in a state of being engaged with the winding shaft side gear and displaces the first rotation forcing member by operating. In addition, after the first rotation forcing member rotates the winding shaft side gear by a certain angle, the energy absorbing member is engaged directly or indirectly with the energy absorbing member at a portion different from the coupling portion. Rotation forcing means to regulate the rotation of the
A seat belt retractor comprising: An energy absorbing member side gear that is coaxial with the winding shaft main body is provided integrally with the energy absorbing member at a portion different from the coupling portion, and
After the displacement of the first rotation forcing member is started, the rotation forcing includes the second rotation forcing member that meshes with the energy absorbing member side gear and forcibly rotates the energy absorbing member side gear in the winding direction. The seat belt retractor according to claim 1, which constitutes means.

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