Patent Publication Number: US-2007120002-A1

Title: Webbing take-up device

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority under 35 USC 119 from Japanese Patent Application No. 2005-345620, the disclosure of which is incorporated by reference herein.  
     BACKGROUND  
      1. Technical Field  
      The present invention relates to a webbing take-up device that configures a vehicular seat belt device.  
      2. Related Art  
      As disclosed in Japanese Patent Application Laid-open No. 2005-178415, for example, a webbing take-up device is known which includes: a cylindrical spool onto which a webbing is taken up; a torsion bar (energy absorbing member) that is housed inside the spool, with one axial-direction end portion of the torsion bar being disposed on one axial-direction end side of the spool and the other axial-direction end portion of the torsion bar being coupled to the other axial-direction end portion of the spool; a lock gear that is attached, so as to be incapable of relative rotation, to the one axial-direction end portion of the torsion bar; a pretensioner mechanism that is capable of rotating the lock gear in a webbing take-up direction; and a lock mechanism that is capable of inhibiting rotation of the lock gear in a webbing pullout direction.  
      Because this webbing take-up device has a configuration where the pretensioner mechanism and the lock mechanism are both disposed on the one axial-direction end side of the spool, another mechanism may be added to the other axial-direction end side of the spool.  
      However, because this webbing take-up device has a configuration where the drive force of the pretensioner mechanism is transmitted to the spool via the torsion bar, the deformation load of the torsion bar cannot be set lower than the take-up load of the webbing by the pretensioner mechanism.  
     SUMMARY  
      The present invention provides a webbing take-up device where both the pretensioner mechanism and the lock mechanism may be disposed on one end side of the spool and where the deformation load of the energy absorbing member may be set regardless of the take-up load of the webbing by the pretensioner mechanism.  
      A webbing take-up device of a first aspect of the invention provides a webbing take-up device comprising a spool that includes an outer peripheral portion onto which a webbing for restraining a passenger is taken up; a torsionally deformable energy absorbing member that is housed inside the spool, with one end portion of the energy absorbing member being disposed on one end side of the spool and another end portion of the energy absorbing member being coupled to the other end side of the spool; a lock mechanism that is disposed on the one end side of the spool and inhibits rotation of the one end portion of the energy absorbing member in a webbing pullout direction when actuated; and a pretensioner mechanism that comprises a rotating member rotatably supported on the one end portion of the energy absorbing member, a drive source capable of rotating the rotating member in a webbing take-up direction, and a coupling member that couples together the rotating member and the spool at least when the rotating member rotates in the webbing take-up direction and which releases the coupling together of the rotating member and the spool when the energy absorbing member is torsionally deformed.  
      According to this aspect, when the rotating member is rotated in the webbing take-up direction by the drive source of the pretensioner mechanism, the rotational force is transmitted to the spool via the coupling member, and the spool is rotated in the webbing take-up direction. Further, when the lock mechanism is actuated, rotation of the one end portion of the energy absorbing member in the webbing pullout direction is inhibited, and rotation of the spool in the webbing pullout direction is inhibited. In this state, when a load equal to or greater than a predetermined value acts on the spool from the passenger via the webbing, the energy absorbing member is torsionally deformed, and the coupling together of the rotating member and the spool by the coupling member is released. For this reason, the spool rotates in the webbing pullout direction independent of the rotating member, and the webbing is pulled out. Thus, the load (energy) acting on the passenger is absorbed.  
      In this webbing take-up device, the pretensioner mechanism and the lock mechanism are both disposed on the one end side of the spool, but because the rotating member and the spool are coupled together by the coupling member when the drive source of the pretensioner mechanism is actuated, that is, when the rotating member rotates in the webbing take-up direction, the rotational force of the rotating member is directly transmitted to the spool via the coupling member and not via the energy absorbing member. Consequently, the deformation load of the energy absorbing member may be set regardless of the take-up load of the webbing by the pretensioner mechanism.  
      In this aspect, the coupling member may be disposed between, so as to bridge, the rotating member and the spool and may be displaced by relative rotation between the spool and the one end portion of the energy absorbing member such that the coupling together of the rotating member and the spool is released.  
      According to this aspect, when the spool and the one end portion of the energy absorbing member relatively rotate, the coupling member bridging the rotating member and the spool is displaced, and the coupling together of the rotating member and the spool is released.  
      In this aspect, at least one of the spool or the energy absorbing member may include a breaking portion that is disposed between, so as to bridge, the spool and the one end portion of the energy absorbing member to couple together the spool and the one end portion of the energy absorbing member, and is broken when the energy absorbing member is torsionally deformed.  
      According to this aspect, because relative rotation between the spool and the one end portion of the energy absorbing member is regulated by the breaking portion, rotation of the spool in the webbing pullout direction may be reliably restricted when rotation of the one end portion of the energy absorbing member in the webbing pullout direction is inhibited by the lock mechanism, and the coupling member may be prevented from being unnecessarily displaced. Further, because the breaking portion is broken when the energy absorbing member is torsionally deformed, relative rotation between the spool and the one end portion of the energy absorbing member, that is, displacement of the coupling member is enabled.  
      In this aspect, the webbing take-up device may further comprise a relative rotation regulating member that is disposed between, so as to bridge, the rotating member and the one end portion of the energy absorbing member couple together both the rotating member and the one end portion of the energy absorbing member, and is displaced by relative rotation between the rotating member and the one end portion of the energy absorbing member, and to release the coupling together of the rotating member and the one end portion of the energy absorbing member, wherein the coupling member couples together the rotating member and the spool when the rotating member and the one end portion of the energy absorbing member relatively rotate.  
      According to this aspect, because relative rotation between the spool and the one end portion of the energy absorbing member is regulated by the relative rotation regulating member, rotation of the spool in the webbing pullout direction may be reliably restricted when rotation of the one end portion of the energy absorbing member in the webbing pullout direction is inhibited by the lock mechanism. On the other hand, when the rotating member is rotated in the webbing take-up direction by the drive source and the rotating member and the one end portion of the energy absorbing member relatively rotate, the coupling together of the spool and the one end portion of the energy absorbing member by the relative rotation regulating member is released, and the rotating member and the spool are coupled together by the coupling member. Thus, the rotational force of the rotating member is transmitted to the spool via the coupling member.  
      In this aspect, at least one of the rotating member and the energy absorbing member may include a breaking portion that is disposed between, so as to bridge, the rotating member and the one end portion of the energy absorbing member to couple together the rotating member and the one end portion of the energy absorbing member, and is broken when the rotating member rotates.  
      According to this aspect, because relative rotation between the rotating member and the one end portion of the energy absorbing member is regulated by the breaking portion, the relative rotation regulating member may be prevented from being unnecessarily displaced. Further, because the breaking portion breaks when the rotating member is rotated by the drive source, relative rotation between the rotating member and the one end portion of the energy absorbing member is allowed, and displacement of the relative rotation regulating member is enabled.  
      In this aspect, relative rotation between the spool and the one end portion of the energy absorbing member may occur by torsional deformation of the energy absorbing member.  
      According to this aspect, when the spool and the one end portion of the energy absorbing member relatively rotate as a result of the energy absorbing member being torsionally deformed, the coupling member bridging the rotating member and the spool is displaced, and the coupling together of the rotating member and the spool is released.  
      As described above, in the webbing take-up device pertaining to the present invention, the pretensioner mechanism and the lock mechanism may both be disposed on one end side of the spool, and the deformation load of the torsion bar may be set regardless of the take-up load of the webbing by the pretensioner mechanism. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:  
       FIG. 1  is an exploded perspective view showing the configuration of a webbing take-up device pertaining to a first exemplary embodiment of the present invention;  
       FIG. 2  is a cross-sectional view showing the configuration of relevant portions of the webbing take-up device pertaining to the first exemplary embodiment of the present invention;  
       FIG. 3  is an exploded perspective view showing the configuration of peripheral members including a spool and a sleeve of the webbing take-up device pertaining to the first exemplary embodiment of the present invention;  
       FIG. 4  is a cross-sectional view showing the configuration of peripheral members including the spool and the sleeve of the webbing take-up device pertaining to the first exemplary embodiment of the present invention;  
       FIG. 5  is a plan view showing a partial configuration of a slide pin and a lock gear of the webbing take-up device pertaining to the first exemplary embodiment of the present invention;  
       FIG. 6  is a cross-sectional view along line  3 - 3  of  FIG. 4 ;  
       FIG. 7  is a cross-sectional view corresponding to  FIG. 6  showing a state where a rotational force transmitting member is displaced;  
       FIG. 8  is a cross-sectional view showing the configuration of peripheral members including a spool and a sleeve of a webbing take-up device pertaining to a second exemplary embodiment of the present invention;  
       FIG. 9  is a plan view showing a partial configuration of the sleeve and a slide pin of the webbing take-up device pertaining to the second exemplary embodiment of the present invention;  
       FIG. 10A  is a cross-sectional view along line  5 - 5  of  FIG. 8 , and  FIG. 10B  is a cross-sectional view along line  7 - 7  of  FIG. 8 ; and  
       FIG. 11A  is a cross-sectional view corresponding to  FIG. 10A  showing a state where a breaking portion is broken, and  FIG. 11B  is a cross-sectional view corresponding to  FIG. 10B  showing a state where a first rotational force transmitting member is displaced. 
    
    
     DESCRIPTION  
     First Exemplary Embodiment  
      In  FIG. 1 , a webbing take-up device  10  pertaining to a first exemplary embodiment of the present invention is shown in an exploded perspective view. In  FIG. 2 , the configuration of the webbing take-up device  10  is shown in a cross-sectional view. It will be noted that, in  FIG. 2 , illustration of some configural members is omitted for convenience of description. Additionally, in some of the figures, the directions with respect to the webbing take-up device  10  is described as one side and the other side both are indicated as an arrow respectively.  
      The webbing take-up device  10  is disposed with a plate-like frame  12 , which is substantially U-shaped when seen from above, and the frame  12  is fixed inside a vehicle interior. A coupling piece  14  is disposed between, so as to bridge, one side wall  12 A and other side wall  12 B of the frame  12 . The coupling piece  14  is fixed inside the vehicle interior, and an insertion hole  16  is formed in the coupling piece  14 . A substantially circular through hole  15  is formed in the one side wall  12 A of the frame  12 , and a circular through hole  13  is formed in the other side wall  12 B.  
      A circular cylinder-shaped spool  18  serving as a take-up shaft is supported, so as to be freely rotatable, between the one side wall  12 A and the other side wall  12 B of the frame  12 . A proximal end portion of a long band-like webbing  20  for restraining a passenger is locked to the spool  18  by a circular column-shaped shaft  22 . When the spool  18  is rotated in one direction about its axis (this direction will be called the “take-up direction” below; see arrow A in  FIG. 3 ), the webbing  20  is taken up from its proximal end side onto the outer peripheral portion of the spool  18 . When the webbing  20  is pulled from its distal end side, the webbing  20  is pulled out while the spool  18  rotates (the rotational direction of the spool  18  when the webbing  20  is pulled out will be called the “pullout direction” below; see arrow B in  FIG. 3 ).  
      A torsion bar  24  that configures an energy absorbing member of a force limiter mechanism is disposed inside (in the axial center portion of) the spool  18 . The torsion bar  24  is formed by a metal material such as steel and includes a torsion deformation portion  23 , which is torsionally deformable when a torsional load equal to or greater than a predetermined value is applied thereto, and a spindle portion  25 , which is disposed coaxially and integrally with one axial-direction end portion (in  FIG. 2 , the left end portion) of the torsion deformation portion  23 . The spindle portion  25  penetrates, without contacting, the through hole  15  in the one side wall  12 A and protrudes outward (one side) of the frame  12 .  
      A screw member  26  is screwed into the other axial-direction end portion (in  FIG. 2 , the right end portion) of the torsion deformation portion  23 , and the other axial-direction end portion of the torsion deformation portion  23  and the other axial-direction end portion (in  FIG. 2 , the right end portion) of the spool  18  are integrally coupled together by the screw member  26 . Thus, the torsion bar  24  rotates integrally with the spool  18 .  
      A lock gear  28  that configures the energy absorbing member of the force limiter mechanism is disposed on the one axial-direction side (in  FIG. 2 , the left side) of the spool  18 . The lock gear  28  is disposed inside the through hole  15  in the one side wall  12 A and is locked to the one axial-direction end portion of the torsion deformation portion  23 . The lock gear  28  rotates integrally with the torsion bar  24  and the spool  18  other than when the torsion deformation portion  23  is torsionally deformed. As shown in  FIG. 3 , ratchet teeth  30  are formed on the outer periphery of the lock gear  28 .  
      As shown in  FIG. 4 , a circular shear pin insertion hole  120  that opens to the other side of the lock gear  28  is formed in the outer peripheral portion of the lock gear  28 . A circular column-shaped shear pin  122  serving as a breaking portion that protrudes from the one axial-direction end portion of the spool  18  is inserted into the shear pin insertion hole  120 . The shear pin  122  couples together the spool  18  and the lock gear  28  and regulates the relative rotation of both, but when torque equal to or greater than a predetermined value acts between the spool  18  and the lock gear  28  and the torsion deformation portion  23  of the torsion bar  24  is torsionally deformed, the shear pin  122  breaks (shears) and releases the coupling together of the spool  18  and the lock gear  28 .  
      A substantially keyhole-shaped slide pin retention hole  124  that penetrates the lock gear  28  along its axial direction is formed in the lock gear  28 . The keyhole-shaped slide pin retention hole  124  is provided further toward inner diameter side of the lock gear  28  with respect to the shear pin insertion hole  120 . As shown in  FIG. 5 , the slide pin retention hole  124  includes a substantially circular small-diameter hole portion  126  and a substantially circular large-diameter hole portion  128  that is continuous with the small-diameter hole portion  126 . The small-diameter hole portion  126  and the large-diameter hole portion  128  are lined up along the circumferential direction of the lock gear  28 , with the large-diameter hole portion  126  being disposed further in the pullout direction with respect to the small-diameter hole portion  126 . In a state where the shear pin  122  has been inserted into the shear pin insertion hole  120  in the lock gear  28 , the small-diameter hole portion  126  is disposed facing a circular slide pin housing hole  130  formed in the one end portion of the spool  18 . The inner peripheral portion of the slide pin housing hole  130  is formed in a spherical shape.  
      A circular sleeve housing hole  132  that opens to the one side of the lock gear  28  is formed in the center portion of the lock gear  28  (see  FIG. 3 ), and a sleeve  134  formed in a discoid shape serving as a rotating member that configures part of a later-described pretensioner mechanism  56  is housed inside the sleeve housing hole  132 . The sleeve  134  is rotatably supported on one end portion of the torsion deformation portion  23 . A circular knurl hole  32  that opens to the one side of the sleeve  134  is formed in the center portion of the sleeve  134 , and a knurl surface  34  is formed on the entire inner peripheral surface of the knurl hole  32  as a result of the entire inner peripheral surface of the knurl hole  32  being knurled.  
      A slide pin insertion hole  136  that penetrates the sleeve  134  along its axial direction is formed in the outer peripheral portion of the sleeve  134 . The slide pin insertion hole  136  is disposed facing the small-diameter hole portion  126  of the slide pin retention hole  124 .  
      Here, as shown in  FIG. 6 , a slide pin  138  formed in a substantially circular column shape serving as a coupling member that configures part of the later-described pretensioner mechanism  56  is housed inside the slide pin insertion hole  136 , the slide pin retention hole  124 , and the slide pin housing hole  130 . The slide pin  138  has a stepped shape where large-diameter portions  140  and  142  are formed at both axial-direction end portions and where a small-diameter portion  144  is formed at an axial-direction intermediate portion. The large-diameter portion  140  is disposed inside the slide pin insertion hole  136 , the small-diameter portion  144  is disposed inside the small-diameter hole portion  126  of the slide pin retention hole  124 , and the large-diameter portion  142  is disposed inside the slide pin housing hole  130 .  
      The outer diameter dimensions of the large-diameter portions  140  and  142  are formed larger than the inner diameter dimension of the small-diameter hole portion  126  and smaller than the inner diameter dimension of the large-diameter hole portion  128 . Displacement of the slide pin  138  along its axial direction is ordinarily regulated as a result of the large-diameter portion  140  and the large-diameter portion  142  engaging with the hole edge portion of the small-diameter hole portion  126 . In this state, the sleeve  134  and the spool  18  are coupled together via the slide pin  138 , so that when the sleeve  134  rotates, this rotational force is transmitted to the spool  18  via the slide pin  138  (see arrow P in  FIG. 6 ).  
      When the spool  18  and the sleeve  134  relatively rotate a predetermined amount in the pullout direction with respect to the lock gear  28  such that the slide pin insertion hole  136  and the slide pin housing hole  130  face the large-diameter hole portion  128  of the slide pin retention hole  124 , the above-described regulation of displacement of the slide pin  138  is released and the large-diameter portion  142  is pressed against the inner peripheral surface of the slide pin housing hole  130 , whereby the slide pin  138  is displaced away from the spool  18  as shown in  FIG. 7  (see arrow D in  FIG. 7 ). Thus, the coupling together of the sleeve  134  and the spool  18  by the slide pin  138  is released.  
      As shown in  FIG. 1 , a biasing mechanism  36  is disposed on the other side (in  FIG. 2 , the right side) of the frame  12 . The biasing mechanism  36  includes a spring seat  38 , and the spring seat  38  is attached to the outside of the other side wall  12 B of the frame  12 . The spring seat  38  covers the other side surface of the spool  18  in a state where the screw member  26  protrudes toward the other side. The other side of the spring seat  38  is covered by a spring cover  40 , and the spring cover  40  is attached to the outside of the other side wall  12 B of the frame  12 . A substantially circular column-shaped recessed portion  42  is formed in the spring cover  40 , and the recessed portion  42  opens toward the one side.  
      A spiral spring  44  is disposed inside the recessed portion  42  of the spring cover  40 , and an outer side end of the spiral spring  44  is fixed to the inner peripheral surface of the recessed portion  42 . An inner side end of the spiral spring  44  is fixed to the screw member  26  such that the spiral spring  44  biases the torsion bar  24 , the spool  18 , and the lock gear  28  in the take-up direction via the screw member  26 .  
      A lock member  46  that configures part of a later-described lock mechanism  82  is disposed between, so as to bridge, the one side wall  12 A and the other side wall  12 B of the frame  12 , and a lock plate  48  is disposed on one end portion (in  FIG. 2 , the left end portion) of the lock member  46 . The lock plate  48  is supported, so as to be freely pivotable, at one end on a lower portion of a gear case  52  described below, and the lock plate  48  is disposed diagonally below the lock gear  28 . Lock teeth  50  are formed on the other end of the lock plate  48 , and the lock plate  48  is configured to be pivotable between a position where the lock teeth  50  are separated from the ratchet teeth  30  of the lock gear  28  and a position where the lock teeth  50  are meshed with the ratchet teeth  30  of the lock gear  28 .  
      In the state where the lock teeth  50  of the lock plate  48  are meshed with the ratchet teeth  30  of the lock gear  28 , rotation of the lock gear  28 , the torsion bar  24 , and the spool  18  in the pullout direction is inhibited. Moreover, in this locked state, the load acting on the spool  18  from the webbing  20  is transmitted to the frame  12  via the torsion bar  24 , the lock gear  28 , and the lock plate  28  (the lock member  46 ). That is, in this locked state, the load acting on the spool  18  is supported by the frame  12 . It will be noted that the lock plate  48  is ordinarily disposed in the position where the lock teeth  50  are separated from the ratchet teeth  30  of the lock gear  28 .  
      The gear case  52  is disposed on the outside of the one side wall  12 A of the frame  12 , and the gear case  52  covers the one side of the lock gear  28 . A circular hole  54  is formed in the center portion of the gear case  52 , and the circular hole  54  allows the knurl hole  32  in the sleeve  134  to be exposed. The circular hole  54  is formed with a sufficiently larger diameter than the spindle portion  25  of the torsion bar  24 , and the spindle portion  25  coaxially penetrates the circular hole  54 .  
      The pretensioner mechanism  56  is disposed on the outside of the one side wall  12 A of the frame  12  (opposite the spool  18 ). As shown in  FIG. 3 , the pretensioner mechanism  56  includes a pinion  58  that is disposed on the one side of the gear case  52  and configures a rotating member. The pinion  58  is formed by a metal material such as steel and includes a gear portion  60  having pinion teeth formed on peripheral portion thereof  
      A circular cylinder-shaped cam portion  62  is coaxially and integrally disposed on the other side of the gear portion  60 , and recesses and protrusions are alternately formed on the outer periphery of the cam portion  62 . The cam portion  62  is inserted into the knurl hole  32  via the circular hole  54  in the gear case  52  but does not contact the knurl surface  34 , and the sleeve  134  is configured to be rotatable independent of the pinion  58 . The cam portion  62  corresponds to a later-described clutch plate  64 .  
      A circular cylinder-shaped rotating spindle portion  61  is coaxially and integrally disposed on the one side of the gear portion  60 . The rotating spindle portion  61  penetrates a circular hole  81  formed in a later-described cover plate  80  and is locked by a snap ring  83 , and the pinion  58  is rotatably supported by the cover plate  80 .  
      A circular hole portion  63  that penetrates the pinion  58  (the gear portion  60 , the cam portion  62 , and the rotating spindle portion  61 ) along its axial direction is formed in the axial center portion of the pinion  58 , and the spindle portion  25  of the torsion bar  24  coaxially penetrates the hole portion  63 .  
      As shown in  FIG. 1 , the inner diameter dimension of the hole portion  63  in the pinion  58  is formed sufficiently larger in comparison to the outer diameter dimension of the spindle portion  25  of the torsion bar  24 , and an annular gap is formed between the inner peripheral surface of the hole portion  63  and the outer peripheral surface of the spindle portion  25 . That is, the spindle portion  25  penetrates, without contacting, the hole portion  63 .  
      As shown in  FIG. 3 , the pretensioner mechanism  56  includes the clutch plate  64 , and the clutch plate  64  is disposed between the gear case  52  and the pinion  58 . Plural mesh claws  66  are formed in the center of the clutch plate  64 , and the mesh claws  66  protrude toward the other side from the clutch plate  64 . The mesh claws  66  fit together with the recessed portions in the cam portion  62 ; thus, the clutch plate  64  is attached to the pinion  58 . The mesh claws  66  are inserted together with the cam portion  62  into the knurl hole  32  via the circular hole  54  in the gear case  54  but do not contact the knurl surface  34 , and the sleeve  134  is configured to be rotatable independent of the clutch plate  64 .  
      As shown in  FIG. 1 , the pretensioner mechanism  56  includes a drive source  67 . The drive source  67  includes a substantially L-shaped circular cylinder  68 , and the cylinder  68  is fixed to the outside of the one side wall  12 A of the frame  12  below the pinion  58 . At the lower side end of the cylinder  68 , a gas generator  70  is disposed and a bottomed circular cylinder-shaped generator cap  72  is fixed, and the gas generator  70  closes off the lower side end of the cylinder  68  in a state where it is covered by the generator cap  72 .  
      The drive source  67  includes a piston  74 , and the piston  74  is inserted into the cylinder  68  from the upper end of the cylinder  68 . An O ring  76  is disposed on the lower end of the piston  74 , and the O ring  76  seals the space between the lower end of the piston  74  and the cylinder  68 . Moreover, a rack  78  is formed on the piston  74  at a site other than at the lower end.  
      Moreover, the pretensioner mechanism  56  includes the cover plate  80 , which is formed in a substantially triangular column container shape by a metal material, and the cover plate  80  is fixed by plural screws  79  to the outside of the one side wall  12 A. As mentioned previously, the pinion  58  is rotatably supported in the circular hole  81  in the cover plate  80 , and the spindle portion  25  penetrating the hole portion  63  in the pinion  58  protrudes toward the one side of the cover plate  80 . The other side surface and the lower surface of the cover plate  80  are open, and the cover plate  80  houses inside the pinion  58 , the clutch plate  64 , and the upper portion of the piston  74 , and sandwiches the gear case  52  between itself and the one side wall  12 A.  
      The lock mechanism  82  is disposed on the one side (opposite the frame  12  with respect to the cover plate  80 ) of the pretensioner mechanism  56  (the cover plate  80 ). The lock mechanism  82  includes a box-like sensor holder  84  whose other side is open. The sensor holder  84  is formed by a resin material, and plural unillustrated lock claws formed on the outer peripheral portion of the open side of the sensor holder  84  fit and lock together with unillustrated lock protrusions and lock protrusions  93  formed on the outer peripheral portion of the one side wall  12 A, whereby the sensor holder  84  is attached to the one side wall  12 A opposite the spool  18  in a state where the sensor holder  84  does not contact the cover plate  80 .  
      As shown in  FIG. 1 , a circular bearing hole  85  is formed in the bottom wall of the sensor holder  84 , and the one end portion of the spindle portion  25  (the one end portion of the torsion bar  24 ) that penetrates, without contacting, the hole portion  63  in the pinion  58  is supported, so as to be freely rotatable, by the bearing hole  85 . That is, the one end portion of the torsion bar  24  is supported independent of the pinion  58 .  
      The one side of the sensor holder  84  is covered by a box-like sensor cover  86  whose other side is open, and the sensor cover  86  is fixed to the sensor holder  84  and the one side wall  12 A of the frame  12 .  
      An acceleration sensor  88  is retained in the lower portion of the sensor holder  84 , and the acceleration sensor  88  is disposed in the space between the sensor holder  84  and the sensor cover  86 . The acceleration sensor  88  includes a mount  90 . A substantially inverted cone-shaped concave portion is formed in the upper surface of the mount  90 , and a sphere  92  is mounted in the concave portion of the mount  90 . A movable claw  94  is supported, so as to be freely pivotable, above the sphere  92 , and the movable claw  94  is placed on top of the sphere  92 .  
      A V gear  96  is disposed in the space between the sensor holder  84  and the sensor cover  86 , and the V gear  96  is integrally coupled to the one end portion of the spindle portion  25  and rotates integrally with the torsion bar  24 . Ratchet teeth  98  are formed on the outer periphery of the V gear  96 .  
      A rotation sensor  99  is disposed on the one side of the V gear  96  in the space between the sensor holder  84  and the sensor cover  86 . The rotation sensor  99  includes a W pawl  100  rotatably supported on the V gear  96 , and a W mass  102  is fixed to the W pawl  100 . A sensor spring  104  is disposed between, so as to bridge, the V gear  96  and the W pawl  100 , and the sensor spring  104  biases the V gear  96  in the take-up direction with respect to the W pawl  100 .  
      A substantially discoid gear sensor  106  is disposed on the one side of the rotation sensor  99  in the space between the sensor holder  84  and the sensor cover  86 , and the gear sensor  106  is rotatably supported on the one end portion of the spindle portion  25 . A coil spring  108  is disposed between, so as to bridge, the gear sensor  106  and the inner surface of the sensor cover  86 , and the coil spring  108  biases the gear sensor  106  in the take-up direction.  
      An engagement claw  110  is rotatably provided at the one side on the lower portion of the gear sensor  106 . The axis of the center of rotation of the engagement claw  110  is parallel to the axial direction of the torsion bar  24 , and the engagement pawl  110  is configured to be meshable with the ratchet teeth  98  of the V gear  96 . A push piece  112  is formed at the other side on the lower portion of the gear sensor  106 .  
      Next, the action of the present exemplary embodiment will be described.  
      In the webbing take-up device  10  of the above-described configuration, the spiral spring  44  of the biasing mechanism  36  biases the torsion bar  24 , the spool  18 , and the lock gear  28  in the take-up direction via the screw member  26 , whereby the webbing  20  is biased in the direction in which it is taken up onto the spool  18 .  
      The acceleration sensor  88  of the lock mechanism  82  detects that the acceleration of the vehicle (the moving acceleration of the spool  18 ) is equal to or greater than a predetermined acceleration. When the acceleration of the vehicle is equal to or greater than the predetermined acceleration (e.g., when the vehicle suddenly decelerates), the sphere  92  of the acceleration sensor  88  moves and rises in the concave portion of the mount  90  in the direction opposite to the acceleration direction and pushes up the movable claw  94 . Thus, the movable claw  94  causes the engagement claw  110  of the gear sensor  106  to rotate and mesh with the ratchet teeth  98  of the V gear  96 , whereby the gear sensor  106  becomes coupled to the V gear  96 .  
      The rotation sensor  99  of the lock mechanism  82  detects that the pullout acceleration of the webbing  20  (the rotational acceleration of the spool  18  in the pullout direction) is equal to or greater than a specific acceleration. When the pullout acceleration of the webbing  20  is equal to or greater than the specific acceleration, the rotation of the W pawl  100  and the W mass  102  of the rotation sensor  99  in the pullout direction is suppressed by inertia with respect to the V gear  96  that is rotated in the pullout direction via the spool  18  and the torsion bar  24 , whereby the W pawl  100  and the W mass  102  are pivoted with respect to the V gear  96 . Thus, the W pawl  100  causes the engagement claw  110  of the gear sensor  106  to rotate and mesh with the ratchet teeth  98  of the V gear  96 , whereby the gear sensor  106  becomes coupled to the V gear  96 .  
      When the gear sensor  106  becomes coupled to the V gear  96  as described above, the V gear  96  and the gear sensor  106  are rotated somewhat in the pullout direction via the spool  18  and the torsion bar  24  by the pullout load on the webbing  20  from the passenger. In this case, the rotational force of the V gear  96  and the gear sensor  106  is reduced by the biasing force of the sensor spring  104  that has increased due to the inertia of the W pawl  100  and the W mass  102 .  
      When the gear sensor  106  is rotated somewhat in the pullout direction in this manner, the push piece  112  of the gear sensor  106  causes the lock plate  48  of the lock member  46  to pivot toward the lock gear  28 . The pullout load is imparted to the webbing  20  from the passenger and rotational force is imparted in the pullout direction to the spool  18 , the torsion bar  24 , and the lock gear  28 , whereby the lock teeth  50  of the lock plate  48  mesh with the ratchet teeth  30  of the lock gear  28  and rotation of the lock gear  28  in the pullout direction is inhibited. For this reason, rotation in the pullout direction of the spool  18  coupled to the lock gear  28  by the shear pin  122  and the torsion bar  24  is inhibited and the pulling-out of the webbing  20  is inhibited.  
      Further, when the vehicle experiences an emergency (e.g., an occasion such as when the vehicle suddenly decelerates), the gas generator  70  of the pretensioner mechanism  56  generates gas, whereby the piston  74  is caused to rise inside the cylinder  68  together with the O ring  76 , the rack  78  of the piston  74  meshes with the gear portion  60  of the pinion  58 , and the pinion  58  is rotated in the take-up direction. For this reason, the pinion  58  is relatively rotated with respect to the clutch plate  64 , and the mesh claws  66  of the clutch plate  64  are fitted together with the convex portions on the cam portion  62  of the pinion  58 , whereby the mesh claws  66  of the clutch plate  64  are moved outward in the radial direction of the clutch plate  64  and mesh with the knurl surface  34  of the sleeve  134  (the pinion  58  and the sleeve  134  become coupled together). Thus, the sleeve  134  is rotated in the take-up direction integrally with the clutch plate  64  and the pinion  58 .  
      The rotational force of the sleeve  134  in the take-up direction is transmitted to the spool  18  and the lock gear  28  via the slide pin  138 , and the spool  18  and the lock gear  128  are rotated in the take-up direction. Thus, the webbing  20  is taken up onto the spool  18 , slight looseness (slack) of the webbing  20  in the worn state is eliminated, and the force with which the webbing  20  restrains the passenger rises.  
      Moreover, when a load equal to or greater than a predetermined value acts on the spool  18  from the passenger via the webbing  20  when the pretensioner mechanism  56  is actuated in a state where the pulling-out of the webbing is inhibited as mentioned previously, that is, in a state where rotation of the lock gear  28  in the pullout direction is inhibited by the lock member  46 , the torsion deformation portion  23  of the torsion bar  24  is torsionally deformed, the shear pin  122  breaks, and the spool  18  relatively rotates in the pullout direction with respect to the lock gear  28 . Then, when the slide pin insertion hole  136  and the slide pin housing hole  130  face the large-diameter hole portion  128  of the slide pin retention hole  124 , the regulation of displacement of the slide pin  138  by the slide pin retention hole  124  in the lock gear  28  is released. Then, the large-diameter portion  142  is pressed with the inner peripheral surface of the slide pin housing hole  130 , whereby the slide pin  138  is displaced toward the side opposite the spool  18 , and the coupling together of the sleeve  134  and the spool  18  by the slide pin  138  is released. For this reason, the spool  18  is rotated in the pullout direction independent of the lock gear  28  and the sleeve  134  when the torsion deformation portion  23  of the torsion bar  24  is torsionally deformed. Thus, the webbing  20  is pulled out and the load (energy) acting on the passenger from the webbing  20  is absorbed.  
      The webbing take-up device  10  pertaining to the first exemplary embodiment of the present invention has a configuration where the pretensioner mechanism  56  and the lock mechanism  82  are disposed on one axial-direction end side of the spool  18  but, as mentioned previously, because the rotational force of the sleeve  134  of the pretensioner mechanism  56  is directly transmitted to the spool  18  via the slide pin  138  (i.e., is transmitted to the spool  18  not via the torsion bar  24 ), the deformation load of the torsion bar  24  may be set regardless of the take-up load of the webbing  20  by the pretensioner mechanism  56 .  
      It will be noted that, in the webbing take-up device  10  pertaining to the above-described first exemplary embodiment, although a case was described where there was just one slide pin  138 , the invention is not limited to this and may also have a configuration where the sleeve  134  and the spool  18  are coupled together by plural slide pins  138 .  
     Second Exemplary Embodiment  
      Next, a second exemplary embodiment of the present invention will be described. Reference numerals that are the same as those in the preceding first exemplary embodiment will be given to members that are basically the same as those in the preceding first exemplary embodiment, and description of the configurations and action thereof will be omitted.  
      In  FIG. 8 , a partial configuration of a webbing take-up device  150  pertaining to the second exemplary embodiment of the present invention is shown in a cross-sectional view.  
      The webbing take-up device  150  basically has the same configuration as that of the webbing take-up device  10  pertaining to the preceding first exemplary embodiment, but is different in the following respects.  
      A spool  152  of the webbing take-up device  150  basically has the same configuration as that of the spool  18  pertaining to the preceding first exemplary embodiment, but the shear pin  122  is omitted. Further, a circular second slide pin disposition hole  154  that opens to the one side is formed in the one axial-direction end portion of the spool  152 .  
      A lock gear  156  of the webbing take-up device  150  basically has the same configuration as that of the lock gear  28  pertaining to the preceding first exemplary embodiment, but the shear pin insertion hole  120  is omitted. Further, a circular first insertion hole  158  that penetrates the lock gear  156  in its axial direction is formed in the lock gear  156 . The first insertion hole  158  faces the second slide pin disposition hole  154  in the spool  152 , and a second slide pin  160  serving as a relative rotation regulating member that is formed in a circular column shape is housed inside the second slide pin disposition hole  154  and the first insertion hole  158 . In the present exemplary embodiment, the second slide pin  160  serves as a first rotational force transmitting member. A torsion coil spring  162  is housed between the second slide pin  160  and the bottom portion of the second slide pin disposition hole  154 . The torsion coil spring  162  biases the second slide pin  160  toward the one side (side opposite the spool  152 ), and displacement of the second slide pin  160  toward the one side is regulated as a result of the second slide pin  160  abutting against a sleeve  164 . The second slide pin  160  couples together the lock gear  156  and the spool  152  and enables transmission of rotational force between both.  
      The sleeve  164  basically has the same configuration as that of the sleeve  134  pertaining to the preceding first exemplary embodiment, but a slide pin insertion hole  170  formed in the outer peripheral portion of the sleeve  164  is shaped as a long hole whose longitudinal direction is along the circumferential direction of the sleeve  164 , as shown in  FIG. 10 . A predetermined space is disposed between the end portion at the pullout direction side of the slide pin insertion hole  170  and the slide pin  138 . In the present exemplary embodiment, the slide pin  138  serves as a second rotational force transmitting member.  
      As shown in  FIG. 10B , a circular shear pin insertion hole  166  is formed in the end surface at the other side (lock gear  156  side) of the sleeve  164 , and a shear pin  168  serving as a breaking portion that protrudes from the end surface at the one side (sleeve  164  side) of the lock gear  156  is housed in the shear pin insertion hole  166 . The shear pin  168  couples together the sleeve  164  and the lock gear  156  and regulates the relative rotation of both, but when the pretensioner mechanism  56  is actuated, that is, when the sleeve  164  is rotated in the take-up direction by the drive source  67 , the shear pin  168  breaks and releases the coupling together of the sleeve  164  and the lock gear  156 .  
      Moreover, a circular second insertion hole  180  that penetrates the sleeve  164  in its axial direction is formed in the outer peripheral portion of the sleeve  164 . As shown in  FIG. 10B , the second insertion hole  180  is disposed a predetermined amount in the pullout direction side with respect to the first insertion hole  158  in the lock gear  156 .  
      Next, the action of the second exemplary embodiment will be described.  
      In the webbing take-up device  150  of the above-described configuration, the spool  152  and the lock gear  156  are coupled together by the second slide pin  160 , so that when the rotation of the lock gear  156  in the pullout direction is inhibited by the lock member  46  of the lock mechanism  82 , the load acting on the spool  152  is transmitted to the lock gear  156  via the second slide pin  160  (arrow L in  FIG. 10B ), and the rotation of the spool  152  in the pullout direction is inhibited.  
      When the vehicle experiences an emergency (e.g., an occasion such as when the vehicle suddenly decelerates), when the sleeve  164  is rotated in the take-up direction by the drive source  67  of the pretensioner mechanism  56 , the shear pin  168  breaks as shown in  FIG. 11A  and the sleeve  164  relatively rotates with respect to the lock gear  156 . Then, when the end portion at the pullout direction side of the slide pin insertion hole  170  abuts against the large-diameter portion  140  of the slide pin  138 , the sleeve  164  and the spool  152  become coupled together via the slide pin  138 , and the rotational force of the sleeve  164  is transmitted to the spool  152  via the slide pin  138  (arrow P in  FIG. 11A ). Thus, the spool  152  is rotated in the take-up direction, and the webbing  20  is taken up onto the spool  152 .  
      Further, at this time, the sleeve  164  relatively rotates a predetermined amount in the take-up direction with respect to the lock gear  156 , whereby the second insertion hole  180  in the sleeve  164  and the first insertion hole  158  in the lock gear  156  face each other as shown in  FIG. 11B , and the retention of the second slide pin  160  by the sleeve  164  is released. For this reason, the second slide pin  160  is ejected toward the one side of the sleeve  164  by the biasing force of the torsion coil spring  162  (arrow E in  FIG. 11B ), and the coupling together of the lock gear  156  and the spool  152  by the second slide pin  160  is released.  
      Moreover, when a load equal to or greater than a predetermined value acts on the spool  152  from the passenger via the webbing  20  when the pretensioner mechanism  56  is actuated in a state where the pulling-out of the webbing is inhibited as mentioned previously, that is, in a state where rotation of the lock gear  156  in the pullout direction is inhibited by the lock member  46 , the torsion deformation portion  23  of the torsion bar  24  is torsionally deformed and the spool  152  relatively rotates in the pullout direction with respect to the lock gear  156 . Thus, similar to the webbing take-up device  10  pertaining to the preceding first exemplary embodiment, the regulation of displacement of the slide pin  138  by the slide pin retention hole  124  in the lock gear  156  is released, the slide pin  138  is displaced toward the one side of the spool  152 , and the coupling together of the sleeve  164  and the spool  152  by the slide pin  138  is released. For this reason, the torsion deformation portion  23  of the torsion bar  24  is torsionally deformed, whereby the spool  152  is rotated in the pullout direction independent of the lock gear  156  and the sleeve  164 . Thus, the webbing  20  is pulled out and the load (energy) acting on the passenger from the webbing  20  is absorbed.  
      As described above, the webbing take-up device  150  pertaining to the second exemplary embodiment of the present invention also provides action and effects that are basically the same as those of the webbing take-up device  10  pertaining to the preceding first exemplary embodiment. That is, during initial actuation of the pretensioner mechanism, the pulling-out of the webbing is inhibited by the slide pin  138  and the second slide pin  160 . Further, because the sleeve  164  and the spool  152  are coupled together by the slide pin  138  and the second slide pin  160 , the rotational force of the sleeve  164  is directly transmitted to the spool  152  via the slide pin  138  and the second slide pin  160  (i.e., is transmitted to the spool  18  not via the torsion bar  24 ). Thus, the deformation load of the torsion bar  24  may be set to a desired value regardless of the take-up load of the webbing  20  by the pretensioner mechanism  56 .  
      In the webbing take-up devices pertaining to the preceding first exemplary embodiment and second exemplary embodiment, the pretensioner mechanism was configured such that it was coupled to the spool by the slide pin disposed between, so as to bridge, the sleeve and the spool, but the pretensioner mechanism is not limited to this and may also be configured such that it is coupled to the spool at least when it is actuated.