Patent Publication Number: US-7216827-B2

Title: Seatbelt retractor and seatbelt device

Description:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
   The present invention relates to a seatbelt retractor to be installed in a vehicle such as an automobile or the like for retracting a seatbelt with a motor to restrain and protect a passenger and, more specifically, relates to a seatbelt retractor including a clutch mechanism for efficiently retracting a seatbelt with small power consumption. The present invention also relates to a seatbelt device provided with the seatbelt retractor. 
   Conventionally, a seatbelt device is installed in a vehicle such as an automobile or the like, and in case of emergency when great deceleration acts upon a vehicle in a collision or the like, a seatbelt restrains a passenger so as to prevent the passenger from being thrown out of the seat, thereby protecting the passenger. Such a seatbelt device includes a seatbelt retractor for retracting the seatbelt. The seatbelt retractor includes forcing means such as a spiral spring or the like for forcing a spool to rotate in a belt-retracting direction all the times for winding the seatbelt thereon. That is, the seatbelt is wound onto the spool due to the force of the forcing means when the passenger does not wear the seatbelt. 
   On the other hand, the seatbelt is extracted against the force of the forcing means when the passenger wears the seatbelt. The seatbelt retractor has lock means for prohibiting rotation of the spool in a belt-extracting direction in case of emergency such as the aforementioned examples, thereby prohibiting extraction of the seatbelt in case of emergency. Thus, with the seatbelt, the passenger is restrained and protected in a sure manner in case of emergency. 
   In such a conventional seatbelt device, a generally constant belt tension is applied to the seatbelt with the forcing means at the time of wearing the seatbelt. Accordingly, the seatbelt retractor operates generally in a single mode regardless of a situation of the vehicle including the seatbelt device and the surroundings thereof. In this case, while the conventional seatbelt device restrains and protects the passenger in a sure manner in case of emergency as described above, the seatbelt is not controlled so as to provide comfortable wearing for the passenger in situations other than emergency. Furthermore, there is increased demand for a seatbelt wherein the passenger is more stably restrained so as to be protected in a surer manner in case of emergency. 
   Japanese Patent Publication (Kokai) No. 2002-104135 has disclosed a passenger restraining/protecting system in which a motor is provided for controlling rotation of the spool of the seatbelt retractor corresponding to a situation of the vehicle including the seatbelt device and the surroundings thereof so as to adjust belt tension, thereby more efficiently restraining and protecting the passenger, and providing more comfortable wearing for the passenger. 
   In the seatbelt retractor disclosed in Japanese Patent Publication (Kokai) No. 2002-104135, when the motor is not driven, a power transmission path for transmitting the driving force of the motor to the spool is disconnected so that the driving force is not transmitted to the spool, and both the motor and the spool rotate freely. When the motor is driven in the belt-retracting direction (referred to as forward rotational direction) for retracting the seatbelt, the power transmission path is connected through the forward rotation of the motor, thereby transmitting the driving force of the motor to the spool. Accordingly, the seatbelt retractor is controlled so that the spool rotates in the belt-retracting direction so as to retract the seatbelt by the driving force of the motor, thereby increasing the belt tension. Furthermore, in this case, when the motor rotates in the reverse direction for releasing the seatbelt, the power transmission path is disconnected. As a result, both the motor and the spool rotate freely, i.e., the spool is not affected by the driving force of the motor. 
   As described above, in the seatbelt retractor disclosed in Japanese Patent Publication (Kokai) No. 2002-104135, when the motor rotates, the clutch for controlling the power transmission path is connected so as to connect the power transmission path. On the other hand, when the motor rotates in reverse, the clutch is disconnected so as to shut off the power transmission path. 
   In the seatbelt retractor disclosed in Japanese Patent Publication (Kokai) No. 2002-104135, it is necessary to stop the motor after the power transmission path is disconnected and the clutch of the power transmission path turns off. Accordingly, in a conventional seatbelt retractor, a period of time for reverse rotation is set based on a period of time from the start of the reverse rotation of the motor to completion of disconnecting the clutch. In this case, the period of time required for disconnecting the clutch varies according to an operating situation of the retractor. Accordingly, the period of time for the reverse rotation is set to be a maximum period of time required for disconnecting the clutch in every situation. As a result, in every situation, the motor stops driving after completion of disconnecting the clutch in a sure manner. 
   However, when a fixed period of time for the reverse rotation of the motor for disconnecting the clutch is set, the motor rotates in reverse for a relatively long time in most ordinary situations, thereby always generating mechanical noise. While the mechanical noise causes no particular problem in the seatbelt retractor disclosed in Japanese Patent Publication (Kokai) No. 2002-104135, the mechanical noise is preferably suppressed as much as possible. 
   In view of the problems described above, the present invention has been made, and an object of the invention is to provide a seatbelt retractor having a configuration wherein power consumption of the motor is reduced and a mechanical noise is suppressed when the clutch is disconnected. 
   Another object of the invention is to provide a seatbelt device provided with the seatbelt retractor. 
   Further objects and advantages of the invention will be apparent from the following description of the invention. 
   SUMMARY OF THE INVENTION 
   In order to achieve the objects described above, according to a first aspect of the present invention, a seatbelt retractor comprises a spool for winding a seatbelt; a motor for generating rotational torque for rotating the spool; a clutch mechanism for connecting a power transmission path to transmit rotational torque of the motor to the spool in a connected mode and for disconnecting the power transmission path in a disconnected mode; clutch mechanism disconnection detecting means for detecting disconnection of the clutch mechanism; and a motor control device for stopping driving of the motor according to a detection signal from the clutch mechanism disconnection detecting means. 
   According to a second aspect of the present invention, the clutch mechanism disconnection detecting means comprises motor current detecting means for detecting a motor current in the motor. When it is determined that a motor current detection signal from the motor current detecting means matches a predetermined value, the motor control device stops driving of the motor. 
   According to a third aspect of the present invention, the clutch mechanism can move between a connected position for connecting the power transmission path and a disconnected position for disconnecting the power transmission path, and includes a clutch gear for engaging a gear connected to the motor. The clutch gear includes clutch gear stopping/holding means for stopping rotation of the clutch gear when the clutch gear is located at the disconnected position. 
   According to a fourth aspect of the present invention, the clutch gear stopping/holding means is formed of teeth for engaging the clutch gear. 
   According to a fifth aspect of the present invention, the clutch mechanism can move between a connected position for connecting the power transmission path and a disconnected position for disconnecting the power transmission path, and includes a clutch gear for engaging a gear connected to the motor and resistance applying means for applying resistance to rotation of the clutch gear when the clutch gear is located at the disconnected position. 
   According to a sixth aspect of the present invention, a seatbelt device is provided with the seatbelt retractor in the first aspect of the invention. 
   In the seatbelt retractor according to one of the first to fifth aspects, when the clutch mechanism is disconnected, the motor control device stops the motor, thereby minimizing a period of time for driving the motor after the clutch mechanism is disconnected. Accordingly, the power consumption of the motor is effectively reduced. 
   In the seatbelt retractor according to one of the second to fifth aspects, when the clutch mechanism is disconnected and the motor current becomes a predetermined value, the motor control device stops the motor, thereby reducing power consumption of the motor in a surer manner. 
   In the seatbelt retractor according to one of the third and fourth aspects, when the clutch gear is located at the clutch disengaged position, the clutch gear stopping/holding means prohibits rotation of the clutch gear, thereby increasing the motor current relatively rapidly. Accordingly, it is possible to rapidly detect disconnection of the clutch mechanism in a sure manner, thereby effectively reducing power consumption of the motor and noise generated due to rotation of the clutch gear. In particular, in the seatbelt retractor according to the fourth aspect, the clutch gear stopping/holding means is formed of teeth engaging the clutch gear, thereby prohibiting rotation of the clutch gear when the clutch mechanism is disconnected and reducing power consumption of the motor and noise with a simple structure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view showing a seatbelt retractor according to an embodiment of the present invention; 
       FIG. 2  is a left side view of the seatbelt retractor shown in  FIG. 1  without a retainer cover; 
       FIGS. 3(   a ) and  3 ( b ) are views showing a sun gear member in the seatbelt retractor shown in  FIG. 1 , wherein  FIG. 3(   a ) is a perspective view thereof, and  FIG. 3(   b ) is a perspective view as viewed from a direction  3 ( b ) in  FIG. 3(   a ); 
       FIG. 4  is a left side view of the seatbelt retractor shown in  FIG. 1  with a part of components removed in a power transmission disconnected mode; 
       FIG. 5  is a left side view of the seatbelt retractor shown in  FIG. 1  with a part of the components removed in a low reduction ratio power transmission mode; 
       FIG. 6  is a left side view of the seatbelt retractor shown in  FIG. 1  with a part of the components removed in a high reduction ratio power transmission mode; 
       FIG. 7  is a view showing a seatbelt device provided with the seatbelt retractor shown in  FIG. 1 ; 
       FIG. 8  is a chart showing a change in a motor current; 
       FIG. 9  is a diagram showing another embodiment of the present invention corresponding to  FIG. 4 ; and 
       FIG. 10  is a view showing a seat belt device provided with the seat belt retractor shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings.  FIG. 1  is an exploded perspective view showing a seatbelt retractor according to an embodiment of the present invention.  FIG. 2  is a left side view of the seatbelt retractor shown in  FIG. 1  without a retainer cover. Note that “left” and “right” will represent the left and right sides in the drawings, respectively, unless noted otherwise. Furthermore, “clockwise” and “counterclockwise” represent the clockwise and counterclockwise directions in the drawings, respectively. 
   As shown in  FIG. 1 , a seatbelt retractor  1  according to the present embodiment primarily comprises a frame  2 ; a seatbelt  3  for restraining the passenger when necessary; a spool  4  for winding the seatbelt  3  thereon; lock means  5  disposed on one side of the frame  2  for prohibiting rotation of the spool  4  in the belt-extracting direction α upon large deceleration greater than a predetermined level in a collision or the like; a motor  6  for generating rotational torque applied to the spool  4 ; a power transmission gear mechanism  8  having a first power transmission path and a second power transmission path for transmitting the rotational torque of the motor  6  to the spool  4  through one of the first power transmission path and the second power transmission path, and having a high reduction ratio reducing mechanism  7   a  for reducing rotation of the motor  6  with a relatively high reduction ratio to transmit the reduced rotation to the spool  4  and a low reduction ratio reducing mechanism  7   b  for reducing rotation of the motor  6  with a relatively low reduction ratio to transmit the reduced rotation to the spool  4 ; and a power transmission mode switching mechanism  9  for switching between the first power transmission path and the second power transmission path of the power transmission gear mechanism  8 . 
   The frame  2  is formed of a pair of side walls  2   a  and  2   b  in parallel to each other and a back plate  2   c  connecting the side walls  2   a  and  2   b . The spool  4  is rotatably disposed between the side walls  2   a  and  2   b  within the flame  2  for winding the seatbelt  3  thereon. A conventionally-known and widely-used spool may be employed as the spool  4  of the seatbelt retractor  1 . The lock means  5  is attached to the side wall  2   a . A conventionally-known and widely-used lock means may be employed as the lock means  5 . When a vehicle sensor (deceleration sensor) detects large deceleration greater than a predetermined level applied to the vehicle, or a webbing sensor (belt retracting speed sensor) detects retraction of the seatbelt  3  at a predetermined speed, the lock means  5  prevents the spool  4  from rotating in the belt-extracting direction α. 
   A conventionally-known and widely-used force-limiting mechanism (not shown, energy absorbing mechanism referred to as “EA mechanism” hereafter) is provided between the spool  4  and the lock means  5  for limiting the load of the seatbelt  3  when the lock means  5  prevents the seatbelt  3  from unwinding. The EA mechanism may be formed of a conventionally-known torsion bar, so that when the lock means  5  prevents the seatbelt  3  from unwinding, the torsion bar is deformed to limit the load of the seatbelt  3 , thereby absorbing impact energy. 
   As shown in  FIGS. 1 and 2 , the motor  6  is secured on a surface of the retainer  11  with a pair of screws  12  where the side wall  2   b  of the frame  2  is secured with three screws  10 . A motor rotating shaft  6   a  of the motor  6  passes through a through hole  11   a . A motor gear  13  having outer teeth is integrally and rotatably secured to the motor rotating shaft  6   a  protruding from the surface of the retainer  11  opposite to the surface for mounting the frame  2 . 
   As shown in  FIG. 1 , a connector  14  is provided between the spool  4  with the EA mechanism (e.g., a torsion bar) and the reducing mechanisms  7   a  and  7   b  for connecting the same in the rotational direction. The connector  14  comprises a first rotary connecting portion  14   a  for connecting the spool  4  and the EA mechanism in the rotational direction; a second rotary connecting portion  14   b  for connecting a bearing  15  in the rotational direction, and a third rotary connecting portion  14   c  for connecting the reducing mechanism  7   a  and  7   b  formed in a spline shape in the rotational direction. 
   The first rotary connecting portion  14   a  is formed of a tube with a polygon shape (not clearly shown in  FIG. 1 ). The first rotary connecting portion  14   a  is integrally and rotatably connected to the spool  4  through an outer surface thereof, and is integrally and rotatably connected to the EA mechanism (e.g., a torsion bar) through an inner surface thereof. Note that the connecting mechanisms for integrally and rotatably connecting the spool  4  and the EA mechanism, and the connector  14 , are well known, and detailed description thereof are omitted. 
   The second rotary connecting portion  14   b  has an outer surface having a polygon cross section, and the connector bearing  15  has an inner surface having the same cross-section. The connector bearing  15  is fitted to the second rotary connecting portion  14   b  so as not to rotate relatively to each other. The connector bearing  15  is rotatably supported on a retainer bearing  16 . The retainer bearing  16   b  is mounted to the retainer  11  with an opening  11   b  so as not to rotate relatively to each other, whereby the connector  14  is rotatably supported on the retainer  11 . 
   The third rotary connecting portion  14   c  has engaging grooves such as spline grooves or the like extending in the axial direction thereof and formed at a predetermined pitch along the circumference direction thereof. 
   The high reduction ratio reducing mechanism  7   a  includes a circular carrier gear  17 , a predetermined number of planetary gears  18  rotatably mounted on the carrier gear  17  (three planetary gears in the drawings), a ring-shaped ring member  19 , and a sun gear member  20 . 
   The carrier gear  17  has a predetermined number of engaging grooves such as spline grooves or the like on the inner surface  17   a  for engaging the connector  14 , extending in the axial direction thereof and formed at a predetermined pitch. The predetermined number of engaging grooves formed on the inner surface  17   a  engage protrusions formed between the engaging grooves on the third rotary connecting portion  14   c  of the connector  14 , and protrusions formed between the engaging grooves on the inner surface  17   a  engaging the engaging grooves on the third rotary connecting portion  14   c  (engaging in the same way as with “spline engaging”), thereby connecting the carrier gear  17  and the connector  14  so as not to rotate relatively to each other, i.e., so as to rotate integrally. Furthermore, outer teeth  17   b  are formed on the outer surface of the carrier gear  17 . 
   The planetary gears  18  are rotatably mounted on the carrier gear  17  with reduction pins  22  through a reduction plate  21 . The ring member  19  includes an internal gear  19   a  formed on the inner surface thereof and a ratchet wheel  19   b  formed on the outer surface thereof, so that the internal gear  19   a  and the ratchet wheel  19   b  rotate together. 
   As shown in  FIG. 3(   a ) and  FIG. 3(   b ), the sun gear member  20  comprises a sun gear  20   a  formed of small-sized outer teeth and large-sized outer teeth  20   b , so that the sun gear  20   a  and the outer teeth  20   b  rotate integrally. Each planetary gear  18  supported by the carrier gear  17  engages the sun gear  20   a  and the internal gear  19   a  all the time, thereby constituting a planetary gear mechanism. Accordingly, the reducing mechanism  7  constitutes a planetary gear reducing mechanism, in which the sun gear  20   a  is an input end and the carrier gear  17  is an output end. 
   As shown in  FIG. 1 , the power transmission mechanism  8  further includes a connecting gear  23 ; a pair of clutch springs  24 ; a pair of pulleys  25 ; a lower connecting gear  26  having outer teeth; an upper connecting gear  27  having outer teeth; a guide plate  28 ; and an idling gear  29  having outer teeth. The connecting gear  23  is rotatably supported with a rotating shaft  11   c  formed on the retainer  11 , and includes a first connecting gear  23   a  formed of a large-diameter outer teeth and a small-diameter second connecting gear  23   b , so that the first and second connecting gears  23   a  and  23   b  are rotated integrally. In this case, the large-diameter first connecting gear  23   a  engages the motor gear  13  all the time as shown in  FIG. 2 . 
   As shown in  FIG. 1 , rotating shafts  26   a  protrude from side surfaces of the lower connecting gear  26  (only one rotating shaft  26   a  shown in  FIG. 1 ), and have a through hole  26   b  for inserting the rotating shafts  26   a  in the axial direction. Each rotating shaft  26   a  has a flat portion for fitting to a slot  25   a  of each pulley  25 . Thus, the pulleys  25  are rotatably supported on the side surfaces of the lower connecting gear  26  so as to rotate integrally with the lower connecting gear  26 . Each of the pulleys  25  engages the clutch spring  24  with a first curved connecting portion  24   a . Furthermore, the upper connecting gear  27  is supported on one of the rotating shafts  26   a  of the lower connecting gear  26  so as to rotate integrally with the lower connecting gear  26 . Furthermore, the pulleys  25 , the lower connecting gear  26 , and the upper connecting gear  27  are rotatably supported with a rotating shaft  11   d  protruding from the retainer  11 . 
   The guide plate  28  is mounted to the retainer  11  in a state that a pair of openings  28   a  formed on the guide plate  28  is fitted into a pair of supporting shafts  11   e  protruding from the retainer  11  by inserting a pair of screws  30  into the corresponding openings  28   a  of the guide plate  28  and screwing a pair of screws  30  into a pair of screw holes  11   f  formed in the retainer  11 . The idling gear  29  is rotatably supported by a rotating shaft  28   c  protruding from the guide plate  28 . As shown in  FIG. 2 , the idling gear  29  engages the outer teeth  20   b  of the sun gear member  20 , the small-sized second connecting gear  23   b  of the connecting gear  23 , and the upper connecting gear  27  all the time. 
   The low reduction ratio reducing mechanism  7   b  comprises the upper connecting gear  27 ; the lower connecting gear  26 ; a clutch gear  31 ; and the carrier gear  17 . Accordingly, the rotational torque of the motor  6  transmitted to the idling gear  29  is transmitted to the spool  4  through the low reduction ratio reducing mechanism  7   b  or the high reduction ratio reducing mechanism  7   a.    
   As shown in  FIG. 1 , the power transmission mode switching mechanism  9  comprises the clutch gear  31  having outer teeth; a rotating shaft  32 ; a clutch arm  33 ; a clutch pawl  34 ; a resistance spring  35 ; and a spring stopper  36 . As shown in  FIG. 5 , the clutch gear  31  engages the outer teeth  17   b  of the carrier gear  17  having a diameter greater than that of the clutch gear  31  and a lower connecting gear  26  (not shown, corresponding to a motor gear according to the present invention) all the time. A rotating shaft  32  passes through a center opening  31   a  so as to rotatably support the clutch gear  31 . 
   The clutch arm  33  is formed of a pair of side walls  33   a  and  33   b  and a bottom wall (not shown), and has a U-shape cross-section. The side walls  33   a  and  33   b  have protruding bottom ends, and a straight supporting groove  33   c  is formed at the bottom ends. The clutch gear  31  is disposed between the bottom ends of the side walls  33   a  and  33   b , and the rotating shaft  32  protruding from both side surfaces of the clutch gear  31  is supported by the supporting groove  33   c  to move along the supporting groove  33   c . A pair of clutch springs  24  is connected to the protrusions protruding from the side walls  33   a  and  33   b  of the rotating shaft  32  at second curved connecting portions  24   b  thereof. Furthermore, an end of the rotating shaft  32  is fitted to a guide opening  11   g  formed in the retainer  11 . The guide opening  11   g  is formed in an arc shape with the rotating shaft  11   d  as the center. Thus, the rotating shaft  32  is guided on the guide opening  11   g  so as to move along an arc with the rotating shaft  11   d  as the center. 
   The other ends of the side walls  33   a  and  33   b  include slots  33   d  and connecting portions  33   e  having an arc shape. Each of the middle portions of the side walls  33   a  and  33   b  in the longitudinal direction include a supporting opening  33   f . The clutch arm  33  is rotatably supported on the retainer  11  by fitting a supporting shaft  11   h  protruding from the retainer  11  to the supporting openings  33   f  formed in the side walls  33   a  and  33   b , and is fixed so as to not to come off by fixing an E ring  37  to the supporting shaft  11   h.    
   The clutch pawl  34  includes a supporting opening  34   a  at one end thereof, and the other end serves as a connecting pawl  34   b . Furthermore, the other end of the clutch pawl  34 , i.e., the connecting pawl  34   b , includes a connecting pin  34   c  erected thereon. The connecting pin  34   c  is fit to the slots  33   d  of the clutch arm  33  to move relatively to the clutch arm along the slots  33   d . As shown in  FIG. 4 , a pawl pin  38  passes through the supporting opening  34   a , and is inserted into and connected with a pin hole  11   i  formed in the retainer  11 , so that the clutch pawl  34  is rotatably mounted to the retainer  11 . As shown in  FIG. 6 , the connecting pawl  34   b  engages a ratchet wheel  19   b  so as to prohibit rotation of the ring member  19  in the clockwise direction (corresponding to the belt-extracting direction α of the spool  4 ), so that when the connecting pawl  34   b  engages the ratchet wheel  19   b , rotation of the ring member  19  in the clockwise direction is prohibited. 
   The resistance spring  35  is formed of a belt-shaped plate spring, and has a lower end formed in an L-shape as a supporting portion  35   a  and a recess  35   b  formed in a U shape at a middle-upper portion in the longitudinal direction. A portion between the recess  35   b  and the supporting portion  35   a  is formed in a flat shape, and a portion between the recess  35   b  and the upper end is formed in a curved shape. The recess  35   b  is formed so as to engage the connecting portion  33   e  of the clutch arm  33 . As shown in  FIG. 4 , in a state that the connecting portion  33   e  engages the recess  35   b , the supporting groove  33   c  extends in a direction same as the tangential direction of an arc of the guide opening  11   g , so that the rotating shaft  32  moves in direction from the guide opening  11   g  to the supporting groove  33   c  or from the supporting groove  33   c  to the guide opening  11   g.    
   The clutch mechanism according to the present invention comprises the clutch springs  24 , the pulleys  25 , the lower connecting gear  26 , the upper connecting gear  27 , the idling gear  29 , the clutch gear  31 , the rotating shaft  32 , the clutch arm  33 , the clutch pawl  34 , and the resistance spring  35 . The spring stopper  36  is formed in an L-shape, and the supporting portion  35   a  is held between the spring stopper  36  and a spring mounting portion  11   j  formed on the retainer  11 , so that the resistance spring  35  is mounted on the retainer  11  with the upper end as a free end and the lower end as a fixed end. 
   As shown in  FIGS. 1 ,  4 , and  6 , the retainer  11  includes a clutch gear stopping/holding portion  11   k  formed of inner teeth (corresponding to noise preventing means and clutch gear stopping and holding means). In the power transmission disconnected mode as shown in  FIG. 4 , wherein the rotating shaft  32  contacts the right end of the guide opening  11   g  so that the clutch gear  31  is positioned at the most-right position, the clutch gear  31  engages the inner teeth of the clutch gear stopping/holding portion  11   k  so as to stop rotation of the clutch gear  31  in the counterclockwise direction, and maintain the stopped state. 
   The components, i.e. the reducing mechanism  7 , power transmission gear mechanism  8 , and power transmission mode switching mechanism  9 , are mounted within recesses formed in the face of the retainer  11  opposite to the face for mounting the frame  2 , and a retainer cover  39  is mounted with a predetermined number (four in the drawings) of screws  40  to cover the components. 
   The power transmission gear mechanism  8  has the following three power transmission modes. 
   (1) Power Transmission Disconnected Mode 
   As shown in  FIG. 4 , in the power transmission disconnected mode, the connecting portion  33   e  of the clutch arm  33  forming the power transmission mode switching mechanism  9  engages the recess  35   b  of the resistance spring  35 . In the state wherein the connecting portion  33   e  engages the recess  35   b , the connecting pawl  34   b  of the clutch pawl  34  does not engage the ratchet wheel  19   b  of the ring member  19  so as to allow rotation of the ring member  19 . Accordingly, the torque transmission path (low speed and high torque transmission path described later) between the sun gear member  20  and the carrier gear  17  is disconnected. 
   On the other hand, the rotating shaft  32  contacts the right end of the guide opening  11   g  so as to position the clutch gear  31  at the most-right position, i.e. a power off position (clutch off position). The clutch gear  31  positioned at the power off position engages the inner teeth of the clutch gear stopping/holding portion  11   k  and is away from the outer teeth  17   b  of the carrier gear  17 , so that the clutch gear  31  does not rotate in the counterclockwise direction. Accordingly, the torque transmission path between the clutch gear  31  and the carrier gear  17  (high-speed and low-torque transmission path) is disconnected. As a result, in the power transmission disconnected mode, the spool  4  and the motor  6  are not connected so that the rotational torque of the motor  6  is not transmitted to the spool  4 , and the rotational torque of the spool  4  is not transmitted to the motor  6 . 
   (2) Low Reduction Ratio Power Transmission Mode 
   As shown in  FIG. 5 , in the low reduction ratio power transmission mode, the connecting portion  33   e  of the clutch arm  33  engages the recess  35   b  of the resistance spring  35  in the same way as in the power transmission disconnected mode. In the state wherein the connecting portion  33   e  engages the recess  35   b , the connecting pawl  34   b  of the clutch pawl  34  does not engages the ratchet wheel  19   b  of the ring member  19  so as to allow rotation of the ring member  19 . Accordingly, the low speed and high torque transmission path between the sun gear member  20  and the carrier gear  17  is disconnected. 
   On the other hand, the rotating shaft  32  is positioned at the uppermost position (closest to the rotating shaft of the spool  4 ) at the middle portion of the guide opening  11   g  so as to position the clutch gear  31  at the uppermost position (closest to the rotating shaft of the spool  4 ). The clutch gear  31  at the uppermost position engages the outer teeth  17   b  of the carrier gear  17 . Accordingly, the clutch gear  31  is positioned at the connected position wherein the high-speed and low-torque transmission path between the clutch gear  31  and the carrier gear  17  is connected. That is, the motor  6  is connected to the spool  4  through the motor gear  13 , the connecting gear  23 , the idling gear  29 , the upper connecting gear  27 , the lower connecting gear  26 , the clutch gear  31 , the carrier gear  17 , and the connector  14 . Accordingly, the low reduction ratio power transmission path is selected. The rotating shaft  32  at the uppermost position is inserted into the supporting groove  33   c  of the clutch arm  33  so as to contact the clutch arm  33 . 
   As described above, in the low reduction ratio power transmission mode, the high-speed and low-torque transmission path is selected. In the low reduction ratio power transmission-mode, it is possible to quickly retract the seatbelt with the motor  6 . 
   (3) High Reduction Ratio Power Transmission Mode 
   As shown in  FIG. 6 , in the high reduction ratio power transmission mode, the connecting portion  33   e  of the clutch arm  33  separates from the recess  35   b  of the resistance spring  35 , and is positioned at the curve portion of the resistance spring  35  at an upper position of the recess  35   b . In the state wherein the connecting portion  33   e  separates from the recess  35   b , the connecting pawl  34   b  of the clutch pawl  34  engages the ratchet wheel  19   b  of the ring member  19  so as to prohibit rotation of the ring member  19  in the clockwise direction. That is, the low speed and high torque transmission path between the sun gear member  20  and the carrier gear  17  is connected. Accordingly, the motor  6  is connected to the spool  4  through the motor gear  13 , the connecting gear  23 , the idling gear  29 , the outer teeth  20   b  of the sun gear member  20 , the sun gear  20   a , the planetary gears  18 , the carrier gear  17 , and the connector  14 . As a result, the high reduction ratio power transmission path by the planetary gear mechanism is selected. 
   On the other had, the rotating shaft  32  contacts the left end of the guide opening  11   g  so as to position the clutch gear  31  at the most left position. The clutch gear  31  at the most left position separates from the outer teeth  17   b  of the carrier gear  17 . Accordingly, the high speed and low torque transmission path between the clutch gear  31  and the carrier gear  17  is disconnected. In the high reduction ratio power transmission mode, the low speed and high torque transmission path is selected. In the high reduction ratio power transmission mode, the seatbelt is retracted with a high tension by the motor  6 . 
   As described above, the clutch gear  31  can move between the connected position for connecting the power transmission path and the disconnected position for disconnecting the power transmission path. The power transmission mode switching mechanism  9  selects the power transmission mode from one of the power transmission disconnected mode, the low reduction ratio power transmission mode, and the high reduction ratio power transmission mode. 
   (1) Switching from the Power Transmission Disconnected Mode to the Low Reduction Ratio Power Transmission Mode 
   In the power transmission disconnected mode shown in  FIG. 4 , when the motor  6  rotates forward (rotation of the motor rotating shaft  6   a  in the clockwise direction in  FIG. 4  corresponding to rotation of the spool  4  in the belt-retracting direction α), the lower clutch gear  26  and the pulleys  25  are rotated in the direction corresponding to the belt-retracting direction α of the spool  4  through the motor gear  13 , the connecting gear  23 , the idling gear  29 , and the upper clutch gear  27 . In this case, while the clutch gear  31  rotates in the direction corresponding to the belt-retracting direction α, i.e. the clockwise direction in  FIG. 4 , the clutch gear  31  engages the inner teeth of the clutch gear stopping/holding portion  11   k , and the rotating shaft  32  is free from any resistance. Accordingly, the clutch springs  24  turn in the same direction as the pulleys  25 . Accordingly, the clutch gear  31  and the rotating shaft  32  move in the left direction along the guide opening  11   g.    
   When the clutch gear  31  and the rotating shaft  32  move toward the left side by a predetermined distance, the clutch gear  31  separates from the inner teeth of the clutch gear stopping/holding portion  11   k  so as to enable rotation without any load, and then the rotating shaft  32  contacts the clutch arm  33  as shown in  FIG. 5 . 
   In the state wherein the rotating shaft  32  contacts the clutch arm  33 , the clutch gear  31  and the rotating shaft  32  are positioned at the uppermost positions as shown in  FIG. 5 , and the clutch gear  31  engages the outer teeth  17   b  of the carrier gear  17 . Accordingly, rotation of the clutch gear  31  is transmitted to the carrier gear  17 , whereby the carrier gear  17  is rotated. In this case, if the seatbelt  3  has slack, the seatbelt  3  is wound onto the spool  4  by rotation of the carrier gear  17 . When the seatbelt is wound, the spool  4  does not rotate and the carrier gear  17  does not rotate. Accordingly, the clutch gear  31  does not rotate due to resistance applied from the carrier gear  17 . 
   On the other hand, the lower connecting gear  26  is forced to rotate due to rotational torque of the motor  6 , and accordingly, force is applied to the rotating shaft  32  so as to move toward the most left position due to rotational torque of the lower connecting gear  26 . In this case, the rotating shaft  32  contacts the clutch arm  33 , and accordingly, the clutch arm  33  is pressed by the rotating shaft  32 . However, at this time, the seatbelt  3  is tightened with a force less than a predetermined tension. Accordingly, the momentum for rotating the clutch arm  33  in the clockwise direction due to pressing force applied from the rotating shaft  32  is smaller than the momentum for preventing rotation of the clutch arm  33  in the clockwise direction due to the connection between the connecting portion  33   e  and the recess  35   b . Accordingly, the connecting portion  33   e  does not separate from the recess  35   b , the clutch arm  33  is not turned, and the rotating shaft  32  is stopped at the position where the rotating shaft  32  contacts the clutch arm  33 . 
   As described above, the rotating shaft  32  is stopped, and accordingly, the clutch gear  31  and the rotating shaft  32  are held at the uppermost positions as shown in  FIG. 5 . The clutch gear  31  is held at the uppermost position, thereby maintaining the engagement between the clutch gear  31  and the outer teeth  17   b  of the carrier gear  17 , and connection of the high speed and low torque transmission path between the clutch gear  31  and the carrier gear  17 . Furthermore, the clutch arm  33  is not turned, and accordingly, the clutch pawl  34  is not turned, thereby holding the connecting pawl  34   b  at a position where the connecting pawl  34   b  does not engage the ratchet wheel  19   b . As a result, the ring member  19  rotates freely and maintains the disconnection of the low speed and high torque transmission path between the sun gear member  20  and the carrier gear  17 . Accordingly, the power transmission mode of the power transmission mechanism  8  is switched from the power transmission disconnected mode to the low reduction ratio power transmission mode, whereby the power transmission mechanism  8  becomes the low reduction ratio power transmission mode. 
   (2) Switching from the Low Reduction Ratio Power Transmission Mode to the High Reduction Ratio Power Transmission Mode 
   The high reduction ratio power transmission mode is set by relatively high rotational torque of the motor  6 . In this case, the power transmission mode is switched from the power transmission disconnected mode to the high reduction ratio power transmission mode through the low reduction ratio power transmission mode. Switching of the power transmission mode from the power transmission disconnected mode to the low reduction ratio power transmission mode is performed in the same way as described above. However, at the time of setting the power transmission mode to the high reduction ratio power transmission mode, the tension of the seatbelt  3  is greater than a predetermined value. Accordingly, the momentum applied to the clutch arm  33  due to the pressing force from the rotating shaft  32  is greater than the momentum for preventing rotation of the clutch arm  33  in the clockwise direction due to connection of the connecting portion  33   e  with the recess  35   b . As a result, the connecting portion  33   e  separates from the recess  35   b.    
   When the clutch springs  24  rotate further in the counterclockwise direction, the rotating shaft  32  moves toward the left side along the guide opening  11   g  while the clutch arm  33  rotates around the supporting shaft  11   h  in the clockwise direction. Accordingly, the clutch gear  31  further moves in the left direction as well. When the rotating shaft  32  contacts the left end of the guide opening  11   g , the rotating shaft  32  does not move further, and the clutch gear  31 , the rotating shaft  32 , and the clutch springs  24  are stopped. Accordingly, as shown in  FIG. 6 , the clutch gear  31  and the rotating shaft  32  are positioned at the most left positions. The clutch gear  31  at the most left position separates from the outer teeth  17   b  of the carrier gear  17 , and accordingly, the high speed and low torque transmission path between the clutch gear  31  and the carrier gear  17  is disconnected. 
   On the other hand, the clutch pawl  34  rotates around the clutch pawl pin  38  in the counter clockwise direction along with the rotation of the clutch arm  33 , and the connecting pawl  34   b  is positioned at a position to engage the ratchet wheel  19   b  as shown in  FIG. 6 . In this case, the sun gear member  20  rotates by rotational torque of the motor  6 , and the ring member  19  rotates in the clockwise direction. Accordingly, the ratchet wheel  19   b  engages the connecting pawl  34   b , and the ring member  19  stops, so that the low speed and high torque transmission path between the sun gear member  20  and the carrier gear  17  is connected. 
   As described above, switching of the power transmission mode of the power transmission mechanism  8  is performed from the low reduction ratio power transmission mode to the high reduction ratio power transmission mode, whereby the power transmission mechanism  8  becomes the high reduction ratio power transmission mode. 
   (3) Switching from the High Reduction Ratio Power Transmission Mode to the Power Transmission Disconnected Mode through the Low Reduction Power Transmission Mode 
   In the high reduction ratio power transmission mode shown in  FIG. 6 , when the motor  6  rotates in the reverse direction (rotation of the motor rotating shaft  6   a  in the counterclockwise direction, corresponding to rotation of the spool  4  in the belt-extracting direction α), the lower connecting gear  26  and the pulleys  25  rotate in the reverse direction. Also, the clutch springs  24  rotate in the reverse direction. Accordingly, the clutch gear  31  and the rotating shaft  32  move in the right direction along the guide opening  11   g  while turning the clutch arm  33  in the counterclockwise direction. 
   At the same time, the clutch pawl  34  turns in the clockwise direction corresponding to turning of the clutch arm  33  in the counterclockwise direction. Accordingly, the clutch pawl  34  is positioned at the disconnected position where the clutch pawl  34  is not connected to the ratchet wheel  19   b . The ring member  19  rotates freely, and the low speed and high torque transmission path is disconnected. 
   When the clutch gear  31  and the rotating shaft  32  reach the uppermost positions, the clutch gear  31  engages the outer teeth  17   b  of the carrier gear  17 . Accordingly, the power transmission mechanism  8  temporarily becomes the low reduction ratio power transmission mode shown in  FIG. 5 . The clutch gear  31  immediately separates from the outer teeth  17   b  due to continuous movement of the clutch gear  31  and the rotating shaft  32  in the right direction, and the clutch gear  31  rotates freely. Accordingly the high speed and low torque transmission path is connected, and then immediately disconnected. When the high speed and low torque transmission path is connected temporarily, the motor  6  rotates in the reverse direction, and the spool  4  temporarily rotates in the belt-extracting direction α and stops. 
   The rotating shaft  32  moves from the uppermost position in the right direction and separates from the clutch arm  33 . The clutch gear  31  and the rotating shaft  32  further move in the right direction due to further turning of the clutch springs  24  in the reverse direction. Accordingly, the clutch gear  31  engages the inner teeth of the clutch gear stopping/holding portion  11   k . The rotating shaft  32  contacts the right end of the guide opening  11   g  and stops. Accordingly, the clutch gear  31 , the rotating shaft  32 , and the clutch springs  24  are stopped. The clutch gear  31  and the rotating shaft  32  are positioned at the power transmission disconnecting positions, i.e. the most right positions shown in  FIG. 4  described above. In this case, the clutch gear  31  engages the inner teeth of the clutch gear stopping/holding portion  11   k  and stops. 
   As described above, the power transmission mode of the power transmission mechanism  8  is switched from the high reduction ratio power transmission mode to the power transmission disconnected mode, whereby the power transmission mechanism  8  becomes the power transmission disconnected mode. An operation of stopping the motor  6  will be described later. 
   According to the present embodiment, the seatbelt retractor  1  has the following belt modes of the seatbelt  3 . The belt modes include a belt storage mode wherein the seatbelt  3  is not worn by the passenger and is completely wound onto the spool  4 ; a belt extracting mode wherein the seatbelt  3  is extracted from the spool  4  so as to be worn by the passenger; a fitting belt retracting mode wherein the seatbelt  3  is fit to the passenger in a situation where the passenger wear the seatbelt  3 ; a normal wearing mode (comfortable mode) wherein the passenger wears the seatbelt  3  in a normal situation without any pressure; a warning mode wherein in an event that the system detects dozing off of the driver or an obstacle in front of the vehicle in the direction of movement, the seatbelt  3  is retracted repeatedly predetermined times for warning the driver; an emergency mode wherein in an event that the vehicle extremely likely have a collision with an obstacle or the like while moving, the seatbelt  3  is retracted so as to restrain the passenger with an extremely strong belt tension; and a storing belt retracting mode wherein the seatbelt  3  is retracted so as to be completely wound onto the spool  4  when the passenger does not wear the seatbelt  3 . 
   In the seatbelt retractor  1  according to the present embodiment, when the clutch gear  31  is positioned at the disconnected position in the power transmission disconnected mode shown in  FIG. 4  from the low reduction ratio power transmission mode shown in  FIG. 5 , or the high reduction ratio power transmission mode shown in  FIG. 6 , the motor  6  automatically stops.  FIG. 7  is a circuit diagram for automatically stopping the motor  6  and controlling the motor  6  to set the belt modes described above. 
   As shown in  FIG. 7 , the motor  6  is connected to a power supply  41  through electric power supply switching means  42  and clutch mechanism disconnection detecting means  43 . The electric power supply switching means  42  controls electric power supply from the power supply  41  to the motor  6 , and is formed of a relay switch  42   a , for example. The clutch mechanism disconnection detecting means  43  detects a situation wherein the clutch gear  31  is positioned at the disconnected position and the clutch is completely disconnected, and is formed of a motor current detector (corresponding to motor current detecting means)  43   a  for detecting a motor current I(A) flowing in the motor  6 . 
   The motor  6 , electric power switching means  42 , and clutch mechanism disconnection detecting means  43  are connected to a motor control device (referred to as “CPU” hereafter)  44 . The CPU  44  controls on/off of the electric power supply switching means  42  and a rotational direction (forward or reverse) of the motor  6  corresponding to the selected belt mode when the belt mode is selected. In this case, the CPU  44  controls the motor  6  to automatically stop as described above according to a detected signal of the motor current I(A) detected by the motor current detector  43   a.    
   That is, the motor  6  rotates in the reverse direction so as to switch the power transmission mode from the low reduction ratio power transmission mode sown in  FIG. 5  to the power transmission disconnected mode shown in  FIG. 4 . In the low reduction ratio power transmission mode shown in  FIG. 5 , the clutch gear  31  engages the outer teeth  17   b  of the carrier gear  17 , so that the clutch gear  31  receives resistance while rotating. Accordingly, the motor current I (A) increases to a current I 1  (A) shown in  FIG. 8  due to the load of the motor  6  from the resistance of the clutch gear  31 . 
   When the clutch gear  31  rotates and separates from the outer teeth  17   b  of the carrier gear  17  while the clutch gear  31  and the rotating shaft  32  move from the position shown in  FIG. 5  in the right direction, the clutch gear rotates without any load, so that the load of the motor  6  decreases and the motor current I (A) decreases to a lower current I 2  (A) lower than the current I 1  (A) shown in  FIG. 8 . 
   When the clutch gear  31  reaches the disconnected position, the clutch gear  31  stops, so that the load of the motor  6  increases, and the motor current I (A) increases relatively rapidly as shown by a solid curve in  FIG. 8 . When the motor current I (A) reaches a predetermined current I 3  (A) (threshold value according to the present invention), the motor current detector  43   a  detects the predetermined current I 3  (A). The CPU  44  determines that the clutch gear  31  reaches the disconnected position according to the predetermined current I 3  (A) detected by the motor current detector  43   a , and the relay switch  42   a  is turned off. Accordingly, the power supply from the power supply  41  to the motor  6  is stopped to stop the motor  6 . 
   With the seatbelt retractor  1  having such a configuration, the power transmission mechanism  8  includes two power transmission paths, i.e. the high speed and low torque power transmission path serving as the low reduction ratio power transmission mode, and the low speed and high torque power transmission path serving as the high reduction ratio power transmission mode. Accordingly, the seatbelt retractor  1  has two functions, i.e. rapid belt retraction for winding the seatbelt  3  in the low reduction ratio power transmission mode, and high-torque belt retraction for restraining the passenger in the high reduction ratio power transmission mode. 
   According to the present embodiment, the rotational torque of the motor  6  is efficiently transmitted to the spool  4  through selecting the two power transmission paths, thereby performing the two modes of retracting the seatbelt in a sure manner with small power consumption. In particular, with the seatbelt retractor  1  according to the present embodiment, high-torque seatbelt retraction is performed for restraining the passenger through the low speed and high torque power transmission path, so that the motor  6  is driven with small rotational torque as compared with the conventional one. Thus, a small-sized motor is employed as the motor  6 , as well as driving the motor with reduced power consumption, thereby reducing the size of the seatbelt retractor  1 . 
   Furthermore, with the seatbelt retractor  1  according to the present embodiment, the power transmission mechanism  8  becomes the power transmission mode selected from the low reduction ratio power transmission mode and the high reduction ratio power transmission mode according to the tension of the seatbelt  3 , thereby easily performing mode switching without controlling rotational torque of the motor  6 . The power transmission mechanism  8  has the power transmission disconnected mode wherein rotational torque of the motor  6  is not transmitted to the spool  4 . Accordingly, extraction of the seatbelt  3 , normal wearing of the seatbelt  3  without any pressure, and storage of the seatbelt  3  are performed without an influence of the motor  6 . 
   Furthermore, the high reduction ratio reducing mechanism  7   a  is formed of a planetary gear mechanism, thereby reducing the size of the low speed and high torque transmission path. The size of the seatbelt retractor  1  including both the low reduction ratio power transmission mode and the high reduction ratio power transmission mode is also reduced. 
   Furthermore, the carriers of the high reduction ratio reducing mechanism  7   a  and the outer teeth  17   b  of the low reduction ratio reducing mechanism  7   b  form a single carrier gear  17 , thereby reducing the size of the seatbelt retractor  1  and the number of the components thereof. The power transmission mode switching mechanism  9  controls the internal gear  19   a  of the planetary gear mechanism to rotate and controls the small-diameter clutch gear  31  to engage the outer teeth  17   b  of the large-diameter carrier gear  17  according to a tension of the seatbelt  3 , thereby easily switching the power transmission mode. 
   Furthermore, when the clutch gear  31  is positioned at the disconnected position, the clutch gear  31  engages the inner teeth of the clutch gear stopping/holding portion  11   k , the clutch gear  31  is stopped, thereby increasing the load of the motor  6 . Accordingly, the motor current I (A) increases, thereby detecting the disconnected position of the clutch gear  31 , i.e. complete disconnection of the clutch, in a sure manner. Thus, it is possible to minimize the period of time for rotating the motor  6  in the reverse direction after the clutch is disconnected, thereby effectively reducing power consumption of the motor  6 . The clutch gear  31  is stopped at the disconnected position, thereby reducing noise due to rotation of the clutch gear  31  and other gears in a sure manner. 
     FIG. 9  shows a seatbelt retractor according to another embodiment of the present invention corresponding to  FIG. 4 . In the embodiment described above, the clutch gear stopping/holding portion  11   k  formed of the inner teeth is provided on the retainer  11 . In the seatbelt retractor  1  according to the present embodiment, the clutch gear stopping/holding portion  11   k  is omitted as shown in  FIG. 9 . 
   In the seatbelt retractor  1  having such a configuration, when the motor  6  rotates in the reverse direction to switch the power transmission mode from the low reduction ratio power transmission mode shown in  FIG. 5  to the power transmission disconnected mode shown in  FIG. 4 , the motor current I (A) changes from the current I 1  (A) to the current I 2  (A). 
   When the clutch gear  31  reaches the disconnected position, the rotating shaft  32  stops moving in the right direction and the clutch springs  24  stops rotating in the clockwise direction as shown in  FIG. 9 . While the clutch gear  31  continues free rotation, the clutch springs  24  engage the rotating shaft  32  due to friction. Accordingly, the clutch gear  31  receives resistance due to the rotating of the clutch springs  24  stopping, thereby increasing the load of the motor  6  (clutch springs  24  forming resistance applying means according to the present invention). 
   Accordingly, as shown in  FIG. 8 , the motor current I (A) temporarily decreases from the current I 1  (A) to the current I 2  (A) in the same way as described above. Then, the motor current I (A) increases at a rate relatively lower than before as indicated by a hidden line, and reaches a current I 4  (A) greater than the current I 1  (A). The motor current detector  43   a  detects the current I 4  (A) corresponding to the threshold value according to the present invention. The CPU  44  determines that the clutch gear  31  reaches the disconnected position according to the current I 4  (A) detected by the motor current detector  43   a , and the relay switch  42   a  is turned off. Accordingly the power supply from the power supply  41  to the motor  6  is stopped to stop the motor  6 . 
   The seatbelt retractor  1  according to the present embodiment does not include the clutch gear stopping/holding means  11   k  formed of the inner teeth unlike the embodiment described above, thereby making the structure simple. Note that the seatbelt retractor  1  according to the present embodiment has other configuration and advantages same as those of the embodiment described above. 
   In the present embodiment, the motor current I (A) is monitored to determine whether the clutch gear  31  reaches the disconnected position, and the present invention is not limited to the arrangement. Alternatively, other means such as contact-type detecting means such as a limit switch or the like, or non-contact type detecting means such as an optical sensor, magnetic sensor, or the like may be used. 
   The power transmission mode switching means is not limited to the power transmission mode switching mechanism  9  using high torque and low torque of the motor  6 . Alternatively, a mechanism such as a solenoid or the like may be used as the power transmission mode switching means. 
   Furthermore, the single carrier gear  17  does not need to be formed of the high reduction ratio reducing mechanism  7   a  and the low reduction ratio mechanism  7   b , and may be formed of other members. 
   Furthermore, the motor  6  has the constant rotational torque during switching of the power transmission mode. Alternatively, the rotational torque of the motor  6  is controlled according to the belt modes such as the fitting belt retracting mode, the warning mode, the emergency mode, the belt storage mode, and the like. 
   The seatbelt retractor according to the present invention is suitable for a vehicle such as an automobile or the like for retracting a seatbelt for restraining and protecting the passenger by a motor. 
     FIG. 10  is a view showing a seatbelt device provided with the seatbelt retractor  1  shown in  FIG. 1 . As shown in  FIG. 10 , a seatbelt device  45  includes the seatbelt retractor  1  fixed to a portion of a vehicle body such as a vehicle floor and the like; a belt guide  48  attached to a portion of the vehicle body such as a center pillar and the like for guiding a seatbelt  47  extending from the seatbelt retractor  1  into a predetermined position relative to an occupant; an anchor  49  fixed to a portion of the vehicle body such as a floor and the like on an outer side of a vehicle seat and to which an end of the seatbelt  47  is connected; a tongue  50  slidably supported to the seatbelt  47 ; a buckle  42  fixed to a portion of the vehicle body such as a floor and the like on an inner side of the vehicle seat and to which the tongue  50  can be latched; a buckle supporting member  41  for supporting the buckle  42 ; a connecting member  43  connecting the buckle supporting member  41  and the buckle  42 ; and a boot  44  disposed between the buckle  42  and the buckle supporting member  41 . 
   The disclosure explained in the specification and shown in the drawings in Japanese Patent Application No. 2003-355294 filed on Oct. 15, 2003 is hereby incorporated into the present application. 
   While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.