Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 USC 119 from Japanese Patent Application No. 2006-037125, the disclosure of which is incorporated by reference herein. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention pertains to a webbing winding apparatus, and particularly relates to a motor retractor which can wind up a webbing by rotating a winding shaft with a motor. 
         [0004]    2. Related Art 
         [0005]    A conventional motor retractor is structured so as to interrupt power feeding to the motor when a passenger&#39;s arm, or the like, catches the webbing during winding resulting in the motor being overloaded (referring to Japanese Patent Application Laid-Open No. 2004-244011). With this motor retractor, the power feeding to the motor is resumed after the lapse of a predetermined time following the interruption of the power feeding to the motor, and thus, the passenger can release their arm, or the like, from the webbing within the above-mentioned predetermined time, and with the power feeding to the motor being resumed, winding-up of the webbing can be completed. 
         [0006]    However, with such a motor retractor, if winding-up the webbing is resumed in a state in which the passenger has not released their arm, or the like, from the webbing, a sense of discomfort may be given to the passenger. Particularly, in a state in which most of the webbing has been wound up, the passenger&#39;s arm, or the like, will be easily pulled by the webbing, which can increase the sense of discomfort given to the passenger. 
       SUMMARY 
       [0007]    The present invention has been made in view of the above-mentioned situation, and the purpose thereof is to provide a motor retractor which, even when winding-up of the webbing is resumed in a state in which an arm, or the like, has not been released from being caught by the webbing, the sense of discomfort given to a passenger can be reduced. 
         [0008]    The motor retractor of a first aspect of the present invention provides a motor retractor, comprising: a winding shaft which winds up a webbing for restraining a vehicle passenger; a motor which rotates the winding shaft in a webbing winding-up direction; and a control portion which, after release of the webbing wearing state of the passenger: drives the motor to cause the webbing to be wound up around the winding shaft; stops the motor when an overload on the motor is detected during the winding-up; redrives the motor after a predetermined time having elapsed after the motor is stopped due to detection of the overland, and adjusts, at the time of the redriving, a driving state of the motor according to the time of driving the motor that has elapsed before the overload detection. 
         [0009]    In the motor retractor of the first aspect, when, in a state in which the webbing is being wound up around the winding shaft by the driving of the motor, the passenger&#39;s arm, or the like, for example, gets caught by the webbing, resulting in the motor being overloaded, the control portion detects the overload of the motor, and stops the motor, and redrives the motor after a predetermined time has elapsed. 
         [0010]    Herein, with this motor retractor, when the control portion redrives the motor as described above, the control portion adjusts the driving state of the motor according to the driving time of the motor that has elapsed before the above-mentioned overload is detected. That is, the above-mentioned driving time of the motor corresponds to the amount of the webbing wound up on the winding shaft at the time of the above-mentioned overload detection, and thus, even when the passenger has not released their arm, or the like, from the webbing  28  within the above-mentioned predetermined time, the control portion adjusts the driving state of the motor (that is, the driving force, the rotation speed, the driving time, and the like) at the time of the redrive according to the above-mentioned driving time of the motor, whereby the sense of discomfort given to the passenger can be reduced. The overload on the motor can be detected by, for example, detecting that the supply current to the motor has increased beyond a predetermined threshold value. 
         [0011]    The motor retractor of a second aspect of the present invention provides the motor retractor of the first aspect, wherein said control portion adjusts the driving state of the motor by changing the magnitude of a voltage applied to the motor 
         [0012]    In the motor retractor of the second aspect, the control portion controls the motor with voltage, and thus even when, for example, the motor is driven in a state in which the engine of the vehicle is stopped, resulting in the power supply voltage becoming unstable, the rotation speed of the motor, that is, the speed of winding-up the webbing, can be kept constant without being influenced by fluctuations of the power supply voltage. 
         [0013]    The motor retractor of a third aspect of the present invention provides the motor retractor of the first aspect or the second aspect, wherein, when the time of driving the motor that has elapsed before the overload detection is equal to or longer than a preset time, the control portion lowers the magnitude of a supply current to the motor at the time of the redriving. 
         [0014]    With the motor retractor of the third aspect, when the driving time of the motor that has elapsed before the overload detection is equal to or longer than the preset time, that is, when, for example, most of the webbing has been wound up on the winding shaft, the magnitude of the supply current to the motor at the time of the redrive of the motor is lowered. Thereby, the winding force and the winding-up speed of the webbing are lowered, and thus even when the motor is redriven in a state in which the passenger has not released their arm, or the like, from the webbing, the sense of discomfort given to the passenger can be reduced. 
         [0015]    The motor retractor of a fourth aspect of the present invention provides the motor retractor of any one of the first aspect to the third aspect, wherein, when the time of driving the motor that has elapsed before the overload detection is equal to or longer than a preset time, the control portion shortens a time of driving the motor at the time of the redriving. 
         [0016]    With the motor retractor of the fourth aspect, when the driving time of the motor that has elapsed before the overload detection is equal to or longer than the preset time, that is, when, for example, the amount of webbing to be wound up has become smaller, the driving time of the motor at the time of redriving the motor is shortened, and thus unnecessary driving of the motor after the winding-up of the webbing is completed, can be prevented, and accordingly the occurrence of noise due to the unnecessary driving, can be suppressed. 
         [0017]    The motor retractor of a fifth aspect of the present invention provides the motor retractor of any one of the first aspect to the fourth aspect, wherein, when a preset time has elapsed after the motor is driven for the first time following the release of the webbing wearing state, the control portion lowers the magnitude of a supply current to the motor. 
         [0018]    With the motor retractor of the fifth aspect, when the preset time has elapsed after the motor has been driven for the first time following the release of the webbing wearing state of the passenger, that is, when, for example, in a state in which most of the webbing has been wound up, and it becomes difficult for the passenger to release their arm, or the like, from the webbing, the magnitude of the supply current to the motor is lowered. Thereby, the webbing winding-up force and winding-up speed are lowered, and thus the passenger can release their arm, or the like, from the webbing easily. 
         [0019]    The motor retractor of a sixth aspect of the present invention provides a motor retractor, comprising: a winding shaft which winds up a webbing for restraining a vehicle passenger; a motor which rotates the winding shaft in a webbing winding-up direction; and a control portion which, after release of a webbing wearing state of the passenger: feeds power to the motor to cause the webbing to be wound up around the winding shaft; interrupts the power feeding to the motor when an overload on the motor is detected during the winding; and gradually increases the magnitude of a current to resume the power feeding to the motor after the interruption of power feeding to the motor. 
         [0020]    With the motor retractor of the sixth aspect, when, in a state in which the webbing is being wound up around the winding shaft by the power feeding to the motor, the passenger&#39;s arm, or the like, for example, gets caught by the webbing, resulting in the motor overload, the control portion detects the motor overload, interrupts the power feeding to the motor, and resumes the power feeding to the motor after a predetermined time has elapsed. 
         [0021]    Herein, in this motor retractor, when the control portion resumes the power feeding to the motor as described above, the control portion gradually increases the magnitude of the current to resume the power feeding to the motor. Therefore, even when, during the time the power feeding to the motor has been interrupted, resulting in the motor being stopped, the passenger has not released their arm, or the like, from the webbing, the rush current flowing to the motor at the time of the resumption of the power feeding can be reduced, and thus the rush current can be prevented from causing the motor to be rapidly driven, resulting in a sense of discomfort given to the passenger. The motor overload can be detected by, for example, detecting that the supply current to the motor has increased beyond a predetermined threshold value. 
         [0022]    The motor retractor of a seventh aspect of the present invention provides the motor retractor of the sixth aspect, wherein the control portion decreases the magnitude of a stationary current for the motor after the resumption of the power feeding to a value that is smaller than the magnitude of the stationary current for the motor before the overload detection. 
         [0023]    With the motor retractor of the seventh aspect, because the magnitude of the stationary current for the motor after the resumption of the power feeding is decreased to a value smaller than the magnitude of the stationary current for the motor before the overload detection, the driving force and the rotation speed of the motor, that is, the winding-up force and the winding-up speed for the webbing are also decreased. Therefore, the sense of discomfort given to the passenger can be further reduced. 
         [0024]    As described above, with the motor retractor according to the present invention, even when the winding-up of the webbing is resumed in a state in which a passenger&#39; arm, or the like, has not been released, the sense of discomfort given to the passenger can be reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a front sectional view schematically illustrating the overall configuration of a motor retractor according to a first embodiment of the present invention; 
           [0026]      FIG. 2A  is a timing chart illustrating the relationship between a current to be supplied to a motor by a control portion of a motor retractor according to the first embodiment of the present invention, and time; 
           [0027]      FIG. 2B  is a timing chart illustrating the relationship between the current to be supplied to the motor by the control portion of the motor retractor according to the first embodiment of the present invention, and time; 
           [0028]      FIG. 2C  is a timing chart illustrating the relationship between the current to be supplied to the motor by the control portion of the motor retractor according to the first embodiment of the present invention and the time; 
           [0029]      FIG. 2D  is a timing chart illustrating the relationship between the current to be supplied to the motor by the control portion of the motor retractor according to the first embodiment of the present invention, and time; and 
           [0030]      FIG. 3  is a timing chart illustrating the relationship between the current to be supplied to the motor by the control portion of a motor retractor according to a second embodiment of the present invention, and time. 
       
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       [0031]      FIG. 1  is a front sectional view illustrating the overall configuration of a motor retractor  10  according to a first embodiment of the present invention. 
         [0032]    As shown in  FIG. 1 , the motor retractor  10  comprises a frame  12 . The frame  12  comprises a substantially plate-like back plate  14 , and by fixing this back plate  14  to a vehicle body by means of a connecting part (not shown), such as a bolt, or the like, the present motor retractor  10  is mounted to the vehicle body. From both ends of the back plate  14  in a width direction, a pair of foot plates  16 ,  18  are extended in parallel with each other, and between these foot plates  16 ,  18 , a spool  20 , serving as a winding shaft and manufactured by die casting or the like, is rotatably disposed. 
         [0033]    The spool  20  is made up of a substantially cylindrical spool main body  22 , and a pair of flange portions  24 ,  26  formed substantially in the shape of a disk at both ends of this spool main body  22 , and as a whole, has the shape of a drum. 
         [0034]    To the spool main body  22 , the base end portion of a webbing  28  formed in the shape of a long strip is connected and fixed, and when the spool  20  is rotated in one direction around the axis thereof (hereinafter, this direction is called the “winding-up direction”), the webbing  28  is wound up from the base end side thereof around the circumference of the spool main body  22  in layers. On the other hand, when the webbing  28  is taken out from the tip end thereof, the spool  20  is rotated while the webbing  28  is taken out (hereinafter, the direction of rotation of the spool  20  when the webbing  28  is taken out is called the “taking-out direction”). 
         [0035]    On the side of the flange part  24  that is opposite to the flange part  26 , one end side of the spool  20  penetrates substantially coaxially into a round hole  30  formed in the foot plate  16  to protrude to the outside of the frame  12 . On the outside of the frame  12  at the foot plate  16  side, a casing  32  is disposed. The casing  32  is disposed along the axial direction of the spool  20 , facing the foot plate  16 , and fixed to the foot plate  16 . In addition, the casing  32  is opened as a whole toward the foot plate  16  side, and the one end side of the spool  20  penetrating into the round hole  30  enters into the casing  32 , and is rotatably pivotally-supported by the casing  32 . 
         [0036]    Further, inside of the casing  32 , a spiral spring  34  is disposed. The outside end in the spiral direction of the spiral spring  34  is engaged at the casing  32 , while the inside end in the spiral direction of the spiral spring  34  is engaged at the spool  20 . This spiral spring  34  biases the spool  20  in the winding-up direction. 
         [0037]    The biasing force of this spiral spring  34  (the winding-up force of the webbing  28  based on that biasing force) is set relatively weakly, and to such a degree that looseness of the webbing  28  worn by a passenger is eliminated. In other words, the biasing force of the spiral spring  34  is set at a strength that will not give an oppressive feeling to a passenger when the webbing  28  is worn, not being required to be of a strength that causes the webbing  28  taken out from the spool  20  to be wound up to the last against the friction force or the like. 
         [0038]    Further, the spool  20  comprises a pivot portion (not shown) protruding coaxially from the end portion on the flange part  26  side. This pivot portion substantially coaxially penetrates into an internally toothed ratchet hole  36  formed in the foot plate  18  to protrude to the outside of the frame  12 , and is rotatably pivotally-supported by a substantially cup-like casing  40  that is fixed with the opening end being butted against the outside surface of the foot plate  18  and constitutes a lock mechanism  38 . 
         [0039]    The lock mechanism  38  normally tolerates free rotation of the spool  20  in both of the winding-up direction and the taking-out direction, and, and prevents the rotation of the spool  20  in the taking-out direction at the time of vehicle rapid deceleration. In the present first embodiment, when an acceleration sensor  41  prevents a ratchet gear  42  from rotating in the taking-out direction, the relative rotation between the ratchet gear  42  and the spool  20  causes a lock plate  46  to protrude from a lock base  44  and engage with the internal teeth of the ratchet hole  36  in the foot plate  18 , resulting in the rotation of the spool  20  in the taking-out direction being prevented. Between the lock base  44  and the spool  20 , a torsion bar may be connected to provide a configuration in which, after the above-mentioned locking, the torsion bar is twisted while the rotation of the spool  20  in the taking-out direction is allowed to achieve energy absorption (achieve a force limiter function). 
         [0040]    Further, a motor  60  is disposed between the foot plate  16  and the foot plate  18  under the spool  20 . The motor  60  has an output shaft  62 , on which a gear  64  is coaxially and integrally provided. 
         [0041]    Above the gear  64  in the radial direction, a gear  66  having a diameter larger than that of the gear  64  is disposed. The gear  66  is engaged with the gear  64 , in a state in which the gear  66  is rotatably pivotally-supported by a support plate  68  provided between the foot plates  16 ,  18  and the foot plate  16  around an axis parallel with the axis of the spool  20 . In addition, at a lateral side of the gear  66  in the axial direction, a gear  70  having a diameter smaller than that of the gear  66  is coaxially and integrally provided with respect to the gear  66 . 
         [0042]    Further, above the gear  70  in the radial direction, a clutch  72  is provided. The clutch  72  comprises an externally toothed gear  74  formed in the shape of a ring. The gear  74  is provided coaxially and relatively rotatably with respect to the spool  20  in a state in which it is engaged with the gear  70 , and both ends thereof in the axial direction are blocked with disk-like members (not shown). In addition, inside of the gear  74 , an adapter  76  in the shape of a cylinder is provided coaxially with respect to the spool  20 . The adapter  76  is connected integrally with the spool  20 , penetrating into the disk-like members that block both ends of the gear  74 , to rotatably pivotally-support the disk-like members, and thus the gear  74 , around the spool  20 . 
         [0043]    Inside of the gear  74 , a connecting member (not shown), such as a pawl which is rocked by the centrifugal force, or the like, is accommodated. This connecting member is supported, for example, by the above-mentioned disk-like members, and rotates integrally with the gear  74 . 
         [0044]    Herein, with the clutch  72 , the rotating force of the output shaft  62  of the motor  60  is transmitted to the gear  74  via the gear  64 , the gear  66 , and the gear  70  (the output shaft  62  and the gear  74  always rotate in synchronism with each other), and when the output shaft  62  of the motor  60  rotates in the forward direction, the gear  74  rotates in the winding-up direction. When the gear  74  rotates in the winding-up direction, the connecting member is mechanically connected to the circumferential surface of the adapter  76 , resulting in the gear  74  and the adapter  76  being integrally connected to each other. Thereby, the rotation of the gear  74  in the winding-up direction (the forward running of the motor  60 ) is transmitted to the spool  20  via the adapter  76 . 
         [0045]    On the other hand, when the output shaft  62  of the motor  60  rotates in the reverse direction, the gear  74  rotates in the taking-out direction. In this case, when the gear  74  relatively rotates in the taking-out direction by a predetermined amount with respect to the adapter  76  (when the reverse running of the motor  60  causes the output shaft  62  to relatively rotate with respect to the spool  20  by a predetermined amount), the mechanical connection of the connecting member to the adapter  76  is released, and the clutch  72  is brought into a disengaged state. 
         [0046]    In addition, on the other hand, the present motor retractor  10  comprises a driver  82  and an ECU  86  constituting a control portion. A driving control program according to the first embodiment of the present invention is stored in the ECU  86 . In addition, the motor  60  is electrically connected to a battery  84  loaded on a vehicle via the driver  82 , and with the current from the battery  84  flowing to the motor  60  via the driver  82 , the motor  60  exerts a driving force to rotate the output shaft  62  in the forward or reverse direction. The driver  82  is connected to the ECU  86 , and whether power is to be fed to the motor  60  via the driver  82 , and the direction and magnitude of the supply current are controlled by the ECU  86 . 
         [0047]    Further, a buckle switch  92  serving as the control portion for detecting whether or not a tongue plate provided at the webbing  28  is connected to the buckling apparatus (both not shown) is connected to the ECU  86 . When the tongue plate is connected to the buckling apparatus, the buckle switch  92  outputs, to the ECU  86 , a signal at an H level indicating that the switch is in the ON state, and, when the tongue plate is disconnected from the buckling apparatus, the buckle switch  92  outputs, to the ECU  86 , a signal at an L level indicating that the switch is in the OFF state. When the signal outputted from the buckle switch  92  is a signal at an L level, the ECU  86  determines that the webbing  28  is stored in the retractor. 
         [0048]    In addition, a lock current detection circuit  98  that is a component of the control portion is connected to the ECU  86 . This lock current detection circuit  98  is connected to the motor  60  via the driver  82 , and when an external force resisting the rotation of the output shaft  62  acts, resulting in the motor  60  being overloaded, and the magnitude of the current flowing to the motor  60  (the driver  82 ) is increased beyond a previously set threshold value IL (when a so-called lock current flows to the motor  60 ), the lock current detection circuit  98  outputs a predetermined electric signal (hereinafter, this signal is referred to as the “lock detection signal”) to the ECU  86 . 
         [0049]      FIG. 2A  to  FIG. 2D  are timing charts illustrating the relationship between the current to be supplied to the motor  60  by the ECU  86  and the driver  82  when the motor retractor  10  is to store the webbing  28 , and time. 
         [0050]    In the motor retractor  10 , the ECU  86  and driver  82  start to supply a current having a predetermined current value I 0  to the motor  60  for rotating the motor  60  in the forward direction at the time point (a time point of T 0  in  FIG. 2A ) when it is detected that the tongue plate provided at the webbing  28  has been disconnected from the buckling apparatus (the passenger having released the wearing state of the webbing  28 ). In this case, on the basis of the adequate storing speed (the adequate winding-up speed) for the webbing  28 , the magnitude of the current value I 0  is set such that the magnitude of the current value I 0  is smaller than the threshold value IL of the lock current set for the lock current detection circuit  98  (such that I 0 &lt;IL). 
         [0051]    Further, at the time point when the time previously set for the ECU  86  has elapsed (a time point of T 1  in  FIG. 2A ), the ECU  86  determines that the amount of winding-up of the webbing  28  on to the spool  20  has reached the previously set amount (for example, about half), and as shown in  FIG. 2A , outputs, to the driver  82 , a signal for lowering the magnitude of the supply current to the motor  60  from the current value I 0  to a current value I 1 . Further, at the time point when a predetermined time has elapsed from this lowering of the current value (a time point of T 2  in  FIG. 2A ), the ECU  86  determines that the webbing  28  has been fully stored on the present motor retractor  10  and outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 . In addition, in the motor retractor  10 , when a predetermined time has elapsed after the power feeding to the motor  60  has been interrupted at the time point of T 2 , the ECU  86  and the driver  82  perform the power feeding control as shown in  FIG. 2A  (hereinafter, to be called the “full operation control”) several times before terminating the control of power feeding to the motor  60 . 
         [0052]    On the other hand, when an overload on the motor  60  is detected during the winding-up of the webbing  28 , that is, when a lock detection signal is outputted from the lock current detection circuit  98  to the ECU  86 , the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , and further, after a predetermined time has elapsed, outputs, to the driver  82 , a signal for redriving the motor  60 . 
         [0053]    Furthermore, at the time of the redriving, the ECU  86  and the driver  82  detect the amount of winding-up of the webbing  28  onto the spool  20  at the time of the above-mentioned overload detection on the basis of the time for driving the motor  60  that has elapsed before the lock detection signal is inputted, that is, the time TL from the time point when the driving of the motor  60  has been started (the time point of T 0 ) to the time point when the lock detection signal is inputted (hereinafter, referred to as the “lock detection time TL”), and adjust the driving state of the motor  60  according to the length of this lock detection time TL. 
         [0054]    That is, when a lock current detection signal is inputted to the ECU  86  at a certain time point in an early stage of winding-up of the webbing  28  (at a time point of T 3  in  FIG. 2B , for example, in a case where the lock detection time TL is short), the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , and thereby the power feeding to the motor  60  is interrupted at a time point of T 4  in  FIG. 2B . In this case, the ECU  86  determines that the amount of winding-up of the webbing  28  onto the spool  20  is small, that is, the webbing  28  has hardly been stored on the retractor, and after a predetermined time has elapsed (at a time point of T 5  in  FIG. 2B ), starts the above-mentioned “full operation control”. That is, the ECU  86  and the driver  82  start to supply the current having a current value of I 0  to the motor  60  at the time point of T 5  in  FIG. 2B ; lower the magnitude of the supply current to the motor  60  from the current value I 0  to the current value I 1  at a time point of T 6  in  FIG. 2B ; and interrupt the power feeding to the motor  60  at a time point of T 7  in  FIG. 2B . 
         [0055]    On the other hand, when a lock current detection signal is inputted to the ECU  86  at a certain time point in a later stage of winding-up of the webbing  28  (at a time point of T 8  in  FIG. 2C , for example, in a case where the lock detection time TL is long), the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , and thereby the power feeding to the motor  60  is interrupted at a time point of T 9  in  FIG. 2B . In this case, the ECU  86  determines that the amount of winding-up of the webbing  28  on the spool  20  is large, that is, that most of the webbing  28  has been stored in the retractor, and after a predetermined time has elapsed (at a time point of T 10  in  FIG. 2C ), outputs, to the driver  82 , a signal for supplying a current having a current value of I 2  to the motor  60 , thereby driving the motor  60  at a low output. In the present first embodiment, the magnitude of the current value I 2  is set smaller than the current value I 0  (I 2 &lt;I 0 ), and the motor  60  is driven in a mode which is the weakest next to the stopped state. 
         [0056]    Furthermore, at a time point of T 11  in  FIG. 2C , the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , and thereby the motor  60  is stopped. The time for power feeding to the motor  60  (from T 10  to T 11 ) at this time is shorter than the time for power feeding to the motor  60  in the “full operation control” (from T 0  to T 2  or from T 5  to T 7 ), and the motor  60  is driven for a shorter time. 
         [0057]    In addition, when a lock current detection signal is inputted to the ECU  86  at a certain time point in a middle stage of winding-up of the webbing  28  (at a time point of T 12  in  FIG. 2D , for example, in a case where the lock detection time TL is of a medium length), the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , and thereby the power feeding to the motor  60  is interrupted at a time point of T 13  in  FIG. 2D . In this case, the ECU  86  determines that the amount of winding-up of the webbing  28  onto the spool  20  is approx. half of that to be obtained at the time of full storage on the retractor, and after a predetermined time has elapsed (at a time point of T 14  in  FIG. 2D ), outputs, to the driver  82 , a signal for supplying a current having a current value of I 3  to the motor  60 , and thereby driving the motor  60  being driven at a low output. In the present first embodiment, the magnitude of the current value I 3  is set at a value equal to or greater than the current value I 2  and smaller than the current value I 0  (I 2 &lt;I 3 &lt;I 0 ). 
         [0058]    Further, at a time point of T 15  in  FIG. 2D , the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 , thereby stopping the motor  60 . In this case, the time for power feeding to the motor  60  (from T 14  to T 15 ) is shorter than the time for power feeding to the motor  60  in the “full operation control” (from T 0  to T 2  or from T 5  to T 7 ), and longer than the time for power feeding to the motor  60  when the motor has been overloaded in a later stage of winding-up of the webbing  28  (from T 10  to T 11 ). Therefore, the motor  60  is driven for a time shorter than that in the “full operation control” and longer than that in a case where the motor  60  has been overloaded in a later stage of winding-up of the webbing  28 . 
         [0059]    Next, the function of the present first embodiment will be described. 
         [0060]    With the motor retractor  10  as configured above, when the passenger takes out the webbing  28  stored in the present motor retractor  10  to connect the tongue plate (not shown) provided at the webbing  28  to the buckling apparatus, a state in which the passenger wears the webbing  28  is achieved. In this wearing state, the webbing  28  restrains the passenger relatively weakly by the biasing force of the spiral spring  34 . 
         [0061]    On the other hand, when the passenger releases the connection state between the tongue plate and the buckling apparatus to release the wearing state of the webbing  28 , the motor  60  is driven, and the winding-up of the webbing  28  is started. Then, when the webbing  28  is wound up to approx. half of the amount of winding-up at the time of full storage on the retractor, the driving force and the rotation speed of the motor  60  are lowered. Thereby, the webbing  28  is slowly wound up with a small force. Then, when a predetermined time (the time necessary for fully storing the webbing  28  on the retractor with the “full operation control”) has elapsed from the start of winding-up of the webbing  28 , the motor  60  is stopped. 
         [0062]    On the other hand, when, in the early stage of winding-up the webbing  28 , the passenger&#39;s arm, or the like, gets caught by the webbing  28 , resulting in the motor  60  being overloaded, the motor  60  is stopped, and the winding-up of the webbing  28  is interrupted. Then, when a predetermined time (the time necessary for the passenger to release their arm, or the like, from the webbing  28 ) has elapsed, the motor  60  is redriven. In this case, because the webbing  28  has hardly been stored on the retractor  10 , the motor  60  is driven with the “full operation control”; however, even in a case where the passenger has not released their arm, or the like, from the webbing  28  within the above-mentioned predetermined time, the sense of discomfort given to the passenger is minimal, because the amount of taking-out of the webbing  28  is large. In addition, even after the motor  60  has been redriven, the passenger will have enough time for releasing their arm, or the like. 
         [0063]    In addition, when, in the later stage of winding-up of the webbing  28 , the passenger&#39;s arm, or the like, gets caught by the webbing  28 , resulting in the motor  60  being overloaded, the motor  60  is stopped, and the winding-up of the webbing  28  is interrupted. Then, when a predetermined time (the time necessary for the passenger to release their arm, or the like, from the webbing  28 ) has elapsed, the motor  60  is redriven. In this case, because most of the webbing  28  has been stored on the retractor, the motor  60  is driven at a low output for a short time. Therefore, even in case where the passenger has not released their arm, or the like, from the webbing  28 , within the above-mentioned predetermined time, the sense of discomfort given to the passenger by the motor  60  being redriven can be reduced. In addition, because the time for driving the motor  60  is short, unnecessary driving of the motor  60  after completion of the winding-up of the webbing  28  can be prevented, and thus the occurrence of noise due to the unnecessary driving of the motor  60  can be suppressed. 
         [0064]    In addition, when, in the middle stage of winding-up of the webbing  28 , the passenger arm, or the like, gets caught by the webbing  28 , resulting in the motor  60  being overloaded, the motor  60  is stopped, and the winding-up of the webbing  28  is interrupted. Then, when a predetermined time (the time necessary for the passenger to release their arm, or the like, from the webbing  28 ) has elapsed, the motor  60  is redriven. In this case, because approx. half of the webbing  28  has been stored on the retractor, the motor  60  is driven at a low output for a predetermined time, that is, for a time shorter than that in the “full operation control”, and longer than that in a case where the motor  60  has been overloaded in the later stage of winding-up of the webbing  28 . Therefore, the sense of discomfort given to the passenger at the time of the motor  60  being redriven can be reduced, and the occurrence of noise after the completion of the winding-up of the webbing  28  can be suppressed. 
         [0065]    As described above, with the motor retractor  10  according to the first embodiment of the present invention, even when the winding-up of the webbing  28  is resumed in a state in which the catching thereof by an arm, or the like, has not been released, the sense of discomfort given to a passenger can be reduced. 
         [0066]    Furthermore, in the motor retractor  10  according to the first embodiment of the present invention, the ECU  86  detects whether the amount of winding-up of the webbing  28  onto the spool  20  has reached a previously set amount, on the basis of the lock detection time TL (the time from the start of winding-up of the webbing  28  to the detection of the locking of the motor  60 ), and thus the configuration of the motor retractor  10  is simple. Means for detecting the amount of winding-up the webbing  28  (such as a sensor for detecting the amount of rotation of the spool  20 , or the like) may be separately provided. 
         [0067]    In addition, the above-mentioned first embodiment has been provided with a configuration in which, by changing the magnitude of the supply current to the motor  60 , the driving state of the motor  60  is adjusted; however, besides this configuration, the first embodiment may be adapted to have a configuration in which, by changing the magnitude of the voltage to be applied to the motor  60 , the driving state of the motor  60  is adjusted. In a case where a configuration in which the motor  60  is controlled with the voltage is provided, even when, for example, the motor  60  is driven in a state in which the engine of the vehicle is stopped, resulting in the power supply voltage becoming unstable, the rotation speed of the motor  60 , that is, the speed of winding-up the webbing  28  can be kept constant without being influenced by fluctuations in the power supply voltage. 
       Second Embodiment 
       [0068]    Next, a second embodiment of the present invention will be described. For configurations and functions that are essentially the same as those of the first embodiment, the same reference numerals as those in the first embodiment are provided, and description thereof is omitted. 
         [0069]      FIG. 1  is a front sectional view illustrating the overall configuration of a motor retractor  100  according to a second embodiment of the present invention. 
         [0070]    This motor retractor  100  is provided with basically the same configuration as that of the motor retractor  10  according to the first embodiment; however, a driving control program which is different from the driving control program according to the first embodiment is stored in the ECU  86 . 
         [0071]      FIG. 3  is a timing chart illustrating the relationship between the current to be supplied to the motor  60  by the ECU  86  and the driver  82  when the motor retractor  100  according to the second embodiment of the present invention stores the webbing  28 , and the time. 
         [0072]    In the motor retractor  100 , the ECU  86  and the driver  82  start to supply a current having a predetermined current value of I 0  to the motor  60  to drive the motor  60  at the time point (a time point of T 0  in  FIG. 3 ) when it is detected that the tongue plate provided at the webbing  28  has been disconnected from the buckling apparatus (the passenger having released the wearing state of the webbing  28 ). Thereby, the winding-up of the webbing  28  is started. At the time of driving the motor  60 , a rush current IS flows to the motor  60  as shown in  FIG. 3 , and the motor  60  is rapidly driven, however, at this time point, the passenger&#39;s arm, or the like, will not get caught by the webbing  28 , and thus no sense of discomfort will be given to the passenger. 
         [0073]    Then, when, at a time point of T 1  in  FIG. 3 , for example, the passenger&#39;s arm, or the like, gets caught by the webbing  28 , resulting in the motor  60  being overloaded, the lock current detection circuit  98  outputs a lock detection signal to the ECU  86 , and the ECU  86  outputs, to the driver  82 , a signal for interrupting the power feeding to the motor  60 . Thereby, the motor  60  is stopped at a time point of T 2  in  FIG. 3 . 
         [0074]    Further, when, from the time point of T 2  in  FIG. 3 , a predetermined time (the time necessary for the passenger to release their arm, or the like, from the webbing  28 ) has elapsed and a time point of T 3  in  FIG. 3  is reached, the ECU  86  and the driver  82  resume the power feeding to the motor  60 , while gradually increasing the magnitude of the current. Thereby, the motor  60  starts the driving, while gradually increasing the driving force and the rotation speed, with the webbing  28  starting to be gradually wound up with a small force. Therefore, even in a case where, within the above-mentioned predetermined time, the passenger has not released their arm, or the like, from the webbing  28 , the sense of discomfort given to the passenger can be reduced. 
         [0075]    Then, when, at a time point of T 4  in  FIG. 3 , the current value of the supply current to the motor  60  has reached I 4 , the ECU  86  and the driver  82  terminate the increase in current, supplying a fixed current (a stationary current) with a current value of I 4  to the motor  60 . In this case, the rush current flowing to the motor  60  at the time point of T 4  in  FIG. 3  can be reduced, and thus the rush current can be prevented from causing the motor  60  to be rapidly driven, and thus the sense of discomfort given to the passenger can be suppressed. Furthermore, because the magnitude I 4  of the stationary current for the motor  60  after the resumption of the power feeding is set such that it is smaller than the magnitude I 0  of the stationary current for the motor  60  before the overload detection, the driving force and the rotation speed of the motor  60 , that is, the winding-up force and the winding-up speed for the webbing  28 , are also decreased. Therefore, the sense of discomfort given to the passenger can be further reduced.

Technology Category: 7