초록 ▼

A spindle (2) of a seat belt retractor is rotationally driven when required by a motor (5) to the webbing take-up direction side through a power transmission mechanism section (6). Further, the spindle (2) is always connected to a take-up spring (7) and is always subjected to rotational power acting

A spindle (2) of a seat belt retractor is rotationally driven when required by a motor (5) to the webbing take-up direction side through a power transmission mechanism section (6). Further, the spindle (2) is always connected to a take-up spring (7) and is always subjected to rotational power acting to the webbing take-up side. The structure enables a user wearing a seat belt to be restrained even in failure, realizing a safer and more reliable restraining device.

대표청구항 ▼

1. A retractor for a seat belt system for a vehicle comprising: a spindle on which a webbing is wound;a frame for pivotally holding the spindle;a spindle locking system means for stopping rotation of the spindle rotating in a webbing drawing out direction when at least one of the two following crite

1. A retractor for a seat belt system for a vehicle comprising: a spindle on which a webbing is wound;a frame for pivotally holding the spindle;a spindle locking system means for stopping rotation of the spindle rotating in a webbing drawing out direction when at least one of the two following criteria is met: a rotational acceleration of the spindle is greater than a first predetermined value when the webbing is accelerated in the drawing out direction; anda deceleration of the vehicle is greater than a second predetermined value;a motor which generates a motor torque to rotate the spindle in the winding direction;a torque transmitting mechanism system which transmits the motor torque to the spindle,a control system for controlling the torque generated by the motor according to a seat belt fastening state and a dangerous state, the seat belt fastening state being one of a fastened seat belt state and a non-fastened seat belt state;a winding spring which generates a spring torque to rotate the spindle in a winding direction in which the webbing is wound onto the spindle, the winding spring being connected to the spindle at all times so as to transmit the generated spring torque to the spindle and being set to generate a spring torque insufficient for completely winding the webbing onto the spindle absent any other forces while the seat belt fastening state is the non-fastened seat belt state;a torque transmission cushioning system for cushioning a torque transmission by an elastic member arranged between the motor and the spindle, wherein when the motor torque is transmitted to the spindle, a sudden change in the motor torque is not transmitted to the spindle as a sudden change in torque, and wherein when the motor torque is transmitted to the spindle, a sudden force given to the spindle in the drawing out direction is not transmitted to the motor as a sudden change in force, the torque transmission cushioning system configured to be activated and deactivated by a clutch,a seat belt fastening state detecting system incorporated into a buckle, the seat belt fastening detection system being operable to detect the seat belt fastening state based on whether or not a tongue is engaged with the buckle; anda dangerous state detecting system for detecting whether or not the vehicle is in the dangerous state,wherein the motor is operated repeatedly, and the spring torque is configured to maintain a lower rotary speed of the spindle than the motor torque,wherein the control system is configured to compare an actual amount of drawing of the webbing determined by a count of an angular counter with a predetermined amount of drawing of the webbing when the seat belt fastening state is the non-fastened seat belt state, the predetermined amount being less than an amount of drawing of the webbing necessary for restricting a passenger seated in the seat, the control system further being configured to judge that the webbing cannot be wound only by the winding spring when the actual amount of drawing of the webbing is less than the predetermined amount and to activate the motor to wind up the webbing during the non-fastened seat belt state when the two following conditions are simultaneously met: that the actual amount of drawing of the webbing is less than the predetermined amount; andthat the-spindle has stopped moving. 2. The retractor for the seat belt system according to claim 1, wherein the winding spring is a spiral spring. 3. The retractor for the seat belt system according to claim 1, wherein when the motor generates the motor torque for rotating the spindle in the winding direction, the torque transmitting mechanism system transmits the motor torque to the spindle, and when the motor generates a second torque for rotating the spindle in the drawing out direction, the torque transmitting mechanism system does not transmit the second torque to the spindle. 4. The retractor for the seat belt system according to claim 3, wherein when the control system makes the motor generate the second torque in the drawing out direction, and when the webbing detecting system detects that an amount of webbing being drawn is greater than a third predetermined value, the control system makes the motor increase a rotary speed. 5. The retractor for the seat belt system according to claim 1, wherein the winding spring has a preset spring torque setting so that a predetermined tension is generated in the webbing when a seat belt user fastens the seat belt. 6. The retractor for the seat belt system according to claim 1, wherein an elastic force of the elastic member in the power transmission cushioning system is larger than the force generated by the winding spring when the elastic member is substantially compressed. 7. The retractor for the seat belt system according to claim 1, wherein when the fastened seat belt state and the dangerous state of the vehicle are detected, the control system makes the motor generate the motor torque for rotating the spindle in the winding direction. 8. The retractor for the seat belt according to claim 1, wherein when the fastened seat belt state and a change from the dangerous state of the vehicle to a not-dangerous state are detected, the control system makes the motor generate the motor torque at a level for rotating the spindle in the winding direction for a predetermined period of time; and wherein the control system further makes the motor gradually reduce the torque with lapse of time, such that when the motor stops generating the torque, the control system makes the motor generate a predetermined second torque for rotating the spindle in the drawing out direction for a predetermined period of time. 9. A retractor for a seat belt system for a vehicle comprising: a spindle on which a webbing is wound;a frame for pivotally holding the spindle;a spindle locking system means for preventing the webbing from drawing out and for stopping rotation of the spindle rotating in a webbing drawing out direction when at least one of the two following criteria is met: a rotational acceleration of the spindle is greater than a first predetermined value when the webbing is accelerated in the drawing out direction; anda deceleration of the vehicle is greater than a second predetermined value;a motor which generates a motor torque to rotate the spindle in the winding direction; anda torque transmitting mechanism system which transmits the motor torque to the spindle;a webbing action detecting system for detecting a webbing action, the webbing action being one of a webbing drawing out state, a webbing winding state, and a webbing stoppage state;a control system for controlling the motor torque according to a seat belt fastening state and the webbing action detected by the webbing action detecting system, the seat belt fastening state being one of a fastened seat belt state and a non-fastened seat belt state;a winding spring which generates a spring torque to rotate the spindle in a winding direction in which the webbing is wound onto the spindle, the winding spring being connected to the spindle at all times so as to transmit the generated spring torque to the spindle and being set to generate a spring torque insufficient for completely winding the webbing onto the spindle absent any other forces while the seat belt fastening state is the non-fastened seat belt state;a torque transmission cushioning system for cushioning a torque transmission by an elastic member arranged between the motor and the spindle, wherein when the motor torque is transmitted to the spindle, a sudden change in the motor torque is not transmitted to the spindle as a sudden change in torque, and when the motor torque is transmitted to the spindle, a sudden force given to the spindle in the drawing out direction is not transmitted to the motor as a sudden change in force, the torque transmission cushioning system configured to be activated and deactivated by a clutch; anda seat belt fastening detection system integrated into a buckle, the seat belt fastening detection system being operable to detect the seat belt fastening state based on whether or not a tongue is engaged with the buckle,wherein the motor is used repeatedly,wherein the control system is configured to determine whether a vehicle door associated with the retractor is currently closed and to compare an actual amount of drawing of the webbing determined by a count of an angular counter with a predetermined amount of drawing of the webbing when the seat belt fastening state is the non-fastened seat belt state, the predetermined amount being less than an amount of drawing of the webbing necessary for restricting a passenger seated in the seat, the control system further being configured to judge that the webbing cannot be wound only by the winding spring only when three conditions are simultaneously met: that the actual amount of drawing of the webbing is less than the predetermined amount;that the-spindle has stopped moving; andthat the seat belt fastening state is the non-fastened seat belt state;wherein the spring torque is configured to remove slack in the seat belt webbing when the tongue is engaged with the buckle, but constantly incapable of completely winding up the webbing when the tongue is not engaged with the buckle. 10. The retractor for the seat belt system according to claim 9, wherein when the seat belt fastening detecting system detects a change from the fastened seat belt state to the non-fastened seat belt state, and the webbing action detecting system further detects that the webbing is in the webbing stoppage state, the control system makes the motor generate a predetermined intensity of the motor torque for rotating the spindle in the winding direction. 11. The retractor for the seat belt system as set forth in claim 10, wherein the control system makes the motor generate the motor torque at a level greater than a predetermined level of torque required for rotating the spindle in the winding direction. 12. The retractor for the seat belt system according to claim 9, wherein when the non-fastened seat belt state, the webbing drawing out state, and the webbing stoppage state are detected, the control system makes the motor generate a predetermined intensity of the motor torque for rotating the spindle in the winding direction. 13. The retractor for the seat belt system according to claim 9, wherein when the non-fastened seat belt state and a webbing stoppage state are detected, and when the motor is generating the motor torque for rotating the spindle in the winding direction, the control system stops the generation of the motor torque for a predetermined period of time, and then the control system controls the motor to generate a second torque in the drawing direction. 14. The retractor for the seat belt system according to claim 9, wherein when a change from the non-fastened seatbelt state to the fastened seat belt state is detected, the control system makes the motor generate the motor torque for rotating the spindle in the winding direction, and when the webbing stoppage state is detected, the control system makes the motor generate a second torque to rotate the spindle in the drawing out direction for a predetermined period of time. 15. The retractor for the seat belt system according to claim 9, wherein the webbing action detecting system detects the webbing action by detecting a rotary speed and a rotary direction of the spindle, wherein when the webbing action detection system detects a predetermined increase in the rotary speed of the spindle in a predetermined period of time, the webbing action detection system determines that the webbing is in the webbing drawing out state if the webbing action detection system further detects that the rotary direction of the spindle corresponds to the drawing out direction, and the webbing action detecting system determines that the webbing is in the webbing winding state if the webbing action detection system further detects that the rotary direction of the spindle corresponds to the winding direction, andwherein the webbing action detection system determines that the webbing is in the webbing stoppage state when the webbing is not in either the webbing drawing out state or the webbing winding state. 16. The retractor for the seat belt system according to claim 9, further comprising: a dangerous state detecting system for detecting whether or not a vehicle is in a dangerous state, the dangerous state being one of an actual or potential collision,wherein when the dangerous state detecting system detects the dangerous state and the seat belt fastening detection system detects a fastened seat belt state, the control system makes the motor generate the motor torque for rotating the spindle in the winding direction. 17. The retractor for the seat belt system according to claim 16, wherein when a change from the dangerous state of the vehicle to a not-dangerous state is detected, the control system makes the motor generate the motor torque for rotating the spindle in the winding direction for a predetermined period of time and at a level higher than a predetermined level of torque required for rotating the spindle, and wherein the control system further makes the motor gradually reduce the motor torque with lapse of time, such that when the motor stops generating the torque, the control system makes the motor generate a predetermined intensity of a second torque for rotating the spindle in the drawing out direction for a predetermined period of time. 18. The retractor for the seat belt system according to claim 16, wherein when the dangerous state of the vehicle and a change from the fastened seat belt state to the non-fastened seat belt state are detected, the control system makes the motor generate a predetermined second torque for rotating the spindle in the drawing out direction for a predetermined period of time. 19. The retractor for the seatbelt system according to claim 9, wherein the webbing action detecting system detects the webbing action by detecting a rotary speed and a rotary direction of the spindle.