Seat belt retractor and seat belt device
First Claim
1. A seat belt retractor, comprising:
- a spool for winding up a seat belt;
a motor configured to generate rotational torque for rotating the spool; and
a power transmission mechanism configured to transmit the rotational torque of the motor to the spool, the seat belt being wound on the spool by the rotational torque of the motor, wherein the power transmission mechanism includes a low reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a high speed and with low torque and a high reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a low speed and with high torque, wherein the seat belt retractor further comprises a power transmission mode switching mechanism that selectively sets the power transmission mechanism into either the low reduction ratio power transmission mode or the high reduction ratio power transmission mode, and a controller configured to control the action of the power transmission mode switching mechanism to switch the mode between the low reduction ratio power transmission mode and the high reduction ratio power transmission mode by controlling the rotational direction of the motor to be changed between the normal direction or the reverse direction.
1 Assignment
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Accused Products
Abstract
A seat belt retractor is provided in which two winding performances are achieved while reduced power consumption of a motor and simplified control of the motor are also achieved. A clutch gear is meshed with a carrier gear by rotation of a motor in the normal direction. Accordingly, a low reduction ratio power transmission mode is set so that a seat belt is wound up at a high speed and with low torque. As slack of the seat belt is removed and the belt load increases, the clutch pawl becomes possible to be engaged with the internal gear. As the motor current increases and exceeds a preset value, the motor rotates reversely so that the clutch gear separates from the carrier gear. Therefore, a high reduction ratio power transmission mode is set so that the belt is wound up at a low speed and with high torque.
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Citations
19 Claims
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1. A seat belt retractor, comprising:
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a spool for winding up a seat belt;
a motor configured to generate rotational torque for rotating the spool; and
a power transmission mechanism configured to transmit the rotational torque of the motor to the spool, the seat belt being wound on the spool by the rotational torque of the motor, wherein the power transmission mechanism includes a low reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a high speed and with low torque and a high reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a low speed and with high torque, wherein the seat belt retractor further comprises a power transmission mode switching mechanism that selectively sets the power transmission mechanism into either the low reduction ratio power transmission mode or the high reduction ratio power transmission mode, and a controller configured to control the action of the power transmission mode switching mechanism to switch the mode between the low reduction ratio power transmission mode and the high reduction ratio power transmission mode by controlling the rotational direction of the motor to be changed between the normal direction or the reverse direction. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A seat belt device, comprising:
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a seat belt retractor configured to wind up a seat belt;
a tongue that is slidably supported to the seat belt; and
a buckle releasably latched to the tongue, wherein the seat belt retractor includes;
a spool for winding up the seat belt;
a motor configured to generate rotational torque for rotating the spool; and
a power transmission mechanism configured to transmit the rotational torque of the motor to the spool, the seat belt being wound on the spool by the rotational torque of the motor, wherein the power transmission mechanism includes a low reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a high speed and with low torque and a high reduction ratio power transmission mode in which the rotational torque of the motor is transmitted to the spool at a low speed and with high torque, wherein the seat belt retractor further comprises a power transmission mode switching mechanism that selectively sets the power transmission mechanism into either the low reduction ratio power transmission mode or the high reduction ratio power transmission mode, and a controller configured to control the action of the power transmission mode switching mechanism to switch the mode between the low reduction ratio power transmission mode and the high reduction ratio power transmission mode by controlling the rotational direction of the motor to be changed between the normal direction or the reverse direction. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A seat belt device including a retractor for winding up a seatbelt and a controller configured to change the rotational direction of a retractor motor between the normal direction and the reverse direction, wherein the retractor is configured to switch between a low reduction ratio power transmission mode and a high reduction ratio power transmission mode when the rotational direction of the retractor motor is changed.
Specification