IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0248182
(2002-12-24)
|
우선권정보 |
JP-0396614 (2001-12-27) |
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
14 인용 특허 :
1 |
초록
▼
A seat belt retractor having a force limiter mechanism that can be stably operated when a pyrotechnic pretensioner is activated. As a pyrotechnic pretensioner is activated, a ring gear rotates in the counter-clockwise direction. Accordingly, an external tooth holding an end portion of a stopper is m
A seat belt retractor having a force limiter mechanism that can be stably operated when a pyrotechnic pretensioner is activated. As a pyrotechnic pretensioner is activated, a ring gear rotates in the counter-clockwise direction. Accordingly, an external tooth holding an end portion of a stopper is moved, whereby the end portion of the stopper becomes free. Therefore, the stopper expands because of its biasing force. Then, a release spring is released from the restriction of the stopper and thus pivots in the clockwise direction because of its biasing force. The release spring collides with a pin of the clutch pawl to press down the pin. Therefore, the clutch pawl is rotated about a clutch pawl pin in the clockwise direction, thereby canceling the mechanical connection between the motor and the spool.
대표청구항
▼
1. A seat belt retractor comprising:a motor for rotating a spool to wind up a seat belt; a power transmission switching mechanism which, in a connected state, allows the spool to rotate only in a seat belt winding direction and which, in a disconnected state, allows the spool to rotate in both direc
1. A seat belt retractor comprising:a motor for rotating a spool to wind up a seat belt; a power transmission switching mechanism which, in a connected state, allows the spool to rotate only in a seat belt winding direction and which, in a disconnected state, allows the spool to rotate in both directions; a force limiter mechanism which allows the spool to rotate in a seat belt withdrawing direction against a rotation limiting force when a force to rapidly withdraw the seat belt is applied; and a pyrotechnic pretensioner which forces to wind up the seat belt at the time of detection of a collision, wherein the power transmission switching mechanism is set into the disconnected state by the movement of a mechanical portion of the pyrotechnic pretensioner which moves when the pyrotechnic pretensioner is activated, thereby disconnecting the mechanical connection of the motor and the spool. 2. The seat belt retractor as claimed in claim 1, wherein the power transmission switching mechanism includes a ratchet wheel; andwherein the connected state and the disconnected state are switched depending on the presence or absence of engagement between a stopping member, which is driven by the rotational force of the motor in the seat belt winding direction, and the ratchet wheel; and wherein the stopping member is configured to be released from engagement with the ratchet wheel by the movement of the mechanical portion of the pyrotechnic pretensioner which moves when the pyrotechnic pretensioner is activated. 3. The seat belt retractor as claimed in claim 2, further comprising a control lever which is rotatable under the rotational torque of the motor; andwherein the control lever drives the stopping member to control the engagement between the stopping member and the ratchet wheel. 4. The seat belt retractor as claimed in claim 2, further comprising a reduction mechanism which reduces the speed of rotation of the motor and transmits the rotation of the motor to the spool; andwherein the reduction mechanism comprises a sun gear to which the rotation of the motor is transmitted, a ring-shaped internal gear which is rotatably disposed and has ratchet teeth on the external periphery thereof and inner teeth on the internal periphery thereof, a planetary gear which is meshed with both the sun gear and the internal gear, and a carrier which supports the planetary gear such that the planetary gear can rotate on the own axis and transmits the revolution of the planetary gear to the spool; wherein the power transmission switching mechanism further comprises a stopping lever which is adapted to pivot between the disengaging position where the stopping lever is not engaged with the ratchet teeth and the engaging position where the stopping lever can be engaged with the ratchet teeth; wherein when a control lever does not rotate, the stopping lever is set in the disengaging position to allow the internal gear to freely rotate, and when the control lever rotates, the stopping lever is set in the engaging position so as to engage the stopping lever with the ratchet teeth, thereby preventing the rotation of the internal gear, and wherein when the rotation of the internal gear is prevented, the power transmission switching mechanism is set in the connected state and when the rotation of the internal gear is free, the power transmission switching mechanism is set in the disconnected state. 5. The seat belt retractor as claimed in claim 3, further comprising a reduction mechanism which reduces the speed of rotation of the motor and transmits the rotation of the motor to the spool;wherein the reduction mechanism comprises a sun gear to which the rotation of the motor is transmitted, a ring-shaped internal gear which is rotatably disposed and has ratchet teeth on the external periphery thereof and inner teeth on the internal periphery thereof, a planetary gear which is meshed with both the sun gear and the internal gear, and a carrier which supports the planetary gear such that the planetary gear can rotate on the own axis and transmits the revolution of the planetary gear to the spool, and wherein the power transmission switching mechanism further comprises a stopping lever which is capable of pivoting between a disengaging position where the stopping lever is not engaged with the ratchet teeth and an engaging position where the stopping lever can be engaged with the ratchet teeth, wherein when the control lever does not rotate, the stopping lever is set in the disengaging position to allow the internal gear to freely rotate, and when the control lever rotates, the stopping lever is set in the engaging position so as to engage the stopping lever with the ratchet teeth, thereby preventing the rotation of the internal gear; and wherein when the rotation of the internal gear is prevented, the power transmission switching mechanism is set in the connected state and when the rotation of the internal gear is free, the power transmission switching mechanism is set in the disconnected state. 6. A seat belt retractor as claimed in claim 2, further comprising a reduction mechanism which reduces the speed of rotation of the motor and transmits the rotation of the motor to the spool;wherein the reduction mechanism comprises a sun gear for transmitting the rotation of the motor to the spool, a ring-shaped internal gear which is rotatably disposed and has ratchet teeth on the external periphery thereof and inner teeth on the internal periphery thereof, a planetary gear which is meshed with both the sun gear and the internal gear, and a carrier which supports the planetary gear such that the planetary gear can rotate on the own axis and also revolves the planetary gear by the rotation of the motor; and wherein the power transmission switching mechanism further comprises a stopping lever which is capable of pivoting between the disengaging position where the stopping lever is not engaged with the ratchet teeth and the engaging position where the stopping lever can be engaged with the ratchet teeth; wherein when a control lever does not rotate, the stopping lever is set in the disengaging position to allow the internal gear to freely rotate, and when the control lever rotates, the stopping lever is set in the engaging position so as to engage the stopping lever with the ratchet teeth, thereby preventing the rotation of the internal gear, and wherein when the rotation of the internal gear is free, the power transmission switching mechanism is set in the disconnected state and when the rotation of the internal gear is prevented, the power transmission switching mechanism is set in the connected state. 7. A seat belt retractor as claimed in claim 3, further comprising a reduction mechanism which reduces the speed of rotation of the motor and transmits the rotation of the motor to the spool;wherein the reduction mechanism comprises a sun gear for transmitting the rotation of the motor to the spool, a ring-shaped internal gear which is rotatably disposed and has ratchet teeth on the external periphery thereof and inner teeth on the internal periphery thereof, a planetary gear which is meshed with both the sun gear and the internal gear, and a carrier which supports the planetary gear such that the planetary gear can rotate on the own axis and also revolves the planetary gear by the rotation of the motor, and wherein the power transmission switching mechanism further comprises a stopping lever which is capable of pivoting between the disengaging position where the stopping lever is not engaged with the ratchet teeth and the engaging position where the stopping lever can be engaged with the ratchet teeth, wherein when the control lever does not rotate, i.e. in the normal state, the stopping lever is set in the disengaging position to allow the internal gear to freely rotate, and when the control lever rotates, the stopping lever is set in the engaging position so as to engage the stopping lever with the ratchet teeth, thereby preventing the rotation of the internal gear, and wherein when the rotation of the internal gear is free, the power transmission switching mechanism is set in the disconnected state and when the rotation of the internal gear is prevented, the power transmission switching mechanism is set in the connected state. 8. A seat belt retractor as claimed in claim 2, wherein the engagement of the stopping member relative to the ratchet wheel is cancelled by directly or indirectly utilizing the movement of a rotational body; the rotational body being directly or indirectly subjected to the pyrotechnic power generated at the time of the operation of the pyrotechnic pretensioner and is thus rotated, and which then transmits its rotation to the spool.9. A seat belt retractor as claimed in claim 8, wherein the pyrotechnic pretensioner has a pipe and balls arranged inside the pipe and transmits the pyrotechnic power to the balls, then transmits the force of the balls to external teeth of a wheel to rotate the wheel, and transmits the rotation of the wheel to the spool,wherein the seat belt retractor comprises a first elastic member which takes a form defined by the external teeth of the wheel in the normal state and changes its form because of its spring force when the wheel is rotated, and a second elastic member which takes a form defined by the first elastic member in the normal state and changes its form because of its spring force when the first elastic member changes its form, wherein the engagement of the stopping member relative to the ratchet wheel is cancelled by the biasing force of the second elastic member when changing its form.
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