Webbing take-up device
AssigneeKabushiki Kaisha Tokai Rika Denki Seisakusho
InventorsTakahiro Osaki, Takamasa Sato, Yuya Nagata, Tomonari Umakoshi, Takuhiro Saito
Life of this patent
Estimating the term…
Abstract
A webbing take-up device that includes: a cut-off section that cuts off transmission of rotation load along a rotation force transmission route from a second rotation force transmission mechanism to a spool via a first rotation force transmission mechanism due to the rotation load in a pull-out direction becoming a predetermined value or greater; and a resistance section that resists the rotation load during transmission of the rotation load, and that suppresses transmission of the rotation load along the rotation force transmission route in a case in which the rotation load is less than the predetermined value.
Claims4
A webbing take-up device comprising:
- a spool that takes up a webbing by rotating in a take-up direction, and that rotates in a pull-out direction opposite to the take-up direction by the webbing being pulled out;
- a first rotation force transmission mechanism that is capable of transmitting rotation force to the spool from an end of the spool, and that is capable of mechanically coupling with the spool by being input with rotation force in a first direction in a state in which the first rotation force transmission mechanism couples with the spool, the first rotation force transmission mechanism being capable of rotating the spool in the take up direction;
- a second rotation force transmission mechanism that is capable of transmitting rotation force to the spool from the end of the spool, and that is capable of rotating the spool in the take-up direction by being input with rotation force in a second direction opposite to the first direction;
- a cut-off section that cuts off transmission of a rotation load in a pull-out direction along a rotation force transmission route from the spool to the second rotation force transmission mechanism to the first rotation force transmission mechanism when the rotation load in the pull-out direction becomes a predetermined value or greater;
- and
- a means for both rotating the spool in a take-up direction and for providing a cut off rotation load to the cut-off section, including a motor having a motor output shaft coupled with the end of the spool by the first rotation force transmission mechanism and the second rotation force transmission mechanism, the motor rotating the motor output shaft when driven, the motor having a pre-selected cogging torque such that a product of a gear ratio of transmission of rotation force from the spool to the motor output shaft via the second rotation force transmission mechanism and a maximum value of the cogging torque becomes the predetermined value of the rotation load that causes the cut-off section to cut off transmission of the rotation load in the pull-out direction.
A method of operating a webbing take-up device that includes a spool that takes up a webbing by rotating in a take-up direction, and that rotates in a pull-out direction opposite to the take-up direction by the webbing being pulled out;
- a first rotation force transmission mechanism that is capable of transmitting rotation force to the spool from an end of the spool, and that is capable of mechanically coupling with the spool by being input with rotation force in a first direction in a state in which the first rotation force transmission mechanism couples with the spool, the first rotation force transmission mechanism being capable of rotating the spool in the take up direction;
- a second rotation force transmission mechanism that is capable of transmitting rotation force to the spool from the end of the spool, and that is capable of rotating the spool in the take-up direction by being input with rotation force in a second direction opposite to the first direction;
- a cut-off section that cuts off transmission of a rotation load in a pull-out direction along a rotation force transmission route from the spool to the second rotation force transmission mechanism to the first rotation force transmission mechanism when the rotation load in the pull-out direction becomes a predetermined value or greater;
- and a motor having a motor output shaft coupled with the end of the spool by the first rotation force transmission mechanism and the second rotation force transmission mechanism, the motor rotating the motor output shaft when driven, comprising the step of:
- selecting the cogging torque of the motor such that a product of a gear ratio of transmission of rotation force from the spool to the motor output shaft via the second rotation force transmission mechanism and a maximum value of the cogging torque becomes the predetermined value of the rotation load that causes the cut-off section to cut off transmission of the rotation load in the pull-out direction.
Dependencies are inferred from the claim text.