| 摘要 |
PURPOSE: To increase winding quantity of a seat belt by engaging a clutch outer wheel with a planetary gear so as to make the rotor rotatable concentrically with a winding shaft and rotating the rotor by gas pressure of a gas pressure generator. CONSTITUTION: A pretensioner 12 provided with a drive means which rotates a winding shaft in the direction removing seat belt slack is arranged on one 2a of base side walls of a retractor base 2. This pretensioner 12 is provided with a clutch outer ring 6 which is a rotation drive member for intermittently transmitting torque to the winding shaft via a clutch mechanism 13, around the winding shaft. The clutch outer ring 6 and a planetary gear 15, which is an acceleration gear transmission device, are made to engaged with each other and the planetary gear 15 and internal teeth 4b formed around the internal circumferencial part of a rotor 4 are made to engage with each other. Gas pressure from a gas generator 1 is applied on a receive face of a rotor vane part 4a of the rotor 4 so as to rotate the rotor 4. The winding quantity of the seat belt can be thus increased. |
