| 摘要 |
PURPOSE: To provide a sheet belt pretensioner and an air bag driving device of which operations are stable for a long period of time, have a high reliability and cost-effective one. CONSTITUTION: A vehicle-sensitive inertia mass 12 is pivotally installed within a housing 10. A strike piece 18 pivotally arranged within the housing and applied with a spring load toward a firing pin is abutted against an inertia mass can surface 26 through a roller 24 attached to the strike piece in such a way that it may easily be moved. A contour of the cam surface, a motion path of the roller at the time of pivoting motion of the strike piece applied with a spring load and a moving direction of the inertia mass are adapted to each other under a state in which a triggering criteria of an electronic trigger circuit for integrating the deceleration values above a predetermined threshold value with respect to time are simulated. By employing rolling bearings 14, 20 and 22 and by the hermetic sealing of the housing, the triggering parameters remain unchanged for a long time. |
