| 摘要 |
PROBLEM TO BE SOLVED: To provide a gear mechanism to relax collision between gears and to provide a low-cost pretensioner to perform smooth winding of webbing during rapid deceleration of a vehicle. SOLUTION: A planetary gear 26 always engaged with a sun gear 24 rotated togetherwith a winding shaft 18 is revolved around the sun gear 24 as it is rotated during rapid deceleration of a vehicle. An internal gear 28 is positioned away from the planetary gear 26 during the normal state of a vehicle, and during rapid deceleration of a vehicle, the internal gear is moved in a direction, crossing the axis of the sun gear 24 at right angles, during rapid deceleration of a vehicle and engaged with the planetary gear 26 to rotate the planetary gear 26. During rapid deceleration of a vehicle, a drive force is exerted on a cam gear 32 and the internal gear 28 is slid and engaged with the planetary gear 26. Thus, since constitution is such that the internal gear 28 is slid and engaged with the planetary gear 26, collision of the internal gear 28 with the planetary gear 26 is relaxed and during rapid deceleration of a vehicle, webbing is smoothly wound by a low cost pretensioner. |
