| 摘要 |
<p>In the present invention, a retractor for a seat belt achieves an improvement in the strength of a rack of a piston against impact when the rack first meshes with a pinion, with the least possible effect on the build of a pre-tensioner unit. The retractor for a seat belt is provided with a take-up drum for taking up a webbing and a pre-tensioner unit for rotating the take-up drum in the webbing take-up direction. The pre-tensioner unit includes: a pinion gear capable of rotating in conjunction with the take-up drum; a piston for rotating the take-up drum in the take-up direction via the pinion gear, the piston having a rack that can mesh with the pinion gear; a pipe cylinder for movably housing the piston; and a gas generation unit for driving the piston. Distal-end rack teeth provided to a distal end of the piston are set so that the full-tooth depth is smaller than that of proximal-end rack teeth.</p> |
