| 摘要 |
A seat belt device has a gas generator (11) for generating a high pressure gas when the vehicle is in emergency, a cylinder (17) for conducting the high pressure gas from the gas generator, a piston (20) received movably within the cylinder and pressed and moved by the high pressure gas, and a drive unit for rotating a winding shaft (4) of a seat belt retractor in a direction of removing the slack of a belt, using the movement of the piston, wherein the pretensioner is employed with an energy absorbing mechanism, for reversely rotating the winding shaft if a tension acting on the belt exceeds a predetermined value after removing the slack of the belt. For facilitating this reverse rotation, a venting mechanism (22a) having a gas passageway for exhausting the high pressure gas from a space filled with the high pressure gas to the outside of the space is provided, wherein at least a part of the gas passageway is expanded as the high pressure gas is exhausted. <IMAGE> |
