| CPC B60R 22/4676 (2013.01) [B60R 22/343 (2013.01); B60R 2022/287 (2013.01); B60R 22/4628 (2013.01)] | 5 Claims |
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1. A seat belt retractor comprising:
a housing including a pair of side walls facing each other;
a winding drum configured to wind up a webbing, the winding drum being housed between the pair of side walls so as to be rotatable in a winding direction and a pull-out direction of the webbing, the winding drum having a center hole opened on at least a first end surface of the winding drum;
a locking base disposed to face the first end surface of the winding drum, the locking base being prevented from being rotated in the pull-out direction, in an emergency of a vehicle, a male screw being formed on an outer circumferential surface of a shaft portion, of the locking base, coaxial with the winding drum;
an impact energy absorbing member including one end side coupled to the winding drum and the other end side coupled to the locking base, the impact energy absorbing member connecting the winding drum and the locking base so as to be integrally rotatable, in a normal state, and the impact energy absorbing member being configured to be plastically deformed in a case where a pull-out force of the webbing exceeds a predetermined value in a state where the locking base is prevented from being rotated in the pull-out direction, so as to absorb impact energy while allowing relative rotation between the winding drum and the locking base;
at least one impact energy absorbing wire housed in at least one slot that is provided in the winding drum so as to form an opening in the first end surface of the winding drum, a head portion of the at least one impact energy absorbing wire that protrudes from the opening of the slot being attached to the locking base, the at least one impact energy absorbing wire being configured to be pulled out from the opening while being plastically deformed in a case where the winding drum and the locking base are relatively rotated, so as to absorb the impact energy; and
a stopper member being held in the center hole of the winding drum without being rotatable relative to the winding drum and so as to be movable in an axial direction of the winding drum, the stopper member being screwed onto the male screw of the locking base, and the stopper member being configured to define an allowable amount of relative rotation between the winding drum and the locking base in a case where the impact energy absorbing member absorbs the impact energy,
wherein the locking base includes three or more holding portions that are separated from each other in a circumferential direction around a rotation center of the winding drum,
the number of the holding portions is larger than the number of slots, and
the head portion of the at least one impact energy absorbing wire is attached to at least one of the holding portions.
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