Patent ID: 8540178

Claim:
A seatbelt retractor comprising: a take-up drum for winding a webbing which is rotatably housed in a housing; and a pretensioner mechanism portion which takes up the webbing at time of vehicle collision, the pretensioner mechanism portion including: a pinion gear body which rotates co-axially to a rotational axis of the take-up drum at the time of vehicle collision a driving unit which drives the pinion gear body; a first rotation body which is mounted and fixed to one end of the pinion gear body co-axially, the first rotation body substantially having an annular shape; a second rotation body which is mounted to the one end of the pinion gear body so as to meet with an inner surface of the first rotation body co-axially and keeps motionless state when the pinion gear body is in initial rotation state, the second rotation body substantially having an annular shape; and a clutch pawl which is rotatably supported by at least one rotation body, either the first rotation body or the second rotation body, placed between the first rotation body and the second rotation body so as to be held inside of the outer peripheral portions of the first rotation body and the second rotation body, and projects in an outward radial direction so as to exceed the outer peripheral portions of the first rotation body and the second rotation body in response to relative rotation of the first rotation body with respect to the second rotation body so as to get engaged with the take-up drum, wherein: the one rotation body is placed to face the other rotation body which includes a guiding portion to lead the clutch pawl in an outward radial direction by pushing and moving the clutch pawl along relative rotation of the one rotation body, the second rotation body includes a positioning projection which is arranged so as to protrude toward the housing or toward a base plate fixed to the housing and becomes engaged with either the housing or the base plate, and the positioning projection becomes fractured when the clutch pawl presses the guiding portion in response to rotation of the first rotation body so as to cause the second rotation body and the first rotation body to rotate integrally.