Seatbelt retractor

A seatbelt retractor comprising:

• a housing;
• a take-up drum rotatably housed in the housing and configured to take-up and store a webbing;
• and
• a pretensioner mechanism configured to rotate the take-up drum in a webbing-take-up direction for taking up the webbing when vehicle collision occurs,
• wherein the pretensioner mechanism includes:
• a driven body configured to rotate co-axially with a rotation axis of the take-up drum when vehicle collision occurs;
• a driving device configured to rotate the driven body in the webbing-take-up direction;
• a holding plate formed in a substantially U-shape in cross section and arranged at an outer side of the housing with reference to the rotation axis of the take-up drum, the holding plate including a first shaft receiving hole which rotatably supports a boss portion shaped in a cylindrical shape and formed at a take-up drum side end of the driven body with reference to the rotation axis of the take-up drum and a second shaft receiving hole which rotatably supports a shaft portion formed on an outer end portion of the driven body with reference to the direction of rotational axis, the first shaft receiving hole and the second shaft receiving hole being formed at each side wall portion of the holding plate formed in the substantially U-shape;
• and
• a restricting member arranged at a take-up drum side surface of the side wall portion of the holding plate in which the first shaft receiving hole is formed and configured to restrict movement of the boss portion in a radial direction so that the boss portion projecting from the first shaft receiving hole is positioned co-axial with the take-up drum,
• wherein the boss portion faces an inner peripheral surface of the first shaft receiving hole and includes a first projecting portion projecting radially outward along an entire periphery at one edge thereof opposing the second shaft receiving hole with reference to the rotation axis,
• wherein the first shaft receiving hole includes:
• a first semicircular arc hole portion formed in a substantially semicircular arc shape at a part of the inner peripheral portion whereat the boss portion is pressed when the driven body is rotated and driven by the driving device;
• and
• a first enlarged hole portion formed so as to extend from the first semicircular arc hole portion and allow insertion of the first projecting portion therein, and
• wherein, position of the boss portion is restricted so as to be co-axial with the take-up drum by the restricting member, the first projecting portion projects radially outward over the first semicircular arc hole portion of the first shaft receiving hole so that the first projecting portion at least faces a peripheral edge portion of the first semicircular arc hole portion at a side opposing the second shaft receiving hole with reference to the rotation axis to avoid movement of a driven body in the rotation axis direction.