Pretensioner, retractor, and seat belt device

A retractor comprising:

• a spool for winding a webbing that restrains an occupant;
• and
• a pretensioner for winding the webbing and eliminating slack in an emergency, wherein
• the pretensioner comprising a ring gear to which a spool is rotatably disposed;
• and
• power transmission units for transmitting power to the ring gear in an emergency, wherein
• the power transmission units each comprise a rod-shaped power transmission member for transmitting power to the ring gear while being plastically deformed, a tip reinforcing member disposed on a tip side of the power transmission member, a pipe for containing the power transmission member, and a gas generator disposed at an end of the pipe,
• the tip reinforcing member is formed such that a length with respect to an axial direction of the power transmission member is smaller than a pitch of the ring gear.

A seat belt device comprising:

• a webbing for restraining an occupant;
• a retractor for winding the webbing;
• a belt anchor for fixing the webbing on a vehicle body side;
• a buckle disposed on a side surface of the seat;
• and
• a tongue disposed in the webbing, wherein
• the retractor comprising a spool for winding the webbing;
• and
• a pretensioner for winding the webbing and eliminating slack in an emergency, wherein
• the pretensioner comprising a ring gear to which a spool is rotatably disposed;
• and
• power transmission units for transmitting power to the ring gear in an emergency, wherein
• the power transmission units each comprise a rod-shaped power transmission member for transmitting power to the ring gear while being plastically deformed, a tip reinforcing member disposed on a tip side of the power transmission member, a pipe for containing the power transmission member, and a gas generator disposed at an end of the pipe,
• the tip reinforcing member has higher strength than the power transmission member, and
• the tip reinforcing member is formed such that a length with respect to an axial direction of the power transmission member is smaller than a pitch of the ring gear.