Seat belt retractor and seat belt apparatus

摘要

In order to provide a seat belt retractor (1) and a seat belt apparatus (100) capable of avoiding abrupt change in EA load so as to optimize the EA load, a ring (19) of the retractor (1) has a first reducing radius portion (32) of which radius gradually reduces toward the downstream in a winding direction of a plate member (20) onto the ring (19), and a second reducing radius portion (33) which is located on the downstream side in the winding direction relative to the first reducing radius portion (32) and where the reducing degree of the radius is greater than that of the first reducing radius portion (32). In addition, a large-diameter cylindrical portion (4b) of a spool (4) has a convexity (30) which is formed on the inner periphery of the large-diameter cylindrical portion (4b) and of which contact face (30a) comes in contact with the end of the other end portion (20b) of the plate member (20) so as to stop the plate member (20) and a concavity (35) which is formed in the inner periphery of the large-diameter cylindrical portion (4b) and is located at the side of the contact face (30a) of the convexity (30).