Autotensioner

摘要

An autotensioner comprising: a support arm (2) having one end supported and the other end biased in a predetermined direction; a tension pulley (3) supported by the other end of the support arm; and a friction member (5) held in sliding contact with the support arm for applying a rocking resistance to the support arm, and having a Rockwell hardness ÄHRRÜ of 30 to 40 in at least its portion in sliding contact with the support arm.