Patent ID: 7819765

Claim:
A tensioner supported on a fixed member for applying a tensile force to an endless torque transmitting member, comprising: a tension pulley engaged with the endless torque transmitting member; an arm supporting the tension pulley; a base member interposed between the arm and the fixed member; a pivot shaft penetrating the arm and inserted into the base member so as to allow the arm to rotate with respect to the base member; a torsion coil spring interposed between the base member and the arm so as to exert a rotational torque on the arm; a bolt penetrating the pivot shaft and screwed into the fixed member, the bolt having a bolt head engaged with a tip of the pivot shaft; and a relative displacement preventing mechanism which prevents a relative displacement between the base member and the pivot shaft when an axial force is transmitted from the bolt to the base member via the pivot shaft, wherein the relative displacement preventing mechanism comprises a large diameter part formed in the pivot shaft, which presses the base member against the fixed member in response to a tightening force of the bolt transmitted to the pivot shaft, the base member comprises a boss penetrated by the bolt, the large diameter part comprises a flange formed on the outer circumferential surface of the pivot shaft so as to be in contact with the boss from a direction along an axis of the pivot shaft, the boss has a through-hole penetrated by the bolt, the pivot shaft is fitted into the through-hole in a state where a tip of the pivot shaft does not contact the fixed member, and a contact portion between the base member and the pivot shaft overlaps a contact portion between the base member and the fixed member in an axial direction of the pivot shaft.