Patent ID: 8011337

Claim:
A valve timing adjusting apparatus provided to a driving force transmission system that transmits driving force from a drive shaft of an internal combustion engine to a driven shaft that opens and closes at least one of an intake valve and an exhaust valve, wherein the valve timing adjusting apparatus adjusts timing of opening and closing the at least one of the intake and exhaust valves, the valve timing adjusting apparatus comprising: a first rotor that is rotatable synchronously with the drive shaft; a second rotor that is rotatable synchronously with the driven shaft, wherein: the second rotor and the first rotor define therebetween an advance chamber and a retard chamber that are arranged one after another in a rotational direction; the second rotor drives the driven shaft relative to the drive shaft in an advance direction when working fluid is supplied to the advance chamber; and the second rotor drives the driven shaft relative to the drive shaft in a retard direction when working fluid is supplied to the retard chamber; and a bias mechanism that is provided to one of the first and second rotors, wherein: the bias mechanism includes a resilient member and a projection portion; the projection portion is rotatable together with the one of the first and second rotors; the projection portion is rotatable relative to the other one of the first and second rotors and contacts a contact part of the other one of the first and second rotors; and the resilient member and the projection portion are arranged such that restoring force of the resilient member is applied to the other one of the first and second rotors through the projection portion, wherein: the contact part of the other one of the first and second rotors includes an inclination portion that is opposed to the projection portion; the inclination portion is configured to increase and decrease restoring force of the resilient member; the bias mechanism includes a support shaft portion receiving therein the resilient member and supporting the first and second rotors from inner sides of the first and second rotors; the one of the first and second rotors includes a first support hole that opens to one end of the support shaft portion; the first support hole receives therein the resilient member; the other one of the first and second rotors includes a second support hole that opens to the other end of the support shaft portion, the other one of the first and second rotors receives the support shaft portion such that the support shaft portion is slidable along an inner periphery of the second support hole; and the contact part is provided at a bottom portion of the second support hole.