Patent ID: 8166936

Claim:
A valve timing adjusting apparatus for adjusting a valve timing of a valve that is opened and closed by a camshaft based on a torque transmitted from the crankshaft in an internal combustion engine, the valve timing adjusting apparatus comprising: a housing that is rotatable synchronously with the crankshaft, wherein the housing has a stopper; a vane rotor that integrally includes a rotational shaft and a vane, wherein: the rotational shaft is rotatable synchronously with the camshaft; the vane defines an advance chamber and a retard chamber in the housing; the advance chamber and the retard chamber are arranged one after another in a rotational direction of the vane rotor; and supply of working fluid to the retard chamber or the advance chamber generates a shift of a rotational phase of the vane rotor relative to the housing in a retard direction or in an advance direction, respectively; and a spiral spring that has a most radially inward part engaged with the rotational shaft in a state that the most radially inward part is wound around the rotational shaft, wherein: the rotational phase has an intermediate position defined between a full retard position and a full advance position of the rotational phase; the spiral spring has a radially outward segment that is located at a position radially outward of the most radially inward part; and when the rotational phase is in a range on a retard side of the intermediate position or on an advance side of the intermediate position, the radially outward segment of the spiral spring is engaged with the stopper of the housing such that the spiral spring urges the vane rotor in the advance direction or in the retard direction relative to the housing, respectively, wherein the stopper of the housing is a first stopper, wherein the vane rotor has a second stopper, wherein, when the rotational phase is in the range on the retard side of the intermediate position, the radially outward segment of the spiral spring positioned radially outward of the most radially inward part is engaged with the first stopper, and wherein, when the rotational phase is in the range on the advance side of the intermediate position, the radially outward segment of the spiral spring positioned radially outward of the most radially inward part is engaged with the second stopper.