Patent ID: 7444970
Filing Date: 2008-11-04
Classification: F01L

Abstract:
1. A valve timing controlling apparatus comprising: a first rotary body rotatable with a cam shaft of an internal combustion engine; a second rotary body rotatable with a crank shaft and rotatable relative to the first rotary body; a controlling means for varying relative rotational phase between the first rotary body and the second rotary body; and a torsion coil spring for urging the first rotary body relative to the second rotary body in a phase advancing direction; wherein said torsion coil spring includes a pair of retaining portions to be retained respectively to said first rotary body and said second rotary body and a coil portion disposed between said pair of retaining portions; wherein said coil portion includes a pair of holding areas extending continuously from said respective retaining portions and capable of fixing said coil portion in position relative to respective peripheral faces of said first rotary body and said second rotary body formed coaxially with a rotational axis of said first and second rotary bodies and includes also a torque generating area disposed between said pair of holding areas, said holding areas and said torque generating area having different coiling diameters from each other; and wherein one of said pair of retaining portions of the torsion coil spring is retained to an outer peripheral face of one of the first and second rotary bodies which is disposed on the inner side of the torsion coil spring; the other retaining portion is retained to an inner peripheral face of the other one of the first and second rotary bodies which is disposed on the outer side of the torsion coil spring; and said torque generating area has a coiling diameter greater than the holding area extending continuously from said one retaining portion retained to said outer peripheral face and smaller than the other holding area extending continuously from the other retaining portion retained to said inner peripheral face.