Variable valve timing device and method of assembling same

A valve timing varying device that varies an opening and closing timing of an intake valve or an exhaust valve driven so as to open and close via a camshaft by controlling an oil pressure in an advanced angle chamber and a retarded angle chamber, the valve timing varying device comprising:

• a housing rotor rotated on a rotation axis of the camshaft in synchronism with rotation of a crankshaft;
• a vane rotor rotated integrally with the camshaft and accommodated in an accommodating chamber of the housing rotor so as to relatively rotate within a predetermined angle range to divide the accommodating chamber into the advanced angle chamber and the retarded angle chamber;
• and
• a torsional coiled urging spring for urging the vane rotor toward one rotation direction relative to the housing rotor,
• wherein the housing rotor is composed of a bottomed cylindrical front side housing member having an opening though which a bolt for fastening the vane rotor to the camshaft is inserted from a front side, and a rear side housing member joined with the front side housing member,
• the urging spring has a coil part, a first end provided outside in a radial direction with respect to the coil part, and a second end provided inside in the radial direction with respect to the coil part,
• the front side housing member has a first latching concave part for receiving and latching the first end of the urging spring on an inside wall face facing the vane rotor, and
• the vane rotor has an accommodating concave part for receiving at least a part of the coil part of the urging spring on a front end side facing an inside wall face of the front side housing member, and a second latching concave part for receiving and latching the second end of the urging spring in an area facing the opening on the front side end, the second latching concave part being visible though the opening.