Composite structure and valve timing adjustment device having the same

A composite structure comprising:

• a countersunk hole component having a countersunk hole shaped in a tapered hole and a plate side fitting hole adjacent to a small diameter side of the countersunk hole;
• a screw hole component having a screw hole shaped in a female thread and a screw side fitting hole located opposite from the plate side fitting hole through the screw hole;
• and
• a plate screw component including a seat part having a tapered surface to be seated on the countersunk hole, a screw part shaped in a male thread and engaged with the screw hole, and a plate side fitting part and a screw side fitting part respectively fitted with the plate side fitting hole and the screw side fitting hole to be in alignment with each other, wherein
• a difference δϕa in diameter between the plate side fitting hole and the plate side fitting part, a difference δϕb in diameter between the screw side fitting hole and the screw side fitting part, and an effective difference δϕc in diameter between the screw hole and the screw part satisfy a dimensional relation of δϕa<δϕc and δϕb<δϕc.