Patent ID: 6901895

Claim:
A camshaft rotational detection structure comprising: a camshaft having a cam sprocket mechanism attachment end; a cam thrust flange disposed on the camshaft near the cam sprocket mechanism attachment end, the cam thrust flange being configured and arranged to restrict axial movement of the camshaft; a detection target disposed on the cam thrust flange; a sensor configured and arranged to face opposite the detection target and to detect rotation of the camshaft; and a shaft bearing including a groove with the cam thrust flange being disposed in the groove in a freely sliding manner, and the shaft bearing being configured to axially support the camshaft to rotate freely in the groove, the cam thrust flange including an inner circumferential section disposed in the groove to define a first gap therebetween, and an outer circumferential section disposed in the groove to define a second gap therebetween that is larger than the first gap, the outer and inner circumferential sections being further configured and arranged to form a step on both lateral faces between the outer circumferential section and the inner circumferential section.