C-shaped ring detector used for shaft of electric power steering system

The utility model discloses a C-shaped ring detector used for the shaft of an electric power steering system, which comprises a cylinder capable of being sheathed on a round shaft to rotate; the bottom of the cylinder is fixedly provided with a sliding block the bottom surface of which is smooth; after an outer column jacket assembly of an electric power steering system of a motor vehicle is completely mounted by blocking a shaft through a C-shaped ring; if the C-shaped ring is not completely blocked in a mounting position on the shaft, the annular surface of the C-shaped ring can be deformed and distorted; if the C-shaped ring is completely blocked in the mounting position on the shaft, then the annular surface of the C-shaped ring is a plane; the cylinder is sheathed into the shaft to lead the bottom surface of the sliding block to butt against the annular surface of the C-shaped ring; and if the cylinder rotates by a circle and the sliding block slides on the annular ring of the C-shaped ring without block