Patent ID: 8086340

Claim:
A hub posture detection method for, prior to mounting of a wheel on a hub of a vehicle conveyed along a vehicle conveyance line, detecting an inclination and center of the hub and orientations of hub bolts, comprising the steps of: imaginarily dividing a front surface of the hub into four equal parts, by use of perpendicularly-intersecting lines, to divide a pitch circle of the hub bolts into upper and lower and left and right divided pitch circle portions and specify a first horizontally-elongated rectangular area including the upper divided pitch circle portion and a second horizontally-elongated rectangular area including the lower divided pitch circle portion; measuring distances from a reference position to the first and second horizontally-elongated rectangular areas; calculating, on the basis of the distances measured by the measuring step, coordinates of respective centers of two of the hub bolts included within the first and second horizontally-elongated rectangular areas; calculating center coordinates of the hub on the basis of the coordinates of the centers of the two hub bolts; acquiring, from portions of the first and second horizontally-elongated rectangular areas where no hub bolt is included, coordinates of three points that define apexes of an imaginary triangle; calculating, on the basis of the coordinates of the three points, an inclination angle of the hub relative to a vertical plane extending along the vehicle conveyance line; and calculating an orientation of each of the hub bolts on the basis of the center coordinates of the hub and the coordinates of the center of the hub bolt.