METHOD FOR MANUFACTURING WHEEL SUPPORTING ROLLER BEARING UNIT, AND METHOD FOR TESTING DOUBLE-RACE ROLLER BEARING UNIT

摘要

Provided is a wheel supporting roller bearing unit, which is different in the pitch circle diameters of balls (6a and 6b) between an outer race and an inner race but which is identical in contact angles (a_OUT and a_IN) when the balls (6a and 6b) of the two races are completed. The initial contact angles (ß_OUT and ß_IN) are smaller than those predetermined contact angles (a_OUT and a_IN). The degree "a_IN - ß_IN", at which the initial contact angle (ß_IN) of the balls (6b and 6b) of the inner race is made smaller than the predetermined contact angle (a_IN) of the balls (6b and 6b), is made larger ("a_IN - ß_IN" > "a_OUT - ß_OUT") than the degree "a_OUT - ß_OUT", at which the initial contact angle (ß_OUT) of the balls (6a and 6a) of the outer race is made smaller than the predetermined contact angle (a_OUT) of the balls (6a and 6a). In this constitution, the predetermined contact angles (a_OUT and a_IN) are given to the balls (6a and 6b) of the two races in the completed state so that the pre-pressure and contact angle of the balls (6a and 6b) of the two races are made proper.