Wheel bearing device

A wheel bearing device comprising:

• an outer member having double-row raceway surfaces in an inner circumference, an inner member including a hub wheel mounted on a wheel and having double-row raceway surfaces which opposed to the raceway surfaces of the outer member in an outer circumference, and double-row rolling elements intervening between the raceway surfaces of the outer member and the inner member;
• and a constant velocity universal joint having an outer joint member, in which projections extending in an axial direction and provided in any one of a shaft portion of the outer joint member and a hole portion of the hub wheel are press-fitted into the other to form recesses by the projections in the other, by which a recess-projection fitting structure where an entire area of fitting sites of the projections and the recesses is brought into close contact is constructed, and a bolt hole is provided in the shaft portion of the outer joint member, and a bolt member screwed into the bolt hole fastens the hub wheel and the outer joint member, while applying a drawing force in the axial direction in a state where the bolt member is detached permits separation of the recess-projection fitting structure,
• wherein as the bolt member, if a seating surface outer diameter thereof is d1 and a shaft diameter thereof is d2, the bolt member satisfying a relational expression of 2.3≦(d1/d2)2≦4.9 is used.