Bearing device for vehicle wheel

A bearing device for vehicle wheel comprising:

• an outer member having double-row outer rolling surfaces formed on an inner periphery;
• an inner member having double-row inner rolling surfaces formed on an outer periphery;
• a plurality of rolling elements rollably interposed between each of the outer rolling surfaces of the outer member and a corresponding one of the inner rolling surfaces of the inner member;
• an inner-side undercut part provided at a portion where the inner rolling surface formed on an inner side of the inner member and an inner-side flange surface of the inner rolling surface intersect;
• an outer-side undercut part provided at a portion where the inner rolling surface formed on an outer side of the inner member and an outer-side flange surface of the inner rolling surface intersect;
• and
• a vehicle wheel installation flange provided adjacent to the inner rolling surface formed on the outer side of the inner member,
• wherein a radius of curvature of the inner-side undercut part defined as Ri and a radius of curvature of the outer-side undercut part defined as Ro satisfy a relation of Ri<Ro.