Double row taper-roller bearing

A hub unit for an automobile, comprising:

• a hub body;
• an inner ring member fixedly fitted on an outer portion of said hub body;
• an outer ring disposed along circumferences of said hub body and of said inner ring member;
• a plurality of taper-rollers provided between outer peripheral surfaces of said hub body and of said inner ring member, and an inner peripheral surface of said outer ring;
• a first seal ring for hermetically sealing between an inner peripheral surface of one side end of said outer ring and an outer peripheral surface of an intermediate portion of said hub body;
• and
• a second seal ring for hermetically sealing between an inner peripheral surface of the other side end of said outer ring and an outer peripheral surface of a side end of said inner ring member,
• wherein said hub body includes a flange provided along an outer peripheral surface of one side end thereof for supporting a wheel, a first inner ring track configured as a tapered convex surface and directly formed along an outer peripheral surface of an intermediate portion of said hub body for configuring a first row of said taper-roller bearing, and a small-diameter stepped portion provided on an outer peripheral surface of the other side end of said hub body,
• said inner ring member includes a second inner ring track configured as a tapered convex surface and formed along an outer peripheral surface thereof for configuring a second row of said taper-roller bearing, and is fixedly fitted to an outer portion of said small-diameter stepped portion,
• said outer ring includes first and second outer ring tracks, each configured as a tapered concave surface and formed along an inner peripheral surface thereof for configuring said taperroller bearings of the first and second rows,
• some of said plurality of taper-rollers are disposed between said first inner ring track and said first outer ring track and being held by a first holder as to be rollable, and remaining taper-rollers are disposed between said second inner ring track and said second outer ring track and being held by a second holder as to be rollable,
• said first holder prevents said respective taper-rollers from coming off inwards in the diametrical direction by holding some of said plurality of taper-rollers, and
• said second holder prevents said respective taper-rollers from coming off outwards in the diametrical direction by holding on a periphery of said second inner ring track said remaining taper-rollers among said plurality of taper-rollers.