Double row taper-roller bearing and method of assembling the same bearing

A method of assembling a double row taper-roller bearing comprising:

• an outer ring having first and second track surfaces which are formed along an inner peripheral surface thereof and respectively configure some proportions of tapered shapes opened opposite to each other outwards in the axial direction;
• a first inner ring member extending over an entire length of said outer ring in the axial direction and having a first outer track surface formed along an outer periphery thereof and configuring a part of a tapered shape, facing to said first track surface of said outer ring and opened in the same direction, a portion of the first inner ring member facing to said second track surface of said outer ring being formed as a fitting surface;
• a second inner ring member having a second outer track surface formed along an outer periphery thereof, facing to said second track surface of said outer ring and configuring a part of a tapered shape opened in the same direction, the second inner ring member being fixedly fitted on the fitting surface of said first inner ring member;
• a first roller row including a plurality of taper-rollers interposed between said first track surface of said outer ring and said first outer track surface of said first inner ring member, and rolling while being kept in contact with said track surfaces, and a first holder for holding said first taper-rollers;
• and
• a second roller row including a plurality of taper-rollers interposed between said second track surface of said outer ring and said second outer track surface of said second inner ring member, and rolling while being kept in contact with said track surfaces, and a second holder for holding said second taper-rollers,
• said method comprising, after assembling said outer ring, said first roller row, said first inner ring member and said second roller row, the steps of:
• measuring a tentative axial gap, with a tentative bearing body being assembled by inserting, into an air space for inserting said second inner ring member formed between the fitting surface of said first inner ring member and said second roller row, a master for said second inner ring member having the known dimensions serving as a positive axial gap with respect to this air space;
• and
• calculating dimensions of said second inner ring member, from which a desired negative axial gap is obtained based on the measured tentative axial gap, and selecting and assembling said desired second inner ring member on the basis of a result of the calculation.

A wheel support structure including a fixed member to be fixed to a knuckle of a suspension system, and a hub for fitting a wheel, said structure comprising:

• an outer ring integral with said fixed member and having first and second track surfaces which are formed along an inner peripheral surface thereof and respectively configure some proportions of tapered shapes opened opposite to each other outwards in the axial direction;
• a first inner ring member integral with said hub, extending over an entire length of said outer ring in the axial direction and having a first outer track surface formed along an outer periphery thereof and configuring a part of a tapered shape, facing to said first track surface of said outer ring and opened in the same direction, a portion of the first inner ring member facing to said second track surface of said outer ring being formed as a fitting surface
• a second inner ring member having a second outer track surface formed along an outer periphery thereof facing to said second track surface of said outer ring and configuring a part of a tapered shape opened in the same direction, the second inner ring member being fixedly fitted on the fitting surface of said first inner ring member;
• a first roller row including a plurality of taper-rollers interposed between said first track surface of said outer ring and said first outer track surface of said first inner ring member, and rolling while being kept in contact with said track surfaces, and a first holder for holding said first taper-rollers;
• and
• a second roller row including a plurality of taper-rollers interposed between said second track surface of said outer ring and said second outer track surface of said second inner ring member, and rolling while being kept in contact with said track surfaces, and a second holder for holding said second taper-rollers.

A method of assembling a wheel support structure which includes a fixed member to be fixed to a knuckle of a suspension system, and a hub for fitting a wheel, said structure comprising:

• an outer ring integral with said fixed member and having first and second track surfaces which are formed along an inner peripheral surface thereof and respectively configure some proportions of tapered shapes opened opposite to each other outwards in the axial direction;
• a first inner ring member integral with said hub, extending over an entire length of said outer ring in the axial direction and having a first outer track surface formed along an outer periphery thereof and configuring a part of a tapered shape facing to said first track surface of said outer ring and opened in the same direction, a portion of the first inner ring member facing to said second track surface of said outer ring being formed as a fitting surface
• a second inner ring member having a second outer track surface formed along an outer periphery thereof facing to said second track surface of said outer ring, and configuring a part of a tapered shape opened in the same direction, the second inner ring member being fixedly fitted on the fitting surface of said first inner ring member;
• a first roller row including a plurality of taper-rollers interposed between said first track surface of said outer ring and said first outer track surface of said first inner ring member, and rolling while being kept in contact with said track surfaces, and a first holder for holding said first taper-rollers;
• and
• a second roller row including a plurality of taper-rollers interposed between said second track surface of said outer ring and said second outer track surface of said second inner ring member, and rolling while being kept in contact with said track surfaces, and a second holder for holding said second taper-rollers,
• said method comprising, after assembling said outer ring, said first roller row, said first inner ring member and said second roller row, the steps of:
• measuring a tentative axial gap, with a tentative bearing body being assembled by inserting, into an air space for inserting said second inner ring member formed between the fitting surface of said first inner ring member and said second roller row, a master for said second inner ring member having the known dimensions serving as a positive axial gap with respect to this air space;
• and
• calculating dimensions of said second inner ring member, from which a desired negative axial gap is obtained based on the measured tentative axial gap, and selecting and assembling said desired second inner ring member on the basis of a result of the calculation.

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 taking a configuration of tapered convex surface and directly formed along an outer peripheral surface of an intermediate portion thereof, for configuring said taper-roller bearing of a first row, and a small-diameter stepped portion provided on an outer peripheral surface of the other side end thereof,
• said inner ring member includes a second inner ring track, taking a configuration of tapered convex surface and formed along an outer peripheral surface thereof, for configuring said taper-roller bearing of a second row, 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 taking a configuration of tapered concave surface and formed along an inner peripheral surface thereof, for configuring said taper-roller 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 in a state of so being held by said first holder as to be rollable, and said remaining taper-rollers are disposed between said second inner ring track and said second outer ring track in a state of being so held by said second holder as to be rollable,
• said first holder prevents said respective taper-rollers from coming off inwards in the diametrical direction in a state of 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 in a state of holding said remaining taper-rollers among said plurality of taper-rollers.