Tapered roller bearing resin cage and tapered roller bearing

A tapered roller bearing comprising:

• an outer ring having an outer ring raceway surface on an inner peripheral surface;
• an inner ring having an inner ring raceway surface on an outer peripheral surface, and a small flange and a large flange on both sides of the inner ring raceway surface in an axial direction;
• a plurality of tapered rollers rollably arranged between the outer ring raceway surface and the inner ring raceway surface;
• and
• a resin cage,
• wherein the resin cage comprises a small diameter annular portion, a large diameter annular portion, and a plurality of bar portions arranged at intervals in a circumferential direction to connect the annular portions, pockets for holding the tapered rollers being formed between the annular portions and adjacent ones of the bar portions,
• wherein each of the bar portions comprises a pair of circumferentially-directed side surfaces, each comprising a roller guide surface, and an inner-side inner peripheral surface, a circumferential width of the inner-side inner peripheral surface being smaller on a side of the large diameter annular portion than a circumferential width on a side of the small diameter annular portion,
• wherein each of the pockets has a roller retaining region in which a radially outer side pocket width and a radially inner side pocket width between the opposed circumferentially-directed side surfaces of the adjacent bar portions are smaller than a diameter of each tapered roller,
• wherein the roller guide surface is configured as a flat surface,
• wherein each of the circumferentially-directed side surfaces comprises a curved surface disposed radially inward of the roller guide surface,
• wherein a circumferential gap between the each tapered roller and a boundary of the curved surface and the inner-side inner peripheral surface at an edge of the boundary on a large diameter side is equal to or larger than the circumferential gap at a remaining part of the boundary on a small diameter side, so as to allow each tapered roller to shift radially inward when attaching each tapered roller to the pocket in the axial direction from the side of the large diameter annular portion, and
• wherein the large diameter annular portion is formed with recessed portions on an inner peripheral surface and centrally located between the adjacent ones of the bar portions, so as to prevent an interference of each tapered roller with the large diameter annular portion when attaching each tapered roller to the pocket in the axial direction from the side of the large diameter annular portion.