Roller bearing with crowning
A roller bearing includes: an inner ring having an inner ring raceway; an outer ring having an outer ring raceway; and a plurality of rollers interposed between the inner ring raceway and an outer ring raceway, wherein a crowning is formed on at least one of the inner ring raceway, the outer ring raceway, and a roller rolling contact surface, wherein an optimal value of a drop amount of the crowning at an end of an effective length is determined, from a diameter of a roller and an effective length of the roller, and wherein drop amounts of the crowning at a plurality of positions in a bus-line direction of the crowning are within an allowable range set forth in a specific table.
1. A roller bearing comprising:
an inner ring having an inner ring raceway;
an outer ring having an outer ring raceway; and
a plurality of rollers interposed between the inner ring raceway and the outer ring raceway,
wherein a crowning is formed on at least one of the inner ring raceway, the outer ring raceway, and a roller rolling contact surface,
wherein a value zm[μm] of a drop amount of the crowning at an end of an effective length is determined from a diameter d[mm] of a roller and an effective length L[mm] of the roller using the following expression:
0.40( d+L )+0.66 ≦zm≦ 0.46( d+L )+1.03
wherein drop amounts of the crowning at a plurality of positions in a bus-line direction of the crowning are within an allowable range described in Table 1, with a center of the effective length of the roller being a point of origin, a bus-line direction position being made dimensionless by being divided by L/2, and the drop amount of the crowning being made dimensionless by being divided by zm.