SEMRI Double row tapered roller bearings 78251D - 78551
Specifications
Series :78000
Cone Part Number : 78251D
Cup Part Number : 78551
Design Unit : Inch
Cage Material : Stamped Steel
Related Assembly Number(s)：78251D-90031
Dimensions
d - Bore : 2 1/2 in / 63.500 mm
D - Cup Outer Diameter : 5.5130 in / 140.030 mm
B - Double Cone Width : 2.5980 in / 65.989 mm
C - Cup Width : 0.9260 in / 23.520 mm
T - Bearing Width across Cups : 2.6020 in / 66.091 mm
Abutment and Fillet Dimensions
R - Cone Backface "To Clear" Radius1 : 0.09 in / 2.300mm
r - Cup Backface "To Clear" Radius2 : 0.090 in / 2.29mm
da - Cone Frontface Backing Diameter : 3.11 in / 79 mm
Db - Cup Backface Backing Diameter : 4.61 in / 117.09 mm
Ab - Cage-Cone Frontface Clearance : 0.08 in / 2 mm
Basic Load Ratings
C90 - Dynamic Radial Rating (One-Row, 90 million revolutions)3 :9970bf/44300N
C1 - Dynamic Radial Rating (Two-Row, 1 million revolutions)4: 66900 lbf /298000 N
C90(2) - Dynamic Radial Rating(Two-Row, 90 million revolutions)5 :17400lbf/ 77200N
Ca90 - Dynamic Thrust Rating (90 million revolutions)6 : 14800 lbf /65700 N
Factors
K - Factor7 : 0.67
e - ISO Factor8 : 0.87
Y1 - ISO Factor9 : 0.78
Y2 - ISO Factor10 : 1.16
G1 - Heat Generation Factor (Roller-Raceway) ：62.6
G2 - Heat Generation Factor (Rib-Roller End)： 19.1
Cg - Geometry Factor11 : 0.0884
