External dimensions（mm)
| d | 45 |
| D | 73 |
| T | 20 |
| T3 | 21.3 |
| T4 | 24 |
γ
(minimum) | 1 |
Bearing code
Flat bottomed seat
loop type | 51209 |
Heart regulating ball
Face seat | 53209 |
Spherical seat
loop type | 53209U |
size（mm)
| d1 | 73 |
| d1 | 47 |
| D2 | 60 |
| d3 | 78 |
| B | 7.5 |
| A | 26 |
| R | 56 |
Installation size(mm)
Da
(minimum） | 62 |
da
(maximum） | 56 |
γa
(maximum) | 1 |
weight(kg)(refer to)
Flat bottomed seat
loop type | 0.31 |
Heart regulating ball
Facial shape | 0.333 |
Spherical seat
loop type | 0.419 |
describe
51209 Bearings are mainly used in industries such as construction machinery, machine tools, automobiles, metallurgy, mining, petroleum, machinery, electricity, and railways
