# Taper roller bearings

## Description

Single row taper roller bearings are detachable radial bearings. They have tapered raceways inside the inner and outer rings with tapered rollers placed in between. This makes them a good choice to carry radial and axial loads at the same time. Single row taper roller bearings carry axial forces in only one direction. It is always necessary to pair a bearing of this type with a second bearing, which guides the shaft in the opposite direction.

## Dimensions/standards

For single row taper roller bearings, the main dimensions are standardized according to ISO 355 (Metric taper roller bearings – dimensions and series designation), DIN 720 (Roller bearings – taper roller bearings) and DIN 616 (Roller bearings – boundary dimensions).

Inch bearings are standardized according to ANSI/ABMA-standard 19.2 (Tapered Roller Bearings – radial Inch Design).

## Tolerances

As the default, SLF manufactures taper roller bearings in standard tolerance (PN) according to DIN 620-2 (Roller bearing tolerances – tolerances for radial bearings) and ISO 492 (Radial bearings – dimensions and tolerances). However, we can also deliver these bearing types in other tolerances upon request.

## Bearing design types

Taper roller bearings are composed of an outer ring without shoulder and an inner ring with two shoulders of different heights. The roller cage assembly and the inner ring belong together. The higher shoulder of the inner ring carries the emerging axial force resulting from the rolling elements’ taper shape. The extended generatrices of the tapered rollers intersect with the prolonged inner and outer ring raceways at a point on the bearing axis, which makes possible excellent free-rolling and low-friction running. For technical reasons, one must always pair single row taper roller bearings with a mirror-reversed second taper roller bearing.

## Clearance

Clearance or preload is established when the bearing is paired with a second taper roller bearing during mounting/ installation.

## Cage

As the default, SLF -taper roller bearings are equipped with a window cage made of steel plate. We supply the bearing with other cage design types upon request.

## Working temperature

SLF-taper roller bearings with outer diameters up to 120 mm are standard stabilized in dimensions (suffix S0), meaning that they are subjected to heat treatment that makes them usable up to a working temperature of 150 °C. For outer diameters equal to and greater than 120 mm, the taper roller bearings are standard stabilized in dimensions (suffix S1), meaning that they are subjected to heat treatment that makes them usable up to a working temperature of 200 °C. As a rule, however, the maximum working temperature is not limited by the dimensional stability of the bearing rings and rolling elements; frequently it is limited by the lubricant/ grease. If you are uncertain or have specific questions regarding our bearings’ temperature limits, don’t hesitate to contact the SLF team.

## Greasing/lubrication & sealing

Taper roller bearings are produced without seals. Consequently, the bearing location must be sealed around/ on the surrounding components. The sealing must ensure that no moisture and/ or contaminants can enter the bearing and that no lubricant is lost.

Taper roller bearings are delivered ungreased but must be lubricated with oil or grease. Choose the lubricant according to the application.

## Dimensioning

### Dynamic equivalent load

\(\)

**a) for single bearings:**$$P = F_r$$ | for | $$\frac{F_a}{F_r} \leq{e}$$ |

$$P = 0,4 * F_r + Y * F_a$$ | for | $$\frac{F_a}{F_r} > e$$ |

**b) for bearing pairs in O or X arrangement:**$$P = F_r + 1,12 * Y * F_a$$ | for | $$\frac{F_a}{F_r} \leq{e}$$ |

$$P = 0,67 * F_r + 1,68 * Y * F_a$$ | for | $$\frac{F_a}{F_r} > e$$ |

P | dynamic equivalent load [kN] |

F_{r} | radial dynamic load [kN] |

F_{a} | axial dynamic load [kN] |

e, Y | factors [-] |

Factors e,Y are specified in the product table (Online-catalogue).

### Required minimal load

To avoid slippage between elements in contact, the taper roller bearings must be sufficiently loaded A minimal radial load in the order of magnitude of

\(\)$$P > \frac{C_{0r}}{60}$$

has been shown to be necessary.

In most cases, the radial load resulting from the weight of the components run on bearings combined with the external forces is higher alone than the minimal load required. Should this value not be met, contact an SLF application technician.

### Static equivalent load

\(\)

**a) for single bearings:**$$P_0 = F_{0r}$$ | for | $$\frac{F_{0a}}{F_{0r}} \leq \frac{1}{2 * Y_0}$$ |

$$P_0 = 0,5 * F_{0r} + Y_0 * F_{0a}$$ | for | $$\frac{F_{0a}}{F_{0r}} > \frac{1}{2 * Y_0}$$ |

**b) for bearing pairs in O or X arrangement:**$$P_0 = F_{0r} + 2 * Y_0 * F_{0a}$$ |

P_{0} | static equivalent load [kN] |

F_{0r} | radial static load [kN] |

F_{0a} | axial static load [kN] |

Y_{0} | factor [-] |

Values for Y_{0} are specified in the product table (Online-catalogue).

### Static load safety factor

For statically loaded taper roller bearings, always inspect the static load safety factor S_{0} in addition to the nominal lifetime L (L_{10h}).

\(\)$$S_{0} = \frac{C_0}{P_0}$$

S_{0} | static load safety factor [-] |

C_{0} | static load rating [kN] |

P_{0} | static equivalent load [kN] |

### Determination of the inner resultant axial force F_{a} for single bearings and bearing pairs in X and O arrangement

\(\)

Case | Load ratio | External axial forcee | Resultant axial force F_{a} | |

Bearing A | Bearing B | |||

1 | $$\frac{F_{rA}}{Y_A} \leq \frac{F_{rB}}{Y_B}$$ | $$K_a \geq 0$$ | $$F_{aA} = K_a + 0,47 * \frac{F_{rB}}{Y_B}$$ | F_{a} not taken into account in calculation. |

2 | $$\frac{F_{rA}}{Y_A} > \frac{F_{rB}}{Y_B}$$ | $$K_a > 0,47 * \left(\frac{F_{rA}}{Y_A} - \frac{F_{rB}}{Y_B}\right)$$ | $$F_{aA} = K_a + 0,47 * \frac{F_{rB}}{Y_B}$$ | F_{a} not taken into account in calculation. |

3 | $$K_a \leq 0,47 * \left(\frac{F_{rA}}{Y_A} - \frac{F_{rB}}{Y_B}\right)$$ | F_{a} not taken into account in calculation. | $$F_{aB} = 0,47 * \frac{F_{rA}}{Y_A} - K_a$$ |

K_{a} | external axial force applied to the shaft [kN] |

F_{rA} | radial dynamic load of bearing A [kN] |

F_{rB} | radial dynamic load of bearing B [kN] |

Y_{A}, Y_{B} | factors [-] |