Calculation of permissible axial load – cylindrical rollers with toroidal crowned roller ends
For bearings with toroidal roller ends, the permissible axial loads are 50% higher ➤ Equation.
Permissible axial load – bearings of TB design
Calculation of maximum permissible axial load
The maximum permissible axial load Fa max ➤ Equation is calculated from the rib strength and security against wear. This must not be exceeded, even if Fa per gives higher values ➤ Equation.
Maximum axial load – bearings of standard and TB design
Permissible axial load
Axial load under shaft deflection
Permissible axial load under shaft deflection of up to 2′
Under considerable shaft deflection, the shaft shoulder presses against the inner ring rib. In combination with the active axial load, this can lead to high alternating loading of the inner ring ribs. Under a shaft deflection of up to 2′, the permissible axial load can be estimated ➤ Equation.
If more severe tilting is present, a separate strength analysis is required. In this case, please contact Schaeffler.
Axial load under misalignment
Permissible axial load under misalignment
Angular deviations are misalignments between the inner and outer ring
The possible misalignment between the inner ring and outer ring is influenced by the internal bearing construction, the operating clearance, the forces acting on the bearing etc. Due to these complex relationships, it is not possible to give generally valid absolute values here. However, misalignments (angular deviations) between the inner ring and outer ring always have an effect on the running noise and the operating life of the bearings.
The permissible guide values at which, based on experience, there is no significant reduction in operating life are as follows:
- 4 ′ for series SL1818
- 3 ′ for series SL1923, SL1822, SL1829, SL1830
Scope of values
The values apply to:
- bearing arrangements with static misalignment (consistent position of the shaft and housing axis)
- bearings that are not required to perform an axial guidance function
- bearings subjected to small loads (with C0r/P ≧ 5)
Checking by means of the calculation program BEARINX is recommended in all cases. If there is any uncertainty regarding possible misalignment, please consult Schaeffler.
Oil or grease lubrication is possible
The cylindrical roller bearings are not greased. They must be lubricated with oil or grease.
If there is any uncertainty regarding the suitability of the selected lubricant for the application, please consult Schaeffler or the lubricant manufacturer.
Observe oil change intervals
Aged oil and additives in the oil can impair the operating life of plastics at high temperatures. As a result, stipulated oil change intervals must be strictly observed.
Providing additional seals in the adjacent construction
The bearings are not sealed; i. e. sealing of the bearing position must be carried out in the adjacent construction. This must reliably prevent:
- moisture and contaminants from entering the bearing
- the egress of lubricant from the bearing
Limiting speeds and reference speeds in the product tables
The product tables give two speeds for most bearings:
- the kinematic limiting speed nG
- the thermal speed rating nϑr
Lower speed capacity than bearings with cage
Due to the kinematic conditions, however, bearings without cage do not achieve the high speeds that are possible when using bearings with cage.
The limiting speed nG is the kinematically permissible speed of the bearing. Even under favourable mounting and operating conditions, this value should not be exceeded without prior consultation with Schaeffler ➤ link.
nϑr is used to calculate nϑ
The thermal speed rating nϑr is not an application-oriented speed limit, but is a calculated ancillary value for determining the thermally safe operating speed nϑ ➤ link.
The Schaeffler Noise Index (SGI) has been developed as a new feature for comparing the noise level of different bearing types and series. As a result, a noise evaluation of rolling bearings can now be carried out for the first time.
Schaeffler Noise Index
The SGI value is based on the maximum permissible noise level of a bearing in accordance with internal standards, which is calculated on the basis of ISO 15242. In order that different bearing types and series can be compared, the SGI value is plotted against the basic static load rating C0.
This permits direct comparisons between bearings with the same load carrying capacity. The upper limit value is given in each of the diagrams. This means that the average noise level of the bearings is lower than illustrated in the diagram.
The Schaeffler Noise Index is an additional performance characteristic in the selection of bearings for noise-sensitive applications. The specific suitability of a bearing for an application in terms of installation space, load carrying capacity or speed limit for example, must be checked independently of this.
Schaeffler Noise Index for single row full complement cylindrical roller bearings
SGI = Schaeffler Noise Index
C0 = basic static load rating
The operating temperature of the bearings is limited by:
- the dimensional stability of the bearing rings and cylindrical rollers
- the cage
- the lubricant
Possible operating temperatures of single row cylindrical roller bearings ➤ Table.
Permissible temperature ranges