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INA Bearings size is selected, in addition to performance issues, we must first take into account the bearing life. INA rolling bearings performance, use, maintain its performance shall be within the prescribed period. Even if the correct bearings used in some purposes, after a certain period of time, the increase in noise, vibration, due to wear and tear caused by the decline in accuracy, grease aging, fatigue stripped of the rolling surface is no longer available. This period of INA bearings until you can not use the broad bearing life. Respective known as: noise life, abrasion life, grease life, rolling fatigue life. Reference "INA Bearing Life," there are more details on the definition of the INA bearing life.
INA bearings basic dynamic load rating and fatigue life
INA basic dynamic load rating
The so-called, said INA rolling bearings load capacity of the basic rated dynamic load and rotation in the inner ring, outer ring under static conditions, the rated fatigue life of 1 million revolutions, changes in the load direction and size. Radial bearings, direction and size of the center of the load. INA thrust bearings, the direction is consistent with the central axis, the size of the axial load. The basic dynamic load rating C, the different structure of the bearings, radial bearings for Cr, thrust bearing Ca recorded at INA Bearing table.
Mechanical design life forms see INA bearing life which form a reference
INA Bearing according to the basic dynamic load rating
The relationship between INA rolling bearings basic dynamic load rating, the bearing load and the rated fatigue life, as follows:
Ball bearings L = (C / P) 3
Roller bearings L = (C / P) 10/3
Where:
L: Rating fatigue life of rotating unit (106)
P: bearing load (the equivalent dynamic load) (N) {kgf}
C: basic rated dynamic load (N) {kgf} (Radial bearings cr said thrust bearing ca)
INA Bearing a certain rotation speed, bearing fatigue life, time to indicate more convenient. Cars, vehicles and other general Mileage. (Total number of revolutions)
The basic dynamic load rating according to the temperature correction
INA rolling bearings used in high temperature bearing hardness decreased, lower than the fatigue life at room temperature. Therefore, the basic dynamic load rating to the corresponding estimated smaller. Amendment in accordance with below.
Ct = ft * C
Where
Ct: the use of temperature correction of the basic rated dynamic load (N), {kfg}
ft: temperature coefficient
C: basic rated dynamic load (N), {kgf}
INA Bearing in temperatures above 120 ℃, large INA Bearing size changes, so should be dimensionally stable. Furthermore, the basic dynamic load bearing dimensionally stable processing, and sometimes lower than the basic dynamic load rating recorded in the bearing size table.
Amendments to the rated fatigue life
Rated the basic formula of the fatigue life
Ball Bearing L10 = (C / P) 3
Roller bearings L10 = (C / P) 10/3
L10 is the reliability for 90% of the rated fatigue life. However, depending on the use of machinery, and sometimes need to calculate the rated fatigue life of more than 90% high reliability.
With the improvement of the bearing steel, the fatigue life is also extended. , That the raceways and the flow of body contact part of the film thickness on the fatigue life according to the study of the elastohydrodynamic lubrication theory. The above factors are reflected in the calculation of the fatigue life, you can use the following compensation coefficient, and modify the rated fatigue life.
Lna = a1a2a3L10
Where:
Lna: taking into account the fatigue life reliability, materials, improved lubrication conditions
L10: 90% rated the reliability of fatigue life.
a1: reliability coefficient
a2: bearing characteristic coefficient
a3: conditions of use factor
INA Bearing coefficient a2 compensation brought about by the material improvement of the fatigue life extension coefficient values greater than 1.
INA all undergo a rigorous selection of vacuum degassed bearing steel. The use of such materials, the standard INA Bearing INA study was to detect that life is significantly improved.
The condition factor a3 compensation INA Bearing conditions, particularly the coefficient of the lubrication conditions affect the fatigue life. If the inner and outer rings between the no tilt, there is adequate oil film thickness in the INA bearing operation, you can set a3 is greater than or equal to 1, but less than in the following situations a3 (including: between the ring and rolling element contact part of the lubricating oil viscosity, low peripheral speed of the rolling body, INA Bearing high temperature lubricant mixed with foreign matter, moisture and other large tilt between the inner and outer rings.)
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 6928 NSK | 140 | 190 | 24 |
| 6828 NSK | 140 | 175 | 18 |