Bearings
Mounting bearings
Properly performed installation is of great importance for the proper functioning of the bearings. Three mounting methods can be distinguished:
- Mechanical method of mounting
- Thermal method of mounting
- Hydraulic method of mounting
For the smaller bearings, including the miniature bearings, the mechanical mounting method is used because these bearings can be mounted with light press fits. Professional tools such as impact sockets or a mechanical press can be used for this.
In the thermal method, a bearing is mounted by heating the parts. Mounting bearings with the thermal method is often used for larger bearings and for serial mounting. It is important to have good control over the temperature to avoid that preservatives and greases are not burned. The thermal mounting of bearings can be carried out by means of an oil bath, a hob, an oven or with an induction heating device. An induction heating device is the most reliable method because it allows the temperature to be regulated by means of a sensor.
Mounting with the hydraulic method is mainly also done with larger bearings with a bore from 200 mm. This mounting method uses a hydraulic press.
Bearing Damage
There are two categories of damage that can occur on bearings:
- Unavoidable damage from material fatigue and surface depletion
- Avoidable damage due to production errors or external influences
Despite very careful and high quality standards that bearing manufacturers must adhere to, production errors can never be completely ruled out. If there is a production error, it can be recognized by, for example, the lack of a ball or a roller in the bearing or by not or insufficiently worked surface in a bearing.
There are a number of external influences that can also cause damage to the bearing. These can be recognized by, for example:
- The presence of walking tracks
- The occurrence of primary damage due to wear, indentations, material smearing, surface depletion, corrosion and passage of electrical current
- The occurrence of secondary damage due to chipping and breakage or cracking of bearing components
With any bearing that is used, over time, and depending on how much it is used, light or heavier marks are visible in the raceways or on the rolling bodies. The presence of these traces need not be alarming in itself, as there are numerous bearings with obvious traces that still function excellently. Running tracks can, however, provide a good picture of, among other things, the correctness of the mounting and the choice of fit and clearance of the bearing construction.