Handling and installation

Miniature ball bearings can only perform their function properly if they are installed correctly.
Experience has shown that malfunctions and excessive wear are in most cases due to improper installation. The following points should therefore be carefully observed:

Selection of the fit:

The proper functioning of the ball bearings largely depends on the quality of the fit. The following aspects must be taken into account when selecting a suitable fit:

  • Surface quality and dimensional precision of the shaft and housing. These two factors not only influence the frictional torque and running noise, but also ensure that the ball bearing runs perfectly, especially at high speeds.
  • Temperature fluctuations: At higher temperatures, the outer ring loosens due to the radial expansion of housing made from lighter alloys, while the radial expansion of a lighter alloy shaft reduces the radial play.
    On the other hand, the difference between the axial expansion of a steel shaft and a light metal housing can lead to an additional axial load.

  • Size, direction and type of loads. The load on a ball bearing at rest should not exceed its static load rating.

  • Axial and radial loads or combinations of both, as well as bidirectional loads which lead to rapid load changes.
    Such impact loads are very damaging to miniature ball bearings and should be avoided wherever possible.

  • Relative movement of the inner and outer rings.

  • The precision and radial rigidity required for the entire assembly.
    The two tables in the following section, one for housings and one for shafts, show in the middle column the most favorable manufacturing tolerances for an optimum design of the fit, where:

  • The left side shows the load types and speeds for the respective application

  • The right side details the desired accuracy, radial rigidity and application

The tolerances are given in μm and only apply if the material for the shafts and housings has the same coefficient of expansion as the steel used for the ball bearings. In all other cases, the different expansion values must be taken into account.

In general, the fits specified in these tables are suitable for normal operating temperatures.

High temperature differences and the direction of heat flow in the bearing must be taken into account.

Laboratory tests are often required to find the best solutions. The installation and operating conditions are important here.

Such tests can be carried out in the myonic laboratory. For easier installation, myonic ball bearings can be classified on delivery according to dimensional groups of the bore and / or outside diameter.