Installation and removal of bearings - technical principles

Scope of the study

This study defines the basic technical requirements for mounting and dismounting rolling bearings in accordance with the principles of industrial practice and ISO standards.

The procedures apply to ball bearings, roller bearings, spherical roller bearings, needle bearings, and cylindrical and tapered bore bearings.

Preparation for installation

Before installation, verify the compatibility of the bearing designation with the technical documentation. Bearings should be stored in their original packaging until direct installation.

Mating components, especially shafts and body seats, must be checked for:

– dimensional accuracy,
– geometric tolerances,
– surface roughness,
– concentricity,
– absence of mechanical damage.

Settling surfaces should be clean, degreased and treated with a thin layer of lubricant to facilitate installation.

Internal clearance control

Before mounting, check the radial clearance of the bearing according to the requirements of ISO standards. For bearings with increased clearance, the designations C1, C2, CN, C3, C4, C5 are used.

If there is no clearance class symbol in the bearing designation, normal clearance is taken.

A reduction in internal clearance can occur as a result:

– application of excessive compression,
– thermal expansion of the shaft,
– axial displacement of rings in tapered roller bearings.

In high-temperature assemblies, it is recommended to use bearings with a clearance of C3 or more.

Assembly methods

Bearing assembly can be carried out by mechanical, thermal or hydraulic methods.

When fitting with a press fit on the shaft, the mounting force should be transmitted only through the inner ring. When mounting in the body – only through the outer ring.

It is not permissible to transfer assembly force through rolling elements.

For bearings mounted with higher press fit, heating in an oil bath to 80-90°C is recommended. For sealed bearings, heating should be done in a controlled thermal environment.

Large-diameter bearings and those with a tapered bore are recommended to be mounted using the hydraulic method.

Post installation inspection

Once the installation is complete, check:

– freedom of shaft rotation,
– absence of jamming,
– correctness of axial adhesion of rings to dams,
– correct axial or radial clearance.

Trial startup should be done at low speed with no load. Abnormal sounds, excessive vibration or rapid temperature rise are indicative of installation errors.

Under normal operating conditions, the bearing temperature should not exceed the ambient temperature by more than 30°C.

Dismantling

Disassembly of bearings should be carried out only with suitable pulling tools or hydraulic devices.

Disassembly force must be applied to the ring seated with pressure.

Do not use direct impacts on rings or rolling elements.

When dismantling bearings intended for reuse, special care must be taken to avoid damage to the raceways and rolling elements.

Post-assembly diagnostics

Noise, vibration and temperature rise are the primary indicators of improper installation.

Swishing may indicate insufficient lubrication.
A metallic sound may indicate insufficient clearance.
An irregular noise at constant speed may indicate damage to rolling elements.

If abnormalities are found, operation should be stopped and the installation should be verified.

Reference to standards

ISO 286 – system of tolerances and fits
ISO 492 – accuracy of rolling bearings
ISO 1101 – geometric tolerances
ISO 5753 – internal clearance of bearings