Bearing Shrink Fitting

Induction heating is the preferred method for high-precision heat shrink assembly. The process follows three key steps:

– Heat Generation: an alternating magnetic field induces eddy currents directly within the outer component, heating it rapidly and without contact.

– Controlled Expansion: thanks to precise temperature management, the hole expands uniformly until it overcomes the interference with the shaft.

– Thermal Contraction: once the shaft is inserted, the cooling of the outer component causes it to shrink, creating an unbreakable and perfectly distributed mechanical bond.

A classic example of this technology in action is the insertion of bearings into aluminum casings. In this application, precision is critical to avoid damaging the housing or the bearing race.

The Challenge: to join two bearings into an aluminum seat where the shaft’s outer diameter is greater than the hole’s inner diameter at room temperature.
Our Solution: the bores of the aluminum casing are heated via induction to achieve a calculated thermal expansion. Once the internal diameter of the bores exceeds the outer diameter of the bearings, the bearings are seated effortlessly. As the aluminum cools, it grips the bearings with a high-resistance radial force, ensuring a permanent and stable coupling.