einpressen

Einpressen, or press fitting, is a joining method in which a part is assembled into or onto another part by an interference fit. The connection is typically permanent or semi-permanent and relies on plastic and elastic deformation to maintain contact. It is widely used in mechanical engineering for components such as bearings in housings, gears on shafts, bushings in pulleys, and sleeves in assemblies.

In practice an interference is created by using slightly oversized or undersized parts, or by expanding the outer part and/or cooling the inner part. In most cases the parts are pressed together with a mechanical or hydraulic press. Chamfers and deburring reduce edge damage, and lubrication may be used to ease insertion. After assembly, residual stresses and the resulting interference hold the parts in alignment and transmit axial and radial loads without fasteners.

Design and process considerations include selecting tolerances and fit class to meet load and misalignment requirements, material hardness, surface finish, and potential for cold work or crack formation. Heat treatment, coatings, or using a softer insert can influence service life. Correct alignment during pressing is essential to avoid binding or uneven seats.

Advantages include strong, precise joints without welding or adhesives and rapid assembly. Limitations include difficulty of disassembly, risk of damage if excessive force is used, and the need for appropriate equipment and process control.

Typical applications are bearings seated in housings, gears on shafts, hubs on wheels, and bushings pressed into bores.