Grundlager

Grundlager is a German term used in mechanical engineering to denote the main bearing arrangement that supports a rotating shaft and transmits loads to the machine foundation. The word combines Grund (base or foundation) and Lager (bearing or support). In many technical texts it is used interchangeably with Hauptlager, though some fields distinguish between Grundlager as the primary, load‑carrying bearing and auxiliary or secondary bearings.

Grundlager perform two fundamental roles: they support radial and axial loads and maintain the correct shaft position relative to other components. They must provide adequate stiffness, allow controlled rotation, and tolerate misalignment and shaft runout within design limits. The choice of bearing type for a Grundlager depends on load, speed, lubrication, precision, and space constraints. Common realizations include plain bearings (Gleitlager) that use a lubricant film, and rolling-element bearings (Wälzlager) such as ball or cylindrical roller bearings; in many machines the engine’s crankshaft main bearings are a typical example of a Grundlager.

In design practice, Grundlager sit in bearing housings or pedestals and require proper lubrication management, cooling, and sealing. Misalignment, insufficient lubrication, or overheating can lead to wear, increased friction, or shaft damage. Maintenance often involves monitoring oil quality and level, vibration analysis, and periodic inspection for wear and clearances.

The term appears in German-language engineering literature and standards. See also Lager, Hauptlager, Gleitlager, and Wälzlager for related concepts.