Lospassung

Lospassung is a term used in mechanical engineering to describe a loose fit between two mating parts, such as a shaft and a bore. In this type of fit, the bore is sized larger than the shaft, creating clearance that allows relative movement between components. Lospassung is typically employed where easy assembly, simple alignment, and the possibility to replace parts are prioritized over tight positioning or high stiffness.

Applications include bushings, sleeves, collars, pulleys, and gears mounted on shafts, as well as removable components in housings and clamped assemblies. The fit facilitates assembly without special forces and reduces the risk of binding if parts are misaligned during installation or subject to small dimensional variations from manufacturing, wear, or thermal effects.

Design considerations involve specifying tolerances that guarantee a minimum clearance under expected temperatures and loads, selecting appropriate surface finishes, and accounting for lubrication and thermal expansion. ISO fits and tolerancing standards provide guidelines for hole and shaft size combinations that yield clearance fits; designers balance clearance against stability and wear.

Advantages of a lospassung include easy assembly, straightforward maintenance, and tolerance to misalignment. Drawbacks are reduced positional accuracy, potential wobble or backlash, and greater wear risk in rotating assemblies if lubrication is inadequate. Lospassung is one option among fit types, alongside interference and transition fits, depending on function and assembly requirements.