klemringen

Klemringen, commonly translated as retaining rings or clamp rings, are circular fasteners used to secure components on a shaft or inside a bore. They provide axial retention by sitting in grooves on a shaft or inside a bore, or by applying a clamping force around a cylindrical surface. The term is used in Dutch mechanical engineering to describe this family of ring-shaped restraints that locate parts and prevent axial movement.

There are two primary forms: external retaining rings, which fit into grooves on a shaft, and internal retaining rings, which sit in grooves inside a bore. Both types are typically made from spring steel and installed or removed with specialized pliers. Some designs function as clamp rings that generate clamping force against a shoulder or mating surface, rather than relying solely on a groove for retention.

Materials and finishes vary by application. Common materials include spring steel and stainless steel, with coatings such as zinc, nickel, or passivation to improve corrosion resistance. The choice depends on strength requirements, environmental exposure, temperature, and compatibility with mating parts.

Installation and handling require care. Rings are under spring tension and can snap suddenly when released. Installation and removal typically use snap ring pliers or similar tools, following proper procedure to avoid injury and damage to components.

Applications are widespread in automotive, gearboxes, bearings, pulleys, hydraulics, and other mechanical assemblies. Selection factors include inner or outer diameter, groove width, ring thickness, load direction, operating temperature, and corrosion resistance. International standards for retaining rings (DIN, ISO) define dimensions and tolerances for external and internal variants. Regular inspection and replacement are advised if rings show deformation, cracks, or corrosion.