Binnenring

Binnenring is the Dutch term for the inner ring (inner race) of a rolling bearing. It forms one of the two raceways that guide the rolling elements (balls or rollers) and, together with the outer ring, encloses the lubricant and maintains proper spacing. The inner ring is typically mounted on the shaft and rotates with it, while the outer ring is fixed to the housing; depending on the design, either ring can be the rotating member.

Construction and mounting: Inner rings are usually machined from bearing steel, hardened and ground to a precise bore and raceway profile. The bore diameter defines the shaft fit and is often an interference fit to secure the ring on the shaft. The raceway geometry, including curvature and surface finish, is specified for the bearing type and load requirements. Some inner rings include features such as keyways, seals, or lubrication grooves to accommodate mounting and improve sealing and lubrication.

Function and applications: The inner ring provides the rotating raceway for the rolling elements and transmits radial loads from the shaft to the bearing. In many radial bearings, the inner ring carries axial loads in combination with the outer ring, depending on the design. In thrust bearings or special arrangements, the rotating member may be the outer ring instead, or both rings may move relative to the load. The choice of bearing type, fit, and lubrication affects performance and service life.

Maintenance and wear: Wear or damage to the inner ring compromises clearance and load distribution, leading to increased friction and heat. Regular inspection focuses on wear, indentation, pitting, and bore runout; lubrication and seals must be maintained, and damaged inner rings are replaced as part of bearing service.