Cage
Käfig
The cage keeps the rolling elements evenly spaced, prevents mutual contact and guides them through the unloaded zone. It carries no external load but strongly influences friction, limiting speed and noise. Common designs are pressed steel cages (robust standard), machined brass cages (high cage strength, for high temperatures and rib guidance) and glass-fibre-reinforced polyamide cages (quiet, good emergency-running properties, favourable under shock thanks to elasticity and low mass, but limited continuous temperature and sensitive to some oil additives). Cage material is coded in the manufacturer-specific designation suffixes. High cage strength, heat and rib guidance favour machined metal cages, while shock and high accelerations favour polyamide; cage wear is a typical secondary damage from lubricant starvation, and cage frequencies are a key condition-monitoring signal.