6918 Unsealed Thin-Section Ball Bearing for Precision Machinery & Heavy-Duty Gearboxes | 90×125×18 mm

Designed specifically for space-constrained, large-shaft assemblies requiring high radial rigidity and minimized weight, the 6921-ZZ is a premium thin-section deep groove ball bearing. Outfitted with dual non-contact metallic shields (ZZ), it delivers exceptional defense against coarse dust and factory debris while ensuring reliable containment of the factory-applied lubrication. Because the metal shields avoid contact friction with the inner ring, the 6921-ZZ maintains minimal running torque and ultra-smooth rotation. This makes it an essential mechanical component for large-bore, weight-sensitive 105mm applications, including industrial robotic joints, heavy-duty rotary tables, and complex automated equipment.

Developed to support reliable radial and multi-directional axial loads within tight radial profiles, the 6921-2RS is a premium thin-section deep groove ball bearing equipped with dual synthetic rubber seals. Outfitted with heavy-duty contact seals (2RS), it provides a highly resilient barrier against fine dust, moisture, and particulate contaminants while preventing internal grease migration. Because these reinforced rubber lips maintain direct contact with the inner ring recess, the 6921-2RS ensures structural protection and lubrication retention in harsh environments. This makes it an invaluable mechanical component for large-bore, weight-sensitive 105mm shaft applications, including industrial robotic joints, heavy manufacturing automation, and rotating platforms.

Engineered for internal mechanical assemblies where external sealing is provided by the housing, the 6921 Open is a high-performance thin-section radial ball bearing. Completely unshielded and unsealed, this open-type configuration allows for unrestricted flow of fluid lubricants directly into the rolling elements. Because there are no physical barriers or rubbing seals, the 6921 Open achieves absolute zero shield-induced friction, ensuring optimal thermal dissipation and maximum rotational efficiency. It is the ideal component for heavy-duty 105mm shaft applications enclosed in oil bath environments, such as industrial transmissions, large centrifugal pumps, and enclosed machine tool spindles.

Designed for heavy-duty industrial applications where radial space is limited but environmental protection is paramount, the 6920-2RS is a high-performance thin-section deep groove ball bearing. Equipped with twin nitrile rubber contact seals (2RS), this bearing excels at locking in premium factory grease while completely blocking the ingress of moisture, dust, and abrasive particulate matter. While the contact seals introduce slightly more friction than unsealed or metal-shielded counterparts, they provide unparalleled longevity and reliability in harsh, contamination-prone operating environments, making the 6920-2RS an exceptional solution for 100mm bore requirements in gearboxes, large robotics, and agricultural equipment.

Engineered for internal mechanical applications where external contamination is not a factor, the 6918 is a premium open-type deep groove ball bearing. Featuring an unsealed, shield-free architecture, this bearing offers absolute zero seal friction, allowing the internal rolling elements to interact directly with oil-bath or circulating lubrication systems. This unrestricted flow makes the 6918 the ultimate choice for large-bore (90mm) applications requiring superior thermal dissipation and ultra-smooth rotation, such as heavy industrial transmissions, machine tool spindles, and aerospace components.

Engineered to deliver exceptional reliability in environments where radial space is restricted, the 6917-2RS is a premium thin-section deep groove ball bearing. Featuring dual nitrile rubber contact seals (2RS), this bearing is specifically designed to lock in factory lubrication while creating an impenetrable barrier against environmental contaminants like dust, moisture, and manufacturing debris. While rubber seals introduce a nominal increase in friction compared to open bearings, they drastically extend the service life of the component in exposed conditions. This makes the 6917-2RS an invaluable asset for 85mm bore applications, including packaging machinery, medium-duty gearboxes, and automated material handling systems.

Engineered for precision applications where space is at a premium and weight reduction is critical, the 6919-ZZ is a high-performance thin-section deep groove ball bearing. Featuring dual pressed-steel shields (ZZ), it guards internal raceways against dust contamination while retaining factory-filled lubricant. The non-contact design of these metal shields minimizes rotational drag and heat generation, making it an ideal choice for 95mm shaft configurations including industrial automation, large electric motors, and rotary tables.

Engineered for applications where space conservation and weight reduction are critical, the 6915-2RS is a premium thin-section deep groove ball bearing from the 6900 series. Equipped with dual synthetic rubber contact seals (2RS), this bearing offers unparalleled defense against moisture, coolant, and harsh industrial debris while permanently retaining its high-performance factory grease. By utilizing contact sealing technology, the 6915-2RS provides maximum environmental protection, making it an ideal solution for large-diameter shaft applications such as industrial robotics, CNC rotary tables, and aerospace mechanisms.