Leave A Message
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.
Submit
69 Series
Home Deep Groove Ball Bearings 69 Series

6921-ZZ Thin-Section Deep Groove Ball Bearing for Industrial Automation & Heavy Machinery | 105×145×20 mm

6921-ZZ Thin-Section Deep Groove Ball Bearing for Industrial Automation & Heavy Machinery | 105×145×20 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.

6921-ZZ Deep Groove Ball Bearing 105x145x20 mm | Slim-Profile Design | Double Shielded

Manufactured to rigorous ISO precision standards, this thin-section radial bearing optimizes housing layouts by delivering a high-capacity performance envelope in a compact radial cross-section. This unique architecture allows engineers to utilize larger hollow shafts for routing cables, piping, or secondary drive shafts without increasing overall system footprint or weight. The non-contact metal shields protect the micro-polished internal raceways without generating the localized thermal stress typically associated with rubber lip seals. As a result, the 6921-ZZ comfortably sustains thousands of revolutions per minute under consistent operation, serving as a dependable, maintenance-free core for automated industrial plants.

6921-ZZ Thin-Section Deep Groove Ball Bearing for Industrial Automation & Heavy Machinery | 105×145×20 mm

Comprehensive Applications

Purpose-built for large-diameter, space-optimized mechanical environments:

Industrial Automation & Robotics
  • Multi-axis industrial robotic arms and articulating elbow joints
  • High-precision rotary indexing tables and positioning carousels
  • Automated pick-and-place gantry systems
  • Heavy-duty servo drives and hollow-shaft torque motors
Heavy Machinery & Power Transmission
  • Textile manufacturing machinery, spinning frames, and looms
  • Large-format industrial printing presses and paper converting rollers
  • Industrial gearboxes and speed reducers with large center bores
  • Material handling conveyor pulley systems and sorting systems
Medical Equipment & Testing Instruments
  • Large-scale medical imaging systems, CT scanners, and X-ray mounts
  • Automated laboratory sample processing carousels
  • Precision optical tracking mounts and large radar pedestals
  • Industrial balancing rigs and measuring machinery
Marine & Energy Sectors
  • Wind turbine secondary yaw/pitch control mechanisms
  • Winch assemblies, cable drums, and marine steering hardware
  • Hydro-power control valve actuators
  • Smart warehouse automated guided vehicles (AGV) main wheel hubs

Key Performance Features

01. Optimized Slim-Profile Geometry

With a generous 105mm inner bore and a relatively narrow 145mm outer diameter, this bearing provides an exceptional stiffness-to-weight ratio. The double pressed-steel shields (ZZ) offer dependable particulate shielding without causing parasitic frictional drag, preserving energy efficiency and ensuring large automated drive systems operate with minimal power loss.

02. Premium Vacuum-Degassed Chrome Steel (GCr15)

Engineered for continuous heavy-duty cycles, the 6921-ZZ is constructed from ultra-clean GCr15 high-carbon chrome steel. Through advanced structural heat treatment, the high-grade internal balls and deep-groove raceways achieve superior hardness and wear resistance, delivering quiet, vibration-free operation even under high radial load conditions.

03. High Radial Rigidity & Weight Mitigation

The defining feature of the 69-series is its thin section, which drastically reduces the structural mass of the bearing itself compared to standard 62- or 63-series bearings with identical bore sizes. This enables ultra-compact housing geometries while still providing the strong radial and moderate axial load support necessary for heavy industrial shafts.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series Thin Section / Slim Profile Series (69 Series)
Basic Designation 6921
Suffix ZZ (Double Steel Shields)
Bore Diameter (d) 105 mm
Outer Diameter (D) 145 mm
Width (B) 20 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material Pressed Steel
Dynamic Load Rating (Cʳ) 47.00 kN
Static Load Rating (C₀ʳ) 42.00 kN
Limiting Speed (Grease) 4,300 r/min
Limiting Speed (Oil) 5,300 r/min
Weight (approx.) 0.840 kg (840 g)

Interchange Part Numbers

Directly replaces the following equivalent manufacturer part numbers:

  • SKF/FAG: 6921-2Z / 6921 ZZ
  • NSK: 6921ZZ
  • KOYO: 6921ZZ
  • NTN: 6921ZZ

Design & Configuration

Out of the box, the standard 6921-ZZ is pre-lubricated with a premium industrial low-noise grease suited for broad operating temperature ranges. Because thin-section bearings are frequently integrated into highly specialized machinery, Welink Bearing also offers custom configurations featuring custom high-temperature greases or high-grade stainless steel components for corrosive or wet environments. If your system requires absolute fluid containment rather than maximum speed efficiency, please consult our engineering support team regarding customized rubber-sealed (2RS) variants.

"By successfully packing a massive 105mm bore capacity into a compact 20mm width profile, the 6921-ZZ resolves severe footprint limits and mass reduction challenges in modern industrial engineering."

Related Products

Precision 6921-ZZ Thin Section Bearing 105x145x20mm compatible with SKF 6921-2Z and NSK 6921ZZ for Industrial Robotic Joints and Rotary Tables
6921-ZZ Thin-Section Deep Groove Ball Bearing for Industrial Automation & Heavy Machinery | 105×145×20 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.

Details
Industrial 6921-2RS Deep Groove Ball Bearing 105x145x20mm featuring Double Rubber Seals for Dust Protection in Industrial Robotics and Heavy Machinery
6921-2RS Thin-Section Deep Groove Ball Bearing for Industrial Machinery & Automation | 105×145×20 mm

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.

Details
Unshielded 6921 Open Deep Groove Bearing 105x145x20mm compatible with SKF 6921 and NSK 6921 for Industrial Gearboxes and Oil Bath Lubrication Systems
6921 Open Thin-Section Deep Groove Ball Bearing for Gearboxes & Oil-Lubricated Systems | 105×145×20 mm

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.

Details
6920-2RS Deep Groove Ball Bearing featuring Double NBR Rubber Seals for maximum moisture and debris protection in harsh industrial environments
6920-2RS Thin-Section Sealed Ball Bearing for Industrial Machinery & Heavy Automation | 100×140×20 mm

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.

Details
6918 Open Deep Groove Ball Bearing 90x125x18mm Unsealed for Oil Lubricated Industrial Gearboxes and Machine Tools
6918 Unsealed Thin-Section Ball Bearing for Precision Machinery & Heavy-Duty Gearboxes | 90×125×18 mm

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.

Details
85x120x18mm 6917-2RS Sealed Ball Bearing compatible with NSK 6917DDU and SKF 6917-2RS1 for Packaging Machinery and Automated Conveyors
6917-2RS Precision Sealed Ball Bearing | 85×120×18 mm for Conveyor Systems & Automated Drives

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.

Details
Thin Section 6919-ZZ Ball Bearing with Double Metal Shields for 95mm Shaft Applications in Robotics and Industrial Motors
6919-ZZ Thin-Section Deep Groove Ball Bearing | 95×130×18 mm for Space-Constrained Machinery & Large Shafts

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.

Details
6915-2RS Thin Section Deep Groove Ball Bearing 75x105x16mm showing NBR Rubber Contact Seals for Robotics and Machine Tool Spindles
6915-2RS Thin Section Deep Groove Ball Bearing for Robotics & Precision Automation| 75×105×16 mm

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.

Details

Leave A Message

Leave A Message
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.
Submit

Home

Products

whatsApp

contact