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6921-2RS Thin-Section Deep Groove Ball Bearing for Industrial Machinery & Automation | 105×145×20 mm

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.

6921-2RS Deep Groove Ball Bearing 105x145x20 mm | Thin-Walled Architecture | Double Rubber Sealed

Manufactured to precise international standards, this thin-section bearing allows engineers to maximize space efficiency without sacrificing structural integrity. The signature narrow profile drastically reduces overall assembly weight, enabling cleaner integration into large-diameter hollow shafts and low-profile housings. The contact rubber seals safeguard the micro-honed steel raceways from abrasive contamination, absorbing minor misalignments and cutting down maintenance overhead. As a result, the 6921-2RS delivers exceptionally stable operational endurance, standing out as a long-term powerhouse for demanding industrial drive systems.

6921-2RS Thin-Section Deep Groove Ball Bearing for Industrial Machinery & Automation | 105×145×20 mm

Comprehensive Applications

Engineered for large-bore, narrow-clearance industrial and mechanical systems:

Electrical & Power Transmission
  • Large-diameter electric motors and generators
  • Variable speed gearboxes and speed reducers
  • Wind turbine pitch control systems and monitoring components
  • Power distribution rotary contacts
Industrial Robotics & Automation
  • Multi-axis robotic arm articulation joints and slewing bases
  • Hollow-shaft servo motor assemblies and rotary actuators
  • Automated pick-and-place material handling gantries
  • AGV (Automated Guided Vehicle) wheel hubs and drive units
Specialized Hardware & Marine
  • Packaging machinery rotary turntables and sealing rings
  • Marine winch mechanisms and deck crane pivots
  • Fitness equipment pulleys and high-capacity flywheel mounts
  • Automated commercial gate operator systems
Manufacturing & Heavy Equipment
  • High-precision textile machinery spindles and looms
  • Commercial printing press cylinders and paper feed rollers
  • Industrial fluid pumps and high-volume ventilation fans
  • Material processing conveyors and sorting machinery

Key Performance Features

01. High-Efficiency Thin-Section Geometry

Featuring a large 105mm bore paired with a streamlined 145mm outer diameter, this bearing provides an optimal balance between large shaft capacity and low radial space requirements. The double rubber seals (2RS) secure the internal components from high-grit dust and moisture splashback, ensuring industrial machinery operates continuously without premature breakdown or power loss.

02.Vacuum-Degassed Chrome Steel (GCr15)

Despite its thin-walled cross section, the 6921-2RS is forged from high-purity GCr15 chrome steel. Specialized thermal conditioning ensures the structural raceways and rolling elements achieve uniform hardness and exceptional fatigue resistance, minimizing frictional heat buildup and dampening system vibrations under high load conditions.

03. Advanced Double-Lip Rubber Seals

The primary protective feature of the 2RS series is the chemical-resistant nitrile butadiene rubber (NBR) seal bonded to steel reinforcements. This configuration creates a tight, continuous contact seal that shuts out external moisture and debris while safely sealing in the factory-applied high-performance lubricating grease for life.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 6900 Series (Thin Section / Metric)
Basic Designation 6921
Suffix 2RS (Double Rubber Contact Seals)
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
Seal Material Nitrile Butadiene Rubber (NBR) with Steel Backing
Dynamic Load Rating (Cʳ) 42.5 kN
Static Load Rating (C₀ʳ) 42.0 kN
Limiting Speed (Grease) 2,500 r/min
Limiting Speed (Oil) 5,100 r/min (Open Base Reference)
Weight (approx.) 0.82 kg

Interchange Part Numbers

Directly drops into assemblies utilizing the following equivalent competitor part numbers:

  • SKF/FAG: 61921-2RS1 / 61921-2RSR
  • NSK: 6921DDU
  • KOYO: 6921-2RS
  • NTN: 6921LLU

Design & Configuration

Shipped ready for deployment, the standard Welink 6921-2RS comes pre-lubricated with standard industrial-grade lithium grease optimized for structural damping and moderate temperature spans. For high-corrosion or sanitization-heavy environments, we also manufacture this profile in AISI 440C stainless steel (S6921-2RS). If your application operates under intense thermal environments or high-vibration criteria, contact our technical support division to discuss specialized internal clearances (such as C3 or C4) and high-temperature grease configurations.

"By pairing a massive 105mm bore capacity with an ultra-lean thin-section layout, the 6921-2RS delivers optimal space management and uncompromising reliability to heavy industrial equipment designs."

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Details

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