Ball Bearings
Flexible Bearings for Harmonic Drive
The NU/NJ/NUP/N/NF/NP cylindrical roller bearings are engineered for high radial load capacity, low friction, and long-term operational reliability. With a compact structure and high rigidity, this bearing series maintains excellent running accuracy under high-speed or heavy-load conditions. By optimizing roller and raceway geometry and applying high-precision manufacturing processes, these bearings deliver higher efficiency, extended service life, and reduced maintenance requirements in industrial transmission systems.
Key Features
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High Radial Load Capacity
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Low Friction and High Operating Efficiency
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High Rigidity and Precision Performance
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Multiple Structural Types (NU / NJ / NUP / N / NF / NP)
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Long Service Life and Reduced Maintenance
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Wide Size Range and Customization Support
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Description
Reviews
600 Series – Standard Miniature Deep Groove Ball Bearing
Most Popular Customizable
The 600 series is the most widely used standard miniature deep groove ball bearing, offering an ideal balance of load capacity and high-speed performance in a compact form factor. Suitable for both radial and light axial loads.
- Inner Diameter (d): 6–9 mm
- Outer Diameter (D): 17–24 mm
- Width (B): 6–7 mm
- Basic Dynamic Load Rating (Cr): 2,260–3,290 N
- Basic Static Load Rating (C₀r): 1,100–1,960 N
- Limiting Speed (Grease): 38,000–45,000 rpm
618 Series – Extra-Light Thin-Wall Miniature Bearing
Ultra-Compact Customizable
The 618 series features an extra-light cross-section, providing the smallest possible envelope dimensions for space-critical applications. The reduced section width makes them ideal for thin-wall housings and lightweight instrument designs.
- Inner Diameter (d): 6–9 mm
- Outer Diameter (D): 13–17 mm
- Width (B): 3.5–4 mm
- Basic Dynamic Load Rating (Cr): 1,100–1,300 N
- Basic Static Load Rating (C₀r): 440–660 N
- Limiting Speed (Grease): 40,000–55,000 rpm
619 Series – Light Miniature Deep Groove Ball Bearing
Higher Load Capacity Customizable
The 619 series provides a larger ball complement than the 618 series while maintaining a compact cross-section. It offers a superior balance of load capacity, speed, and overall dimensions for general-purpose miniature applications.
- Inner Diameter (d): 6–9 mm
- Outer Diameter (D): 15–20 mm
- Width (B): 5–6 mm
- Basic Dynamic Load Rating (Cr): 1,300–2,500 N
- Basic Static Load Rating (C₀r): 520–1,100 N
- Limiting Speed (Grease): 34,000–48,000 rpm
Flanged Miniature Ball Bearing (F600 Series)
Easy Positioning Customizable
Flanged miniature bearings feature an integral outer ring flange that provides positive axial location without additional retaining components. The flange enables simple press-fit installation and prevents bearing walk in through-bore housings.
- Inner Diameter (d): 6–9 mm
- Outer Diameter (D): 17–24 mm
- Flange Outer Diameter (Dfl): 19.5–26.5 mm
- Width (B): 6–7 mm
- Basic Dynamic Load Rating (Cr): 2,260–3,290 N
- Limiting Speed (Grease): 38,000–45,000 rpm
Sealed & Shielded Miniature Ball Bearing (2RS / ZZ)
Pre-lubricated Maintenance-Free
Sealed (2RS) and shielded (ZZ) miniature variants offer built-in contamination protection with factory pre-lubrication, making them ideal for environments where re-lubrication is impractical or impossible.
- Shield Type (ZZ): Non-contact metal shields, minimal friction loss, high-speed capable
- Seal Type (2RS): Rubber contact seals, superior dust and moisture exclusion
- Available Series: 600, 618, 619, F600 (flanged)
- Operating Temp (Standard): −20 to +120 °C
- Lubrication: Factory pre-filled precision instrument grease
- Speed Rating (Sealed): 50–60% of open bearing rating
High-Precision Miniature Ball Bearing
High Precision Low Vibration
Precision-grade miniature bearings manufactured to tighter dimensional and geometric tolerances, delivering superior running accuracy, reduced vibration, and minimal noise for sensitive instrumentation and medical applications.
- Precision Grades: P6, P5, P4, P2 (ABEC 3, 5, 7, 9)
- Radial Runout (P5): ≤3 μm
- Radial Runout (P4): ≤2 μm
- Cage Options: Pressed steel, PEEK polymer, phenolic resin
- Available Series: 600, 618, 619, F600
- Special Lubrication: Vacuum-degassed, low-torque instrument grease available
Applications
RC Models, Drones & Small Motors
High-speed miniature bearings enabling smooth, reliable rotation in brushless motors, servo systems, and drone propulsion units.
Medical & Laboratory Equipment
Precision miniature bearings for dental handpieces, centrifuges, infusion pumps, and laboratory instruments requiring low noise and contamination-free operation.
Office & Consumer Electronics
Compact bearing solutions for printers, scanners, hard drives, and small home appliances requiring quiet, maintenance-free, long-life performance.
Robotics & Automation
Lightweight, high-precision miniature bearings for robot finger joints, servo axes, encoders, and small linear actuators in collaborative robotics.
About BOM Bearing
BOM Bearing is a professional manufacturer and supplier of high-quality miniature deep groove ball bearings, delivering precise and reliable solutions for instruments, electronics, medical, and robotics applications worldwide.
- Quality Assurance: ISO 9001 certified manufacturing process with strict quality control at every production stage
- Miniature Expertise: Full range from 6 mm bore across standard 600, thin-wall 618/619, flanged, and precision series
- Custom Solutions: Tailored options including special clearances, precision grades (ABEC 1–9), cage materials (PEEK, phenolic), and instrument lubricants
- Technical Support: Professional engineering team for product selection, application analysis, and troubleshooting
- Fast Delivery: Efficient production and global logistics network ensuring timely delivery
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Frequently Asked Questions (FAQ)
What is the difference between the 600, 618, and 619 miniature series?
They differ in cross-section size for the same bore diameter. The 618 has the smallest OD and width (extra-light), making it ideal for space-critical designs. The 619 has a slightly larger section with better load capacity. The standard 600 series has the largest cross-section and highest load rating of the three.
What bore sizes are available for BOM miniature bearings?
BOM manufactures miniature deep groove ball bearings starting from 6 mm bore diameter across all standard series (600, 618, 619) and flanged variants (F600).
When should I choose a flanged miniature bearing?
Flanged bearings are recommended when axial location is required without additional snap rings or housings, when installation space is limited, or when the bearing must be retained in a through-bore from one side only. The flange simplifies assembly and prevents bearing migration under axial loads.
What precision grade do I need for medical or instrumentation applications?
For most medical and instrumentation applications, P5 (ABEC 5) is sufficient. For optical encoders, precision spindles, or surgical instruments requiring very low vibration and runout, P4 (ABEC 7) or P2 (ABEC 9) should be specified. Higher precision grades also benefit from vacuum-degassed instrument greases.
Can BOM provide custom miniature bearings?
Yes, we offer customization including special bore and OD combinations, non-standard widths, PEEK or phenolic cages for chemical resistance, special precision grades, low-outgassing lubricants for vacuum environments, and surface coatings for corrosion resistance.
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