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67 Series
Home Deep Groove Ball Bearings 67 Series

6704-ZZ Extra-Thin Deep Groove Ball Bearing | Double Shielded | 20×27×4 mm

6704-ZZ Extra-Thin Deep Groove Ball Bearing | Double Shielded | 20×27×4 mm

Engineered for extreme space limitations, the 6704-ZZ is a single row thin-section ball bearing that delivers high-speed capabilities in a remarkably compact form. Featuring dual pressed steel shields (ZZ), this 20x27x4 mm component effectively guards against coarse debris while retaining the premium factory lubricant. Its ultra-lightweight architecture is highly sought after for advanced robotics, micro-motors, and precision instrumentation where minimizing rotational mass is essential.

6704-ZZ Deep Groove Ball Bearing 20x27x4 mm | 67 Series – Extra Light | Low Friction

This highly specialized extra-light bearing provides exceptional rotational accuracy without the parasitic drag associated with contact seals. The 6704-ZZ excels in enclosed environments where airborne dust is a factor but maximum RPMs and minimal heat generation are priorities. It acts as a vital pivoting element for miniaturized mechanics, ensuring smooth, continuous performance under light radial loads.

6704-ZZ Extra-Thin Deep Groove Ball Bearing | Double Shielded | 20×27×4 mm

Comprehensive Applications

Ideal for high-speed, low-clearance environments requiring minimal friction and ultra-compact components:

Advanced Robotics & Drones
  • Micro-UAV Gimbal Motors
  • Compact Robotic Finger Joints
  • Small Unmanned Ground Vehicles (SUGVs)
  • Automated Optical Inspection Arms
Consumer Electronics & RC Hobbies
  • High-End RC Car Differentials
  • Custom Mechanical Keyboards (Rotary Encoders)
  • VR Headset Tracking Mechanisms
  • Micro 3D Printer Extruders
Precision Medical & Optical Devices
  • Dental Drill Handpieces
  • Surgical Camera Housings
  • Ophthalmic Measuring Instruments
  • Miniature Laser Scanners
Light Industrial & Textile Machinery
  • High-Speed Yarn Guides
  • Automated Sewing Machine Tensioners
  • Small Format Printing Rollers
  • Compact Money Counting Machines

Key Performance Features

01. Metallic Shielding for Low Torque

Equipped with non-contact steel shields on both sides, the 6704-ZZ achieves significantly lower friction compared to rubber-sealed alternatives. This design promotes rapid acceleration and extended high-speed operation up to 18,000 r/min, preventing overheating in tightly packed enclosures.

02. High-Grade Material Construction

Forged from premium GCr15 Chrome Steel, the raceways and rolling elements undergo precise heat treatment. This results in superior hardness and fatigue resistance, ensuring reliable, vibration-free rotation even in the most demanding miniature applications.

03. Minimalist 4mm Cross-Section

The extra-thin 4mm profile allows engineers to drastically shrink the size of their assemblies. Weighing just around 5 grams, this bearing cuts down on overall device weight, which is a critical advantage for battery-powered portable equipment and aerial drones.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 6700 Series (Ultra-Thin Section)
Basic Designation 6704
Suffix ZZ (Double Steel Shields)
Bore Diameter (d) 20 mm
Outer Diameter (D) 27 mm
Width (B) 4 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material Pressed Steel
Dynamic Load Rating (Cʳ) 0.93 kN
Static Load Rating (C₀ʳ) 0.72 kN
Limiting Speed (Grease) 18,000 r/min
Limiting Speed (Oil) --
Weight (approx.) 0.005 kg (5 grams)

Interchange Part Numbers

Common manufacturer equivalents include:

  • SKF: 61704-2Z
  • NSK: 6704ZZ
  • FAG6704-2Z
  • NTN: 6704ZZ
  • KOYO: 6704-2Z
  • NMB: 6704ZZ

Design & Configuration

Supplied with dual steel shields, the 6704-ZZ is the premier choice for low-friction, high-speed requirements in clean to moderately dusty environments. If your application involves exposure to liquids or heavy particle contamination, this ultra-thin model can also be manufactured with rubber contact seals (6704-2RS). Reach out to our engineering support for guidance on the best closure type for your specific operational demands.

"Select the 6704-ZZ extra-thin bearing for unmatched rotational efficiency, significant weight savings, and dependable high-speed performance in confined spaces."

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