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67 Series
Home Deep Groove Ball Bearings 67 Series

6702-ZZ Ultra-Thin Section Ball Bearing | 15×21×4 mm for Drones & Precision Instruments

6702-ZZ Ultra-Thin Section Ball Bearing | 15×21×4 mm for Drones & Precision Instruments

The 6702-ZZ is a specialized, ultra-lightweight deep groove ball bearing engineered for modern applications that demand minimal spatial footprint and maximum rotational efficiency. Featuring dual non-contact metal shields (ZZ), this model effectively retains premium factory grease while delivering significantly lower rotational friction than standard rubber-sealed variants. Measuring 15mm on the bore, an outer diameter of 21mm, and a remarkably slim 4mm width, the 6702-ZZ is an essential component for UAV mechanisms, gimbal stabilizers, and sophisticated medical devices where consistent, low-torque operation is critical.

6702-ZZ Deep Groove Ball Bearing 15x21x4 mm | Metric Extra-Thin Series | Double Metal Shielded

Manufactured strictly to international ISO tolerances, the 6702-ZZ leverages an extra-thin cross-section to deliver robust radial load support within extremely constrained design envelopes. The twin pressed-steel shields act as a protective barrier against external particulate ingress without adding physical drag to the inner ring, thereby preserving the bearing's exceptional high-RPM capabilities. This makes it an outstanding choice for maintenance-free environments requiring long-term reliability and minimal thermal expansion, such as precision robotics and optical tuning assemblies.

6702-ZZ Ultra-Thin Section Ball Bearing | 15×21×4 mm for Drones & Precision Instruments

Comprehensive Applications

Tailored for ultra-compact mechanical systems and low-drag, high-speed rotation:

UAVs & RC Vehicles
  • Drone propeller shafts and micro-motor assemblies
  • RC helicopter rotor heads and swashplates
  • Micro-gimbal camera mounts and stabilization arms
  • High-performance hobby racing chassis
High-Precision Robotics
  • Micro-actuator assemblies and miniature gearboxes
  • Robotic finger joints and articulated links
  • Compact rotary encoder housings
  • Automated pick-and-place machine components
Medical & Laboratory Instruments
  • Handheld diagnostic tools and scanners
  • Centrifuge spinner components
  • Automated liquid handling and pipetting systems
  • Dental and surgical rotary instruments
Optics & Office Tech
  • Camera lens focus rings and zoom mechanisms
  • Precision measuring tools and surveying equipment
  • Laser scanner mirrors and high-speed stepper motors
  • Banknote counting machines and microfilm readers

Key Performance Features

01. Minimized Friction for Peak RPM

By utilizing two metal shields (ZZ) that avoid physical contact with the inner raceway, the 6702-ZZ guarantees an ultra-low drag coefficient. This non-contact sealing strategy allows for superior high-speed acceleration and lower starting torque, which is highly advantageous for battery-powered electronics and micro-motors where energy conservation is paramount.

02. Ultra-Thin Space-Saving Design

With a total width of just 4mm and an exceptionally narrow cross-sectional profile, the 6700-series empowers engineers to dramatically reduce the weight and size of their housings. Despite its diminutive scale, the precision-honed deep-groove geometry reliably accommodates radial loads and light axial loads in both directions, delivering an excellent power-to-weight ratio.

03. High-Grade GCr15 Chrome Steel

Forged from premium vacuum-degassed 52100 (GCr15) chrome steel, these bearings undergo advanced heat treatment to achieve superior Rockwell hardness and fatigue resistance. Pre-lubricated with high-performance, temperature-stable grease, the 6702-ZZ provides prolonged service life, structural integrity, and smooth acoustics right out of the box.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 6700 Series (Extra-Thin Section)
Basic Designation 6702
Suffix ZZ (Double Steel Shields)
Bore Diameter (d) 15 mm
Outer Diameter (D) 21 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) 0.936 kN
Static Load Rating (C₀ʳ) 0.582 kN
Limiting Speed (Grease) 28,000 r/min
Limiting Speed (Oil) 34,000 r/min
Weight (approx.) 0.0035 kg

Interchange Part Numbers

Direct cross-reference replacements for major global brands:

  • SKF: 6702-2Z
  • NSK: 6702ZZ
  • FAG: 6702-2Z
  • NTN: 6702ZZ
  • KOYO: 6702ZZ
  • EZO: 6702ZZ

Design & Configuration

The standard 6702-ZZ is supplied with multipurpose high-speed grease. For specialized industrial needs, Welink Bearing can supply this model with C3 internal clearance for elevated temperature zones, or in AISI 440C stainless steel (S6702-ZZ) for corrosive and moisture-rich environments. If your design faces liquid splashing or heavy dust, the contact-sealed 6702-2RS is also available upon request.

"The 6702-ZZ extra-thin bearing delivers an unmatched combination of space efficiency and friction reduction, driving innovation in modern micro-mechanics and aerospace technologies."

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6702-ZZ Ultra-Thin Section Ball Bearing 15x21x4 mm displaying dual pressed steel shields for low-friction rotation
6702-ZZ Ultra-Thin Section Ball Bearing | 15×21×4 mm for Drones & Precision Instruments

The 6702-ZZ is a specialized, ultra-lightweight deep groove ball bearing engineered for modern applications that demand minimal spatial footprint and maximum rotational efficiency. Featuring dual non-contact metal shields (ZZ), this model effectively retains premium factory grease while delivering significantly lower rotational friction than standard rubber-sealed variants. Measuring 15mm on the bore, an outer diameter of 21mm, and a remarkably slim 4mm width, the 6702-ZZ is an essential component for UAV mechanisms, gimbal stabilizers, and sophisticated medical devices where consistent, low-torque operation is critical.

Details

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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.
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