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MR Series
Home Deep Groove Ball Bearings MR Series

MR74-ZZ Shielded Miniature Ball Bearing For Precision Micro-Mechanics | Dual Metal Shields | 4×7×2.5 mm

MR74-ZZ Shielded Miniature Ball Bearing For Precision Micro-Mechanics | Dual Metal Shields | 4×7×2.5 mm

The MR74-ZZ is a high-performance miniature ball bearing crafted for ultra-compact systems where frictionless rotation and foundational particulate defense are paramount. Fitted with dual non-contact pressed steel shields (ZZ), this 4x7x2.5 mm component creates a reliable safeguard against large dust particles while eliminating the drag associated with rubber seals. Its low-friction profile is specifically engineered for high-speed micro-motors, precision instruments, and robotics, ensuring internal raceways are kept clean and the specialized lubricant is securely housed for an extended operational lifespan.

MR74-ZZ Deep Groove Ball Bearing 4x7x2.5 mm | MR Series – Low Friction & High Velocity

Purpose-built to deliver exceptional RPM capabilities alongside structural integrity, this metal-shielded micro-bearing performs flawlessly in high-velocity applications. The MR74-ZZ utilizes twin steel shields that hover just above the inner ring's shoulder, keeping out dirt without generating mechanical drag. This frictionless shielding enables a stellar rotational threshold of 60,000 r/min when lubricated with grease, and up to 67,000 r/min with oil. It acts as an ultra-efficient rotary pivot for delicate mechanical setups, granting silent, vibration-free operation and sustained reliability.

MR74-ZZ Shielded Miniature Ball Bearing For Precision Micro-Mechanics | Dual Metal Shields | 4×7×2.5 mm

Comprehensive Applications

Catering to designers and technicians assembling miniature, high-RPM devices that prioritize low running torque over watertight sealing:

Robotics & Micro-Automation
  • Micro Servo Motors
  • Precision Rotary Encoders
  • Miniature Articulated Robotic Joints
  • Automated Optical Gimbals
Precision Instruments & Electronics
  • Hard Disk Drive Spindles
  • Laser Scanner Motors
  • Micro Cooling Fans
  • High-Speed Dental Handpieces
Hobbyist Engineering & RC Models
  • Brushless RC Motors
  • 1/24 Scale RC Car Gearboxes
  • Mini Quadcopter Propeller Shafts
  • 3D Printer Extruder Mechanisms
Office & Commercial Equipment
  • Compact Card Readers
  • High-Speed Paper Feed Rollers
  • Currency Counting Machines
  • Precision Stepper Motors

Key Performance Features

01. Premium GCr15 Chrome Steel Construction

Manufactured using elite GCr15 Chrome Steel for both the raceways and balls, this bearing is subjected to precise thermal treatments. This yields an exceptionally hard, fatigue-resistant core that effortlessly withstands continuous, high-RPM stress, holding strict P5 or P6 precision tolerances for demanding assemblies.

02. Dual Non-Contact Steel Shielding (ZZ)

Enclosed by high-quality pressed steel shields on both sides, the MR74-ZZ offers robust protection against solid contaminants. Because these shields do not physically contact the inner ring, they generate zero additional rotational torque, making them the optimal choice for high-speed, low-power applications where efficiency is critical.

03. Ultra-Compact 4mm Bore Design

With an internal diameter of 4mm and a mere 7mm outer diameter, the MR74-ZZ offers extreme space-saving potential without sacrificing stability. The 2.5mm width ensures adequate load distribution, while its feather-light weight (roughly 0.29 grams) is indispensable for weight-critical, fast-moving portable devices.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series MR Series (Miniature Metric)
Basic Designation MR74
Suffix ZZ (Dual Pressed Steel Shields)
Bore Diameter (d) 4 mm
Outer Diameter (D) 7 mm
Width (B) 2.5 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material Pressed Steel
Dynamic Load Rating (Cʳ) 0.310 kN (310 N)
Static Load Rating (C₀ʳ) 0.115 kN (115 N)
Limiting Speed (Grease) 60,000 r/min
Limiting Speed (Oil) 67,000 r/min
Weight (approx.) 0.00029 kg (0.29 grams)

Interchange Part Numbers

Commonly cross-referenced manufacturer equivalents used by procurement specialists:

  • SKF: MR74-2Z
  • NMBL-740ZZ
  • NSK: MR74ZZ
  • NTN: MR74 ZZ
  • FAG: MR74-2Z
  • KOYO: MR74 ZZ

Design & Configuration

Secured by twin metal shields, the MR74-ZZ stands as the ultimate hardware for projects requiring frictionless velocity and a maintenance-free lifecycle. Even at maximum RPM, the non-contact shielding ensures heat generation remains minimal while protecting the rolling elements. Backed by over 15 years of dedicated deep groove ball bearing manufacturing and research, Welink Bearing delivers this component with customizable lubrication and internal clearance variables (such as C3) to precisely align with your industrial motor specifications.

"Integrate the MR74-ZZ shielded miniature bearing to achieve frictionless high-speed performance, optimal thermal management, and reliable precision in your most compact mechanical designs."

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