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MR Series
Home Deep Groove Ball Bearings MR Series

MR74-2RS Sealed Miniature Ball Bearing For Harsh Environments | Dual Rubber Seals | 4×7×2.5 mm

MR74-2RS Sealed Miniature Ball Bearing For Harsh Environments | Dual Rubber Seals | 4×7×2.5 mm

The MR74-2RS is a precision-engineered miniature bearing designed for applications where high-level sealing is required within an ultra-slim footprint. Equipped with dual synthetic rubber contact seals (2RS), this 4x7x2.5 mm component creates an airtight barrier that effectively blocks out moisture, fine dust, and liquid splashes. Its compact profile is specifically optimized for outdoor electronics, waterproof servos, and medical handpieces, ensuring that the internal components remain lubricated and shielded even in contaminated or humid operating conditions.

MR74-2RS Deep Groove Ball Bearing 4x7x2.5 mm | MR Series – Maximum Protection & Durability

Designed to bridge the gap between high-speed rotation and environmental resilience, this sealed micro-bearing excels where exposure to the elements is a concern. The MR74-2RS utilizes reinforced NBR rubber seals that maintain a constant light-pressure contact with the inner ring, preventing lubricant leakage and contaminant ingress. This configuration supports a reliable limiting speed of 50,000 r/min under grease lubrication and up to 59,000 r/min if the seals are removed for oil-run applications. It serves as a rugged rotary solution for micro-mechanics, providing smooth motion and exceptional wear resistance.

MR74-2RS Sealed Miniature Ball Bearing For Harsh Environments | Dual Rubber Seals | 4×7×2.5 mm

Comprehensive Applications

Catering to engineering requirements for ultra-compact, high-protection mechanical components in demanding sectors:

Outdoor Robotics & Drone Technology
  • Waterproof Micro Servo Motors
  • Miniature Underwater ROV Thrusters
  • Compact Outdoor Surveillance Gimbals
  • Weather-Resistant Sensing Equipment
Medical & Laboratory Devices
  • Portable Infusion Pump Motors
  • Miniature Surgical Power Drills
  • Diagnostic Laboratory Stirrers
  • Handheld Dental Cleaning Tools
RC Models & Micro-Vehicles
  • Sealed RC Crawler Differential Bearings
  • Mini-Z Racing Car Hub Bearings
  • Precision Steering Linkage Pivots
  • Waterproof Brushless Motor Outrunners
Consumer Electronics & Smart Home
  • Smart Lock Rotating Mechanisms
  • Electric Toothbrush Drive Shafts
  • Compact Humidifier Fan Motors
  • High-End Kitchen Appliance Controls

Key Performance Features

01. Dual Rubber Contact Sealing (2RS)

The MR74-2RS features high-grade NBR rubber seals on both faces. This contact technology provides the highest level of shielding against liquids and microscopic particles, making it the premier choice for devices used in non-sterile or exposed outdoor environments.

02. High-Hardness GCr15 Chrome Steel

Utilizing premium GCr15 Chrome Steel for the inner/outer rings and balls, this bearing undergoes advanced heat treatment for superior hardness. This ensures the bearing maintains its P5/P6 precision grade under heavy loads, resisting surface fatigue and extending the service life of sensitive assemblies.

03. Micro 4mm Bore for Space Optimization

With a 4mm bore and a mere 7mm outer diameter, the MR74-2RS allows for significant miniaturization of shafts and housings. Its 2.5mm width and feather-light weight (approx. 0.31 grams) are critical for battery-powered, weight-sensitive portable devices that cannot compromise on protection.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series MR Series (Miniature Metric)
Basic Designation MR74
Suffix 2RS (Dual Rubber Contact Seals)
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
Seal Material Synthetic Rubber (NBR)
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) 59,000 r/min (Seals removed)
Weight (approx.) 0.00031 kg (0.31 grams)

Interchange Part Numbers

Cross-referenced manufacturer equivalents for technical procurement:

  • SKF: MR74-2RS1
  • NMB: L-740LL
  • NSK: MR74 DDU
  • NTN: MR74 LLU
  • FAG: MR74-2RSR
  • KOYO:MR74-2RS

Design & Configuration

Equipped with dual contact rubber seals, the MR74-2RS is the definitive choice for maintenance-free operation in micro-scale engineering. While the seals provide maximum defense, the internal geometry is fine-tuned to maintain high efficiency in high-torque micro-motors. With over 15 years of technical manufacturing expertise, Welink Bearing offers custom clearance (such as C3) and specialized grease options to ensure your compact designs perform reliably in any climate.

"Integrate the MR74-2RS sealed miniature bearing to achieve maximum environmental defense and superior lubricant retention in your most compact mechanical assemblies."

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