W 638/4 R-2Z
W Series Stainless Steel Flanged Miniature Bearings
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Part No.
Part No.
W 638/4 R-2Z
Basic Information
Bearing type
Ball
System of measurement
Metric
Construction
Single Row
Weight
0.0011 kg
Tolerance class
P0
Seal type
Shielded
For load direction
Radial
Main Dimensions
Bore diameter
4 mm
Bore diameter tolerance
-0.008mm to 0
Outside diameter
9 mm
Outside diameter tolerance
-0.008mm to 0
Width
4 mm
Width tolerance
-0.12mm to 0
Outer Ring Dimensions
Flange outer diameter
10.3 mm
Flange thickness
1 mm
Performance
Temperature range
-30° to 120 °C
Radial dynamic load rating
82 lbf
Radial static load rating
26 lbf
Limiting speed
70 X 1000 rpm
Lubrication
Grease
Radial internal clearance
CN
Materials
Ring material
Stainless Steel
Ball material
Stainless Steel
Cage material
Stainless Steel
Environment & Compliance
REACH
Compliant
ROHS
Compliant
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
Price available upon request.
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W 638/4 R-2Z Bearing Product Overview & Core Advantages
The W 638/4 R-2Z is a metric miniature deep groove ball bearing designed for applications demanding compact size, high precision, and reliable performance in challenging environments. Its single row construction with stainless steel components offers excellent corrosion resistance. A key feature is the inclusion of shielded seals (2Z) on both sides, which effectively retain factory-applied grease lubrication and protect against contaminants, making it a robust, low-maintenance solution for radial loads. This bearing is ideal for high-speed, precision mechanisms where space is limited and reliability is critical.
W 638/4 R-2Z Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning | Significance & Advantage |
|---|---|---|
| W 638/4 | Basic bearing designation indicating a specific miniature deep groove ball bearing series with a 4 mm bore. | Identifies the core bearing dimensions and series, ensuring proper fit and interchangeability. |
| R | Flanged outer ring. | Enables simplified axial location and secure mounting within a housing, enhancing assembly accuracy and rigidity. |
| 2Z | Non-contact shields on both sides of the bearing. | Provides effective protection against contamination while retaining lubricant, contributing to the bearing's maintenance-free and long-service-life characteristics. Minimizes friction loss compared to contact seals. |
W 638/4 R-2Z Bearing Structural Features & Performance Benefits
- All-Stainless-Steel Construction: The rings, balls, and cage are manufactured from stainless steel, providing superior corrosion resistance and making the bearing suitable for use in humid, washdown, or chemically aggressive environments.
- Flanged Design for Enhanced Rigidity: The integral flange on the outer ring simplifies mounting and positioning, increasing system stiffness and stability, which is crucial for the precise alignment of miniature assemblies.
- Optimized for High-Speed Operation: The non-contact 2Z shields and precision-ground components result in low friction torque, allowing for a high limiting speed of 70,000 rpm, ideal for high-speed small motors and spindles.
- Pre-Greased and Sealed for Longevity: Factory-applied grease and shielded seals create a sealed-for-life unit, reducing maintenance needs and ensuring consistent performance across the specified temperature range of -30°C to 120°C.
- Standard Internal Clearance and Tolerance: Supplied with CN group radial internal clearance and P0 tolerance class, offering a balance of running quietness and thermal expansion management for most general applications.
W 638/4 R-2Z Bearing Typical Application Areas
This miniature flanged bearing is engineered for compact, high-speed devices across various industries:
- Small Precision Motors: Used in stepper motors, DC micromotors, and spindle motors for drones, medical devices, and optical drives.
- Office Automation Equipment: Ideal for printers, scanners, and copiers where reliable, quiet operation is essential.
- Instrumentation and Control Systems: Supports shafts in encoders, sensors, and small gearboxes requiring high positional accuracy.
- Medical and Dental Handpieces: Suitable for high-speed rotary tools due to its corrosion resistance and ability to handle rapid rotations.
- Robotics and RC Models: Provides durable and precise rotation in joints, wheels, and small drive systems.
