W 638/4-2Z
W Series Stainless Steel Miniature Bearings
Image may differ from product. See technical specification for details.
Part No.
Part No.
W 638/4-2Z
Basic Information
Bearing type
Ball
System of measurement
Metric
Construction
Single Row
Weight
0.000925 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
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
Price:
$ 2.12
/ each
In Stock
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W 638/4-2Z Bearing Product Overview & Core Advantages
The W 638/4-2Z is a metric single row deep groove ball bearing designed for exceptional performance in compact applications. Engineered with stainless steel construction throughout (rings, balls, and cage), it offers superior corrosion resistance. Its key advantage lies in its ability to handle radial loads efficiently while being shielded (2Z) and pre-lubricated for long-term, maintenance-free operation. This makes it an ideal precision bearing for applications demanding high reliability, cleanliness, and a compact footprint.
Model Code Breakdown
| Code Segment | Technical Meaning |
|---|---|
| W 638/4 | Basic bearing series designation with a 4 mm bore diameter. |
| 2Z | Signifies the bearing is equipped with non-contact shields on both sides. This provides effective protection against contamination while minimizing friction, contributing to the high limiting speed. |
W 638/4-2Z Bearing Structural Features & Performance Benefits
- Robust Stainless Steel Construction: All components (rings, balls, cage) are made from stainless steel, providing excellent corrosion resistance and making the bearing suitable for harsh environments and applications requiring washdown.
- Effective Contamination Protection: The non-contact 2Z shields protect the bearing interior from dust and other particulates, significantly extending service life and enabling maintenance-free operation.
- Optimized for High Speeds: The combination of a low-friction stainless steel cage, shielded design, and factory-applied grease allows for a high limiting speed of 70,000 rpm.
- Ready-to-Use & Long-Lasting: The bearing is pre-lubricated with grease and features a standard CN radial internal clearance, making it immediately operational upon installation over a wide temperature range of -30°C to 120°C.
W 638/4-2Z Bearing Typical Application Areas
- Small Precision Electric Motors
- Medical and Dental Handpieces
- Office Automation Equipment (e.g., printers, scanners)
- Instrumentation and Control Devices
- Small Fans and Pumps
- Robotics and Miniature Drives
