71938 ACD/P4ADBB
71900 Series Super Precision Angular Contact Ball Bearings
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Basic Information
Main Dimensions
Ball & Washer Dimensions
Performance
Materials
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71938 ACD/P4ADBB Bearing Product Overview & Core Advantages
The 71938 ACD/P4ADBB is a precision duplex angular contact ball bearing designed for applications requiring exceptional rigidity and accuracy. This matched back-to-back (DB) arrangement is preloaded to Light / Class B specifications, ensuring superior operational stability and minimal axial/radial runout. Its primary advantage lies in its ability to handle combined loads—significant radial and axial loads in both directions—simultaneously. Manufactured to a P4A tolerance class, this bearing is engineered for high-precision, high-rigidity systems where rotational accuracy is paramount.
71938 ACD/P4ADBB Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71938 | Basic bearing series, indicating a high-precision angular contact design. |
| AC | Angular Contact design with a 25° contact angle. |
| D | Duplex (two bearings in a set). |
| DB | Matched arrangement: Back-to-Back. |
| P4A | Tolerance class denoting very high precision levels for dimensional and running accuracy. |
| Open (Seal Type) | No integral seals, designed for systems with external sealing or controlled environments. |
71938 ACD/P4ADBB Bearing Structural Features & Performance Benefits
High Rigidity & Load Capacity: The duplex back-to-back (DB) arrangement creates a rigid bearing system that effectively resists moment loads. This configuration, combined with the 25° contact angle, provides excellent capability for handling combined radial and axial loads from both directions. The phenolic cage material ensures smooth operation and is suitable for high-speed applications.
Precision Performance: Manufactured to P4A tolerance class with tight dimensional controls (bore and OD tolerance: -0.004mm to 0), this bearing guarantees exceptional running accuracy and minimal vibration. The light preload (Class B) eliminates internal clearance, enhancing system stiffness and positioning accuracy.
High-Speed Capability: The phenolic cage and optimized internal geometry contribute to a high limiting speed of 11,000 rpm, making it suitable for demanding high-speed applications.
Material & Durability: Constructed from chrome steel for both rings and balls, the bearing offers high wear resistance and long service life under demanding operating conditions.
71938 ACD/P4ADBB Bearing Typical Application Areas
The 71938 ACD/P4ADBB is ideally suited for high-precision machinery and systems requiring superior rigidity and accuracy, including:
- Machine Tool Spindles (milling, grinding, and turning centers)
- High-Speed Precision Spindles
- Industrial Pumps and Compressors
- Precision Gearboxes
- Robotic Arm Joints and Precision Rotary Axes
