71909 ACD/P4ADBC
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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71909 ACD/P4ADBC Bearing Product Overview & Core Advantages
The 71909 ACD/P4ADBC is a precision duplex angular contact ball bearing designed for applications requiring exceptional rigidity and accuracy. This metric bearing features a back-to-back (DB) matched arrangement with a Moderate (Class C) preload, enabling it to handle significant combined loads—both radial and axial—simultaneously. Its P4A tolerance class ensures superior running accuracy, making it ideal for high-speed, high-precision machinery where stability and reliability are paramount.
71909 ACD/P4ADBC Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71909 | Basic bearing series and size designation (45mm bore, 68mm OD). |
| AC | Angular Contact design with a 25° contact angle. |
| D | Indicates the bearing is part of a Duplex (matched) set. |
| P4A | High Precision Tolerance Class, specifying very tight dimensional and running accuracy. |
| DB | Back-to-Back arrangement of the matched set, providing high moment rigidity. |
| C | Specifies a Moderate Preload (Class C) applied to the matched set. |
71909 ACD/P4ADBC Bearing Structural Features & Performance Benefits
Optimized Internal Geometry & Material Selection: Constructed from chrome steel for both rings and balls, this bearing offers high durability and wear resistance. The phenolic resin cage is lightweight and robust, contributing to smooth operation at the high limiting speed of 41,000 rpm.
Superior Rigidity and Load Capacity: The back-to-back duplex arrangement significantly increases system rigidity, effectively resisting moment loads. With a 25° contact angle, it is engineered to support substantial combined radial and axial loads (Dynamic: 4478 lbf, Static: 4050 lbf).
Precision and Speed Performance: The P4A tolerance class ensures minimal runout and vibration, which is critical for precision applications. The combination of precision grinding, optimized internal clearance with preload, and the phenolic cage enables reliable high-speed operation.
Ready-to-Install Performance: The bearing is supplied lubricated and as a pre-matched set, ensuring consistent performance and simplifying the installation process for critical spindle assemblies.
71909 ACD/P4ADBC Bearing Typical Application Areas
- Machine Tool Spindles: High-speed milling, grinding, and turning centers requiring extreme precision and rigidity.
- Precision Grinding Spindles: Applications where low vibration and high running accuracy are non-negotiable.
- High-Frequency Motors: Spindles for PCB drilling and other high-RPM electric motors.
- Industrial Pumps and Compressors: For shafts subjected to significant combined loads.
- Robotic Arm Joints and Precision Rotary Tables: Where accurate positioning and high moment stiffness are required.
