71811 ACD/P4DBC
71800 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71811 ACD/P4DBC
Basic Information
System of measurement
Metric
Weight
0.16 kg
Tolerance class
P4
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
55 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
72 mm
Outside diameter tolerance
-0.004mm to 0
Width
18 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
4.762 mm
Ball quantity
29
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
3510 lbf
Radial static load rating
4590 lbf
Limiting speed
34 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Duplex Back-to-Back (DB)
Number of bearings in matched set
2
Universal matching bearing
No (Standard)
Preload
Moderate / Class C
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
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In Stock
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71811 ACD/P4DBC Bearing Product Overview & Core Advantages
The 71811 ACD/P4DBC is a precision duplex angular contact ball bearing designed for applications requiring exceptional rotational accuracy and rigidity. This matched set features a back-to-back (DB) arrangement and is manufactured to P4 tolerance class, ensuring superior running accuracy. Its primary advantage lies in its ability to support combined loads (radial and axial) simultaneously, making it ideal for high-precision, high-rigidity spindles and other demanding machinery where precise axial positioning is critical.
71811 ACD/P4DBC Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71811 | Basic bearing designation, indicating a metric, angular contact type. |
| AC | Angular Contact design with a 25° contact angle for optimal axial load capacity. |
| D | Indicates a duplex (two-bearing) set. |
| P4 | Specifies the tolerance class, denoting high precision with tight dimensional and running accuracy limits. |
| DB | Specifies the matched arrangement as Back-to-Back (DB). This configuration provides high moment rigidity and is effective for withstanding overturning moments. |
| C | Indicates a Moderate preload (Class C), which enhances system rigidity and minimizes axial and radial runout. |
71811 ACD/P4DBC Bearing Structural Features & Performance Benefits
- High Rigidity & Load Capacity: The back-to-back (DB) duplex arrangement creates a wide effective spread, significantly increasing the bearing set's resistance to moment loads and providing exceptional stiffness. The 25° contact angle is optimized to handle substantial combined radial and axial loads.
- Precision Performance: Manufactured to P4 tolerance class, this bearing ensures minimal runout and vibration, which is critical for applications requiring high rotational accuracy.
- Optimized High-Speed Capability: The phenolic resin cage is lightweight and possesses excellent sliding properties, contributing to lower friction, reduced heat generation, and stable operation at the limiting speed of 34,000 rpm.
- Ready-to-Install Matched Set: Supplied as a pre-matched duplex pair, the bearings are selectively assembled to maintain precise preload and alignment, simplifying installation and ensuring consistent, reliable performance.
71811 ACD/P4DBC Bearing Typical Application Areas
This precision bearing set is engineered for high-performance applications, including:
- Machine Tool Spindles (e.g., for milling, grinding, and turning centers)
- High-Frequency Spindles
- Precision Gearboxes
- Robotic Drives and Rotary Joints
- Medical and Dental Equipment Spindles
