71918 ACD/P4AQBCB
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71918 ACD/P4AQBCB
Basic Information
System of measurement
Metric
Weight
2.2 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
90 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
125 mm
Outside diameter tolerance
-0.004mm to 0
Width
72 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
11.112 mm
Ball quantity
26
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
26325 lbf
Radial static load rating
43425 lbf
Limiting speed
15 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Quadruplex Back-to-Back (QBC)
Number of bearings in matched set
4
Universal matching bearing
No (Standard)
Preload
Light / Class B
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
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71918 ACD/P4AQBCB Bearing Product Overview & Core Advantages
The 71918 ACD/P4AQBCB is a precision quadruplex angular contact ball bearing designed for demanding applications requiring exceptional rigidity and load capacity. This matched set of four bearings is arranged in a back-to-back (QBC) configuration, enabling it to withstand complex combined loads—significant radial forces and thrust loads in both directions. Manufactured to P4A tolerance class, it guarantees superior running accuracy and rotational precision. With a light preload (Class B) and factory lubrication, it is ready for immediate installation, offering high reliability and performance in high-speed and high-stiffness environments.
71918 ACD/P4AQBCB Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71918 | Basic bearing series and size designation (90mm bore, 125mm OD). |
| ACD | Angular Contact design with a 25° contact angle. |
| P4A | Indicates a high-precision tolerance class (superior to ABEC 7). |
| QBC | Signifies a Quadruplex (set of 4) Back-to-Back matched arrangement. |
71918 ACD/P4AQBCB Bearing Structural Features & Performance Benefits
- Exceptional Rigidity and Load Capacity: The quadruplex back-to-back arrangement creates an extremely rigid bearing system, capable of handling high radial dynamic load ratings of 26,325 lbf and radial static load ratings of 43,425 lbf. This configuration is ideal for applications with significant moment loads.
- Optimized for High-Speed Operation: The phenolic cage offers low weight and excellent performance at high rotational speeds, contributing to a limiting speed of 15,000 rpm.
- Precision Engineering: The P4A tolerance class ensures minimal runout and vibration, which is critical for the accuracy of machine tools and other precision equipment. The specified bearing dimensions (90mm bore, 125mm OD, 72mm width) are held to tight tolerances for consistent performance.
- Robust Material Construction: Made from chrome steel for both rings and balls, this bearing provides high durability and fatigue resistance. The open seal type allows for optimal lubrication flow in controlled environments.
71918 ACD/P4AQBCB Bearing Typical Application Areas
This high-precision, high-rigidity bearing set is specifically engineered for advanced industrial machinery, including:
- Machine Tool Spindles: For high-speed milling, grinding, and turning centers requiring utmost accuracy and stiffness.
- Precision Gearboxes: Especially in applications involving high torque and complex load conditions.
- High-Frequency Spindles: Used in PCB drilling, semiconductor manufacturing, and other high-RPM processes.
- Industrial Pumps and Compressors: Where reliable performance under combined loads is essential.
