71956 ACD/P4AQBCC
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71956 ACD/P4AQBCC
Basic Information
System of measurement
Metric
Weight
51.6 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
280 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
380 mm
Outside diameter tolerance
-0.004mm to 0
Width
184 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
30.162 mm
Ball quantity
31
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
163800 lbf
Radial static load rating
389250 lbf
Limiting speed
7.5 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
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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71956 ACD/P4AQBCC Bearing Product Overview & Core Advantages
The 71956 ACD/P4AQBCC is a precision angular contact ball bearing designed for demanding applications requiring exceptional rigidity and accuracy. This bearing is supplied as a Quadruplex Back-to-Back (QBC) matched set, delivering superior stiffness and the ability to handle significant combined loads (radial and axial). Manufactured to a P4A tolerance class and featuring a moderate preload (Class C), it is engineered for high-performance scenarios where rotational precision and operational reliability are paramount. Its robust construction and matched arrangement make it ideal for complex spindle systems.
71956 ACD/P4AQBCC Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71956 | Basic bearing series and size designation. |
| AC | Angular Contact design with a 25° contact angle. |
| D | Signifies a moderate preload (Class C). |
| P4A | Indicates a high precision tolerance class, exceeding ABEC 7/ISO P4 standards. |
| QBCC | Specifies the bearing is part of a Quadruplex Back-to-Back (QBC) matched set. |
71956 ACD/P4AQBCC Bearing Structural Features & Performance Benefits
- Exceptional Rigidity and Load Capacity: The Quadruplex Back-to-Back (QBC) arrangement of four bearings creates an extremely rigid system, capable of supporting high radial dynamic load ratings of 163,800 lbf and radial static load ratings of 389,250 lbf. This configuration is optimized to handle heavy combined loads.
- Precision Performance: Manufactured to P4A tolerance class with tight dimensional controls on the bore diameter (280 mm) and outside diameter (380 mm), ensuring minimal runout and smooth, precise operation.
- Optimized High-Speed Operation: The phenolic cage is lightweight and robust, contributing to stable operation at the bearing's limiting speed of 7,500 rpm. The 25° contact angle provides an excellent balance for axial load capacity and speed.
- Durable Construction: Components made from chrome steel for both rings and balls offer high wear resistance and long service life. The bearing comes pre-lubricated for immediate installation and initial operation.
71956 ACD/P4AQBCC Bearing Typical Application Areas
This bearing is engineered for high-precision, high-stiffness machinery, including:
- Machine Tool Spindles (e.g., for milling, grinding, and turning centers)
- High-Speed Machining Centers
- Precision Gearboxes
- Industrial Pumps and Compressors
- Other applications requiring a matched bearing set for superior rigidity and accuracy.
