71903 ACD/P4AQBCD
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71903 ACD/P4AQBCD
Basic Information
System of measurement
Metric
Weight
0.068 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
17 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
30 mm
Outside diameter tolerance
-0.004mm to 0
Width
28 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
3.969 mm
Ball quantity
14
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
2385 lbf
Radial static load rating
1800 lbf
Limiting speed
121 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
Heavy / Class D
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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71903 ACD/P4AQBCD Bearing Product Overview & Core Advantages
The 71903 ACD/P4AQBCD is a precision angular contact ball bearing designed for applications demanding exceptional rigidity and accuracy. As part of a Quadruplex Back-to-Back (QBC) matched set, this bearing is engineered to handle significant combined loads (radial and axial) simultaneously. Its P4A tolerance class and Heavy preload (Class D) ensure superior rotational accuracy and minimal runout, making it ideal for high-precision, high-stiffness machinery where positional stability is critical.
71903 ACD/P4AQBCD Bearing Model Code Explained, Specifications & Naming Convention
The model number 71903 ACD/P4AQBCD is decoded as follows:
- 71903: Basic bearing series, indicating a metric, angular contact design with a 17mm bore, 30mm OD, and 28mm width.
- ACD: Angular Contact design with a D (25°) contact angle.
- P4A: Denotes an ultra-precision tolerance class, superior to ABEC 7, ensuring extremely tight dimensional and running accuracy.
- QBC: Specifies the bearing is part of a Quadruplex Back-to-Back matched set, consisting of 4 bearings arranged for maximum rigidity.
- D: Indicates a Heavy preload (Class D) applied to the set, minimizing axial and radial play under operating conditions.
71903 ACD/P4AQBCD Bearing Structural Features & Performance Benefits
- High Rigidity & Load Capacity: The Quadruplex Back-to-Back (QBC) arrangement provides exceptional system stiffness, enabling the bearing to withstand heavy combined loads and moments. The 25° contact angle and Heavy preload further enhance axial load capacity and resistance to deflection.
- Precision Performance: Manufactured to P4A tolerance class, this bearing guarantees minimal runout and vibration, which is crucial for applications requiring high rotational accuracy.
- High-Speed Capability: The phenolic cage offers low mass and excellent performance at high speeds, contributing to the bearing's limiting speed of 121,000 rpm. The open design and factory lubrication are optimized for these demanding conditions.
- Durable Construction: Components made from chrome steel provide high hardness and fatigue resistance, ensuring long service life under heavy loads and in a wide temperature range (-30°C to 110°C).
71903 ACD/P4AQBCD Bearing Typical Application Areas
This high-precision, preloaded quadruplex set is typically used in:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers requiring extreme rigidity and accuracy.
- Precision Rotary Systems: Industrial robots, indexing tables, and high-performance automation equipment.
- Medical & Laboratory Equipment: Centrifuges and advanced imaging systems where smooth, precise rotation is mandatory.
- Aerospace & Defense Systems: Gyroscopes, radar platforms, and other critical guidance and positioning mechanisms.
