71905 ACDGA/HCP4A
Hybrid Ceramic Super Precision Bearings
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71905 ACDGA/HCP4A Bearing Product Overview & Core Advantages
The 71905 ACDGA/HCP4A is a single-row angular contact ball bearing engineered for ultra-high precision and performance in demanding applications. Positioned in the P4A super-precision tolerance class, it delivers exceptional running accuracy and rotational stability. Its core advantage lies in its ability to support combined loads (simultaneous radial and axial loads) efficiently, thanks to its 25° contact angle. The use of ceramic balls and a phenolic cage enables superior high-speed performance and reduced rotational mass, making it ideal for machine tool spindles and other high-velocity machinery where rigidity and minimal thermal expansion are critical.
71905 ACDGA/HCP4A Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71905 | Basic bearing series and size designation (25mm bore, 42mm OD, 9mm width). |
| AC | Angular Contact design with a 25° contact angle. |
| D | High ball complement design for increased load capacity. |
| GA | Indicates a specific internal clearance and preload grade (Extra light preload / Class A). |
| HCP4A | Defines the tolerance class P4A (higher than ABEC 7) and that the bearing is part of a Universal Matchable (SU) set, allowing for precise preload control when mounted with other bearings from the same set. |
71905 ACDGA/HCP4A Bearing Structural Features & Performance Benefits
- Ceramic Ball & Phenolic Cage Combination: The silicon nitride (Si3N4) ceramic balls significantly reduce centrifugal forces, lower friction, and provide non-conductive properties, enabling higher limiting speeds (53,000 rpm) and operation in electrically sensitive environments. The lightweight phenolic resin cage offers excellent strength and guidance at high speeds, contributing to smooth operation.
- High Rigidity & Load Capacity: The 25° contact angle and high ball complement (D) design provide superior stiffness and the ability to handle significant combined radial and axial loads (Dynamic: 1433 lbf, Static: 855 lbf).
- Super-Precision P4A Tolerance: Manufactured to P4A tolerance class with extremely tight dimensional and running accuracy tolerances (bore/OD: -0.004mm to 0), ensuring minimal vibration and exceptional positional accuracy in the application.
- Universal Matching (SU): This bearing is universally matchable and supplied in sets of 4, allowing for flexible mounting configurations (back-to-back, face-to-face, or tandem) to achieve the exact preload and system rigidity required.
71905 ACDGA/HCP4A Bearing Typical Application Areas
This high-precision, high-speed angular contact bearing is ideally suited for applications demanding the utmost accuracy and speed, including:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Robotics: Arm joints and high-accuracy rotary axes.
- High-Frequency Spindles: PCB drilling and routing machines.
- Medical & Dental Equipment: High-speed handpieces and scanners.
- Aerospace Gyroscopes & Instrumentation: Navigation and control systems.
