71821 ACD/P4
71800 Series Super Precision Angular Contact Ball Bearings
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Main Dimensions
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71821 ACD/P4 Bearing Product Overview & Core Advantages
The 71821 ACD/P4 is a single-row angular contact ball bearing engineered for high-precision applications requiring exceptional rotational accuracy and rigidity. This P4 (ABEC-7) tolerance class bearing is designed to accommodate high combined loads, primarily thrust loads in one direction, with a 25° contact angle that optimizes load capacity and high-speed performance. Its compact design, featuring a 13 mm width, makes it ideal for space-constrained, high-reliability machinery. The bearing is pre-lubricated and features a phenolic cage, contributing to its high-speed capability and stable operation.
71821 ACD/P4 Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning | Significance |
|---|---|---|
| 71821 | Basic bearing designation | Defines the standard metric dimensions: 105 mm bore, 130 mm OD, 13 mm width. |
| AC | Angular Contact design | Optimized for combined radial and axial loads with a defined contact angle. |
| D | High Contact Angle (25°) | Provides higher thrust load capacity, suitable for applications with significant axial forces. |
| P4 | Tolerance Class (ABEC-7) | Indicates ultra-precision manufacturing with extremely tight dimensional and running accuracy tolerances for superior performance. |
71821 ACD/P4 Bearing Structural Features & Performance Benefits
High Rigidity and Precision: Manufactured to P4 precision class, this bearing ensures minimal runout and vibration, which is critical for applications demanding high positional accuracy. The phenolic resin cage offers excellent dimensional stability and low friction, contributing to smooth operation at the limiting speed of 12,000 rpm.
Superior Load Capacity: The 25° contact angle and robust construction using chrome steel for rings and balls enable it to handle high dynamic and static load ratings (4860 lbf / 6412 lbf). It is ideally suited for applications with significant axial loads in one direction.
Optimized for High-Speed Operation: The combination of the lightweight phenolic cage, precision-ground components, and pre-lubrication allows for high rotational speeds with minimal heat generation and wear.
Open Design with Pre-lubrication: The open seal type facilitates relubrication if required in specific service conditions. The bearing comes pre-lubricated for immediate use, ensuring quick startup and initial protection.
71821 ACD/P4 Bearing Typical Application Areas
The 71821 ACD/P4 is a critical component in high-performance machinery where precision and speed are paramount. Key application areas include:
- Machine Tool Spindles: For high-speed milling, grinding, and turning centers requiring extreme accuracy.
- Precision Gearboxes and Transmission Systems: Where high rigidity and load capacity are needed.
- High-Frequency Motors and Spindles: In applications demanding low vibration and high rotational speeds.
- Aerospace and Defense Actuation Systems: For reliable performance in critical control mechanisms.
- Medical and Laboratory Equipment: Such as high-speed centrifuges and precision instruments.
