7021 ACD/HCP4ALDGA
Hybrid Ceramic Super Precision Bearings
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7021 ACD/HCP4ALDGA Bearing Product Overview & Core Advantages
The 7021 ACD/HCP4ALDGA is a high-precision angular contact ball bearing engineered for demanding applications requiring exceptional accuracy and performance. This universally matchable (SU) bearing is designed to accommodate combined loads, particularly excelling under high-speed conditions. Its defining characteristics include a 25° contact angle, an extra light preload (Class A), and a P4A super-precision tolerance class. The combination of a phenolic cage and ceramic balls contributes to lower friction, reduced weight, and superior high-speed capabilities, making it an ideal solution for ultra-precise, high-rigidity spindle systems.
Model Code Breakdown
- 7021: Basic series designation, indicating a 105 mm bore and 160 mm outside diameter.
- ACD: Angular Contact, Double Row design. This signifies the bearing can support combined radial and axial loads from both directions.
- HC: Hybrid Ceramic. Denotes the use of ceramic balls with steel rings, offering advantages in speed, stiffness, and service life.
- P4A: Super Precision Tolerance Class. Specifies extremely tight dimensional and running accuracy tolerances for critical applications.
- A: Extra Light Preload. Indicates a specific internal clearance/preload setting for optimal rigidity and running accuracy.
- LD: Light Duty. A classification related to the cage design and internal configuration.
- GA: Universal Matchable (SU). Designates that the bearing is ground to be mounted in a universal arrangement (face-to-face, back-to-back, or tandem) with another identical bearing without selective assembly.
7021 ACD/HCP4ALDGA Bearing Structural Features & Performance Benefits
High Rigidity and Load Capacity: The double row angular contact design provides high radial and axial rigidity, enabling the bearing to handle significant combined loads effectively. The 25° contact angle is optimized for sustaining substantial axial loads.
Superior High-Speed Performance: The hybrid ceramic construction (ceramic balls with steel rings) and the lightweight phenolic cage drastically reduce centrifugal forces, lower operating temperatures, and allow for a very high limiting speed of 16,250 rpm.
Exceptional Precision and Smooth Operation: Manufactured to P4A super-precision standards, this bearing ensures minimal runout and vibration, which is critical for maintaining accuracy in high-speed spindles. The extra light preload ensures consistent performance and minimal heat generation.
Universal Matchability: The SU (Universal Matchable) feature allows for simplified mounting in pairs or sets to create a preloaded bearing system, enhancing system stiffness and simplifying logistics.
7021 ACD/HCP4ALDGA Bearing Typical Application Areas
This bearing is specifically designed for high-performance machinery where precision, speed, and rigidity are paramount. Key applications include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Grinding Spindles: Internal and external grinding machines.
- High-Frequency Motors and Spindles
- Aerospace and Defense Instrumentation
- Medical Equipment Spindles
