7028 CD/HCP4A
Hybrid Ceramic Super Precision Bearings
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7028 CD/HCP4A Bearing Product Overview & Core Advantages
The 7028 CD/HCP4A is a high-precision angular contact ball bearing engineered for demanding applications requiring exceptional accuracy and performance. This single bearing features a 15° contact angle and is supplied with a preload, delivering high system rigidity, precise rotational accuracy, and excellent running stability. Its construction with a phenolic cage and ceramic balls makes it an ideal solution for high-speed operation, significantly reducing centrifugal forces and managing thermal expansion. The bearing is pre-lubricated for immediate use and is capable of handling combined radial and axial loads simultaneously.
Model Code Breakdown
| Code Segment | Technical Meaning |
|---|---|
| 7028 | Basic bearing designation indicating a 140 mm bore, 210 mm outside diameter, and 33 mm width. |
| CD | Indicates a high-precision, duplexed bearing arrangement with a specific preload. |
| HCP4A | Denotes the tolerance class P4 (ABEC-7) and specific internal design features for optimal performance. |
7028 CD/HCP4A Bearing Structural Features & Performance Benefits
- High Rigidity and Precision: The 15° contact angle and applied preload ensure high system stiffness and minimal deflection under load, which is critical for maintaining precision in machining and positioning.
- Superior High-Speed Capability: The combination of a lightweight phenolic resin cage and low-density ceramic (silicon nitride) balls reduces centrifugal forces and friction, enabling a high limiting speed of 12,000 rpm.
- Enhanced Load Capacity: Designed to support significant combined loads, with a high dynamic load rating of 34,425 lbf and static load rating of 37,350 lbf.
- Optimized Thermal Performance: Ceramic balls have a lower coefficient of thermal expansion than steel, contributing to stable preload and performance over a wide temperature range (-30°C to 110°C).
- Long Service Life: The open design allows for efficient lubrication management, while the high-quality chrome steel rings and ceramic balls provide excellent wear resistance.
7028 CD/HCP4A Bearing Typical Application Areas
This bearing is specifically designed for high-performance machinery where speed, precision, and rigidity are paramount. Key applications include:
- Machine Tool Spindles: For high-speed milling, grinding, and turning centers.
- Precision Robotics: In robot arm joints and gears requiring high accuracy and stiffness.
- Aerospace & Defense Systems: In gyroscopes, navigation systems, and other critical rotating assemblies.
- High-Speed Motors and Drives: Especially in electric motors and spindles for semiconductor manufacturing equipment.
