7028 ACD/P4ATGA
7000 Series Super Precision Angular Contact Ball Bearings
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7028 ACD/P4ATGA Bearing Product Overview & Core Advantages
The 7028 ACD/P4ATGA is a precision angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. Engineered to a P4A tolerance class, it offers superior running precision. Its defining feature is the 25° contact angle and Universal Matchable (SU) design, allowing bearings to be mounted in tandem, face-to-face, or back-to-back arrangements to handle combined loads—significant radial and thrust loads in both directions. The phenolic cage and open design contribute to its high-speed capability, making it an ideal solution for high-performance, high-rigidity spindles and machinery.
Model Code Breakdown
| Code Segment | Interpretation | Technical Significance |
|---|---|---|
| 7028 | Basic Bearing Number | Denotes a metric series bearing with a 140 mm bore, 210 mm OD, and 99 mm width. |
| AC | Angular Contact | The bearing is designed to support combined radial and axial loads. |
| D | Two Bearings Matched | Indicates the bearing is supplied as part of a pre-set duplex pair. |
| P4A | Tolerance Class | Signifies a high-precision grade with extremely tight dimensional and running accuracy tolerances. |
| TGA | Cage & Lubrication Code | Specifies a phenolic (Polyamide) cage and is typically associated with a standard grease lubrication suitable for the specified temperature range. |
7028 ACD/P4ATGA Bearing Structural Features & Performance Benefits
High Rigidity and Load Capacity: The angular contact design with a 25° contact angle provides optimized support for heavy combined loads. When used in a Universal Matchable (SU) arrangement, the bearing set creates an extremely rigid system capable of withstanding complex load conditions and moments.
High-Speed Performance: The lightweight and robust phenolic cage is engineered for stability at high rotational speeds, reducing centrifugal forces and friction. This, combined with the open design for efficient lubrication flow, enables a high limiting speed of 6,300 rpm.
Precision Engineering: Manufactured to P4A tolerance class, this bearing ensures minimal runout and vibration, which is critical for applications requiring ultra-high precision and smooth operation.
Optimized Internal Geometry: With 22 precision balls of 22.225 mm diameter, the bearing provides a high dynamic load rating of 70,200 lbf and a static load rating of 106,875 lbf, ensuring long service life under demanding conditions.
7028 ACD/P4ATGA Bearing Typical Application Areas
The 7028 ACD/P4ATGA is ideally suited for high-performance machinery where precision, speed, and rigidity are paramount. Key application areas include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Spindles: Applications in PCB drilling, precision grinding, and other high-accuracy machining processes.
- High-Frequency Motors: Spindles for routers and other high-RPM electric motors.
- Industrial Pumps and Compressors: For applications requiring precise shaft positioning and high rotational accuracy.
