7028 ACDGA/HCP4A
Hybrid Ceramic Super Precision Bearings
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Part No.
Part No.
7028 ACDGA/HCP4A
Basic Information
System of measurement
Metric
Weight
2.83 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
140 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
210 mm
Outside diameter tolerance
-0.004mm to 0
Width
33 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
22.225 mm
Ball quantity
22
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
32850 lbf
Radial static load rating
35100 lbf
Limiting speed
6.3 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Single
Number of bearings in matched set
3
Universal matching bearing
Universal Matchable (SU)
Preload
Extra light / Class A
Materials
Ring material
Chrome Steel
Ball material
Ceramic
Cage material
Phenolic
Technical Drawings
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In Stock
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Product Overview and Core Advantages
The 7028 ACDGA/HCP4A is a high-precision angular contact ball bearing designed for demanding applications requiring exceptional accuracy and performance. This single bearing features a 25° contact angle and Extra Light (Class A) preload, making it ideal for applications requiring high rigidity and minimal deflection under combined loads. Its P4A tolerance class ensures superior running accuracy, while the ceramic balls and phenolic cage contribute to high-speed capability and reduced weight. This bearing is universally matchable (SU), allowing for precise arrangement in sets of three to optimize system performance.
7028 ACDGA/HCP4A Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 7028 | Basic bearing series, indicating a bore diameter of 140 mm, outside diameter of 210 mm, and width of 33 mm. |
| AC | Angular Contact design, optimized for combined radial and axial loads. |
| DGA | Designates a specific internal geometry and contact angle of 25°. |
| HCP4A | Indicates the P4A tolerance class for ultra-high precision and the bearing is supplied lubricated from the factory. |
Structural Features and Performance Benefits
- High Rigidity and Precision: The angular contact design with a 25° contact angle and Class A preload provides superior stiffness and minimizes axial and radial play, ensuring precise shaft positioning and reduced vibration.
- Enhanced Speed and Temperature Performance: The combination of ceramic balls (silicon nitride) and a phenolic resin cage reduces centrifugal forces, lowers operating temperature, and enables a high limiting speed of 6,300 rpm. This construction is suitable for a temperature range of -30°C to 110°C.
- Superior Load Capacity: Engineered to handle significant combined loads, with a dynamic load rating of 32,850 lbf and a static load rating of 35,100 lbf.
- Optimized for Matched Sets: As a Universal Matchable (SU) bearing, it can be supplied in pre-matched sets (typically 3 bearings) to create a pre-loaded arrangement that delivers maximum system rigidity and accuracy without additional adjustment.
7028 ACDGA/HCP4A Bearing Typical Application Areas
This precision bearing is ideally suited for high-performance machinery where accuracy, speed, and rigidity are paramount. Key applications include:
- Machine Tool Spindles: For high-speed milling, grinding, and turning centers.
- Precision Grinding Spindles: Providing the necessary rigidity and run-out accuracy.
- High-Frequency Motors and Spindles: Where ceramic components enable higher rotational speeds.
- Industrial Pumps and Compressors: For applications requiring reliable operation under combined loads.
- Aerospace and Defense Systems: In gyroscopes, radar systems, and other precision instruments.
