7028 CD/P4ADBA
7000 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
7028 CD/P4ADBA
Basic Information
System of measurement
Metric
Weight
6.84 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
66 mm
Width tolerance
-0.2mm to 0
Contact angle
15 °
Ball & Washer Dimensions
Ball diameter
22.225 mm
Ball quantity
22
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
55575 lbf
Radial static load rating
75375 lbf
Limiting speed
6.3 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Duplex Back-to-Back (DB)
Number of bearings in matched set
2
Universal matching bearing
No (Standard)
Preload
Extra light / Class A
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
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7028 CD/P4ADBA Bearing Product Overview & Core Advantages
The 7028 CD/P4ADBA is a precision duplex angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. This matched back-to-back (DB) arrangement is preloaded to Extra Light (Class A) specifications, providing superior axial and radial stiffness while minimizing friction and heat generation. Its P4A tolerance class ensures extremely tight dimensional and running accuracy, making it ideal for high-speed spindles and other precision machinery where high rigidity and minimal runout are critical. The open design allows for customized lubrication schemes to optimize performance.
Model Code Breakdown
| Code Segment | Technical Meaning |
|---|---|
| 7028 | Basic bearing designation indicating a 140mm bore, 210mm OD, and 66mm width. |
| CD | Specifies a duplex bearing in a Back-to-Back (DB) arrangement. This configuration provides high moment rigidity and excellent stability under complex loads. |
| P4A | Indicates a super-precision tolerance class. P4A specifies even tighter running accuracy and dimensional tolerances than standard P4, suitable for the most demanding high-speed applications. |
| DBA | Denotes the specific preload level. In this case, Extra Light preload (Class A), which is optimal for very high speeds and low heat generation. |
7028 CD/P4ADBA Bearing Structural Features & Performance Benefits
- High Rigidity & Stability: The back-to-back duplex design creates a wide, stable support system that effectively resists moment loads and tilting, ensuring precise shaft positioning and high rigidity.
- Superior Load Capacity: With a 15° contact angle and a dynamic load rating of 55,575 lbf, this bearing is engineered to handle significant combined loads (radial and axial) simultaneously.
- Optimized for High-Speed Operation: The phenolic resin cage is lightweight and robust, contributing to lower centrifugal forces and smooth operation at the limiting speed of 6,300 rpm. The open seal type facilitates efficient lubrication management for high-speed performance.
- Precision Engineering: Manufactured to P4A super-precision standards with extremely tight tolerances on all bearing dimensions (bore, OD, width), this unit guarantees minimal vibration and exceptional running accuracy.
- Durable Construction: Components made from chrome steel for both rings and balls ensure high fatigue life and durability under demanding operating conditions.
7028 CD/P4ADBA Bearing Typical Application Areas
This bearing is specifically designed for high-performance applications, including:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers requiring extreme precision and rigidity.
- Precision Grinding Spindles: Applications where minimal runout and thermal stability are paramount.
- High-Frequency Motors: Spindles for PCB drilling and other high-RPM electric motors.
- Medical Equipment: High-speed rotors in dental handpieces and medical imaging devices.
- Aerospace & Defense Systems: Gyroscopes, radar systems, and other instrumentation requiring superior accuracy.
