QJ 308 MA
Four-Point Contact Bearings Ball Bearings
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Part No.
Part No.
QJ 308 MA
Basic Information
Bearing type
Ball
System of measurement
Metric
Construction
Single Row
Weight
0.78 kg
Tolerance class
P6 (ABEC-3)
Seal type
Open
For load direction
Four Point Contact
Main Dimensions
Bore diameter
40 mm
Bore diameter tolerance
-0.01mm to 0
Outside diameter
90 mm
Outside diameter tolerance
-0.013mm to 0
Width
23 mm
Width tolerance
-0.05mm to 0
Chamfer dimension
1.5 mm
Distance from side face to load point
46 mm
Inner Ring Dimensions
Inner ring large-side shoulder diameter
52 mm
Outer Ring Dimensions
Shoulder diameter outer ring
72.5 mm
Performance
Temperature range
-30° to 110 °C
Radial dynamic load rating
17550 lbf
Radial static load rating
14400 lbf
Limiting speed
14 X 1000 rpm
Lubrication
Lubricated
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Brass
Environment & Compliance
REACH
Compliant
ROHS
Compliant
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
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QJ 308 MA Bearing Product Overview & Core Advantages
The QJ 308 MA is a four-point contact ball bearing designed for exceptional performance in demanding applications. This metric single-row bearing excels at simultaneously handling combined radial loads and substantial axial loads from both directions. Manufactured to a P6 (ABEC-3) tolerance class, it delivers high running accuracy and reliability. Its compact design, featuring a 40 mm bore and 90 mm outside diameter, makes it an ideal solution for space-constrained, high-precision assemblies requiring robust load support.
QJ 308 MA Bearing Model Code Explained, Specifications & Naming Convention
| Suffix | Technical Meaning |
|---|---|
| MA | Indicates the bearing is pre-lubricated with a specific grease, offering immediate readiness for installation and operation. |
| Open | Signifies an unsealed design, allowing for optimal heat dissipation and the potential for custom lubrication regimes in controlled environments. |
QJ 308 MA Bearing Structural Features & Performance Benefits
- Four-Point Contact Design: The optimized raceway geometry enables a single bearing row to support significant axial loads in both directions as well as radial loads, simplifying assembly design and reducing component count.
- High Precision & Rigidity: Built to P6 tolerance with a brass cage, this bearing ensures smooth operation, minimal vibration, and precise shaft positioning, which is critical for applications like machine tool spindles.
- Robust Load Capacity: With a dynamic load rating of 17,550 lbf and a static load rating of 14,400 lbf, it is engineered for long service life under heavy combined loads.
- Optimized for High-Speed Operation: The combination of the precision-ground chrome steel components and the brass cage contributes to a high limiting speed of 14,000 rpm.
- Pre-Lubricated for Immediate Use: The "MA" suffix indicates factory-applied lubrication, ensuring immediate startup and protection during the initial run-in period.
QJ 308 MA Bearing Typical Application Areas
This bearing is ideally suited for high-performance machinery and systems, including:
- Machine Tool Spindles
- Industrial Gearboxes
- Pumps and Compressors
- Precision Robotics and Automation Equipment
- Aerospace Actuation Systems
