QJ 311 N2MA
Four-Point Contact Bearings Ball Bearings
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Part No.
Part No.
QJ 311 N2MA
Basic Information
Bearing type
Ball
System of measurement
Metric
Construction
Single Row
Weight
1.75 kg
Tolerance class
P6 (ABEC-3)
Seal type
Open
For load direction
Four Point Contact
Main Dimensions
Bore diameter
55 mm
Bore diameter tolerance
-0.012mm to 0
Outside diameter
120 mm
Outside diameter tolerance
-0.013mm to 0
Width
29 mm
Width tolerance
-0.05mm to 0
Chamfer dimension
2 mm
Distance from side face to load point
61 mm
Inner Ring Dimensions
Inner ring large-side shoulder diameter
70.5 mm
Outer Ring Dimensions
Shoulder diameter outer ring
97.8 mm
Performance
Temperature range
-30° to 110 °C
Radial dynamic load rating
30825 lbf
Radial static load rating
26550 lbf
Limiting speed
10 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
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In Stock
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QJ 311 N2MA Bearing Product Overview & Core Advantages
The QJ 311 N2MA is a metric four-point contact ball bearing engineered for exceptional performance in demanding applications. This single-row bearing is distinguished by its ability to simultaneously support high combined loads, including significant radial loads and axial loads in both directions. Manufactured to a P6 (ABEC-3) tolerance class, it delivers the high precision and high rigidity required for accurate rotational motion. Its compact design, with a 55 mm bore and 120 mm outside diameter, makes it an ideal solution for space-constrained, high-reliability machinery.
Model Code Breakdown
| Code Segment | Technical Meaning |
|---|---|
| QJ 311 | Standard designation for a four-point contact ball bearing with a 55mm bore and 120mm outside diameter. |
| N2 | Indicates the bearing has two machined grooves in the outer ring for securing snap rings. |
| MA | Signifies that the bearing is pre-lubricated with a specific, high-performance grease. |
QJ 311 N2MA Bearing Structural Features & Performance Benefits
- Four-Point Contact Design: The raceway geometry allows the bearing to handle combined radial and axial loads from both directions with a single bearing row, offering a compact and simplified design compared to traditional duplex pairs.
- High Rigidity and Precision: Built to a P6 tolerance class with a brass cage for dimensional stability and smooth operation under high loads, ensuring precise shaft guidance and minimal runout.
- Robust Load Capacity: With a dynamic load rating of 30,825 lbf and a static load rating of 26,550 lbf, this bearing is designed for long service life in heavy-duty applications.
- Integrated Retention: The N2 suffix denotes grooves for snap rings, facilitating secure axial location within the housing without additional complex components.
- Ready-to-Install: The MA lubrication ensures the bearing is pre-filled with grease, providing immediate operation and reducing initial setup time.
QJ 311 N2MA Bearing Typical Application Areas
This bearing's unique combination of high load capacity and compact design makes it suitable for a wide range of industrial sectors, including:
- Robotics and Automation: Used in robotic arm joints and rotary actuators.
- Machine Tools: Ideal for rotary tables, indexing heads, and swivel bases.
- Material Handling: Found in turntables and slewing rings for cranes and excavators.
- Aerospace and Defense: Applied in radar bases, missile launchers, and other precision positioning systems.
