FAG QJ338‑N2‑MPA 190x400x78 Four-Point Contact Ball Bearing

Applications in Industrial Systems

The FAG QJ338-N2-MPA bearing is engineered for demanding industrial applications where both axial and radial loads must be transmitted reliably in a compact width. With dimensions of 190 mm bore, 400 mm outside diameter and 78 mm width, it fits into large-shaft drive systems, gearbox assemblies, machine tool spindles, heavy duty units and bearing housings within production lines. Among its primary uses are transmissions, heavy machinery, lifting equipment and other industrial drive systems where durability and precision are essential.

Key Advantages & Technical Features

• Four-point contact design allows this bearing to accommodate combined loads — axial in both directions as well as radial loads — enabling compact bearing arrangements and stable shaft guidance.

• Designation “N2-MPA”: “N2” indicates two locating grooves on the outer ring (for secure mounting in a bearing housing) and “MPA” refers to a brass cage guided on the outer ring, enhancing stability, heat dissipation and service life.

• Dimensions 190x400x78 mm reflect the standard sizing for this model, ensuring interchangeability and suitability for large-shaft equipment.

• Heavy-duty load capacity: Manufacturers list a radial dynamic load rating of approximately 740 kN and a static radial load rating of about 1 250 kN for this type.

• Industrial grade construction supports applications in harsh environments, reduction of downtime, high durability and longevity under demanding conditions.

Technical Specifications Summary

• Manufacturer: FAG

• Model: QJ338-N2-MPA

• Bearing type: four-point contact ball bearing (a variant of angular contact design)

• Bore Ø: 190 mm

• Outer Ø: 400 mm

• Width: 78 mm

• Cage: brass, guided on outer ring

• Retaining features: two outer-ring grooves (N2) for housing securement

• Suitable for industrial applications: high-load gearboxes, large rotating shafts, bearing housings, unit assemblies

• Availability: from our warehouse in Lublin (ul. Smoluchowskiego 1, building 4) with 24h dispatch

This bearing serves as a robust unit for heavy-duty applications where a standard radial bearing would be insufficient or where space constraints demand a combined load solution. Use cases include machine tools, gearboxes, rolling mills, manufacturing equipment, large motors and other drive systems requiring a premium bearing solution.

FAQ

Q 1: What distinguishes a four-point contact bearing from a standard angular contact ball bearing?
A: A four-point contact bearing is designed with one raceway groove per ring but arranged so that the balls contact each ring at four points under load. This enables a single bearing to sustain axial loads in both directions plus radial loads, reducing the number of bearings required. A standard angular contact bearing typically supports axial load in one direction only or needs paired arrangement.

Q 2: What does the “N2-MPA” suffix mean in this model?
A: “N2” denotes two locating grooves on the outer ring, enabling secure positioning in the housing and preventing ring rotation in service. “MPA” identifies a brass (metal) cage guided by the outer ring, offering enhanced structural stability, improved heat dissipation and longer service life.

Q 3: How do I choose the right bearing size for the system?
A: Selection depends on matching bore (shaft) diameter, outer ring diameter (housing bore) and width (axial space available), as well as considering load types (radial vs axial), speed, temperature and service conditions. In this case, the bore must be ≈190 mm, the housing bore ≈400 mm and the available width 78 mm.

Q 4: Is this bearing suitable for industrial automation and heavy-duty gearboxes?
A: Yes. The FAG QJ338-N2-MPA is explicitly designed for heavy industrial applications, large shafts and gearbox housings requiring combined load capacity (radial + axial), high durability, and reliable operation under demanding conditions.

Q 5: Why purchase through a B2B specialist rather than a general parts supplier?
A: A B2B supplier focuses on industrial-grade components, offers support for correct selection of bearing units, bulk order options, warehoused stock, streamlined logistics and faster dispatch. This minimizes downtime, ensures correct mounting and provides longer service life for critical equipment.