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The 344 Series Cylindrical Roller Bearings are critical components for large-scale industrial drive systems. Utilizing precision-machined cylindrical rollers in line contact with the raceways, these bearings offer massive radial load capacity and high structural rigidity. Their separable inner or outer ring design greatly simplifies the mounting and maintenance process on heavy equipment, especially when tight interference fits are mandatory on large shafts.
Please verify these heavy-duty bearing dimensions against your equipment maintenance manual or BOM.
Item | Specification |
Designations | NU344, NJ344 |
Bearing Type | Large-size single-row cylindrical roller bearing |
Bore diameter (d) | 220.00 mm |
Outer diameter (D) | 460.00 mm |
Width (B) | 88.00 mm |
Weight | ≈ 73.4 kg |
Cage options | Machined brass (M/MA) or Stamped steel (J) |
Precision Class | P0 (Standard); higher precision available |
Selecting the correct flange configuration is essential for proper shaft guidance in heavy machinery:
NU344: Features two integral flanges on the outer ring and a smooth, flangeless inner ring. This allows the shaft to expand and contract axially in both directions without creating internal stress, acting as a perfect non-locating bearing.
NJ344: Features two flanges on the outer ring and one flange on the inner ring. This semi-locating design can support heavy radial loads while also accommodating axial forces in one direction, preventing the shaft from drifting.
Due to their massive 460 mm outer diameter and approx. 73 kg weight, the NU344 and NJ344 are deployed in heavy industries where equipment failure is not an option. Primary applications include:
Rolling mills and steel processing equipment.
Large industrial gearboxes and wind turbine transmissions.
Heavy-duty oilfield equipment and mud pumps.
High-power electric motors and traction generators.
We specialize in supplying large-scale industrial bearings to global distributors and machinery OEMs. We offer heavy-duty machined brass cages (M suffix) specifically optimized for the high vibrations found in mining and steel applications. We provide comprehensive OEM services, including laser marking of your brand and custom internal clearances (such as C3 or C4) for high-heat environments. All large bearings are packed in secure, anti-corrosion export wooden boxes.
Q1: What does the "M" or "MA" suffix mean (e.g., NU344M)?
A: The "M" or "MA" suffix indicates the bearing is equipped with a machined brass cage. This cage type is highly recommended for large bearings as it offers superior strength, better lubrication retention, and excellent resistance to shock loads compared to standard steel cages.
Q2: Can the NU344 handle thrust (axial) loads?
A: No. The NU344 is designed purely for radial loads and allows free axial movement. If you need to support axial loads in one direction, you should specify the NJ344.
Q3: How are bearings of this size shipped?
A: Due to the high weight (over 70 kg per piece), these bearings are heavily greased with anti-rust oil, wrapped in waterproof material, and securely packed in reinforced wooden crates or pallets suitable for international sea or air freight.
Q4: Do you offer inspection reports before shipment?
A: Yes. For heavy-duty large bearings, we can provide detailed factory inspection reports covering dimensional accuracy, radial runout, and material certification to support your incoming quality control processes.
The 344 Series Cylindrical Roller Bearings are critical components for large-scale industrial drive systems. Utilizing precision-machined cylindrical rollers in line contact with the raceways, these bearings offer massive radial load capacity and high structural rigidity. Their separable inner or outer ring design greatly simplifies the mounting and maintenance process on heavy equipment, especially when tight interference fits are mandatory on large shafts.
Please verify these heavy-duty bearing dimensions against your equipment maintenance manual or BOM.
Item | Specification |
Designations | NU344, NJ344 |
Bearing Type | Large-size single-row cylindrical roller bearing |
Bore diameter (d) | 220.00 mm |
Outer diameter (D) | 460.00 mm |
Width (B) | 88.00 mm |
Weight | ≈ 73.4 kg |
Cage options | Machined brass (M/MA) or Stamped steel (J) |
Precision Class | P0 (Standard); higher precision available |
Selecting the correct flange configuration is essential for proper shaft guidance in heavy machinery:
NU344: Features two integral flanges on the outer ring and a smooth, flangeless inner ring. This allows the shaft to expand and contract axially in both directions without creating internal stress, acting as a perfect non-locating bearing.
NJ344: Features two flanges on the outer ring and one flange on the inner ring. This semi-locating design can support heavy radial loads while also accommodating axial forces in one direction, preventing the shaft from drifting.
Due to their massive 460 mm outer diameter and approx. 73 kg weight, the NU344 and NJ344 are deployed in heavy industries where equipment failure is not an option. Primary applications include:
Rolling mills and steel processing equipment.
Large industrial gearboxes and wind turbine transmissions.
Heavy-duty oilfield equipment and mud pumps.
High-power electric motors and traction generators.
We specialize in supplying large-scale industrial bearings to global distributors and machinery OEMs. We offer heavy-duty machined brass cages (M suffix) specifically optimized for the high vibrations found in mining and steel applications. We provide comprehensive OEM services, including laser marking of your brand and custom internal clearances (such as C3 or C4) for high-heat environments. All large bearings are packed in secure, anti-corrosion export wooden boxes.
Q1: What does the "M" or "MA" suffix mean (e.g., NU344M)?
A: The "M" or "MA" suffix indicates the bearing is equipped with a machined brass cage. This cage type is highly recommended for large bearings as it offers superior strength, better lubrication retention, and excellent resistance to shock loads compared to standard steel cages.
Q2: Can the NU344 handle thrust (axial) loads?
A: No. The NU344 is designed purely for radial loads and allows free axial movement. If you need to support axial loads in one direction, you should specify the NJ344.
Q3: How are bearings of this size shipped?
A: Due to the high weight (over 70 kg per piece), these bearings are heavily greased with anti-rust oil, wrapped in waterproof material, and securely packed in reinforced wooden crates or pallets suitable for international sea or air freight.
Q4: Do you offer inspection reports before shipment?
A: Yes. For heavy-duty large bearings, we can provide detailed factory inspection reports covering dimensional accuracy, radial runout, and material certification to support your incoming quality control processes.
