Cylindrical roller bearings adopt a combined structure of parallel cylindrical rollers and straight raceways, featuring ultra-high radial load capacity, strong structural rigidity and excellent limiting rotating speed. They mainly bear pure radial loads, while NJ and NUP models with ribs can withstand unilateral axial positioning force. The bearings are divided into four mainstream structures: NU (inner ring without rib), NJ (inner ring single rib), NUP (inner ring single rib + fixed snap ring) and NF (outer ring single rib). The inner ring and outer ring are separable for easy overall assembly and disassembly maintenance of gearboxes and roller shafts. Cages include solid brass cages, stamped steel cages and nylon cages. Sealing types are open non-sealed type and single/double-sided dust-proof sealed type. As core supporting bearings for industrial gear reducers, hot & cold rolling mill rolls, high-power motor spindles, air compressors, shield machine main drives and wind power gearboxes, they deliver outstanding advantages of high rigidity & deformation resistance, stable high-speed operation, heavy-load fatigue resistance and convenient disassembly & maintenance.

Main model classification: NU (inner ring rib-free), NJ (inner ring single rib), NUP (inner ring single rib + retaining ring), NF (outer ring single rib); Size series: 2000 narrow series, 2200 widened series, 2300 thickened heavy-duty series; Precision grades: P0 general heavy-duty, P6 transmission grade, P5/P4 precision rolling mill grade; Clearance: C0 standard, C3 increased clearance (special for high-speed reducers).

Performance comparison: Compared with spherical roller bearings, it has stronger radial rigidity, lower friction coefficient and much higher allowable rotating speed, without self-aligning function and higher requirements for shaft coaxiality. Compared with tapered roller bearings, it has superior high-speed performance without axial preload adjustment procedures, suitable for continuous high-speed heavy-load gear transmission. Compared with deep groove ball bearings, its rated radial load is increased by 4~8 times with sufficient rigidity to restrain shaft bending deformation, yet it is not applicable for large axial load conditions. Shortcoming: Almost no self-aligning capacity; excessive shaft misalignment will cause eccentric edge wear of rollers. The rib-free NU type cannot bear axial force and needs paired bearings for axial limit.

Metallurgical hot rolling production lines, high-power gear reducers, high-pressure screw air compressors and shield tunneling equipment operate under long-term conditions of continuous high-speed rotation, gear meshing impact, heavy rolling pressure on rollers, oil temperature rise and intrusion of impurities into lubricating oil. Inferior cylindrical roller bearings suffer from poor roller straightness leading to jumping abnormal noise at high speed. Insufficient quenching hardness of ribs causes edge chipping under friction from axial play. Rollers without end chamfer crowning lead to concentrated stress and fragmentation at both ends under heavy load. Poor hardness gradient from heat treatment of inner and outer ring raceways triggers rapid raceway pitting and peeling under alternating high-speed load, directly resulting in abnormal gear meshing clearance of reducers, excessive vibration of mill roll systems, motor rotor stator scraping, abnormal noise and pressure relief of air compressors, seizure shutdown of shield machine main drive bearings, full overhaul of the whole power system and huge production shutdown losses for metallurgical and equipment manufacturing plants.

NMT cylindrical roller bearings cover full structural specifications of NU/NJ/NUP/NF, with sufficient stock for P4/P5 precision rolling mill bearings and C3 increased-clearance high-speed reducer bearings. Manufactured from vacuum degassed refined bearing steel, raceways are processed by super-finish mirror grinding to reduce frictional heat generation at high speed. Cylindrical rollers undergo precision grinding and arc chamfer crowning at both ends to eliminate edge stress concentration and prevent eccentric breakage. Solid brass cages adapt to high-temperature heavy-load conditions of rolling mills and heavy-duty reducers, stamped steel cages serve cost-effective matching for industrial motors, and nylon cages are applied for clean high-speed air compressors. Local high-frequency quenching strengthens ribs of ribbed bearings to resist wear from axial play. The separable inner & outer ring structure fits modular assembly of roller shafts and gearboxes. All dimensions fully comply with national general dimensions for direct replacement of old bearings on reducers, rolling mills and motors without modification of shaft diameters and housing mounting positions.

Heavy-duty gear transmission equipment, metallurgical rolling equipment and high-speed power main engines are upgraded toward high rigidity & deformation resistance, low heat generation at high speed, long fatigue life and modular maintenance. Low-grade cylindrical roller bearings with rough roller precision, insufficient rib hardness and coarse raceway grinding suffer from excessive vibration, cage tearing and raceway peeling after short-term high-speed heavy-load operation, failing to meet the demands of 24-hour continuous rolling in metallurgy and year-round uninterrupted transmission of reducers. The market urgently needs high-rigidity cylindrical roller bearings with high-precision roller forming, reinforced rib heat treatment and super-finished raceway grinding.

NMT achieves ultra-rigid radial support, low temperature rise at high speed and upgraded durability of axial limit via three core processes: precision cylindrical grinding of rollers, local reinforced quenching of ribs and mirror super-finishing of raceways. All finished bearings pass roller roundness & straightness inspection, rib strength impact test and high-speed temperature rise durability test to eliminate defective products with dimensional deviation and heat treatment defects. It ensures continuous stable operation of transmission and rolling equipment and cuts maintenance costs caused by sudden breakdown shutdown.

Core Product Advantages

Parallel cylindrical roller structure delivers extremely strong radial support rigidity to effectively restrain bending deformation of transmission shafts for smoother gear meshing.

Diverse structural options: NU floating type adapts to shafts with thermal expansion & contraction; NJ/NUP realize axial positioning to eliminate extra positioning ring assembly.

Arc chamfer crowning on both roller ends avoids edge stress concentration from misalignment to prevent roller breakage under heavy load.

Mirror super-finished raceways reduce friction resistance at high speed, lower oil temperature rise and extend service life of lubricating oil.

Three cage options: brass cage for high-temperature heavy load, steel cage for cost performance, nylon cage for low noise at high speed.

Separable inner & outer ring structure enables disassembly of gearboxes and rollers without complete machine disassembly for greatly improved maintenance efficiency.

P4/P5 precision bearings are suitable for precision rolling mills and high-speed spindles with small dimensional tolerance and ultra-low rotational runout.

C3 increased-clearance models reserve expansion space for heat generation of high-speed gearboxes to avoid seizure failure from exhausted clearance under high temperature.

Typical Application Scenarios

Internal support bearings for hard-tooth-surface gear reducers, planetary gearboxes and wind power speed-increasing boxes; roll neck support bearings for hot rolling mills and cold rolling mills; main shaft bearings for high-pressure screw air compressors and centrifugal air compressors; front & rear end bearings for large & medium three-phase asynchronous motors and variable frequency motors; main reducer and traveling bearings for shield machines; gearbox bearings for cement vertical mills and bucket-wheel stacker-reclaimers; roller bearings for paper machines and high-speed spinning rollers for chemical fiber spinning.

Quality Assurance

NMT cylindrical roller bearings adopt integral quenching of high-purity bearing steel for uniform raceway hardness and excellent wear resistance, high consistency of roller dimensions and low vibration during high-speed rotation. Compatible with extreme-pressure gear oil and high-speed grease circulating oil supply lubrication, operating temperature ranges from -35℃ to 135℃, adapting to complex working conditions such as high-temperature rolling in metallurgy, oil bath lubrication of gearboxes, continuous high-speed operation of motors and transmission equipment in dusty factory areas.

Product Range

NU rib-free floating type, NJ single-rib positioning type, NUP positioning & limiting type, NF outer ring rib type; Size series: 2000 standard series, 2200 widened series, 2300 thickened heavy-duty series; Precision grades: P0, P6, P5, P4; Clearance: C0 standard, C3 increased clearance; Sealing: open type, double-sided dust cover sealing.

Brand Strength

NMT Japan solves three major pain points of ordinary cylindrical roller bearings: abnormal noise & eccentric fragmentation of rollers at high speed, rib wear & edge chipping, excessive heat generation from rough raceways. Core manufacturing technologies including precision roller machining, rib quenching reinforcement and raceway super-finished grinding deliver high-rigidity cylindrical roller bearings specially for heavy-load high-speed transmission and metallurgical rolling mills. We supply bearings for reducer manufacturers, metallurgical steel rolling enterprises, motor manufacturers, shield equipment manufacturers and wind power supporting enterprises to stabilize working conditions of transmission systems and rolling equipment, and reduce comprehensive costs including shutdown maintenance, gear loss and defective rolled materials caused by bearing failure.