1. Working Condition Defects of Heavy Rotating Equipment

Heavy mining crushers, vertical cement mills, rotary kiln support rollers, large industrial fans and ball mills suffer from three severe operating conditions: elastic deflection of main shaft under heavy load, coaxiality deviation of bearing housing caused by foundation settlement, instantaneous impact load during startup, and composite corrosion from dust and water vapor in open-air workshops.

Conventional cylindrical roller bearings and tapered roller bearings have no self-aligning capability. Slight shaft misalignment will lead to edge overload of rollers, stress concentration and subsequent roller chipping, raceway peeling and cage fracture. Low-cost spherical roller bearings are plagued by unqualified spherical machining, poor fitting between inner and outer spherical surfaces, excessive steel inclusions and unreasonable hardness gradient. Alternating impact load easily triggers internal fatigue crack, rapid clearance expansion, sharp equipment vibration and secondary abrasion of gears, seals and journals.

Enterprises are troubled by inconsistent bearing service life, frequent crusher shutdown for bearing replacement, overheating seizure of kiln roller bearings, fan shutdown due to excessive vibration and high monthly spare parts cost. The root cause is that ordinary bearings cannot realize self-aligning compensation, composite radial & axial load bearing, impact fatigue resistance and dust-waterproof protection simultaneously. Eccentric shaft operation causes continuous overloading and accelerated bearing wear.

2. Product Core Advantages & Positioning

NMT double row spherical roller bearings adopt outer ring spherical raceway + double row symmetrical convex roller structure, customized for shaft deflection, installation misalignment and heavy impact conditions. Integrated with high-precision spherical grinding, gradient heat treatment and high-toughness solid brass cage, the bearing can adaptively compensate angular deviation from shaft bending, housing misalignment and frame deformation, allowing maximum 1.5° shaft deflection. Uniform surface contact of rollers is maintained under eccentric state to eliminate edge stress damage.

The bearing bears ultra-large radial load and bidirectional axial load with outstanding impact absorption capacity, suitable for crusher startup impact, low-speed heavy load of rotary kiln and dynamic unbalanced vibration of fans. Compared with ordinary domestic spherical roller bearings, the fatigue life is increased by over 40%, eccentric resistance is doubled, and wear & corrosion resistance under dusty & humid environment is greatly improved. It effectively protects the main shaft and transmission accessories, extends maintenance cycle and reduces comprehensive cost of spare parts and shutdown overhaul.

3. Structural Design & Series Application Matching

The integrated outer ring spherical raceway, double inner ring raceways, two rows of symmetrical convex rollers and integral cage enable passive self-aligning without manual coaxial calibration. Three core series cover full working conditions from medium heavy load to extreme impact load:

22200 Series (General Medium Heavy Load): Balanced load capacity and self-aligning performance, applied to medium-small ball mills, conveyor drums, induced draft fans, roller presses and bucket elevators, featuring strong versatility and cost performance.

22300 Series (Widened Reinforced Impact-Resistant Type): Widened rollers and increased rolling elements maximize radial load and impact resistance, used for jaw crushers, cone crushers, vertical sand making machines and large vertical mills with drastic startup impact and volatile load.

23000/23100 Series (Thin-Wall Large Bore Low-Speed Heavy Load): Large inner diameter and narrow cross-section design for rotary kiln support rollers, rolling mill back-up rollers and low-speed heavy-load drums with compact installation space, realizing stable large-diameter shaft support and slight eccentricity compensation.

Paired grinding on convex roller surface ensures perfect fit with outer ring spherical surface, avoiding edge crushing failure of straight rollers under eccentric force.

4. Premium Material & Gradient Heat Treatment

NMT adopts vacuum arc remelted carburized bearing steel with strictly controlled internal inclusions and porosity to prevent early fatigue cracks caused by raw material defects. Different from single quenching of ordinary bearings, gradient heat treatment is adopted: deep quenching on raceways and roller contact surface provides excellent wear and pitting resistance; high-toughness matrix of rings and roller core absorbs instantaneous impact stress to avoid brittle cracking caused by excessive hardness.

Integrated solid brass cage undergoes forming and aging hardening treatment with superior toughness, high temperature resistance and anti-tear performance. It is more durable than stamped steel cage under high-frequency vibration and high-temperature lubrication, evenly separating each roller for balanced load distribution. All convex rollers are sorted by micron-level spherical precision to avoid premature failure of unilateral rollers.

5. Spherical Superfinishing & Sealing Upgrade

CNC mirror superfinishing is processed on outer spherical raceway, inner raceways and convex roller surfaces to minimize spherical contour error for smooth deflection without jamming or local extrusion. Low rolling friction ensures excellent temperature rise control under low-speed heavy load and medium-high speed operation to prevent dry seizure from grease deterioration.

The open structure supports customized sealing options: steel dust shield and rubber contact oil seal for mining dust environment; fluorine rubber high-temperature seal for cement and metallurgical humid conditions to block dust, cooling water and ore slurry abrasion. Precise chamfering on bearing rings facilitates hot/cold mounting without scratching journals and housing bores for rapid field overhaul.

6. Wide Industrial Application

Mining Crushing: Jaw crusher, cone crusher, impact crusher, vertical sand maker, ball mill and rod mill main bearing housing;

Cement Building Material: Raw material vertical mill, rotary kiln support roller, kiln head & tail fan, clinker cooler roller table, roller press and cement ball mill;

Metallurgical Sintering: Sintering machine trolley roller, blast furnace induced draft fan, steel slag treatment drum, hot rolling auxiliary roller table and dust removal fan spindle;

Conveying Heavy Machinery: Head & tail drum of long-distance belt conveyor, steep-angle scraper conveyor, bucket elevator and heavy unloader support bearing;

General Industry: Large centrifugal fan, blower, air compressor spindle, paper drying cylinder, marine heavy-duty drive shaft and water conservancy gate drive bearing.

7. Dimension Interchangeability & Technical Service

NMT 222, 223, 230, 231 full series comply with GB and JIS dimensional standards, fully interchangeable with imported bearings of NSK, SKF and FAG for direct replacement without mechanical modification of shafts and housings. Standard C0 clearance and vibration-special C3 clearance are in stock. Custom high-temperature stabilized bearings and pre-filled high-temperature grease are available for rotary kiln high-temperature working conditions.

All finished products pass three strict inspections before delivery: self-aligning angle simulation test, ultimate impact load test and long-term temperature rise durability test with official inspection report. Professional engineers select optimal series, clearance and sealing scheme according to actual eccentricity, impact load, rotating speed, dust level and operating temperature to solve equipment vibration, frequent bearing burnout and roller overheating. It cuts spare parts expenditure, eliminates unplanned production shutdown and improves continuous operation efficiency of production lines for industrial and mining enterprises.