1. Typical Failure Pain Points of Ordinary Bearings for Long Shaft Eccentric Equipment

Long rollers of belt conveyors, industrial centrifugal fans, horizontal water pumps, textile roller shafts and harvester through shafts generally have problems such as slender main shafts prone to bending, misalignment of mounting benchmarks at bearing seats on both ends and long-term force deformation of racks. Conventional deep groove ball bearings and cylindrical roller bearings have no self-aligning ability. Slight inclination of the rotating shaft will cause concentrated force on one side of steel balls, rapid temperature rise of bearings, failure of dry grease, and continuous buzzing abnormal noise.

Unilateral wear of bearings is intensified under eccentric operation. Rapid increase of bearing clearance causes roller shaking leading to belt deviation and tearing, fan impeller rubbing, and water pump seal leakage. Most of these equipment adopt multi-point supported long shaft structure. Replacing bearings requires overall lifting of the long shaft with cumbersome disassembly and assembly procedures. Production line shutdown directly causes interruption of material transportation, shutdown of workshop ventilation and outage of water supply system. Economical ordinary ball bearings have insufficient steel ball precision, resulting in rapid raceway scratch in dusty environment, frequent maintenance and replacement, and continuous increase of equipment operation and maintenance costs.

2. Core Performance Advantages of NMT Double Row Self-Aligning Ball Bearings

Outer Ring Spherical Raceway for Omni-Directional Angular Self-Aligning Compensation

The inner side of the bearing outer ring is an integrated spherical arc raceway. The two rows of internal steel balls can deflect freely in the spherical raceway, allowing maximum axial tilt compensation of 0.5°~1°, perfectly offsetting shaft bending, frame deformation and installation alignment errors, and eliminating overheating wear caused by unilateral load concentration. It is the preferred basic bearing for long-span transmission shafts.

Dual-Row Steel Ball Combined Bearing for Stable Operation and Low Temperature Rise

Two rows of symmetrically arranged precision steel balls share radial load to disperse single-point stress greatly. Compared with single-row bearings, the operating vibration amplitude is reduced by more than 40%. The temperature change is gentle during switching from no-load to full-load of high-speed fans and pumps, and it is not easy to have high-temperature melting loss of grease, suitable for 24-hour continuous operation.

Two Types of Cages for Different Working Conditions

Stamped steel cage: High structural strength and good temperature resistance, suitable for continuous high-temperature operation of fans and water pumps and outdoor dusty working conditions, resistant to dust erosion and deformation;

Nylon injection molded cage: Light weight, low friction coefficient, lower high-speed rotation resistance and outstanding mute effect, mostly used in textile equipment, indoor conveying rollers and precision fans.

Dual Bore Design for Direct Shaft and Adapter Sleeve Installation

Cylindrical inner bore: Interference fit on precision machined main shaft with firm positioning for fixed rotating shaft equipment;

Tapered inner bore: Can be directly installed on ordinary optical shaft with adapter sleeves without precision machining of main shaft. On-site modification and old equipment renovation do not require shaft processing to greatly save renovation working hours.

Precision Machined Steel Balls and Raceways for Dust Resistance and Long Service Life

Rolling elements adopt G5 grade precision steel balls, inner and outer raceways are superfinely ground with high surface finish to avoid dust adhesion and accumulation. Two sealing structures of double-sided rubber seal and iron seal are optional to effectively block dust and water vapor from entering the raceway, adapting to harsh environments of open-air conveyors and field agricultural machinery.

Standardized Universal Dimensions for Direct Replacement of Imported Parts

Strictly follow the national standard 12000 and 22000 series overall dimensions. The outer diameter, inner diameter and thickness are fully universal. No modification of bearing housing is required for new and old equipment replacement, featuring strong versatility of spare parts and convenient inventory preparation.

3. Core Application Scenarios

1. Belt Conveying Equipment

Support bearings for head and tail rollers and intermediate idlers of coal mine, sand and grain belt conveyors compensate for bending deformation of long roller shafts, prevent belt deviation and edge wear of conveyor belts, and ensure continuous material transportation.

2. Industrial Ventilation Fans

Main shaft bearings for boiler induced draft fans, centrifugal ventilation fans and cooling tower fans solve axial offset caused by fan base deformation, reduce fan operating noise and avoid friction collision between impeller and casing.

3. Water Supply and Drainage Pump Equipment

Support bearings for horizontal clean water pumps, circulating water pumps and cooling tower pumps balance radial runout of pump shaft impellers, protect mechanical seals of water pumps and reduce water leakage failures.

4. Textile Printing and Dyeing Machinery

Long transmission shaft bearings for carding machines, spinning machines and printing and dyeing rollers maintain high-speed stable rotation of rollers, ensure flatness of yarn and fabric forming and reduce textile defects.

5. Agricultural Field Operation Machinery

Long transmission shaft bearings for wheat harvesters, corn harvesters and straw crushers adapt to bumpy vibration, mud and dust environment in farmland and resist deformation and misalignment during agricultural machinery operation.

6. Light Industrial Transmission Devices

Long shaft conveying rollers, small mixing shafts, woodworking machinery transmission shafts and cooling tower transmission shafts solve long shaft alignment problems at low cost, suitable for medium-low speed light and medium load transmission.

4. Practical Working Condition Selection Guide

Inner Bore Structure Selection

Fixed installation of precision finished main shaft → cylindrical bore self-aligning ball bearing;

Optical shaft installation and old equipment renovation → tapered bore self-aligning ball bearing + matching adapter sleeve.

Cage Selection

Outdoor, high temperature, heavy dust and 24-hour continuous operation → stamped steel cage;

Indoor high speed, mute requirement and clean working conditions → nylon cage.

Sealing and Clearance Selection

Indoor clean environment: Open type without seal for convenient grease refilling;

Open-air, dust and water vapor environment: Double-sided rubber seal 2RS;

Standard clearance for normal temperature working conditions, C3 increased clearance for high-temperature fans to offset thermal expansion.

Load Definition

Self-aligning ball bearings are preferred for pure radial load without obvious axial force; combined use with thrust bearings if large axial force exists.

5. Long-Term Comprehensive Cost Comparison

Ordinary deep groove ball bearings will fail due to overheating abnormal noise, excessive clearance and raceway scratch within 4–7 months under long shaft eccentric working conditions. The disassembly and maintenance period of long shaft equipment is long, and the loss of production line shutdown far exceeds the bearing procurement cost.

Benefiting from spherical self-aligning structure and precision steel ball processing technology, NMT double row self-aligning ball bearings achieve a service life of 12–20 months under conventional working conditions such as conveyors, fans and water pumps, greatly reducing three major expenditures: bearing spare parts procurement, shutdown maintenance and loss of belt/seal wear. After the stability of rotating shaft operation is improved, the replacement cycle of vulnerable parts such as belts, impellers, mechanical seals and shaft sleeves is extended synchronously, and the annual operation and maintenance cost of the whole equipment is reduced by more than 50%, serving as a cost-effective standard bearing for equipment with long shaft alignment deviation.