Large Radial Clearance Double-row Self-aligning Ball Bearing

I. Product Overview​

Double-Row Self-Aligning Ball Bearings with Large Radial Clearance (abbreviated as DRSABB-LC) are a core category within the double-row self-aligning ball bearing family, specifically designed for complex working conditions characterized by heavy loads, significant high-temperature thermal expansion, and large shaft system deviations. Their core competitiveness lies in the triple adaptability of "high radial load-carrying capacity + wide-clearance thermal compensation + self-alignment" - they not only inherit the heavy-load advantage of the double-row structure (radial rated dynamic load is 60%-100% higher than that of single-row models of the same size) but also absorb thermal elongation of the shaft system caused by high temperatures through large radial clearances of Grade C3/C4/C5 (50%-150% larger than standard clearance Grade CN). Meanwhile, relying on the spherical raceway of the outer ring, they can compensate for angular deviations of 1°-3.5° (up to 3.5° for large-sized models), completely solving the industry pain points of "bearing seizure and local overload failure" for heavy-load equipment in high-temperature scenarios with limited installation accuracy.​

The outer diameter of this type of bearing ranges from 20mm to 500mm, with an inner diameter spanning 10mm to 250mm and a basic dynamic load rating of 8kN-350kN. Primarily designed to bear heavy radial loads, it can simultaneously carry bidirectional axial loads equivalent to 20%-35% of the radial rated load (e.g., slight axial movement during equipment operation), eliminating the need for additional thrust bearings and simplifying the transmission structure. The limiting speed under grease lubrication is 6,000-15,000 r/min (slightly lower than that of standard double-row models due to expanded clearance), making it suitable for key transmission systems in heavy-load and high-temperature fields such as metallurgical rolling mills, mining ball mills, and chemical drying equipment.​

Compared with double-row self-aligning ball bearings with standard clearance, targeted optimizations have been made to their material toughness and heat dissipation structure, enabling stable operation within a temperature fluctuation range of -30℃ to +180℃. The equipment downtime failure rate is reduced by more than 65% compared to standard models, making them particularly suitable for heavy-load equipment that operates long-term in high-temperature, high-vibration environments with limited installation accuracy.​

II. Core Structure and Design Features​

1. Precision Structural Composition​

The four core components of DRSABB-LC are optimized to meet the triple requirements of "heavy-load bearing, wide-clearance adaptation, and vibration resistance with heat dissipation", ensuring reliable operation under complex working conditions:​

Inner Ring: Adopts a double-row symmetrical spherical raceway structure, with a raceway radius of curvature slightly larger than that of standard clearance models (curvature coefficient f=0.52-0.55, compared to f=0.51-0.53 for standard models), reserving sufficient space for expanded radial clearance. The inner bore of the inner ring is divided into two types: cylindrical bore (no suffix) and tapered bore (suffix K/K30, with a taper of 1:12 or 1:30). Models with tapered bores need to be installed with adapter sleeves (H) or withdrawal sleeves (AH) to facilitate adjustment of bearing clearance. The material used is modified high-toughness SUJ2 bearing steel, which undergoes "low-temperature carburizing + vacuum quenching + ultra-precision grinding" processes. The surface hardness reaches HRC 62-65, while the core hardness is maintained at HRC 28-32, ensuring excellent deformation resistance under the wide-clearance structure (deformation ≤ 0.01mm under rated radial load). For models used in high-temperature scenarios (e.g., adapted for metallurgical rolling mills), 20CrNiMo alloy carburized steel is adopted, improving high-temperature oxidation resistance by 40%.​

Outer Ring: The inner surface of the outer ring is a shared spherical raceway, with the center of the spherical curvature coinciding with the bearing axis - this is the core structure enabling the self-aligning function. The wall thickness of the outer ring is 25%-30% thicker than that of standard clearance models (e.g., for a model with an inner diameter of 50mm, the outer ring wall thickness increases from 8mm to 10.5mm), enhancing resistance to vibration and impact and preventing outer ring cracking under wide clearance. Some models for high-temperature and high-vibration conditions are processed with annular heat dissipation grooves (depth 2mm-3mm, width 3mm-4mm), which can reduce operational temperature rise by 10-15℃. Models with lubrication grooves (suffix /W33) are equipped with 3-5 evenly distributed oil holes (diameter 4mm-8mm) on the outer ring, facilitating the replenishment of high-temperature grease (e.g., lithium-based high-temperature grease, temperature resistance ≤ 200℃) via high-pressure lubrication systems and extending maintenance intervals.​

Rolling Elements (Double-Row Steel Balls): High-purity GCr15SiMn bearing steel balls are used, arranged in a double-row symmetrical configuration. The diameter of the steel balls is 10%-20% larger than that of standard clearance models of the same size, and the quantity is 1.8-2 times that of single-row models. Through coordinated load-bearing of the double rows, radial heavy loads are distributed to reduce the force on individual steel balls. Processed via "vacuum melting + precision grinding + nano-level polishing", the roundness error is ≤ 0.15μm, and the surface roughness is Ra ≤ 0.08μm, ensuring uniform contact with the spherical raceways and reducing local wear under wide clearance. For high-corrosion scenarios (e.g., chemical equipment), silicon nitride ceramic balls are optional, which improve acid and alkali corrosion resistance by 90% and are suitable for harsh environments.​

Cage: Classified into two types based on speed and load requirements:​

For medium-low speed heavy-load scenarios (rotational speed ≤ 10,000 r/min), HPb59-1 solid brass cages are used, offering excellent wear resistance and heat dissipation, and capable of withstanding instantaneous impact loads;​

For medium-high speed scenarios (rotational speed ≤ 15,000 r/min), PA66 + 30% glass fiber reinforced nylon cages are adopted, which are 40% lighter than brass cages and have a friction coefficient as low as 0.002-0.003.​

The cage pockets adopt a "double-row symmetrical design", with the clearance between the cage and steel balls controlled at 0.15mm-0.25mm to avoid noise caused by steel ball movement during high-speed operation (no-load noise ≤ 52dB).​

2. Key Design Characteristics​

Wide Clearance for Thermal Expansion Adaptation: Three levels of radial clearance (C3/C4/C5) are available based on working condition requirements:​

Grade C3 (clearance 50%-80% larger than Grade CN) is suitable for scenarios with slight thermal expansion (e.g., ordinary heavy-load fans, water pumps, temperature fluctuation ≤ 50℃);​

Grade C4 (clearance 80%-120% larger than Grade CN) is for scenarios with moderate thermal expansion and vibration (e.g., auxiliary rolls of metallurgical rolling mills, mining vibrating screens, temperature fluctuation ≤ 80℃);​

Grade C5 (clearance 120%-150% larger than Grade CN) is designed for extreme thermal expansion and installation deviation scenarios (e.g., chemical drying equipment, high-temperature conveyor belts, temperature fluctuation ≤ 120℃). This design fully absorbs thermal elongation of the shaft system, preventing bearing seizure.​

High Radial Load-Carrying Capacity and Impact Resistance: With coordinated load-bearing of double-row steel balls, the radial rated dynamic load is 60%-100% higher than that of single-row models of the same size (e.g., Model 2220C4 (100mm inner diameter, 180mm outer diameter) has a basic dynamic load rating of 195kN, while the same-sized single-row Model 1220C4 only has 105kN). It can withstand instantaneous impact loads up to 5-7 times the rated load, making it suitable for heavy-load equipment such as mining crushers and metallurgical rolling mills.​

Strong Self-Aligning and Deviation Resistance: The spherical raceway design of the outer ring allows angular deviations of 1°-3.5° in the shaft system, compensating for alignment issues caused by misaligned bearing housing installation (coaxiality error ≤ 0.3mm) and shaft bending after long-term operation (deflection ≤ 0.2mm/m). Combined with wide radial clearance, it provides dual adaptation to shaft system deviations, reducing local load overload on the raceways.​

Vibration Resistance and Heat Dissipation Optimization: The thickened outer ring and high-toughness material enhance vibration and impact resistance, enabling the bearing to withstand instantaneous vibration acceleration ≤ 12m/s² (e.g., in mining vibrating screens). The heat dissipation grooves on the outer ring of some models accelerate heat conduction, ensuring that the operational temperature rise is ≤ 45℃ (at an ambient temperature of 25℃) under high-temperature conditions (e.g., 150℃), preventing bearing damage due to lubricant failure.​

III. Main Product Models and Classification​

1. Classification by Size and Clearance Grade​

Based on inner diameter and clearance grade, DRSABB-LC can be categorized as follows to accurately match different heavy-load and high-temperature scenarios:

2. Classification by Installation and Seal Method​

Double-Row Self-Aligning Bearings with Large Clearance and Cylindrical Bore (No Suffix): The inner ring has a standard cylindrical bore, directly connected to the shaft via an interference fit. Suitable for scenarios with high shaft diameter accuracy (e.g., precision heavy-duty motors).​

Double-Row Self-Aligning Bearings with Large Clearance and Tapered Bore (Suffix K/K30): The inner ring has a 1:12 (K) or 1:30 (K30) tapered bore, requiring installation with adapter sleeves (H) or withdrawal sleeves (AH) to facilitate adjustment of bearing clearance. Suitable for scenarios with large shaft diameters and limited installation space (e.g., drive shafts of mining crushers).​

Sealed Double-Row Self-Aligning Bearings with Large Clearance (Suffix 2Z/2RS): Suffix 2Z (double-sided steel dust covers) is suitable for dry high-temperature environments (e.g., drying equipment, heating furnaces); suffix 2RS (double-sided nitrile rubber seals) achieves an IP54 dust and water resistance rating, making it suitable for humid, low-dust high-temperature scenarios (e.g., chemical pumps, hot rolls of printing and dyeing machines).​

Double-Row Self-Aligning Bearings with Large Clearance and Lubrication Grooves (Suffix /W33): Equipped with an annular lubrication groove and multiple oil holes on the outer ring, suitable for long-term continuous operation scenarios requiring regular grease replenishment (e.g., rolls of metallurgical rolling mills, mining ball mills).​

IV. Applicable Industries and Typical Applications​

With core advantages of "high radial load-carrying capacity + wide-clearance thermal compensation + self-alignment", DRSABB-LC are widely used in industrial fields with heavy loads, high temperatures, and large shaft system deviations. Typical applications include:​

Metallurgical Industry: Backup rolls of metallurgical rolling mills (suitable for Model 22328C4, withstanding moderate thermal expansion and heavy loads), conveyor belts of billet heating furnaces (suitable for Model 2224C5/W33, resisting extreme thermal expansion and dust), and rolls in the cooling section of continuous casting machines (suitable for Model 2220C3, compensating for installation deviations and slight thermal expansion). These ensure continuous operation of metallurgical equipment under high-temperature and heavy-load conditions.​

Mining Machinery Industry: Drive shafts of mining ball mills (suitable for Model 22330C5/W33, withstanding extreme thermal expansion and dust), main shafts of jaw crushers (suitable for Model 22324C4K, equipped with adapter sleeves, resisting vibration and moderate thermal expansion), and support shafts of vibrating screens (suitable for Model 22220C4, adapting to high-frequency vibration and moderate thermal expansion). These reduce bearing failure in mining equipment due to insufficient clearance.​

Chemical Industry: Drums of chemical drying equipment (suitable for Model 2226C5, withstanding high temperatures and extreme thermal expansion), agitator shafts of high-temperature reactors (suitable for Model 2222C4, compensating for installation deviations and moderate thermal expansion), and high-temperature chemical pumps (suitable for Model 2208C4/2RS, resisting humidity and moderate thermal expansion). These meet the transmission needs of chemical equipment in corrosive, high-temperature environments.​

Building Materials Industry: Support rolls of cement rotary kilns (suitable for Model 22344C5, withstanding extreme heavy loads and thermal expansion), conveyor belts of tile drying lines (suitable for Model 2214C3, compensating for installation deviations and slight thermal expansion), and rolls in the cooling section of glass melting furnaces (suitable for Model 2222C5, withstanding extreme thermal expansion). These ensure stable operation of building materials equipment in high-temperature production environments.​

General Heavy Machinery Industry: Main shafts of heavy-duty fans (suitable for Model 2216C3/2Z, withstanding slight thermal expansion and dry environments), impeller shafts of large water pumps (suitable for Model 2218C4, compensating for installation deviations and moderate thermal expansion), and output shafts of heavy-duty reducers (suitable for Model 2220C4, resisting impact and heavy loads). These adapt to high-temperature transmission scenarios in general heavy machinery.

V. Summary of Product Advantages
Triple Compatibility, Solving Complex Problems: High radial load capacity addresses heavy-duty requirements, wide play absorbs thermal expansion of the shaft system, automatic self-aligning compensates for angular deviations. The three characteristics work together to solve the combined problems of "heavy load + high temperature + deviation", avoiding bearing jamming and overload failure.
Strong Adaptability to Working Conditions: High toughness material, thick outer ring and heat dissipation groove design enable stable operation within a temperature range of -30°C to +180°C and a vibration acceleration of ≤12m/s², suitable for heavy-duty and high-temperature scenarios in multiple industries such as metallurgy, mining, and chemical engineering.
Convenient Installation and Maintenance: Compatible with standard double-row self-aligning ball bearing installation dimensions. The cone hole model can adjust the play through the locking sleeve without modifying the equipment structure; models with sealing and lubrication grooves reduce maintenance frequency, with a maintenance-free period of up to 15,000 - 25,000 hours, reducing equipment operation and maintenance costs.
Outstanding Cost Performance: Although the single set cost is 20% - 30% higher than the standard play type, it can significantly reduce equipment downtime failure rate (by more than 65%), extend bearing service life, and reduce overall costs from the equipment's entire life cycle, demonstrating a significant cost advantage.

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