Large Radial Clearance Single-row Self-aligning Ball Bearing

I. Product Overview​

Single-Row Self-Aligning Ball Bearings with Large Radial Clearance (abbreviated as SRSABB-LC) are a specialized category within the single-row self-aligning ball bearing family, designed specifically for scenarios characterized by significant thermal expansion, large installation deviations, and intense operational vibration. Their core competitiveness lies in the dual adaptability of "wide radial clearance + self-alignment" - they can not only compensate for angular deviations of 1°-3° in the shaft system (e.g., misaligned installation, shaft bending) through their spherical contact structure but also absorb thermal elongation of the shaft system caused by temperature rise via the expanded radial clearance (Grade C3/C4/C5). This prevents bearing seizure, overheating, or local overload failure due to insufficient clearance, making them key transmission components for solving complex working conditions involving "large temperature fluctuations + poor alignment".​

The outer diameter of these bearings ranges from 10mm to 400mm, with an inner diameter spanning 5mm to 200mm and a basic dynamic load rating of 2kN-200kN. They inherit the characteristic of single-row self-aligning ball bearings of "prioritizing radial load-bearing while supplementing axial load-bearing" (axial rated load accounts for 10%-25% of the radial rated load), eliminating the need for additional thrust bearings to meet light axial load requirements. The limiting speed under grease lubrication is 8,000-16,000 r/min, slightly lower than that of standard clearance models, primarily due to marginally reduced high-speed stability caused by expanded clearance. These bearings are suitable for general mechanical transmission systems in high-temperature, high-vibration industries such as metallurgy, mining, and chemical engineering.​

Compared with single-row self-aligning ball bearings with standard clearance (Grade CN), their radial clearance is expanded by 50%-150% (for example, for a bearing with an inner diameter of 50mm, the clearance of Grade C3 is 0.105-0.18mm, while that of Grade CN is only 0.065-0.115mm). Simultaneously, targeted optimizations have been made to material toughness and heat dissipation structures, enabling stable operation within a temperature fluctuation range of -30℃ to +150℃. The equipment downtime failure rate is reduced by over 60% compared to standard clearance models, making them particularly suitable for equipment operating in long-term high-temperature conditions or with limited installation accuracy.​

II. Core Structure and Design Features​

1. Precision Structural Composition​

The three core components of SRSABB-LC are optimized for "wide clearance adaptation, vibration resistance and wear resistance, and stable heat dissipation" to ensure reliable operation under complex working conditions:​

Inner Ring: Features a double 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 cylindrical and connected to the shaft via an interference fit. 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 60-64, 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., drying equipment), 17CrNiMo6 alloy carburized steel is adopted, improving high-temperature oxidation resistance by 40%.​

Outer Ring: The inner surface of the outer ring is a single 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 10%-15% thicker than that of standard clearance models (e.g., for a model with an inner diameter of 30mm, the outer ring wall thickness increases from 5mm to 5.8mm), 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 1.5mm-2mm, width 2mm-3mm), which can reduce operational temperature rise by 8-12℃. Models with lubrication grooves (suffix /W33) are equipped with 3 evenly distributed oil holes (diameter 3mm-6mm) on the outer ring, facilitating grease replenishment via high-pressure lubrication systems and extending maintenance intervals.​

Rolling Elements and Cage: The rolling elements are high-purity GCr15SiMn bearing steel balls, processed through "vacuum melting + precision grinding + nano-level polishing". The roundness error is ≤ 0.2μm, and the surface roughness is Ra ≤ 0.08μm, ensuring uniform contact with the spherical raceways and reducing local wear under wide clearance. Cages are divided into two types:​

For medium-low speed scenarios (rotational speed ≤ 12,000 r/min), stamped cages made of SPCC cold-rolled steel sheets are used, with galvanized surfaces for rust prevention, offering low cost and light weight;​

For medium-high speed scenarios (rotational speed ≤ 16,000 r/min), solid brass cages (HPb59-1) are adopted, providing excellent wear resistance and heat dissipation. The clearance between the cage pockets and steel balls is controlled at 0.15mm-0.25mm, preventing noise caused by steel ball movement during high-speed operation (no-load noise ≤ 55dB).​

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 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.​

Strong Self-Aligning and Deviation Resistance: The spherical raceway design of the outer ring allows angular deviations of 1°-3° in the shaft system, compensating for alignment issues caused by misaligned bearing housing installation (coaxiality error ≤ 0.2mm) and shaft bending after long-term operation (deflection ≤ 0.15mm/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 ≤ 10m/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 ≤ 40℃ (at an ambient temperature of 25℃) under high-temperature conditions (e.g., 120℃), preventing bearing damage due to lubricant failure.​

Low Maintenance and High Compatibility: Sealed models (suffix 2Z/2RS) prevent dust and impurities from entering - the 2Z suffix (double-sided steel dust covers) is suitable for dry, high-temperature environments (e.g., drying equipment); the 2RS suffix (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). Meanwhile, these bearings are compatible with the installation dimensions of standard single-row self-aligning ball bearings, allowing direct replacement of standard models without modifying the equipment structure, thus reducing upgrade costs.​

III. Clearance Grades and Parameter Specifications​

The clearance grades of SRSABB-LC are subdivided in accordance with ISO standards, with different clearance ranges corresponding to different inner diameter intervals. The specific parameters are as follows (unit: mm):

IV. Main Product Models and Classification​

1. Classification by Size and Clearance Grade​

Based on inner diameter and clearance grade, SRSABB-LC can be categorized as follows to accurately match different working condition requirements:

2. Classification by Seal and Installation Method​

Open Large-Clearance Self-Aligning Bearings (No Suffix): No sealing structure, requiring coordination with the equipment's built-in sealing system. Suitable for dry, high-temperature, and easy-to-maintain scenarios (e.g., auxiliary shafts of metallurgical rolling mills, high-temperature fans).​

Large-Clearance Self-Aligning Bearings with Dust Covers (Suffix 2Z): Double-sided steel dust covers block dust and debris, reducing grease consumption. Suitable for dry, high-temperature environments (e.g., drying equipment, heating furnace conveyor belts).​

Large-Clearance Self-Aligning Bearings with Contact Seals (Suffix 2RS): Double-sided nitrile rubber (NBR) seals, with an IP54 dust and water resistance rating. Suitable for humid, low-dust high-temperature scenarios (e.g., chemical pumps, hot rolls of printing and dyeing machines).​

Large-Clearance Self-Aligning Bearings with Lubrication Grooves (Suffix /W33): Annular lubrication groove + 3 oil holes on the outer ring, facilitating regular replenishment of high-temperature grease (e.g., lithium-based high-temperature grease, temperature resistance ≤ 180℃). Suitable for high-temperature equipment operating continuously for long periods (e.g., mining ball mills, large conveyor belts).

V. Applicable Industries and Typical Applications
The large radial clearance single-row self-aligning ball bearing, with its core advantages of "wide clearance for thermal expansion adaptation and emphasis on center resistance to deviation", is widely used in industrial fields with high temperatures, high vibrations, and limited installation accuracy. Typical scenarios include:
Metallurgical Industry: Auxiliary rollers for metallurgical rolling mills (compatible with model 1320C4, capable of withstanding moderate thermal expansion and vibration), conveyor belts for steel billet heating furnaces (compatible with model 1224C5/W33, resistant to extreme thermal expansion and dust), cooling section rollers of continuous casting machines (compatible with model 1218C3, compensating for installation deviations and slight thermal expansion), ensuring continuous operation of metallurgical equipment under high-temperature conditions.
Mining Machinery Industry: Support shafts for mining vibrating screens (compatible with model 1318C4, resistant to high vibration and moderate thermal expansion), transmission shafts for ball mills (compatible with model 1226C5/W33, resistant to dust and extreme thermal expansion), eccentric shafts for crushers (compatible with model 1324C4, compensating for shaft curvature and vibration), reducing bearing failure due to insufficient clearance in mining equipment.
Chemical Industry: Drum of chemical drying equipment (compatible with model 1222C5, resistant to high temperature and extreme thermal expansion), stirring shafts for reaction vessels (compatible with model 1316C3, compensating for installation deviations and slight thermal expansion), high-temperature chemical pumps (compatible with model 1208C4/2RS, resistant to humidity and moderate thermal expansion), meeting the transmission requirements of chemical equipment in corrosive and high-temperature environments.
General Machinery Industry: Main shafts of high-temperature fans (compatible with model 1210C3/2Z, resistant to slight thermal expansion and dry environment), impeller shafts of large water pumps (compatible with model 1312C4, compensating for installation deviations and moderate thermal expansion), support rollers of drying ovens (compatible with model 1220C5/W33, resistant to extreme thermal expansion and dust), suitable for high-temperature transmission scenarios of general machinery.
Building Materials Industry: Auxiliary support rollers for cement rotary kilns (compatible with model 1328C4, resistant to vibration and moderate thermal expansion), conveyor belts for ceramic drying lines (compatible with model 1214C3, compensating for installation deviations and slight thermal expansion), roller tracks for glass furnaces cooling section (compatible with model 1222C5, resistant to extreme thermal expansion), ensuring stable operation of building materials equipment in high-temperature production environments.
VI. Summary of Product Advantages
Dual Adaptation to Thermal Expansion and Deviation: Wide radial clearance (C3/C4/C5) absorbs shaft system thermal elongation, spherical structure compensates for 1° - 3° angular deviation, dually solving the "temperature fluctuation + alignment deficiency" combined problem, avoiding bearing jamming and overload failure.
Strong Adaptability to Working Conditions: High toughness material, thick outer ring and heat dissipation groove design, can operate stably within - 30°C to + 150°C temperature range and ≤ 10m/s² vibration acceleration conditions, suitable for high-temperature and high-vibration scenarios in metallurgy, mining, and chemical industries.
Convenient Installation and Maintenance: Compatible with standard single-row self-aligning ball bearing installation dimensions, can be directly replaced and upgraded; models with sealing and lubrication grooves reduce maintenance frequency, maintenance-free period can reach 10,000 - 20,000 hours, reducing equipment operation and maintenance costs.
Outstanding Cost Performance: Although the single set cost is 15% - 25% higher than standard clearance models, it can significantly reduce equipment downtime failure rate (reducing by 60% or more), extend bearing service life (extending by 50% or more), and reduce overall costs from the perspective of the equipment's entire life cycle.

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