Single Row Self-aligning Ball Bearing

I. Product Overview​

Single-Row Self-Aligning Ball Bearings (abbreviated as SRSABB) are the most widely used basic category in the self-aligning ball bearing family, with their core advantage lying in "self-aligning capability". Through the spherical contact structure between the inner ring and rolling elements, they can automatically compensate for angular deviations in the shaft system caused by installation errors, shaft deformation, or misaligned bearing housings (allowing an alignment angle of 1°-3°). This prevents local overload on the bearing, making them key transmission components for scenarios with "poor shaft system alignment".​

The outer diameter of these bearings typically ranges from 10mm to 400mm, and the inner diameter covers 5mm to 200mm. Structurally, they adopt a special design of "inner ring with double spherical raceways + outer ring with spherical raceway + steel balls". Primarily designed to bear radial loads, they can also withstand small bidirectional axial loads (axial rated load is approximately 10%-25% of the radial rated load), with a basic dynamic load rating of 2kN-200kN. They are suitable for general machinery fields prone to shaft system deviations, such as motors, pumps, and textile machinery.​

Compared with deep-groove ball bearings, single-row self-aligning ball bearings have a slightly lower limiting speed (grease-lubricated limiting speed: 8,000-18,000 r/min). However, their spherical contact design significantly improves adaptability to shaft system deviations, enabling long-term stable operation under conditions of limited installation accuracy and easily bent shafts. This reduces early bearing failure caused by misalignment issues, lowering the failure rate by more than 40% compared to ordinary deep-groove ball bearings.​

II. Core Structure and Design Features​

1. Precision Structural Composition​

The three core components of single-row self-aligning ball bearings are optimized for "self-alignment and stable force transmission" to ensure reliable operation under shaft system deviation conditions:​

Inner Ring: Adopts a double spherical raceway structure. The outer surface of the inner ring consists of two symmetrical spherical arcs, forming point contact with the steel balls. The inner bore of the inner ring is a cylindrical surface, connected to the shaft via an interference fit. The preferred material is SUJ2 high-carbon chromium bearing steel, which undergoes integral quenching and ultra-precision grinding. The surface hardness reaches HRC 60-64, and the raceway surface roughness is Ra ≤ 0.1μm, ensuring smooth contact with the steel balls. For scenarios requiring high strength, carburized steel (20CrMnTi) is used, which increases core toughness by 30% and enhances impact resistance.​

Outer Ring: The inner surface of the outer ring features a single spherical raceway, with the center of the spherical curvature coinciding with the bearing axis. This provides a "moving space" for the steel balls to swing around the axis, serving as the core structure for realizing self-aligning functionality. The outer diameter of the outer ring is a cylindrical surface, fitted with the bearing housing via a transition fit. Made of the same material as the inner ring, its wall thickness is 15%-20% thicker than that of deep-groove ball bearings, improving deformation resistance and preventing outer ring cracking caused by shaft system deviations. Some models are equipped with lubricating grooves and oil holes on the outer ring (marked with suffix /W33), facilitating grease replenishment and extending the maintenance interval.​

Rolling Elements and Cage: The rolling elements are high-purity steel balls, made of GCr15SiMn bearing steel, processed through vacuum degassing and precision grinding. The roundness error is ≤ 0.2μm, ensuring uniform contact with the spherical raceways. The cage is either a stamped steel cage (SPCC cold-rolled steel sheet) or a solid brass cage:​

Stamped cages are suitable for medium-low speed scenarios (rotational speed ≤ 12,000 r/min), offering light weight and low cost;​

Solid brass cages are suitable for medium-high speed scenarios (rotational speed ≤ 18,000 r/min), providing excellent wear resistance and heat dissipation.​

The clearance between the cage pockets and steel balls is controlled at 0.1mm-0.2mm, preventing noise caused by steel ball movement during high-speed operation.​

2. Key Design Characteristics​

Strong Self-Aligning Capability: Through the cooperation of the outer ring's spherical raceway and the inner ring's double spherical raceways, the shaft system is allowed to have an angular deviation of 1°-3° (depending on the bearing model: ≤ 3° for small bearings, ≤ 1.5° for large bearings). This compensates for misalignment issues caused by installation errors (e.g., misaligned bearing housings), shaft bending deformation, or equipment vibration, avoiding local wear on the bearing raceways and extending service life.​

Radial Load Bearing as Primary, Axial Load Bearing as Secondary: The core load-bearing direction is radial. Although the basic dynamic load rating is slightly lower (about 10%-15% lower) than that of deep-groove ball bearings of the same size, the axial load-bearing capacity can meet light axial load requirements (e.g., slight axial movement of motor shafts). No additional thrust bearings are needed, simplifying the transmission structure.​

Adaptability to Harsh Installation Conditions: It has low requirements for installation accuracy. Even with a bearing housing parallelism error of ≤ 0.1mm/m and coaxiality error of ≤ 0.2mm, it can still operate normally. It is suitable for equipment with limited installation accuracy, such as cast bearing housings and welded frames, reducing equipment processing and installation costs.​

Low Maintenance and High Stability: The spherical contact structure ensures uniform force distribution, resulting in low vibration (vibration acceleration ≤ 5m/s²) and low noise (no-load noise ≤ 55dB). Some sealed models (e.g., double-sided dust covers 2Z, double-sided contact seals 2RS) can block dust and impurities, achieving a maintenance-free period of 10,000-20,000 hours under normal working conditions.​

III. Main Product Models and Classification​

1. Classification by Size and Load Rating​

Based on outer diameter and load-bearing capacity, single-row self-aligning ball bearings can be categorized as follows to adapt to different load scenarios:

2. Classification by Seal and Lubrication Method​

Open Single-Row Self-Aligning Ball Bearings (No Suffix): No sealing structure, requiring coordination with the equipment's built-in sealing system. Suitable for dry, clean, and easy-to-maintain scenarios (e.g., machine tool spindles, precision gearboxes).​

Single-Row Self-Aligning Ball Bearings with Dust Covers (Suffix 2Z): Double-sided steel dust covers block dust and debris, reducing grease consumption. Suitable for equipment in dry environments such as motors and fans.​

Single-Row Self-Aligning Ball 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 scenarios (e.g., water pumps, textile machinery).​

Single-Row Self-Aligning Ball Bearings with Lubricating Grooves (Suffix /W33): The outer ring is equipped with an annular lubricating groove and 3 evenly distributed oil holes, facilitating continuous grease replenishment. Suitable for equipment operating continuously for long periods (e.g., conveyor rollers, printing machines).​

IV. Applicable Industries and Typical Applications​

With the core advantages of "self-alignment and adaptability to shaft system deviations", single-row self-aligning ball bearings are widely used in general machinery, light industry, heavy industry, and other fields. Typical applications include:​

General Machinery Industry: Small and medium-sized motors (e.g., Y-series three-phase asynchronous motors, suitable for Model 1310), centrifugal pumps (e.g., ISG pipeline pumps, suitable for Model 1206), and reducers (e.g., RV-series worm reducers, suitable for Model 1204). These address issues such as motor shaft extension bending and pump shaft installation deviations.​

Textile Machinery Industry: Roller shafts of textile machines (suitable for Model 1212) and fabric guide rollers of printing and dyeing machines (suitable for Model 1314). These adapt to shaft deformation and frame vibration of textile machinery after long-term operation, ensuring stable fabric transmission.​

Mining and Construction Machinery Industry: Drive shafts of small crushers (suitable for Model 1318) and support shafts of vibrating screens (suitable for Model 1220). These withstand shaft system deviations caused by equipment vibration, reducing frequent bearing replacements.​

Light Industry and Home Appliance Industry: Dehydration bucket shafts of washing machines (suitable for Model 1208) and impeller shafts of fans (suitable for Model 1308). These lower the installation accuracy requirements for home appliances, controlling production costs.​

Agricultural Machinery Industry: Gearbox shafts of tractors (suitable for Model 1316) and conveyor chain shafts of harvesters (suitable for Model 1214). These adapt to the 颠簸 of agricultural machinery during outdoor operations and changes in shaft system alignment, improving equipment reliability.

V. Summary of Product Advantages
Automatic centering and deviation compensation: It can compensate for 1° - 3° of shaft system angle deviation, solve the alignment problems caused by installation errors and shaft deformation, avoid local overload of bearings, extend service life, and reduce equipment maintenance costs.
Low installation accuracy requirements: No need for high-precision bearing housings and shaft processing. It is compatible with low-cost structural components such as casting and welding, reducing the difficulty of equipment manufacturing and installation, and improving production efficiency.
Stable operation, low failure rate: The spherical contact structure ensures uniform force distribution, low vibration and low noise. It can still operate stably under harsh conditions, with a failure rate reduced by more than 40% compared to ordinary deep groove ball bearings.
High cost performance, wide adaptability: The production process is mature, and the cost is close to that of deep groove ball bearings. It covers light, medium and heavy load scenarios, and does not need to customize bearings for different deviation conditions. It meets the general mechanical needs of multiple industries.

Hot Tags: single row self-aligning ball bearing, China single row self-aligning ball bearing manufacturers, suppliers, factory