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Self-Aligning Bearings

Self-Aligning Ball Bearings – Technical Overview

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IBSCO is a certified distributor and service provider of precision self-aligning ball bearings for commercial, military, aerospace, and industrial applications. We offer an extensive inventory of standard and custom self-aligning bearing solutions from the most trusted manufacturers in the industry, including:

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  • NHBB (New Hampshire Ball Bearings)

  • NMB (MinebeaMitsumi Group)

  • Barden

  • IJK

  • Timken

  • Torrington

  • Fafnir

 

Our product offering spans a wide range of bore sizes, cage materials, lubrication options, sealing configurations, and precision classes, making IBSCO a one-stop source for self-aligning bearing solutions that meet high-performance requirements and demanding environmental conditions.

 

What Are Self-Aligning Ball Bearings?

 

Self-aligning ball bearings are a specialized class of radial ball bearings designed to accommodate shaft misalignment and mounting errors without sacrificing rotation precision or bearing life. These bearings feature:

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  • Two rows of balls for increased radial load capacity.

  • A common spherical raceway in the outer ring that allows the inner ring (with its double raceways) to pivot within the housing.

  • The ability to correct for angular misalignment, typically up to ±3°, depending on size and manufacturer.

Internal Construction:

Component

Description

Spherical raceway allows for angular movement of the inner ring

Outer Ring

Contains two raceways for twin rows of balls; mounted directly to shaft

Inner Ring

Two rows of precision-grade balls reduce friction and distribute loads

Ball Set

Maintains ball spacing; available in pressed steel, machined brass, or polymer

Cage (Retainer)

Types of Misalignment Tolerated:

  • Static Misalignment: Caused by installation errors or frame distortion.

  • Dynamic Misalignment: Occurs during operation due to shaft bending, load changes, or thermal expansion.

 

Real-World Examples:

  • In HVAC blower systems, misalignment from shaft bowing due to temperature changes is common. Self-aligning bearings maintain optimal load distribution and prevent localized wear.

  • In agricultural machinery, shafts mounted across long spans may sag during operation. Self-aligning bearings absorb this misalignment and preserve bearing performance.

Performance Characteristics:

Parameter

Typical Range / Notes

Up to ±3°

Misalignment Angle

10,000–20,000 RPM depending on seal, size, lubrication

Speed Capability

Moderate (better than single-row deep groove bearings)

Radial Load Capacity

Low – not suitable for pure axial loads

Axial Load Capacity

Extended when misalignment is properly managed

Service Life

Types & Configurations

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IBSCO supplies all major configurations of self-aligning ball bearings, including:

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1. Open Type

  • Allows for visual inspection and external lubrication.

  • Highest speed capability due to minimal contact friction.

  • Typical Use: Low-contamination environments such as textile looms or large-scale printers.

 

2. Sealed Type (Contact/Non-Contact)

  • Integrated seals retain grease and exclude moisture and contaminants.

  • Available with nitrile, fluoroelastomer (FKM), or PTFE seal materials.

  • Typical Use: Food processing, packaging lines, washdown environments.

 

3. Cylindrical Bore

  • Fits directly on standard diameter shafts via interference or slip fit.

  • Common in applications with stable shaft alignment and precise fits.

  • Typical Use: Electric motors, centrifugal pumps.

 

4. Tapered Bore (1:12 or 1:30 taper)

  • Mountable using adapter or withdrawal sleeves for flexible axial positioning.

  • Facilitates fine adjustment of bearing clearance during installation.

  • Typical Use: Large fans, conveyor drums, and heavy-duty pillow blocks.

 

Materials and Cages

The choice of material directly affects the performance, durability, and corrosion resistance of the bearing.

Bearing Ring Materials:

Material

Characteristics

Use Case Example

SAE 52100 Chrome Steel

High hardness, fatigue resistance, lower corrosion resistance

General industrial applications

AISI 440C Stainless

Hardened stainless with good corrosion resistance

Food, medical, marine, aerospace environments

AISI 304/316 Stainless

Soft stainless; excellent corrosion resistance, low wear

Light-load applications in corrosive atmospheres

Cage Options:

  • Steel Cages: High-speed, high-strength applications

  • Machined Brass Cages: Superior shock resistance; ideal for vibration-prone environments

  • Polyamide/Nylon Cages: Lightweight, quiet, and cost-effective; best for moderate speeds

Technical Specifications

Feature

Range / Options

5 mm to 120 mm+ (standard); custom sizes available

Bore Diameter Range

19 mm to 230 mm+

Outer Diameter Range

ABEC 1, 3, 5, 7 (ISO P0–P4)

Precision Classes

C2 (tight) to C5 (loose); C3 is most common for general use

Clearance Options

Up to 15,000 RPM (varies by size and seal type)

Max Speed (Grease)

-40°C to +150°C (standard); up to 250°C with special grease

Operating Temperature

Grease, oil, dry film, solid lubricants (per application)

Lubrication

Typical Applications


Self-aligning ball bearings are ideal for applications where shaft misalignment is inherent or unavoidable due to system design or dynamic loads.

Industry

Application Example

Benefits of Self-Aligning Design

Aerospace

Flight actuators, power generators

Reduces misalignment-induced fatigue

Military Systems

Targeting systems, drive systems

Reliable in high-vibration environments

Food Processing

Conveyor rollers, mixers

Stainless options available; low maintenance

Paper Mills

Roller assemblies, slitters

Handles thermal expansion and shaft deflection

HVAC & Fans

Impeller shafts, motor mounts

Tolerates misalignment due to thermal loads

Agricultural Equipment

Mowers, balers, combines

Resists shaft deflection from uneven terrain

IBSCO Value-Added Services

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To support our customers’ complete lifecycle needs, IBSCO offers a full suite of certified value-added services, including:

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Clean Room Lubrication

  • AS9100-compliant Class 6 clean room

  • Precision grease packing (±0.5mg control)

  • Vacuum impregnation of cages to reduce lubricant leaching

  • Food-grade, aerospace-approved, or low outgassing lubricants available

 

Customization & Support

  • Specialized seals: high-temp, low-torque, PTFE contact/non-contact

  • Duplex matching and axial preload setup

  • Product serialization and custom packaging

  • Private labeling and documentation per customer requirements

 

Supply Chain & Logistics

  • JIT and Kan-Ban inventory systems

  • Multi-year contracts and long-term agreements (LTAs)

  • Full traceability and certification documentation (C of C, material certs, DFARS, RoHS, etc.)

 

Certifications and Quality Assurance

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All IBSCO bearing products and services comply with the following standards:

  • AS9100 – Aerospace Quality Management

  • AS9120 – Aerospace Distribution Quality

  • ISO 9001 – General Quality Management

  • FDA, USDA, and NSF compliant bearing options available

  • Full DFARS, REACH, and RoHS compliance support where applicable

 

Contact IBSCO

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With over 40 years of experience and direct relationships with leading bearing OEMs, IBSCO is uniquely positioned to supply, support, and service self-aligning bearing needs across demanding sectors. Contact us to speak with a technical specialist or request a quote tailored to your application requirements.

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