Definition & Components
Insert bearings – also known as radial insert ball bearings, wide inner ring bearings, or Y-bearings – are single-row, ready-to-fit units comprising a solid outer ring and an inner ring extended on one or both sides. They are based on sealed deep groove ball bearings in the 62 and 63 series. The outer ring has a convex spherical shape that seats in pillow block or flange housings. The inner ring is extended to accommodate a locking device, enabling quick mounting onto straight cylindrical shafts without press-fitting.
Bearings with an inner ring extended on both sides run more smoothly, as the inner ring tilts less on the shaft. The spherical outer surface allows static initial misalignment by tilting within the housing, compensating for shaft deflection and mounting inaccuracies. Each unit is pre-lubricated and sealed, ready for installation. Misalignment between bearing and housing axis should not exceed 5°.
Features & Advantages
- Rapid mounting – Locking devices (set screws, eccentric collars, or adapter sleeves) are tightened with standard tools. No housing machining or press-fitting required.
- Misalignment tolerance – The spherical outer ring tilts within the housing to accommodate initial shaft deflection and mounting deviations.
- Contaminant resistance – Multi-labyrinth seals, rubber contact seals, or combined designs protect against dust and moisture while retaining lubricant.
- Smooth operation – Precision-ground raceways and high-grade balls reduce noise and vibration.
- Standardised dimensions – Metric and inch bore sizes follow international standards, ensuring interchangeability across manufacturers.
Your Professional Insert Bearing Manufacturer
DUHUI Bearing, founded in 2003 in Zhejiang, China, is a specialised factory dedicated to insert bearings. With over 20 years of experience, we manufacture more than 400 standard models across multiple series. Our insert bearing series include UC, SA, SB, UK, UE, and UEL, covering bore diameters from 12mm to 200mm. We also support custom designs per your specifications.
What Is an Insert Bearing?
Insert bearings, also known as Y-bearings, are based on sealed deep groove ball bearings. They feature a convex outer ring and an extended inner ring with a specific locking device. The spherical outer surface accommodates initial misalignment when fitted into a housing. This design enables quick mounting onto the shaft.
Locking Styles by Series – Choose the Right Fit
Each series is engineered with one locking system. This allows you to select the right bearing for your mounting requirements.
- Set screw locking – applied to UC, SA, and SB series. Two set screws on the extended inner ring lock the bearing firmly onto the shaft. This is the most common and cost-effective choice for general-purpose applications.
- Adapter sleeve locking – used for UK series. A tapered sleeve is drawn between the shaft and the bearing bore using a lock nut. The fit is tighter and more concentric. This design suits larger shafts and heavier load conditions.
- Eccentric locking collar – featured in UE and UEL series. A half-offset collar is turned to wedge the bearing onto the shaft. This provides a more concentric grip. Recommended for reversing loads or vibrating conditions.
Materials, Sealing and Heat Treatment
All insert bearings use GCR15 bearing steel as the base material. Raceways are precision-ground and superfinished to reduce friction and noise. Sealing options range from single-lip to triple-lip designs, all with full metal shrouds for contamination protection in harsh environments. Heat stabilisation S1 (up to 200 C) and S2 (up to 250 C) are available for high-temperature applications. Surface treatments include shot peening for fatigue strength, carburising for surface hardness while retaining core toughness, and anti-corrosion coating for extended service life. These options extend service life in specific operating environments.
Quality Assurance
DUHUI holds ISO 9001 and IATF 16949 certifications. Our in-house laboratory performs dimensional accuracy, radial clearance, noise, and vibration tests on every batch. Precision meets ABEC1 (P0) with C3 and C4 internal clearances optional. Complaint rate stays below 0.5%, backed by strict process control from raw material inspection to final assembly.
Why Choose DUHUI for Insert Bearings
We manufacture in our own 10,000 m2 facility with a monthly output of 100,000 sets. Standard orders ship within 15 to 45 days; custom prototypes can be delivered within 30 days. Our products are exported to Europe, North and South America, and the Middle East. We provide a 2-year or 50,000-km warranty on all standard products, with technical support available for installation and troubleshooting.
Applications and Custom Support
Our insert bearings serve agricultural machinery, conveyor systems, mining equipment, packaging lines, and industrial gearboxes. We support OEM, ODM, and private-label orders. Custom bore sizes, special coatings, and series modifications can be developed per your drawings. Packaging options include standard export cartons, neutral packaging, or branded boxes per your requirements. Contact us for catalogues, samples, or technical data. DUHUI Bearing – your professional insert bearing manufacturer since 2003.
Types and Series
Insert bearings are classified by their locking mechanism. Each series is designed with a specific locking system. The following sections present the standard series designations by locking method, with 200 series for standard duty and 300 series for heavy duty applications.
- Insert Bearing Types
- Insert Bearing Series
Insert Bearing Types – By Locking Method
Insert bearings are classified into three primary locking methods. Each offers distinct advantages for specific operating conditions. The following series represent the standard insert bearing range, organised by locking mechanism. Each series is manufactured from GCR15 bearing steel with precision-ground raceways.
One or two set screws in the extended inner ring are tightened directly against the shaft using a hexagonal key. The most common locking method, suitable for light- to medium-duty applications with steady loads. UC series features inner ring extended on both sides; SB series features narrow inner ring design for space-constrained applications.
A tapered sleeve (1:12 taper) is driven between the shaft and the bearing bore using a lock nut and lock washer. Provides 360° concentric clamping force without shaft damage. Ideal for reversing loads, heavy vibration, and shafts without shoulders.
A cam-action collar is rotated in the direction of shaft rotation to lock the bearing. Offers uniform grip without shaft damage, commonly used where vibration is moderate. UEL series features extended inner ring for enhanced shaft support; UE series features flat head design.
Insert Bearing Series – By Duty Rating
The table below cross-references each locking method with its corresponding series designation, and further distinguishes between 200 series (standard duty) and 300 series (heavy duty) variants.
200 Series (Standard Duty) — Standard load capacity for general industrial applications including conveyors, fans, and agricultural equipment.
300 Series (Heavy Duty) — Enhanced load capacity and robust construction for demanding applications with higher loads, vibration, and reversing conditions.
| Locking Method | Series | 200 Series (Standard Duty) | 300 Series (Heavy Duty) |
| Set Screw Locking | UC | UC200 | UC300 |
| Set Screw Locking | SA | SA200 | SA300 |
| Set Screw Locking | SB | SB200 | SB300 |
| Adapter Sleeve Locking | UK | UK200 | UK300 |
| Eccentric Collar Locking | UE | UE200 | UE300 |
| Eccentric Collar Locking | UEL | UEL200 | UEL300 |
Other Related Bearing Types
The following bearing types are commonly used in automotive driveline and wheel-end applications. Although they are not insert bearings in the strict sense, they are often referenced alongside them in product portfolios.
Single-row or double-row ball or tapered roller bearings pressed directly into the steering knuckle or hub. No integrated flange; the hub and bearing are separate components. Used in many passenger car rear axles and some front axles.
Pre-assembled units that integrate the bearing, hub flange, and (in Gen 3) an ABS sensor ring. Bolted directly to the steering knuckle, reducing assembly complexity and improving stiffness. Common in modern FWD and SUV applications.
Axial-load bearings (also called throw-out bearings) that actuate the clutch diaphragm spring in manual transmissions. Designed for high axial thrust and rapid engagement cycles.
Bearings that support the centre of a two-piece driveshaft in rear-wheel-drive and truck applications. Accommodate shaft misalignment and dampen driveline vibrations.
Industry Applications
Insert bearings are specified across a broad range of industries. The following lists key sectors and typical equipment where these products are installed.
Assembly line rollers, conveyor systems, powertrain test rigs, suspension components, steering linkages, and auxiliary drives where compact, sealed bearings are required.
Combine harvesters, balers, tillage equipment, and sprayers. Demanding environments require enhanced sealing against dust, soil, and moisture.
Belt conveyors, roller conveyors, bucket elevators, and palletisers. Take-up units maintain belt tension and track alignment.
Stainless-steel housings and food-grade lubricants are used in wash-down areas. Bearings must resist corrosion and frequent cleaning cycles.
Industrial pumps, HVAC fans, and blowers. Reliable operation and low maintenance are key selection factors.
Crushers, screens, and heavy-duty conveyors. Robust housings and sealing handle high loads and abrasive contaminants.
Product Comparison
The following internal article compares UC series (set screw locking) with UK series (adapter sleeve locking) insert bearings, helping engineers choose based on load, vibration, and shaft conditions.
UC bearings use set screws for quick installation, suitable for moderate loads and steady operation. UK bearings employ a tapered sleeve and lock nut, providing 360° clamping force without shaft damage. Ideal for reversing loads, high vibration, and shafts without shoulders. This article details torque specifications, shaft preparation, and application examples for each type.
For more details, please read“ UC vs UK”
Related Products
The following insert bearings represent commonly specified models across industrial applications. For specific dimensional, load, and sealing requirements, refer to the product data sheet of each model.
SB306SB306 — Heavy-duty narrow inner ring set screw locking insert bearing for 30mm shaft. Two set screws at 120° angle for secure shaft attachment. Suitable for demanding confined installations.
SB307SB307 — Heavy-duty narrow inner ring set screw locking insert bearing for 35mm shaft. Robust construction with self-aligning capability. For heavy industrial equipment with space constraints.
SB308SB308 — Heavy-duty narrow inner ring set screw locking insert bearing for 40mm shaft. Maximum capacity in SB300 series. Suitable for heavy loads in limited axial space applications.
UK205UK205 — Adapter sleeve locking insert bearing for 20mm shaft with H2305 adapter sleeve. Higher load capacity than UC series. Self-aligning spherical outer diameter.
UK206UK206 — Adapter sleeve locking insert bearing for 25mm shaft with H2306 adapter sleeve. Tapered bore design for secure shaft mounting. Suitable for moderate to heavy loads.
UK208UK208 — Adapter sleeve locking insert bearing for 35mm shaft with H2308 adapter sleeve. High-capacity standard duty bearing. Self-aligning design compensates for shaft misalignment.
UK305UK305 — Heavy-duty adapter sleeve locking insert bearing for 20mm shaft with HE2305 adapter sleeve. Higher speed and load capacity than UC300 series. For vibration and shock load applications.
UK306UK306 — Heavy-duty adapter sleeve locking insert bearing for 25mm shaft with HE2306 adapter sleeve. Tapered bore design requires H2300 series adapter sleeve. Suitable for heavy industrial equipment.
UK308UK308 — Heavy-duty adapter sleeve locking insert bearing for 35mm shaft with HE2308 adapter sleeve. Maximum capacity in UK300 series. For heavy loads, vibration, and shock conditions.
UE204UE204 — Eccentric locking collar insert bearing with flat head for 20mm shaft. Positive shaft locking through eccentric collar rotation. Suitable for conveyors and reversing load applications.
UE205UE205 — Eccentric locking collar insert bearing with flat head for 25mm shaft. Standard duty design with self-aligning spherical outer ring. Pre-lubricated and sealed for maintenance-free operation.
UE206UE206 — Eccentric locking collar insert bearing with flat head for 30mm shaft. Double-lip seals provide contamination protection. For agricultural equipment and general industrial applications.
UE305UE305 — Heavy-duty eccentric locking collar insert bearing with flat head for 25mm shaft. Enhanced load capacity for demanding applications. Robust construction for vibration and shock loads.
UE306UE306 — Heavy-duty eccentric locking collar insert bearing with flat head for 30mm shaft. Wide inner ring design for improved shaft support. Suitable for heavy agricultural and industrial equipment.
UE307UE307 — Heavy-duty eccentric locking collar insert bearing with flat head for 35mm shaft. High-capacity bearing for severe operating conditions. Spherical outer ring enables self-alignment.
UEL204UEL204 — Eccentric locking collar insert bearing for 20mm shaft with extended inner ring. Positive shaft locking for reversing load and vibrating conditions. Pre-lubricated and ready for installation.
UEL205UEL205 — Eccentric locking collar insert bearing for 25mm shaft with extended inner ring. Enhanced shaft support through extended inner ring design. Suitable for agricultural and conveyor applications.
UEL206UEL206 — Eccentric locking collar insert bearing for 30mm shaft with extended inner ring. Robust locking mechanism for vibration resistance. Self-aligning spherical outer ring compensates for misalignment.
UEL306UEL306 — Heavy-duty eccentric locking collar insert bearing for 30mm shaft with extended inner ring. Wide inner ring for improved shaft support. Suitable for heavy agricultural and industrial equipment.
UEL307UEL307 — Heavy-duty eccentric locking collar insert bearing for 35mm shaft with extended inner ring. High-capacity bearing for vibration and shock loads. Spherical outer ring enables self-alignment.
UEL308UEL308 — Heavy-duty eccentric locking collar insert bearing for 40mm shaft with extended inner ring. Maximum capacity in UEL300 series. For heavy conveyors and demanding industrial applications.
Insert Bearings – How to Choose: Set Screw, Eccentric Collar, or Adapter Sleeve?
Ever had a bearing fail because the shaft got scored by set screws? Or struggled with alignment because the housing bore wasn’t machined correctly? These are everyday challenges in industrial maintenance.
Insert bearings solve these problems. They combine the bearing, locking mechanism, and sealing into a single, ready-to-mount unit. You don’t need to machine housing bores or press-fit bearings. You just slide the unit onto the shaft, lock it, and you’re done.
This guide covers what insert bearings are, how they work, how to choose the right one, and what to do when things go wrong. Whether you’re an engineer, a maintenance professional, or a procurement specialist, you’ll find practical selection criteria and troubleshooting guidance.
What Is an Insert Bearing?
Insert bearings – also called radial insert ball bearings, wide inner ring bearings, or Y-bearings – are designed for quick shaft mounting without press fits. Their spherical outer surface self-aligns within the housing to compensate for misalignment, while the extended inner ring provides space for a mechanical locking device—set screws, an eccentric collar, or an adapter sleeve. These bearings trace their dimensions to the 62 and 63 series deep-groove ball bearings.
The spherical outer surface fits into a matching concave housing bore. This ball-and-socket arrangement allows the bearing to accommodate initial misalignment – up to 5° for non-relubricatable bearings and 2° for relubricatable bearings – by tilting in the housing. This makes insert bearings exceptionally forgiving of shaft deflection and mounting imperfections.
The extended inner ring provides space for the locking mechanism – set screws, an eccentric collar, or an adapter sleeve. Instead of requiring a press fit, an insert bearing slips onto the shaft with a clearance fit and locks in place mechanically.
Insert bearings are supplied pre-greased and sealed, ready for installation. Bearings with an inner ring extended on both sides run more smoothly, as the extent to which the inner ring can tilt on the shaft is reduced.
Core Components
An insert bearing system consists of three core elements:
- The Bearing Insert – A deep groove ball bearing, typically with C3 or greater internal clearance to accommodate thermal expansion and minor misalignments. The extended inner ring provides the surface for the locking device.
- The Locking Mechanism – The defining feature that securely fastens the bearing onto a straight cylindrical shaft. Available in set screw, eccentric collar, and adapter sleeve types.
- The Sealing System – Effective sealing is critical. Modern insert bearings feature multi-labyrinth seals, rubber contact seals (e.g., NBR, FKM), or a combination of both. These seals protect against contaminants and retain lubricant, significantly extending service intervals.
Locking Mechanisms Compared
The locking mechanism is one of the most critical factors in insert bearing selection. The various insert bearing series differ in the way the bearing is locked onto the shaft: with set screws, with an eccentric locking collar, or with an adapter sleeve.
Set Screw Locking (UC, SA, SB) – The extended inner ring has one or two threaded holes. Set screws are tightened against the shaft using a hex key. This method is fast and economical, but it creates point-load indentations on the shaft. Suitable for moderate speeds and steady loads. The two set screws are positioned 62° apart for UC series bearings and 120° apart for SA and SB series.
Eccentric Locking Collar (UE, UEL) – A collar with an eccentric cam is placed over the inner ring and rotated in the direction of shaft rotation. The eccentric diameters of both collar and inner ring fully engage to lock the bearing. Provides more uniform clamping than set screws and avoids shaft damage. However, the locking direction must match the rotation.
Adapter Sleeve Locking (UK) – A tapered sleeve (1:12 taper) is driven between the shaft and the bearing bore using a lock nut and lock washer. Provides 360° concentric clamping force without shaft damage. Recommended for reversing loads, heavy vibration, shafts without shoulders, and applications where shaft fretting corrosion must be prevented.
Concentric vs. Eccentric Locking
One key factor often overlooked: set screw locking introduces eccentricity between the shaft and the inner ring. Eccentric collar locking also introduces eccentricity, but to a lesser extent.
Any eccentricity in the system can lead to unwanted vibration during operation. For applications where vibration is a concern – high-speed operation, precision machinery – adapter sleeve locking (UK series) is the better choice. It creates a 360° concentric grip on the shaft, reducing vibration and allowing for possible increases in rotational speed.
Locking Mechanism Quick Reference
| Locking Type | Series | Shaft Damage | Eccentricity | Best For |
|---|---|---|---|---|
| Set Screw | UC, SA, SB | High (indentations) | Yes | General MRO, moderate speeds |
| Eccentric Collar | UE, UEL | Low | Minor | Quick axial positioning, constant rotation |
| Adapter Sleeve | UK | None | No | High speed, vibration, reversing loads |
Series Classifications and Naming
Insert bearings are classified by series designation, which indicates both locking method and duty rating. The table below summarizes how each series locks onto the shaft:
| Series | Locking Method | Duty Rating | Key Feature |
|---|---|---|---|
| UC200 / UC300 | Set Screw | 200: Standard / 300: Heavy | Inner ring extended both sides |
| SA200 / SA300 | Set Screw | 200: Standard / 300: Heavy | Standard configuration |
| SB200 / SB300 | Set Screw | 200: Standard / 300: Heavy | Narrow inner ring |
| UK200 / UK300 | Adapter Sleeve | 200: Standard / 300: Heavy | 1:12 tapered bore |
| UE200 / UE300 | Eccentric Collar | 200: Standard / 300: Heavy | Flat head design |
| UEL200 / UEL300 | Eccentric Collar | 200: Standard / 300: Heavy | Extended inner ring |
200 series denotes standard duty; 300 series denotes heavy duty with enhanced load capacity.
Understanding the Naming Convention
Take UCP210 as an example:
- UC = Insert series (set screw locking)
- P = Housing type (pillow block)
- 210 = Bore size code (50mm bore), with “2” indicating 200 series
The full designation tells you both the bearing series and the housing style in one code. This standardized naming is recognised globally and cross-referenced across brands.
How to Select the Right Insert Bearing
Selection often starts with shaft size and housing compatibility. But operating conditions also play a major role. Here’s a practical framework:
Selection Cheatsheet
- Radial load dominant; small misalignment → Insert bearing is appropriate. Verify the misalignment rating (5° for non-relubricatable, 2° for relubricatable).
- Locking choice → Set screw (UC/SA/SB) for simplicity and MRO; eccentric (UE/UEL) for quick axial location; adapter sleeve (UK) for better balance at speed and reduced shaft damage.
- Harsh washdown or caustic environment → Choose sealed housings, deflectors, cleaner-compatible grease, and corrosion-resistant surfaces.
- High vibration → Prefer adapter sleeve (UK) locking; check for creep and consider mechanical stops.
- Significant axial load → Move to angular-contact or tapered roller bearings in a housed assembly.
Environment-Attributes Matrix
| Environment | Housing / Coating | Locking Preference | Sealing | Lubricant |
|---|---|---|---|---|
| Washdown / Food | Stainless or coated rings; hygienic housings | Adapter sleeve (UK) | 2RS + deflectors | NSF H1 grease |
| Abrasive / Dusty | Coated rings; hard surfaces | Adapter sleeve (UK) | 2RS or shield + labyrinth | Heavy-duty grease |
| High Humidity / CIP | Chromium-family coatings | Adapter sleeve (UK) | Sealed + external deflectors | H1 grease |
| High Vibration | Coated contact surfaces | Adapter sleeve (UK) | 2RS + slingers/deflectors | Film-persistent grease |
Six Selection Criteria
When specifying an insert bearing, evaluate these factors:
- Shaft diameter – Select the correct bore size (metric or inch) and ensure a slip-fit. Recommended shaft tolerance classes are h6 to h9.
- Load magnitude and direction – Consider radial, axial, and combined loads. Insert bearings primarily support radial loads with limited axial capacity.
- Operating speed – Higher speeds may require better balancing and tighter clearance control. Adapter sleeve (UK) locking is preferred for high-speed operation.
- Environmental conditions – Dust, moisture, chemicals, and temperature extremes dictate seal type and housing material.
- Vibration levels – High vibration favours adapter sleeve (UK) or eccentric collar (UE/UEL) locking.
- Maintenance strategy – Set screw (UC/SA/SB) locking offers quick removal; adapter sleeve (UK) locking offers long-term reliability.
Shaft Fit and Housing Setup
Insert bearings are designed for slip-fit mounting onto shafts, not interference fits. These bearings are designed to locate the shaft axially; they do not permit relative axial movement between the shaft and housing. The distance between bearing positions should therefore be short to avoid excessive induced axial loads as a result of thermal expansion of the shaft.
Shaft fit is typically slip-fit with locking; verify OEM guidance. Ensure the spherical seat can align freely.
Temperature Limits
The permissible operating temperature for NBR seals is -30°C to +100°C. Temperatures up to 120°C can be tolerated for brief periods. For higher temperatures, specialty seals (e.g., FKM) or high-temperature bearing variants are available.
Common Failure Modes and Troubleshooting
Understanding how insert bearings fail helps you diagnose problems early and prevent unplanned downtime. Below are four common failure patterns, their symptoms, root causes, and recommended corrective actions.
1. Corrosion – Pitting, Crevice Rust, or Staining
- Symptoms: Brown or reddish discoloration around seals or on the housing. Rough running and increased noise, especially right after washdown cycles.
- Root causes: Washdown spray hitting the seals directly. Aggressive cleaning chemicals. Poor drying practices. Grease film too thin to protect metal surfaces.
- Corrective actions: Upgrade sealing or add deflectors. Adjust spray patterns so they don’t aim at seal areas. Switch to a grease that stands up to your cleaning chemistry. For chronic issues, consider chromium-family or nickel-phosphorus coatings on rings and shoulders.
- What won’t solve it: Chronic misalignment, open ingress paths, or under-specified seals.
2. Grease Washout or Lubricant Starvation
- Symptoms: Grease that looks milky or has disappeared entirely. Higher operating torque. Noise that emerges after the machine has been running a while.
- Root causes: Water getting past the seals. Cleaning chemicals that break down the grease. Relubrication intervals set too far apart. Grease degraded by heat.
- Corrective actions: Review your relubrication schedule. Verify grease compatibility with both operating temperature and cleaners. Ensure seals are intact and functioning.
3. Shaft Creep – Inner-Ring Micro-Movement
- Symptoms: Fretting corrosion (reddish or black powdery residue) on the shaft under the bearing. Visible wear marks or scoring on the shaft. Overheating in the bearing area.
- Root causes: Locking force insufficient for the load. Vibration gradually backing off set screws. Shaft undersized for the bearing bore.
- Corrective actions: Switch to adapter sleeve (UK) locking for 360° clamping. Apply anti-fretting paste during installation. Tighten set screws and lock nuts to the torque values listed in the manufacturer’s specifications.
4. Abrasive Wear from Contamination
- Symptoms: Scoring or pitting on rolling elements and raceways. Increasing noise and vibration. Service life noticeably shorter than expected.
- Root causes: Dust, sand, or process fines entering through seals that have failed or were never adequate for the environment.
- Corrective actions: Upgrade to a more robust sealing configuration – add shrouds or move to labyrinth seals. Keep the installation area clean so contaminants don’t get into the bearing before it even starts running.
Common Industry Applications
Insert bearings are found throughout industrial machinery:
- Automotive – Assembly line rollers, conveyor systems, powertrain test rigs.
- Agricultural Machinery – Combine harvesters, balers, tillage equipment, sprayers.
- Material Handling & Conveyors – Belt conveyors, roller conveyors, bucket elevators.
- Food Processing – Wash-down areas requiring corrosion-resistant materials and food-grade lubricants.
- Pumps & Fans – Industrial pumps, HVAC fans, blowers.
- Mining & Aggregate – Crushers, screens, heavy-duty conveyors.
Interchangeability and Standards
Most insert bearings follow international standards (ISO, AFBMA, JIS) for external dimensions and bore sizes. This ensures that a bearing from one manufacturer can be replaced with an equivalent from another without modifying the equipment.
The UC, UK, SA, SB, UE, and UEL series designations are widely recognised and cross-referenced across brands. When ordering a replacement, match both the insert series and the housing style.
Conclusion
Insert bearings offer a versatile, cost-effective solution for shaft support across countless applications. Their key advantages – self-alignment via the spherical outer ring, pre-lubrication, standardized dimensions, and multiple locking options – make them a practical choice for engineers and maintenance professionals alike.
When selecting an insert bearing, focus on three decisions:
- Locking mechanism – set screw (UC/SA/SB) for economy and quick MRO replacement; eccentric collar (UE/UEL) for quick axial positioning; adapter sleeve (UK) for heavy-duty reliability, reversing loads, and high-speed operation
- Sealing – matched to your operating environment, from single-lip rubber up to multi-lip with metal flingers
- Shaft fit – slip-fit with h6 to h9 tolerance; ensure short bearing spacing to avoid axial displacement issues
Start with your shaft diameter and load requirements. Work through the selection framework above. You’ll find a solution that fits your machinery and your maintenance schedule.
Key Takeaways
- Insert bearings are pre-assembled, ready-to-mount units based on 62/63 series deep groove ball bearings
- Three locking mechanisms: set screw (UC/SA/SB), eccentric collar (UE/UEL), and adapter sleeve (UK) – each suited to different operating conditions
- Maximum misalignment: 5° for non-relubricatable, 2° for relubricatable bearings
- Locking torque must follow manufacturer’s technical specifications – overtightening can damage the inner ring
- Choose sealing and housing material based on your operating environment – stainless steel and H1 grease for food/washdown
- Standardized dimensions ensure global interchangeability across brands
An insert bearing – also known as a radial insert ball bearing, wide inner ring bearing, or Y-bearing – is a single-row, ready-to-fit unit based on sealed deep groove ball bearings. See Section 2 (Definition & Components) for a full technical description.
Insert bearings are based on sealed deep groove ball bearings in the 62 and 63 series.
Three primary methods: set screw locking (UC/SA/SB), eccentric collar locking (UE/UEL), and adapter sleeve locking (UK). Each offers different clamping force, shaft protection, and vibration resistance.
UC series uses set screw locking – simple and fast, suitable for moderate loads. UK series uses adapter sleeve locking – provides 360° clamping force without shaft damage, ideal for reversing loads, high vibration, and shafts without shoulders.
200 series denotes standard duty with standard load capacity. 300 series denotes heavy duty with enhanced load capacity for demanding applications with higher loads and vibration.
Both use eccentric collar locking. UE series features flat head design. UEL series features extended inner ring for enhanced shaft support.
Both use set screw locking. SA series is the standard configuration. SB series features narrow inner ring design for applications with axial space constraints.
Yes. Insert bearings are factory-filled with grease and sealed. They are ready for use upon installation and require no initial lubrication.
Yes. The spherical outer surface enables initial misalignment by tilting in the housing, compensating for shaft deflection and mounting inaccuracies. See Section 3 (Features & Advantages) for details.
Recommended shaft tolerance classes are h6 to h9. Insert bearings are designed for slip-fit mounting, not interference fits.
Insert bearings are not intended to accommodate axial displacement of the shaft relative to the housing. The distance between bearing positions should be short to avoid excessive induced axial loads from thermal expansion.
The permissible operating temperature for NBR seals is –30 to +100°C. Temperatures up to 120°C can be tolerated for brief periods.
Yes. Standardised dimensions ensure interchangeability across manufacturers. Always confirm the bore size, locking method, and series designation to ensure a direct replacement.
