Overview
PU sleeve bearings are precision-machined plain bearings made from polyurethane (PU) elastomer, used to support rotating and oscillating shafts while absorbing shock, damping vibration, and resisting abrasion. Unlike rigid polymer or metal bushings, polyurethane combines load-bearing capacity with high elasticity, allowing it to deform under impact and recover without cracking or permanent set. This makes PU sleeve bearings ideal for equipment exposed to heavy shock loads, vibration, dust, and moisture, where quiet operation and long wear life are essential. OrroMFG produces PU sleeve bearings using precision CNC turning and polyurethane processing, delivering accurate bore dimensions, concentricity, and consistent hardness for reliable, low-noise bearing performance.
PU sleeve bearings are specified where conventional bronze or polymer bushings fail prematurely under impact or abrasive conditions. Their high tear strength and abrasion resistance outlast rubber and many thermoplastics in sliding wear, while their resilience absorbs shock and reduces noise and vibration transmitted through machine frames. Polyurethane also resists oils, greases, water, and many chemicals, and does not corrode, making these bearings suitable for wet, dusty, and outdoor environments. OrroMFG offers PU in a range of durometers, from softer 80A grades for maximum shock absorption to harder 95A grades for higher load capacity and wear resistance. Bearings are available in plain cylindrical, flanged, and shouldered designs, with grooved or pocketed bores, and can be machined or molded to customer requirements. Every bearing is produced to tight tolerances to ensure smooth shaft support, uniform load distribution, and long service life.
Key Features
- Excellent Shock Absorption: High elasticity deforms under impact and recovers, protecting shafts and housings from shock loads.
- Superior Abrasion Resistance: Outlasts rubber and many thermoplastics in sliding and abrasive wear conditions.
- Vibration and Noise Damping: Resilience absorbs vibration and reduces transmitted noise for quieter machinery operation.
- High Tear and Load Strength: Combines load-bearing capacity with toughness to resist tearing under harsh service.
- Chemical and Moisture Resistance: Resists oils, greases, water, and many chemicals without corroding or swelling significantly.
- Customizable Hardness: Durometer grades from soft to hard are selected to balance shock absorption, load capacity, and wear life.
Material Specifications
| Property | PU 80A Shore | PU 90A Shore | PU 95A Shore | Glass-Filled PU / Reinforced PU |
|---|---|---|---|---|
| Density (g/cm³) | 1.10 - 1.15 | 1.12 - 1.18 | 1.15 - 1.20 | 1.20 - 1.30 |
| Hardness (Shore A / D) | 80A | 90A | 95A | 55 - 65D |
| Tensile Strength (MPa) | 25 - 35 | 35 - 45 | 40 - 55 | 50 - 70 |
| Tear Strength (kN/m) | 45 - 60 | 60 - 80 | 70 - 95 | 80 - 110 |
| Tensile Modulus (MPa) | 15 - 25 | 25 - 40 | 40 - 65 | 80 - 140 |
| Compression Set (%, 22h) | 20 - 30 | 15 - 25 | 10 - 20 | 8 - 15 |
| Continuous Service Temp (°C) | 70 - 80 | 80 - 90 | 80 - 90 | 90 - 100 |
| Coefficient of Friction | 0.40 - 0.70 | 0.35 - 0.60 | 0.30 - 0.55 | 0.25 - 0.45 |
| Abrasion Resistance (DIN, mm³) | 35 - 55 | 25 - 40 | 20 - 35 | 15 - 25 |
| Water Absorption (24h, %) | 0.3 - 0.6 | 0.3 - 0.5 | 0.2 - 0.5 | 0.2 - 0.4 |
Applications
Material Handling
PU sleeve bearings support shafts and pivots in conveyor pulleys, rollers, and diverting mechanisms, absorbing impact from shifting loads and reducing noise in high-throughput facilities. Their abrasion resistance and quiet operation suit continuous handling of packages, parcels, and bulk materials, while their moisture resistance supports washdown and outdoor installations.
Mining & Aggregates
In mining and aggregate processing, PU sleeve bearings are used in vibrating screens, feeders, and conveyor idlers exposed to heavy shock, dust, and abrasive media. Their resilience absorbs vibratory and impact loads, and their high tear strength resists the abrasion that rapidly wears metal and rubber bushings in these severe environments.
Construction Equipment
PU sleeve bearings serve in excavators, loaders, and compactors at pivot points, linkages, and suspension elements subject to shock and contamination. Their shock absorption protects structural components, while their resistance to mud, water, and temperature variation maintains reliable operation on demanding job sites.
Industrial Machinery
In industrial machinery, PU sleeve bearings support oscillating and rotating shafts in presses, mixers, and packaging equipment where vibration damping and quiet operation are important. Their load capacity and wear resistance maintain performance in continuous duty, and their chemical resistance suits machinery exposed to oils and process fluids.
Agricultural Machinery
PU sleeve bearings are employed in harvesting, seeding, and material handling equipment, where dust, moisture, and shock loads are common. Their abrasion resistance and shock absorption extend service life in field conditions, and their corrosion resistance avoids the rust and seizure that affect metal bushings.
Operating Conditions
- Temperature Range: -30°C to +90°C (-22°F to +194°F) continuous service; performance varies with durometer and grade
- Load Capacity: Suitable for medium radial loads with high shock tolerance; harder 95A grades support higher loads and contact stress
- Speed: Best suited to low-to-moderate sliding speeds; high elasticity maintains smooth support in oscillating and slow-rotating applications
- Lubrication Compatibility: Can run dry in many applications; compatible with greases and oils where added life or cooling is desired
- Chemical Compatibility: Resistant to water, oils, greases, and many dilute chemicals; not recommended for concentrated acids, strong solvents, or hot water over extended periods
- Moisture and Humidity: Resists water and humid conditions without corroding; suitable for washdown and outdoor service
- Shock and Vibration: Excellent shock absorption and vibration damping protect shafts, housings, and machine frames
- Abrasive and Contaminated Media: High tear and abrasion resistance performs well in dusty, gritty, and contaminated environments
Material Comparison
| Material | Strength | Temp Range | Abrasion Resistance | Cost | Best For |
|---|---|---|---|---|---|
| Polyurethane (PU) | Good | -30 to +90°C | Excellent | Medium | Shock absorption, vibration damping, abrasive service |
| Rubber (NBR) | Fair | -30 to +100°C | Good | Low-Medium | General vibration isolation, flexible sealing |
| POM (Acetal) | Good | -40 to +100°C | Very Good | Medium | Precision, low-friction dry bearings |
| Nylon PA66 | Good | -40 to +120°C | Good | Low | General industrial bushings, low cost |
| Bronze (Oil-Impregnated) | High | -40 to +150°C | Very Good | Medium | High-load, lubricated industrial bearings |
Choose PU sleeve bearings when:
- Heavy shock and impact loads must be absorbed to protect shafts and housings
- Vibration and noise reduction are important for machinery or the working environment
- Abrasive, dusty, or gritty conditions cause rapid wear of other bearing materials
- Moisture, washdown, or outdoor exposure requires corrosion-free bearing support
- Low-to-moderate speed operation with medium radial loads applies
- Custom hardness is needed to balance shock absorption, load capacity, and wear life
Customization Options
- Material Grades: Polyurethane in 80A, 90A, and 95A Shore hardness, glass-filled/reinforced PU, oil-resistant PU, and hydrolysis-resistant PU
- Bearing Types: Plain cylindrical, flanged, shouldered, and split (slotted) sleeve bearings
- Size Range: Bore diameters from 5 mm to 250 mm; custom sizes and wall thicknesses available
- Bore Configurations: Plain, grooved, and pocketed bores for lubrication retention or debris management
- Flange and Shoulder Designs: Custom flange diameters, thicknesses, and shoulder geometry for axial location
- Tolerance Grades: Machined to IT7-IT9 bore tolerances with controlled concentricity and wall thickness
- Surface Finishing: Fine-machined, buffed, and chamfered edges for smooth shaft engagement and reduced wear
- Bonding and Inserts: Bonded metal or polymer inserts and reinforced cores for higher load capacity
- Color Options: Natural amber, black, and custom colors for identification
- Secondary Operations: Press-fit sizing, assembly with housings and shafts, and clearance matching to customer shafts
Quality Assurance
OrroMFG is committed to delivering PU sleeve bearings of consistent quality and reliability. Our ISO 9001:2015 certified manufacturing facilities combine precision CNC machining with controlled polyurethane processing to produce bearings that meet demanding dimensional and performance requirements. Careful material handling and process control maintain consistent hardness and properties throughout production.
Quality control begins with incoming verification of polyurethane grade, durometer, and certification against material data sheets. In-process inspection includes dimensional checks with coordinate measuring machines (CMM), bore and outside-diameter measurement, concentricity and wall-thickness checks, and durometer verification to confirm hardness consistency. For high-load and high-shock applications, we perform functional load, wear, and compression-set testing to validate performance under simulated operating conditions. All finished bearings undergo final inspection of critical features, with sampling for wear testing where required. Products are supplied with material certificates (COA), dimensional inspection reports, and full batch traceability, and first article inspection (FAI) reports are available for new or critical parts.
