Polymer composite bushings are self-lubricating bearings used where low friction, compact wall thickness, and reduced maintenance are more important than the heavy machined section of cast bronze. Common designs use a steel backing, sintered bronze interlayer, and PTFE-based sliding surface.
They are widely specified for dry-running or marginally lubricated service in automotive, hydraulic, packaging, textile, agricultural, and light industrial equipment.
| Quick spec | Catalog reference |
|---|---|
| Bearing type | PTFE-lined or polymer composite sleeve / flanged bushing |
| Common structure | Steel backing, bronze interlayer, PTFE fiber sliding layer |
| Friction reference | Low coefficient of friction, often listed around 0.03-0.20 |
| Temperature references | PTFE-lined products are often listed from about -319°F to +518°F |
| Motion types | Rotary, oscillating, and linear sliding |
| Size format | ID x OD x Length, or catalog part number |
Manufacturing & Performance
Composite bushings are usually formed from layered strip rather than machined from solid bronze. The steel shell gives press-fit strength, the bronze interlayer helps bonding and heat transfer, and the polymer sliding layer creates a transfer film on the shaft.
These bearings are sensitive to shaft finish, housing fit, alignment, and edge loading. They perform best when the shaft and housing are designed around the thin-wall bushing system rather than treated like a thick cast bronze sleeve.
Standard Tolerances
Composite bushing tolerances are product-series specific. Use catalog values or the drawing supplied by the manufacturer. The table below gives the practical inspection points that matter most.
| Feature | Buying note | Why it matters |
|---|---|---|
| Housing bore | Must match press-fit recommendation | Controls installed ID |
| Shaft diameter | Must match running clearance | Too tight can damage the liner |
| Installed ID | Inspect after press fit when critical | Thin-wall bearings close in after installation |
| Wall thickness | Series-specific | Affects load capacity and heat transfer |
| Edge chamfer | Required for installation | Protects the PTFE liner |
Size & Availability
Composite bushings are available in inch and metric sleeve, flanged, thrust washer, and strip forms. Standard catalog sizes are common, and custom formed parts can be quoted when volume justifies tooling or process setup.
Alternative Materials
- PTFE-lined steel-backed composite bushings for dry-running and low-friction service.
- POM-lined composite bushings for grease-lubricated applications with better contamination tolerance.
- SAE 841 Sintered Bronze when an oil-impregnated porous bronze bearing is preferred.
- C93200 SAE 660 Bearing Bronze when a machined cast bronze bearing is required.
Typical Applications
- Automotive hinges, pedals, steering columns, and suspension linkages.
- Hydraulic cylinders, pumps, valves, and actuators.
- Packaging, textile, printing, food processing, and agricultural equipment.
- Lightweight assemblies where grease fittings are undesirable.
RFQ Details That Speed Up Quoting
Send ID, OD, length, flange dimensions if needed, shaft material, shaft finish, housing material, load, speed, temperature, lubrication condition, and annual quantity.