In a nacelle, bronze is a sliding surface, not a rolling one: it is there to conform, damp and avoid welding itself to stainless under a slow oscillating load. Wind Turbines duty is very long life, oscillating pitch and yaw motion, moisture ingress; the material is what decides whether the bearing survives it.
| Industry duty | combined radial, axial and tilting-moment load over a 20-year life target |
|---|---|
| Typical media | moisture, salt air offshore, old grease |
| Housing temperature | −30 to +60 °C |
| Material and grade | cast bronze (CuSn6 / C93200) |
| Hardness | 60–80 HB |
| Temperature ceiling | 250 °C |
| Corrosion / chemical | water and seawater; needs grease or graphite plugs |
| Relative cost | ≈1.5× of a standard 52100 bearing |
Pitch and yaw bearings move through a few degrees, reverse, and then sit still for hours under load. A rolling element in that duty brinells at the contact because the lubricant film is never rebuilt. A bronze sliding surface is happier: it conforms, damps the oscillation and wears slowly, and its wear can be measured at service rather than discovered as a failure.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Yaw drive bush | Bronze bush | Bronze bush, grease | Slow oscillation under a heavy moment load. |
| Pitch bearing spacer | Bronze spacer ring | Bronze spacer ring | Carries the clamp load without brinelling the raceway. |
| Blade root bearing | Spherical plain | Bronze or PTFE lined plain bearing | Oscillating motion at very low speed. |
| Material | Fit here | Choose it when |
|---|---|---|
| Bronze | Best fit | Oscillating, heavily loaded sliding surfaces that cannot build a lubricant film. |
| POM | Workable alternative | Light, dry positions only. |
| 100Cr6 / 52100 | Workable alternative | Continuous rotation rather than oscillation. |
Because the motion is a few degrees and reverses, so the same contact point is loaded repeatedly without a film. A sliding surface or a different bearing design avoids it.
Typically every six months, and more often on sites with high turbulence. The grease is what keeps the bronze from fretting.
As a spacer or a lined plain bearing, yes. Weight and the difficulty of access are the constraints, not the material.
Hardness, temperature, corrosion and equivalents for cast bronze.
Read →Typical duty, recommended types and suffixes for wind energy.
Read →Gearbox & main shaft — gearbox planet and helical stages, main shaft and generator positions.
Read →Generator & high speed — generator bearings and high-speed stages where converter voltage and speed limit steel.
Read →Send the position, bore size, quantity and the medium it sees. We reply with the material certificate, clearance class, lubricant and price within 30 minutes on working days.