PA66 is the cheapest way to put a bearing in a stamped frame: it is tough, tolerates misalignment and costs cents moulded. Fans, Blowers & HVAC duty is light load, condensation during shutdown and noise limits; the material is what decides whether the bearing survives it.
| Industry duty | light load from unbalance and belt pull, a few hundred to 3,000 rpm |
|---|---|
| Typical media | dust, lint, condensate, pool and food washdown |
| Housing temperature | −20 to +80 °C |
| Material and grade | PA66 nylon |
| Hardness | — (polymer, 75 Shore D) |
| Temperature ceiling | 105 °C |
| Corrosion / chemical | oils and greases; swells in water |
| Relative cost | 0.15× a steel bearing of a standard 52100 bearing |
Volume air-handling products are built from folded galvanised steel, and the alignment between two such parts is measured in millimetres, not microns. A ball bearing would fight that misalignment; a nylon bush absorbs it, is quiet, needs no lubricant and can be snapped in without a press. The engineering work is all in the clearance and the moisture allowance.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Louvre / damper pivot | PA66 bush | PA66 bush, 30% glass filled | Glass fill cuts creep and wear; the bush snaps into the frame. |
| Fan hub, low speed | PA66 bush | PA66 bush with graphite | Dry running at low PV; graphite lowers the friction coefficient. |
| Filter frame slide | PA66 slide strip | PA66 strip or bush | Wear resistance against a galvanised rail with no lubrication. |
| Material | Fit here | Choose it when |
|---|---|---|
| PA66 | Best fit | Moulded pivots and bushes at low load, where cost per unit dominates. |
| POM | Workable alternative | Dimensional stability matters more than toughness — POM picks up a tenth of the moisture. |
| Bronze | Workable alternative | Air stream above 105 °C, where nylon softens. |
Two reasons: creep under the press fit, and moisture growth changing the interference. Both are designed out with a shoulder or a snap feature rather than a tighter press.
With a UV stabiliser, yes. Without one, sunlight degrades the surface within two years.
Around 300–500 N at low speed for a glass-filled grade. Above that, use POM or a bronze bush.
Hardness, temperature, corrosion and equivalents for PA66 nylon.
Read →Typical duty, recommended types and suffixes for fans & hvac.
Read →Standard fan duty — fan and blower shafts in air handling units, cooling towers and roof extract fans.
Read →Coastal & pool plant — roof extract fans, cooling tower fans and pool plant blowers in salt or chlorinated air.
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.