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Cone Clutch Interface Surface Treatments

I am designing a cone style friction clutch, and am looking for some advice for how to properly surface treat/coat the two surfaces of the clutch to attain a relatively similar coefficient of friction (.08-.107) to that of grease used between steel and aluminum.

The clutch is to see relative high torque ( 2000-4000 in-lb ), low speed ( 2rpm ), and the two parts of the clutch are 1018 steel, and 6061-T6 aluminum.

I would like to have a more permanent solution like a surface coat or finish, that is dry, and has good wear resistance. And yet can facilitate torque transfer.

Any help would be much appreciated. Thanks!

Ravi Singaraju
Product Designer - Loveland, Colorado, USA
January 16, 2008

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Ravi,

you're trying to achieve a very low coefficient of friction for a dry interface. The only thing that comes to mind is to hard anodize the aluminum and PTFE impregnate the coating. There are many suppliers that can do that for you. Since steel is so much harder than the aluminum substrate and the coating is so thin make sure that the edges of the steel part never contact the aluminum wear surface otherwise you can dent the aluminum. In other words, the steel surface should be uninterrupted and should be bigger than the aluminum surface. That MIGHT work for you.

Ilya Lisenker
- Dayton, Ohio, USA
February 26, 2008