Clutch plate friction materials
Clutch plate friction materials
(OP)
We are considering development of a new multi-plate wet clutch pack and curious what friction materials might be available to increase friction over an OEM type friction material? We will have the increase the power holding ability by 3x in this clutch. We cannot increase the diameter of the plate though. We can possibly decrease thickness to add more plates in the stack as well as decrease the ID to increase the friction surface area and will of course, raise the spring rates.





RE: Clutch plate friction materials
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Clutch plate friction materials
RE: Clutch plate friction materials
Can you take a tip from tire technology and think about removing the lubricant from the interface?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Clutch plate friction materials
I thought some carbon fiber or kevlar products had better friction but I guess if I knew, I would not be asking.
RE: Clutch plate friction materials
RE: Clutch plate friction materials
Mike Halloran
Pembroke Pines, FL, USA
RE: Clutch plate friction materials
The friction materials used in production AT clutch packs are designed to give consistent and smooth friction characteristics over the life of the transmission, as opposed to maximum grip. The OEM transmission designers are mostly concerned about shift quality. The materials used in wet clutch facings are usually classified as "papers".
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You need to be careful about putting more power through a wet clutch pack than it was designed for. The increased heat generated in the clutch plates during higher power shift events must be either absorbed or dissipated somehow. So unless you improve the heat conduction path away from the clutch facings or increase the effective thermal mass of the clutch pack, then you will likely exceed the flash/oxidation point of the transmission fluid and cause it to fail. Wet clutch power capacities are limited by the fluid properties, and not by the facing material properties.
Since wet clutch power capacity during shifts is primarily limited by the heat generated from slippage, making the plates thinner and increasing their number probably won't have much effect. Neither will increasing the axial clamping force on the plate stack. Increasing the number of plates/stators and increasing the axial clamp force will, however, increase the amount of torque the clutch pack can transmit without slipping, for what it's worth.
Good luck.
Terry