Tribology of a Driveline Material

[MolaKule]

The following minimum requirements for this material might include: 1. Dynamic and static coefficients of friction higher than 0.2 in engagement. 2. Preferably higher dynamic coefficient of friction than static coefficient of friction. 3. Chemical resistance to fluids. 4. Wide operating ranges for temperature, pressure and speed with a range of power density of 0.5 to 6 watts/mm2. 5. The thickness range between 0.5 mm to 1 mm. What might this important material be? Guidelines for the Question of the Day: 1. No Piston Cup Lapel Pin will be awarded to the same person within 14 days of a previous award. 2. Please respond with a complete sentence. 3. Please do not post links. If a question arises as to the need for clarification, then sources and links may be requested. 4. Please, no off topic posts.

 

[LargeCarManX2]

It would be grease, one of the most important materials needed for driveline life?

 

[29662]

I think I know what it is, but since I'm not eligible to win again for two weeks I'll defer to someone else. Mola, just found out about the question of the day. I'm finding it rather enjoyable. Makes for some interesting reading during downtime at work...

 

[MolaKule]

Hey, thanks. I hope we can keep it interesting for you guys.

 

[bepperb]

Might it be Kevlar?

 

[MolaKule]

Originally Posted By: bepperb

Might it be Kevlar?

Kevlar fibers could be included in this porous material.

 

[IndyIan]

Drive clutch material? The thickness is throwing me off. 1mm seemed about what my dirt bike had on the multiplate wet clutch. I assume a dry car clutch has more. 6W per mm^2 is a lot of heat too! I have another guess but I'll go with clutch as my final answer.

 

[ironman_gq]

fiber plates in the clutch pack of an automatic transmission

 

[djb]

That sounds like a friction disk in a clutch-style LSD. They are designed to slip a bit rather than grab, thus the requirement for a higher dynamic coefficient of friction. They need to operate when cold -- first start of an icy day -- through very hot after long highway runs.

 

[Rand]

carbon?

 

[MolaKule]

Originally Posted By: Rand

carbon?

Carbon fibers could also be included in this porous material.

 

[quint]

Brake pad linings?

 

[MolaKule]

The clutch disc material of Automatic Transmissions, and other wet clutch applications, are made of porous friction materials which are bonded to steel core plates. Friction materials may include cellulose, carbon fiber, Aramids, fiberglass, or a combination of materials (composites). Today, composites rule. Note: Sintered metal composites may be found in HDD applications. This material must exhibit: 1.) Mu(o), low speed dynamic coefficient; affected by friction material ingredients and ATF additives adsorption 2.) Mu(i), initial dynamic coefficient at high speed; affected by hydrodynamic effects/porosity/compression/roughness. Both ironman_gq and Indylan now share and can proudly claim the extinguished Piston Cup Lapel Pin .