Differential Material?
Differential Material?
(OP)
I am trying to get an idea of what material to use if I want to build a differential for a very small vehicle? Does anyone have recommendations? What do most automobiles have?
Blessings :)
Blessings :)





RE: Differential Material?
http://aplsweb.com/Topics/Differential.htm
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Feeling frisky.........
www.tailofthedragon.com
RE: Differential Material?
See it at:
http
Timelord
RE: Differential Material?
Seriously a good alloy steel will work great for the gears, and teh case could be aluminium or plastic. The trouble with building your own is that it is almost never cheaper.
RE: Differential Material?
Blessings
RE: Differential Material?
For maximum strength and durability, vacuum carburize the above materials and give them a real -320F cryogenic process with proper ramp down, hold and ramp up, followed by a proper tempering.
RE: Differential Material?
Thanks for giving me details. Do you have any suggestions for the carrier material. I know ductile iron could be used but I also heard that aluminum alloys work well too. I was thinking of a AA 356 sandcast or a 6061 T6?
Blessings
Drew
RE: Differential Material?
Regards
RE: Differential Material?
RE: Differential Material?
Thanks for the warning. What are your concerns with using a cast housing?
Blessings
RE: Differential Material?
RE: Differential Material?
I should have specified aluminum casting in my reply to carnage1. I think it is the "aluminum" casting that he is cautioning me against.
Blessings
RE: Differential Material?
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Differential Material?
As for cast iron it is great stuff,a bit heavy, but it never warps. (unless my grandmother has been cooking with it)
RE: Differential Material?
My only problem with extrusion is the price of material will be more and the process of machining will be quite extensive. A cast part comes already hollowed out and close to the dimensions of the finished product leaving only a little left to machine. The die will cost a fair bit but we plan an making alot of parts.
Blessings
RE: Differential Material?
RE: Differential Material?
Could you stamp a thick enough aluminum to make the rear cover out of?
RE: Differential Material?
Many people think that casting makes brittle, failure prone components. They are wrong, just tell GE or PCC that casting is not the best method to make turbine blades and they'll tell you to jump off a long dock.
The steering knuckles in most (if not all) of the production vehicles in the US are cast. They are not brittle; in fact quite the opposite.
An A356-T6 sand cast housing would be the optimum, there is geometry that can be cast in that will provide plenty of stiffining and strength. Once the patterns are made and tested the cost per pound drops spectacularly. The rear cover could easily be die cast/permanant mold cast. (at least thats how the one on my car is made) I dont know about front cover, mainly because I've never seen an automotive diff with one. (well on front axle, but then it doesn't have a "rear" cover)
Sure a highly engineered machining from billet 6061-T6 would be awesome - the costs would be through the roof. So would the swarf. (or the production efficency would be really low.)
Also welding on 6061-T6 is only possible if you are going to re-solutionize and age after welding. (otherwise the weld is going to be really soft.)
Teh cover could be fine-blanked, but if you think molds/patterns/dies for casting cost a pretty penny, you should see what a good stamping die costs!
RE: Differential Material?
aprox. how many units does it take to make casting break even?
or are there multiple types of aluminum casting with various setup costs?
can you weld annealed 6061 and then heat treat or does the entire piece need annealed again before heat treatment?
RE: Differential Material?
Commercial automotive components are more likely to be low pressure die cast. There is a slight improvement in porosity and shut lines, but if you can afford the time to remelt the failures, there is not a whole lot wrong with sandcast, as, in this case, stiffness is more important than strength. I'd say that in the case of wheels, where strength is more important, that I would be wary of sandcast parts.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Differential Material?
Blessing to you all!
RE: Differential Material?
Try here for more info on ADI:
h
google it for tons of links (including foundries that can cast it up for you)
RE: Differential Material?
I really doubt that aluminium would not be up to the job, but you would have to design it. I mean, we are engineers, right?
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Differential Material?
Yeah, I think I would like to design an aluminum differential, but I will have to see how soon my boss wants the first prototype ready. I have a few other major tasks to complete first before I can start redesigning a differential.
You guys have been a great help! I hope one day I can return the favour.
Blessings!
RE: Differential Material?
Check with Gary Vassighi at 3DCam http://www.3d-cam.com/
for help with the stereolithography pattern.
One other point is I have made housings out of welded 6061 and treated to T6 and it was a miserable twisted piese of crap. If I did it again I would jig weld it and leave plenty of room for post machining.
Also when you talk to John List he can help you with alum material that is stronger than 356 T6.
Regards
RE: Differential Material?
I worked at a place that made turbine blades and they were forged ...
That being said I wouldn't dismiss any option even forging without a cost inquery.
I once had a manager at Rocketdyne tell me that cnc was to expensive..and my point is look at evrything even forgings..
NickE will tell you that its strength is it the grain direction.
Regards
RE: Differential Material?
Thanks for the heads up. I have sent an email to John List. Hopefully he can help.
Blessings
RE: Differential Material?
RE: Differential Material?
Part geometry and material must be part of the design to be successful.
here is a production rear axle housing apparently fabbed as weldment. The diff proper is still a ferrous casting of some sort.
http
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Keeping bearing bores/seats to size in aluminum and even Stainless steel housings is a painful process, frought with unhappy compromises. British motorcycles using aluminum connecting rods with insert type bearings develop negative clearances in real cold weather. Not that I'd expect one to start or run in those circumstances.