transmission design

[Shahid]

I m curreently in fsae team in trany department.I want to design an efficient transmission system for my car,plz can any 1 help me how to initiate my design and proceed.

[ZAMR]

In case you're not trolling...

Teams usually go with the transmission that's INSIDE the engine they use.

However, you may find the occasional CVT car or custom tranny car (Western Washington is the only one I know).

Sounds like you are a first year team. Go with the stock transmission. It's about as simple as you can get.

Also, you are about to get a WHOLE lot of sarcastic answers from every 1

[t21jj]

Originally posted by Shahid:
I m curreently in fsae team in trany department.I want to design an efficient transmission system for my car,plz can any 1 help me how to initiate my design and proceed.

This is not the way to make your first post here. Please read the Teams from India thread first. If you don't know how to do your project I'd suggest that you stick to an engine that has a built in transmission as many fsae engines have. We will not teach you the basics.

[Pennyman]

I guess I'll start the absurdity...

You should totally build a transmission! Make it a transaxle and incorporate a differential inside the case. You could even use the gears from the stock tranny and machine/cast a case from scratch to house them. all you would need to do is...

-Figure out final drive and gearing kinematics
-calculate gear force and bending stress
-calculate gear surface fatigue
-design gears based on above information
-find and machine material strong enough for the application
-calculate the bending stress on your gear shafts
-find and machine shafts/splines for those shafts
-calculate the fatigue on the gear shafts
-calculate the radial/thrust loads on the bearings
-select bearings based on said loads
-select seals based on said bearings
-design a gear case based on gear, shaft, and bearing size
-find enough material to make a case and then machine it
-package everything and test it sufficiently before competition and hope it doesn't break.

[The_Man]

http://fsae.com/groupee_common/emoticons/icon_frown.gif

[MalcolmG]

Originally posted by Pennyman:
I guess I'll start the absurdity...

You should totally build a transmission! Make it a transaxle and incorporate a differential inside the case. You could even use the gears from the stock tranny and machine/cast a case from scratch to house them. all you would need to do is...

-Figure out final drive and gearing kinematics
-calculate gear force and bending stress
-calculate gear surface fatigue
-design gears based on above information
-find and machine material strong enough for the application
-calculate the bending stress on your gear shafts
-find and machine shafts/splines for those shafts
-calculate the fatigue on the gear shafts
-calculate the radial/thrust loads on the bearings
-select bearings based on said loads
-select seals based on said bearings
-design a gear case based on gear, shaft, and bearing size
-find enough material to make a case and then machine it
-package everything and test it sufficiently before competition and hope it doesn't break.

Although I realise this thread is a waste of space, and you're trying to make a statement, I think you need to realise that making a transaxle isn't as hard as you're suggesting it is. If you use a lot of stock parts then you can, to a certain extent, assume they're sufficiently strong (i.e. gears, shafts, bearings). Then it mostly comes down to an exercise in packaging and getting it made early and tested so that you can find out if any of your assumptions are incorrect. We started our transaxle design around this time last year and by April had it ready for testing.

We had no component breakages within the transaxle, with the exception of bolts coming off the crown gear on the diff because they weren't properly tightened. The biggest issue with it was oil leakage, due to the way we chose to manufacture it. Hopefully when we get the car back from Aus we can test our carbon-fibre cased transaxle, which will hopefully solve a lot of the oil leaking issues.

If you go through life thinking everything is too hard, you'll never get to do anything fun :P

[jrickert]

I wonder if most of these sorts of posts are by a single person who thinks its funny to register multiple times and ask idiot questions to stir up trouble.

[RollingCamel]

This is quite ridiculous. Though i'm new to FSAE but the rate of stupid questions is skyrocketing lately.

[Pico]

I agree completely. I don't post much at all but I think that I need to voice my disappointment.
People working on these projects spend days/months/years trying to fully understand even the basics of how things work. Countless hours designing and building. If you're now starting, do RESEARCH on your topics. I'm not going to give help to a team that doesn't help itself.
No one here is going to design it for you nor spoon feed you information. Do like all of us and put in the hard work!

Merry Christmas to everyone

[Huskie Motorsports TD]

I have been in FSAE for 7 years, I have always been able to find answers with out asking handitarded questions on this forum, in fact I think this is my 4th post maybe. The library, professors and the world wide web should have the answers you need or at least point you in the right direction. I am a M. Sc. student now in Civil Engineering and I can still find the information I need for my questions. People are not automatically experts, they research, read, interpret, and become educated.

If I have insulted anyone that is not my intent. I think rather than asking how do I start designing a transmission, you should ask how do I start designing anything. You need to decide what are your goals, constraints, and criteria. If you are constrained to an engine that doesn't have a built in transmission, the you have to design or out source one. If your engine has a built in transmission (like most motorcycle engines) then designing a separate transmission would be a gross miss allocation of resources (IMO, I am also separating snowmobile type transmission in to there own area). So before you go crazy and do what Pennyman has suggested, evaluate the feasibility of the design alternatives and then go from there. Proper engineering isn't just the design and construction, it is also the systematic evaluation of alternatives and the consideration of all relevant factors related to the design, not just the forces, materials and speed of components. Also you are talking about a transmission not the differential? Before you post make sure that you are actually posting about the right thing.

[The_Man]

This forum has been a very good resource for FSAErs all around the world. The quality of the participants and the discussions are very high and is very different from any other forum that I have come across. It has been a joy to read, and sincerely I hope someday I can sincerely significantly contribute to the forum.

That is many reasons for us to do something about the current situation here. I can already see signs of dwindling moral to post here because of a increased frequency of "stupid" questions. May be a having a separate section for beginners can help. I am really not a believer in segregation but clearly a way needs to be found where the interests of the beginners as well as the regulars(for lack of another word) are protected. Any other ideas?

[Zac]

Originally posted by The_Man:
This forum has been a very good resource for FSAErs all around the world. The quality of the participants and the discussions are very high and is very different from any other forum that I have come across. It has been a joy to read, and sincerely I hope someday I can sincerely significantly contribute to the forum.

That is many reasons for us to do something about the current situation here. I can already see signs of dwindling moral to post here because of a increased frequency of "stupid" questions. May be a having a separate section for beginners can help. I am really not a believer in segregation but clearly a way needs to be found where the interests of the beginners as well as the regulars(for lack of another word) are protected. Any other ideas?

I don't know that a beginners section is really needed. There's already a basic "rules" thread stickied to the top of the forum that seems to go largely ignored.

Maybe some type of test or quiz on basic etiquette or even just a probationary period should be put in place before a new poster can start threads?

Personally I really don't mind the random posts that much, but I would like to know what the cultural differences causing them are.

[jrickert]

I'm pretty sure that all these posts are fake. They are probably posted by some ass trying to stir up trouble. I find it hard to believe that anybody in an engineering program anywhere would be stupid enough to ask these sorts of questions.

[Shashi]

Frankly, this is pissing off. After reading that very long post about Indian teams and posting on it,people find it amusing to post stuff like this. I too get the feeling that this is a fake profiler try to cause trouble. How about making it compulsory to declare you team name and location. A fake profiler would have a hard time searching for a team whose members are not visitors to this forum.

Or even express spamster recognition wherein the fake profiler is banned by the admin after he receives x number of hits(?). I hope all here would agree it would be a much better solution to hit "Spam Alert" rather than "Rate it"! http://fsae.com/groupee_common/emoticons/icon_smile.gif