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 Post subject: Planetary Gear System
 Post Posted: Fri May 18, 2012 10:42 am 
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Joined: Tue May 15, 2012 5:44 pm
Posts: 9
Hey,
Can anyone who have researched on how best the speed coupling or the torque coupling suits a parallel hybrid race car , tell me the details????
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 Post subject: Re: Planetary Gear System
 Post Posted: Fri May 18, 2012 4:44 pm 
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Joined: Thu Sep 09, 2010 6:32 pm
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Location: University of Idaho
Could you please be a bit more specific as to what it is you would like to know.


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 Post subject: Re: Planetary Gear System
 Post Posted: Fri May 18, 2012 11:36 pm 
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Joined: Tue May 15, 2012 5:44 pm
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wos9722 wrote:
Could you please be a bit more specific as to what it is you would like to know.



Since the race cars performance depends upon the acceleration , which type of coupling would suit the design of the car so that the powers get added up & also it doesn't affect the acceleration???
And it would be helpful if you can provide a detailed info on Planetary Gear System...


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 Post subject: Re: Planetary Gear System
 Post Posted: Mon May 21, 2012 9:54 pm 
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Joined: Thu Sep 09, 2010 6:32 pm
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Location: University of Idaho
Sadly I can't give you a strait answer to your question because the speed vs. torque argument really depends on where you are planning on coupling the electric motor and what type of electric motor you are planning on using along with the voltage/amperage that is going to be supplied to it. My suggestion would be to work up a rough model of your vehicles acceleration and from there you will need to make some calls on what it is you want to accomplish; is it a first place acceleration run or just make it by in under 10 seconds?

Also, rather than try and describe a planetary geartrain to you here, I did a quick Google search found this and I thought it was a good description to start off with. http://www.youtube.com/watch?v=UakeTEJlXGw Our team uses a planetary gear system for a final reduction before our differential to save space but my guess is you may be thinking of using the planetary for other purposes than a simple gear reduction. Such as the Prius drivetrain and if that is the case I wish you good luck because that would be no small undertaking. Let me know if this helps or if you have any other questions.


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 Post subject: Re: Planetary Gear System
 Post Posted: Thu Jun 28, 2012 5:24 am 
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wos9722 wrote:
Our team uses a planetary gear system for a final reduction before our differential to save space but my guess is you may be thinking of using the planetary for other purposes than a simple gear reduction.

So can you be more specific about how you exploit planetary gear system ??
So are you using another gear box to control the speed???


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 Post subject: Re: Planetary Gear System
 Post Posted: Fri Jun 29, 2012 11:51 am 
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Joined: Mon Mar 12, 2012 7:07 am
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kishor5466 wrote:
wos9722 wrote:
Our team uses a planetary gear system for a final reduction before our differential to save space but my guess is you may be thinking of using the planetary for other purposes than a simple gear reduction.

So can you be more specific about how you exploit planetary gear system ??
So are you using another gear box to control the speed???


I believe he means that the planetary is used for the final reduction between the transmission and the differential. If you look at FSAE cars the most common method of achieving this reduction between the output shaft of the engine and the differential is with a large sprocket connected to the differential. Using a planetary probably saves a lot of space, although I am betting it is a bit heavier than a simple sprocket.


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 Post subject: Re: Planetary Gear System
 Post Posted: Mon Jul 02, 2012 10:03 pm 
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Joined: Thu Sep 09, 2010 6:32 pm
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Location: University of Idaho
This is absolutely correct, the University of Idaho uses a planetary gear reduction rather than a rear sprocket to reduce the required packaging space/hardware that would be required via a sprocket. There is a weight gain of about 10lbs after the mounting/housing/etc. is accounted for but the tighter packaged drivetrain is well worth it. The gear reduction works as such, we hold the ring gear stationary, drive the sun gear from our parallel hybrid powertrain, and the plaint gears are attached to our differential driving our rear axles. My bet again is that you are looking to build some sort of power-split hybrid powertrain and are looking for the best way to control such a device. If this is the case I would highly suggest going onto SAE and looking up some papers on the subject they have a bunch that directly relate to the architecture and control of such a powertrain. Or you could do what we did, go find a junked Prius drivetrain and reverse engineer it...(spoiler alert! U of I's future powertrain design)


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 Post subject: Re: Planetary Gear System
 Post Posted: Thu Jul 05, 2012 3:15 am 
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Joined: Mon Mar 12, 2012 7:07 am
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Doing a power split design similar to a Prius drive-train would be very complex. Generally planetary systems are used for reductions such as what Idaho is doing, not as the transmission from the crank. I would be very interested to see a car that used a planetary system with an electric motor that removed the stock transmission from a motorcycle engine.


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 Post subject: Re: Planetary Gear System
 Post Posted: Wed Jul 25, 2012 5:02 pm 
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Joined: Thu Sep 09, 2010 6:32 pm
Posts: 68
Location: University of Idaho
With that, to any teams looking into a power-split device don't take the control of such a device lightly. The mechanical portion of such a device is simple in comparison to the control. The control scheme is the biggest hurdle we have had to face so far for our future powertrain design but we are also lacking in EE support so perhaps teams with EE's might say otherwise.


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