[ausev] Hub motors

[Clendon Gibson]

Could this not be addressed by not using all the Torque an electric motor has available? Unless you are building a drag bike do you really need so much torque you can bend the frame?

Either get a smaller sized electric motor or limit the max current you apply to the motors you do get? 

Of course I am a newb and may be talking out of my hat.

----- Original Message ----
From: MLAB <mlibrik at att.net>
To: AustinEV News Announcements and General Discussion <ausev at austinev.org>
Sent: Tuesday, April 22, 2008 2:21:13 PM
Subject: Re: [ausev] Hub motors

I had posted a similar inquiry some time ago.  One problem with hub 
motors that was pointed out to me then involved torque by the motor on 
its mountings.

On a bicycle, the frame (or fork) extends to the axle so the motor can 
typically lever against the dropouts on the fork (front wheel mount) or 
the rear dropout plates.  Chinese hub motors use oversized axles that 
are flatted to fit into the dropouts so the axle cannot rotate within 
the slot.  German Heinzmanns (or "whiny Heineys" as I call the ones on 
the rear wheels of my HPM Tri-Hauler) use torque arms like you'd see on 
a bicycle drum brake, bolted to the frame 6 inches or so from the dropouts.

On a conversion automobile, the chassis is reinforced around the engine 
mounts, so that is the only place strong enough to bolt down the motor 
without it just breaking loose and spinning in place.

A compromise solution would involve multiple motors mounted on the 
centerline of the chassis, each driving an individual wheel like a hub 
motor does (also allowing for suspension of the wheels), but even this 
would require a custom chassis or serious customization of a conversion 
chassis.  Putting a single, big motor where the engine usually lives 
saves all that trouble, apparently.

-- 
Mike Librik, LCI #929
Easy Street Recumbents
Austin, TX
(512) 453-0438
www.easystreetrecumbents.com
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