Jeff,
Here's a link to the HPI 3 speed transmission. I understand that you would
prefer using an off-the-shelf tranny, but I thought that you might like the
"r/c" transmission link. It was just a little food for thought. :)
http://www.hpiracing.com/coolstuff/product_features/3speed_tranny.htm
http://www.trossenrobotics.com/images/productdownloads/011201_emaxx_tranny_assy.pdf
http://auto.howstuffworks.com/transmission.htm - See the 2-speed diagram in
the middle of the page.
-Charley
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Today's Topics:
1. Re: Motorcycle transmission-motor interfacing (Jeff)
2. Re: Motorcycle transmission-motor interfacing (Jeff)
3. Re: ListServ Digest, Vol 15, Issue 1 (Jeff)
4. Some motorcycle How-tos (lyle sloan)
----------------------------------------------------------------------
Message: 1
Date: Sun, 10 Dec 2006 00:24:39 -0600
From: Jeff
Subject: Re: [ElectricMotorcycles] Motorcycle transmission-motor
interfacing
To: ElectricMotorcycles
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=us-ascii; format=flowed
Kevin,
Thanks for the info on sources of self-contained transmissions. I would
think that would be the ideal for my situation, but it doesn't totally
preclude the others. Compact size is my primary concern, followed
closely by the ability to have a wide-range-reduction gear set. I'd
personally prefer to design for splines than keyways. Keyways always
seem to acquire slop and ruin the driveshaft and anything it's connected
to (at least on a wheelchair).
Self-contained would certainly make for easier maintenance.
I had some questions (everyone here will either roll their eyes, or
groan) about the general size and weight of transmissions. I know from
your links and from other stuff I've found on the net that this is all
hugely variable, but are we talking (on weight):
10-30 pounds?
20-50?
40-80?
It would be great if I could find out what sort of ballpark we're
talking about.
Can you ballpark on the sizes, too?
It really is a major production for me to get to any sort of bike shop
-- or anywhere for that matter. If I could find a place on the net that
had some of this info, it'd be great.
Jeff
Ok, I just found an interesting site:
Dan's Motorcycle Repair & Engine Repair Information Guide
DAN'S ONLINE MOTORCYCLE REPAIR COURSE
http://www.dansmc.com/MC_repaircourse.htm
Dan's Motorcycle "Shop Manuals"
http://www.dansmc.com/shopmanual1.htm
Kevin Caldwell wrote on 12/01/06 21:17:
> There are a few other sources of separate, self-contained motorcycle
> transmissions than Harleys. All the '60s and '70s Nortons, Triumphs,
> and BSA's had separate 4 speed transmissions. The clutches sat on the
> transmission main shaft, and were driven by a 3 row chain off the
> engine around the outside of the clutch. They are reasonably small.
> They might be getting to be parts for collector's bikes at this point
> though. Still might be worth a look at a wrecker or eBay
>
> BMW airheads had separate transmissions into the late '80s at least,
> and they are 5 speeds, but they are set up for shaft out, and a
> spline drive in.
>
> There are a few on eBay right now:
> Or you might find one at:
>
> http://www.ibmwr.org/market/adlist.php?cat=aps
>
> The self-contained ones would be simpler to use. All the Japanese
> "unit" bike transmissions are so built-in to the engine, and are
> usually gear driven, it would be a bit messy to seal them off to use
> separately. Not impossible though. They usually just run with the
> engine oil, whereas the separate ones all use 50W - 90 (or something)
> gear oil which is quite a bit thicker, especially at cold temps. With
> your loads, they'd be fine with 10W - 30 engine oil though.
>
> Kevin Caldwell Courtenay, BC, Canada
------------------------------
Message: 2
Date: Sun, 10 Dec 2006 00:25:17 -0600
From: Jeff
Subject: Re: [ElectricMotorcycles] Motorcycle transmission-motor
interfacing
To: ElectricMotorcycles
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=windows-1252; format=flowed
Jesse Haubrich wrote on 12/01/06 23:44:
>> 0-6mph 0-4.5mph 0-3 or 3.5mph 0-2.5mph (would be nice) 0-1.25 or
>> 1.5mph
> Jeff, you honestly don't need a transmission to utilize the full
> torque of your electric motor. Especially if you keep it at these
> speeds. We're accustom to the torque of a combustion engine which
> peaks in short bands, but an electric motor's torque is, for the most
> part, constant.
If you're talking about an AC motor. I'll be using a PM motor.
> This is one of the great things about an EV. I think you should look
> at a fixed gear setup and spend the transmission money on a higher
> output motor.
My present chair is a TEFTEC (www.teftec.com), the ruggedest chair I've
ever come across. It also the highest capacity controller of any I've
heard of (120 amp for the drive motor -- I don't remember about the
motor that steers it). I think this rating is only good for a couple of
minutes. So-called "normal" chairs have a 50 amp limit, with the
"active-use" ones at 70 amps, with an occasional one rated at 100 amp
peak. I?m not sure what the continous rating is, but it's much less. A
standard chair will have its warranty invalidated merely by pushing
around a little push mower.
At any rate, with the currents being drawn from the batteries by modern
chairs' speed and performance demands, the distance they are capable of
is starting to drop. Lots of people have noticed that if they drive at a
slower speed, the range can be extended by a fair amount -- important
when you would otherwise be stranded in your chair someplace (with no
cabs that can pick you up, and you can't walk somewhere to get help).
Being able to operate at the right gearing for the load would let the
motor operate at a more efficient power point, so this is one reason
(besides the need torque) I am considering a motorcycle transmission.
The TEFTEC can be ordered with a factory pin hitch good for towing up to
1,000 lbs on gentle slopes IF you get it geared for it. On this chair
(one of two that I'm aware of), you can swap out 2 pulleys and a toothed
belt to change your gearing. This chair of mine weighs 511 pounds. The
options for a 650 lb person would increase it (they have heavier seat
frames, suspension components, anti-sway bars, etc.), and the gearing
for that would be about 3 mph to avoid overheating the controller and
the motor. The trouble is, the gearing is predicated upon the steepest
stuff you intend to handle. It makes no allowance for all the time you
spend on level ground, not needing to be geared that low. I weigh around
200, and my chair is geared for 5 mph. Technically, I should have asked
for 4 mph. Five's just fine for most stuff, but I can tell I am
overloading things on steep driveways. That's without pulling a 300
pound trailer, which I want to be able to do for grocery store and
hardware store shopping trips. On level ground pulling 300 pounds, 4 mph
would work wiell, but up a steep hill (30-35 degrees, not percent
grade), considerable more torque is required. Many an EVer has resorted
to a gearbox in their vehicle to make it up that long uphill grade home,
especially when the state of charge is flagging at the end of the day.
> I went looking for a graph to illustrate what I'm talking about, but
> the only graph I remember seeing that makes this comparison is on the
> Tesla Motor's site. Notice how the red line is flat and starts to
> taper of at high rpm. This is characteristic of an electric motor.
> http://www.teslamotors.com/performance/performance.php
That's a characteristic of a style of AC motor, but not PM.
> In fact, if I remember correctly, the Tesla Roadster above only has
> two gears. One for in town and one for on the highway.
Correct. And it has that gearbox for a specific reason. Torque. It needs
to match the torque demanded with what the battery/controller/motor
combination is capable of supplying.
High currents cut down on efficiency, so they are extending range as well.
> Can someone please point us to a more relevant graph. I know I've see
> torque graphs on small electric motor sites specific to the motor
> for sale.
>
> Another advantage of not using a transmission is reduced complexity
> and weight!
>
> Jesse
True -- which is the reason some chairs have dumped the gearbox
entirely, and incorporated a gearless, brushless drive system. They have
a pair of monster slow-speed brushless motors that have the drive wheels
attached directly to the motor shaft. They have had problems with these
systems (electronics and bearings) for years, but I think they have been
largely worked out. "Problems" generally means a wheel falling off, or
the system not driving the motor correctly -- causing you to not go at
all, or go careening out of control through a crowd or door or wall...
stuff like that. At any rate, one of the problems they had for quite a
while was a lack of torque. It simply wasn't sufficient to get up curbs,
or door sills, or up hills, etc. If you were a heavy person, you had to
go with the standard worm drive/4-pole motor setup. That's the only
package that would supply enough torque to handle the load. Brushless
motors to handle the extra weight simply won't fit into the required
space. This same situation still exists.
Jeff
------------------------------
Message: 3
Date: Sun, 10 Dec 2006 00:26:13 -0600
From: Jeff
Subject: Re: [ElectricMotorcycles] ListServ Digest, Vol 15, Issue 1
To: ElectricMotorcycles
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=us-ascii; format=flowed
I must admit I'm still trying to figure out how this one works, but I'll
get it figured out.
I went to the site, but I couldn't find any of the three-speed stuff.
Can you point me at that, too? Three speeds would be tolerable, and it
is in the realm of possiblity for being doable, though I'd much rather
adapt something that's off-the-shelf. :-)
Jeff
Charley Snyder wrote on 12/02/06 06:45:
> Maybe this is out of the realm of possibilities for you, but why not
> try something like this for your transmission? It would have to be
> custom made for your application, but it is not too complex. A lot of
> the basic design work is complete, all you would have to do is scale
> it up for your application. There is also a 3-speed version. If I
> were to use a design like this, I would also consider using a manual
> shifting lever instead of the spring based clutch.
>
> http://www.hpiracing.com/graphics/instr/a297.pdf
>
> -Charley
------------------------------
Message: 4
Date: Sun, 10 Dec 2006 04:43:06 -0800 (PST)
From: lyle sloan
Subject: [ElectricMotorcycles] Some motorcycle How-tos
To: "EM.net"
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=iso-8859-1
Here are some .pdf of some motorcycle maintenance like
adjusting the shocks, wheel alignment, adjusting and
lubing a chain, cutting down the seat, changing brake
pads, polishing the frame, headlight aiming, and
....burnouts.
http://www.uponone.com/howtos.php
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End of ListServ Digest, Vol 15, Issue 8
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