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Chain drives
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Glen
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Chain drives

im looking at using a pretty funky chain drive system on incoming this time round to really push myself to build something new, so i would just like to ask a few questions.

1) how would i go adapting the scooter motors to a chain drive? any advice regarding doing it? i know george had plans for this.

2) what is the better chain arrangement for driving 2 wheels from 1 motor? at the moment ive got an S-wrap tensioner system where 1 long chain powers both wheels, passes around the motor sprocket and a tensioner. is this optimal?

any help appreciated.
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Post Fri Aug 20, 2004 7:15 pm 
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Nexus
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You should just wait a couple of weeks till Oatley get their new stock in and see what new stuff they will have.

All you need is to decide on is a gear ratio. IN regard to chains there is no right or wrong just what is more important to you.

Personally I dont like the idea of taking a hit to one wheel and losing 2 so I would have seperate chains on each wheel for combat purposes.
Motor shafts are long enough to hold 2 chains to do this with.

Also try to keep chains as short as possible to reduce stretching.

Scooter motors are meant for chains so that part is fairly easy, its the rest of the drivetrain thats a pain to work out.
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Post Sat Aug 21, 2004 5:09 pm 
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Glen
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thanks george,

i was looking at using the wheels with built in bearings and bolting the sprocket onto the actual wheel.


quote:
Motor shafts are long enough to hold 2 chains to do this with.


so you can fit two sprockets onto the scooter motor shaft? that would be a real life saver.
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Post Sat Aug 21, 2004 5:21 pm 
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Nick
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I'm with George on the idea of running seperated drive to each wheel, although if one chain comes off there is a very good chance it will tangle the other chain.

Before you go buying materials, I have 10' of #25 chain, ehich is way more than I need. If you want to get half, just let me know.

From the sounds of it, Oatley will sell out all their next shipment in record time Smile
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Post Sat Aug 21, 2004 7:45 pm 
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timmeh
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Which would be better for drive with a ev warrior motor and a 2kg bar 1-2 ratio

Chain or belt?
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Post Wed Sep 01, 2004 8:38 pm 
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Knightrous
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I would use a belt if running a spinning bar of an EV, will save bending the shaft if you get a solid whack with chain.
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Post Wed Sep 01, 2004 9:01 pm 
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timmeh
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Would i get the same power out of the weapon?
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Post Wed Sep 01, 2004 9:03 pm 
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Totaly_Recycled
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Well heres a few pro's and cons to help you decide
________-----------------------------------------------______________
Chains
Pros: They are strong
They transmit power reasionably effecivily but stil have some small friction losses.
Power is transmitted with out slippage losses

They can be used effectivly for timeing various components in a machine
------------------------------
Cons : They are heavy combined with sprockets

They need to be well alighned or they will catch and come off the sprockets .

They will stretch especialy if they are loladed and unloaded extremely hard like hiting something with a bar ect and the pins can break with snap loading .

They dont like to be run on their sides ie horizintal as the weight puts them on the edges of the sprockets and iff they go slack can easily catch and run off .

They are noisy at high speeds
-----------------------------------------------------------------------------------
Belts .single V type
____________________
Pros ; can transmit power smoothly .

They will stretch or slip before they break

They are much lighter than chains

They can be run out of allighnment and still transmit reasonable power with out comeing off pullies.

They can be used to change direction of power tranfer around corners ect .

They can be twisted to run from a horizontal shaft to power a vertical shaft and vise verser .

They can be tensioned and un tensioned and used as a clutch system .

Cons -------------------------------------------------

They will slip under exteme loads

They are easiler cut that chain .

Most dont like being bent backwards . ie around a pulley then under an ideler ( unles they are specialy made belts with nylon or kevlar rope in them instead of the cheaper laminated webing types)

They can slip at very high speeds due to centrifical forces makeing them leave the pullys .
_-------------------------------------

Multiple v belts
==========
Pro's
These have more friction surface than single v belts so wont slip as much .

Most will go backwards around tensioners and pulies ect with no ill efects .

They are lighter in cross section so dont distort as much at high speed like single v belts and arent as afected by centrifical forces.

Cons
----
They need to be well alighned as like chains they can run off the pullys if too far out .
They will slip under sever loading
They are more expensive than single v belts .
Pullies are harder to find and also more expensive.


Timeing -- toothed type belts

-----------------------

pro's
These are much beter for transmitting high torque and uneven loads with out slippage.

Can be used for timeing moveing parts.

Most types can run backwards over tensioners ect with no ill effects .

Cons
-------
These belts need to be well alighned or they will run off the pulllies .

They are more expensive and harder to find in various sizesand pullie's are more expensive .






.

Post Wed Sep 01, 2004 9:39 pm 
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Valen
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our multi rib v belts dont slip even with stalled motors.
we made them and the pullys on the lathe, total "system cost" probbly ~$15 for a complete reduction.(ex bearings and the like which was about $40 or so for both sides combined (and wepon) i believe)



might slip a little on wep possibly but not too much
big advantage over metal on metal gears is they dont break, metal gears are real sensitive to lineup issues and dont tollerate shock loads well (think of it, all the force is transmitted through the one or possibly 2 teeth that are touching)
also belt drive is quitet, Stealth Bot plan-B is lol
well it would be with a castor or something lol.

Post Thu Sep 02, 2004 12:45 am 
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timmeh
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I am thinking of useing a car tyer tube to make my belts "will make it a very tight fit" and use two normal pullys 1-2 ratio

Will that work?
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Post Thu Sep 02, 2004 5:26 pm 
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Totaly_Recycled
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Dont even bother useing car tubes ect as belts as you will be disapointed .
ordinary rubber stretches like a rubber band they will slip and fly off iff you get them to drive at all if you make them real tight then they will just rob your motor of power and will probaly still come off.

Belts need to be strong and made so they dont stretch the rubber or other compounds on belts are mainly to give flexibilty and grip .
on the drive surfaces

Olden day belts were made from leather and ran on lage flat pullys most of the pullys were of large diametors so the belt had a lot of surface for friction . if you made a leather belt and managed to put rubber on the friction side it might work .
But it is a lot of mucking around unles you have acces to proper belt cords and grippy compounds and make moulds to make the belts like Jake and His father made it would be better just to buy them ..

Post Thu Sep 02, 2004 8:07 pm 
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timmeh
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BUGGER!

Im looking for light weght timeing belt that comes in short lengths and i can get steel pullys for it.

Can any one help me?
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Post Sat Sep 04, 2004 7:07 pm 
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Philip
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Have you tried a hoby shop?

Post Sat Sep 04, 2004 9:11 pm 
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timmeh
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No not yet but the belt has to run of a ev motor with a 2kg spinning bar 2-1 ratio i dont think a hoppy shop sell something like that Confused

i may just have to go chain drive
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Post Sat Sep 04, 2004 9:16 pm 
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Philip
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You are correct. Those belts would not stand up to being used on a weapon drive.

Post Sat Sep 04, 2004 9:32 pm 
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