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2 speed (could be auto) gearbox

Posted: Sep 14 2010 3:25pm
by gwhy!
I thought I will start a new thread but this was inspired by this thread http://endless-sphere.com/forums/viewto ... 28&t=10908 from miles.

I managed to get some me time today and made a start on a prototype 2 speed gear box that is really to test the concept and to play around with the electronics for switching the direction of the motor.

when driven by the motor in the initial direction it will be one gear but if the motor is reversed the second gear is auto selected.

There is a bit more work to do but I hope to have it finished and start bench testing next week sometime if all goes well but here are some pics in the meantime :D .
GB1.jpg
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gb2.jpg
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Re: 2 speed (could be auto) gearbox

Posted: Sep 14 2010 3:42pm
by Miles
8) You'll be the first to have one working. :)

It's similar layout to this: http://www.endless-sphere.com/forums/vi ... 25#p131525

Image

Re: 2 speed (could be auto) gearbox

Posted: Sep 14 2010 3:49pm
by gwhy!
Miles wrote:8) You'll be the first to have one working. :)

It's similar layout to this: http://www.endless-sphere.com/forums/vi ... 25#p131525

Image

:D I missed that thread as well :oops: Thanks :mrgreen:

Re: 2 speed (could be auto) gearbox

Posted: Sep 25 2010 12:28pm
by gwhy!
I wish I had more time on my hands ( unlike some cough, cough, KiM :mrgreen: ) I havent touched the GB till today but still am not in a position to test anything yet ( but I'm a lot closer 8) ). So this post was really to give it a little bump.

Re: 2 speed (could be auto) gearbox

Posted: Sep 25 2010 6:19pm
by AussieJester
gwhy! wrote:I wish I had more time on my hands ( unlike some cough, cough, KiM :mrgreen: ) .
:mrgreen: :P

KiM

Re: 2 speed (could be auto) gearbox

Posted: Sep 25 2010 7:36pm
by liveforphysics
Wow! Awesome work!

Re: 2 speed (could be auto) gearbox

Posted: Sep 28 2010 4:54pm
by ev_nred
any plans on selling something like this? anyone? just thinking that the markect for something smillar for small powered motors like 250w would be nice....

Re: 2 speed (could be auto) gearbox

Posted: Sep 28 2010 5:11pm
by gwhy!
ev_nred wrote:any plans on selling something like this? anyone? just thinking that the markect for something smillar for small powered motors like 250w would be nice....

Im Not planning on making and selling this but if it works out it is very easy to make with off the self bits and a bit of machining. I would have thought it would not cost that much to take the bits to a machine shop and have them drill the holes ( im sure they can do a better job than I have done as they will all the proper tools and know how). If I was going to make another I will make it differently as the mistakes that I have made in this little exercise have taught me alot :mrgreen: .

There is one major draw back with the design that is the GB will lock if driven backwards through the output shaft which at first I did not think it would be much of a problem for a pushbike i.e the bike will not free roll backwards, but the more i think about it the more i dont like it .... :( ,,, so can anyone think of away to get round this because I cant at the mo :?

Re: 2 speed (could be auto) gearbox

Posted: Sep 28 2010 6:58pm
by Hillhater
Freewheel on the output shaft ??

Re: 2 speed (could be auto) gearbox

Posted: Sep 28 2010 9:14pm
by AussieJester
LOL GWhy i didnt realize it at first myself when i bolted the cranks to the frame of the crusier, first ride belt comes off and i couldnt roll backwards to get it back on ... Simple fix for me would have been a set of freewheeling cranks, can't (as suggested by post above) incorporate a freewheel somehow? I'm sure Miles will have a solution?

KiM

Re: 2 speed (could be auto) gearbox

Posted: Sep 29 2010 1:43am
by Miles
It's a limitation we discussed in the earlier threads. You can't avoid it by using another freewheel, at any point. For a roller drive, you can disengage the roller, of course. For other applications, if it isn't possible/acceptable to take the weight off of the back wheel and drag, you'd need another way to completely disengage the drive. A lever operating a cam tensioner on the belt drive stage is a possibility.

Re: 2 speed (could be auto) gearbox

Posted: Sep 29 2010 2:13am
by AussieJester
awwww Miles I assumed the limitations of mechanics and even the laws of physics didn't apply to you, you disappoint me :P :lol:

GWhy lifting the back wheel to go backwards wouldn't be that limiting for you guys would it not as if bicycles or motorcycles for that matter have reverse gear anywayzs, bicyles light enough to drag the wheel as Miles suggests or simply pick up the whole bike and turns him round, i think the positives of the gearbox outweighs the inability to roll it backwards doesn't it?

KiM

p.s hahaha sorry, can't resist this one GWhy... :: clears throat:: you can make a 6fet Infineon take a sustained 8kw but can't make a gearbox that allows you to roll backwards whats with that man! c'mon lift your game buddy :mrgreen:

Re: 2 speed (could be auto) gearbox

Posted: Sep 29 2010 3:54am
by gwhy!
AussieJester wrote:awwww Miles

p.s hahaha sorry, can't resist this one GWhy... :: clears throat:: you can make a 6fet Infineon take a sustained 8kw but can't make a gearbox that allows you to roll backwards whats with that man! c'mon lift your game buddy :mrgreen:
:mrgreen:
Im Lifting it mate :D
Now I have slept on it I may have thought of a solution but will not appear on this prototype.... I suppose it will not be to much of a problem for pushbike use for normal riding but for off road use or for motorcycle size bikes a way of rolling backwards would be necessary.

Re: 2 speed (could be auto) gearbox

Posted: Sep 29 2010 4:03am
by scouser-nick:)
why not make a clutch/coupler that when you would need to roll backwards you could disengage so the output shaft isnt connected?
i dont really know what im talking about but seems reasonable to me?

Re: 2 speed (could be auto) gearbox

Posted: Sep 30 2010 3:41pm
by gwhy!
Ok guys and guy'etts,
After having found a bit more time to fettle with the GB I have decided to start again :? I wasnt happy with the smoothness or the weight, I did connect it to a drill and spun it up forewards and backwards and it do work a treat so the plan is to remake the sides and instead of using roller bearings im going to use 12mm id needle bearings ( which should make it a tad easier to get it all lined up properly because the carrier hole size (18mm) is smaller than using normal bearings (28mm) and also I will try and incorporate a manual disengage lever ( disengaging the idler gear ) to enable the GB to run backwards via the output shaft. Just got to wait for some 10mm ali to arrive then Im sorted as I have all the other bits and pieces here ready to go.

Edit:
and also, so I can put some adjustment feature in so I will have the option to use a bigger MOD gear type.

Re: 2 speed (could be auto) gearbox

Posted: Oct 11 2010 2:55pm
by gwhy!
OK, I have finally ( after the third attempt :roll: ) have a working prototype using MOD1 gears and needle bearings that Im happy with. I have thought of away of dis-engaging the back drive problem but have not incorporated in this proto. Just a few things to tidy up with it and couple it with a motor then it will be tested/videoed to see how noisy it is and how strong.

Here are some pics: :D
GB1mk2.jpg
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GB2mk2.jpg
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GB3mk2.jpg
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GB4mk2.jpg
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Re: 2 speed (could be auto) gearbox

Posted: Oct 11 2010 4:47pm
by kevo
GWhy,
Nice to see your progress. What kind of dimensions and weight does your GB have? What materials and hardening? Sorry if these were already posted, I didn't see them.

Re: 2 speed (could be auto) gearbox

Posted: Oct 11 2010 9:44pm
by Whiplash
Nice! I love to see this kind of stuff! looking good Gwhy!

Re: 2 speed (could be auto) gearbox

Posted: Oct 12 2010 5:09pm
by gwhy!
kevo wrote:GWhy,
Nice to see your progress. What kind of dimensions and weight does your GB have? What materials and hardening? Sorry if these were already posted, I didn't see them.
I haven't weighed the GB yet as its not quite finished. The size is 3"X3.5"x2.5" The GB will coupled up with a 3250w outrunner, A gestimate of total weight when complete ( motor,halls,mounting bracket and external belt/pulleys ) 1.5kg to 2kg. The gears (MOD1) are steel but are not case hardened (yet) if this works out I will make another but with case hardened gears and shafts and will run in bearings instead of needle bearings. This is going to be more of a test bed to play with how fast can I reverse the motor direction ( to change gear ), Im not bothered about the noise that this GB will/will not make but am more concerned about it working well and handle the power levels that I intend to put through it :wink: .
Whiplash wrote:Nice! I love to see this kind of stuff! looking good Gwhy!
Thanks Whip, If this works out it will give me the the low end torque/power that I currently have with my bike but it will have a top speed of beween 40-50MPH :!: and still pulling no more than 70A @44.4v .. I just want to get it finished so I can start to play with the motor control 8)

Re: 2 speed (could be auto) gearbox

Posted: Oct 13 2010 10:57pm
by etard
That's badass GWHY! I have been thinking alot about the gearboxes in Dewalt 36 volt drills, they are supposed to have metal gears. :P

Fast gear changes will save the gears, no?

Re: 2 speed (could be auto) gearbox

Posted: Oct 14 2010 9:47am
by SHARKBITEATTACK
This looks awesome! What gear ratios will you be able to get?

Re: 2 speed (could be auto) gearbox

Posted: Oct 14 2010 3:35pm
by gwhy!
etard wrote:That's badass GWHY! I have been thinking alot about the gearboxes in Dewalt 36 volt drills, they are supposed to have metal gears. :P

Fast gear changes will save the gears, no?
Hi etard,
Thanks its getting there. As the gears will always be engaged, related engagement damage on the gears should not happen ( but the the weak point on this setup I think will be the oneway needle bearings press fitted into 2 of the gears ). Fast gear changes will help with this I think, we will have to wait and see.
SHARKBITEATTACK wrote:This looks awesome! What gear ratios will you be able to get?
Thanks, If it works out it will be quite a neat compact easy to make 2 speed gear box. The ratios on this at the mo is 2:1 and 1:1 but very easy to change the lower ratio or can go upto 3:1 without increasing the overall dimensions to much.

Re: 2 speed (could be auto) gearbox

Posted: Oct 17 2010 5:24pm
by gwhy!
Done a bit more on the GB... more pics...... I managed to fit proper bearings now and very happy with how smooth it is.
GB133mk2 nearly there.jpg
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GB134mk2 nearly there.jpg
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GB135mk2 nearly there.jpg
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Re: 2 speed (could be auto) gearbox

Posted: Oct 19 2010 4:36pm
by gwhy!
Small Update:
just a pic of the setup Im going to be using to bench test the gearbox.
GB testbed2.jpg
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Re: 2 speed (could be auto) gearbox

Posted: Oct 19 2010 4:51pm
by mwkeefer
gwhy,

in the post above, is that outrunner attached to just a mount or is that another reduction stage?

Great work, soon we will need valve bodies to control shift points? {kidding}

-Mike

PS: My 4 year old picked out a new book/toy, from Smart Lab called Motor Mania. Supposed to be for 8+ but he pointed out the pinion gear, the spur gear and idler and a few other bits properly... nearly all of em so I figured if he knows what they are and understands them why not. I only mention becuase once we built the first thing, he tried to make a friction drive for his 12" spiderman bike - best part, it worked if he wasn't on it (tiny little motor) it moved anyway...