Nice 5:1 gearbox

I took another power source with 48V/40A limit and the clutch worked much better. The sweet spot for the clutch seems to be around 3500RPM. The motor took all he could get, which was 1700W. After 30 seconds the blocked clutch startet to smell badly and I had to stop the test.
I will repeat the test outdoors next weekend and use the test-function from the turnigy servotester, which will run the motor from still to full and back in 3-4 seconds or thereabout. If all things go well, I'll use the watercooled aquastar 240 for this test and see, how it can handle the 'race simulation'.
A video of this torture is mandatory :D
-Olaf
 
Just received the same gearbox from ebay seller and noticed quite a bit of resistance when turning the clutch bell. If this is normal for this unit then I'm afraid it will be too lossy for my application. Did you notice the same with yours. Perhaps I received a bad unit. Once I get the chance I will open it up to see what's going on. I will also ask the seller if this is normal.
Martin
 
mauimart said:
Just received the same gearbox from ebay seller and noticed quite a bit of resistance when turning the clutch bell. If this is normal for this unit then I'm afraid it will be too lossy for my application. Did you notice the same with yours. Perhaps I received a bad unit. Once I get the chance I will open it up to see what's going on. I will also ask the seller if this is normal.
Martin
Click to expand...
Turning the bell by hand felt a bit 'greasy', but it turned out that the motorcurrent wasn't much higher than running the motor without gearbox ( IIRC 50Watt more ). There is a bit of grease in in the gearbox, that can be replaced with something more fluid.
-Olaf
 
Hi olaf-lampe,
Have you tried your clutch without anything to return the shoes ?. I read that you have removed the springs and replaced with foam. This clutch seems so much smaller than the ones on a autoscoot so I know things will be different but on the clutch on my scooter I was getting very strong engagement without any springs at round 1k rpm.
 
olaf-lampe said:
mauimart said:
Just received the same gearbox from ebay seller and noticed quite a bit of resistance when turning the clutch bell. If this is normal for this unit then I'm afraid it will be too lossy for my application. Did you notice the same with yours. Perhaps I received a bad unit. Once I get the chance I will open it up to see what's going on. I will also ask the seller if this is normal.
Martin
Click to expand...
Turning the bell by hand felt a bit 'greasy', but it turned out that the motorcurrent wasn't much higher than running the motor without gearbox ( IIRC 50Watt more ). There is a bit of grease in in the gearbox, that can be replaced with something more fluid.
-Olaf
Click to expand...

Olaf,
Thanks for the response. By slightly loosening the 3 bolts that hold the unit together, the friction went way down. Unfortunately these bolts need to be tight during normal operation. I have not opened the transmission yet - waiting to hear back from the supplier, in case I received a defective unit, before I look inside.
Thanks.
Martin
 
Mine loosened up a bit after "break in" on the bench. I think its normal for a cheaper gearbox to need to "wear in" to its housing due to loose tolerances and such. I am back in the game and should have some results from the gearbox in the next few weeks, I am trying to get this thing done and dialed in by the time our baby girl comes into the world so my wife can go with me on rides on my old Schwinn Protocol 1.0 Hubbie motor bike pulling the baby trailer!
 
Here is a video of the first try of my setup almost a year ago I think! The noise is from the sprocket dragging on the plate because I tried to make an adapter without a lathe and it wobbles a bit.... anyway, here it is..

[youtube]GU8SV2RHjOg[/youtube]
 
olaf-lampe said:
I ordered some sprockets from 11 to 21 teeth And also two rear sprockets with 44 and 54 teeth. This way I can adapt it to any wheel size and topspeed I like. Slowest ratio would be 1:25 and fastest is 1:10
With the clutch I'm able to use a smaller and cheaper ESC without taking the risk of frying it at low RPMs.

-Olaf
Click to expand...
Hi Olaf,

Have you had a chance to do much testing with this? Can you give us an update about it?

Thanks! :D
 
I posted this image in another thread last year, but since this thread (where I got the idea from) was ressurected,
it might be good to post it here aswell. Worth to note is that my gearbox looks very similar to the one with the helical gears earlier in this thread.
Mine however has strait gears and is therefor probably more noisy. Overall my setup is abit too noisy, but works very well in other regards.

Hiding under the heatsink (that also acts like a flywheel) is a hyperion z5045mm or whatever it is called.

motorochslirkoppling.jpg



I threaded the motorshaft and made a cone that would fit the centrifugal clutch. A low profile nut presses the clutchwhhel onto the cone and locks it in place.
Also had to press the clutchplate and make it alittle deeper to not interfere with the motorshaft/nut.

Slirkopplingpkona.jpg



It is fairly quiet during acceleration, but when the motor tops out around 50km/h and the torque in the driveline lowers, the drivline is singing too much.
The biggest concerns with this setup is the flexibility of the bikeframe and rear wheel spokes breaking from exhaustion. Have seen around 4kw peakloads during accel.
 
Very nice there any vids in action?
 
Looks good

I have researched a lot for centrifugal clutches good for an RC setup, before I decided to suspend my build from scratch and convert my personal FR bike.
I also had promising contacts with a pair of italian small manufacturer of racing minimoto clutches that have the closest motor specs to the bigger RC ones (mine is a 3220 astro) and are smaller compared to the kart ones that otherwise have a better default rpm engage range.

If I can ask, what kind of clutch is it?, what the rpm range of engage? how long those pads last for your setup?

Anyway, it's a good work, very interesting.
 
It is some clutch i bought from ebay. I remember it was labelet as a pocketbike racingclutch.
The engage rpm with stock springs was high, it actually slipped at maxed speed :)
I replaced the springs with about as soft ones i could find so the clutch starts to engage almost immidietly now.
That is no problemn tho, as it will slip until i apply enough throttle to actually push the weights enough to the plate to give traction.

My clutch spins the wrong way, and that is not ideal. It makes it harder for the clutch to engage supersmooth.
I have plans to replace the gearbox with a beltreduction and that will change the direction of the clutch, aswell as reduce noise.
To ensure a very soft and controllable engagement i lube the clutch from time to time. I use some spraylube that dont make it messy like grase would.
If the clutch spun the right direction i bet I wouldnt have to do lube it.

There have not been much wear on the clutch at all, the pads seem to be very durable and this setup is probably much nicer to the pads than the intended application.

Have no vids unfortunately, I have a gopro2 now tho, so next summer I would be able to film it.
Its winter so the bike wont see any use until April or May.
 
So are there any more projects using this 5:1 gearbox?

Im also considering using it but what I dislike right now is that it would be placed on top of wheel, most likely.

That is because most bike frames dont have enough space between rear wheel and triangle frame and fitting inside triangle seems like extra hassle, as then rear wheel cant be powered directly but power would go through crank / front gear. And then crank with freewheel is needed.

I also thought about idea to mount outrunner RC motor on top of gearbox, thus saving space but not entirely sure about this idea as that would require extra transmission step and gear ratio is good enough with stock 5:1 ratio + what output gear and wheel gear would give.

So yes, very interested to see that this idea was brought out in 2010 already and still same gearboxes are available.

Would love to see some more implementation of these, seems like very cost effective solution to use for these who dislike hubmotors or want to use RC motors for other reasons.

As about the clutch drum.. im also thinking whenever to use the clutch at all, seems like in some cases it just causes some hassle
 
Not necessary. For heavy bikes use a big motor and if necessary single stage reduction. For bicycles, same applies but you can use multi-stage thru the bike's drivetrain if using a mid drive.
 
Mh yes, Im still not sure how to mount external / extra sprocket on the rear wheel anyway. The current bicycle has disk brakes (dirt / jump style frame) so I would either need to remove them or somehow make the gear larger while still retaining the brakes probably (unless regen braking would be very effective, thus not needing disk brake)

Then again, If I wanted to mount it as middrive, gearwise it would be easier but I would need freewheel and as far as I know these alone tend to cost close to 100 eur / 110usd more or less.. so it increases the cost substantially.

Right now Im having bigger hurdle deciding on gear ratios and what gears to choose. I havent really decided on what voltage I would run it anyway, but I guess I should aim for 44.4v nominal (12s).. to keep the amps low, as I dont see much point running 100+ amps with 6s controller here.

So yes, if it produced 2-3kw that would be quite decent, I think. Current outrunners I have are not rated much higher anyway and from experience I know they get relatively hot at 40A constant, so I wouldnt push them beyond 50-60Amps for sure.. (at ~45v, that would be around 2-3kw)
 
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