RC motor / Neugart gear reduction unit (newbie questions)

[VSkudarnov]

I have a 360W 24V cyclone on my wife's road bike already.
After looking at some really nice RC builds (mostly on FR bikes) looking for a compact and powerful drive for my freeride bike (Kona Stinky). Not a 1200W 48V Cyclone - too wide/noisy/impossible to gear lower.

Location: under the downtube, mounted to the ISCG mount.
Motor: Turnigy 130kv
Reduction: Neugart ple60-80 20:1

Therefore, questions:
1. Motor to gearbox link: belt or chain? where do get the sprockets? how sprockets mounted on the motor shaft
2. Gearbox input shaft: I think it does not come with it - where to get?
3. Bearings: do I need additional support bearings, which ones?
4. Gearbox output shaft - a BMX freewheel has to be mounted - how?
5. Motor voltage: 48V best?
6. Overall gearing - how to calculate for a Turnigy motor 40T chainring / 75rpm at the cranks?
7. Batteries: have not decided (in the frame/in the backpack).

Thank you for your guru comments, really appreciated.

 

[www.recumbents.com]

Ok, since no one else will bite, here's my 2 cents:

1) Chain is easier, belts are quieter and better for high RPM. Parts can be found at mcmaster-carr or other industrial supplies.
2) The gearbox should have an input shaft
3) You will need to mount the gearbox somehow. It's a good idea to add some bearings in that mounting system.
4) recumpence will sell you a freewheel adapter, or work with a machine shop.
5) RC Motors / ESCs and other stuff are designed for a max of 50V, so most RC e-bikes go with 12S of LiPo, which maxes out around 50V.
6) Gearing - try this: http://www.recumbents.com/wisil/e-bent/rc_drive/rc_drive_calculator.asp
7) Batteries - The 6S 5000mah LiPos are a nice form factor, reasonably priced, and serve as good building blocks for a battery pack.

Hope that helps,

-Warren.

 

[VSkudarnov]

Ok, since no one else will bite, here's my 2 cents:
2) The gearbox should have an input shaft

Warren, thanks.

Anybody had the experience with Neugard reduction gearboxes?
From the Ebay photos, I do not see the input shaft, just a hole where the motor shaft has to go. But since I want to place them side-by-side, I need some sort of input shaft to mount the large belt sprocket. How do I do that?

 

[boostjuice]

You realise ES member 'burtie' has finished a similar project to what your after....Even using a Kona Stinky as the donor bike... Talk to him :wink:

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=12768&p=371533

 

[MitchJi]

Hi,

questions:
1. Motor to gearbox link: belt or chain? where do get the sprockets? how sprockets mounted on the motor shaft
2. Gearbox input shaft: I think it does not come with it - where to get?
3. Bearings: do I need additional support bearings, which ones?
4. Gearbox output shaft - a BMX freewheel has to be mounted - how?
6. Overall gearing - how to calculate for a Turnigy motor 40T chainring / 75rpm at the cranks?

1. 15mm wide 5mm pitch HTD belts are good for up to about 3kw. #25 chain, with a minimum of a 14t drive sprocket will be a little nosier, but not bad.
2. You supply the shaft. There is a clamp for the shaft. Standard size depends on the GB model. They also sell bushings (range of sizes varies with GB model). You can find the options here:
http://neugartusa.com/partners/PLE_PRICE_010.htm
These are the options for the PLE60:

Standard Motor Shaft Diameters (available bushings) - mm
6 / 6.35 / 7 / 8 / 9 /9.525 10 / 11 / 12 / 12.7 / max.D= 14

Their tech support told me the standard is the 14mm shaft size (I think no bushing). The bushing has a slot so it just slides into place and the shaft clamp still works. I asked how much the 12.7mm (1/2") is and she said "thats a standard size - $27" (so they will also make custom sizes).

These are the options for the PLE80:

Standard Motor Shaft Diameters (available bushings) - mm
9.525 / 10 / 11 / 12 / 12.7 / 14 / 15.85 / 16 / max.D=19

3. You will need a support bearing for the input shaft. I'd choose a shaft size that its easy to find bearings for and for easy sprocket mounting :wink: .

4. Sickbikes, Matt and Staton all sell FW adaptors for varying shaft sizes (you might need to pick a size thats close and drill one out).

6. Use kv * .85 * nominal pack voltage / reduction ratio.

 

[Timma2500]

My 2cents:

1. I'll be using #25 chain on mine, primarily to keep overall width between the cranks to a minimum ( i'm using a 128mm Truvativ DH bottom bracket). I used BBMAN.com to get my sprockets, great range and prices. The sprocket will attach to your motor shaft with two grub screws. Its advisable to get the sprocket in the exact alignment you need then partially drill two very shallow holes in the motor shaft for the grub screws to locate into. You only need to drill till the very outer diameter of the drill bit is cutting, its called dimpling.

2. Your correct, they don't come with an input shaft, normally when used in industry the motor is attached directly to the gearbox with its motor shaft used as the input shaft and clamped directly to the input snout. Checkout pictures of my box in my thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=12687&start=270 bottom of page 19.
Personally i'll be getting my 40t #25 sprocket bored out to slide over the input snout, then get a short bit of steel bar machined down to slide inside the snout. I'm counting on the 2 grub screws to clamp the sprocket against the machined bar inside the snout, holding it all in place. Time will tell if it works.

3. You may need additional support bearings for the outrunner and maaaaybe the input on the gearbox, Burtie may be able to better advise on this.

4. The Neugart 12:1 i got off ebay has a 20mm output shaft, a Cyclone freewheel adapter fits perfectly (got lucky!)

5. 12s lipo / 50v max

6. 130kv @ 90% no load speed @ say 48v is 5600rpm. To achieve 75 crank rpm divide 5600/75 = 75:1 reduction needed.
Assuming you use a 14t Cyclone freewheel to 40t crank sprocket (2.857:1), I'd suggest: 22t/30t or 30t/40t #25 chain and sprockets from motor to gearbox (1.363 or 1.333:1).
Together with your 20:1 gearbox, you'd achieve around 76:1 reduction from motor to cranks at max loaded rpm.

7. 12s lipo, atleast 10ah (depending on your required range), preferably in frame


Hope this helps VSkudarnov, i look forward to the build! :wink:


Paul

 

[Burtie]

My 2cents:

... You may need additional support bearings for the outrunner and maaaaybe the input on the gearbox, Burtie may be able to better advise on this.

Paul

Yes IMO you do require an additional bearing to support the radial load on the input shaft to the gearbox. As Paul says, this gbox is designed to bolt straight onto a motor, so the input is not designed to survive sideways loading.

The motor would probably benefit from the same treatment because the internal bearings are pretty small, though many have done it without.