High power RC motor and drive unit production

Hi Matt,

recumpence said:
Wow, quiet lately!

----Insert cricket sounds here----

Only 5 of the first 12 are spoken for so far.

Hmm, I'm glad I didn't make more than 12 to start with.

Who else wants one?

Matt

Sorry for the late response. The small company I do contract work for just signed a contract which depends on me coding and testing a large program with a very aggressive schedule.

I also ran into some issues with my "Series Drive" plan. I decided the best bet for the series drive I am hoping to use will be to mount a jackshaft, with the required sprockets, on the swingarm between the chainring and the rear sprocket. Then connect the single stage version of your drive to the jackshaft which would give me a second stage reduction.

My original plan was to try to mount the jackshaft directly above the chainstay between the Bottom Bracket and the rear sprocket. I knew it wouldn't fit but thought if moving the rear wheel back 3" or 4" max would work I would do it. When I measured it I discovered I need would need to move the wheel back 6.1" with a 26" tire or 5.1" with a 24" tire which I think is too much (don't think its a good idea to increase the wheelbase that much due to the suspension and doing it properly will be more complex and expensive).

I always thought there was a very good chance that wouldn't work so my plan b was to mount the jackshaft above the chainring. Before I even tried that I realized :oops: :oops: that the options are very limited because the chain from the rear hub will need to clear the chainstay (the bottom run of chain is under the chainstay so the options for running that chain to a location above the chainring where the chain doesn't hit the chainstay are limited).

So my 2 current options are:
1. When I have the time see if there is a way to mount a jackshaft above the chainring. Due to the limited time I have right now this might take a couple of weeks to work out. If it will work I will be ready for a single stage version of your drive.

2. If it won't work (which is seeming more likely) I need to figure out how to connect to the crank (most likely on a different bike) with a dual stage version of the drive. If I do it via a dual stage I should probably wait until the kv of David's motor is decided so I can order a drive with the correct reduction.

So the bottom line is I will eventually order either a single or dual stage drive but it could be a while. If you want a payment or deposit let me know.

A few days ago I spent about 30 minutes cobbling together a simple drive model to help determine how it will fit. I was not sure what size to use for the big pulley and sprocket. I think I will need (depends on Davids motor specs) between 12:1 and 16:1. I used 3 3/4" for the pulley and 4" for the sprocket. I am attaching a picture in case the idea helps someone else.

DriveModel.jpg
 
Hi Mitch,

your drive wont be very good im afraid Mitch, your concept isnt bad but your choice of materials leaves a lot to be desired :lol:

why don't you post us a few good shots of your swingarm - we may look differently at the problems and come up with something?

cheers,

D
 
What is the max reduction the single stage drive is capable of, while still allowing me to use a 203mm disc brake with left side drive?(if that is even possible)
 
Single stage can go as low as 6 to 1 in the drive itself. However, that limits the wattage handling to roughly 2kw due to minimal tooth coverage on the small motor pulley. As for the ratio down to the rear sprocket, I am not sure about that.

Matt
 
I think I need 11 or 12:1 total reduction assuming a 135 kv on the motor @ 48v. That would get me in the 43-46 mph range I guess it would be simpler to use a good rim brake, what do you use on your recumbent?
 
Rim brakes are generally fine as long as you have a disc on the front.

My recumbent has the stock catilever rim brakes in the rear. They are terrible compared to my disc brake. But, I rarely use the rear brake anyway. I figure it is there mainly for emergency purposes if my front brake fails. For that it is fine.

On my #2 bike I am using disc front and rear even though that bike will never see anything over 30mph. However, the disc brake in the rear is for regulation of wheelies. :wink:

Matt
 
Hi D,
deecanio said:
Hi Mitch,

your drive wont be very good i'm afraid Mitch, your concept isn't bad but your choice of materials leaves a lot to be desired :lol:

For my first version I copied Matt's original Ebox design using gears instead of belts/chains and it worked fine :lol: :
a2226065-127-100_1767.jpg


I figured I could copy his new design using similar materials. But that was a model. For the production version I plan to upgrade from Pine to Locust or Oak with Schedule 40 PVC shafts. :D


deecanio said:
why don't you post us a few good shots of your swingarm - we may look differently at the problems and come up with something?

D

Thanks! As soon as I have the time to check it closely I'll do that. Either with a request of help or hopefully with a proposed solution.
 
MitchJi said:
For my first version I copied Matt's original Ebox design using gears instead of belts/chains and it worked fine :lol: :

a2226065-127-100_1767.jpg


I figured I could copy his new design using similar materials. But that was a model. For the production version I plan to upgrade from Pine to Locust or Oak with Schedule 40 PVC shafts. :D

You might want to look into this advanced product called MDF it has fantastic strength, is impervious to water, doesn't rust and is easily worked with
hand tools all in all though its a cracker design and i think Mr Recupence might just have some competition on his hands :p
 
Hi,

Sorry if this seems like a foolish question but why not use V-belts for the second stage and/or between the drive and the cranks?

Gary posted that someone uses V-belts with Etek Motors and there is some slippage at very high power levels which provides some protection for the Nexus hubs.

Properly set up would it slip too much or could it work like Matt's slipper clutch?
 
Not a bad question at all!

The issue with V belts is efficiency. Their efficiency is very low.

I have recieved motors and mounting specs for a number of customer's drives just today. I will be at the shop Monday machining face plates! :mrgreen:

Matt
 
OK, I am nearly finished with a couple drives. I have done face plate machining, shaft manufacturing, bearing seating, and I am now doing final assembly.

For those who want a drive, there are still a few available. Gary will have his pretty soon. The next few will trickle out as I recieve the remaining bits (special belts, pulleys, etc).

Matt
 
recumpence said:
OK, I am nearly finished with a couple drives. I have done face plate machining, shaft manufacturing, bearing seating, and I am now doing final assembly.

For those who want a drive, there are still a few available. Gary will have his pretty soon. The next few will trickle out as I recieve the remaining bits (special belts, pulleys, etc).

Matt

We need photos! :D

The desire for a 3rd project: lightweight non-hub lipo road bike is strong, but the Aussie dollar is week :D 8)
 
recumpence said:
OK, I am nearly finished with a couple drives. I have done face plate machining, shaft manufacturing, bearing seating, and I am now doing final assembly.

For those who want a drive, there are still a few available. Gary will have his pretty soon. The next few will trickle out as I recieve the remaining bits (special belts, pulleys, etc).

Matt
I still want one, but I need to figure out the numbers for gearing.
I think I will need 11 or 12:1 total reduction assuming a 135 kv on the motor @ 48v. Is this doable with a single stage drive? You said 6:1 was possible within the drive, then I would need 2:1 to the wheel right? I would like to use a nice 16t eno free wheel for the output, and would like a little more than the 2kw potential the 6:1 reduction allows if possible. What should I do???
I am working on getting the wheel put together, I plan to use a Sun Rhyno Lite rim with a surly singlespeed disc hub for left side drive.
 
I would say it would be best to go with 5 to 1 ratio, then 2.5 to 1 to the wheel. That would give you the power handling you need with the reduction you are looking for.

What part of Indiana are you in? I live an hour horthwest of Chicago.

Matt
 
recumpence said:
I would say it would be best to go with 5 to 1 ratio, then 2.5 to 1 to the wheel. That would give you the power handling you need with the reduction you are looking for.

What part of Indiana are you in? I live an hour northwest of Chicago.

Matt

Sounds good:)
I live in Indianapolis. Maybe I could stop by sometime when I have the wheel made and some money saved up?(currently saving for A. Wedding/House, B. Ultimate e-bike... guess which one gets priority :cry: )
 
Hi Matt,

recumpence said:
I can send you a drive and wait on the exchange rate to improve. :wink:

Matt

Can North American customers also buy now and pay when the Aussie exchange rate improves :D ?
 
Hi Matt,

Gary's finished drive................

It looks like a 1900s steam engine.

Matt

I didn't realize that 1900's steam engines had that high a quality of workmanship. 8)

What is the overall width?

Too bad the pulley shoulder and the FW adaptor shoulder add so much to the width. Any way to reduce the width of the pulley shoulder?

Somewhere (D's build thread?) the topic of keyed shafts came up. I wondered if 1/2" shafts with key slots were available ready made:
http://www.robotcombat.com/store_shafts.html
Our cold rolled steel shafts are fully keyed along the entire length, and may be purchased in lengths of 18", 36" or 72".

Finish is flat, non-polished for regular use. Diameter tolerance +.000" and -.002". For maximum durability, we recommend your shafts be hardened by a heat-treating service once you have cut them to length and done any further machining.
Shaft Dia. 1/2" Price/in.$1.04

http://www.trukey.com/
TruKey® Shafting from Keystone is designed to provide the straightest, most accurate pre-keyed shafting in the industry. We stock keyed shafts in the most common diameters with standard keyways, and can provide it cut to any length up to 20'. TruKey® shafting is available in turned ground and polished carbon steel for an accurate diameter as well as 1018 cold finished steel and turned, ground and polished stainless steel. All keyed shafting has chamfered ends for easy installation.

Keyed shafting is available in lengths up to 20 feet and diameters ranging from 1/2" to 4 1/2".

http://www.huyett.com/catalog/index.php?cPath=22_50
Shafts commonly available in round, hex, or keyed shafting in every grade and tolerance the world has ever known. They typically come in lengths of 12, 36, or 72 inches and can be cut or filed for use in applications. Special milling is available.

Length's 3" to 5" $7.76:
http://kmac-distribution.com/shafts/index.htm
Shafts - Keyed, Precision, Tapped and Threaded
http://kmac-distribution.com/shafts/hardened-precision.htm
1566 Steel - Straightness Tolerance .002" per Ft., 12rms Micron Finish, Case Hardened, Rockwell C60, stronger than stainless steel, but are less corrosion resistant.

303 Stainless Steel - Straightness Tolerance .250" OD, .0036" per Ft, .375"-1.25" OD, .0004" per ft, 10-16rms Micron Finish, Rockwell B83

http://www.leelinear.com/products/
http://www.leelinear.com/products/shafting.aspx
LEE LINEAR's new automated hardening system utilizes a state-of-the-art electromagnetic based proprietary hardening system, to produce the next generation of Precision Shafting. With the new automated hardening technology, a consistent and precise case is accurately controlled by computer. The result is a thinner case as durable as standard case hardened shafting, with the same hardness and load carrying capacity. The LEE LINEAR Precision Case Hardened Shafting is suited for applications requiring long shaft lengths because of its ability to maintain better straightness with reduced distortion. All LEE LINEAR's shafting is demagnetized, and shafting diameters of one inch or less are rotary straightened to remove any kinks, or bends in the material.

Anyone machining case hardened and ground steel shafting will appreciate the product’s ease of machinability!

Their supports look a lot like your mounts:
shaft_support_150.gif
 
I mill two set screw flats in each end of the shaft for the pulley and FW adaptor set screws.

I have leaned away from keyways for a number of reasons. Anyone can add their own keyway shaft easy enough, though, if they want to. No biggie. :)

The drive as you see it is 4.25 inches wide. With freewheel it is about 4.5 inches wide.

It weighs 27 ounces as you see it.

Matt
 
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