Oil cooling your hub- NOT snake oil!

[macribs]

I would be interested in seeing pictures of the planetaries in starter motors. Might be about the right torque rating...

Handa 125cc starter. But was the best exploded view pic I could find.

 

[macribs]

I would be interested in seeing pictures of the planetaries in starter motors. Might be about the right torque rating...

Torque improvement via reduction gear:

A marine starter for boats, needs heavy torque cos the diesel engine.

When the key switch is turned to the on position, the engine control circuit is energized, and when the key switch is turned to the start position the start solenoid is energized and pulls in to supply current to the start motor.

The motor turns to bring the marine-engine up to a speed where ignition occurs. An electric starter consists of three main components, which are the DC motor, the solenoid, and the pinion engaging drive.

The DC motor must provide the high initial torque required to overcome friction, inertia and cylinder compression and accelerate the engine speed to a point where self-ignition temperatures and combustion starts.

This is typically in the range 60-200 rpm depending on whether glow plugs are used. The starter motor torque is transmitted by the pinion and ring gear onto the flywheel. Your marine-engine starter needs you!

 

[macribs]

Now someone mentioned a small automatic gear box as a way of getting gear. I am not sure about that. They usually comes with a rather heavy torque converter.


Maybe a CVT is more in line with e-bikes?
After all Lito Sora uses them, the coolest looking electric motorcycle ever.

A CVT is actually quite simple, comprised of just two pulleys connected by a belt. One pulley is attached to the crankshaft of the engine – this one is called the drive pulley. The other pulley, the driven pulley, is attached to the output shaft of the transmission. This is connected to the drive-shaft, which in turn rotates the wheels. The belt that connects the pulleys is usually flexible but made of steel for strength. Both pulleys have a deep V groove that can have its width adjusted by the computer in the transmission. As the width in the pulley grooves change, the belt rides higher or lower in each, changing the gear ratio between the engine and the wheels.

Small gear box

 

[Marc S.]

Now someone mentioned a small automatic gear box as a way of getting gear. I am not sure about that. They usually comes with a rather heavy torque converter.

Already available for bikes. Never heard about a Nuvinci 360 CVT hub? http://www.nuvinci.info
IIRC it can take at least 1kW.

 

[macribs]

Now someone mentioned a small automatic gear box as a way of getting gear. I am not sure about that. They usually comes with a rather heavy torque converter.

Already available for bikes. Never heard about a Nuvinci 360 CVT hub? http://www.nuvinci.info
IIRC it can take at least 1kW.

Not an auto, a CVT variation. Kind of like on snowmobiles, scooters and in the later years also various cars.

 

[amberwolf]

Sure you could use those, but unless you need the power-handling ability of those, things like the NuVinci CVT hubs (which can be used outside of the wheel, like a jackshaft) would work. You can shift them manually or there are automatic shifters for them.

 

[macribs]

Sure you could use those, but unless you need the power-handling ability of those, things like the NuVinci CVT hubs (which can be used outside of the wheel, like a jackshaft) would work. You can shift them manually or there are automatic shifters for them.

Ohh I thought NuVinci was for hub mount. But I finally looked at the video and I saw that it must be really neat CVT.
I wonder what kind of power the Nuvinci CVT can handle? Could it handle the power from the 7 kw hubmonster? or cromotor?

Or maybe an outrunner placed low in triangle center coupled to a NuVinci CVT?

 

[amberwolf]

Given it's design, I really doubt you could put that much power thru it for very long (if at all). If the startup torque was low enough it might work for a little while, maybe. There are also at least two versions of it (171 and 360), and some variations of at least the first, with specification differences between them. Not sure which handles more power, but the 171 had a devkit that was intended to help people develop small EVs using them as the automatic transmission. (though if you look at the warranty card (assumign they haven't changed it finally) for any NV hub, you find a statement that using it for any kind of non-human-power or using it mounted outside of a wheel voids the warranty, even though they have in several places (including my old http://electricle.blogspot.com site) encouraged their use in both of those ways).

But if you look around ES for "NuVinci", (or even "*vinci" in case someone used a space) you'll find a number of threads discussing it, and a few bikes using them for powered transmissions.

My own build that will use one as the jackshaft to the rear wheel (and also the pivot point for the rear swingarm so I don't have to deal with chain growth) hasn't gotten very far yet, but it's the first link in my signature.

 

[macribs]

Given it's design, I really doubt you could put that much power thru it for very long (if at all). If the startup torque was low enough it might work for a little while, maybe. There are also at least two versions of it (171 and 360), and some variations of at least the first, with specification differences between them. Not sure which handles more power, but the 171 had a devkit that was intended to help people develop small EVs using them as the automatic transmission. (though if you look at the warranty card (assumign they haven't changed it finally) for any NV hub, you find a statement that using it for any kind of non-human-power or using it mounted outside of a wheel voids the warranty, even though they have in several places (including my old http://electricle.blogspot.com site) encouraged their use in both of those ways).

But if you look around ES for "NuVinci", (or even "*vinci" in case someone used a space) you'll find a number of threads discussing it, and a few bikes using them for powered transmissions.

My own build that will use one as the jackshaft to the rear wheel (and also the pivot point for the rear swingarm so I don't have to deal with chain growth) hasn't gotten very far yet, but it's the first link in my signature.

I will read up
If you use one as a jackshaft how would that setup look? I mean would you put the Nuvinci right in the front of swing arm?
Or would you mount it to the front sprocket? That option would require some kind of "freewheel" or the pedals would move even if you "fly by wire" rather then peddle.

 

[amberwolf]

If you use one as a jackshaft how would that setup look? I mean would you put the Nuvinci right in the front of swing arm?

Yep. it would be what holds the swingarm to the bike frame; the swingarm would ride on bearings on the NV axle (well, acutally on yet-to-be-machined thread-on "nuts" to go over the axle, since the axle isn't actually long enough to do it how I want).

There's some variations of the idea in that thread and it's successor (or predecessor, I forget which), some of which are sketches and some are pics drawn over, etc., and some just descriptions. I don't know that any of them will acutally work, yet.

Or would you mount it to the front sprocket? That option would require some kind of "freewheel" or the pedals would move even if you "fly by wire" rather then peddle.

There is a way (with a thread about it somewhere on ES) to put two single speed freewheels on the input to hte NV (or any hub), using a BB bearing cup to "add threads" to it, and that or a similar method will let me have a freewheel for hte pedals, and also one for the motor. So if something goes wrong with the motor setup and I have to only pedal, I wouldn't be backdriving the motor and wasting pedal power with that. And if I am not pedalling but only motoring, I won't hav epedals backdriven by the motor.

I also considered freewheeling cranks (which there are a few ways to do) but then the chain is still being driven, and since it's being backdriven then it must be setup so it can't derail in that case (which is different loading/etc than under pedal loads). It's harder to get right, and adds noise (moving chain that doesn't have to), so I won't do that unless I have to.

But it is possible that all this extra stuff, NV/etc, will end up making the system less efficient to the point I have to use enough more power in the motor to get the same speed/torque/etc that it would be better to not have a transmission. :lol:

I'll have to build it to find out, though.

 

[macribs]

NV and similar CVT's does take care of some problems with electric motors, let us just hope such a solution introduces new and maybe even worst problems.

It should be easier to get a better acceleration, while the motor still get to work in the most effective range of RPM.
Also climbing hills should be a lot smoother with less heat generation to the motor. '

I see NV try to market their CVP as a gearbox for all EV's, they even put one on an ATV to tow a pick up truck.
Yet I can not find any specs that does go into details about what loads and horespowers NV will withstand.

If one could have both great acceleration and great top speed all in one bike, heck yeah. I am in.

 

[amberwolf]

I think that info was avaialbe in the NV devkit thread, but not sure. I know the N171 (taht the devkit was for) coudl do "Maximum Input Torque: 130Nm (96 ft. lbs.)" copied out of it's tech manual PDF file I have here, and it's also got a spec for "Minimum Allowable Chainring/ Freewheel ratio: 2 to 1 (Example: 32/16, 44/22)", so even though it doesn't say how much power it could take you could probably make some estimate based on that ratio and known human output power?

Some build threads for bikes with them also specify input power to their motor system that drove them, and at least one states some efficiency numbers for power out at hte wheel vs input power to the motor (which basically leads one to the conclusion that above a certain level it's a lot less efficient, is probably slipping inside and causing that?).


might also be in the pdf's on the fallbrook 360/harmony pages, but I can't open most of the ones downloaded from there, they say they are corrupt. COuld be my computer.
http://www.fallbrooktech.com/cycling/download-page?language=74&field_category=93"


It also used to be directly on the Fallbrook site but tehy've totally reorganized it now, and there is no useful specification information directly avialble anymore, just a bunch of hype and press stuff rather than any details of actual product. If it's not in those PDFs above, you'd have to contact them directly to get the details of whatever the present models do, I guess.

(they do have SOME info, like this in the FAQ, but it isn't enough):

Question:
Can the N360™ be used with a motor?
Answer:

The N360 can be used on ebikes with electric front hub motors and mid mount motors of 250 watts or less. Powering the hub with more than 250 watts voids warranty coverage. Using the N360 with any type or size of combustion engine also voids warranty coverage.




Question:
What is the ratio range and efficiency of the NuVinci® N360™ Drivetrain?
Answer:

From bench and road testing by potential consumers and industry experts, the NuVinci N360 drivetrain compares favorably with internally geared hubs on the market today and has the same or better ratio range. The nominal ratio range of the N360 Model is 360%. In a double front sprocket installation, the range is significantly larger. A gear inch and ratio range comparison chart is available in Product Documentation -- N360

Oh, and if you want *something* for high torque vs high speed, you could use something like Thud's 2-pseed dog clutch gearbox (there'sa trhead for it somewhere with details). It's not as smooth as a CVT would be, but it is probably a lot more efficient, and lighter/smaller. AussieJester used one on at least one of his custom bikes.

You coudl even get "four speed" out of it by also setting up the (BLDC 3-phase) motor for delta/wye switching on ti's phase wires, though I don't know how much effect that would have, it would be very little space/weight to do.

 

[docnjoj]

I remember 1KW for the NuVinci 171. That 96 ft/lbs looks about right too. They do lose a lot and have efficiency at 80% or less, IIRC. What about Shimano 8 speed IGH?
otherDoc

 

[John in CR]

NV and similar CVT's does take care of some problems with electric motors.

Really? What problems? They enable you to use a smaller motor to climb steeper hills and/or go faster than it otherwise could with a fixed gearing, but there are significant compromises in terms of efficiency at cruise, and the biggest limitation on our ebikes which is space. They're just a bandaid that all of us think is a good idea early on. The truth is that if you invest that weight in a bigger motor you will get superior performance and efficiency. Trains have fixed gear electric motors, so do some very large ships, so do Tesla's after failed attempts at a 2 speed tranny with the Roadster, so do all electric racing motorcycles, so do the fastest ebikes on this forum. ICE's need multiple speed gearboxes or CVT's because their power and torque ranges are so narrow. Electric motors don't suffer from this limitation, and you really need to use your bike for 2 completely different uses to need multiple speeds. All you need is a properly sized motor. The KISS principle absolutely applies here.

This hijack has nothing to do with putting oil in a hubmotor not designed for it.

 

[macribs]

NV and similar CVT's does take care of some problems with electric motors.

Really? What problems? They enable you to use a smaller motor to climb steeper hills and/or go faster than it otherwise could with a fixed gearing, but there are significant compromises in terms of efficiency at cruise, and the biggest limitation on our ebikes which is space. They're just a bandaid that all of us think is a good idea early on. The truth is that if you invest that weight in a bigger motor you will get superior performance and efficiency. Trains have fixed gear electric motors, so do some very large ships, so do Tesla's after failed attempts at a 2 speed tranny with the Roadster, so do all electric racing motorcycles, so do the fastest ebikes on this forum. ICE's need multiple speed gearboxes or CVT's because their power and torque ranges are so narrow. Electric motors don't suffer from this limitation, and you really need to use your bike for 2 completely different uses to need multiple speeds. All you need is a properly sized motor. The KISS principle absolutely applies here.

This hijack has nothing to do with putting oil in a hubmotor not designed for it.

I rest my case your honor
Well being new to this it is too easy to draw the wrong conclusions when doing the reading. Guess I did just that once again.

 

[fellow]

What additive do you people use to prevent oil dripping thru the main bearings? I was thinking of automotive servo pump or automatic gearbox anti leaking additive (works by softening/expanding rubber seals). As I understand it, there are no rubber seals in Q100H bearings? Is there any additive that acts as a glue/thickener where the hot oil leaves the motor or something similar?

 

[bowlofsalad]

What additive do you people use to prevent oil dripping thru the main bearings? I was thinking of automotive servo pump or automatic gearbox anti leaking additive (works by softening/expanding rubber seals). As I understand it, there are no rubber seals in Q100H bearings? Is there any additive that acts as a glue/thickener where the hot oil leaves the motor or something similar?

After some lengthy discussion, we concluded that the solution to this issue seems to be putting less oil in the motor.

Something else he shared with me was a comparison of no load power consumption on a new Q100h. The stock Q100h consumed 76w at top no load speed, filled with 40ml of ATF(automatic transmission fluid) the q100h consumed 44w. Very interesting.

On an unrelated noted, is there any potential negative effects ATF can have on the gears used in geared hub motors? I've been reading what I can find on the subject and there seems to be a mix of opinion. Some say ATF isn't bad at all for plastic, some say it's bad, some say it's just heat that is bad for plastics and so on. I'd be pretty surprised if ATF did bad things to plastics, but I'd rather ask and hear what others may have to say on the subject.

 

[Marc S.]

On an unrelated noted, is there any potential negative effects ATF can have on the gears used in geared hub motors? I've been reading what I can find on the subject and there seems to be a mix of opinion. Some say ATF isn't bad at all for plastic, some say it's bad, some say it's just heat that is bad for plastics and so on. I'd be pretty surprised if ATF did bad things to plastics, but I'd rather ask and hear what others may have to say on the subject.

Well, the gears are not made from simple 'plastic', they are made from polyamide (likely Nylon 6 or 6.6) with or without glass fiber reinforcement.
Here is a chemical resistence chart of plastics as PDF http://www.professionalplastics.com/professionalplastics/ChemicalResistanceChartofPlastics.pdf
It states good resistance of Nylon 6 and Nylon 6.6 against grease and oil.

Since the Nylon gears in geared hub motors are lubricated with grease and grease is mineral oil mixed with soap to increase viscosity, it's no wonder mineral oil like ATF works pretty good without side affects... (apart from the occational drop)

 

[bowlofsalad]

On an unrelated noted, is there any potential negative effects ATF can have on the gears used in geared hub motors? I've been reading what I can find on the subject and there seems to be a mix of opinion. Some say ATF isn't bad at all for plastic, some say it's bad, some say it's just heat that is bad for plastics and so on. I'd be pretty surprised if ATF did bad things to plastics, but I'd rather ask and hear what others may have to say on the subject.

Well, the gears are not made from simple 'plastic', they are made from polyamide (likely Nylon 6 or 6.6) with or without glass fiber reinforcement.
Here is a chemical resistence chart of plastics as PDF http://www.professionalplastics.com/professionalplastics/ChemicalResistanceChartofPlastics.pdf
It states good resistance of Nylon 6 and Nylon 6.6 against grease and oil.

Since the Nylon gears in geared hub motors are lubricated with grease and grease is mineral oil mixed with soap to increase viscosity, it's no wonder mineral oil like ATF works pretty good without side affects... (apart from the occational drop)

Fascinating, thanks for the response, Mark. This chart looks great. I've read your words on these subjects of putting oil into a geared hub motor like the clergy read a bible and it's what I based my suggestion of 40ml in a Q100h on.

I said plastics (referring primarily to the types use to make gears for geared hub motors) out of an assumption that there are more than one type of materials used, can we assume all of the gears we might consider used in geared hubs are made out of nylon? I would probably ask this question to those who made a particular hub, but I am skeptical I'd be understood.

Part of what fueled this perspective on ATF effecting nylon gears relates to some marketing of 'dexron' and 'mercon'(additives or types of ATF?) being specifically more friendly to various forms of plastic.

I've been looking for an ideal fluid to put inside geared hub motors. The two top runners for me are both sold by redline(no bias or affiliation, simply the best viscosities I have found so far at various temperatures). Vis=Viscosity
http://www.redlineoil.com/product.aspx?pid=137&pcid=9 lightweight racing: Vis@100C 4.9, Vis@40C 23.2, Vis@-40C 7500
http://www.redlineoil.com/product.aspx?pid=53&pcid=9 C+:..........................Vis@100C 7.5, Vis@40C 32.3, Vis@-40C 3800

With the intention of running a small geared hub motor with a lower power limit in a climate where winters get -very- cold, I thought it might be wise to consider the viscosity of an ATF at lower temperatures. Of all the fluids I have found so far, redline C+ seems to have the best viscosity when really low temperatures are a concern. I have no idea what sort of temperatures are going to be inside of small geared hub motor when rolling down the road at 20mph when it's -10f(-23c) out with a power limit of around 300w. I've imagined simply locking the brakes and maxing out the throttle would warm things up in the motor enough if things ever got too cold, but this is only what I've imagined.

 

[macribs]

Back in my pc over clocking day we tested various ways to get the best cooling of components.
This was in the early days way before someone even thought of making large air sinks with fans.

We tried and tested everything from kitchen oils for cooking to various oil ranging from 2 stroke oil, mineral oil, ATFl and synthetic oils. While most of these worked in some way or another it was a drag and a mess to work with.

So a mate got hold of some non conductive liquid (can't remember the name but I could find out) and did a submerged pc build into a square bin and dropped his motherboard into it, placed a radiator outside his wall - this was during the cold winter in Norway so several degrees below zero for months.

This was by far the best cooling I've seen without going extreme with liquid gas. The viscose of the non conductive fluid was not as thick as most motor oils, probably something in between those extra light flow winter oils and water. Easy for pumps to circulate via radiators. Result was only a tiny condensing around the bin - solved by putting the bin into a larger bin.

We saw no degradation of motherboard, ram or any other components or wiring. Not even insulation of the wiring reacted to that non conductive liquid. It is for sale, but also expensive. But for a easy cooling of a hub motor without using big reservoir and radiator it should be no problem regarding costs.

Even for those who would like to test pumps and radiators on this non conductive liquid the cost will be doable.
As far as I know that fluid has been used to cool some ridiculous expensive hifi speakers also without impact on the magnetic fields - or the speaker "motor".

I think this would be doable, just using rubber gaskets and silicon to seal the hub. If the event of leaks down the road refill should be doable.

 

[bowlofsalad]

a mate got hold of some non conductive liquid (can't remember the name but I could find out) and did a submerged pc build into a square bin and dropped his motherboard into it, placed a radiator outside his wall - this was during the cold winter in Norway so several degrees below zero for months.

A name of a product and a product data sheet would be nice. Besides maintaining an ideal viscosity in a wide range of temperature, the fluid inside of a geared hub is also acting as a lubricant.

 

[Marc S.]

And how is your 'non conductive liquid' dealing with the various ball bearings in a geared hub motor?

I don't understand why people are so reluctant to use mineral oil for the task of lubricating a bunch of gears and ball bearings inside an electric hub motor. Its really no rocket science but pretty basic mechanics and five minutes of cross checking in Wikipedia.

-mineral oil is non conductive.
-Nylon gears are not affected by mineral oil
-ATF has all the right additives needed for the task, and then some...
-ATF keeps its viscosity over a wide temperature range
-sealings of sealed ball bearings are not affected by mineral oil

It doesn't even have do be smelly ATF. I use hydraulic oil as well. Hydraulic oil is 'spiced' with similar additives (anti foam, anti corrosive, ect) but you can obtain ATF in small quantities literally at every third corner. Heck, I even used high temperature turbine oil to fill up my hub when I worked at Airbus. (whats good enough for Rolls-Royce is good enough for Bafang!)

In the German forum somebody even used salad oil to avoid putting that terrible mineral oil in his precious hub. He ended up with some kind of majonese...

 

[nechaus]

nylon is highly resistant to many oils.. resistant to many solvents

 

[macribs]

And how is your 'non conductive liquid' dealing with the various ball bearings in a geared hub motor?

I don't understand why people are so reluctant to use mineral oil for the task of lubricating a bunch of gears and ball bearings inside an electric hub motor. Its really no rocket science but pretty basic mechanics and five minutes of cross checking in Wikipedia.

-mineral oil is non conductive.
-Nylon gears are not affected by mineral oil
-ATF has all the right additives needed for the task, and then some...
-ATF keeps its viscosity over a wide temperature range
-sealings of sealed ball bearings are not affected by mineral oil

It doesn't even have do be smelly ATF. I use hydraulic oil as well. Hydraulic oil is 'spiced' with similar additives (anti foam, anti corrosive, ect) but you can obtain ATF in small quantities literally at every third corner. Heck, I even used high temperature turbine oil to fill up my hub when I worked at Airbus. (whats good enough for Rolls-Royce is good enough for Bafang!)

In the German forum somebody even used salad oil to avoid putting that terrible mineral oil in his precious hub. He ended up with some kind of majonese...

For a geared hub motor I am not sure how it will work out. I honestly didn't even think of anything other then DD hub motors
So my thoughts on geared hubs are that oil much likely is a better solution.

As to your story if the german bloke I totally understand why someone might put salad oil into a hub motor. What I can't see is why one would add egg yolks also. (mayo)

 

[macribs]

A name of a product and a product data sheet would be nice. Besides maintaining an ideal viscosity in a wide range of temperature, the fluid inside of a geared hub is also acting as a lubricant.

I will get back to you on that. I tried a quick google search but I din't find the one, so I will need to look up some old static html websites we had way back when we did o/c. I think I got em all still, just need to find back to em.