Light, fastest, climbs mountains, and pretty efficient

[Ian]

Yes, if I could move a lever to switch between the Sprinting ability of my Torq, and the Torque of my Sprint I'd be more than happy.

 

[coops]

...............

 

[flecc]

Yes, if I could move a lever to switch between the Sprinting ability of my Torq, and the Torque of my Sprint I'd be more than happy.

I understand it was US eZee dealers who first highlighted the anomaly of those names. Of course it would have been more glaringly apparent to them with the 350 watt Sprint motor but still the 250 watt Torq motor.

I'm sure eZee would have got the names the right way round if they were launching both at the same time instead of years apart. They seem quite name aware for the Orient, realising that Fury (US) wouldn't go down well here and changing it to Forza for us, including Europe.
.

 

[coops]

A very simple, neat & elegant solution flecc, just as you said . Nice work Ian I'm glad I didn't have to wait longer for the answer!

It befits the thread title too!
Now to see if anyone follows it up as you say flecc hope so!

Stuart.

 

[Ian]

I understand it was US eZee dealers who first highlighted the anomaly of those names. Of course it would have been more glaringly apparent to them with the 350 watt Sprint motor but still the 250 watt Torq motor.

To be fair to the Sprint it's no slouch and certainly not unworthy of the name, but the Torq's name could be misleading, probably being more appropriate if applied to a tractor. A more sporty name would suit, something like T-bike if it wasn't already taken

 

[flecc]

Yes Ian, initial prefixes like Q bike and T bike can work instead of a name, and Sinclair's done it with the A bike folder now. Plenty of letters left.

Thanks Stuart. I'd like to think a manufacturer would take this up, but I don't see the Chinese as very enterprising where doing things differently are concerned, unlike the Japanese who are much more receptive to new ideas.
.

 

[richard]

Well done flecc, thank you for a tantalising, tittilating conundrum.
I have been following it with great mirth and interest, however now that my little brain can now stop buzzing with whacky ideas and accept that perhaps my thinking cannot climb out of the box ! I would ask is there a way to pursue this very elegant line of thought in a practical way.
Nice one
richard

 

[flecc]

I don't really know Richard, it's Open Source so anyone can take it up.

I've been refining ways of using the epicyclic for the two gears, which is the sort of technical aspect I'm interested in, but in retirement have no interest in getting involved in commerce in any way, nor have I any interest in reward.

My main purpose in these threads is in maintaining technical items of fresh interest in the forum, basically entertainment, hence the conundrums and clues.

But if you or anyone wants to do anything with any of them, please feel free, fortune awaits!
.

 

[JohnInStockie]

Nice one Flecc.

I understand some of your proposal. Ther are 3 small cogs in the motor yes, and your saying the power should drive through them yes? But they would be different sizes to give the motor gearing, is that right?

I unfortunately am too much of a layman at these things...

John

 

[flecc]

No John, there's no change of cogs. As many people don't know it, I'll explain the content and action of a three speed hub to give understanding. Below there's a picture of the epicyclic end of a motor, and to represent a three speed hub, I want you to imagine the orbital toothed ring surrounding the orbital cogs that you see, instead of being stuck inside the hub shell:

The cog in the centre is called the Sun, the surrounding cogs are called the Planets and they are mounted in the planet cage. The toothed ring that surrounds the planet is called the Annulus.

The Sun is fixed and part of the spindle in the bike's hub. If a drive is taken to the Annulus (surrounding toothed ring), as it rotates it tows around the planet cage with the planets revolving on the fixed Sun. Obviously the planet cage travels slower, so if that is connected to the hub and therefore the wheel, it's geared down so it's bottom gear.

If we do the opposite and drive the planet cage, the annulus rotates faster around it as the planets are spun on the fixed sun. Fixing the annulus to the hub and therefore the wheel means it spins faster and is geared up, so it's top gear.

For middle gear we drive the hub and wheel direct, neither geared up nor down. And that's the way a three speed hub is made. For more gears, the usual method is another orbital set, and with the drive transferred between the various ways of driving each that can give even 7, 8 or 9 gears. A hub leading the drive between various orbital drives in that way is called a compound hub gear. The Rohloff compound hub using three orbital sets has 14 gears

From this you can see how I can use the same principles in various ways for two gears with the motor driving.
.

 

[JohnInStockie]

Thanks Flecc for putting it into laymans terms

Unfortunately, I am still struggling to envisage it. I havent had enough experience of gearing to understand this I think.

Let me give it a try...

The Sun turns the fastest, it in turn turns the planets slower, which in turn turns the Annulus even slower. So you would have 3 other cogs connected to these, is that right?

Thanks

 

[flecc]

No John, the Sun is part of the spindle, fixed to the frame, so is stationary at all times.

The three planet gears surround the sun and are engaged with it.

Around the whole is the circle of the annulus gear, it's teeth engaging with the planet gears.

Now if that annulus around the outside is rotated (by a drive from the sprocket) around the whole, the planets are forced to rotate, since they are engaged with the stationary sun, and have to roll around it.

As those planets revolve around the sun, they and the ring cage they are mounted on are trailing along after the outer annulus as it turns.

As that planet ring is travelling slower, we connect it to the wheel, so the bike wheel is now revolving slower than the sprocket. Therefore it's geared down, so that's low gear.

If we reverse that and connect the sprocket to the planets instead, turning them around, they revolve around the stationary sun again and carry the outer annulus around, this now travelling faster.

Therefore we connect the outer annulus to the bike wheel, making that revolve faster than the sprocket, therefore geared up, so it's high gear.

To understand gearing in general, think of the bike chainwheel and rear sprocket. Turn the large chainwheel once, and the small sprocket has to turn several times. That's a high gearing, gearing up for more turns out.

If you do the reverse and turn the small sprocket, you'll have to turn the sprocket several times to turn the chainwheel once, that's a low gearing, gearing down for less turns out.

Although it's more complicated to understand, that's all that's happening in an epicyclic, the sun in the middle is small, the outer annulus ring is large, so different ratios exist between them, the direction of the drive applied determining whether it's geared up or down.
.

 

[Ian]

3 Speed Hubs

Further to Fleccs comprehensive description above this page gives an excellent description and cutaway diagram of the old Sturmey Archer 3 speeds, on which others are modeled.

 

[ITSPETEINIT]

Gearing in a Hub Motor

Hello Flecc:
re your last two posts on this subject (unless you are posting another as I type).
I understand the principles of the three gears that you expound.
My question is: "How do you propose to change between one gear and another?"
Just an aside: I would hope to get a top ratio between the present Torq gearing and Sprint gearing. A low gear lower than the Sprint (I'm old and feeble and like to rest often before I reach the top of a long hill) and a high gear lower than a Torq (I don't need 23 mph - at least not at the expense of battery range).
Say, something that would climb 14% at 5 mph (unassisted) with a pay load of 125 kgs and cruise at 16 mph on the flat in high gear. Middle could be used for intermediate hills. Lots of lovely torque.
It would be a shame to lose these conclusions to an academic experiment.
Thank you Flecc
Peter

 

[Miles]

Here you go: Rohloff - How it works

 

[flecc]

To Peter

For external change control in normal hub gear fashion Peter, the spindle hollow on the opposite side to the cable (the gear side) with an actuator rod. No point in details before determining which elements to choose in the gearing. Either a rotating sun driving the planets for a lower gear, plus direct drive, or a driven free annulus driving the planet ring in hub gear fashion. The detail isn't important, it's for the final designer to decide, as are the possible mechanical and electrical change methods if used.

You won't be able to adapt those existing bike hubs to this method, the motors no good for this job. A motor near to a direct drive one, but designed for very low speed rotation being needed. There's no alternative gears available for your motors either.
.

 

[coops]

If I've understood correctly, I think that the topmost animation here somewhat illustrates the top & bottom gears in action: when engaged with the wheel, the outer ring (annulus) is the top gear when the motor drives the intermediate "planet" cogs, and vice versa the planet cogs make the low gear when engaged with the wheel while the motor drives the outer ring (annulus).

For middle gear, one must envision the hub & wheel being driven directly at an intermediate speed.

Stuart.

 

[flecc]

Yes, that's a good illustration Stuart, but it would be much easier for people to understand and follow if the animation had been smoother.
.

 

[Miles]

Just had an idea - and it will probably remain so....... but:

Supposing one had opposing overunning bearings on the carrier and the planets and that with the sun as the driver you had a negative gear ratio for low gear. For the high gear (direct drive) you would reverse the direction of the motor - the planets would lock and the carrier would be free to move - everything would move at motor speed.

Think I'll go and lie down for a bit before thinking this through again...

 

[JohnInStockie]

Ok, I think I am beginng to get it from the excellent examples that have been posted. A couple of questions though.

I understand that the Annulus and the Planets turn at different speeds, but I dont understand how that effects wheel rotation. On a deraillier its simple, you can see the chain going from the crank to the gear selected. But on internal hub gears, if I choose the Annulus gear, how does that gearing get pased through to the wheel?

Is there something else involved, something shifting back and forth across the gears that isnt shown in these diagrams?

Or am I a lost cause?

EDIT is this what the spindle is doing, and also selecting what is in contact with the wheel?