Tav + high / low trans concept

[chancer]

Read through this:
http://www.diygokarts.com/vb/showthread.php?t=28502&page=3
Actually two speed minibike.
Here is the part:
http://www.diygokarts.com/vb/showthread.php?t=28502&page=3
I personally do not understand it. LOL. But this is how it is possible.

 

[mckutzy]

Here's one I found, which appears to be a two speed setup using 2 regular cent clutches,( im guessing) with using custom spring rates, to control engagement points. Still need a spragg clutch bearing, depending on the tooth count, could be an interesting final ratio.
Plausible???

https://www.reddit.com/r/minibikes/comments/2hnuut/two_speed_jackshaft_awesome/

 

[chancer]

That is cool. Check out that Mount, and the way the exhaust pipe weaves through there.

 

[mckutzy]

I know eh......
If you have a few various choices of springs for the secondary clutch and sizes of sprockets that fit to the spragg clutch sprocket. you could have a good range of gear selections.

I see in this rendition, the critical part is the spragg clutch bearing.

 

[bob58o]

Thanks for all input!!! I've kinda "switched gears" (sorry that was bad). My mind jumps around and I ramble.

"This is off Topic" *Kinda but still in the same category. Didn't want to start a new thread, as i already mentioned this in my build log too.

I was more recently considering a different set up, something more specific to my build. Two 212s, two 30series TCs, two axle sprockets.

The TCs would be set up like normal, using the backplates. The TC sprockets connecting to the two Axle sprockets via #41 chain.

the more i thought about syncing the throttles, and connecting the jackshafts (meaning using one proper jackshaft instead of the two individual ones in the backplates), the less important it seemed to become. It would seem the variability in the TC helps here.

The speed the axle spins at will control the rate at which both of the driven units spin. Those Pulleys will have the same diameter as each other (determined by the axle rotations, via chain linkage).

If the engine RPMs differ from each other, then the two DRIVE Pulleys will have different Diameters from each other. BUT I dont think thats a bad thing either.

If one engine is at 3200 RPM, Its DRIVE Pulley is at its widest.
If the other is at 2400 RPM, Its DRIVE Pulley is at its narrowest.
The two DRIVEN Pulleys will have same Diameter.

So I was thinking...

Torque from Engine A * (TAV A Ratio) * (Sprocket Ratio)
Plus
Torque from Engine B * (TAV B Ratio) * (Sprocket Ratio)

Combine to spin the live axle

I dont think it should matter if TAV A Ratio does not equal TAV B Ratio exactly. I was probably stretching when imagining delaying one engine on purpose to stay in a lower gear longer.

Thanks again.

 

[itsid]

...

If one engine is at 3200 RPM, Its DRIVE Pulley is at its widest.
If the other is at 2400 RPM, Its DRIVE Pulley is at its narrowest.
The two DRIVEN Pulleys will have same Diameter.
....

No, the two driven pulleys will NOT have the same diameter;
that is determined by the differential force of the drive belt, not the rate of rotation..

so even if they spin at the same rate, that tells you nothing about their diameter.
(remove one belt, and that pulley will always be at is biggest diameter)

and because of that both belts will be in good tension to transmit power, and the slower turning engine will shred the belt (well.. the 'too fast' turning driven pulley will)

'sid

 

[bob58o]

that is determined by the differential force of the drive belt, not the rate of rotation..

so even if they spin at the same rate, that tells you nothing about their diameter.
(remove one belt, and that pulley will always be at is biggest diameter)

and because of that both belts will be in good tension to transmit power, and the slower turning engine will shred the belt (well.. the 'too fast' turning driven pulley will)

'sid

I think this is what I was misunderstanding from before.

So even with a set up with both DRIVENs on a proper jackshaft, then the driven Pulleys could still have different diameters if engines were at different speeds.

For it to work... Engines and throttles would have to be synced as close to exact as possible (in order to keep the TAV ratios almost identical).


I thought that may be an issue, so I also Considered two engines turning a proper jackshaft (Jackshaft 1) via chain linkage (1:1 ratio or so)

Also On Jackshaft 1 would be a single Drive Pulley from a 40Series.

Another Jackshaft, Jackshaft 2 would hold the Driven Pulley from a 40series.

A Heavy duty chain would connect the Axle to Jackshaft 2.

Chains from each engine to Jack shaft 1 will keep enfgine RPMS in sync????

Would I also need two C Clutches as well?? Not sure how trying to start one engine would work, as pulling one recoil starter, would spin the crank, the jackshaft, and the other engine's crank as well.


One Pull, two starts??? or a need for two, at least one, C Clutches???

This set up would be more complicated and expensive to build, but may work better if the 40 series could handle the power from the two 212s

May be getting into the non-economically practical range if I need two clutches as well as the TC, but heck, now I want to try something fairly original and make momma proud

Thanks
Bob

 

[ezcome-ezgo]

Why would starting the engine turn the jackshaft if there is a "drive" pulley on it? Technically these pulleys do not engage until a specific engine RPM is achieved. I believe Sir, you are over-thinking this.

 

[bob58o]

More crude MS Paint Design

 

[bob58o]

Why would starting the engine turn the jackshaft if there is a "drive" pulley on it? Technically these pulleys do not engage until a specific engine RPM is achieved. I believe Sir, you are over-thinking this.

I was thinking having both engine crankshafts connected via direct drive to the jackshaft. Crank 1 would turn, the jackshaft would turn, the drive pulley would turn, engine two crank would turn. I would only see the "clutch engagement action" on the otherside of that first jackshaft, no??

 

[bob58o]

I wasn't worried about it with the prior idea in the pic included, but to keep engine RPMs is sync, (maybe the throttle alone can do it well enough), I'm considering using the jackshaft/chains to ensure the engines are spinning at same RPM

 

[bob58o]

Maybe a single larger carb, if intake manifold can be made, but that's maybe for phase 3 lol


And if the engines are connected through chain/jackshaft w/o clutches, maybe I could set the timing so they were 180* off from each other.?????

With clutches, I've read "Self Syncing"???

 

[bob58o]

Read through this:

I personally do not understand it. LOL. But this is how it is possible.

If I keep looking, reading, thinking, and repeating.....
sometimes I convince myself I understand things that I really don't

This was helpful..
Now I see what was mentioned before about the multiple C Clutches instead of a gear selector.
Replacing the manual shifting idea with auto shifting set by the varying the springs in the clutches or by using a JS to reduce speed of one of them.

It almost seems too simple, so im sure im missing something. Ill read through again after work.

Ill have to look into how clutches work too. I assume that engagement/disengagement is just essentially connecting / un-connecting the shaft from the sprocket.

While The Low Gear C Clutch is engaged, but before the High Gear CC is engaged....

Can the LowGear CC sprocket turn the chain and the low gear axle sprocket,
which turns the Axle.
The axle has another smaller sprocket on it. The High Gear Axle Sprocket. It will turn as well, while in low gear, along with the chain and High Gear C Clutch Sprocket it is connected to.
The High Gear C Clutch Sprocket will be disconnect from the shaft (by the design of the Clutch)

At higher RPM, both clutches will be locked up.
The power will get transferred through the High Gear Clutch / Axle Sprocket ???
even though the Low Gear Clutch is still fully engaged????

 

[bob58o]

l love paint

 

[chancer]

Does any one else feel like they are trapped in someone elses mind reading their thoughts?

Or is it just me?

 

[bob58o]

Does any one else feel like they are trapped in someone elses mind reading their thoughts?

Or is it just me?

Lol I ramble. And thoughts jump around. Writing out my thoughts and drawing pics help me understand things better

 

[bob58o]

Here's one I found, which appears to be a two speed setup using 2 regular cent clutches,( im guessing) with using custom spring rates, to control engagement points. Still need a spragg clutch bearing, depending on the tooth count, could be an interesting final ratio.
Plausible???

https://www.reddit.com/r/minibikes/comments/2hnuut/two_speed_jackshaft_awesome/

Spragg Clutch is what I was missing I think. Thank you

 

[mckutzy]

Yes, that is what allows the hi and low speeds to differentiate from the clutches, for the final drive ratio.

 

[chancer]

Lol I ramble. And thoughts jump around. Writing out my thoughts and drawing pics help me understand things better

OOPS. I just realized I forgot the smiley. I was joking. Without the dreamers nothing would ever change. So Carry on!

Oh and

 

[bob58o]

http://www.parduebrothers.com/minibike/twospeedminibiketransmission.pdf

after some digging, I found this in the links I was provided. Its a nice diagram with explanations of Neutral High and Low. Now Ill try to wrap my head around this idea of a one-way clutch and how it works.

Thanks again, and stay tuned for the next episode of Insane Thoughts from a Shameless Man,

If you should feel trapped inside my head again, just click your heels three times, take the blue pill, and climb the beanstalk. My assistant should be able to help you from there.