New transmission idea

[shankster]

hey guys , I'm in the process of building my own kart from scratch similar to the two seater shown on this site. I was trying to choose between live and dead axles and i came up with this idea. it would be the same wheel/axle setup as a dead axle configuration. however, both rear wheels would have their own sprocket connected to them and a chain that runs to a centrifugal clutch. the two clutches would be mounted on a 5/8" shaft that is held to the frame with some bearings. this shaft would then be directly driven by my engine, a 6.5 hp honda clone.

If I am correct, this setup would power both drive wheels, allow each to spin independently on turns, keep the engine's weight in the center of the kart, and hopefully perform well on dirt and road.

the only problems i think could be the clutches wearing down quickly because they would turn at different speeds and essentially have to act as the differential. I don't know exactly how centrifugal clutches work so I'm not sure if this would happen.

I posted an attachment of a diagram of this if its confusing. if it is still confusing let me know.

Thanks!

 

[Doc Sprocket]

Once the clutches reach lockup RPM, I don't thinks they'd be willing to slip much for cornering. A wee bit complex where a standard differential would work. But hey- if you want to build it as a proof-of-concept, go for it!

 

[fowler]

i guess u are working on the princable of one wheel speeding up when coming around a corner and thereby beating the rmp given off by the clutch

it would work but why bother

a live axle works fine for most of us and that setup would only work in a realy tight corner where the differants in speeds from each side is big enough to disengauge on clutch

my guess is most of the time u would get clutch slip and twisting of the jack shaft from the continous on and off the power from each side


EDIT
dam u TC beat me too it


to sum up
good idea
but not nesserery or realy practical

 

[Bluethunder3320]

it would work around turns, when you arent pressing the gas. the clutches wouldnt be engaged and youd be able to steer well.

your steering would be worse when you press the gas again.

 

[Doc Sprocket]

I guess u are working on the princable of one wheel speeding up when coming around a corner and thereby beating the rmp given off by the clutch

Only a one-way (or "overrun") clutch would allow that.

it would work but why bother

I don't think it would work all that well, but there is definitely something to be said for experimentation.

that setup would only work in a realy tight corner where the differants in speeds from each side is big enough to disengauge on clutch

At low speed, perhaps. Above lockup speed, I doubt it.



EDIT

dam u TC beat me too it

Me? TC?


@Bluethunder- I think there might be a desirable result ONLY if you get off the gas a couple seconds before entering the turn- the engine would need a while to spin down below lockup speed.

 

[shankster]

alrite. i was afraid the clutches would lock up and not work too well. i guess ill keep experimenting and see where good ol engineering brings me next. thanks for the help!

 

[Doc Sprocket]

Hey, no problem! Like I said, if you want to build it as a proof-of-concept, go for it! Just because some of us doubt it doesn't mean anything. He//, you could prove us wrong! But if it's just differential action you're after, just source a diff off an old lawn tractor or something, and save yourself the headaches (and money).

 

[oldbikerarlo]

Use one clucth on the engine and one way bearings in the drive sprockets on the jackshaft.

 

[Doc Sprocket]

That would work- just need a good source for suitable bearings. The only liability I can think of is a complete lack of engine braking- which probably isn't all that critical on a (non-shifter) kart. Might even increase fuel efficiency by allowing true coasting.

 

[shankster]

Use one clucth on the engine and one way bearings in the drive sprockets on the jackshaft.

that sounds great and I'd be willing to try it. any sources for finding these one way bearings?

 

[shankster]

That would work- just need a good source for suitable bearings. The only liability I can think of is a complete lack of engine braking- which probably isn't all that critical on a (non-shifter) kart. Might even increase fuel efficiency by allowing true coasting.

I'm just getting into karting so i must ask, Why is engine braking important?

 

[oldbikerarlo]

that sounds great and I'd be willing to try it. any sources for finding these one way bearings?

McMaster Car has them. they are listed under locking bearings

 

[fowler]

sorry toyustory i ment TS

the one way bearing thing sounds like a good idea

 

[#28 FASTGRASS]

sorry toyustory i ment TS

the one way bearing thing sounds like a good idea

Me thinks they are called a spragg? clutch.....

 

[Doc Sprocket]

I'm just getting into karting so i must ask, Why is engine braking important?

Depends on your driving style, conditions, and terrain. Engine braking is entirely unimportant for some. I kind of enjoy it, I supposed it dates back to my 4x4 days.