adding rev. on a CVT bike/Trike

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coachgeo
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adding rev. on a CVT bike/Trike

Post by coachgeo »

ok.... say you have CVT belt drive in place of a gear box. Drive Pulley half of CVT system; attached to crankshaft, powers the driven side Pulley of the CVT system via the belt. Driven side Pulley is attached to a jackshaft which rotates final chain drive to rear wheel. Typical set up.

What if you put an electric motor ALSO to that jackshaft. Intent would be to WHEN BIKE IS SITTING IN NEUTRAL (Drive CVT pulley wide enough to where it does not grasp the belt) you use the electric motor for reversing the bike/trike

Example

. bike/trike sitting at low RPM. Low enough to make Drive pulley of CVT system; mounted to the crankshaft of engine, change shape via low Centrifugal forces & magic components of the CVT. The pully now sits expanded enough to no longer be grasping the belt. Thus bike is sitting there essentially in neutral cause the Drive pulley is just slipping by the belt and not moving it.

. Now Power the jackshaft with electric motor IN REVERSE direction of engine... this spins the driven pulley of CVT system and its attached jack shaft (along with the chain drive to rear wheel thus moving the bike backward as desired).....

:?: ... Will the spin of the jackshaft at some point in the RPM range potentially cause a change shape of the driven pulley thus grasping the belt ?

If I understand how a CVT works; it wont cause the driven pulley only shape changes by forces tugging on the belt. Centrifugal forces do nothing to the Driven pulley. So that should answer my own question... but doubting myself when I say.... spinning the driven pulley alone will not change its shape :?:

If I'm right about that there does then lay another question

Does the driven pulley remain tightly squeezed
; thus always have a grasp onto the belt :?: for the CVT concept to work I think it has too. If so now you have reversing electric motor spinning the belt in opposite direction of the engine.

If belt does remain grasped on the Driven pulley at the jackshaft.... would it matter?.... Yes the belt is now spinning opposit direction but since the belt is NOT grasped by the front drive pulley; attached to the opposit spinning crankshaft; for reasons described previously (low RPMs expanded the pulley). Seems then no matter which way the belt it moved by the Driven/jackshaft pulley... it wont make any difference to its partner pulley mounted to the crankshaft.... the belt would slip on it and not apply any forces to it.

buttttt....... if Im wrong.... with electric REVERSING motor spinning stuff in opposite direction of engine. This means it would be bad news if the belt system tied the two together. The two power sources going in opposite direction getting linked together via the CVT belt system would mean simply Somethings gonna break.

Is my thinking right that the rev. Spinning Electric motor as described above would roll the bike/trike in reverse but do nothing to make the CVT system link the two motors together in opposition to one another?
albertaphil
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Re: adding rev. on a CVT bike/Trike

Post by albertaphil »

Coach, you are correct.

That is, at the speed that any electric motor will be spinning the jackshaft in reverse, there will be no effect on the driven pulley.

And to answer the question you didn't ask...yes, it would be much simpler to add a reverse gear to a CVT equipped bike, IF you leave yourself enough room to add the said electric motor. It sounds like a neat idea to me.

Phil
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