Hello,

i would like to show some technologies and explain wich are Continuous variable transmission (CVT) and which are not!

At the beginning, it was the dinosaurs, and just after, the differential:


we can see that there is one rotary input and 2 rotary outputs.
I can simplify like that:


We can say: input speed = output speed 1 + output speed 2.
And input power = output power 1 + output power 2.

So if we put a brake on output 2, what do we have?

Is it a CVT between input and output 1? no! why? because some power is lost!
Input power is different than output power output 1.

A real CVT must keep power!

Now, let's see this thing (planetay gear):

It is like the differential, but the output speeds have  differents laws.
I can simplify like that:


So you understand that if I put a brake on output 2, we wont have a CVT for the same reason (power lost) than above.

And with a more complex machine like that:

The problem is still the same: if we put a brake on output 2, we will loose power!

This complex machine is shown there (without showing the brakes!!):



And it is describe there.

Into the hybrid vehicules, with 2 motors it is possible to mesh power of the 2 motors, with.......a differential (or planetay gear)!
But adding power of 2 motor doesnt make a CVT.

Well, now, look at technologies that do not lose power.

Into this category, a lot of them use friction.

The 2 cones:
We see teeth inside of the belt which may fall in front of the grooves. For this reason, the grooves are flexible.
In this case, the device works thanks to the friction.


The toroidal:


The belt well known,

and its new version the metal belt:


In the category without friction, we have:

The chain (with a comparison with others technologies):



It seems to be better. But there is a chain, my CVT has no chain!

So, we can compare the technologies and theirs disavantages:

Technology lose power
many motors
friction chain
hydraulic
electro-mechanical
low torque
with brakes
X





no
for hybrids

X



no
2 cones


X


yes
toroidal


X


yes
metal belt


X


yes
hydraulic



X
yes
chain



X

yes
electro-mechanical




X yes
Maguer CVT
No
No No No No No No

Back to my CVT description.