"Rogers, Bob J." wrote:

I was always under the impression that the eccentric shaft rotated three (3)
times for every 360 degree turn of the rotor.  That would be a ratio of 3:1
not 3:2

Me too. That is why I am confused when Mazda says it is 3:2
I think it has to do with the fact that the rotor is also rotating
and one rotor face completes 360 degrees while the shaft rotates
three times. The gear ratios is still 3:2 as there would not
be enough room around the e-shaft for a stationary gear that
was roughly only 1.16 inches in diameter. That is the stationary gear size
required if the gear ratio was really 3:1. The pitch diameter of the rotor
gear is about 3-1/2 inches in diameter. The main bearing alone on
the e-shaft is about 1.7 inches in diameter.

vance wrote:

The Ratio between the teeth count is undoubtedly 3 to 2, and this action
is not unlike differential tooth count gearing - ie the rotor makes
1/3rd turn (the difference in number of teeth) for each trip around the
stationary gear - while the geometric center of the rotor describes a
full turn driving the eccentric. In the previous discussion about rotor
torque - the stationary gear teeth act as lever points while the torque
on the rotor sort of pries the eccentric around. - Vance

If nothing else the Wankel is hard to explain is it not ? :-)

Paul Lamar
 
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