"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

Tracy Crook wrote:

I was very interested in the role of the rotor and stationary gears in the
Wankel engine.  The above explanation would imply that all of the torque
generated by the engine is transfered through the gears.   Don't want to get
into a long discussion but my own analysis found this not to be true.   The
gears appear to be loaded mainly by inertial loads imposed only when the
rotors change their rotational speed and by the frictional loads on the
rotors.  This of course ignores a multitude of vibrational and harmonic
loads but the main point being that the loads on these gears is normally
quite minimal.

 As a sanity check, think about the 750 HP that Able Iberia (Sp?) gets from
his 13B.  Think those little gears would reall transfer that much power?

Tracy Crook
rws@altavista.net
www.rotaryaviation.com

Right on for the most part Tracy. The gears must also deal with a slight pressure
imbalance on the face of the rotor. If the pressure across the face of the rotor
was uniform in all three chambers all force would be transferred to the e-shft 
through the eccentric. As I said some time before on here the really neat thing
about the rotary is the compression, expansion and exhaust pressure forces are
all self contained inside the rotor with no moving parts. This cannot be said
about any piston engine. Neat!!! Really trick engine!!! :-)

Paul Lamar
 
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