Planetary gear with clutch. Input/output ratio
Planetary gear with clutch. Input/output ratio
(OP)
Hello there,
Please take a look at the attached pic. The sun has 20 teeth,planets(3) have 16 teeth and the ring has 52. The planetary gear ratio(teeth no .ring/sun) is therefore 2.6 . The ring gear is the input of the driveline and the planetary carrier is the output. when the clutch is locked (see figure) The input output gear ratio(ring/planet) is supposed to be 2.6 + 1 . Could you please help me arrive at this formulation.
Please take a look at the attached pic. The sun has 20 teeth,planets(3) have 16 teeth and the ring has 52. The planetary gear ratio(teeth no .ring/sun) is therefore 2.6 . The ring gear is the input of the driveline and the planetary carrier is the output. when the clutch is locked (see figure) The input output gear ratio(ring/planet) is supposed to be 2.6 + 1 . Could you please help me arrive at this formulation.





RE: Planetary gear with clutch. Input/output ratio
The ratio is (2.6 + 1) / 2.6 = 1 + (1 / 2.6) = 1.385:1
If you figure out how many times the planets rotate in world co-ordinates during each revolution of the planet carrier, and translate that into the number of teeth that the outer ring has to advance, you can see why this is the case.
RE: Planetary gear with clutch. Input/output ratio
Your diagram appears to show the clutch element coupling the sun gear and ring gear. When the sun and ring gears are coupled, you have what is normally called a "shaft". So the input/output ratio is simply 1.0.
When the sun and ring are de-coupled, the sun gear would appear to be free spinning, thus you have an "open" gear system (ie. one that is not capable of transmitting force). So the input/output ratio becomes infinite.
Your schematic seems to be incomplete. Or maybe I'm missing something?
RE: Planetary gear with clutch. Input/output ratio
RE: Planetary gear with clutch. Input/output ratio
RE: Planetary gear with clutch. Input/output ratio
Any gain in torque through the shafts has to be matched by torque applied in the opposite direction to the stationary housing ...
RE: Planetary gear with clutch. Input/output ratio
RE: Planetary gear with clutch. Input/output ratio
Don't get too discouraged. Planetary, epicyclic and differential gearing usually confuse me too.
Regards,
Terry