Is next possible pls : planetary gear system with -- fixed sun gear -- 2, 3 or 4 planetary gears ( which is possible ?? ) so that output speed of ring gear is exactly 2x speed of planetary system ? I mean : for 1 revolution of the planetary "holder", the ring makes exactly 2 revolutions. As the planetary system is the drive, the ring system is driven. The result is in the same direction, if I understand this correct.
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$\begingroup$ Can't draw it, but would 2 planetary system working together work ie the outer (sun) then drives a second cage with a different diameter planet and separate second output. $\endgroup$– Solar MikeCommented Aug 6, 2017 at 7:48
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$\begingroup$ Your system is very non-standard. Usually the ring gear is fixed, and sun + carrier are input and output. This would allow such gear ratio. In more rare cases sun and ring are input and output, with ring fixed (this reverses the direction). Fixed sun and moving ring+carrier is a setup I have yet to encounter in practical use. $\endgroup$– SF.Commented Aug 6, 2017 at 9:45
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$\begingroup$ @ enterpreneur : thanks, ok if not possible @ SF : what would be the n° of teeth required for the different gears when the ring gear is fixed ? This could give me the possibility to search if a ready-made set is available on the market. I do have a solution if (as you said) the resultant direction is reversed, to reverse the direction again on a 1 on 1 basis & on the same axis/axle. $\endgroup$– johnnyCommented Aug 6, 2017 at 13:57
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1$\begingroup$ Only commenting is not enough, edit it into your question. $\endgroup$– peterhCommented Aug 6, 2017 at 18:34
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It does not appear possible. When the planetary holder rotates 1 time the ring gear rotates 1 full time plus the number of teeth on the sun gear. So in order for the ring gear to rotate twice as many times the ring gear and sun gear would need to have the same number of teeth. So in that design it would not be possible.
If however the planetary holder is fixed then the ratio between the ring gear and the sun gear is simply the ratio of the diameters. For example a 1" sun gear and a 2" ring gear would provide a 2-to-1 ratio. This would not take advantage of the planetary action, and likely could be achieved without the planetary carrier.
