Epicyclic Gear with 2 row of planet gear 1

[ojune0]

How can I control a misalignment when designing a shaft-system with 3set of double-row planet gear?

Input gear : planetary carrier
Output gear: sun gear




side view)
+---p p
l -----
input->--l SUN------>output
l -----
+---p p

 

[diskullman]

How about a pilot bearing


Russell Giuliano

 

[ojune0]

I'm sorry I didn't know about it?

What is pilot bearing?

And how can I apply it?

 

[cgelang]

ojune0,

Try to to use planet gear carrier on your planet gear that coupled to the sun gear, and use annulus(interanl gear that mate to your planet gear), I think these would help control the alignment.

You can vew the link:

http://en.wikipedia.org/wiki/Epicyclic_gearing

Hope these helps. Thanks

 

[JCJackson]

I assume 1 sun gear is fixed and o/all ratio is large. If this is the case, consider a propriety "harmonic" reducer. Correction of gears to achieve centre distance undermines tooth integrity too much especially if loads are large. I have had experience of just such a problematic drive which we eventually redesgned as a double worm reducer.
If miss-alignment is unavoidable and loads are not too high, consuder tooth crowning.

 

[Matt51]

I would assume this is a speed increaser, with carrier input, sun gear output, and fixed ring gear. If possible, use a common ring gear for all three stages, this helps alignment of the overall system. The input carriers are supported by bearings. The first carrier should be mounted on bearings, the last sun gear should be mounted on bearings, and in between the two carrier/sun gear assemblies can be allowed to "float" radially. This assumes at least three planet gears per stage.

 

[ojune0]

Thanks for every answers.

Actually I am designing gearbox for wind turbine.

And I intend to make 2-stage planetary and 1-helical gears.

1st planetarty stage takes very high torque so I thought double row planetary gear would be good.

But I didn't get "float" meaning. And How can I do that?

 

[Matt51]

To achieve load sharing in a planetary, often either, or both, the sun and ring gear are allowed to freely move radially. For example, the ring gear can be mounted on a splined connection, which is then connected to ground.
In two stages of planetary gearing, if the carrier of one stage is radially positioned by the sun and ring gear, and in the next stage, if the sun gear is located by the planet gears, you need no radial restraint of the sun/carrier connecting shaft. That is what I meant by "float".
I have been getting a real itch to design a 20 kW wind turbine, and have started designing one. Maybe eng-tips needs a wind turbine forum.

 

[tbuelna]

The biggest problem with planet gears is typically due to the torsional wind-up in the planet carrier structure causing axial misalignment at the gear meshes. Highly loaded planet gears normally employ spherical roller bearings, a flexible attachment for the ring gear, a floating sun gear, or a combination of all three to address this deflection issue.

Timken also now offers a flexible pin design for mounting planet gears that addresses this issue, so that the planets load share nicely:

http://www.timken.com/en-us/product...ist/Pages/TimkenIntegratedFlexpinBearing.aspx

Good luck.