planetary gear in wildfire mechanism 1

[pete3000]

I cannot figure out the proper combination for setting up assembly components as pins or static parts. Then assigning mechanism gears to simple 3 gears with 1 bar.

thx!

 

[pete3000]

any takers?

 

[mloew]

pete3000,

You did not ask a question; you only made a statement regarding your difficulty. I would suggest tying to find a tutorial that can help you. Please check the FAQ section for links that may guide you in the right direction.


Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Guest0527211403]

There are a lot of possible combinations for planetary gear sets (machinery's handbook has over 20!). Each of them is unique in its own respect as to the constraints that you would have to apply.

All I can suggest, based on your inquiry, is that you assemble the planet gears to the bar using pin connections. Then, assemble the bar/planets subassembly to the sun gear using another pin connection. Then, apply the gear connection between the outer gear (internal teeth) and the planet gears. Finally, apply the gear connection between the sun gear (external teeth) and each of the planet gears. Note here that the outer gear is fixed, the sun gear is the input, and the rotation of the bar is the output.

I am basing this description based on a very simple planetary gear assembly that I created about 6 months ago for a former professor of mine. It comprised of a central sun gear, and outer internal gear (I am aware of the irony of that statement... what I mean is a ring gear with internal teeth.. the proper name escapes me), and a "bar" linking the three planets. The setup was a mock-up of an old cordless drill he used to teach us about planetary gears.

-Mark

 

[mloew]

For more information on planetary gears I suggest consulting the Epicyclic Gear Train page at Efunda.com(

http://www.efunda.com).

The outer gear (with internal teeth) is called a ring or annulus.

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[pete3000]

THANKS! I WILL GIVE IT A TRY!

MY IDEA WAS FOR A HOME PROJECT TO TAKE A 2 RPM 12V ELECTRIC MOTOR AND GET IT DOWN TO THE ROTATION OF THE EARTH FOR A DOBSONIAN TELESCOPE. (.0014 RPM)

I WILL LET YOU KNOW HOW IT TURNS OUT.

 

[mloew]

Pete,

At that ratio, you may want to investigate Harmonic Drive Gearing.

I suggest that you make any further questions specific to gearing in the Gear & Pulley engineering Forum (forum406).



Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Guest0527211403]

Sounds like a great project. Good luck.

If all else fails, and you can't get it to work, you can just create a single gear connection between the motor axis and the telescope's rotation axis. Manually enter in the values using the "User Defined" option under the Proerties tab. There you can enter in the desired ratio of the drive. This cuts out development time if the planetary gear set is purchased anyways and has a fixed in and out ratio. You can then make separate connections for each of the planets so that they spin in unison with the rest of the assembly, but they won't have an effect on the output (that is strictly for show ).

-Mark