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Need advice on creating planetary gear

Oldbelt

Senior Member
Albie interesting SW.
I have given the data: the module and amount of teeth's in the wheel's it is in the Companies part numbers. See # post 39.
Step #1 Ring Gear GPSO.5-120 GPA
sun Gear GO.5-24 PG
Planet Gear 3 piece's GO.5-48PG

Step #2 Ring Gear GPSO.5-120 GPA
sun Gear GO.5-40 PG
Planet Gear 4 piece's GO.5-40 PG
 

albie0803

Alibre Super User
Yes, I used your numbers. These are the dimensions we would use (plus backlash) if we were making the planetary sets. Note that the pinion and planetary gears in the second set have different ODs even though they have the same number of teeth.

Just providing (helpful) information if you wish to use it.

It will be interesting to see if .5M gears can be successfully 3D printed.
 

Oldbelt

Senior Member
Albie , Sorry, thank you for presentation of the SW you have bought. I can't see the sum rule being used, determining how many idler wheels there can be used.
I use the old HP15C pocket calculator I used at UNI back in the fifties.
The two wheels in the stock list from HPC gears have standard size OD = 2*M + Pitch = 2* 0.5 + 20 = 21 mm.
It looks funny in your SW, because one wheel have a +addendum the other a - addendum at top and bottom.

I think Kunstman will use this source, (HPS) 3D print in this scale (M0.5) will not be good, to my experience.
Thank you for our discussions, I have learned a lot about Planetary gears gear.
 

albie0803

Alibre Super User
I, too, have learned a great deal. We don't do much with planetary gearboxes, except for the ones we overhaul. I will look in the manual and see if it gives the reason for the oversized/undersized gear setup. It happens a lot in gearboxes for strengthening gears and for standardising or adjusting centre distances. I didn't know about the sum rule either, or the differences between driving the ring gear and driving the carrier.

It's good to get your head around something new now and then.
 

MilesH

Alibre Super User
Planetary gears are fascinating. I did a proof of concept model a while back, based on an idea that I had. It's a 2 speed gearbox that utilises the change in output torque direction between locked planet carrier mode and locked ring gear mode to change gear. Opposing pairs of sprag clutches are used to lock either the planet carrier or the ring gear based on the input torque direction. The output torque direction will stay the same but with the change in ratio. I used a 3:1 ratio of sun to ring gear so you get either a 3:1 or a 4:1 gear change simply by changing the torque direction of the input (sun gear). The output torque direction (from ring gear or planet carrier) is always the same.
 

MilesH

Alibre Super User
Hi Oldbelt,

I think you need to change the video setting to public viewing. It says "Video unavailable".
 

Oldbelt

Senior Member
Hi Miles.
I have no experience in this field, I can open it and play, but when it is finished all the video at you tube can be opened inside from the post.
Very annoying, how do you do this ,I saw you had uploaded a video some time ago,
I used you tube studio to do this.
 

GIOV

Alibre Super User
Hi Oldbeldt,
Is it feasible to attach your 1:24 planetary gear set in a STEP file since I use ADV22.
Nice design!
 

GIOV

Alibre Super User
You mean every single part in a separate step file, you can assembly.??
Yes Oldbelt, every single part in a separate step is ok for me plus if you can, a 3D PDF to know the correct assemble. Sometimes you can export the whole set in an already assembled file and then single out each part separately to study and redo.
Thanks in advance !
 

albie0803

Alibre Super User
I will look in the manual and see if it gives the reason for the oversized/undersized gear setup.
The sun gear gets oversized in order to minimise the undercutting of the tooth that can happen with gears with small numbers of teeth, The planetary gear is then undersized to suit and the planetary PCD is altered appropriately.

Pinion gears are often oversized as well to increase their lifespan as they will rotate several times faster than the bull gear. To compensate, the centre distance is adjusted or the bull gear undersized to suit.
 

Kunstmaan

Alibre Super User
I think Kunstman will use this source, (HPS) 3D print in this scale (M0.5) will not be good, to my experience.
Thank you for our discussions, I have learned a lot about Planetary gears gear.
Your correct, but I wi;l try to make a 3D printed model for demonstration purpose that wil rotate slowly. regarding this what script shpould I use to create a gear inside Alibre ??
 

Oldbelt

Senior Member
Albie, you are right I remember now from the text book that min number of teeth's is 14 if under cut shall be avoid.
GIOV
 

Attachments

  • Planetary_Gear_1_24 (1).pdf
    1.1 MB · Views: 9

Oldbelt

Senior Member
Kunstmaan.

This package contain all parts, open every single part and export them as .STL for 3-D printing.
The gear housing isn't finished you have a lot of work to do!!
Planetary Gear 1_24.JPG
 

Attachments

  • Planetary_Gear_1_24 (1).AD_PKG
    2.7 MB · Views: 9
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