Can someone help me calculate the gearmesh frequencies and 1X of the gears with the following configuration:

Annulus (Ring Gear) 129 Teeth
Planetary Gear 39 Teeth
Sun Gear 51 Teeth

The annulus is the primary driver and turns at 1796 RPM counter clockwise. The planet gear turns clockwise. The planet carrier is the secondary driver and turns 200 RPM counter clockwise. The sun is the output and turns 5000 RPM counter clockwise.

I have some formulas but nothing is making sense.

Can anyone help?

Jeremy, something doesn't seem to be correct. You state that the annulus and sun both turn the same direction which would make this a true "planetary" arrangement, as opposed to a "star" or "solar" arrangement. The overall ratio of a planetary arrangement is (Nr/Ns)+1 = (129/51)+1 = 3.529. However, 1796*3.529 = 6338 RPM, not the 5000 you state.

Are you sure of the tooth combination, etc.? Review the attached for a pictorial of the arrangements.

Epicyclic_Arrangements.pdf (167 KB, 78 downloads) Epicyclic Arrangements

John-
Yes, you are correct. It should be as follows:

The annulus is the primary driver and turns at 1796 RPM clockwise. The planet gear turns clockwise. The planet carrier is the secondary driver and turns 200 RPM counter clockwise. The sun is the output and turns 5000 RPM counter clockwise.

Does this make more sense?

I do want to emphasize that there are two drivers in the gear set. The annulus and the carrier are both attached to shafts that turn this configuration.

Jeremy
the sun turns clockwise with 4895.76 RPM, with two inputs.

Ricardo Góz from Brazil

Jeremy, can you post a cross section of this gearbox? As you mention, it appears as if this is a multi-stage gearbox but something is still bothering me. In addition Ricardo Goz has posted a comment about speed and direction of rotation (which diagrees with your comments).

Thanks for the help.

John-

I think my speeds may be off. I think at an output of 5000 RPM, the planet carrier turns about 130 RPM.

I am attaching a document that shows how this machine works - specifically the 2 stage planetary gearbox.

PS- I don't normally go to this extent with drawing machinery, but I needed this level of detail for our trainers to use, so I killed two birds with one stone.

Jeremy

Vorecon.pdf (202 KB, 51 downloads) Drawing of Planetary Gear Set

The previous drawing had some arrows pointing the wrong direction.

Please review the new drawing.

The description was correct.

Thanks.

Vorecon2.pdf (202 KB, 63 downloads)

Jeremy
You has a beautfull planetary. What .pdf is righ? Vorecom or Vorecon2. The input power is CCW or CW?
There is some thing in annulus of fixed planetary? There is possibility of second carrier will zero rotation?

Ricardo Góz from Brazil

Hello John from PA regards

Hi Jeremy , i would contact Voith for any info on this unit ( dont forget it is a variable speed also ) . This should be your first port of call .

Hi Dave-
I have contacted Voith and they have been helpful.

I have not been able to calculate the gearmeshing frequency of the revolving planetary gearset with the formulas they provided.

Ricardo-
Vorecon2 is the correct attachment.

All rotation directions are as if viewd from the output coupling looking back towards the motor. Non-traditional. Thus input is CW.

There is only one carrier - on the revolving planetary. In stage 1 operation, it is held at 0 RPM or allowed to slightly retard - so as not to overspeed.

Jeremy, is that an "RW" or an "RWE" drive?

John-
This is an RW type.

Jeremy, the RW drive, being a complex epicyclic, is an interesting drive. As a point of interest, the planetary gear train is believed to be one of the oldest forms of complex gearing, first appearing in China around 2600 BC, in a device referred to as the south pointing chariot. The date is often disputed although drawing several thousand years old have been found and enabled the British Museum to make a working model. The south pointing chariot was a cart with a figure on top and an outstretched arm that in theory always pointed south, regardless of turns. In modern days it was shown by a British researcher that the device, from a practical standpoint probably didn't work well. Google "south pointing chariot" for more information.

Anyway, I have attached a document I prepared on your drive. I suggest you print it in color so you can follow for a better understanding. I have used a better pictorial of the RW drive than what you supplied but I make reference to your original documents. I do not profess that my analysis is spot on as I've been away from gearing for 25 years and even then wasn't an expert on epicyclic arrangements, which can be quite complex. In addition I have used a spreadsheet (source unknown) to calculate the frequencies. It is also attached but in a separate response to the thread.

voith_drive_analysis.pdf (145 KB, 46 downloads) Voith drive analysis

Spreadsheet attached

gear_frequency.xls (28 KB, 40 downloads) spreadsheet

John-
Thanks so much for all of your help. It was much more than anyone could ask for and I really appreciate it.

One more question. (Ughh)

Since this is a variable speed drive - varied by the output from the planet carrier of the revolving planetary gearset, how can I modify the formula you provided to adjust for carrier speed?

My whole premise for questioning is that I have frequencies in my data that appear to be GMF, but could be bearing frequencies.

In parallel, I have been working with Voith. They are helpful, but, like you, I want to learn to fish - not just eat a fish.

Again, Thanks!

In my last pdf I had stated "There are attainable intermediate speeds acquired by allowing the fixed gear set sun gear to
rotate. That is best analyzed by using a procedure similar to that shown at
http://www.roymech.co.uk/Usefu...pi_cyclic_gears.html or going back to Voith. That still would be your best bet.