Planetary gearbox backlash calculation

[sandeshg]

thread406-315223

Hi, I am facing an issue while calculating a backlash for a planetary gearbox system.

My design is, ring gear fixed, sun gear rotating & output is given by planetary system.
I could calculate the backlash in between sun-planet & planet-ring gear.

But I do not know whether I need to add backlash of all the gear stages to calculate the backlash of whole gearbox or not.

Please guide.

Thanks & Regards,
Sandesh

 

[mfgenggear]

Where did this requirement come from. Most ligature specifies the backlash is based on the diametral pitch or mod and pressure angle.to prevent jamming and interference.

 

[sandeshg]

Requirement is for a gearbox in a medical application wherein backlash is critical.I could find some literature to calculate the backlash for a spur compound gear train. but not for a planetary gearbox. Hence, looking for a guidance here.

Thanks,
Sandesh

 

[mfgenggear]

Critical is not a requirement please explain the function. In a critical application the gears are Precision ground. And held to very close tolerance and thus less or minimal vibration. Gear trains must have backlash as I said before. Not enough back lash will cause interference. And could cause damage to the gears. Please provide a snip of the white paper on this issue.thank you

 

[mfgenggear]

Back lash is controlled by center distance, pitch diameter of gears, tooth thicknes. The desired back lash is required by diametral pitch and pressure angle. .the tooth thicknes. Is controlled by measurement over wires. Or base pitch.

 

[Mechtex9879]

Hello sandeshg

In order to calculate the backlash of whole gearbox you need to calculate the backlash for each individual gear mesh in your gearbox.

Since you have a planetary gearbox with the ring gear fixed and the sun gear rotating, the output is given by the planetary system. The backlash between the sun-planet and planet-ring gear meshes will affect the overall backlash of the gearbox.

To find the total backlash of the gearbox, simply add up the backlash values from each gear mesh. In your case, you would add the backlash between the sun-planet and planet-ring gear meshes.

Thank You