| Author |
Message |
    
ralph hampton
Registered
Username: Rhfurniture
Post Number: 39
Registered: 08-2006
| | Posted on Tuesday, February 06, 2007 - 09:39 am: | 
|
Thinking of earlierthreads, I wonder what their planetary gearboxes are like.
http://motioncontrolproducts.co.uk/index.php/cPath/27_28 |
Gerald_D
Registered
Username: Gerald_d
Post Number: 820
Registered: 11-2005
| | Posted on Tuesday, February 06, 2007 - 12:09 pm: |
|
Ralph had posted that message in the Drivers > Motion Control Products Ltd. (Bournemouth - England) thread before, but it deserves a thread of its own.
We need to understand what 5 arcmin of backlash will mean to a 25mm [1.0"] pinion on a rack....
A full turn (360 degrees) will cause a travel of 78mm [3.1"]. There are 360 degrees x 60minutes in a full circle = 21600 minutes. If 5 of these minutes are rattling loose, then that equals..
5 ÷ 21600 X 78mm are loose = 0.018mm [0.0007"]
...which is okay for a CNC router. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 821
Registered: 11-2005
| | Posted on Tuesday, February 06, 2007 - 02:55 pm: |
|
When folk mischievously want to show how bad their competition's gearboxes are, they will talk of the backlash on the input shaft. That 216:1 gearbox with 15 Arcmin on the output will have 3240 Arcmin backlash on the input, which is about 54 degrees movement of the input shaft, but still only a tiny amount on the output shaft. |
Driving Mechanisms: Rack/pinion, gears, screws & chains