|View single post by Bernd|
|Posted: Fri Jul 26th, 2013 11:53 am||
|First a lesson on gearing. I worked for a major gear manufacturer that is known world wide. I worked with process engineers developing correct settings for machines in the field to produce the known hypoid gears used in rear wheel drive cars and then on hobbing machines that cut the spur/helical gearing for front wheel drive cars.
With that said I think it qualifies me to point this out about gearing. Spur gears almost have no friction. The teeth do not slide across surface face. They actually roll. The helical gear has a sliding effect as it transmitts power from one tooth to the next. The hypoid ring and pinion in your rear wheel drive cars has the highest friction do to a sliding motion as it transmits power from the pinion to the ring gear. And the worst for friction would be the worm and wheel.
Spur gears - http://images.yourdictionary.com/spur-gear
Helical gears - http://science.howstuffworks.com/transport/engines-equipment/gear3.htm
Hypoid gears - http://commons.wikimedia.org/wiki/File:Hypoid_gear.jpg
Worm and wheel - http://science.howstuffworks.com/transport/engines-equipment/gear5.htm
I've list the above gearing in order of friction.
Adding more gears in a spur gear reduction box will add friction on each bearing surface of the shaft, true, but the reduction gearing also creates more torque at the output shaft from a small motor running a high rpm at the input shaft.
If you have 8½ minuets watch my video on an R/C crane I modified.
Near the end of the video show the motions of the crane using the radio controls. The movie has been speed up by a factor of 2 so those of you that get bored won't fall asleep. All three motors used are high reduction. And I'm using one of David T's (DelTang) receivers. This was the first conversion of such a kit that I did and was not quite as smooth as I had hoped for.
That's it for my gearing lesson. Oh and the company I worked for was Gleason Works. They're on the net if you want to check them out.
@ oztrains, I've seen the video and that's on of the two the has inspired me to "want" to build a diorama depicting these monsters un-loading a ship. Thanks for the thought that they may be 3'6" gauge. Could also be 3' gauge come to think of it.
Last edited on Fri Jul 26th, 2013 11:54 am by Bernd