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View Full Version : pic: Drilled out gears

Iain McLeod
27-01-2005, 01:05
[cdm-description=photo]19774[/cdm-description]
JVN
27-01-2005, 01:09
Looks pretty good!

We're doing something similar. See attached for 229's lightening pattern.
There is a lot of weight in these gears, ripe for the picking.
The gear seen below went from .49 lbs to .21 lbs. Not shabby!
Mr. Ivey
27-01-2005, 12:51
While you may be turning your gears into swiss cheese, just hope your robot doesn't turn out the same...
ivey
Jay Trzaskos
27-01-2005, 22:22
Looks pretty good!

We're doing something similar. See attached for 229's lightening pattern.
There is a lot of weight in these gears, ripe for the picking.
The gear seen below went from .49 lbs to .21 lbs. Not shabby!
I must say this again...
John that is awesome. Great lightening pattern.
pakrat
27-01-2005, 23:06
My guess, we haven't seen the end of insane hole drilling in gears. Our team has a little something on those same lines.... ;)
dlavery
27-01-2005, 23:11
Very nice weight reduction efforts. But just remember not to be TOO aggressive about removing material - it is possible to take a good thing too far. I always like to remember this image from last year:

http://www.chiefdelphi.com/pics/bin/107940591948.jpg (http://www.chiefdelphi.com/forums/showthread.php?threadid=26803)


-dave
EricH
27-01-2005, 23:27
I'll agree with Dave. We had drive sprockets last year and took a little too much off. They broke in post season with more events to go, so we had to replace them.So I'd say that if you must lighten a gear, do it a little at a time, preferably only if you are over weight or planning to be (in which case, the robot will start looking like swiss cheese). ;)
Bharat Nain
28-01-2005, 00:21
Hey we drilled holes in our wheels to reduce weight.:p It wasnt noticable, but it worked, and they were still reliable.
Paul Copioli
28-01-2005, 07:07
FYI, Jon V-Neun consulted with me before his team modified those gears. I did a quick Finite Element Analysis and told him he could take more material off if he wanted too. The two big areas of concern are the area near the hex shaft and the area near the gear teeth.

John,

That is a really cool pattern, by the way.

A comment about Daves Picture:

The main problem in the picture is that there are only two spokes holding the sprocket to the hub. That is an unstable solution. They could have gone with 1/3 the spoke width and added a third spoke and been fine. Notice the failure mode is in the bolt twist direction. A third spoke would have made it much more rigid/stable.



-Paul
Mark McLeod
28-01-2005, 09:45
See attached for 229's lightening pattern.
There's always someone who's "Hol(e)ier than thou";)
deltacoder1020
06-02-2005, 06:41
ouch. that was bad, mark :P