Posted by Joe Johnson at 1/22/2001 8:31 PM EST
Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.
In Reply to: Re: spur gears & fishers ...newbie question...
Posted by ChrisH on 1/22/2001 2:01 PM EST:
All the gears in the F-P are pretty much standard gears
(they use a slightly modified tooth profile from
typical metal gears, one more suitable for molded
plastics, but for our purposes they mate just fine with
off the shelf metal gears). For gear heads in the
audience, they are note "enlarged" or otherwise
modified for strength or manufacturing purposes.
They are also all 20 deg. pressure angle gears.
Finally, they are all English pitch gears (not metric
module, but integer "Diametral Pitches"
.
I cannot recall all the pitches but I am pretty sure
they start at 32 DP at the motor and grow down to
something like 16 DP at the final stage.
Here is a trick to estimate the DP a standard gear:
DP = (Nteeth +2) / Outside Diameter
This works because the addendum of a standard gear is
1/DP. The Pitch Diameter is 1/Nteeth. So the OD =
Nteeth/DP + 1/DP + 1/DP Solve for DP and Viola!
Good Luck,
Joe J.