Involute Gear Design Question

Machine Shop
#1

I have been working on a project where I need to design some non-standard involute gears and have run into some issues.

I can get a good involute gear profile generated but I am really having issues understanding how profile offset works and what the profile offset coefficient really means.

I have come to the end of my Google Fu but anyone’s input would be greatly appreciated.

Here is some of what I have found online:




http://www.gearcalc.com/downloads/manual/manualse48.html
http://lcamtuf.coredump.cx/gcnc/ch6/
http://www.tribology-abc.com/calculators/e2_6b.htm

#2

Pull up the machinery handbook and watch some of Tubalcains “mrpete222” videos on the subject. He does a great job on explanations.

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#3

Once you get past involute gear design it’s all eye-of-newt and arcana. With terms power and magic like: Pressure Face Angles whose simple concepts lures the unwary to design non-standard gears.

Cogs, sprockets, and chains my friend.

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#4

Definitely one of the more useful sources I have found.

I think I have that part of gear design squared away:

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So far everything I have designed is fully parametric:

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#5

Gears and bearings. Very simple looking but incredible engineering concepts behind them. Tremendous localized loads. The fact they wear so long is amazing - precise materials and machining to achieve alignments and fit. Very small differences in a lot of variables lead to premature failure. Yet, they are so cheap they commodity parts. Truly amazing.

I’m not much help here. I hated inspecting some of the gears in jet engines, really weird geometries, very high precision and surface finished that were like mirrors. Good, very specialized area of design.

Edit: And modern lubricants that effectively can keep them from actually touching so they don’t wear.

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#6

Walter taught a class on gear making/cutting.
Chased down that term “involute curves” and ran across some really interesting trig equations.

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#7

14.5 & 22 are the most common.

I’m looking forward to cutting gears hopefully soon.

#8

Memory jog
I posted this shortly after Walter’s gear class:

655 pgs of everything, and then some, you ever wanted/needed to know about gears.
Comes at a price:
https://www.amazon.com/Dudleys-Handbook-Practical-Design-Manufacture/dp/1498753108/ref=sr_1_1?s=books&ie=UTF8&qid=1517413926&sr=1-1&keywords=Dudley’s+Handbook+of+Practical+Gear+Design+and+Manufacture
Easy bedtime reading…

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