Gears has different shape of teeth.
Gears has different shape of teeth.
(OP)
HI,
Please check the attachment. Those gears has different shape of teeth. They are supr gear. Want to know what is the different in performance on those different teeth?
Please check the attachment. Those gears has different shape of teeth. They are supr gear. Want to know what is the different in performance on those different teeth?





RE: Gears has different shape of teeth.
I have to assume the second is a follower. It would have weaker teeth than the standard gear but may run quieter in mesh. It looks like a very short addendum gear where the cutter is sunk deeper to form these teeth and the gear o.d. blank is reduced accordingly.
RE: Gears has different shape of teeth.
Don
Kansas City
RE: Gears has different shape of teeth.
A or B is smoother and quieter?
A or B is stronger?
A or B has larger pressure angles?
Thanks
RE: Gears has different shape of teeth.
However, these same type of gears could be produced using standard 20 degree pressure angle cutters but create that type of profiled looking gear by withholding the cutter to produce a gear looking like A. By sinking the same cutter deeper, you can produce a gear looking like B.
Normally smaller pressure angle produce quieter gears assuming no modifications are made to their mating gears.
But by using a gear shaped like A as the driver and like B as the follower or driven gear, they may be a very quiet operating gear set and this type of gearing would be called recess action gearing and have very little approach action in their mesh. This type of gearing used to be called long and short addendum gearing. The long addendum gear would be the driving gear.
RE: Gears has different shape of teeth.
RE: Gears has different shape of teeth.
RE: Gears has different shape of teeth.
The second pinion looks like it is undercut, which means it is a poorly designed involute gear, or it could be a correctly designed non-involute tooth form. The tooth thickness at the bottom portion of the tooth appears to be smaller than the tooth thickness at the pitch diameter. Look at the tooth at the 12:30 position, the first tooth to the right of the tooth at top dead center.
It is a sixteen tooth pinion, which is not enough for a 14.5 degree pressure angle system, which ususally needs at least 25-30 teeth. So my guess is you have a cycloidal tooth, which is sometimes used in gear pumps.
Take the parts to a gear shop, they can do an involute trace, and determine what type of gear teeth you have.
The pressure angle you select is directly tied to the minimum number of teeth selected for the pinion. The higher the pressure angle, the fewer the number of teeth you can use. You can't use any of the 14.5, 20,or 25 degree involute cutters, and have negative cutter shift to the extent shown, on a 16 tooth pinion, without having excessive undercut.
RE: Gears has different shape of teeth.
RE: Gears has different shape of teeth.
The gears look like 20 tooth and 24 tooth respectively.
I have a feeling these are only illustrations from a book illustrating different gear designs. I agree the second
does look like a cycloidal tooth form. I have never designed a spur gear with a 2.0 contact ratio. Interesting.
RE: Gears has different shape of teeth.
M
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Dr Michael F Platten
RE: Gears has different shape of teeth.
A spur gear always has the problem it can only be optimized for one load, usually the maximum load. A helical gear is somewhat more flexible, if a corner modification is used, part of the profile can be left unmodified.
Designing for a contact ratio of just under 2.0 has the advantage you can still use AGMA rating standards.
RE: Gears has different shape of teeth.
Russell Giuliano