gear pressure angle
gear pressure angle
(OP)
We are suspect of the pressure angle we get from our gear suppliers. Documentation has been lost, etc. What is the best way to measure the pressure angle? We have an optical comparator but not a CMM. I have tried to measure the pressure angle on our comaparator but get values like 16 deg. when it should be 20 or 14.5 deg.
Thanks
Thanks





RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle
1.277 OD
1.235 PD
1.287 OVER .036" PINS
1.185 ROOT DIA.
RE: gear pressure angle
RE: gear pressure angle
Let me know what you measure and I’ll let you know what to do next.
Is the posted data what you measured or is it the spec? Do you know the center distance and mating gear data?
RE: gear pressure angle
rack made and check the gear with
the rack. The data that you provided
indicates that the gear is cut on
a .015 smaller blank. Is the pinion
a long addendum pinion?
The pressure angle at the smaller pitch
diameter is not 20 degrees. The 20 degree
pressure angle is only at the nominal
pitch diameter of 1.250 diameter.
The pressure angle at the 1.235 diameter
is 17.9908 degrees if standard cutters
were used to cut the gear.
RE: gear pressure angle
with an optical comparator unless you
know the base diameter of the gear.
You can draw the involute for the
20 degree and the 14.5 degree pressure
angle and check it at the 1.250 diameter
and the respective base diameters.
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RE: gear pressure angle
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RE: gear pressure angle
Russell Giuliano
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RE: gear pressure angle
We cut our gears to AGMA6 and deviate from the formula for backlash. Will the pressure angle be different if the OD and PD are under formula? We do have a set of Globe rack gages.
RE: gear pressure angle
The pressure angle has nothing to do with the OD and PD.
RE: gear pressure angle
But, touching on some of dimjim's points, if you apply a correction to the gear, (either a plus or minus correction) even though the generated PA remains the same, the operating PA can change. This is why gears with a large plus correction can look as if they have larger generated PAs than gears without the correction. The operating PA could be measured but you would have to include information about the center distance and mating gear; generally though, it is calculated.
Now it gets really confusing.....even though the operating PA may change, the base pitch will remain exactly the same no matter how much correction is applied to the gear proving that the generated PA is a constant which relates directly back to the tool used.
Why do you have the concerns you’ve mentioned? Are you having problems with the parts being supplied?
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RE: gear pressure angle
Remember that you are not measuring the PA, as you say in your last post. What you're measuring is the Base Pitch.
RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle
RE: gear pressure angle