Posted by Colin on February 06, 2010 at 06:17:38:
In Reply to: Re: Question about gear pitch posted by Jim Pollock on February 05, 2010 at 19:49:34:
See below 30T/30T gears 6DP at 5.257 Centres.
They have to be heavily profile shifted ( factor 0.9)and have a poor contact ratio so they will need to be very accurate to get the best running.
Not ideal- you would be better to use helicals.
I can send you a drawing of the gear profiles.
Do you have AutoCad?
Contact Ratio= 1.20
DP 6.00
Pressure angle 20.0000
Operating Pressure Angle 26.6597
Hob tip rad. 0.0786
Centre dist. 5.2570
Pinion
======
No.of teeth 30
AMC 0.9010
Addendum 0.3168
O/Dia. 5.5478
(O/D reduction) 0.0859
Root/dia. 4.8837
Hob Offset 0.1502
Total tooth depth 0.3321
Wheel
=====
No.of teeth 30
AMC 0.9010
Addendum 0.3168
0/Dia. 5.5478
(O/D reduction) 0.0859
Root dia. 4.8837
Hob Offset 0.1502
Total tooth depth 0.3321
Measuring data
==============
Min.total backlash .2
Max.total backlash .25
Fraction of b.lash on pinion .5
Pinion Hob/Cutter Offset for mean backlash = 0.1120
Wheel Hob/Cutter Offset for mean backlash = 0.1120
Pinion data:-
------------
Base tan.length over 5 Teeth 2.2868 / 2.2618
Dist.across 0.2880 Dia.pins 5.4266 / 5.3743
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Wheel data:-
------------
Base tan.length over 5 TEETH 2.2868 / 2.2618
Dist.across 0.2880 Dia.pins 5.4266 / 5.3743