ae-bt
Mechanical
- Aug 23, 2010
- 5
I am trying to calculate some gear parameters for an epicyclic gearbox, and I am struggling with a few aspects...
I am using the formula in tables 4.4 and 5.1 found in the 'Elements of Metric Gear Technology' manual by SDP/SI (found here
First problem:
When I calculate the involute function aw (table 5.1, no 5) of a ring gear with a profile shift of approx. -0.5 or less, I end up with a negative number. And looking at the involute function table the entire table is positive, so something has gone wrong there. Or does this naturally limit the amount of profile shift possible on internal gears?
Second problem:
When I calculate the working pressure angle of the Sun/Planet pair I get a different value when compared to the Planet/Ring pair. Is this correct?
If it is correct, which value do I use to work out the Working Pitch Diameter of the planet gear?
The arbitrary values I am using to get my code working are:
Pressure angle: 25 degrees
Module: 3
Sun: 15 teeth, -0.5 profile shift
Planet: 15 teeth, 0.5 profile shift
Ring: 45 teeth, -0.5 profile shift
Many thanks in advance.
I am using the formula in tables 4.4 and 5.1 found in the 'Elements of Metric Gear Technology' manual by SDP/SI (found here
First problem:
When I calculate the involute function aw (table 5.1, no 5) of a ring gear with a profile shift of approx. -0.5 or less, I end up with a negative number. And looking at the involute function table the entire table is positive, so something has gone wrong there. Or does this naturally limit the amount of profile shift possible on internal gears?
Second problem:
When I calculate the working pressure angle of the Sun/Planet pair I get a different value when compared to the Planet/Ring pair. Is this correct?
If it is correct, which value do I use to work out the Working Pitch Diameter of the planet gear?
The arbitrary values I am using to get my code working are:
Pressure angle: 25 degrees
Module: 3
Sun: 15 teeth, -0.5 profile shift
Planet: 15 teeth, 0.5 profile shift
Ring: 45 teeth, -0.5 profile shift
Many thanks in advance.