Gear design based on max holding force? 1

[Darken99]

I am designing a pinion and gear to be used in a design project that I am working on. I am having an issue with the maximum torque being applied on the pinion and gear. I I was just wondering if someone knows how I would go about solving for a maximum holding force rather then operational rotational force. I know how to design the pinion and gear based on when it is moving but I don't need it to be moving for my max design load.

Anyone have any ideas?

Thanks

 

[diamondjim]

I think it is typical to use twice the
operating load as the maximum load and
1.4 for the max operating loads.
It does depend on your application however.

 

[Darken99]

Ok I never really explained my problem very well. I have a arm with a partial gear on the end of it. The arm is pined in the middle with a 300 lb max design load applied at the other end. I want to design the pinion and gear based on that 300lb max design load (design factors already included). All the equations I have seen are based on the actual load and they take into account for the design factors in the equations. I was thinking the equation I was looking for had to take into account the contact area and the max design force being applied to it.

Thanks

 

[diamondjim]

The basic tooth load equation is
W = S b Y
where
W = Max load Pounds
S = Max allowable stress (Usually 40% UTS)
or UTS divided by the Safety Factor
for that conditional load.
b = gear face width
Y = Lewis Y factor (based on the number of teeth
of a complete 360 degree gear)

The pinion will normally be the weakest member
unless you go to a modified tooth form and then
also use a stronger material for it.
I have an excell spread sheet with the Y factor
if you need it for normal, 25 percent long, and
50 percent long addendum gears and pinions and
20 degree pressure angles.

 

[Darken99]

Thanks a bunch... that is what I was looking for.