Advantage of helical gears


by ank_gl
Tags: advantage, gears, helical
ank_gl
ank_gl is offline
#1
May13-09, 09:04 AM
P: 733
During internal viva, we were asked what is the particular advantage of using helical gears over spur gears. The guy next to me answered that it has higher load capacity given similar dimensions, similar material etc. Professor accepted his answer. I was kinda like

When I was asked, I said they have similar load capacities, but because of gradual loading, the wear is less, operation is quieter & a bit lesser dynamic load. So he reasoned because a helical gear has more number of teeth in contact, it has higher load capacity.

But when a spur gear transmits power, one full tooth transfers power, while in case of helical gears, part of 3-4 teeth will be engaged & will transmit power, & still would add up to only one complete tooth. So the professor was like "you are wrong!!".

I am confused!!
Phys.Org News Partner Science news on Phys.org
NASA's space station Robonaut finally getting legs
Free the seed: OSSI nurtures growing plants without patent barriers
Going nuts? Turkey looks to pistachios to heat new eco-city
minger
minger is offline
#2
May13-09, 10:35 AM
Sci Advisor
P: 1,498
You are correct. They have more teeth in contact, but the entire face of the tooth is not in contact. They roll through the face. Now they do act quieter and do have advantages.

Example. We use a program which automatically calculates AGMA allowable power and so on and so forth. We have a standard spur gear set with a 25 pressure angle. If I keep EVERYTHING the same and change from spur to a 10 helical gear, the allowable limiting horsepower for the gear set drops about 17%. At 15 helical angle, the drop is almost 25%.

Tell your prof to check out the AGMA ratings standards.


Register to reply

Related Discussions
helical path Precalculus Mathematics Homework 1
helical spring General Physics 2
Helical Spring Question! Introductory Physics Homework 21