The "rounded" design allows constant contact to be maintained between two gears. If they were of the simpler design with flat faces on the teeth, they would simply wear to this shape anyway, but in the process they would also end up with slack between them. A helical twist is also usually employed which improves the transition between adjacent teeth, and consequently reduces noise. Ever hear a transmission with a loud whine in reverse gear? IIRC, it's because they didn't use the helical twist trick on the reverse gear. I have no idea why they wouldn't though. If we're lucky, an ME will be along in a bit and explain all of this for us much better.
Yep. Straight cut gears are cheaper to make. Since people don't do as much reversing as going forward, it's probably a good compromise on cost vs comfort.
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The "rounded" design allows constant contact to be maintained between two gears. If they were of the simpler design with flat faces on the teeth, they would simply wear to this shape anyway, but in the process they would also end up with slack between them. A helical twist is also usually employed which improves the transition between adjacent teeth, and consequently reduces noise. Ever hear a transmission with a loud whine in reverse gear? IIRC, it's because they didn't use the helical twist trick on the reverse gear. I have no idea why they wouldn't though. If we're lucky, an ME will be along in a bit and explain all of this for us much better.
Yep. Straight cut gears are cheaper to make. Since people don't do as much reversing as going forward, it's probably a good compromise on cost vs comfort.
Makes sense to me.