Helix Angle

o0norton0o said:
Yes, in some cases. If a gear set is going the same speed they can be slipped in or out of gear... People do it all the time shifting gears in a standard transmission without using the clutch by just matching the engine speed to the rolling speed of the gear train....... Is it recommended? A) no Can it damage gears? A) Yes

My clutch cable broke on my motorcycle when I was in town right near the highway. I started the bike and pushed it to get it going then gingerly slipped it into first gear with a clunk. Once I sped up, I put my foot on the shift lever with slight pressure and when I checked the throttle it slipped nicely into second gear. I did this all the way home without any nasty sounding clunks or grinding....

Half nuts are a good example of helical gear interfaces that are engaged and disengaged on the fly...
Click to expand...
If you have ever watched these guys, They literally JAM the gears very fast, I drove for years never used the clutch.

 
Helical gears, as John said, can generate very large thrust loads depending on helix angle and torque applied. The beauty of helical gears is that there are multiple teeth carrying the load at once. This tends to quiet the gear noise as there’s less shock in load transfer. In extreme load cases such as Naval reduction gear sets for steam turbines. they use double helical gears with opposing helix angles to eliminate thrust and to further share the load with additional teeth. Very expensive gears. In actuality the teeth are much finer than the cartoon below.
1708306470510.jpeg

Links to a newer version of my college machine design text and a very good short pdf from NASA below if you want to dig into the theory.



 
GT-6 Racer said:
Helical gears, as John said, can generate very large thrust loads depending on helix angle and torque applied. The beauty of helical gears is that there are multiple teeth carrying the load at once. This tends to quiet the gear noise as there’s less shock in load transfer. In extreme load cases such as Naval reduction gear sets for steam turbines. they use double helical gears with opposing helix angles to eliminate thrust and to further share the load with additional teeth. Very expensive gears. In actuality the teeth are much finer than the cartoon below.
View attachment 478952

Links to a newer version of my college machine design text and a very good short pdf from NASA below if you want to dig into the theory.



Click to expand...
The issue is there is no shifting double helix gears and for what I'm planning I need to mesh and unmesh them in the transmission
 
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