Helical planetary gearbox - GIF

[Altair]

Helical planetary gearbox.




Previously:

Planetary gear set - GIF
Planetary gear set with square sun gear - GIF
Exposed planetary gears in heavy equipment - GIF
Building columns made to look like interlocking gears - photo
Cycloidal drive - GIF

[Frank S]

Depending on the angle of the helical gears able to transmit 2 to 3 times the torque as a simple straight cut planetary gear set, 4 times that of a twin countershaft spur gear set and up to 8 times the amount of torque as a simple spur gear arrangement

[malburrworks]

Depending on the angle of the helical gears able to transmit 2 to 3 times the torque as a simple straight cut planetary gear set, 4 times that of a twin countershaft spur gear set and up to 8 times the amount of torque as a simple spur gear arrangement

Wow that's a cool piece of information. I had no idea the style of gear changed the torque

[Frank S]

Wow that's a cool piece of information. I had no idea the style of gear changed the torque

It doesn't change the torque it allows the delivery of more available torque, due to the design there is more tooth contact throughout the rotation of the gears.
Think of it this way with straight cut gears as 2 mating teeth are leaving contact 2 are in the optimal contact range this is called the pitch diameter depending on the pressure angle of the tooth profile usually either 14 1/2° or 20° the next pair of gears are coming into contact there will always be some noise generated when the gears come into contact, this is unavoidable since some clearance between the rotating gears must be maintained.
Now then one way to increase the amount of torque which can be transferred from one shaft to another as in a transmission in all gear ratios other than direct 1to1 coupling is to add a second counter shaft. this effectively doubles the possible torque output also lowers stress in the transmission housing. Mack trucks for a while experimented with 3 countershafts.
Now helical cut gears spread the optimal contact duration due to the angle they are cut, this also reduces noise in the process. since the teeth slide across each other's surface rather than slamming together allowing higher torque transfer.
Planetary gears carry this process a little further #1 a straight cut planetary gear set is more compact than simple countershaft design a multitude of planets can be contained between the sun and the ring gear. stress on the housing is greatly reduced even further allowing for more compact package in the process also making it possible to have more than 1 ratio selection by either locking the ring gear or the planet carriage, and when the planetary gear setup is even further enhanced by making them helical cut this quietens them even more while adding in the advantages previously mentioned.