Helical Inline Gear Motors Helical gears are not specifically much like worm or bevel gearbox systems. They are actually an alternative solution to spur gears where the tooth are parallel to the axis of the gear itself. For example, 
within an inline application, you could have either spur OR helical gears. An inline helical gearbox electric motor will usually be quieter and may bring higher loads than motors utilizing a spur gearbox. They could be more expensive in initial cost, and manufacturers have to account for axial thrust. Nevertheless, the actual fact that the helix angle may differ from 15 to 30 degrees allows for flexibility when it comes to design. They are used in in-line applications as well as parallel shaft applications.
The benefit of helical gears is that it produces a rolling action, is quieter, and has less vibration compared to spur gears. In addition, it produces less friction and permits more the teeth to be engaged concurrently as one’s teeth roll across each other.
There are myriad types of gearing. Some manufactures make use of spur gears rather than helical gearing, for example. However, there isn’t as much surface contact, as noted above and as a result there is more noise and much less torque transfer possible.
Another program where noise is common are planetary equipment systems, where in fact the one gear is completely within the other. They also require grease lubrication plus they must be built with expensive materials in order to maintain a long-existence and bearing integrity. An easier variant, internal gearing, suffers from the same issues and can only be utilized with parallel shaft.
Finally, hypoid gearing may be best understood because similar to bevel gearing, but with the apparatus axes not intersecting. The sliding actions can create huge amounts of warmth and the alignment helical spiral bevel gear motor requires great care.