Helical Inline Gear Motors Helical gears are not specifically comparable to worm or bevel gearbox systems. They are in fact an alternative solution to spur gears where in fact the tooth are parallel to the axis of the gear itself. For example, within an inline application, you can have either spur OR helical gears. An inline helical gearbox motor will usually be quieter and will carry higher loads than motors using a spur gearbox. They could be more expensive in initial cost, and manufacturers need to take into account axial thrust. However, the fact that the helix position may differ from 15 to 30 degrees allows for flexibility with regards to helical spiral bevel gear motor design. They are found in in-line applications and also parallel shaft applications.

The advantage 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 tooth to be engaged concurrently as the teeth roll across each other.
There are myriad types of gearing. Some manufactures make use of spur gears rather than helical gearing, for instance. However, there is not 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. In addition they require grease lubrication and they must be constructed with expensive materials in order to maintain a long-life and bearing integrity. An easier variant, internal gearing, suffers from the same problems and can only be used with parallel shaft.

Finally, hypoid gearing could be best understood since similar to bevel gearing, but with the apparatus axes not intersecting. The sliding actions can create large amounts of high temperature and the alignment needs great care.