Helical Inline Gear Motors Helical gears are not specifically much like worm or bevel gearbox systems. They are in fact an alternative to spur gears where the tooth are parallel to the axis of the gear itself. For example, in an inline application, you could have either spur OR helical gears. An inline helical gearbox motor will usually be quieter and can bring higher loads than motors utilizing a spur gearbox. They can be more helical spiral bevel gear motor expensive in initial cost, and manufacturers have to take into account axial thrust. Nevertheless, the fact that the helix position may differ from 15 to 30 degrees permits flexibility in conditions of design. They are used in in-line applications and also 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. It also produces much less friction and permits more tooth to be engaged concurrently as the teeth roll across one another.
There are myriad types of gearing. Some manufactures use spur gears rather than helical gearing, for example. However, there is not as much surface contact, as mentioned above and as a result there is more noise and much less torque transfer possible.

Another system 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 constructed with expensive materials in order to maintain a long-life and bearing integrity. A simpler variant, internal gearing, is suffering from the same issues and can only be utilized with parallel shaft.

Finally, hypoid gearing could be best understood as similar to bevel gearing, but with the gear axes not really intersecting. The sliding action can create huge amounts of high temperature and the alignment requires great care.