Waunakee, WI , 2018-10-25
Worm, Spiral Helical Bevel and Helical Inline Gear Motors Gearbox motors are critical in conveyor systems because they help convert torque as necessary along the travel path. There are several varieties, and they chiefly differ in terms of how they change orientation and the amount of torque overload that they can handle. The below motors differ not just in mechanism of interaction between the shafts, but also in the type of the teeth used in the gears themselves. In nearly every conveyor system application, finding the right combination of these very different gearbox motor option is based on the speed and load considerations, temperature requirements as well as system envelopes and overall budget.
Worm Gear Motors
A worm is actually a toothed shaft that drives a toothed wheel. The whole system is called a worm gearbox and it is used to reduce speed and/or transmit higher torque while changing direction 90 degrees. Worm gearing is a sliding action where the work pinion pushes or pulls the worm gear into action. That sliding friction creates heat and lowers the efficiency rating. Worm gears can be used in high-torque situations compared to other options. They are a common option in conveyor systems because the gear, or toothed wheel, cannot move the worm. This allows the gearbox motor to continue operation in the case of torque overload as well as emergency stopping in the case of a failure in the system. It also enables worm gearing to handle torque overloads.
That same feature, however, can also lead to higher operating temperatures compared to bevel gearbox motors when coming from the same manufacturer. The increased heat results in lower efficiency and the parts eventually wearing out.
Spiral Helical Bevel Gear Motors
Bevel gears are also used to transmit power between shafts, but are slightly different than worm gears. In this case, there are two intersecting shafts that can be arranged in different angles, although usually at a 90 degree angle like worm gearbox systems. They can offer superior efficiency above 90 percent and produces a nice rolling action and they offer the ability to reverse direction. It also produces less friction or heat than the spur gear. Due to the two shafts, however, they are not beneficial in high-torque applications compared to worm gearbox motors. They are also slightly larger and may not be the right fit when space considerations are a factor and heat is not an issue.
Helical Inline Gear Motors Helical gears are not specifically comparable to worm or bevel gearbox systems. They are actually an alternative to spur gears where the teeth are parallel to the axis of the gear itself. For example, in an inline application, you can have either spur OR helical gears. An inline helical gearbox motor will usually be quieter and can carry higher loads than motors using a spur gearbox. They can be more expensive in initial price, and manufacturers need to account for axial thrust. However, the fact that the helix angle can vary from 15 to 30 degrees allows for flexibility in terms of design. They are used in in-line applications as well as 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. It also produces less friction and allows for more teeth to be engaged simultaneously as the teeth roll across each other.
Why Nord Doesn’t Use Other Gearing
There are myriad types of gearing. Some manufactures use spur gears instead of helical gearing, for example. However, there is not as much surface contact, as noted above and as a result there is more noise and less torque transfer possible.
Another system where noise is common are planetary gear systems, where the one gear is completely within the other. They also require grease lubrication and they must be built with expensive materials in order to maintain a long-life and bearing integrity. A simpler variant, internal gearing, suffers from the same issues and can only be used with parallel shaft.
Finally, hypoid gearing may be best understood as similar to bevel gearing, but with the gear axes not intersecting. The sliding action can create large amounts of heat and the alignment requires great care.
Learn More About NORD Gearbox Motors To learn more about integrating our drive units and controls for your needs, contact us today . Our team of consultants will review your project specifications and work with you to devise the right strategy for long-lasting system success with low maintenance and maximum efficiency. With a variety of gearboxes and industry-leading protection for our motors, we stand behind our solutions for your conveyor and other needs. We have a history of success in the agricultural, steel, airport and many other industries and look forward to finding the best solution for your needs.