PECM Issue 20 2016 | Page 39

This configuration offers some very Tilting and torsional stiffness are high, significant advantages over other gear leading to precise positioning and high layouts. For instance, all the parts fit inside repeatability. In fact the Melior Motion the ring gear making it a compact unit. was designed with robot applications very Because there are a number of planet much in mind, hence its compact size, low gears, there are many teeth meshing with maintenance, and high performance. one another, each pair transmitting power In conclusion we can say that planetary and adding together to give a high torque gearheads are enabling more and more capability in a compact unit. potential users to think about adopting The multiple meshing of teeth also helps precision servo drive technologies for their to significantly reduce backlash compared machines and systems. First time users to a gear system where there is only one in particular may appreciate technical meshing pair. Also, because the power support from a company like Drive Lines, transmission is spread equally across each which not only supplies gearheads and planet gear, there is an innate symmetry associated equipment but also has a which helps prevent the gearhead from flexing under load. Thus it can be seen that planetary gearheads have a lot to attract designers of precision drive mechanisms. They are wealth of expertise and experience in Now to look in more details at a particular specifying precision drives for a wide planetary offering, let’s take the Melior range of applications. Motion range, again from Premium Stephan. Established over 30 years ago, Drive Lines has worked on applications as diverse as compact, powerful, accurate and robust. This has many design details that help hot drape formers, golf buggies, lifting In order to make planetary gearheads ensure performance is as precise and systems, laboratory equipment, cement even more attractive to potential users, reliable as possible. For instance, the mills drives and a door closure for a manufacturers such as Premium Stephan gear teeth have a unique profile that medieval cathedral. make them in a range of formats, so that guarantees backlash is less than 0.6 individual requirements can be met from a arcmin and will not change by more standard model or one that has been only than 10% over the nominal operating slightly modified. lifetime of 20,000 hours. This reduces the Premium Stephan can supply their gearheads as sub-assemblies, enclosed costs associated with initial set up and subsequent servicing and replacement. If the sun gear is turned, the gearboxes or fitted to a motor to form a Further, the Melior Motion’s torque meshing teeth cause the unitary component. They are available in capacity is exceptional for such a small planet gears to turn, which a range of sizes and can be supplied with footprint, so energy efficiency is high. Thus then cause the ring gear to either solid shafts (with shaft length to heat generation is low, allowing standard turn. It sounds complicated match the application) or hollow shafts, lubricating oils to be used rather than and looks hypnotic, but in the latter allowing a feed-through of expensive specialist ones. It also leads to fact is very simple. It is also cables. Generally they are designed for low starting torque, inertia and braking notable that the ring gear use with standard mineral oils, although loads, and therefore smooth and reliable turns in the same direction specials are available. operation. as the sun gear.