An exciting excursion into the universe of gear manufacturing

By Bhalchandra Chorghade, Editor, CNCTimes.com

"Solid, complex and really ingenious" - this is how our colleague sums up the impressions that come to his mind when he is asked about a very specific clamping device. This statement makes us curious and we ask which workpieces are to be fixed with this clamping device. The colleague explains: "The planetary gear carrier is an essential component of an automatic transmission. It carries the planetary gears, which are needed to couple the sun and ring gears."

Granted: Explaining a gearbox is complicated at first glance. Let us start from the beginning and clarify a legitimate question right away so that not only technicians and engineers are able to understand this technology: Where does the name "planetary gear carrier" come from?

We learn: "The name of the components is based on the solar system: The central point of an automatic gearbox is the sun wheel [3], which is orbited by several shafts. These shafts have gear wheels, the so-called planetary gears [2] and the movement is similar to that of planets around a central sun. This structure is surrounded by a ring gear [1]. As the name suggests, the planetary gear carrier carries the planetary wheels [4].“

Back to the gearbox: By changing gears, the interaction of the various gears mentioned above changes and the drive operates in the optimal speed and load range.

This simple explanation is enough to get us started. However, we will use the precise technical explanations in the rest of the article, our colleague, an expert in clamping technology, will chime in with his explanations.

You can look forward to an ingenious clamping concept, an impressive design, many advantageous functions and explanations from experts in this area - let's go!

This clamping device still amazes us and our colleagues even though the implementation was made a couple of years ago. The resonating pride is unmistakable when he talks about this project: "This concept certainly stands out among the ones we implement in clamping technology. In terms of the design, the clamping concept and also the project sequence." We will learn more about this later.

To begin with, we are particularly interested in the technical challenges that had to be met in this project. Our colleague Gerhard explains: "The requirements for the clamping concept mentioned by the customer were considerable at the beginning of the project. The focus is on a bulky component that is to be clamped with low distortion and fixed with low vibration by means of enormously high torques. Quite demanding for a milling operation with high machining forces!"

To meet the requirements, our employees have combined the best of two worlds in the clamping concept: "The primary clamping is carried out by a clamping device "typical" for EMUGE-FRANKEN. A diaphragm chuck with visually striking clamping jaws is used. We use a "classic" concept of collet chuck and hydraulically actuated clamping piston for the additional internal clamping."

We are puzzled - another diaphragm chuck? We ask why our colleague opted for this concept. The reason given is: "Considering the fact that the clamping surface on the workpiece is relatively short and the large working space required for the tools, one immediately thinks of the clamping jaws of a diaphragm". At this point, we are happy to refer to the other success stories in which diaphragm chucks are used.

But let's get right back to this clamping device. The impressive size and the unusual design make it necessary for us to let our colleague show us the individual components of the clamping device. "The proverbial solid foundation is a specially designed plate, on which the other components are installed. All hydraulic and pneumatic lines, including the external connections, are worked into this plate." We also notice the distinctive hydraulic connections and the mounts for the load bars. The latter are absolutely necessary given the total weight of over 160 kg!

As already mentioned, the external clamping concept forms a diaphragm. The five clamping jaws are screwed to the diaphragm and rest against the workpiece due to its inherent tension.

The orange slots of the collet are clearly visible through the clamping jaws in the view from above. The alignment unit is located in an exposed position above the two clamping. 

We do not want to focus only on the impressive construction, but also take a look behind the scenes. We ask ourselves why two clamping systems are combined and what the alignment sleeve is needed for.

https://www.emuge-franken-group.com/de/en/planetary-gear-holder/a/planetary_gear_holder

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