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A perfect fit When

A perfect fit When considering capital expenditures, investments often centre on the idea of optimising the value proposition while keeping the costs as low as possible. Simply put, companies want to only pay for what they need and nothing more. When custom solutions are not practical, how can standard products fulfill requirements without being oversized and overvalued? The answer is a well-tailored solution that fits to the customer’s application. MOTION AND DRIVES How can a standardized industrial gear unit fit exactly to the demands your application requires? How can digital and mechanical technologies combine to thrive such a solution? And how does an engineer select a gear unit with the optimal fit? SEW-Eurodrive developed its latest iteration of it’s X-series industrial gear units with exactly these questions in mind. Authors: Mark Zeller, M. Eng., is Product Manager for Industrial Gear Units at SEW-Eurodrive in Bruchsal Christian Rüttling, M. Sc., is Market Manager Industrial Gear Units at 01 SEW-Eurodrive Rendering of in Bruchsal the Generation X.e drive unit 20 WORLD OF INDUSTRIES 3/2019 A tailor-made solution SEW-Eurodrive has worked to develop a tailor-made industrial gear solution by posing the following question: How can a drive be offered that is not oversized in any way? Furthermore, how can a drive bring only the value proposition the customer needs and does not charge for solutions the customer does not require? The result from this investigation concluded in an overhaul and optimization of the existing X-series standard product line for bevel and bevel-helical gear unit series used in heavy industrial solutions. With thousands of X-series units installed around the world and testimonials of hundreds of customers over the last decade, understanding the product demands are clear. And with global industries, including coal and other mining operations marching towards digitalisation and Industry 4.0 (now a fundamental part in high investment industry such as coal material handling), the requirement for the further development of accompanying software technologies must be equally as important. Therefore, in addition to a hardware optimization, the tools and calculation landscape were rebuilt from scratch so that latest standards and cross-border dependencies can be considered. With this, the Generation X.e was created. The improvements from hardware side conclude as the following: 1. Improved bevel pinion housing in the input stage 2. Optimized preload settings for shaft bearings 3. Thermally improved oil levels 4. Contactless sealing systems for input and output shafts 5. New fan and fan guard concepts 6. New tooth topology in the gearing People working in the Coal Industry with knowledge on drives know that the options do not look like a reinvention of the gear unit. However, the single improvement alone is not the innovation. Though each option itself can enhance the fit to specific customer needs, it is the collection of improvements, along with the recalculation of performance from modern standards, as well as with current technologies that allows manufacturers to offer just the right value. True to the principle of the Greek philosopher Aristotle, “the whole is more than the sum of its parts.” Selection When evaluating the gearing demands of the coal industry, visualizing the design requirements could help with the better understanding of the design parameters for a well-tailored solution. Plotting these characteristics on a spider diagram, giving each axis the numbers representing the importance of the parameter, a scale of 1 (low) to 3 (high) can be used. The parameters might include operational area, working load, peak loads, temperature conditions, and acoustic performance. A standard gear unit from most any manufacturer will be a balance between all design parameters. For an underground conveyor, the following parameters might be considered: n Operational Area: Dusty limited access around the unit, and limited serviceability (3) n Working Load: Continuous demand for more than 10 hours per day in a steady and safe operation conditions (2) n Peak Loads: Infrequent starts/stops with rare jams (1) n Temperature conditions: Mild ambient temperatures with high input powers and maximum permissible surface temperatures based on the environmental conditions (3)

n Acoustics: Often loud environment requiring ear protection. (1) In the example of a conveyor system in the coal industry, the most important design parameters include operational area / serviceability, working load and thermal capacity. Efforts should be made in optimizing these areas while accepting the standard performance in other areas. With respect to the operational area and serviceability, in an underground and dusty environment, the lifetime of the seals and bearings needs to extend a certain period since service cannot easily be performed without risking contamination. With respect to the working load, designs should permit higher motor powers, with longer mean time between failures (MTBF) for the gears and bearings. For increased thermal capacity, a number of options could be employed, but the availability of certain options are likely restricted, such as access to cool water supply for oil-water coolers. Therefore, plotting the parameters to the spider diagram shifts yields the chart below: In this example, the gear unit needs to reach the prescribed requirement in three of five sections. A standard gear unit may not achieve the target performance within the target areas, and increasing the frame size may or may not improve the performance in some or all areas. A custom gear unit may achieve high performance in all areas, yet not all areas may need to be optimized. In this case, the customer may need to pay a higher price for solutions he did not ask for. The ideal solution would be if the gear unit improves only in the categories that are required, with the rest remaining the standard, thereby keeping the overall price low. Therefore, the customer needs a gear unit that is improved thermally and with long life components capable of moderate loads, but which keeps the standard technology in the other categories. That’s new: What is shown with the yield of the chart is an illustration on what is happening within the selection after the customer sent in his requirements. The cross-linked calculation tool adapts the requirements and translates them into the needs of a thermally demanded and long lifetime needed gear unit. With these presettings, the tool calculates the ideal combination of features while keeping the dependencies of the features as restrictions. Afterwards, the plant processes will be initiated with the information coming from the selection tool so the value chain of data thrives from the first contact to the assembly of the features. This gives “perfect fit” a new meaning. Benefits 02 Optimized set up for a conveyor drive An optimized standard gear unit with improved thermal behavior and bearing lifetime can bring benefits to further enhance the selection for the customer. In addition to improving the performance and life of the gear unit, the design enhancements can result in lower total cost of ownership (TCO) over the lifetime of the gear unit. Higher efficiency through a lower oil bath temperature result in electrical energy savings as well as to longer oil changing intervals. The reduced oil level helps in saving resources and a repeating invest with every oil changing interval. With contactless sealing systems a service is not needed at all for this feature. If a specific bearing lifetime is requested, a smaller unit size is possible since the optimization can be calculated and improved within this area. Furthermore, optimized designs will bring higher safety to units installed within potentially explosive environments such as ATEX zones which require a gear unit’s surface temperature be below certain limits. Especially in the underground area but also in dusty above ground applications, an explosion risk must be mitigated. The thermal capacity that the gear units need to have for these kind of environments can be improved again with the stated features without enlarging the gear unit to get a larger housing surface or charging the customer for the other enlarged features he did not ask for. Conclusion People will recognize and feel the difference between a standard suit from a store and a well-tailored suit fitted to the individual. The Generation X.e gear units will ensure that this feeling of the perfect fit can be achieved through targeted improvements and design optimizations on standard products without charging for a totally custom solution. Everyone needs one Servocouplings for all drive constellations –inexpensive price –wide product range –short lead time your reliable partner MAYR_EN.indd 1 12.03.2019 13:31:02 WORLD OF OF INDUSTRIES 3/2019 21


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