Q&A with Friedrich Wölfel

Head of Sales Division at KAPP NILES

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What is e-mobility, and how is KAPP NILES working to establish itself as a pioneer in this growing field?

E-mobility refers to the use of vehicles that are powered by electricity. This includes not only electric cars, but also e-bikes, e-buses, and e-trucks. Due to the number of vehicles and the gears installed in them, the biggest influence on our business is, of course, passenger cars. And it is precisely in this segment that we began 10 years ago with customers to produce the first prototype gears for them and to build up experience for these new and demanding applications. In the meantime, e-bike and e-truck applications are requested more and more often. E-bike gears are characterized by their extremely small size. Of course, it’s the other way around when it comes to e-truck applications today with gear diameters up to 500 mm.

How does e-mobility factor into gear manufacturing?

E-mobility certainly has a significant influence on gear production. First of all, of course, it is noticeable that the majority of transmissions for pure electric vehicles only require four gears. And that is far less than the number of gears in conventional automatic or dual-clutch transmissions. However, the quality requirements for the gears for this new technology are typically far higher than for combustion engines — and this compensates to a certain extent for the lower capacity required for production. In addition, especially in the last two years, massive investments have been made in the production of these new transmissions. The use of existing machines from conventional gearbox projects at our customers has hardly been discussed so far due to the parallel production and the high-quality requirements in the electrical sector.

Why must the drivetrain in electric vehicles be more optimized in comparison to conventional combustion engine vehicles?

First and foremost, the gaze — or rather the ear — went in the direction of the noise of the transmission. Since the masking noise of the combustion engine is eliminated, especially at low speeds, transmission noises are perceived more frequently. In the meantime, a second topic has been added. In order to improve the range of electric vehicles, power dissipation must also be reduced in the transmission. This is now achieved by means of ultra-fine surfaces on the gears, which are produced directly on the gear grinding machine by fine or polish grinding technology. KAPP NILES offers both technology options and, in addition, a proprietary technology for a separate polishing process following gear grinding and strength blasting.

Grinding of an e-mobility shaft with a combined grinding worm. (Courtesy: KAPP NILES)

How is KAPP NILES tackling this challenge?

We put a lot of development effort into these two topics. To offer an alternative to the comparatively complex 100 percent component testing by means of single-flank rolling testing, noise-conspicuous gears can now be detected via KAPP NILES Process Monitoring during gear grinding itself. For fine grinding and polishing, we have built up a very broad know-how in technology and tools. In particular, new dressing tools with highest quality standard manufactured in-house by KAPP NILES make a significant contribution to the highest gear and surface quality. 

What is waviness analysis, and why has this become important for assessing the quality of gearing in electric drives?

In the waviness analysis, the measurement records of the conventional tactile gear measurement are also analyzed with regard to the waviness on the tooth flanks. For this purpose, the measurements (profile and helix) of an all-tooth measurement are lined up phase-correctly. The systematic uniform deviations are then determined in this combined measurement chart and displayed in an order spectrum, which corresponds to an effective waviness.

In this way, the waviness can be efficiently quantified and reliably evaluated using limit values. This enables the early detection of noisy components.

What has been the market response to what KAPP NILES is accomplishing in the e-mobility field?

Our now very high market share in this segment is proof that KAPP NILES can supply the best gear grinding and measuring machines and technology for such components, both in terms of achievable quality and cost-effectiveness. Especially with the first electric transmission produced worldwide with exclusively finely ground/polished gears, we were one step ahead of our competitors here. 

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