1 year ago

MDA Technologies 2/2015

MDA Technologies 2/2015

Safety clutches –

Safety clutches – drive technology for low temperatures to -48 °C Simone Winkler With daytime temperatures of well below 0 °C, machines and components at raw material production facilities in Siberia and Mongolia face enormous challenges. Mayr has now developed its element clutches in such a way that they are now also suitable for use at very low temperatures. Tests have proven their functionality at low temperatures of -48 °C. Simone Winkler (M.A.): public relations, Mayr Antriebstechnik in Mauerstetten Your breath freezes and crackles, the snow underfoot crunches when walking as if crossing over broken glass, and truck motors run continuous from October to April, day and night, otherwise they would freeze. In Siberia, the extreme cold controls a lot of everyday life, as temperatures plummet to -50 °C during the nine winter months. Not only are the coldest inhabited areas on earth located in Siberia and Mongolia, it is also one of world’s richest areas in raw materials. Machines that are used to mine and process raw materials, such as coal and ore, are exposed to extreme conditions. Cold-resistant constructions are required. “For high-strength and fully hardened components, low-temperature embrittlement increases the risk of components breaking and there is hardly any technical information available on reliable theoretic designs of components,” explains Helmut Kleinheinz, Sales Manager at Mayr 01 The EAS element clutch was successfully tested on an inertia dynamometer at low temperatures and harsh operating conditions 02 The adjusted construction of the specially-designed EAS element clutch guarantees overload protection even at very low temperatures of down to -48 °C 20 MDA Technologies 2/2015

MACHINE ELEMENTP Antriebstechnik. “This means that use in areas with low temperatures must always be critically assessed. Reliable statements regarding suitability can only be made if the constructions are also tested under the expected conditions of the specific applications.” Adjusted for the extreme EAS quality and overload clutches from Mayr are made of high-quality material as standard and have hardened functional surfaces, which is the only way the required release accuracy and durability can be achieved. Like all of the other standard clutches available on the market, they are not designed for use at extremely low temperatures. To still be able to provide its customers with reliable, technically safe products for extreme conditions, the company has now developed a low temperature design and completed comprehensive practical testing. “We have extensive specialist knowledge when it comes to development and construction and have access to the latest and unique testing facilities,” explains Helmut Kleinheinz describing the prerequisites of the clutch specialist. These tests enabled the EAS element clutches to be modified in such a way that they could withstand extremely low temperatures with the same level of robustness. Unlatching in climate chamber Mayr Antriebstechnik has a wide range of testing facilities ensuring all of its products undergo extensive functional testing. “For use at low temperatures, the modified EAS element clutch (size 0) was tested at -48 °C on an inertia dynamometer with a connected climate chamber,” explains Günter Hable, a design engineer at the family run business in Mauerstetten, Germany. The clutch was set at a torque of 2400 Nm and was able to withstand 100 high-speed overloads without any damage. To ensure that the climate chamber was closed at all times, the clutch was re-engaged automatically using an integrated pneumatic engaging device. This engaging device was used to consciously simulate operating errors to additionally initiate as many impact loads on the components as possible. Application errors are, for example, generated by re- engaging at a differential speed, i.e. during the phaseout period when the clutch has already been triggered. During use at low temperatures, it must particularly be ensured that the application as a whole is taken into consideration to guarantee the correct connection of the overload clutch to the drive train. At very low temperatures, thread-specific characteristics in particular can cause a massive additional burden. This is why risk and application testing is always completed with the customer at the plant in Mauerstetten. Overload protection for low temperatures The tests in the climate chamber prove that the special design of the EAS element clutch is suitable for use at very low temperatures down to -48 °C. These safety clutches generally use individual elements to provide overload protection for drives with very high torques within a compact space. They are suitable for limiting the torque on heavy and high-speed drives and ensure that large centrifugal masses can phase out freely in the event of an overload. During normal operation, positive locking EAS element clutches accurately transfer the set torque without any backlash and ensure exact shutdown accuracy in the event of an overload. Photograph: Shutterstock/Vladimir Melnikov About Company name: Mayr GmbH Headquarters: Mauerstetten, Germany Employees: ca. 1,000 worldwide Products: Torque limiting clutches, safety brakes, shaft couplings MDA Technologies 2/2015 21


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