First 7-Speed Gearbox has a Shift Plate of DuPont Zytel

A shift plate made of DuPont Zytel nylon carries the fully integrated gear change control system of DaimlerChrysler’s 7G-Tronic seven-speed, automatic gearbox.

According to DuPont’s press release, the complex part, about 40 cm long and molded to close tolerances, maintains its vital functional properties while immersed in gear oil up to 140?C. A flexible printed circuit, based on the DuPont Pyralux system, connects the electronics with the magnetic valves and with various sensors and floats, which are also mounted onto the shift plate. The entire module was developed and is supplied by Siemens VDO Automotive AG, Regensburg, Germany. Geiger Technik of Garmish-Partenkirchen, Germany, supplies the shift plate.

DuPont’s Zytel LM70G35 heat-stabilized nylon 66 is reinforced with 35% glass fiber. According to DuPont’s press release, components of the electronic control unit work reliably regardless of the operating temperatures. The resin’s combination of high stiffness and elasticity allow snap-fits to be integrally molded into the part.

Gerhard Lepsien, key account manager at Geiger Technik, says, ?We and DuPont were both involved in the module’s development from the beginning. This means that, at an early design stage, we could influence decisions affecting processing methods and parameters and match the tool optimally with the part. DuPont helped us with mold-filling simulations and warpage analyses when evaluating various gating systems. As a result, we can respect very close tolerances without any difficulty, even though the part is a very large one.?

DaimlerChrysler’s 7G-Tronic seven-speed, automatic gearbox has been standard on its eight-cylinder models since late 2003 and is now an option on certain models in the upper-medium range.

Visit DuPont at Gear Expo booth #448.

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