Couplings exhibit efficiency in tractor transmission

As part of the CLAAS Group, the 100% subsidiary CLAAS Industrietechnik focuses on drive technology including gearboxes and hydraulics. CLAAS Industrietechnik products are used both within the CLAAS Group and, increasingly, in a variety of sectors involving many other customers. The company is based in Paderborn, Germany and employs about 600 employees to produce solutions which are robust, lightweight and durable.

For the ARION 500/600 series tractor, the CLAAS engineers developed the EQ200, with continuously variable transmission. This particular transmission exhibits a high level of efficiency – more or less constantly at any speed – thanks to a combination of two variable axial-piston pumps, stepped planetary gearset and a double-clutch unit. Gear changes are possible – even under load – without abruptly increasing speed and torque, which leads to consistently steady acceleration from 0-50km/h. Furthermore, the tractor can be driven at a top speed of 50kph with fuel-saving engine speeds of 1500rpm.

"The EQ200 is a power-split transmission and the function of the coupling is to transmit rotation from the electric positioning motor to the hydrostatic module," explained Thomas Kottmann, Member of the Purchasing Department, Paderborn. "The coupling has to provide elastic transfer of the forces and, because it’s operating in a hydraulic system, we need very clean parts."

Huco Dynatork engineers were able to recommend its multi-beam couplings to perform as required within the gearbox. The coupling’s helical-cut design provides a higher torque capability and reduced backlash when compared to single beam couplings and will readily accommodate axial motion and angular and parallel misalignment. Most couplings stocked by traders, merchants and catalogue parts specialists are supplied in the as-machined condition, meaning that they aren’t treated post-production to remove all possible contaminants. While this is fine for the vast majority of coupling applications, for hydraulic transmission applications this can have serious consequences for the reliability of the system.

"Such couplings can present problems to a hydraulic gearbox. For example swarf and chips will likely be present from the machining of the beams," said Kottmann. "However, by approaching Huco directly, we received an excellent solution to this issue. Huco was able to offer its stainless steel multi-beam coupling complete with a full deburring and cleaning service. As a result, we do not have any issues with swarf or metal chips contaminating the hydraulic system."

Commenting on the flexibility of Huco Dynatork, brand Managing Director, David Lockett, added: “We’re always happy to work with our customers to deliver a special service or solutions that will improve their experience of our product. We’ve invested heavily in our Lean manufacturing capabilities, and this allows us to tailor our delivery for orders of any size. By offering the cleaning service to CLAAS Industrietechnik, we were able to help them ensure the reliability of their product and protect their reputation.” The first prototypes of the CLAAS EQ200 transmission were assembled in 2008.