Worldwide competence center for shift quality
[ Published in HOERBIGER@MOTION November 2014 ]
Compact, clean and upscale: every detail turns out to be functional and in exactly the right place at Mercedes-Benz's Rastatt plant location of the Gaggenau production site. Here, all manual transmissions for the new Mercedes-Benz A- and B-Class and a number of other vehicle series featuring the star emblem roll off the assembly line. A closer look reveals more – and shows what HOERBIGER has to do with it.
More than ten million transmissions to date have emerged from the Gaggenau site, which measures close to 4.5 million square feet (412,000 square meters), and its Rastatt plant location, covering another 2.5 million square feet (238,000 square meters) of floor space. With a total of 6,600 employees, together they form the manual shifting galaxy in Mercedes-Benz's automotive cosmos. At present, it is the only factory worldwide for manual and automated transmissions of the historic brand. HOERBIGER also enjoys a unique position in Gaggenau; after all, the company has acquired the status of being the only outside supplier for friction systems here.
The two to three million synchronizers – annually, that is – represent a comparatively small, but very important and effective DNA component in many transmission families made by Mercedes-Benz. In single-cone all the way to triple-cone applications, the friction systems ensure smooth shifting – although the term might suggest otherwise.
Depending on power requirements, the synchronizers are available in custom variants for three series: the TSG transmissions (Transporter-Schaltgetriebe, which literally translates as van manual transmissions) are intended for light and cargo vans, such as the V-Class, Sprinter and Vito; the NSGs (Neues Schaltgetriebe, or new manual transmission) are made for rear-wheel drive cars such as the C-, E-, S- and SLK-Classes; and in the compact front-wheel drive models of the latest A- and B-Class generation, the FSGs (Front-Schaltgetriebe, or front-wheel drive manual transmission) translate the engine's power to the desires of the driver.
KNOW-HOW FOR ZERO DEFECTS
The FSG assembly operation is based on three pillars: short distances, modern equipment, and a well-trained team. At full utilization, as is the case presently, one employee operates three stations, so things never get monotonous. Every employee could also manage the entire line though, and theoretically build the transmissions all by himself. The gear wheels and synchronizers are threaded from above – starting with the first gear and ending with the sixth – onto the vertically positioned left and right output and drive shafts. One can't help but think of pearl necklaces.
Trained eyes, high-tech cameras, and other monitoring tools at the individual stations check to ensure everything is properly seated. One important test, however, continues to be carried out manually: by briefly turning the gear wheels on the shaft to the left and right, the well-versed assembler immediately notices whether the friction systems can move freely enough, as is required for them later in the car.
Only when the employees are satisfied that the inner workings of the transmission are complete do they attach the cover – or better, the bottom half of the casing. A robot then flips everything 180 degrees and, after having applied sealing compound, adds the second casing part. Once everything has been firmly screwed together, is tight and filled with oil, things get really serious: the final, fully automatic function check reveals whether the transmission has in fact reached the high bar that Mercedes-Benz sets for function and quality. This involves shifting all the gears, recording the noise development, and also measuring the synchronization times.
The question of how HOERBIGER components typically perform in these tests is answered: they have yet to find a single HOERBIGER friction system in Rastatt that was not acceptable.