Gearboxes on the test bench
- NOVOTEST Test Engineering

Blum-Novotest realises a large test bench project at Daimler Detroit Diesel in the USA.

Vehicle and truck gearboxes fulfil the task of converting revolutions and torque. In order to achieve the optimum relationship between low consumption and high torque, numerous factors must be observed and tested. Worldwide, the test benches of Blum-Novotest facilitate the extensive and reliable quality control of gearboxes before they are even installed.

An example in this respect is the “Global Powertrain Daimler AG” business division. For more than 20 years, the company has trusted the reliable test benches of Blum-Novotest GmbH. By now, Daimler operates more than 20 Blum-Novotest test benches worldwide. They largely concern gearbox test benches, but also drive shaft, pump or hydraulic test benches are used within the group.

Long-term partnership

Blum-Novotest is a well-known supplier in gearbox production testing. Numerous projects have already been realised in the area of truck gearbox assembly at the Gaggenau plant with its site in Rastatt. At present, there are 18 gearbox test benches of Blum-Novotest in operation only at this site. The most recent projects were realised for Daimler sites outside of Germany. Two gearbox test benches for mechanical gearboxes went into operation in India recently and later two series test benches as well as an audit test bench for truck gearboxes were delivered to the “Detroit Diesel Corporation” (DDC) a wholly owned subsidiary in Redford, USA. 

Due to the successful realisation of previous projects, Daimler took Blum-Novotest also into consideration in new test bench projects. A close relationship, between the two companies resulted in considerable profit for both parties as years went by. Blum-Novotest proved its ability of realising projects also on an international scale, for example, with test benches in India. The test benches in the USA were installed and commissioned a few months ago.

Heavy calibres

Today, heavy truck gearboxes are mainly produced at the Mercedes Benz plant in Gaggenau at its Rastatt site. In the future, the gearboxes are supposed to be assembled and tested for the American market in Redford. The “DDC” subsidiary is presently building a complete truck gearbox assembly line in that location to supply the NAFTA market from there. The demand for Daimler truck gearboxes is continually increasing so that further test benches have already been ordered.

Test bench types for truck gearboxes

Blum-Novotest has supplied two types of test benches to Redford: Series test benches and audit test benches. A series test bench serves the final inspection of the gearbox assembly. This means that the gearboxes are tested for different functions after their assembly. On the series test bench, also called End-of-Line (EoL) test bench, different torque and revolution tests are performed to ensure the high assembly quality of the gearboxes. There are fully automatic test benches but also test benches in which a worker shifts the gears manually.

Audit test benches both verify the quality of series test benches and  assume special functions. The gearboxes are put to the acid test at this point to discover any weaknesses.

The test benches differ completely in their external appearance in line with their requirements. For reasons of safety, the audit test bench in Redford is placed in a cabin of external dimensions of 13.5 m x 6 m x 3.5 m and a total weight of 23 t. The series test benches, on the other hand, are equipped with an automatic conveyor system and occupy an area of 140 m². To save space, the switchgear and electrical controls are installed on a second level. In fully automatic test benches, the only manual activities are performed prior to or after the test when the gearbox is equipped with or detached from cable sets, drive adapter, compressed air and hydraulic connections. 

The gearboxes are tested with a test system specifically developed for this purpose by Daimler to ensure the comparability of the individual test benches. After testing, the gearboxes are forwarded to the dispatch area or, in case of an assembly error, to a rework section where they are repaired and retested.

Reliability around the clock

Globally operating companies like Daimler AG make extremely high demands in terms of quality and service on their partners. Blum-Novotest has done justice to them in every respect for years: The company thus offers very fast response times as well as 24/7 service availability worldwide and this irrespective of the time zone of the customer location. In addition, the measuring and testing specialist from Germany offers, if required, commissioning support in form of a services associate trained by Blum-Novotest. Daimler makes use of this support, for example, for its test benches in India and the US in order to keep the gearbox output constantly high and to avoid any downtimes.

Blum-Novotest continuous developing its test benches in a natural manner thus permanently improving efficiency and output.  Daimler appreciates this commitment very much and intends to continue the close partnership also in future.

www.daimler.com