Low Loss Articulated Hauler Axle : A Conceptual Study

Abstract: Volvo Construction Equipment is highly regarded for robust products, but with an increasing competition in their market, development of the product portfolio is more important than ever. One step being carried out is to reduce losses in powertrains and increase the fuel efficiency for solutions such as articulated haulers and wheel loaders. This would eventually lower the fuel costs and emissions for the end customer. With this development, Volvo CE could strengthen their position in the market while also contributing to reducing the construction industry's environmental impact. By investigating the front bogie axle of the recently introduced hauler, Volvo A60H, important information about possible reductions and the distribution of the current losses were found. The investigation focused on a front bogie axle, but some of the results are applicable for other applications such as wheel loaders as well, since a lot of the technology in the axles are similar. A conceptual study was performed where completely new ideas were generated, such as implementing a dry sump system in the axle, as well as ideas for improving the subcomponents currently found in the axle. Two cases were presented for the evaluation of concepts, one with a fully loaded dump body and low speeds, and one with an unloaded dump body and a wider speed interval. The concepts were later evaluated using calculation tools such as MATLAB and a Simulink-model was created for the losses in the axle. When combining concepts that reduces load dependent losses, a potential reduction of 64% of the axle's total losses was achieved for the case with a full dump body. The largest improvement found for the load independent losses was 8% with an unloaded hauler and the highest speed investigated, 50 km/h. A dry sump system improves the axle's efficiency with 45% in optimal working conditions, but was found to lower the efficiency at other conditions. Room for improvement of axle losses currently exists both for load dependent and load independent losses. The evaluation performed pointed towards the load dependent losses being the largest influence on the total losses, even with an unloaded dump body and high speeds. This is an interesting observation since a lot of work at Volvo CE has revolved around reducing the load independent losses since these are easier to affect with different lubrication levels and rotational speeds. A test methodology for load dependent losses should be implemented in order to validate the results of this thesis work, and also to aid further development at Volvo CE.