Analys och utveckling av boggi till ramstyrd dumper
Volvo Construction Equipment is one of the worlds largest manufacturer of heavymachinery. In Braås, Sweden, they develop and manufacture articulated haulers inseveral sizes. The biggest, the A40, is capable of loading almost 40 metric tonnes.These haulers have a bogie to distribute the forces of the load evenly onto the two axlesand there wheels. The bogie is constructed using a rigid balance beam on each side ofthe frame connecting the axles or an independent solution using hydropneumatics.An analysis has been made in order to establish the forces created during corneringand through the theory, an estimation of the extensive tyre wear and extra fuelconsumption has been made. All due to the effects of the tyres not being inline with thecornering radius. Instead the wheels are turning around a point in the extension of thebogie center.Three ideas of concepts has been suggested and evaluated and two of these ideas hasshown great potential in solving the problem satisfactory. The main feature of the ideasare to either control the entire rear bogie axle or to control the rear wheelsindependently. Both solutions make use for hydraulic motors instead of conventionaldriveshafts. It will provide sufficient power in low speeds and has small deficienciesduring higher speeeds.In the analysis a driving cycle is produced from driving a hauler on a test ground. Itshows that barely 5% of steering angles are above 30 degrees. From this driving cycleand from the theory a net savings of 141000 SEK are made calculating a 10% decreasein tyre wear and a 1% decrease in fuel consumption throughout a 12000 hour session.This sum is to be divided between machine owner, retailer, Volvo CE and potentiallyincreased production cost.