Utveckling av en fördelningsväxellåda till hjullastare

Sammanfattning: The thesis is a case study on the construction of a dropbox for wheel loaders. The thesis was carried out at Volvo Construction Equipment (VCE) who is one of the leading manufacturers of construction equipment. The data collection consisted of a pre-study, a literature review, and simulations and calculations, which was done at VCE. This led to the use of both primary and secondary data, as well as quantitative and qualitative data. The purpose of the thesis was to construct a dropbox which could be combined with a gearbox, for it to work in a wheel loader. The gearbox was a planetary gearbox used in articulated haulers and only some smaller adjustments were to be made on the gearbox. Part of the thesis was to investigate the possibilities to use a hydraulic or electric system in combination with the dropbox. This was to improve the fit of the planetary gearbox to the wheel loader and possibly improve the environmental impact from the wheel loader. The research questions in the thesis were: F1: How can a dropbox be constructed to enable a gearbox fitted for articulated haulers to work in wheel loaders? F2: What are the possibilities to affect the overall cost of the transmission and the environmental impact of the wheel loader with the construction of a dropbox? F3: Which outcomes regarding manufacturing and sales would occur when a articulated hauler and a wheel loader uses the same planetary gearbox? F4: What general factors can be identified to make a modular completion of a existing gearbox, to create a gearbox for better manufacturing and aftermarket management? The method that was used was a combination of Ullman’s and Ulrich and Eppinger’s product development processes. The work was divided in four general phases: planning, information gathering, concept generation, and further development. Appropriate techniques were used to ensure that every phase was completed. The result was a suggestion of a construction of a dropbox. This dropbox was to be combined with a planetary gearbox for articulated haulers to be adjusted to fit the wheel loader model L350. Six gears were chosen from the planetary gearbox for driving both forward and backward. The construction of the dropbox consisted of a cog chain which distributes the driving force and shift elements which changes the direction. The energy which the shift elements were to dissipate was calculated and the dimensions of the cogwheels in the cog chain were estimated. A CAD-model was made to generate an image of the concept. Important factors for the conclusive result included which gears that was used and how they were used. This is a result of the different driving cycles the working machines have, since the driveline has to be adjusted for every machine. A complementary system was an important factor regarding cost and environmental impact. However, it was shown to be hard to implement because of the wide range of the rotational speed in which the complementary motor had to work. Further investigations are required regarding the choice of torque converter, construction of power take-out for the work hydraulic, integration of a complementary system, and the construction of the dropbox case.