The Systematic Development Process Applied on a Cab Rotation Unit : Pre-study, concept generation, embodiment design, material selection and optimization

Abstract: This master thesis studies and applies the systematic development process. The process is initially described in general, creating a template for the process, and later on applied on a real case scenario to show the performance. Finally eventual advantages, drawbacks and suggestions for future improvements are given. The systematic development approach has been performed at Laxå Special Vehicles, who produce truck cabs and special truck chassis for Scania CV AB. The project has focused on the cabs, i.e. the Crew Cabs and the Low Entry. Crew Cabs are extended normal truck cabs, containing four doors to make additional passengers possible, suitable for fire trucks etc. Low Entry is a lowered normal truck cab, lowering the approaching height, making this cab type suitable for city applicable usage where the driver or passengers enter and leave the cab frequently. The task given was to develop the current cab rotation unit to be able to handle both cabs, which from the beginning only could handle the Crew Cabs, called CC28 and CC31. The major goal of this project has been to enable rotation of the Low Entry too. Five phases – pre-study, concept generation, embodiment design, material selection and optimization – were carried out. The pre-study generated a fundamental base of knowledge, according to both the systematic development process and information about the tilt. The concept generation contained a problem degradation, generation of possible solutions and finally an evaluation of these. During the embodiment design the best suited concept was described and developed in detail to allow a suitable material to be selected during the material selection phase. The optimization process consisted of investigating properties according to mechanical strength and stiffness. Two construction solutions to accommodate the mounting points height and length difference between the Crew Cab and the Low Entry were developed. These were a covering plate, called K4, and a mounting plate, called K100, handling the problems occurring for length and height respective. The development process is thus considered to be well operating. It generated a useful result, although possibilities for further improvements exists.