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This study deals with the design of variable displacement oil pumps, with particular focus on wear of the inner components. A multibody model has been developed in order to achieve detailed knowledge on the dynamic loads which the main components are subjected to and to carry out a comparative analysis between different pump designs. A qualitative correlation, between the resulting wear following endurance tests and simulation results, has also been found. Design guidelines leading up to a good pump reliability have been obtained as a result of this activity.

A ride comfort analysis of two-wheeled veichles is discussed in this work. A series of experimental tests were performed in relation to roads having different surface roughness; employed vehicles, differing on motorization, suspensions and wheel sizes, were instrumented with two axes (longitudinally and vertically oriented) accelerometers, fixed at the human-vehicle interfaces. Moreover, two axes accelerometers were also fixed to the wheel hubs, in order to record road inputs at each wheel. The comfort analysis, which was conducted following the international ISO 2631, allowed the influence of the primary vehicle suspension system to be investigated. In addition, a multibody model of the scooter-pilot system was built using Adams© code, for one of the employed vehicles, with the main aim of assessing the effectiveness of a dynamic simulation of ride comfort.

In the present paper a theoretical model for the analysis of compound crank axle is presented. It is based on the set of equilibrium, constitutive and congruence equations of the axle; to this aim, the cross-member is described by its stiffness matrix, the longitudinal arms are assumed as rigid and the bearing which connects the axle to the body as ideal. For this configuration, a closed form solution for the elastokinematic analysis is obtained in the small displacements field, for the pure roll condition. This can be summarized by the knowledge of the position, in a 3D space, of the instantaneous axis of rotation of each wheel; it is shown how the instantaneous axis of rotation is determined by both the axle geometry and the stiffness properties of the cross member. An iterative procedure has been also developed for the large displacement analysis. Results, in terms of camber and toe angle alteration, are discussed in comparison with those obtained by finite element analyses.