Determination of the relationship between operating effort and pin joint interference in an automobile air vent mechanism.

摘要

This thesis presents an analysis of a particular automobile air vent mechanism manufactured by Manchester Plastics Ltd. G. S. Woolley Division. In particular, it was intended to develop a mathematical model between the operating force required to regulate vanes of the automobile air vent and interference in the pin joints of the vanes, sliding friction between components in contact, as well as material properties of the components.;The Principle of Virtual Work was employed to develop a relationship that considered all joints, geometry, and materials of the air vent. Before the relationship was applied, all necessary constants and forces were obtained. Experiments were carried out to determine the coefficients of friction between the three plastic materials employed, and to obtain the force of friction between two components of the air vent. To calculate the common radius in the pin joints and in the hinge joints in both of the kinematic chains of the air vent, the Interference Model was applied. The link was modeled as a statically indeterminate two-dimensional structure, and the Finite Element Modeling Method was used to determine forces at hinge joints.;When the desired operating force is entered into the relationship, and all other factors specified, the only unknown is the interference in each of the pin joints of the second kinematic chain. The application of this relationship allows a designer to determine tolerances of mating components given a specified operating effort range.