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Unformatted text preview: type concerns the surfaces that belong to geometrical links and the second type concerns form deviations of the surfaces that do not belong to geometrical links. In order to set up the nominal situation of the components, a geometrical frame is associated to each component from given surface situations. Let us consider the assembly presented figure 1. Surfaces that belong to links are represented as points and arrows. Nominal assembly is presented on figure 1a. Figure 1b shows deviations associated to component 2 (C2) when no constrain is applied. Figure 1a Figure 1b Figure 1: Two types of deviations Section 2.1 presents how surface deviations are taken into account when 3D geometrical pairs are considered and section 2.2 presents how form deviations are determined. This model uses Small Displacement Torsor: SDT presented in [Bourdet et al, 1995] and applied in this paper to serial component assembly. 2.1. Geometrical deviation model of a geometrical pair As it is necessary to take component actual geometry into account, we propose to substitute actual surfaces that belongs to geometrical pairs by ideal surfaces that are outward tangent to actual surface. We call these surfaces substitution surfaces. The model of deviations is given using a SDT called deviation torsor, noted E [A S i /A] and presented figure 2. The six components of the deviation torsor Geometrical Study of Assembly Behaviour 303 represent position and orientation of the substitution surface relative to...
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- Spring '10
- The Land