Patent Publication Number: US-2021180629-A1

Title: Alignment feature for an elastic averaging alignment system

Description:
INTRODUCTION 
     The present invention generally relates to a method of manufacturing an assembly for a vehicle, and more specifically to a method of using an average elastic deformation of elastically deformable features to secure and align a first member and a second member. 
     Currently, components, such as those found in motor vehicles and other manufactured vehicle items, as well, as those found in non-motor vehicle manufactured items, are mated together in a process and are mutually located with respect to each other by alignment features that are sized to provide spacing to freely move the components relative to one another to align them without creating an interference therebetween that would hinder the manufacturing process. There is a clearance between the male alignment features and their respective female alignment features which is predetermined to match anticipated size and positional variation tolerances of the male and female alignment features as a result of manufacturing (or fabrication) variances. As a result, significant positional variation can occur between the mated first and second components having the aforementioned alignment features, which may contribute to the presence of undesirably large variation in their alignment, particularly with regard to the gaps and spacing between them. When such misalignment occurs, it can negatively affect function and result in a perception of poor quality. 
     Thus, while current assemblies achieve their intended purpose, there is a need for a new and improved system and method for assembling two components. 
     SUMMARY 
     A method of assembly according to the present disclosure includes forming a first member to include a plurality of elastically deformable locating protrusions extending outward from an exterior surface of the first member. A respective locating protrusion of the plurality of locating protrusions is an elongate member having, in cross section, an arcuate portion extending from a first arc end to a second end, a first linear leg portion extending from the first arc end to a first free end, and a second leg portion extending from the second arc end to a second free end. The method additionally includes forming a second member to include a plurality of elastically deformable compression features. The method further includes inserting the plurality of locating protrusions in press fit engagement with the plurality of compression features such that the first member and the second member are secured relative to each other and the average of the elastic deformation between all of the plurality of locating protrusions and all of the plurality of compression features precisely aligns the first member relative to the second member. 
     In various embodiments, the first linear leg portion is parallel or not parallel to the second linear leg portion. 
     In an exemplary embodiment, the arcuate portion includes an outer periphery provided with at least one retention tab. 
     In an exemplary embodiment, forming the first member includes forming the plurality of locating protrusions integrally with the first member from a common material, which may be a polymeric material. 
     An assembly according to the present disclosure includes a first member and a second member. The first member has a first surface and a plurality of elastically deformable locating protrusions extending outward from an exterior surface of the first member. A respective locating protrusion of the plurality of locating protrusions is an elongate member having, in cross section, an arcuate portion extending from a first arc end to a second end, a first linear leg portion extending from the first arc end to a first free end, and a second leg portion extending from the second arc end to a second free end. The second member has a plurality of elastically deformable compression features. Respective protrusions of the plurality of locating protrusions are in press fit engagement with the plurality of compression features such that the first member and the second member are secured relative to each other and the average of the elastic deformation between all of the plurality of locating protrusions and all of the plurality of compression features precisely aligns the first member relative to the second member. 
     In a first exemplary embodiment, the first linear leg portion is parallel to the second linear leg portion. In a second exemplary embodiment, the first linear leg portion is not parallel to the second linear leg portion. 
     In an exemplary embodiment, the arcuate portion includes an outer periphery provided with at least one retention tab. 
     In an exemplary embodiment, the plurality of locating protrusions are integral with and have a common material composition with the first member. The common material composition may include a polymeric material. 
     An automotive vehicle according to the present disclosure includes a first component and a second component. The first component has a first surface and a plurality of elastically deformable locating protrusions extending outward from an exterior surface of the first component. A respective locating protrusion of the plurality of locating protrusions is an elongate component having, in cross section, an arcuate portion extending from a first arc end to a second end, a first linear leg portion extending from the first arc end to a first free end, and a second leg portion extending from the second arc end to a second free end. The second component has a plurality of elastically deformable compression features. Respective protrusions of the plurality of locating protrusions are in press fit engagement with the plurality of compression features such that the first component and the second component are secured relative to each other and the average of the elastic deformation between all of the plurality of locating protrusions and all of the plurality of compression features precisely aligns the first component relative to the second component. 
     In a first exemplary embodiment, the first linear leg portion is parallel to the second linear leg portion. In a second exemplary embodiment, the first linear leg portion is not parallel to the second linear leg portion. 
     In an exemplary embodiment, the arcuate portion includes an outer periphery provided with at least one retention tab. 
     In an exemplary embodiment, the plurality of locating protrusions are integral with and have a common material composition with the first component. The common material composition may include a polymeric material. 
     Embodiments according to the present disclosure provide a number of advantages. For example, the present disclosure provides an elastic averaging assembly capable of providing desired stiffness characteristics in conjunction with a larger slot, and moreover does so while maintaining acceptable overall dimensions. 
     The above advantage and other advantages and features of the present disclosure will be apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed examples will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
         FIG. 1  is a top view of a prior art elastic averaging assembly; 
         FIG. 2  is a first isometric top view of an elastic averaging assembly according to an embodiment of the present disclosure; 
         FIG. 3  is a second isometric top view of an elastic averaging assembly according to an embodiment of the present disclosure; 
         FIG. 4  is a third isometric top view of an elastic averaging assembly according to an embodiment of the present disclosure; 
         FIG. 5  is a view along section A-A in  FIG. 2 ; and 
         FIG. 6  is a top view depicting alternative arrangements for elastic averaging assemblies according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations. 
     Referring now to  FIG. 1 , a known elastic averaging assembly  10  is shown. The assembly  10  includes a first component  12  and a second component  14 . The first component  12  includes an elongate member with a generally arcuate profile. The first component  12  is inserted through a slot  16  of the second component  14  to join or mate the two components together. The first component  12  is oversized relative to the slot  16  such that as the first component  12  is inserted into the slot  16 , the first component  12  and second component  14  elastically deform for elastic averaging coupling between the components  12 ,  14 . 
     However, for some configurations and/or materials, known elastic averaging assemblies may provide packaging challenges. As an example, some materials have manufacturing tolerances which require relatively large slots, e.g. with a width greater than approximately 2.5 mm. As used herein, width refers to the smallest dimension of the slot. Known elastic averaging profiles, e.g. the arcuate profile illustrated in  FIG. 1 , would become undesirably wide and/or stiff when scaled to fit in slots of such widths. 
     Referring now to  FIGS. 2-5 , an elastic averaging assembly  20  is shown according to an embodiment of the present disclosure. The assembly  20  includes a first component  22  and a second component  24 . While only one first component  22  and one second component  24  are illustrated herein, the assembly  20  may comprise a plurality of first components  22  and second components  24 . Elastic averaging represents a subset of surface coupling types where improved accuracy is derived from the averaging of error over a large number of contacting surfaces. Elastic averaging is based on significantly over-constraining a solid body with a large number of relatively compliant members. As the components are preloaded, the elastic properties of the components allow for the size and position error of each individual contact feature to be averaged out over the sum of contact features throughout the solid body. In a well-designed and preloaded elastic averaging coupling, the repeatability is approximately inversely proportional to the square root of the number of contact points. 
     The first component  22  defines an elongate member extending from a body  23 . In an exemplary embodiment, the first component  22  and body  23  are integrally formed of a common material, e.g. a polymeric material. However, in other embodiments, the first component  22  and body  23  may be formed of separate materials. The body  23  may be a generally planar body as illustrated in  FIG. 5 , or may take any other suitable shape according to the desired configuration. In an exemplary embodiment, the second component  24  comprises metal, e.g. sheet metal. However, in other embodiments the second component  24  may be formed of other materials. The second component  24  may be a generally planar body as illustrated in  FIG. 5 , or may take any other suitable shape according to the desired configuration. 
     The first component  22  has a profile with an arcuate portion  28  extending from a first arc end  30  to a second arc end  32 . A first linear leg portion  34  extends from the first arc end  30 , and a second linear leg portion  36  extends from the second arc end  32 . In the illustrated embodiment the leg portions  34 ,  36  are parallel with one another; however, in other embodiments the leg portions  34 ,  36  are not parallel, as will be discussed in further detail below. In the illustrated embodiment the arcuate portion  28  is provided with at least one retention tab  38  on an outer surface thereof; other embodiments, however, may omit such a feature. 
     The first component  22  is inserted through a slot  26  of the second component  24  to join or mate the two components together. In the illustrated embodiment, the second component  24  is provided with a flange  27  extending from a lower surface  25  of the second component  24  about the periphery of the slot  26 . In such an embodiment, the flange  27  may guide the first component  22  to a desired position and orientation relative to the slot  26  and facilitate insertion thereto. However, other embodiments may omit the flange  27 . 
     The first component  22  is oversized relative to the slot  26  such that as the first component  22  is inserted into the slot  26 , an interference occurs between the arcuate portion  28  and the slot  26 . Upon further insertion, the first component  22  and second component  24  elastically deform for elastic averaging coupling between the components  22 ,  24 . Upon full insertion, the retention tab  38  engages with the slot  26 , e.g. via the flange  27 , to secure the first and second components in the desired position relative to one another. 
     While  FIGS. 2-5  depict the leg portions  34 ,  36  as parallel, in other embodiments the leg portions  34 ,  36  may be provided in a non-parallel configuration. As shown in  FIG. 6 , legs  34 ′,  36 ′ may be provided in a non-parallel orientation. In such embodiments, the cant angle of the legs  34 ′,  36 ′ relative to the arcuate portion  28  may be selected to provide a desired stiffness characteristic of the first component  22 . 
     As may be seen, the present disclosure provides an elastic averaging assembly capable of providing desired stiffness characteristics in conjunction with a larger slot, and moreover does so while maintaining acceptable overall dimensions. 
     As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications.