Patent Application
20150174740
The present invention relates to matable components, and more particularly to an elastic retaining assembly for such matable components, as well as a method of assembling matable components.
Currently, components which are to be mated together in a manufacturing process are subject to positional variation based on the mating arrangements between the components. One common arrangement includes components mutually located with respect to each other by 2-way and/or 4-way male alignment features; typically undersized structures which are received into corresponding oversized female alignment features such as apertures in the form of openings and/or slots. Alternatively, double-sided tape, adhesives or welding processes may be employed to mate parts. Irrespective of the precise mating arrangement, there is a clearance between at least a portion of the alignment features which is predetermined to match anticipated size and positional variation tolerances of the mating features as a result of manufacturing (or fabrication) variances. As a result, occurrence of significant positional variations between the mated components is possible, which may contribute to the presence of undesirably large and varying gaps. The clearance between the aligning and attaching features may lead to relative motion between mated components, which contribute to poor perceived quality. Additional undesirable effects may include squeaking and rattling of the mated components, for example.
In an exemplary embodiment, an elastic retaining assembly for matable components includes a first component having a first surface. Also included is a second component having a first surface and a second surface, the second component configured to be mated with the first component in a fully engaged position. Further included is a receiving feature extending through the second component, the receiving feature defining a wall. Yet further included is a protrusion operatively coupled to, and extending away from, the first surface, wherein the protrusion is formed of an elastically deformable material and configured to elastically deform upon contact with the wall of the receiving feature, wherein the protrusion retains the first component to the second component in a first direction in the fully engaged position. Also included is a retention member located at a first end of the protrusion and extending radially from the first end of the protrusion, the retention member formed of the elastically deformable material, wherein the retention member is configured to abut the second surface of the second component and be rotated to retain the first component to the second component in a second direction that is substantially perpendicular to the first direction in the fully engaged position.
In another exemplary embodiment, a method of assembling matable components is provided. The method includes inserting an elastically deformable protrusion of a first component into a receiving feature of a second component, wherein a contact interference condition between the elastically deformable protrusion and a wall of the receiving feature retains the elastically deformable protrusion in a first direction. The method also includes elastically deforming the elastically deformable protrusion upon contacting the wall of the receiving feature. The method further includes rotating the elastically deformable protrusion with a first wing portion extending radially away from a central axis of the elastically deformable protrusion and a second wing portion extending radially away from the central axis in a first radial direction, wherein the second wing portion is angled about 180 degrees from the first radial direction. The method yet further includes retaining the first component to the second component in a second direction that is substantially perpendicular to the first direction upon rotating the elastically deformable protrusion into a fully engaged position.
The above features and advantages and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.
Other features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which:
Referring to
Although illustrated in a specific geometry, the first component 12 and the second component 14 may be configured in countless geometries. Regardless of the precise geometry of the first component 12 and the second component 14, the first component 12 is configured to align and fittingly mate with the second component 14, which will be described in detail below. In an alternative embodiment, rather than two components comprising the elastic retaining assembly 10, additional or intermediate layers or components may be included. It is to be appreciated that the elastic retaining assembly 10 is to be employed for providing a self-aligning relationship between components, such as the first component 12 and the second component 14, to each other, while also assisting in securely mating the components to each other.
The first component 12 includes a main portion 16 having a first surface 18 that is typically a substantially planar surface. In the illustrated embodiment, the first surface 18 is to be disposed in close proximity to a first surface 19 of the second component 14 when the components are mated in a fully engaged position. The second component 14 also includes a second surface 21. The first component 12 also includes a protrusion 20 extending from the main portion 16 in a direction relatively orthogonal from a plane that the first surface 18 is disposed in. The protrusion 20 is operatively coupled to the main portion 16 and may be integrally formed with the main portion 16. The protrusion 20 includes a main body 22 extending from the first surface 18 to a second end 24. The second component 14 includes a receiving feature 26 in the form of a cutout slot portion that is configured to engage and receive the protrusion 20 upon mating of the first component 12 and the second component 14. Specifically, the protrusion 20 is inserted into the receiving feature 26 in a direction 40. Although a single protrusion and a single receiving feature are referenced, embodiments of the elastic retaining assembly 10 may include a plurality of protrusions and a plurality of receiving features, as will be described in detail below.
The protrusion 20 and the receiving feature 26 may be formed as numerous contemplated complimentary embodiments. In the exemplary embodiment, the main body 22 of the protrusion 20 is formed as a relatively tubular member and it is to be appreciated that the main body 22 may comprise a solid cylindrical member or a tubular member having a hollow portion. Further, numerous alternative geometries may form the main body 22 of the protrusion.
As will be apparent from the description herein, the elastically deformable nature of the protrusions, in combination with the particular orientations described above, facilitates precise alignment of the first component 12 relative to the second component 14 by accounting for positional variation of the retaining and/or locating features of the first component 12 and the second component 14 inherently present due to manufacturing processes. The self-aligning benefits associated with the elastic retaining assembly 10 will be described in detail below.
The main body 22 of the protrusion 20 of the first component 12 is positioned and engaged with the receiving feature 26 of the second component 14 upon translation of the first component 12 toward the second component 14 (or vice versa). More particularly, a protrusion perimeter surface 30 of the main body 22 engages an aperture wall 32. Subsequent translation results in an elastic deformation of the main body 22. Specifically, the main body 22 includes a protrusion width 33 that is greater than an aperture width 34, thereby ensuring contact between the protrusion perimeter surface 30 and the aperture wall 32 of the receiving feature 26. Elastic deformation of the main body 22 may be further facilitated by embodiments comprising a hollow protrusion, as illustrated. The void of material proximate the hollow portion enhances the flexibility of the protrusion 20. Regardless of whether the protrusion 20 is solid or hollow, the main body 22 is further translated along the aperture wall 32.
Any suitable elastically deformable material may be used to construct the protrusion 20. The term “elastically deformable” refers to components, or portions of components, including component features, comprising materials having a generally elastic deformation characteristic, wherein the material is configured to undergo a resiliently reversible change in its shape, size, or both, in response to application of a force. The force causing the resiliently reversible or elastic deformation of the material may include a tensile, compressive, shear, bending or torsional force, or various combinations of these forces. The elastically deformable materials may exhibit linear elastic deformation, for example that described according to Hooke's law, or non-linear elastic deformation.
Numerous examples of materials that may at least partially form the components include various metals, polymers, ceramics, inorganic materials or glasses, or composites of any of the aforementioned materials, or any other combinations thereof. Many composite materials are envisioned, including various filled polymers, including glass, ceramic, metal and inorganic material filled polymers, particularly glass, metal, ceramic, inorganic or carbon fiber filled polymers. Any suitable filler morphology may be employed, including all shapes and sizes of particulates or fibers. More particularly any suitable type of fiber may be used, including continuous and discontinuous fibers, woven and unwoven cloths, felts or tows, or a combination thereof. Any suitable metal may be used, including various grades and alloys of steel, cast iron, aluminum, magnesium or titanium, or composites thereof, or any other combinations thereof. Polymers may include both thermoplastic polymers or thermoset polymers, or composites thereof, or any other combinations thereof, including a wide variety of co-polymers and polymer blends. An example of a suitable polymer includes acetal (e.g., POM). In one embodiment, a preferred plastic material is one having elastic properties so as to deform elastically without fracture, as for example, a material comprising an acrylonitrile butadiene styrene (ABS) polymer, and more particularly a polycarbonate ABS polymer blend (PC/ABS), such as an ABS acrylic. The material may be in any form and formed or manufactured by any suitable process, including stamped or formed metal, composite or other sheets, forgings, extruded parts, pressed parts, castings, or molded parts and the like, to include the deformable features described herein. The material, or materials, may be selected to provide a predetermined elastic response characteristic of the protrusion 20. The predetermined elastic response characteristic may include, for example, a predetermined elastic modulus and/or coefficient of friction.
The precise position where engagement between the protrusion perimeter surface 30 and the aperture wall 32 of the receiving feature 26 occurs will vary depending on positional variance imposed by manufacturing factors. Due to the elastically deformable properties of the elastic material comprising the protrusion 20, the criticality of the initial location of engagement is reduced. Further insertion of the main body 22 into the receiving feature 26 ultimately leads to a fully engaged position of the main body 22. In the fully engaged position, a tight, fitted engagement between the main body 22 and the receiving feature 26 is achieved by contact interface between the protrusion perimeter surface 30 and the aperture wall 32. Such a condition is ensured by sizing the protrusion perimeter, width or other dimension to be larger than a retaining feature dimension (e.g., width). In the fully engaged position, the protrusion 20 retains the first component 12 to the second component 14 in a first direction 37.
The interference between the main body 22 and the aperture wall 32 causes elastic deformation proximate protrusion perimeter surface 30. The malleability of the materials reduces issues associated with positional variance. More particularly, in contrast to a rigid insert that typically results in gaps between the insert and receiving structure at portions around the perimeter of the insert, the main body 22 advantageously deforms to maintain alignment of the first component 12 and the second component 14, while also reducing or eliminating gaps associated with manufacturing challenges. The assembly also advantageously reduces the number of mechanical fasteners, such as threaded fasteners required for attachment of the components, thereby reducing cost and component degradation.
The first component 12 may include a plurality of protrusions 20, while the second component 14 may include a plurality of receiving features 26. The plurality of receiving features is positioned to correspondingly receive respective protrusions in a manner described in detail above. The elastic deformation of the plurality of protrusions elastically averages any positional errors of the first component 12 and the second component 14. In other words, gaps that would otherwise be present due to positional errors associated with portions or segments of the first component 12 and the second component 14, particularly locating and retaining features, are eliminated by offsetting the gaps with an over-constrained condition of other elastically deformable protrusions. Specifically, the positional variance of each protrusion and/or receiving feature is offset by the remaining protrusions to average in aggregate the positional variance of each protrusion.
Elastic averaging provides elastic deformation of the interface(s) between mated components, wherein the average deformation provides a precise alignment, the manufacturing positional variance being minimized to Xmin, defined by Xmin=X/√N wherein X is the manufacturing positional variance of the locating features of the mated components and N is the number of features inserted. To obtain elastic averaging, an elastically deformable component is configured to have at least one feature and its contact surface(s) that is over-constrained and provides an interference fit with a mating feature of another component and its contact surface(s). The over-constrained condition and interference fit resiliently reversibly (elastically) deforms at least one of the at least one feature or the mating feature, or both features. The resiliently reversible nature of these features of the components allows repeatable insertion and withdrawal of the components that facilitates their assembly and disassembly. In some embodiments, the elastically deformable component configured to have the at least one feature and associated mating feature disclosed herein may require more than one of such features, depending on the requirements of a particular embodiment. Positional variance of the components may result in varying forces being applied over regions of the contact surfaces that are over-constrained and engaged during insertion of the component in an interference condition. It is to be appreciated that a single inserted component may be elastically averaged with respect to a length of the perimeter of the component. The principles of elastic averaging are described in detail in commonly owned, co-pending U.S. patent application Ser. No. 13/187,675, now U.S. Publication No. U.S. 2013-0019455, the disclosure of which is incorporated by reference herein in its entirety. The embodiments disclosed above provide the ability to convert an existing component that is not compatible with the above-described elastic averaging principles, or that would be further aided with the inclusion of an elastically averaged alignment and retention system as herein disclosed, to an assembly that does facilitate elastic averaging and the benefits associated therewith.
With continued reference to
The retention member 50 extends radially from a central axis 52 of the main body 22 of the protrusion 20. In particular, the retention member 50 includes a first wing portion 54 extending radially away from the central axis 52 in a first radial direction 60 and a second wing portion 58 extending radially away from the central axis 52 in a second radial direction 56 that is shown oppositely disposed from the first radial direction 60. In other words, the second wing portion 58 is shown angled about 180 degrees from the first wing portion 54. However, it is to be understood that the relative angular orientation between the first wing portion 54 and the second wing portion 58 may be any alternative angle from that shown. As shown, the first wing portion 54 and the second wing portion 58 combine to form a propeller-like member. The propeller wings have clearance to the second component aperture 26 as the protrusion is initially inserted into the receiving feature (
Although the retention member 50 is illustrated and described herein as having two wing portions, it is to be appreciated that a single wing portion, such as the first wing portion 54 or the second wing portion 58, may be employed. Although the wing portions are shown as being longer than protrusion diameter 33 it is to be appreciated that the wing portion 54 or 58 may be relatively short with a length less than the diameter of the protrusion 20.
Referring now to
Reference is now made to
It is contemplated that depressions, grooves, or the like are formed in the second surface 21 of the second component 14. Such an embodiment may replace the need for ramps 64, as the wing portions of the retention member 50 are rotated until they are dropped into, or engage, the feature of the second surface 21.
Irrespective of the particular feature (e.g., ramps, depressions) employed to retain the wing portions of the retention member 50, it is to be appreciated that the angle of rotation that the retention member 50 must undergo to achieve the fully engaged position will vary. In particular, although the degree of rotation appears to be about 90 degrees in the illustrated embodiments described above, a range of about 20 degrees to about 90 degrees is considered suitable depending on the location and dimensions of the retaining feature.
Referring now to
As shown in
A method 100 of assembling matable components is also provided, as illustrated in
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the application.
