Patent Application
20140272317
This invention relates to adhesive joints connecting panels.
Automotive body panels are typically formed of metals, and are joined together by welding. Some body panels are formed of non-metallic composite materials, such as fiberglass, and therefore cannot be welded. Composite panels are typically joined together with adhesive applied to mating flanges.
A first panel defines a first surface characterized by a first base portion and a protuberance extending from the first base portion. A second panel defines a second surface having a second base portion and a depression. The protuberance extends into the depression, and adhesive is disposed on the first base portion, the protuberance, the second base portion, and in the depression, to bond the first panel to the second panel. The protuberance and surface defining the depression provide regions of shear when the base portions are in peel, thereby increasing the strength of the adhesive joint between the first and second panels.
A corresponding method of joining two panels is also provided.
The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
Referring to
The first flange 10 of the first panel 18 defines a first surface 26 characterized by a first base portion 30. The first base portion 30 in the embodiment depicted is substantially planar. The first surface 26 also defines a plurality of protuberances 34 extending from the first base portion 30. The second flange 14 of the second panel 22 defines a second surface 38 facing the first surface 26.
Referring to
Referring to
The second flange 14 defines a third surface 72 that is on the opposite side of the second flange 14 from the second surface 38. In the embodiment depicted, the depth of the depressions 58 is greater than the thickness of the flange 14, and thus there is a frusto-pyramidal protuberance (shown at 74 in
Referring to
For each protuberance 34, each of the surface portions 42, 44, 46, 48, 52 is parallel with, and directly bonded via the adhesive 76 to, a corresponding surface portion 60, 62, 64, 66, 68 defining one of the depressions 58. More specifically, as shown in
Surface portions 42, 44, 46, 48, 52 are all in different planes from each other and from the first base portion 30, and none of surface portions 42, 44, 46, 48 are parallel to each other or to the base portion 30. Similarly, surface portions 60, 62, 64, 66, 68 are all in different planes from each other and from the second base portion 54, and none of surface portions 60, 62, 64, 66 are parallel to each other or to the base portion 54.
Accordingly, the protuberances 34 and the depressions 58 add several surface portions in differing planes that have adhesive 76 thereon, and thus add some shear loaded adhesive in directions that might normally be purely in peel when a stress is applied to the panels 18, 22. Adhesive 76 may be significantly stronger in shear than in peel, and thus the protuberances 34 and depressions 58 strengthen the bond between the first and second panels 18, 22 by creating regions of shear stress that would otherwise be in peel. When the adhesive 76 between the base portions 30, 54 is in peel, adhesive 76 between the protuberances 34 and the depressions 58 may be in shear. Thus, the adhesive joint 75 may eliminate a need for mechanical fasteners (such as nuts and bolts) to resist peel forces. The protuberances 34 and the depressions 58 also provide a mechanical interlock between the flanges 10, 14 along the plane of the joint 75.
Referring again to
Referring to
The first flange 110 of the first panel 118 defines a first surface 126 characterized by a first base portion 130. The first base portion 130 in the embodiment depicted is substantially planar. The second flange 114 of the second panel 122 defines a second surface 134 facing the first surface 126. The second surface 134 is characterized by a second base portion 136, which is substantially planar.
The first surface 126 also defines a plurality of protuberances 138 extending from the first base portion 130. The protuberances 138 are spherical caps, i.e., the protuberances form spheres that are cut by a plane. In the embodiment depicted, the protuberances 138 are hemispheres. The second surface 134 also includes surface portions 140 that define a plurality of depressions 142, which, in the embodiment of
An adhesive joint 174 bonding the first and second flanges 110, 114 is formed by applying an adhesive 176 to one of the first surface 126 and the second surface 134, and then positioning the first panel 118 with respect to the second panel 122 such that each of the protuberances 138 extends into a respective one of the depressions 142, as shown in
The surface of each protuberance 138 is parallel with a respective surface portion 140 defining a respective depression 142; adhesive 176 also extends therebetween to bond the protuberances 138 to the surface portions 140. Accordingly, the protuberances 138 and the depressions 142 add several surface portions in differing planes that have adhesive 176 thereon, and thus add some shear loaded adhesive in directions that might normally be purely in peel when a stress is applied to the panels 118, 122.
It should be noted that the fit between protuberances 34 and depressions 58, and the fit between protuberances 138 and depressions 142, are clearance fits, rather than interference fits. In the embodiments depicted, the protuberances and depressions are shown as either frustums of pyramids or spherical caps; however, protuberances and depressions may have other shapes within the scope of the claimed invention. It should also be noted that, as used in the claims, a “depression” may include a hole that extends through a panel from one side to the other. In one embodiment (not shown), and within the scope of the claimed invention, the depressions are cylindrical holes and the protuberances are cylindrical knobs.
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.
