Patent Application
20100276047
The technical field generally relates to wheel rims and tires, and to interfaces between wheel rims and tires.
Automotive tire and wheel assemblies often include a tire mounted on a wheel rim. The tire commonly has a bead portion that forms an air-tight seal at an interface with a flange of the wheel rim. The tire also commonly has a chafer portion contacting the flange at the interface to help prevent chafing to the tire at the interface.
One exemplary embodiment includes a product which may include a wheel having a wheel rim, and may include a wear resistant coating. The wheel rim may comprise magnesium. The wheel rim may have one or more flange(s) that are constructed and arranged in order to seat a bead portion of an associated tire mounted to the wheel rim. The wear resistant coating may be located over the flange(s) on at least a part of a section of the flange(s) that opposes the bead portion of the tire when the tire is mounted to the wheel rim.
One exemplary embodiment includes a method which may include providing a wheel which may have a wheel rim that itself may comprise magnesium. The wheel rim may have a flange that is constructed and arranged in order to seat a bead portion of an associated tire when the tire is mounted to the wheel rim. The method may also include applying a wear resistant coating over the flange on at least a part of a section of the flange that opposes the bead portion of the tire when the tire is mounted to the wheel rim.
One exemplary embodiment includes a product which may include a tire, a wheel, and a wear resistant coating. The tire may have a first bead portion and a second bead portion. The wheel may have a wheel rim. The wheel rim may have a first flange and a second flange. The first flange may be constructed and arranged to seat the first bead portion, and the second flange may be constructed and arranged to seat the second bead portion. The wear resistant coating may be located at an interface between the first flange and the first bead portion, and between the second flange and the second bead portion.
Other exemplary embodiments of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Exemplary embodiments of the invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the embodiment(s) is merely exemplary (illustrative) in nature and is in no way intended to limit the invention, its application, or uses.
The figures illustrate an exemplary embodiment of a wear resistant coating 10 used with a tire and wheel assembly 12 of an associated automobile. The wear resistant coating 10 may help prevent abrasion, damage, and wear that may otherwise occur between the tire and wheel assembly 12 due to repeated vibration, rolling, sliding, and other movement. Though described in the context of an automobile, the wear resistant coating 10 may be used with tire and wheel assemblies of motor homes, trailers, semi-trailer trucks, and the like.
Referring to
Referring to
The wheel 16 may carry the tire 14 and may connect to other components of the associated automobile. The wheel 16 may have a wheel rim 42 and a wheel disc 44. The wheel rim 42 and the wheel disc 44 may be a one-piece structure, as shown, or may be separate pieces that are connected together. The wheel rim 42 may comprise magnesium, for example a magnesium alloy such as, but not limited to, AZ31 magnesium alloy, AZ60 magnesium alloy, AZ70 magnesium alloy, AZ80 magnesium alloy, AZ91 magnesium alloy, a ZK magnesium alloy, or an aluminum alloy. In the case of being one-piece, the wheel disc 44 may comprise magnesium, for example a magnesium alloy; and in the case of being separate pieces, the wheel disc 44 may comprise aluminum, for example an aluminum alloy.
The wheel rim 42 may have a first and second flange 46, 48 located at respective free ends of the wheel rim. The first and second flanges 46, 48 may complement the shape of the respective bead portions, and may be constructed and arranged to seat the respective bead portions. The first and second flanges 46, 48 may extend circumferentially continuously around the wheel rim 42. Referring to
In some cases repeated vibrations, rolling, sliding, and other movement may cause abrasion, damage, and wear to the first and second flanges 46, 48 from the first and second bead portions 26, 28 at an interface 58 between the respective flanges and bead portions. The abrasion, damage, and wear may cause the tire 14 to lose inflation pressure over time. The wear resistant coating 10 may help prevent this abrasion, damage, and wear by, among other things, hardening the surfaces of the first and second flanges 46, 48, and in some cases by reducing friction between the first and second flanges and the first and second bead portions 26, 28.
Referring to
The wear resistant coating 10 may include a material that may harden the first and second flanges 46, 48 when applied thereto as compared to the first and second flanges without the wear resistant coating. In select embodiments, the wear resistant coating 10 may include titanium nitride, a ceramic, an oxide, a carbide, or a nitride. Other materials may be possible.
The exact application process of the wear resistant coating 10 may depend on, among other things, the material of the wear resistant coating, the structure of the wheel rim 42, and the material of the wheel rim. In select embodiments, the wear resistant coating 10 may be applied to the respective bead seat and on the respective opposing surface of the first and second flanges 46, 48 by a physical vapor deposition process, a chemical vapor deposition process, a plating process, a painting process, a direct current sputter process, a radio frequency sputter process, a laser ablation process, and a cathodic arc deposition process. Other application processes may be possible.
Depending on the material composition and application process of the wear resistant coating 10, in select embodiments the wear resistant coating may have a thickness in a range of about 1-5 microns or about 2-3 microns.
In use, the respective outer or opposing surfaces of the first and second bead portions 26, 28 may make direct contact with the wear resistant coating 10. The direct contact may help prevent abrasion, damage, and wear which may otherwise occur over time to the wheel rim 42 at the first and second flanges 46, 48. The wear resistant coating 10 may thus help keep the inflation pressure and prolong the useful life of the tire and wheel assembly 12.
One embodiment was evaluated by using what is known as a reciprocating wear test. In the evaluation, a first sample piece was placed in a tribotester, and a second and third sample piece were placed in the tribotester opposite the first sample piece. The first sample piece represented a bead portion of a tire; in this case the first sample piece was a 2 mm×2 mm bead portion of a Michelin® XW4® tire. The second sample piece represented a flange of a wheel rim including AZ31 magnesium alloy without a wear resistant coating. The third sample piece represented a flange of a wheel rim including AZ31 magnesium alloy with a wear resistant coating including titanium nitride. The wear resistant coating in the third sample piece was applied to the surface of the piece via a physical vapor deposition process, had a thickness of about 2 microns, and exhibited a hardness of about 23 GPa.
In the evaluation, the first sample piece was moved back-and-forth against the second sample piece and separately against the third sample piece. The first sample piece was moved back-and-forth with a load of about 10N in 6 mm strokes for about 1 million cycles for each of the second and third sample pieces. According to one estimate, these parameters simulate 500 miles of actual driving conditions.
An interferometer was then used to examine the wear tracks produced on the second and third sample pieces. In the second sample piece, the average wear amount (measured from the average unworn surface height) was about 1 micron. In the third sample piece, the average wear amount (measured from the average unworn surface height) was about 34 nanometers. Not all evaluations may produce the above results, and not all wear resistant coatings may produce the above results. Different evaluations including different tire samples, loads, cycles, stroke lengths, and the like may produce different results; and different material compositions, thicknesses, hardnesses, and the like may produce different results.
The above description of embodiments of the invention is merely exemplary in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.
