PNEUMATIC TIRE FOR AN ELECTRIC VEHICLE

A pneumatic tire for an electric vehicle includes a pair of bead areas, a ground-contacting tread disposed radially outwardly of the pair of bead areas, and a pair of sidewalls. Each sidewall extends from a respective bead area to the tread. The tread joins each sidewall at a respective shoulder and the shoulders include an inboard shoulder and an outboard shoulder. A radius on the inboard shoulder is larger than a radius on the outboard shoulder. Physical features are formed on the tread, and each feature is formed in the shape of a fin. The features increase air flow towards an electric vehicle motor located inboardly of the tire. At least one of the fins includes a leading edge formed with micro-features.

FIELD OF THE INVENTION

The invention relates to pneumatic tires. More particularly, the invention relates to a structure of a pneumatic tire that includes features for an electric vehicle.

BACKGROUND OF THE INVENTION

In the manufacture of a pneumatic tire, the tire is typically built on the drum of a tire-building machine, which is known in the art as a tire building drum. Numerous tire components are wrapped about and/or applied to the drum in sequence, forming a cylindrical-shaped tire carcass. The tire carcass is then expanded into a toroidal shape for receipt of the remaining components of the tire, such as a belt package and a rubber tread. The completed toroidally-shaped unvulcanized tire carcass, which is known in the art at that stage as a green tire, is then inserted into a mold or press for forming of the tread pattern and curing or vulcanization.

As different types of vehicles are developed, the structural requirements of tires change. For example, for tires that are employed on electric vehicles, which are vehicles with electric drive systems, it is desirable to provide specific structural features on the tires which maximize the advantages of the electric drive systems.

As a result, it is desirable to provide a tire that includes features which increase the advantages of a drive system of an electric vehicle.

SUMMARY OF THE INVENTION

According to an aspect of an exemplary embodiment of the invention, a pneumatic tire for an electric vehicle includes a pair of bead areas, a ground-contacting tread disposed radially outwardly of the pair of bead areas, and a pair of sidewalls, in which each sidewall extends from a respective bead area to the tread. The tread joins each sidewall at a respective shoulder. The shoulders include an inboard shoulder and an outboard shoulder, in which a radius on the inboard shoulder is larger than a radius on the outboard shoulder.

According to another aspect of an exemplary embodiment of the invention, a pneumatic tire for an electric vehicle includes a pair of bead areas, a ground-contacting tread disposed radially outwardly of the pair of bead areas, and a pair of sidewalls, in which each sidewall extends from a respective bead area to the tread. Physical features are formed on the tread, and each feature is formed in the shape of a fin. The features increase air flow towards an electric vehicle motor disposed inboardly of the tire.

According to another aspect of an exemplary embodiment of the invention, a pneumatic tire for an electric vehicle includes a pair of bead areas, a ground-contacting tread disposed radially outwardly of the pair of bead areas, and a pair of sidewalls, in which each sidewall extends from a respective bead area to the tread. Physical features are formed on the tread, and each feature is formed in the shape of a fin. At least one of the fins includes a leading edge that is formed with micro-features.

Definitions

“Axial” and “axially” mean lines or directions that are parallel to the axis of rotation of the tire.

“Axially inward” and “axially inwardly” refer to an axial direction that is toward the equatorial plane of the tire.

“Axially outward” and “axially outwardly” refer to an axial direction that is away from the equatorial plane of the tire.

“Bead” means that part of the tire comprising an annular tensile member wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the design rim.

“Carcass” means the tire structure apart from the belt structure, tread, undertread, and sidewall rubber over the plies, but including the beads.

“Chafer” means a layer of reinforcing material around the bead in the rim flange area to prevent chafing of the tire by the rim.

“Chipper” means a band of fabric or steelcord located in the bead area with the function of reinforcing the bead area and stabilizing the lower sidewall of the tire.

“Cord” means one of the reinforcement strands of which the plies in the tire are comprised.

“Equatorial plane (EP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.

“Inboard” and “inboardly” refer to an axial direction that is toward the equatorial plane of the tire.

“Innerliner” means the layer or layers of elastomer or other material that form the inside surface of a tubeless tire and that contain the inflating fluid within the tire.

“Outboard” and “outboardly” refer to an axial direction that is away from the equatorial plane of the tire.

“Radial” and “radially” mean lines or directions that are perpendicular to the axis of rotation of the tire.

“Radially inward” and “radially inwardly” refer to a radial direction that is toward the central axis of rotation of the tire.

“Radially outward” and “radially outwardly” refer to a radial direction that is away from the central axis of rotation of the tire.

“Radial-ply tire” means a belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from bead to bead are laid at cord angles between about 65 to about 90 degrees with respect to the equatorial plane of the tire.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary embodiment of the tire of the present invention is shown inFIGS. 1 through 11and indicated at10.

Turning toFIGS. 1 through 3, the tire10preferably includes a pair of bead areas12, each one of which is formed with a bead core (not shown) that is embedded in the bead area. Each one of a pair of sidewalls14extends radially outwardly from a respective bead area12to a ground-contacting tread16. The tread12joins each sidewall14at a respective shoulder18, and is formed with multiple tread elements20. The tire10is reinforced by a carcass (not shown) that toroidally extends from one bead area12to the other bead area, as known to those skilled in the art. An innerliner (not shown) is formed on the inner or inside surface of the carcass. The tire10is mounted on a rim or wheel22, as known in the art, and defines a cavity30when mounted.

The tire10employs aspects or features that increase the efficiency of an electric vehicle. The aspects or features cool down an electric motor of the vehicle and reduce aerodynamic drag to increase battery range of the vehicle.

A first aspect or feature preferably includes a difference between the radius of each respective shoulder18. More particularly, as shown inFIG. 4, the sidewalls14include an inboard sidewall14aand an outboard sidewall14b. The inboard sidewall14ajoins the tread12at an inboard shoulder18a, and the outboard sidewall14bjoins the tread at an outboard shoulder18b. The inboard shoulder18ais formed with a first radius R1, and the outboard shoulder18bis formed with a second radius R2. The first radius R1, which is the radius on the inboard shoulder18a, is larger or rounder than the second radius R2, which is the radius on the outboard shoulder18b. The difference of the radius of each shoulder18, in which the radius R1of the inboard shoulder18ais larger than the radius R2of the outboard shoulder18bof the tire10drives cool air, which has been directed to the tire, towards an electric vehicle motor that is disposed inboardly of the rim or wheel22.

A second aspect or feature preferably includes physical features24formed on the tread20. Each physical feature24is formed in the shape of a fin, vane or blade. As shown inFIGS. 5 through 8, each physical feature24extends from an area of the tread20near the equatorial plane to the inboard shoulder18ato increase the air flow, represented by arrows indicated at A, driven towards the electric vehicle motor disposed inboardly of the rim or wheel22. Preferably, an angle of the each physical feature24relative to the axis of rotation of the tire10is between about zero (0) degrees and about ninety (90) degrees, and more preferably, corresponds to or matches an angle of fins or vanes26formed on a turbine28of the electric vehicle motor or on the wheel22to further increase cooling efficiency.

A third aspect or feature includes an outside or exterior shape of the tire10that reduces aerodynamic drag to enhance the battery range of the vehicle, as shown inFIGS. 3 and 4. Preferably, the radius R2of the outboard shoulder18bof the tire10is smaller than the radius R1of the inboard shoulder18a, which reduces aerodynamic drag of the tire, thereby increasing the battery range of the vehicle. In addition, an asymmetric cavity30, which is a cavity with an asymmetric cross section, preferably is formed when the tire10is mounted on the wheel22, thereby reducing aerodynamic drag of the tire.

A fourth aspect or feature includes an aerodynamic shape of the tire10with structural features that promote the extraction of heat through the rim or wheel22, as shown inFIGS. 9 and 10. More particularly, the combination of the radius R2of the outboard shoulder18bof the tire10being smaller than the radius R1of the inboard shoulder18aand the physical features24formed on the tread20enable increased air flow and promote the extraction of heat, indicated at arrow H, through the rim or wheel22.

A fifth aspect or feature includes micro-features34to reduce air noise, as shown inFIG. 11. Each physical feature24formed on the tread includes a leading edge32. The leading edge32of at least some of the physical features or fins24is covered with the micro-features34. Preferably, the micro-features34are formed as structural small or tiny hairs, which reduce air noise. More preferably, the leading edge32of each physical feature or fin24is covered with a texture of micro hairs34, which absorb impact noise from the air.

A base area36between each respective physical feature or fin24may also be formed with a plurality of micro-features38. The micro-features38formed in each base area36may be formed as structural small or tiny hairs, which reduce air noise. The micro-features38may be of different sizes, depending on particular design considerations for the tire10.

The effectiveness of the above-described features of the tire10has been confirmed through testing using aerodynamic simulations.

The present invention also includes a method of forming a tire10with features for an electric vehicle. The method includes steps in accordance with the description that is presented above and shown inFIG. 1 through 11.

It is to be understood that the structure of the above-described tire may be altered or rearranged, or components or steps known to those skilled in the art omitted or added, without affecting the overall concept or operation of the invention. For example, the teachings herein are applicable to a broad range of tires and may be useful in tire lines such as, but not limited to, passenger tires, radial medium truck tires, aircraft tires, and off-the-road tires, run-flat tires, and the like.

The invention has been described with reference to a preferred embodiment. Potential modifications and alterations will occur to others upon a reading and understanding of this description. It is to be understood that all such modifications and alterations are included in the scope of the invention as set forth in the appended claims, or the equivalents thereof.