Patent Application
20180056719
This invention pertains to heavy duty pneumatic tires such as are commonly used on earthmoving and mining equipment or heavy vehicles.
The present invention relates to tires intended to be fitted to a heavy vehicle, typically in the size ranges of 57 inch radial through 63 inch radial. Although not restricted to this type of application, the tire of the present invention may be used on off highway trucks including dump trucks, rigid frame trucks, large haulage trucks, equipment used for mining, and earthmoving equipment. These off-highway trucks travel across extremely challenging surfaces while typically carrying enormous loads. As a result, the tires on these vehicles are exposed to tremendous forces.
The tires of this sort are typically designed with a bead core in the lower sidewall of the tire that has a round, cross-sectional shape. These tires are usually mounted on wheels that have flat seated rims, so that the surfaces of the rim against which the base of the beads are mounted have a rim taper on the order of 5 degrees with respect to the axial direction. Because the tires are subjected to very high loads, it has become apparent that these tires are subject to wear in the bead region. This type of bead wear may be caused by uneven compression under the bead, resulting in uneven wear due to non-uniform shear stress. It is desired to have an improved tire design to reduce the wear in the bead region of the tire, and to reduce the shear stresses in the bead region of the tire.
“Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW);
“Axial” and “axially” mean lines or directions that are parallel to the axis of rotation 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;
“Belt reinforcing structure” means at least two layers of plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17 degrees to 27 degrees with respect to the equatorial plane of the tire;
“Bias Ply Tire” means that the reinforcing cords in the carcass ply extend diagonally across the tire from bead-to-bead at about a 25-50° angle with respect to the equatorial plane of the tire, the ply cords running at opposite angles in alternate layers;
“Carcass” means the tire structure apart from the belt structure, tread, under tread, and sidewall rubber over the plies, but including the beads;
“Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction;
“Chafers” refers to narrow strips of material placed around the outside of the bead to protect cord plies from the rim, distribute flexing above the rim, and to seal the tire;
“Chippers” means a reinforcement structure located in the bead portion of the tire;
“Cord” means one of the reinforcement strands of which the plies in the tire are comprised;
“Design rim” means a rim having a specified configuration and width. For the purposes of this specification, the design rim and design rim width are as specified by the industry standards in effect in the location in which the tire is made. For example, in the United States, the design rims are as specified by the Tire and Rim Association. In Europe, the rims are as specified in the European Tyre and Rim Technical Organization—Standards Manual and the term design rim means the same as the standard measurement rims. In Japan, the standard organization is The Japan Automobile Tire Manufacturer's Association.
“Equatorial plane (EP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread;
“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;
“Normal rim diameter” means the average diameter of the rim flange at the location where the bead portion of the tire seats;
“Normal inflation pressure” refers to the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire;
“Normal load” refers to the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire;
“Ply” means a continuous layer of rubber-coated parallel cords;
“Radial” means a direction that intersects the axis of rotation and is perpendicular thereto;
“Radial-ply tire” means belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from the bead to bead are laid at cord angles between 65 degrees and 90 degrees with respect to the equatorial plane of the tire;
“Section height” (SH) means the radial distance from the nominal rim diameter to the outer diameter of the tire at its equatorial plane; and,
“Section width” (SW) means the maximum linear distance parallel to the axis of the tire and between the exterior of its sidewalls when and after it has been inflated at normal pressure for 24 hours, but unloaded, excluding elevations of the sidewalls due to labeling, decoration or protective bands.
“Turn-up pad” means a strip of elastomer located between the chafer and the turnup end of the ply in the lower sidewall of the tire near the bead general area.
The invention may take physical form and certain parts and arrangements of parts, several preferred embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part whereof and wherein:
With reference to
The carcass further includes one or more steel cord reinforced plies 19 wrapped about each bead core 16 forming a turnup portion 20, more preferably an envelope turnup. The portion of the ply which extends from the crown towards the bead and is axially inwards of the bead is referred to as the down portion of the ply or down ply, while the portion of the ply which extends radially and axially outwards from the bead is referred to as the up ply or turnup portion. The one or more plies 19 are oriented in the radial direction. Disposed radially outwardly of the ply 19 in the crown area of the tire is a steel reinforced belt package 21 formed of two or more belts. A pair of sidewalls 18 extend radially inward from the radially outer tread 12 to the bead area. Located radially outward of the bead core 16 is an elastomeric apex 24. The apex as shown may have a triangular cross-sectional shape. Wrapped around the bead core 16 is an optional flipper (not shown). The flipper is preferably located between the bead core 16 and the carcass ply 19. Located on the axially inner edge of the bead area is a chafer 28.
As shown in
Because the bead core 16 is rotated an angle α, the radial height hr of the bead core as measured from the radially outermost point to the radially innermost point of the bead core cross-section, is in the range of 2 to 3 inches, and more preferably in the range of 2.3 to 2.7 inches. The axial width Wa is in the range of 3.5 to 4.5 inches, and more preferably in the range of 3.8 to 4.3 inches. The ratio of the bead height H to the width W is in the range of 0.4 to 0.8, and more preferably in the range of 0.4 to 0.7, and more preferably 0.5 to 0.6.
The bead core 16 is formed from a plurality of wound bead wires, each wire having a size in the range of 2-4 mm.
The bead core 200 has a first flat bead face 210 joined with a second flat bead face 220. The first flat bead face 210 is angled at an angle α1 in the range of 10-14 degrees, while the second flat bead face 220 is angled at an angle α2 in the range of 4-6 degrees. Thus, the bead face 210,220 has a dual taper not equal to the rim taper. The bead core 200 has rounded edges 230,240. Axially inner rounded edge 240 transitions to a radial edge 250. The bead core width is in the range of 1.5 to 2 times the bead height. The bead core 200 has an upper surface 260 that may be parallel to one of the bead faces 210,220. The upper surface 260 is preferably flat. The upper surface is joined by an axially-inward and axially-outward angled surfaces 262, 264. The upper surface 260 together with the angled surfaces 262, 264 are arranged to resemble the upper half of a hexagonal bead core. In other words, the angled surfaces 262, 264 make a γ angle 120 degrees with the upper surface 260.
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62381149 | Aug 2016 | US |
