MXPA98001235A - Truck rim, with low aspe relations - Google Patents

Abstract

The present invention relates to a pneumatic tire, radial layers, for a truck, with an aspect ratio below 0.70, which has a tread, a cover that includes two side walls, one or more radial layers, which extending from and wound around two annular flanges and a band reinforcing structure, positioned radially between the tread and the layers, this tread band has a plurality of circumferentially extending continuous grooves, which delimit a plurality Tread ribs, the radially outer surfaces of the plurality of tread ribs, define a surface of this radially outer tread, the outer edges axially of the tread surface are adjacent to the side walls, the distance in the middle between the edges of the tread define the center line of the tread This tread is characterized by: in a cross-section of the tread, the radially outer surface of this tread has a maximum diameter D at the center line of the tread and, on each side of the tread. center line, three radii of curvature R1, R2, and R3, in which the first radius of curvature R1, having its center C1 substantially in the equatorial plane, extends from a point P0 on the center line of the tread to a point P1 placed between 30 and 50% of half the width of the tread, which thus defines a first convex surface of the tread, externally radially, the second radius of curvature R2, which has its center C2 substantially in a line that passes through P1 and C1, it extends from point P1 to point P2, placed between 70 and 90% of half the width of the tread, which defines a second convex surface of the tread. tread, radially external, a third radius of curvature R3, having its center C3 external to the rim and substantially in a line passing through P2 and C2 and extending from point P2 to the edge of the tread defining therein a third Concave tread surface, external radialmen

Description

TRUCK RIM, WITH LOW ASPECT RATIO BACKGROUND OF THE INVENTION This invention relates to a radial pneumatic truck tire rim. More particularly, it teaches an improved tread profile for a tire with low aspect ratio, commonly referred to in the tire art as a Super Single tire. Historically in the mid-60s, The Goodyear Tire & Rubber Company introduced a wheel-oriented construction, in which one such tire can replace two conventional truck tires on two-axle semi-trailers. During 1965, Super Simple Oriented wheels were produced in Wolverhampton, England. The wear regime and the overall durability of these tires was poor and, therefore, the cost benefits of a single tire versus two conventional tires in a dual-unit are not fully realized. In the mid-70s, Michelin introduced the first Super Simple Radial All Steel rim. Goodyear in about 1976 also introduced such a radial tire, called the G165. In Europe, full three-axle trailers were introduced in Germany and three-axle semi-trailers in France. These changes reduced the propeller shaft loads typically from 13 to 11 metric tons. The gross vehicle weight load ("GVW") of three axles was limited to 22 metric tons. This greatly increased the use of Super Simple tires. In the mid-1980s, the Continental European GVW of tractors / semi-trailers and full trucks / trailers was increased from 38 to 40 metric tons. This change in the GVW made the two-axle semi-trailer vehicles into dual-tire equipment uncompetitive in view of the payload and thus forced trucking companies to exchange old two-axle units with those of three axles, thus increasing the demand for Super Simple tires. The GVW of three-axle trailers was increased to 24 metric tons and the tire load was increased from 4.125 kg to 4.500 kg. These increases in load limits have naturally required improved durability of the Super Simple type rim. The owners and operators of trucks observe their inventories of six Super Simple pneumatic tires and the corresponding metallic rims versus twelve conventional pneumatic tires and metallic rims for each three-axle trailer, as a significant cost advantage. The assembly of the Super Simple pneumatic rim assemblies and the corresponding metal rim is of less intense labor. The resulting weight savings when using Super Simple wheels means that you can carry more payload and these wide tires have a superior rolling resistance that provides fuel cost savings. All these benefits can be achieved if the tires can be designed with sufficient durability and wear of the tread. Truck tires are more than any other tire valued based on their load capacity and kilometers of useful life. The present invention has significantly improved the useful life of this type of rim, while also providing sufficient load capacity. In the past, the tread has been contoured with the use of a simple single or double radius of curvature, which originates the inner part of the rim. This configuration can provide a tread pattern that resembles a throttle on a wide rim of low aspect ratio, such as the Super Simple. The present invention corrects this inherently poor wear footprint configuration and provides a substantially rectangular footprint that does not have a butterfly appearance.

SUMMARY OF THE INVENTION A pneumatic tire 10 of radial layer truck is described, with an aspect ratio below 0.70. The rim 10 has a tread 20, a wrap 12, which includes two side walls 14, 16, one or more radial layers 18, which extend from and wrap around two annular flanges 13 and a reinforcing structure 15 band, placed radially between the tread and the layers 18. The tread 20 has a plurality of continuous grooves 22, extending circumferentially, which define or define a plurality of ribs 25 of the tread. The radially outer surfaces 26 of the plurality of ribs 25 of the tread define an external surface radially 30 of the tread. The axially external edges 21 of the tread 20 are adjacent to the sides 23 of this tread. The average distances between the edges 21 of the tread define the centerline C- ^ of the tread 20. In a cross-section of the tread 20, the radially outer surface 30 of the tread has a maximum diameter D at the center line C of this tread and, on each side of the center line, three radii of curvature R ^ R2, R3. The first radius of curvature R ^ has its central Cl substantially in the equatorial plane or the central line CL and extends from a point PO on the center line CL of the tread 20 to a point Pl, placed between the 30 and the 50% of half the width of the tread, which there defines a first surface 30A, convex, radially external, of the tread. The second radius of curvature 2, has its center C2 substantially in a line that passes through Pl and Cl and extends from the point Pl to a point P2, placed between 70 and 90% of the half of the width of the tread band that defines there a second radially convex, convex surface 30B of the tread. The third radius of curvature R3, has its center C3 external to the pneumatic rim and substantially in a line that passes through P2 and C2 and extends from point P2 to the edge of the tread, which defines there a third surface 30C concave, radially outer, of the tread. The second radius of curvature R2 is in the range of 1.3 to 2 times the first radius of curvature R and the third radius of curvature 3 is in the range of 0.7 to 2.5 times the first radius of curvature Rl7 preferably in the range of 1 to 2.5 times the first radius of curvature R] _. The third radius of curvature R3 is in the range of 0.7 to 1.5 times the second radius of curvature R2. The radius of curvature R ^ varies between 500 and 700 mm. The radius of curvature R3 varies between 450 and 1000 mm. , preferably between 700 and 1000 mm. Point Pl is located at approximately 40% of half the tread width and point P2 is located at approximately 80% of the half tread width. In the rim 10 of the preferred embodiment, there are at least four grooves 22, which extend circumferentially. The reinforcing structure 15 of the band comprises four bands 15A, 15B, 15C and 15D, the radial band 15A internally is a s band. The four bands have respectively inclinations with respect to the equatorial plane, starting with the radially inner band 15A, of approximately 552R, 212R, 212R and 21SL. The support rib adjacent the edge 21 of the tread is bevelled. The portion 24 of the side wall, adjacent to the supporting edge 21 is defined in a cross section by a fourth radius of curvature R4, which varies between 20 and 100 mm. , and has its center C4 external to the rim 10, the preferred rim has an R4 that is 50 mm.

Brief Description of the Drawings Figure 1 is a cross-sectional view of the rim 10 of the preferred embodiment, according to the invention. Figure IA is a profile of an enlarged portion of the cross-sectional view of Figure 1, showing in more detail the contour characteristics of the tread. Figure IB is a view of a reduced portion of the contour of the tread of Figure IB, showing the origins and intersections of the spokes of the preferred rim, according to the invention. Figure 2 is an exemplary illustration of a Super Simple tire tread of the radial type of the prior art, exhibiting a butterfly configuration. Figure 3 is an exemplary illustration of the tire tread 10 of the preferred embodiment of Figure 1.

Definitions "Apex" means an elastomeric filler located radially above the core and flange and between the layers and the layer bent upward. "Appearance Ratio" means the ratio of its section height to its section width.

"Tab" means that part of the rim comprising an annular tension element wound by the layer cords and configured, with or without other reinforcement elements, such as fins, splinters, apex, end caps and bevels, to adapt the metal rim of the design. "Band Structure" or "Reinforcement Bands" means at least two annular layers or parallel, woven or nonwoven cord cords, underlying the tread, not anchored to the flange and having left and right cord angles at the range of 172 to 27s with respect to the equatorial plane of the pneumatic tire. "Cover" means the frame, band structure, flanges, side walls and all other components of the rim, except the tread and the lower part of this tread. The cover can be new, of unvulcanized rubber or of rubber previously vulcanized to be adapted with a new tread. "Bevels" refers to narrow strips of material placed around the outside of the flange to protect the layers of the rim from the metal rim, distribute bending above this metal rim, and seal the pneumatic rim.

"Circumferential" means the lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. "Cord" means one of the reinforcing cables of which the layers in the pneumatic rim are comprised. "Lateral" means an axial direction. "Layer" or "Fold" means a continuous layer of parallel cords covered with rubber. "Radial" and "radially" mean radial directions towards or away from the axis of rotation of the pneumatic tire. "Pneumatic Tire of Radial Layers" means a pneumatic tire with bands or circumferentially restricted in which the laces of the layer, which extend from one flange to another, are arranged at cord angles between 652 and 902 with respect to the equatorial plane of the pneumatic tire. "Section Height" means the radial distance from the nominal diameter of the metal rim to the outside diameter of the pneumatic tire in its equatorial plane. "Section Width" means the maximum linear distance parallel to the axis of the pneumatic tire and between the outside of its side walls, when and after it has been inflated to a normal pressure for 24 hours, but without load, excluding the elevations of the lateral walls due to the labeling, decoration or protective band. "Support" means the upper portion of the side wall, just below the edge of the tread, support of the tread or support rib means that portion of the tread near the support. "Side wall" means that portion of a pneumatic tire, between the tread and the flange. "Tread" means that portion of the pneumatic tire that comes in contact with the road, under normal inflation and loading.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figure 1, a cross section of the radial pneumatic tire 10 is illustrated for use preferably in free-running axles of truck trailers. The rim 10 has a tread 20 and a cover 12. This cover 12 has two side walls 14, 16, one or more radial layers 18, which extend from and wrap around two annular flanges 13 and a structure 15 of web reinforcement positioned radially between the tread and the layers 18.

The layers 18 and web reinforcing structure 15 are reinforced elastomeric cord materials, the cords are preferably steel wire filaments and the elastomer is preferably a vulcanized rubber material. Similarly, the annular flanges 13 have steel wires wound in a bundle known as the flange core. The liner 19 is a component of preferably halobutyl rubber, which forms a chamber somewhat impermeable to air to contain the air pressure when the rim 10 is inflated. The cover 12 of the preferred embodiment of the invention, as illustrated in Figure 1, employs a flange 13 having a hexagonal core having an elastomeric apex 61 radially above the flange 13. The layer 18A turned upwards in the area of the flange is reinforced with a flap 67, chips 62, rubber and cloth bevels, 64, 65, rubber strips 66 and elastomeric wedges 63. As shown, the pneumatic tire band structure of the preferred embodiment has four bands reinforced with laces, 15A, 15B, 15C and 15D. The radially innermost layer or band 15A is divided into two axially spaced elements, one element in each half of the tread. This band layer 15A is commonly referred to as a split band. The cords are inclined at an angle of 55 for the slit band element 15A. The remaining bands 15B, 15C and 15D have bending inclinations with respect to the equatorial plane of 212R, 21L and 21L, respectively. Additionally, the web reinforcement structure 15 includes a rubber strip of rubber material 75 and a plurality of elastomeric after or wedges 72 at the side ends of the strips 15 in the vicinity of the side edge of the tread. Although not required for the practice of the concept of the invention, these characteristics are set forth as the characteristics employed in the preferred embodiment. The tread 20 has a plurality of contiguous circumferential grooves 22, a pair of beveled surfaces 24 located at the lateral ends of the tread and a plurality of tread ribs 25, including a pair of support ribs. 25A, each support rib 25A has a bevelled surface 24. The rim illustrated in Figure 1, according to the preferred embodiment, has at least four circumferentially extending grooves 22, most preferred rim 10 has five such grooves circumferential 22. More or fewer grooves may be used, depending on the width of the tread and other design considerations.

As shown in Figure 1, on the annular beveled surface 24, circumferentially continuous, is each adjacent side edge 21. The beveled surface 24, extending radially inside, of the support rib 25, does not contact the road under static load, as well as under normal load operating conditions, when the tire is new. Therefore, the contact width of the tread of the new rim is narrower than when the tread 20 of the rim is worn. The beveled surface 24 is believed to contribute to uniform wear of the tread. As the support ribs 25A are worn, the depth of the rib is reduced and this support rib 25A becomes stiffer. Additionally, the rib 25A becomes effectively wider and absorbs more load. This means that the rim 10 wears out and its tread wear rate actually decreases or slows due to this unique feature. This feature, when combined with a unique contour that actually increases the depth of the supporting rib 25A, makes it possible for the rim 10 to have surprisingly good wear performance. The average distance between the lateral edges 21 externally axially of the tread 20, as shown in Figure 1, defines the centerline CL O the equatorial plane of the tread 20. The lateral edge 21, axially external, is adjacent to the sides 23 of the tread of the support rib 25A and for the purposes of this invention, the side edges are the radially innermost edges of the beveled surface 24. The road contact surfaces 26, external radially , of the plurality of ribs 25 of the tread, define a tread surface 30, externally radially. The outer tread surface 30 is adjacent to and extends between the pair of beveled surfaces 24. As illustrated in Figures 1, IA and IB, the radially outer tread surface 30 has a maximum diameter D in the centerline CL of the tread and a constant internal radius of curvature Rlf extending laterally to the exterior from the equatorial plane or center line CL of the tread. The constant internal radius of curvature R ^ is preferably smaller than the maximum diameter D and originates at a location CL on the center line of the tread 20. The first radius of curvature Rl having its center Cl substantially in the equatorial plane , extends from a point P0 on the center line CL of the tread to a point Pl on each half of the tread placed between 30% and 50% of the half of the width of the tread that defines there a first convex surface 30A of tread, radially external. As further shown in Figures 1, IA and IB at the point P ^ located on each half of the tread 20, the curvature of the radially outer tread surface 30 changes, in that this surface 30 of The tread has a second radius of curvature R2, also originally internal to the pneumatic tire 10. As shown in Figure IB, the second radius of curvature R2, which has its center C2 substantially on a line passing through the tire. and Cl, extends from the point Pl to a point P2 placed between 80 and 90% of the half of the width of the tread, which defines there a second convex surface 30B of radially outer tread, as shown in FIG. shown in Figure IA. A third radius of curvature R3, has its center C3 external to the rim and substantially in a line passing through P2 and C2 and extends from the point P2 towards the edge of the tread adjacent the beveled surface 24, which defines there a third concave surface 30 of the tread, externally radially. The combination of the radially outer surfaces 30A, 30B and 30C, defines a contour, as shown in Figure IA, in which the surface 30 is represented as a line extending through the grooves 22 of the tread, as shown. The grooves 22 have a radial depth, which extends from the surface 30 to the base of the grooves 22. The contour of the outer surface 30 effectively changes the thickness of the tread to achieve a regular contact area or footprint. As shown in Figure IA, the line of dashes in silhouette from the point P2, which extends axially outward, has the curvature R, the actual contour of the tread has the outer curvature R3 and demonstrates the thickness of rubber of the tread that has been added to the ribs 25A of the support tread, which both improve the wear and improve the tread profile of the same. The rim 10 preferably has a relation between the first, second and third radii of curvature, so that the second radius of curvature R is in the range of 1.3 to 2 times the first radius of curvature R ^ and the third radius of curvature R3 is in the range of 0.7 to 2.5 times the first radius of curvature Rlf preferably of 1.0 to 2.5 times R ^. Preferably, the third radius of curvature R3 is in the range of 0.7 to 1.5 times the second radius of curvature R. The spokes are preferably oriented so that the adjacent portions of the contour of the tread are tangent. This relationship is achieved as shown in Figure IB. The rim 10, as illustrated in Figure 1, has the radius of curvature R ^ ranging from 500 to 700 mm. and the radius of curvature R3 that varies between 450 and 1000 mm. , preferably from 700 to 1000 mm. The rim, according to the preferred embodiment, has the point Pl placed at approximately 40 $ of half the width of the tread and the point P2 placed at approximately 80% of half the width of the tread . The rim, according to Figure 1, has the side portions 23 of the tread adjacent the beveled surface 24 of support and the side edge 21 defined in a cross section by a fourth radius of curvature R4, which varies between and 100 mm. , which has its center C4 external to the rim, the preferred rim 10 has R4 equal to 50 mm. The rim 10, when statically loaded, exhibits a tread as illustrated in Figure 3. The side edge 21 is shown in silhouette, because it is located in a non-contact portion of the beveled surface 24. The distance between the edge 21 and the contact edge is the axial width of the beveled surface 24.

As shown, the footprint is substantially rectangular with the guide and trailing edges being slightly convex. Figure 2 illustrates a Super Simple G199 tire tread from Goodyear. Referring to the footprint shown in Figure 2 of the Super Simple tire of the prior art, a butterfly configuration is shown, in which the guide and trailing edges of the concave shaped footprint. This means that the support ribs are traces that enter proportionally before the central portion of the tread. Also, as is readily apparent, the load is effectively supported unevenly with the support ribs carrying a disproportionate amount of the load. These support ribs, therefore, wear out more quickly and in a non-uniform manner, compared to the lighter load portion of the tread. Referring again to the tread of the rim of the present invention of Figure 3, the supporting ribs 25A and the central ribs 25 actually bring the load of the vehicle more proportionally and as a result a more uniform wear of the belt results. of bearing.

The test results show the comparable wear regimes of the experimental rim, according to the present invention, superior to those of a prior art rim of similar size and materials. In the test comparing the wear regimes of the three-axle trailers, the results indicated that tread wear varied by an improvement from 0 to 28%, depending on the position of the axle and other factors. In all cases, the appearance of the support rib 25A was greatly improved after the 80,000 kilometers of actual wear. The overall durability of the tires was also significantly improved with the projected mileage being up to 340,000 and more, depending on the position of the axle.

Claims (11)

1. CLAIMS 1. A pneumatic tire, radial layer, for a truck, with an aspect ratio below 0.70, which has a tread, a tire that includes two side walls, one or more radial layers, which extend from and they are wrapped around two annular flanges and a band reinforcement structure, positioned radially between the tread and the layers, this tread band has a plurality of circumferentially extending continuous grooves, which delimit a plurality of ribs of the tire. tread, radially outer surfaces of the plurality of tread ribs, define a surface of this external tread radially, the outer edges axially of the tread surface are adjacent to the walls Lateral, the distance to the middle between the edges of the tread define the center line of the tread, this band of rod is characterized by: in a cross section of the tread, the radially outer surface of this tread has a maximum diameter D in the center line of the tread and, on each side of the center line, three spokes of curvature Rl t R2 and R3, in which the first radius of curvature RL, having its center Cl substantially in the equatorial plane, extends from a point PO on the center line of the tread to a point Pl placed between the 30 and 50% of half the width of the tread, which thus defines a first convex surface of the tread, radially external; the second radius of curvature R, which has its center C2 substantially in a line passing through Pl and Cl, extends from point Pl to point P2, placed between 70 and 90% of half the width of the tread band, which defines there a second convex tread surface, externally radially; a third radius of curvature R3, having its center C3 external to the rim and substantially on a line passing through P2 and C2 and extending from point P2 to the edge of the tread defining therein a third concave surface of tread, externally radially.
2. 2. The pneumatic tire according to claim 1, wherein the second radius of curvature R2 is in the range of 1.3 to 2 times the first radius of curvature] _, and the third radius of curvature R3 is in the range of 0.7 to 2.5 times the first radius of curvature R] _.
3. 3. The pneumatic tire, according to claim 1, wherein the third radius of curvature R3 is in the range of 0.7 to 1.5 times the second radius of curvature R2.
4. 4. The pneumatic tire, according to claim 1, wherein the radius of curvature R ^ varies between 500 and 700 mm.
5. 5. The pneumatic tire, according to claim 1, wherein the radius of curvature R3 varies between 450 and 1000 mm.
6. The pneumatic tire, according to claim 1, wherein the Pl point is placed in approximately 40% of the half of the width of the tread, and the point P2 is located in approximately 80% of the half of the width of the tread.
7. 7. The pneumatic tire, according to claim 1, wherein there are five grooves extending circumferentially.
8. 8. The pneumatic tire, according to claim 1, wherein the reinforcing structure comprises four bands, the protective strip of the inner band radially being a split band.
9. 9. The pneumatic rim according to claim 8, wherein the reinforcing band structure comprises four bands, having respective inclinations with respect to the equatorial plane, starting with the internal radially slit band, of approximately 55QR, 212R, 212L and 212L.
10. 10. The pneumatic tire, according to claim 1, wherein the edge of the support is chamfered.
11. 11. The pneumatic tire according to claim 1, wherein the lateral portion of the tread, adjacent to the lateral edge, is defined in a cross section by a fourth radius of curvature R4, which varies between 20 and 100 m, that has its central C4 external to the rim.