Truck tire with shoulder edge voids

Abstract

A heavy truck tire tread is provided with a left shoulder groove spaced a distance X from the left side edge, and a left shoulder rib defined from the left side edge to the left shoulder groove. The left shoulder rib has a width that is the distance X in the lateral direction. A plurality of voids are in the left shoulder rib. All of the plurality of voids in the left shoulder rib are located a distance that is 0.5X or less to the left side edge in the lateral direction. The tread can include voids arranged like this only the left side rib and none in the right side rib, or alternatively only in the right side rib with none in the left side rib, or in both the left and right side ribs.

Description

TRUCK TIRE WITH SHOULDER EDGE VOIDSSTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with government support under the Vehicle Technology program Award Number DE-EE0009860 for DTNA awarded by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE). The Government has certain rights in the invention.FIELD OF THE INVENTION

[0002] The subj ect matter of the present invention relates to a truck tire that has a feature that provides a coupling force to the tread to improve irregular wear resistance. More particularly, the present application involves a tread design that features shoulder edge voids that are tuned to a specific location in the tread to both increase irregular wear resistance, and to increase resistance of the tread to aggression as opposed to other features that are used for irregular wear resistance in truck tires.BACKGROUND OF THE INVENTION

[0003] Tires in the trucking industry are provided with various features that act to improve performance characteristics such as rolling resistance, wet traction, endurance, and resistance to irregular wear. One solution for trucking steer tires is to provide a sacrificial rib at the shoulder of the tire to decrease the occurrence of irregular wear. The use of a sacrificial rib in these tires has been found to reduce incidences of irregular wear, but creates a location of potential tearing in the tire. Other designs which seek to reduce irregular wear in long haul trucking tires involve the inclusion of sipes in the shoulder ribs of the tread. Although capable of reducing irregular wear, the sipes or the sacrificial rib itself may be potential locations of tearing of the truck tire. This tearing is more prevalent when the shoulder ribs with sipes or the sacrificial ribs are used on truck tires that experience lower daily miles, more turns, and more stop / go usage than on truck tires that are in long haul applications with high milage in straight line usage. As such, providingtruck tires with a feature that reduces irregular wear without tearing and can be used in both long haul and regional or super-regional applications would be helpful.

[0004] It is known to put pin hole type voids into tires in order to impact the cure time of the tire during manufacturing. However, the placement of these pin hole type voids are across the entire width of a tread block or across the entire rolling tread width of the tire in order to speed up the cure time of the block or the entire tire. Further, the use of pin hole type voids is known to provide wet traction improvement and for anchor holes for studs for snow grip. These pin hole type voids are typically placed across the entire rolling tread width, typically in large lock locations, and away from the edges in order to achieve the desired benefits. Still further, the orientation of all of these pin hole type voids is completely in the thickness direction of the tread to be manufacturing friendly. The specific placement of pin hole type voids at specific inclination angles relative to the thickness direction, and at specific locations in the shoulder, for irregular wear and aggression resistance is not known. As such, there remains room for variation and improvement within the art.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art. is set forth in the specification, which makes reference to the appended figures, in which:

[0006] Fig. 1 is a perspective view of a heavy truck tire that has voids in the shoulders.

[0007] Fig. 2 is top view of tread that features shoulder edge voids in accordance with another exemplary embodiment.

[0008] Fig. 3 is a cross-sectional view- taken along line 3-3 of Fig. 2.

[0009] Fig. 4 is a top view' of tread that features shoulder edge voids in accordance with yet another exemplary embodiment.

[0010] Fig. 5 is a cross-sectional view of a void in the tread that is inclined relative to the thickness direction.

[0011] Fig. 6 is a cross-sectional view7of Fig 5 as the tire is rotated and the void approaches a contact patch of the tire.

[0012] The use of identical or similar reference numerals in different figures denotes identical or similar features.DETAILED DESCRIPTION OF THE INVENTION

[0013] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.

[0014] The present invention provides for a tread 12 for a heavy truck tire 10 that has a feature that produces a coupling force to improve irregular wear performance without sacrificing resistance to aggression. The tread 12 features voids 30 that are located in the shoulder rib 34 at locations close to the edge 22 of the shoulder rib 34. A plurality of the voids 30 can be located in the shoulder rib 34, 76, and they may be arranged within two or three rows 58. The shoulder groove 28. 74 is spaced a distance X 32 from the tread edge 22 in the lateral direction 16. The voids 30 are located close to the tread edge 22, 24 such that they are within a distance that is 0.5X or less to the tread edge 22, 24 in the lateral direction 16. In other embodiments, the voids 30 are a distance 38 that is 0.25X or less to the edge 22, 24 in the lateral direction 16. The voids 30 can be further tuned so that they are angled relative to the thickness direction 18 so that they are oriented at a void inclination angle 52 to the thickness direction 18. The placement of the voids 30 within the shoulder rib 34, 76 improve aggression resistance and reduce the occurrence of irregular wear as compared to other features that are added to the tread 12 to address irregular wear.

[0015] Fig. 1 show s a heavy truck tire 10. A heavy truck tire 10 is not designed for nor used with a car, motorcycle, or light truck (payload capacity less than 4.000 pounds), but is instead designed for and used with heavy duty trucks such as 18 wheelers, garbage trucks, or box trucks. The tire 10 may be a steer tire, a drive tire, a trailer tire, or an all position tire. The tire 10 includes a casing 60 onto which a tread 12 is disposed. The tread 12 can be manufactured with the casing 60 and formed as a new tire 10. or the tread 12 can be a retread band that is attached to the casing 60 at some point after the casing 60 has already been used to form a retreaded tire 10. This is the case with all of the designs show n and described herein. They may all be tread designs of a brand new tire 10. or may be treaddesigns of a tread 12 for use in a retread tire 10. The central axis of the tire 10 extends through the center of the casing 60, and the lateral direction 16 of the tire 10 is parallel to the central axis. The radial direction 18, referred to also as the thickness direction 18, of the tire 10 is perpendicular to the central axis and the lateral direction 16. and the tread 12 is located farther from the central axis in the thickness direction 18 than the casing 60. The tread 12 extends all the way around the casing 60 in the circumferential direction 14, also referred to as the longitudinal direction 14, of the tire 10 and circles the central axis 360 degrees. The tread 12 includes a series of grooves and ribs that form a tread pattern. A rolling tread width 26 extends in the lateral direction 16 from the left side edge 22 of the tread 12 to an opposite right side edge 24 of the tread 10. The rolling tread width 26 represents that portion of the tread 12 that engages the ground 62 through normal operation of the tire 10, and the shoulder edges 22, 24 may engage the ground 62 as well as the area between these locations in the lateral direction 16.

[0016] The tire tread 12 of Fig. 1 is organized into various grooves and ribs. The grooves are cuts in the upper surface 20 of the tread 12 that extend some amount from the upper surface 20 into the tread 12 in the thickness direction 18. The ribs are portions of the tread 12 that are located between the grooves, with the exception of the shoulder ribs 34. 76 that are bound by only one groove and the tread edges 22, 24. The left shoulder rib 34 is bound on one side in the lateral direction 16 by the left side edge 22 and on the other side by the left shoulder groove 28. The left shoulder rib 34 thus engages the left shoulder groove 28. The left shoulder groove 28 is a circumferential groove that extends 360 degrees around the central axis of the tire 10 in the longitudinal direction 14, and may be a straight groove or could be wavy or otherwise angled or curved in shape. The left shoulder groove 28 is shown as an angled groove in that it extends somewhat in the lateral direction 16 as it extends in the circumferential direction 14 so as to have an angled appearance as opposed to a wavy appearance.

[0017] An intermediate rib 64 engages both the left shoulder groove 28 and the intermediate groove 66 and is defined on either side by these two grooves 28, 66 in the lateral direction 16. A center rib 68 engages the pair of intermediate grooves 66 and 70 and is likewise bound on either side by these two grooves 66, 70 in the lateral direction 16. The center rib 68 is located in the lateral center of the tread 12 which is the center of the tread 12 in the lateral direction 16. A second intermediate rib 72 is defined between and engages the intermediate groove 70 and the right shoulder groove 74. Finally, the rightside of the tread 12 is provided with a right shoulder rib 76 which engages the right shoulder groove 74 on one side and is defined by the right shoulder groove 74 and the right side edge 24. The various grooves 28, 66, 70, 74 can be arranged and shaped in the same manner as one another, or they could be different from one another in different embodiments. The tread 12 in Fig. 1 has 5 ribs 34, 64, 68, 72, 76 and they may all share the same width in the lateral direction 16, or in some embodiments the shoulder ribs 34, 76 are longer in the lateral direction 16 than are any of the intermediate or center ribs 64, 68, 72. The tire 10 can be a directional tire 10 in that it is designed to rotate in a particular direction. In this regard, one or more architectural features of the tread 12 are arranged to perform best if the tire 10 rotates in one direction in the circumferential direction 14 as opposed to the opposite direction in the circumferential direction 14. The rolling direction 56 as shown in Fig. 1 is the preferred direction of rotation of the tire 10 to benefit from the design of these one or more features. In other embodiments, the tire 10 is not a directional tire and is designed for operation in either direction in the circumferential direction 14.

[0018] Another embodiment of the tire 10 is shown with reference to Fig. 2. The tread 12 is shown in top view and it is to be understood that this tread 12 can extend completely 360 degrees around the central axis. The tread 12 differs from that of the Fig. 1 embodiment in that the center rib 68 is divided up into two center ribs 68, 80 with a center groove 78 being between and engaging both of the center ribs 68, 80. The center rib 80 is located between and engages both the center groove 78 and the intermediate groove 70. The center groove 78 is an open groove with micro-sipes on either side. Micro-sipes are small cuts in the tread 12 which have a width that is less than or equal to 2 millimeters, and that extend for only a small distance from the groove and terminate blind into the tread 12. The intermediate grooves 66, 70 are closed grooves in that they are small openings at the upper surface 20, but may expand into larger openings deeper within the tread 12 from the upper surface 20 as the tread 12 wears down. Micro-sipes. that are angled so as to extend in both the longitudinal and lateral directions 14, 16, extend from the intermediate grooves 66, 70. The shoulder grooves 28, 74 are open grooves without any micro-sipes, and all of the grooves 28, 66, 78, 70, 74 are straight grooves in that they extend only in the longitudinal direction 14 around the tire 10 and are not wavy or otherwise angled in extension.

[0019] In order to increase coupling force to reduce irregular wear, the tread 12 is provided with a plurality of voids 30. These voids 30 can be circular in shape and can extend into the tread 12 from the upper surface 20 so as to be cylindrical in shape. The voids 30 arepositioned close to the left and right side edges 22, 24 to achieve these benefits. In order to establish the position of the voids 30, the relative position on the shoulder ribs 34, 76 relative to the left and right side edges 22, 24 is considered. The width of the left shoulder rib 34, which is its length in the lateral direction 16, is identified as the distance X and is designated with reference number 32. Distance X 32 is the length in the lateral direction 16 from the left side edge 22 to the left shoulder groove 28 in the lateral direction 16. It is to be understood that in other embodiments, the left shoulder groove 28 and / or the left side edge 22 are not completely straight, but can be wavy or angled so that the distance X 32 is not the same at every point in the longitudinal direction 14. In these instances, the longest distance X 32 that can be measured is what is then assigned as the distance X 32 for the purposes herein. Should the left shoulder groove 28 have micro-sipes, then these micro- sipes are ignored for purposes of establishing the distance X 32 at those points where the micro-sipes are present.

[0020] Once the distance X 32 is obtained for the left shoulder rib 34, the distance 36 is noted on the left shoulder rib 34. Distance 36 is one half of the distance X 32 and thus can be defined as the distance 36 that is 0.5X. This distance 36 is measured in the lateral direction 16 and extends from the left side edge 22 such that it may extend to different locations on the left shoulder rib 34 depending upon whether the left side edge 22 is completely straight or not. In the Fig. 2 embodiment, the voids 30 are located within distance 36 to the left side edge 22. In this regard, the voids 30 are located within a distance 0.5X to the left side edge 22. and thus the voids 30 are within one half of the distance X 32 to the left side edge 22 in the lateral direction 16. In some embodiments, there are no voids 30 from the distance 36 to the left shoulder groove 28, and in yet other embodiments this area from distance 36 to the left shoulder groove 28 is featureless or includes sipes or micro- sipes.

[0021] The voids 30 are organized into three rows 58 such that the voids 30 of the first row 58 are all located at the same position in the lateral direction 16, and all of the voids 30 of the second row 58 are all located at the same position in the lateral direction 16 that is different from the first row, and so that all of the voids 30 of the third row 58 are all located at the same position in the lateral direction 16 that is different than the first and second rows 58. The voids 30 of the first and third rows 58 share a common location in the longitudinal direction 14 such that one void 30 from the first row 58 and one void 30 from the third row 58 are side by side with one another and in the same position in the longitudinal direction14. The voids 30 of the second row 58 are offset from those of the first and third rows 58 in the longitudinal direction 14 such that none of the voids 30 of the first and second rows 58 share a common location with any of the voids 30 of the second row 58 in the longitudinal direction 14. All of the voids 30 in all of the rows 58 are spaced the same distance from one another in the longitudinal direction 14. The quantity of voids 30 in the tread 12 is high. In this regard, there is a large plurality of voids 30 that extend completely 360 degrees around the tire 10 in the longitudinal direction 14. In some embodiments, 1 void 30 can be present within every 6 millimeters, within every 8 millimeters, within every 10 millimeters, or within every 12 millimeters in the longitudinal direction 14 within a single shoulder rib 34, 76. In other embodiments, 2 voids 30 can be present within every 6 millimeters, within every' 8 millimeters, within every 10 millimeters, or within every 12 millimeters in the longitudinal direction 14 within a single shoulder rib 34, 76. In yet other embodiments, 3 voids 30 can be present within every 6 millimeters, within every 8 millimeters, within every710 millimeters, or within every 12 millimeters in the longitudinal direction 14 within a single shoulder rib 34, 76. In these arrangements, the 1, 2 or 3 voids 30 can all be within the same row 58 or within different rows 58.

[0022] The shoulder ribs 34, 76 can be solid ribs that extend completely 360 degrees about the tire 10 in the circumferential direction 14. Lateral grooves that extend from the left and right side edges 22, 24 into the shoulder ribs 34, 76 could be present in some embodiments and may or may not engage the shoulder grooves 28, 74. When these lateral grooves are present, the voids 30 are not located within the lateral grooves, but are instead still on the shoulder ribs 34, 76 at the outer surface 20. If the shoulder ribs 34, 76 are configured as tread blocks instead of a solid rib, then the voids 30 can again be provided as discussed such that they are not within the grooves formed between the tread blocks.

[0023] Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 2 and shows the voids 30 of the first row 58 and the third row 58 as being cylindrical in cross-sectional shape and side-by-side in the lateral direction 16. The upper surface 20 of the left shoulder rib 34 has no features save the voids 30. The voids 30 extend to a depth in the thickness direction 18 that is the same depth in the thickness direction 18 to which the left shoulder groove 28 extends in the thickness direction 18. In other embodiments, the voids 30 extend shorter in the thickness direction 18 from the upper surface 20 than does the length of extension in the thickness direction 18 that the left shoulder groove 28 extends in the thickness direction 18. In some embodiments, the voids 30 extend a longer distance in the thickness direction18 than does left shoulder groove 28. The voids 30 are blind voids that terminate within the tread 12 and are not connected to or in communication with any other feature of the tread 12. The bottom of the voids 30 are simply flat circular ends, but could be conical or otherwise rounded in other embodiments. The extension of the voids 30 from their ends to the upper surface 20 are provided such that they are featureless and form only a smooth inner wall along the inner tread 12 surface. The voids 30 when designed as having a circular cross-sectional shape can have a diameter along the majority of their length in the thickness direction 18 of 4 millimeters. 3 millimeters, 2 millimeters, 1 millimeter, from 0.25-1.5 millimeters, from 0.5-2.5 millimeters, from 0.75-3.5 millimeters, from 0.1-4 millimeters, from 0.1-3 millimeters, from 0.1-2 millimeters, or from 1 -3 millimeters in accordance with different embodiments.

[0024] The voids 30 in their assigned locations are targeted to change compliance near the left and right side edges 22, 24 and limit edge stress effect. The diameter of the voids 30, depth, quantity and inclination are designed to provide a coupling force that will improve irregular wear resistance at the shoulder region. The voids 30 are intended to provide added shoulder robustness against tearing of the shoulder sipes or sacrificial rib itself when these features are present. However, various embodiments exist in which the tread 12 does not have a sacrificial rib, and in which the shoulder ribs 34, 76 do not have sipes in them.

[0025] Another embodiment of the truck tire 10 tread 12 is shown with reference to Fig. 4. Here, the tread 12 again includes a pair of center ribs 68, 80 and four other ribs 34, 76, 64, 72 to result in a six rib tread 12 with five grooves 28, 66, 78, 70. 74. All of the grooves 28, 66, 78, 70, 74 are open grooves, and the intermediate grooves 66, 70 are the only ones that have micro-sipes, and these micro-sipes extend in both the lateral and longitudinal directions 14, 16. The left and right shoulder grooves 28, 74 are w axy in shape in that they don’t extend completely straight in the longitudinal direction 14 but instead have a sinusoidal like shape upon extension in the longitudinal direction 14 to have some component of extension in the lateral direction 16 as well. All of the ribs 34, 64, 68, 80, 72, 76 have either voids 30 in them or mi co-sipes in them. The voids 30 are again restricted to the edge areas of the tread 12 so that they are close to the left and right side edges 22, 24.

[0026] With reference to the left shoulder rib 34, the voids 30 are located closer to the left side edge 22 than to the left shoulder groove 28. The distance X 32 is established by finding the largest distance in the lateral direction 16 from the left side edge 22 to the left shouldergroove 28, considering this largest distance is measured completely in the lateral direction 16. The largest distance is that which engages the left shoulder groove 28 at the highest peak of its wave away from the left side edge 22 in the lateral direction 16. This location is shown in Fig. 4 and is designated as distance X 32. The distance 38 in this embodiment is 0.25X. As such, distance 38 is one fourth of the distance X 32 so that all of the voids 30 are located within the distance X 32 from the left side edge 22. In this regard, no portion of the voids 30 are located greater than the distance 38 from the left side edge 22. If the left side edge 22 is not completely straight so that it does in fact van’ in the lateral direction 16, then the distance 38 is measured from the most outboard portion of the left side edge 22. It is therefore the case that it may be possible for the position in the longitudinal direction 14 to be different between the place where distance X 32 is measured as compared to the place where distance 38 is measured.

[0027] The voids 30 are organized into two rows 58, and these rows are offset from one another in the longitudinal direction 14 such that the voids 30 of the first row 58 do not share the same location in the longitudinal direction 14 with the voids 30 of the second row 58. The voids 30 can be provided so that only 2 rows are present in the left shoulder rib 34 and no other features are present in the left shoulder rib 34. In other embodiments, only 3 rows 58 of voids 30 are present and no more than 3 rows of voids 30 are present. In yet other embodiments, 4, 5, 6 or 7 rows 58 of voids 30 are present such that there are no more than these individual number of rows 58. The voids 30 can be provided with respect to their depth in the same manner as previously discussed. Although the left shoulder groove 28 does not have micro-sipes, if they were present they would be ignored in the determination of the distance X 32. Still further, sipes that could be present in the left shoulder rib 34, that would not be classified as micro-sipes, would likewise be ignored in all of the embodiments in the calculation of the distance X 32.

[0028] Any of the voids 30 disclosed herein can extend either straight into the tread 12 in the thickness direction 18 from the upper surface 20, or can extend at an angle to the thickness direction 18 upon extension from the upper surface 20 into the tread 12. FIG. 5 shows a cross-sectional view of one of the voids 30 in which a negative inclination angle can be shown and described. This void 30 can be any or all of the voids 30 as discussed with respect to any of the embodiments. A void top point 46 is present at the top of the void 30 at the upper surface 20. The void 30 extends into the tread 12 until it terminates at a void bottom 40 which is the location farthest from the opening at the void top point 46.A void bottom point 44 is noted at a location at the void bottom 40. A void inclination line 48 extends from the void bottom point 44 to the void top point 46.

[0029] A reference line 50 extends through the void bottom point 44 and through the upper surface 20. The reference line 50 is oriented completely in the thickness / radial direction 18 and does not have a component in the longitudinal / circumferential direction 14 or the lateral / axial direction 16. The inclination of the lateral void 30 is observed upon comparison of the orientation of the void inclination line 48 to the reference line 50. The void inclination line 48 is oriented at a void inclination angle 52 to the reference line 50. The void inclination angle 52 may be from 5 degrees to 45 degrees, from 10 degrees to 45 degrees, from 11 degrees to 45 degrees, from 10 degrees to 20 degrees, from 11 degrees to 20 degrees, from 10 degrees to 15 degrees, from 13 degrees to 23 degrees, from 15 degrees to 28 degrees, from 15 degrees to 30 degrees, from 18 degrees to 28 degrees, from 20 degrees to 25 degrees, from 20 degrees to 45 degrees, from 10 degrees to 15 degrees, or from 12 degrees to 23 degrees in accordance with various exemplary embodiments. When describing all of the ranges of numbers in the present application, the ranges include both numbers at the top and bottom of the range along with the numbers within the ranges.

[0030] The inclination of the void inclination line 48 to the reference line 50 is negative in direction in that it is against the rolling direction 56 of the tread 12. In this regard, the void bottom point 44 is configured to enter the contact patch 54 of the tread 12 as it engages the ground 62 before the void top point 46. The reference line 50. the void bottom point 44, the void inclination line 48, the void top point 46, and the void inclination angle 52 all fall within a reference plane 42. The cross-sections in Figs. 5 and 6 fall within the reference plane 42 so all of these elements can be viewed in relation to one another. Fig. 4 shows the orientation of the reference plane 42 relative to the rest of the tread 12, and this reference plane 42 is designated in Fig. 4 with the numbers 42-42. As shown, the reference plane 42 is oriented in the longitudinal / circumferential direction 14 such that the longitudinal / circumferential direction 14, and the rolling direction 56, lie within the reference plane 42. The lateral / axial direction 16 is perpendicular to the reference plane 42.

[0031] FIG. 6 shows the tire 10 as being rotated and in engagement with the ground 37. The tire 10 is rolled in the rolling direction 56 so that a portion of the tread 12 has entered the contact patch 54 upon contact with the ground 62. The direction of inclination of the void 30 is shown in that the void bottom point 44 enters the contact patch 54 first beforethe void top point 46. In this regard, the void 30 is said to be oriented at a ‘'negative” void inclination angle 52 in that it is oriented away from the direction of travel of the tread 12 upon forward motion. If the truck were to be put into reverse, the opposite configuration would result in which the void top point 46 would first enter the contact patch 54 followed by the void bottom point 44. Upon forward motion of the tread 12, the void bottom point 44 will exit the contact patch 54 first before the void top point 46. The void inclination angle 52 causes the void 30 to be oriented relative to the longitudinal direction 14 so that the void 30 is at a non-zero void inclination angle 52, and the void 30 is not oriented in the lateral direction 16 so that the angle of inclination of the void 30 relative to the lateral direction 16 is zero degrees. The tire 10 and tread 12 may still rotate in the opposite direction from the desired rolling direction 56, but may not experience the designed for performance in this direction. The inclination of the voids 30 as discussed so that they are at a non-zero void inclination angle 52 helps provide a coupling force that improves irregular wear resistance of the tread 12 in the areas of the shoulder ribs 34, 76 or close to the side edges 22, 24. The void inclination angle 52, when provided as a non-zero degree angle, provides directionality to blocks of the tread 12 and imparts a localized coupling force at this area.

[0032] The distance 36 or 38 to which the voids 30 are positioned from the side edge 22 relative to the distance X 32 need not be 0.5X or 0.25X as described in the previous embodiments. This distance may be 0.4X, 0.3X, 0.2X, 0. IX, 0.45X, 0.35X, 0. 15X or 0.45X such that all of the voids 30 are located at or smaller than these distances to the side edge 22, 24. The distances mean that no portion of the voids 30 are greater than those distances from the side edge 22.

[0033] The present design has been described in relation to the voids 30 located in the left shoulder rib 34 and how they are positioned relative to the left side edge 22 and the left shoulder groove 28 using the distance X 32 and the distance 36, 38. It is to be understood that this is for sake of convenience and description of the voids 30 in the right shoulder rib 76 can be the same as those of the left shoulder rib 34 and a repeat of this information is not necessary. In this regard, the voids 30 in the right shoulder rib 76 can be arranged in rows 58 and / or may be angled relative to the longitudinal direction 14 at a void inclination angle 52, and may be sized and shaped as previously discussed. The distance X 32 in the right shoulder rib 76 can be the longest distance from the right side edge 24 to the right shoulder groove 74 with this measure being taken completely in the lateral direction 16 atthe same location in the longitudinal direction 14. The void 30 distance 0.5X 36, distance 0.25X 38 or any of the other aforementioned distances can be present so that the voids 30 in the right shoulder rib 76 are no greater than these distances to the right side edge 24. In some embodiments, the distance 0.5X 36, distance 0.25X, or other distance that bound the location of the voids 30 in the left shoulder rib 34 are the same as the distance 0.5X 36, distance 0.25X, or other distance that bound the location of the voids 30 in the right shoulder rib 76. The various tread 12 designs thus include voids 30 in both the left and right shoulder ribs 34, 76 that are positioned close to the left and right side edges 22, 24. Further, it is to be understood that in yet other embodiments, the voids 30 are provided as described in the right shoulder rib 76 with respect to positioning relative to the right side edge 24, and are not present within the left shoulder rib 34 with respect to positioning relative to the left side edge 22 as described. As such, embodiments exist in which the voids 30 are positioned as described within the left shoulder rib 34 and not as described within the right shoulder rib 76, are positioned as described within the right shoulder rib 76 and not as described within the left shoulder rib 34, and are positioned as described within both the right and left shoulder ribs 76, 34.

[0034] Although the truck tire 10 could be any type of heavy truck tire 10. in various embodiments, the truck tire 10 is a steer tire of a heavy truck. The tread 12 includes the voids 30 as described, but in various embodiments the tread 12 does not include a sacrificial rib. The voids 30 can be in a shoulder rib 34, 76 in which the shoulder rib 34, 76 is not a sacrificial rib. The void 30 design allows for the tread 12 to be provided so that a sacrificial rib can be eliminated in long haul applications of steer heavy truck tires 10 without negatively impacting the irregular wear performance of these steer tires 10. The void 30 designs have more resistance to aggression than would a tread 12 design with a sacrificial rib or with shoulder ribs 34, 76 that have lateral sipes therein. Also, the designs with voids 30 have more irregular wear resistance than tread 12 designs that have solid block shoulder designs.

[0035] The use of voids 30 in the left and right shoulder ribs 34, 76 proximate to the left and right side edges 22, 24 also provides the benefit of having a resulting tread 12 design that can be used for heavy truck tires 10 for both long haul and regional applications. Regional applications are those in which heavy truck tires 10 are used with less daily miles, more turns, and more stop / go usage than are long haul applications of heavy truck tires 10.The voids 30 as provided herein can improve both irregular wear and aggression resistance performance in heavy truck tire 10 treads 12.

[0036] While the present subject matter has been described in detail with respect to specific embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and / or additions to the present subject matter as would be apparent.

Claims

CLAIMSWhat is claimed is:

1. A heavy truck tire tread, comprising: a longitudinal direction, a lateral direction, and a thickness direction, wherein the tread has a rolling direction that is in the longitudinal direction; an upper surface; a left side edge; a right side edge, wherein a rolling tread width extends from the left side edge to the right side edge in the lateral direction; a left shoulder groove spaced a distance X from the left side edge in the lateral direction; a left shoulder rib defined from the left side edge to the left shoulder groove, wherein the left shoulder rib has a width that is the distance X in the lateral direction; and a plurality of voids in the left shoulder rib that extend from the upper surface into the left shoulder rib, wherein the plurality of voids are blind and are not connected to one another, wherein all of the plurality of voids in the left shoulder rib are located a distance that is 0.5X or less to the left side edge in the lateral direction.

2. The heavy truck tire tread as set forth in claim 1, wherein all of the plurality of voids in the left shoulder rib are located a distance that is 0.25X or less to the left side edge in the lateral direction.

3. The heavy truck tire tread as set forth in claim 1 or 2, wherein the upper surface at the left shoulder rib is featureless from the left shoulder groove to a distance that is 0.5X from the left shoulder groove in the lateral direction.

4. The heavy truck tire tread as set forth in any one of claims 1-3, wherein no grooves are located in the left shoulder rib, and wherein the left shoulder rib does not have blocks therein.

5. The heavy truck tire tread as set forth in any one of claims 1-4, wherein the plurality of voids are circular in shape with a diameter that is 2 millimeters or less, and wherein the plurality of voids extend from the upper surface at the left shoulder rib in thethickness direction to a depth that is the same depth or not as deep in the thickness direction as is a bottom of the left shoulder groove.

6. The heavy truck tire tread as set forth in any one of claims 1-5, wherein the left shoulder rib is not a sacrificial rib.

7. The heavy truck tire tread as set forth in any one of claims 1-6. wherein the plurality of voids has a first void that has a void bottom, wherein the longitudinal direction lies in a reference plane, wherein a void bottom point is located in the reference plane at the void bottom, wherein a void top point is located in the reference plane, wherein a void inclination line extends from the void bottom point to the void top point, wherein a reference line extends in the thickness direction through the void bottom point wherein the reference line does not have a component in the longitudinal direction or the lateral direction, wherein the void inclination line is at a void inclination angle to the reference line, wherein the void inclination angle is from and including 5 degrees to 45 degrees.

8. The heavy truck tire tread as set forth in claim 7, wherein the void inclination angle is from and including 10 degrees to 15 degrees.

9. The heavy truck tire tread as set forth in claim 7 or 8, wherein the void bottom point is configured to approach a contact patch before the void top point upon forward motion in the rolling direction.

10. The heavy truck tire tread as set forth in any one of claims 7-9, wherein the remaining ones of the plurality of voids are configured the same as the first void.1 1. The heavy truck tire tread as set forth in any one of claims 1-10, wherein the plurality of voids are cylindrical in shape.

12. The heavy truck tire tread as set forth in any one of claims 1-11, wherein the plurality of voids are arranged into rows that extend in the longitudinal direction, wherein the rows are separated from one another in the lateral direction.

13. The heavy truck tire tread as set forth in claim 12, wherein three rows of the plurality of voids are present such that there are no more than the three rows of the plurality of voids present.

14. The heavy truck tire tread as set forth in any one of claims 1-13, further comprising: a right shoulder groove spaced the distance X from the right side edge in the lateral direction; a right shoulder rib defined from the right side edge to the right shoulder groove, wherein the right shoulder rib has a width that is the distance X in the lateral direction; and wherein the plurality of voids are in the right shoulder rib that extend from the upper surface into the right shoulder rib, wherein the plurality of voids are blind and are not connected to one another, wherein all of the plurality of voids in the right shoulder rib are located a distance that is 0.5X or less to the right side edge in the lateral direction.

15. A heavy truck tire tread, comprising: a longitudinal direction, a lateral direction, and a thickness direction, wherein the tread has a rolling direction that is in the longitudinal direction; an upper surface: a left side edge; a right side edge, wherein a rolling tread width extends from the left side edge to the right side edge in the lateral direction; a right shoulder groove spaced a distance X from the right side edge in the lateral direction: a right shoulder rib defined from the right side edge to the right shoulder groove, wherein the right shoulder rib has a width that is the distance X in the lateral direction; and a plurality of voids in the right shoulder rib that extend from the upper surface into the right shoulder rib, wherein the plurality of voids are blind and are not connected to one another, wherein all of the plurality of voids in the right shoulder rib are located a distance that is 0.5X or less to the right side edge in the lateral direction.

16. The heavy truck tire tread as set forth in claim 15, wherein all of the plurality of voids in the right shoulder rib are located a distance that is 0.25X or less to the right side edge in the lateral direction.

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