Truck tire with angled rib and variable width grooves in the thickness direction

Abstract

A heavy truck tire tread is provided that has first (32) and second grooves that are not completely oriented in the longitudinal direction so as to extend in both the longitudinal direction and the lateral direction. Both the first (32) and second grooves are spaced from and free from engagement with both the left side edge and the right side edge of the tread. The first groove (32) has a first segment (34) that has a first segment width (34) that is the same in length along the majority height (86) until a teardrop (42). A second segment (36) is adjacent the first segment (32) and has a second segment width (38) that is the same in length along a majority height of the first groove (32). The second segment width (38) is greater than the first segment width (34) along the majority height (86).

Description

TRUCK TIRE WITH ANGLED RIB AND VARIABLE WIDTH GROOVES IN THETHICKNESS DIRECTIONSTATEMENT 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 subject matter of the present invention relates to a truck tire that has a tread design that seeks to improve traction, wear, aggression resistance, and rolling resistance. More particularly, the present application involves a tread design that features an angled rib and grooves that have alternating widths as they extend in the thickness direction and at certain intervals along their length.BACKGROUND OF THE INVENTION

[0003] Manufacturers of heavy commercial vehicle tires have made huge progress in developing tire architectures and tire materials that allow them to increase the wear resistance of tire treads and reduce the rolling resistance of tires while at the same time improving their level of grip and resistance to road hazard. However, designing a tire to perform well in one category may cause it to perform worse in another category. For example, designing a tire with low rolling resistance for improved fuel efficiency may have the trade-off of having reduced traction and reduced wear life. In contrast, a tire that is designed for higher traction may also have an extended wear life, but will usually have higher rolling resistance and be less fuel efficient and may also suffer from aggression concerns. A tire that is designed for extended wear life generally has two different types of trade-off configurations. It may have good traction performance, but will have poorer rolling resistance performance. Alternatively, a tire designed for extended wear may have average rolling resistance performance, but may have worse traction performance.

[0004] It is known to provide tread designs that feature ribs at an angle to the longitudinal direction so that they do not extend completely 360 degrees around the tire. The ribs can extend from the shoulders toward the center and may terminate at the center or may terminate at another rib in the tread design. An example of a tire tread that utilized angled grooves and ribs may be seen with reference to Patent Cooperation Treaty publication number WO 2020 / 102056, the entire contents of which are incorporated by reference herein in their entirety for all purposes. The use of high angled ribs and grooves provide improved traction, wear resistance, and aggression resistance. However as discussed, improving some performance features of the tire may cause other performance features to be impacted and perform worse. Creating a tread design that increases all of the aforementioned performances would be desirable. 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. l is a perspective view of a heavy truck tire of the prior art.

[0007] Fig. 2 is top view of tread in accordance with one exemplary embodiment.

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

[0009] Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 2.

[0010] Fig. 5 is a top view of tread in accordance with another exemplary embodiment.

[0011] Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5.

[0012] Fig. 7 is a cross-sectional view taken along line 7-7 of Fig. 5.

[0013] Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 5.

[0014] Fig. 9 is a perspective view of tread in accordance with yet another exemplary embodiment.

[0015] Fig. 10 is a cross-sectional view taken along line 10-10 of Fig. 9.

[0016] Fig. 11 is a cross-sectional view taken along line 11-11 of Fig. 9.

[0017] Fig. 12 is a top view of tread in accordance with another exemplary embodiment.

[0018] Fig. 13 is a cross-sectional view taken along line 13-13 of Fig. 12.

[0019] Fig. 14 is a cross-sectional view taken along line 14-14 of Fig. 12.

[0020] The use of identical or similar reference numerals in different figures denotes identical or similar features.DETAILED DESCRIPTION OF THE INVENTION

[0021] 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.

[0022] The present invention provides for a tread 10 for a tire 68 that increases performance by way of a combination and configuration of various design elements. The tread 10 features a first groove 30 and a second groove 50 that have components of extension in the tread 10 in both the longitudinal and lateral directions 12, 14. Both of the grooves 30, 50 are spaced from and free from engagement with the edges 44, 70 of the tread 10. The first groove 30 is arranged in such a manner that it has a first segment 32 that extends along a portion of its length, and a second segment 36 adjacent the first segment 32 that likewise extends along a length of the first groove 30. The first segment 32 has a first segment width 34 that remains constant in size upon extension of the first segment 32 downward away from the upper surface 22 in the thickness direction 16, terminating at a teardrop 42 at the bottom of the first segment 32. The second segment 36 has a second segment width 38 that remains the same in length upon extension of the second segment 36 downward in the thickness direction 16 away from the upper surface 22. The second segment width 38 is greater than the first segment width 34 in the majority height 86 of the first groove 30. The design of the tread 10 overcomes the current compromises in that the angled grooves 30, 50 improves traction, wear and aggression resistance, and in that the segment 32, 36 width 34, 38 differences improve rolling resistance, traction, and wear.

[0023] Fig. 1 shows a prior art tire 68 that is a heavy duty truck tire 68. In this regard, the tire 68 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 68 may be a steer tire, a drive tire, a trailer tire, or an all position tire. The tire 68 includes a casing 66 onto whicha tread 10 is disposed. The tread 10 can be manufactured with the casing 66 and formed as a new tire 68, or the tread 10 can be a retread band that is attached to the casing 66 at some point after the casing 66 has already been used to form a retreaded tire 68. This is the case with all of the designs shown and described herein. They may all be tread designs of a brand new tire 68, or may be tread designs of a tread 10 for use in a retread tire 68. The central axis of the tire 68 extends through the center of the casing 66, and the lateral direction 14 of the tire 68 is parallel to the central axis. The radial direction 16, referred to also as the thickness direction 16, of the tire 68 is perpendicular to the central axis and the lateral direction 14, and the tread 10 is located farther from the central axis in the thickness direction 16 than the casing 66. The tread 10 extends all the way around the casing 66 in the circumferential direction 12, also referred to as the longitudinal direction 18, of the tire 68 and circles the central axis 360 degrees. The tread 10 includes a series of grooves and ribs that form a tread pattern. A rolling tread width 74 extends in the lateral direction 14 from the left side edge 70 of the tread 10 to an opposite right side edge 44 of the tread 10. The rolling tread width 74 represents that portion of the tread 10 that engages the ground through normal operation of the tire 68, and the shoulder edges 70, 44 may engage the ground as well as the area between these locations in the lateral direction 14. The center of the tread 10 is the location of the tread 10 at the lateral midpoint 82, halfway between the shoulder edges 70, 44 in the lateral direction 14.

[0024] The tread 10 is directional in that it is designed for forward rotation of the tire 68. The rolling direction 18 is the direction in the longitudinal direction 12 the tread 10 is designed to rotate. The tread groove 20 extends into the tread 10 from an upper surface 22 of the tread 10 and includes a bottom surface bounded on opposite sides by a leading edge wall 24 and a trailing edge wall 26. The leading edge wall 24 enters the contact patch of the tire 68 second as the tire 68 rotates in the rolling direction 18. The trailing edge wall 26 enters the contact patch of the tire 68 first before the leading edge wall 24. The bottom surface may extend from the leading edge wall 24 to the trailing edge wall 26 and can open into the tread edge 44 and can terminate on its opposite end into the rubber of the tread 10. The tread 10 going around the entire tire 68 can be directional so that it is designed to roll in one direction to achieve desired rolling performance in this one direction. The tread 10 may still rotate in the opposite direction from the desired rolling direction 18, but may not experience the designed for performance in this direction.

[0025] The tread grooves 20 can be variously shaped and have widths that can be greater than 2 millimeters. The shape of the center portion of the tread grooves 20 can be different than the shape of the shoulder portion of the tread grooves 20. A rib 72 is defined between the tread grooves 20 in the longitudinal direction 12. The rib 72 is not a circumferential rib 72 in that it does not extend all the way around the tread 10 in the longitudinal direction 12. Instead, the rib 72 extends from the tread edge 44 to the center of the tread 10. The rib 72 is angled relative to the longitudinal direction 12 so that the rib 72 extends so as to have a component of extension in both the longitudinal direction 12 and in the lateral direction 14. In contrast, a circumferential rib 72 would have a component of extension in the longitudinal direction 12 and no component of extension in the lateral direction 14.

[0026] The tread grooves 20 are likewise not circumferential grooves in that they extend so as to have a component of extension in both the longitudinal direction 12 and the lateral direction 14. The tread grooves 20 may open into and engage the shoulder edge 44, and terminate at some point at or near the center of the tread 10. Other tread grooves 20 could open at and engage and then extend from the tread edge 70 to the center of the tread 10. The tread grooves 20 may engage other grooves of the tread 10, and the ribs 72 between the tread grooves 20 may engage other ribs 72 of the tread 10 in other arrangements. The tread grooves 20 and ribs 72 have different components in the longitudinal and lateral directions 12, 14 along their lengths and as shown in Fig. 1, their angles change once. The shapes of the grooves 20 are all the same along their entire lengths such that the cross- sectional shape of the grooves 20 are the same along their entire lengths. There are no sipes present in the tread 10 and no sipes engage the tread edges 44, 70 or any of the grooves 20.

[0027] Fig. 2 is a top view of a tread 10 that can be part of a tire 68 or a retread band that is produced and subsequently attached to a casing 66 to form a retread tire 68 in accordance with one exemplary embodiment. The same tread pattern can repeat throughout the entire longitudinal length of the tread 10. The tread 10 has a first groove 30 and a second groove 50 that are in sequence next to one another in the longitudinal direction 12. The grooves 30, 50 can be variously shaped and have widths that are 2 millimeters or greater. A rib 72 is defined between the grooves 30, 50 in the longitudinal direction 12. The rib 72 is the portion of the tread 10 that is bound by the grooves 30, 50 in the lateral direction 14. The rib 72 is not a circumferential rib in that it does not extend all the way around the tread 10 in the longitudinal direction 18 when part of the tire 68. Instead, the rib 72 extends from the shoulder region of the tread 10 to the center of the tread 10 in the lateral direction 14when the grooves 30, 50 likewise extend to the center of the tread 10 in the lateral direction 14. The rib 72 is angled relative to the longitudinal direction 12 so that the rib 72 has a component of extension in both the longitudinal direction 12 and in the lateral direction 14. The rib 72 is not completely oriented in the longitudinal direction 12. In contrast, a circumferential rib would have a component of extension in the longitudinal direction 12 and no component of extension in the lateral direction 14 so as to be completely oriented in the longitudinal direction 12.

[0028] The first groove 30 and the second groove 50 likewise are not circumferential grooves in that they extend so as to have a component of extension in both the longitudinal direction 12 and the lateral direction 14. The grooves 30, 50 are spaced from the tread edges 70, 44 such that they do not engage either one of the tread edges 70, 44, and extend so as to terminate at some point at or near the center of the tread 10 in the lateral direction 14. The spacing of the grooves 30, 50 to the nearest tread edge 70 or 44 may be at least 5 millimeters, at least 7 millimeters, at least 10 millimeters, at least 12 millimeters, at least 15 millimeters, at least 17 millimeters, at least 20 millimeters, at least 25 millimeters, at least 30 millimeters, at least 35 millimeters, at least 40 millimeters, at least 60 millimeters, at least 70 millimeters, at least 80 millimeters, at least 90 millimeters, at least 100 millimeters, at least 125 millimeters, or at least 150 millimeters in accordance with various exemplary embodiments. Applicants have discovered that spacing the grooves 30, 50 from the tread edges 44, 77 increases the performance improvements previously mentioned.

[0029] The grooves 30, 50 may engage other grooves of the tread 10, and the rib 72 may engage other ribs of the tread 10 in other arrangements. The grooves 30, 50 and rib 72 have the same components in the longitudinal and lateral directions 12, 14 along their lengths. In this regard, the rib 72 and grooves 30, 50 can be described as being straight. In other embodiments, the grooves 30, 50 and rib 72 may curve or have two, three, four, or more angular changes along their lengths in relation to the longitudinal direction 12 and lateral direction 14. The tread 10 includes a plurality of grooves and ribs along its entire circumference in the longitudinal direction 12 and they may be configured the same as or differently from either one or both of the described grooves 30, 50 and tread 10. The grooves on the right hand side of the tread 10 can be configured in the same manner as those on the left hand side such that they are spaced from and not in engagement with either of the tread edges 44, 70.

[0030] The first groove 30 does not have the same cross-sectional shape along its entire length. Instead, the first groove 30 is broken up into at least two zones along its length and each of these zones does not have the exact same cross-sectional shape / size. The first groove 30 has a first segment 32 that extends along a quarter of its length. The entire first segment 32 has the same cross-sectional size and shape. A cross-sectional view of the first segment 32 is shown with reference to Fig. 4. The first segment 32 has a first segment width 34 that is the width of the first segment 32 and is measured in an orientation that is 90 degrees to the length of the first segment 32. The width of the first segment 32 is not measured in the lateral direction 14 because the first segment 32 is not a circumferential groove but is instead angled relative to the longitudinal direction 12. The first segment 32 increases continuously in length upon extension of the first segment 32 away from the upper surface 22 in the thickness direction 16. The first segment width 34 is thus largest at the base 46 of the first segment 32, and is smallest at the upper surface 22. Although shown in this embodiment as increasing continuously in the same amount, the first segment width 34 need not extend continuously along the entire height of the first segment 32, and need not extend at the same amount along the entire height of the first segment 32 in the thickness direction 16 in other embodiments. The base 46 is the portion of the first segment 32 that is farthest from the upper surface 22 in the thickness direction 16, and there is no teardrop located at the base 46 and instead the base 46 has a flat surface.

[0031] The second segment 36 of the first groove 30 is shown in cross-sectional view with reference to Fig. 3. The second segment 36 is configured differently than the first segment 32 and has the same cross-sectional size and shape along its entire length. The second segment 36 has a second segment width 38 that is measured at an orientation of 90 degrees to that of the length of the second segment 36. The direction of measurement of the second segment width 38 is not in the lateral direction 14 because the second segment 36 is not oriented completely in the longitudinal direction 12. The second segment width 38 decreases continuously, and at the same rate, from the upper surface 22 to the base 48 of the second segment 36. However, in other embodiments the rate of decrease may not be continuous, and in other embodiments the decrease may not be continuous such that the second segment width 38 increases or remains the same at one or more locations along the entire height of the second segment 36. The second segment width 38 is greatest at the upper surface 22 and is smallest at the base 48.

[0032] The first and second segments 32, 36 have the same lengths along the first groove 30, but they need not have the same lengths in other embodiments. The second segment 36 is located at the end of the first groove 30 and is the portion of the first groove 30 that is closest to the closest tread edge 70. The first segment 32 engages the second segment 36 and is immediately adjacent. The cross-sectional shapes of the first and second segments 36 are the same size and shape as one another, but are inverted. As the tread 10 wears, the same amount of open space in the first groove 30 will be realized since at any point in the thickness direction 16 the combined first and second segments 32, 36 present the same amount of open space. As the first groove 30 extends in the length direction, it features another segment immediately adjacent the first segment 32 that is configured in the exact same manner as the second segment 36, and then a fourth segment after this one that is configured the same way as the first segment 32. The segments alternate along the length of the first groove 30 such that the cross-sectional shape of the first groove 30 alternates three times along the entire length of the first groove 30. In this regard, four segments are present in the first groove 30 but any number two or larger can be present in other embodiments. Although two segment configurations are present, more than two can be present in other arrangements. The first groove 30 can feature segments that only have one of two different cross-sectional configurations. In other embodiments, from 3-10 different cross-sectional configurations are present in the first groove 30. The cross-sectional shape of the segments 32, 36 can be described as triangular in cross-sectional shape, although they are more trapezoidal in shape than triangular. However, for purposes of description and as used herein, a triangular shape description of the cross-section of the segments 32, 36 is broad enough to encompass cross-sectional shapes of the segments 32, 36 that are also trapezoidal.

[0033] The second groove 50 has four segments as well with two different configurations such that two of them are arranged the same as the first segment 32, and the other two are arranged the same as the second segment 36. One of the segments that is arranged the same as the second segment 36 is located closest to the closest tread edge 70. The second groove 50 is arranged in the same manner as the first groove 30. In fact, all of the grooves of the tread 12 in Fig. 2 are arranged in the same manner as one another having four segments along their lengths, each segment being one quarter of the length of the groove, and with the segments arranged like the second segment 36 are closest to the closest edge 44, 70 to the groove. In other embodiments, the grooves 30, 50 could be configured with segments32, 36 as those disclosed in United States Patent Nos. 11,124,025 and 11,034,191 which are owned by the present assignee and are incorporated herein by reference in their entireties for all purposes.

[0034] The first groove 30 is oriented at an angle 40 to the lateral direction 14 such that the first groove 30 has components of extension in both the longitudinal direction 12 and the lateral direction 14. The second groove 50 likewise is oriented at an angle 52 to the lateral direction 14 so that the second groove 50 has a component of extension in both the longitudinal direction 12 and the lateral direction 14. The angles 40 and 52 may be the same as one another or can be different from one another. The angles 40 and / or 52 may be from 40 degrees to 50 degrees, 45 degrees, from 50 degrees to 55 degrees, from 55 degrees to 65 degrees, from 65 degrees to 70 degrees, or from 70 degrees to 75 degrees. Still further, the angles 40 and / or 52 may be from 25 degrees to 50 degrees, from 40 degrees to 75 degrees, from 15 degrees to 80 degrees, or from 35 degrees to 70 degrees to the longitudinal direction 12 in other exemplary embodiments. The rib 72 may also be arranged at any of the aforementioned angles 40 and / or 52 with respect to the longitudinal direction 12. When the grooves 30 and 50 are straight, the angles 40 and 52 can be calculated as shown in Fig. 2 by measuring the angle between the longitudinal direction 12 and the center length of the grooves 30 and 50. When the grooves 30 and 50 have one or more changes of direction or are curved, the angles 40 and 52 can be calculated by drawing a line from the end of the groove 30 / 50 that is most outboard in the lateral direction 14 to the opposite end. The angle 40 / 52 can then be measured between this line and the longitudinal direction 12. As can be seen, angles 40, 52 that are 90 degrees represent grooves that are circumferential in orientation and thus run completely in the longitudinal direction 12 with no component in the lateral direction 14.

[0035] The tread 10 may be arranged so that none of the grooves engage the left or right tread edges 44, 70 and so that all of the grooves of the tread 10 are spaced some amount from the edges 44, 70 in the lateral direction 14. However, the tread 10 can have sipes 76, 78 that engage the tread edges 44 and 70. As shown, a first sipe 76 engages the tread edge 70 and extends to and engages the first groove 30, and in particular engages the first segment 32. A second sipe 78 is spaced from the first sipe 76 in the longitudinal direction 12 and likewise engages the left tread edge 70. The second sipe 78 extends from the left tread edge 70 to the second groove 50 and engages the second groove 50 at a first segment of the second groove 50. Additional sipes are present in the tread 10 and engage both thefirst and second grooves 30, 50 along with other grooves in the tread 10. These additional sipes likewise engage the right side edge 44. The sipes are arranged so that they all extend completely in the lateral direction 14 with no component of extension in the longitudinal direction 12. The sipes extend in such a manner that they are only made discontinuous by the presence of the various grooves 30, 50 within the tread 10.

[0036] The sipes in the tread 10 may have widths that are 2 millimeters or less. The sipes are shown as being straight in shape with a generally rectangular cross-sectional shape, but can be wavy, curved, angled or variously shaped with various cross-sectional configurations in other exemplary embodiments. The geometry in the thickness direction 16 of the sipes can also vary so that the sipes have different cross-sectional shapes at different ones of their depth locations in the thickness direction 16. The sipes could have different depths along their lengths or along the length of the rib 72 so as to be deeper or more shallow in the thickness direction 16 at various points. The rib 72 is shown as having a plurality of sipes therein. None of the sipes engage both the first groove 30 and the second groove 50 in the Fig. 2 embodiment. The successive sipes in the longitudinal direction 12 can have the same spacing from one another so that successive sipes are spaced the same amount from one another in the longitudinal direction 12. Other embodiments exist in which none of the sipes have spacing to a successive sipe that is the same as any other one. Further, although shown as being oriented completely in the lateral direction 14, the sipes may be oriented so as to have components of extension in both the lateral direction 14 and longitudinal direction 12 in other embodiments.

[0037] The sipes could be arranged so that one or more of the sipes engage both the first groove 30 and the second groove 50. There could be sipes that engage the first groove 30 and a groove on the right hand side of the tread 10. There may be sipes in the tread 10 that do not engage any of the grooves in the tread 10, although these sipes may engage the left tread edge 44 or the right tread edge 70. There is no circumferential groove in Fig. 2 or in other embodiments, but it is to be understood that other arrangements exist in which the tread 10 does have a circumferential groove which may be engaged by the first groove 30 and the second groove 50.

[0038] Another embodiment of the tread 10 is shown in Fig. 5 that again includes a first groove 30 and a second groove 50 that are angled relative to the longitudinal direction 12. The angles 40, 52 could be configured as previously discussed. The first groove 30 includes a first segment 32 and a second segment 36 in which the first segment 32 is closest to theclosest tread edge, which in this case is the left side tread edge 70. A first sipe 76 engages both the left side tread edge 70 and the first segment 32 of the first groove 30. The second segment 36 engages the first segment 32 and is closer than it to the lateral midpoint of the tread 10. A third segment extends from the second segment 36 and is closer to the lateral midpoint 82 of the tread 10 than the second segment 36. The third segment is configured the same way as the first segment 32. In this regard, the cross-sectional configuration of the first groove 30 alternates along the length of the first groove 30. There are thus two segments that are arranged the same as the first segment 32, but there is only one segment that is arranged with the same cross-sectional shape as the second segment 36. Each one of the three segments extends the same length along the first groove 30, and thus each one of the segments makes up one third of the length of the first groove 30. The entire first groove 30 is straight.

[0039] The cross-sectional shape of the first groove 32 is shown with reference to Fig. 6 that cuts through the first segment 32. The first segment width 34 is smallest at the upper surface 22. The first segment 32 extends halfway down in the thickness direction 16 such that the first segment width 34 is the same until this halfway point. The first segment width 34 at this point can be less than 2 millimeters or may be greater than 2 millimeters at the upper surface 22. At the midpoint in the thickness direction 16, the length of the first segment width 34 increases at a constant rate until the base 46 which is the bottom of the first segment 32 and thus the deepest point of the first segment 32 in the thickness direction 16. The first segment width 34 increases to its largest magnitude at the base 46. The first segment width 34 thus increases in the thickness direction 16 upon movement away from the upper surface 22, however this increase does not start at the upper surface 22 but instead begins at some point below the upper surface 22 in the thickness direction 16. Half of the height of the first segment 32 has the same first segment width 34, and the other half of the first segment 32 has a triangular cross-sectional shape. In other embodiments, the first segment width 34 can begin to increase at any point spaced from the upper surface 22 in the thickness direction 16 and need not begin this increase at the height midpoint from the upper surface 22.

[0040] The second segment 36 has a cross-sectional shape that is the same as the first segment 32 but is flipped. In this regard, the second segment 36 is shown in cross-section in Fig. 7. The second segment width 38 is longest at the upper surface 22 and decreases in a constant amount as the second segment 36 extends away from the upper surface 22. Atthe halfway point, the second segment width 38 stops decreasing in length and remains constant until the base 48. It is therefore the case that in various embodiments, the increase or decrease in the widths 34, 38 does not take place along the entire height of the segments 32, 36, or does not take place starting at the upper surface 22, or does not take place starting at the bases 46, 48. The second segment width 38 may begin to decrease in length at any point that is spaced from the upper surface 22 in the thickness direction 16 and this point need not be the midpoint.

[0041] The widths 34, 38 are sized so that the first and second segments 32, 36 present the same amount of void on the upper surface 22 of the tread 10 as the tread 10 wears down along its entire useful life. The presence of the third segment that is configured the same as the first segment 32 will cause the resulting first groove 30 to overall have a different degree of void presented on the upper surface 22 depending upon the wear depth of the tread 10. However, the counterpart groove on the right hand side of the tread 10 in the lateral direction 14 may be configured to have its third segment be arranged like the second segment 36 so that overall the two grooves present the same amount of void to the upper surface 22 at all points in the wear life of the tread 10.

[0042] The lateral midpoint 82 does not have a circumferential groove, and the various grooves of the tread 10 are spaced from and do not engage one another. None of the grooves engage the lateral midpoint 82. The grooves 30, 50 and all other grooves of the tread 10 are spaced from and do not engage either of the tread edges 44, 70 and this spacing may be as previously described with respect to the Fig. 2 embodiment. A sipe is shown as engaging the third segment of the first groove 50 and extending to and engaging the second segment of the second groove 50. As stated, the first sipe 76 engages the left hand tread edge 70 and extends to and engages the first segment 32 of the first groove 30 and does not engage the second groove 50. The first sipe 76 is wavy in shape in that it does not extend in a straight line but rather in a wavy shape generally in the lateral direction 14. The second sipe 78 likewise engages the left tread edge 70 and has a wavy shape generally in the lateral direction 14, but engages the first segment of the second groove 50 and is free from engagement with the first groove 30. It is therefore the case that the first and second sipes 76, 78 engage but a single one of the grooves 30 or 50 and terminate within these grooves 30, 50 and do not extend to nor engage any other grooves of the tread 10.

[0043] The first sipe 76 is shown in cross-section in Fig. 8. The first sipe 76 has a constant width from the upper surface 22 to a teardrop 80 of the first sipe 76 that is locatedat the bottom of the first sipe 76. The teardrop 80 has a circular cross-sectional shape. The width of the first sipe 76 increases at the teardrop 80 which has a width greater than the main portion of the first sipe 76. The shape of the first sipe 76 into the tread 10 is wavy and has an amplitude that decrease upon extension of the first sipe 76 in the thickness direction 16 away from the upper surface 22. In this regard, the first period of the wave of the first sipe 76 that is closest to the upper surface 22 has the greatest amplitude, and the wave of the first sipe 76 closest to the teardrop 80 has the smallest amplitude. The crosssection of the first sipe 76 can be the same along the entire length of the first sipe 76 from the left hand tread edge 70 to the first groove 30. The second sipe 78 may have a cross- sectional shape that is the same as the first sipe 78. In other arrangements, the first and second sipes 76, 78 may have a different cross-sectional shape than the one shown in Fig. 8, and there need not be a teardrop 80 at the bottom of the first and second sipes 76, 78.

[0044] Another embodiment of the tread 10 is shown with reference to Fig. 9 in which a portion of the tread 10 is shown in perspective view. The first and second grooves 30, 50 are angled relative to the longitudinal direction 12 and are arranged at different angles to the longitudinal direction 12. In this regard, the first groove 30 is straight, and the second groove 50 is curved and their angles 40, 52 are not the same as one another. The first groove 30 has a first segment 32 that is shown in cross-section in Fig. 10. The first segment width 34 is smallest at the upper surface 22 and increases in length upon extension away from the upper surface 22 in the thickness direction 16. A teardrop 42 is located at the base 46 and has a generally circular cross-sectional shape. The first segment width 34 thus increases in length until a point within the teardrop 42 at which time it decreases in length until reaching the end at the base 46.

[0045] The second segment 36 of the first groove 30 is shown in cross-section in Fig. 11, and the second segment width 38 decreases in length upon movement of the second segment 36 away from the upper surface 22 in the thickness direction 16. The cross- sectional shape of the second segment 36 at this point is concave in shape. The second segment 36 reaches a point at which the second segment width 38 is the smallest and this shape and size remains constant for some amount into the tread 10 in the thickness direction 16, at which point the second segment 36 opens up into the teardrop 42 which terminates at the base 42. The second segment width 38 thus remains constant at this smallest length for some amount in the thickness direction 16 at which point it becomes larger upon opening into the teardrop 42, eventually decreasing in size within the teardrop 42 andterminating at the base 48. The teardrop 42 is not completely circular in shape but is instead teardrop in shape, although it could be circular in other embodiments. The teardrop 42 can be present along the entire length of the first groove 30 and along the entire length of the second groove 50. Further, all of the grooves of the tread 10 may include the teardrop 42 at their bottoms.

[0046] The first and second segment 32, 36 shapes alternate along the length of the first groove 30. The second groove 50 has first and second segments 32, 36 configured in the same way as those of the first groove 30, and all of the other grooves in the tread 10 likewise have alternating segments that are configured in the same way as are the first and second segments 32, 36. A second sipe 78 engages the second segment of the first groove 30 and extends to and engages a second segment of the second groove 50. A first sipe 76 engages and extends between segments of the first groove 30 and another groove, and both of these segments are configured the same way as is the second segment 36. The groove that the first sipe 76 engages is the most adjacent groove to the first groove in the lateral direction 14 that is not intersected by another groove of the tread 10. The tread 10 design is set up so that all of the segments of all of the grooves that are arranged like the second groove 36 are engaged by sipes that connect two of these segments to one another. The segments of all of the grooves that are arranged like the first segment 32 are not engaged by any of the sipes of the tread 10.

[0047] The first segment width 34 has been described as increasing in length upon extension of the first segment 32 in the thickness direction 16 away from the upper surface 22. It is to be understood that this only needs to be the case for some portion of the first segment 32. Other portions of the first segment 32 may have the first segment width 34 decrease in length, or remain the same in length, upon extension of the first segment 32 in the thickness direction 16 away from the upper surface 22. Also, the second segment width 38 has been described as decreasing in length upon extension of the second segment 36 in the thickness direction 16 away from the upper surface 22. It is to be understood that this need only be the case for a portion of the second segment 36 and need not be the case for the entire second segment 36. In other portions of the second segment 36, the second segment width 38 may increase, or remain the same, in length upon extension of the second segment 36 in the thickness direction 16 away from the upper surface 22.

[0048] An additional embodiment of the tread 10 is illustrated with reference to Figs. 12- 14 in which a plurality of grooves such as the first and second grooves 30, 50 extend atangles 40, 52 to the lateral direction 14. The first groove 30 has a second segment 36 that has a second segment width 38 that is greatest at the upper surface 22 and extends at the same amount some distance into the tread 10 in the thickness direction 16. The second segment width 38 does not decrease at any point but instead remains the same along the entire height of the second segment 36 in the thickness direction 16. The first groove 30 is shown has having a majority height 86 and a minority height 88 in which the majority height 86 extends longer in the thickness direction 16 than does the extension of the minority height 88 in the thickness direction 16. Although the majority height 86 is shown as extending from the upper surface 22 and the minority height 88 is shown as extending from the base 46, 48 the positions of the majority and minority heights 86, 88 could be reversed in other arrangements. The majority and minority heights 86, 88 are continuous sections. In some embodiments, the bottom area of the second segment 36 in the thickness direction 16 proximate or at the base 48 could have a rounded or chamfered section such that the second segment width 38 does in fact decrease in size when deeper into the tread 10 in the thickness direction 16. However, the majority height 86 has a second segment width 38 that is continuous along the entire majority height 86 even in these embodiments. The bottom of the second segment 36 at the base 48 does not have a teardrop.

[0049] The first segment 32 can be seen in Fig. 13 and is completely within the perimeter defined by the second segment 36. The base 46 of the first segment 32 is at the same position as is the base 48 of the second segment 36 in the thickness direction 16 so that the two segments 32, 36 extend the same amount into the tread 10 in the thickness direction 16.

[0050] The first segment 32 is adjacent and engages the second segment 36 and has a first segment width 34 that is smallest at the upper surface 22. The first segment width 34 remains the same for the majority height 86 into the tread 10 in the thickness direction 16. The portions of the first and second segments 32, 36 that have the smaller widths 34, 36 are in alignment with one another as can be seen upon comparison of Figs. 13 and 14. The first and second segment widths 34, 38 are thus constant along the majority height 86, and along the entire majority height 86 the second segment width 38 is greater than the first segment width 34. The first segment 32 maintains a constant first segment width 34 along its entire height until its bottom at which point it terminates into a teardrop 42 at the bottom of the first segment 32. The base 46 is located at the bottom of the teardrop 42, and the first segment width 34 of the teardrop 42 is at some point greater than that at areas of thefirst segment 32 located above the teardrop 42 in the thickness direction 16. As such, the first segment width 34 increases at the teardrop 42, but this increasing amount is confined to the minority height 88 and there is no decreasing or increasing of the first segment width 34 in the majority height 86. The configurations of the first and second segments 32, 36 again alternate upon extension of the first groove 30 from one end to the other.

[0051] The tread 10 may include a rib 72 that is made of a rubber that has a hysteresis that has a max tan(6) that is from 0.01-0.18. In accordance with certain exemplary embodiments, the max tan(6) of the rib 72 may be from 0.01-0.11, from 0.01-0.05, from 0.05-0.09, from 0.09-0.11, from 0.07-0.11, from 0.08-0.11, from 0.06-0.09, from 0.005- 0.009, from 0.005-0.10, from 0.02-0.05, from 0.11-018, from 0.11-0.15, from 0.16-0.18, from 0.05-0.15, from 0.08-0.13, from 0.09-0.14, from 0.08-0.13, or from 0.04-0.12. Hysteresis can be measured by the tan(6) value of the rubber making up the rib 72. The loss factor “tan(6)” is a dynamic property of the rubber compound. It is measured on a viscosity analyzer (Metravib VA4000) according to Standard ASTM D5992-96 (2018). The response of a test specimen consisting of two cylindrical pellets each 2 mm thick and one centimeter in diameter is recorded (the test specimen is made from samples taken from a tire mid-way up the height of the zone concerned as close as possible to the region of the equatorial plane in a region that is thick enough to be able to form the test specimen), the specimen being subjected to simple alternating sinusoidal shear loadings at a frequency of 10 Hz, at a temperature of 60° C. The sweep covers amplitude of deformation from 0.1% to 25% peak to peak (on the outbound cycle) then from 25% to 1% peak to peak (on the return cycle). The results that are used here are the loss factor tan(6) and the complex dynamic shear modulus. The complex dynamic shear modulus is denoted “G*25” in reference to the 25% strain applied during the test. During the outbound cycle, the maximum value of tan6 that is observed is denoted “max tan(6)”.

[0052] The present tread 10 incorporates elements of high angled grooves 30, 50 with respect to the longitudinal direction 12 in addition to segments 32, 36 of the grooves 30, 50 that have different cross-sectional designs that alternate along the length of the grooves 30, 50. These features combined together along with in some instances the sipes 76, 78 and with the grooves 30, 50 being spaced from the edges 44, 70 allow for improved traction, rolling resistance, wear, and aggression resistance. Lower hysteretic rubber can be used in the rib 72 when these various design elements are used within the tread 10.

[0053] Although the design has been described with mostly reference to two grooves, the first groove 30 and the second groove 50, it is to be understood that this is simply for sake of convenience as multiple grooves greater than two in number can be arranged in the manners as described with respect to the two grooves 30, 50. As such, the tread 10 can include from 3-100 grooves and ribs that are organized the same way as the two grooves 30, 50 and the rib 72 have been described.

[0054] 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 first groove that is not completely oriented in the longitudinal direction so as to extend in both the longitudinal direction and the lateral direction, wherein the first groove is spaced from and free from engagement with both the left side edge and the right side edge, wherein the first groove has a majority height in the thickness direction that extends for a majority of the height of the first groove in the thickness direction, and wherein the first groove has a minority height in the thickness direction that extends for a minority of the height of the first groove in the thickness direction; a second groove that is not completely oriented in the longitudinal direction so as to extend in both the longitudinal direction and the lateral direction, wherein the second groove is spaced from and free from engagement with both the left side edge and the right side edge; a rib located between the first groove and the second groove, wherein the rib is not completely oriented in the longitudinal direction so as to extend in both the longitudinal direction and the lateral direction; and wherein the first groove has a first segment that has a first segment width that is the same in length along the majority height and remains the same in length until a teardrop at a bottom end of the first segment in the thickness direction, wherein the first groove has a second segment adjacent to the first segment, and wherein the second segment has a second segment width that is the same in length along the majority height, and wherein the second segment width is greater than the first segment width along the majority height.

2. The tread as set forth in claim 1, wherein the first groove is free from engagement with the second groove.

3. The tread as set forth in claims 1 or 2, wherein both the first groove and the second groove extend at a constant single angle to the rolling direction.

4. The tread as set forth in any one of claims 1-3, wherein a first sipe extends from the left side edge to the first groove and engages both the left side edge and the first groove, wherein a second sipe extends from the left side edge to the second groove and engages both the left side edge and the second groove.

5. The tread as set forth in claim 4, wherein the first sipe and the second sipe extend in a wavy pattern with varying amplitude into the tread in the thickness direction from the upper surface.

6. The tread as set forth in any one of claims 1-5, wherein a cross-sectional shape of the second segment is different than a cross-sectional shape of the first segment.

7. The tread as set forth in any one of claims 1-6, wherein the first segment width only increases or decreases in length at the teardrop, and wherein the second segment width is continuous at the majority height and the minority height and does not change at all in the second segment.

8. The tread as set forth in any one of claims 1-7, wherein the majority height extends from the upper surface and the minority height is not located at the upper surface.

9. The tread as set forth in any one of claims 1-8, wherein the rib has a max tan(6) that is from 0.01-0.18.

10. The tread as set forth in any one of claims 1-9, wherein the second segment has a rectangular cross-sectional shape, and wherein the first segment has a rectangular cross- sectional shape in the majority height.

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