Tire tread having variable amplitude sipe

Abstract

A tire includes a circumferential tread with a sipe formed therein. The sipe extends along a longitudinal axis between a proximal end and a distal end. The proximal end is at an outer surface of the circumferential tread. The sipe includes a mouth portion at the proximal end, a bulb portion at the distal end, and a wave portion that extends between and interconnects the mouth portion and the bulb portion. The wave portion includes at least one crest and at least one trough. An amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end.

Description

TIRE TREAD HAVING VARIABLE AMPLITUDE SIPEFIELD OF INVENTION

[0001] The present disclosure is directed to tire tread designs. More particularly the present disclosure it directed to a tire tread with a sipe having a variable amplitude wave portion.BACKGROUND

[0002] It is known to provide the tread surface of a tire with various features such as grooves, ribs, blocks, and lugs. Additionally, the tread surface may be provided with sipes to improve performance in low traction conditions. Known sipes, however, are provided as a substantially straight line extending radially inward into the tread and may negatively affect the directional stiffness of the tire or lead to irregular tire wear. Therefore, it is desired to provide a sipe that provides improved performance in low traction conditions while reducing or minimizing the aforementioned drawbacks.SUMMARY OF THE INVENTION

[0003] In one embodiment, a tire includes a circumferential tread with a sipe formed therein. The sipe extends along a longitudinal axis between a proximal end and a distal end. The proximal end is at an outer surface of the circumferential tread. The sipe includes a mouth portion at the proximal end, a bulb portion at the distal end, and a wave portion that extends between and interconnects the mouth portion and the bulb portion. The wave portion includes at least one crest and at least one trough. An amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end.

[0004] In another embodiment, a method of forming a sipe in a tire includes forming a blade that extends along a longitudinal axis between a proximal end and a distal end. The blade includes a mouth portion, a bulb portion, and a waveportion that extends between and interconnects the mouth portion and the bulb portion. The wave portion includes at least one crest and at least one trough. An amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end. The method further includes inserting the blade into a tread surface of the tire.

[0005] In yet another embodiment, a tire includes a circumferential tread with a sipe formed therein. The sipe extends along a longitudinal axis between a proximal end and a distal end. The proximal end is at an outer surface of the circumferential tread. The sipe includes a mouth portion at the proximal end and a bulb portion at the distal end. The bulb portion has a longitudinal axis that extends at a non-parallel angle with the longitudinal axis of the sipe. A wave portion extends between and interconnects the mouth portion and the bulb portion. The wave portion includes at least one crest and at least one trough.BRIEF DESCRIPTION OF DRAWINGS

[0006] In the accompanying drawings, structures are illustrated that, together with the detailed description provided below, describe exemplary embodiments of the claimed invention. Like elements are identified with the same reference numerals. It should be understood that elements shown as a single component may be replaced with multiple components, and elements shown as multiple components may be replaced with a single component. The drawings are not to scale and the proportion of certain elements may be exaggerated for the purpose of illustration.

[0007] Figure l is a peel-away perspective view of an exemplary tire,

[0008] Figure 2 is a cross-section of a portion of a circumferential tread of a tire, the circumferential tread having a sipe formed therein,

[0009] Figure 3 is a top view of a circumferential tread of a tire with a plurality of the sipes of Figures 2 formed therein,

[0010] Figure 4 is a side view of a blade for forming the sipe shown in Figures 2 and 3,

[0011] Figure 5 is a perspective view of the blade shown in Figure 4,

[0012] Figure 6 is a cross-section of a portion of a circumferential tread of a tire, the circumferential tread having an alternative embodiment of a sipe formed therein, and

[0013] Figure 7 is a flow chart of an exemplary method of forming a sipe in a tire.DETAILED DESCRIPTION

[0014] The following includes definitions of selected terms employed herein. The definitions include various examples and / or forms of components that fall within the scope of a term and that may be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of terms may be within the definitions.

[0015] “Axial” and “axially” refer to a direction that is parallel to the axis of rotation of a tire.

[0016] Circumferential” and “circumferentially” refer to a direction extending along the perimeter of the surface of the tread perpendicular to the axial direction.

[0017] “Radial” and “radially” refer to a direction perpendicular to the axis of rotation of a tire.

[0018] Sidewall” as used herein, refers to that portion of the tire between the tread and the bead.

[0019] Tread” as used herein, refers to that portion of the tire that comes into contact with the road or ground under normal inflation and normal load.

[0020] Tread width” refers to the width of the ground contact area of a tread which contacts with road surface during the rotation of the tire under normal inflation and load.

[0021] Directions are stated herein with reference to the axis of rotation of the tire. The terms “upward” and “upwardly” refer to a general direction towards the tread of the tire, whereas “downward” and “downwardly” refer to the general direction towards the axis of rotation of the tire. Thus, when relative directional terms such as “upper” and “lower” or “top” and “bottom” are used in connection with an element, the “upper” or “top” element is spaced closer to the tread than the“lower” or “bottom” element. Additionally, when relative directional terms such as “above” or “below” are used in connection with an element, an element that is “above” another element is closer to the tread than the other element.

[0022] The terms “inward” and “inwardly” refer to a general direction towards the equatorial plane of the tire, whereas “outward” and “outwardly” refer to a general direction away from the equatorial plane of the tire and towards the sidewall of the tire. Thus, when relative directional terms such as “inner” and “outer” are used in connection with an element, the “inner” element is spaced closer to the equatorial plane of the tire than the “outer” element.

[0023] While similar terms used in the following descriptions describe common tire components, it is understood that because the terms carry slightly different connotations, one of ordinary skill in the art will not consider any one of the following terms to be purely interchangeable with another term used to describe a common tire component.

[0024] Figure 1 is a peel-away perspective view of one embodiment of a tire 100. Tire 100 features a first annular bead 105 and a second annular bead 110. The annular beads, in part, secure the tire to a wheel. In an alternative embodiment, the tire comprises four or more beads.

[0025] The tire 100 further includes a body ply 115, which imparts shape to the tire, extending between first annular bead 105 and second annular bead 110. The body ply 115 extends around the first annular bead 105 and the second annular bead 110. In the illustrated embodiment, turn-up portions of the body ply 115 terminate in the bead regions of the tire. In alternative embodiments, turn-up portions of the body ply may terminate in the sidewall regions or crown regions of the tire. As one of ordinary skill in the art will understand, body ply 115 may contain reinforcing cords or fabric. In an alternative embodiment, multiple body plies are utilized.

[0026] A circumferential belt 120 is disposed radially upward of body ply 115 and extends axially across a portion of body ply 115. As one of ordinary skill in the art will understand, circumferential belt 120 may contain steel cords and reinforcing cords (both not shown). In an alternative embodiment, the circumferential belt lacks metal.

[0027] A reinforcement ply 125 is disposed radially upward of circumferential belt 120 and extends axially across a portion of body ply 115. As one of ordinary skill in the art will understand, additional reinforcement plies may be utilized. The reinforcement plies strengthen and stabilize the tire. In alternative embodiments, the tire contains three or more reinforcement plies. In another alternative embodiment, the reinforcement plies are omitted.

[0028] A cap ply 130 is disposed radially upward of circumferential belt 120 and second reinforcement ply 130. Cap ply 130 extends axially across a portion of body ply 115. In an alternative embodiment, a sealing gel layer is provided in the cap ply region. In an alternative embodiment, multiple cap plies may be employed. In another alternative embodiment, the cap ply may be omitted.

[0029] The tire 100 also includes an undertread 135 disposed radially upward of circumferential belt 120 and cap ply 130. The undertread 135 extends axially across a portion of body ply 115. An undertread is typically made up of rubber, and its thickness may vary depending on tire application. For instance, in retreading applications, a thicker undertread may be desired to accommodate buffing. In passenger tire applications, by comparison, a thinner undertread may be desired. In an alternative embodiment, the undertread may be omitted.

[0030] The tire 100 further comprises a first sidewall 140 and a second sidewall 145. First sidewall 140 extends between the first annular bead 105 and a first shoulder 150, which is proximately associated with an edge of circumferential tread 160. Second sidewall 145 extends between the second annular bead 110 and a second shoulder 155, which is proximately associated with the opposite edge of circumferential tread 160.

[0031] The tire 100 further includes a circumferential tread 160. In the illustrated embodiment, the circumferential tread 160 is separated by circumferential grooves 165, which divide circumferential tread 160 into five ribs. A plurality of sipes 170 are provided on the ribs. Additionally, the circumferential tread may include any combination of grooves, ribs, blocks, lugs, or other tread elements. In most applications, the circumferential tread is affixed to the tire whenthe tire is new. In an alternative embodiment, the circumferential tread is affixed as a retread.

[0032] The sipes 170 may improve performance of the tire 100 in wet, snowy, or other low traction conditions by increasing the number of biting edges on the tire 100. Additionally, the sipes 170 may facilitate deformation of ribs, blocks, and lugs and may also inhibit tire hysteresis loss.

[0033] While Figure 1 illustrates an exemplary pneumatic tire, it will be understood that the sipes described herein may be employed in the tread of a nonpneumatic tire.

[0034] An exemplary sipe 1000 is shown in Figures 2 and 3. The sipe 1000 is formed in a circumferential tread 505 of a tire 500. Description of the sipe 1000 will be made with reference to an x, y, z Cartesian coordinate system that is shown as a legend in each of the figures. As used herein, the x-axis may extend along a circumferential direction of a tire, the y-axis extend along in a direction transverse to the circumferential direction of the tire, and the z-axis extend along a radial direction of the tire. The use of this coordinate system is only to facilitate description of the sipe 1000 and is in no way limiting.

[0035] The sipe 1000 extends along a longitudinal axis 1005 between a proximal end 1010 and a distal end 1015. The longitudinal axis 1005 extends substantially radially, parallel with the z-axis. The proximal end 1010 is located at an outer surface of the circumferential tread 505, and the distal end 1015 is located radially inward of the proximal end 1010. The circumferential tread 505 includes a first wall 1020 and a second wall 1025 that define the sipe 1000. The first wall 1020 is spaced from the second wall 1025. The sipe 1000 has a thickness t that is defined as a distance between the first wall 1020 and the second wall 1025 along the x-axis (i.e., along a direction extending perpendicular to the walls). The sipe 1000 includes a mouth portion 1030 at the proximal end 1010, a bulb portion 1035 at the distal end 1015, and a wave portion 1040 that extends between and interconnects the mouth portion 1030 and the bulb portion 1035. The longitudinal axis 1005 is centered in the mouth portion 1030 along the x-axis.

[0036] The sipe 1000 opens to the outer surface of the circumferential tread 505 at the mouth portion 1030. The thickness t of the sipe 1000 at the mouth portion 1030 gradually decreases in a direction moving from the proximal end 1010 toward the distal end 1015. In other words, the thickness of the sipe 1000 at the mouth portion 1030 tapers so that the first and second walls 1020, 1025 at this portion are angled toward one another when viewed in a direction moving from the proximal end 1010 toward the distal end 1015. Providing the mouth portion 1030 with this tapered configuration improves performance of the tire in wet conditions and ensures a smooth transition to the wave portion 1040. Additionally, the tapered configuration improves the manufacturing process by making it easier to remove the sipe forming blade from the tire and improves the robustness of the sipe forming blade by allowing part of the blade to be thicker.

[0037] According to one example embodiment, the maximum thickness t of the sipe 1000 at the mouth portion 1030 (i.e., the thickness t of the sipe 1000 where the sipe 1000 opens to the outer surface of the circumferential tread 505) is 6 mm and the minimum thickness t of the sipe 1000 at the mouth portion 1030 is 0.5 mm. In another example embodiment, the maximum thickness t of the sipe 1000 at the mouth portion 1030 is 1.2 mm and the minimum thickness t of the sipe 1000 at the mouth portion 1030 is 0.3 mm In alternative embodiments, the maximum thickness t of the sipe 1000 at the mouth portion 1030 is in the range of 0.2-10 mm and the minimum thickness t of the sipe 1000 at the mouth portion 1030 is in the range of 0.15-2 mm. In alternative embodiments, the mouth portion may have any desired thickness or range of thicknesses. In other alternative embodiments, the mouth portion may have any desired configuration. For example, the thickness of the sipe at the mouth portion may be constant so that the first and second walls are parallel with one another.

[0038] The thickness t of the sipe 1000 at the bulb portion 1035, in general, gradually increases in a direction moving toward the distal end 1015. In other words, the thickness of the sipe t at the bulb portion 1035 flares so that the first and second walls 1020, 1025 are angled away from one another when viewed in a direction moving toward the distal end 1015. The circumferential tread 505 furtherincludes a curved bottom surface 1045 that further defines the sipe 1000. The curved bottom surface 1045 is provided at the bulb portion 1035 and extends between and interconnects the first and second walls 1020, 1025 at the distal end 1015 of the sipe 1000. Providing the bulb portion 1035 with the curved bottom surface 1045 provides a more robust arrangement and allows the bottom of the sipe to resist crack propagation. Additionally, the flared configuration of the bulb portion 1035 improves the manufacturing process by making it easier to remove the sipe forming blade from the tire. According to one example embodiment, the maximum thickness t of the sipe 1000 at the bulb portion 1035 (i.e., the thickness t of the sipe 1000 where the first and second walls 1020, 1025 join the curved bottom surface 1045) is 1.2 mm, the minimum thickness t of the sipe 1000 at the bulb portion 1035 is 0.5 mm, and the curved bottom surface 1045 has a radius of curvature r of 0.8 mm. The maximum thickness t of the sipe 1000 at the bulb portion is 1.2 mm while the rest of the values remain the same as described above. In alternative embodiments, the maximum thickness t of the sipe 1000 at the bulb portion 1035 is in the range of 0.2-5 mm, the minimum thickness t of the sipe 1000 at the bulb portion 1035 is in the range of 0.15-2 mm, and the curved bottom surface 1045 has a radius of curvature r in the range of 0.1 to 2.5 mm. According to one embodiment, the radius of curvature r is half the maximum thickness of the bulb portion 1035. In alternative embodiments, the bulb portion may have any desired thickness. In other alternative embodiments, the bulb portion may have any desired configuration. For example, the bottom surface may be made up of different curved surfaces that each have a different radius of curvature. As another example, the bottom surface may be straight rather than curved. As yet another example, the thickness of the sipe at the bulb portion may be constant so that the first and second walls are parallel with one another.

[0039] The wave portion 1040 (sometimes referred to as an undulation) includes a plurality of crests 1050 and troughs 1055. As used herein, crests 1050 refer to parts of the wave portion 1040 that are located to the right of the longitudinal axis 1005 of the sipe 1000 (from the perspective shown in Figure 2), and troughs 1055 refer to parts of the wave portion 1040 that are located to the left of thelongitudinal axis 1005 of the sipe 1000 (again from the perspective shown in Figure 2). A period^ of the wave portion 1040 (i.e., distance between adjacent crests 1050 or adjacent troughs 1055) is constant along the entire wave portion 1040. An amplitude A of the wave portion 1040 (i.e., distance between the center of a crest 1050 or trough 1055 to the longitudinal axis 1005 of the sipe 1000) decreases in a direction moving from the proximal end 1010 toward the distal end 1015. In other words, the amplitude A of the wave portion 1040 decays in a direction moving from the proximal end 1010 toward the distal end 1015.

[0040] Providing the wave portion 1040 with a constant period and a decaying amplitude A improves tire performance and also improves the manufacturing process. Regarding tire performance, the wave portion can allow the first and second walls 1020, 1025 to interlock with one another, thereby advantageously providing improved directional stiffness and improved wear life. Additionally, when the tire is newer the tread is thicker, thereby increasing the need to bolster directional stiffness. As the tire wears, however, the tread becomes thinner and the need to bolster directional stiffness decreases. The wave portion 1040 takes this wear into consideration, providing a larger amplitude A toward the proximal end 1010 that creates stronger interlocking between the first and second walls 1020, 1025 when the tire is newer and the tread is thicker, thus providing generally greater levels of bolstered directional stiffness, and a smaller amplitude A toward the distal end 1015 that creates relatively weaker interlocking between the first and second walls 1020, 1025 when the tire is worn and the tread is thinner, thus providing generally lower levels of bolstered directional stiffness. Additionally, the decaying amplitude A makes it easier to remove the sipe forming blade from the tire, thereby improving the manufacturing process.

[0041] According to one example embodiment, the period of the wave portion 1040 is 4 mm , and the crests 1050 and troughs 1055 have a maximum amplitude A of 1.3 mm and a minimum amplitude A of 0.7 mm. Furthermore, according to this example embodiment, the amplitude A of each crest 1050 or trough 1055 decreases by 0.27 mm compared to an adjacent crest 1050 or trough 1055. According to another example embodiment, the period of the wave portion 1040is 4 mm , and the crests 1050 and troughs 1055 have a maximum amplitude A of 1.23 mm and a minimum amplitude A of 0.44 mm. In alternative embodiments, the period of the wave portion 1040 is in the range of 2.5-6.0 mm, the crests 1050 and troughs 1055 have a maximum amplitude A in the range of 0.5-4 mm, a minimum amplitude A in the range of 0-4 mm, and the amplitude A of each crest 1050 or trough 1055 decreases in the range of 0.1-0.27 mm compared to an adjacent crest 1050 or trough 1055. In other alternative embodiments the wave portion may have any desired decaying amplitude configuration. For example, the value for the decrease in amplitude of each crest or trough may be variable. According to one example embodiment, the crests and troughs may be configured so that the largest decrease in amplitude occurs toward the mouth portion and the smallest decrease in amplitude occurs toward the bulb portion.

[0042] In the illustrated embodiment, the crests 1050 and troughs 1055 alternate with one another in a direction moving from the proximal end 1010 toward the distal end 1015. There are three crests 1050 and three troughs 1055, with a trough 1055 adjacent to the mouth portion 1030 and a crest 1050 adjacent to the bulb portion 1035. In alternative embodiments, two or more troughs or two or more peaks may be provided in succession. In other alternative embodiments, there may be a greater or fewer number of peaks or troughs. In still yet other embodiments, a crest may be provided adjacent to the mouth portion or a trough may be provided adjacent to the bulb portion.

[0043] The thickness t of the sipe 1000 at the wave portion 1040 is constant. According to one embodiment, the thickness t of the sipe 1000 at the wave portion 1040 is 0.3 mm. According to another embodiment, the thickness t of the sipe 1000 at the wave portion 1040 is 0.5 mm. In alternative embodiments, the thickness t of the sipe 1000 at the wave portion 1040 is in the range of 0.15-2 mm. In other alternative embodiments, the wave portion may have any desired thickness.

[0044] As shown in Figure 3 , the sipe 1000 extends straight along the y-axis. In other words, the sipe is substantially straight along a direction that is orthogonal to the longitudinal axis 1005. Thus, when viewed from the perspective shown in Figure 3, the sipe 1000 appears as a substantially straight line. Furthermore, as willbe appreciated by one of ordinary skill in the art, the sipe 1000 will continue to appear as a substantially straight line as the tire 500 wears. In Figure 3, each sipe 1000 extends substantially transverse relative to a circumferential direction of the tire. In alternative embodiments the sipe may have any desired orientation. For example, the tire may be provided with sipes 1000b that extend circumferentially. As another example, the sipes may extend axially. As will be understood by one of ordinary skill in the art, in any orientation the sipe would still appear as a substantially straight line. In still yet other alternative embodiments, rather than a straight line, the sipes may be configured to follow a U-shape, S-shape, V-shape, or Z-shape.

[0045] Figures 4 and 5 show a blade 1500 that may be used to form the sipe 1000 shown in Figures 2 and 3. As will be understood by one of ordinary skill in the art, the blade 1500 includes many of the same features of the sipe 1000 that it forms, including: a mouth portion 1505, a wave portion 1510, and a bulb portion 1515. Additionally, the blade 1500 includes three frame members 1520, 1525, 1530, with a first frame member 1520 and a second frame member 1525 flanking the mouth portion 1505, the wave portion 1510, and the bulb portion 1515, and a third frame member 1530 being adjacent to the mouth portion 1505 and extending between and interconnecting the first and second frame members 1520, 1525. The frame members 1520, 1525, 1530 only provide rigidity to the blade 1500 and do not affect the shape of the sipe 1000 formed in the tire 500. Accordingly, the frame members 1520, 1525, 1530 may have any desired configuration (e.g., any desired thickness).

[0046] Figure 6 shows an alternative embodiment of a sipe 2000. The sipe 2000 is formed in a circumferential tread 505 of a tire 500. The sipe 2000 of Figure 6 is substantially the same as the sipe 1000 of Figures 2 and 3 except for the differences described herein. Accordingly, like features will be identified by like numerals increased by a factor of “1000.”

[0047] The sipe 2000 extends along a longitudinal axis 2005 between a proximal end 2010 and a distal end 2015. The circumferential tread 505 includes a first wall 2020 and a second wall 2025 that define the sipe 2000. The sipe 2000 hasa thickness t that is defined as a distance between the first wall 2020 and the second wall 2025 along the x-axis. The sipe 2000 includes a mouth portion 2030 at the proximal end 2010, a bulb portion 2035 at the distal end 2015, and a wave portion 2040 that extends between and interconnects the mouth portion 2030 and the bulb portion 2035.

[0048] The sipe 2000 opens to an outer surface of the circumferential tread 505 at the mouth portion 2030. The thickness t of the sipe 2000 at the mouth portion 2030 gradually decreases in a direction moving from the proximal end 2010 toward the distal end 2015.

[0049] The wave portion 2040 includes a plurality of crests 2050 and troughs 2055. A period of the wave portion 2040 is constant, while an amplitude A of the wave portion 2040 decreases in a direction moving from the proximal end 2010 toward the distal end 2015. In the illustrated embodiment shown in Figure 6, the wave portion 2040 includes three crests 2050 and two troughs 2055. In comparison, the embodiment of the sipe 1000 shown in Figures 2 and 3 includes three crests 1050 and three troughs 1055. It is understood, however, that either embodiment may include a greater or fewer number of crests or troughs.

[0050] The thickness t of the sipe 2000 at the bulb portion 2035, in general, gradually increases in a direction moving toward the distal end 2015. The circumferential tread 505 further includes a curved bottom surface 2045 that further defines the sipe 2000. The curved bottom surface 2045 is provided at the bulb portion 2035 and extends between and interconnects the first and second walls 2020, 2025 at the distal end 2015 of the sipe 2015. According to this embodiment, a longitudinal axis 2060 of the bulb portion 2035 extends at a non-parallel angle with the longitudinal axis 2005 of the remainder sipe 2000. In comparison, a longitudinal axis of the bulb portion 1035 in the sipe 1000 embodiment shown in Figures 2 and 3 is coincident with the longitudinal axis 1005 of the remainder of the sipe 1000. According to one example, in the embodiment of the sipe 2000 shown in Figure 6, the longitudinal axis 2060 of the bulb portion 2035 may extend at an angle 0 of 0-45° relative to the longitudinal axis 2005 of the remainder of the sipe 2000. Although it is not shown, one of ordinary skill in the art will understandthat the blade used to form the sipe 2000 shown in Figure 6 may have many of the same features as the sipe itself, including a bulb portion extending at an angle relative to the longitudinal axis of the blade.

[0051] Figure 7 shows a method of forming a sipe in a tire. At 5000, a blade is formed. The blade extends along a longitudinal axis between a proximal end and a distal end. The blade includes a mouth portion, a bulb portion, and a wave portion that extends between and interconnects the mouth portion and the bulb portion. The wave portion includes at least one crest and at least one trough. An amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end, while a period of the wave portion is constant along the entire wave portion. The blade may include a frame member that is configured to provide rigidity to the blade. The frame member may include a first frame member and a second frame member that flank the mouth portion, the wave portion and the bulb portion. The frame member may further include a third frame member adjacent to the mouth portion that extends between and interconnects the first and second frame members. At 5005, the blade is inserted into a tread surface of the tire. The blade may be inserted before or after the tire is cured. At 5010, the blade is removed from the tread surface of the tire. In instances where the blade is inserted before the tire is cured, the blade is removed after the tire is cured.

[0052] As one of ordinary skill in the art will understand, the sipe embodiments described in this disclosure may be configured for use on a vehicle selected from the group consisting of at least motorcycles, tractors, agricultural vehicles, lawnmowers, golf carts, scooters, airplanes, military vehicles, passenger vehicles, hybrid vehicles, high-performance vehicles, sport-utility vehicles, light trucks, heavy trucks, heavy-duty vehicles, and buses. One of ordinary skill in the art will also understand that the embodiments described in this disclosure may be utilized with a variety of tread patterns, including, without limitation, symmetrical, asymmetrical, directional, studded, and stud-less tread patterns. One of ordinary skill in the art will also understand that the embodiments described in this disclosure may be utilized, without limitation, in high-performance, winter, all-season, touring, non-pneumatic, and retread tire applications.

[0053] To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” Furthermore, to the extent the term “connect” is used in the specification or claims, it is intended to mean not only “directly connected to,” but also “indirectly connected to” such as connected through another component or components.

[0054] While the present disclosure has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the disclosure, in its broader aspects, is not limited to the specific details, the representative apparatus and method, and illustrative examples shown and described. For example, the sipe shown in Figure 6 may have any of the variations described with respect to the sipe shown in Figures 2 and 3. As another example, the sipes may be provided so as to extend in a circumferential direction of the tire and be provided with a tapered mouth portion. As yet another example, the sipes may be provided so as to extend transversely and have a constant thickness at the mouth portion. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant’s general inventive concept.

Claims

CLAIMSWhat is claimed is:

1. A tire including a circumferential tread with a sipe formed therein, the sipe extending along a longitudinal axis between a proximal end and a distal end, the proximal end being at an outer surface of the circumferential tread, the sipe comprising: a mouth portion at the proximal end; a bulb portion at the distal end; and a wave portion that extends between and interconnects the mouth portion and the bulb portion, the wave portion including at least one crest and at least one trough, wherein an amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end.

2. The tire according to claim 1, wherein a period of the wave portion of the sipe is constant along the entire wave portion.

3. The tire according to claim 1, wherein the circumferential tread includes a first wall and a second wall that define the sipe, the first wall being spaced from the second wall, a distance between the first wall and the second wall defining a sipe thickness, wherein the sipe thickness along the mouth portion decreases in a direction moving from the proximal end toward the distal end.

4. The tire according to claim 1, wherein the circumferential tread includes a first wall and a second wall that define the sipe, the first wall being spaced from the second wall, a distance between the first wall and the second wall defining a sipe thickness, wherein the sipe thickness along the bulb portion increases in a direction moving from the proximal end toward the distal end.

5. The tire according to claim 1, wherein the circumferential tread includes a first wall and a second wall that define the sipe, the first wall being spacedfrom the second wall, a distance between the first wall and the second wall defining a sipe thickness, wherein the sipe thickness along the wave portion is constant along the entire wave portion.

6. The tire according to claim 1, wherein the circumferential tread includes a first wall, a second wall, and a curved bottom surface that define the sipe, the first wall being spaced from the second wall, wherein the curved bottom surface is provided at the bulb portion and extends between and interconnects the first wall and the second wall.

7. The tire according to claim 1, wherein the sipe extends along a substantially straight line along a direction that is orthogonal to the longitudinal axis.

8. The tire according to claim 1, wherein a longitudinal axis of the bulb portion is coincident with the longitudinal axis of the sipe.

9. The tire according to claim 1 , wherein a longitudinal axis of the bulb portion extends at a non-parallel angle with the longitudinal axis of the sipe.

10. A method of forming a sipe in a tire, comprising the steps of: forming a blade that extends along a longitudinal axis between a proximal end and a distal end, the blade comprising: a mouth portion; a bulb portion; and a wave portion that extends between and interconnects the mouth portion and the bulb portion, the wave portion including at least one crest and at least one trough, wherein an amplitude of the wave portion decays in a direction moving from the proximal end toward the distal end; and inserting the blade into a tread surface of the tire.

11. The method of forming a sipe in a tire according to claim 10, wherein the blade further includes a frame member that is configured to provide rigidity to the blade.

12. The method of forming a sipe in a tire according to claim 11, wherein the frame member includes a first frame member and a second frame member that flank the mouth portion, the wave portion and the bulb portion, and wherein the frame member further includes a third frame member adjacent to the mouth portion and extending between and interconnecting the first and second frame members.

13. The method of forming a sipe in a tire according to claim 11, wherein a period of the wave portion is constant along the entire wave portion.

14. The method of forming a sipe in a tire according to claim 10, wherein the step of inserting the blade into a tread surface of the tire occurs before the tire is cured.

15. The method of forming a sipe in a tire according to claim 10, wherein the step of inserting the blade into a tread surface of the tire occurs after the tire is cured.

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