Tires with ribs made of thermoplastic elastomer

Abstract

A tire (10) is provided having a plurality of circumferential ribs (12) made of a thermoplastic elastomer and having a height (h) extending in the thickness direction and between 3 mm and 6.5 mm, including both values. The thermoplastic elastomer has an average stiffness G* measured at 40°C under a stress of 0.7 MPa. Each of the ribs (12) has a height-to-average stiffness ratio controlled as follows: (h / G*) < 9 mm / MPa.

Description

Technical Field

[0001] The subject matter of this invention relates to a tire having ribs made of thermoplastic elastomer. More specifically, this application relates to a tire having thermoplastic elastomer ribs that are short enough to have rolling resistance performance close to that of a tire having a ground contact tread made of standard tread rubber. Background Technology

[0002] When the tread on a tire is exhausted, it is known to replace the tread with new tread so that the tire carcass can be reused. One way to replace the tread is to produce a pre-cured tread, the size of which is suitable for the specific tire being retreaded. The exhausted remaining tread can be removed, and the new tread can be attached to the carcass via a curing process. In this regard, uncured rubber can be placed on the carcass, and the new tread can be placed on the uncured rubber. An autoclave can be used to cure the adhesive layer, so that the new tread is attached to the carcass. In an alternative method, the new tread provided can be uncured and placed on a used carcass. The product can then be placed in a mold that imparts a structure to the new tread and cures it into part of the resulting tire.

[0003] While it's possible to add new tread to existing tires, such processes require presses, molds, autoclaves, or other equipment capable of curing parts of the product. This equipment can represent a significant investment in a retreading facility and can be labor-intensive. Furthermore, these techniques may require producing new treads specifically designed to fit onto existing tires. Dedicated flat or round molds must be produced for each tire size, and this additional tooling increases the cost and complexity of retreading. Adding new tread to an existing tire carcass with the same construction as the worn tread also increases the cost of the retreading process. Attached Figure Description

[0004] Referring to the accompanying drawings, the complete and feasible disclosure of the invention for those skilled in the art, including its best mode, is set forth in the specification, wherein:

[0005] [ Figure 1 ]

[0006] [ Figure 1 [ ] is a cross-sectional view of a tire with worn tread.

[0007] [ Figure 2 ]

[0008] [ Figure 2 ]yes[ Figure 1 The tires, in which the worn tread is removed to expose the liner.

[0009] [ Figure 3 ]

[0010] [ Figure 3 ]yes[ Figure 2 The tire has ribs applied to the liner.

[0011] [ Figure 4 ]

[0012] [ Figure 4 [This is a three-dimensional view of ribs formed by strips of multiple thermoplastic elastomers.]

[0013] [ Figure 5 ]

[0014] [ Figure 5 [Illustration] is a three-dimensional view of a rib with a groove pattern extending from the outer surface into the rib.

[0015] [ Figure 6 ]

[0016] [ Figure 6 [Illustration] is a cross-sectional view of a tire with ribs attached to the tread rubber via an adhesive.

[0017] [ Figure 7 ]

[0018] [ Figure 7 [Illustration] is a cross-sectional view of a tire having ribs attached to the tread rubber via a curing process using connecting rubber.

[0019] [ Figure 8 ]

[0020] [ Figure 8 [This is a three-dimensional view of a non-pneumatic tire with ribs made of thermoplastic elastomer applied to it.]

[0021] [ Figure 9 ]

[0022] [ Figure 9 [ ] is a graph showing the relationship between temperature and the tan(δ) value of the thermoplastic elastomer that can be used in the rib.

[0023] [ Figure 10 ]

[0024] [ Figure 10 [ ] is a graph showing the stiffness G* value of the thermoplastic elastomer that can be used in the rib, which is a curve of temperature.

[0025] [ Figure 11 ]

[0026] [ Figure 11 [ ] is the tan(δ) / G* of the thermoplastic elastomer that can be used in the rib, representing wet braking. (1 / 3) A graph of the values.

[0027] [ Figure 12 ]

[0028] [ Figure 12 [ ] is a graph of the percentage of deformation versus the rolling resistance of the thermoplastic elastomer that can be used in the rib at 23°C.

[0029] The same or similar reference numerals are used in different accompanying drawings to represent the same or similar features. Detailed Implementation

[0030] Reference will now be made in detail to embodiments of the invention, with one or more examples of embodiments illustrated in the accompanying drawings. Each example is provided to illustrate the invention and is not intended to limit the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to obtain a third embodiment. The invention is intended to include these and other modifications and variations.

[0031] The present invention provides a tire 10 having a plurality of circumferential ribs 12 made of a thermoplastic elastomer and having a height (h) 14 ranging from 3 mm to 6.5 mm and including both values. The thermoplastic elastomer used has an average stiffness G* measured at 40°C under a stress of 0.7 MPa. To achieve the desired rolling resistance of the tire 10, the size of the thermoplastic ribs 12 is further configured such that the ratio of their height to average stiffness is controlled by the inequality (h / G*) < 9 mm / MPa. The tire 10 is configured such that the ribs 12 are relatively short and made of a more flexible material, but have similar rolling resistance to a tire 10 that includes conventional tread rubber in its ground contact portion. In some arrangements, the ribs 12 may be unfeatured, and in other arrangements, they may have decorative features on the outer surface 18, or may include sipes 40 or other features extending from the outer surface 18 but not extending throughout the entire height (h) 14 of the ribs 12. When ribs 12 are added to an existing tire carcass 90 via a retreading process, the construction of ribs 12 differs from that of the originally manufactured tire. Ribs 12 can be attached to the tire carcass 90 in various ways, such as by thermoplastic welding, adhesives, or via a curing process. Using shorter ribs 12 made of a more hysteretic material allows the resulting tire 10 to have rolling resistance comparable to that of a tire 10 with conventional tread rubber 12.

[0032] [ Figure 1The diagram illustrates a tire 10, which can be a heavy-duty truck tire for 18-wheeled vehicles, garbage trucks, fire trucks, school buses, or box trucks. Tire 10 can be a steering tire, drive tire, trailer tire, or all-position tire. Tire 10 can be a light truck tire or a bus tire. Tire 10 includes an outer tire / carcass 90 on which a wear tread 36 is provided. The lateral / axial direction 26 of tire 10 is parallel to the central axis 34. The radial direction 28 (also referred to as the thickness direction 28) of tire 10 is perpendicular to the central axis 34, and the tread 36 is positioned further away from the central axis 34 in the thickness direction 28 than the carcass 90. The tread 36 extends fully around the carcass 90 in the longitudinal direction 24 of tire 10 and surrounds the central axis 360 degrees. The wear tread 36 has a series of circumferential grooves and ribs provided thereon and can have any design, and can additionally or alternatively have lateral grooves, sipes, notches, blocks, and any other construction. Although shown as a truck tire 10, it should be understood that this is for illustrative purposes only, and in other embodiments, tire 10 may be a bus tire 10.

[0033] Tire 10 has a crown 16 that engages with the road surface, and a pair of sidewalls 96, 98 extending from the crown 16 in a thickness direction 28 and separated from each other in a lateral direction 26 on opposite sides of tire 10. In the thickness direction 28, a first bead 100 is located at the end of the first sidewall 96, and a second bead 102 is located at the end of the second sidewall 98. Each of the first beads 100 and 102 includes a bead core composed of steel bars and filler rubber. The bead core with bars serves to hold the tire 10 on the rim and maintain its strength to withstand the internal stresses from inflation on the rim to prevent slippage. In some embodiments, the bead core is surrounded by a winding structure that may be made of nylon. The steel bars shown are single pieces and have a rectangular cross-sectional shape. This single piece can actually be a plurality of bars arranged together in a rectangular shape.

[0034] Tire 10 includes an organization designated as a reinforcing ply 104, which is located within a first bead 100 and extends through a first sidewall 96 and a crown 16 into a second sidewall 98 and a second bead 102. The reinforcing ply 104 is wound around a first bead core and has portions that may be referred to as return ply, which are embedded within the bead filler of the first bead 100. The opposite ends of the reinforcing ply 104 are similarly wound around filler rubber and steel bars in the second bead 102 and terminate within the bead filler of the second bead 102. The reinforcing ply 104 provides strength and flexibility to tire 10 and is a support structure for bearing the load of tire 10 at inflation pressure. The reinforcing ply 104 is a composite material comprising metal cords and a compound.

[0035] Another element of the tire 10 extending from the first bead 100 to the second bead 102 is an inner liner 82, which is inside the first bead 100 and forms part of the outer side of the first bead 100, extending to the sidewall 96. The inner liner 82 then extends in the lateral direction 26 across the entire inner side of the crown 16, and then extends into the inner side of the second sidewall 98, forming part of the outer surface of the second bead 102. The inner liner 82 in the second bead 102 is arranged in a mirror manner similar to its presence in the first bead 100. The inner liner 82 is made of a fluid-impermeable material, such that fluid between the tire 10 and the rim is retained therein to maintain the inflation pressure of the tire 10. The inner liner 82 controls air retention, has low-temperature crack resistance, and good resistance to flexural fatigue. The inner liner 82 can be made of a single layer or can be multilayered. The inner liner 82 forms the inner and outer surfaces of the sidewalls 96 and 98.

[0036] The first sidewall 96 has a tread wall 84 located at the axial end of the tire 10 and extending from the first sidewall 96 into the crown 16. The tread wall 84 is made of a different rubber composition than the rest of the first sidewall 96 and forms part of the outer surface of the tire 10. The tread wall 86 is located on the opposite end of the tread rubber 88 in the transverse direction 26 and joins the second sidewall 98, and may be mirror-image and configured identically to the tread wall 84 discussed. The tread walls 84 and 86 are made of a different material than the tread rubber 88, and their hysteresis differs from that of the tread rubber 88.

[0037] The tread 16 includes a buffer layer 92 that sits atop the reinforcing ply 104 and provides a flat surface on which the belt layer 94 may be disposed. The buffer layer 92 is made of rubber and joins the reinforcing ply 104, belt layer 94, belt edge layer 112, and belt edge layer 114. The belt layer 94 is located within the tread 16 and consists of three belts. Although the belt layer 94 is shown as comprising three belts, in other embodiments, any number of belts may be present in the belt layer 94. The belts of the belt layer 94 provide reinforcement in the tread 16 to improve wear and cornering ability. The steel belt allows the tire 10 to maintain its shape. The belt edge layers 112 and 114 act as wedges between the belt layer 94 and the tread rubber 88 to dampen stress and provide durability for the tire 10. The radial centerline 106 is located at the midpoint of the tire 10 in the lateral direction 26, and all the belts of the belt layer 94 extend across the radial centerline 106 such that their lateral midpoints are also located at the radial centerline 106, and that half of their width is located on one side of the lateral centerline 106 in the lateral direction 26.

[0038] The crown 16 includes a tread rubber 88 that serves as a base tread layer, located below and bonded to the liner 22 in the thickness direction 28, and bonded to the belt layer 94. The tread rubber 88 extends along most of the crown 16 in the lateral direction 26. The tread rubber 88 layer may be made of a material that minimizes heat generated from the steel belt in the tread 36 and belt layer 94. The tread rubber 88 may also act as an oil migration barrier, providing desired tackiness and low hysteresis. However, these properties can be eliminated or modified as needed in various tires 10. The liner 22 bonds the tread rubber 88 and the tread 36 and is located between these two components in the thickness direction 28. The liner 22 is made of a thermoplastic elastomer and has a left end side and a right end side in the lateral direction 26. The liner 22 may initially be attached to the tread 36 and the tread rubber 88 via a conventional curing process, in which heat and pressure in a mold are used to bond these components together. The tread 36 is located on top of the liner 22, such that the grooves of the tread 36 have a bottom made of the tread 36, rather than a bottom made of the liner 22 itself, so that the liner 22 is not exposed, but completely covered from the left end side to the right end side. [In [ Figure 1 In the embodiment shown, some areas of the liner 22 near the left end side 38 and the right end side 40 are not covered by the tread 36, but this is not necessarily the case in other configurations of the tire 10.

[0039] The tread 36 may be worn to the point where it reaches the end of its service life. Alternatively, the tread 36 may have abnormal wear, making it desirable for the owner of the tire 10 to replace it. Instead of discarding the tire 10, the tire 10 can undergo a retreading process, in which new tread is added to the used current tire carcass 90 to extend the life of the tire 10. To retread the tire 10, the worn tread 36 is ground off, so that it is removed to expose the liner 22, as [ Figure 2 As shown in the diagram. The exposed liner 22 is the outer surface of the tire 10 and is the portion of the tire 10 furthest from the central axis 34 in the thickness direction 28. The liner 22 has a liner width extending from the left end side to the right end side in the lateral direction 26. If sufficient liner 22 is present, the sculpting element 10 can be applied. However, if some liner 22 is removed in the process, or if additional liner 22 is required, additional thermoplastic elastomer can be added to the existing thermoplastic elastomer of the liner 22 to achieve the desired level of liner 22. Adding this additional thermoplastic elastomer to the existing liner 22 is an optional step in this method.

[0040] Rib 12 is attached to gasket 22 via thermoplastic welding, such that the ground contact portion of rib 12 is located outside gasket 22 in the thickness direction 28. Figure 3The diagram shows a rib 12 attached to a liner 22, forming a new tread on the used tire carcass 90. The rib 12 has an outer surface 18, which is the surface of the rib 12 furthest from the central axis 34 in the thickness direction 28, and is the ground contact portion of the rib 12. Due to the flexibility and suppleness of both materials, known welding processes for attaching two metals together are not used for attaching the liner 22 and the rib 12. Thermoplastic welding can be used to attach the thermoplastic elastomers of the rib 12 and the liner 22 using heated tool welding, laser welding, electromagnetic welding, or non-contact infrared welding. Thermoplastic welding introduces heat into the weld area to attach components 12 and 22, and in some instances, this heat can be generated by mechanical motion. Linear vibration can be used after the two components 12, 22 are brought into contact under pressure. In other instances, rotary welding or ultrasonic welding can be used as thermoplastic welding techniques to join components 12 and 22. In other examples, external heat sources from hot plate welding, hot rod welding, pulse welding, hot gas welding, or extrusion welding can be used as thermoplastic welding processes to attach the two components 12 and 22. Electromagnetic welding, induction welding, high-frequency welding, or infrared welding using resistance implantation can be used as thermoplastic welding techniques to attach components 12 and 22. Furthermore, the thermoplastic welding used to attach components 12, 22 to each other can be laser welding, in which a focused, strong radiation beam is used to melt the thermoplastic elastomer in components 12, 22 at the joint area, so that rib 12 is attached to pad 22.

[0041] Therefore, thermoplastic welding thermally welds the thermoplastic elastomer of the liner 22 to the thermoplastic elastomer constituting the rib 12 without the need for a curing system to cure the connection between the rib 12 and the liner 22, as is the case in known cold retreading processes. Thus, a press or autoclave is not required to attach the rib 12 to the liner 22. The rib 12 can be directly extruded onto the liner 22, and then thermally welded after the ribs are formed by extrusion. Alternatively, the rib 12 can be formed in separate locations via an extrusion process and then conveyed to the tire 10 and applied to the liner 22.

[0042] Rib 12 is generally indicated by reference numeral 12 and described in more detail using reference numerals 50, 52, 54, 56, and 58. First rib 50 is located on the left end side of liner 22 and is able to cover that left end side. The width of first rib 50 is less than the width of liner 22 and is positioned at a point on liner 22 such that the first rib serves as the first shoulder rib of tire 10. Liner 22 has a liner length that is the total length of liner 22 in the longitudinal direction 24 and extends completely around the central axis 34 in the longitudinal direction 24. The length of first rib 50 in the longitudinal direction 24 is the same as the length of liner 22, because it also extends completely around the central axis 34 in the longitudinal direction 24. It should be understood that these lengths are measured in degrees, not in millimeters or other units of length, because these components 22, 50 are designed to extend around the central axis 34 and are located at different distances from the central axis 34 in the thickness direction 28, such that they will have the same degree of extension but different units of length.

[0043] The first rib 50 extends to completely surround the gasket 22 in the longitudinal direction 24, such that it can contact itself from one end to the other. A plurality of ribs 12 may be produced in the same manner as the first rib 50 and may be attached to the gasket 22 via thermoplastic welding to form a shape such as […]. Figure 3 The tread shown is illustrated. In this respect, the second rib 52 is made of thermoplastic elastomer and is attached to the liner 22 via thermoplastic welding. The length of the second rib 52 is the same as the length of the liner 22, since both lengths extend by the same amount (360 degrees) around the central axis 34. The width of the second rib 52 is less than the width of the liner 22, and in some instances may be the same as the width of the first rib 50. The second rib 52 is spaced apart from and does not contact the first rib 50, and is positioned as the first intermediate rib of the tread of the tire 10. The space between the first rib 50 and the second rib 52 forms a circumferential groove 60, which is a shoulder groove of the tread, and the bottom 62 of the shoulder groove 60 is the top of the liner 22, so that the bottom is not covered by any rib 12 of the tread and is exposed. The circumferential groove 60 is defined by the first rib 50, the second rib 52, and the liner 22.

[0044] A radial centerline 106 exists at the midpoint of the tire 10 in the lateral direction 26. A third rib 54 is located on the liner 22 at the radial centerline 106, such that in the lateral direction 26, half of the third rib 54 is on one side of the radial centerline 106, and the other half is on the other side. The remaining ribs 12 in the tread 10 include the third rib 54, the fourth rib 56, and the fifth rib 58, and these elements can all be constructed in the same manner as the first rib 50. The third rib 54, the fourth rib 56, and the fifth rib 58 can all be made of thermoplastic elastomer designed for bonding with the road surface, and can be the same material as the first rib 50 and the second rib 52. The third rib 54, the fourth rib 56, and the fifth rib 58 all comprise thermoplastic elastomer and are thermoplastically welded to the liner 22. The third rib 54, the fourth rib 56, and the fifth rib 58 all extend around the central axis 34 by the same amount as each other and as the other ribs 50 and 52, and the length of these ribs is the same as the length of the pad, since all these elements are completely 360 degrees around the central axis 34. Furthermore, the width of the third rib 54, the fourth rib 56, and the fifth rib 58 is less than the width of the pad 22.

[0045] The center rib 54 is located at the center of the tread, such that the radial centerline 106 is located within the center rib 54. The inner and outer orientations described herein are based on this radial centerline 106, wherein the inner orientation means that an object is positioned toward or closer to the radial centerline 106 in the lateral direction 26, and wherein the outer orientation means that an object is positioned further away from or moves away from the radial centerline 106 in the lateral direction 26.

[0046] Various ribs 50, 52, 54, 56, and 58 can be thermoplastically welded to the bushing 22 to attach them to the tire 10. A third rib 54 forms the center rib of the tread and is spaced apart from and does not engage with the second rib 52 in the lateral direction 26. A first center recess is formed between the second rib 52 and the third rib 54, and the bottom of the first center recess is defined by the exposed bushing 22, which is not covered by any rib 12. On the opposite side of the third rib 54 in the lateral direction 26 is a fourth rib 56, which is spaced apart from and does not engage with the third rib 54. Two ribs 54 and 56 form a second center recess on the side of the radial centerline 106 opposite to the first center recess, and the bottom of the second center recess is defined by the exposed bushing 22. A fifth rib 58 is positioned on and above the right end side and forms the second shoulder rib of the tread. The fifth rib 58 is spaced apart from and does not engage with the fourth rib 56, and forms a second shoulder groove with the fourth rib and the exposed liner 22. The combined width of all ribs 50, 52, 54, 56, and 58 is less than the width of the liner 22. The five ribs 50, 52, 54, 56, and 58 form the tread on the used tire carcass 90, allowing the tire carcass 90 to be reused.

[0047] Ribs 50, 52, 54, 56, and 58 can all be the same size and shape, or their size and shape can differ in other embodiments. This method eliminates a curing step that would otherwise be used to attach the new tread to the used tire carcass 90. The retreading facility can have a reduced variety of rib sizes 12 to retread all tire 10 sizes because a dedicated, precisely sized tread is not required for each tire 10 size and type. The retreading facility does not need an autoclave or other curing equipment to attach the new tread to the tire carcass 90 because thermoelectric welding is used as the attachment step.

[0048] As described above, rib 12 is made of thermoplastic elastomer. In some embodiments, rib 12 is made entirely of thermoplastic elastomer without any other materials. Thermoplastic elastomer is sometimes referred to as thermoplastic rubber and is a physical mixture of copolymers or polymers consisting of materials that have both thermoplastic and elastomer properties. When constituting a physical mixture of polymers, the mixture may include both plastic and rubber materials. Ribs 12 may be manufactured with standardized features at the center, such as sipes, blocks, notches, or other construction elements. These numerous ribs 12 can be shipped to dealers or retreading facilities near customers. A variety of ribs 12 of different widths may be provided only for use with tires 10 of different widths. Five or six different variations of ribs 12 may also be provided to serve as one or more intermediate ribs. The provided ribs 12 may have the same cross-sectional shape, or some ribs may have a rounded side while others have two straight sides, such that some ribs can be used as shoulder ribs, while ribs with two straight sides can be used as intermediate and center ribs.

[0049] Rib 12 can be a single piece of thermoplastic elastomer, which is extruded or otherwise produced as a monolithic element. The length of rib 12 will be greater than its width or height (h). Rib 12 can be provided in various other forms. Figure 4 An embodiment of the construction of rib 12 is shown, wherein the rib is made of a plurality of smaller strips 40. These strips 40 have the same length and width as the resulting rib 12, but are less tall. Each strip 40 is made of thermoplastic elastomer, and five strips 40 are stacked on top of each other to form the resulting rib 12. The strips 40 are attached to subsequent strips 40 in the stack via thermoplastic welding to form the resulting rib 12 constructed via thermoplastic welding. Although five strips 40 are shown, in other embodiments, any number of strips 40 may be present in the rib 12.

[0050] Ribs 12 may have a completely featureless outer surface 18, and when placed in a tire 10, such ribs 12 form a tread known as a smooth surface, but circumferential grooves will be present between the ribs 12 forming the outer surface 18. In other embodiments, the outer surface 18 may have decorative features thereon. In yet another embodiment, the ribs 12 may have construction features such as notches or sipes 42. [See reference...] Figure 5 The diagram illustrates one embodiment of the rib 12, wherein sipes 42 extend from the outer surface 18 into the rib 12. The sipes 42 are present within the ground contact outer surface 18 and are gaps within the rib 12, having a length of 2 mm or less in the longitudinal direction. Continuous sipes 42 may be equidistant from each other along the length of the rib 12. The width of the sipes 42 in the lateral direction 26 extends completely across the entire width of the tread 12. Regarding the depth of the sipes 42, its depth in the thickness direction 28 is less than the height (h) 14. The extension of the sipes 42 in the thickness direction 28 is 2 mm or less. In some embodiments, the depth of the sipes 42 in the thickness direction 28 is less than or equal to half the height (h) 14.

[0051] [ Figure 6 Another embodiment of tire 10 is shown, in which rib 12 is again made of thermoplastic elastomer. However, the construction of tire 10 differs from the previously discussed construction in that the liner 22 is absent. The liner 22 may be removed during the grinding process to prepare tire 10 for retreading, or the liner 22 may never be present in the initially formed tire 10. In any case, in the absence of the liner 22, rib 12 is attached to the tread rubber 88 in the crown 16. Ribs 12 are attached by using adhesive 44, which attaches each of ribs 50, 52, 54, 56 to the tread rubber 88. In the disclosed embodiment, there are four ribs 50, 52, 54, 56, instead of five as previously disclosed. It should be understood that in other embodiments, any number of ribs 12 may be present within tire 10. Ribs 12 are spaced apart from each other and do not engage with each other, such that circumferential grooves are formed between successive ribs 12, and these grooves have a bottom defined by the tread rubber 88 rather than by the thermoplastic elastomer or adhesive 44 of the ribs 12. The circumferential groove 60 is defined by continuous ribs 50, 52 and tread rubber 88 exposed at the bottom 62. Other grooves in the tread can be formed in a similar manner. The adhesive 44 does not extend across the entire width of the tread rubber 88 in the lateral direction 26, but is only present at the location of the rib 12. In this respect, the bottom 62 of the groove 60 does not include the adhesive 44, but is free of adhesive; however, it should be understood that some adhesive 44 may seep out or otherwise be present on the bottom 62 and may form part of the sidewall of the groove 60, especially at the contact point between the rib 12 and the tread rubber 88.

[0052] [ Figure 7 Another tire 10 according to the invention is disclosed, characterized in that the rib 12 is made of a thermoplastic elastomer. In this embodiment, the attachment of the rib 12 to the tire carcass 90 is performed via a curing process. In this respect, the liner 22 is absent because it is worn away during retreading or is not present in the initially formed tire 10. Strips of connecting rubber 46 (which is uncured rubber) are placed on the cured tread rubber 88 at the desired location of the rib 12. The uncured connecting rubber 46 does not extend across the entire width of the tread rubber 88 in the lateral direction 26, but is intermittently spaced from the continuous strips of connecting rubber 46. The rib 12 is placed on the strips of connecting rubber 46, and then the assembly is placed in a mold or autoclave to cure the connecting rubber 46. This curing causes the rib 12 to be attached to the tread rubber 88 via the now cured connecting rubber 46. Therefore, the resulting tread is characterized by ribs 12 that extend completely around the tire 10 in the longitudinal direction 24 and are spaced apart from and do not engage with the continuous ribs 12 in the transverse direction 26, such that circumferential grooves 60 are formed between the ribs 12 completely around the longitudinal length of the tire 10. In the thickness direction 28, the height 14 is greater than the height of the connecting rubber 46.

[0053] [ Figure 8 The illustrated tire 10 is a non-pneumatic tire 10, wherein the carcass 90 has a support structure 66, which is a series of spokes attached to a hub 70 at their inner ends and to a shear beam 68 at their outer ends. A central axis 34 extends through the center of the hub 70 and is the innermost portion of the tire 10 in the thickness direction 28. A liner 22 is included on the shear beam 68, and when the tread on the shear beam 68 wears to the end of its service life, it can be replaced with one or more ribs 12. These ribs 12 can be attached to a thermoplastic elastomer of the liner 22 using techniques as previously discussed. Multiple ribs 12 can be applied to the liner 22 to form the tread. Thus, the tire 10 to which the ribs 12 are attached can be a pneumatic tire 10 as previously described, or a non-pneumatic tire 10 as currently discussed. The tire 10 can also be a solid tire 10, which is sometimes found on construction vehicles, material handling vehicles, and delivery trucks. The ribs 12 formed on the tire 10 are featureless and number five, thus forming intermittent circumferential grooves, and the tire 10 can be described as having a smooth surface. Although described as being used with retreading old tires 10, this method can also be used to form tires 10 that can be produced by original equipment manufacturing and put into new vehicles.

[0054] Hysteresis can be measured by the tan(δ) value of the rubber constituting rib 12. The loss factor "tan(δ)" is a dynamic property of the rubber compound. It is measured on a viscosity analyzer (Metravib VA4000) according to standard ASTM D5992-96. The response of a test sample consisting of two cylindrical spheres (each 2 mm thick and 1 cm in diameter) was recorded. This test sample was made from a sample taken from the midway point of the tire at the height of the region of interest, which was thick enough to form the test sample as close to the equatorial plane as possible. The sample was subjected to a simple alternating sinusoidal shear load at a frequency of 10 Hz at a temperature of 60 °C. The frequency sweep covered the amplitude of deformation from 0.1% to 25% peak-to-peak (on the outward cycle) and then from 25% to 1% peak-to-peak (on the return cycle). The results used here are the loss factor tan(δ) and the complex dynamic shear modulus. The complex dynamic shear modulus is expressed as "G*25" for a 25% strain applied during the test. The maximum value of tanδ observed during the outward loop is denoted as "maximum tan(δ)".

[0055] Modulus, sometimes called complex shear modulus, can be denoted by the symbol G*. The modulus G* of a particular material can be measured at 60 degrees Celsius and can be expressed in megapascals (MPa). The dynamic property (G*) can be measured according to ASTM D5992-96 on a Metravib VA400 viscoelastic analyzer testing system. The response of a vulcanized material sample (a dual shear geometry, where each of the two 10 mm diameter cylindrical samples is 2 mm thick) can be recorded as subjected to a constant alternating single sinusoidal shear stress of 0.7 MPa over a temperature sweep from -60 °C to 100 °C at a frequency of 10 Hz, with the temperature gradually increasing at 1.5 °C / min. The shear modulus G* at 40 °C can be captured. As used herein, unless otherwise specified, the shear modulus G* at 40 °C is determined according to ASTM 5992-96 and expressed in MPa. As used herein, the term "modulus" or "modulus G*" may also be referred to as, or is known as, the complex shear modulus G* at 40°C, or the shear modulus G* at 40°C, or the complex shear modulus G* at 40°C. Where ASTM 5992-96 may require measuring G* at different temperatures (e.g., at 60°C), the measurement at 40°C can be replaced by the same method to derive the G* measured at that temperature.

[0056] Using ribs 12 made of thermoplastic elastomers may result in the tire 10 having different performance than a tire 10 with a tread made of standard tread rubber. This may be because thermoplastic elastomers are more flexible than tread rubber, and if they have the same height as the tread rubber, the tire 10 may not have the same good rolling resistance performance. To design a tire 10 with some performance characteristics that are the same as or even better than those of a tire 10 made of tread rubber, the ribs 12 may be designed to have a height (h) 14 that is not as high as that of a tire 10 that includes the tread rubber as its outer surface 18. In some embodiments, the height (h) 14 may be between 3 mm and 6.5 mm and include both of these values. In other embodiments, the height (h) 14 may be between 3 mm and 4 mm, 3 mm and 5 mm, 3 mm and 6 mm, 6 mm and 6.5 mm, 5 mm and 6.5 mm, 4 mm and 6.5 mm, 4 mm and 6 mm, or 5 mm and 6 mm and include these values. To further define the tread design, the stiffness of the thermoplastic elastomer can be considered to achieve the desired performance characteristics of the tread 10. The stiffness is represented by the G* value at 40°C and a stress of 0.7 MPa. The height (h) 14 of the rib 12 can be further refined by selection based on the following inequality:

[0057]

[0058] [ Figure 9 The diagram shows temperature versus tan(δ), in degrees Celsius, for both a tire 10 with thermoplastic elastomer incorporated into the rib 12 and a tire 10 with conventional tread rubber incorporated as the ground contact element instead of the rib 12 made of thermoplastic elastomer. The conventional tread rubber tire 10 may be a Michelin tire manufactured by Michelin North America, Inc. ® Primacy ® 4 Grand Touring summer tires, the company has an office at 1 Parkway S, Greenville, South Carolina, 29615, USA. The reference tire 10 is in […]. Figure 9 It is designated as PCY 4 OE in []. As described herein, the tire 10, which includes a thermoplastic elastomer in rib 12, is in [ Figure 9 The two tires 10 were designated as "subjects". The tan(δ) values ​​of both tires 10 were recorded at different temperatures, and the PCY 4 OE reference tire exhibited higher hysteresis corresponding to a higher tan(δ) value in the temperature range of -12°C to 12°C compared to the test tire 10. The test tire 10 had higher hysteresis and therefore higher tan(δ) at temperatures outside this range.

[0059] exist[ Figure 10In this study, the stiffness of the materials constituting the test tire 10 and the PCY 4 OE tire 10 were compared at different temperatures. Stiffness was measured as a value G* and expressed in MPa, and [ Figure 10 The results show that PCY 4 OE has a higher G* than the tested tire 10 at all temperatures.

[0060] Figure 11 It is also related to the temperature and expression of the test tire 10 and the reference tire 10. The curve is referenced from the tire or PCY 4 OE. Figure 11 The tan( used The values ​​were measured at 10% deformation, and the G* values ​​were measured at different degrees Celsius under a stress of 0.7 MPa. Figure 9 and Figure 10 The numbers appearing in the table represent the tan(π / 2) of the test tire and reference tire extracted at each temperature. Values ​​and G* values, and substitute them into the expression. To draw Figure 11 The two curves shown. Figure 11 The graph shows the wet braking performance of the materials of the test tire and reference tire 10. Specifically, the wet braking performance of tire 10 is the area under the curve obtained over a temperature range of -8°C to 20°C. Figure 11 In the test, tire 10 has a higher curve than reference tire 10, and therefore has a larger area 110 below the curve within this temperature range. The wet braking performance of tire 10 is measured as an average integral from -8°C to 20°C. Furthermore, in some embodiments, the average integral may be greater than 0.4. In other embodiments, the average integral (which is an area of ​​110) may be greater than 0.37, 0.38, 0.39, 0.35, 0.33, 0.41, 0.42, 0.43, or 0.44. The wet grip performance of the test material may be superior to that of the reference material.

[0061] Figure 12 The rolling resistance of tire 10 is shown. Figure 12 The values ​​were obtained at a temperature of 23°C. For both the test material and the reference material in tire 10, the tan(θ) values ​​at 23°C were plotted on a graph under various deformations. Refer to tire 10 or PCY 4 OE. The deformation value on the x-axis represents the percentage deformation of the tested material. The extreme value on the rightmost side of the x-axis is 100% deformation, and the lowest value recorded on the leftmost side of the x-axis is 0.01% deformation of the sample. A higher tan( The value of tan( ) indicates a larger rolling resistance. Because tan( The rolling resistance varies with different deformation percentages. To design a tread with thermoplastic elastomer that has equivalent rolling resistance to the reference tire 10, tan( ) should be selected. A single value in the tan( ) value. The value can be the maximum tan( ) within the deformation range of 0.01% to 100%. ), and in [ Figure 12 In the figure, the material composition of the test tire 10 is 0.22, and the material composition of the reference tire 10 is 0.16. Therefore, the material of the test tire 10 will produce higher rolling resistance compared to the material constituting the reference tire 10.

[0062] At a tire operating temperature of 40°C, the material of the tested tire 10 is expressed as tan( The stiffness G* of the reference tire 10 is 0.6 MPa, and the stiffness of the reference tire 10 material is 0.86 MPa. If the reference tire 10 has a height of 7.5 mm, and if it is desired to provide a height (h) 14 of the test tire 10 with equivalent rolling resistance, then the height (h) 14 can be calculated by solving the following equation: Height (h) 14 = Reference height × (Test G* / Reference G*) = 7.5 mm × (0.6 MPa / 0.86 MPa) = 7.5 mm × (0.697) = 5.2 mm. The tire 10 may be provided with ribs 12 having a height (h) 14 of 5.2 mm, such that the resulting rolling resistance is equivalent to that of a standard rubber tread tire 10 without thermoplastic elastomer in the tread portion of its contact surface.

[0063] The rolling resistance of the designed tire 10 does not need to be exactly the same as that of the reference tire 10, but can be within 95% of that rolling resistance. An inequality that can be used to calculate the height (h) 14 of the rib 12 of the tire 10 is as follows: The largest tan( ) is the largest tan( ) of the main tire material 10 within the deformation range of 0.01% to 100%. ).

[0064] The ribs 12 formed in the resulting tire 10 can be simplified according to other designs, as they can be featureless smooth surfaces that are not as hard as the tread of standard rubber with a contact surface, but with a shorter height (h) 14 to compensate for achieving acceptable rolling resistance performance. Although described as featureless, notches can be added to the ribs 12 as needed, or any other construction features can be added to the ribs 12, and it should be understood that the ribs 12 do not need to be featureless in all embodiments.

[0065] Although the subject matter of the invention has been described in detail with respect to specific embodiments and methods, it should be understood that modifications, variations, and equivalents of such embodiments will be readily conceived by those skilled in the art upon understanding the foregoing. Therefore, the scope of this disclosure is by way of example rather than limitation, and this disclosure does not exclude obvious such modifications, variations, and / or additions to the subject matter.

Claims

1. A tire, the tire comprising: Multiple circumferential ribs extend in the longitudinal direction around a central axis, wherein the ribs are made of thermoplastic elastomer and have a height (h) that extends in the thickness direction and is between 3 mm and 6.5 mm and includes both values, wherein the thermoplastic material has an average stiffness G* measured at 40°C under a stress of 0.7 MPa. Each of the ribs described above has the following controlled height-to-average stiffness ratio: 。 2. The tire according to claim 1, wherein the thermoplastic elastomer has a plurality of tan(δ) values ​​measured at 10% deformation at different temperatures, and wherein the thermoplastic elastomer has a plurality of average stiffness G* values ​​measured at different temperatures. The thermoplastic elastomer described herein has the following wet braking properties: Average integral measured from -8℃ to 20℃ >0.

4.

3. The tire according to claim 1 or 2, wherein the thermoplastic elastomer has a maximum tan(δ) at a temperature of 23 degrees Celsius, which is the highest tan(δ) value found in the deformation range between 0.01% and 100% and including both values. The height (h) of the rib is controlled as follows: 。 4. The tire according to any one of claims 1 to 3, wherein the rib is produced by an extrusion process.

5. The tire according to any one of claims 1 to 4, wherein each of the ribs comprises a plurality of strips of the thermoplastic elastomer, the plurality of strips being thermally welded together to form the rib.

6. The tire according to any one of claims 1 to 5, wherein the tire has a liner made of a thermoplastic elastomer extending about the central axis in the longitudinal direction and in the transverse direction, wherein the ribs are attached to the liner via thermoplastic welding, wherein the ribs are spaced apart from each other in the transverse direction and do not engage with each other, such that a circumferential groove is defined between consecutive ribs in the ribs, and the bottom of the circumferential groove is defined by the liner.

7. The tire according to any one of claims 1 to 5, wherein the tire crown has tread rubber, and further comprises an adhesive for attaching the rib to the tread rubber.

8. The tire according to any one of claims 1 to 5, wherein the tire crown has a tread rubber, and further includes a connecting rubber located between the rib and the tread rubber in the thickness direction, wherein curing is used to cure the connecting rubber and the rib is mounted to the tread rubber via the connecting rubber.

9. The tire according to any one of claims 1 to 8, wherein the rib has an outer surface that is the ground contact surface of the tire, and wherein the rib does not have any gaps extending from the outer surface into the rib to a depth of more than 2 mm in the thickness direction.

10. The tire according to any one of claims 1 to 8, wherein the rib has an outer surface, the outer surface being the ground contact surface of the tire, wherein the outer surface is featureless.

11. The tire according to any one of claims 1 to 10, wherein the tire is a pneumatic tire.

12. The tire according to any one of claims 1 to 10, wherein the tire is a solid tire.

13. The tire according to any one of claims 1 to 10, wherein the tire further comprises: A support structure having spokes; and A shear beam, wherein the shear beam is located outside the support structure in the thickness direction; The ribs are located on the outside of the shear beam in the thickness direction.

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