Tire

Abstract

A tyre (1) comprises a tread band (2) in a radially outer position, on which a tread surface (3) is defined. The aforementioned tread band (2) comprises a plurality of grooves (7A, 7B), each groove comprising a first wall (71) and a second wall (72) facing each other and defining a groove width (WG). At least one of the first wall (71) and the second wall (72) comprises a plurality of protrusions (8) protruding from at least one of the first wall (71) and the second wall (72), having a protrusion width (WP), where the protrusion width (WP) is less than 20% of the groove width (WG).

Description

Technical Field

[0001] This invention relates to a tire.

[0002] More specifically, the present invention relates to a winter tire or all-season tire with improved performance (especially on snowy roads). Background Technology

[0003] Tires typically include a carcass structure formed to the circumference of a rotation axis, a belt structure applied to the carcass structure at a radially outer position, and a tread belt made of an elastomeric material superimposed on the carcass structure, the tread belt defining a tread surface intended for contact with the road surface.

[0004] The tread belt is typically defined by multiple circumferential grooves and / or lateral grooves, which define corresponding blocks that together define the tire tread pattern.

[0005] The characteristics of the tread band, especially the number and configuration of the grooves on the tread surface, primarily determine the tire's performance in terms of road behavior, particularly regarding the different possible conditions of the road surface itself.

[0006] The term "equatorial plane" in tires refers to the midplane perpendicular to the tire's axis of rotation.

[0007] The terms “radial” and “axial”, as well as the expressions “radial inside / outside” and “axial inside / outside”, are used with reference to the tire’s axis of rotation, while the terms “circumferential” and “circumferentially” are used with reference to the tire’s circumferential extension direction, i.e., the tire’s rolling direction, which corresponds to a direction located on a plane that coincides with or is parallel to the tire’s equatorial plane.

[0008] Specifically:

[0009] The term "radial direction" is used to indicate a direction substantially perpendicular to the tire's axis of rotation. The term "groove" refers to a recess formed on the tread surface, having at least a portion having a width of at least 1.5 mm between the walls defining it, referred to as the "groove width".

[0010] Preferably, the trench has a depth of at least about 5 mm, referred to as the "trench depth".

[0011] The aforementioned groove width ensures that the walls defining the grooves do not contact each other under normal driving conditions. This creates drainage channels on the tire tread surface, thereby improving tire grip during driving on wet roads.

[0012] The term "void volume" refers to the volume of tread removed to form the groove itself. In other words, the void volume of the groove is the volume between the two walls and the base of the groove.

[0013] The term "protrusion" refers to a portion of at least one wall of a trench that protrudes toward the interior of the trench.

[0014] The term "protrusion width" refers to the dimension of a protrusion measured along a direction orthogonal to the direction in which the protrusion extends. In other words, protrusion width is a measure of the portion of the wall that protrudes toward the interior of the groove.

[0015] The term "protrusion length" refers to the dimension of the protrusion measured along a direction parallel to the direction in which the protrusion extends within the groove.

[0016] The term "protrusion height" refers to the dimension of the protrusion as measured along its radial extension.

[0017] The term "protrusion volume" refers to the volume occupied by each protrusion within the corresponding groove.

[0018] The term "total protrusion volume" refers to the sum of the volumes of all protrusions within the same trench.

[0019] Patent document JP2006137231A describes a tire with protrusions, the width of which is greater than or equal to 60% of the groove width.

[0020] Patent document US2011290393A1 describes a tire comprising a tread belt having a plurality of raised elements having contact surfaces and sidewalls, wherein at least one raised element includes at least one cutout opening into two of the aforementioned sidewalls, the at least one cutout being defined by a first wall and a second wall including protrusions. The first wall includes at least one protrusion, and the second wall includes as many pairs of first and second protrusions as there are protrusions on the first wall, wherein each protrusion on the first wall is designed to cooperate through contact with a pair of first and second protrusions on the opposing second wall. However, the applicant notes that these solutions suitable for narrow cutouts are not suitable for wider grooves because the protrusions protrude so much within the groove that they tend to clog the groove, thereby reducing its cross-section and preventing water from draining through it. Summary of the Invention

[0021] The applicant addresses the problem of improving tire performance on snowy surfaces by promoting the capture and adhesion of snow within grooves carved into the tread, without reducing or even risking performance on dry or wet surfaces.

[0022] The applicant recognizes that this objective can be achieved by arranging multiple protrusions corresponding to the walls of the groove, the protrusions functioning to prevent the escape of snow trapped in the groove during tire rolling as the tire passes through the tire track area. The applicant has found that providing multiple protrusions on one or two walls of the groove, these protrusions having a protrusion width much smaller than the width of the groove itself, allows for improved snow trapping between the groove walls without significantly narrowing the latter's cross-section, thus not introducing a significant negative impact on tire performance on dry or wet surfaces.

[0023] More specifically, the applicant believes that by providing the aforementioned protrusions that slightly protrude from the walls of the grooves, a "clamping" structure is formed. When rolling on snowy ground, this structure, on the one hand, does not prevent snow from entering the grooves as it passes through the tire track area, and on the other hand, prevents snow from escaping after the grooves leave the tire track area. Thus, the snow, due to its own viscosity, is compacted layer by layer between the protrusions, remaining within the grooves even when the tire partially leaves the tire track area, where the protrusions act as mechanical barriers. In this way, tire performance on snowy surfaces is improved: in fact, the more snow trapped in each groove, the greater the friction between the snow-filled tire and the snow on the road surface, because snow-snow friction is greater than tire-snow friction.

[0024] The effects described above occur simultaneously with the slight protrusion of the protrusions within the corresponding grooves, which maintains the drainage function essentially unchanged on wet surfaces and the tread pattern's performance on dry surfaces (e.g., in terms of noise generation or wear uniformity).

[0025] In particular, in a first aspect, the present invention relates to a tire comprising a tread strip located in a radially outer position, on which a tread surface is defined.

[0026] Preferably, the aforementioned tread band includes a plurality of grooves, each groove including a first wall and a second wall facing each other and defining a groove width. Advantageously, the groove width is greater than or equal to 2 mm.

[0027] Preferably, the aforementioned groove width is less than or equal to 10 mm. Even more preferably, the groove width is between 2 mm and 10 mm (inclusive). Preferably, at least one of the first wall and the second wall includes a plurality of protrusions that protrude from the at least one of the first wall and the second wall by a protrusion width.

[0028] Preferably, the protrusion width is less than 20% of the groove width. More preferably, the protrusion width is less than 10% of the groove width.

[0029] Even more preferably, the protrusion width is less than 5% of the groove width. Advantageously, the protrusion width is much smaller than the groove width so as not to impede its cross-section during rolling, thereby allowing drainage in wet ground conditions and simultaneously acting as a mechanical barrier to promote the capture and adhesion of snow in the groove in snowy ground conditions, as described above.

[0030] The plurality of trenches includes a corresponding trench length. Additionally, the plurality of trenches have a corresponding base located radially inward between the first wall and the second wall.

[0031] The plurality of grooves have corresponding groove depths extending from the tread surface to the base. Preferably, each of the plurality of protrusions has a corresponding protrusion height in the radial direction, the protrusion height being greater than or equal to 5% of the groove depth.

[0032] Preferably, the height of the protrusion is less than or equal to 20% of the trench depth.

[0033] Even more preferably, the height of the protrusion is between 5% and 20% of the groove depth.

[0034] Preferably, the plurality of protrusions are disposed in a portion of at least one of the first wall and the second wall, the portion having a height greater than or equal to 20% of the trench depth.

[0035] Preferably, the plurality of protrusions are disposed in a portion of at least one of the first wall and the second wall, the portion having a height less than or equal to 50% of the trench depth.

[0036] Even more preferably, the plurality of protrusions are disposed in a portion of at least one of the first wall and the second wall, the portion having a height between 20% and 50% of the trench depth.

[0037] The aforementioned portion of at least one of the first wall and the second wall is located between the minimum level and the maximum level of the trench depth.

[0038] Preferably, the minimum level is greater than or equal to 10% of the trench depth.

[0039] Preferably, the minimum level is less than or equal to 30% of the trench depth.

[0040] More preferably, the minimum level is between 10% and 30% of the trench depth.

[0041] Preferably, the maximum level is greater than or equal to 40% of the trench depth.

[0042] Preferably, the maximum level is less than or equal to 70% of the trench depth.

[0043] More preferably, the maximum level is between 40% and 70% of the trench depth.

[0044] Advantageously, at least some of the protrusions are located at corresponding levels at different locations on at least one of the first and second walls.

[0045] Advantageously, in another preferred embodiment, at least some of the plurality of protrusions are aligned along at least one line substantially parallel to the tread surface.

[0046] In addition, at least some of the protrusions are arranged along multiple lines that are substantially parallel to the tread surface.

[0047] In a preferred but non-limiting embodiment, the plurality of lines comprises two to four lines.

[0048] Preferably, the protrusions arranged along the first of the plurality of lines are arranged in an alternating manner relative to the protrusions arranged along another of the plurality of lines.

[0049] Generally, each of the plurality of protrusions extends a defined protrusion length.

[0050] Advantageously, preferably, two of the plurality of protrusions are spaced apart by a defined protrusion distance.

[0051] Advantageously, the determined protrusion distance is substantially equal to the protrusion length.

[0052] Preferably, the length of the protrusion is greater than or equal to 0.5% of the total length of the plurality of grooves.

[0053] Furthermore, preferably, the length of the protrusion is less than or equal to 10% of the total length of the plurality of grooves.

[0054] More preferably, the protrusion length is between 0.5% and 10% of the groove length of the plurality of grooves.

[0055] Preferably, the ratio of the protrusion length to the protrusion width is greater than 3.

[0056] Furthermore, preferably, the ratio of the protrusion length to the protrusion width is less than 20.

[0057] Preferably, the ratio of protrusion length to protrusion width is between 3 and 20 (inclusive).

[0058] In addition, preferably, the ratio of the protrusion length to the protrusion height is greater than 5.

[0059] Preferably, the ratio of protrusion length to protrusion height is less than 10.

[0060] More preferably, the ratio of protrusion length to protrusion height is between 5 and 10 (inclusive).

[0061] Preferably, the total protrusion volume of the plurality of protrusions is greater than or equal to 0.5% of the void volume of the groove.

[0062] Furthermore, preferably, the total protrusion volume is less than or equal to 8% of the void volume of the trench.

[0063] More preferably, the total protrusion volume is between 0.5% and 8% of the void volume of the trench.

[0064] In a preferred but non-limiting embodiment, the protrusion volume is between 0.5% and 4% of the void volume of the trench.

[0065] In a preferred embodiment, the protrusions among the plurality of protrusions have an elongated shape.

[0066] Alternatively, the protrusion may have a hemispherical shape. Alternatively, the protrusion may have a basic polyhedral shape.

[0067] Preferably, the shape can be a basic cuboid. Alternatively, the shape can be elliptical.

[0068] Advantageously, in a preferred but non-limiting embodiment, the plurality of protrusions are disposed on at least one of the first and second walls corresponding to the transverse grooves in the plurality of grooves.

[0069] In a preferred embodiment, one of the plurality of protrusions is disposed on both the first wall and the second wall. Attached Figure Description

[0070] The features and advantages of the invention will be better understood from the detailed description of preferred embodiments shown by way of example, but not limitation, with reference to the accompanying drawings, in which:

[0071] Figure 1 A plan view of a portion of the tread band of a tire according to an embodiment of the present invention is shown;

[0072] Figure 2A An embodiment of the present invention is shown. Figure 1 A perspective view of a portion of a trench depicted and indicated by II, the trench having walls comprising a plurality of protrusions;

[0073] Figure 2B yes Figure 2A The second perspective view of the groove;

[0074] Figure 3A yes Figure 2A A radial cross-sectional view of this portion of the trench;

[0075] Figure 3B yes Figure 2A A magnified front view of the wall of the trench depicted in the image. Detailed Implementation

[0076] Referring to the accompanying drawings, 1 generally indicates a tire manufactured according to the present invention. Tire 1 includes a conventional tire structure that is not shown in the drawings.

[0077] Advantageously, preferably, as described above in the known art, such a structure typically includes a carcass structure toroidally formed around a rotation axis, on which a belt structure is applied in a radially outer position. The belt structure includes at least two rubber strips with reinforcing cords, typically metal reinforcing cords, arranged parallel to each other in each strip, but arranged in an intersecting position relative to the cords of adjacent strips, preferably symmetrically arranged relative to the equator of the tire.

[0078] The belt structure preferably further includes a third layer located radially outside the at least two strips of the belt structure, and the cords of the third layer are arranged circumferentially (at 0 degrees).

[0079] In addition, corresponding sidewalls are applied on the opposite side surfaces of the carcass structure at the axially outer position of the carcass structure.

[0080] In tubeless tires, there is also a radial inner layer called the liner layer, which is impermeable to ensure the tire's airtightness.

[0081] Advantageously, at the point of overlap with the belt structure, the tire 1 includes a tread belt 2 in a radially outer position, on which a tread surface 3 is defined ( Figure 1 (), designed for contact with the road surface.

[0082] In a preferred embodiment, such a tread band is preferably made of an elastic material.

[0083] Multiple grooves are formed on the tread band 2, as indicated by reference numerals 7A and 7B in the attached drawings.

[0084] Advantageously, as can be seen in the figure, especially as Figure 1 and Figure 3A As can be seen, each of the plurality of trenches includes a first wall 71 and a second wall 72 that face each other and define a trench width WG.

[0085] Advantageously, the groove width WG is greater than or equal to 2 mm. Preferably, the aforementioned groove width WG is less than or equal to 10 mm. Even more preferably, the groove width WG is between 2 mm and 10 mm (inclusive).

[0086] At least one of the first wall 71 and the second wall 72 includes a plurality of protrusions 8, which in Figures 2A-3A In the illustrated embodiment, protrusions extend from the first wall 71 and the second wall 72. Advantageously, in the case of snow-covered roads, these protrusions 8 are adapted to allow snow to be gripped and held within the grooves during tire rotation.

[0087] like Figure 3A As can be seen, these protrusions 8 project from the first wall 71 and / or the second wall 72 by a protrusion width WP, which is much smaller than the groove width WG. Preferably, the protrusion width WP is less than 20% of the groove width WG. More preferably, the aforementioned protrusion width WP is less than 10% of the groove width WG.

[0088] Even more preferably, the protrusion width WP is less than 5% of the groove width WG.

[0089] Advantageously, the protrusion width WP is much smaller than the groove width WG, so that the groove is not blocked during passage through the tire track area, thus allowing drainage in wet ground conditions. For example, the protrusion width WP can be 0.35 mm.

[0090] refer to Figures 2A-3B The plurality of grooves 7A, 7B have corresponding bases 9 located in a radially inward position between the first wall 71 and the second wall 72. The plurality of grooves 7A, 7B have corresponding groove depths DG that extend from the tread surface 3 to the aforementioned bases 9.

[0091] In the preferred embodiment shown in the figure, the plurality of protrusions 8 preferably have an elongated shape.

[0092] Alternatively, the plurality of protrusions 8 may have a hemispherical shape. Alternatively, the plurality of protrusions 8 may have a polyhedral shape. Preferably, the shape may be a basic cuboid. Alternatively, the shape may be elliptical.

[0093] refer to Figures 2A-3B Preferably, each of the plurality of protrusions 8 has a corresponding protrusion height DP in the radial direction, which is greater than or equal to 5% of the groove depth DG.

[0094] For example, the protrusion height DP can be 0.7mm.

[0095] Preferably, the aforementioned protrusion height DP is less than or equal to 20% of the trench depth DG.

[0096] Even more preferably, the protrusion height DP is between 5% and 20% of the groove depth DG.

[0097] Generally speaking, such as Figure 1 , Figure 2A and Figure 3BAs in the example, each of the multiple protrusions 8 extends a certain protrusion length LP.

[0098] For example, the protrusion could be 7mm long. (Still referencing...) Figures 2A-3B Two of the multiple protrusions 8 are separated by a certain protrusion distance PD.

[0099] Advantageously, the protrusion distance PD is approximately equal to the protrusion length LP.

[0100] For example, in the case just described, the protrusion distance can be 7mm.

[0101] Preferably, the protrusion length LP along which each of the plurality of protrusions 8 extends is greater than or equal to 0.5% of the groove length of the plurality of grooves 7A, 7B. More preferably, the protrusion length LP is less than or equal to 10% of the groove length of the plurality of grooves 7A, 7B.

[0102] More preferably, the protrusion length LP is between 0.5% and 10% of the groove length of the plurality of grooves 7A and 7B.

[0103] Advantageously, the ratio of protrusion length LP to protrusion width WP is between 3 and 20. Figure 3A Furthermore, the ratio of protrusion length LP to protrusion height DP is between 5 and 10. Figure 3B ).

[0104] Preferably, the protrusion volume of the plurality of protrusions 8 is greater than or equal to 0.5% of the void volume of the groove.

[0105] Furthermore, preferably, the volume of the protrusion is less than or equal to 8% of the void volume of the groove.

[0106] More preferably, the volume of the protrusion is between 0.5% and 8% of the void volume of the groove.

[0107] In a preferred but non-limiting embodiment, the protrusion volume is between 0.5% and 4% of the void volume of the trench.

[0108] Advantageously, such as Figure 1 As can be seen in the example, in a preferred but non-limiting embodiment, the plurality of protrusions 8 correspond to the transverse groove 7B among the plurality of grooves 7A, 7B.

[0109] Preferably, a plurality of protrusions 8 are disposed in a portion of at least one of the first wall 71 and the second wall 72, the portion having a height H greater than or equal to 20% of the trench depth DG. Figure 2B-3B ).

[0110] Preferably, a plurality of protrusions 8 are disposed in a portion of at least one of the first wall 71 and the second wall 72, the portion having a height H less than or equal to 50% of the trench depth DG. Figure 2B-3B ).

[0111] More preferably, a plurality of protrusions 8 are disposed in a portion of at least one of the first wall 71 and the second wall 72, the portion having a height H between 20% and 50% of the groove depth DG. Figure 2B-3B ).

[0112] like Figure 2B and Figure 3B As can be seen, this portion of the first wall 71 and the second wall 72 is located in the height portion H between the minimum level Qmin and the maximum level Qmax of the trench depth DG.

[0113] Preferably, the minimum level Qmin is greater than or equal to 10% of the trench depth DG.

[0114] Preferably, the minimum level Qmin is less than or equal to 30% of the trench depth DG.

[0115] More preferably, the minimum level Qmin is between 10% and 30% of the trench depth DG.

[0116] Preferably, the maximum level Qmax is greater than or equal to 40% of the trench depth DG.

[0117] Preferably, the maximum horizontal Qmax is less than or equal to 70% of the trench depth.

[0118] More preferably, the maximum level Qmax is between 40% and 70% of the trench depth DG.

[0119] Advantageously, such as Figures 2A-3B As can be seen, at least some of the plurality of protrusions 8 are disposed at corresponding heights at at least one of the first wall 71 and the second wall 72.

[0120] Advantageously, in another preferred embodiment, such as Figures 2A-3B As shown, at least some of the plurality of protrusions 8 are arranged along at least one line L that is substantially parallel to the tread surface 3.

[0121] Furthermore, referring to the aforementioned figures, the protrusions 8 are arranged along a plurality of additional lines LN that are substantially parallel to the tread surface 3.

[0122] Preferably, the multiple lines LN include two to four lines.

[0123] exist Figures 2A-3B In the example shown, there are two lines L1 and L2 with protrusion 8.

[0124] More preferably, as can be seen in the foregoing figures, the protrusions 8 arranged along the first line L1 are arranged in an alternating manner relative to the protrusions 8 arranged along another line L2 of the plurality of lines.

[0125] In a preferred embodiment, such as Figure 1 and Figures 2A-3A As can be seen only by example, the protrusions of the plurality of protrusions 8 are provided on both the first wall 71 and the second wall 72.

[0126] Alternatively, the plurality of protrusions 8 may be disposed on only one of the first wall and the second wall 71, 72.

[0127] Of course, those skilled in the art can make further modifications and variations to the tires of the present invention to meet specific and occasional application requirements, but such modifications and variations fall within the scope of protection defined by the following claims.

Claims

1. A tire (1) including a tread strip (2) located in a radially outer position, wherein a tread surface (3) is defined on the tread strip (2). The tread band (2) includes: - Multiple trenches (7A, 7B), each trench including a first wall (71) and a second wall (72) facing each other and defining the trench width (WG). In the plurality of grooves (7A, 7B), at least one of the first wall (71) and the second wall (72) of the transverse groove (7B) includes a plurality of protrusions (8) that protrude from the at least one of the first wall (71) and the second wall (72) by a protrusion width (WP). The protrusion width (WP) is less than 20% of the groove width (WG).

2. The tire (1) according to the preceding claim, characterized in that, The groove width (WG) is between 2 mm and 10 mm.

3. The tire (1) according to at least one of the preceding claims, characterized in that, The plurality of grooves (7A, 7B) have a corresponding base (9) located in a radially inward position between the first wall (71) and the second wall (72) and a corresponding groove depth (DG) from the tread surface (3) to the base (9).

4. The tire (1) according to the preceding claim, characterized in that, The plurality of protrusions (8) have corresponding protrusion heights (DP) in the radial direction, the protrusion heights being between 5% and 20% of the groove depth (DG).

5. The tire (1) according to claim 3, characterized in that, The plurality of protrusions (8) are disposed in a portion of at least one of the first wall (71) and the second wall (72), the portion having a height (H) between 20% and 50% of the trench depth (DG).

6. The tire (1) according to the preceding claim, characterized in that, A portion of at least one of the first wall (71) and the second wall (72) is positioned between a minimum height (Qmin) and a maximum height (Qmax), the minimum height being between 10% and 30% of the trench depth (DG) and the maximum height being between 40% and 70% of the trench depth (DG).

7. The tire (1) according to at least one of the preceding claims, characterized in that, At least some of the protrusions (8) are disposed at corresponding heights of at least one of the first wall (71) and the second wall (72).

8. The tire (1) according to at least one of the preceding claims, characterized in that, At least some of the protrusions (8) are arranged along at least one line (L) that is substantially parallel to the tread surface (3).

9. The tire (1) according to at least one of the preceding claims, characterized in that, At least some of the multiple protrusions (8) are arranged along multiple lines (LN) that are substantially parallel to the tread surface (3).

10. The tire (1) according to the preceding claim, characterized in that, The multiple lines (LN) include two to four lines.

11. The tire (1) according to at least one of claims 9-10, characterized in that, The protrusions arranged along the first line (L1) of the plurality of lines (LN) are staggered relative to the protrusions (8) arranged along another line (L2) of the plurality of lines (LN).

12. The tire (1) according to at least one of the preceding claims, characterized in that, Each of the plurality of protrusions (8) extends by a defined protrusion length (LP), and two protrusions of the plurality of protrusions (8) are spaced apart by a protrusion distance (PD).

13. The tire (1) according to the preceding claim, characterized in that, The protrusion distance (PD) is approximately equal to the protrusion length (LP).

14. The tire (1) according to at least one of claims 12-13, characterized in that, The protrusion length (LP) is between 0.5% and 10% of the groove length of the plurality of grooves (7A, 7B).

15. The tire (1) according to at least one of claims 12-14, characterized in that, The ratio of the protrusion length (LP) to the protrusion width (WP) is between 3 and 20.

16. The tire (1) according to at least one of claims 12-15, characterized in that, The ratio of the protrusion length (LP) to the protrusion height (DP) is between 5 and 10.

17. The tire (1) according to at least one of the preceding claims, characterized in that, Each of the plurality of grooves (7A, 7B) has a relative void volume, and the total protrusion volume of the plurality of protrusions (8) in each groove is between 0.5% and 8% of the void volume, preferably between 0.5% and 4% of the void volume.

18. The tire (1) according to at least one of the preceding claims, characterized in that, The protrusions (8) have an elongated shape, a hemispherical shape or an alternative elliptical shape or a basic polyhedral shape, preferably a basic cuboid shape.

19. The tire (1) according to at least one of the preceding claims, characterized in that, The protrusions (8) are disposed on both the first wall (71) and the second wall (72).

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