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CN-122029055-A - Tire with advantageous balance of performance between snow grip and rolling resistance

CN122029055ACN 122029055 ACN122029055 ACN 122029055ACN-122029055-A

Abstract

The invention relates to a tyre (1), the tread (10) of said tyre (1) comprising tread pattern elements distributed at a distributed pitch along the rim of the wheel. Each tread pattern element comprises at least one central block (140) provided with blocking elements (220). The blocking element (220) has a blocking face (270) having a surface area Sb and opposing the face of the central tread block (140), the face of the central tread block (140) being referred to as the free face (250) and having a surface area Sf. The tire (1) is characterized in that for at least one central tread block (140), the ratio Sb/Sf is between 0.25 and 0.85, that at least one first central tread block (140) on a first side of the equatorial plane (C) comprises a first blocking element (220) opposite a second blocking element (220) of a second central tread block (140) on a second side of the equatorial plane (C), that the first central tread block (140) comprises a blocking element (220) flush with the central groove (100) over a width L1, and that the second central tread block (140) comprises a further blocking element (220) flush with the central groove (100) over a width L2.

Inventors

  • C. Olambot
  • N. Herol

Assignees

  • 米其林集团总公司

Dates

Publication Date
20260512
Application Date
20241018
Priority Date
20231026

Claims (12)

  1. 1. A tyre (1) having a tread (10) intended to be in contact with the ground by a tread surface (20): -the tread (10) comprises raised elements arranged at least into first and second tread pattern elements (MA, MB), at least partly separated from each other by grooves (30), and extending radially outwards from the bottom surface (40) up to the tread surface (20) by a radial height H at least equal to 6 millimeters and at most equal to a radial thickness H sre of the tread (10); -each tread pattern element (MA, MB) comprises a tread pattern half-element (MA 1, MB 1), said tread pattern half-element (MA 1, MB 1) being arranged on a first side of an equatorial plane (C) passing through the centre of the tread (10) and then continuing on a second side of said equatorial plane (C), forming a further half-element (MA 2, MB 2); -forming a tread pattern by repeating said tread pattern elements (MA, MB) at respective pitches (PA, PB) on the rim of the wheel, wherein PA < PB; -each tread half-element (MA 1, MA2; MB1, MB 2) comprises a tread block (135) extending from the axial end of the tread (24G, 24D) edge up to the centre of the tread (10), so as to form a groove (100) centred on the equatorial plane (C), the tread blocks of the innermost tread half-elements being called central tread blocks (140); -at least one central tread block (140) comprises at least one blocking element (220) constituted by a protrusion adjacent to a face (250), called free face, of the central tread block (140) and extending up to be flush with the central groove (100); -the blocking element (220) has at least one face called blocking face (270), said blocking face having a surface area Sb, the free face (250) having a surface area Sf; The tire (1) is characterized in that for at least one central tread block (140), the ratio Sb/Sf is between 0.25 and 0.85, that at least one first central tread block (140) on a first side of the equatorial plane (C) comprises a first blocking element (220) opposite a second blocking element (220) of a second central tread block (140) on a second side of the equatorial plane (C), that the first central tread block (140) comprises a blocking element (220) flush with the central groove (100) over a width L1, and that the second central tread block (140) comprises a further blocking element (220) flush with the central groove (100) over a width L2.
  2. 2. Tyre (1) according to claim 1, wherein the distance Dbloc is between 0.1 and 2 millimeters, said distance Dbloc being the distance between the blocking face (270) of the first blocking element (220) of the first central block (140) and a further blocking face (270) of the second blocking element (220) of the second central block (140), said further blocking face being arranged opposite the first blocking face with respect to the equatorial plane (C).
  3. 3. Tyre (1) according to any one of claims 1 and 2, wherein the widths (L1, L2) are proportional to the width of the first and second central blocks, respectively, measured along the central groove.
  4. 4. A tyre (1) according to any one of claims 1 to 3, wherein the blocking surface (270) of the blocking element (220) has undulations oriented along the central groove (100) and/or in a radial direction perpendicular to the rotation axis of the tyre (1).
  5. 5. Tyre (1) according to any one of claims 2 to 4, wherein the distance Dbloc between two blocking surfaces (270) disposed opposite each other with respect to the equatorial plane varies in the radial direction and reaches a maximum at the radially inner end of the blocking surface (270).
  6. 6. Tyre (1) according to any one of claims 1 to 5, wherein a passage is provided at the radially inner ends of the first and second blocking elements (220) opposite each other with respect to the equatorial plane (C) leading to the central groove (100).
  7. 7. Tyre (1) according to any one of claims 1 to 6, the ground contact surface being the surface formed on the ground by compression when the tyre is running, the angle γ being the angle formed by the edge corner of the barrier surface (270) which first enters the ground contact surface in the running direction (150) of the tyre (1) and the radial direction, wherein said angle γ is between 0 ° and 10 °.
  8. 8. Tyre (1) according to claim 7, wherein the angle δ formed by the edge corner of the blocking surface (270) next to the ground-contacting surface and the radial direction along the running direction (150) of the tyre (1) is greater than the angle formed by the edge corner of the free surface (250) next to the ground-contacting surface and the radial direction.
  9. 9. Tyre (1) according to claim 8, wherein the angle δ is greater than 30 °.
  10. 10. Tyre (1) according to any one of claims 1 to 9, wherein the central groove (100) forms an average angle with the circumferential direction of between 30 ° and 55 °.
  11. 11. Tyre (1) according to any one of claims 1 to 10, wherein each tread block (135) comprises one or more sipes (160), the sipes (160) being incisions in the tread surface (20), wherein the distance between the walls of material delimiting the sipes (160) is less than or equal to 2mm and the depth is greater than or equal to 1 mm.
  12. 12. Tyre (1) according to any one of claims 1 to 11, wherein the radially external surface of the blocking element (220) is at a distance from the tread surface (20) of greater than or equal to 2 millimeters, said distance being the maximum value of the radial projection of the points on the radially external surface of the blocking element (220) on the tread surface.

Description

Tire with advantageous balance of performance between snow grip and rolling resistance Technical Field The present invention relates to a tyre for motor vehicles, and more particularly to a "full season" tyre optimized in terms of rolling resistance and intended to be mounted to a passenger vehicle or truck. Background It is known that so-called "all season" tires for passenger vehicles or trucks exhibit a compromise between grip on snow covered ground and grip on wet ground while maintaining performance on dry ground. These tires are intended to run safely throughout the year regardless of weather while exhibiting improved performance in terms of rolling resistance compared to conventional designs. In terms of their performance on snowy floors, these tires have generally obtained a prescribed winter certification 3PMSF (trimodal snow flakes) which, according to regulations concerning the safety of the tire, such as UNECE (United Nations Organization for the European Economic Committee, the united nations european economic committee) regulations R30/R54 and R117, proves to have a certified grip performance on snowy floors and on wet floors. The certification is indicated on one or both sidewalls of such tires by a unique trimodal snowflake (3 PMSF) mark. The invention also relates to a multipurpose tyre which can be used under different weather conditions, marked on at least one of its sidewalls with "m+s" (mud+snow). The term "grip" is understood to mean both the grip characteristics of the tire in the transverse direction with respect to the movement of the vehicle (for example over-bending performance) and the grip characteristics of the tire in the longitudinal direction with respect to the movement of the vehicle, i.e. the possibility of transmitting braking or driving forces to the ground. Definition of the definition Hereinafter, the circumferential, axial and radial directions refer to a direction tangential to any circle centered on the rotation axis of the tire, a direction parallel to the rotation axis of the tire and a direction perpendicular to the rotation axis of the tire, respectively. Conventionally, in a reference frame (O, XX ', YY', ZZ ') in which the center O coincides with the center of the tire, the circumferential direction XX', the axial direction YY ', and the radial direction ZZ' refer to a direction tangential to the tread surface of the tire in the rotation direction, a direction parallel to the rotation axis of the tire, and a direction orthogonal to the rotation axis of the tire, respectively. "Radially inner/radially inner" and "radially outer/radially outer" refer to "closer to the axis of rotation of the tire" and "farther from the axis of rotation of the tire", respectively. "Axially inner/axially inner" and "axially outer/axially outer" refer to "closer to the equatorial plane of the tire" and "further from the equatorial plane of the tire", respectively, which are planes passing through the middle of the tread of the tire and perpendicular to the axis of rotation of the tire. Typically, the circumferential plane is a plane perpendicular to the axis of rotation of the tire. The tire comprises a crown intended to be in contact with the ground via a tread, the two axial ends of which are connected via two sidewalls to two beads that provide a mechanical connection between the tire and a rim on which the tire is intended to be mounted. "Tread surface" of a tread refers to the surface of a tire that combines all points of contact with the ground under normal running conditions. These points of contact with the ground belong to the contact surface of the block. For tires, "normal running conditions" are conditions of use defined by ETRTO (european tire and rim technical organization) standards. These conditions of use define a reference inflation pressure corresponding to the load carrying capacity of the tire (as indicated by the tire load index and speed ratings). These conditions of use may also be referred to as "nominal conditions" or "operating conditions". The total width of the tread is the axial distance between the axial ends of the tread surface, which are distributed on both sides of the equatorial plane of the tyre. From a practical point of view, the axial ends of the tread surface do not necessarily correspond to well-defined points. It should be remembered that the tread outer portion is delimited on the one hand by the tread surface and on the other hand by two connecting surfaces of the tread intersecting two sidewalls connecting said tread to two beads intended to provide a connection with the mounting rim, so that the axial end can be defined mathematically as the orthogonal projection on the tread of the theoretical intersection point between the tangent to the tread surface in the axial end region of the tread surface and the tangent to the connecting surface in the radially outer end region of the connecting surface. The overall width of the tread substa