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CN-122029057-A - Tire for heavy vehicles with tread having improved wear resistance

CN122029057ACN 122029057 ACN122029057 ACN 122029057ACN-122029057-A

Abstract

The aim of the invention is to improve the resistance to irregular wear of a tire tread for a heavy vehicle, said tire tread comprising at least three compound incisions (31, 32, 33). According to the invention, the incisions are arranged opposite each other in a first direction (D1) such that a midpoint (I) of any external cavity (41) of the first incision (31) arranged between the second and third incisions (32, 33) is aligned with a respective midpoint (J, K) of the sipes (42) of the second and third incisions (32, 33) in a second direction (D2), and such that a midpoint (L) of any sipe (42) of the first incision (31) is aligned with a respective midpoint (M, N) of the external cavity (43) of the second and third incisions (32, 33) in the second direction (D2). Furthermore, the sipes (52) separating two adjacent blocks (51) are parallel to each other and distributed at a constant average pitch (Pi) along the first direction (D1).

Inventors

  • X. Loban
  • N. Herol
  • M. Krayevska
  • J. Breha

Assignees

  • 米其林集团总公司

Dates

Publication Date
20260512
Application Date
20241010
Priority Date
20231019

Claims (10)

  1. 1. A tyre (1) for heavy vehicles comprising a tread (2), said tread (2) being intended to be in contact with the ground by a tread surface (20), said tread (2) comprising at least three compound incisions (31, 32, 33) along a first direction (D1) tangential to the tread surface (20), At least when the tire is completely new, each compound incision (31, 32, 33) consists of an alternating arrangement of external cavities (41) opening onto the tread surface (20) and sipes (42) extending radially towards the inside of the tread (2) through internal cavities (43), two adjacent cavities, respectively external cavities (41) and internal cavities (43), communicating with each other, Two adjacent compound cuts (31, 32, 33) are separated by a row of blocks (51) which are adjacent to each other and separated by a knife channel (52) which opens at both ends into the outer cavities (41) of the two adjacent compound cuts, Characterized in that the at least three compound cuts (31, 32, 33) are equidistant from each other and are aligned opposite each other in a first direction (D1) such that a midpoint (I) of a longest dimension of any outer cavity (41) of a first compound cut (31) disposed between second and third compound cuts (32, 33) adjacent to the first compound cut (31) is aligned with a respective midpoint (J, K) of a sipe (42) of second and third compound cuts (32, 33) closest to the outer cavity (41) of the first compound cut (31) in a second direction (D2) and such that a midpoint (L) of any sipe (42) of a first compound cut (31) is aligned with a respective midpoint (M, N) of a respective longest dimension of an outer cavity (43) of second and third compound cuts (32, 33) closest to the sipe (42) of the first compound cut (31) and that two adjacent rows of sipe (51) are equally spaced apart from each other in a constant pitch (1) in a second direction (D2).
  2. 2. Tyre according to claim 1, wherein the first direction (D1) in which any compound incision (31, 32, 33) extends makes an angle with the circumferential direction (XX') at most equal to 70 °.
  3. 3. Tyre according to any one of claims 1 or 2, wherein the second direction (D2) makes an angle (B) with the first direction (D1) of at least 45 °.
  4. 4. A tyre according to any one of claims 1 to 3, the tread (2) having an axial width (W) measured in the direction (YY') between the first and second edges (21, 22) of the tread, and each outer cavity (41) of the compound cuts (31, 32, 33) having a shortest dimension, called width (Wcc), measured on the tread surface (20) between the two walls of the outer cavity (41), wherein the width (Wcc) of any outer cavity (41) is at least equal to 2% and at most equal to 7% of the axial width (W) of the tread (2).
  5. 5. Tyre according to any one of claims 1 to 4, each sipe (42) of a compound cut (31, 32, 33) having a minimum dimension called width (Wic) measured on the tread surface (20) between the two walls of said sipe (42), wherein the width (Wic) of any sipe (42) is at most equal to 2 millimeters.
  6. 6. Tyre according to any one of claims 1 to 5, each sipe (52) separating two adjacent blocks (51) in the same row of blocks having a shortest dimension called width (Wi) measured on the tread surface (20) between two walls of said sipe (52), wherein the width (Wi) of any sipe (52) is at most equal to 2 mm.
  7. 7. Tyre according to any one of claims 1 to 6, wherein the first direction (D1) in which any compound cut (31, 32, 33) extends is circumferential.
  8. 8. Tyre according to claim 7, the tread (2) having an axial width (W) measured in the axial direction (YY ') between the first and second edges (21, 22) of the tread, wherein the at least three circumferential compound cuts (31, 32, 33) are distributed in the axial direction (YY') with a constant average axial pitch (Pd) at least equal to 10% and at most equal to 25% of the axial width (W) of the tread (2).
  9. 9. Tyre according to any one of claims 7 or 8, the tread (2) having a circumferential length measured in a circumferential direction (XX') at the centre of the tread surface (20), wherein a constant average circumferential pitch (Pi) between two adjacent sipes (52) is at least equal to 0.5% and at most equal to 2% of the circumferential length of the tread (2).
  10. 10. Tyre according to any one of claims 7 to 9, wherein the tread (2) comprises at least four, preferably five compound incisions (31, 32, 33).

Description

Tire for heavy vehicles with tread having improved wear resistance Technical Field The present invention relates to a tyre for heavy vehicles intended to run on bituminous surfaces, and more particularly to the tread of said tyre. Background The tread is located at the periphery of the tire and is intended to wear upon contact with the ground via the tread surface, and is made of at least one rubber-based material. The tread generally comprises a tread pattern, which is a combination of incisions or voids and raised elements, which is specifically intended to ensure satisfactory performance in terms of grip, more specifically on wet roads. It is known that wet weather driving conditions of vehicles, more particularly heavy vehicles, require a rapid evacuation of the water present in the ground-contact surface between the tread of the tyre and the road surface. This way of draining makes it possible to ensure that the material constituting the tread is in direct contact with the road surface through the tread surface. Water that is not pushed toward the front or side of the tire then flows into or partially accumulates in the incisions formed in the tread. The evacuation of the water is ensured by the cuts, which form a fluid flow network, which preferably must be permanent, i.e. effective over the entire service life of the tyre from a completely new state to a state of maximum wear. The state of maximum wear is specified by current regulations, beyond which the tyre must be removed from the vehicle for safety reasons. Tires for heavy vehicles typically have a usable void volume on the ground contact surface that is relatively large in the new tire condition. The usable void volume is understood to mean a void volume which can be filled by water present on the road surface. The void volume leading to the tread surface is assessed when the tire is subjected to recommended inflation and loading conditions, in particular defined by the European tire and rim technical Organization (European TYRE AND RIM TECHNICAL Organization or ETRTO) under its "Standard handbook 2022-commercial vehicle tire". Among these cuts, the sipe and the groove are distinguished. The sipe has a width such that, when the tread enters the ground-contacting surface, under the tire load and pressure conditions specified by ETRTO, the opposing walls of material defining the sipe at least partially contact one another, thereby limiting deformation of the opposing portions of material and thereby reducing wear. In contrast, the grooves are wider than the sipes, and they define portions of material that are able to deform as the tread enters the ground-contacting surface but do not contact each other. Deformation of these material portions under compression and shear results in increased wear of the tread. Further, when grooves are present, an increase in deformation causes an increase in hysteresis loss of the tread, thereby increasing rolling resistance, with the result that fuel consumption increases. In order to limit the reduction of the tread material volume caused by the presence of grooves, so-called compound cuts are proposed which allow to increase the tread material volume while meeting the water void volume requirement above a certain threshold, regardless of the degree of wear of the tire, compared to a normal cut which leads entirely to the tread surface. Treads comprising such compound incisions have been described in particular in documents WO 2011039194 A1, WO 201101495 A1, WO 2012130735 A1, WO 2020030667 A1 and WO2020058622 A1. When a new tire is used, the compound cuts open onto the tread surface in a discontinuous manner, at regular or irregular intervals. Each compound cut has external cavities opening onto the tread surface, which are separated from each other in the main direction of the compound cut. The main direction of the composite cut corresponds to the direction of water flow in said cut when driving on a water-bearing ground. In addition to the outer cavities, the compound cut also includes inner cavities formed in the tread interior, which are typically connected to the tread surface by sipes. When a new tyre is used, these internal cavities are located radially completely inside the tread surface and are interposed between the external cavities. The internal cavities may be located at different depth levels of tread thickness. Furthermore, by the connection between the outer and inner cavities respectively, the flow continuity of the water (or more generally fluid) in each composite incision at the time of the new tyre is ensured. The connection between the inner and outer cavities thus forms a continuous channel, irrespective of the local orientation of the inner or outer cavity. In contrast, if the juxtaposed inner and outer cavities are not connected to each other, and thus do not allow fluid to flow from one cavity to the other around the entire circumference of the tire, a continuous channel is not formed.