Tire For a Civil Engineering Vehicle, Comprising a Level-Wound Crown Reinforcement with Metal Reinforcements

Patent metadata

Field	Value
Publication number	US-2022016934-A1
Application number	US-201917299642-A
Country	US
Kind code	A1
Filing date	Dec 2, 2019
Priority date	Dec 5, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

Reinforcers of crown layers (211, 212) of a civil engineering vehicle are made of metal and wound, in the form of a strip (5) of width W, along a circumferential zigzag trajectory following a periodic curve (7), extending over a number N of periods P distributed over a number T of circumferences 2ΠR and satisfying the two relations N*(W/sin A)=2ΠR*t, where 0.6⇐t⇐1, and N*P=2ΠR*T, so as to form a bilayer (21). Additionally, for at least 40% of the strip crossovers (53) axially positioned, relative to the circumferential direction (XX′), at an axial distance L1 equal to not more than 0.25 times the amplitude L of the periodic curve (7), the circular bilayer portion (213), centred on the strip crossover (53) and having a radius R1 equal to twice the width W of a strip (5), comprises Ne outer strip crossovers and Ni inner strip crossovers, such that |Ne-Ni|/(Ne+Ni)⇐0.3.

First claim

1 . A tire for a civil engineering vehicle, comprising:
a crown reinforcement radially on the inside of a tread and radially on the outside of a carcass reinforcement; the crown reinforcement comprising at least a crown bilayer made up at least partially of two radially superimposed crown layers, each made up of reinforcers coated in an elastomeric material; each crown bilayer being made up of a circumferential zigzag winding of a strip of width W, in a circumferential direction (XX′) of the tire and on a substantially cylindrical surface of revolution positioned at a radial distance R from the axis of rotation (YY′) of the tire; the trajectory of the circumferential zigzag winding being a periodic curve having a period P and an amplitude L; the periodic curve forming, with the circumferential direction (XX′), an angle A measured at the points on the curve positioned in an equatorial plane (XZ) passing through the centre of the tread and perpendicular to the axis of rotation (YY′), the periodic curve extending over a number N of periods P distributed over a number T of circumferences 2ΠR; the trajectory of the circumferential zigzag winding generating strip crossovers between a radially outer portion of strip and a radially inner portion of strip; a strip crossover being outer when the radially outer portion of strip forms a positive angle B with the circumferential direction (XX′) in an axial plane (XY); a strip crossover being inner when the radially outer portion of strip forms a negative angle B with the circumferential direction (XX′) in an axial plane (XY); wherein the crown layer reinforcers are made of metal, the periodic curve of the trajectory of the circumferential zigzag winding satisfies the following relations:
N *( W /sin A )=2 ΠR*t , where 0.6⇐ t⇐ 1,

N*P= 2 ΠR*T,
and for at least 40% of the strip crossovers axially positioned, relative to the circumferential direction (XX′), at an axial distance L 1 equal to not more than 0.25 times the amplitude L of the periodic curve, the circular bilayer portion centred on the strip crossover and having a radius R 1 equal to twice the width W of a strip comprises Ne outer strip crossovers and Ni inner strip crossovers, such that |Ne-Ni|/(Ne+Ni)⇐0.3.

2 . The tire according to claim 1 , wherein any metal reinforcer has a circular cross section of diameter D, and wherein the width W of the strip is at least equal to D.

3 . The tire according to claim 1 , wherein the width W of the strip is equal to not more than 0.2 times the amplitude L of the periodic curve.

4 . The tire according to claim 1 , wherein the periodic curve has extrema and a radius of curvature R′ at its extrema, and wherein the radius of curvature R′ of the periodic curve is at least equal to the amplitude L of the periodic curve.

5 . The tire according to claim 1 , wherein the periodic curve has extrema and has a radius of curvature R′ at its extrema, and wherein the radius of curvature R′ of the periodic curve is at least equal to 7 times the amplitude L of the periodic curve.

6 . The tire according to claim 1 , wherein the ratio T/N is at least equal to 0.15 and at most equal to 1.3.

7 . The tire according to claim 1 , wherein N and T are whole numbers that are prime between each other.

8 . The tire according to claim 1 , wherein the metal reinforcers of the crown layers are elastic metal reinforcers having a structural elongation As at least equal to 0.5% and a tensile modulus of elasticity of not more than 150 GPa.

9 . The tire according to claim 8 , wherein the elastic metal reinforcers of the strip are multistrand ropes of structure 1×I comprising a single layer of I strands wound in a helix, each strand comprising an internal layer of J internal threads wound in a helix and an external layer of K external threads wound in a helix around the internal layer.

10 . The tire according to claim 1 , wherein the crown reinforcement comprises at least two crown bilayers.

Assignees

• Michelin & Cie

Inventors

• Barbarin François

Classifications

• B60C9/263 Primary

  further characterised by an endless zigzag configuration in at least one belt ply, i.e. no cut edge being present · CPC title

• B60C9/2006

  consisting of steel cord plies only · CPC title

• B60C9/20

  built-up from rubberised plies each having all cords arranged substantially parallel · CPC title

• B60C2200/065

  for construction vehicles · CPC title

• B60C9/26

  Folded plies · CPC title