Crown Reinforcement For Airplane Tire
Aeroplane tire ( 1 ) comprises a working reinforcement ( 2 ) radially between tread ( 3 ) and carcass reinforcement ( 4 ). Working reinforcement ( 2 ) includes a working biply ( 21 ) comprised of the zigzag circumferential winding of strip ( 5 ) of width W onto a cylindrical laying surface ( 6 ) of radius R, with its axis of revolution being axis of rotation (YY′) of the tire, in a periodic curve ( 7 ) with period P and forming angle A with circumferential direction (XX′) of the tire in equatorial plane (XZ) of the tire. The winding of strip ( 5 ) comprises N periods P of curve ( 7 ) over T circumferences 2ΠR of surface ( 6 ). N is a whole number which satisfies the following conditions: (a) N*(W/sin A)=2ΠR, (b) N*P=2ΠR*T, where T is a whole number, (c) N*T is the lowest common multiple of N and T, and the ratio T/N is at least equal to 1.8 and at most equal to 2.2.
1 . A tire for an aeroplane, comprising:
a working reinforcement radially on the inside of a tread and radially on the outside of a carcass reinforcement;
the working reinforcement comprising at least one working biply comprised of two radially superposed working layers;
the at least one working biply comprised of a zigzag circumferential winding of a strip of width W onto a cylindrical laying surface of radius R, having as its axis of revolution the axis of rotation of the tire, in a periodic curve;
the periodic curve having a period P and forming an angle A with the circumferential direction of the tire in the equatorial plane of the tire;
the zigzag circumferential winding of the strip comprising N periods P of the periodic curve over a number T of circumferences 2ΠR of the cylindrical laying surface;
the number N of periods P of the periodic curve is a whole number which satisfies the following conditions:
(a) N*(W/sin A)=2ΠR,
(b) N*P=2ΠR*T, where T is a whole number,
(c) N*T is the lowest common multiple of N and T,
and the ratio T/N between the whole number T of circumferences 2ΠR of the cylindrical laying surface and the whole number N of periods P of the periodic curve which are needed to make up the at least one working biply, is at least equal to 1.8 and at most equal to 2.2.
2 . The aeroplane tire according to claim 1 , wherein the width W of the strip is at least equal to 2 mm.
3 . The aeroplane tire according to claim 1 , wherein the width W of the strip is at most equal to 20 mm.
4 . The aeroplane tire according to claim 1 , the strip being comprised of reinforcers coated in an elastomeric compound, wherein the strip comprises reinforcers made of a textile material.
5 . The aeroplane tire according to claim 1 , the strip being comprised of reinforcers coated in an elastomeric compound, wherein the strip comprises reinforcers made of an aromatic polyamide.
6 . The aeroplane tire according to claim 1 , the strip being made up of reinforcers coated in an elastomeric compound, wherein the strip comprises reinforcers made up of a combination of an aliphatic polyamide and of an aromatic polyamide.
7 . A method of manufacturing an aeroplane tire according to claim 1 , comprising a step of manufacturing the working biply, wherein the working biply is obtained by a zigzag circumferential winding of a strip of width W onto a cylindrical laying surface of radius R, having as its axis of revolution the axis of rotation of the tire, in a periodic curve, the periodic curve having a period P and forming an angle A with the circumferential direction of the tire in the equatorial plane of the tire, the zigzag circumferential winding of the strip comprising N periods P of the periodic curve over a number T of circumferences 2ΠR of the cylindrical laying surface, the number N of periods P of the periodic curve being a whole number which satisfies the following conditions:
(a) N*(W/sin A)=2ΠR,
(b) N*P=2ΠR*T, where T is a whole number,
(c) N*T is the lowest common multiple of N and T,
and the ratio T/N between the whole number T of circumferences 2ΠR of the cylindrical laying surface and the whole number N of periods P of the periodic curve which are needed to make up the working biply, being at least equal to 1.8 and at most equal to 2.2.
8 . The aeroplane tire according to claim 1 , wherein the width W of the strip is at least equal to 6 mm.
9 . The aeroplane tire according to claim 1 , wherein the width W of the strip is at most equal to 14 mm.
10 . The aeroplane tire according to claim 1 , the strip being comprised of reinforcers coated in an elastomeric compound, wherein the strip comprises reinforcers made of an aliphatic polyamide.