FR2608515A1 - REINFORCING BELT REINFORCING BELT FOR HIGH PERFORMANCE PNEUMATIC TIRES - Google Patents

Abstract

THIS TIRE FEATURES A TOROIDAL CARCASE 1 IN THE FORM OF RADIAL CABLE BALLS AND A BELT 2 FOR REINFORCING THE TREAD 7, CONSTITUTED BY SUPERIMPOSED CABLES PARALLELED TO ONE TO THE OTHERS AND INCLUDING A FIRST GROUP (A) OF SEVERAL CABLES AT THE EQUATORIAL PLANE OF THE TIRE AND A SECOND GROUP (B) OF INCLINED CABLE LAYERS IN RELATION TO THE EQUATORIAL PLANE AND AT LEAST ONE OF THE BELT LAYERS OF THE GROUP (A) HAS A WIDTH GREATER THAN 1.1 TIMES THE WIDTH W OF GROUND CONTACT OF TREAD 7 UNDER NORMAL OPERATING CONDITIONS OF THE TIRE, AND THE LAYERS OF GROUP (B) HAVE EACH DIFFERENT TILT FROM THE LAYERS OF THIS GROUP WHICH ARE NEIGHBORED AND HAVE A WIDTH NOT EXCEEDING THEM. WIDTH W. APPLICATION ESPECIALLY TO AIRCRAFT TIRES.

Description

The present invention relates to a pneumatic tire

  high performance or for severe service conditions.

  and more particularly relates to a tire of the type des-

  designed to be used for aircraft ground running. Here, we discuss the results concerning research into

  development aiming at achieving both durability and

  ting and stability during cornering in the case of

  high speed, and in particular with regard to the improvement

  the service life in relation to the reinforcement

the reinforcement belt.

  In the case of radial-ply tires, a tread portion is reinforced by a plurality of waist layers, in which ropes

  or wired are crossed. When using such tires

  As aircraft tires, it is possible that it appears what are called stationary waves.

  during high-speed rolling, because of a resistance

  insufficient tension of the belt to traction the lcng of the circumference of the tread, to the neighboragee

  the part constituting the shoulder of the tire. It's for-

  what is the risk that the durability of the tires

is greatly reduced.

  In connection with the problems indicated above, published Japanese patent applications Nos. 201 701/82 and 201 702/82 indicate that a material constituting

  strings or cords having, in the lateral areas of the necks

  belt, in the radial section, an extensibility

  greater than in the central zone of the latter, in the belt layers constituted by cords which are arranged by being inclined at an angle no greater than

    relative to the circumference of the

  of rolling stock, and such a carcass coating is used so as to favor to a large extent the increase in

  shoulder portions when internal pressure is

  re is applied to the tire, while the request for

2 6 0 8 5 1 5

  Japanese Patent Publication No. 201 704/82 indicates that a new tire having a plurality of belt layers constituted by circumferential cords having a

  certain extensibility and some ownership of contrac-

  thermal effect due to the heating effect, is vulcanized in a mold having the shape of the letter U, flaring out

  outward in the radial direction. Even though

  seems from the documents cited above can guarantee

  durability in the case of a large-scale operation

  aircraft take-off and landing, an undesirable reduction in cornering resistance is associated This is why there is a problem

  in that cornering stability during take-offs, that is

  ie at the time of rolling on the ground, is reduced.

  That is why an object of the present invention is

  to provide a reinforcing structure for the formal part

  tread, which avoids

  the appearance of standing waves in a pneumatic tire.

  high-performance radial carcass tick, when

  at a high speed, without being associated with

  a reduction in cornering resistance.

  Another object of the present invention is to provide

  a radial tire particularly suitable for

  The invention is particularly useful for airplanes having a reinforcing belt, the structure of which combines a belt layer of circumferential cords and a belt layer formed of oblique cords, and has a satisfactory cable-peel strength and a satisfactory strength at one end.

uneven wear.

  The first objective mentioned above of the pre-

  invention is effectively achieved through the reali-

indicated below.

  Indeed the high performance tire

  form of the invention comprises, as main reinforcing element, at least one toroidal carcass constituted by

  a ply of radially extending cords which are

  placed in parallel at an angle between 90 and with respect to an equatorial plane of the tire, andby a

  belt for reinforcing the tire tread

  tick, consisting of superimposed cords in an area

  constituting the crown or crown of the carcase and

  placed parallel to each other in order to reinforce the tread portion, and said belt is constituted by a first group formed

  several layers consisting of cords arranged essentially

  parallel to the equatorial plane of the tire and

  by a second group of several layers consisting of

  of at least one of the belt layers belonging to the first group has a predicted width which is greater than 1.1 times the contact width at the same time. ground of the tread portion under normal internal pressure conditions

  and normal load of the tire, and the

  belonging to the second group possessed

  different clinching relative to the adjacent layers of the same second group and are each interposed between any combination of the carcass ply,

  belt layers belonging to the first group and from

  belt layers belonging to the second group and have a width not exceeding the contact width of the tread

  the conditions of normal internal pressure and normal

  of the tire, nor the expected width of the

  belonging to the first group and which are the most

  next to the sides which are located radially furthest

  inner and outermost.

  According to a preferred embodiment of the present invention,

  invention, the belt and / or the carcass is

  killed by cords made of organic fibers.

  In accordance with a second aim of the present invention,

  A high performance tire is provided in which the gap between the cords constituting the circumferential cordslayer is at least on the outermost side in the radial direction and set at the level of the zones. opposite sides,

  a higher value than in the central area of the

che belt.

  Other features and advantages of the pre-

  invention will emerge from the description given below.

  after making reference to the accompanying drawings, for which

  it will be understood that some modifications or changes may

  can easily be provided by the specialist in

  that to the invention, without scrtir the frame of the latter, and in which: - Figure 1 is a sectional view showing a high performance tire according to the present invention; FIG. 2 represents sectional views showing

  main parts of the tire conforming to the present

  the invention; and FIG. 3 represents a schematic partial sectional view showing the arrangement of a belt of a radial tire for an airplane, in accordance with FIG.

  another embodiment of the present invention.

  Hereinafter, the present invention will be explained.

  in more detail with reference to the

  secured. FIG. 1 shows a sectional view of an embodiment of a tire in accordance with FIG.

  present invention and FIGS. 2 (a), (b) and (c) represent

  try different modifications of the structure

of the belt.

  In FIG. 1, the reference numerals 1 and 2 relate to a carcass using two radial mats a

  and b respectively constituted by cords formed of

  and 3 and 4 and 5 and 6 respectively denote a bead, a bead and reinforcement members consisting of hard rubber and soft rubber. The carcass 1 may be formed by a sheet consisting of cords formed of metal son,

especially steel.

  The belt 2 is constituted by cords formed of fibers preferably organic, superimposed around a

  the top portion of the carcass 1 and arranged in parallel

  1), and is subdivided into a first group m including several layers (belt layers formed by circumferential cords) comprising cords arranged substantially parallel to the equatorial plane of pneumatic and a second group 5 (belt layers formed of oblique cords) comprising cords which are inclined at an angle of between 15 'and 65 with respect to

equatorial plane of the tire.

  At least one of the belt layers belonging to the first group c and having a width greater than 1.1 times to the ground contact width W of the band portion

  7, under the conditions of normal internal pressure

  male and normal load of the tire.

  The belt layers belonging to the second group

  they are belt layers made of

  different from belt layers formed from

  neighboring countries by the fact that they are

  oblique direction, and are interposed between any combination involving the carcass ply, the belt layers belonging to the first

  group x, and other belt layers belonging to the

  cond group j3. The waist layers belonging to the se-

  group have a width not exceeding

  ground contactor W of the roll forming part

  under the conditions of normal internal pressure and normal load of the tire, nor to the expected width of the belt layers belonging to the first group y, which are the nearest to the innermost sides and the

  outside on the radial directions of the tire-

  matic. In what follows, the second aspect of the invention will be explained in more detail with reference to

  Figure 3. The embodiment shown in the figure

  FIG. 3 relates to the present invention applied to a pneumatic tire.

  O10 plane radial carcass tick having dimensions H 46 x 18.0 R 20. Figure 3 is a partial sectional view

  schematic showing the structure and layout of the structure

  the belt of this tire.

  The tire conforms to this form of

  comprises two carcass plies 11 and 12 constituted by cords arranged perpendicular to the circumferential direction of the tire, four belt layers

  circumferences 21, 22, 23 and 24 constituted by cables

  parallel to the circumferential direction, and inclined belt layers 31 and 32 inclined by

  relative to the circumferential direction of the tire.

  The belt layers 21, 22, 23 and 24 formed by circumferential cables, are constituted by formed cables. of aromatic polyamide fibers of size 3000 d / 3, which are each subdivided into a central zone Cw having a width equal to about 85% of the ground contact width Tw of the tread 7 under load

  and in the remaining opposite side zones. It's for-

  the opposite lateral zones comprise zones LW, LW 'arranged in the axial direction, respectively

  inside and outside the ground contact edges P.

  The gap between the adjacent cords constituting the circumferential cords of belt layers is del, 4 mm in the central zone and 2.4 mm in the opposite lateral zones. The hardness of the rubber coating covering the cords in the circumferential cords of belt layers has a Shore A hardness of 75 in the

  central area and 60 in the opposite side areas.

  On the other hand, the belt layers 31 and 32 form

  oblique cords consist of cords formed of aromatic polyamide fibers of a size of 3000 d / 3 as in the case of belt layers formed of cords.

  circumferential circumferences, and the uXoles of the

  oblique cords are inclined 65 with respect to the circumferential direction. The belt layers 31 and 32 formed of oblique cords are arranged such that the directions of their cords are reciprocally reversed. These belt layers 31 and 32 formed of oblique cords are arranged respectively between the first and second belt layers 21 and 22 formed of cords.

  oblique and between the second and third layers of

  22 and 23 formed of circumferential cords, as visible from the inside, in the radial direction. The width of the belt layers 31 and 32 formed of oblique cords is equal to about 95% of the width

ground contact TW.

  In accordance with the first aspect of this

  vention, at least one of the belt layers belonging to

  the first group "is arranged so as to extend

  that the buttress shoulder portion of such

  that the planned width is not less than 1.1 times the

  contact width on the ground of the roll forming part

  under the conditions of normal internal pressure and normal As a result, it is possible to obtain sufficient circumferential tensile strength at the shoulder portion and at the

  buttressing part. This favors the rapid deletion

  bending deformation as well as the damping of the vibrations due to the load, close to the area, which

  is subjected to tension, of the web-forming part

2 6 0 8 5 1 5

  in the case of high speed rolling, so that delaying action can be

  stationary, which largely contributes to improving the

  calf durability of the belt portion.

  In addition, the presence of oblique cord shaped belt layers in the second group improves in a more consistent way the resistance to lateral deformation produced in the axial direction.

  rotation shaft of the tire, in the con-

  in the loaded state, in relation to the structure con-

  staggered by stacking only the belt layers

  part of the first group. In particular, in order to

  To increase this effect, it is necessary to limit the angle of the belt layers formed of oblique cords to a range

  values between 15 and 65 '.

  The following table 1 indicates values of the

  cornering resistance when using the structure of cou-

  Belt belts shown in Figure 1 and that the angle of the belt layers formed oblique cords. The directions along which the oblique cords are disposed in the belt layers belonging to the second group are inverted alternately. The value is indicated as an index and the value of the cornering resistance of a cross-carcass tire of

  same dimensions is taken equal to 100.

Table 1

  Angle of inclination of cords (in degrees)

  30 50 | 650 95

  Resistance en | | turn | 50 80 100 90 80 60

  The resistance can be further improved by

  compared to the values given in Table 1 in

  increasing the number of belt layers formed by

oblique wheats.

  In general, in the case of diapers

  oblique cords or an infra-

  formed of oblique cord and belt layer belt layers formed of circumferential cords

  irrespective of any combination, the distortion

  circumferential inter-layer shearing occurs between the belt layers in the vicinity of

  parts of them, in the loaded state, which is a

  main problems with the side parts

  of the belt, during the ride.

  Therefore, the predicted width of the oblique cordbelt layers should be set to a value no greater than the base contact width W1 of the tread portion 7 under normal internal pressure and normal load conditions. , when

  the durability of the lateral parts is taken into account.

  belt. This provision is intended to re-

  essentially the appearance of a deformation

  at the side portions of the belt, while avoiding a position between the ground contact edge and the reinforcing portion, which is being lengthened

  maximum circumferential circumference in a radially

  of the flexion occurring when the part forming

  ture bends under the action of the load.

  In addition, the complete coating over the entire

  belt layers formed of oblique cords by circumferential cords of circumferential cords,

  which are closest to the sides, the most

  outside and radially outwards,

  belt layers is necessary to effectively limit

  ficaces the circumferential displacement of the edges of each

  belt layers, during deformation under load.

  If the intended width of the belt layer formed by

  oblique wheats exceed circumferentially circumferential cords, which are radially inward or outwardly located and sandwich the belt layer of oblique cords, it has been found that the circumferential

  marginals of the belt layer formed of

  This is because the inter-layer shear stress becomes larger and tends to cause separation at the marginal portions of the belt layer formed by oblique cords at the beginning of rolling, causing disturbances. On the other hand the marginal parts of the belt layer formed of oblique cords, which is completely

  placed between the belt layers made of

  circumferential over the entire width can fully guarantee a sustainable level

  the lateral deformation of the belt, which occurs

  the axial direction of the axis of rotation of the tire.

  in the area of ground contact during rolling, without causing separation or separation of the cords. In addition, resistance to a lateral force produced in the direction of the axis of rotation of the tire in the ground contact zone results in an effect of increasing the apparent circumferential rigidity of the edges of the tire layer. belt made of oblique cords, which increases cornering resistance and improves cornering stability

  vis-à-vis any excessive lateral force.

  In order to fully obtain the effects due to

  provision according to which the interval

  the neighboring cords of the belt layer formed by circumferential cords, a different value in the

  central and in the opposite lateral zones, it is desirable

  table that the opposite side zones extend towards the

  from the ground contact edges of the tread, in the axial direction, and includes

  tread extending over a width not greater than

  than 30% of the tread width.

  In addition, in order to reduce in a more efficient way

  the shearing force appearing at the level of

  terfaces between the strings when a compressive force is applied to the opposite side

  belt made of circumferential cords, according to the

  axial rection, it is advantageous, for the practical implementation of the present invention, to cover the cords at opposite side zones, with ur coating

  made of rubber having a hardness lower than that of

  rubber garment of the cords in the central zone, and preferably having a Shore A hardness of between

  about 70% and 85% of the hardness of said rubber coating

  Chouc. Hereinafter, the present invention will be explained in more detail with reference to examples, which should not be construed in any way as limiting the object of the invention, but are merely given by way of example.

illustration of this last.

  In Figure 1 there is shown an arrangement of a belt member used in an aircraft tire, having dimensions 40 x 14-16. The tire comprises two carcass plies, the two lateral parts of which are

  wrapped around a pair of rods 3 provided respecti-

  on the right side and on the left side. Many

  belt layers are arranged in a roll of

  tire. Wires of aromatic polyamide

  than a size of 3000 d / 3 are used in the water table

  radial carcass and in the belt layer. The pneumatic

  that corresponding to these dimensions has a contact surface, the width of which is equal to 280 mm, on a flat road surface, in the case of a load of 1280 kg and in the case of an internal load pressure of 1173.103 Pa. On

  has prepared, on a trial basis, a tire with a

  axial axis as specified in Table 2 below, along the periphery of the belt, and in which

  the angle of the first, third and fifth layers of

  ture equals 0 (circumferential direction), and the

  second and fourth layers are equal respectively

  at + 65 and - 65 in Figure 1.

  The ratio of the maximum width of the belt formed by circumferential cords of the tires n, b

  and c to the ground contact width as mentioned above.

  above is equal to 1.25, 1.10 and 0.93, respectively. In the conditions of load and internal pressure mentioned

  above, the running speed of the tire has been increased.

  The rate at which stationary waves appeared was compared by means of an index, and the results were

  reproduced in the right-hand column of Table 2.

Table 2

  Cein-Cein-Cein-Cein- Cein- Rate of occurrence tureure ture 2 ture 3 ture 4 ture 5 stationary wave (, | r) (nm) (.n) (rm) (rnn) (index) a) 350 200 260 240 245 116 b) 310 200 260 240 245 100 c) 260 200 260 240 245 71 In this comparison, the value for stationary wave velocity was taken from the conventional cross-structure tire having the same dimensions. During a durability test performed

  at high speed during which an accelerated

* ration starting from the state of rest until a speed of de-

  specified, as constituting a cycle, the tire

  C has exhibited a delamination fault at the tread portion after repeated tests

  for several cycles. It turned out that the pneumatic

  a and b had satisfactory sustainability without

  disturbed during the test referred to above.

  above, as well as during the test under high load. To confirm the functions and effects provided by the embodiment of the present invention as

  shown in Figure 3, experiments have been carried out

  these comparatives using the following three tires.

  1. A comparative tire, in which the

  between the cords and the hardness of the rubber coating.

  The circumferential cords of the belt layer did not vary between the opposite lateral zones and the central one. In this tire, the interval

  cabled belt layer consisting of circumferential cords

  is equal to 1.4 mm and the Shore A hardness of the coating

  Rubber content is 75.

  2. A tire A in accordance with the form of

  preferred embodiment of the present invention, wherein

  range of cords in the belt layer consisting of

  circumferential wheats is 1.4 mm in the central zone

  at the opposite side zones, without altering the hardness of the rubber coating between the central zone and the opposite lateral zones, and with

  Shore A hardness set at 700.

  3. A tire B according to the present invention

  having the same constitution as described by reference

  to the embodiment shown in Figure 3.

  After subjecting these tires to a drum rolling test for more than 5000 km under normal load, the amount of uneven wear in the tires was measured.

  opposite side zones on the outer surface of the

  of rolling and the length of the cracks produced by the separation along the axial direction of the layer of

  belt formed by circumferential cords the most to the ex-

TER AL.

  Measurement results have been obtained which are indi-

in the following table.

Z608515

Table 3

  Inflatable Pneumatic A Inflatable B

  comparison according to the invention

  ction Wiring Interval (Side Zone1 1,7 1, 7 Opposite / Central Area)

Report of the durations

coats of

1 1 0.8

chcuc (zones la-

  Opposite panels / center area) Uneven wear index (reference value 100 80 60:)

Index of lon-

crack

  res (100 value 100) As is evident from the measurement results shown in the table above,

  effectively reduce uneven wear in

  opposite surfaces on the outer surface of the tread and the detachment of the belt layer

  circumferential, by adjusting the cable gap in the belt layer of circumferential cords

  at a higher value in the oppo-

  only in the central zone, and the resistance to uneven wear and peel strength can be further improved by adjusting the hardness of the rubber coating to a lower value in the opposite lateral zones than in the central zone. That is, in accordance with

  the present invention, it is possible to obtain a pneumatic tire

  radial-beam tick suitable for aircraft and which

  works in an excellent way with long-lasting

tisfaisante.

  As mentioned above, sustainability at vi-

  high speeds corresponding to take-off and landing

  ge is guaranteed by the presence of

  circumferential cords having at least one

  width of not less than 1.1 times the surface of

  tact on the ground. In addition the rigidity in the direction of

  the axis of rotation in the ground contact area, which can not

  should not be carried out by means of the single layer of belt

  re fcrmée of cable cferential, can be increased through

  the use of belt layers made of hard-wired

  in combination with the belt layer consisting of

  circumferential wheats, which restores the stability in

  ge. In addition, the durability at the side portions of the belt layer formed of oblique cords in

  conditions of use under high load is strongly

  thanks to a complete wrap of layers formed of oblique cords by the belt layers formed of cords

  circumferences across the entire width, and with

  position of belt layers formed of oblique cords

  within the limits of the ground contact width.

  In addition, the weight can be greatly reduced by using

  cords made of organic fibers in the

  and in the layers of the carcass plies, with respect to the reinforcing system using steel cords in a tire, with the same safety factor. This can lead to a reduction in the overall weight of an aircraft and consequently to a reduction in fuel consumption.

fuel.

Claims (9)

  1. High performance tire, characterized   in that it includes, as a reinforcing element   main body, at least one toroidal carcass (1) constitutes   killed by a cabled web arranged radially by making   an angle between 90 and 75 in relation to an equiva-   torial tire, and a reinforcing belt (2).   the tread, consisting of overhead cables   disposed in an area constituting the top of the carcass and arranged parallel to each other so as to   reinforce 2a = pAY frman roll band-   said belt (2) is formed by a group (s) of several layers consisting of cords arranged parallel to the equatorial plane of the pneumat-iue and   by a second group (X) formed of several layers constituting   laid down by being inclined at a common angle   taken from 15 to 65 in relation to the equatorial plane of the tire.   that at least one of the belt layers belongs to   in the first group (X) has a larger expected width than   than 1.1 times the width (W) of the ground contact of the   tread band (16) under normal internal pressure and normal tire load conditions, that the belt layers belonging to the second group (() have different inclination directions with respect to the adjacent layers of this second group and are interposed each between any combination between   the carcass ply (1), the belt layers belong to   to the first group (X) and other belt layers belonging to the second group (1), and have a planned width not exceeding the ground contact width (W) of the tread portion (7) in conditions   normal internal pressure and normal tire load.   nor the expected width of the belt layers belonging to   to the first group (A) and which are the nearest to the sides which are located radially the innermost and the most outside.   2. High performance tire according to the re-   claim 1, characterized in that the belt (2) is con-   tituée by cords formed of organic fibers.   3. High performance tire according to the   claim 1, characterized in that the carcass (1) is   tituée by cords formed of organic fibers.   4. High performance tires according to the   2, characterized in that the carcass (1) is   tituée by cords formed of organic fibers.   5. High performance tire according to the   claim 1, characterized in that the gap between adjacent cords constituting the circumferential cord circumferential belt layer (21-24) located at least on the outermost side in the radial direction is set so that the gap at the level of the lateral zones   opposing (LW, LW ') of said belt layer is more im-   only in the central zone (CW) of the latter.   6. High performance tire according to the   5, characterized in that the lateral zones op-   (LW, LW ') of the belt layer formed by circumferential cords (21-24), in which the gap between adjacent cords is set to a relatively larger value, extend inward in the direction axial, beyond the ground contacting edges (P) of the tread (7) and fully include areas having a width no greater than about 30% of the tread width. the tread.   7. High performance tire according to the   claim 5, characterized in that the gap between the adjacent cords in the opposite side regions (LW, LW ') of the circumferential cordset belt layer (21-24), wherein the gap is set to a value   relatively larger, lies in a gamma   between about 150 and 200% of the interval between   the cords of said belt layer in the central zone the (CW).   8. High performance tire according to the   5, characterized in that the cords located in the opposite side regions (LW, LW ') of the circumferential cordstrip (21-24), in which   the interval between the cords is set at a relative value   more importantly, are covered by a coating of   rubber which has a hardness lower than that of   rubber covering the cords located in the area.   ne central (CW) belt layer.   9. High performance tire according to the   8, characterized in that the rubber coating   covering the cords in the oppo-   (LW, LW ') of the belt layer formed by circumferential cords.   conferences (21-24), in which the interval between   wired neighbors is set to a relatively higher value.   bearing, has a Shore A hardness which is between 70 and 85% of that of the rubber coating covering the cords in the central zone (CW) of the belt layer.