FR3045496A1 - TIRE WITH RADIAL OR CROSSED CARCASS WITH LARGE DIAMETER CABLES - Google Patents

Abstract

Pneumatic tire for rolling assembly, said tire comprising at least one carcass reinforcement (2) provided with cables (11), a tread (4) connected to two beads (5) via two sidewalls (6), said bulges (5) being intended to come into contact with a rim (7) having rim hook heels (7b), each bead (5) comprising at least one circumferential reinforcing element, said sidewalls (6) having, on their outer surface, a series of protuberances (8) alternating with recesses (9), each protuberance (8) being disposed on the surface of the sidewall (6), said protuberances (8) being arranged in a regular or irregular manner, and continuous, between a point A and a point E and the diameter of said cables of said carcass reinforcement is greater than 1 mm or the cables of said carcass reinforcement are hybrid cables.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to radial carcass or cross-carcass tires. STATE OF THE PRIOR ART

[0002] Radial-carcass tires have gradually imposed themselves on various markets, and in particular the tire market for passenger vehicles. This success is due in particular to the endurance, comfort and low rolling resistance qualities of radial technology.

The main parts of a tire are the tread, the sidewalls and the beads. The beads are intended to come into contact with the rim. In a tire of radial technology, each of the main parts constituting the tire, namely the tread, the sidewalls and the beads, has functions well separated from each other, and therefore has a specific constitution well known.

The radial tire is substantially reinforced by a carcass reinforcement comprising at least one carcass ply having an angle substantially equal to 90 ° with respect to the circumferential direction of the tire. This carcass reinforcement and radially surmounted outside and under the tread, reinforcing plies forming a belt.

The cross-carcass tire is distinguished from a tire of radial technology by the presence of at least two crossed carcass plies whose angle is different from 90 ° with respect to the circumferential direction of the tire. Tablecloths are said to be "crossed" because the angles are of opposite signs from one tablecloth to another.

It is recalled that, according to the invention, the circumferential direction of the tire is the direction in a plane perpendicular to the axis of rotation of the tire and tangent to the belt reinforcement of the tire.

Following the appearance of radial tire carcass, some cross-carcass tires have also been provided with a belt reinforcement under the tread.

In both types of tire, the tread, in contact directly with the ground, has a particular function to ensure contact with the road and must adapt to the shape of the ground. The flanks, meanwhile, absorb the irregularities of the ground while transmitting the mechanical forces necessary to carry the load of the vehicle and ensure its movement.

The belt reinforcement is an armature which must, on the one hand, be sufficiently rigid vis-à-vis the edge deformations so that the tire develops the drift thrusts necessary for its guidance, and transmit the engine torque or braking, and secondly, be very flexible in bending, that is to say allow variations in curvature of its plane to ensure a contact surface of the tire on the ground sufficient.

Therefore, the belt reinforcement generally has a composite structure, allowing it to have the required rigidity for a relatively low weight. The belt reinforcement generally consists of at least two plies with different angles, including reinforcements, cable-shaped, coated with rubber. The reinforcing elements are crossed from one sheet to the other with respect to the circumferential direction and are symmetrical or not with respect to this direction.

It is already known from JP2008068716A of the tire comprising flanks with external reinforcements, intended to reduce the internal temperature in the tire where deterioration can occur with use. But the provision of these reinforcements on the sidewall does not properly reinforce the sidewalls of a tire during side impacts, such as shocks on the sidewalks or in potholes. Indeed, such shocks performed at different speeds and / or with different angles of attack, on conventional tire architectures can cause damage, which can sometimes go as far as the scrapping of the tire.

In addition, the current trend of using aluminum rims, rather than steel to contribute in particular to the overall aesthetic appearance of the vehicle, has the consequence of causing, during side impacts on the tire, the rupture constituents of the carcass from significantly lower speeds. Furthermore, the current desire to use tires with smaller and smaller sidewall heights further has the consequence that a shock on such sidewalls causes degradation with a higher intensity than with larger sidewalls. , and therefore more deteriorating for the tire.

It is still known from JP2003 237317 a tire comprising discontinuous portions of elastomeric gum having different stiffnesses, and disposed on the sidewalls so as to reduce the noise inherent in its operation.

The patent FR888 453 also discloses pneumatic envelopes whose two sides comprise elastomeric rubber projections intended to verify that the pressure of the tire is consistent with the load due to the geometric shape they have.

Finally, US2 354 715 discloses the presence of elastomeric gum growths comprising metal elements, and disposed on the ends of the tread of a tire intended to prevent slippage during travel.

Moreover, during an impact with a sidewalk or with a pothole, the tire can be damaged, for example by wedging between the rim and the obstacle. Following such impact, reinforcement elements of the tire sidewall may be damaged. The tire may locally deform and / or lose its inflation pressure. Several known solutions make it possible to reduce these risks. For example, an increase in the breaking strength of the cables of the carcass reinforcement according to one of the following approaches: - increase of the breaking stress of the material (example: aramid or hybrid cable of aramid / nylon or aramid type / PET); - increase of the section of reinforcements (example: cables of larger diameter); - Increasing the number of reinforcing layers (typically bi-layer solutions).

Increasing the breaking strength of cables by increasing the diameter of the cable or by increasing the breaking stress of the material is normally performed at global iso-force rupture of the web. This leads to more distant cables.

This causes visual defects on the sidewall of the tire, often in wave or wave form.

In the case where alternating cables of different rigidity (in particular a PET and nylon cable or a nylon and aramid cable or a hybrid type aramid / nylon or aramid / PET or other) visual defects can appear to see the geometry of the cable on the outer surface of the sidewall.

The increase in the thickness of the sidewall or the decrease of the pitch between the reinforcing cables can limit the superficial deformations of the tire sidewall. These solutions are expensive and penalize performance because more material is used than is necessary for the proper functioning of the tire.

There is therefore still a need to be able to further improve the robustness of the tire sidewalls vis-à-vis side impacts, without changing their current dimensions.

SUMMARY OF THE INVENTION

To do this, the invention provides a tire for a wheel assembly comprising a rim and a tire, said tire comprising at least one carcass reinforcement provided with cables and radially surmounted on the outside of a crown reinforcement, it -even radially inside a tread having two axially outermost ends, said crown reinforcement consisting of at least one layer of reinforcing elements, said tread being connected to two beads by the intermediate of two flanks, said beads being intended to come into contact with a rim having rim hook heights, each bead having at least one circumferential reinforcing element, said flanks comprising, on their outer surface, a series of alternating protuberances with depressions, each protuberance being disposed at the surface of the sidewall, said protuberances being arranged regularly or irregularly, between a point A and a point E, the position of the point A being disposed at the intersection of the radially outer surface of the tread and the sidewall, and a radial axis ZZ 'distant from the equatorial plane AA' having a width LA of between 1/4 (L-60mm) and 1/4 (L-10mm), L being the nominal flange size, and said point E being disposed, at choice, in a radius included in: oR2 <E <(0.75 Ri + 0.25R2), R2 being the radius of the top of the rim hook and Ri being the radius of the nominal rim size (Interval I), or in oO, 95Ri <E <(0.75Ra + 0.25Ri), Ri being the radius of the nominal coil size, and RA being the radius of point A (Interval II), and the diameter of said cables of said armature carcass is greater than 0.9mm; the cables of said carcass reinforcement are hybrid cables.

It is considered here that a large cable is a cable whose diameter is greater than 0.9mm and more preferably greater than 1mm. This architecture makes it possible to minimize the impact of the superficial flank deformations caused by the use of carcass cables of large diameter. A double advantage is thus obtained, with, on the one hand, an increase in the rigidity of the reinforcements of the carcass reinforcement and therefore of the robustness of the tire in the face of impacts, and, on the other hand, an optimization of the visual rendering at the flanks. , because of the presence of the protuberances. Finally, these advantages are obtained without any penalty on other performance such as rolling resistance. When the protuberance partially interrupts the groove, this interruption is performed between 2 and 97% of the total axial distance of said groove, preferably between 20 and 80%, and more preferably between 30 and 50%.

The groove is an area of a given width located around the point A, and having a longitudinal void ratio greater than 70%.

R1 can be in the range between (0.8R2 + 0.2RA) and (0.2R2 + 0.8Ra).

The tire according to the invention has the advantage of being quick and easy to achieve, and to withstand particularly violent side shocks without creating significant damage that could possibly cause significant risks to the vehicle passengers. The tire according to the invention also has the advantage of having overall performance, such as rolling resistance, wear, endurance, similar to those of tires without protuberances on the sidewall.

Advantageously, said tread comprises, at least one axially outermost end, a circumferential groove.

According to a first variant, at least one protuberance partially or totally interrupts said circumferential groove. According to another variant, each protuberance is adjacent to the circumferential groove. According to another variant, at least two adjacent or non-adjacent protuberances penetrate into said circumferential groove.

Advantageously, said hybrid cables of the carcass reinforcement are aramid / nylon or aramid / PET.

Preferably, the height in the center of the protuberance is defined as follows: i) the point EQ is the most axially outside point of the sidewall of the tire; ii) the point EQ is placed at a distance REQ from the axis of rotation; iii) the height of the protuberances at point EQ is less than that at distances REQ + 10mm and REQ-10mm with respect to the axis of rotation.

Preferably, at least two protuberances have a length different from each other. Preferably, each protuberance has an average height of between 3 and 10 mm and more preferably between 5 and 8 mm.

The height of the protuberance can be variable. The maximum height of the protuberances is between 3 and 10mm. The minimum height may be close to 0. More preferably, the maximum height of the protuberances is between 4 and 8 mm. Preferably, each protuberance has an average width of between 4 and 12 mm.

The protuberances may have an average height greater than 80% of the maximum height over at least 80% of the distance between the points A and E. The average height is defined as being the average of the height between the ends of the body. a protuberance.

The protuberances preferably have a rake angle of less than or equal to 20 °, and preferably between 5 and 8 °.

Two adjacent protuberances may be spaced from each other by an average distance less than or equal to 2 times the average width of a protuberance, and may be substantially parallel to each other.

The protuberances preferably cover at least 40% of the total circumferential surface of the sidewall between points A and E.

Each protuberance, of defined geometric shape or any one, may comprise a neutral fiber, passing through a radially innermost end and a radially outermost end, and having an angle β, with respect to the radial direction ZZ ' between -60 ° and + 60 °.

The outer sidewall of the tire (that is to say outside when mounted on the vehicle) and the inner side of the tire (that is to say inside when mounted on the tire). vehicle) may comprise each of the protuberances in any combination of possible inclinations. Similarly, the four tires of a vehicle may have variable inclinations depending on each axle and / or on the same axle.

Preferably, the hollow between two adjacent protuberances extends axially in the extension of the hollow of a circumferential groove of the tread, passing through the point A, said groove being disposed on at least one axial end of the tread. tread.

Preferably, the hollow between two adjacent protuberances has an angle, with the circumferential direction between -15 ° and + 15 ° in a zone of the sidewall close to the point A, that is to say between 3 and 8 mm.

The tire according to the invention may have a ratio [sum of the total widths of each protuberance in the circumferential direction on a radius / 2πΡ greater than or equal to 30%, and more preferably equal to 60%, the widths of each protuberance being defined at 50% of the total height of said protrusion and for any radius R of the tire in the interval Re <R <Ra with Ra the radius of the point A and Re the radius of the point E.

The protrusion may be present over the entire circumferential length of the tire sidewall. The protuberances present on the flanks are advantageously made of a material identical to that of the flanks.

The invention also provides a mounted assembly comprising a rim and the tire as described above.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described with the aid of the examples and drawings which follow and which are given purely by way of illustration, and in which: FIG. 1 represents, schematically, the section of FIG. a tire of the invention according to a radial plane, - Figures 2A and 2B show, schematically and in three dimensions, a portion of a sidewall and the corresponding tread of a tire according to the invention, - FIG. 3 schematically represents an enlarged portion of a sidewall comprising protuberances of a tire according to the invention; FIG. 4 represents a sectional view of two adjacent protuberances of a tire according to the invention; along the axis AA of FIG. 3, FIGS. 5A and 5B show, in a first variant, a portion of a radially outer portion of a sidewall and the corresponding tread in three dimensions of a According to a second variant, FIG. 6A shows a portion of a radially outer portion of a flank and the corresponding tread in three dimensions, some of whose protuberances completely interrupt a circumferential groove of a According to another embodiment, FIG. 6B shows a portion of a radially outer portion of a flank and the corresponding tread in three dimensions, some of whose protuberances partially interrupt a circumferential groove of a According to the invention, FIG. 7A is a partial view in radial section of part of a sidewall and a part of the corresponding tread according to another variant, FIG. 7B represents a partial view. in radial section of a portion of a sidewall and a part of the corresponding tread according to another variant of a pneumatic tire. According to the invention, FIGS. 8A and 8B schematically represent the various layers of a tire having large cables or hybrid cables in the absence (FIG. 8A) and in the presence (FIG. 8B) of protuberances, Figure 8C is a sectional view of a cable according to the invention - Figure 9 shows a table detailing the evolution of the thickness of the cable diameter in relation to the thickness of the sidewall.

In the different figures, identical or similar technical elements bear the same reference. Their description is not repeated so as not to weigh down the text.

DETAILED DESCRIPTION OF THE INVENTION DEFINITIONS

Hereinafter denoted by: - "longitudinal or circumferential direction": rolling direction of the tire, - "radial direction": direction intersecting the axis of rotation of the tire and perpendicular to it, - "axial direction ": Direction parallel to the axis of rotation of the tire, -" radially inner to ": means closer to the axis of rotation, -" radially outside to ": means further from the axis of rotation, -" plane equatorial or median plane ": plane perpendicular to the axis of rotation of the tire and which divides the tire into two substantially equal halves, -" transverse direction of the tire ": direction parallel to the axis of rotation, -" radial or meridian plane ": A plane that contains the axis of rotation of the tire.

By the terms "partially interrupts" is meant that the radially upper end of a protuberance partially intersects the circumferential groove.

By the terms "completely interrupts" is meant that the radially upper end of a protuberance reaches the axially outer end of the tread which is closest thereto.

By the term "regular", it is defined that the protuberances arranged between the points A-E are disposed vertically to one another in a radial direction, with possibly symmetry, and uniformly.

By the term "irregular", it is defined that the protuberances arranged between the points A-E are arranged in an offset manner in two parallel radial directions without symmetry and non-uniformly.

The radius RA is a function of the width LA, itself a function of the width L.

We define the nominal flange size L by the coil size of a tire mounted on the rim and inflated; the flange size being, according to the invention, the distance between the outside of the flanks of an inflated tire, by incorporating the surface relief of the flanks. Ri corresponds to the radius of the point on the outer surface of the flank furthest from the median plane. The definition according to the invention of the flange size is adaptable to any type of envelope combined with any type of rim.

REQ being the radius at the widest point of the tire (width = L): it is preferably Ra> REQ.

As shown in Figure 1, the tire for passenger vehicle general reference 1 comprises a radially inner carcass reinforcement 2 to a general reference belt reinforcement 3, said belt reinforcement 3 being radially inside a strip bearing 4 itself connected to two beads 5 via two sidewalls 6. The beads 5 are intended to come into contact with a rim 7 (partially shown). Each bead comprises at least one circumferential reinforcing element 7a. The flanks comprise, on their surface, a series of protuberances 8 regularly alternating with recesses 9 (shown in FIG. 2). In Figure 1 we can see a protrusion 8, in section, having a continuous neutral fiber. It is recalled here that a neutral fiber is called a neutral axis which passes substantially in the center of the volume of each protuberance, and which undergoes neither shortening nor elongation when it is subjected to compression and / or depression.

As shown in Figure 1, the protuberances 8 are disposed on the surface of the sidewall, a continuous neutral fiber length which extends from a point A to a point E.

The point E can be arranged according to two approaches, designated here interval I and interval II. o According to the interval I, the radius of the point E is: R2 <E <(0.75 + 0.25R2), R2 being the radius of the top of the rim hook 7b and Ri being the radius of the nominal flange size. o According to the interval II, the radius of the point E is: 0.95Ri <E <(0.75Ra + 0.25 R ^, Ri being the radius of the nominal flange size, and RA being the radius of the point A.

According to an exemplary embodiment, the point E is disposed at a radius of 232 mm for a reference tire 205/55 R 16 mounted on a rim 6.5 J 16 for which RA is equal to 298 mm, R2 is equal to 220 mm, and Ri is equal to 261 mm.

The point A is disposed at the intersection of the radially outer surface of the tread and the sidewall, and a radial axis ZZ 'distant from the equatorial plane AA' with a length LA of 1/4 (L-60mm) and 1/4 (L-10mm), where L is the nominal flange size, For a 205/55 R16 reference tire, RA is equal to 298mm.

The protuberances are not inserted rubber elements, added in the rubber flanks, but are obtained by molding during the baking step. They are obtained in a manner similar to that of the sculptures made on the tread.

FIG. 2A represents an alternation of protuberances 8 and recesses 9, shown enlarged in FIGS. 3 and 4. FIG. 2B represents a variant of FIG. 2A in which the protuberances are arranged at an angle to the axial direction. According to this embodiment, the longest continuous protuberances 8 have a neutral fiber length of about 75 mm for a tire of dimension 205/55 R 16. They are arranged radially (FIG. 2) substantially parallel to one another others, are spaced about 4.50mm, have a height of about 6mm, and a width of about 8.6mm in their axially innermost part.

The clearance angle α is about 8 ° as shown in Figure 4. Such a clearance angle value allows a release of the tire after firing without deterioration of the final structure. According to this embodiment, the protuberances have a ratio [sum of the widths of each protuberance in the circumferential direction on a radius Ri] / 2nR equal to 30%, at mid-height and have no angle with respect to the radial plane.

FIG. 5A shows a three-dimensional representation of the radially outer portion 8a of the protuberances 8 and its enlargement in FIG. 5B of FIG. 5A. In these Figures 5A and 5B, the portion 8a of each protrusion 8 and the recesses 9 are adjacent to a groove 10 disposed circumferentially on the surface of the tread 4 at its axially outermost end 4a. The groove 10 is not interrupted in its length. According to this particular embodiment, the groove 10 has an axial width "I" along the axis YY 'which can be between 2 and 10 mm, and a radial height "h" along the axis ZZ' of between 3 and 8 mm.

Figure 6A also shows a three-dimensional representation of the radially outer portion 8a of the protuberances 8. Unlike Figures 5A and 5B, the groove 10 is interrupted. Indeed, the end 8a of the protuberances 8 and adjacent recesses 9 completely cut the groove 10 in the circumferential direction of the tire. FIG. 6B shows another variant of a three-dimensional representation of said radially outer portion 8a of the protrusions 8. In this figure, the protuberance 8 partially cuts the groove 10 in the circumferential direction of the tire.

FIGS. 7A and 7B show that the radially inner portion 8b (shown in dotted lines) of the protrusion 8 is spaced a thickness "d" from the radially inner portion 10b of the groove 10. This thickness "d" is smaller at 2mm, and preferably less than 1mm.

Figures 8A and 8B illustrate embodiments, more particularly at the level of the weld of the carcass reinforcement. In these examples, the cable has a diameter greater than 0.9 mm. Figure 8A clearly illustrates the deformation which causes a ripple phenomenon causing the appearance defect. In this case, the extra thickness resulting from the large diameter cables is of the order of 800 microns. A depression or wavy appearance is then visible on the sidewall. This depression is a function of the diameter of the cable and the thickness of the sidewall. Figure 8B shows the recommended solution, which reduces the visual impact, thus removing the appearance defect.

Figure 8C illustrates an embodiment of a hybrid cable 11 according to the invention wherein the smallest part is made of aramid and the largest part is made of nylon.

The graph of Figure 9 shows the impact of the cable diameter and the thickness of the sidewall on the level of deformation of the sidewall for flank thicknesses of 3 and 5mm. The curves with the squares and diamonds concern classical architectures. It is observed that the level of deformation reaches important values when the large diameters of cables are used. The boxed area identifies configurations for which the appearance defects are well above allowable thresholds. It is observed that the curve presented with crosses, corresponding to the tire according to the invention, provides a particularly favorable effect, with deformation levels significantly reduced compared to conventional arrangements.

[0065] Advantageously, the minimum distance between the outer surface and the cable is 3.1 mm. The minimum protrusion height is of the order of 3mm.

Figure 8C illustrates another type of solution, based on hybrid cables. A hybrid reinforcement is a textile reinforcement that comprises a combination of at least two different textile materials. For example, the Hybrid Reinforcement A167 / A167 / N140 280/280 consists of three strands including two Aramid strands of 167 tex and a nylon strand 140 tex with a twist of 280 turns per meter (rpm). These three strands are twisted together with a balanced twist of 280 rpm. Here are some examples of hybrid cables: A330 / A330 / N188 230/230 A167 / A167 / N140 280/280 A167 / N140 290/290 FIG. 8C is a schematic representation of a section of a cable A167 / A167 / N140. The dark strands are the nylon strands, and the light strand is the aramid strand. The concept of the invention allows the implementation of such cables, without the previously mentioned appearance defects.

Thus, the present invention allows to associate the solutions corresponding to either: an increase in the rigidity of the cables by increasing the section of the reinforcements (example: larger diameter cables); or an increase in the rigidity of the cables using multi-material cables (in particular a hybrid cable of aramid / nylon or aramid / PET type).

With a provision on the sidewall of the tire of a set of protuberances and recesses which limit the effects of corrugation of the sidewalls.

The tire according to the invention is obtained after baking and molding in a baking mold in a conventional manner.

1 Pneumatic 2 Carcass reinforcement 3 Belt reinforcement 4 Tread 4a Extremely axially outermost end of the tread 5 Bead 6 Sidewalls 7 Rim 7a Circumferential reinforcement 7b Top of rim hook 8 Protrusions 8a Extremity of protuberances 8b, 8c, 8d Radially inner portion of protrusion 9 Hollow 10 Circumferential groove 10b Radially inner portion of groove 11 Large diameter cables or hybrid cables

Claims (20)

A tire for a wheel assembly comprising a rim and a tire, said tire comprising at least one carcass reinforcement (2) provided with cables (11) and radially surmounted externally of a crown reinforcement (3), itself same radially inside a tread (4) having two axially outermost ends, said crown reinforcement (3) consisting of at least one layer of reinforcement elements, said tread (4 ) being connected to two beads (5) via two sidewalls (6), said beads (5) being intended to come into contact with a rim (7) having rim hook tops (7b), each bead (5) comprising at least one circumferential reinforcing element, said sidewalls (6) having, on their outer surface, a series of protuberances (8) alternating with recesses (9), characterized in that each protuberance (8) is arranged on the surface e of the sidewall (6), said protuberances (8) being arranged regularly or irregularly and continuously between a point A and a point E, the position of the point A being disposed at the intersection of the radially outer surface of the tread and the sidewall, and a radial axis ZZ 'distant from the equatorial plane AA' with a width LA of between 1/2 (L-60mm) and 1/4 (L-10mm), L being the nominal flange size, and said point E being arranged, optionally, in a radius included in: o R2 <E <(0.75 Ri + 0.25R2), R2 being the radius of the top of the rim hook and Ri being the radius of the nominal coil size - (Interval I), or in 0.95Ri <E <(0.75Ra + 0.25 Ri), R! being the radius of the nominal coil size, and RA being the radius of the point A (Interval II), and in that: - the diameter of said cables of said carcass reinforcement is greater than 0.9mm; or the cables of said carcass reinforcement are hybrid cables. 2. A tire according to claim 1, characterized in that said tread (4) comprises, at at least one axially outermost end (4a), a circumferential groove (10). 3. A tire according to claim 2, characterized in that at least one protrusion (8) interrupts partially or completely said circumferential groove (10). 4. A tire according to claim 2, characterized in that each protuberance is adjacent to the circumferential groove (10). 5. A tire according to claim 2, characterized in that at least two adjacent protuberances or not penetrate into said circumferential groove (10). 6. A tire according to one of the preceding claims, characterized in that said hybrid cables (11) of the carcass reinforcement are aramid / nylon or aramid / PET. 7. A tire according to one of the preceding claims, characterized in that the height in the center of the protuberance is defined as follows: i) the point EQ is the most axially outer point of the sidewall of the tire; ii) the point EQ is placed at a distance REQ from the axis of rotation; iii) the height of the protuberances at point EQ is less than that at distances REQ + 10mm and REQ-10mm with respect to the axis of rotation. 8. A tire according to one of the preceding claims, characterized in that at least two protuberances (8) have a length different from one another. 9. A tire according to one of the preceding claims, characterized in that each protuberance (8) has an average height of between 3 and 10 mm and more preferably between 5 and 8 mm. 10. A tire according to one of the preceding claims, characterized in that each protuberance (8) has an average width of between 4 and 12 mm. Pneumatic tire according to one of the preceding claims, characterized in that each protuberance (8) has an average height greater than 80% of the maximum height over at least 80% of the distance between the points A and E. 12. A tire according to one of the preceding claims, characterized in that each protuberance (8) has a rake angle of less than or equal to 20 °, and preferably between 5 and 8 °. 13. A tire according to one of the preceding claims, characterized in that two adjacent protuberances (8) are spaced from each other by an average distance less than or equal to 2 times the average width of a protuberance. Tire according to one of the preceding claims, characterized in that two adjacent protuberances (8) are substantially parallel to one another. 15. A tire according to one of the preceding claims, characterized in that the protuberances (8) cover at least 40% of the total circumferential surface of the sidewall between points A and E. 16. A tire according to one of the preceding claims, characterized in that each protuberance (8), of definite geometric shape or any, comprises a neutral fiber, passing through a radially innermost end and a radially outermost end, and having an angle β, with respect to the radial direction ZZ ', of between -60 ° and + 60 °. 17. A tire according to one of the preceding claims, characterized in that the hollow (9) between two adjacent protuberances (8) extends axially in the extension of the hollow of a circumferential groove of the tread, passing through the point A, said groove being disposed on at least one axial end of the tread. 18. A tire according to one of the preceding claims, characterized in that two adjacent protuberances (8) form a hollow between them which has an angle, with the circumferential direction between -15 ° and + 15 ° in an area of the near flank. point A. 19. Tire according to one of the preceding claims, characterized in that it has a ratio [sum of the total widths of each protuberance in the circumferential direction on a radius R1] / 2πΡ greater than or equal to 30%, and more preferably higher or equal to 60% and less than or equal to 70%, the widths of each protuberance (8) being defined at 50% of the total height of said protrusion (8) and the radius R of the tire being in the interval Re < R <Ra with RA the radius of point A and Re the radius of point E. 20. Mounted assembly comprising a rim and a tire as defined in one of the preceding claims.