Tyre

Abstract

The present invention relates to a tyre comprising a plurality of lateral grooves (23), two sidewalls comprising a series of projections (28) alternating with voids (29), each of the projections comprising an upper face (281) spaced away from the sidewall (26) and at least three lateral faces (282) extending from the sidewall to the upper face (281) and, with an imaginary straight line indicating a centre of the void being inclined by an angle A, the lateral face (282) extending substantially parallel to the outer axial end of the tread being situated so as to completely cross an imaginary extension of the lateral groove (23), and the lateral faces (282) of circumferentially adjacent projections (28) having an overlap in the radial direction. The circumferential width wp of each projection (28) is at least equal to 150% of the width W of the corresponding lateral groove (23) and at most equal to 110 mm.

Description

[0001] Pneumatic

[0002]

[0001] The present invention relates to a tire. The invention relates, in particular, to a tire sidewall portion design intended to improve endurance performance, with an aesthetically attractive design, while maintaining comfort performance.

[0003]

[0002] In recent years, there has been an increase in the number of TTL (recreational off-road) vehicles. A TTL tire is often intended to be driven primarily on paved roads, but must also have an appropriate level of off-road performance. A tire is known to have projections on a sidewall portion that does not normally come into contact with the ground except when traveling off-road, thereby providing adequate off-road performance. The projections also make the tire aesthetically appealing.

[0004]

[0003] Document JP2004291936 discloses a pneumatic tire comprising a pair of bead wires, a carcass wound around the bead wires and formed into a toroidal shape, belt layers placed outside, in a radial direction of the tire, a crown portion of the carcass, and a tread rubber placed outside, in the radial direction of the tire, relative to the belt layers, wherein a plurality of projections having a height of 5 mm or more are placed on a shoulder portion in a spaced manner in a peripheral direction of the tire R, and the area of ​​a lower surface of the projection is such that it is at least twice the area of ​​an upper surface of the projection.

[0005]

[0004] Document JP2004291937 discloses a pneumatic tire comprising a pair of bead wires, a carcass, belt layers and a tread rubber, wherein a plurality of protrusions having a height of 5 mm or more are provided on a shoulder portion spaced apart in a peripheral direction of the tire R, one or a plurality of ribs connecting the protrusions are provided between adjacent protrusions, the height of the rib being 50 to 100% of the height of the protrusion, the length, in a radial direction of the tire A, being increased from an upper surface of the rib to a lower surface, and the total sum of the lengths, in the radial direction of the tire A, of the lower surfaces of the ribs between adjacent protrusions being such that it is at least 40% of the length, in the radial direction of the tire A, of an upper surface of the protrusion.

[0006]

[0005] Document US20190315164 discloses a tire having a protrusion on a shoulder portion. The protrusion comprises a side wall protruding from a surface of the shoulder portion, and a top wall disposed at a distal end of the side wall. The side wall comprises portions facing each other in a circumferential direction of the tire. Each of the portions is inclined in the circumferential direction of the tire such that a protrusion height which is a distance of the protrusion relative to the surface of the shoulder portion gradually decreases from the top wall toward the surface of the shoulder portion. An inclination angle of each of the portions in the circumferential direction of the tire relative to the surface of the shoulder portion gradually decreases from the inside toward the outside in the radial direction of the tire.

[0007]

[0006] Document US20190193477 discloses a pneumatic tire comprising a pair of bead portions, a pair of sidewall portions, a tread portion, a plurality of lug grooves extending from a shoulder region of the tread portion to a shoulder region of the sidewall portion, and a block defined by the plurality of lug grooves, the block comprising a shoulder block formed in the shoulder portion and a shoulder block formed in the shoulder portion, at least some of the plurality of lug grooves terminating at a connecting portion connecting each pair of shoulder blocks, the connecting portion being provided on an inner side, in the tire diametrical direction, of a point corresponding to 50% of the length, in the tire diametrical direction, of the shoulder block from an upper end point of the shoulder block,a platform or projection being formed at the location where the shoulder block has the maximum raised height at the tire diametrical location of the connecting portion.,

[0008]

[0007] Document US20210170805 discloses a tire comprising a first platform portion which is formed on a sidewall portion, protrudes toward an outer side in a tire width direction, and extends in a tire circumferential direction over the entire circumference of the tire, and a plurality of second platform portions which are formed in a central portion, in a tire radial direction, of the first platform portion, protrude toward an outer side in the tire width direction, extend in the tire circumferential direction, and are mutually spaced apart in the tire circumferential direction.

[0009]

[0008] Document US20190077198 discloses a tire comprising a sidewall region extending in a radial direction of the tire, the sidewall region comprising a plurality of protruding regions which protrude in a width direction of the tire, a dimension, in a circumferential direction of the tire, of at least one of the protruding regions being greater than a dimension of a gap, in the circumferential direction of the tire, between an adjacent pair of the protruding regions, and the at least one protruding region being provided with a recess at a side face on one side in the circumferential direction of the tire.

[0010]

[0009] The state of the art of the tires described in US2020346497, US2011253278 and EP0508091 is known.

[0011]

[0010] However, with the solutions disclosed in these documents, an improvement in endurance performance is not sufficient since a crack starting in a tread easily propagates to the sidewall through a lateral groove. These solutions also have an impact on comfort performance since the protrusions reduce sidewall flexibility. It is therefore desired to improve the endurance performance of a tire provided with protrusions with an aesthetically appealing design while maintaining a reasonable level of comfort performance.

[0012]

[0011] A tire providing improved endurance performance, with an aesthetically appealing design, while maintaining a reasonable level of comfort performance is therefore necessary.

[0013]

[0012] Definitions:

[0014]

[0013] A “radial direction / orientation” is a direction / orientation perpendicular to an axis of rotation of the tire. This direction / orientation corresponds to the thickness orientation of the tire.

[0015]

[0014] An “axial direction / orientation” is a direction / orientation parallel to the tire’s axis of rotation.

[0016]

[0015] A “circumferential direction / orientation” is a direction / orientation that is tangent to any circle centered on the axis of rotation. This direction / orientation is perpendicular to both the axial direction / orientation and the radial direction / orientation.

[0016] A “tire” means all types of elastic tire, whether or not subject to internal pressure.

[0017]

[0017] The "tread" of a tire means a quantity of rubber material delimited by lateral surfaces and by two main surfaces, one of which is intended to come into contact with the ground when the tire is rolling.

[0018]

[0018] An objective of the invention is therefore to propose a tire which provides an improvement in endurance performance, with an aesthetically attractive design, while maintaining a reasonable level of comfort performance.

[0019]

[0019] The present invention relates to a tire for a rolling assembly comprising a rim and a tire, the tire comprising a tread intended to come into contact with the ground during rolling via a contact face and having two outer axial ends, the tread comprising a plurality of lateral grooves of width W opening onto both the contact face and one of the two outer axial ends of the tread and extending generally in the axial direction of the tire, the tread being connected, via two sidewalls, to two bead regions intended to be fitted on the rim, at least one sidewall comprising, on its outer surface, a series of projections each having a circumferential width wp and a radial length Ip, alternating circumferentially with voids of a circumferential width wv,each of the projections being spaced radially inwardly from the outer axial end of the tread by a radial distance D, each of the projections having an upper face spaced from the sidewall surface by a minimum height hpm which is greater than a height of any character and / or design molded on the sidewall other than the projections and by a maximum height hpx, at least three side faces extending from the sidewall surface to the upper face, one of the at least three side faces located radially closest to the tread extending substantially parallel to the respective one of the two outer axial ends of the tread, an imaginary straight line indicating a center of the void being inclined at an angle A to the radial direction,the lateral face of the projection located radially closest to the tread extending substantially parallel to the respective one of the two outer axial ends of the tread being located so as to completely intersect an imaginary extension VEL of at least one of the plurality of lateral grooves, and the lateral faces of circumferentially adjacent projections forming the void having an overlap in the radial direction, the circumferential width wp being at least equal to 150% of the width W of the corresponding lateral groove and at most equal to 110 mm.,

[0020]

[0020] This structure provides improved endurance performance, with an aesthetically appealing design, while maintaining a reasonable level of comfort performance.

[0021]

[0021] Since the lateral face of the projection located radially closest to the tread extending substantially parallel to the respective one of the two outer axial ends of the tread is located so as to completely intersect an imaginary extension VEL of at least one of the plurality of lateral grooves, it is possible, by means of the projection, to prevent the propagation of a crack starting in the tread through the lateral groove radially toward the inside of the tire. Therefore, it is possible to improve the endurance performance.

[0022]

[0022] Since the void is inclined at an angle A with respect to the radial direction, and the side faces of circumferentially adjacent projections forming the void have an overlap in the radial direction, it is possible to further prevent the propagation of a crack initiating in the tread through the lateral groove radially toward the inside of the tire. Therefore, it is possible to further improve the endurance performance.

[0023]

[0023] Since the projection has an upper face spaced from the sidewall surface by a minimum height hpm that is greater than a height of any character and / or design molded on the sidewall other than the projections and a maximum height hpx, the projection can provide an attractive appearance to the sidewall. Therefore, it is possible to improve the aesthetically appealing design of the tire.

[0024]

[0024] Since the series of protrusions are formed so as to circumferentially alternate with voids, and the protrusion is spaced radially inward from the outer axial end of the tread, an impact on sidewall flexibility can be minimized. Therefore, it is possible to maintain a reasonable level of comfort performance.

[0025]

[0025] Since circumferential width wp of the projection is less than 150% of the width W of the corresponding lateral groove, there is a risk that an ability to prevent propagation by means of the projection decreases, so that there would be no improvement in endurance performance. If this circumferential width wp of the projection is greater than 110 mm, there is a risk that an increase in the stiffness of the sidewall becomes impossible to ignore, this giving rise to a degradation in comfort performance. By setting this circumferential width wp of the projection to a value at least equal to 150% of the width W of the corresponding lateral groove and at most equal to 110 mm, it is possible according to the invention to improve endurance performance while maintaining a reasonable level of comfort performance.

[0026]

[0026] In another preferred embodiment, the maximum height hpx of the projection is between 1.0 mm and 8.0 mm inclusive.

[0027]

[0027] If this maximum height hpx of the protrusion is less than 1.0 mm, there is a risk that an ability to prevent propagation by means of the protrusion decreases, so that there would be no improvement in endurance performance. If this maximum height hpx of the protrusion is greater than 8.0 mm, there is a risk that an increase in sidewall stiffness becomes impossible to ignore, resulting in a deterioration in comfort performance, and a risk of reducing the manufacturing efficiency of the tire provided with the protrusions. By setting this maximum height hpx of the protrusion between 1.0 mm and 8.0 mm inclusive, it is possible to improve endurance performance while maintaining a reasonable level of comfort performance and the productivity of the tire provided with the protrusions.

[0028]

[0028] The maximum height hpx of the projection is preferably between 1.2 mm and 7.0 mm inclusive, more preferably between 1.5 mm and 6.0 mm inclusive.

[0029]

[0029] In another preferred embodiment, the angle A of the imaginary straight line indicating the center of the void is between 15° and 75° inclusive.

[0030]

[0030] If this angle A of the imaginary straight line indicating the center of the void is less than 15°, there is a risk that an ability to prevent propagation by means of the protrusion decreases, so that there would be no improvement in endurance performance. If this angle A of the imaginary straight line indicating the center of the void is greater than 75°, there is a risk that an increase in the stiffness of the sidewall becomes impossible to ignore, resulting in a degradation of comfort performance. By setting this angle A of the imaginary straight line indicating the center of the void between 15° and 75° inclusive, it is possible to improve endurance performance while maintaining a reasonable level of comfort performance.

[0031]

[0031] This angle A of the imaginary straight line indicating the center of the void is preferably between 20° and 70° inclusive, more preferably between 25° and 65° inclusive.

[0032]

[0032] In another embodiment the circumferential width wp of the projection is preferably at least equal to 160% of the width W of the corresponding lateral groove and at most equal to 110 mm, more preferably at least equal to 160% of the width W of the corresponding lateral groove and at most equal to 100 mm.

[0033]

[0033] In another preferred embodiment, the radial distance D is at least equal to 2.0 mm and at most equal to 7.0 mm.

[0034]

[0034] If this radial distance D is less than 2.0 mm, there is a risk that an increase in the stiffness of the sidewall becomes impossible to ignore, this giving rise to a degradation of the comfort performance. If this radial distance D is greater than 7.0 mm, there is a risk that a crack starting in the tread and propagating through the lateral groove radially towards the inside of the tire already damages the sidewall before even reaching it and that its propagation is prevented by the projection, this giving rise to a degradation of the endurance performance. By setting this radial distance D to a value at least equal to 2.0 mm and at most equal to 7.0 mm, it is possible to improve the endurance performance while maintaining a reasonable level of comfort performance.

[0035]

[0035] This radial distance D is preferably at least equal to 2.5 mm and at most equal to 6.0 mm, more preferably at least equal to 3.0 mm and at most equal to 6.0 mm.

[0036] In another preferred embodiment, the radial length Ip of the projection is at least equal to 20 mm and at most equal to 70 mm.

[0036]

[0037] If this radial length Ip of the protrusion is less than 20 mm, there is a risk that the sidewall will have a less attractive appearance due to the protrusion. If this radial length Ip of the protrusion is greater than 70 mm, there is a risk that an increase in the stiffness of the sidewall will become impossible to ignore, resulting in a deterioration in comfort performance. By setting this radial length Ip of the protrusion to a value at least equal to 20 mm and at most equal to 70 mm, it is possible to make the tire design aesthetically more attractive while maintaining a reasonable level of comfort performance.

[0037]

[0038] This radial length Ip of the projection is preferably at least equal to 25 mm and at most equal to 60 mm, more preferably at least equal to 25 mm and at most equal to 50 mm.

[0038]

[0039] In another preferred embodiment, the circumferential width wv of the void is at least 5.0 mm and at most 15.0 mm, and a degree of circumferential overlap between two circumferentially adjacent protrusions is at least 4% and at most 15% of the circumferential width wp of the protrusion.

[0039]

[0040] If this circumferential width wv of the void is less than 5.0 mm and / or if the degree of circumferential overlap between two circumferentially adjacent protrusions is greater than 15% of the circumferential width wp of the protrusion, there is a risk that an increase in the stiffness of the sidewall becomes impossible to ignore, resulting in a degradation of the comfort performance. If this circumferential width wv of the void is greater than 15.0 mm and / or if the degree of circumferential overlap between two circumferentially adjacent protrusions is less than 4% of the circumferential width wp of the protrusion, there is a risk that an ability to prevent propagation by means of the protrusion decreases, so that there would be no improvement in the endurance performance.By setting this circumferential width wv of the void to a value at least equal to 5.0 mm and at most equal to 15.0 mm, and the degree of circumferential overlap between two circumferentially adjacent projections to a value at least equal to 4% and at most equal to 15% of the circumferential width wp of the projection, it is possible to improve endurance performance while maintaining a reasonable level of comfort performance.

[0040]

[0041] In another preferred embodiment, the projection includes an extension portion extending radially inwardly from the radially inwardly facing side face.

[0042] With this structure it is possible to produce an aesthetically attractive design since the extension part gives an original appearance to the projection.

[0041]

[0043] With the structures described above, it is possible to produce a tire that provides improved endurance performance, with an aesthetically appealing design, while maintaining a reasonable level of comfort performance.

[0042]

[0044] Other characteristics and advantages of the invention emerge from the description given below with reference to the attached drawings which illustrate, by way of non-limiting examples, the embodiment of the invention.

[0043]

[0045] In these drawings:

[0044] - [Fig. 1] Fig. 1 is a schematic plan view of a tire according to a first embodiment of the present invention;

[0045] - [Fig. 2] Fig. 2 is an enlarged schematic view illustrating a part indicated by II in Fig. 1;

[0046] - [Fig. 3] Fig. 3 is a schematic sectional plan view taken along line lll-lll in Fig. 2;

[0047] - [Fig. 4] Fig. 4 is a schematic plan view of a tire according to a second embodiment of the present invention;

[0048] - [Fig. 5] Fig. 5 is a schematic plan view of a tire according to the prior art.

[0049]

[0046] Preferred embodiments of the present invention will be described below with reference to the drawings.

[0050]

[0047] A tire 1 according to a first embodiment of the present invention will be described with reference to Figs. 1, 2 and 3.

[0051]

[0048] Fig. 1 is a schematic plan view of a tire according to a first embodiment of the present invention. Fig. 2 is an enlarged schematic view illustrating a portion indicated by II in Fig. 1. Fig. 3 is a schematic sectional plan view taken along line III-III in Fig. 2. The portions other than those illustrated in these Figs. 1 to 3 correspond to a typical radial tire construction and therefore an explanation of these portions will be omitted.

[0052]

[0049] The tire 1 is a tire for a rolling assembly comprising a rim and a tire, comprising a tread 2 intended to come into contact with the ground during rolling by means of a contact face 25 and having two outer axial ends, the tread 2 comprising a plurality of lateral grooves 3 of width W opening onto both the contact face 25 and one of the two outer axial ends of the tread 2 and extending generally in the axial direction of the tire 1, the tread 2 being connected, by means of two sidewalls 6, to two bead regions (not shown) intended to be fitted onto the rim (not shown). At least one sidewall 6 comprises, on its outer surface, a series of projections 8 each having a circumferential width wp (illustrated in Fig. 2) and a radial length Ip (illustrated in Fig. 2 and Fig.3), alternating with voids 9 of a circumferential width wv (illustrated in Fig. 2). The circumferential width wp is at least equal to 150% of the width W of the corresponding lateral groove 3 and at most equal to 110 mm. The radial length Ip of the projection 8 is at least equal to 20 mm and at most equal to 70 mm. In the present embodiment, the width W of the lateral groove 3 is 8.0 mm, the circumferential width wp of the projection 8 is 60 mm or 750% of the width W of the lateral groove 3, the radial length Ip of the projection 8 is 30 mm.

[0053]

[0050] As illustrated in Fig. 1, each of the projections 8 is spaced radially inwardly from the outer axial end of the tread 2 by a radial distance D (illustrated in Fig. 2 and Fig. 3), each of the projections 8 has an upper face 81 spaced from the surface of the sidewall 6 by a minimum height hpm (illustrated in Fig. 3) which is greater than a height of any character and / or design molded on the sidewall 6 other than the projections 8 and by a maximum height hpx (illustrated in Fig. 3), at least three side faces 82 extend from the surface of the sidewall 6 to the upper face 81, one of the at least three side faces 82 located radially closest to the tread 2 extends substantially parallel to the respective one of the two outer axial ends of the tread 2. The radial distance D is at least 2.0 mm and at most equal to 7.0 mm.The maximum height hpx of the projection 8 is between 1.0 mm and 8.0 mm inclusive. In the present embodiment, the radial distance D is 5.0 mm, the minimum height hpm is 1.0 mm, the maximum height hpx is 2.0 mm.

[0054]

[0051] As illustrated in Fig. 2, an imaginary straight line indicating a center of the void 9 is inclined at an angle A with respect to the radial direction. The side face 82 of the projection 8 located radially closest to the tread 2 extending substantially parallel to the respective one of the two outer axial ends of the tread 2 is located so as to completely intersect an imaginary extension VEL of at least one of the plurality of lateral grooves 3, and the side faces 82 of circumferentially adjacent projections 8 forming the void 9 have an overlap in the radial direction. The angle A of the imaginary straight line indicating the center of the void 9 is between 15° and 75° inclusive.The circumferential width wv of the void 9 is at least 5.0 mm and at most 15.0 mm, and a degree of circumferential overlap between two circumferentially adjacent projections 8 is at least 4% and at most 15% of the circumferential width wp of the projection 8. In the present embodiment, the angle A of the imaginary straight line indicating the center of the void 9 is 45°, the circumferential width wv of the void 9 is 10 mm, the degree of circumferential overlap between two circumferentially adjacent projections 8 is 8% of the circumferential width wp of the projection 8.

[0055]

[0052] Since the lateral face 82 of the projection 8 located radially closest to the tread 2 extending substantially parallel to the respective one of the two outer axial ends of the tread 2 is located so as to completely intersect an imaginary extension VEL of at least one of the plurality of lateral grooves 3, it is possible, by means of the projection 8, to prevent the propagation of a crack starting in the tread 2 through the lateral groove 3 radially toward the inside of the tire 1. Therefore, it is possible to improve the endurance performance.

[0056]

[0053] Since the void 9 is inclined at an angle A with respect to the radial direction, and the side faces 82 of circumferentially adjacent projections 8 forming the void 9 have an overlap in the radial direction, it is possible to further prevent the propagation of a crack starting in the tread 2 through the lateral groove 3 radially toward the inside of the tire 1. Therefore, it is possible to further improve the endurance performance.

[0057]

[0054] Since the projection 8 has an upper face 81 spaced from the surface of the sidewall 6 by a minimum height hpm which is greater than a height of any character and / or design molded on the sidewall 6 other than the projections 8 and by a maximum height hpx, the projection 8 can provide an attractive appearance to the sidewall 6. Therefore, it is possible to improve the aesthetically attractive design of the tire.

[0058]

[0055] Since the series of projections 8 are formed to circumferentially alternate with voids 9, and the projection 8 is spaced radially inward from the outer axial end of the tread 2, an impact on a flexibility of the sidewall 6 can be minimized. Therefore, it is possible to maintain a reasonable level of comfort performance.

[0059]

[0056] Since the maximum height hpx of the protrusion 8 is between 1.0 mm and 8.0 mm inclusive, it is possible to improve the endurance performance while maintaining a reasonable level of comfort performance and the productivity of the tire 1 provided with the protrusions 8.

[0057] If this maximum height hpx of the protrusion 8 is less than 1.0 mm, there is a risk that an ability to prevent propagation by means of the protrusion 8 decreases, so that there would be no improvement in the endurance performance. If this maximum height hpx of the protrusion 8 is greater than 8.0 mm, there is a risk that an increase in the stiffness of the sidewall 6 becomes impossible to ignore, this giving rise to a degradation of the comfort performance, and a risk of reducing the manufacturing efficiency of the tire 1 provided with the protrusions 8.

[0060]

[0058] The maximum height hpx of the projection 8 is preferably between 1.2 mm and 7.0 mm inclusive, more preferably between 1.5 mm and 6.0 mm inclusive.

[0061]

[0059] Since the angle A of the imaginary straight line indicating the center of the void 9 is between 15° and 75° inclusive, it is possible to improve endurance performance while maintaining a reasonable level of comfort performance.

[0062]

[0060] If this angle A of the imaginary straight line indicating the center of the void 9 is less than 15°, there is a risk that a capacity to prevent propagation by means of the projection 8 decreases, so that there would be no improvement in endurance performance. If this angle A of the imaginary straight line indicating the center of the void 9 is greater than 75°, there is a risk that an increase in the stiffness of the sidewall 6 becomes impossible to ignore, this giving rise to a degradation in comfort performance.

[0063]

[0061] This angle A of the imaginary straight line indicating the center of the void 9 is preferably between 20° and 70° inclusive, more preferably between 25° and 65° inclusive.

[0064]

[0062] Since the circumferential width wp of the projection 8 is at least equal to 150% of the width W of the corresponding lateral groove 3 and at most equal to 110 mm, it is possible to improve the endurance performance while maintaining a reasonable level of comfort performance.

[0065]

[0063] If this circumferential width wp of the projection 8 is less than 150% of the width W of the corresponding lateral groove 3, there is a risk that a capacity to prevent propagation by means of the projection 8 decreases, so that there would be no improvement in endurance performance. If this circumferential width wp of the projection 8 is greater than 110 mm, there is a risk that an increase in the stiffness of the sidewall 6 becomes impossible to ignore, this giving rise to a degradation in comfort performance.

[0066]

[0064] This circumferential width wp of the projection 8 is, preferably, at least equal to 160% of the width W of the corresponding lateral groove 3 and at most equal to 110 mm, more preferably at least equal to 160% of the width W of the corresponding lateral groove 3 and at most equal to 100 mm.

[0067]

[0065] Since the radial distance D is at least 2.0 mm and at most 7.0 mm, it is possible to improve the endurance performance while maintaining a reasonable level of comfort performance.

[0068]

[0066] If this radial distance D is less than 2.0 mm, there is a risk that an increase in the stiffness of the sidewall 6 becomes impossible to ignore, this giving rise to a deterioration in comfort performance. If this radial distance D is greater than 7.0 mm, there is a risk that a crack starting in the tread 2 and propagating through the lateral groove 3 radially towards the inside of the tire 1 already damages the sidewall 6 before even reaching it and that its propagation is prevented by the projection 8, this giving rise to a deterioration in endurance performance.

[0069]

[0067] This radial distance D is preferably at least equal to 2.5 mm and at most equal to 6.0 mm, more preferably at least equal to 3.0 mm and at most equal to 6.0 mm.

[0068] Since the radial length Ip of the projection 8 is at least equal to 20 mm and at most equal to 70 mm, it is possible to make the design of the tire 1 aesthetically more attractive while maintaining a reasonable level of comfort performance.

[0070]

[0069] If this radial length Ip of the projection 8 is less than 20 mm, there is a risk that the sidewall will have a less attractive appearance due to the projection 8. If this radial length Ip of the projection 8 is greater than 70 mm, there is a risk that an increase in the rigidity of the sidewall 6 will become impossible to ignore, this giving rise to a deterioration in comfort performance.

[0071]

[0070] This radial length Ip of the projection 8 is, preferably, at least equal to 25 mm and at most equal to 60 mm, more preferably at least equal to 25 mm and at most equal to 50 mm.

[0072]

[0071] Since the circumferential width wv of the void 9 is at least 5.0 mm and at most 15.0 mm, and the degree of circumferential overlap between two circumferentially adjacent projections 8 is at least 4% and at most 15% of the circumferential width wp of the projection 8, it is possible to improve the endurance performance while maintaining a reasonable level of comfort performance.

[0073]

[0072] If this circumferential width wv of the void 9 is less than 5.0 mm and / or if the degree of circumferential overlap between two circumferentially adjacent projections 8 is greater than 15% of the circumferential width wp of the projection 8, there is a risk that an increase in the stiffness of the sidewall 6 becomes impossible to ignore, this giving rise to a degradation of the comfort performance. If this circumferential width wv of the void 9 is greater than 15.0 mm and / or if the degree of circumferential overlap between two circumferentially adjacent projections 8 is less than 4% of the circumferential width wp of the projection 8, there is a risk that an ability to prevent propagation by means of the projection 8 decreases, so that there would be no improvement in the endurance performance.

[0074]

[0073] The circumferential width wv of the void 9 is an interval where radial lines join circumferential ends of two adjacent projections 8 on an imaginary line spaced radially inward from the outer axial end of the tread by the radial distance D. The circumferential width wp of the projection 8 is an interval where radial lines join the two circumferential ends of the projection 8 measured on the imaginary line spaced radially inward from the outer axial end of the tread by the radial distance D. The radial length Ip of the projection 8 is an interval where circumferential lines join the two radial ends of the projection 8.

[0075]

[0074] The projection 8 may have any shape which includes a portion substantially parallel to the respective one of the two outer axial ends of the tread 2 so as to completely intersect the imaginary extension VEL of at least one of the plurality of lateral grooves 3 and possible to create voids 9 between two circumferentially adjacent projections 8.

[0076]

[0075] The shape of the projection 8 may vary from one projection 8 to another projection 8.

[0077]

[0076] The upper face 81 of the projection 8 may have an additional distinctive design or part on its surface, for example lines, characters, holes of any shape, a small projection of any shape not exceeding the maximum height hpm, etc. to make its appearance more attractive.

[0078]

[0077] A tire 21 according to a second embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a schematic plan view of a tire according to a second embodiment of the present invention. The construction of this second embodiment is similar to that of the first embodiment except for the structure illustrated in Fig. 4, and the description will therefore be made with reference to Fig. 4.

[0079]

[0078] As illustrated in Fig. 4, a tire 21 is a tire 21 for a rolling assembly comprising a rim and a tire, comprising a tread 22 intended to come into contact with the ground during rolling via a contact face 225 and having two outer axial ends, the tread 22 comprising a plurality of lateral grooves 23 opening onto both the contact face 225 and one of the two outer axial ends of the tread 22 and extending generally in the axial direction of the tire 21, the tread 22 being connected, via two sidewalls 26, to two bead regions (not shown) intended to be fitted onto the rim (not shown). At least one sidewall 26 comprises, on its outer surface, a series of projections 28 alternating circumferentially with voids 29.

[0080]

[0079] As illustrated in Fig. 4, each of the projections 28 is spaced radially inward from the outer axial end of the tread 22, each of the projections 28 has an upper face 281 spaced from the surface of the sidewall 26, at least three side faces 282 extend from the surface of the sidewall 26 to the upper face 281, one of the at least three side faces 282 located radially closest to the tread 22 extends substantially parallel to the respective one of the two outer axial ends of the tread 22.

[0081]

[0080] As illustrated in Fig. 4, the side face 282 of the projection 28 located radially closest to the tread 22 extending substantially parallel to the respective one of the two outer axial ends of the tread 22 is located so as to completely intersect an imaginary extension VEL (not illustrated) of at least one of the plurality of lateral grooves 23, and the side faces 282 of circumferentially adjacent projections 28 forming the void 29 have an overlap in the radial direction.

[0082]

[0081] As illustrated in Fig. 4, each of the projections 28 includes an extension portion 83 extending radially inwardly from the radially inwardly oriented side face 282, made to form an integral part of the projection 28.

[0083]

[0082] Since the projection 28 has an extension portion 83 extending radially inwardly from the radially inwardly oriented side face 282, it is possible to produce an aesthetically attractive design since the extension portion 83 gives an original appearance to the projection 8.

[0084]

[0083] The invention is not limited to the examples described and shown and various modifications may be made without departing from its scope. In particular, the invention may be combined with various constructions known in the art.

[0085]

[0084] Fig. 5 is a schematic plan view of a tire according to the prior art. In this Fig. 5, a tire 101 for a rolling assembly, comprising a rim and a tire, comprises a tread 102 intended to come into contact with the ground during rolling by means of a contact face 1025 and having two outer axial ends, the tread 102 comprising a plurality of lateral grooves 103 opening both on the contact face 1025 and one of the two outer axial ends of the tread 102 and extending generally in the axial direction of the tire 101, the tread 102 being connected, by means of two sidewalls 106, to two bead regions (not shown) intended to be fitted on the rim (not shown). At least one flank 106 comprises, on its outer surface, a series of projections 108 alternating circumferentially with voids 109.Each of the projections 108 is spaced radially inward from the outer axial end of the tread 102, each of the projections 108 has an upper face 1081 spaced from the surface of the sidewall 106, at least three side faces 1082 extend from the surface of the sidewall 106 to the upper face 1081, one of the at least three side faces 1082 located radially closest to the tread 102 extends substantially parallel to the respective one of the two outer axial ends of the tread 102. Each of the projections 108 has an extension portion 1083 extending radially inward from the radially inwardly oriented side face 1082, made to be an integral part of the projection 108.The lateral face 1082 of the projection 108 located radially closest to the tread 102 extending substantially parallel to the respective one of the two outer axial ends of the tread 102 is not located so as to completely intersect an imaginary extension VEL (not shown) of at least one of the plurality of lateral grooves 103, and the lateral faces 1082 of circumferentially adjacent projections 108 forming the void 109 do not have an overlap in the radial direction.

[0086]

[0085] In order to confirm the effect of the present invention, a computer simulation (finite element analysis) was carried out using commercially available software, and a 3D graphical representation was created. Two types of tire model / graphical representation serving as examples to which the present invention was applied and another type of tire model / graphical representation serving as a reference were prepared.

[0087]

[0086] Example 1 was a model / graphic representation of a tire according to the first embodiment described above and having a maximum height hpx of 2.0 mm. Example 2 was also a model / graphic representation of a tire according to the first embodiment described above and having a maximum height hpx of 6.0 mm. The Reference was a model / graphic representation of a tire according to the prior art and having a maximum height hpx of 0.6 mm.

[0088]

[0087] Endurance tests:

[0089] A force was applied to the tire model and stresses on the sidewall containing the protrusions were simulated. The results are shown in Table 1. In this Table 1, the results are represented by an index of 100 for the Reference, the smaller the number, the better the performance. Furthermore, a difference of at most 10% can be considered as an equivalence with regard to comfort performance.

[0090]

[0088] Aesthetic quality tests:

[0091] The created graphical representations were observed by several people including a highly qualified expert to determine whether a flank with the protrusions had a subjectively attractive appearance. The results are also shown in Table 1. In Table 1, the results are represented by “O” if the appearance is attractive and by “©” if the appearance is more attractive, compared to the Reference.

[0092] [Table 1]

[0093] As can be seen from Table 1, the Examples exhibit improved endurance performance, with an aesthetically appealing design, while maintaining a reasonable level of comfort performance, which cannot be achieved with prior art tires.

[0094]

[0089] List of reference signs:

[0095] 1, 21 pneumatic

[0096] 2, 22 tread

[0097] 25, 225 contact face

[0098] 3, 23 lateral groove

[0099] 6, 26 flank

[0100] 8. 28 projection

[0101] 81, 281 upper face

[0102] 82, 282 side face

[0103] 83 extension part

[0104] 9. 29 empty

Claims

CLAIMS 1. A tire (1) for a rolling assembly comprising a rim and a tire, the tire (1) comprising a tread (2) intended to come into contact with the ground during rolling via a contact face (25) and having two outer axial ends, the tread (2) comprising a plurality of lateral grooves (3) of width W opening onto both the contact face (25) and one of the two outer axial ends of the tread (2) and extending generally in the axial direction of the tire (1), the tread (2) being connected, via two sidewalls (6), to two bead regions intended to be fitted onto the rim, at least one sidewall (6) comprising, on its outer surface, a series of projections (8) each having a circumferential width wp and a radial length Ip, alternating circumferentially with voids (9) of a circumferential width wv,each of the projections (8) being spaced radially inwardly from the outer axial end of the tread (2) by a radial distance D, each of the projections (8) having an upper face (81) spaced from the surface of the sidewall (6) by a minimum height hpm which is greater than a height of any character and / or design molded on the sidewall (6) other than the projections (8) and by a maximum height hpx, at least three side faces (82) extending from the surface of the sidewall (6) to the upper face (81), one of the at least three side faces (82) located radially closest to the tread (2) extending substantially parallel to the respective one of the two outer axial ends of the tread (2), an imaginary straight line indicating a center of the void (9) being inclined at an angle A with respect to the radial direction,the tire being characterized in that the lateral face (82) of the projection (8) located radially closest to the tread (2) extending substantially parallel to the respective one of the two outer axial ends of the tread (2) is located so as to completely intersect an imaginary extension VEL of at least one of the plurality of lateral grooves (3), in that the lateral faces (82) of circumferentially adjacent projections (8) forming the void (9) have an overlap in the radial direction, and in that the circumferential width wp is at least equal to 150% of the width W of the corresponding lateral groove (3) and at most equal to 110 mm., 2. Tire according to the preceding claim, in which the maximum height hpx of the projection (8) is between 1.0 mm and 8.0 mm inclusive.

3. A tire according to any preceding claim, wherein the angle A of the imaginary straight line indicating the center of the void (9) is between 15° and 75° inclusive.

4. A tire according to any one of the preceding claims, wherein the radial distance D is at least equal to 2.0 mm and at most equal to 7.0 mm.

5. A tire according to any one of the preceding claims, in which the radial length Ip of the projection (8) is at least equal to 20 mm and at most equal to 70 mm.

6. A tire according to any preceding claim, wherein the circumferential width wv of the void (9) is at least 5.0 mm and at most 15.0 mm, and wherein a degree of circumferential overlap between two circumferentially adjacent projections (8) is at least 4% and at most 15% of the circumferential width wp of the projection (8).

7. A tire according to any preceding claim, wherein the projection (8) comprises an extension portion (83) extending radially inward from the radially inwardly oriented side face (82).

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