Tire

Abstract

To provide a tire capable of improving life performance while maintaining visibility of a mark part.SOLUTION: In a tire 1, a raised part 10 raised outward in a tire axial direction from a reference surface 3s is provided in at least one of a pair of side wall parts 3. The raised part 10 extends continuously in a tire circumferential direction in an annular shape. The raised part 10 comprises a tire maximum width position. In the raised part 10, there is formed a mark part 13 comprising a plurality of characters recessed inward in the tire axial direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a tire. [Background technology]

[0002] The following Patent Document 1 describes a tire having a marking portion having one or more marks formed on the sidewall portion. The marking portion has a base portion that protrudes from the surface of the sidewall portion at a certain height. Such a tire is said to improve the visibility of the mark. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-167067 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for improving the life performance of tires such as those described above, particularly tires for commercial vehicles used under high loads, while maintaining the visibility of the markings.

[0005] The present invention has been devised in view of the above problems, and has as its main object to provide a tire that can improve the life performance while maintaining the visibility of the marking portion. [Means for solving the problem]

[0006] The tire includes a pair of sidewall portions, at least one of which is provided with a raised portion that protrudes from a reference plane outward in the tire axial direction, the raised portion extending continuously in a ring shape in the circumferential direction of the tire, the raised portion defining the maximum width position of the tire, and a marking portion including a plurality of letters recessed inward in the tire axial direction is formed on the raised portion. Effect of the Invention

[0007] By employing the above-mentioned configuration, the tire of the present invention can improve the life performance while maintaining the visibility of the marking portion. [Brief description of the drawings]

[0008] [Figure 1] 1 is a tire meridian cross-sectional view of the right half of a tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of the side of a tire. [Diagram 3] FIG. 2 is a partial perspective cross-sectional view of a tire. [Figure 4] FIG. 2 is an enlarged view of FIG. [Diagram 5] 4(A) is an enlarged view of the mark portion in FIG. 3, and (B) is a cross-sectional view taken along line AA in (A). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings include exaggerated expressions and expressions different from the dimensional ratio of the actual structure in order to facilitate understanding of the present invention. In addition, when there are multiple embodiments, the same or common elements are given the same reference numerals throughout the specification, and duplicated explanations are omitted.

[0010] Fig. 1 is a tire meridian cross-sectional view of the right half including the tire rotation axis (not shown) of a tire 1 showing one embodiment of the present invention. Fig. 1 shows a pneumatic tire for passenger cars, more specifically, a tire for commercial cars expected to be used under relatively high loads, as a preferred embodiment. However, the present invention may also be applied to pneumatic tires for light trucks and heavy loads, and non-pneumatic tires that are not filled with pressurized air inside the tire.

[0011] In this specification, unless otherwise specified, the dimensions of each part of the tire 1 are values ​​measured in a normal state. In the case of a pneumatic tire, the "normal state" refers to an unloaded state in which the tire 1 is mounted on a normal rim (not shown) and inflated to a normal internal pressure.

[0012] A "genuine rim" is a rim that is defined for each tire by a standard system that includes the standard on which tire 1 is based, such as a "standard rim" in the case of JATMA, a "Design Rim" in the case of TRA, and a "Measuring Rim" in the case of ETRTO.

[0013] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system including the standard on which tire 1 is based, and is the "maximum air pressure" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITSAT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "INFLATION PRESSURE" in the case of ETRTO.

[0014] The tire 1 includes a pair of sidewall portions 3 (one of the sidewall portions 3 is shown in FIG. 1). The tire 1 further includes a pair of bead portions 4 (one of the bead portions 4 is shown in FIG. 1) located on the radially inner side of each of the pair of sidewall portions 3, and a tread portion 2 connecting the pair of sidewall portions 3 to each other.

[0015] Fig. 2 is an enlarged view of a side surface of the tire 1. Fig. 3 is a perspective cross-sectional view of the tire 1. As shown in Figs. 1 to 3, at least one of the pair of sidewall portions 3 is provided with a raised portion 10 that protrudes from a reference plane 3s outward in the tire axial direction. In the tire 1 of this embodiment, the raised portions 10 are provided on both sidewall portions 3. Note that the tire 1 may be provided with the raised portion 10 on only one of the sidewall portions 3.

[0016] The raised portion 10 extends continuously in a ring shape in the tire circumferential direction. Such raised portion 10 continuously protects the sidewall portion 3 in the tire circumferential direction. The raised portion 10 also constitutes the tire maximum width position M. The vicinity of the tire maximum width position M is the area most likely to come into contact with curbs and the like protruding from the road surface. Therefore, the raised portion 10 constituting the tire maximum width position M can effectively suppress damage to the carcass ply (not shown) and the like due to contact with curbs, thereby improving protection and ultimately life performance. In this specification, the "tire maximum width position M" is the position at which the reference surface 3s protrudes furthest outward in the tire axial direction.

[0017] The raised portion 10 is formed with a marking portion 13 including a plurality of characters recessed inward in the tire axial direction. Such a marking portion 13 can maintain high visibility even when the raised portion 10 is worn away by, for example, a curbstone or the like. In addition, the marking portion 13 reduces the rubber volume of the raised portion 10, so that the heat generation of the sidewall portion 3 during driving can be suppressed, and the durability of the tire 1 and, in turn, the life performance can be improved. In a tire 1 that is excessively heated, the rubber of the sidewall portion 3 deteriorates, and the steering stability deteriorates. The "characters" include European letters, numbers, and symbols, and represent, for example, the tire manufacturer name, brand name, size, etc. The marking portion 13 is formed, for example, only from a plurality of characters. In addition, the marking portion 13 defines a recessed space 15. The recessed space 15 constitutes the characters.

[0018] The tread portion 2 of the present embodiment is provided with a plurality of shoulder blocks 5 including the tread end Te, and shoulder lateral grooves 6 adjacent to the shoulder blocks 5 and extending from the inside to the outside of the tread end Te in the axial direction of the tire.

[0019] In the case of a pneumatic tire, the tread edge Te is the axially outermost position of the tire 1 in a normal load state where the tire 1 touches a flat surface. The normal load state is a state where the tire 1 in the normal state is loaded with a normal load and is in contact with the flat surface at a camber angle of 0°. The "normal load" is a load determined for each tire by each standard in a standard system including the standard on which the tire 1 is based, and is "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO.

[0020] The sidewall portion 3 of this embodiment includes an annular portion 9 that extends continuously in the tire circumferential direction around the tire rotation axis. The annular portion 9 is formed, for example, by protruding outward in the tire axial direction from the reference plane 3s. The annular portion 9 is located radially outward of the tire maximum width position M. The shoulder lateral grooves 6 are connected to the annular portion 9 of this embodiment. Furthermore, the radial separation distance Hf between the annular portion 9 and the bead base line BL is preferably 70% or more of the tire cross-sectional height H, more preferably 75% or more, more preferably 90% or less, and even more preferably 85% or less. The "tire cross-sectional height H" is the radial distance from the bead base line BL to the radially outermost position of the tire 1. The "bead base line BL" is a tire axial line passing through the rim diameter position.

[0021] The reference surface 3s is formed by a hidden surface located axially inward from the surface of the sidewall portion 3 by partial irregularities such as the annular portion 9, the raised portion 10, and a protective rib for preventing rim separation, and an outer surface which is a part of the surface and smoothly connects to the hidden surface. The reference surface 3s in this embodiment is formed so as to smoothly connect the groove bottom 6s of the shoulder lateral groove 6 and the outer surface 4s of the bead portion 4 in the tire meridian cross section.

[0022] The raised portion 10 is formed, for example, so that the length La in the tire radial direction is the same continuously in the tire circumferential direction. Note that the length La of the raised portion 10 may vary in the tire circumferential direction (not shown).

[0023] In a typical tire 1, a curb or the like that protrudes from the road surface is more likely to come into contact with an area that is radially outward from the tire maximum width position M than with an area that is radially inward from the tire maximum width position M. For this reason, the radially intermediate position 10p of the raised portion 10 of this embodiment is located radially outward from the tire maximum width position M. This makes it possible to more effectively prevent damage to the tire 1.

[0024] Fig. 4 is an enlarged view of the raised portion 10 in Fig. 1. As shown in Fig. 4, the raised portion 10 includes an outer edge 10e in the tire radial direction, an inner edge 10i in the tire radial direction, and an intermediate portion 10c in the tire radial direction. The raised portion 10 also includes a protruding height in the tire axial direction from the reference plane 3s. The "protruding height" is the length in the normal direction to the reference plane 3s in the tire meridian cross section. The intermediate portion 10c is between the outer edge 10e and the inner edge 10i, and includes an intermediate position 10p (shown in Fig. 1) between the outer edge 10e and the inner edge 10i.

[0025] The raised portion 10 includes, for example, a wall surface 11 extending from the reference surface 3s in the tire axial direction, and an outward surface 12 connected to the wall surface 11 and facing outward in the tire axial direction. In this embodiment, the wall surface 11 extends continuously in the tire circumferential direction. The outer edge 10e and the inner edge 10i are formed at the intersection of the wall surface 11 and the outward surface 12.

[0026] In the tire meridian cross section, the outward surface 12 of this embodiment is formed in an arc shape. Such an outward surface 12 can reduce damage by dispersing the impact caused by contact with a curb in multiple directions. Note that the outward surface 12 may be formed in a tapered shape toward the outside in the tire axial direction, for example, in the tire meridian cross section.

[0027] The protruding height Hc of the intermediate portion 10c of the raised portion 10 is formed to be greater than the protruding heights He and Hi at the outer edge 10e and inner edge 10i, for example. This reduces the tire volume on the outer edge 10e side and the inner edge 10i side to suppress heat generation during running, and enhances protection in the intermediate portion 10c. In this way, the protruding height of the raised portion 10 of this embodiment decreases continuously from the intermediate portion 10c toward the outer edge 10e and inner edge 10i.

[0028] In order to effectively exert the above-mentioned action, the protruding height Hc of the middle portion 10c is preferably 4 times or less than the protruding heights He, Hi of the outer edge 10e and the inner edge 10i. In order to improve the life performance while maintaining the visibility of the marking portion 13, the protruding height Hc of the middle portion 10c is more preferably 1.1 times or more, and more preferably 2 times or less, of the protruding heights He, Hi of the outer edge 10e and the inner edge 10i. Although not particularly limited, the protruding height Hc of the middle portion 10c is preferably, for example, 0.5 to 5 mm.

[0029] Moreover, the protruding height Hc of the intermediate portion 10c is preferably 5% or more of the tire thickness Ht passing through the intermediate portion 10c, more preferably 10% or more, more preferably 50% or less, and even more preferably 35% or less. Since the protruding height Hc of the intermediate portion 10c is 5% or more of the tire thickness Ht, the sidewall portion 3 can be effectively protected. Since the protruding height Hc of the intermediate portion 10c is 50% or less of the tire thickness Ht, an excessive increase in mass due to the marking portion 13 can be suppressed. The tire thickness Ht is the length in the normal direction of the tire cavity surface 1b, and is the length between the tire cavity surface 1b and the outward surface 12.

[0030] As shown in Fig. 1, the length La of the raised portion 10 in the tire radial direction is preferably 5% or more of the tire cross-sectional height H (shown in Fig. 1), more preferably 10% or more, and more preferably 30% or less, and even more preferably 25% or less. Since the length L1 of the raised portion 10 is 5% or more of the tire cross-sectional height H, the sidewall portion 3 can be effectively protected from contact with a curb. Since the length La of the raised portion 10 is 30% or less of the tire cross-sectional height H, the rubber volume of the raised portion 10 is prevented from becoming excessively large, and heat generation during running can be suppressed.

[0031] The depth d1 of the marking portion 13 (depth of the recessed space 15) is preferably 30% or more of the protruding height Hc of the middle portion 10c, more preferably 40% or more, more preferably 80% or less, and even more preferably 70% or less. Since the depth d1 of the marking portion 13 is 30% or more of the protruding height Hc of the middle portion 10c, the mass of the tire 1 can be effectively reduced and heat generation during running can be suppressed. Since the depth d1 of the marking portion 13 is 80% or less of the protruding height Hc of the middle portion 10c, excessive reduction in rigidity of the raised portion 10 is suppressed, and damage caused by contact with a curb can be suppressed.

[0032] Fig. 5(A) is an enlarged perspective view of the marking portion 13 in Fig. 2. Fig. 5(B) is a cross-sectional view taken along line AA in (A). As shown in Fig. 5, the recessed space 15 of this embodiment is provided with serrations 20 each having a plurality of ridges 21 arranged side by side. Such serrations 20 have the effect of making the characters appear darker, improving the visibility of the marking portion 13, and suppressing heat generation from the raised portion 10 during running. In this embodiment, each ridge 21 extends in the radial direction of the tire in order to effectively support the load of the tire 1.

[0033] The maximum height Hs of the ridge 21 is desirably 30% or more of the depth d1 (shown in FIG. 4) of the recessed space 15, more desirably 50% or more, more desirably 70% or less, and even more desirably 60% or less. Since the maximum height Hs of the ridge 21 is 40% or more of the depth d1 of the recessed space 15, the effect of absorbing light irradiated into the recessed space 15 is highly exhibited, enhancing the effect of improving the visibility of the marking portion 13. Since the maximum height Hs of the ridge 21 is 70% or less of the depth d1 of the recessed space 15, excessive increase in mass due to the ridge 21 is suppressed.

[0034] The length Lb of the recessed space 15 (the letters) in the tire radial direction is preferably 50% or more of the length La of the raised portion 10 in the tire radial direction, more preferably 70% or more, more preferably 90% or less, and even more preferably 80% or less. Since the length Lb of the recessed space 15 is 50% or more of the length La of the raised portion 10, the symbol portion 13 (the letters) can be clearly recognized. Since the length Lb of the recessed space 15 is 90% or less of the length La of the raised portion 10, the rigidity of the raised portion 10 is maintained, and damage due to contact with a curb can be suppressed.

[0035] As shown in Figs. 1 to 3, one of the pair of sidewall portions 3 in this embodiment is provided with an outer protuberance 16 that protrudes outward in the tire axial direction from the reference plane 3s. In this embodiment, the outer protuberance 16 is located outward in the tire radial direction from the protuberance 10. Such an outer protuberance 16 can further suppress damage caused by contact between a curb and the sidewall portion 3. The outer protuberance 16 and the protuberance 10 are separated by, for example, the reference plane 3s (the outer surface). The outer protuberance 16 in this embodiment is located inward in the tire radial direction from the annular portion 9 and is connected to the annular portion 9.

[0036] A plurality of outer ridges 16 are arranged in the tire circumferential direction. Specifically, the outer ridges 16 are formed in a rectangular block shape in a side view of the tire 1. The outer ridges 16, 16 adjacent to each other in the tire circumferential direction are separated by a reference plane 3s (the outer surface). Such outer ridges 16 suppress excessive increase in the mass of the tire 1. In order to achieve a good balance between the effect of suppressing damage caused by the outer ridges 16 and the effect of suppressing heat generation, the length Wc of the outer ridges 16 in the tire circumferential direction is preferably 40% or more of the circumferential pitch P of the outer ridges 16, more preferably 50% or more, more preferably 90% or less, and even more preferably 80% or less. In this specification, the length Wc and the circumferential pitch P of the outer ridges 16 are measured at the outer end 16e of the outer ridges 16 in the tire radial direction.

[0037] The length Lc of the outer raised portion 16 in the tire radial direction is smaller than, for example, the length La of the raised portion 10 in the tire radial direction. This allows the raised portion 10 to effectively prevent damage in the vicinity of the tire's maximum width position M where damage from curbs is most likely to occur. Also, excessive increase in the mass of the tire 1 can be prevented in the vicinity of the inner side in the tire radial direction than the annular portion 9 where damage is relatively unlikely to occur. From this perspective, the length Lc of the outer raised portion 16 is preferably 40% or more of the length La of the raised portion 10, more preferably 45% or more, more preferably 60% or less, and even more preferably 55% or less.

[0038] The protruding height Hb of the outer protruding portion 16 in the tire axial direction from the reference plane 3s is preferably equal to or less than the protruding height Hc of the middle portion 10c. Since the region where the outer protruding portion 16 is provided is less likely to come into contact with a curb than the vicinity of the tire maximum width position M, by setting the protruding height Hb equal to or less than the protruding height Hc, damage caused by the curb in the region can be suppressed, and heat generation can be suppressed to maintain high durability of the tire 1. Although not particularly limited, the protruding height Hb is preferably 30% or more of the protruding height Hc, more preferably 40% or more, more preferably 90% or less, and even more preferably 60% or less.

[0039] In this embodiment, the protruding height Hb of the outer protruding portion 16 is smaller than the protruding height Hd of the annular portion 9 in the tire axial direction. This further maintains high durability of the tire 1. Although not particularly limited, the protruding height Hb is preferably 55% or more of the protruding height Hd, more preferably 60% or more, more preferably 75% or less, and even more preferably 70% or less.

[0040] As shown in FIG. 3, one of the pair of sidewall portions 3 includes a first rubber portion G1 forming the raised portion 10 and a second rubber portion G2 forming the reference surface 3s. The first rubber portion G1 and the second rubber portion G2 are adjacent to each other in the tire axial direction, for example. The second rubber portion G2 forms the inner side of the tire axial direction from the reference surface 3s, and is disposed between the first rubber portion G1 and a carcass ply (not shown). The rubber hardness h1 of the first rubber portion G1 is formed to be larger than the rubber hardness h2 of the second rubber portion G2. The first rubber portion G1, which has a relatively large rubber hardness h1, can suppress damage to the raised portion 10 caused by a curb or the like. The second rubber portion G2, which has a relatively small rubber hardness h2, maintains the basic performance of the tire 1, such as ride comfort, at a high level. Although not particularly limited, the difference (h1-h2) between the rubber hardness h1 of the first rubber portion G1 and the rubber hardness h2 of the second rubber portion G2 is preferably 0.5 or more, more preferably 1 or more, and is preferably 8 or less, and even more preferably 5 or less. In this specification, the rubber hardness is a durometer A hardness measured in an environment of 23°C using a durometer type A based on JIS-K6253.

[0041] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified and carried out in various forms.

[0042] [Note] The present invention includes the following aspects.

[0043] [Invention 1] 1. A tire including a pair of sidewall portions, At least one of the pair of sidewall portions is provided with a raised portion that protrudes from a reference plane toward an outer side in the tire axial direction, The raised portion extends continuously in an annular shape in the tire circumferential direction, The raised portion defines a maximum tire width position, The raised portion has a marking portion including a plurality of characters recessed toward the inside in the tire axial direction. tire. [Invention 2] the raised portion includes an outer edge in a tire radial direction, an inner edge in a tire radial direction, a middle portion in a tire radial direction, and a protruding height in an axial direction of the tire from the reference surface, The tire according to claim 1, wherein the protruding height of the middle portion of the raised portion is greater than the protruding heights at the outer edge and the inner edge. [Invention 3] The tire according to claim 2, wherein the protruding height of the middle portion is four times or less the protruding heights of the outer edge and the inner edge. [Invention 4] The tire according to invention 2 or 3, wherein the protruding height of the intermediate portion is 5% to 50% of the tire thickness passing through the intermediate portion. [Invention 5] The tire according to any one of claims 2 to 4, wherein the depth of the marking portion is 30% to 80% of the protruding height of the middle portion. [Invention 6] The indicia portion defines a recessed space; The tire according to any one of claims 1 to 5, wherein the recessed space is provided with serrations each having a plurality of aligned ridges. [Invention 7] 7. The tire according to claim 6, wherein the maximum height of the ridge is 30% to 70% of the depth of the recessed space. [Invention 8] The tire according to invention 6 or 7, wherein the length of the recessed space in the tire radial direction is 50% to 90% of the length of the raised portion in the tire radial direction. [The present invention 9] The tire according to any one of claims 1 to 8, wherein the length of the raised portion in the tire radial direction is 5% to 30% of the tire cross-sectional height. [The present invention 10] the one of the pair of sidewall portions is provided with an outer protruding portion that protrudes outward in the tire axial direction from the reference surface, 10. The tire according to any one of claims 1 to 9, wherein the outer protuberance is spaced apart radially outward from the protuberance. [The present invention 11] The tire according to claim 10, wherein the outer ridges are arranged in a plurality in the tire circumferential direction. [The present invention 12] the raised portion includes a middle portion in a tire radial direction and a protruding height in an axial direction of the tire from the reference surface, 12. The tire according to claim 10 or 11, wherein a protruding height of the outer protruding portion from the reference plane in the tire axial direction is equal to or less than the protruding height of the intermediate portion. [The present invention 13] The one of the pair of sidewall portions includes a first rubber portion that forms the raised portion and a second rubber portion that forms the reference surface, 13. The tire according to any one of claims 1 to 12, wherein the first rubber portion has a rubber hardness greater than a rubber hardness of the second rubber portion. [Explanation of symbols]

[0044] 1 Tire 3 Sidewall 3s reference plane 10 Ridges 13 Emblems M Maximum tire width position

Claims

1. 1. A tire including a pair of sidewall portions, At least one of the pair of sidewall portions is provided with a raised portion that protrudes from a reference plane toward an outer side in the tire axial direction, The raised portion extends continuously in an annular shape in the tire circumferential direction, The raised portion defines a maximum tire width position, The raised portion has a marking portion including a plurality of characters recessed toward the inside in the tire axial direction. tire.

2. the raised portion includes an outer edge in a tire radial direction, an inner edge in a tire radial direction, a middle portion in a tire radial direction, and a protruding height in an axial direction of the tire from the reference surface, The tire of claim 1 , wherein the intermediate portion of the raised portion has a projection height greater than projection heights at the outer and inner edges.

3. 3. The tire of claim 2, wherein the projection height of the intermediate portion is four times or less than the projection heights at the outer edge and the inner edge.

4. The tire of claim 2 , wherein said projection height of said intermediate portion is between 5% and 50% of the tire thickness through said intermediate portion.

5. 3. The tire according to claim 2, wherein a depth of the marking portion is 30% to 80% of the protruding height of the intermediate portion.

6. The indicia portion defines a recessed space; The tire according to claim 1 , wherein the recessed space is provided with serrations each having a plurality of aligned ridges.

7. The tire according to claim 6, wherein the maximum height of the ridge is between 30% and 70% of the depth of the recessed space.

8. The tire according to claim 6, wherein a length of the recessed space in the tire radial direction is 50% to 90% of a length of the raised portion in the tire radial direction.

9. 5. The tire according to claim 1, wherein a length of the raised portion in the tire radial direction is 5% to 30% of a tire section height.

10. the one of the pair of sidewall portions is provided with an outer protruding portion that protrudes outward in the tire axial direction from the reference surface, 5. A tire according to claim 1, wherein the outer ridge is spaced radially outward from the ridge.

11. The tire according to claim 10 , wherein the outer ridges are arranged in a plurality in the tire circumferential direction.

12. the raised portion includes a middle portion in a tire radial direction and a protruding height in an axial direction of the tire from the reference surface, The tire according to claim 10 , wherein a protruding height of the outer protruding portion from the reference plane in the tire axial direction is equal to or smaller than the protruding height of the intermediate portion.

13. the one of the pair of sidewall portions includes a first rubber portion that forms the raised portion and a second rubber portion that forms the reference surface, The tire according to claim 1 , wherein a rubber hardness of the first rubber portion is greater than a rubber hardness of the second rubber portion.

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