Pneumatic tire

Abstract

To provide a pneumatic tire allowing appearance performance of a first sidewall part to be improved.SOLUTION: There is provided a pneumatic tire having a side block 10 formed at a first sidewall part 3A. An outer end 10e of the side block 10 is located within a region A1. The side block 10 includes: a pair of first parts 11 each protruding to a first protrusion height H1; and a second part 12 protruding to a second protrusion height H2 and located between the first parts 11. The second part 12 includes a second top surface 28. The first parts 11 each include a first top surface 21, an outer wall surface 22, and an inner wall surface 23. At a block outer position Be and at a block inner position, a sum of lengths La, Lb of the first top surfaces 21 and a length Lc of the second top surface 28 is 20% or more and 75% or less of a length LA of the side block 10 in a tire circumferential direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 below describes a pneumatic tire having a first buttress portion, in which a plurality of protectors are formed, protruding axially outward. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-054637 Summary of the Invention [Problem to be solved by the invention]

[0004] A known method for manufacturing a pneumatic tire is to vulcanize an unvulcanized pneumatic tire in a vulcanization mold. In a pneumatic tire provided with the above-described protector, a large number of bare holes are likely to occur in the first buttress portion, for example, due to non-discharge of air during the vulcanization process, and there is room for improvement in the appearance performance of the first buttress portion.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a pneumatic tire that can improve the appearance performance of the first sidewall portion. [Means for solving the problem]

[0006] A pneumatic tire including a tread portion, a first sidewall portion connected to the tread portion, and a belt layer embedded in the tread portion and extending in the tire axial direction, wherein at least one side block is formed in the first sidewall portion, protruding outward in the tire axial direction from a sidewall reference plane, the side block including an outer end in the tire radial direction, and in a tire meridian cross section, the outer end is located within a region of 30 mm in the tire radial direction centered on an intersection point between an imaginary extension line extending the belt layer toward the first sidewall portion and an outer surface of the first sidewall portion, the side block having a pair of first portions protruding from the sidewall reference plane at a first protrusion height and extending in the tire radial direction, and a pair of first portions protruding from the sidewall reference plane at a second protrusion height smaller than the first protrusion height and extending in the tire radial direction. and a second portion located between the first and second top surfaces, the second portion including a second top surface parallel to the sidewall reference plane, and each of the pair of first portions including a first top surface parallel to the sidewall reference plane, an outer wall surface connecting the first top surface and the sidewall reference plane, and an inner wall surface connecting the first top surface and the second top surface, wherein in a cross section of the side block cut in a direction normal to the sidewall reference plane along the tire circumferential direction at a block outer position spaced 5 mm radially inward from the outer end of the side block and at a block inner position spaced 15 mm radially outward from the inner end of the side block, the sum of the length of the pair of first top surfaces and the length of the second top surface is 20% or more and 75% or less of the tire circumferential length of the side block on the sidewall reference plane. [Effects of the Invention]

[0007] By employing the above-described configuration, the pneumatic tire of the present invention can improve the appearance performance of the first sidewall portion. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a tire meridian cross-sectional view of a pneumatic tire according to one embodiment of the present invention. [Figure 2] (A) is a front view of a side block, and (B) is a cross-sectional view taken along line AA of (A). [Figure 3] FIG. 2 is an enlarged view of the first sidewall portion of FIG. [Figure 4] FIG. 4 is an enlarged front view of the first sidewall portion. [Figure 5] FIG. 5 is an enlarged schematic view of FIG. [Figure 6] FIG. [Figure 7] 5A is a cross-sectional view taken along line BB in FIG. 5, (B) is a cross-sectional view taken along line CC in FIG. 5, and (C) is a cross-sectional view taken along line DD in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings include exaggerated representations and representations that differ from the dimensional ratios of the actual structure to facilitate understanding of the present invention. Furthermore, when there are multiple embodiments, the same or common elements are designated by the same reference numerals throughout the specification, and redundant explanations will be omitted.

[0010] FIG. 1 is a tire meridian cross-sectional view including a tire rotation axis (not shown) of a pneumatic tire (hereinafter sometimes referred to as "tire") 1 according to one embodiment of the present invention. FIG. 1 shows a tire for light trucks as a preferred embodiment. However, the present invention may also be applied to tires for passenger cars and heavy loads. FIG. 1 shows tire 1 in a normal state.

[0011] In the case of a pneumatic tire for which various standards are established, the "normal state" refers to a state in which the tire is mounted on a normal rim, adjusted to a normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established, the normal state refers to a standard use state according to the intended use of the tire, in which the tire is not mounted on a vehicle and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal state. Furthermore, for components that cannot be measured in the normal state (for example, the internal materials of the tire 1), the values ​​are measured by placing the tire 1 in a state as close as possible to the normal state.

[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" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO.

[0013] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which tire 1 is based. In the case of JATMA, it is the "maximum air pressure," in the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS SAT VARIOUSCOLD INFLATION PRESSURES," and in the case of ETRTO, it is the "INFLATION PRESSURE."

[0014] The tire 1 includes a tread portion 2 and a first sidewall portion 3A connected to the tread portion 2. The tire 1 also includes a belt layer 7 embedded in the tread portion 2 and extending in the tire axial direction.

[0015] At least one side block 10 is formed in the first sidewall portion 3A, protruding axially outward from the sidewall reference plane 3k. The side block 10 provides basic aesthetic design to the first sidewall portion 3A.

[0016] Fig. 2(A) is an enlarged front view of the first sidewall portion 3A. Fig. 2(A) shows one side block 10. As shown in Figs. 1 and 2(A), the side block 10 includes a radially outer end 10e and a radially inner end 10i. The side block 10 also includes a pair of first portions 11 and a second portion 12 located between the pair of first portions 11.

[0017] FIG. 2(B) is a cross-sectional view taken along line AA in FIG. 2(A). FIG. 2(B) shows a cross-section of the side block 10 taken along the tire circumferential direction, normal to the sidewall reference plane 3k. As shown in FIG. 2, each first portion 11 protrudes from the sidewall reference plane 3k at a first protrusion height H1 and extends in the tire radial direction. The second portion 12 protrudes from the sidewall reference plane 3k at a second protrusion height H2 that is smaller than the first protrusion height H1. The second portion 12 includes a second top surface 28 that is parallel to the sidewall reference plane 3k. In this specification, the term "parallel to the sidewall reference plane 3k" refers to a state that allows for unavoidable errors in rubber products such as tires, and includes, for example, a state that can be visually recognized as being parallel to the sidewall reference plane 3k. When the first protrusion height H1 or the second protrusion height H2 varies in the tire radial direction, the first protrusion height H1 and the second protrusion height H2 are determined at the same position in the tire radial direction.

[0018] Each first portion 11 includes a first top surface 21 parallel to the sidewall reference surface 3k, an outer wall surface 22 connecting the first top surface 21 and the sidewall reference surface 3k, and an inner wall surface 23 connecting the first top surface 21 and the second top surface 28.

[0019] FIG. 3 is an enlarged view of the first sidewall portion 3A in FIG. 1. As shown in FIGS. 1 to 3, in the tire meridian cross section, the first sidewall portion 3A has an area A1 of 30 mm in the tire radial direction centered on an intersection point K1. The intersection point K1 is the point where an imaginary extension line 7i extending the belt layer 7 toward the first sidewall portion 3A intersects with the outer surface 3s of the first sidewall portion 3A. The area A1 is a portion where multiple components constituting the tire 1 are overlapped, and where air tends to collect in each of the components during vulcanization molding of the tire 1 (hereinafter referred to as "tire vulcanization"). The components include the belt layer 7, a sidewall rubber 3G, a tread rubber 2G, etc., which will be described later.

[0020] The outer end 10e is located within the region A1. This allows air within the components and air between the components to be collected in the vulcanization mold (not shown) that forms the side block 10 during tire vulcanization, thereby reducing the occurrence of bare spots. Furthermore, air is easily collected in the vulcanization mold that contacts the first top surface 21 and the second top surface 28, preventing air from flowing into other areas (e.g., the vulcanization mold that contacts the sidewall reference surface 3k, etc.). Furthermore, during tire vulcanization, the outer wall surface 22 and the inner wall surface 23 are areas where the contact pressure with the vulcanization mold that contacts the outer wall surface 22 and the inner wall surface 23 is relatively small, allowing for smooth airflow. Therefore, the side block 10 can efficiently collect air during tire vulcanization and then discharge the air, improving the appearance of the first sidewall portion 3A.

[0021] As shown in FIG. 2A, the side block 10 includes a block outer position Be and a block inner position Bi. The block outer position Be is located 5 mm radially inward from the outer end 10e of the side block 10. The block inner position Bi is located 15 mm radially outward from the inner end 10i of the side block 10. The area between the block outer position Be and the block inner position Bi is the area where air is most likely to collect in each component during tire vulcanization. Furthermore, the area between these positions Be and Bi is highly visible from outside the vehicle when the tire 1 is mounted on the vehicle, and this position has a significant impact on the appearance performance of the first sidewall portion 3A.

[0022] As shown in FIG. 2(B), between the block outer position Be and the block inner position Bi, the sum (La + Lb + Lc) of the lengths La and Lb of the pair of first top surfaces 21 and the length Lc of the second top surface 28 is set to 20% or more and 75% or less of the length LA of the side block 10. By setting the sum (La + Lb + Lc) to 70% or less of the length LA of the side block 10, air flows more smoothly into the vulcanization mold that contacts the first top surfaces 21 between the block outer position Be and the block inner position Bi during tire vulcanization. This, for example, makes it easier for air from each of the components to be collected in the vulcanization mold that contacts the first top surfaces 21. Furthermore, this collected air is efficiently discharged to the outside of the vulcanization mold, for example, through air exhaust holes (not shown) provided in the vulcanization mold. Furthermore, by making the sum (La+Lb+Lc) 20% or more of the length LA of the side block 10, the aesthetic shape (design) of the side block 10 is improved. Therefore, the tire 1 of the present invention can improve the appearance performance of the first sidewall portion 3A. In this embodiment, the sum (La+Lb+Lc) is 20% or more and 75% or less of the length LA of the side block 10 at any position between the block outer position Be and the block inner position Bi. The length LA of the side block 10 is the length of the side block 10 above the sidewall reference plane 3k in the tire circumferential direction.

[0023] In order to more effectively exert the above-mentioned effect, the sum (La+Lb+Lc) is preferably 35% or more and 50% or less of the length LA.

[0024] The difference (H1-H2) between the first protrusion height H1 and the second protrusion height H2 is preferably 0.5 to 5.0 mm. When the difference (H1-H2) is 0.5 mm or more, the air flow during tire vulcanization is further improved, and bare spots can be further reduced. From this perspective, the difference (H1-H2) is more preferably 1.0 mm or more, and even more preferably 1.5 mm or more. When the difference (H1-H2) is 5.0 mm or less, the side blocks 10 do not appear to protrude excessively, thereby further improving the appearance of the first sidewall portion 3A. Furthermore, since the difference (H1-H2) is 5.0 mm or less, the rigidity of the side blocks 10 is maintained, and its durability can be improved. From the viewpoint of further reducing the occurrence of bare spots and reducing the appearance of excessive protrusion of the side blocks 10, the difference (H1-H2) is more preferably 4.0 mm or less, and even more preferably 3.0 mm or less, in combination with any lower limit value. For example, the difference (H1-H2) is more preferably 1.0 to 4.0 mm, and even more preferably 1.5 to 3.0 mm.

[0025] As shown in FIG. 1, the tire 1 includes, for example, a first bead portion 4A, a second sidewall portion 3B, and a second bead portion 4B. The first bead portion 4A is connected to the first sidewall portion 3A. The second sidewall portion 3B is connected to the tread portion 2 on the opposite side of the tire axial direction from the first sidewall portion 3A. The second bead portion 4B is connected to the second sidewall portion 3B. In this embodiment, the second sidewall portion 3B has the same shape as the first sidewall portion 3A. The second sidewall portion 3B in this embodiment is provided with side blocks 10. The first bead portion 4A and the second bead portion 4B have the same shape. Therefore, in this specification, description of the second sidewall portion 3B and the second bead portion 4B will be omitted. The second sidewall portion 3B may have a shape different from that of the first sidewall portion 3A.

[0026] The first sidewall portion 3A or the first bead portion 4A is provided with a marking portion K that is spaced apart from the side blocks 10 radially inward. In this way, in the tire 1 of this embodiment, the marking portion K and the side blocks 10 are spaced apart in the tire radial direction. This allows the basic aesthetic design provided by the side blocks 10 to be maintained at a high level. The marking portion K is a concave or convex portion provided on the outer surface 3s of the first sidewall portion 3A or the outer surface 4s of the first bead portion 4A, and consists of letters, figures, symbols, etc., and represents information such as tire size and manufacturing year and week.

[0027] The belt layer 7 is formed by stacking a plurality of belt plies in the tire radial direction. In this embodiment, the plurality of belt plies is formed by two belt plies: an outer belt ply 7A located outermost in the tire radial direction, and an inner belt ply 7B located inside the outer belt ply 7A in the tire radial direction. The plurality of belt plies is not limited to two.

[0028] Each of the outer belt ply 7A and the inner belt ply 7B includes a plurality of belt cords arranged at an angle of 15 to 45 degrees with respect to the tire circumferential direction and a topping rubber covering the cords (not shown). The belt cords may be, for example, steel cords or organic fiber cords such as aramid or rayon.

[0029] The inner belt ply 7B has, for example, a longer length L1 in the tire axial direction than the outer belt ply 7A. Both outer ends 7e in the tire axial direction of the inner belt ply 7B are located axially inward of the tread end Te.

[0030] 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 contacts 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 the "maximum load capacity" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "LOAD CAPACITY" in the case of ETRTO.

[0031] The tire 1 further includes a carcass 6 extending in a toroidal shape between the first bead portion 4A and the second bead portion 4B, a tread rubber 2G arranged in the tread portion 2, and a sidewall rubber 3G arranged in the first sidewall portion 3A.

[0032] The carcass 6 is composed of, for example, an outer carcass ply 6A and an inner carcass ply 6B disposed further inward in the tire than the outer carcass ply 6A. The outer carcass ply 6A is adjacent to, for example, the inner belt ply 7B on the radially inner side of the tire. Each of the carcass plies 6A, 6B includes, for example, a main body portion 6a extending between the first bead portion 4A and the second bead portion 4B and a turned-up portion 6b continuing to the main body portion 6a. Note that the carcass 6 may be composed of, for example, a single carcass ply.

[0033] Each of the carcass plies 6A, 6B includes a plurality of carcass cords and a topping rubber covering the cords (not shown). The carcass cords are made of organic fiber such as aramid or rayon. The carcass cords are preferably arranged at an angle of 70 to 90 degrees relative to the tire circumferential direction.

[0034] The tread rubber 2G forms, for example, the contact surface 2s of the tread portion 2 and extends axially outward from the tread edge Te. The sidewall rubber 3G forms, for example, side blocks 10. The boundary surface Bs (shown in FIG. 3) between the tread rubber 2G and the sidewall rubber 3G extends axially outward from the axially outer end of the belt layer 7, for example, the outer end 7e of the inner belt ply 7B, and is connected to the outer surface 3s of the sidewall portion 3 within the region A1. The boundary surface Bs is not limited to extending in the axial direction of the tire. The tread rubber 2G and the sidewall rubber 3G are formed of known rubber materials.

[0035] The tread portion 2 is provided with shoulder lateral grooves 8 extending from the tire equator C side beyond the tread edge Te. The shoulder lateral grooves 8 are arranged side by side in the tire circumferential direction (not shown). The shoulder lateral grooves 8 include, for example, groove bottoms 8s extending inward and outward in the tire axial direction, sandwiching the tread edge Te. In this embodiment, the groove bottoms 8s extend substantially parallel to the contact patch 2s.

[0036] As shown in Fig. 3, in this specification, the sidewall reference surface 3k is the outer surface of the first sidewall portion 3A excluding uneven portions such as spews, bulges, dents, and markings K. The sidewall reference surface 3k may be formed, for example, so as to smoothly connect with the tread edge Te of the tread portion 2. The sidewall reference surface 3k may also be formed, for example, so as to smoothly connect with the groove bottoms 8s of the shoulder lateral grooves 8. The sidewall reference surface 3k is formed, for example, as an arc convex outward in the tire axial direction.

[0037] In this specification, the imaginary extension line 7i is defined by the inner surface of the belt ply located radially innermost in the tire. In this embodiment, the imaginary extension line 7i is defined by the inner surface 7u of the inner belt ply 7B. The imaginary extension line 7i is formed by an arc having the same radius of curvature as the inner surface 7u of the inner belt ply 7B. If the inner surface 7u is not formed by an arc having the same radius of curvature between both outer ends 7e of the inner belt ply 7B, the inner surface 7u is defined by connecting a point 7c (shown in FIG. 1) on the tire equator C and both outer ends 7e in the tire axial direction with arcs Sa having the same radius of curvature.

[0038] FIG. 4 is a front view of the first sidewall portion 3A. As shown in FIG. 4, the first sidewall portion 3A of this embodiment is provided with a plurality of side blocks 10. In this embodiment, the side blocks 10 include a first side block 10A, a second side block 10B, and a third side block 10C. In this embodiment, the outer ends 10e of the first side block 10A, the second side block 10B, and the third side block 10C are arranged at the same position in the tire radial direction. For example, the inner ends 10i of the first side block 10A, the second side block 10B, and the third side block 10C are arranged at different positions in the tire radial direction. Such side blocks 10 add variety to the appearance of the first sidewall portion 3A, improving its appearance performance.

[0039] In the first side block 10A, for example, each of the pair of first portions 11 is formed by a first bent portion 31 having one bent portion 30. In the second side block 10B, for example, one of the pair of first portions 11 is formed by the first bent portion 31, and the other of the pair of first portions 11 is formed by a second bent portion 32 having two bent portions 30. In the third side block 10C, for example, one of the pair of first portions 11 is formed by the first bent portion 31, and the other of the pair of first portions 11 is formed by a linear portion 33 extending linearly. In this embodiment, the linear portion 33 extends parallel to the tire radial direction.

[0040] FIG. 5 is an enlarged schematic view of FIG. 4. As shown in FIG. 5, the first bent portion 31 includes a radial portion 35 extending in the tire radial direction and a first inclined portion 36 inclined at a larger angle relative to the tire radial direction than the radial portion 35. The second bent portion 32 includes the radial portion 35, the first inclined portion 36, and a second inclined portion 37 inclined in the opposite direction relative to the first inclined portion 36 in the tire radial direction. In this embodiment, the radial portion 35 extends parallel to the tire radial direction. The first inclined portion 36 is connected to the radial portion 35 on the inner side in the tire radial direction. The second inclined portion 37 is connected to the first inclined portion 36 on the inner side in the tire radial direction. The first inclined portion 36 and the second inclined portion 37 are inclined at an angle θ of 30 degrees or more relative to the tire radial direction, for example. The side block 10 is not limited to this shape.

[0041] In this embodiment, the second portion 12 of each side block 10 includes an equal-length portion 38 and a tapered portion 39. The equal-length portion 38 is formed to extend the same circumferential length in the tire from the outer end 10e of the side block 10 toward the tire radially inward. The tapered portion 39 is located radially inward of the equal-length portion 38 and is formed to have a circumferential length that decreases toward the inner end 10i of the side block 10. The second portion 12 is not limited to this shape. For convenience, in FIGS. 4 and 5, the outer wall surface 22 and the inner wall surface 23 are each represented by a single line segment.

[0042] 2(B), the outer wall surface 22 is inclined, for example, toward the inner wall surface 23 as it extends outward in the tire axial direction. The inner wall surface 23 is inclined, for example, toward the outer wall surface 22 as it extends outward in the tire axial direction. Such an outer wall surface 22 or inner wall surface 23 further smooths the flow of air within the vulcanization mold that contacts the outer wall surface 22 and the inner wall surface 23 during tire vulcanization, thereby improving the appearance performance of the first sidewall portion 3A.

[0043] To effectively exert the above-mentioned effect, the angle α1 between the inner wall surface 23 and the normal n1 of the second top surface 28 is preferably 15 degrees or more. Considering both the effect of suppressing bare spots and the design of the side block 10, the angle α1 is preferably 20 degrees or more, preferably 60 degrees or less, and more preferably 45 degrees or less. In this embodiment, the angle α1 is the same on both the inside and outside of the second portion 12 in the tire radial direction.

[0044] FIG. 6 is a perspective cross-sectional view of the side block 10. As shown in FIG. 6, the first protrusion height H1 of each of the pair of first portions 11 increases continuously toward the outer side in the tire radial direction. Such first portions 11 facilitate air flow toward the outer end 10e of the side block 10 during tire vulcanization. This improves air discharge efficiency. The first protrusion height H1i at the inner end 10i of the side block 10 is preferably 1 mm or more, more preferably 1.5 mm or more, more preferably 5 mm or less, and even more preferably 3 mm or less. Furthermore, the difference (H1e - H1i) between the first protrusion height H1i at the inner end 10i of the side block 10 and the first protrusion height H1e at the outer end 10e of the side block 10 is preferably 0.5 mm or more. In this embodiment, the first protrusion height H1 of all side blocks 10 increases continuously toward the outer side in the tire radial direction.

[0045] FIG. 7(A) is a cross-sectional view taken along line BB in FIG. 5, FIG. 7(B) is a cross-sectional view taken along line CC in FIG. 5, and FIG. 7(C) is a cross-sectional view taken along line DD in FIG. 5. FIG. 7(B) is a cross-sectional view located radially inward of FIG. 7(A). FIG. 7(C) is a cross-sectional view located radially inward of FIG. 7(B). FIG. 7 is a cross-sectional view of the first portion 11. As shown in FIG. 7, the angle α2 between the outer wall surface 22 and the normal n2 to the sidewall reference plane 3k increases radially inward. Such an outer wall surface 22 facilitates air flow toward the outer end 10e of the side block 10 during tire vulcanization. This improves air discharge efficiency. The angle α2 may be the same continuously between the radially inner end 35i and the radially outer end 35e of the radial portion 35.

[0046] As shown in FIGS. 3 to 5, the first sidewall portion 3A includes a circumferential protrusion 40 that protrudes from the sidewall reference plane 3k at a third protrusion height H3 and extends in the tire circumferential direction. The circumferential protrusion 40 is connected to the outer end 10e of the side block 10. This allows air collected in the vulcanization mold that forms the side block 10 during tire vulcanization to also flow into the vulcanization mold that forms the circumferential protrusion 40, further reducing the number of bare spots. In this embodiment, the circumferential protrusion 40 extends continuously and uninterruptedly in the tire circumferential direction. The circumferential protrusion 40 is not limited to this configuration. For example, multiple circumferential protrusions 40 may be provided at equal intervals in the tire circumferential direction (not shown). In this embodiment, the circumferential protrusion 40 is provided in region A1.

[0047] The third protrusion height H3 of the circumferential protrusion 40 is preferably 1 mm or more, more preferably 2 mm or more, and more preferably 5 mm or less, and even more preferably 4 mm or less. In order to improve the appearance of the first sidewall portion 3A, the third protrusion height H3 is preferably smaller than the first protrusion height H1. The circumferential protrusion 40 having such a third protrusion height H3 exhibits the effect of collecting air in the circumferential protrusion 40 and efficiently discharging it without impairing the appearance.

[0048] As shown in FIG. 5 , the first top surface 21 of this embodiment is provided with at least one spew 45. The spew 45 is plasticized rubber that flows into the air exhaust hole (not shown) provided in the vulcanization mold during tire vulcanization and is formed as thin, whisker-like rubber pieces. The air exhaust hole functions to exhaust air from the mold to the outside during tire vulcanization. In other words, during tire vulcanization of the tire 1 of this embodiment, air from the vulcanization mold is exhausted through the air exhaust hole provided in the vulcanization mold that forms the first top surface 21. As described above, the vulcanization mold that forms the first top surface 21 collects a large amount of air from within each component of the tire 1 and between the components. This allows the tire 1 of this embodiment to have significantly improved appearance performance of the first sidewall portion 3A. Note that the spew 45 includes spew marks and the like that are formed by removing the spew 45. For convenience, the spew is omitted from FIGS. 2 to 4 and 6 .

[0049] The outer diameter d1 of the spew 45 is preferably at least two-thirds the length L2 of the first top surface 21. The air discharge holes formed in such a spew 45 allow air to be discharged more smoothly during tire vulcanization. To maintain the appearance performance of the first sidewall portion 3A, the outer diameter d1 of the spew 45 is preferably less than one time the length L2 of the first top surface 21. In this specification, the length L2 of the first top surface 21 is defined as the length perpendicular to the longitudinal direction of the first top surface 21.

[0050] Although not particularly limited, it is desirable that the spews 45 be arranged at equal intervals along the length of the first top surface 21 in the tire radial direction. In other words, when one spew 45 is provided on the first top surface 21, the spew 45 is desirably provided at the center of the first top surface 21 in the tire radial direction. Furthermore, when two spews 45 are provided on the first top surface 21, the spews 45 are desirably provided at positions that divide the first top surface 21 into thirds in the tire radial direction.

[0051] In the first sidewall portion 3A, it is desirable that the spew 45 is provided, for example, only in the first portion 11 of the side block 10, and not in the second portion 12 or the sidewall reference surface 3k. The spew 45 may be provided, for example, in the circumferential protrusion 40.

[0052] 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 implemented in various ways. [Example]

[0053] Pneumatic tires having the basic structure shown in Figure 1 were prototyped based on the specifications in Table 1. Each test tire was then tested for appearance performance. The common specifications and test methods for each test tire are as follows: Tire size: 285 / 70R17

[0054] <Appearance performance> The outer surface of the first sidewall portion of each test tire mounted on a vehicle was visually and sensorily evaluated by a tester. The results were scored on a scale of 0 to 100. The smaller the score, the better the design of the side block, the less bare areas there were, and the higher the appearance performance. The test results are shown in Table 1.

[0055] [Table 1]

[0056] As a result of the test, it is understood that the tires of the examples have improved appearance performance compared to the tires of the comparative examples.

[0057] [Note] The present invention includes the following aspects. [Invention 1] A tread portion; a first sidewall portion connected to the tread portion; A pneumatic tire including a belt layer embedded in the tread portion and extending in the tire axial direction, At least one side block is formed in the first sidewall portion, protruding from a sidewall reference plane outward in the tire axial direction, the side blocks include radially outer ends of the tire, In the tire meridian cross section, the outer end is located within a region of 30 mm in the tire radial direction, the region being centered on an intersection between an imaginary extension line of the belt layer extended toward the first sidewall portion and an outer surface of the first sidewall portion, The side blocks are a pair of first portions that protrude from the sidewall reference plane at a first protrusion height and extend in the tire radial direction; a second portion that protrudes from the sidewall reference plane at a second protrusion height that is smaller than the first protrusion height and is located between the pair of first portions, the second portion includes a second top surface parallel to the sidewall reference plane, each of the pair of first portions includes a first top surface parallel to the sidewall reference surface, an outer wall surface connecting the first top surface and the sidewall reference surface, and an inner wall surface connecting the first top surface and the second top surface; At a block outer position 5 mm radially inward from the outer end of the side block and at a block inner position 15 mm radially outward from the inner end of the side block, the sum of the lengths of the pair of first top faces and the length of the second top face is 20% or more and 75% or less of the tire circumferential length of the side block on the sidewall reference plane in a cross section obtained by cutting the side block in the tire circumferential direction in a direction normal to the sidewall reference plane. Pneumatic tires. [Invention 2] The pneumatic tire according to Invention 1, wherein inner ends of the pair of first portions in the tire radial direction are connected to each other. [Invention 3] 3. The pneumatic tire according to claim 1 or 2, wherein an angle between the outer wall surface and a normal to the sidewall reference plane increases toward the inside in the tire radial direction. [Invention 4] 4. The pneumatic tire according to any one of claims 1 to 3, wherein the angle between the inner wall surface and the normal to the second top surface is 15 degrees or more. [Invention 5] 5. The pneumatic tire according to any one of claims 1 to 4, wherein the first protruding height of each of the pair of first portions continuously increases outward in the tire radial direction. [Invention 6] The pneumatic tire according to any one of claims 1 to 5, wherein at least one spew is provided on the pair of first top surfaces. [Invention 7] 7. The pneumatic tire according to claim 6, wherein the outer diameter of the spew is at least 2 / 3 times the length of the first top surface. [Invention 8] the first sidewall portion includes a circumferential protrusion that protrudes from the sidewall reference plane at a third protrusion height and extends in the tire circumferential direction, The pneumatic tire according to any one of the first to seventh aspects of the present invention, wherein the circumferential protrusion is formed by connecting the outer ends of the side blocks. [Invention 9] 9. The pneumatic tire according to invention 8, wherein the third protrusion height is 1.0 mm or more. [Invention 10] 10. The pneumatic tire according to any one of claims 1 to 9, wherein the difference between the first protruding height and the second protruding height is 0.5 to 5.0 mm. [Explanation of symbols]

[0058] 1 pneumatic tire 3A First sidewall 3k reference plane 10 Side Block 10e outer edge 11 Part 1 12 Part 2 21 1st top surface 22 Outside wall 23 Inner wall 28 2nd top surface A1 area H1 First protrusion height H2 Second protrusion height K1 intersection Be Block Outer Position Bi block inner position

Claims

1. A tread portion; a first sidewall portion connected to the tread portion; A pneumatic tire including a belt layer embedded in the tread portion and extending in the tire axial direction, At least one side block is formed in the first sidewall portion, protruding from a sidewall reference plane toward an outer side in the tire axial direction, the side blocks include radially outer ends of the tire, In the tire meridian cross section, the outer end is located within a region of 30 mm in the tire radial direction, the region having a center at an intersection between an imaginary extension line of the belt layer extended toward the first sidewall portion and an outer surface of the first sidewall portion, The side blocks are a pair of first portions protruding from the sidewall reference plane at a first protrusion height and extending in the tire radial direction; a second portion that protrudes from the sidewall reference plane at a second protrusion height that is smaller than the first protrusion height and is located between the pair of first portions, the second portion includes a second top surface parallel to the sidewall reference plane, each of the pair of first portions includes a first top surface parallel to the sidewall reference surface, an outer wall surface connecting the first top surface and the sidewall reference surface, and an inner wall surface connecting the first top surface and the second top surface; In a cross section of the side block cut in the tire circumferential direction in a direction normal to the sidewall reference plane at an outer position of the side block 5 mm radially inward from the outer end of the side block and at an inner position of the side block 15 mm radially outward from the inner end of the side block, the sum of the lengths of the pair of first top faces and the second top face is 20% or more and 75% or less of the tire circumferential length of the side block on the sidewall reference plane. Pneumatic tires.

2. The pneumatic tire according to claim 1 , wherein inner ends of the pair of first portions in the tire radial direction are connected to each other.

3. The pneumatic tire according to claim 2 , wherein an angle between the outer wall surface and a normal to the sidewall reference plane increases toward the inside in the tire radial direction.

4. The pneumatic tire according to claim 1 , wherein an angle between the inner wall surface and a normal to the second top surface is equal to or greater than 15 degrees.

5. The pneumatic tire according to claim 1 , wherein the first protruding height of each of the pair of first portions continuously increases outward in the tire radial direction.

6. The pneumatic tire according to claim 1 , wherein at least one spew is provided on the pair of first top surfaces.

7. The pneumatic tire according to claim 6 , wherein the outer diameter of the spew is at least two-thirds the length of the first top surface.

8. the first sidewall portion includes a circumferential protrusion that protrudes from the sidewall reference plane at a third protrusion height and extends in the tire circumferential direction, The pneumatic tire according to claim 1 , wherein the circumferential protrusion is connected to the outer ends of the side blocks.

9. The pneumatic tire according to claim 8 , wherein the third protrusion height is equal to or greater than 1.0 mm.

10. 4. The pneumatic tire according to claim 1, wherein a difference between the first protruding height and the second protruding height is 0.5 to 5.0 mm.

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