Tire

Abstract

To provide a tire capable of suppressing a poor appearance thereof resulting from residual air, while reducing an air resistance of the tire.SOLUTION: The tire has, on a tire side part, fins 9A, 9B extending at an inclination in a tire circumferential direction and a tire radial direction, a serration region 5 formed of a plurality of narrow grooves arranged in parallel, and a smooth region 6A having a smooth surface. The serration region 5 is connected to one lateral faces of the fins 9A, 9B. The smooth region 6A is connected to the other lateral faces of the fins 9A, 9B.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a tire, and more particularly to a tire that can reduce the air resistance of the tire while suppressing poor appearance of the tire caused by residual air. [Background technology]

[0002] In recent years, in order to reduce the air resistance of the tire and improve the fuel efficiency of the tire, a configuration has been adopted in which a plurality of fins that generate turbulence when the tire rolls are provided on the tire side. As an example of such a conventional tire, the technology described in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 008716 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a tire that can reduce the air resistance of the tire while suppressing poor appearance of the tire caused by residual air. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the tire of the present invention is a tire which includes, in a tire side portion, a fin which extends at an angle with respect to the tire circumferential direction and the tire radial direction, a serration region consisting of a plurality of fine grooves arranged in parallel, and a smooth region having a smooth surface, and is characterized in that the serration region is connected to one side of the fin, and the smooth region is connected to the other side of the fin. Effect of the Invention

[0006] The tire according to the present invention has the advantage that (1) the fins generate turbulence when the tire rolls, thereby reducing the air resistance of the tire and improving the fuel efficiency of the tire. Also, (2) because the fins are interposed between the serrated region and the smooth region, the residual air in the smooth region efficiently flows into the serrated region through the fins during vulcanization of the tire. This promotes the flow of residual air from the smooth region to the serrated region. This has the advantage of suppressing vulcanization defects in the smooth region, particularly the occurrence of poor tire appearance due to residual air. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view showing one tire side portion of the tire shown in FIG. [Diagram 3] FIG. 3 is an enlarged view of the fin shown in FIG. [Figure 4] FIG. 4 is a plan view showing the fin shown in FIG. [Diagram 5] FIG. 5 is a side view showing the fin depicted in FIG. [Figure 6] FIG. 6 is a cross-sectional view showing the fin shown in FIG. [Figure 7] FIG. 7 is a side view showing the tire shown in FIG. [Figure 8] FIG. 8 is an enlarged view showing a first main part of the tire shown in FIG. [Figure 9] FIG. 9 is an enlarged view showing a first main part of the tire shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along line A of the serration region shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line B of the connection portion between the serrated region and the smooth region shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line C of the connection portion of the fin, the serration region, and the smooth region shown in FIG. [Figure 13] FIG. 13 is an enlarged view showing a second main portion of the tire shown in FIG. [Figure 14] FIG. 14 is an enlarged view showing a second main portion of the tire shown in FIG. [Figure 15] FIG. 15 is a table showing the results of performance tests of the tire according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiments. The components of the embodiments include those that can be substituted and are obvious substitutes while maintaining the identity of the invention. The multiple modified examples described in the embodiments can be arbitrarily combined within the scope of what is obvious to those skilled in the art.

[0009] [tire] 1 is a cross-sectional view in the tire meridian direction showing a tire 1 according to an embodiment of the present invention. The figure shows a cross-sectional view of one side region in the tire radial direction. In this embodiment, a pneumatic radial tire for passenger cars will be described as an example of a tire.

[0010] In the figure, the tire meridian cross section is defined as a cross section of the tire cut by a plane including the tire rotation axis (not shown). The tire equatorial plane CL is defined as a plane that passes through the midpoint of the tire section width defined by JATMA and is perpendicular to the tire rotation axis. The tire width direction is defined as a direction parallel to the tire rotation axis, and the tire radial direction is defined as a direction perpendicular to the tire rotation axis. Point T is the tire ground contact edge, and point A is the maximum tire width position.

[0011] Additionally, the vehicle width direction inner side and vehicle width direction outer side are defined as the directions relative to the vehicle width direction when the tire is mounted on a vehicle. Additionally, the left and right regions bounded by the tire equatorial plane are defined as the vehicle width direction outer region and the vehicle width direction inner region, respectively. Additionally, the tire is provided with a mounting direction indicator (not shown) that indicates the tire mounting direction on the vehicle. The mounting direction indicator is formed, for example, by a mark or unevenness provided on the sidewall portion of the tire. For example, ECER30 (Article 30 of the Economic Commission for Europe Regulation) requires that a vehicle mounting direction indicator be provided on the sidewall portion that is on the vehicle width direction outer side when mounted on the vehicle.

[0012] The tire 1 has an annular structure centered on the tire rotation axis, and includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, 16, and a pair of rim cushion rubbers 17, 17 (see Figure 1).

[0013] The pair of bead cores 11, 11 are formed by winding one or more steel bead wires in an annular manner in multiple layers, and are embedded in the bead portions to form the cores of the left and right bead portions. The pair of bead fillers 12, 12 are disposed on the outer periphery of the pair of bead cores 11, 11 in the tire radial direction, respectively, to reinforce the bead portions.

[0014] The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass plies stacked together, and is toroidally stretched between the left and right bead cores 11, 11 to form the tire framework. Both ends of the carcass layer 13 are wrapped around and secured to the outside in the tire width direction so as to envelop the bead cores 11 and the bead fillers 12. The carcass ply of the carcass layer 13 is formed by covering multiple carcass cords made of steel or organic fiber material (e.g., aramid, nylon, polyester, rayon, etc.) with coating rubber and rolling them, and has a cord angle (defined as the inclination angle of the carcass cords in the longitudinal direction with respect to the tire circumferential direction) of 80 degrees or more and 100 degrees or less.

[0015] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is disposed by being wound around the outer periphery of the carcass layer 13. The belt plies 141 to 144 each include a pair of cross belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.

[0016] The pair of cross belts 141, 142 are formed by covering a plurality of belt cords made of steel or organic fiber material with coating rubber and rolling them, and have a cord angle (defined as the inclination angle of the belt cords in the longitudinal direction with respect to the tire circumferential direction) of 15 degrees or more and 55 degrees or less in absolute value. The pair of cross belts 141, 142 have cord angles of opposite signs to each other, and are layered with the longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). The pair of cross belts 141, 142 are layered and arranged on the outer side of the carcass layer 13 in the tire radial direction.

[0017] The belt cover 143 and the pair of belt edge covers 144, 144 are configured by covering a belt cover cord made of steel or organic fiber material with coating rubber, and have a cord angle of 0 degrees or more and 10 degrees or less in absolute value. The belt cover 143 and the belt edge cover 144 may be, for example, a strip material configured by covering one or more belt cover cords with coating rubber, and may be configured by winding this strip material spirally multiple times in the tire circumferential direction around the outer circumferential surfaces of the cross belts 141, 142. The belt cover 143 is disposed to cover the entire area of ​​the cross belts 141, 142, and the pair of belt edge covers 144, 144 are disposed to cover the left and right edge portions of the cross belts 141, 142 from the outside in the tire radial direction.

[0018] The tread rubber 15 is disposed on the outer periphery in the tire radial direction of the carcass layer 13 and the belt layer 14 to form a tread portion of the tire 1. A pair of sidewall rubbers 16, 16 are disposed on the outer sides in the tire width direction of the carcass layer 13, respectively, to form left and right sidewall portions. A pair of rim cushion rubbers 17, 17 extend from the inner side in the tire radial direction of the left and right bead cores 11, 11 and the turned-up portions of the carcass layer 13 to the outer side in the tire width direction, to form a rim fitting surface of the bead portion.

[0019] As shown in FIG. 1, a tire 1 includes, in a ground contact region thereof, a plurality of circumferential main grooves 2 extending in the tire circumferential direction and a plurality of land portions 3 defined by the circumferential main grooves.

[0020] As shown in Fig. 1, the tire 1 has a rim protector 10. The rim protector 10 is a protrusion formed on the tire side, and is disposed in an area radially inward of the tire maximum width position A and radially outward of the rim check line R. This rim protector 10 prevents damage to the tire side caused by contact with a curb or a rim flange (not shown).

[0021] The tire side portion is defined as an annular area from the tire ground contact edge T to the rim check line R.

[0022] The tire ground contact edge T is defined as the widest position in the axial direction of the tire at the contact surface between the tire and a flat plate when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and placed perpendicular to a flat plate in a stationary state and subjected to a load corresponding to a specified load.

[0023] The specified rim refers to the "applicable rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO. The specified load refers to the "maximum load capacity" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "load capacity" specified by ETRTO. However, in JATMA, for passenger car tires, the specified internal pressure is 180 kPa, and the specified load is 88% of the maximum load capacity.

[0024] The rim check line R is a line for checking whether the tire is properly mounted on the rim, and is indicated by, for example, an annular protrusion formed on the outer surface of the bead portion.

[0025] The tire maximum width position A is defined as the maximum width position of the tire section width specified by JATMA.

[0026] The tire cross-sectional width is measured as the straight-line distance between the sidewalls, excluding any patterns or lettering on the sidewalls of the tire, when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and under no load.

[0027] As shown in FIG. 1, the tire 1 has a mold split position M in the buttress portion. The mold split position M is defined as a position corresponding to a connection portion of a split mold of a tire molding die. At this mold split position M, a rib-like protrusion extending in the tire circumferential direction is formed from residual rubber that is bitten in during tire vulcanization molding. Specifically, the split mold (not shown) is composed of a first molding die that advances and retreats in the tire radial direction to form the tread portion, and left and right second molding dies that advance and retreat in the tire axial direction to form the side portions, so that a rib-like protrusion having a width of about 2 mm to 3 mm is formed at the mold split position M.

[0028] The buttress portion is defined as a non-ground contact area formed at the connection between the profile of the tread portion and the profile of the sidewall portion, and constitutes the outer sidewall surface in the tire width direction of the shoulder land portion.

[0029] [fin] Fig. 2 is an enlarged view showing one tire side portion of the tire 1 shown in Fig. 1. Fig. 3 is an enlarged view showing the fin 9A (9B) shown in Fig. 2. Figs. 4 to 6 are a plan view (Fig. 4), a side view (Fig. 5), and a cross-sectional view (Fig. 6) showing the fin 9A (9B) shown in Fig. 2. Figs. 4 to 5 show a single fin 9A (9B) extracted from the outside.

[0030] As shown in Fig. 1, the tire 1 includes fins 9A (9B). The fins 9A (9B) are convex parts formed on the tire side parts and have the effect of generating turbulence when the tire rolls. This reduces the air resistance of the tire, improving the fuel efficiency of the tire, and also reduces pressure fluctuations around the tire, improving the noise performance of the tire (particularly the external noise performance). Furthermore, a plurality of fins 9A, 9B are arranged at predetermined intervals in the tire circumferential direction (see Fig. 7 described later).

[0031] 2, a region is defined as being 20% ​​of the tire cross-sectional height SH (see FIG. 1) on the inner and outer sides in the tire radial direction from the tire maximum width position A. At this time, a maximum position 91 of a protruding height Hf (see FIG. 5) of a fin 9A (9B) described later is within the above-mentioned 20% region. In other words, the radial distance (dimension symbols omitted in the figure) from the tire maximum width position A to the maximum position 91 of the protruding height Hf of the fin 9A (9B) is within a range of 20% or less of the tire cross-sectional height SH.

[0032] The tire section height SH is half the distance between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, with a specified internal pressure applied, and in an unloaded state.

[0033] 2, for example, a maximum position 91 of the protruding height Hf of the fin 9A (9B) is disposed radially outward of the tire maximum width position A. However, this is not limiting, and the maximum position 91 of the protruding height Hf of the fin 9A (9B) may be disposed radially inward of the tire maximum width position A (not shown).

[0034] In FIG. 3, the extension length Df of the fin 9A (9B) in the tire radial direction is in the range of 0.10≦Df / SH≦0.60 relative to the tire cross-sectional height SH (see FIG. 1), and preferably in the range of 0.20≦Df / SH≦0.30.

[0035] The radial extension length Df of the fins 9A, 9B is the radial distance of the tire between both ends 92, 92 (see Figure 3) of the fins 9A, 9B, and is measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.

[0036] For example, in the configuration of Fig. 3, a radially outer end 92 of the fin 9A (9B) is located radially inward of a tread end (reference numerals omitted in the figure) and radially inward of a mold split position M. The radially inner end 92 of the fin 9A (9B) is located radially outward of a tire maximum width position A. The entire intermediate portion 93 (see Fig. 4) of the fin 9A (9B) described later is located radially outward of the tire maximum width position A. However, this is not limited to the above, and a portion other than the intermediate portion 93, for example, a tip portion 94 of the fin 9A (9B) described later, may intersect with the tire maximum width position A (not shown).

[0037] The tread edge is defined as both ends of the tread pattern of the tire, and is the measurement point of the tread width. In the configurations of Figures 2 and 3, the end of the lug groove 31 of the shoulder land portion 3 coincides with the tread edge.

[0038] 4, the length Lf of the fin 9A (9B) in the extension direction is defined as the distance between both ends 92, 92 of the fin 9A (9B) in the longitudinal direction. An intermediate portion 93 of the fin 9A (9B) is defined as a portion ranging from the center of the length Lf of the fin 9A (9B) in the extension direction to both sides in the extension direction, the portion being in a range of 25% of the length Lf. Each of the tip portions 94, 94 of the fin 9A (9B) is defined as a portion ranging from each end 92, 92 of the fin 9A (9B) in the extension direction excluding 5% of the length Lf of the fin 9A (9B).

[0039] In this case, it is preferable that the fin 9A (9B) has an edge portion of a circular arc shape that is convex toward the tire radial outside in a plan view of the tire side portion. This improves the turbulent flow generation effect of the fin 9A (9B). For example, in the configuration of FIG. 4, the fin 9A (9B) has a semicircular or leaf-shaped planar shape, so that the edge portion of the fin 9A (9B) on the tire radial outside has an arc shape that is convex toward the tire radial outside. In addition, the maximum position (reference numerals omitted in the figure) of the width Wf of the fin 9A (9B) is in the middle part 93 of the fin 9A (9B). In addition, the minimum positions (reference numerals omitted in the figure) of the width Wf in the middle part 93 and each tip part 94, 94 are located at positions 5% of the length Lf of the fin 9A (9B) from each of the ends 92, 92 of the fin 9A (9B). In addition, the width Wf of the fin 9A (9B) gradually decreases from the maximum position of the middle part 93 to the minimum position of each tip part 94, 94. This enhances the turbulent flow generating effect of the fin 9A (9B). However, the fin 9A (9B) may have any shape, such as a rectangular shape, a trapezoidal shape, a triangular shape, an S-shape, a zigzag shape, etc., in a plan view of the tire side portion (not shown). In addition, the width Wf of the fin 9A (9B) at the middle portion 93 and each tip end 94, 94 is in the range of 0.5 mm≦Wf≦10 mm.

[0040] 4, the inclination angle θf of the fin 9A (9B) with respect to the tire circumferential direction is in the range of 10[deg]≦θf≦85[deg], and preferably in the range of 15[deg]≦θf≦40[deg]. This ensures the turbulent flow generation effect of the fin 9A (9B).

[0041] 5, the middle portion 93 of the fin 9A (9B) has a maximum position 91 of the protruding height Hf of the fin 9A (9B) from the tire side portion, i.e., a position where the protruding height Hf is a maximum value Hf_max. Each of the tip portions 94, 94 of the fin 9A (9B) includes a minimum position 95 of the protruding height Hf of the fin 9A (9B) at the middle portion 93 and each tip portion 94, 94, i.e., a position where the protruding height Hf is a minimum value Hf_min. The protruding height Hf of the middle portion 93 is in the range of 2.0 mm≦Hf≦10 mm.

[0042] The protruding height Hf of the fin 9A (9B) is measured as the distance from the side profile Prf of the tire 1 to the top of the fin 9A (9B).

[0043] The side profile Prf is the contour line that approximates the outer surface of the sidewall from the bead portion to the buttress portion as a smooth arc when viewed in a cross-section in the tire meridian direction, and is measured excluding any partial unevenness formed on the side of the tire (for example, surface finishes such as patterns, stampings such as lettering, side blocks, rim protectors, mold split marks, etc.).

[0044] The tire profile is the outline of the tire in a cross-sectional view taken along the tire meridian direction, and is measured using a laser profiler, such as a tire profile measuring device (manufactured by Matsuo Corporation).

[0045] For example, in the configuration of FIG. 5, in a side view of the fin 9A (9B), the top of the fin 9A (9B) has an arc shape, so that the maximum position 91 of the protruding height Hf is at the middle part 93 of the fin 9A (9B). Also, the minimum positions 95 of the protruding height Hf at the middle part 93 and each tip part 94, 94 are at positions 5% of the length Lf of the fin 9A (9B) from each of the ends 92, 92 of the fin 9A (9B). Also, the protruding height Hf of the fin 9A (9B) at the minimum position 95 is smaller than the protruding height Hf of the fin 9A (9B) at the maximum position 91. Also, the protruding height Hf of the fin 9A (9B) gradually decreases from the maximum position 91 of the middle part 93 to the minimum positions 95, 95 of each tip part 94, 94. This reduces the amount of change in rubber volume at the tip parts 94, 94 of the fin 9A (9B), ensuring the durability of the fin. However, the present invention is not limited to this, and the top of the fin 9A (9B) may have any shape, such as a rectangular shape, a trapezoidal shape, or a triangular shape, in a side view of the fin 9A (9B) (not shown).

[0046] 6, the fin 9A (9B) has a triangular shape in a cross section in the short direction of the fin 9A (9B). This makes it possible to reduce the rubber volume of the fin 9A (9B) while adequately ensuring the turbulent flow generation effect of the fin 9A (9B). However, this is not limited thereto, and the fin 9A (9B) may have any cross-sectional shape such as a trapezoid or semicircular shape (not shown).

[0047] In the configurations of Figs. 4 to 6, the maximum position (reference numerals omitted in the drawings) of the cross-sectional area of ​​the fin 9A (9B) in the cross section in the short direction of the fin 9A (9B) is at the middle part 93 of the fin 9A (9B). The minimum positions (reference numerals omitted in the drawings) of the cross-sectional area of ​​the middle part 93 and each tip part 94, 94 are at positions 5% of the length Lf of the fin 9A (9B) from each of the ends 92, 92 of the fin 9A (9B). The cross-sectional area of ​​the fin 9A (9B) gradually decreases from the maximum position of the middle part 93 to the minimum position of each tip part 94, 94. This increases the durability of the fin 9A (9B). However, this is not limited to the above, and the cross-sectional area of ​​the fin 9A (9B) may be constant in the longitudinal direction of the fin 9A (9B), for example, or may have a minimum value at the middle part 93 (not shown).

[0048] Fig. 7 is a side view showing the tire 1 depicted in Fig. 1. The figure shows the tire side surface on the outer side of the tire 1 in the vehicle width direction.

[0049] As shown in Fig. 7, the tire 1 has a plurality of fins 9A, 9B on the tire side. The fins 9A, 9B are arranged at a predetermined interval in the tire circumferential direction and are distributed around the tire. The interval φf [deg] between adjacent fins 9A, 9B is in the range of 10 ≦ φf ≦ 50, and preferably in the range of 20 ≦ φf ≦ 35.

[0050] For example, in the configuration of Fig. 7, twelve fins 9A, 9B are arranged at intervals φf of about 30 degrees in the tire circumferential direction. In addition, adjacent fins 9A, 9B in the tire circumferential direction are inclined in opposite directions relative to the tire circumferential direction. This enhances the turbulent flow generation effect of the fins 9A, 9B. However, this is not limited, and all fins 9A, 9B may be inclined in the same direction relative to the tire circumferential direction (not shown).

[0051] [Serrated and smooth areas] 8 and 9 are enlarged views showing a first main part of the tire 1 shown in FIG. 7. Specifically, FIG. 8 shows a unit consisting of a pair of fins 9A, 9B, a serration region 5, and a smooth region 6A, and FIG. 9 shows an enlarged view of one fin 9A (9B). FIG. 10 is a cross-sectional view taken from A showing the serration region 5 shown in FIG. 9. FIG. 11 is a cross-sectional view taken from B showing the connection portion of the serration region 5 and the smooth region 6A shown in FIG. 9. FIG. 12 is a cross-sectional view taken from C showing the connection portion of the fin 9A (9B), the serration region 5, and the smooth region 6A shown in FIG. 9.

[0052] Here, since the pair of fins 9A, 9B shown in FIG. 8 have a symmetrical structure, as shown in FIG. 9, the pair of fins 9A, 9B will be described together, with the fins 9A, 9B being referred to as fin 9A (9B).

[0053] As shown in FIGS. 7 to 9, the tire 1 includes a plurality of fins 9A, 9B as well as a serration region 5 and smooth regions 6A, 6B on the surface of the tire side portion.

[0054] As shown in Fig. 9 and Fig. 10, the serration region 5 is composed of a plurality of thin grooves 51 arranged in parallel. Also, as shown in Fig. 9, the serration region 5 is defined as a region surrounded by imaginary lines (reference numbers omitted in the figures) connecting the ends of the plurality of adjacent thin grooves 51. For example, in the configuration of Fig. 9, the ends of the plurality of thin grooves 51 on the outer side in the tire radial direction are arranged in an arc shape to form the radially outer boundary of the serration region 5, and the plurality of thin grooves 51 are connected to and terminated by the fins 9A (9B), the smooth region 6A, and the thin ribs N, forming the radially inner boundary of the serration region 5 along these. This serration region 5 improves the design of the tire side portion.

[0055] 2 and 7, the serration region 5 is disposed at the same position in the tire radial direction as the fin 9A (9B), and therefore overlaps with the fin 9A (9B) when projected in the tire circumferential direction. For example, in the configuration of FIG. 2, as shown in FIG. 3, the tire 1 includes a thin rib N formed in the tire side portion near the tire maximum width position A and extending in the tire circumferential direction, and the serration region 5 is formed in a region between the thin rib N and a mold dividing position M. Also, the radially inner end of the serration region 5 is connected to the thin rib N, and the radially outer end is separated from the mold dividing position M. However, the present invention is not limited to this, and the serration region 5 may be formed at any tire radial position (not shown) as long as it satisfies the requirements described below.

[0056] 7, the serration region 5 has an annular structure extending around the entire circumference of the tire, and the radially outer boundary of the serration region 5 has a circular shape that is continuous in the tire circumferential direction. A single serration region 5 is disposed surrounding all of the fins 9A (9B). However, this is not limiting, and the serration region 5 may be divided so as to be discontinuous in the tire circumferential direction, or may be disposed in a partial region in the tire circumferential direction (not shown).

[0057] 8 and 9, the serration region 5 connects to the side surface (reference numerals omitted in the figures) of the fin 9A (9B). Specifically, as shown in Fig. 12, the narrow grooves 51 of the serration region 5 connect to the side surface of the fin 9A (9B). This promotes the flow of residual air from the fin 9A (9B) to the serration region 5 during vulcanization molding of the tire, as described later.

[0058] Moreover, the connection length Lc1 of the serration region 5 to one side of the fin 9A (9B) is in the range of 0.60≦Lc1 / Lf≦1.00, and preferably in the range of 0.70≦Lc1 / Lf≦1.00, relative to the length Lf of the fin 9A (9B) in the extending direction. Moreover, the connection length Lc1 of the serration region 5 preferably includes the entire area of ​​the middle portion 93 (see FIG. 4) of the fin 9A (9B), and more preferably includes the entire areas of the middle portion 93 and the tip portions 94, 94 of the fin 9A (9B). This promotes the flow of residual air from the fin 9A (9B) to the serration region 5 during vulcanization molding of the tire.

[0059] The connection length Lc1 of the serration region 5 is defined as the extension length of the connection portion between the serration region 5 and the fin 9A (9B) in a direction parallel to the length Lf of the fin 9A (9B) in the extension direction.

[0060] Also, the serration region 5 is connected to the side of the fin 9A (9B) so as to surround the radially outer end 92 of the fin 9A (9B). Furthermore, it is preferable that the serration region 5 is connected to the side so as to surround a range of 5% of the length Lf of the fin 9A (9B) from the radially outer end 92 of the fin 9A (9B) (see FIG. 4), in other words, it is connected to each of the left and right side of the fin 9A (9B) in the above range. This promotes the flow of residual air from the fin 9A (9B) to the serration region 5 during vulcanization molding of the tire.

[0061] For example, in the configuration of FIG. 8, as shown in FIG. 9, the serration region 5 is connected to one side surface of the fin 9A (9B), here the entire outer side surface in the tire radial direction (Lc1 / Lf = 1.00). Also, the serration region 5 is connected to the other side surface of the fin 9A (9B), here a part of the inner side surface in the tire radial direction. Further, the serration region 5 is connected to the fin 9A (9B) so as to surround the radially outer end 92 of the fin 9A (9B).

[0062] Also, in FIGS. 3 and 9, the extension length Df of the fin 9A (9B) in the tire radial direction is in the range of 0.50 ≦ Df / Ds < 1.00 with respect to the radial width Ds of the serration region 5, preferably in the range of 0.60 ≦ Df / Ds ≦ 0.90. With the above lower limit, the visual recognizability of the fin 9A (9B) is ensured, and with the above upper limit, the flow of residual air from the fin 9A (9B) to the serration region 5 is ensured.

[0063] Also, as shown in FIGS. 8 and 9, it is preferable that the serration region 5 extends radially outward of the tire more than the end 92 of the fin 9A (9B) on the radially outer side of the tire. Thereby, the exhaust performance at the end 92 of the fin 9A (9B) is improved, and the flow of residual air from the fin 9A (9B) to the serration region 5 is promoted. Also, the distance D1 from the end 92 of the fin 9A (9B) on the radially outer side of the tire to the radially outer boundary line of the serration region 5 is in the range of 0 [mm] < D1, preferably in the range of 1.5 [mm] ≦ D1. The upper limit of the distance D1 is not particularly limited, but is restricted by the above ratio Df / Ds.

[0064] Also, as shown in FIGS. 8 and 9, it is preferable that the serration region 5 extends radially inward of the tire more than the end 92 of the fin 9A (9B) on the radially inner side of the tire. Thereby, the exhaust performance at the end 92 of the fin 9A (9B) is improved, and the flow of the residual air from the fin 9A (9B) to the serration region 5 is promoted. Further, the distance D2 from the end 92 of the fin 9A (9B) on the radially inner side of the tire to the radially inner boundary line of the serration region 5 is in the range of 0 [mm] < D2, preferably in the range of 1.0 [mm] ≦ D2. The upper limit of the distance D2 is not particularly limited, but is restricted by the above-described ratio Df / Ds.

[0065] Also, in FIG. 9, the inclination angle θs of the plurality of fine grooves 51 with respect to the tire radial direction is in the range of -10 [deg] ≦ θs ≦ 10 [deg], preferably in the range of -1 [deg] ≦ θs ≦ 1 [deg]. Thereby, the flow of the residual air from the fin 9A (9B) to the serration region 5 is promoted. Further, in FIG. 10, the groove width Wg of the fine groove 51 is in the range of 0.60 [mm] ≦ Wg ≦ 0.70 [mm], and the groove depth Hg is in the range of 0.30 [mm] ≦ Hg ≦ 0.35 [mm]. Also, the groove width Wg of the fine groove 51 is in the range of 0.40 ≦ Wg / Pg ≦ 0.80 with respect to the pitch length Pg of the fine groove 51, preferably in the range of 0.50 ≦ Wg / Pg ≦ 0.65.

[0066] The inclination angle θs of the fine groove 51 is measured as the angle formed by the virtual straight line passing through both ends of the fine groove 51 and the tire radial direction, and is defined with one direction in the tire circumferential direction as positive.

[0067] The groove width Wg of the fine groove 51 is measured as the maximum value of the distance between the opposing groove walls at the groove opening on the tire side surface in the unloaded state where the tire is mounted on the specified rim and filled with the specified internal pressure.

[0068] The groove depth Hg of the fine groove 51 is measured as the maximum value of the distance from the tire side surface to the groove bottom in the unloaded state where the tire is mounted on the specified rim and filled with the specified internal pressure.

[0069] As shown in Figs. 9 and 11, the smooth regions 6A and 6B have a smooth surface. Specifically, the smooth regions 6A and 6B are defined as regions having a continuous surface without grooves or uneven portions. For example, in the configurations of Figs. 8 and 9, the smooth region 6A is formed as a continuous region surrounding the entire inscription of the side brand "YOKOHAMA". Therefore, the side brand itself does not constitute the smooth regions 6A and 6B. By arranging the smooth regions 6A and 6B to surround the side brand, the visibility of the side brand is improved compared to a configuration (not shown) in which the side brand is arranged in the serration region 5.

[0070] As shown in Fig. 7, the smooth regions 6A and 6B are disposed at the same position in the tire radial direction relative to the fin 9A (9B), and therefore overlap the fin 9A (9B) when projected in the tire circumferential direction. For example, in the configuration of Fig. 7, the smooth regions 6A and 6B are disposed in an area (reference numerals omitted in the figure) surrounded by the serration region 5, the narrow rib N formed near the tire maximum width position A, and the pair of 9A and 9B, as shown in Fig. 8. Also, the side brands "YOKOHAMA" and "ADVAN" are marked in the center of the smooth regions 6A and 6B.

[0071] In this embodiment, a plurality of smooth regions 6A, 6B are arranged at predetermined positions in the tire circumferential direction as shown in Fig. 7. However, this is not limiting, and a single serration region 5 may be arranged at any position in the tire circumferential direction (not shown).

[0072] 7, one smooth region 6A; 6B is disposed across a pair of adjacent fins 9A, 9B and is connected to each of the pair of adjacent fins 9A, 9B. The smooth regions 6A, 6B are connected to the radially inner boundary of the serration region 5.

[0073] 8 and 9, the smooth region 6A is connected to the side surface (reference numerals omitted in the figures) of the fin 9A (9B). Specifically, as shown in Fig. 12, the smooth region 6A is connected to the base of the side surface of the fin 9A (9B). This promotes the flow of residual air from the smooth region 6A to the fin 9A (9B) during vulcanization molding of the tire, as described later.

[0074] 7, a plurality of elongated smooth surfaces (reference numbers omitted in the drawing) are disposed between adjacent smooth regions 6A and 6B in the tire circumferential direction. However, these smooth surfaces are not connected to any of the fins 9A and 9B, and therefore do not correspond to the above-described smooth regions 6A and 6B.

[0075] 9, the connection length Lc2 of the smooth regions 6A, 6B to the other side of the fin 9A (9B) is in the range of 0.60≦Lc2 / Lf≦0.95, and preferably in the range of 0.70≦Lc2 / Lf≦0.90, relative to the length Lf of the fin 9A (9B) in the extending direction. The connection length Lc2 of the smooth regions 6A, 6B preferably includes the entire intermediate portion 93 (see FIG. 4) of the fin 9A (9B), and more preferably includes the entire intermediate portion 93 and tip portions 94, 94 of the fin 9A (9B). This improves the external visibility of the finished tire.

[0076] The connection length Lc2 of the smooth regions 6A, 6B is defined as the extension length of the connection between the smooth regions 6A, 6B and the fin 9A (9B) in a direction parallel to the extension direction length Lf of the fin 9A (9B).

[0077] Also, in FIG. 9, the connection length Lc2 of the smooth regions 6A and 6B to the other side surface of the fin 9A (9B) is in the range of 0.60 ≦ Lc2 / Lc1 ≦ 0.95 with respect to the connection length Lc1 of the serration region 5 to one side surface of the fin 9A (9B), and preferably in the range of 0.70 ≦ Lc2 / Lc1 ≦ 0.90. In such a configuration, since the connection length Lc1 of the serration region 5 is longer than the connection length Lc2 of the smooth region 6A, the residual air flow from the smooth region 6A through the fin 9A (9B) to the serration region 5 is promoted.

[0078] For example, in the configuration of FIG. 8, as shown in FIG. 9, each of the serration region 5 and the smooth region 6A is connected to one side surface of the fin 9A (9B), here the inner side surface in the tire diameter direction. Further, the serration region 5 is connected to the side surface of the fin 9A (9B) so as to include a range of 5% of the length Lf of the fin 9A (9B) from the radially outer end 92 of the fin 9A (9B) (see FIG. 4), and the smooth region 6A is connected to the side surface of the fin 9A (9B) so as to include a range of 5% of the length Lf of the fin 9A (9B) from the radially inner end 92 of the fin 9A (9B).

[0079] Also, as shown in FIGS. 8 and 9, it is preferable that the smooth region 6A extends radially inward of the tire more than the end 92 of the fin 9A (9B) on the radially inner side of the tire. Further, the distance D2' (equal to the distance D2 in FIG. 9. Dimension symbols in the figure are omitted) from the end 92 of the fin 9A (9B) on the radially inner side of the tire to the radially inner boundary line of the smooth region 6A is in the range of 0 [mm] < D2', and preferably in the range of 1.0 [mm] ≦ D2'. The upper limit of the distance D2' is not particularly limited, but is restricted by the above-described ratio Lc2 / Lf.

[0080] [Modification Example] Figures 13 and 14 are enlarged views showing a second main part of the tire 1 shown in Figure 7. Specifically, Figure 13 shows a unit consisting of a pair of fins 9A, 9B, the serration region 5 and the second smooth region 6B, and Figure 14 shows an enlarged view of one fin 9A (9B). In these figures, the same components as those in the first main part shown in Figure 7 are denoted by the same reference numerals, and their description will be omitted.

[0081] In the configurations of Figs. 8 and 9, as described above, the first smooth region 6A is disposed across a pair of fins 9A, 9B adjacent in the tire circumferential direction. At this time, the pair of fins 9A, 9B are inclined in a direction approaching each other toward the tire radially outward. Therefore, the serration region 5 is connected to the entire area of ​​each of the pair of fins 9A, 9B on the tire radially outer side, and the first smooth region 6A is connected to each of the pair of fins 9A, 9B on the tire radially inner side. In addition, the first smooth region 6A has a trapezoidal shape in which the tire circumferential width is narrowed toward the tire radially outward.

[0082] In contrast, in the configurations of Fig. 13 and Fig. 14, the second smooth region 6B is disposed across a pair of fins 9A, 9B adjacent in the tire circumferential direction, similar to the configuration of Fig. 8. At this time, the pair of fins 9A, 9B are inclined in a direction away from each other toward the tire radially outward. Therefore, the serration region 5 is connected to the entire area of ​​the side surfaces of the pair of fins 9A, 9B on the inner side in the tire radial direction, and the second smooth region 6B is connected to the side surfaces of the pair of fins 9A, 9B on the outer side in the tire radial direction. In addition, the second smooth region 6B has a trapezoidal shape whose width in the tire circumferential direction increases toward the tire radially outward.

[0083] [effect] As described above, [1] the tire 1 includes, in the tire side portion, the fin 9A (9B) that extends while inclining with respect to the tire circumferential direction and the tire radial direction, the serration region 5 consisting of a plurality of narrow grooves 51 arranged in parallel, and the smooth region 6A having a smooth surface (see FIG. 9). The serration region 5 is connected to one side surface of the fin 9A (9B). The smooth region 6A is connected to the other side surface of the fin 9A (9B).

[0084] In this configuration, (1) the fins 9A (9B) generate turbulence during tire rolling, thereby reducing the air resistance of the tire and improving the fuel efficiency of the tire. Also, (2) the fins 9A (9B) are interposed between the serration region 5 and the smooth region 6A, so that the residual air in the smooth region 6A efficiently flows into the serration region 5 through the fins 9A (9B) during vulcanization of the tire. This promotes the flow of the residual air from the smooth region 6A to the serration region 5. This has the advantage of suppressing vulcanization failure in the smooth region 6A, particularly the occurrence of poor tire appearance due to residual air. In particular, in the long smooth region 6A as shown in FIG. 8, there is a problem that poor appearance due to residual air is likely to occur in the central region in the tire circumferential direction (more specifically, the region between the side land and the serration region 5 in FIG. 8). In this tire 1, the above problem can be effectively solved.

[0085] [2] In the tire 1 described in [1] above, the inclination angle θs (see FIG. 9) of the narrow grooves 51 with respect to the tire radial direction is in the range of −10 degrees≦θs≦10 degrees. This has the advantage of promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0086] [3] In the tire 1 described in [1] or [2] above, the intermediate portion 93 of the fin 9A (9B) is defined as a portion in a range of 25% of the length Lf on both sides of the center of the length Lf of the fin 9A (9B) in the extension direction (see FIG. 5). The intermediate portion 93 of the fin 9A (9B) has a maximum position 91 of the protruding height Hf of the fin 9A (9B) from the tire side portion. This has the advantage of promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0087] [4] In the tire 1 according to any one of [1] to [3] above, the intermediate portion 93 of the fin 9A (9B) is defined as a portion ranging from the center of the length Lf of the fin 9A (9B) in the extension direction to both sides of the length Lf (see FIG. 5). Each tip portion 94, 94 of the fin 9A (9B) is defined as a portion ranging from each end 92, 92 in the extension direction of the fin 9A (9B) excluding 5% of the length Lf of the fin 9A (9B). At least one of the tip portions 94, 94 includes the intermediate portion 93 and a minimum position 95 of the protruding height Hf of the fin 9A (9B) at each tip portion 94, 94. This has the advantage of promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0088] [5] In the tire 1 according to any one of the above items [1] to [4], the connection length Lc1 of the serration region 5 to one side of the fin 9A (9B) is in the range of 0.60≦Lc1 / Lf≦1.00 with respect to the length Lf of the fin 9A (9B) in the extending direction (see FIG. 9). This has the advantage of promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0089] [6] In the tire 1 according to any one of the above items [1] to [5], the serration region 5 extends radially outward in the tire direction beyond an end 92 of the fin 9A (9B) at the outer side in the tire radial direction (see FIG. 9). This has the advantage of improving the exhaust performance at the end 92 of the fin 9A (9B), and promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0090] [7] In the tire 1 according to any one of the above items [1] to [6], the serration region 5 extends radially inward in the tire direction further than an end 92 of the fin 9A (9B) on the inner side in the tire radial direction (see FIG. 9). This has the advantage of improving the exhaust performance at the end 92 of the fin 9A (9B), and promoting the flow of residual air from the fin 9A (9B) to the serration region 5.

[0091] [8] In the tire 1 according to any one of the above items [1] to [7], the extension length Df of the fin 9A (9B) in the tire radial direction is in the range of 0.50≦Df / Ds<1.00 with respect to the radial width Ds of the serration region 5. The lower limit ensures the external visibility of the fin 9A (9B), and the upper limit has the advantage of ensuring the flow of residual air from the fin 9A (9B) to the serration region 5.

[0092] [9] In the tire 1 according to any one of the above items [1] to [8], the inclination angle θf (see FIG. 4) of the fin 9A (9B) with respect to the tire circumferential direction is in the range of 10[deg]≦θf≦85[deg]. This has the advantage of ensuring the turbulent flow generation effect of the fin 9A (9B).

[0093]

[10] The tire 1 is the tire 1 according to any one of the above [1] to [9], and further includes a plurality of fins 9A, 9B on the tire side portion (see FIG. 7). The fins 9A, 9B adjacent to each other in the tire circumferential direction are inclined in opposite directions relative to the tire circumferential direction. This has the advantage of enhancing the turbulence generation effect of the fins 9A, 9B compared to a configuration (not shown) in which the plurality of fins are inclined in the same direction relative to the tire circumferential direction.

[0094]

[11] The tire 1 is the tire 1 according to any one of the above [1] to

[10] , further comprising a plurality of fins 9A, 9B on the tire side portion (see FIG. 7). The smooth regions 6A, 6B are connected to the other side surfaces of the fins 9A, 9B adjacent to each other in the tire circumferential direction (see FIG. 8 and FIG. 13). This has the advantage of promoting the flow of residual air from the fins 9A (9B) to the serration region 5.

[0095]

[12] In the tire 1 according to any one of the above items [1] to

[10] , the connection length Lc2 of the smooth regions 6A, 6B to the other side surface of the fin 9A (9B) is in the range of 0.60≦Lc2 / Lc1≦0.95 with respect to the connection length Lc1 of the serration region 5 to one side surface of the fin 9A (9B) (see FIG. 9). With this configuration, the connection length Lc1 of the serration region 5 is longer than the connection length Lc2 of the smooth region 6A, which has the advantage of promoting the flow of residual air from the smooth region 6A toward the serration region 5 via the fin 9A (9B).

[0096] Applies to In this embodiment, as described above, a pneumatic tire has been described as an example of a tire. However, the present invention is not limited to this, and the configuration described in this embodiment can be arbitrarily applied to other tires within the scope of what is obvious to a person skilled in the art. Examples of other tires include airless tires and solid tires. EXAMPLES

[0097] FIG. 15 is a table showing the results of performance tests of the tire according to the embodiment of the present invention.

[0098] In this performance test, several types of test tires were evaluated for (1) appearance defects and (2) air resistance. In addition, test tires with a tire size of 165 / 50R16 75V were mounted on JATMA-specified rims, and the test tires were subjected to JATMA-specified internal pressure and load.

[0099] (1) In the evaluation of appearance defects, an inspector produces 100 test tires and visually inspects the occurrence of appearance defects in the tire side caused by residual air during tire vulcanization. Based on the results of this inspection, an index evaluation is made with the comparative example set as the standard (100). The higher the value, the better.

[0100] (2) In the evaluation of air resistance, a wind tunnel test is conducted on a vehicle model in which a tire model is attached to a body model of a motor-assisted passenger car, and the vehicle is run at a speed equivalent to 80 km / h. The aerodynamic characteristics Ga are calculated based on the aerodynamic resistance coefficient using fluid analysis software based on the lattice Boltzmann method. Then, based on the calculation results, an index evaluation is performed with the comparative example set as the standard (100). The higher the value, the better the evaluation.

[0101] The test tire of the embodiment has the configuration of Fig. 1, and includes a total of 12 fins 9A, 9B, a serration region 5, smooth regions 6A, 6B, and a side brand (reference numbers omitted in the figure) on the tire side as shown in Fig. 7. The tire cross-sectional height SH is 82.7 [mm], the length Lf of the fin 9A (9B) in the extension direction is 57.1 [mm], and the radial width Ds of the serration region 5 is 25.9 [mm]. The test tire of the comparative example is the test tire of the embodiment 1, except that the serration region is omitted, and the test tire includes only a total of 12 fins 9A, 9B, smooth regions 6A, 6B, and a side brand on the tire side.

[0102] As the test results show, in the test tires of the examples, the appearance defects of the tires are reduced, and the air resistance of the tires is also reduced. [Explanation of symbols]

[0103] 1 tire; 2 circumferential main groove; 3 land portion; 31 lug groove; 5 serration area; 51 fine groove; 6A, 6B smooth area; 9A, 9B fin; 91 maximum position; 92 end; 93 middle portion; 94 tip portion; 95 minimum position; 10 rim protector; 11 bead core; 12 bead filler; 13 carcass layer; 14 belt layer; 141, 142 cross belt; 143 belt cover; 144 belt edge cover; 15 tread rubber; 16 sidewall rubber; 17 rim cushion rubber

Claims

1. A tire including, in a tire side portion, fins extending at an angle with respect to the tire circumferential direction and the tire radial direction, a serration region consisting of a plurality of narrow grooves arranged in parallel, and a smooth region having a smooth surface, the serration region connects to one side of the fin; and The tire is characterized in that the smooth region connects to the other side of the fin.

2. 2. The tire according to claim 1, wherein an inclination angle θs of the plurality of narrow grooves with respect to the tire radial direction is in a range of −10 degrees≦θs≦10 degrees.

3. The intermediate portion of the fin is defined as a portion ranging from the center of the length Lf of the fin in the extension direction to 25% of the length Lf on both sides in the extension direction, and The tire of claim 1 , wherein the intermediate portion of the fin defines a maximum protruding height of the fin from the tire side portion.

4. The intermediate portion of the fin is defined as a portion ranging from the center of the length Lf in the extension direction of the fin to 25% of the length Lf on both sides in the extension direction, Each tip of the fin is defined as a portion of the fin excluding 5% of the length Lf from each end of the fin in the extension direction, and The tire of claim 1 , wherein at least one of said tip portions includes a minimum point of projection height of said fin at said intermediate portion and at each tip portion.

5. The tire according to claim 1 , wherein a connection length Lc1 of the serration region to the one side surface of the fin, relative to a length Lf of the fin in the extending direction, is in a range of 0.60≦Lc1 / Lf≦1.

00.

6. The tire according to claim 1 , wherein the serration region extends radially outwardly of the tire beyond the radially outward end of the fin.

7. The tire according to claim 1 , wherein the serration region extends radially inward of the tire radially inner end of the fin.

8. The tire according to claim 1 , wherein an extension length Df of the fin in the tire radial direction is in a range of 0.50≦Df / Ds<1.00 relative to a radial width Ds of the serration region.

9. The tire according to claim 1, wherein an inclination angle θf of the fin with respect to the tire circumferential direction is in a range of 10 degrees≦θf≦85 degrees.

10. The tire according to claim 1 , wherein a plurality of the fins are provided on a tire side portion, and the fins adjacent to each other in the tire circumferential direction are inclined in opposite directions to each other with respect to the tire circumferential direction.

11. The tire according to claim 1 , comprising a plurality of the fins on a tire side portion, and the smooth region is connected to each of the other side surfaces of the fins adjacent to each other in the tire circumferential direction.

12. 2. The tire according to claim 1, wherein a connection length Lc2 of the smooth region to the other side surface of the fin and a connection length Lc1 of the serration region 5 to the one side surface of the fin are in a range of 0.60≦Lc2 / Lc1≦0.95.

Images