Tire

Abstract

To provide a tire improving durability performance during high speed travelling.SOLUTION: A tire 1 is such one the installation orientation of which to a vehicle is designated, and includes: a tread part 2 having a ground plane 2s; an inner side part 3i extending from the vehicle inside of the tread part 2 to the inside in a tire radial direction when mounted on the vehicle, and an outer side part 3o extending from the vehicle outside of the tread part 2 to the inside in the tire radial direction when mounted on the vehicle. At least one part of the inner side part 3i has a serration area 6 in which a plurality of ridges 5 are arrayed in parallel. Each of the plurality of ridges 5 extends to a tire circumferential direction at an angle of 45-90°. The outer side part 3o does not have the serration area 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire having a specified orientation for mounting on a vehicle. [Background technology]

[0002] Various tires suitable for high-speed driving, which have a specified mounting direction on a vehicle, have been proposed. For example, Patent Document 1 below proposes a pneumatic tire with improved durability by specifying the inclination direction of the rubber strips that make up the tread rubber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-093877 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the inner side portion, which is located on the inside of the vehicle when mounted on the vehicle, tends to become hot when the vehicle is traveling at high speeds, and further improvement has been desired even in the pneumatic tire of Patent Document 1.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire that can improve durability during high-speed running. [Means for solving the problem]

[0006] The present invention is a tire whose mounting orientation on a vehicle is specified, and includes a tread portion having a contact surface, an inner side portion that extends radially inward from the vehicle-inside side of the tread portion when mounted on the vehicle, and an outer side portion that extends radially inward from the vehicle-outside side of the tread portion when mounted on the vehicle, wherein at least a portion of the inner side portion has a serration region in which a plurality of ridges are arranged in parallel, each of the plurality of ridges extending at an angle of 45 to 90 degrees relative to the tire circumferential direction, and the outer side portion does not have the serration region. [Effects of the Invention]

[0007] The tire of the present invention has the above-mentioned configuration, and thus can improve durability during high-speed running. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an embodiment of a pneumatic tire of the present invention. [Figure 2] FIG. [Figure 3] FIG. 10 is an enlarged perspective view of a ridge according to another embodiment. [Figure 4] FIG. 2 is an enlarged view of part A in FIG. [Figure 5] FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2. [Figure 6] FIG. 1 is a schematic diagram of a mold for vulcanizing and molding a tire. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a tire meridian cross-sectional view showing a tire 1 of this embodiment in a normal state. Here, when the tire 1 is a pneumatic tire, the "normal state" refers to a state in which the tire 1 is mounted on a normal rim, adjusted to a normal internal pressure, and no load is applied. Unless otherwise specified below, the dimensions of each part of the tire 1 are values ​​measured in this normal state.

[0010] If there is a standard system that includes the standard on which tire 1 is based, a "genuine rim" is a rim that is determined for each tire by that standard, for example, a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO. If there is no standard system that includes the standard on which tire 1 is based, a "genuine rim" is a rim that can be mounted on a rim and does not cause air leakage, and that has the smallest rim diameter and narrowest rim width among those rims.

[0011] "Normal internal pressure" is the air pressure set for each tire by a standard set by each standard, if there is one that includes the standard on which tire 1 is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE." If there is no standard set that includes the standard on which tire 1 is based, "normal internal pressure" is the air pressure set for each tire by the manufacturer, etc.

[0012] As shown in Fig. 1, the tire 1 of this embodiment has a specified orientation for mounting on a vehicle. A suitable example of the tire 1 is a pneumatic tire suitable for high-speed driving such as circuit driving. The tire 1 of this embodiment is a so-called slick tire, which has no grooves or the like formed on the contact surface 2s. The tire 1 is not limited to this embodiment, and can be applied to various types of tires 1, such as pneumatic tires for passenger cars, heavy-duty tires, and airless tires.

[0013] The tire 1 includes, for example, a tread portion 2, a pair of side portions 3, and a pair of bead portions 4. The tread portion 2 is a portion that constitutes a contact surface 2s. The pair of side portions 3 are portions that extend radially inward from both sides of the tread portion 2 in the tire axial direction.

[0014] The pair of side portions 3 in this embodiment include inner side portions 3i that extend radially inward from the vehicle inner side of the tread portion 2 when mounted on the vehicle, and outer side portions 3o that extend radially inward from the vehicle outer side of the tread portion 2 when mounted on the vehicle.

[0015] At least a portion of the inner side portion 3i of this embodiment has a serration region 6 in which a plurality of ridges 5 are arranged in parallel. Such a tire 1 can cool the inner side portion 3i, which tends to become hot during high-speed driving, and can improve durability during high-speed driving. Furthermore, the serration region 6 of such an inner side portion 3i can absorb heat from the engine, brakes, etc. after high-speed driving, and can prevent the tire 1 from driving in a state of reduced internal pressure due to cooling, thereby improving the long-distance driving performance of the tire 1.

[0016] On the other hand, the outer side portion 3o of this embodiment does not have a serration region 6. Such a tire 1 has excellent aerodynamic performance on the outer side of the vehicle when traveling at high speeds, and can also clearly display insignia such as marks and character strings.

[0017] Fig. 2 is a side view of the inner side portion 3i. As shown in Fig. 2, each of the multiple ridges 5 preferably extends at an angle θ of 45 to 90° with respect to the tire circumferential direction. Fig. 2 illustrates a ridge 5 extending in the tire radial direction, i.e., a ridge 5 with an angle θ of approximately 90°. Here, the angle θ of the ridge 5 is the angle θ with respect to the tire circumferential direction of a straight line connecting the start point 5a of the ridge 5 located on the outer side in the tire radial direction and the end point 5b located on the inner side in the tire radial direction.

[0018] Such ridges 5 can generate turbulence by rotation during high-speed running, and can efficiently cool the inner side portion 3i. Therefore, the tire 1 of this embodiment can suppress a temperature rise in the inner side portion 3i and improve durability during high-speed running. From this perspective, the angle θ of the ridges 5 is more preferably 70 to 90°.

[0019] As shown in Figure 1, in a more preferred embodiment, the ground contact patch 2s has an inner ground contact edge Ti and an outer ground contact edge To. The axial width between the inner ground contact edge Ti and the outer ground contact edge To is the tread width TW. The axial center position between the inner ground contact edge Ti and the outer ground contact edge To is the tire equator C.

[0020] Here, when the tire 1 is a pneumatic tire, the inner ground contact edge Ti is the ground contact position that defines the innermost side of the ground contact patch 2s when the tire 1 is mounted on a vehicle and is in contact with a flat surface at a camber angle of 0°, with a load that is 70% of the normal load of the tire 1 in its normal state. Also, when the tire 1 is a pneumatic tire, the outer ground contact edge To is the ground contact position that defines the outermost side of the ground contact patch 2s when the tire 1 is in its normal state and is in contact with a flat surface at a camber angle of 0°.

[0021] "Normal load" is the load specified for each tire by a standard system that includes the standard on which tire 1 is based, if such a system exists; for JATMA, it is "Maximum Load Capacity," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is "LOAD CAPACITY." If there is no standard system that includes the standard on which tire 1 is based, "Normal load" is the load specified for each tire by the manufacturer, etc., as the maximum load that can be applied when using tire 1.

[0022] The serration region 6 of this embodiment includes a main portion 6a extending radially inward from the inner ground contact edge Ti, and an extension portion 6b extending axially inward from the inner ground contact edge Ti on the ground contact surface 2s.

[0023] When rubber particles adhere to the contact surface 2s during circuit running, known as pickup, the serration region 6 reduces the contact area with the adhered rubber particles, making it easier to separate the adhered rubber particles. Therefore, the tire 1 of this embodiment can shorten the time during which performance deteriorates due to pickup during circuit running, and can improve long-distance running performance.

[0024] The axially inner end 6e of the extension portion 6b is preferably located within 5% of the tread width TW from the inner ground contact edge Ti. The inner end 6e of the extension portion 6b is preferably located at the axially starting point 5a of the ridge 5. Such a serration region 6 has little effect on the grip force of the ground contact patch 2s, allowing the tire 1 to maintain good steering stability.

[0025] The height H of the serration region 6 in the tire radial direction is preferably 50% or more of the cross-sectional height Sh of the tire 1. Such a serration region 6 can suppress temperature rise over the entire area of ​​the inner side portion 3i, improving the durability performance of the tire 1 during high-speed running. By suppressing temperature rise over the entire area of ​​the inner side portion 3i, such a tire 1 can suppress temperature rise in the tire cavity, improving long-distance running performance.

[0026] 2, each of the multiple ridges 5 extends linearly, for example. In this case, the angle θ of the ridge 5 is the angle θ of the line connecting the start point 5a and end point 5b of the ridge 5 with respect to the tire radial direction, and is equal to the angle θ of the longitudinal direction of the ridge 5 with respect to the tire radial direction. As will be described later, such a ridge 5 can promote the discharge of air during vulcanization molding, and is useful for suppressing poor appearance of the tire 1.

[0027] Fig. 3 is an enlarged perspective view of a ridge 5A according to another embodiment. As shown in Fig. 3, each of the ridges 5A may include, for example, a curved portion 5c. In this case, the angle θ of the ridge 5A is the angle θ of a straight line connecting the start point 5a and the end point 5b of the ridge 5 relative to the tire radial direction. Such a ridge 5A can increase the length L1 of the ridge 5A, thereby more reliably suppressing temperature increases in the inner side portion 3i during high-speed driving.

[0028] The ridge 5A may be formed entirely of curved portions 5c, or may include curved portions 5c and straight portions. The radius of curvature R1 of the curved portions 5c may be, for example, a single radius of curvature R1, or may be composed of multiple radii of curvature R1, or the radius of curvature R1 may change continuously. The number of curved portions 5c may be one or more. When there are multiple curved portions 5c, they may be curved in the same direction or in opposite directions.

[0029] The length L1 along each of the ridges 5A is preferably 200% or less of the linear distance L2 connecting the start point 5a and end point 5b of each of the ridges 5A. Such ridges 5A prevent the length L1 of the ridges 5A from becoming excessively large, and as will be described later, promote the discharge of air during vulcanization molding, thereby helping to prevent poor appearance of the tire 1.

[0030] Fig. 4 is an enlarged view of part A in Fig. 1. As shown in Fig. 4, the multiple ridges 5 of this embodiment protrude axially outward from the side reference plane 3s that defines the profile of the inner side portion 3i. Such ridges 5 can efficiently generate turbulence in the inner side portion 3i, improving the cooling effect of the inner side portion 3i during high-speed driving.

[0031] The side reference surface 3s of this embodiment is curved in the tire meridian cross section. The minimum curvature radius R2 of the side reference surface 3s is preferably 5 mm or more. Such a side reference surface 3s can suppress stress concentration and disperse strain, thereby suppressing the occurrence of damage such as cracks, even when an excessive load is applied to the tire 1.

[0032] Each of the inner side portion 3i and the outer side portion 3o (shown in FIG. 1) includes a sidewall rubber 3G. The maximum height h of each of the multiple ridges 5 from the side reference plane 3s is 70% or less of the maximum thickness t of the sidewall rubber 3G. Such ridges 5 are prevented from protruding excessively, thereby preventing molding defects during vulcanization molding.

[0033] Fig. 5 is a cross-sectional view taken along line BB in Fig. 2. As shown in Fig. 4 and Fig. 5, each of the multiple ridges 5 has, for example, a top surface 5d extending along the side reference surface 3s and a pair of slopes 5e connecting the top surface 5d and the side reference surface 3s. Such ridges 5 can increase the surface area and promote heat exchange with the outside air, thereby suppressing a temperature increase during high-speed running of the tire 1 and a temperature decrease after high-speed running.

[0034] The total surface area of ​​the multiple ridges 5 is preferably 130% or more of the reference area of ​​the serration region 6 of the side reference surface 3s. Such ridges 5 have a large surface area and can more reliably suppress temperature increases during high-speed running of the tire 1 and temperature decreases after high-speed running.

[0035] Here, the total surface area of ​​the multiple ridges 5 is the sum of the total area of ​​the top surfaces 5d and the total area of ​​the slopes 5e of all the ridges 5. The reference area is the surface area on the side reference surface 3s when the serration region 6 is projected onto the side reference surface 3s.

[0036] The total area of ​​the top surfaces 5d of the multiple ridges 5 is preferably 50% or less of the reference area. Such ridges 5 have a small contact area with adhered rubber particles when picked up during circuit driving, and can facilitate the removal of the adhered rubber particles.

[0037] 1, the tire 1 preferably includes a carcass 8 spanning between the bead cores 7 of a pair of bead portions 4, and a belt layer 9 disposed radially outward of the carcass 8 in the tread portion 2. The belt layer 9 of this tire 1 can reduce the weight of the tire while suppressing distortion of the tread portion 2 under load, thereby improving steering stability.

[0038] The carcass 8 of this embodiment has a first carcass ply 8A and a second carcass ply 8B disposed radially outward of the first carcass ply 8A in the tread portion 2. Such a carcass 8 suppresses deformation under heavy load and helps to improve the steering stability and durability of the tire 1.

[0039] The first carcass ply 8A preferably includes a main body portion 8a spanning the space between the pair of bead portions 4, and a pair of turned-up portions 8b that are continuous with the main body portion 8a and are turned up from the inside to the outside in the tire axial direction around the bead core 7. The second carcass ply 8B extends, for example, from the tread portion 2 toward the inside in the tire radial direction along the sidewall rubber 3G of the side portion 3, and terminates at the bead portions 4. Such a second carcass ply 8B can achieve both suppression of deformation under heavy load and weight reduction.

[0040] The belt layer 9 has, for example, a first belt ply 9A, a second belt ply 9B disposed radially outward of the first belt ply 9A, and a third belt ply 9C disposed radially outward of the second belt ply 9B. Such a belt layer 9 can increase the rigidity of the tread portion 2, suppress distortion under load, and improve the steering stability of the tire 1.

[0041] The belt layer 9 has, for example, a pair of outer ends 9e that are outermost in the tire axial direction. The serration region 6 of this embodiment is a region that covers the outer ends 9e of the belt layer 9 that are located on the inner side of the vehicle when mounted on the vehicle. Such serration region 6 suppresses temperature rise near the outer ends 9e of the belt layer 9, which have a large amount of distortion and are likely to become points of origin for damage, and can improve the durability performance of the tire 1 when running at high speeds.

[0042] Fig. 6 is a schematic diagram of a mold 20 for vulcanizing and molding the tire 1. As shown in Fig. 6, the tire 1 of this embodiment is vulcanized and molded using a plurality of molds 20. The plurality of molds 20 includes, for example, at least a plurality of segments 21, an inner side plate 22A, and an outer side plate 22B.

[0043] 2 and 6, the inner side portion 3i has a parting line 10 extending in the tire circumferential direction, which is formed by, for example, a plurality of molds 20 for vulcanizing and molding the tire 1. The main body portion 6a of the serration region 6 in this embodiment is provided at a position including the parting line 10.

[0044] In such a tire 1, air inside the tire 1 can be discharged from the parting line 10 via the serration region 6 when the mold 20 is clamped, and poor appearance due to residual air can be suppressed.

[0045] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified and practiced in various ways.

[0046] [Note] The present invention is as follows.

[0047] [Invention 1] A tire that is specified for installation on a vehicle, a tread portion having a ground contact surface; an inner side portion extending radially inward from an inner side of the tread portion when the tire is mounted on a vehicle; an outer side portion extending radially inward from the vehicle-outer side of the tread portion when the tire is mounted on a vehicle, At least a portion of the inner side portion has a serration region in which a plurality of ridges are arranged in parallel, Each of the plurality of ridges extends at an angle of 45 to 90 degrees with respect to the tire circumferential direction, The outer side portion does not have the serration region. tire.

[0048] [Invention 2] the ground contact surface has an inner ground contact end that defines the innermost side of the vehicle when mounted on the vehicle, A tire according to Invention 1, wherein the serration region includes a main body portion extending radially inward from the inner ground contact edge, and an extension portion extending axially inward from the inner ground contact edge on the ground contact surface.

[0049] [Invention 3] the inner side portion has a parting line extending in the tire circumferential direction formed by a mold for forming the tire, The tire according to claim 2, wherein the main body portion is provided at a position including the parting line.

[0050] [Invention 4] The tire according to invention 2 or 3, wherein the axially inner end of the extension portion is located within a range of 5% of the tread contact width TW from the inner ground contact edge Ti.

[0051] [Invention 5] 5. The tire according to any one of inventions 1 to 4, wherein the height of the serration region in the tire radial direction is 50% or more of the cross-sectional height of the tire.

[0052] [Invention 6] 6. The tire according to any one of claims 1 to 5, wherein each of the plurality of ridges extends linearly.

[0053] [Invention 7] 6. The tire according to any one of claims 1 to 5, wherein each of the plurality of ridges includes a curved portion.

[0054] [Invention 8] A tire according to invention 7, wherein the length along each of the plurality of ridges is 200% or less of the straight-line distance connecting the start point and end point of each of the plurality of ridges.

[0055] [Invention 9] the plurality of ridges protrude outward in the tire axial direction from a side reference plane that defines a profile of the inner side portion, 9. The tire according to any one of claims 1 to 8, wherein the total surface area of ​​the plurality of ridges is 130% or more of the reference area of ​​the serration region of the side reference surface.

[0056] [Invention 10] each of the plurality of ridges has a top surface extending along the side reference surface; 10. The tire according to claim 9, wherein the total area of ​​the top faces of the plurality of ridges is 50% or less of the reference area.

[0057] [Invention 11] The inner side portion includes a sidewall rubber, The tire according to invention 9 or 10, wherein the maximum height of each of the plurality of ridges from the side reference plane is 70% or less of the maximum thickness of the sidewall rubber.

[0058] [Invention 12] the side reference surface is curved in the tire meridian cross section, 12. The tire according to any one of claims 9 to 11, wherein the curvature radius of the side reference surface is 5 mm or more. [Explanation of symbols]

[0059] 1 tire 2 Tread section 2s ground plane 3i Inner side 3o outer side 5 Ridge 6 Serration area

Claims

1. A tire that is specified for installation on a vehicle, a tread portion having a ground contact surface; an inner side portion extending radially inward from an inner side of the tread portion when the tire is mounted on a vehicle; an outer side portion extending radially inward from the vehicle-outer side of the tread portion when the tire is mounted on a vehicle, At least a portion of the inner side portion has a serration region in which a plurality of ridges are arranged in parallel, Each of the plurality of ridges extends at an angle of 45 to 90 degrees with respect to the tire circumferential direction, The outer side portion does not have the serration region. tire.

2. the ground contact surface has an inner ground contact end that defines the innermost side of the vehicle when mounted on the vehicle, 2. The tire according to claim 1, wherein the serration region includes a main body portion extending radially inward from the inner ground contact edge, and an extension portion extending axially inward from the inner ground contact edge on the ground contact surface.

3. the inner side portion has a parting line extending in the tire circumferential direction formed by a mold for vulcanizing and molding the tire, The tire according to claim 2 , wherein the main body portion is provided at a position including the parting line.

4. The tire according to claim 2 , wherein an axially inner end of the extension portion is located within a range of 5% of the tread contact width TW from an inner ground contact end Ti.

5. The tire according to claim 1 , wherein the height of the serration region in the tire radial direction is 50% or more of the section height of the tire.

6. The tire of claim 1 , wherein each of said plurality of ridges extends linearly.

7. The tire of claim 1 , wherein each of the plurality of ridges includes a curved portion.

8. The tire of claim 7 , wherein the length along each of the plurality of ridges is 200% or less of the straight-line distance connecting the start point and end point of each of the plurality of ridges.

9. the plurality of ridges protrude outward in the tire axial direction from a side reference plane that defines a profile of the inner side portion, The tire according to claim 1 , wherein a total surface area of ​​the plurality of ridges is 130% or more of a reference area of ​​the serration region of the side reference surface.

10. each of the plurality of ridges has a top surface extending along the side reference surface; 10. The tire of claim 9, wherein the total area of ​​the crest surfaces of the plurality of ridges is 50% or less of the reference area.

11. The inner side portion includes a sidewall rubber, The tire according to claim 9 , wherein the maximum height of each of the plurality of ridges from the side reference plane is 70% or less of the maximum thickness of the sidewall rubber.

12. the side reference surface is curved in the tire meridian cross section, The tire according to claim 9, wherein the radius of curvature of the side reference surface is 5 mm or more.

Images