Tire

Abstract

To provide a tire including a plurality of display articles on an external surface of a side wall part, and manufactured through a step of polishing the surfaces of the display articles, which can equalize the heights of the plurality of display articles after polishing, making the external appearance excellent.SOLUTION: A tire includes a plurality of display articles 10 on an external surface of a side wall part 2, and has a different color from that of the external surface of the side wall part 2 due to that at least a part of a top face of a protrusion 11 constituting at least a contour part of characters, patterns or marks described by the display articles 10 exposes different colored rubber buried in a part of the side wall part 2. When groups of the series of the display articles 10 adjacent in the tire circumferential direction are defied as character strings 20, a gap between the display articles 10 adjacent in the tire circumferential direction is constituted by a first projection surface 21 more bulged than the external surface of the side wall part 2, and a bulging height h1 of the first projection surface 21 is set to 0.1 time to 0.3 time of a bulging height H of the display article 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a tire having indicia depicting letters, figures, or symbols on the outer surface of the sidewall portion. [Background technology]

[0002] Indicia for displaying the manufacturer's name, brand name, etc., may be formed on the outer surface of the sidewall of a tire. In particular, in order to improve the visibility and decorativeness of these indicators, they are formed using a different-colored rubber (e.g., white rubber) that is a different color from the color of the sidewall (generally black) (so-called "white letters"). When manufacturing such tires, at least a portion of the portion corresponding to the sidewall of a green tire (the portion corresponding to the indicator) is formed into a laminated structure of a different-colored rubber layer (white rubber layer) and a cover rubber layer (black rubber layer) that covers the different-colored rubber layer, the green tire is vulcanized, and the indicators are formed as protrusions protruding from the surface of the sidewall. The surface of the protrusions (cover rubber layer) is then polished and removed to expose the white rubber layer, thereby forming the indicators made of different-colored rubber (see, for example, Patent Document 1).

[0003] In such tires, the process of polishing the surface of the indicia (protrusions) is carried out using a dedicated polishing machine (buffing machine) or the like. This machine rotates a polishing body (such as a grindstone) against the side of the tire, which is mounted on a stand and rotates, and polishes the tire's sidewall (indicia) in the thickness direction (the direction of the protrusion height of the protrusions) at intervals preset for each type of tire, polishing so as to expose the embedded rubber of a different color on the tire surface (see, for example, Patent Document 2). When performing the polishing process (buffing process) with such a machine, it is difficult to uniformly polish the amount of polishing (protrusion height) of each indicia included in the string, particularly when polishing (buffing) a string of characters consisting of multiple indicia, which can result in a deterioration in the appearance of the indicia (character string) after polishing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-114732 [Patent Document 2] Japanese Patent Application Publication No. 05-277925 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a tire that has a plurality of markings depicting letters, figures, or symbols on the outer surface of the sidewall portion and is manufactured through a process of polishing the surface of these markings, in which the raised height of the plurality of markings after polishing is made uniform, thereby making it possible to improve the appearance of the tire. [Means for solving the problem]

[0006] In order to achieve the above object, the tire of the present invention comprises a tread portion extending circumferentially and forming an annular shape, and a pair of sidewall portions disposed on either side of the tread portion, and the outer surface of the sidewall portion is formed with a plurality of indicia depicting at least the outline of letters, figures, or symbols by the shape of the top faces of protrusions protruding from the outer surface of the sidewall portion, and at least a portion of the top faces of the protrusions constituting each of the plurality of indicia have a different color from the outer surface of the sidewall portion by exposing different-colored rubber embedded in a portion of the sidewall portion, and is characterized in that, when a group of a series of indicia among the plurality of indicia, in which the circumferential spacing between adjacent indicia among the plurality of indicia is defined as a character string, the space between adjacent indicia in the tire circumferential direction is formed by a first protruding surface that is protruding higher than the outer surface of the portion of the sidewall portion that does not have the indicia, and the protruding height h1 of the first protruding surface is 0.1 to 0.3 times the protruding height H of the indicia. [Effects of the Invention]

[0007] The present inventors conducted extensive research into the poor appearance of indicia in tires manufactured through a process of polishing the surfaces of the protruding portions that make up the indicia. As a result, they discovered that low rigidity of the protruding portions causes the protruding portions to collapse during buffing, preventing the surface (the top surface of the indicia depicting letters, figures, or symbols) from being polished uniformly, and that, particularly when polishing a string of characters consisting of multiple indicia, differences in rigidity between the protruding portions tend to result in uneven raised heights between the protruding portions after polishing. The present invention is based on this discovery, and provides a tire with a tire having a tire-circumferentially adjacent indicia formed between first protruding surfaces that are raised higher than the outer surface of the portion of the sidewall that does not have indicia, with the raised height h1 of the first protruding surface set to 0.1 to 0.3 times the raised height H of the indicia. This increases the rigidity of each protruding portion and suppresses the difference in rigidity between the protruding portions, preventing the protruding portions from collapsing during polishing (buffing). This makes it possible to uniform the raised height of multiple indicia after polishing and improve the tire's appearance.

[0008] In this invention, for the sake of convenience, a group of a plurality of display objects in which the circumferential spacing between adjacent display objects is less than 20 mm is defined as a "character string." However, since a display object depicts characters, figures, or symbols, a group of characters, a group of figures, a group of symbols, or a group of display objects that combines these all fall under the category of a "character string."

[0009] In the present invention, the indicia include recesses surrounded by protrusions, so that the protrusions form the contour, and the recesses are formed by second protruding surfaces that are raised higher than the outer surface of the sidewall portion that does not have the indicia, and it is preferable that the raised height h2 of the second protruding surface is 0.1 to 0.3 times the raised height H of the indicia. This increases the rigidity of the individual protrusions, making the raised height of the multiple indicia uniform after polishing, which is advantageous for improving the appearance.

[0010] In the present invention, it is preferable that the protrusion height h1 of the first protruding surface and the protrusion height h2 of the second protruding surface satisfy the relationship h1≦h2, which allows the rigidity of the convex portions to be increased in a balanced manner, and is advantageous in making the protrusion heights of multiple display objects uniform after polishing and improving their appearance.

[0011] In the present invention, the portion of the convex portion adjacent to the first protruding surface side is defined as the adjacent portion, and when the length of the marker along the tire radial direction is L, the inclination angle Y1 formed by the wall surface of the adjacent portion with respect to the normal to the top surface of the adjacent portion can be set to a range of 10° to 30° within a range of 60% or more of the length L on both sides of the tire radial direction from the center position of the marker in the tire radial direction. In this specification, the wall surface angle of the adjacent portion is appropriately large, which can increase the rigidity of the adjacent portion and is advantageous for making the raised height of multiple markers uniform after polishing and improving their appearance.

[0012] In the present invention, the portion of the convex portion adjacent to the first protruding surface is defined as the adjacent portion, and when the length of the marker along the tire radial direction is L, the wall surface of the adjacent portion smoothly connects to the first protruding surface via a connecting portion having an arc-shaped cross section in a range of 60% or more of the length L on both sides of the tire radial direction from the tire radial center position of the marker, and the radius of curvature R1 of the connecting portion of the adjacent portion can be specified to be in the range of 2 mm to 4 mm. In this specification, a suitably large radius of curvature of the connecting portion can increase the rigidity of the adjacent portion, which is advantageous for making the raised height of multiple markers uniform after polishing and improving their appearance. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment of the present invention. [Figure 2] 1A and 1B are explanatory diagrams schematically showing the state of a display object before and after polishing. [Figure 3] 1 is a schematic diagram showing an example of a display object (character string) according to an embodiment of the present invention. [Figure 4] 1 is an explanatory diagram schematically illustrating a display object according to an embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram schematically illustrating a display object according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

[0015] When the tire of the present invention is a pneumatic tire as shown in FIG. 1 , it comprises a tread portion 1 that contacts the road surface, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged radially inward of the sidewall portions 2. In FIG. 1 , the symbol CL denotes the tire equator, and the symbol E denotes the ground-contact edge. Although not depicted in FIG. 1 because it is a meridian cross-section, the tread portion 1, sidewall portions 2, and bead portions 3 each extend in the tire circumferential direction and form an annular shape, thereby constituting the basic toroidal structure of a pneumatic tire. The following explanation using FIG. 1 is basically based on the meridian cross-section shape shown, but each tire component extends in the tire circumferential direction and forms an annular shape.

[0016] A carcass layer 4 is installed between a pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction and folded back from the inner side to the outer side in the tire width direction around a bead core 5 arranged in each bead portion 3. A bead filler 6 is arranged on the outer periphery of the bead core 5, and this bead filler 6 is wrapped by the main portion and folded back portion of the carcass layer 4. Meanwhile, a plurality of belt layers 7 (two layers in FIG. 1 ) are embedded on the outer periphery of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set, for example, in the range of 10° to 40°. Furthermore, at least one belt reinforcing layer 8 (two layers in FIG. 1 ) is provided on the outer periphery of the belt layer 7. The belt reinforcing layer 8 includes organic fiber cords oriented in the tire circumferential direction. In the belt reinforcing layer 8, the organic fiber cords are set at an angle of, for example, 0° to 5° with respect to the tire circumferential direction.

[0017] As described below, the present invention relates to indicia formed on the surface of the tire sidewall portion 2, and therefore the basic structure (internal structure) of the tire is not limited to the general structure described above. Furthermore, the following description will be based on a pneumatic tire (a tire filled with air, an inert gas such as nitrogen, or other gases) as shown in Fig. 1 etc., but the present invention can be applied to various tires, including non-pneumatic tires, as long as the tire has indicia depicting letters, figures, or symbols on the outer surface of the sidewall portion and is manufactured through a process of polishing the surface of the indicia.

[0018] In the present invention, as shown in Figure 1, a display 10 is provided on the outer surface of at least one of the pair of sidewall portions 2. The display 10 depicts letters, figures, or symbols using the shape of the top surfaces of protrusions 11 that protrude from the outer surfaces of the sidewall portions 2. The display 10 of the present invention has a different color from the outer surfaces of the sidewall portions by exposing different-colored rubber 12 embedded in part of the sidewall portions 2 at least in part of the top surfaces of the protrusions 11 that make up the display 10. Since the outer surfaces of tire sidewall portions are generally black, it is preferable that the different-colored rubber be white rubber from the standpoints of visibility and decorativeness.

[0019] More specifically, the protrusion 11 constituting the marker 10 is formed as a laminate of different-colored rubber 12 embedded in the sidewall portion 2 and a cover rubber 13 covering the different-colored rubber 12, as shown in FIG. 2(a). Then, by polishing and removing the surface of this protrusion 11 (the cover rubber 13 and a part of the different-colored rubber 12), the different-colored rubber 12 is exposed as shown in FIG. 2(b), and the marker 10 is formed with at least a part of the top surface of the marker 10 being made of the different-colored rubber 12. Note that FIG. 2(b) shows the state where the area above the dashed line in FIG. 2(a) has been polished and removed. Because it is manufactured as described above, strictly speaking, the top surface of the protrusion 11 of the present invention is made of the different-colored rubber 12 except for the peripheral portion derived from the cover rubber 13.

[0020] In the present invention, as shown in FIG. 3 , a plurality of the above-described display objects 10 are provided, and these plurality of display objects 10 form a character string 20. The character string 20 is a group of a series of display objects 10 among the plurality of display objects 10, in which the circumferential distance between adjacent display objects 10 is less than 20 mm. For example, in the example of FIG. 3 , a character string 20 consisting of 10 circles and a character string 20 consisting of four triangles are provided. These two types of character strings 20 are interpreted as different character strings 20 because the distance between the former (group of circles) and the latter (group of triangles) (the distance between the latter-most display object 10 included in the former character string 20 and the former-most display object 10 included in the latter character string 20) is 20 mm or more. The circumferential distance between adjacent display objects 10 is measured at the center position of the display objects 10 in the tire radial direction.

[0021] In the character string 20 described above, the space between adjacent indicia 10 in the tire circumferential direction is formed by a first protruding surface 21 that is raised higher than the outer surface of the portion of the sidewall portion 2 that does not include the indicia 10. For example, FIG. 4 illustrates two indicia 10 (the letters "Y" and "O") that are included in the character string 20 and adjacent to each other in the tire circumferential direction. FIG. 4 combines a front view of the indicia 10 with a cross-sectional view taken along the line XX. In this example, in the region between a line connecting the innermost indicia 10 in the tire radial direction and extending along the tire circumferential direction, and a line connecting the outermost indicia 10 in the tire radial direction and extending along the tire circumferential direction, the portion sandwiched between the pair of indicia 10 (the shaded portion in the figure) is configured to be raised as a first protruding surface 21 higher than the outer surface of the portion of the sidewall portion 2 that does not include the indicia 10. Note that in the cross-sectional view at the bottom of FIG. 4, no other indicia 10 is provided to the left of the letter "Y," and this portion is depicted as the outer surface of the portion of the sidewall portion 2 that does not include the indicia 10. On the other hand, to the right of the letter "O" in the drawing, a first protruding surface 21 is depicted as including an indicia 10 (not shown).

[0022] When providing the first protruding surface 21 as described above, the protruding height h1 of the first protruding surface 21 is set to 0.1 to 0.3 times the protruding height H of the marker 10. The protruding height h1 of the first protruding surface 21 is measured based on the outer surface of the portion of the sidewall portion 2 that does not have the marker 10. Similarly, the protruding height H of the marker 10 is the height from the outer surface of the portion of the sidewall portion 2 that does not have the marker 10 to the top surface 11a of the marker 10.

[0023] As described above, by providing first protruding surfaces 21 between circumferentially adjacent indicia 10 in character strings 20 and setting the raised height h1 of these first protruding surfaces 21 to 0.1 to 0.3 times the raised height H of the indicia, the rigidity of each protruding portion 11 is increased and the difference in rigidity between the protruding portions 11 is suppressed, preventing the protruding portions 11 from collapsing during polishing (buffing). This makes it possible to make the raised heights of the plurality of indicia after polishing uniform and improve their appearance. In this case, if the raised height h1 of the first protruding surfaces 21 is less than 0.1 times the raised height H of the indicia, the first protruding surfaces 21 do not substantially protrude, and therefore it is not possible to prevent the protruding portions 11 from collapsing during polishing (buffing). If the protruding height h1 of the first protruding surface 21 exceeds 0.3 times the protruding height H of the display object, the difference in protruding height between the top surface 11a of the display object 10 (the part of the display object 10 depicting letters, figures, or symbols) and the first protruding surface 21 becomes small, thereby reducing the visibility of the display object 10.

[0024] As described above, the indicia 10 depicts letters, figures, or symbols by the shape of the top surfaces 11a of the protrusions 11. However, as shown in FIG. 4, the shape of the top surfaces 11a of the protrusions 11 may depict the outline of the letters, figures, or symbols, and the letters, figures, or symbols may be depicted by the entire combination of the protrusions 11 (outline) and the recesses 22 (inside the outline) surrounded by the protrusions 11 (so-called "outline white letters"). In the illustrated example, the outline of the letter "Y" or "O" is formed by the protrusions 11 whose top surfaces 11a are made of different-colored rubber 12, and the outline (protrusions 11) and the portion surrounded by the outline (recesses 22) depict the letter "Y" or "O" as a whole. In this design, it is preferable that the recesses 22 be configured as second protruding surfaces 22 that are raised higher than the outer surface of the portion of the sidewall 2 that does not include the indicia. That is, it is preferable that the character string 20 further includes a second protruding surface 22 in addition to the first protruding surface 21 described above.

[0025] In this case, the protruding height h2 of the second protruding surface 22 is preferably 0.1 to 0.3 times the protruding height H of the marker 10. As with the protruding height h1 of the first protruding surface 21, the protruding height h2 of the second protruding surface 22 is measured based on the outer surface of the portion of the sidewall portion 2 that does not have the marker 10.

[0026] By providing the second protruding surface 22 in addition to the first protruding surface 21 in this manner, the rigidity of each protruding portion 11 can be further increased, which is advantageous for making the protruding height of multiple display objects 10 uniform after polishing and improving their appearance. If the protruding height h2 of the second protruding surface 22 is less than 0.1 times the protruding height H of the display object, the second protruding surface 22 does not substantially protrude, and therefore the effect of preventing the protruding portions 11 from collapsing during polishing (buffing) is limited. If the protruding height h2 of the second protruding surface 22 exceeds 0.3 times the protruding height H of the display object, the difference in protruding height between the top surface 11a of the display object 10 (the portion of the display object 10 depicting letters, figures, or symbols) and the second protruding surface 22 becomes small, thereby reducing the visibility of the display object 10.

[0027] When providing the first protruding surface 21 and the second protruding surface 22 as described above, the protruding height h1 of the first protruding surface 21 and the protruding height h2 of the second protruding surface 22 preferably satisfy the relationship h1≦h2, and more preferably the relationship 1≦h2 / h1≦2. This allows for a balanced increase in the rigidity of the protrusion 11, which is advantageous for uniforming the protruding heights of multiple display objects after polishing and improving their appearance. If the relationship between the protruding heights h1 and h2 is reversed, the effect of providing the second protruding surface 22 will not be fully achieved.

[0028] As described above, the present invention aims to improve the rigidity of the display object 10 (protrusion 11) by providing the first protruding surface 21 and the second protruding surface 22. However, further improvement in rigidity can be achieved by adjusting the shape of the protrusion 11. For example, in the embodiment shown in FIG. 5, the portion of the protrusion 11 adjacent to the first protruding surface 21 is defined as the adjacent portion 11' (see the shaded area in FIG. 5). Let L be the length of the display object 10 along the tire radial direction. In a range of preferably at least 60%, more preferably at least 80%, of the length L on both sides of the tire radial direction from the tire radial center position of the display object 11, the inclination angle Y1 formed by the wall surface 11b of the adjacent portion 11' relative to the normal to the top surface 11a of the adjacent portion 11' is preferably in the range of 10° to 30°, more preferably 20° to 30°. In this configuration, the appropriately large wall surface angle of the adjacent portion 11' can increase the rigidity of the adjacent portion 11', which is advantageous for uniforming the raised height of multiple display objects 10 after polishing and improving their appearance. If the inclination angle Y1 is less than 10°, the wall surface angle will not be effective in improving rigidity. If the inclination angle Y1 exceeds 30°, the wall surface will be excessively inclined, which may deteriorate the appearance of the display object 10. Note that Figure 5 is a combination of a front view of the display object 10 (the protrusion 11 depicting the outline of the alphabet "G" and the recess 22 (second protruding surface 22) surrounded by this protrusion 11) and a cross-sectional view taken along the line XX.

[0029] Alternatively, in the embodiment shown in FIG. 5 , the portion of the protrusion 11 adjacent to the first protruding surface 21 is defined as the adjacent portion 11′ (see the shaded area in FIG. 5 ). Let L be the radial length of the display object 10. The wall surface 11b of the adjacent portion 11′ smoothly connects to the first protruding surface 21 via a connecting portion 11c having an arc-shaped cross section, preferably extending over at least 60%, more preferably at least 80%, of the length L from the center of the display object 10 in the radial direction of the tire. The radius of curvature R1 of the connecting portion 11c of the adjacent portion 11′ is preferably set to a range of 2 mm to 4 mm, more preferably 3 mm to 4 mm. In this configuration, a moderately large radius of curvature of the connecting portion 11c can enhance the rigidity of the adjacent portion 11′, which is advantageous for uniforming the raised height of the multiple display objects 10 after polishing and improving their appearance. If the radius of curvature R1 is less than 2 mm, the shape of the connecting portion 11c will not be effective in improving rigidity. If the radius of curvature R1 exceeds 4 mm, the range of the connection portion 11c will become wider, and the appearance of the display object 10 may deteriorate.

[0030] The above-mentioned conditions for the inclination angle Y1 and the radius of curvature R1 may be satisfied simultaneously. That is, the inclination angle Y1 of the wall surface 11b of the adjacent portion 11' may be set preferably in the range of 10° to 30°, more preferably 20° to 30°, and the radius of curvature R1 of the connecting portion 11c may be set preferably in the range of 2 mm to 4 mm, more preferably 3 mm to 4 mm. Combining the conditions in this manner effectively increases the rigidity of the connecting portion 11c, which is advantageous for making the protrusion height of the multiple display objects 10 uniform after polishing and improving their appearance.

[0031] The range in which the above-mentioned inclination angle Y1 and curvature radius R1 conditions apply is preferably 60% or more, more preferably 80% or more, of the length L from the tire radial center position of the display object 11 to both sides in the tire radial direction, where L is the length of the display object 10 along the tire radial direction, as described above. If this applicable range is less than 60% of the length L, the range in which rigidity can be improved by the inclination angle Y1 and curvature radius R1 is limited, and the effects provided by the inclination angle Y1 and curvature radius R1 are limited. The wall surface angle of the convex portion 11 in other parts (hereinafter referred to as "other parts") is not particularly limited. However, if the angle formed by the wall surface 11b of the other parts of the convex portion 11 with respect to the normal direction of the top surface 11a is defined as inclination angle Y2, then inclination angle Y1 is preferably larger than inclination angle Y2. Inclination angle Y2 is not particularly limited, but can be set to, for example, 5° to 10°. In other areas, the wall surface 11b of the protrusion 11 is preferably smoothly connected to the surface of the sidewall portion 2 and the second protruding surface 22 via a connecting portion 11c having an arc-shaped cross section, and when the radius of curvature of the connecting portion 11c is R2, the radius of curvature R1 is preferably larger than the radius of curvature R2. The radius of curvature R2 is not particularly limited, but can be set to, for example, 1 mm to 2 mm.

[0032] The present invention will be further explained below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0033] Tires were produced as Conventional Example 1, Comparative Examples 1-2, and Examples 1-8, with a tire size of 215 / 65R16C 109 / 107Q and a basic structure (internal structure) as illustrated in FIG. 1, and with regard to the structure of the markings, the presence or absence of a first protruding surface, the ratio h1 / H of the protrusion height h1 of the first protruding surface to the protrusion height H of the marking, the ratio h2 / H of the protrusion height h2 of the second protruding surface to the protrusion height H of the marking, the magnitude relationship between h1 and h2, the inclination angle Y1, the radius of curvature R1, and the applicable range of the inclination angle Y1 and / or the radius of curvature R1, as shown in Table 1.

[0034] The "Scope of Application" column in Table 1 indicates the range within which the inclination angle Y1 and / or the radius of curvature R1 are set to the values ​​listed in each column of Table 1. When the length of the display object along the tire radial direction is L, this column indicates the percentage of the length L from the tire radial center position of the display object to both sides of the tire radial direction within which the inclination angle Y1 and / or the radius of curvature R1 are applied.

[0035] In all examples, the process of polishing the surface of the display object (protrusion) was carried out by mounting each tire on a wheel with a rim size of 16 x 6.5, inflating it to an internal pressure of 200 kPa, and then mounting it on a dedicated polishing machine (buffing machine).

[0036] The uniformity of the raised height after polishing of these pneumatic tires was evaluated using the following evaluation method, and the results are also shown in Table 1.

[0037] Uniformity of protrusion height after polishing The maximum and minimum values ​​of the raised height of the markings included in the character strings formed on each tire after polishing were measured, and the difference between them was calculated as an index of the uniformity of the raised height after polishing. The evaluation results were expressed as an index using the reciprocal of the measured value, with Conventional Example 1's value set at 100. The larger the index value, the smaller the difference between the maximum and minimum values ​​of the raised height of the markings (the more uniform the raised height after polishing).

[0038] [Table 1]

[0039] As is clear from Table 1, the tires of Examples 1 to 8 were able to suppress differences in raised height after polishing, and were able to improve the surface condition of the indicia (character strings). On the other hand, Comparative Example 1 was an embodiment that did not have a first protruding surface and only had a second protruding surface (i.e., an embodiment in which only the recessed portion surrounded by the outline of the indicia (characters) was raised), so it was not possible to make the raised height after polishing sufficiently uniform. In Comparative Example 2, the raised height of the first protruding surface was too small, so the first protruding surface did not substantially raise, and the effect of making the raised height after polishing uniform was not obtained.

[0040] The present disclosure includes the following inventions. Invention [1] A tire comprising a tread portion extending in the circumferential direction of the tire and forming an annular shape, and a pair of sidewall portions disposed on both sides of the tread portion, wherein a plurality of indicia depicting at least the outline of a letter, figure, or symbol are formed on the outer surface of the sidewall portion by the shape of the top surfaces of protrusions protruding from the outer surface of the sidewall portion, and at least a portion of the top surfaces of the protrusions constituting each of the plurality of indicia have a different color from the outer surface of the sidewall portion by exposing different colored rubber embedded in a portion of the sidewall portion, When a group of the plurality of display objects in which the circumferential spacing between adjacent display objects is less than 20 mm is defined as a character string, A space between the indicia adjacent in the tire circumferential direction is formed by a first protruding surface that is raised higher than an outer surface of a portion of the sidewall portion that does not have the indicia, The tire is characterized in that the raised height h1 of the first protruding surface is 0.1 to 0.3 times the raised height H of the indicia. Invention [2] The indicia include a recess surrounded by the protrusion, so that the protrusion constitutes the contour portion, and the recess is formed by a second protruding surface that is raised higher than the outer surface of the portion of the sidewall that does not have the indicia, The tire according to invention [1], wherein the raised height h2 of the second protruding surface is 0.1 to 0.3 times the raised height H of the indicia. Invention [3] The tire according to invention [2], wherein the raised height h1 of the first protruding surface and the raised height h2 of the second protruding surface satisfy the relationship h1≦h2. Invention [4] A tire according to any one of inventions [1] to [3], wherein the portion of the convex portion adjacent to the first protruding surface side is defined as an adjacent portion, and the length of the indicia along the tire radial direction is L, and the inclination angle Y1 formed by the wall surface of the adjacent portion with respect to the normal direction of the top surface of the adjacent portion is in the range of 10° to 30° within a range of 60% or more of the length L on both sides of the tire radial direction from the tire radial center position of the indicia. Invention [5] A tire according to any one of inventions [1] to [4], wherein a portion of the convex portion adjacent to the first protruding surface side is defined as an adjacent portion, and the length of the marking object along the tire radial direction is L, and within a range of 60% or more of the length L on both sides of the tire radial direction from the tire radial center position of the marking object, the wall surface of the adjacent portion is smoothly connected to the first protruding surface via a connecting portion having an arc-shaped cross section, and the radius of curvature R1 of the connecting portion of the adjacent portion is in the range of 2 mm to 4 mm. [Explanation of symbols]

[0041] 1 Tread section 2 Sidewall 3 Bead section 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Belt reinforcement layer 10 Display items 11 Convex part 11a Wall 11b Top surface 11c Connection 20 Strings 21 First protruding surface 22 Second protruding surface (recess) CL Tire Equator E Ground end

Claims

1. A tire comprising a tread portion extending in the circumferential direction of the tire to form an annular shape, and a pair of sidewall portions disposed on both sides of the tread portion, wherein a plurality of indicia depicting at least the outline of a letter, figure, or symbol are formed on the outer surface of the sidewall portion by the shape of the top surfaces of protrusions protruding from the outer surface of the sidewall portion, and at least a portion of the top surface of the protrusions constituting each of the plurality of indicia has a color different from that of the outer surface of the sidewall portion by exposing a different color rubber embedded in a portion of the sidewall portion, When a group of the plurality of display objects in which the circumferential spacing between adjacent display objects is less than 20 mm is defined as a character string, A space between the indicia adjacent in the tire circumferential direction is formed by a first protruding surface that is raised higher than an outer surface of a portion of the sidewall portion that does not have the indicia, The tire is characterized in that the raised height h1 of the first protruding surface is 0.1 to 0.3 times the raised height H of the indicia.

2. The indicia includes a recess surrounded by the protrusion, so that the protrusion forms the contour portion, and the recess is formed by a second protruding surface that is raised higher than an outer surface of a portion of the sidewall portion that does not have the indicia, 2. The tire according to claim 1, wherein the second protruding surface has a protruding height h2 that is 0.1 to 0.3 times the protruding height H of the indicia.

3. The tire according to claim 2, wherein a protruding height h1 of the first protruding surface and a protruding height h2 of the second protruding surface satisfy the relationship h1≦h2.

4. The tire according to any one of claims 1 to 3, characterized in that, when a portion of the convex portion adjacent to the first protruding surface side is defined as an adjacent portion, and the length of the display object along the tire radial direction is L, an inclination angle Y1 formed by the wall surface of the adjacent portion with respect to the normal direction of the top surface of the adjacent portion is in a range of 10° to 30° within a range of 60% or more of the length L on both sides of the tire radial direction from the center position of the display object in the tire radial direction.

5. The tire according to any one of claims 1 to 3, characterized in that a portion of the convex portion adjacent to the first protruding surface side is defined as an adjacent portion, and when the length of the display object along the tire radial direction is L, in a range of 60% or more of the length L on both sides of the tire radial direction from the tire radial center position of the display object, the wall surface of the adjacent portion is smoothly connected to the first protruding surface via a connecting portion having an arc-shaped cross section, and the radius of curvature R1 of the connecting portion of the adjacent portion is in a range of 2 mm to 4 mm.

Images