JP2013129233A - Pneumatic tire and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire and a method for manufacturing the same, which allows improvement in visibility of a mark while reducing air drag, in a pneumatic tire with the mark provided in the sidewall part thereof and a method for manufacturing the same.SOLUTION: The pneumatic tire includes the mark 10 provided on an external surface 21 of the sidewall part 2. The mark 10 includes at least a mark element 11. Each mark element 11 is formed into a concave that is recessed relative to the external surface 21 of the sidewall part 2 and a different color rubber 12 is disposed at the inner surface of the mark element 11.

Description

  The present invention relates to a pneumatic tire and a method for manufacturing the same, and more particularly, to a pneumatic tire and a method for manufacturing the same that can improve the visibility of a mark while reducing air resistance.

  In general, on the outer surface of a sidewall portion of a pneumatic tire, a mark composed of characters, symbols, figures, and the like is engraved to display a manufacturer name, a brand name, and the like. Conventionally, as such a mark, one that protrudes high from the outer surface of the tire in order to enhance the visibility is used (for example, see Patent Document 1).

  However, the mark projecting high from the outer surface of the tire has a problem of high air resistance. Therefore, it has been proposed to use a mark recessed with respect to the outer surface of the tire instead of the mark protruding with respect to the outer surface of the tire. However, such a mark depressed with respect to the outer surface of the tire has a problem that visibility is poor compared to a mark protruding from the outer surface of the tire.

  On the other hand, a rubber having a color different from that of the rubber constituting the sidewall portion is arranged on the mark to improve visibility (see, for example, Patent Document 2). FIG. 8 shows an O-shaped mark 10 protruding from the surface 21 of the sidewall portion 2, and the surface of the mark 10 is made of a different color rubber 12 having a color different from that of the rubber 22 constituting the sidewall portion 2. It is configured. However, since such a mark 10 is molded as follows, it has an edge made of rubber 22 constituting the sidewall portion 2 at its peripheral edge. That is, as shown in FIG. 9 (A), in the green tire, a different color rubber 12 having a color different from that of the rubber 22 constituting the sidewall portion 2 is previously arranged inside the sidewall portion 2. That is, the rubber 22 is disposed on the outer surface 21 side of the sidewall portion 2 and the different color rubber 12 is disposed on the inside thereof. Next, as shown in FIG. 9B, the molded tire is vulcanized and molded so that the portion 10 'that becomes the mark 10 is raised. Thereafter, as shown in FIG. 9C, by removing the tip of the raised portion 10 ′ (the portion above the dotted line in FIG. 9B), the mark 10 with the different colored rubber 12 exposed is formed. The At this time, since the rubber 22 on the outer surface 21 side of the sidewall portion 2 remains on the side surface of the mark 10, the above-described edging is formed.

  Although such a mark is different in color from the surrounding sidewalls and can obtain excellent visibility, it is manufactured as described above, so that it does not protrude from the outer surface of the tire. The above air resistance problem is inevitable. Further, there is a problem in that productivity is poor because it is necessary to embed different color rubber in advance as described above, and material cost is increased because a large amount of different color rubber is used.

JP 2006-256432 A JP 2009-143403 A

  An object of the present invention is to solve the above-described problems, and in a pneumatic tire having a mark on a sidewall portion and a manufacturing method thereof, the visibility of the mark is improved while reducing air resistance. An object of the present invention is to provide a pneumatic tire and a manufacturing method thereof.

  In order to achieve the above object, the pneumatic tire of the present invention is a pneumatic tire in which a mark is provided on an outer surface of a sidewall portion, wherein the mark includes at least one display element, and each of the display elements is It is comprised by the recessed part depressed with respect to the outer surface of the said side wall part, and different color rubber is arrange | positioned at the inner surface of this display element, It is characterized by the above-mentioned.

  In addition, a method for manufacturing a pneumatic tire according to the present invention for achieving the above object is a method for manufacturing the above pneumatic tire, which includes at least the mark in a region where the mark is provided on the green tire. A hollow portion for forming a raised portion raised from the outer surface of the side wall portion in the molded tire, and an inner portion of the hollow portion. The green tire is vulcanized and molded with a mold having a protrusion for forming a mark that is recessed with respect to the outer surface of the sidewall portion in the molded tire, and then in the molded tire after vulcanization It is characterized by forming a mark recessed from the outer surface of the tire by scraping the raised portion.

  In the pneumatic tire according to the present invention, the display element constituting the mark provided on the outer surface of the sidewall portion is constituted by a recessed portion that is recessed with respect to the outer surface of the sidewall portion, thereby reducing air resistance. I can do it. On the other hand, since the different color rubber is disposed on the inner surface of the display element, visibility can be improved.

  In the present invention, it is preferable to form a serration formed of an array of ridges having at least two inclined surfaces with different angles on the bottom surface of the display element. By providing serrations in this manner, when the light hits the tire, a shadow is generated and the mark is emphasized, so that the visibility of the mark can be further improved.

  In the present invention, it is preferable that the depth D from the outer surface of the sidewall portion of the display element is 0.3 mm to 3.0 mm. By defining the depth D of the display element in this way, the visibility of the mark can be further enhanced.

  In the present invention, the height H from the bottom surface of the display element of the serration is set to 30% to 60% of the depth D from the outer surface of the sidewall portion of the display element, and the apex of the ridge constituting the serration It is preferable that the pitch P is 0.3 mm to 1.5 mm, and the ridges forming the serration are formed in a straight line inclined in the range of 30 ° to 60 ° with respect to the tire radial direction. By specifying the serration form in this way, an appropriate shadow is generated when light hits the tire, and an appropriate shadow is generated regardless of the incident angle of the light. Can be improved.

  In the present invention, it is preferable to use a white or yellow rubber having a different color from the rubber constituting the sidewall portion as the different color rubber. By specifying the color of the different color rubber in this way, the visibility of the mark can be further improved from the comparison with the rubber of the sidewall portion around the mark.

  In the present invention, it is preferable to provide a plurality of marks and to change the color of the different color rubber for each mark. By determining the color of the mark in this way, the visibility of the mark can be further enhanced from the comparison of each of the plurality of marks.

  On the other hand, according to the method for manufacturing a pneumatic tire of the present invention, it is only necessary to dispose a different color rubber on the green tire as described above. There is no need to embed in the wall portion, and the effect of improving the visibility of the mark can be obtained without impeding productivity. Further, as described above, the different color rubber only needs to have a size including at least the mark, so that it is possible to effectively improve the visibility of the mark while suppressing the amount of the different color rubber used. Become.

It is a meridian half section view of the pneumatic tire which consists of an embodiment of the present invention. 1 is a side view of a pneumatic tire according to an embodiment of the present invention. It is a front view which expands and shows an example of the display element which comprises the mark of this invention. It is AA arrow sectional drawing of FIG. It is a front view which expands and shows the other example of the display element which comprises the mark of this invention. It is BB arrow sectional drawing of FIG. It is explanatory drawing which shows the manufacturing method of the mark of this invention corresponding to the AA arrow sectional drawing of FIG. It is a front view which expands and shows an example of the display element which comprises the conventional mark. It is explanatory drawing which shows the manufacturing method of the conventional mark corresponding to CC sectional view taken on the line of FIG.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a pneumatic tire according to an embodiment of the present invention. In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A single carcass layer 4 is mounted between the pair of left and right bead portions 3 and 3, and end portions of these carcass layers 4 are folded around the bead core 5 from the tire inner side to the outer side. A bead filler 6 having a triangular cross section made of rubber is disposed on the outer peripheral side of the bead core 5. On the outer peripheral side of the carcass layer 4 in the tread portion 1, two belt layers 7 are arranged over the entire tire circumference. These belt layers 7 include reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers.

  The present invention is applied to such a general pneumatic tire, but its specific structure is not limited to the basic structure described above.

  In the present invention, in such a pneumatic tire, a mark 10 made up of characters, symbols, figures and the like is provided on the outer surface of the sidewall portion 2. As shown in FIG. 2, the mark 10 includes at least one display element 11. In the example of FIG. 2, the marks 10 including a plurality of display elements 11 are provided at two locations. Here, the display element 11 means characters, symbols, figures, etc. constituting the mark 10 itself. That is, in the example shown in FIG. 2, the characters “Y”, “O”, “K”, “H”, “A”, “M” included in the mark 10 including the character string “YOKOHAMA” are displayed. Each is a display element 11, and each of the characters “A”, “B”, “C”, “D”, and “E” included in the mark 10 composed of a character string “ABCDE” is a display element 11. is there.

  As shown in FIGS. 3 and 4, each of the display elements 11 is constituted by a recessed portion that is recessed with respect to the outer surface 21 of the sidewall portion 2. Also, a different color rubber 12 colored in a color different from that of the surrounding rubber 22 is disposed on the inner surface of the display element 11. In particular, since different colored rubber is disposed on the entire inner surface of the display element 11, as shown in FIGS. 3 and 4, the peripheral edge of the display element 11 (the boundary between the outer surface 21 of the sidewall portion 2 and the recess). A contour line made of the different color rubber 12 is formed in the. 3 and 4 are enlarged views of the character “O” included in the mark 10 including the character string “YOKOHAMA” shown in FIG.

  As described above, the pneumatic tire of the present invention is configured by the concave portion in which the display element 11 constituting the mark 10 provided on the outer surface 21 of the sidewall portion 2 is recessed with respect to the outer surface 21 of the sidewall portion 2. Therefore, air resistance can be reduced as compared with the mark 10 (see FIG. 9C) protruding from the outer surface 21 of the conventional sidewall portion 2. Further, since the different colored rubber 12 having a color different from that of the surrounding rubber 22 is arranged on the inner surface of the display element 11, the visibility of the mark 10 can be improved.

  The depth D from the outer surface 21 of the sidewall portion 2 of the display element 11 is preferably in the range of 0.3 mm to 3.0 mm. By defining the depth D of the display element 11 in this way, the visibility of the mark 10 can be further enhanced. At this time, if the depth D of the display element 11 is smaller than 0.3 mm, there is almost no difference in height from the outer surface 21 of the sidewall portion 2, so the effect of improving the visibility is lowered. On the contrary, if the depth D of the display element 11 is larger than 3.0 mm, the rubber gauge at the portion where the mark 10 is provided becomes too thin, and the strength of the tire becomes insufficient.

  In the present invention, in the display element 11 described above, as shown in FIGS. 5 and 6, serrations 13 formed of an array of ridges having at least two inclined surfaces with different angles on the bottom surface 11b of the display element 11 are provided. It is preferable to form. By providing the serrations 13 in this way, when the light hits the tire, a shadow is generated and the mark 10 is emphasized, so that the visibility of the mark 10 can be further improved. Even when the serrations 13 are provided in this way, as shown in FIG. 6, there is a portion where the different colored rubber 12 located on the side wall surface of the display element 11 (concave portion) is exposed on the outer surface 21 side of the side wall portion 2. Therefore, as shown in FIGS. 5 and 6, the different color rubber colored in a color different from that of the peripheral rubber 22 at the peripheral edge of the display element 11 (the boundary between the outer surface 21 and the concave portion of the side wall 2). An outline consisting of 12 is formed. 5 and 6 are enlarged views of the character “O” included in the mark 10 including the character string “YOKOHAMA” shown in FIG.

  Even when the serrations 13 are provided in this way, the depth D from the outer surface 21 of the sidewall portion 2 of the display element 11 is preferably in the range of 0.3 mm to 3.0 mm, and the visibility of the mark 10 is improved. Further enhancing effect can be obtained. At this time, if the depth D of the display element 11 is smaller than 0.3 mm, there is almost no difference in height from the outer surface 21 of the sidewall portion 2, so that the effect of improving visibility is lowered. On the contrary, if the depth D of the display element 11 is larger than 3.0 mm, the rubber gauge at the portion where the mark 10 is provided becomes too thin, and the strength of the tire becomes insufficient. The depth D of the display element 11 when the serration 13 is provided is a depth from the outer surface 21 of the sidewall portion 2 of the display element 11 to the bottom surface 11b of the display element 11.

  Further, when the serration 13 is provided, the height H of the serration 13 from the bottom surface 11b of the display element 11 is set to 30% to 60% of the depth D of the display element 11, and between the apexes of the ridges constituting the serration 13 The pitch P is 0.3 mm to 1.5 mm, and the ridges forming the serrations 13 are formed in a linear shape that is inclined with respect to the tire radial direction Z, and the inclination angle θ is in the range of 30 ° to 60 °. It is preferable. By specifying the form of the serrations 13 in this way, an appropriate shadow is generated when the tire is exposed to light, and an appropriate shadow is generated regardless of the incident angle of the light. Can be further improved.

  At this time, if the height H of the serration 13 is smaller than 30% of the depth D of the display element 11, a sufficient shadow will not be generated when the tire is exposed to light, so that the visibility of the mark 10 is improved. Decreases. On the contrary, if the height H of the serration 13 is larger than 60% of the depth D of the display element 11, the effect of improving the visibility of the mark 10 is lowered due to excessive shading. Also, if the pitch P between the ridges of the ridges constituting the serrations 13 is smaller than 0.3 mm, the serrations 13 become too fine, and when the tires are exposed to light, they are overshadowed and the visibility of the mark 10 The effect of improving is reduced. On the contrary, if the pitch P between the ridges constituting the serration 13 is larger than 1.5 mm, the serration 13 is too rough, and no sufficient shadow is generated when the tire is exposed to light. The effect of improving the property is reduced. Further, when the inclination angle θ of the ridge of the serration 13 is smaller than 30 °, sufficient shadow does not occur when light enters the tire radial direction, and the effect of improving the visibility of the mark 10 is reduced. On the contrary, when the inclination angle θ of the ridge of the serration 13 is larger than 60 °, sufficient shadow is not generated when the light is incident in the direction perpendicular to the tire radial direction, and the effect of improving the visibility of the mark 10 is lowered. To do.

  In the present invention, the color of the different color rubber 12 may be any color as long as the color is different from that of the rubber 22 constituting the sidewall portion 2, but is preferably white or yellow. . As a result, the color difference between the rubber 22 and the different color rubber 12 constituting the sidewall portion 2 that is generally black is clarified, and the visibility of the mark 10 can be further improved from these comparisons. .

  Moreover, in this invention, as shown in FIG. 2, when providing the mark 10 in multiple places, it is preferable to change the color of the different color rubber 12 for every mark. That is, in the example of FIG. 2, two kinds of different colored rubbers 12 are respectively attached so that the color of the mark 10 consisting of the character string “YOKOHAMA” and the mark 10 consisting of the character string “ABCDE” are different. It is preferable to use it for the mark 10. By determining the color of the mark 10 in this way, the visibility of the mark 10 can be further enhanced from the comparison of each of the plurality of marks 10.

  When three or more kinds of marks 10 are provided, it is not necessary that all the different color rubbers 12 have different colors as long as the color of the different color rubbers 12 is different for each mark. Moreover, it is preferable that the adjacent marks 10 are made of different colored rubbers 12 having different colors.

  The mark 10 as described above can be manufactured as follows. First, as shown in FIG. 7A, in the region where the mark 10 is to be provided on the green tire T, the different color rubber 12 having a size including at least the mark 10 to be provided is placed. The green tire T is composed of rubber 22 (rubber 22 constituting the sidewall portion 2 in the molded tire), and this rubber 22 is generally black. It is a rubber with a different color. Next, as shown in FIG. 7B, at least a region where the different color rubber 12 is disposed on the green tire T is configured as a raised portion 30 that is raised with respect to the outer surface 21 of the sidewall portion 2 in the molded tire. A recess 30 'for the purpose and a protrusion 10' for constituting the mark 10 which is located inside the recess 30 'and is recessed with respect to the outer surface 21 of the sidewall 2 in the molded tire. The green tire T is vulcanized and molded using the mold M it has. Thereafter, as shown in FIG. 7 (C), the raised portion 30 (the portion above the dotted line in FIG. 7 (B)) is scraped off from the vulcanized molded tire T ′ so as to be more than the outer surface 21 of the sidewall portion 2. A recessed mark 10 can be formed. Since the mark 10 of the present invention is manufactured in this way, the different color rubber 12 is also disposed on the side wall surface thereof, and the peripheral portion of the mark 10 (the outer surface 21 and the concave portion of the side wall portion 2). A contour line made of the different color rubber 12 is formed at the boundary.

  According to this manufacturing method, it is only necessary to dispose the different color rubber 12 on the green tire T as described above, and the rubber on the outer surface 21 side of the sidewall portion 2 like a conventional mark in which the different color rubber 12 is disposed. Since there is no need to embed different color rubber 12 inside 22, the effect of improving the visibility of the mark can be obtained without impeding productivity. Moreover, since the different color rubber 12 should just have the magnitude | size which includes the mark 10 at least as mentioned above, compared with the mark 10 which has arrange | positioned the different color rubber 12 conventionally, the usage-amount of different color rubber 12 is reduced. However, the visibility of the mark 10 can be effectively improved. Furthermore, in the mark 10 in which the different color rubber 12 is disposed as in the prior art, the rubber 22 on the outer surface 21 side of the sidewall portion 2 is disposed in the peripheral portion because of its manufacturing method. In Chapter 10, since the different color rubber 12 is disposed at the peripheral edge, the visibility can be further improved.

  In the pneumatic tire of tire size 195 / 65R15, the basic structure of the tire is made common in FIG. 1, the form of the mark provided on the sidewall portion, the presence / absence of different color rubber, the position of the different color rubber, the presence / absence of serration, Conventional example 1-2, comparative example 1, practice in which chapter depth D, serration height H, serration pitch P, serration angle θ, the number of marks, and the color of the different colored rubber of the mark are different. 24 types of test tires of Examples 1 to 21 were produced.

  The visibility of these 24 types of test tires was evaluated by the following evaluation method, and the results are also shown in Table 1.

Visibility The visibility of the mark of each test tire was visually evaluated. The evaluation results are “1” for those that do not notice the mark unless they are consciously aware, “2” for those that can confirm the presence of the mark without being conscious, but are invisible 3 if the mark is noticeable even if it is not, 4 if the content of the mark remains in the head without being conscious, and the content of the mark remains in the head without being conscious In addition, it is shown in five stages, with “5” being the impression that is impressed as a colored tire. If the evaluation is “3” or more, the visibility is excellent, and the evaluation of “4” or more is particularly preferable because the visibility is excellent.

  As can be seen from Table 1, Examples 1 to 21 were able to improve the visibility compared to Conventional Examples 1 and 2 that did not use different color rubber. Moreover, although the comparative example 1 which used the different color rubber for the mark protruding from the surface of the sidewall portion has improved visibility, it is not shown in the table, but the mark protrudes from the surface of the sidewall portion. Therefore, there is a problem that the air resistance is large.

  Among Examples 1-21, the example (Example 2, 4, 5, 8, 9, 12, 13, 16, 17) which made the dimension of the mark and the serration into the preferable range obtains more excellent visibility. I was able to do it. Furthermore, in Example 21 in which a plurality of marks were provided and the colors of the different colored rubbers of these marks were different from each other, particularly excellent visibility could be obtained.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 10 Mark 11 Display element 12 Dissimilar rubber 13 Serration

Claims (7)

In a pneumatic tire with a mark on the outer surface of the sidewall,
The mark includes at least one display element, each of the display elements is configured by a recess recessed with respect to the outer surface of the sidewall portion, and different color rubber is disposed on the inner surface of the display element. A pneumatic tire characterized by that.   2. The pneumatic tire according to claim 1, wherein a serration formed of an array of ridges having at least two inclined surfaces having different angles is formed on a bottom surface of the display element.   The pneumatic tire according to claim 1 or 2, wherein a depth D of the display element from an outer surface of the sidewall portion is set to 0.3 mm to 3.0 mm.   The height H of the serration from the bottom surface of the display element is set to 30% to 60% of the depth D from the outer surface of the sidewall portion of the display element, and between the apexes of the ridges constituting the serration The pitch P is set to 0.3 mm to 1.5 mm, and the ridge constituting the serration is formed in a straight line inclined in a range of 30 ° to 60 ° with respect to the tire radial direction. 3. The pneumatic tire according to 3.   The pneumatic tire according to any one of claims 1 to 4, wherein a white or yellow rubber having a different color from the rubber constituting the sidewall portion is used as the different color rubber.   The pneumatic tire according to any one of claims 1 to 5, wherein a plurality of the marks are provided, and the color of the different color rubber is changed in units of the marks.   A method for producing a pneumatic tire according to any one of claims 1 to 6, wherein a different color rubber having a size including at least the mark is placed in a region where the mark is provided on the green tire, and at least green A recessed portion for forming a region where the different color rubber on the tire is arranged as a raised portion raised with respect to the outer surface of the sidewall portion in the molded tire, and an outside of the sidewall portion in the molded tire located inside the recessed portion. The green tire is vulcanized and molded with a mold having a projection for forming a concave mark on the surface, and then the raised portion is scraped off from the tire outer surface in the molded tire after vulcanization. A method of manufacturing a pneumatic tire, characterized by forming a recessed mark.

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