JP5510632B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire for automobiles, for example.

  In general, this type of pneumatic tire is provided with a decorative band composed of a plurality of ridges on the outer surface of the sidewall, and each ridge is formed to extend in a straight line substantially parallel to the adjacent ridge. It is known that they are arranged at equal intervals in the direction so as to make the concavity and convexity generated on the outer surface of the sidewall during tire molding inconspicuous by the folded end portion of the carcass (for example, see Patent Document 1).

  As another pneumatic tire, a decorative band composed of a plurality of first ridges and second ridges is provided on the outer surface of the sidewall, and each first ridge is linearly parallel to the adjacent first ridge. The second ridges are formed so as to extend in a straight line substantially parallel to the adjacent second ridges, and intersect the first ridges at an angle of about 70 to 90 °. It is known that the concave and convex portions are made inconspicuous by intersecting the second ridge and the mark provided on the decorative band is made conspicuous (see, for example, Patent Document 2).

JP 2004-224342 A Japanese Patent Laid-Open No. 08-282216

  By the way, various ingenuity has been made in addition to the above-mentioned patent documents to make the unevenness generated on the outer surface of the sidewall inconspicuous at the time of tire molding and to make the mark provided on the decorative band conspicuous. Is required.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to make the unevenness generated on the outer surface of the sidewall during tire molding inconspicuous and to make the mark provided on the sidewall conspicuous. It is to provide a pneumatic tire that can be used.

For the present invention to achieve the above object, the service id wall a pneumatic tire having a decorative portion extending in a strip shape in the tire circumferential direction on the outer surface, the decorative portion, 0.8 mm or more 3.0mm or less of each other A first ridge group composed of a plurality of concentric ridges arranged so as to be arranged at substantially equal intervals at a predetermined pitch P and a second ridge group composed of ridges having the same specifications as the first ridge group are formed to overlap each other. The first ridge group and the second ridge group are arranged with a predetermined distance L shifted in the tire radial direction, and the predetermined distance L with respect to the pitch P is 10 times or more and 25 times or less. doing.

  Accordingly, the ridge group of the decorative portion includes a first ridge group including a plurality of concentric ridges arranged at substantially equal intervals with a predetermined pitch P of 0.8 mm to 3.0 mm, and A ridge group and a second ridge group composed of ridges having substantially the same specifications are formed so as to overlap each other, and the first ridge group and the second ridge group are arranged to be shifted by a predetermined distance L in the tire radial direction. On the other hand, the predetermined distance L is configured to be 10 times or more and 25 times or less, so that each ridge of the first ridge group intersects with each ridge of the second ridge group, so that a moire pattern is formed on the decorative portion. Occurs. Further, since the predetermined distance L is configured to be 10 times or more and 25 times or less with respect to the predetermined pitch P, the moire pattern is clearly shown in the decorative portion, and the thickness and interval of the interference fringes of the moire pattern are increased. The ridges of the first ridge group and the second ridge group are visually recognized so that the thicknesses and intervals of the ridges are clearly different.

  According to the pneumatic tire of the present invention, each ridge of the first ridge group intersects with each ridge of the second ridge group, so that a moire pattern is generated in the decorative portion, and the moire pattern is clearly shown. It is visually recognized that the thickness and interval of the interference fringes generated in the pattern and the thickness and interval of each ridge of the first ridge group and the second ridge group are clearly different. That is, the ridge group formed by superimposing the first ridge group and the second ridge group can make the unevenness generated on the outer surface of the sidewall during tire molding inconspicuous, and also make the unevenness inconspicuous by the moire pattern. Therefore, it is extremely advantageous to make the unevenness inconspicuous. Further, if the moiré pattern is not generated on the surface of the mark, the mark provided on the sidewall can be made conspicuous.

The front view of the pneumatic tire which shows the premise technique of this invention Front view of main parts of pneumatic tire Diagram showing the specifications of the first ridge group The figure which shows the state which piled up the 1st ridge group and the 2nd ridge group Table showing evaluation results Table showing evaluation results Table showing evaluation results Table showing evaluation results Table showing evaluation results Evaluation model example Evaluation model example Evaluation model example Front view of pneumatic tire Front view of a pneumatic tire showing a first modification of the base technology The figure which shows the state which overlap | superposed the 1st ridge group and the 2nd ridge group in the 2nd modification of a base technology The figure which shows the state which piled up the 1st ridge group and the 2nd ridge group in the 3rd modification of a base technology The front view of the pneumatic tire which shows one Embodiment of this invention Front view of main parts of pneumatic tire Diagram showing the specifications of the first ridge group The figure which shows the state which piled up the 1st ridge group and the 2nd ridge group Table showing evaluation results Table showing evaluation results Table showing evaluation results Table showing evaluation results Table showing evaluation results Table showing evaluation results The figure which shows the specification of the 1st ridge group which shows the modification of this embodiment. The figure which shows the state which piled up the 1st ridge group and the 2nd ridge group which show the modification of this embodiment Front view of a pneumatic tire showing another modification of the present embodiment Sectional drawing of the 1st ridge of this embodiment and 2nd Embodiment The principal part front view of the pneumatic tire of this embodiment

A pneumatic tire according to the premise technique of the present invention will be described with reference to FIGS. In addition, this pneumatic tire is used by being mounted on a vehicle such as a four-wheeled vehicle, a truck, or a bus.

  As shown in FIGS. 1 and 2, this pneumatic tire is provided with a decorative portion 2 in a strip shape over the entire circumference in a predetermined radial range AR on the outer surface of the sidewall 1. A group RG is provided. The ridge group RG includes a first ridge group RG1 composed of a plurality of (for example, 400) ridges R1 that are arranged at substantially equal intervals with a predetermined pitch P (for example, a pitch of 2 mm), as shown below. The first ridge group RG1 and the second ridge group RG2 including the ridge R2 having the same specifications are overlapped (see FIGS. 3 and 4). In addition, the decoration part 2 is provided with two display parts 10 representing marks by characters and figures, the characters of the display part 10 are provided so as to protrude from the surface of the sidewall 1, and the surface of the characters etc. For example, it is formed in a planar shape. The vulcanization mold is provided with unevenness corresponding to the ridge group RG and the display unit 10, and the ridge group RG and display unit 10 are engraved on the outer surface of the sidewall 1 by the unevenness.

  As shown in FIG. 3, each ridge R1 of the first ridge group RG1 is provided to extend radially from the first ridge group center C1 as the first point. In the present embodiment, the tire axis C0 and the first ridge group center C1 coincide (see FIG. 3). Moreover, as shown in FIG. 3, each ridge R1 actually appearing on the outer surface of the sidewall 1 of the tire is a portion that falls within a predetermined radial range AR among the radially extending portions. Each ridge R1 is provided so as to extend radially from the first ridge center C1. Strictly speaking, the ridges R1 are angled with each other, but the number of ridges R1 is large, and the angle formed by each ridge R1 is Since it is only slightly (around 1 °), it can be said that the ridges R1 are arranged so as to be substantially parallel to each other. As shown in FIG. 2, the pitch P of each ridge R1 is the distance between the ridges R1 on the tire inner diameter side within the predetermined radial range AR. Since each ridge R1 is provided so as to extend radially from the first ridge center C1, each ridge R1 is arranged point-symmetrically with respect to the first ridge group center C1.

  Each ridge R2 of the second ridge group RG2 is composed of a plurality of (for example, 400) ridges R2 having the same specifications as the first ridge group RG1, and each ridge R2 is defined as a second point as shown in FIGS. The second ridge group center C2 is provided to extend radially. Further, as shown in FIG. 4, the second ridge group center C2 is arranged at a position shifted in the tire radial direction by a predetermined distance L from the first ridge group center C1. Moreover, as shown in FIG. 3, each ridge R2 actually appearing on the outer surface of the sidewall 1 of the tire is a portion that falls within a predetermined radial range AR among the radially extending portions. Each ridge R2 is provided so as to extend radially from the second ridge center C2. Therefore, strictly speaking, the ridges R2 are angled with each other, but the number of ridges R2 is large, and the angle formed by each ridge R2 is Since it is only slightly (around 1 °), it can be said that the ridges R2 are arranged so as to be substantially parallel to each other. As shown in FIG. 2, the pitch P2 of each ridge R2 is the distance between the ridges R2 on the inner side in the tire radial direction within the predetermined radial range AR, and the pitch P2 of each ridge R2 is the pitch P of each ridge R1. Is equivalent to In addition, since each ridge R2 is provided so as to extend radially from the second ridge center C2, each ridge R2 is arranged point-symmetrically with respect to the second ridge group center C2.

  Thus, since this pneumatic tire has the ridge group RG formed by superimposing the first ridge group RG1 and the second ridge group RG2 on the decorative portion 2 of the sidewall 1, the pitch P and the By setting the predetermined distance L, a moire pattern is generated in the decorative portion 2.

  Here, the applicant evaluated the relationship between the amount of pitch P of each ridge R1 of the first ridge group RG1 and the amount of the predetermined distance L and the occurrence of moire patterns (see FIGS. 5 to 10). . As shown in FIGS. 11 and 12, the evaluation of FIGS. 5 to 8 was performed by creating a figure in which the ridge group RG was provided on the decorative portion 2 having an inner diameter of 300 mm and an outer diameter of 400 mm. The observer evaluated the visibility of the moiré pattern, and also evaluated the presence or absence of differences in the appearance of the ridges R1 and R2 of the ridges R1 and R2 in the thickness and interval of the moire pattern interference fringes IS. The evaluation in FIG. 9 was performed by creating a diagram in which the ridge group RG was provided on the decorative portion 2 having an inner diameter of 400 mm and an outer diameter of 500 mm, and the same evaluation was performed. Furthermore, the evaluation of FIG. 10 was performed by creating a diagram in which the ridge group RG was provided on the decorative portion 2 having an inner diameter of 600 mm and an outer diameter of 700 mm, and the same evaluation was performed.

  Regarding the visibility of the moire pattern, when the moiré pattern is judged to be clearly visible by 95% or more of the observers, the evaluation is 104, and when the moire pattern is judged to be clearly visible by 80% or more of the observers The evaluation is 102, and the evaluation is 100 when it is judged that the moire pattern can be clearly seen by 60% or more of the observers, and the evaluation is given when the moire pattern is clearly seen by the observers of less than 60% Is 98. In addition, regarding the presence or absence of a difference in appearance with respect to the thickness and interval of each of the ridges R1 and R2 in the thickness and interval of the moire pattern interference fringes IS, when the difference is determined to be clear by 95% or more observers The evaluation is 104, the evaluation is 102 when the difference is determined to be clear by 80% or more of the observers, and the evaluation is 100 when the difference is determined by the 60% or more of the observers. If the difference is judged to be clear by less than 60% of observers, the rating is 98. Moreover, since the pitch P is set in the range of 0.8 mm to 3.0 mm in an actual tire, the pitch P is changed in the range of 0.8 mm to 3.0 mm as shown in FIGS. Evaluation was performed.

  5 to 8, the ratio (L / P) of the predetermined distance L to the pitch P, the visibility of the moire pattern, and the thickness and interval of the interference fringes IS of the moire pattern with respect to the thickness and interval of the ridges R1 and R2. It has been found that there is a correlation between the difference (the difference between Moire and Ridge). It was also found that the correlation between L / P and each evaluation result was the same for any pitch P.

  From FIG. 5 to FIG. 10, in the range where L / P is 10 times or more and 25 times or less, the evaluation result of the visibility of the moire pattern is 102 or more, and the evaluation result of the presence or absence of the difference is 102 or more. In addition, in the range where L / P was 10 times or more and 20 times or less, the evaluation result of the visibility of the moire pattern was 104, and the evaluation result of the presence or absence of the difference was 104. That is, in the range where L / P is 10 times or more and 25 times or less, the evaluation result of the visibility of the moire pattern and the evaluation result of the difference are good, and in the range where L / P is 10 times or more and 20 times or less. Further, it has been found that the evaluation result of the visibility of the moire pattern and the evaluation result of the difference are further favorable.

  Furthermore, except for the evaluation result of FIG. 8 when the inner diameter is 300 mm or more and 400 mm or less and the pitch P is 3 mm, the evaluation result of the visibility of the moire pattern is 104 in the range where L / P is 10 times or more and 25 times or less. became. That is, when the inner diameter is 300 mm or more, the pitch P is in the range of 0.8 mm or more and 2.5 mm or less, and when the inner diameter is 400 mm or more, the pitch P is in the range of 0.8 mm or more and 3.0 mm or less. It becomes good.

As described above , according to the pneumatic tire , the first ridge group RG1 including the plurality of ridges R1 arranged so as to be arranged at substantially equal intervals with a predetermined pitch P of 0.8 mm or more and 3.0 mm or less; The ridge group RG of the decoration portion 2 is formed by superimposing the first ridge group RG1 and the second ridge group RG2 made of the ridge R2 of the same specification, and the first ridge group RG1 and the second ridge group RG2 are tires. If the predetermined distance L is shifted in the radial direction by a predetermined distance L and the predetermined distance L is 10 times or more and 25 times or less with respect to the predetermined pitch P, a moire pattern appears clearly in the decorative portion 2. The thickness and interval of the moire pattern interference fringes IS and the thickness and interval of each ridge of the first ridge group RG1 and the second ridge group RG2 are visually recognized so as to be clearly different. That is, the ridge group RG formed by superimposing the first ridge group RG1 and the second ridge group RG2 can make the unevenness generated on the outer surface of the sidewall 1 during tire molding inconspicuous, and the unevenness is also caused by a moire pattern. Can be made inconspicuous, which is extremely advantageous in making the unevenness inconspicuous. In addition, since the moire pattern does not occur on the surface of the character or the like of the display unit 10, the display unit 10 provided on the sidewall 1 can be made conspicuous.

Further, in the pneumatic tire , the first ridge group RG1 and the second ridge group RG2 having the same specification are shifted and overlapped in the tire radial direction, so that two ridge groups having different specifications are overlapped. In comparison, the design time can be shortened. Furthermore, even when the tire size is changed or the range of the decorative portion 2 is changed, the decorative portion 2 can be designed easily, which is extremely advantageous in reducing the design time.

Further, in the pneumatic tire , a moire pattern is clearly displayed on the decorative portion 2, and the thickness and interval of the moire pattern interference fringes IS and the thickness and interval of each ridge of the first ridge group RG1 and the second ridge group RG2. Since it is visually perceived so as to be clearly different, it is possible to give a person who observes the tire a dynamic impression, a three-dimensional impression, a powerful impression, and the like, which is extremely advantageous in characterizing the tire appearance.

  In the present embodiment, the first ridge group RG1 and the second ridge group RG2 having the same specifications are overlapped while being shifted in the tire radial direction. For this reason, as shown in FIG. 13, the moire pattern generated in the decorative portion 2 extends substantially in the shifting direction between the first ridge group RG1 and the second ridge group RG2 and is substantially a line with respect to the line SL1 passing through the tire axis C0. It becomes symmetrical and is advantageous for improving the appearance of the tire.

In the pneumatic tire , as shown in FIG. 13, the display units 10 are arranged at positions that are substantially line symmetrical with respect to the line SL <b> 1. Specifically, a line extending in the direction perpendicular to the shifting direction between the first ridge group RG1 and the second ridge group RG2 and passing through the tire axis C0 in the center position of the range where each display unit 10 is provided. Each display unit 10 is provided such that an angle α formed with SL2 is 20 ° or less. For this reason, the display part 10 and the decoration part 2 appear in harmony on the outer surface of the sidewall 1, which is extremely advantageous in improving the appearance of the tire.

In addition, although the said pneumatic tire showed what each display part 10 has arrange | positioned as shown in FIG. 13, it is also possible to provide each display part 10 as shown in FIG. In this case, each display unit 10 is provided such that an angle β formed by the center position of the range where each display unit 10 is provided and the line SL1 is 20 ° or less. In this case, even when the character size of one display unit 10 and the other display unit 10 are different, the angle β formed by the center position of the range where each display unit 10 is provided and the line SL1. If each display unit 10 is provided so that the angle is 20 ° or less, it can be said that the respective display units 10 are arranged at positions that are substantially line-symmetric with respect to the line SL2. For this reason, since the moire pattern generated in the decorative portion 2 is substantially line symmetric with respect to the line SL1, the display portion 10 and the decorative portion 2 appear in harmony on the outer surface of the sidewall 1, thereby improving the appearance of the tire. This is extremely advantageous.

In the pneumatic tire , the first ridge group RG1 and the second ridge group RG2 have the same specifications. However, if the first ridge group RG1 and the second ridge group RG2 have substantially the same specifications, It is possible to achieve the same effect as described above. For example, even when the number of ridges R1 in the first ridge group RG1 is 400 and the number of ridges R2 in the second ridge group RG2 is 380 (the number that is 95% of the number of ridges R1), the same as described above. It is possible to achieve the operational effects.

In the pneumatic tire , the first ridge group center C1 and the tire axis C0 coincide with each other. On the other hand, as shown in FIG. 15, even when the tire axial center C0 is disposed substantially at the center between the first ridge group center C1 and the second ridge group center C2, the same effect as described above can be achieved. In this case, the moire pattern generated in the decoration portion 2 is line symmetric with respect to the line SL1 and also line symmetric with respect to the line SL2, so that the tire appearance is improved and the display unit 10 is harmonized. Is very advantageous.

  Further, as shown in FIG. 16, even when the tire axial center C0 is not arranged between the first ridge group center C1 and the second ridge group center C2, the distance D to any one of the ridge group centers is When the inner diameter of the decorative portion 2 is 1/10 or less, the same effect as described above can be achieved.

In the pneumatic tire , the ridges R1 and R2 of the ridge groups RG1 and RG2 are linear. On the other hand, even when the ridges R1 and R2 are curved, the ridges R1 extend in the radial direction and are arranged at substantially equal intervals with a predetermined pitch P of 0.8 mm to 3.0 mm. If they are arranged and each ridge R2 of the second ridge group RG2 has substantially the same specifications as the ridge R1 of the first ridge group RG1, the same effect as described above can be achieved.

In the pneumatic tire , the decorative portion 2 is provided with two display portions 10. However, even when other small display portions are provided at other positions of the decorative portion 2, In the case where the two display units 10 are arranged at positions that are substantially symmetrical with each other, the same operational effects as described above can be achieved.

The pneumatic tire of an embodiment of the present invention will be described with reference to FIGS. 17 to 26. This pneumatic tire is also used by being mounted on a vehicle such as a four-wheeled vehicle, a truck, or a bus, as in the above-mentioned prerequisite technology .

This pneumatic tire is obtained by changing the specifications of the first ridge group RG1 and the second ridge group RG2 in the base technology .

  That is, in this pneumatic tire, as shown in FIGS. 17 and 18, the decorative portion 2 is provided in a strip shape over the entire circumference in a predetermined radial range AR on the outer surface of the sidewall 1. Is provided with a ridge group RG. The ridge group RG includes a first ridge group RG1 composed of a plurality of concentric (for example, 25) ridges R1 arranged so as to be arranged at substantially equal intervals with each other at a predetermined pitch P (for example, 2 mm pitch). In this way, the first ridge group RG1 and the second ridge group RG2 composed of the ridge R2 having the same specifications are overlapped. In addition, the decoration part 2 is provided with two display parts 10 representing marks by characters and figures. Each character of the display part 10 is provided so as to protrude from the surface of the sidewall 1, and the surface of each character is For example, it is formed in a planar shape. The vulcanization mold is provided with unevenness corresponding to the ridge group RG and the display unit 10, and the ridge group RG and display unit 10 are engraved on the outer surface of the sidewall 1 by the unevenness.

  As shown in FIG. 19, each ridge R1 of the first ridge group RG1 has a concentric circular shape with respect to the first ridge group center C1 as the first point. In the present embodiment, the tire axial center C0 and the first ridge group center C1 coincide (see FIG. 19). Moreover, as shown in FIG. 19, each ridge R1 actually appearing on the outer surface of the sidewall 1 of the tire is a portion that falls within a predetermined radial range AR. Since each ridge R1 has a circular shape concentric with the first ridge center C1, each ridge R1 is arranged point-symmetrically with respect to the first ridge group center C1.

  Each ridge R2 of the second ridge group RG2 has the same specifications as the first ridge group RG1, and a plurality of (for example, 25) ridges R2 arranged to be arranged at substantially equal intervals with a predetermined pitch P (for example, 2 mm pitch). As shown in FIGS. 19 and 20, the ridge R2 has a circular shape concentric with the second ridge group center C2 as the second point. As shown in FIG. 20, the second ridge group center C2 is arranged at a position shifted in the tire radial direction by a predetermined distance L from the first ridge group center C1. Further, as shown in FIG. 20, each ridge R1 that actually appears on the outer surface of the sidewall 1 of the tire is a portion that falls within a predetermined radial range AR. Further, since each ridge R2 has a concentric circular shape with respect to the second ridge center C2, each ridge R2 is arranged point-symmetrically with respect to the first ridge group center C2.

  Thus, since this pneumatic tire has the ridge group RG formed by superimposing the first ridge group RG1 and the second ridge group RG2 on the decorative portion 2 of the sidewall 1, the pitch P and the By setting the predetermined distance L, a moire pattern is generated in the decorative portion 2.

Here, the applicant evaluated the relationship between the amount of pitch P of each ridge R1 of the first ridge group RG1 and the amount of the predetermined distance L and the occurrence of moire patterns (see FIGS. 21 to 26). . In the evaluation of FIGS. 21 to 24, a drawing in which the ridge group RG is provided on the decorative portion 2 having an inner diameter of 300 mm and an outer diameter of 400 mm is created, and the visibility of the moire pattern is evaluated by the 20 observers. At the same time, the presence / absence of a difference in appearance (difference between moire and ridge) with respect to the thickness and interval of each of the ridges R1 and R2 of the moire pattern interference fringes IS was evaluated. Further, the evaluation of FIG. 25 was performed by creating a figure in which the ridge group RG was provided on the decorative portion 2 having an inner diameter of 400 mm and an outer diameter of 500 mm, and the same evaluation was performed. In the evaluation of FIG. 26, a drawing in which the ridge group RG was provided on the decorative portion 2 having an inner diameter of 600 mm and an outer diameter of 700 mm was made, and the same evaluation was performed. The evaluation method is the same as that of the base technology . Moreover, since the pitch P is set in the range of 0.8 mm to 3.0 mm in an actual tire, the pitch P is changed in the range of 0.8 mm to 3.0 mm as shown in FIGS. And evaluated.

  21 to 24, the ratio (L / P) of the predetermined distance L to the pitch P, the visibility of the moire pattern, and the thickness and interval of the interference fringes IS of the moire pattern with respect to the thickness and interval of the ridges R1 and R2. It was found that there was a correlation with the difference. It was also found that the correlation between L / P and each evaluation result was the same for any pitch P.

  From FIG. 21 to FIG. 26, in the range where L / P is 10 times or more and 25 times or less, the evaluation result of the visibility of the moire pattern is 104, and the evaluation result of the presence or absence of the difference is 102 or more. In addition, in the range where L / P was 10 times or more and 20 times or less, the evaluation result of the visibility of the moire pattern was 104, and the evaluation result of the presence or absence of the difference was 104. That is, in the range where L / P is 10 times or more and 25 times or less, the evaluation result of the visibility of the moire pattern and the evaluation result of the difference are good, and in the range where L / P is 10 times or more and 20 times or less. Further, it has been found that the evaluation result of the visibility of the moire pattern and the evaluation result of the difference are further favorable.

  Furthermore, except for the evaluation result of FIG. 24 when the inner diameter is 300 mm or more and 400 mm or less and the pitch P is 3 mm, the evaluation result of the visibility of the moire pattern is 104 in the range where L / P is 10 times or more and 25 times or less. became. That is, when the inner diameter is 300 mm or more, the pitch P is in the range of 0.8 mm or more and 2.5 mm or less, and when the inner diameter is 400 mm or more, the pitch P is in the range of 0.8 mm or more and 3.0 mm or less. It becomes good.

  Thus, according to the present embodiment, the first ridge group RG1 composed of a plurality of concentric ridges R1 arranged so as to be arranged at substantially equal intervals with a predetermined pitch P of 0.8 mm to 3.0 mm. The first ridge group RG1 and the second ridge group RG2 composed of the ridge R2 having the same specifications are overlapped to form the ridge group RG of the decoration portion 2, and the first ridge group RG1 and the second ridge group RG2 Are arranged so as to be shifted by a predetermined distance L in the tire radial direction and the predetermined distance L with respect to the predetermined pitch P is configured to be 10 times or more and 25 times or less, the moire pattern is clear on the decorative portion 2. It appears that the thickness and interval of the moire pattern interference fringes IS and the ridge thickness and interval of the first ridge group RG1 and the second ridge group RG2 are clearly different. That is, the ridge group RG formed by superimposing the first ridge group RG1 and the second ridge group RG2 can make the unevenness generated on the outer surface of the sidewall 1 during tire molding inconspicuous, and the unevenness is also caused by a moire pattern. Since it can be made inconspicuous, it is extremely advantageous in making the unevenness inconspicuous. In addition, since the moire pattern does not occur on the surface of the characters of the display unit 10, the display unit 10 provided on the sidewall 1 can be made conspicuous.

In the present embodiment, the first ridge group RG1 and the second ridge group RG2 having the same specifications are overlapped while being shifted in the tire radial direction. For this reason, as in FIG. 13 of the base technology, the moire pattern generated in the decoration portion 2 extends in the shifting direction between the first ridge group RG1 and the second ridge group RG2 and passes through the tire axis C0. It is almost line symmetric. Further, since the moire pattern appears in line symmetry, by placing each display unit 10 at the same position as the base technology, it is possible to achieve the same effects as the base technology.

  In the present embodiment, the first ridge group RG1 and the second ridge group RG2 have the same specifications. However, if the first ridge group RG1 and the second ridge group RG2 have substantially the same specifications, It is possible to achieve the same effect as described above. For example, even if the pitch P of the ridge R1 of the first ridge group RG1 is 2 mm and the pitch P of the ridge R2 of the second ridge group RG2 is 1.9 mm (95% of the pitch P of the ridge R1), Similar effects can be achieved.

In the present embodiment, the first ridge group center C1 and the tire axis C0 coincide with each other. On the other hand, as in the base technology , even when the tire axial center C0 is arranged at the approximate center between the first ridge group center C1 and the second ridge group center C2, the same effect as described above can be achieved. In this case, the moire pattern generated in the decoration portion 2 is line symmetric with respect to the line SL1 and also line symmetric with respect to the line SL2, so that the tire appearance is improved and the display unit 10 is harmonized. Is very advantageous.

  Further, even when the tire axis C0 is not disposed between the first ridge group center C1 and the second ridge group center C2, the distance D to one of the ridge group centers is 1 of the inner diameter of the decorative portion 2. When it is / 10 or less, the same effect as described above can be achieved.

In the base technology , each ridge R1 of the first ridge group RG1 is provided so as to extend radially from the first ridge group center C1. On the other hand, as shown in FIG. 27, the ridges RG1 of the first ridge group RG1 are in contact with a virtual circle CIR centered on the first ridge group center C1 and are arranged at substantially equal intervals with each other at a predetermined pitch P. Even in this case, the ridges R2 of the second ridge group RG2 have substantially the same specifications as the first ridge group RG1, and the second ridge group center C2 has a predetermined distance L from the first ridge group center C1. If the pitch P, the predetermined distance L, and the L / P values are set as in the base technology , the moiré pattern appears clearly in the decorative portion 2 and the moiré pattern interference occurs. It seems that the thickness and interval of the stripes IS and the thickness and interval of each ridge of the first ridge group RG1 and the second ridge group RG2 are clearly different (see FIG. 28). If the diameter of the virtual circle CIR is 2/3 or less of the inner diameter of the decorative portion 2, the ridges R1 are in contact with the virtual circle CIR as shown in FIG. Even in this case, it can be said that each ridge R1 is formed to extend in the tire radial direction. The pitch of each ridge R1 is the distance between the ridges R1 on the tire inner diameter side within the predetermined radial range AR, as in FIG. Since each ridge R1 is a tangent line that touches a virtual circle centered on the first ridge center C1, each ridge R1 is arranged point-symmetrically with respect to the first ridge group center C1.

In the base technology and the present embodiment, the ridge group RG is provided over the entire circumference of the decorative portion 2. On the other hand, as shown in FIG. 29, the decorative portion 2 is provided in a part of the decorative portion 2 in the circumferential direction (for example, two locations in the circumferential direction), and only the first ridge group RG1 is provided in the other portion OP. It is also possible to provide other patterns or to form a flat surface. Even in this case, if the values of the pitch P, the predetermined distance L, and L / P are set as in the base technology , a moiré pattern appears clearly in the decorative portion 2, and the thickness and interval of the interference fringes IS of the moiré pattern. It appears that the thicknesses and intervals of the ridges of the first ridge group RG1 and the second ridge group RG2 are clearly different. Similarly to the above, the display units 10 are arranged at positions that are substantially line-symmetric with respect to the line SL1, or the display units 10 are arranged at positions that are substantially line-symmetric with respect to the line SL2. Thus, the moire pattern of the decorative portion 2 and each display portion 10 appear in harmony, which is extremely advantageous for improving the appearance of the tire.

In the base technology and this embodiment, a groove is provided at a position corresponding to the ridge group RG of the decorative portion 2 in the vulcanizing mold, and the ridge group RG is engraved in the decorative portion 2 by the groove. However, it is preferable that the width of the bottom portion of the groove of the vulcanizing mold is 1/3 or more and 1/2 or less with respect to the pitch of the groove. Accordingly, as shown in FIG. 30, the width W of the upper ends of the ridges R1 and R2 of the ridge groups RG1 and RG2 constituting the ridge group RG is approximately 1 / with respect to the pitch P of the ridges R1 and R2. 3 to 1/2. The first ridge group RG1 and the second ridge group RG2 have the same specifications, and the ridge group RG is formed by shifting the first ridge group RG1 and the second ridge group RG2 by a predetermined distance L in the tire radial direction. ing. That is, after forming the groove for the first ridge group RG1 in the vulcanizing mold, the groove for forming the ridge group RG is formed in the vulcanizing mold by forming the groove for the second ridge group RG2. Is done. Therefore, for example, in the base technology , the width W2 of the ridge in the vicinity where the first ridge R1 and the second ridge R2 intersect is greater than the width W1 of the ridge in the intersection or other portions. For this reason, when the ridge group RG is observed from the front, the portion of the width M1 appears mainly as moire interference fringes, but when the ridge group RG is observed from an oblique direction, the portion of the width M2 is lighter than the other portions. The portion of the width M2 appears mainly as moire interference fringes. That is, when the width W of the upper ends of the ridges R1 and R2 is approximately 1/3 or more and 1/2 or less with respect to the pitch P, different moire interference fringes depending on the observation angle can be seen. This is very advantageous for visual characterization.

DESCRIPTION OF SYMBOLS 1 ... Side wall, 2 ... Decoration part, RG ... Ridge group, RG1 ... 1st ridge group, R1 ... Ridge, RG2 ... 2nd ridge group, R2 ... Ridge, C0 ... Tire axial center, C1 ... 1st ridge center, C2 ... second ridge center, P ... predetermined pitch, L ... predetermined distance, AR ... predetermined range, IS ... interference fringes.

Claims (5)

In a pneumatic tire provided with a decorative portion extending in a belt shape in the tire circumferential direction on the outer surface of the sidewall,
The same specifications as the first ridge group and the first ridge group, which are composed of a plurality of concentric ridges arranged on the decorative portion so as to be arranged at substantially equal intervals with a predetermined pitch P of 0.8 mm or more and 3.0 mm or less. A ridge group formed by superimposing a second ridge group of ridges of
The first ridge group and the second ridge group are shifted by a predetermined distance L in the tire radial direction,
A pneumatic tire characterized in that the predetermined distance L with respect to the pitch P is 10 times or more and 25 times or less. The moiré pattern generated in the decorative portion by the intersection of the first ridge group and the second ridge group extends substantially in the direction in which the first ridge group and the second ridge group are shifted and passes through the tire axis. The pneumatic tire according to claim 1, wherein the pneumatic tire is line-symmetric. Each ridge of the first ridge group is arranged point-symmetrically with respect to the first point at the center of the first ridge group, and each ridge of the second ridge group is at the center of the second ridge group. Placed point-symmetrically with respect to the point,
The pneumatic tire according to any one of claims 1 and 2 , wherein a tire axial center is arranged at a substantially center between the first point and the second point. The decorative portion is provided with two display portions composed of a plurality of characters and figures arranged in the tire circumferential direction,
Each of the display portions is configured to be arranged at a position that is substantially line symmetrical with respect to a line that extends in a shifting direction between the first ridge group and the second ridge group and passes through the tire axis. The pneumatic tire according to any one of claims 1, 2, and 3 . The decorative portion is provided with two display portions composed of a plurality of characters and figures arranged in the tire circumferential direction,
The display units are configured to be arranged at positions that are orthogonal to the shifting direction of the first ridge group and the second ridge group and are substantially line symmetrical with respect to a line passing through the tire axis. The pneumatic tire according to any one of claims 1, 2, and 3 ,