JP2015093659A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire of which visibility is improved for wear progress degree of a tire tread.SOLUTION: A pattern D is formed at least on an inner wall 28X on a vehicle attachment inside of a circumferential groove 28 on a vehicle attachment outermost side. The pattern D is at least any of a recess or a protrusion formed on the inner wall 28X. The recess and the protrusion have anisotropy at least at any of tire circumferential direction and tire radial direction.

Description

  The present invention relates to a pneumatic tire with improved visibility regarding the degree of wear progress of a tire tread.

  In general, a wear indicator is formed on the pneumatic tire, and the wear limit can be recognized by the wear indicator appearing on the tread surface. As a pneumatic tire in which a wear indicator is formed, for example, a technique in which the groove bottom shape of the wear indicator in the tire circumferential direction is improved (see, for example, Patent Document 1).

Japanese Patent No. 4442039

  Since the wear indicator is usually formed at the groove bottom, it is not easy to confirm, and therefore, there is a possibility that the wear progress degree of the tire tread cannot be sufficiently recognized depending on the wear indicator.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the pneumatic tire which improved visibility about the abrasion progress of a tire tread.

  The pneumatic tire according to the present invention is a pneumatic tire in which at least one circumferential groove is disposed in a tread portion. A pattern is formed at least on the inner wall of the vehicle mounting inner side of the circumferential groove on the outermost side of the vehicle mounting. The said pattern is at least any one of the recessed part and convex part which were formed in the said inner wall. The concave and convex portions have anisotropy in at least one of the tire circumferential direction and the tire radial direction.

  In the pneumatic tire according to the present invention, it is possible to improve visibility of the degree of wear progress of the tire tread by forming an easily visible pattern at a position that is easy for the user to see when the vehicle is mounted.

FIG. 1 is a perspective view showing a tread portion of a pneumatic tire according to an embodiment of the present invention. 2A and 2B show the indented portion of FIG. 1, in which FIG. 2A is a tire meridian cross-sectional view, and FIG. 2B is a cross-sectional view parallel to the tire equatorial plane. FIG. 3 is a cross-sectional view parallel to the tire equatorial plane of a pneumatic tire, showing a modification of the basic form, (a) is an example in which a plurality of patterns of the same type are formed, and (b) is a pattern of different types. This is an example of formation. FIG. 4 is a cross-sectional view parallel to the tire equatorial plane showing a preferred example of the rounded portion of FIG. FIG. 5 is a tire meridian cross-sectional view showing a preferred example of the rounded portion in FIG. 1.

  Hereinafter, embodiments of the pneumatic tire according to the present invention (basic modes and additional modes 1 to 4 shown below) will be described in detail with reference to the drawings. Note that these embodiments do not limit the present invention. In addition, the constituent elements of the above embodiment include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Furthermore, various forms included in the above-described embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Basic form]
Below, the basic form is demonstrated about the pneumatic tire which concerns on this invention. In the following description, the tire radial direction means a direction orthogonal to the rotational axis of the pneumatic tire, the tire radial inner side is the side toward the rotational axis in the tire radial direction, and the tire radial outer side is in the tire radial direction. The side away from the rotation axis. The tire circumferential direction refers to a circumferential direction with the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction is the side toward the tire equator plane (tire equator line) in the tire width direction, and the outer side in the tire width direction is in the tire width direction. The side away from the tire equator. The tire equator plane is a plane that is orthogonal to the rotational axis of the pneumatic tire and passes through the center of the tire width of the pneumatic tire.

  FIG. 1 is a perspective view showing a tread portion of a pneumatic tire according to an embodiment of the present invention. The pneumatic tire 1 shown in the figure is attached to a prescribed rim (not shown) to which a prescribed internal pressure is applied, and is in an unloaded state. Here, the prescribed rim means “applied rim” prescribed in JATMA, “Design Rim” prescribed in TRA, or “Measuring Rim” prescribed in ETRTO. The specified internal pressure means “maximum air pressure” specified by JATMA, “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified by TRA, or “INFLATION PRESSURES” specified by ETRTO.

  On the surface (tread surface 12) of the tread portion 10 shown in FIG. 1, a groove 24 is provided from the groove 14 on the vehicle mounting inner side, and a groove 26 to a groove 34 is provided on the outer side of the vehicle mounting. Here, the vehicle mounting inner side refers to the vehicle side from the tire equator plane CL, and the vehicle mounting outer side refers to the side opposite to the vehicle from the tire equator plane CL. In the example shown in the figure, the vehicle is positioned on the right side of the pneumatic tire 1 when the vehicle is mounted.

  On the vehicle mounting inner side, the first circumferential main groove 14 is disposed on the outer side in the tire width direction of the tire equatorial plane CL, and on the outer side in the tire width direction of the first circumferential main groove 14 than the first circumferential main groove 14. A narrow circumferential narrow groove 16 is provided. In addition, inclined grooves 18, 20, 22 extending at an incline with respect to the tire circumferential direction from at least one of the first circumferential main groove 14 and the circumferential narrow groove 16 are respectively arranged at a predetermined pitch in the tire circumferential direction. It is installed. Further, lug grooves 24 extending in the tire width direction from the circumferential narrow grooves 16 are arranged at a predetermined pitch in the tire circumferential direction.

  On the outside of the vehicle, the second circumferential main groove 26 is disposed on the outer side in the tire width direction of the tire equatorial plane CL, and is the same as the second circumferential main groove 26 on the outer side in the tire width direction of the second circumferential main groove 26. A third circumferential main groove 28 having a width is provided. In addition, inclined grooves 30 and 32 extending at an inclination with respect to the tire circumferential direction from at least one of the second circumferential main groove 26 and the third circumferential main groove 28 are respectively arranged at a predetermined pitch in the tire circumferential direction. It is installed. Further, lug grooves 34 extending substantially in the tire width direction in the land portion on the outer side in the tire width direction of the third circumferential main groove 28 have a predetermined pitch in the tire circumferential direction with both ends terminated in the land portion. It is arranged.

  Each of the first circumferential main groove 14 disposed on the inner side of the vehicle and the second main direction main groove 26 and the third circumferential main groove 28 disposed on the outer side of the vehicle are both worn indicators 14a. , 26a, and 28a are formed. However, in the present embodiment, these wear indicators 14a, 26a, 28a may not be formed.

  FIG. 2 shows the vicinity of the region where the wear indicator 28a is formed (the rounded portion) of the third circumferential groove 28 on the outermost side of the vehicle shown in FIG. 1, where (a) is the tire with the rounded portion. It is a meridional sectional view, and (b) is a sectional view parallel to the tire equatorial plane of the rounded portion (view of the groove wall on the inner side in the tire width direction of the third circumferential main groove 28).

  As shown in FIG. 1, on the premise that the groove 34 is provided from the groove 14 on the tread surface 12, in this embodiment, as shown in FIG. A pattern D is formed on the inner wall 28 </ b> X on the vehicle mounting inner side of the three-circumferential main groove 28.

  The pattern D is at least one of a concave portion and a convex portion formed on the inner wall 28X, or a convex portion in the example shown in FIG. That is, in the present embodiment, as shown in FIG. 2A, the pattern D is a convex portion that protrudes outward in the tire width direction from the inner wall 28X.

  Moreover, the recessed part and convex part (convex part in the example shown in FIG. 2) which comprise a pattern have anisotropy in at least any one of a tire circumferential direction and a tire radial direction. Here, having anisotropy in the tire circumferential direction (tire radial direction) means that the pattern is asymmetric on both sides of the center position in the tire circumferential direction (tire radial direction). In the present embodiment, as shown in FIG. 2B, the pattern D is a figure forming the shape of an automobile, and has anisotropy in both the tire circumferential direction and the diamond radial direction. In the present embodiment, as shown in FIG. 2B, the pattern is a line visually recognized as a character, a figure, a symbol, and any combination thereof in a cross-sectional view parallel to the tire equatorial plane. Means the figure.

  In the present embodiment, the circumferential groove in which the pattern is formed is not limited to the groove that extends in the tire circumferential direction and is formed in an annular shape. For example, meandering at an angle of ± 45 ° at the maximum with respect to the tire circumferential direction and extending at an angle of ± 45 ° at the maximum with respect to a groove formed in an annular shape in the tire circumferential direction or in the tire circumferential direction Also included are grooves that terminate in the land at both ends.

(Action etc.)
In the pneumatic tire according to the present embodiment, as shown in FIG. 1 and FIG. 2, a third circumferential main groove that is at least a position that is easy for the user to see when wearing the vehicle, that is, a circumferential groove on the outermost side of the vehicle wearing. A pattern D is formed on the inner wall 28 </ b> X on the vehicle mounting side 28 of the vehicle. Further, as shown in FIG. 2B, the pattern D is an automobile pattern and has anisotropy in the tire circumferential direction and the diamond radial direction, and is simply a rectangle, square, circle, or the like. Unlike simple figures, it is a figure that can be easily recognized as an uncommon shape by the user and is easily noticeable. Therefore, according to the present embodiment, the wear progress of the tire tread can be instantly visually recognized without the user looking at the wear indicator. In the example illustrated in FIG. 1, the pattern D is formed only on the inner wall 28 </ b> X on the vehicle mounting side of the third circumferential main groove 28 on the outermost vehicle mounting. However, in the present embodiment, a pattern can be formed on the inner wall of at least one of the other grooves 14, 16, and 26 extending in the circumferential direction along with the inner wall 28X.

  In addition, although not shown in figure, the pneumatic tire which concerns on this Embodiment shown above has the same meridional cross-sectional shape as the conventional pneumatic tire. Here, the meridional cross-sectional shape of the pneumatic tire refers to a cross-sectional shape of the pneumatic tire that appears on a plane perpendicular to the tire equatorial plane. The pneumatic tire according to the present embodiment has a bead portion, a sidewall portion, a shoulder portion, and a tread portion from the inner side in the tire radial direction toward the outer side in a tire meridian cross-sectional view. The pneumatic tire includes, for example, a carcass layer extending from a tread portion to bead portions on both sides and wound around a pair of bead cores in a tire meridional section, and a tire radial outside of the carcass layer. The belt layer and the belt reinforcing layer are sequentially formed.

  In addition, the pneumatic tire of the present embodiment includes normal manufacturing processes, that is, a tire material mixing process, a tire material processing process, a green tire molding process, a vulcanization process, and an inspection process after vulcanization. It is obtained through the process. When manufacturing the pneumatic tire of the present embodiment, in particular, a concave portion corresponding to the outer surface of the pattern D shown in FIG. 2 is formed on the inner wall of the vulcanizing mold, and this mold is used for the addition. Sulfur is performed. In addition, when the pattern D consists of a recessed part, the convex part corresponding to the said recessed part is formed in the inner wall of a vulcanization metal mold | die, and vulcanization | cure is performed using this metal mold | die.

(Modification of basic form)
FIG. 3 is a cross-sectional view parallel to the tire equatorial plane of a pneumatic tire showing a modification of the basic form. The example shown in FIG. 6A is an example in which a plurality of patterns of the same type are arranged on the inner wall 28X, that is, an example in which three similar automobile patterns D1, D2, and D3 are arranged in the tire circumferential direction. The degree of wear progress can be easily visually recognized by the size of the pattern of the automobile remaining on the inner wall 28X. Note that 20% wear, 50% wear and 80% wear, which are indices shown in FIG. 3 (a), indicate that the tire new time is 0% wear and the outermost portion in the tire radial direction of the wear indicator 28a is It is an index showing the degree of progress of wear when the exposure time is 100% wear. Further, also in the case where the wear indicator 28a is not formed, each wear progress degree when the wear indicator 28a is formed is applied.

  The example shown in FIG. 3B is an example in which different patterns are arranged on the inner wall 28X, that is, an example in which a snow pattern D4 and an automobile pattern D5 are arranged in the tire radial direction. When the innermost position in the tire radial direction of the region where the snow pattern D4 is formed is set to a position corresponding to 50% wear as shown in FIG. 3B, the example shown in FIG. It serves as an index that can be used as a so-called winter tire. Normally, in winter tires, the platform indicating the above index is formed on the groove bottom, but in the example shown in FIG. 3B, the pattern may be formed on the groove wall that is more easily visible to the groove bottom. Therefore, the visibility of the progress of wear of the winter tire can be improved. Note that the interpretation of 50% wear, which is the index shown in FIG. 3B, is the same as the interpretation of the index shown in FIG.

[Additional form]
Next, additional embodiments 1 to 4 that can be optionally implemented with respect to the basic embodiment of the pneumatic tire according to the present invention will be described.

(Additional form 1)
In the basic configuration, as shown in FIG. 4 (a cross-sectional view parallel to the tire equatorial plane showing a preferred example of the rounded portion in FIG. 1), in the circumferential groove (third circumferential main groove 28). The tire circumferential dimension L of the pattern D on which the wear indicator 28a is formed, and the dimension δL of the tire circumferential direction area on which the wear indicator 28a of the pattern D is formed satisfy the relationship δL / L ≧ 0.5. (Additional form 1) is preferred. In the present embodiment, the wear indicator 28a is an essential component.

  The wear indicator is formed in the groove forming the pattern, and more than half of the tire circumferential direction area of the pattern is overlapped with the tire circumferential direction area of the wear indicator, so that the pattern and the wear indicator can be visually recognized as a single area. it can. In general, a specific area is easier to visually recognize than a smaller area. For this reason, by forming both the pattern and the wear indicator, it becomes easier for the user to visually recognize the pattern than when only the pattern is formed, and thus the visibility of the progress of wear of the tire tread is further increased. Can be improved.

(Additional form 2)
In the basic form and the form in which the additional form 1 is added to the basic form, as shown in FIG. 4, the effective groove depth H of the circumferential groove (third circumferential main groove 28), and the tire radial direction of the pattern It is preferable that the dimension δH satisfies the relationship δH / H ≧ 0.2 (additional form 2).

  Here, the effective depth H of the circumferential groove refers to the tire radial direction of the wear indicator from the tire surface when the pneumatic tire is mounted on a specified rim and is applied with a specified internal pressure and a pneumatic tire is unloaded. It means the shortest distance to the outermost part.

  The effective groove depth H of the circumferential groove forming the pattern (the third circumferential main groove 28 in the example shown in FIG. 1) and the tire radial dimension δH of the pattern satisfy the relationship of δH / H ≧ 0.2. By satisfy | filling, the tire radial direction dimension of the pattern D can fully be ensured with respect to the inner wall 28X of the groove | channel 28. FIG. Thereby, it becomes easier for the user to visually recognize the pattern, and as a result, the visibility of the progress of wear of the tire tread can be further improved. In addition, also when the wear indicator 28a is not formed, the wear progress degree when the wear indicator 28a is formed shall be applied.

(Additional form 3)
In the basic form and the form obtained by adding at least one of the additional forms 1 and 2 to the basic form, an example is shown in FIG. 5 (a tire meridian cross-sectional view showing a preferred example of the rounded portion in FIG. 1). In addition, it is preferable that the depression amount of the concave portion and the protruding amount of the convex portion (the protruding amount in the example shown in FIG. 5) from the profile surface of the inner wall 28X are 0.5 mm or more and 1.0 mm or less (additional form 3). .

  Here, the depression amount of the concave portion and the protrusion amount of the convex portion from the profile surface of the inner wall 28X mean the dimension M of the concave portion (convex portion) measured in a direction perpendicular to the profile surface of the inner wall 28X. In FIG. 5, only the protrusion amount of the convex portion is shown.

  In FIG. 5, the protrusion M from the profile surface of the inner wall 28X is set to 0.5 mm or more, so that even when foreign matter (for example, mud) adheres to the inner wall 28X, Can stand out from the part. As a result, it becomes easier for the user to visually recognize the pattern, and the visibility of the progress of wear of the tire tread can be further improved. Although not shown, the above-described effect can also be obtained when the amount of recesses recessed from the profile surface of the inner wall 28X is 0.5 mm or more.

  Moreover, in FIG. 5, the volume of the groove | channel 28 is fully ensured and the drainage performance can be improved by the protrusion amount M of the convex part from the profile surface of the inner wall 28X being 1.0 mm or less. Although not shown in the figure, the amount of recesses recessed from the profile surface of the inner wall 28X is set to 1.0 mm or less, thereby increasing the rigidity of the tread portion 10 without excessively increasing the volume of the groove 28 and improving the steering stability performance. Can be improved.

(Additional form 4)
In the basic form and the form obtained by adding at least one of the additional forms 1 to 3 to the basic form, in each of FIGS. 2 (b), 3 (a), 3 (b), and 4, the pattern D and It is preferable that the color attribute is different between the inner wall 28X on which the pattern D is formed (additional form 4).

  By making the color attributes different between the pattern D and the inner wall 28X on which the pattern D is formed, a difference in visual characteristics (contrast) can be sufficiently given to the pattern D and the inner wall 28X. As a result, it becomes easier for the user to visually recognize the pattern, and the visibility of the progress of wear of the tire tread can be further improved.

  Here, the following example is given as an aspect in which the color attribute is different between the pattern D and the inner wall 28X on which the pattern D is formed.

  That is, among the color attributes, as an aspect in which the brightness is varied, there is an aspect in which white rubber having an extremely small amount of carbon black is used in a portion of the tread rubber where the pattern D is formed when the green tire is molded. In addition, as another aspect in which the lightness is made different, there is an aspect in which a paint having a high lightness (for example, white) is applied to a portion of the tread rubber that becomes the pattern D after vulcanization.

  In addition, among the color attributes, as an aspect in which the luminance is varied, there is an aspect in which minute unevenness is formed on the pattern D by performing knurling or the like on the portion of the tread rubber that becomes the pattern D after vulcanization.

  In any of the above aspects, at least one of the color attributes (brightness or luminance) can be made different, and as a result, the pattern D and the inner wall 28X are sufficiently contrasted to wear the tire tread. The visibility regarding the degree of progress can be further improved.

  Examples 1 to 5 in which the tire size is 215 / 60R17, the tread pattern shown in FIG. 1 is provided, and 20 patterns D shown in FIGS. 2A and 2B are formed at the same pitch in the tire circumferential direction. A pneumatic tire was prepared. In these pneumatic tires, the effective depth H of the circumferential groove is 8.1 mm, and the ratio L / δH between the circumferential length L of the pattern D and the tire radial dimension δH of the pattern D is 1.5. did.

  The wear indicator was not formed for the pneumatic tire of Example 1, but was formed for the pneumatic tires of Examples 2 to 5. Various conditions regarding the pneumatic tires of Examples 1 to 7 are as shown in Table 1 below.

  On the other hand, the pneumatic tire of Example 1 except that the tire size is 215 / 60R17 and the pattern D shown in FIGS. 2A and 2B is not formed and the wear indicator is formed. The same conventional pneumatic tire as in Example 1 was produced.

Thus was prepared, and the pneumatic tire of Example 5 from Example 1, a pneumatic tire of a conventional example (each test tire), assembled in air pressure 230kPa the rim of ^{6 _1/2} J, minivan emissions 2400CC Attached to a type vehicle, the visibility of the progress of tread wear was evaluated, and the drainage performance was evaluated. The results are also shown in Table 1.

(Evaluation on visibility of tread wear progress)
After running the above vehicle equipped with each test tire for 15000 km, 20 users 160 cm to 180 cm tall looked at the groove wall where the pattern was formed at a position 1 m away from the tire to determine the degree of tread wear. Observed whether it could be recognized.

Specifically, the evaluation value when the degree of tread wear can be instantly recognized by less than 50% of the 20 users is 100 (reference value), and 50% or more of the 20 users. The evaluation value was 102 when the observer was able to instantly recognize the degree of tread wear. Of the 20 users, 60% or more, 70% or more, 80% or more, 90%
The evaluation values when the tread wear level can be instantly recognized by the above and 95% or more of the observers are 104, 106, 108, 110, and 112, respectively. This evaluation indicates that the greater the index, the better the visibility of the progress of the tread wear. The results are also shown in Table 1.

(Evaluation of drainage performance)
The vehicle equipped with each test tire was entered into a pool with a water depth of 10 mm at different speeds, and the hydroplaning generation speed by the test driver was measured. And based on this measurement result, the index evaluation which made the conventional example the standard (100) was performed. This evaluation indicates that the higher the index, the higher the hydroplaning performance. The results are also shown in Table 1.

  According to Table 1, all of the pneumatic tires of Examples 1 to 5 belonging to the technical scope of the present invention (formed with a pattern that is easily visible to the user when mounted on the vehicle), It can be seen that the visibility of the progress of the tread wear is improved as compared with the conventional pneumatic tire which does not belong to the technical scope of the present invention.

  The present invention includes the following aspects.

(1) In a pneumatic tire in which at least one circumferential groove is disposed in the tread portion, a pattern is formed on an inner wall of the vehicle mounting inner side of at least the circumferential groove on the outermost vehicle mounting. A pneumatic tire characterized in that it is at least one of a concave portion and a convex portion formed on an inner wall, and the concave portion and the convex portion have anisotropy in at least one of a tire circumferential direction and a tire radial direction.

(2) A wear indicator is formed in the circumferential groove, and a tire circumferential dimension L of the pattern and a tire circumferential direction dimension δL in which the wear indicator of the pattern is formed are δL / L The pneumatic tire according to (1), which satisfies a relationship of ≧ 0.5.

(3) The air according to (1) or (2), wherein the effective groove depth H of the circumferential groove and the tire radial dimension δH of the pattern satisfy a relationship of δH / H ≧ 0.2. Enter tire.

(4) The depression amount of the concave portion and the protrusion amount of the convex portion from the profile surface of the inner wall are 0.5 mm or more and 1.0 mm or less, according to any one of (1) to (3) above. Pneumatic tires.

(5) The pneumatic tire according to any one of (1) to (4), wherein the pattern and the inner wall on which the pattern is formed have different color attributes.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 10 Tread part 12 Tread surface 14 1st circumferential direction main groove 14a, 26a, 28a Wear indicator 16 Circumferential direction narrow groove 18, 20, 22, 30, 32 Inclined groove 24, 34 Lug groove 26 2nd circumferential direction Main groove 28 Third circumferential main groove 28X Inner wall CL Tire equatorial plane D, D1, D2, D3, D4, D5 Pattern H Effective depth L Length of pattern D in the circumferential direction M Convex portion from profile surface of inner wall 28X Protrusion δH Tire radial dimension of pattern δL Pattern D tire radial dimension

Claims (5)

In the pneumatic tire in which at least one circumferential groove is disposed in the tread portion,
A pattern is formed on the inner wall of the vehicle mounting inner side of at least the circumferential groove on the outermost vehicle mounting,
The pattern is at least one of a concave portion and a convex portion formed on the inner wall,
The pneumatic tire according to claim 1, wherein the concave portion and the convex portion have anisotropy in at least one of a tire circumferential direction and a tire radial direction. A wear indicator is formed in the circumferential groove, and a tire circumferential dimension L of the pattern and a tire circumferential region dimension δL in which the wear indicator of the pattern is formed,
δL / L ≧ 0.5
The pneumatic tire according to claim 1, satisfying the relationship: The effective groove depth H of the circumferential groove and the tire radial direction dimension δH of the pattern are:
δH / H ≧ 0.2
The pneumatic tire according to claim 1 or 2, satisfying the relationship:   The pneumatic tire according to any one of claims 1 to 3, wherein a depression amount of the concave portion and a protrusion amount of the convex portion from the profile surface of the inner wall are 0.5 mm or more and 1.0 mm or less.   The pneumatic tire according to any one of claims 1 to 4, wherein a color attribute is different between the pattern and an inner wall on which the pattern is formed.

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