JP5802236B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire in which a decorative pattern is formed on the surface of a sidewall portion.

  Generally, the sidewall portion of a pneumatic tire is covered with, for example, a rubber having a small thickness. For this reason, local irregularities called bulges and dents are likely to appear on the surface of the sidewall portion due to the seam of the carcass that is the internal structural material of the tire, residual air, and the like.

  Conventionally, in order to make the unevenness inconspicuous, there has been proposed a pneumatic tire in which a band-shaped decorative pattern extending along the tire circumferential direction is formed on the surface of the sidewall portion. For example, in Patent Document 1 below, as shown in FIG. 6, a curved pattern b extending in the tire radial direction and a linear pattern c having a different shape intersecting the curved pattern b are repeatedly arranged in the tire circumferential direction. A formed decorative pattern a has been proposed.

JP 2004-17828 A

  However, in recent years, in order to reduce the rolling resistance of the tire, the sidewall portion tends to be covered with a rubber having a smaller thickness. For this reason, the said unevenness | corrugation becomes easy to appear on the surface of a sidewall part, and there existed a problem that it was difficult to obtain the sufficient blinding effect which makes an unevenness | corrugation inconspicuous in the conventional decorative pattern a.

  The present invention has been devised in view of the above problems, and has as its main object to provide a pneumatic tire having a decorative pattern having a blinding effect that makes the unevenness appearing on the surface of the sidewall portion inconspicuous.

  The invention according to claim 1 of the present invention is a pneumatic tire in which a strip-shaped decorative pattern extending along the tire circumferential direction is formed on the surface of the sidewall portion, and the decorative pattern is in the tire circumferential direction. A plurality of unit patterns repeatedly arranged in the tire radial direction, each unit pattern including a central portion in the tire radial direction, an outer portion continuous to the outer side in the tire radial direction of the central portion, and an inner side in the tire radial direction of the central portion. A continuous inner part, the central part is a linear pattern, the outer part is an arc-shaped pattern that protrudes to one side in the tire circumferential direction, and the inner part is the other in the tire circumferential direction. The outer portion and the inner portion include a plurality of arc-shaped patterns having different radii of curvature, and the decorative pattern includes adjacent unit patterns in the outer portion and the inner portion. Intersect multiple intersections Seen, the central portion is a pneumatic tire characterized by having no said intersection.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein each unit pattern has a straight line connecting the inner end and the outer end in the tire radial direction located on the tire radial direction line.

  The invention according to claim 3 is the pneumatic tire according to claim 1 or 2, wherein the linear pattern has an angle of 45 ° or less with respect to a tire radial direction.

  According to a fourth aspect of the present invention, the ratio (L1 / L) between the length L of the unit pattern in the tire radial direction and the length L1 of the central portion in the tire radial direction is 0.04 to 0.19. The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is in a range of.

According to a fifth aspect of the present invention, the outer portion and the inner portion have a first arc-shaped pattern having the largest curvature radius R1, a second arc-shaped pattern having the smallest curvature radius R2 , and the first arc-shaped pattern. A third arc-shaped pattern having a radius of curvature R3 between the pattern and the second arc-shaped pattern, and a ratio of a radius of curvature R3 of the third arc-shaped pattern and a radius of curvature R1 of the first arc-shaped pattern ( R3 / R1) is in the range of 0.36 to 0.93, and the ratio (R2 / R3) between the radius of curvature R2 of the second arc-shaped pattern and the radius of curvature R3 of the third arc-shaped pattern is 0. The pneumatic tire according to any one of claims 1 to 4, which is in a range of 31 to 0.81 . In the invention according to claim 6, both end portions of the plurality of arc-shaped patterns having different curvature radii of the outer side portion are terminated at the same position of both end portions in the radial direction of the outer side portion, and 6. The pneumatic tire according to claim 1, wherein both end portions of the plurality of arc-shaped patterns having different curvature radii are terminated at the same position of both end portions in the radial direction of the inner side portion.

  The pneumatic tire of the present invention includes a plurality of unit patterns in which the decorative pattern is repeatedly arranged in the tire circumferential direction. Each unit pattern includes a central portion in the tire radial direction, an outer portion that continues to the outer side in the tire radial direction of the central portion, and an inner portion that continues to the inner side in the tire radial direction of the central portion. The central portion is a linear pattern, the outer portion is an arc-shaped pattern that is convex on one side in the tire circumferential direction, and the inner portion is an arc-shaped pattern that is convex on the other side in the tire circumferential direction. It is. Each of the outer portion and the inner portion includes a plurality of arc-shaped patterns having different curvature radii. The decorative pattern includes a plurality of intersections where adjacent unit patterns intersect in the outer portion and the inner portion, and the central portion does not have the intersection.

  The outer part and the inner part of each unit pattern are arc-shaped patterns, which are more complicated than the linear pattern at the center. Further, the decorative pattern includes a plurality of intersections at the outer side portion and the inner side portion, and the pattern density is changed. Shadows are hard to be formed in areas where the pattern density is low. On the contrary, more shadows are formed in the portion where the pattern density is high.

  Therefore, in the pneumatic tire of the present invention, the contrast effect of the decorative pattern is enhanced, the decorative pattern is made conspicuous, and the blinding effect of making unevenness such as bulges and dents in the sidewall portion inconspicuous is improved.

  Furthermore, since the outer portion and the inner portion are different from each other in the protruding direction of the arc, the light applied to the sidewall portion is reflected in different directions. For this reason, the arc-shaped pattern on the outer side and the arc-shaped pattern on the inner side are easily visually recognized as having different heights. Such an effect makes it more difficult to visually recognize the unevenness. Therefore, in the pneumatic tire of the present invention, the blinding effect can be further improved.

It is the partial side view which expanded the side of the pneumatic tire of this embodiment. It is the schematic of the AA cross section of the side wall part of FIG. It is the elements on larger scale of the decoration pattern of FIG. FIG. 4 is an enlarged plan view of the unit pattern of FIG. 3. FIG. 5 is a BB end view of FIG. 4. It is the elements on larger scale of the side wall part which shows the conventional decoration pattern.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a partial side view in which a side surface of a pneumatic tire (hereinafter may be simply described as “tire”) 1 of the present embodiment is enlarged. FIG. 2 is a tire meridian cross section including a tire rotation axis, and a schematic diagram of the AA cross section of FIG. 1 is shown.

  As shown in FIG. 1 or 2, a decorative pattern 3 is formed on the surface 2S of the sidewall portion 2 of the tire 1.

  In this specification, when there is no notice in particular, the dimension of each part of the tire 1 is a value in a normal state. The “normal state” is a state in which the tire 1 is assembled on a normal rim (not shown) and filled with a normal internal pressure and is not loaded.

  The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA and “Design Rim” for TRA. For ETRTO, "Measuring Rim".

  The “regular internal pressure” is the air pressure defined by each standard for each tire in the standard system including the standard on which the tire is based. For example, “maximum air pressure” for JATMA, “table pressure for TRA” The maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, and “INFLATION PRESSURE” in the case of ETRTO.

  The sidewall portion 2 includes, for example, a carcass 5 and a sidewall rubber 2G disposed on the outer side of the carcass 5 in the tire axial direction. A surface 2S of the sidewall portion 2 is formed of a sidewall rubber 2G.

  The decorative pattern 3 extends in a band shape along the tire circumferential direction on the surface 2S of the sidewall portion 2. The “strip shape” includes both one that continuously extends in a ring shape in the tire circumferential direction and an arc shape that forms part of the tire circumferential direction. In the present embodiment, the decorative pattern 3 is formed in an annular shape that is continuous in the tire circumferential direction, for example.

  The decorative pattern 3 is a pattern formed on the surface 2S of the sidewall rubber 2 by, for example, vulcanization molding or cutting. The decorative pattern 3 of the present embodiment is formed by, for example, vulcanization molding from the viewpoint of durability and productivity.

  For example, ribs 4 extending in the tire circumferential direction are formed on the inner side, the outer side, or both sides of the decorative pattern 3 in the tire radial direction. The rib 4 of the present embodiment includes the outer rib 4A or the inner rib 4B in order to suppress the occurrence of cracks and the like starting from both ends of the decorative pattern 3 in the tire radial direction. The outer rib 4A and the inner rib 4B each protrude outward in the tire axial direction.

  FIG. 3 shows a partially enlarged view in which the decorative pattern 3 of FIG. 1 is enlarged. As shown in FIG. 3, the decorative pattern 3 includes a plurality of unit patterns 6 that are repeatedly arranged in the tire circumferential direction.

  FIG. 4 shows an enlarged plan view in which one of the unit patterns 6 of FIG. 3 is enlarged. As shown in FIG. 3 or FIG. 4, each unit pattern 6 includes a central portion Sc in the tire radial direction, an outer portion So connected to the outer side in the tire radial direction of the central portion Sc, and a tire radial direction of the central portion Sc. It includes an inner part Si that is continuous on the inner side.

  In the unit pattern 6, the central portion Sc is a linear pattern 7, and the outer portion So is an arc-shaped pattern 8 that is convex on one side in the tire circumferential direction. The inner portion Si is an arc-shaped pattern 9 that is convex on the other side in the tire circumferential direction.

The outer portion So of the present embodiment includes a plurality of arc-shaped patterns with different curvature radii. Outer portion So of the present embodiment, for example, the most a first arcuate pattern 8A of large radius of curvature R1, the most and second arcuate pattern 8B of the small radius of curvature R2, the first arc-shaped pattern 8A and second arcuate A third arc-shaped pattern 8C having a radius of curvature R3 between the pattern 8B and the pattern 8B is included.

The inner part Si of the present embodiment includes a plurality of arc-shaped patterns having different radii of curvature, like the outer part So. Inner portion Si of the present embodiment, for example, the most a first arcuate pattern 9A of large radius of curvature R1, the most and second arcuate pattern 9B of small radius of curvature R2, the first arc-shaped pattern 9A and the second arcuate A third arc-shaped pattern 9C having a radius of curvature R3 between the pattern 9B and the pattern 9B is included.

  The linear pattern 7 and the arc-shaped patterns 8 and 9 are formed, for example, as ridges. In the unit pattern 6, the outer end Y1 of the linear pattern 7 and the inner end of the arc-shaped pattern 8 are connected. Similarly, the inner end Y2 of the linear pattern 7 and the outer end of the arc-shaped pattern 9 are connected.

  As shown in FIG. 3, the outer portion So and the inner portion Si include a plurality of intersection points P where adjacent unit patterns 6 intersect. On the other hand, the central portion Sc does not have the intersection point P.

  The outer part So and the inner part Si of each unit pattern 6 are arc-shaped patterns 8 and 9. This is a complicated shape as compared with the linear pattern 7 in the central portion Sc. Furthermore, the outer portion So and the inner portion Si include a plurality of intersection points P, and the pattern density is changed. In general, it is difficult to form a shadow in a portion having a low pattern density. On the contrary, more shadows are formed in the portion where the pattern density is high. Therefore, in the tire 1 according to the present embodiment, the contrast of the decorative pattern 3 is increased, and the decorative pattern 3 is made more conspicuous, thereby improving the blinding effect of making unevenness such as bulge and dent of the sidewall portion 2 inconspicuous. .

  Further, since the outer portion So and the inner portion Si have different arc projecting directions, the light irradiated on the sidewall portion 2 is reflected in different directions. For this reason, the arc-shaped pattern 8 of the outer part So and the arc-shaped pattern 9 of the inner part Si are easily visually recognized as having different heights. Such an effect makes it difficult to visually recognize the unevenness of the sidewall portion 2. Therefore, in the tire 1 of the present embodiment, the blinding effect can be further improved.

  As shown in FIG. 4, in each unit pattern 6, a straight line G connecting the outer end Y3 and the inner end Y4 in the tire radial direction is located on the tire radial direction line, for example. That is, when the straight line G is extended inward in the tire radial direction, it intersects the tire rotation axis. Such unit patterns 6 are arranged in a radial manner in the tire radial direction and repeatedly in the tire circumferential direction with good balance. For this reason, the decorative pattern 3 is further improved in sensitivity quality.

  If the pattern density of the linear pattern 7 in the central portion Sc is increased, the blinding effect may not be sufficiently exhibited. For this reason, it is desirable that the linear pattern 7 has an angle θ of 45 ° or less with respect to the tire radial direction, for example. Thereby, the length of the linear pattern 7 can be suppressed small, and it can suppress that a pattern density becomes high. From the same viewpoint, for example, it is desirable that the outer end Y1 of the linear pattern 7 is inclined in the tire circumferential direction in the same direction as the direction in which the arc-shaped pattern 8 protrudes in the tire circumferential direction.

  The ratio (L1 / L) between the length L of the unit pattern 3 in the tire radial direction and the length L1 of the central portion Sc in the tire radial direction is preferably in the range of 0.04 to 0.19, for example. When the value of the ratio (L1 / L) is smaller than 0.04, the central portion Sc is small, and there is a possibility that the change in the pattern density cannot be confirmed. On the contrary, when the value of the ratio (L1 / L) is larger than 0.19, when the central part Sc having a low pattern density is large and the unevenness of the sidewall part 2 occurs in the central part Sc, the blinding effect is sufficient. There is a risk that it will not be demonstrated.

  The length L2 of the outer portion So in the tire radial direction is preferably about the same as the length L3 of the inner portion Si in the tire radial direction from the viewpoint of improving the sensitivity quality of the tire 1, for example. In addition, when the length L2 of the outer portion So and the length L3 of the inner portion Si are different, for example, if the tire radial direction length L1 of the central portion Sc is within the range of the ratio (L1 / L), The same blindfold effect as that of the present embodiment can be exhibited.

  The ratio (R1 / R3) between the radius of curvature R1 of the first arc-shaped patterns 8A and 9A and the radius of curvature R3 of the third arc-shaped patterns 8C and 9C is, for example, in the range of 0.36 to 0.93. desirable. The ratio (R3 / R2) between the radius of curvature R2 of the second arc-shaped patterns 8B and 9B and the radius of curvature R3 of the third arc-shaped patterns 8C and 9C is, for example, in the range of 0.31 to 0.81. desirable. When the values of the ratio (R1 / R3) and ratio (R3 / R2) are outside the above range, the partial pattern density is excessively increased in the outer portion So and the inner portion Si, and the arc-shaped pattern 8 and 9 may be difficult to form.

  FIG. 5 shows a BB end view of FIG. As shown in FIG. 5, the height h of the ridges of the unit pattern 6 is not particularly limited, but is preferably 0.1 to 1.0 mm, for example. When the height h is less than 0.1 mm, it is difficult to visually recognize the protrusions of the unit pattern 6 on the surface 2S of the sidewall portion 2, and the blinding effect that makes the unevenness inconspicuous may not be sufficiently exhibited. On the contrary, when the height h is larger than 1.0 mm, the durability of the ridges of the unit pattern 6 is lowered, and there is a possibility that cracks may be generated starting from the ridges.

  The width W perpendicular to the longitudinal direction of the ridges of the unit pattern 6 is not particularly limited, but is preferably 0.4 to 1.5 mm, for example. When the width W is less than 0.4 mm, it is difficult to form the decorative pattern 3 and the productivity may be reduced. Conversely, if the width W exceeds 1.5 mm, the blinding effect may be reduced.

  When the decorative pattern 3 is molded by a vulcanization mold, the unit pattern 6 is formed by a groove-shaped molding portion of the vulcanization mold. Such a molded part functions as a vent line for discharging air in the mold. Therefore, it is useful for suppressing unevenness of the surface 2S of the sidewall portion 2.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to these embodiment, It can deform | transform and implement in a various aspect.

Based on the specifications in Table 1, a pneumatic tire having the decorative pattern shown in FIG. 3 was prototyped and its performance was tested. A pneumatic tire (comparative example) having the decorative pattern shown in FIG. 6 was prototyped and tested in the same manner.
The common specifications are as follows.

Tire size: 195 / 65R15
The length L of the decorative pattern in the tire radial direction: 38.5 mm
Height of linear pattern and arc-shaped pattern (projection) h: 0.3 mm
Width W of linear pattern and arc-shaped pattern (projection): 0.3 mm
Each test method is as follows.

<Blindfold performance>
In the sidewall portion of each test tire, the unevenness was confirmed with the naked eye, and the distinguishability of the unevenness was evaluated by a five-point method according to the tester's sensuality. The evaluation shows that the larger the score, the more difficult it is to identify the irregularities and the better the blinding performance.

<Molding performance>
Based on the time and cost required for the processing of each test tire, it was evaluated by the 5-point method. In the evaluation, the larger the score, the less time and cost required for processing and the better the molding performance.

  As a result of the test, it was confirmed that the tires of the examples were excellent in blindfold performance and molding performance.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Side wall part 2S Surface 3 Decoration pattern 6 Unit pattern 7 Linear pattern 8 Arc-shaped pattern 9 Arc-shaped pattern

Claims (6)

A pneumatic tire in which a band-shaped decorative pattern extending along the tire circumferential direction is formed on the surface of the sidewall portion,
The decorative pattern includes a plurality of unit patterns repeatedly arranged in the tire circumferential direction,
Each unit pattern includes a central portion in the tire radial direction, an outer portion continuous to the tire radial direction outer side of the central portion, and an inner portion continuous to the tire radial direction inner side of the central portion,
The central portion is a linear pattern,
The outer portion is an arc-shaped pattern that is convex on one side in the tire circumferential direction,
The inner portion is an arc-shaped pattern that is convex on the other side in the tire circumferential direction,
The outer portion and the inner portion include a plurality of arc-shaped patterns with different curvature radii,
The pneumatic tire according to claim 1, wherein the decorative pattern includes a plurality of intersections where adjacent unit patterns intersect in the outer portion and the inner portion, and the central portion does not have the intersection.   2. The pneumatic tire according to claim 1, wherein in each of the unit patterns, a straight line connecting an inner end and an outer end in the tire radial direction is located on the tire radial line.   The pneumatic tire according to claim 1 or 2, wherein the linear pattern has an angle of 45 ° or less with respect to a tire radial direction.   The ratio (L1 / L) between the length L of the unit pattern in the tire radial direction and the length L1 of the central portion in the tire radial direction is in the range of 0.04 to 0.19. The pneumatic tire according to any one of the above. The outer portion and the inner portion include a first arc-shaped pattern having the largest radius of curvature R1, a second arc-shaped pattern having the smallest radius of curvature R2 , the first arc-shaped pattern, and the second arc-shaped pattern. A third arc-shaped pattern with a radius of curvature R3 between,
The ratio (R3 / R1) of the radius of curvature R3 of the third arc-shaped pattern and the radius of curvature R1 of the first arc-shaped pattern is in the range of 0.36 to 0.93,
The ratio (R2 / R3) between the radius of curvature R2 of the second arc-shaped pattern and the radius of curvature R3 of the third arc-shaped pattern is in the range of 0.31 to 0.81. Pneumatic tire described in 2. Both ends of the plurality of arc-shaped patterns having different curvature radii of the outer portion are all terminated at the same position of both ends in the radial direction of the outer portion,
  The pneumatic tire according to any one of claims 1 to 5, wherein both end portions of a plurality of arc-shaped patterns having different curvature radii of the inner side portion are terminated at the same position of both end portions in the radial direction of the inner side portion.

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