JP6547557B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire in which a decorative pattern including a plurality of ridge-like ridges is formed on the surface of a sidewall portion.

  Conventionally, as shown in FIG. 10 (a) and FIG. 10 (b), which is a cross section taken along the line A-A, a pneumatic tire a in which a decorative pattern c is formed on the sidewall portion b has been proposed (for example, Patent Document 1) below. The decorative pattern c includes a plurality of ridge-like ridges d extending in the tire radial direction and aligned in the tire circumferential direction, and narrow grooves e extending in the tire radial direction formed between the ridges d and d.

  Generally, the sidewall portion b is thin in rubber thickness, and unevenness called bulge or dent tends to be noticeable due to the joint of the carcass which is an internal structural material, residual air, and the like. In the conventional tire a, the decorative pattern c provided on the sidewall portion b makes the unevenness less noticeable.

Unexamined-Japanese-Patent No. 2004-17829

  However, in the conventional decorative pattern c, since each ridge d has a certain width and height, the difference in brightness is uniform equally at any position of the decorative pattern c, and the blinding effect makes the asperities inconspicuous. Was not able to demonstrate enough. Further, when the sidewall portion b is expanded by filling the tire a with air pressure, stress is concentrated on the surface portion of each ridge d, and there is a possibility that a crack may be generated therefrom.

  The present invention has been made in view of the above problems, and has as its main object to provide a pneumatic tire capable of improving the blinding effect for making the unevenness of the side wall portion inconspicuous and suppressing cracks originating from the ridge. There is.

  Among the present inventions, the invention according to claim 1 is a pneumatic tire having a sidewall portion, wherein a plurality of ridges extending in the tire radial direction and aligned in the tire circumferential direction are provided on the surface of the sidewall portion. A decorative pattern is formed including a ridge-like ridge and a narrow groove extending in the tire radial direction between the adjacent ridges, wherein the ridge has a ridge height which is the height from the groove bottom of the narrow groove; It has a ridge width which is a width in the tire circumferential direction, and the ridge height and the ridge width change in the tire radial direction.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the ridge includes at least one neck portion at which the ridge width is minimized.

  The invention according to claim 3 is characterized in that the ridge includes at least one constriction where the ridge width is the smallest, and the ridge height is the smallest in the respective constrictions. Pneumatic tire.

  The invention according to claim 4 is the air-containing according to claim 2 or 3, wherein the ridge includes a constriction portion in which the ridge width is minimum and a widening portion in which the ridge width gradually increases from the constriction portion. It is a tire.

  The invention according to claim 5 is the pneumatic tire according to any one of claims 2 to 4, wherein the ridge includes two or more of the narrow portions.

  The invention according to claim 6 is the pneumatic tire according to any one of claims 2 to 4, wherein the ridge is provided with the narrow portion at a central portion in the radial direction of the tire.

  The invention according to claim 7 is that, in a front view of the side wall portion, each of the ridges has a line-symmetrical shape with respect to a tire radial direction line passing through the tire rotation axis. It is a pneumatic tire.

  The invention according to claim 8 is the pneumatic tire according to any one of claims 1 to 7, wherein the ridges are arranged at different formation pitches in the circumferential direction of the tire in a front view of the sidewall portion. It is.

  The pneumatic tire of the present invention includes a sidewall portion having a decorative pattern including a ridge whose ridge height and ridge width change in the radial direction of the tire. In such a decorative pattern, light is less likely to be reflected in the narrow groove between the ridges at a position where the ridge height or the ridge width is large, and the narrow groove is visually recognized to be dark. Conversely, at a position where the ridge height or the ridge width is small, more light is reflected in the narrow groove and the narrow groove is visually recognized bright. That is, in the present invention, the decorative pattern can include a portion where the difference between light and dark becomes large. Therefore, the decorative pattern can make the unevenness of the side wall part further blurred and inconspicuous due to the difference between light and dark, and improve the blinding effect.

  Further, according to the present invention, in each ridge, at the position where the ridge height or the ridge width is small, the rigidity of the ridges becomes small and it becomes easy to be deformed. For this reason, at the time of internal pressure filling, the stress acting on the ridge at this small portion of rigidity is relaxed. Therefore, the generation of cracks originating from the ridge can be suppressed.

  Furthermore, when the mark is formed along the decorative pattern using the difference in light and dark due to the decorative pattern, the difference in light and dark affects the vision, and the mark can be viewed in three dimensions, and the design of the mark Improve the quality.

It is a principal part enlarged front view of a pneumatic tire showing this embodiment. FIG. 2 is a tire meridional cross-sectional view of a sidewall portion of FIG. 1; It is an expansion perspective view of a decoration pattern. It is an expansion perspective view of other decoration patterns. It is an expansion perspective view of other decoration patterns. It is an expansion perspective view of other decoration patterns. It is an expansion perspective view of other decoration patterns. It is an expansion perspective view of other decoration patterns. It is an expansion perspective view of other decoration patterns. (A) is a partial front view of the conventional pneumatic tire, (b) is the AA sectional view.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
FIG. 1 shows a front view of a sidewall portion 2 of a pneumatic tire (hereinafter sometimes simply referred to as a “tire”) 1 of the present embodiment. As shown in FIG. 1, a decorative pattern 5 including a plurality of ridge-like ridges 3 and narrow grooves 4 formed between the ridges 3 is formed on the surface 2S of the sidewall portion 2.

  The decorative pattern 5 is a strip extending around the tire rotation axis in the tire circumferential direction. The decorative pattern 5 may be, for example, an annular shape continuously extending in the tire circumferential direction or an arc shape formed in a part of the tire circumferential direction.

  The ridges 3 extend in the tire radial direction and are aligned in the tire circumferential direction. Therefore, the narrow grooves 4 formed between the ridges 3 and 3 also extend in the tire radial direction.

  FIG. 2 is a meridional cross section including the tire rotation axis of the tire 1. The tire 1 of the present embodiment includes, for example, a carcass 11 extending from the tread portion 10 through the sidewall portion 2 to a bead core (not shown) of a bead portion (not shown) and a tire axial direction outer side of the carcass 11 and a sidewall portion And sidewall rubbers 2G arranged in two. The decorative pattern 5 is formed on the sidewall rubber 2G by, for example, vulcanization molding.

  As shown in FIG. 2, the decorative pattern 5 of the present embodiment extends in the tire radial direction between the outer rib 6 a extending in the tire circumferential direction and the inner rib 6 b. In the present embodiment, both ends of the ridge 3 and the narrow groove 4 in the tire radial direction are connected to the outer rib 6a and the inner rib 6b, respectively.

  The outer rib 6a and the inner rib 6b are raised outward in the tire axial direction, and are continuously formed in the tire circumferential direction, for example, on the surface 2S of the sidewall portion 2. The rib 6a and the rib 6b can reinforce both ridges 3 and both ends of each narrow groove 4 and can suppress the occurrence of cracks originating from these.

  A schematic perspective view of the decorative pattern 5 is shown in FIG. In FIG. 3, the tire circumferential direction and the tire radial direction are respectively illustrated linearly. As shown in FIG. 3, in the ridge 3, the ridge height Rh and the ridge width Rw change in the tire radial direction.

  According to such a decorative pattern 5, at the position where the ridge height Rh or the ridge width Rw is small, more light reaches and is reflected on the groove bottom 4 a or the like of the narrow groove 4 and the narrow groove 4 is visually recognized bright Ru. Conversely, at a position where the ridge height Rh or the ridge width Rw is large, light does not easily reach the groove bottom 4a of the narrow groove 4 or the like, and the narrow groove 4 is visually recognized dark. For this reason, the decorative pattern 5 can include a portion where the difference between light and dark is large. Therefore, the decorative pattern 5 of the present embodiment can further improve the blinding effect of blurring the unevenness of the side wall portion 2 due to the difference between light and dark and making the unevenness not noticeable.

  Further, according to the decorative pattern 5 of the present embodiment, by using the difference between light and dark, for example, a mark can be formed along the decorative pattern 5, which is desirable also from the viewpoint of improving the design of the mark. Furthermore, according to the decorative pattern 5 of the present embodiment, at the position where the ridge height Rh or the ridge width Rw is small, the rigidity of the ridge 3 becomes small, and the ridge 3 is easily deformed. Therefore, for example, when the tire 1 is filled with air pressure, even if stress is applied to the ridge 3 as the sidewall rubber 2G is deformed, the stress is relieved at a portion where the rigidity of the ridge 3 is relatively small. . As a result, the occurrence of cracks originating from the ridge 3 can be suppressed.

  As shown in FIG. 3, the ridge 3 preferably includes, for example, at least one constriction portion 7, and the constriction portion 7 is a portion where the ridge width Rw is minimum. In the ridge 3 of the present embodiment, the ridge width Rw and the ridge height Rh both become minimum at the constriction portion 7. Such ridges 3 receive a lot of light from the groove bottom 4a of the narrow groove 4 adjacent to the constricted portion 7 and are reflected to make the narrow groove 4 brightly visible locally. Further, since the ridge width Rw and the ridge height Rh are minimized, the rigidity is relatively small and the neck portion 7 of the ridge 3 is easily deformed. Therefore, the stress acting on the ridge 3 is relieved at the constriction 7 and the generation of the crack is more effectively suppressed.

  The ridge 3 includes, for example, a widening portion 8 in which the ridge width Rw gradually increases in the tire radial direction from the constriction portion 7. In the ridge 3 of the present embodiment, for example, the ridge width Rw and the ridge height Rh gradually increase in the widening portion 8. Each widening portion 8 extends continuously from the constricted portion 7 to the outer rib 6a or the inner rib 6b, respectively. Such a ridge 3 can disperse the stress acting on the ridge 3 in the tire radial direction by the widening portion 8. Therefore, the stress acting on the ridge 3 can be further alleviated, such as during the internal pressure filling of the tire 1.

  It is desirable that the ridge 3 be provided, for example, with a constriction 7 at the central portion 3A of the length in the radial direction of the tire. The ridge 3 of the present embodiment is configured to include one constricted portion 7 provided at the central portion 3A of the length in the tire radial direction. The central portion 3A has an area of 15% from the center of the ridge length L inside and outside. Such a ridge 3 includes a constriction 7 at which the ridge width Rw and the ridge height Rh are minimized, and a pair of widenings 8 and 8 extending at the same length on both sides of the constriction 7. There is. Therefore, the stress acting on the ridge 3 is effectively dispersed by the pair of widening portions 8 and is surely relieved by the constriction portion 7.

  The ridge height Rh is the height from the deepest groove bottom 4 a of the narrow groove 4. The ridge height Rh is preferably 0.2 to 2 mm. When the ridge height Rh is smaller than 0.2 mm, the difference with the groove bottom 4a is small, and there is a possibility that the blinding effect by the ridge 3 can not be sufficiently obtained. Conversely, if the ridge height Rh is larger than 2 mm, the ridge 3 is likely to be cracked. From such a viewpoint, the ridge height Rh is more preferably 0.4 to 0.8 mm.

  The ridge width Rw is the width of the ridge 3 in the tire circumferential direction. The ridge width Rw is preferably 0.2 to 2.5 mm. If the ridge width Rw is smaller than 0.2 mm, there is a possibility that the blinding effect of the ridge 3 can not be sufficiently obtained. Conversely, when the ridge width Rw is larger than 2.5 mm, the ridge 3 tends to be cracked. From such a point of view, the ridge width Rw is more preferably 0.6 to 1.2 mm.

  The ridge 3 is, for example, line symmetrical with respect to a tire radial direction line CL (shown as a center line in the present embodiment) passing through the tire rotation axis in a front view of the sidewall portion 2 (viewpoint from one end side of the tire rotation axis). It is desirable to have a shape. Such a ridge 3 can make the decorative pattern 5 include a difference in light and dark even when the sidewall portion 2 is viewed from any one side of the tire radial direction line CL in the tire circumferential direction.

  The ridge 3 of the present embodiment is formed, for example, in a triangular shape in the cross section of the decorative pattern 5 (the cross section perpendicular to the longitudinal direction of the ridge 3). The rigidity of such a ridge 3 decreases toward the tire outer side, and surface distortion and the like concentrated on the tire outer side of the ridge 3 can be more effectively alleviated.

  In the decorative pattern 5 of the present embodiment, the configuration of the ridges 3 adjacent to each other in the tire circumferential direction is the same, and the formation pitch P of the adjacent ridges 3 is constant. In such a decorative pattern 5, the ridges 3 are regularly aligned in the tire circumferential direction. Therefore, in the decorative pattern 5, application of a large stress to the specific ridge 3 is suppressed.

  The formation pitch P of the ridges 3 is preferably 0.5 to 5.0 mm. When the formation pitch P of the ridges 3 is smaller than 0.5 mm, the ridges 3 are small, and there is a possibility that the blinding effect by the ridges 3 can not be sufficiently obtained. Conversely, when the formation pitch P is larger than 5.0 mm, the groove width Rw of the ridge 3 or the width of the groove bottom 4 a of the narrow groove 4 becomes large, and the ridge 3 tends to be cracked. From such a point of view, the ridge width Rw is more preferably 0.6 to 3.0 mm.

  In addition, it is desirable that the decorative pattern 5 include 100 to 1800 ridges 3 in one sidewall portion 2. When the number of ridges 3 is less than 100, the forming pitch P of the ridges 3 in the tire circumferential direction and the ridge width Rw of the ridges 3 tend to be large. For this reason, the rigidity of each ridge 3 is increased, and a crack is easily generated. On the contrary, when the number of ridges 3 is more than 1,800, each ridge 3 tends to be small, and it may take much time to process the decorative pattern 5. From such a point of view, it is preferable that the decorative pattern 5 more preferably include 600 to 1500 ridges 3 in the tire circumferential direction.

  FIGS. 4 to 9 show enlarged perspective views of the decorative pattern 5 on which a ridge of another embodiment is formed. Hereinafter, the same reference numerals are given to the same components as the present embodiment, and the detailed description thereof will be omitted.

  In the embodiment of FIG. 4, the ridge 3 includes a plurality of (two in this embodiment) neck portions 7a and 7b in the tire radial direction. In addition, the ridge 3 includes four widenings 8 extending at the same length on both sides of each of the narrowings 7a, 7b. For this reason, the stress acting on the ridge 3 is effectively dispersed by the widening portions 8 and is surely relieved by the narrow portions 7a and 7b.

  In the embodiment of FIG. 5, the ridge 3 has, for example, a length L3 with a waist 7 at which the ridge height Rh and the ridge width Rw become minimum. It is desirable that the constricted portion 7 be provided including the central portion 3A in the tire radial direction. Such a ridge 3 can make the groove bottom 4a of the narrow groove 4 to which light is easily reflected be more widely visible over the length L3. Therefore, when forming a mark along the decorative pattern 5, the length L3 of the concavity 7 is set in advance according to the shape of the mark, so that the light and dark in the predetermined range of the decorative pattern 5 can be obtained. The difference can be made constant, and the design of the mark can be improved.

  It is desirable that the length L3 of the constricted portion 7 be 10 mm or less. When the length L3 of the constricted portion 7 is larger than 10 mm, the rigidity of the constricted portion 7 is increased, and a crack may occur in the constricted portion 7.

  In the embodiment of FIG. 6, the decorative pattern 5 comprises ridges 3 of different configuration. The ridge 3 includes, for example, a first ridge 3a having a large ridge width Rw and a ridge height Rh, and a second ridge 3b having a ridge width Rw and a ridge height Rh smaller than the first ridge 3a. For example, the formation pitches P1 and P2 are different between the first ridge 3a and the second ridge 3b. In such a decorative pattern 5, the width of the groove bottom 4a of the narrow groove 4 is also different. For this reason, the difference in brightness and darkness can be randomly changed in the tire circumferential direction of the decorative pattern 5. Therefore, the blinding effect which makes the unevenness | corrugation of the sidewall part 2 inconspicuous can be improved more.

  In the embodiment of FIGS. 7 and 8, the cross section of the ridge 3 is formed in, for example, a trapezoidal shape or an arc shape. Further, the ridge 3 may be formed, for example, in a rectangular shape in the cross section (not shown). These ridges 3 have, for example, an upper surface formed of a flat surface or a curved surface. Therefore, light can be reflected by the upper surface of each ridge 3 together with the groove bottom 4 a of the narrow groove 4, and the design of the mark by the decorative pattern 5 can be improved.

  The decorative pattern 5 may be configured to include ridges 3 of different shapes in the cross section of the decorative pattern 5, such as triangular, trapezoidal, circular and rectangular shapes, for example. It can be improved more.

  In the embodiment of FIG. 9, the cross section of the ridge 3 is formed, for example, in a sawtooth shape. The sawtooth-shaped ridge 3 is not axisymmetric with respect to the tire radial line CL, and, for example, when the sidewall portion 2 is viewed from one side of the tire radial direction of the tire radial line CL, its upper surface Is invisible. Therefore, the appearance of the decorative pattern 5 can be differentiated between the case where the side wall part 2 is viewed from the one side and the case where the side wall part 2 is viewed from the other side contrary to the case where it is viewed from the other side. be able to.

  As mentioned above, although this embodiment was explained in full detail, the present invention is not limited to this embodiment, and can be changed into various modes and can be carried out.

  In order to confirm the effect of the present invention, a test pneumatic tire (size: 195 / 65R15) having a decorative pattern formed on the surface of the side wall part was made on the basis of each specification shown in Table 1, and blinding performance, It was tested for crack resistance performance and processability.

In addition, for comparison, a comparative tire having a decorative pattern with no change in ridge height and ridge width and no constricted portion was produced. The comparative tires were also tested in the same manner as the test tires.
Each evaluation method is as follows.

<Blindfold performance>
With respect to the sidewall portion of each test tire, irregularities such as bulges and dents were confirmed with the naked eye, and a sensory evaluation of the irregularities by visual observation was shown by a five-point method. In the evaluation, as the score is larger, unevenness can not be confirmed and the evaluation is superior.

<Crack resistance performance>
Each test tire was rim-set to the test rim, filled with an air pressure of 175 kPa, and loaded with a load of 6.17 kN, and drum traveling of 30,000 km was performed. Thereafter, with respect to the decorative pattern of each test tire, a crack originating from the ridge was visually confirmed, and a sensory evaluation of each ridge by visual observation was shown by a five-point method. In the evaluation, the number of cracks is five, the number of significant cracks is one, and the larger the number, the better.

<Processability>
The processability was measured by measuring the time required for processing each decorative pattern, and was shown by the 5-point method based on the measured time. In the evaluation, as the score is larger, the time required for processing is shorter and superior.
The results of the test are shown in Table 1.

  As a result of the test, the tire according to the example in which the ridge height and the ridge width change in the tire radial direction is superior in the blinding effect for making the unevenness of the sidewall portion inconspicuous, and suppresses the crack originating from the ridge. It was confirmed that it was possible.

1 Pneumatic tire 2 Side wall portion 2S surface 3 ridge 4 fine groove 5 decorative pattern 7 neck portion 8 widening portion

Claims (6)

A pneumatic tire having a sidewall portion,
A decorative pattern including on the surface of the sidewall portion, a plurality of ridge-shaped ridges extending in the tire radial direction and arranged in the tire circumferential direction, and narrow grooves extending in the tire radial direction formed between the adjacent ridges. Is formed,
The ridge has a ridge height which is a height from the groove bottom of the narrow groove and a ridge width which is a width in a tire circumferential direction,
The ridge height and the ridge width change in the tire radial direction ,
The pneumatic tire according to claim 1 , wherein the ridge includes at least one constricted portion in which the ridge width is minimized, and the ridge height is minimized in each of the narrowed portions . A pneumatic tire having a sidewall portion,
A decorative pattern including on the surface of the sidewall portion, a plurality of ridge-shaped ridges extending in the tire radial direction and arranged in the tire circumferential direction, and narrow grooves extending in the tire radial direction formed between the adjacent ridges. Is formed,
The ridge has a ridge height which is a height from the groove bottom of the narrow groove and a ridge width which is a width in a tire circumferential direction,
The ridge height and the ridge width change in the tire radial direction,
The pneumatic tire characterized in that the ridge includes two or more constricted portions where the ridge width is minimum. A pneumatic tire having a sidewall portion,
A decorative pattern including on the surface of the sidewall portion, a plurality of ridge-shaped ridges extending in the tire radial direction and arranged in the tire circumferential direction, and narrow grooves extending in the tire radial direction formed between the adjacent ridges. Is formed,
The ridge has a ridge height which is a height from the groove bottom of the narrow groove and a ridge width which is a width in a tire circumferential direction,
The ridge height and the ridge width change in the tire radial direction,
The pneumatic tire according to the present invention is characterized in that the ridge is provided with a narrow portion at which the width of the ridge is minimized at a central portion of a length in a radial direction of the tire. The ridge is a pneumatic tire according the previous SL constricted portion to any one of claims 1 to 3 ridge width contains a widened portion for increasing. The pneumatic tire according to any one of claims 1 to 4 , wherein in a front view of the sidewall portion, each of the ridges has a line-symmetrical shape with respect to a tire radial direction line passing through a tire rotation axis. The pneumatic tire according to any one of claims 1 to 5 , wherein the ridges are arranged at different formation pitches in the circumferential direction of the tire in a front view of the sidewall portion.