JP7650757B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

A pneumatic tire is known that has a pattern on the sidewall surface formed by lining up multiple ridges that extend along the tire surface.

Many of the conventional patterns on the surface of the sidewall are made up of numerous linear ridges arranged at equal intervals. As disclosed in Patent Document 1, patterns with curved ridges arranged at equal intervals are also known. Either pattern enhances the design of the sidewall.

JP 2014-180947 A

Although various patterns have been proposed to date, there is a demand for groundbreaking patterns that will produce unprecedented visual effects.

Therefore, the objective of the present invention is to provide a pneumatic tire that creates a visual effect.

The pneumatic tire of this embodiment is a pneumatic tire with a pattern on the surface of the sidewall, the pattern having a plurality of annular shapes that are longer in the tire circumferential direction than in the tire radial direction, the plurality of annular shapes are different in size but have a common center, and larger annular shapes are arranged at intervals outside smaller annular shapes so that the intervals in the tire circumferential direction are greater than the intervals in the tire radial direction.

By providing the above-mentioned features, the present invention can reduce bleeding and create a visual effect with a sense of depth.

Axial half cross-section of a pneumatic tire FIG. 2 is a view of the pneumatic tire of FIG. 1 from the tire axial direction. Enlargement of the pattern. Cross-sectional view of a convex strip forming a ring shape Cross-sectional view of a convex strip forming a ring shape Cross-sectional view of a convex strip forming a ring shape Cross-sectional view of a convex strip forming a ring shape Cross-sectional view of a convex strip forming a ring shape Cross-sectional view of a convex strip forming a ring shape FIG. 1 is a view of a decorative area of a modified pneumatic tire from the tire axial direction.

One embodiment of the present invention will be described below with reference to the drawings.

The pneumatic tire 1 of the embodiment has a structure similar to that of a typical radial tire, except for the sidewall structure. Figure 1 shows the cross-sectional structure of the pneumatic tire 1 of the embodiment. Note that Figure 1 shows only half of the tire in the axial direction, and the actual pneumatic tire 1 is nearly symmetrical with respect to the center line C.

In the pneumatic tire 1, beads 9 are provided on both sides of the tire in the axial direction. The beads 9 consist of a bead core made of a steel wire wound in a circle and a rubber bead filler provided on the radial outside of the bead core.

One or two carcass plies 2 are stretched across the beads 9 on both sides in the axial direction of the tire. The carcass ply 2 is a sheet-like member in which numerous ply cords arranged in a direction perpendicular to the tire circumferential direction are covered with rubber. The carcass ply 2 forms the skeleton shape of the pneumatic tire 1 between the beads 9 on both sides in the axial direction of the tire, and wraps the beads 9 by folding back and rolling up around the beads 9 from the inside to the outside in the axial direction of the tire. In addition, a rubber chafer 3 is provided at the axially outer location of the folded back portion 2a of the carcass ply 2.

In addition, one or more belts 4 are provided on the radially outer side of the carcass ply 2, and a belt reinforcing layer 5 is provided on the radially outer side of the belt 4. The belt 4 is a member made of many steel cords covered with rubber. The belt reinforcing layer 5 is a member made of many organic fiber cords covered with rubber. Tread rubber 6 is provided on the radially outer side of the belt reinforcing layer 5. The tread rubber 6 has many grooves to form a tread pattern.

In addition, sidewall rubber 7 is provided on both sides of the carcass ply 2 in the tire axial direction. The tread rubber 6 and the sidewall rubber 7 overlap at the buttresses, but either the tread rubber 6 or the sidewall rubber 7 may overlap on the tire surface side. The radially inner portion of the sidewall rubber 7 extends close to the bead 9 and covers part of the rubber chafer 3. In this embodiment, the sidewall 10 refers to not only the portion of the sidewall rubber 7 that appears on the tire surface, but also the entire area that can be seen when the pneumatic tire 1 is viewed from the tire axial direction.

A sheet-like inner liner 8 made of rubber with low air permeability is attached to the inside of the carcass ply 2. In addition to these components, other components such as underbelt pads and chafers are provided according to the functional needs of the tire.

As shown in Figures 1 and 2, a decorative area 11 and a band-shaped area 40 are provided on at least one of the sidewalls 10 on both sides in the tire axial direction.

The decorative area 11 is an annular area centered on the tire rotation axis. The decorative area 11 is an area of a constant width sandwiched between a small-diameter circular inner diameter side line 12 and a large-diameter circular outer diameter side line 13. The inner diameter side line 12 and the outer diameter side line 13 may be lines formed by concavities, convexities, or steps on the tire surface, or may be imaginary lines that do not actually exist. The width HA of the decorative area 11 in the tire radial direction RD is 5% to 60% (preferably 10% to 35%) of the tire cross-sectional height H (the length in the tire radial direction RD from the inner diameter end of the bead core to the outer diameter surface of the pneumatic tire 1).

The location of the decorative area 11 in the tire radial direction RD is a location that includes the position of the maximum width of the pneumatic tire 1. Here, the position of the maximum width of the pneumatic tire 1 refers to the position where the length in the tire axial direction from the surface of one sidewall 10 in the tire axial direction to the surface of the other sidewall 10 in the tire axial direction is the longest.

The decorative area 11 may be provided on the sidewall 10 so as to include a location where a step is likely to appear on the surface of the sidewall 10. The location where a step is likely to appear on the surface of the sidewall 10 is typically the location of the end of a tire component, such as a location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface or a location that overlaps with the end of the folded-up portion 2a of the carcass ply 2 in the tire width direction.

As shown in FIG. 2, two opposing locations of the annular decorative area 11 are provided with mark areas 11a in which a mark 16 is formed. Also, two opposing locations of the annular decorative area 11 are provided with pattern areas 11b in which a pattern 30 is formed, sandwiched between the two mark areas 11a.

In order to ensure sufficient spacing between adjacent marking regions 11a and pattern regions 11b, the minimum value of the distance LB between the end of marking region 11a and the end of pattern region 11b (the length in the tire circumferential direction CD from the mark 16 provided in marking region 11a to the end of the pattern 30 provided in pattern region 11b) is set to 3 mm. Also, in order to ensure a sufficient area for the pattern 30 provided in the decorative region 11, the maximum value of the distance LB between marking region 11a and pattern region 11b is set to 60% of the length LA in the tire circumferential direction CD of marking region 11a (the distance between the marks 16 provided at both ends of marking region 11a in the tire circumferential direction).

In the marking area 11a, one or more marks 16 are formed in a line in the tire circumferential direction CD. The marks 16 are made up of letters, numbers, symbols, figures, etc., and indicate various information such as the tire manufacturer, brand, variety, and size. These marks 16 that make up the marking area 11a are formed with a border of concave or convex lines.

In the pattern region 11b, a plurality of patterns 30 are formed in a line in the tire circumferential direction CD. As shown in Figures 2 and 3, the pattern 30 is formed by combining a plurality of annular figures 31 of different sizes. Preferably, the pattern 30 is formed by combining five or more annular figures 31.

Each of the multiple annular figures 31 that make up the pattern 30 is an annular figure that is longer in the tire circumferential direction CD than in the tire radial direction RD. In this embodiment, the multiple annular figures 31 are approximately elliptical.

For the multiple annular figures 31, the ratio of the length in the tire radial direction RD to the length in the tire circumferential direction CD is preferably 0.5 or more and 0.8 or less. In addition, the length in the tire radial direction RD of the largest annular figure 31 among the multiple annular figures 31 is preferably 50% or more and 95% or less of the width HA in the tire radial direction RD of the decorative area 11.

The multiple annular shapes 31 that make up the pattern 30 have a common center P, and are arranged around the smallest annular shape 31, with the multiple annular shapes 31 spaced apart from each other and surrounding each other without intersecting with each other.

Here, the center P of the annular figure 31 coincides with the center of gravity of the surface of the shape drawn by the annular figure 31. However, if the shape drawn by the annular figure 31 is a shape whose center is mathematically defined, the center P of the annular figure 31 is determined according to that definition.

When comparing the spacing Kr in the tire radial direction RD and the spacing Kc in the tire circumferential direction CD between adjacent annular figures 31, the spacing Kc in the tire circumferential direction CR is larger than the spacing Kr in the tire radial direction RD.

In addition, when comparing the spacing Kro on the outer side of the center P in the tire radial direction RD and the spacing Kri on the inner side of the tire radial direction RD for the multiple annular figures 31 adjacent to each other, the spacing Kro and the spacing Kri may be equal or different. If the two spacings are different, it is preferable that the spacing Kro on the outer side of the tire radial direction RD is larger than the spacing Kri on the inner side of the tire radial direction RD.

Here, the distance Kc between adjacent annular figures 31 in the tire circumferential direction CD is the distance from the center P on the annular figure 31 to the position farthest in the tire circumferential direction CD, and if the annular figure 31 is elliptical, it is the distance between the points on the major axis. Also, the distance Kr between adjacent annular figures 31 in the tire radial direction RD is the distance from the center P on the annular figure 31 to the position farthest in the tire radial direction RD, and if the annular figure 31 is elliptical, it is the distance between the points on the minor axis.

The distance Kc between adjacent annular figures 31 in the tire circumferential direction CD is preferably 0.2 mm or more and 2.4 mm or less. Also, the distance Kr between adjacent annular figures 31 in the tire radial direction RD is preferably 0.5 to 0.8 times the distance Kc in the tire circumferential direction CD.

The intervals Kc between the multiple annular figures 31 in the tire circumferential direction CD may be gradually increased from the inside to the outside as shown in FIG. 3, or may be equal intervals. The intervals Kr between the multiple annular figures 31 in the tire radial direction RD may be gradually increased from the inside to the outside as shown in FIG. 3, or may be equal intervals.

The centers P of the multiple patterns 30 provided in the pattern region 11b are located on a single reference line 21. Here, the reference line 21 is a line that extends in the tire circumferential direction through a specific position in the tire radial direction in the decorative region 11. This reference line 21 is not actually drawn in the decorative region 11, but is a virtual line. It is preferable that the tire radial position of the reference line 21 is the tire radial center position in the decorative region 11. In addition, it is preferable that the reference line 21 is a line that draws a circle centered on the tire rotation axis and has a radius of 45% to 65% of the tire cross-sectional height H.

Each of the multiple ring-shaped figures 31 is formed by connecting a groove recessed into the surface of the sidewall or a ridge protruding from the surface of the sidewall in a ring shape. When the ring-shaped figure 31 is formed from the ridge 20, the cross-sectional shape in the direction perpendicular to the longitudinal direction of the ridge 20 can be a semicircle as shown in FIG. 4, a shape consisting of a semicircle and a straight line below it as shown in FIG. 5, a triangle as shown in FIG. 6, a triangle with rounded apexes as shown in FIG. 7, a trapezoid as shown in FIG. 8, or a rectangle as shown in FIG. 9. Here, the triangle with rounded apexes as shown in FIG. 7 is a type of triangle. Although not shown, there may also be shapes that are slightly modified from these cross-sectional shapes, such as a sawtooth shape that is modified by tilting the triangle in FIG. 6. The line drawn as the ring-shaped figure 31 in FIG. 2 and FIG. 3 is the center line of the ridge 20 in the width direction (the line at the position indicated by T in FIG. 4 to FIG. 9).

In any of the cross-sectional shapes of the convex ribs 20 in Figures 4 to 9, the height H1 of the convex ribs 20 is 0.1 mm or more and 0.8 mm or less (preferably 0.1 mm or more and 0.4 mm or less). In any of the cross-sectional shapes of the convex ribs 20, the width W1 of the convex ribs 20 is 0.1 mm or more and 1.0 mm or less. The convex ribs 20 can be formed by a mold used during vulcanization molding. The convex ribs 20 can be formed by various processes such as mechanical processing and laser processing. Small convex ribs 20 with a height H1 of about 0.1 mm to 0.2 mm and a width W1 of about 0.1 mm to 0.2 mm can be formed by a mold in which fine irregularities are formed by laser processing.

If the radius of the semicircle in Figures 4 and 5 is R, then the length H2 of the straight line of the convex rib 20 having a cross-sectional shape as shown in Figure 5, which is composed of a semicircle and a straight line, is (height H1 of the convex rib 20) - (radius R of the semicircle). In the convex rib 20 having a trapezoidal cross section as shown in Figure 8, the length W2 of the upper base is 20% to 50% of the length of the lower base (i.e., width W1 of the convex rib 20).

In this embodiment, as shown in FIG. 2, multiple patterns 30 are provided in the decorative area 11 at intervals in the tire circumferential direction CD. It is preferable that the multiple patterns 30 are arranged so that other patterns 30 are located at positions opposite each other across the tire rotation axis.

The band-shaped region 40 is an annular region provided adjacent to the outer periphery of the decorative region 11. The band-shaped region 40 is provided with a plurality of ridges 41 protruding from the outer surface of the sidewall 10. In one embodiment, the plurality of ridges 41 are equally spaced apart in the tire circumferential direction CD at intervals of 0.3 to 1.0 mm. The band-shaped region 40 may be provided in a portion of the tire circumferential direction CD, but in this example, it is provided over the entire circumference of the tire circumferential direction CD. Therefore, the band-shaped region 40 is formed in a ring shape adjacent to the outside of the decorative region 11 and surrounding it over the entire circumference. The dimension HC (see FIG. 1) of the band-shaped region 40 in the tire radial direction RD is preferably 5 mm to 12 mm.

By providing such a band-like region 40, it is possible to suppress unevenness and bareness at the interface between the tread rubber 6 and the sidewall 10. In addition, the black band-like region 40 is formed by the light attenuation effect caused by providing the protruding stripes 41, making the decorative region 11 stand out.

Similar to the decorative region 11, such a band-like region 40 may be provided on the sidewall 10 so as to include locations where steps are likely to appear on the surface of the sidewall 10, such as locations where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, locations where the end of the folded-back portion 2a of the carcass ply 2 overlaps in the tire width direction, locations where the end of the belt 4 overlaps in the tire width direction, and other tire component ends. A parting line 42, which is a dividing line between the tread mold and the sidewall mold in the tire mold, may be formed at the boundary portion on the outer side of the tire radial direction of the band-like region 40.

In the pneumatic tire 1 of this embodiment, the sidewall 10 is provided with a pattern 30 in which a number of annular figures 31 are arranged with a common center and spaced apart in the tire circumferential direction and tire radial direction so that the spacing in the tire circumferential direction is greater than the spacing in the tire radial direction. This creates a visual effect with a sense of depth while suppressing bleeding compared to when adjacent annular figures 31 are spaced apart equally in the tire radial direction RD and tire circumferential direction CD.

(Example of change)
The above-described embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

For example, the shape of the multiple annular figures 31 is not limited to the approximately elliptical shape of the above embodiment.
Any ring-shaped figure may be used as long as it is longer in the tire circumferential direction CD than in the tire radial direction RD when viewed from a direction perpendicular to the surface of the sidewall 10. Among such ring-shaped figures, a preferred shape is a shape called an oval. An oval is a closed ring-shaped shape that is mainly composed of curves (for example, more than half of the total length of the lines forming the outline of the ring-shaped figure 31 are curves). In addition to the elliptical shape of the above embodiment, ovals also include ovals, perfect circles, egg shapes, etc. In addition, ovals also include closed curves formed by the intersection of the surface of a cone with a plane that completely crosses the cone.

In addition, when multiple annular figures 31 are provided in one pattern 30, some of the larger annular figures 31b may not fit within the decorative area 11 as shown in FIG. 14 and may be cut off. In such a case, it is preferable to provide multiple annular figures 31 in one pattern 30 so that five or more annular figures 31 fit within the decorative area 11.

In addition, in the above embodiment, two pattern regions 11b are provided for one sidewall 10, but one or three or more pattern regions 11b may be provided for one sidewall 10.

In addition, in the above embodiment, four patterns 30 are provided in one pattern area 11b, but any number of patterns 30 may be provided in one pattern area 11b.

The above dimensions in this specification are for a pneumatic tire mounted on a standard rim and inflated to the standard internal pressure under normal load. A standard rim is a "standard rim" in the JATMA standard, and a "Measuring Rim" in the TRA and ETRTO standards. A standard internal pressure is the "maximum air pressure" in the JATMA standard, the "maximum value" listed in the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, or the "INFLATION PRESSURE" in the ETRTO standard. However, for passenger car tires, the standard is usually 180 kPa, but for tires labeled "Extra Load" or "Reinforced," the standard is 220 kPa.

The various numerical ranges described in the specification can be arbitrarily combined with their upper and lower limits, and all such combinations are considered to be preferred numerical ranges described in this specification. In addition, a numerical range described as "X to Y" means greater than or equal to X and less than or equal to Y.

1...pneumatic tire, 4...belt, 6...tread rubber, 7...sidewall rubber, 9...bead, 10...sidewall, 11...decorative area, 11a...marking area, 11b...pattern area, 12...inner diameter side line, 13...outer diameter side line, 16...marking, reference line...21, 30...pattern, 31...annular figure, P...center

Claims (6)

In a pneumatic tire having a pattern on the surface of the sidewall,
The pattern has a plurality of annular figures that are longer in the tire circumferential direction than in the tire radial direction,
The pneumatic tire has a plurality of annular figures that are different in size, have a common center, and are arranged with a gap between smaller annular figures on the outside so that the gap between the larger annular figures is larger in the circumferential direction of the tire than in the radial direction of the tire. The pneumatic tire according to claim 1, wherein the annular shape is an egg-shaped shape. The pneumatic tire according to claim 1 or 2, wherein the ratio of the length of the annular shape in the tire radial direction to the length in the tire circumferential direction is 0.5 or more and 0.8 or less. The plurality of annular figures are formed of grooves recessed into a surface of the sidewall or ridges protruding from a surface of the sidewall,
The pneumatic tire according to any one of claims 1 to 3, wherein the cross-sectional shape of the plurality of annular figures is a triangle, a trapezoid, or a semicircle. A pneumatic tire according to any one of claims 1 to 4, wherein the spacing between adjacent annular figures on the outer side in the tire radial direction is greater than the spacing between adjacent annular figures on the inner side in the tire radial direction. The pneumatic tire according to any one of claims 1 to 5, wherein a region is provided in the sidewall, radially outward of the decorative region in which the annular figure is provided, in which a plurality of ridges extending in the tire radial direction are arranged at equal intervals in the tire circumferential direction, the region having a dimension in the tire radial direction of 5 mm or more and 12 mm or less.

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