JP7359622B2 - pneumatic tires - Google Patents

Description

The present invention relates to pneumatic tires.

Unnecessary unevenness may occur on the surface of the sidewall portion of a pneumatic tire. For example, the shape of the end of a carcass ply inside a pneumatic tire may appear as irregularities on the surface of the sidewall portion. Such irregularities deteriorate the appearance quality of the pneumatic tire.

On the other hand, as described in Patent Document 1 and Patent Document 2, it is known to provide a large number of ridges, which are protrusions, on the sidewall portion of a pneumatic tire. With such a large number of ridges, unnecessary unevenness on the surface of the sidewall portion becomes less noticeable, improving the appearance quality of the pneumatic tire.

Patent No. 4947225 Patent No. 5310805

By the way, in the pneumatic tires of Patent Document 1 and Patent Document 2, each ridge is linear, and the extending direction of the ridge is different depending on the location. The ends of the linear ridges are not connected to each other.

In such a pneumatic tire, when the pneumatic tire rolls and the sidewall portion repeatedly bends, cracks may occur from the ends of the ridges and the like. One of the problems when such cracks occur is that the appearance of the pneumatic tire deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire with better appearance quality.

The pneumatic tire of the embodiment is provided with serrations extending in the circumferential direction of the tire on at least one of the sidewall portions on both sides in the width direction of the tire, and a plurality of ridges, which are convex stripes, arranged on the serrations in the circumferential direction of the tire. In the tire, each of the ridges extends in the tire radial direction while having a bent portion, and a plurality of virtual lines connecting the closest bent portions of the adjacent ridges are formed, and each of the virtual lines is a curved line. , the adjacent virtual lines have different shapes, and the serrations are provided in a part of the decorative area sandwiched between the inner diameter side edge of the small diameter circle and the outer diameter side edge of the large diameter circle, The plurality of ridges extend from the inner edge to the outer edge, and each of the adjacent virtual lines extends from the inner edge to the outer edge. do.

According to the pneumatic tire of the embodiment, since the ridge extends in the tire radial direction while having a bent portion, deflection of the sidewall portion is suppressed and generation of cracks is suppressed. Furthermore, since the shapes of adjacent virtual lines are different, unnecessary irregularities on the surface of the sidewall portion become less noticeable. Therefore, the appearance quality of the pneumatic tire is improved.

A half cross-sectional view in the width direction of a pneumatic tire. A diagram of a pneumatic tire viewed from the axial direction. An enlarged view of the serrations in FIG. 2. A diagram in which virtual lines are added to the serrations in FIG. 3. 4 is a partially enlarged view of the vicinity of the boundary between range C and range D of serrations in FIG. 3. FIG. A cross-sectional view of the ridge (XX cross-sectional view in FIG. 5). A cross-sectional view of the ridge (XX cross-sectional view in FIG. 5). A cross-sectional view of the ridge (XX cross-sectional view in FIG. 5).

The pneumatic tire 1 of the embodiment has the same structure as a general radial tire except for the structure of the sidewall portion. FIG. 1 illustrates a rough cross-sectional structure of a pneumatic tire 1 according to an embodiment. Note that only half of the tire in the width direction is shown in FIG. 1, and the actual pneumatic tire 1 is substantially symmetrical with respect to the center line C.

In the pneumatic tire 1, bead portions 9 are provided on both sides in the tire width direction. The bead portion 9 includes a bead core made of a circularly wound steel wire and a rubber bead filler provided on the radially outer side of the bead core.

One or two carcass plies 2 are spanned over the bead portions 9 on both sides in the tire width direction. The carcass ply 2 is a sheet-like member in which a large number of ply cords arranged in a direction perpendicular to the tire circumferential direction are coated with rubber. The carcass ply 2 forms the skeleton shape of the pneumatic tire 1 between the bead portions 9 on both sides in the tire width direction, and is folded back and rolled up from the inside to the outside in the tire width direction around the bead portion 9. is wrapped around. Further, a rubber chafer 3 is provided at a location outside the folded portion 2a of the carcass ply 2 in the tire width direction.

Furthermore, one or more belts 4 are provided on the outside of the carcass ply 2 in the tire radial direction, and a belt reinforcing layer 5 is provided on the outside of the belt 4 in the tire radial direction. The belt 4 is a member made of a large number of steel cords covered with rubber. The belt reinforcing layer 5 is a member made of a large number of cords made of organic fibers covered with rubber. Tread rubber 6 is provided on the outside of the belt reinforcing layer 5 in the tire radial direction. The tread rubber 6 is provided with a large number of grooves to form a tread pattern.

Furthermore, sidewall rubber 7 is provided on both sides of the carcass ply 2 in the tire width direction. Although the tread rubber 6 and the sidewall rubber 7 overlap at the buttress portion, either the tread rubber 6 or the sidewall rubber 7 may overlap on the tire surface side. The inner portion of the sidewall rubber 7 in the tire radial direction extends close to the bead portion 9 and covers a portion of the rubber chafer 3. In this embodiment, not only the portion where the sidewall rubber 7 appears on the tire surface but also the entire visible range when the pneumatic tire 1 is viewed from the tire axial direction is defined as the sidewall portion 10.

Furthermore, 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 members, members such as an under-belt pad and a chafer are provided depending on the functional needs of the tire.

Next, the sidewall portion 10 will be explained.

As shown in FIGS. 1 and 2, an annular decorative region 11 centered around the tire rotation axis is provided on at least one of the sidewall portions 10 on both sides in the tire width direction. The decorative region 11 is a region of a constant width sandwiched between a small-diameter circular inner diameter side edge 12 and a large-diameter circular outer diameter side edge 13.

Although the position of the decorative region 11 in the tire radial direction is not limited, in FIG. 1, the decorative region 11 is provided in a shape that includes a location where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface. In this way, it is preferable that the decorative region 11 is provided in a form that includes a place where a step is likely to appear on the surface of the sidewall portion 10. The location where a step is likely to appear on the surface of the sidewall portion 10 is typically the location at the end of the tire component. In addition to the above-mentioned locations where the interface between the tread rubber 6 and the sidewall rubber 7 appears on the tire surface, examples of such typical locations include, for example, the rolled-up end 2b of the carcass ply 2 (the folded end of the carcass ply 2). 2a) in the tire width direction.

As shown in FIG. 2, serrations 14 having a constant width and extending in the tire circumferential direction are provided at two opposing locations in the annular decorative region 11. The serrations 14 are formed by a large number of ridges 20 extending in the tire radial direction and arranged at regular intervals in the tire circumferential direction. Here, the ridge 20 is a protruding ridge that protrudes from the tire surface and extends long along the tire surface. The cross-sectional shape of the ridge 20 in the direction orthogonal to the longitudinal direction includes a semicircle shown in FIG. 6, a triangle shown in FIG. 7, and a trapezoid shown in FIG. 8. Note that the line drawn as the ridge 20 in FIGS. 2 to 5 is the center line of the ridge 20 (the line indicated by P in FIGS. 6 to 8).

Each ridge 20 extends in the tire radial direction while being bent. Each ridge 20 is continuous as a single convex strip from the inner diameter side edge 12 to the outer diameter side edge 13, and is not interrupted by a bent portion or the like. In order to explain the details of the bending, at least ranges A, B, C, D, and E are set in the inner diameter side edge 12 in order in the tire circumferential direction, as shown in FIG.

Each ridge 20a starting from range A of the inner diameter side edge 12 has two bent parts, a first bent part 21a close to the inner diameter side edge 12 and a second bent part 22a close to the outer diameter side edge 13. have. Each ridge 20a includes a first line portion 23a extending from the inner diameter side edge 12 to the first bent portion 21a, a second line portion 24a extending from the first bent portion 21a to the second bent portion 22a, and a second line portion 24a extending from the first bent portion 21a to the second bent portion 22a. It has a third line portion 25a extending from the bent portion 22a to the outer diameter side edge 13.

Further, each ridge 20b starting from range B of the inner diameter side edge 12 has a first bent part 21b closest to the inner diameter side edge 12, and a second bent part 22b next closest to the inner diameter side edge 12. and a third bent portion 26b closest to the outer diameter side edge 13. Each ridge 20b includes a first line portion 23b extending from the inner diameter side edge 12 to the first bent portion 21b, a second line portion 24b extending from the first bent portion 21b to the second bent portion 22b, and a second line portion 24b extending from the first bent portion 21b to the second bent portion 22b. It has a third line part 25b extending from the bending part 22b to the third bending part 26b, and a fourth line part 27b extending from the third bending part 26b to the outer diameter side edge 13.

Moreover, each ridge 20c starting from the range C of the inner diameter side edge 12 has two bending parts, a first bending part 21c near the inner diameter side edge 12 and a second bending part 22c near the outer diameter side edge 13. It has a bent part. Each ridge 20c includes a first line portion 23c extending from the inner diameter side edge 12 to the first bent portion 21c, a second line portion 24c extending from the first bent portion 21c to the second bent portion 22c, and a second line portion 24c extending from the first bent portion 21c to the second bent portion 22c. It has a third line portion 25c extending from the bent portion 22c to the outer diameter side edge 13.

Moreover, each ridge 20d starting from the range D of the inner diameter side edge 12 has a first bent part 21d closest to the inner diameter side edge 12, and a second bent part 22d next closest to the inner diameter side edge 12. and a third bent portion 26d closest to the outer diameter side edge 13. Each ridge 20d includes a first line portion 23d extending from the inner diameter side edge 12 to the first bent portion 21d, a second line portion 24d extending from the first bent portion 21d to the second bent portion 22d, and a second line portion 24d extending from the first bent portion 21d to the second bent portion 22d. It has a third line part 25d extending from the bending part 22d to the third bending part 26d, and a fourth line part 27d extending from the third bending part 26d to the outer diameter side edge 13.

Each ridge 20e starting from the range E of the inner diameter side edge 12 has two bent parts, a first bent part 21e close to the inner diameter side edge 12 and a second bent part 22e close to the outer diameter side edge 13. have. Each ridge 20e includes a first line portion 23e extending from the inner diameter side edge 12 to the first bent portion 21e, a second line portion 24e extending from the first bent portion 21e to the second bent portion 22e, and a second line portion 24e extending from the first bent portion 21e to the second bent portion 22e. It has a third line portion 25e extending from the bent portion 22e to the outer diameter side edge 13.

Here, the first line portions 23a, 23d, and 23e starting from ranges A, D, and E have the same inclination angle θ1 (see FIG. 5) with respect to the tangential direction of the inner diameter side edge portion 12. Further, the first line portions 23b and 23c starting from ranges B and C have the same inclination angle θ2 (see FIG. 5) with respect to the tangential direction of the inner diameter side edge portion 12.

The ridges 20 that extend in the tire radial direction while being bent in this manner are lined up, but the position of the bent portion in the tire radial direction gradually moves in the tire radial direction as it moves to the adjacent ridge 20. By connecting the closest bent portions of adjacent ridges 20 one after another, a curved virtual line 30 (see FIG. 4) is formed when viewed from the tire axial direction.

For example, as shown in FIG. 4, by sequentially connecting the first bent portion 21a of the ridge 20a, the second bent portion 22b of the ridge 20b, the second bent portion 22c of the ridge 20c, and the third bent portion 26d of the ridge 20d. , one virtual line 30a is formed. Also, by sequentially connecting the first bent part 21b of the ridge 20b, the first bent part 21c of the ridge 20c, the second bent part 22d of the ridge 20d, and the second bent part 22e of the ridge 20e, one virtual line can be formed. 30b is formed. One virtual line 30 is formed by connecting the other bent portions one after another. Note that the virtual line 30 is just a virtual line, and is not actually a single concave or convex line drawn on the tire surface.

Each imaginary line 30 extends from the inner diameter side edge 12 side of the decoration area 11 toward the outer diameter side edge 13 side. A plurality of such virtual lines 30 are formed in one serration 14 to form a pattern. Here, for example, as can be seen from the comparison between the virtual line 30a and the virtual line 30b next to it, the two adjacent virtual lines 30 have different shapes and are not parallel. Therefore, even if one virtual line 30 is moved to the position of the adjacent virtual line 30, these virtual lines 30 do not overlap.

In the range of the ridge 20 in which the first line portion has the same inclination angle with respect to the tangential direction of the inner diameter side edge 12, for example, the range of the ridge 20b and the ridge 20c (that is, the range of the ridge 20 extending from the range B and the range C) When viewed in a limited manner, a virtual line 30 connecting the first bent portions 21b and 21c (part of the virtual line 30b described above) and a virtual line 30 connecting the second bent portions 22b and 22c (a portion of the virtual line 30a described above) ) is different in shape and is not parallel.

Although the size of the bending angle of each bending portion is not limited, it is preferably 90° or more. Note that the "size of the bending angle" herein refers to the angle on the inferior angle (the smaller angle among the angles that share two sides with the vertex). Moreover, it is preferable that the bending angles of all the bending parts on one common virtual line 30 are the same. For example, the bending angles of the first bending part 21a of the ridge 20a, the second bending part 22b of the ridge 20b, the second bending part 22c of the ridge 20c, and the third bending part 26d of the ridge 20d, which are on the virtual line 30a, are , preferably the same. Incidentally, in the case of FIGS. 2 to 4, the bending angles of all bending portions are 90°.

The pitch L of the ridges 20 (the shortest distance between the vertices of two adjacent ridges 20, see FIG. 6) is, for example, 0.4 mm or more and 5.0 mm or less. Further, the height H (see FIG. 6) of the ridge 20 is, for example, 0.2 mm or more and 2.0 mm or less.

The features of such ridges 20 and virtual lines 30 are common to the two serrations 14 of the annular decorative region 11. The shapes of the ridge 20 and the virtual line 30 have two-fold (180°) rotational symmetry. Further, when the decorative regions 11 are provided on both sides in the width direction of the pneumatic tire 1, the characteristics of the ridge 20 and the virtual line 30 may be common to the decorative regions 11 on both sides.

Further, in FIG. 2, the portion of the decorative area 11 other than the serrations 14 is a smooth surface, but letters or patterns may be formed on this portion.

Next, the effects of this embodiment will be explained.

The ridge 20 of this embodiment is bent at the bending portion and extends in the tire radial direction without being interrupted midway. Therefore, each ridge 20 functions as one long reinforcing rib, suppressing deflection of the sidewall portion 10 when the pneumatic tire 1 rolls, and suppressing the occurrence of cracks in the sidewall portion 10. . Therefore, the appearance of the pneumatic tire 1 during use is unlikely to deteriorate.

Further, a plurality of virtual lines 30 connecting the closest bent portions are formed in one serration 14, but since the shapes of adjacent virtual lines 30 are different, non-uniformity occurs in the pattern of the serrations 14. When the pattern of the serrations 14 is non-uniform, unnecessary irregularities and cracks on the surface of the sidewall portion 10 become less noticeable. In addition, if there is a characteristic part of the non-uniform pattern (for example, a part where the distance between the virtual lines 30 is narrow), that part tends to attract people's attention. Unevenness and cracks become even less noticeable. Therefore, the appearance of the pneumatic tire 1 is good when it is not in use, and the appearance of the pneumatic tire 1 during use is also less likely to deteriorate.

Further, since the bending angle of the bending portion is 90° or more, strain is less likely to be concentrated at the bending portion, and cracks are less likely to occur starting from the bending portion.

In addition, if the pitch L of the ridges 20 is 0.4 mm or more and 5.0 mm or less, or if the height H of the ridges 20 is 0.2 mm or more and 2.0 mm or less, the surface of the sidewall portion 10 may become unnecessary. It is particularly effective in making unevenness and cracks less noticeable.

The above embodiments are illustrative, and the scope of the invention is not limited to the above embodiments. Various changes can be made to the above embodiments without departing from the spirit of the invention.

For example, in the embodiment described above, the serrations 14 are provided at two opposing locations in the annular decorative region 11, but the serrations 14 may be provided at three or more locations in the circumferential direction of the annular decorative region 11. In any case, it is preferable that the serrations 14 be provided over half or more of the annular decorative area 11 in the circumferential direction. Further, the entire decorative area 11 may be part of the serrations 14.

Further, the forms of the ridge 20 and the virtual line 30 are not limited to the above embodiments. The number and position of the bending angles of the ridge 20, the extension direction (inclination direction) of each line portion of the ridge 20, etc. can be changed into various forms. Further, the shape of the virtual line 30 formed by connecting the bent portions of the ridge 20 can also be changed into various shapes.

Further, the virtual line is not limited to a curved line, and may be a straight line when viewed from the tire axis direction, for example. When the imaginary lines are linear, "the shapes of adjacent imaginary lines are different" means that the inclination angles of the radially inner edge 12 with respect to the tangential direction are different between the adjacent imaginary lines.

DESCRIPTION OF SYMBOLS 1... Pneumatic tire, 2... Carcass ply, 2a... Turned part, 2b... Rolled up end, 3... Rubber chafer, 4... Belt, 5... Belt reinforcement layer, 6... Tread rubber, 7... Sidewall rubber, 8... Inner liner, 9... Bead part, 10... Sidewall part, 11... Decoration area, 12... Inner diameter side edge, 13... Outer diameter side edge, 14... Serration, 20, 20a, 20b, 20c, 20d, 20e... Ridge, 21a, 21b, 21c, 21d, 21e...first bent part, 22a, 22b, 22c, 22d, 22e...second bent part, 23a, 23b, 23c, 23d, 23e...first line part, 24a, 24b , 24c, 24d, 24e...second line part, 25a, 25b, 25c, 25d, 25e...third line part, 26b, 26d...third bent part, 27b, 27d...fourth line part, 30...imaginary line, 30a...Virtual line, 30b...Virtual line

Claims (3)

A pneumatic tire in which serrations extending in the tire circumferential direction are provided on at least one of the sidewall portions on both sides in the tire width direction, and a plurality of ridges that are convex stripes are arranged in the tire circumferential direction on the serrations,
Each of the ridges extends in the tire radial direction while having a bent portion, and a plurality of imaginary lines are formed connecting the closest bent portions of the adjacent ridges, and each of the imaginary lines is a curve, and The shape of the virtual line is different,
The serrations are provided in a part of a decorative area sandwiched between a small diameter circular inner diameter side edge and a large diameter circular outer diameter side edge,
a plurality of the ridges extending from the inner diameter edge to the outer diameter edge;
A pneumatic tire , wherein each of the adjacent imaginary lines extends from the inner diameter side edge to the outer diameter side edge . Each of the ridges is formed with at least a first bent portion on the inner side in the tire radial direction, and a second bent portion on the outer side in the tire radial direction than the first bent portion,
In the range of the plurality of ridges in which the first line portions from the tire radially inner end to the first bent portion face the same direction, an imaginary line connecting the first bent portion and the second bent portion The pneumatic tire according to claim 1, wherein the imaginary lines connecting the two are not parallel to each other. The pneumatic tire according to claim 1 or 2, wherein the bending angle of the bending portion of the ridge is 90° or more.

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