JP7368214B2 - tire - Google Patents

Description

The present invention relates to tires.

BACKGROUND ART Conventionally, tires are known in which a hollow portion that appears as a groove when the wear of the tread progresses is arranged inside a land portion of the tread. Patent Document 1 describes this type of tire.

Japanese Patent Application Publication No. 2002-67620

According to the tire described in Patent Document 1, when the wear of the land portion progresses, the hollow portion appears as a groove on the surface of the land portion, so that deterioration in drainage performance can be suppressed. However, in a tire in which a cavity is divided inside a land part as described in Patent Document 1, the state before the cavity appears as a groove on the surface of the land part (hereinafter simply referred to as "normal state") There is still room for improvement regarding drainage performance. In order to improve drainage performance, it is conceivable to form a flow path from the surface of the land portion to the cavity, but the flow path may increase rolling resistance and deteriorate fuel efficiency.

The present invention is capable of improving drainage performance even when the land part is in its normal state regardless of the progress of wear, and also has a hollow part inside the land part that can suppress an increase in rolling resistance in the land part's normal state. The purpose is to provide compartmentalized tires.

A tire according to a first aspect of the present invention is a tire including a rib-shaped land portion on a tread surface defined between two circumferential grooves extending along the circumferential direction of the tire, wherein the rib-shaped land portion An elongated cavity extending along the tire circumferential direction is formed inside the land part, and a position on one side in the tire width direction with respect to the cavity on the surface of the rib-shaped land part, A first slit portion extending from a first linear opening extending along the circumferential direction of the tire to the hollow portion, and the other side of the surface of the rib-like land portion in the tire width direction with respect to the hollow portion. A second slit portion extending from a second linear opening formed at a position and extending along the tire circumferential direction to the cavity portion is defined.
As a result, drainage performance can be improved even in the normal state of the land area, regardless of the progress of wear. Further, an increase in rolling resistance can be suppressed in the normal state of the land portion.

In one embodiment of the present invention, at least a portion of the first slit portion extends inside the rib-like land portion at an angle to one side with respect to the tire radial direction in a cross-sectional view in the tire width direction. ing.
Thereby, it is possible to suppress the occurrence of a rigidity level difference in the tire width direction.

In one embodiment of the present invention, at least a portion of the second slit portion extends inside the rib-like land portion at an angle to the other side with respect to the tire radial direction when viewed in cross section in the tire width direction. ing.
Thereby, it is possible to suppress the occurrence of a rigidity level difference in the tire width direction.

In one embodiment of the present invention, inside the rib-like land portion, a surface of the rib-like land portion extends across the one side and the other side in the tire width direction with respect to the cavity portion. A third slit portion extending from the third linear opening to the cavity portion is defined.
Thereby, drainage performance under normal conditions can be further improved.

In one embodiment of the present invention, the first slit portion and the second slit portion are formed by the third slit portion over the entire area of the first slit portion and the second slit portion in the tire radial direction. It's communicating.
Thereby, drainage performance under normal conditions can be further improved.

As one embodiment of the present invention, each of the first slit portion and the second slit portion is arranged in plurality at predetermined intervals in the tire circumferential direction, and the first slit portion and the second slit portion are arranged at predetermined intervals in the tire circumferential direction. , are arranged in a staggered manner along the tire circumferential direction on both sides of the tire width direction sandwiching the cavity portion, and the third slit portion is located on one side of the first slit portion in the tire circumferential direction. The one end is connected to the other end of the second slit portion, which is located on the other side in the tire circumferential direction and is closest to the one end of the first slit portion.
This makes it easy to take out the mold after vulcanization molding, even when a mold is used to form the cavity, first slit, second slit, and third slit during vulcanization molding of a tire. .

In one embodiment of the present invention, at least one of the first slit section, the second slit section, and the third slit section is adjacent to the surface of the rib-like land section in the slit extending direction. A wide portion is formed in which the slit width is wider than the position.
Thereby, drainage performance under normal conditions can be further improved.

According to the present invention, there is provided a cavity inside the land part that can improve drainage performance even in the normal state of the land part regardless of the progress of wear, and can suppress an increase in rolling resistance in the normal state of the land part. It is possible to provide a tire having partitioned sections.

1 is a cross-sectional view in the tire width direction of a tire as an embodiment of the present invention. FIG. 2 is a developed view showing a part of the tread surface of the tread portion of the tire shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line II in FIG. 2. FIG. 3 is a sectional view taken along line II-II in FIG. 2. FIG. It is a figure which shows the example of a modification of the 1st slit part and the 2nd slit part of the tire shown in FIG. It is a figure which shows the example of a modification of the 1st slit part, the 2nd slit part, and the 3rd slit part of the tire shown in FIG. It is a figure which shows the example of a modification of the 3rd slit part of the tire shown in FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a tire according to the present invention will be illustrated with reference to the drawings. Common members and parts in each figure are designated by the same reference numerals.

In this specification, the term "tread surface" refers to the tread surface when a tire assembled to a rim and filled with a specified internal pressure is rolled under a maximum load (hereinafter also referred to as "maximum load state"). , refers to the entire circumference of the tire that comes into contact with the road surface. Furthermore, the term "tread edge" refers to the outer edge of the tread surface in the tire width direction.

In this specification, "rim" refers to an industrial standard that is valid in the region where tires are produced and used, such as the JATMA YEAR BOOK of JATMA (Japan Automobile Tire Association) in Japan, and ETRTO (The European Tire Association) in Europe. Standard rims in applicable sizes (ETRTO's STANDARDS MANUAL) are listed or will be listed in the YEAR BOOK, etc. of TRA (The Tire and Rim Association, Inc.) in the United States. Measuring Rim (Design Rim in TRA's Year Book) refers to a rim with a width that corresponds to the tire bead width if the size is not listed in the above industrial standards. In addition to the current size, "rim" includes sizes that may be included in the above industrial standards in the future. Examples of "sizes to be described in the future" include the sizes described as "FUTURE DEVELOPMENTS" in ETRTO's STANDARDS MANUAL 2013 edition.

In this specification, "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating, as described in industrial standards such as the above-mentioned JATMA YEAR BOOK, In the case of sizes not listed in the above industrial standards, this refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity specified for each vehicle on which the tire is installed. Additionally, in this specification, "maximum load" refers to the load corresponding to the maximum load capacity of tires of applicable sizes listed in the above industrial standards, and in the case of tires of sizes not listed in the above industrial standards. shall refer to the load corresponding to the maximum load capacity specified for each vehicle on which the tire is installed.

FIG. 1 is a diagram showing a pneumatic tire 1 (hereinafter simply referred to as "tire 1") as an embodiment of the tire according to the present invention. FIG. 1 shows a cross section of a tire 1 in the tire width direction on a plane including the central axis.

As shown in FIG. 1, the tire 1 includes a tread portion 1a, a pair of sidewall portions 1b extending inward in the tire radial direction A from both ends of the tread portion 1a in the tire width direction B, and each sidewall portion 1b. A pair of bead portions 1c provided at the inner end in the tire radial direction A. The tire 1 of this embodiment is a tubeless type radial tire, but its configuration is not particularly limited. Here, the "tread portion 1a" means a portion sandwiched between both tread ends TE in the tire width direction B. Moreover, the "bead portion 1c" means a portion in the tire radial direction A where a bead member 3, which will be described later, is located. The "sidewall portion 1b" means the portion between the tread portion 1a and the bead portion 1c.

The tire 1 of this embodiment includes a bead member 3, a carcass 4, an inclined belt 5, a circumferential belt 6, tread rubber 7, side rubber 8, and an inner liner 9. The bead member 3 includes a bead core 3a and a bead filler 3b.

The bead member 3 includes a bead core 3a and a bead filler 3b disposed on the outside of the bead core 3a in the tire radial direction A. The tire 1 includes a carcass 4 spanning between a pair of bead cores 3a. The carcass 4 is composed of a carcass ply in which cords made of steel or the like are arranged. Further, the tire 1 includes an inclined belt 5 disposed outside the crown portion of the carcass 4 in the tire radial direction A. The inclined belt 5 is composed of a belt ply in which cords made of organic fiber, steel, etc. are arranged. In the belt ply constituting the inclined belt 5, the cords extend at an angle of 10° or more with respect to the tire circumferential direction C. There may be two or more belt plies constituting the inclined belt 5. The tire 1 also includes a circumferential belt 6 disposed outside the inclined belt 5 in the tire radial direction A. The circumferential belt 6 is composed of belt plies in which cords made of organic fibers, steel, etc. are arranged. In the belt ply that constitutes the circumferential belt 6, the cord extends along the tire circumferential direction C. "The cord extends along the tire circumferential direction" means that the inclination angle of the cord with respect to the tire circumferential direction C is 0° or more and less than 10°. There may be two or more belt plies constituting the circumferential belt 6.

The tire 1 also includes a tread rubber 7 disposed on the outside of the circumferential belt 6 in the tire radial direction A, and a side rubber 8 disposed on the outside of the side portion of the carcass 4 in the tire width direction B. . Furthermore, the tire 1 includes an inner liner 9 laminated on the inner surface of the carcass 4.

Although the tire 1 of this embodiment has the above-mentioned cross-sectional structure in the cross-section in the tire width direction, the tire is not limited to this cross-sectional structure, and may have another cross-sectional structure. Moreover, although the tire 1 of this embodiment has a symmetrical structure with respect to the tire equatorial plane CL, it is not limited to this structure, and may be a tire that is asymmetrical with respect to the tire equatorial plane CL.

Further, the tire 1 includes a rib-shaped land portion 31 on the tread surface T that is defined between two circumferential grooves 21 extending along the tire circumferential direction C. "Circumferential groove" is a section where the minimum width at the groove edge is 2 mm or more when an unused tire is mounted on the applicable rim, filled with the specified internal pressure, and under no load. This is one type of groove, and refers to an annular groove that extends along the tire circumferential direction C over the entire tire circumferential direction C among the partition grooves. The circumferential groove 21 of this embodiment extends parallel to the tire circumferential direction C, but it is sufficient that it extends along the tire circumferential direction C, and at an angle of 5° or less with respect to the tire circumferential direction C. It may be inclined. Furthermore, the circumferential grooves 21 of the present embodiment are configured to extend linearly along the tire circumferential direction C when the tread surface T is viewed in development, but are not limited to this configuration. It may extend in a zigzag or wavy pattern. Furthermore, a "rib-shaped land portion" is defined as a land portion that is partitioned between two circumferential grooves and is divided into separate land portions in the tire circumferential direction C by a partition groove that extends in the tire width direction B. It means an annular land portion that extends over the entire area in the circumferential direction C of the tire.

More specifically, the tread surface T of the tire 1 of this embodiment is provided with four circumferential grooves 21 and three rib-shaped land portions 31 partitioned between these four circumferential grooves 21. It is being The three rib-like land portions 31 of the present embodiment include a center land portion 32a through which the tire equatorial plane CL passes, and two intermediate land portions 32b adjacent to each other on both sides of the center land portion 32a in the tire width direction B. Become. Furthermore, among the four circumferential grooves 21, each of the two circumferential grooves 21 on both outer sides in the tire width direction B defines a shoulder land portion 32c that does not correspond to the rib-like land portion 31 between the two circumferential grooves 21 and the tread end TE. are doing.

FIG. 2 is a developed view showing a part of the tread surface T of the tread portion 1a of the tire 1. As shown in FIG. Specifically, FIG. 2 is a developed view showing the center land portion 32a and its vicinity on the tread surface T. FIG. 3 is a sectional view taken along line II in FIG. 2. FIG. 4 is a sectional view taken along line II-II in FIG.

As shown in FIGS. 1 to 4, inside the center land portion 32a as the rib-like land portion 31, there are a hollow portion 41, a first slit portion 42, a second slit portion 43, and a third slit portion 44. and are divided. The term "slit portion" refers to a groove that does not correspond to a partition groove and has a maximum width of 2 mm or less. In this embodiment, the center land portion 32a serving as the rib-like land portion 31 is provided with the above-described hollow portion 41, first slit portion 42, second slit portion 43, and third slit portion 44; It may be the land portion 31, and is not limited to the center land portion 32a. Therefore, the hollow portion 41, the first slit portion 42, the second slit portion 43, and the third slit portion 44 may be provided in another rib-shaped land portion 31 such as the intermediate land portion 32b. Therefore, hereinafter, when the center land portion 32a and the intermediate land portion 32b are not distinguished, they will simply be referred to as "rib-like land portions 31."

As shown in FIG. 2, the cavity 41 is an elongated hollow part extending along the tire circumferential direction C. The hollow portion 41 of this embodiment extends in parallel to the tire circumferential direction C within the rib-like land portion 31, but it is sufficient that the hollow portion 41 extends along the tire circumferential direction C. and may be inclined at an angle of 5° or less. Moreover, the cavity 41 of this embodiment may extend along the tire circumferential direction C in an arch shape, a zigzag shape, or a wave shape.

As shown in FIGS. 1 to 4, the first slit portion 42 extends from the first linear opening 42a formed on the surface of the rib-like land portion 31 to the cavity portion 41. As shown in FIGS. The first linear opening 42a is formed on the surface of the rib-like land portion 31 at a position on one side (on the left side in FIGS. 1 to 4) in the tire width direction B with respect to the cavity 41. Moreover, the first linear opening 42a extends along the tire circumferential direction C.

Further, as shown in FIGS. 1 to 4, the second slit portion 43 extends from the second linear opening 43a formed in the surface of the rib-like land portion 31 to the cavity portion 41. The second linear opening 43a is formed on the surface of the rib-like land portion 31 at a position on the other side in the tire width direction B (on the right side in FIGS. 1 to 4) with respect to the cavity 41. Moreover, the second linear opening 43a extends along the tire circumferential direction C.

Note that, as shown in FIG. 2, the first linear opening 42a and the second linear opening 43a of this embodiment extend parallel to the tire circumferential direction C on the surface of the rib-like land portion 31. , it is sufficient that it extends along the tire circumferential direction C. Moreover, the first linear opening 42a and the second linear opening 43a of the present embodiment may extend in an arched shape, a zigzag shape, or a wave shape along the tire circumferential direction C.

In this way, the rib-like land portion 31 of the tire 1 is provided with a first slit portion 42 and a second slit portion 43 that extend from the cavity 41 to the surface of the rib-like land portion 31 . Therefore, even in the normal state before the cavity 41 appears as a groove on the surface of the rib-like land portion 31, the first slit portion 42 and the second slit are formed in the cavity 41 from the surface of the rib-like land portion 31. Water enters through the portion 43. Therefore, drainage performance can be improved even in a normal state before wear progresses.

Further, in the tire 1, the first linear opening 42a and the second linear opening 43a of the first slit part 42 and the second slit part 43 that extend from the cavity part 41 to the surface of the rib-like land part 31 are arranged in the tire width direction B. , it is formed at a different position from the cavity 41. Therefore, in the tire 1, compared to a configuration in which the linear opening of the slit part is formed at the same position as the cavity part 41 in the tire width direction B on the surface of the rib-like land part 31, the cavity is formed in the tire width direction B. It is possible to suppress a local decrease in the compression rigidity of the rib-like land portion 31 at the position where the portion 41 is provided. Therefore, it is possible to suppress an increase in rolling resistance in a normal state before wear progresses.

Further, the first slit portion 42 and the second slit portion 43 are arranged on both sides of the tire width direction B with the cavity 41 interposed therebetween. Therefore, it is possible to suppress the compression rigidity from becoming non-uniform on both sides of the tire width direction B with respect to the cavity portion 41. Thereby, it is possible to suppress the formation of a microspace in which water can accumulate between the surface of the rib-like land portion 31 and the road surface at the position where the cavity portion 41 is provided in the tire width direction B. As a result, drainage performance under normal conditions before wear progresses can be further improved.

As described above, the cavity 41, the first slit 42, and the second slit 43 described above are partitioned inside the rib-like land portion 31, so that not only when the wear progresses but also when the wear progresses Drainage performance can be improved even in the previous normal state, and an increase in rolling resistance in the normal state can be suppressed.

The details of the cavity 41, the first slit 42, the second slit 43, and the third slit 44 of this embodiment will be described below with reference to FIGS. 2 to 4.

As shown in FIGS. 1, 3, and 4, the inner wall of the rib-like land portion 31 that partitions the cavity 41 of this embodiment has a substantially circular shape in a cross-sectional view perpendicular to the extending direction of the cavity 41. However, the cross-sectional shape is not limited to this. The cross-sectional shape of the inner wall of the rib-like land portion 31 that partitions the cavity 41 may be, for example, an oval shape or a polygonal shape such as a triangular shape.

Although the cavity 41 of this embodiment is an annular hollow section partitioned over the entire area in the tire circumferential direction C, it is not limited to this configuration. The cavity 41 may be divided into only a partial region in the tire circumferential direction C.

The outer end of the cavity 41 in the tire radial direction A is preferably located on the outer side in the tire radial direction A than the groove bottoms of the two circumferential grooves 21 that partition the rib-like land portion 31 including the cavity 41. . By doing so, even if the surface of the rib-like land portion 31 is worn, the hollow portion 41 appears as a groove on the tread surface T before the two circumferential grooves 21 completely disappear. Therefore, when the tread surface T wears out, a predetermined drainage performance can be ensured. The outer end of the cavity 41 in the tire radial direction A is 2 mm or more outward in the tire radial direction A than the groove bottoms of the two circumferential grooves 21 that partition the rib-like land portion 31 including the cavity 41. It is preferable that the tire be located outside the tire radial direction A by 3 mm or more. By doing so, a predetermined drainage performance can be more reliably ensured when the tread surface T wears out.

Further, it is preferable that the inner end of the cavity 41 in the tire radial direction A is located on the inner side in the tire radial direction A than the groove bottoms of the two circumferential grooves 21 that partition the rib-like land portion 31. By doing so, even if the surface of the rib-like land portion 31 is worn and the two circumferential grooves 21 completely disappear, the grooves formed from the hollow portion 41 remain on the tread surface T. , a predetermined drainage performance can be maintained.

The maximum length of the cavity 41 in the tire radial direction A is preferably 1 mm or more. By doing so, the drainage performance of the grooves formed from the cavity 41 when wear progresses can be improved. Further, the maximum length of the cavity 41 in the tire radial direction A is preferably 7 mm or less. By doing so, it is possible to suppress the compression rigidity of the rib-like land portion 31 including the cavity portion 41 from decreasing significantly.

At least a portion of the first slit portion 42 extends at an angle to one side (to the left in FIGS. 1 to 4) with respect to the tire radial direction A inside the rib-like land portion 31 in a cross-sectional view in the tire width direction. It is preferable that you do so. In the region of the rib-like land portion 31 where the above-mentioned inclined portion of the first slit portion 42 is provided, a sudden change in compression rigidity is unlikely to occur in the tire width direction B. That is, by providing the first slit portion 42 with the above-mentioned inclined portion, it is possible to suppress the occurrence of a rigid step in the tire width direction B. Therefore, as shown in FIG. 1, FIG. 3, and FIG. 1 to 4) is particularly preferable.

Note that, for the same reason as the first slit portion 42 described above, at least a portion of the second slit portion 43 is located on the other side with respect to the tire radial direction A inside the rib-like land portion 31 in a cross-sectional view in the tire width direction. It is preferable that it extends in an inclined direction (to the right in FIGS. 1 to 4). Further, as shown in FIGS. 1, 3, and 4, the entire second slit portion 43 is located inside the rib-like land portion 31 on the other side with respect to the tire radial direction A (in the cross-sectional view in the tire width direction). 1 to 4) is particularly preferable.

Moreover, as shown in FIG. 2, the first slit part 42 and the second slit part 43 of this embodiment are arranged at different positions in the tire circumferential direction C. More specifically, the first slit portions 42 and the second slit portions 43 of this embodiment are alternately arranged in the tire circumferential direction C. In other words, the second slit portion 43 is not provided in the area in the tire circumferential direction C where the first slit portion 42 of this embodiment is provided. Here, "the first slit part and the second slit part are arranged at different positions in the tire circumferential direction" means that at least a part of the slit part of one of the first slit part and the second slit part is located at different positions in the tire circumferential direction. It is sufficient that the slit portion is located at a different position in the tire circumferential direction. That is, a portion of the first slit portion 42 may overlap a portion of the second slit portion 43 in the tire circumferential direction C. In other words, a portion of the first slit portion 42 may be located at the same position as a portion of the second slit portion 43 in the tire circumferential direction C.

Further, as shown in FIGS. 2 and 4, inside the rib-like land portion 31, in addition to the above-mentioned cavity 41, first slit portion 42, and second slit portion 43, a third slit portion 44 is partitioned. has been done. As shown in FIG. 2 , the third slit portion 44 extends from the third linear opening 44 a formed on the surface of the rib-like land portion 31 to the cavity portion 41 . The third linear openings 44a are formed on the surface of the rib-like land portion 31 on one side (the left side in FIGS. 1 to 4) of the tire width direction B with respect to the cavity 41, and on the other side (the left side in FIGS. 1 to 4). right side) and extends across the.

As shown in FIG. 2, the third linear opening 44a of the present embodiment extends parallel to the tire width direction B on the surface of the rib-like land portion 31; The present direction is not limited to the direction of this embodiment. The third linear openings 44a are formed on the surface of the rib-like land portion 31 on one side (the left side in FIGS. 1 to 4) of the tire width direction B with respect to the cavity 41, and on the other side (the left side in FIGS. 1 to 4). It suffices if it extends across the right side) and . Therefore, the third linear opening 44a may extend in a direction inclined with respect to the tire width direction B on the surface of the rib-like land portion 31. Details of the third linear opening inclined with respect to the tire width direction B will be described later (see FIG. 7). Moreover, although the third linear opening 44a in this embodiment extends linearly, it may extend in an arcuate shape, a zigzag shape, or a wave shape.

In addition to the first slit portion 42 and the second slit portion 43, a third slit portion 44 that extends from the third linear opening 44a to the cavity portion 41 is defined inside the rib-like land portion 31, so that the rib Compared to a configuration in which only the first slit portion 42 and the second slit portion 43 are partitioned inside the land portion 31, the drainage performance in the normal state can be further improved.

Furthermore, as shown in FIG. 4, the first slit section 42 and the second slit section 43 of this embodiment are arranged so that the first slit section 42 and the second slit section 43 are arranged in the tire radial direction A by the third slit section 44. It communicates throughout the entire area. Therefore, since water can move between the first slit section 42, the second slit section 43, and the third slit section 44, the first slit section 42, the second slit section 43, and the third slit section 44 Drainage performance under normal conditions can be further improved compared to a configuration in which there is no communication.

Further, the third slit portion 44 communicates with the cavity portion 41 and also communicates with the first slit portion 42 and the second slit portion 43 over the entire area of the first slit portion 42 and the second slit portion 43 in the tire radial direction A. communicate with. Therefore, even if a mold is used to form the cavity 41, the first slit 42, the second slit 43, and the third slit 44 during vulcanization molding of the tire 1, the Easy to take out the mold. However, the method of manufacturing the tire 1 is not particularly limited. Therefore, the method of forming the hollow portion 41, the first slit portion 42, the second slit portion 43, and the third slit portion 44 is not particularly limited, and may be formed using, for example, a 3D printer.

Further, as shown in FIG. 2, a plurality of first slit portions 42 and second slit portions 43 of this embodiment are arranged at predetermined intervals in the tire circumferential direction C. More specifically, the first slit portion 42 of this embodiment is located on the surface of the rib-like land portion 31 at a position on one side in the tire width direction B (on the left side in FIGS. 1 to 4) relative to the hollow portion 41. , are arranged at predetermined intervals along the tire circumferential direction C. Further, the second slit portion 43 of the present embodiment is located on the surface of the rib-like land portion 31 at a position on the other side in the tire width direction B (on the right side in FIGS. 1 to 4) than the cavity portion 41 in the tire circumferential direction. They are arranged at predetermined intervals along C. Furthermore, as shown in FIG. 2, the first slit part 42 and the second slit part 43 are arranged in a staggered manner along the tire circumferential direction C on both sides of the tire width direction B sandwiching the cavity part 41. Since the first slit portion 42 and the second slit portion 43 are arranged on both sides of the tire width direction B with the cavity 41 in between, as described above, the drainage performance can be improved in the normal state before wear progresses. , suppression of increase in rolling resistance can be realized. Furthermore, by arranging the first slit parts 42 and the second slit parts 43 in a staggered manner, it is compared with a configuration in which the first slit parts 42 and the second slit parts 43 are arranged to extend parallel to the tire circumferential direction C. Thus, the compression rigidity of the rib-like land portion 31 at the position where the cavity portion 41 is provided in the tire width direction B can be further increased. That is, it is possible to further improve the drainage performance and suppress the increase in rolling resistance in the normal state before the progress of wear.

Furthermore, as shown in FIG. 2, the third slit portion 44 of this embodiment has one end 42b located on one side in the tire circumferential direction C of the first slit portion 42, and one end 42b of the second slit portion 43 located on one side of the tire circumferential direction C. It is located on the other side in the circumferential direction C and is connected to the other end 43c closest to the one end 42b of the first slit portion 42. Further, as shown in FIG. 2, the third slit portion 44 of the present embodiment includes the other end 42c of the first slit portion 42 located on the other side in the tire circumferential direction C, and the second end 42c of the second slit portion 43 located on the other side of the tire circumferential direction C. It is located on one side in the circumferential direction C and is connected to one end 43b closest to the other end 42c of the first slit portion 42. In addition, in this embodiment, for convenience of explanation, the above-mentioned "one side in the tire circumferential direction C" is referred to as the "lower side in FIG. 2", and the above-mentioned "other side in the tire circumferential direction C" is referred to as the "upper side in FIG. 2". described, but not limited to. Therefore, the "one side in the tire circumferential direction C" may be referred to as the "upper side in FIG. 2", and the "other side in the tire circumferential direction C" may be referred to as the "lower side in FIG. 2".

In this way, the slit ends of the first slit portion 42 and the second slit portion 43 arranged in a staggered manner in the slit extending direction are connected by the third slit portion 44, so that the surface of the rib-like land portion 31 is A continuous slit extending in the form of a pulse wave is formed. Therefore, even if a mold is used to form the cavity 41, the first slit 42, the second slit 43, and the third slit 44 during vulcanization molding of the tire 1, the It becomes easier to take out the mold. However, as described above, the method for manufacturing the tire 1 is not particularly limited.

The slit widths of the first slit portion 42, the second slit portion 43, and the third slit portion 44 of this embodiment are constant regardless of the position in the tire radial direction A. The slit widths of the first slit portion 42, the second slit portion 43, and the third slit portion 44 are not particularly limited as long as they are less than 2 mm, but may be in the range of 0.3 mm to 1 mm, for example. Further, the slit widths of the first slit portion 42, the second slit portion 43, and the third slit portion 44 may vary depending on the position in the tire radial direction A, as long as they are less than 2 mm.

The tire according to the present invention is not limited to the specific configuration shown in the embodiments described above, and various modifications and changes can be made without departing from the scope of the claims. The first slit portion 42 and the second slit portion 43 of the tire 1 described above are composed only of inclined portions that extend obliquely with respect to the tire radial direction A in the cross-sectional view shown in FIG. It is not limited to the configuration. FIG. 5 is a cross-sectional view showing a first slit part 142 and a second slit part 143 as a modification of the first slit part 42 and second slit part 43 of the tire 1. The cross section shown in FIG. 5 is a cross section at the same position as FIG. 3. The first slit portion 142 includes a vertical portion 151 extending along the tire radial direction A from the first linear opening 142a, and a tire diameter portion 151 that extends inside the tire radial direction A of the vertical portion 151 and continues to the cavity portion 41. It is configured with a slope portion 152 that slopes to one side (left side in FIG. 5) with respect to direction A. The second slit portion 143 includes a vertical portion 153 that extends from the second linear opening 143a along the tire radial direction A, and a tire diameter portion 153 that extends inside the tire radial direction A of the vertical portion 153 and continues to the cavity portion 41. It is configured with a slope portion 154 that slopes to the other side (to the right in FIG. 5) with respect to direction A. Such a first slit portion 142 and second slit portion 143 may be used. The vertical portion 151 and the inclined portion 152 of the first slit portion 142 may have different slit widths. From the viewpoint of improving drainage performance when wear progresses, it is preferable that the slit widths of the vertical portion 151 and the inclined portion 152 gradually increase toward the inside in the tire radial direction A. The vertical portion 153 and the inclined portion 154 of the second slit portion 143 may also have different slit widths. Furthermore, from the viewpoint of improving drainage performance during wear progression, it is preferable that the slit widths of the vertical portion 153 and the inclined portion 154 gradually increase toward the inside in the tire radial direction A. As mentioned above, from the viewpoint of suppressing the rigidity difference in the tire width direction B, the entire first slit part 42 and the second slit part 43 shown in FIG. In this case, it is preferable to extend inside the rib-like land portion 31 at an angle with respect to the tire radial direction A.

Further, FIG. 6 shows a first slit section 242, a second slit section 243, and a third slit section 244 as a modification of the first slit section 42, second slit section 43, and third slit section 44 described above. It is a diagram. FIG. 6 is a developed view showing a part of the tread surface T. Specifically, FIG. 6 is a developed view showing the center land portion 32a and its vicinity on the tread surface T. The first slit section 242, the second slit section 243, and the third slit section 244 shown in FIG. The configuration is different in the points provided, and the other configurations are the same.

The first slit portion 242 shown in FIG. 6 is formed with a wide portion 242d in which the slit width is wider than the adjacent position in the slit extending direction (tire circumferential direction C in FIG. 6) on the surface of the rib-like land portion 31. has been done. More specifically, in the first slit portion 242 shown in FIG. 6, at the center position in the slit extending direction, there is a position adjacent in the direction in which the slit width is wider than that on both sides (tire circumferential direction C in FIG. 6). A wide portion 242d having a wider slit width is formed. The slit width in the wide portion 242d is not particularly limited as long as it is less than 2 mm, but can be set to be greater than 1 mm and less than 2 mm, for example. The slit width of the wide portion 242d is larger than the slit width at an adjacent position not only on the surface of the rib-like land portion 31 but also inside the rib-like land portion 31 in the slit extending direction. The wide portion 242d extends to the hollow portion 41. By doing so, the drainage performance of the first slit portion 242 can be further improved.

In the example shown in FIG. 6, similar wide portions 243d and 244d are formed in the second slit portion 243 and the third slit portion 244, but the configuration is not limited to this. The wide portion may be formed in only one of the first slit portion 242, the second slit portion 243, and the third slit portion 244, or the wide portion may be formed in only any two. However, from the viewpoint of drainage performance, as shown in FIG. 6, it is preferable that wide portions 242d, 243d, and 244d are formed in all of the first slit portion 242, the second slit portion 243, and the third slit portion 244. .

Moreover, the number of wide portions provided in each of the first slit portion 242, the second slit portion 243, and the third slit portion 244 may be one or multiple.

Furthermore, the wide portion shown in FIG. 6 may be formed in each slit portion of the modified example shown in FIG.

Further, FIG. 7 is a diagram showing a third slit portion 144 as a modification of the third slit portion 44. As shown in FIG. Similar to FIG. 2, FIG. 7 is a developed view showing the center land portion 32a and its vicinity in the tread surface T of the tread portion 1a of the tire 1. Like the third slit portion 144 shown in FIG. 7, the third linear opening 144a formed on the surface of the rib-like land portion 31 may extend obliquely with respect to the tire width direction B. .

Moreover, the first slit part 42, the second slit part 43, and the third slit part 144 shown in FIG. 7 may have a wide part as shown in FIG. 6. In this way, the tire according to the present invention may be a tire constructed by appropriately combining the elements shown in FIGS. 1 to 7.

The present invention relates to tires.

1: Tire, 1a: Tread portion, 1b: Sidewall portion, 1c: Bead portion, 3: Bead member, 3a: Bead core, 3b: Bead filler, 4: Carcass, 5: Inclined belt, 6: Circumferential belt, 7: tread rubber, 8: side rubber, 9: inner liner, 21: circumferential groove, 31: rib-shaped land section, 32a: center land section, 32b: intermediate land section, 32c: shoulder land section, 41: hollow section, 42, 142, 242: first slit portion, 42a, 142a: first linear opening, 42b: one end of the first slit portion in the tire circumferential direction, 42c: other end of the first slit portion in the tire circumferential direction, 43, 143 , 243: second slit portion, 43a, 143a: second linear opening, 43b: one end of the second slit portion in the tire circumferential direction, 43c: the other end of the second slit portion in the tire circumferential direction, 44, 144, 244: Third slit portion, 44a, 144a: Third linear opening, 151: Vertical portion of first slit portion, 152: Inclined portion of first slit portion, 153: Vertical portion of second slit portion, 154: No. Slanted part of the second slit part, 242d: Wide part of the first slit part, 243d: Wide part of the second slit part, 244d: Wide part of the third slit part, A: Tire radial direction, B: Tire width direction, C : Tire circumferential direction, CL: Tire equatorial plane, T: Tread surface, TE: Tread edge

Claims (7)

A tire comprising a rib-like land portion on a tread surface defined between two circumferential grooves extending along the circumferential direction of the tire,
Inside the rib-like land portion,
a long cavity extending along the circumferential direction of the tire;
A first linear opening formed on the surface of the rib-shaped land portion at a position on one side in the tire width direction with respect to the hollow portion and extending along the tire circumferential direction extends from the first linear opening to the hollow portion. a first slit portion;
A second linear opening formed on the surface of the rib-shaped land portion at a position on the other side in the tire width direction with respect to the hollow portion and extending along the tire circumferential direction extends from the second linear opening to the hollow portion. A tire having a second slit section. According to claim 1, at least a portion of the first slit portion extends at an angle to one side with respect to the tire radial direction inside the rib-like land portion in a cross-sectional view in the tire width direction. tire. According to claim 2, at least a portion of the second slit portion extends inside the rib-like land portion at an angle to the other side with respect to the tire radial direction in a cross-sectional view in the tire width direction. tire. Inside the rib-like land portion, the third linear opening extends across the one side and the other side in the tire width direction with respect to the cavity on the surface of the rib-like land portion. The tire according to any one of claims 1 to 3, wherein a third slit portion extending to the cavity portion is defined. The first slit portion and the second slit portion are in communication with each other over the entire area of the first slit portion and the second slit portion in the tire radial direction by the third slit portion. Tires listed. A plurality of the first slit portions and the second slit portions are arranged at predetermined intervals in the tire circumferential direction,
The first slit portion and the second slit portion are arranged in a staggered manner along the tire circumferential direction on both sides of the tire width direction sandwiching the cavity portion,
The third slit portion is located at one end of the first slit portion located on one side of the tire circumferential direction and of the second slit portion located on the other side of the tire circumferential direction. The tire according to claim 5, wherein the tire is connected to the other end closest to the one end. At least one of the first slit portion, the second slit portion, and the third slit portion has a slit width wider than an adjacent position in the slit extending direction on the surface of the rib-like land portion. The tire according to any one of claims 4 to 6, wherein a wide portion is formed.

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