JP2021091377A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire comprising land parts having improved grounding properties during progress of abrasion.SOLUTION: A pneumatic tire comprises, on a step face of a tread, partitioned block-like land parts 5. The block-like land parts 5 have a plurality of slit-like sipings 6 extending in a tire width direction and opening to the step face of the tread and pin-like sipings 7 extending respectively from bottom parts of the slit-like sipings 6 toward inside in a tire radial direction. The plurality of slit-like sipings 6 has end-side slit-like sipings 61 and 64 arranged closest to end parts 5a and 5b in a tire circumferential direction of the block-like land parts 5, and center-side slit-like sipings 62 and 63 arranged adjacent to center-sides in the tire circumferential direction of the end-side slit-like sipings 61 ad 64. Total volumes of the pin-like sipings 7 provided in the center-side slit-like sipings 62 and 63 are larger than total volumes of the pin-like sipings 7 provided in the end-side slit-like sipings 61 and 64.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pneumatic tire.

Conventionally, there is known a pneumatic tire in which a plurality of slit-shaped sipes extending in the tire width direction are provided on a block-shaped land portion formed in a section on a tread tread (see, for example, Patent Document 1). According to such a configuration, the grip performance of the pneumatic tire on a wet road surface can be improved by the edge component of the land portion formed by the slit-shaped sipe.

Japanese Unexamined Patent Publication No. 2001-71712

However, in the above-mentioned pneumatic tire, when the tread tread surface is worn due to use, the compression rigidity of the block-shaped land portion may be increased and the ground contact property may be deteriorated. In particular, there is a problem that the ground contact property of the central portion in the tire circumferential direction of the block-shaped land portion tends to decrease during normal running during wear progress.

Therefore, it is an object of the present invention to provide a pneumatic tire having improved ground contact on land during wear progress.

In one aspect, the pneumatic tire of the present invention is a pneumatic tire having a block-shaped land portion partitioned on a tread tread.
The block-shaped land portion extends in the tire width direction, and has a plurality of slit-shaped sipes that open to the tread tread and a pin-shaped portion that extends inward in the tire radial direction from the bottom of each of the slit-shaped sipes. With a sipe,
The plurality of slit-shaped sipe includes an end-side slit-shaped sipe closest to the tire circumferential end of the block-shaped land portion and a central-side slit-shaped sipe adjacent to the tire circumferential center side of the end-side slit-shaped sipe. And have
The total volume of the pin-shaped sipe provided on the central slit-shaped sipe is larger than the total volume of the pin-shaped sipe provided on the end-side slit-shaped sipe.
According to such a configuration, it is possible to reduce the compressive rigidity of the central portion of the block-shaped land portion in the tire circumferential direction during wear progress, so that the ground contact property of the block-shaped land portion during normal running during wear progress can be improved. Can be done.

Here, the "tread tread" is the entire tire circumferential direction of the tread surface that comes into contact with the road surface when a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and the maximum load is applied. It refers to the aspect that extends. The "slit-shaped sipe" refers to a notch (slit) having an opening width of less than 2 mm on the tread tread when a pneumatic tire is attached to the applicable rim, the specified internal pressure is filled, and no load is applied. Further, the "pin-shaped sipe" means a hole having a depth (length in the tire radial direction) larger than the diameter (maximum diameter) in the tread tread view (plan view). Further, "extending in the tire width direction" includes not only the case where the tire extends parallel to the tire width direction but also the case where the tire extends diagonally with respect to the tire width direction. ..

In addition, in this specification, "applicable rim" is an industrial standard that is effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (ETRTO) The European Tire and Rim Technical Organization's STANDARDS MANUAL, and in the United States, TRA (The Tire and Rim Association, Inc.)' s YEAR BOOK, etc., or the size described or applied in the future. STANDARDS MANUAL refers to the Tirering Rim, TRA's YEAR BOOK refers to the Design Rim) (ie, the "rim" above includes sizes that may be included in the industry standards in the future in addition to the current size. As an example of "the size described", the size described as "FUTURE DEVELOPMENTS" in the ETRTO 2013 edition can be mentioned.) However, if the size is not described in the above industrial standard, the bead width of the tire is used. A rim with a width corresponding to. In addition, the "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 / ply rating described in the above JATMA, etc., and is of a size not described in the above industrial standard. In this case, the "specified internal pressure" shall mean the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tires are mounted. Further, the "maximum load" means a load corresponding to the above maximum load capacity.

As the pneumatic tire, it is preferable that the central slit-shaped sipe is provided with a plurality of pin-shaped sipe.
According to such a configuration, the compressive rigidity of the block-shaped land portion on the central portion side in the tire circumferential direction can be reduced in a well-balanced manner as compared with the case where only one pin-shaped sipe is provided on the central slit-shaped sipe.

As the pneumatic tire, it is preferable that the number of pin-shaped sipe provided on the central slit-shaped sipe is larger than the number of pin-shaped sipe provided on the end-side slit-shaped sipe.
According to such a configuration, the total volume of the pin-shaped sipe provided on the central slit-shaped sipe can be changed to the end-side slit-shaped sipe without increasing the volume of the pin-shaped sipe provided on the central slit-shaped sipe. It can be larger than the total volume of the provided pin-shaped sipe.

In the pneumatic tire, the central slit-shaped sipe is located within 25% of the tire circumferential length of the block-shaped land portion from the center line of the block-shaped land portion in the tire circumferential direction. Is preferable.
According to such a configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion in the range where the ground contact property during normal running is likely to decrease when wear progresses, so that the block-shaped land portion during normal running can be more effectively reduced. It is possible to improve the ground contact property of the land area.

As the pneumatic tire, it is preferable that the central slit-shaped sipe has a branch portion between the opening opening in the tread tread and the bottom portion.
According to such a configuration, the number of slit-shaped sipe can be increased in the process of progress of wear, the pin-shaped sipe can be easily arranged in a wide range, and the number of pin-shaped sipe can be easily increased.

In another aspect, the pneumatic tire of the present invention is a pneumatic tire having a block-shaped land portion partitioned on a tread tread.
The block-shaped land portion has a plurality of lateral grooves extending in the tire width direction and opening in the tread tread surface, and a pin-shaped sipe extending inward in the tire radial direction from the bottom of each of the lateral grooves. Have and
The plurality of lateral grooves have an end side lateral groove closest to the tire circumferential end portion of the block-shaped land portion and a central side lateral groove adjacent to the tire circumferential central side of the end side lateral groove.
The total volume of the pin-shaped sipe provided in the central lateral groove is larger than the total volume of the pin-shaped sipe provided in the end lateral groove.
According to such a configuration, it is possible to reduce the compressive rigidity of the central portion of the block-shaped land portion in the tire circumferential direction during wear progress, so that the ground contact property of the block-shaped land portion during normal running during wear progress can be improved. Can be done.

As the pneumatic tire, it is preferable that a plurality of pin-shaped sipes are provided in the central lateral groove.
According to such a configuration, the compressive rigidity of the central portion in the tire circumferential direction of the block-shaped land portion can be reduced in a well-balanced manner as compared with the case where only one pin-shaped sipe is provided in the central lateral groove.

In the pneumatic tire, it is preferable that the number of pin-shaped sipes provided in the central lateral groove is larger than the number of pin-shaped sipes provided in the end lateral groove.
According to such a configuration, the total volume of the pin-shaped sipe provided in the central lateral groove is changed to the total volume of the pin-shaped sipe provided in the central lateral groove without increasing the volume of the pin-shaped sipe provided in the central lateral groove. Can be larger than the total volume of.

In the pneumatic tire, it is preferable that the central lateral groove is located within 25% of the tire circumferential length of the block-shaped land portion from the center line of the block-shaped land portion in the tire circumferential direction. ..
According to such a configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion in a range in which the ground contact property during normal running tends to decrease during normal running, so that normal running during normal running can be performed more effectively. It is possible to improve the ground contact property of the block-shaped land part at the time.

In the pneumatic tire, it is preferable that the central lateral groove has a branch portion between the opening opened in the tread tread and the bottom portion.
According to such a configuration, the number of lateral grooves can be increased in the process of progress of wear, the pin-shaped sipes can be easily arranged in a wide range, and the number of pin-shaped sipes can be easily increased.

According to the present invention, it is possible to provide a pneumatic tire having improved ground contact on land when wear progresses.

It is a development view which shows typically the tread pattern of the pneumatic tire which concerns on one Embodiment of this invention. It is a perspective view which shows the block-shaped land part alone in the pneumatic tire of FIG. It is a tire circumferential cross-sectional view which shows the deformation example of the land part of FIG. It is a development view which shows typically the tread pattern of the pneumatic tire which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Here, the internal structure and the like of the pneumatic tire (hereinafter, also simply referred to as a tire) can be the same as that of the conventional one. As an example, the tire may have a pair of bead portions, a pair of sidewall portions connected to the pair of bead portions, and a tread portion arranged between the pair of sidewall portions. .. Further, the tire may have a carcass straddling the pair of bead portions in a toroidal manner, and a belt arranged on the outer side of the crown portion of the carcass in the tire radial direction.
Hereinafter, unless otherwise specified, the dimensions and the like refer to the dimensions and the like when the tire is mounted on the applicable rim, the specified internal pressure is filled, and the load is not applied.

FIG. 1 is a development view schematically showing a tread pattern of a pneumatic tire according to an embodiment of the present invention.

As shown in FIG. 1, the tire of this example has a plurality of (4 in the illustrated example) circumferential grooves 2 (2a, 2b, 2c, 2d) extending in the tire circumferential direction on the tread tread 1. It has a plurality of widthwise grooves 3 extending in the tire width direction. Further, the tread tread 1 has a plurality of rib-shaped land portions 4 (4a, 4b, 4c) partitioned by a circumferential groove 2, a tread end TE, a width groove 3, and the like (three in the illustrated example). A plurality of block-shaped land portions 5 are provided. In the present specification, even if the rib-shaped land portion 4 is divided in the tire circumferential direction by the slit-shaped sipe 6, if the rib-shaped land portion 4 is not completely divided by the width direction groove, the rib-shaped land portion is formed. It is supposed to be included. Here, the "circumferential groove" is the opening width of the tread tread 1 in a state where the tire extends in the circumferential direction, the pneumatic tire is attached to the applicable rim, the specified internal pressure is filled, and no load is applied. However, it means a groove of 2 mm or more. Further, the "width direction groove" is the opening width of the tread tread 1 in a state where the tire extends in the tire width direction, the pneumatic tire is attached to the applicable rim, the specified internal pressure is filled, and no load is applied. 2 mm or more. The "tread end" refers to the outermost points on both sides of the tread tread 1 in the tire width direction.

In this example, the circumferential grooves 2a and 2b are located in one half of the tire width direction with the tire equatorial plane CL as the boundary, and the other circumferential grooves 2c and 2d are bordered by the tire equatorial plane CL. It is located in the other half of the tire width direction. In this example, one rib-shaped land portion 4b is arranged on the tire equatorial plane CL, and one rib-shaped land portion 4a and 4c are arranged on each tire width direction half portion. In the example shown in FIG. 1, the number of circumferential grooves 2 is 4, but it can be 1 to 3 or 5 or more. Therefore, the number of rib-shaped land portions 4 can also be one, two, or four or more. The rib-shaped land portion 4 may be a block-shaped land portion. Further, the number of block-shaped land portions 5 can be changed as appropriate. Further, the plurality of block-shaped land portions 5 may all have the same shape or may have different shapes from each other. Further, one of the two land rows provided at both ends in the tire width direction (TE side of the tread end) and composed of a plurality of block-shaped land portions 5 arranged in the circumferential direction is a rib-shaped land portion. There may be.

Further, the tread pattern provided on the tread tread surface 1 may be symmetrical or asymmetrical with respect to the tire equatorial plane CL. Further, the tread pattern may have a point-symmetrical shape with respect to one point on the tire equatorial plane CL, or may be asymmetrical.

Here, the groove width of the circumferential groove 2 (the opening width measured perpendicular to the extending direction of the groove in the tread tread view) can be, for example, 2 mm or more and 30 mm or less, and in particular, 5 mm or more. , 15 mm or less is preferable. The groove depth (maximum depth) of the circumferential groove 2 is not particularly limited, but may be, for example, 4 mm or more and 20 mm or less.

In this example, in the tread tread view shown in FIG. 1, all the circumferential grooves 2 extend along the tire circumferential direction (without tilting), but for example, at least one of the circumferential grooves 2 One may be inclined and extended with respect to the tire circumferential direction. Further, in the illustrated example, all of the circumferential grooves 2 extend linearly along the tire circumferential direction, but for example, at least one of the circumferential grooves 2 is bent in a zigzag shape or meanders. It may be curved so as to do so.

Further, the groove width of the groove 3 in the width direction (the opening width measured perpendicular to the extending direction of the groove in the tread tread view) is not particularly limited, but can be, for example, 2 mm or more and 20 mm or less. In particular, it is preferably 2 mm or more and 15 mm or less. The groove depth (maximum depth) of the width direction groove 3 is not particularly limited, but may be, for example, 2 mm or more and 20 mm or less.

In this example, in the tread tread view shown in FIG. 1, the width direction grooves 3 extend along the tire width direction (without tilting), but for example, at least one of the width direction grooves 3 One may be inclined and extended with respect to the tire width direction. Further, in the illustrated example, all of the width direction grooves 3 extend linearly along the tire width direction, but for example, at least one of the width direction grooves 3 is bent in a zigzag shape or meanders. It may be curved so as to do so.

The ribbed land portion 4 is partitioned by two circumferential grooves 2 adjacent to each other in the tire width direction, or is partitioned by the circumferential groove 2 and the tread end TE. The three ribbed land portions 4 (4a, 4b, 4c) of this example are all partitioned by circumferential grooves 2 (2a, 2b, 2c, 2d).

In this example, a plurality of block-shaped land portions 5 are provided side by side in the circumferential direction on both sides of the three rib-shaped land portions 4 in the tire width direction. The block-shaped land portion 5 of this example is partitioned by circumferential grooves 2a and 2d, a tread end TE, and a width groove 3. The shape of the block-shaped land portion 5 can be changed according to the shapes of the circumferential groove 2 and the width direction groove 3.

Here, FIG. 2 is an enlarged perspective view showing one block-shaped land portion 5. In this example, the block-shaped land portion 5 includes a plurality of slit-shaped sipes 6 (61, 62, 63, 64) extending in the tire width direction (four in the illustrated example) and each slit-shaped sipe 6. A pin-shaped sipe 7 extending inward in the radial direction from the bottom portion 6a is provided. The plurality of slit-shaped sipes 6 are arranged at intervals in the tire circumferential direction. The distance between the two slit-shaped sipes 6 adjacent to each other in the tire circumferential direction (distance in the tire circumferential direction) is not particularly limited.

The plurality of slit-shaped sipes 6 (61, 62, 63, 64) are the end-side slit-shaped sipes 61, 64 closest to the tire circumferential end portions 5a and 5b of the block-shaped land portion 5, and the end-side slit-shaped sipes. The total volume of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 having the central slit-shaped sipes 62 and 63 adjacent to the center side in the tire circumferential direction of 61 and 64 is the end-side slit-shaped sipes 62 and 63. It is configured to be larger than the total volume of the pin-shaped sipe 7 provided on the sipe 61 and 64.

In this example, one block-shaped land portion 5 is provided with two end-side slit-shaped sipes 61 and 64 and two central-side slit-shaped sipes 62 and 63. More specifically, the block-shaped land portion 5 shown in FIGS. 1 and 2 includes an end-side slit-shaped sipe 61 closest to one tire circumferential end portion 5a of the block-shaped land portion 5 and an end-side slit-shaped sipe 61. It has a central slit-shaped sipe 62 adjacent to the central side in the tire circumferential direction. Further, the block-shaped land portion 5 has an end-side slit-shaped sipe 64 closest to the other tire circumferential end 5b of the block-shaped land portion 5 and a center adjacent to the tire circumferential center side of the end-side slit-shaped sipe 64. It has a side slit-shaped sipe 63.

One pin-shaped sipe 7 is provided on the bottom 6a of the end-side slit-shaped sipe 61, and two pin-shaped sipe 7 are spaced apart from each other on the bottom 6a of the center-side slit-shaped sipe 62. It is provided. In this example, the total volume of the two pin-shaped sipes 7 provided on the central slit-shaped sipe 62 is larger than the total volume of one pin-shaped sipe 7 provided on the end-side slit-shaped sipe 61. ing.

Further, the two pin-shaped sipes 7 of the central slit-shaped sipe 62 are symmetrically arranged with the center line in the tire width direction of the block-shaped land portion 5 interposed therebetween, and the pin-shaped sipes 7 of the end-side slit-shaped sipe 61 are arranged symmetrically. Is arranged at the center of the block-shaped land portion 5 in the tire width direction. As described above, the two pin-shaped sipes 7 of the central slit-shaped sipe 62 and the one pin-shaped sipe 7 of the end-side slit-shaped sipe 61 are located at positions displaced in the tire width direction in the block-shaped land portion 5. Is located in.

Further, two pin-shaped sipes 7 are provided on the bottom 6a of the central slit-shaped sipe 63 at intervals from each other, and one pin-shaped sipe 7 is provided on the bottom 6a of the end-side slit-shaped sipe 64. A sipe 7 is provided. The two pin-shaped sipes 7 of the central slit-shaped sipe 63 are symmetrically arranged with the center line in the tire width direction of the block-shaped land portion 5 interposed therebetween, and the pin-shaped sipes 7 of the end-side slit-shaped sipes 64 are arranged symmetrically. It is arranged at the center of the block-shaped land portion 5 in the tire width direction. In this way, the two pin-shaped sipe 7 of the central slit-shaped sipe 63 and the pin-shaped sipe 7 of the end-side slit-shaped sipe 64 are arranged at positions shifted in the tire width direction in the block-shaped land portion 5. ing.

In this example, the slit-shaped sipes 61, 62, 63, 64 and the pin-shaped sipes 7 are arranged so as to be symmetrical with respect to the center line 5c in the tire circumferential direction of the block-shaped land portion 5.

Here, in this example, the number of pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 is larger than the number of pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64. By doing so, the total volume of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 is made larger than the total volume of the pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64. However, it is not limited to this. For example, by making the pin-shaped sipe 7 provided on the central slit-shaped sipe 62, 63 larger than the pin-shaped sipe 7 provided on the end-side slit-shaped sipe 61, 64, the central slit-shaped sipe 62, The total volume of the pin-shaped sipe 7 provided on the 63 may be made larger than the total volume of the pin-shaped sipe 7 provided on the end-side slit-shaped sipe 61 and 64. In that case, the number of pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64 and the number of pin-shaped sipes 7 provided on the central-side slit-shaped sipes 62 and 63 may be the same or different. May be good.

The tread tread 1 may be provided with at least one block-shaped land portion 5 having the end-side slit-shaped sipe 61, 64 and the center-side slit-shaped sipe 62, 63 as described above. Further, the block-shaped land portion 5 may be provided with at least one end-side slit-shaped sipe 61, 64 and a central-side slit-shaped sipe 62, 63. In this example, in all the block-shaped land portions 5 provided on the tread tread 1, the total volume of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 becomes the end-side slit-shaped sipes 61 and 64. It is configured to be larger than the total volume of the provided pin-shaped sipe 7.

The tread tread 1 may have a slit-shaped sipe 6 and a block-shaped land portion 5 having no pin-shaped sipe 7, and all the block-shaped land portions 5 have a slit-shaped sipe 6 and a pin-shaped sipe 7. May have. Further, the configuration of the rib-shaped land portion 4 (4a, 4b, 4c) is not particularly limited, and a slit-shaped sipe and / or a pin-shaped sipe may or may not be provided.

The slit-shaped sipes 6 shown in FIGS. 1 and 2 extend in a straight line along the tire width direction (parallel to the tire width direction). The slit-shaped sipe 6 extends over the entire width direction of the block-shaped land portion 5. That is, one end of the slit-shaped sipe 6 in the extending direction is located at the tread end TE, and the other end communicates with the circumferential groove 2a. The slit-shaped sipe 6 may be inclined and extend diagonally with respect to the tire width direction. Further, either one end or both ends of the slit-shaped sipe 6 in the extending direction may be terminated within the block-shaped land portion 5. Further, the slit-shaped sipe 6 is not limited to a shape in which the entire shape is linear along the extending direction in the tread tread view shown in FIG. 1, and may have a curved portion or a bent portion.

The sipe width of the slit-shaped sipe 6 (the opening width measured perpendicular to the extending direction of the slit-shaped sipe 6 on the tread tread 1) can be, for example, 0.2 mm or more and 1.0 mm or less, particularly. , 0.3 mm or more, preferably 0.7 mm or less. The sipe width of the slit-shaped sipe 6 is preferably constant along the extending direction of the slit-shaped sipe 6 as in this example, but the sipe width may change along the extending direction. Further, the slit-shaped sipe 6 preferably extends in a straight line in the tire radial direction (depth direction of the slit-shaped sipe 6) from the opening 6b opening in the tread tread 1 to the bottom 6a. The slit-shaped sipe 6 may be inclined with respect to the tire radial direction, and may have a curved portion or a bent portion. Further, the sipe width of the slit-shaped sipe 6 is preferably constant along the depth direction of the slit-shaped sipe 6, but the sipe width may change along the depth direction. Further, the sipe depth of the slit-shaped sipe 6 (the length in the tire radial direction from the opening 6b to the tread tread 1 to the bottom 6a) can be, for example, 1 mm or more and 20 mm or less, and in particular, 3 mm or more. , 15 mm or less is preferable.

The pin-shaped sipe 7 is not exposed on the tread tread 1 when it is new, but is exposed when the tread tread 1 is worn to a predetermined position (bottom 6a of the slit-shaped sipe 6) due to the use of a tire. It is configured. The pin-shaped sipe 7 of this example is a columnar space (hole) extending in a straight line from the bottom 6a of the slit-shaped sipe 6 toward the inside in the tire radial direction.

The shape, volume (volume), position, and number of the pin-shaped sipes 7 can be changed as appropriate. For example, three or more pin-shaped sipes 7 may be provided on the bottom portion 6a of one slit-shaped sipes 6. Further, the block-shaped land portion 5 may have a slit-shaped sipe 6 in which the pin-shaped sipe 7 is not provided. Further, the shape of the pin-shaped sipe 7 is not limited to the columnar shape as in this example, and may be, for example, a polygonal columnar shape. It may have a Y-shape, an X-shape, or the like.

In the pin-shaped sipe 7 of this example, the shape of the cross section (the cross section perpendicular to the extending direction (depth direction) of the pin-shaped sipe 7) is constant from the upper end to the lower end of the pin-shaped sipe 7. The shape is not limited, and the cross-sectional shape may change along the depth direction. For example, the pin-shaped sipe 7 may have a shape in which the diameter gradually increases (continuously or stepwise) from the upper end to the lower end, or conversely, from the upper end to the lower end of the pin-shaped sipe 7. , The shape may be gradually reduced in diameter.

The sipe diameter (maximum diameter in tread tread view) of the pin-shaped sipe 7 can be, for example, 0.2 mm or more and 5.0 mm or less, and in particular, 0.3 mm or more and 2.0 mm or less. preferable. Further, the sipe diameter of the pin-shaped sipe 7 is preferably equal to or less than the sipe width of the slit-shaped sipe 6 in terms of facilitating the formation of the pin-shaped sipe 7. In the examples shown in FIGS. 1 and 2, the diameter of the pin-shaped sipe 7 is larger than the sipe width of the slit-shaped sipe 6.

The sipe depth of the pin-shaped sipe 7 (the length in the tire radial direction from the upper end to the lower end of the pin-shaped sipe 7) can be, for example, 0.5 mm or more and 15 mm or less, particularly 1.0 mm or more. It is preferably 5.0 mm or less.

As described above, the tire of the present embodiment is a pneumatic tire provided with the block-shaped land portion 5 partitioned on the tread tread surface 1, and the block-shaped land portion 5 extends in the tire width direction and the tread tread surface 1 The plurality of slit-shaped sipes 6 have a plurality of slit-shaped sipes 6 opening to the tire and a pin-shaped sipes 7 extending inward in the tire radial direction from the bottom 6a of each of the slit-shaped sipes 6. , End-side slit-shaped sipe 61, 64 closest to the tire circumferential end 5a, 5b of the block-shaped land portion 5, and center-side slit-shaped sipe adjacent to the tire circumferential center side of the end-side slit-shaped sipe 61, 64. 62, 63, and the total volume of the pin-shaped sipe 7 provided on the central slit-shaped sipe 62, 63 is larger than the total volume of the pin-shaped sipe 7 provided on the end-side slit-shaped sipe 61, 64. It is characterized by being large. According to such a configuration, by providing the pin-shaped sipe 7, the compressive rigidity of the block-shaped land portion 5 at the time of wear progress is reduced, and the tread tread 1 can easily bite into the road surface. For example, when a slit-shaped sipe extending to the depth of the lower end of the pin-shaped sipe 7 is provided instead of the pin-shaped sipe 7, the depth of the slit-shaped sipe 6 is increased to the depth of the lower end of the pin-shaped sipe 7. In the case), there is a possibility that the land portion may collapse. However, in the present embodiment, by providing the pin-shaped sipe 7 while maintaining the slit-shaped sipe 6 at an appropriate depth, such a collapse of the land portion occurs. Can be suppressed. As a result, the ground contact property of the block-shaped land portion 5 at the time of wear progress can be appropriately improved. Further, since the total volume of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 is larger than the total volume of the pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64, the block-shaped land The compressive rigidity of the central portion in the tire circumferential direction of the portion 5 is lower than the compressive rigidity of the end portions 5a and 5b in the tire circumferential direction, and the ground contact property of the block-shaped land portion 5 during normal traveling can be improved. As a result, it is possible to improve the ground contact property of the block-shaped land portion 5 during normal traveling during wear progress, and for example, it is possible to improve the grip performance on a wet road surface during wear progress.

In the tire of the present embodiment, since the pin-shaped sipe 7 connected to the bottom 6a of the slit-shaped sipe 6 is provided, the road surface and the tread tread 1 are as compared with the case where the pin-shaped sipe 7 is not provided. Since the water between the tires can be sucked up to the pin-shaped sipe 7 via the slit-shaped sipe 6, it is possible to improve the drainage property of the tire.

Further, in the tire of the present embodiment, since the slit-shaped sipe 6 extends in the tire width direction, the edge component in the tire width direction (edge with respect to the tire circumferential direction) until the pin-shaped sipe 7 is exposed. The component) can be increased to improve the grip performance of the tire on a wet road surface until the wear progresses when the pin-shaped sipe 7 is exposed.

Here, in the tire of the present embodiment, it is preferable that the slit-shaped sipe 6 extends parallel to the tire width direction. With such a configuration, the edge component in the tire width direction until the pin-shaped sipe 7 is exposed is increased, and the grip performance of the tire on a wet road surface until the pin-shaped sipe 7 is exposed and the wear progresses is improved. Can be improved.

The slit-shaped sipe 6 may be inclined and extended in the tire width direction. In this case, the slit-shaped sipe 6 is inclined and extended at an inclination angle of 45 ° or less with respect to the tire width direction. It is preferable that the tire extends at an inclination angle of 30 ° or less. Further, it is preferable that the slit-shaped sipe 6 extends in a straight line along the tire width direction in the tread tread view. On the other hand, the slit-shaped sipe 6 is not limited to a linear shape along the extending direction, and may have a curved portion or a bent portion.

Further, in the tire of the present embodiment, a plurality of pin-shaped sipes 7 are provided on the central slit-shaped sipes 62 and 63. According to this configuration, the compressive rigidity of the block-shaped land portion 5 on the center side in the tire circumferential direction can be reduced in a well-balanced manner as compared with the case where only one pin-shaped sipe 7 is provided on the central slit-shaped sipe 62 and 63. it can.

Further, in the tire of the present embodiment, the number of pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 is the number of pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64. Is more than According to such a configuration, the total of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63 without increasing the volume of the pin-shaped sipes 7 provided on the central slit-shaped sipes 62 and 63. The volume can be made larger than the total volume of the pin-shaped sipes 7 provided on the end-side slit-shaped sipes 61 and 64.

Further, in the tire of the present embodiment, the central slit-shaped sipes 62 and 63 are 25% of the tire circumferential length of the block-shaped land portion 5 from the center line 5c of the block-shaped land portion 5 in the tire circumferential direction. Located within the range. According to such a configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion 5 in a range in which the ground contact property during normal running is likely to decrease during wear progress, and thus it is possible to more effectively reduce the compressive rigidity during normal travel during wear progress. It is possible to improve the ground contact property of the block-shaped land portion 5 during traveling.

Here, FIG. 3 shows an example in which the slit-shaped sipe 6 has a branch portion 6c between the opening 6b and the bottom 6a that opens in the tread tread 1. Note that FIG. 3 shows a cross section of the slit-shaped sipe 6 perpendicular to the extending direction. That is, FIG. 3 shows a cross section in the tire circumferential direction when the slit-shaped sipe 6 extends in the tire width direction, for example, as shown in FIG. The type of the slit-shaped sipe 6 having the branch portion 6c is not particularly limited. That is, for example, in the block-shaped land portion 5 shown in FIGS. 1 and 2, all four slit-shaped sipes 61, 62, 63, and 64 may have a branch portion 6c, or any one to three. Only the slit-shaped sipe 6 (61, 62, 63, 64) of the above may have a branch portion 6c.

As shown in FIG. 3, the slit-shaped sipe 6 includes a tread-side sipe portion 6d extending inward in the tire radial direction from an opening 6b opening in the tread tread surface 1 and a branch portion 6c from the tread-side sipe portion 6d. It has a branch sipe portion 6e, which branches and extends through the tread.

The tread side sipe portion 6d extends in the normal direction (tire radial direction) of the tread tread 1, and the branch sipe portion 6e extends horizontally along the tire circumferential direction in the tire circumferential cross-sectional view of FIG. It consists of a sipe portion 6f and two vertical sipe portions 6g extending in the normal direction of the tread tread 1. A pin-shaped sipe 7 is provided on the bottom 6a of each of the two vertical sipe portions 6g. According to such a configuration, since one slit-shaped sipe 6 branches into two in the wear progressing process, the number of slit-shaped sipe 6 can be increased in the wear progressing process. Further, since the number of bottoms 6a is larger than the opening 6b of the slit-shaped sipe 6 opening in the tread tread 1 and the position of the bottom 6a is widened, it is easy to arrange the pin-shaped sipe 7 in a wide range. It becomes easy to increase the number of pin-shaped sipe 7. As a result, the edge component can be increased by increasing the number of slit-shaped sipes 6 in the wear progressing process, and the effect of improving the ground contact property at the time of wear progressing by arranging a large number of pin-shaped sipes 7 in a wide range is effective. Can be enhanced. Further, from the viewpoint of improving the ground contact property during normal running during wear progress, it is preferable that the branch portions 6c are provided on the central slit-shaped sipes 62 and 63.

The slit-shaped sipe 6 and the pin-shaped sipe 7 can be manufactured, for example, by processing a metal plate, casting, laminated molding (3D printer), or the like, but the present invention is not limited thereto.

The present invention can be similarly applied not only to the slit-shaped sipe 6 as described above, but also to the lateral groove 8 having a groove width larger than that of the slit-shaped sipe 6. In that case, the pneumatic tire includes, for example, a block-shaped land portion 5 partitioned on the tread tread surface 1, and the block-shaped land portion 5 extends in the tire width direction to the tread tread surface 1. It has a plurality of lateral grooves 8 to be opened and a pin-shaped sipe 7 extending inward in the tire radial direction from the bottom of each lateral groove 8, and the plurality of lateral grooves 8 are tires of the block-shaped land portion 5. It has end side lateral grooves 81 and 84 closest to the circumferential end portions 5a and 5b, and central side lateral grooves 82 and 83 adjacent to the tire circumferential central side of the end side lateral grooves 81 and 84, and has central side lateral grooves 82 and 83. The total volume of the pin-shaped sipe 7 provided in the tire is larger than the total volume of the pin-shaped sipe 7 provided in the end side lateral grooves 81 and 84. Here, the lateral groove 8 extends in the tire width direction, and a groove having an opening width of 2 mm or more in the tread tread 1 in a state where a pneumatic tire is attached to the applicable rim, a specified internal pressure is applied, and no load is applied. Say.

The pneumatic tire can also improve the ground contact property of the block-shaped land portion 5 during normal running during normal running for the same reason as described in the case of the slit-shaped sipe 6.

In this case, it is preferable that the central lateral grooves 82 and 83 are provided with a plurality of pin-shaped sipes 7. According to such a configuration, the compressive rigidity of the block-shaped land portion 5 on the central side in the tire circumferential direction can be reduced in a well-balanced manner as compared with the case where only one pin-shaped sipe 7 is provided in the central lateral grooves 82 and 83.

As for the above-mentioned pneumatic tire, it is preferable that the number of pin-shaped sipes 7 provided in the central lateral grooves 82 and 83 is larger than the number of pin-shaped sipes 7 provided in the end side lateral grooves 81 and 84. According to such a configuration, the total volume of the pin-shaped sipes 7 provided in the central lateral grooves 82 and 83 is set to the end side without increasing the volume of the pin-shaped sipes 7 provided in the central lateral grooves 82 and 83. It can be made larger than the total volume of the pin-shaped sipes 7 provided in the lateral grooves 81 and 84.

In the above-mentioned pneumatic tire, the central lateral grooves 82 and 83 are located within a range of 25% or less of the tire circumferential length of the block-shaped land portion 5 from the tire circumferential center line 5c of the block-shaped land portion 5. Is preferable. According to such a configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion 5 in a range in which the ground contact property during normal running tends to decrease when wear progresses, so that the block during normal running can be more effectively reduced. The ground contact property of the land portion 5 can be improved.

As the above-mentioned pneumatic tire, it is preferable that the central lateral grooves 82 and 83 have a branch portion between the opening opened in the tread tread 1 and the bottom portion. According to such a configuration, the number of lateral grooves 8 can be increased in the process of progress of wear, the pin-shaped sipes 7 can be easily arranged in a wide range, and the number of pin-shaped sipes 7 can be easily increased. As a result, the edge component due to the lateral groove 8 can be increased, and the effect of improving the ground contact property at the time of wear progress by the pin-shaped sipe 7 can be enhanced.

The lateral groove 8 preferably extends parallel to the tire width direction. With such a configuration, in the wear progress process until the pin-shaped sipe 7 is exposed to the tread tread 1, the edge component in the tire width direction is increased until the pin-shaped sipe 7 is exposed. It is possible to improve the grip performance of the tire on a wet road surface.

The lateral groove 8 of this example extends in a straight line along the tire width direction (parallel to the tire width direction). The lateral groove 8 extends to a part of the block-shaped land portion 5 in the width direction. That is, both ends of the lateral groove 8 in the extending direction are terminated in the block-shaped land portion 5. The lateral groove 8 may be inclined with respect to the tire width direction and extend diagonally. Further, one end of the lateral groove 8 in the extending direction may communicate with the circumferential groove 2 (2b, 2c). Further, the lateral groove 8 is not limited to a linear shape along the extending direction, and may have a curved portion or a bent portion.

The groove width of the lateral groove 8 (the opening width measured perpendicular to the extending direction of the lateral groove 8 on the tread tread 1) can be, for example, 2 mm or more and 10 mm or less. The groove width of the lateral groove 8 is preferably constant along the extending direction of the lateral groove 8 as in this example, but the groove width may change along the extending direction. Further, the groove width of the lateral groove 8 is preferably constant along the depth direction of the lateral groove 8, but the groove width may change along the depth direction. Further, the groove depth of the lateral groove 8 (the length in the tire radial direction from the opening to the tread tread 1 to the bottom) can be, for example, 2 mm or more and 20 mm or less.

The pneumatic tire according to the present invention is not limited to the specific configurations shown in the above-described embodiments and modifications, and can be variously modified and modified without departing from the scope of claims.

1: Tread tread 2 (2a, 2b, 2c, 2d): Circumferential groove 3: Width groove 4 (4a, 4b, 4c): Rib-shaped land part 5: Block-shaped land part 5a, 5b: Block-shaped land part Tire circumferential end 6: Slit-shaped sipe 6a: Bottom 6b: Opening 6c: Branch 6d: Tread side sipe 6e: Branch sipe 6f: Horizontal sipe 6g: Vertical sipe 7: Pin-shaped sipe 8: Horizontal groove 61, 64: End side slit-shaped sipe 62, 63: Central side slit-shaped sipe 81, 84: End side lateral groove 82, 83: Central side horizontal groove

Claims (10)

A pneumatic tire with a block-shaped land section partitioned on the tread tread.
The block-shaped land portion extends in the tire width direction, and has a plurality of slit-shaped sipes that open to the tread tread and a pin-shaped portion that extends inward in the tire radial direction from the bottom of each of the slit-shaped sipes. With a sipe,
The plurality of slit-shaped sipe includes an end-side slit-shaped sipe closest to the tire circumferential end of the block-shaped land portion and a central-side slit-shaped sipe adjacent to the tire circumferential center side of the end-side slit-shaped sipe. And have
A pneumatic tire, wherein the total volume of the pin-shaped sipe provided on the central slit-shaped sipe is larger than the total volume of the pin-shaped sipe provided on the end-side slit-shaped sipe. The pneumatic tire according to claim 1, wherein a plurality of the pin-shaped sipe is provided on the central slit-shaped sipe. The pneumatic tire according to claim 1 or 2, wherein the number of the pin-shaped sipe provided on the central slit-shaped sipe is larger than the number of pin-shaped sipe provided on the end-side slit-shaped sipe. Any of claims 1 to 3, wherein the central slit-shaped sipe is located within 25% of the tire circumferential length of the block-shaped land portion from the center line of the block-shaped land portion in the tire circumferential direction. Pneumatic tires described in item 1. The pneumatic tire according to any one of claims 1 to 4, wherein the central slit-shaped sipe has a branch portion between an opening opening in the tread tread and the bottom portion. A pneumatic tire with a block-shaped land section partitioned on the tread tread.
The block-shaped land portion has a plurality of lateral grooves extending in the tire width direction and opening in the tread tread surface, and a pin-shaped sipe extending inward in the tire radial direction from the bottom of each of the lateral grooves. Have and
The plurality of lateral grooves have an end side lateral groove closest to the tire circumferential end portion of the block-shaped land portion and a central side lateral groove adjacent to the tire circumferential central side of the end side lateral groove.
A pneumatic tire characterized in that the total volume of pin-shaped sipe provided in the central lateral groove is larger than the total volume of pin-shaped sipe provided in the end lateral groove. The pneumatic tire according to claim 6, wherein a plurality of the pin-shaped sipes are provided in the central lateral groove. The pneumatic tire according to claim 6 or 7, wherein the number of pin-shaped sipes provided in the central lateral groove is larger than the number of pin-shaped sipes provided in the end lateral groove. Any one of claims 6 to 8, wherein the central lateral groove is located within a range of 25% or less of the tire circumferential length of the block-shaped land portion from the center line of the block-shaped land portion in the tire circumferential direction. Pneumatic tires described in. The pneumatic tire according to any one of claims 6 to 9, wherein the central lateral groove has a branch portion between an opening opening in the tread tread and the bottom portion.

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