JP7397647B2 - pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

BACKGROUND ART Conventionally, a pneumatic tire is known in which a plurality of slit-shaped sipes extending in the width direction of the tire are provided in a block-shaped land portion defined in a tread surface (for example, see 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-like sipe.

Japanese Patent Application Publication No. 2001-71712

However, in the above-mentioned pneumatic tire, when the tread surface wear progresses due to use, the compression rigidity of the block-shaped land portion may increase and the ground contact may deteriorate. In particular, during braking when wear progresses, there is a problem in that the ground contact on the tire circumferential end side of the block-shaped land portion tends to deteriorate.

Therefore, it is an object of the present invention to provide a pneumatic tire that improves the ground contact performance of the land portion during the progress of wear.

In one aspect, the pneumatic tire of the present invention is a pneumatic tire comprising a block-shaped land portion partitioned into a tread surface, the pneumatic tire comprising:
The block-shaped land portion includes a plurality of slit-shaped sipes extending in the width direction of the tire and opening into the tread surface, and a pin-shaped portion extending inward in the tire radial direction from the bottom of each of the slit-shaped sipes. has a sipe,
The plurality of slit-like sipes include an end-side slit-like sipe closest to the end of the block-like land portion in the tire circumferential direction, and a center-side slit-like sipe adjacent to the end-side slit-like sipe on the center side in the tire circumferential direction. and has
The total volume of the pin-shaped sipes provided in the end-side slit-shaped sipes is larger than the total volume of the pin-shaped sipes provided in the center-side slit-shaped sipes.
According to this configuration, it is possible to reduce the compressive rigidity of the block-shaped land portion on the tire circumferential end side when wear progresses, thereby improving the ground contact of the block-like land portion during braking when wear progresses. I can do it.

Here, "tread surface" refers to the entire circumferential area of the tread surface that will come into contact with the road surface when a pneumatic tire is mounted on an applicable rim, filled with specified internal pressure, and the maximum load is applied. refers to the area that spans Furthermore, the term "slit-shaped sipe" refers to a cut (slit) with an opening width of less than 2 mm in the tread surface when a pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and under no load. Further, the term "pin-shaped sipe" refers to a hole whose depth (length in the tire radial direction) is larger than the diameter (maximum diameter) when viewed from the tread surface (planar view). Furthermore, "extending in the tire width direction" includes not only extending parallel to the tire width direction, but also extending obliquely to the tire width direction. .

In addition, in this specification, "applicable rim" refers to an industrial standard that is valid in the region where tires are produced and used, such as JATMA YEAR BOOK of JATMA (Japan Automobile Tire Association) in Japan, and ETRTO ( It is described in the STANDARDS MANUAL of The European Tire and Rim Technical Organization, and in the YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States. Standard rims (ETRTO (Measuring Rim in STANDARDS MANUAL, Design Rim in TRA's YEAR BOOK) (Examples of "specified sizes" include the sizes listed as "FUTURE DEVELOPMENTS" in the 2013 edition of ETRTO.) However, in the case of sizes not listed in the above industrial standards, the bead width of the tire A rim with a width corresponding to In addition, "specified internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity of a single wheel in the applicable size and ply rating, as described in the JATMA, etc., above, and for sizes not listed in the above industrial standards. In this case, "specified internal pressure" shall mean the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle to which the tire is installed. Furthermore, the term "maximum load" refers to a load corresponding to the maximum load capacity.

In the above pneumatic tire, it is preferable that the end side slit-shaped sipe is provided with a plurality of pin-shaped sipes.
According to this configuration, the compression rigidity of the block-shaped land portion at the tire circumferential end side can be reduced in a well-balanced manner compared to the case where only one pin-shaped sipe is provided in the end-side slit-shaped sipe.

In the above pneumatic tire, it is preferable that the number of pin-shaped sipes provided on the end-side slit-shaped sipes is greater than the number of pin-shaped sipes provided on the center-side slit-shaped sipes.
According to this configuration, the total volume of the pin-shaped sipes provided in the end-side slit-shaped sipe can be increased to the center-side slit-shaped sipe without increasing the individual volume of the pin-shaped sipe provided in the end-side slit-shaped sipe. The volume can be larger than the total volume of the provided pin-shaped sipes.

In the above pneumatic tire, the end-side slit-shaped sipe may be located within 25% of the tire circumferential length of the block-shaped land portion from the tire circumferential end of the block-shaped land portion. preferable.
According to this configuration, it is possible to more reliably reduce the compression rigidity of the block-shaped land portion in a range where the ground contact during braking is likely to decrease during wear progress, and therefore, the block-shaped land portion during braking can be more effectively reduced. can improve ground contact.

In the above pneumatic tire, it is preferable that the end-side slit-shaped sipe has a branch part between the opening opening in the tread surface and the bottom part.
According to such a configuration, the number of slit-shaped sipes can be increased in the course of wear progress, and the pin-shaped sipes can be easily arranged in a wide range, and the number of pin-shaped sipes can also be easily increased.

In another aspect, the pneumatic tire of the present invention is a pneumatic tire comprising a block-shaped land portion divided into a tread surface,
The block-shaped land portion includes a plurality of lateral grooves extending in the width direction of the tire and opening in the tread surface, and pin-shaped sipes extending inward in the tire radial direction from the bottom of each of the lateral grooves. have,
The plurality of lateral grooves have an end lateral groove closest to the tire circumferential end of the block-shaped land portion, and a center lateral groove adjacent to the tire circumferential center side of the end lateral groove,
The total volume of the pin-shaped sipes provided in the end-side lateral groove is larger than the total volume of the pin-shaped sipes provided in the center-side lateral groove.
According to this configuration, it is possible to reduce the compressive rigidity of the block-shaped land portion on the tire circumferential end side when wear progresses, thereby improving the ground contact of the block-like land portion during braking when wear progresses. I can do it.

In the above pneumatic tire, it is preferable that a plurality of the pin-shaped sipes are provided in the end side lateral groove.
According to this configuration, the compression rigidity of the block-shaped land portion at the tire circumferential end portion side can be reduced in a well-balanced manner compared to the case where only one pin-shaped sipe is provided in the end-side lateral groove.

In the above pneumatic tire, it is preferable that the number of pin-shaped sipes provided in the end-side lateral groove is greater than the number of pin-shaped sipes provided in the center-side lateral groove.
According to this configuration, the total volume of the pin-shaped sipes provided in the end-side lateral grooves can be increased by the total volume of the pin-shaped sipes provided in the center-side lateral grooves without increasing the individual volume of the pin-shaped sipes provided in the end-side lateral grooves. can be larger than the total volume of

In the above pneumatic tire, it is preferable that the end lateral groove is located within a range of 25% or less of the length of the block-shaped land portion in the tire circumferential direction from the end of the block-shaped land portion in the tire circumferential direction.
According to this configuration, it is possible to more reliably reduce the compression rigidity of the block-shaped land portion in a range where the ground contact during braking is likely to decrease during wear progress, and therefore, the block-shaped land portion during braking can be more effectively reduced. can improve ground contact.

In the above pneumatic tire, it is preferable that the end-side lateral groove has a branch part between the opening opening in the tread surface and the bottom part.
According to this configuration, the number of lateral grooves can be increased during the wear progress process, and the pin-shaped sipes can be easily arranged in a wide range, and the number of pin-shaped sipes can also be easily increased.

According to the present invention, it is possible to provide a pneumatic tire that improves the ground contact performance of the land portion during the progress of wear.

1 is a developed view schematically showing a tread pattern of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a perspective view showing a block-shaped land portion alone in the pneumatic tire of FIG. 1. FIG. FIG. 2 is a tire circumferential cross-sectional view showing a modification of the land portion of FIG. 1; FIG. 3 is a developed view schematically showing a tread pattern of a pneumatic tire according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be illustrated in detail with reference to the drawings.
Here, the internal structure of the pneumatic tire (hereinafter also simply referred to as a tire) can be the same as that of a conventional tire. For example, the tire may include a pair of bead portions, a pair of sidewall portions connected to the pair of bead portions, and a tread portion disposed between the pair of sidewall portions. . Further, the tire may include a carcass extending in a toroidal manner between a pair of bead portions, and a belt disposed outside the crown portion of the carcass in the tire radial direction.
Hereinafter, unless otherwise specified, dimensions refer to the dimensions when the tire is mounted on the applicable rim, filled with the specified internal pressure, and placed in an unloaded state.

FIG. 1 is a developed 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 (four in the illustrated example) circumferential grooves 2 (2a, 2b, 2c, 2d) extending in the tire circumferential direction on a tread surface 1, It has a plurality of width direction grooves 3 extending in the tire width direction. Further, the tread surface 1 includes a plurality of (three in the illustrated example) rib-like land portions 4 (4a, 4b, 4c) partitioned by the circumferential groove 2, the tread end TE, the width direction groove 3, etc. A plurality of block-shaped land portions 5 are provided. In this specification, even if the rib-like land portion 4 is divided in the tire circumferential direction by the slit-like sipe 6, if it is not completely divided by the widthwise groove, the rib-like land portion shall be included. Here, the "circumferential groove" refers to the opening width in the tread surface 1 that extends in the tire circumferential direction, and when the pneumatic tire is mounted on the applicable rim, the specified internal pressure is filled, and there is no load. refers to a groove of 2 mm or more. Furthermore, the term "width direction groove" refers to a groove that extends in the width direction of the tire and has an opening width in the tread surface 1 when the pneumatic tire is mounted on the applicable rim, filled with a specified internal pressure, and under no load. , 2mm or more. Moreover, "tread edge" refers to the outermost point of the tread surface 1 on both sides 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 a boundary, and the other circumferential grooves 2c and 2d are located in one half of the tire width direction with the tire equatorial plane CL as a boundary. It is located in the other half of the tire in the 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, 4c is arranged in each half in the tire width direction. In the example shown in FIG. 1, the number of circumferential grooves 2 is four, but it may also be one to three or five or more. Therefore, the number of rib-like land portions 4 can also be one, two, or four or more. Note that the rib-like land portion 4 may be a block-like land portion. Further, the number of block-shaped land portions 5 can also be changed as appropriate. Further, the plurality of block-shaped land portions 5 may all have the same shape, or may have mutually different shapes. Moreover, one of the two land part rows formed of a plurality of block-shaped land parts 5 arranged in the circumferential direction and provided at both ends in the tire width direction (tread end TE side) is a rib-shaped land part. It may be.

Further, the tread pattern provided on the tread surface 1 may be symmetrical or asymmetrical with respect to the tire equatorial plane CL. Further, the tread pattern may be point-symmetrical 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 perpendicularly to the extending direction of the groove when viewed from the tread surface) may be, for example, 2 mm or more and 30 mm or less, particularly 5 mm or more. , preferably 15 mm or less. Further, 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 surface view shown in FIG. 1, all of the circumferential grooves 2 extend along the tire circumferential direction (without inclination). The books may extend obliquely with respect to the tire circumferential direction. Further, in the illustrated example, all of the circumferential grooves 2 extend linearly along the circumferential direction of the tire, but for example, at least one of the circumferential grooves 2 may be bent in a zigzag shape, or It may be curved in a meandering manner.

Further, the width of the width direction groove 3 (opening width measured perpendicular to the extending direction of the groove when viewed from the tread surface) is not particularly limited, but may 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. Further, the groove depth (maximum depth) of the widthwise groove 3 is not particularly limited, but can be, for example, 2 mm or more and 20 mm or less.

In this example, when viewed from the tread surface shown in FIG. 1, all the width direction grooves 3 extend along the tire width direction (without inclination); The books may extend obliquely with respect to the tire width direction. Further, in the illustrated example, all the width direction grooves 3 extend linearly along the tire width direction, but for example, at least one of the width direction grooves 3 may be bent in a zigzag shape, or It may be curved in a meandering manner.

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

In this example, a plurality of block-like land portions 5 are provided on both sides of the three rib-like land portions 4 in the tire width direction, arranged in the circumferential direction. The block-shaped land portion 5 of this example is divided by the circumferential grooves 2a, 2d, the tread end TE, and the 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 of one block-shaped land portion 5. As shown in FIG. In this example, the block-shaped land portion 5 includes a plurality of (four in the illustrated example) slit-shaped sipes 6 (61, 62, 63, 64) extending in the tire width direction, and each slit-shaped sipe 6. A pin-shaped sipe 7 extending radially inward from the bottom portion 6a is provided. The plurality of slit-shaped sipes 6 are arranged at intervals in the tire circumferential direction. The interval between two slit-shaped sipes 6 adjacent to each other in the tire circumferential direction (the interval in the tire circumferential direction) is not particularly limited.

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

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

Two pin-shaped sipes 7 are provided at the bottom 6a of the end-side slit-shaped sipe 61 at a distance from each other, and one pin-shaped sipe 7 is provided at the bottom 6a of the center-side slit-shaped sipe 62. is provided. In this example, the total volume of the two pin-shaped sipes 7 provided in the end-side slit-shaped sipe 61 is larger than the total volume of the one pin-shaped sipe 7 provided in the center-side slit-shaped sipe 62. ing.

Further, the two pin-shaped sipes 7 of the end-side slit-shaped sipe 61 are arranged symmetrically across the center line in the tire width direction of the block-shaped land portion 5, and the pin-shaped sipes 7 of the center-side slit-shaped sipe 62 is arranged at the center of the block-shaped land portion 5 in the tire width direction. In this way, the two pin-shaped sipes 7 of the end-side slit-shaped sipe 61 and the pin-shaped sipe 7 of the center-side slit-shaped sipe 62 are arranged at positions shifted in the tire width direction in the block-shaped land portion 5. ing.

Two pin-shaped sipes 7 are provided at the bottom 6a of the end-side slit-shaped sipe 64 at a distance from each other, and one pin-shaped sipe 7 is provided at the bottom 6a of the center-side slit-shaped sipe 63. is provided. The two pin-shaped sipes 7 of the end-side slit-shaped sipe 64 are arranged symmetrically across the center line in the tire width direction of the block-shaped land portion 5, and the pin-shaped sipes 7 of the center-side slit-shaped sipe 63 are 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 sipes 7 of the end-side slit-shaped sipe 64 and the pin-shaped sipe 7 of the center-side slit-shaped sipe 63 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, and 64 and the pin-shaped sipes 7 are arranged symmetrically across the tire circumferential center line 5c of the block-shaped land portion 5.

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

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

The tread surface 1 may have a block-shaped land portion 5 that does not have the slit-shaped sipes 6 and the pin-shaped sipes 7, or all the block-shaped land portions 5 have the slit-shaped sipes 6 and the pin-shaped sipes 7. It may be made to have. Further, the configuration of the rib-like land portions 4 (4a, 4b, 4c) is not particularly limited, and slit-like sipes and/or pin-like sipes 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 sipes 6 extend across the entire width 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. Note that the slit-shaped sipes 6 may extend obliquely with respect to the tire width direction. Further, one or both ends of the slit-shaped sipe 6 in the extending direction may terminate within the block-shaped land portion 5. Moreover, the slit-shaped sipe 6 is not limited to a straight-line shape as a whole along the extending direction, but may have a curved portion or a bent portion, as viewed from the tread surface shown in FIG. 1 .

The sipe width of the slit-like sipe 6 (opening width measured perpendicularly to the extending direction of the slit-like sipe 6 on the tread surface 1) can be, for example, 0.2 mm or more and 1.0 mm or less, and particularly , preferably 0.3 mm or more and 0.7 mm or less. In addition, although it is preferable that the sipe width of the slit-like sipe 6 is constant along the extending direction of the slit-like sipe 6 as in this example, the sipe width may vary along the extending direction. The slit-shaped sipe 6 preferably extends in a straight line in the tire radial direction (the depth direction of the slit-shaped sipe 6) from the opening 6b opening in the tread surface 1 to the bottom 6a. Without limitation, the slit-shaped sipe 6 may be inclined with respect to the tire radial direction, or may have a curved portion or a bent portion. Moreover, although it is preferable that the sipe width of the slit-like sipe 6 is constant along the depth direction of the slit-like sipe 6, 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 surface 1 to the bottom 6a) can be, for example, 1 mm or more and 20 mm or less, particularly 3 mm or more. , preferably 15 mm or less.

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

Note that the shape, 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 6a of one slit-shaped sipe 6. Moreover, 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 cylindrical shape as in this example, but may be, for example, a polygonal column shape, or a plurality of notches extending radially from the center of the pin-shaped sipe 7 when viewed from the tread surface. It is also possible to have a Y-shape or an X-shape.

The pin-shaped sipe 7 of this example has a constant cross-sectional shape (a cross section perpendicular to the extending direction (depth direction) of the pin-shaped sipe 7) from the upper end to the lower end of the pin-shaped sipe 7; The shape is not limited to this, 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 increases continuously or stepwise from the upper end to the lower end, or conversely, the diameter gradually increases from the upper end to the lower end of the pin-shaped sipe 7. It may be a shape in which the value is small.

The sipe diameter (maximum diameter when viewed from the tread surface) of the pin-shaped sipe 7 can be, for example, 0.2 mm or more and 5.0 mm or less, particularly 0.3 mm or more and 2.0 mm or less. preferable. Further, the diameter of the pin-shaped sipe 7 is preferably equal to or smaller than the sipe width of the slit-shaped sipe 6 in order to facilitate formation of the pin-shaped sipe 7. In addition, in the example 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 preferable to set it to 5.0 mm or less.

As described above, the tire of the present embodiment is a pneumatic tire including the block-shaped land portion 5 partitioned into the tread surface 1, and the block-shaped land portion 5 extends in the width direction of the tire. The plurality of slit-shaped sipes 6 have a plurality of slit-shaped sipes 6 that are open to each other, and a pin-shaped sipe 7 that extends inward in the tire radial direction from the bottom 6a of each slit-shaped sipe 6. , end-side slit-like sipes 61, 64 closest to the tire circumferential ends 5a, 5b of the block-shaped land portion 5, and center-side slit-like sipes adjacent to the end-side slit-like sipes 61, 64 on the center side in the tire circumferential direction. 62, 63, and the total volume of the pin-shaped sipes 7 provided in the end-side slit-shaped sipes 61, 64 is larger than the total volume of the pin-shaped sipes 7 provided in the center-side slit-shaped sipes 62, 63. It is characterized by being large. According to this configuration, by providing the pin-shaped sipes 7, the compression rigidity of the block-shaped land portion 5 during wear progresses is reduced, making it easier for the tread surface 1 to dig into the road surface. For example, in place of the pin-shaped sipe 7, a slit-shaped sipe extending to the depth of the lower end of the pin-shaped sipe 7 is provided (the depth of the slit-shaped sipe 6 is increased to the depth of the lower end of the pin-shaped sipe 7). In this case, there is a risk that the land portion may collapse, but in this embodiment, by providing the pin-shaped sipe 7 while maintaining the slit-shaped sipe 6 at an appropriate depth, such collapse of the land portion may be prevented. can be suppressed. As a result, it is possible to appropriately improve the grounding performance of the block-shaped land portion 5 when wear progresses. Moreover, since the total volume of the pin-shaped sipes 7 provided in the end-side slit-shaped sipes 61 and 64 is larger than the total volume of the pin-shaped sipes 7 provided in the center-side slit-shaped sipes 62 and 63, the block-shaped land The compression rigidity of the tire circumferential end portions 5a, 5b of the portion 5 is lower than the compression rigidity of the center portion, and the grounding performance of the block-shaped land portion 5 during braking can be improved. As a result, it is possible to improve the ground contact of the block-shaped land portion 5 during braking when wear progresses, and for example, the grip performance on a wet road surface when wear progresses can be improved.

In addition, in the tire of this embodiment, by providing the pin-shaped sipe 7 connected to the bottom 6a of the slit-shaped sipe 6, the contact between the road surface and the tread surface 1 is improved compared to 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 sipes 7 via the slit-shaped sipes 6, it is also possible to improve the drainage performance of the tire.

In addition, in the tire of this embodiment, since the slit-shaped sipes 6 extend in the tire width direction, edge components in the tire width direction (edges in the tire circumferential direction) until the pin-shaped sipes 7 are exposed. component), it is possible to improve the grip performance of the tire on a wet road surface up to the time when the pin-shaped sipes 7 are exposed.

Here, in the tire of this embodiment, it is preferable that the slit-shaped sipes 6 extend parallel to the tire width direction. With this 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 is improved until the pin-shaped sipe 7 is exposed as wear progresses. can be improved.

Note that the slit-shaped sipes 6 may extend at an angle with respect to the tire width direction, and in this case, the slit-shaped sipes 6 may extend at an angle of inclination of 45° or less with respect to the tire width direction. is preferable, and it is also preferable that the inclination angle is 30° or less. Moreover, it is preferable that the slit-shaped sipes 6 extend in a straight line along the tire width direction when viewed from the tread surface. 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 this embodiment, a plurality of pin-shaped sipes 7 are provided in the end-side slit-shaped sipes 61 and 64. According to this configuration, the compression rigidity at the tire circumferential end portions 5a, 5b of the block-shaped land portion 5 can be balanced in a better manner than when only one pin-shaped sipe 7 is provided in the end-side slit-shaped sipes 61, 64. can be reduced.

In addition, in the tire of this embodiment, the number of pin-shaped sipes 7 provided on the end-side slit-like sipes 61 and 64 is greater than the number of pin-like sipes 7 provided on the center-side slit-like sipes 62 and 63. It's more than that. According to this configuration, the total volume of the pin-shaped sipes 7 provided in the end-side slit-shaped sipes 61, 64 can be reduced without increasing the individual volume of the pin-shaped sipes 7 provided in the end-side slit-shaped sipes 61, 64. The volume can be made larger than the total volume of the pin-shaped sipes 7 provided in the central slit-shaped sipes 62 and 63.

Further, in the tire of this embodiment, the end side slit-like sipes 61 and 64 extend from the end portions 5a and 5b of the block-like land portion 5 in the tire circumferential direction to the tire circumferential direction length of the block-like land portion 5 by 25 mm. % within the range. According to this configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion 5 in the range where the ground contact performance during braking during wear progresses is likely to decrease, so that the compression stiffness during braking during wear progress can be more effectively reduced. The grounding properties of the block-shaped land portion 5 can be improved.

Here, FIG. 3 shows an example in which the slit-shaped sipe 6 has a branch part 6c between the opening part 6b opening in the tread surface 1 and the bottom part 6a. Note that FIG. 3 shows a cross section perpendicular to the extending direction of the slit-shaped sipe 6. That is, FIG. 3 shows a circumferential cross section of the tire when the slit-shaped sipes 6 extend in the tire width direction, for example, as shown in FIG. Note that the type of 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 of the four slit-shaped sipes 61, 62, 63, and 64 may have a branch portion 6c, or one to three of them may have a branch portion 6c. A configuration may be adopted in which only the slit-shaped sipes 6 (61, 62, 63, 64) have the branch portions 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 surface 1, and a branching portion 6c from the tread-side sipe portion 6d. It has a branched sipe portion 6e that branches and extends through.

The tread-side sipe portion 6d extends in the normal direction of the tread surface 1 (tire radial direction), and the branch sipe portion 6e extends horizontally in the tire circumferential direction in a cross-sectional view in the tire circumferential direction in FIG. It consists of a sipe portion 6f and two vertical sipe portions 6g extending in the normal direction of the tread surface 1. A pin-shaped sipe 7 is provided at the bottom 6a of each of the two vertical sipe portions 6g. According to this configuration, one slit-shaped sipe 6 branches into two during the wear progression process, so that the number of slit-shaped sipes 6 can be increased during the wear progression process. In addition, the number of the bottom portions 6a is greater than the openings 6b of the slit-like sipes 6 that open in the tread surface 1, and the positions of the bottom portions 6a are spread over a wide range, making it easy to arrange the pin-like sipes 7 over a wide range. The number of pin-shaped sipes 7 can also be increased easily. As a result, by increasing the number of slit-shaped sipes 6 during the wear progression process, the edge component can be increased, and by arranging many pin-shaped sipes 7 over a wide range, the ground contact performance is improved during the wear progression. can be increased. Further, from the viewpoint of improving ground contact during braking when wear progresses, it is preferable that the end-side slit-shaped sipes 61 and 64 are provided with branch portions 6c.

Note that the slit-shaped sipe 6 and pin-shaped sipe 7 described above can be manufactured, for example, by processing metal plates, casting, additive manufacturing (3D printer), etc., but are not limited to these methods.

The present invention can be applied not only to the slit-shaped sipe 6 described above but also to the lateral groove 8 having a groove width larger than the slit-shaped sipe 6. In this case, the pneumatic tire includes, for example, a block-shaped land portion 5 partitioned into the tread surface 1, as shown in FIG. It has a plurality of open lateral grooves 8 and a pin-shaped sipe 7 extending from the bottom of each lateral groove 8 toward the inner side in the tire radial direction. It has end side lateral grooves 81, 84 closest to the circumferential ends 5a, 5b, and center side lateral grooves 82, 83 adjacent to the tire circumferential center side of the end side lateral grooves 81, 84, and the end side lateral grooves 81, 84. The total volume of the pin-shaped sipes 7 provided in the central lateral grooves 82 and 83 is larger than the total volume of the pin-shaped sipes 7 provided in the central lateral grooves 82 and 83. Here, the lateral groove 8 is a groove that extends in the width direction of the tire and has an opening width of 2 mm or more on the tread surface 1 when the pneumatic tire is mounted on the applicable rim, filled with a specified internal pressure, and under no load. means.

This pneumatic tire also makes it possible to improve the ground contact of the block-shaped land portion 5 when wear progresses for the same reason as explained in the case of the slit-shaped sipe 6.

In this case, it is preferable that a plurality of pin-shaped sipes 7 are provided in the end side lateral grooves 81 and 84. According to this configuration, the compression rigidity of the block-shaped land portion 5 at the tire circumferential end portions 5a, 5b is reduced in a well-balanced manner, compared to the case where only one pin-shaped sipe 7 is provided in the end-side lateral grooves 81, 84. be able to.

In the above pneumatic tire, it is preferable that the number of pin-shaped sipes 7 provided in the end-side lateral grooves 81 and 84 is greater than the number of pin-shaped sipes 7 provided in the center-side lateral grooves 82 and 83. According to this configuration, the total volume of the pin-shaped sipes 7 provided in the end-side lateral grooves 81, 84 can be increased to the center side without increasing the individual volume of the pin-shaped sipes 7 provided in the end-side lateral grooves 81, 84. It can be made larger than the total volume of the pin-shaped sipes 7 provided in the lateral grooves 82 and 83.

In the above pneumatic tire, the end lateral grooves 81 and 84 are located within 25% of the tire circumferential length of the block-shaped land portion 5 from the tire circumferential ends 5a and 5b of the block-shaped land portion 5. It is preferable to do so. According to this configuration, it is possible to more reliably reduce the compressive rigidity of the block-shaped land portion 5 in the range where the ground contact during braking is likely to decrease during wear progress, so that the block-shaped land portion 5 can be more effectively reduced during braking. The grounding properties of the portion 5 can be improved.

In the above-mentioned pneumatic tire, it is preferable that the end side lateral grooves 81 and 84 have a branch part between the opening in the tread surface 1 and the bottom part. According to this configuration, the number of lateral grooves 8 can be increased during the wear progression process, and the pin-shaped sipes 7 can be easily arranged in a wide range, and the number of the pin-shaped sipes 7 can also be easily increased. As a result, the edge component due to the lateral grooves 8 can be increased, and the effect of improving the ground contact property due to the pin-shaped sipes 7 when wear progresses can be enhanced.

It is preferable that the lateral grooves 8 extend parallel to the tire width direction. With this configuration, during the wear progression process until the pin-shaped sipes 7 are exposed on the tread surface 1, the edge component in the tire width direction is increased, and the wear progression until the pin-shaped sipes 7 are exposed is increased. It is possible to improve the grip performance of tires on wet road surfaces.

The lateral groove 8 in this example extends in a straight line along the tire width direction (parallel to the tire width direction). The lateral groove 8 extends in 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 terminate within the block-shaped land portion 5. Note that the lateral grooves 8 may extend obliquely with respect to the tire width direction. Moreover, either end in the extending direction of the lateral groove 8 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 grooves 8 (the opening width measured perpendicularly to the extending direction of the lateral grooves 8 in the tread surface 1) can be, for example, 2 mm or more and 10 mm or less. Although it is preferable that the width of the lateral groove 8 is constant along the extending direction of the lateral groove 8 as in this example, the groove width may vary along the extending direction. Moreover, although it is preferable that the groove width of the lateral groove 8 is constant along the depth direction of the lateral groove 8, the groove width may vary along the depth direction. Further, the groove depth of the lateral grooves 8 (the length in the tire radial direction from the opening to the tread surface 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 embodiments and modified examples described above, and various modifications and changes can be made without departing from the scope of the claims.

1: Tread surface 2 (2a, 2b, 2c, 2d): Circumferential groove 3: Width groove 4 (4a, 4b, 4c): Rib-shaped land portion 5: Block-shaped land portion 5a, 5b: Block-shaped land portion 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 grooves 61, 64: Slit-shaped sipes on the end side 62, 63: Slit-shaped sipes on the center side 81, 84: Horizontal grooves on the end side 82, 83: Horizontal grooves on the center side

Claims (10)

A pneumatic tire comprising a block-shaped land portion partitioned into a tread surface, the pneumatic tire comprising:
The block-shaped land portion includes a plurality of slit-shaped sipes extending in the width direction of the tire and opening into the tread surface, and a pin-shaped portion extending inward in the tire radial direction from the bottom of each of the slit-shaped sipes. has a sipe,
The plurality of slit-like sipes include an end-side slit-like sipe closest to the end of the block-like land portion in the tire circumferential direction, and a center-side slit-like sipe adjacent to the end-side slit-like sipe on the center side in the tire circumferential direction. and has
A pneumatic tire characterized in that a total volume of pin-shaped sipes provided in the end-side slit-shaped sipes is larger than a total volume of pin-shaped sipes provided in the center-side slit-shaped sipes. The pneumatic tire according to claim 1, wherein the end-side slit-shaped sipe is provided with a plurality of the pin-shaped sipes. The pneumatic tire according to claim 1 or 2, wherein the number of pin-shaped sipes provided in the end-side slit-shaped sipe is greater than the number of pin-shaped sipes provided in the center-side slit-shaped sipe. Any one of claims 1 to 3, wherein the end-side slit-shaped sipe is located within 25% of the tire circumferential length of the block-shaped land portion from the tire circumferential end of the block-shaped land portion. Pneumatic tires listed in section. The pneumatic tire according to any one of claims 1 to 4, wherein the end-side slit-shaped sipe has a branch part between an opening opening in the tread surface and the bottom part. A pneumatic tire comprising a block-shaped land portion partitioned into a tread surface, the pneumatic tire comprising:
The block-shaped land portion extends in the width direction of the tire, and includes a plurality of lateral grooves each having an opening width of 2 mm or more in the tread surface and opening in the tread surface , and extending inward in the tire radial direction from the bottom of each of the lateral grooves. a pin-shaped sipe extending toward the
The plurality of lateral grooves have an end lateral groove closest to the tire circumferential end of the block-shaped land portion, and a center lateral groove adjacent to the tire circumferential center side of the end lateral groove,
A pneumatic tire characterized in that a total volume of pin-shaped sipes provided in the end-side lateral groove is larger than a total volume of pin-shaped sipes provided in the center-side lateral groove. The pneumatic tire according to claim 6, wherein the end side lateral groove is provided with a plurality of the pin-shaped sipes. The pneumatic tire according to claim 6 or 7, wherein the number of pin-shaped sipes provided in the end-side lateral groove is greater than the number of pin-shaped sipes provided in the center-side lateral groove. According to any one of claims 6 to 8, the end lateral groove is located within 25% of the tire circumferential length of the block-shaped land portion from the tire circumferential end of the block-shaped land portion. Pneumatic tires listed. The pneumatic tire according to any one of claims 6 to 9, wherein the end-side lateral groove has a branch part between an opening opening in the tread surface and the bottom part.

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