RU2804373C2 - Studded tire - Google Patents

Abstract

FIELD: automotive industry.

SUBSTANCE: studded tire (101) comprises a tread (102) in which a stud (103) is installed. The protector (102) has a predetermined direction R of rotation. The protector (102) includes blocks (105). Each of the blocks (105) includes an angular portion (106) protruding forward in the rotation direction R. The spike (103) is installed in at least one of the blocks (105). The spike (103) includes a main part embedded in the block (105) and a pin (120) protruding from the main part (110) in the radial direction of the tire. The main body has an upper flange (111) formed thereon, and the upper flange (111) includes a tapering portion (111A) in plane projection. The spike (103) is installed in the block (105) so that the tapered part (111A) and the corner part (106) are oriented in the same direction.

EFFECT: improved performance on snowy and icy road surfaces.

12 cl, 9 dwg

Description

Field of technology

The present invention relates to a studded tire.

State of the art

The studded tire has been developed as a tire that exhibits excellent performance on icy road surfaces. JP 6336409 describes a winter tire used as a studded tire. The tread contains blocks, and at least one of the blocks has a hole in which a stud pin is secured.

Typically the tenon pin is pressed into a hole formed in the block. That is, the tenon pin is pressed into the hole with great force and thus installed, simultaneously pressing and expanding the hole. In this case, the rubber is incompressible, and the volume of rubber (tension) that is pressed and pulled in by the cleat pin expands so that the surrounding groove narrows, and the volume of the groove decreases. Reducing the volume of the groove leads to the problem that the shear force of the snow column is reduced, and accordingly, the performance on snowy road surfaces deteriorates.

The present invention is made in view of the above circumstances, and the main object of the present invention is to provide a studded tire that can exhibit excellent performance on a snowy road surface as well as on an icy road surface.

Brief Description of the Invention The present invention relates to a studded tire including a stud and a tread on which the stud is mounted. The tread has a specified direction of rotation. The tread includes blocks. Each of the blocks includes an angular portion projecting forward in the direction of rotation. The spike is installed in at least one of the blocks. The stud includes a main portion embedded in a block and a pin projecting from the main portion in a radial direction of the tire. The main body includes an upper flange formed at a portion on the outer side in the radial direction of the tire. The upper flange includes a tapering part in projection onto the plane. The tenon is installed in the block so that the tapering part and the corner part are oriented in the same direction.

In another aspect of the present invention, the top flange may have a first side extending linearly in planar projection, and a tapered portion may have a length along the first side that decreases in a direction perpendicular to the first side.

In yet another aspect of the present invention, the corner portion may have an obtuse angle.

In yet another aspect of the present invention, the block may be a crown block located in a region that includes the equator of the tire at its center and extends a distance corresponding to 40% of the tread width.

In another aspect of the present invention, the block may be a shoulder block located in an area extending from the edge of the tread at a distance corresponding to 30% of the width of the tread.

In another aspect of the present invention, the tread may include a first tread edge and a second tread edge. The tread may include inclined grooves formed therein. The inclined grooves may include a first inclined groove extending from an open end connected to a first tread edge beyond the equator of the tire and having an unconnected end in front of a second tread edge, and a second inclined groove extending from an open end connected to a second tread edge beyond the equator of the tire, and having an unconnected end in front of the first edge of the tread. Each of the first inclined groove and the second inclined groove may include a first steeply inclined portion on the open end side that is inclined relative to the axial direction of the tire; a second steeply inclined portion on the unconnected end side that is inclined relative to the axial direction of the tire, and a gently inclined portion that is inclined relative to the axial direction of the tire and is located between the first steeply inclined portion and the second steeply inclined portion.

In yet another aspect of the present invention, the second steeply inclined portion may have a portion located at an angle relative to the longitudinal direction of the tire that gradually decreases toward the unconnected end.

In another aspect of the present invention, the tread may include first inclined grooves and second inclined grooves. Each of the first inclined grooves may intersect two or more inclined grooves between the equator of the tire and the second edge of the tread.

In another aspect of the present invention, each of the second inclined grooves may intersect two or more inclined grooves between the equator of the tire and the first edge of the tread.

In yet another aspect of the present invention, the gently sloping portion of the first inclined groove may have an angle with respect to the axial direction that gradually decreases toward the second edge of the tread. The gently inclined portion of the second inclined groove may have an angle with respect to the axial direction of the tire that gradually decreases toward the first edge of the tread.

In another aspect of the present invention, the first steeply angled portion may be curved so as to protrude to one side in the longitudinal direction of the tire. The gently sloping part may be bent so that it protrudes to the other side in the longitudinal direction of the tire.

In another aspect of the present invention, as viewed on the tread plane, the center of gravity of the stud top flange region may be located at a distance from the end of the corner portion of 15 mm or less in the longitudinal direction of the tire.

In another aspect of the present invention, as viewed on the tread plane, the center of gravity of the stud top flange region may be located at a distance from the end of the corner portion of 5 mm or less in the axial direction of the tire.

The studded tire of the present invention can exhibit excellent performance on icy road surfaces because the tread has a stud mounted thereon.

The tread includes blocks, and each block includes an angular portion projecting forward in the direction of rotation of the tire. The corner part of such a structure separates the snow in the direction to the left and in the direction to the right when driving on a snow-covered road surface, and a shearing force of the snow column can be generated on each side.

In addition, the upper flange of the tenon includes a tapered portion in projection onto the plane, and the tenon is installed such that the tapered portion and the corner portion of the block are oriented in the same direction. Thus, because the corner portion of the block and the tapered portion of the top flange are oriented in the same direction, the rubber is prevented from greatly expanding locally into the grooves surrounding the block when the stud is installed in the block, so that the shear force of the snow columns can also be prevented from being reduced. Thus, the studded tire of the present invention can exhibit excellent performance on a snowy road surface as well as on an icy road surface.

Brief description of drawings

In FIG. 1 is a partial view of a tread in accordance with one embodiment of the present invention;

in Fig. 2 is a perspective view of a tenon in accordance with one embodiment;

in Fig. 3 is a partial view of the tenon shown in FIG. 2;

in Fig. 4 is a side view of the tenon shown in FIG. 2;

in Fig. 5 is a cross-sectional view of a hole formed in the tread;

in Fig. 6 shows an incomplete enlarged view of the corner part of the block;

in Fig. 7 is an expanded view of a tire tread in accordance with one embodiment of the present invention;

in Fig. 8 is an enlarged view of the outline of the first inclined groove shown in FIG. 7, and

in Fig. 9 is an enlarged view of the main part shown in FIG. 7.

Description of Preferred Embodiments

Next, an embodiment of the present invention is described with reference to the drawings.

In FIG. 1 is an enlarged view of a main tread portion 102 of a studded tire (hereinafter may be referred to as a "tire") 101 in accordance with one embodiment of the present invention. The tire 101 includes studs 103 mounted on a tread 102. Each stud 103 is made of a material harder than the tread 102, which is made of rubber. A portion of the tenon 103 may come into contact with the ground during movement. Thus, the tire 101 is capable of generating high friction against the road surface, for example, by the studs 103 embedded in the road surface, thereby exhibiting excellent performance on icy road surfaces.

The tread 102 has a predetermined rotation direction R. For example, the rotation direction R is set such that the tread 102 and/or studs 103 improve the ride quality of the tire 101. In other words, the tread pattern 102 and/or studs 103 are preferably designed to exhibit optimal rotational properties of the tread 102 and/or studs. 103 in the direction R of rotation and contact with the road surface. The rotation direction R may be indicated, for example, on a sidewall (not shown) of the tire 101.

The tread 102 includes blocks 105 formed thereon. Each block 105 includes a corner portion 106 projecting forward in the rotation direction R. In the present embodiment, the corner portion 106 is configured to be the first in the block 105 to come into contact with the ground when the tire 101 is rotated in the rotation direction R. In a preferred embodiment, the corner portion 106 is designed such that it has a width in the tire axial direction that decreases in the rotation direction R. Therefore, high contact pressure acts on the corner portion 106 in the block 105 when driving with the tire. Moreover, it is needless to mention that grooves 108 are formed on both sides of the corner portion 106 in the tire axial direction.

The corner portion 106 can separate snow in the left direction and in the right direction when driving on a snow-covered road surface, guiding the snow into the grooves 108 on both sides. Snow directed into the grooves 108 on both sides of the corner portion 106 in the axial direction of the tire is compacted by the tire 101 as it further rotates. Thereafter, when the tire 101 rotates further, the column of snow in the groove 108 is shifted by the block 105, and the shear force of the snow column, which is a reaction force, at this time produces traction and braking forces in the tire 101. Thus, the tire 101 of the present embodiment , creates a shearing force for the column of snow on both sides of the corner portion 106, thereby exhibiting excellent performance on snow-covered road surfaces.

In a preferred embodiment, the corner portion 106 may be configured to have an obtuse angle, i.e. an angle α of more than 90 degrees and less than 180 degrees. Thus, the shear force of the snow column increases in the longitudinal direction of the tire, and the traction and braking forces during straight-line motion are also further increased. In particular, in a preferred embodiment, the corner portion 106 may be configured to have an angle α between 100 and 140 degrees.

The spike 103 is mounted on at least one of the blocks 105. In FIG. 2, Fig. 3 and Fig. 4 is a perspective view, a top view, and a side view, respectively, of a stud 103 that is not mounted on the tread 102. As shown in FIG. 2-4, the tenon 103 includes a body 110 and a pin 120.

The body 110 is embedded in the block 105. The body 110 is generally shaped like a shaft and includes, for example, a top flange 111. In the present embodiment, the top flange 111 forms an outer side portion of the body 110 in the tire radial direction. Therefore, when the stud 103 is installed in the tire 101, the upper flange 111 is located, for example, on the tread surface (see Fig. 1).

In the present embodiment, the upper flange 111 has a polygonal shape in planar projection. As used herein, examples of a polygonal shape include not only shapes where the straight sides directly intersect each other to form an angle, but also shapes where the corner is rounded to form an arc (however, the entire shape is not a complete circle). Examples of polygonal shape include triangular shape, pentagonal shape and hexagonal shape. The upper flange 111 has, for example, a first side S1 that extends almost straight. The first side S1 may have, for example, a maximum length L1 in the upper flange 111. The length L1 is, for example, no more than 10 mm.

As shown in FIG. 3, the upper flange includes a tapered portion 111A in planar projection. In the tapering portion 111A, for example, the length along the first side S1 gradually decreases in a direction perpendicular to the first side S1 (hereinafter referred to as “first direction D”). The tapered portion 111A in the present embodiment terminates to form a second side S2 of length L2 in a position opposite to the first side S1. Diagonal sides S3 and S3 are formed on both sides of the second side S2. The taper angle formed by the diagonal sides S3 and S3 is, for example, an obtuse angle, and is preferably 100 to 140 degrees.

The upper flange 111 may also include a portion that extends continuously along a length L1 in a first direction D, between the tapered portion 111A and the first side S1.

As shown in FIG. 2 and Fig. 4, in a preferred embodiment, the body 110 may also include a lower flange 112 defining an end portion on the inner side of the main body 110 in the tire radial direction, and a necked portion 113 located between the lower flange 112 and the upper flange 111. The necked portion 113 has an outer a diameter that is less than the diameter of each of the upper flange 111 and the lower flange 112.

The pin 120 is a relatively small protrusion that projects from the body 110 (more specifically, from the top flange 111) in the radial direction of the tire. The pin 120 primarily allows for high friction to be generated against the road surface by coming into contact with the road surface. 120 pins of various shapes can be used.

In the present embodiment, the pin 120 may include a recess 122 that extends toward the inside of the pin in plan view, as shown in FIG. 3. The recess 122 defines a groove in the pin 120, for example, extending in the radial direction of the tire, and assists in pressing the pin 120 into the road surface, thereby further enhancing the high friction against the road surface.

The pin 120 may include a projection 123 that has a length perpendicular to the first direction D that decreases in the first direction D as projected onto the plane shown in FIG. 3. Preferably, the protrusion 123 is provided on the side opposite to the side of the recess 122 in the first direction D. The protrusion 123 so configured also helps to press the pin 120 into the road surface, thereby contributing to a higher friction contact state.

The material of the stud 103 is not particularly limited as long as the stud 103 is made of a material harder than rubber. However, the tenon 103 is preferably made of a metallic material. In another embodiment, the stud 103 may be made of a resin or rubber material harder than the rubber of the tread 102. Additionally, in the stud 103, for example, the material of the body 110 may be different from the material of the pin 120.

In FIG. 5 is a cross-sectional view of the tread 102 in which the stud 103 is not installed. As shown in FIG. 5, the tread 102 includes a hole 130 into which a stud 103 is installed. The hole 130, for example, is a circular hole when projected onto a plane. The hole 130, for example, has increased inner diameters on the outer side and inner side in the tire radial direction, and a reduced inner diameter therebetween. This shape corresponds to the shape of the main part 110 of the tenon 103, shown by an imaginary line. In addition, the hole 130 has an inner diameter that is smaller than the outer diameter of the tenon 103 over almost the entire length of the hole 130.

When the tenon 103 is installed in the hole 130, the tenon 103 is pressed into the hole 130 with great force. Thus, the tenon 103 is inserted into the hole 130, pressing and expanding the hole 130, and is installed such that the main part 110 including the upper flange 111 is placed in the hole 130, and the pin 120 is placed outside the hole 130. The hole 130 elastically deforms so that it comes into almost complete intimate contact with the body 110 of the stud 103, and it firmly holds the stud 103. The rubber drawn in by the stud 103 expands toward the groove 108 around the block 105.

Returning to Fig. 1, in the present embodiment, the stud 103 is installed in the block 105 so that the tapered portion 111A of the upper flange is oriented in the same direction as the corner portion 106 of the block 105 to improve the snow-covered performance of the studded tire 101. Although the tapered portion 111A is angular portion 106 are oriented in the same direction, the rubber of the block 105 expands greatly locally into the groove 108 around the block 105 when the spike 103 is installed in the block 105, and thus the volume of the groove is reduced, and the reduction in the volume of the groove reduces the shear force of the snow column.

Meanwhile, as in the present embodiment, when the corner portion 106 of the block 105 and the tapered portion 111A of the upper flange 111 are oriented in the same direction, significant local expansion of the rubber of the corner portion 106 of the block 105 into the grooves 108 around the block 105 is suppressed, also when the tenon 103 is installed in block 105.

In FIG. 6 schematically shows by arrows the stress generated around the hole 130 when the tenon 103 is installed. As can be seen from FIG. 6, in the present embodiment, the stress is higher near the first side S1 of the top flange 111, while the stress is relatively low between the hole 130 and the end portion 106A of the corner portion 106. As a result, significant local expansion of the rubber of the corner portion 106 into the grooves 108 around the corner portion 106 is suppressed. , so that the shear force of the snow column can be prevented from decreasing. Therefore, the tire 101 of the present embodiment suppresses the reduction in the shear force of the snow column and can maintain excellent performance on snowy road surfaces also with the stud 103 installed.

As shown in FIG. 1, the tapered portion 111A of the upper flange 111 is preferably positioned to project forward in the rotation direction R, similar to the corner portion 106 of the block 105.

In FIG. 6 is an enlarged top view of the corner portion of the block 105. As shown in FIG. 6, in a preferred embodiment, the upper flange 111 of the stud 103 is positioned to be intersected in the tire longitudinal direction by a line Y that passes through the end portion 106A of the corner portion 106 of the block 105 as projected onto the plane of the block 105. Thus, when the stud 103 is installed, the expansion The rubber is distributed on both sides of the corner portion 106 with good balance, and expansion into the grooves 108 can be further reduced.

In a preferred embodiment, as viewed on the plane of the tread 102 (FIG. 6), the center of gravity SG of the region of the upper flange 111 of the stud 103 may be located at a distance from the end portion 106 of the corner portion 106 of 15 mm or less in the longitudinal direction of the tire. Likewise, in the preferred embodiment, as viewed on the plane of the tread 102 (FIG. 6), the center of gravity SG of the region of the upper flange 111 of the stud 103 may be located at a distance from the end portion 106A of the corner portion 106 of 5 mm or less in the axial direction of the bus. Thus, when the stud 103 is installed, the expansion of the rubber is distributed on both sides of the corner portion 106 with improved balance, and the expansion into the grooves 108 can be further suppressed. In this case, it should be noted that the tenon 103 is located so that the perimeter of the tenon 103 is covered with rubber without expansion from the block 105.

In a preferred embodiment, as viewed on the plane of the tread 102 (FIG. 6), the angle between the diagonal side S3 of the tapered portion 111A of the stud 103 and the block edge 106E of the corner portion 106 is, for example, no more than 20 degrees, preferably no more than 15 degrees, more preferably no more than 10 degrees and even more preferably 0 degrees (that is, the diagonal side S3 and the block edges 106E are parallel to each other). Thus, when the stud 103 is installed, the expansion of the rubber is distributed on both sides of the corner portion 106 in a more balanced manner, and the expansion into the grooves 108 can be further reduced.

As shown in FIG. 1, the block 105 in which the tenon 103 is installed may be a crown block. The crown block is located in a crown region including the tire equator C at its center and extending a distance corresponding to 40% of the tread width (described below). The crown block may be positioned such that the center of gravity position of the crown block tread surface is in the crown region, and a portion of the crown block may be outside the crown region. During straight-line motion, the crown block is subjected to a relatively high contact pressure. Therefore, when the above relationship with the tenon 103 is applied to the crown block, the shearing force of the snow column is applied more effectively in straight-line driving, and straight-line driving performance and braking performance on snow-covered road surfaces are further improved.

The block 105 may be a shoulder block. The shoulder block 105 is located in a shoulder region extending from the tread (described below) at a distance corresponding to 30% of the tread width. The shoulder block may be positioned such that the position of the center of gravity of the tread surface of the shoulder block is in the shoulder region, and a portion of the shoulder block may be outside the shoulder region. When cornering, high contact pressure is applied to the shoulder block. Therefore, when the above relationship with the tenon 103 is applied to the shoulder block, the shearing force of the snow column is applied more effectively when cornering, and the cornering performance on a snow-covered road surface is further improved.

The embodiment of the protector

In FIG. 7 shows bus 1 as a preferred embodiment of bus 101. FIG. 7 is an expanded view of a tread 2 of a tire 1. The tire 1 includes a tread 2 defined by a first tread edge Te1 and a second tread edge Te2.

The tread 2 includes, for example, a first tread portion 2A between a tire equator C and a first tread edge Te1 and a second tread portion 2B between a tire equator C and a second tread edge Te2. The first tread portion 2A and the second tread portion 2B are substantially linearly symmetrical except that the first tread portion 2A and the second tread portion 2B are offset in the longitudinal direction of the tire. Therefore, each component of the first tread portion 2A can be used in the second tread portion 2B.

The first tread edge Te1 and the second tread edge Te2 represent the axial outer contact positions of the tire with the ground when the tire 1 is in normal contact with the plane, when the camber angle is 0° under normal load, when the tire 1 is pneumatic tire

The "normal state" is a state where the tire 1 is mounted on a normal rim at a normal pressure and no load is applied to the tire 1. In this document, unless otherwise indicated, the dimensions of tire components 1, etc. are presented as values measured in the normal state.

A "normal rim" is a wheel rim defined by a standard for each tire in a standardization system including the standard to which the tire conforms, and for example, it is a "standard rim" in the JATMA (Japan Automobile Tire Manufacturers Association) standard, a "design rim" in the TRA (American Rim and Tire Association) standard and “measured rim” in the ETRTO (European Rim and Tire Technical Organization) standard.

"Normal inflation pressure" is the air pressure specified by the standard for each tire in the standardization system that includes the standard to which the tire conforms, and for example, it represents the "maximum air pressure" in the JATMA standard, the maximum value given in the table "Load Limits" tires at different cold inflation pressures" in the TRA standard, and "inflation pressure" in the ETRTO standard.

The "normal tire load" is the tire load determined by the standard for each tire in the standardization system including the standard to which the tire complies, and it represents the "maximum load capacity" in the JATMA standard, the maximum value given in the above table in the TRA standard, and "carrying capacity" in the ETRTO standard.

The tread 2 contains inclined grooves 10 running diagonally relative to the axial direction of the tire. The inclined grooves 10 include first inclined grooves 11 and second inclined grooves 12.

Each first inclined groove 11 extends from an open end 11a, which is connected to the first tread edge Te1, beyond the tire equator C, and has an unconnected end 11b in front of the second tread edge Te2.

Each second inclined groove 12 extends from an open end 12 that is connected to the second tread edge Te2, beyond the tire equator C, and has an unconnected end 12b in front of the first tread edge Te1. The second inclined grooves 12 have substantially the same design as the first inclined grooves 11. Thus, unless otherwise specified, the design of the first inclined groove 11 can be used for the second inclined groove 12.

The first inclined grooves 11 and the second inclined grooves 12 pass through the equator C of the tire and not only exhibit high drainage properties when driving on a wet road surface, but also form columns of snow elongated in the axial direction of the tire when driving on a snowy road surface, creating a large force shifting columns of snow.

The inclined grooves 10 may include, for example, inclined auxiliary grooves having a length in the tire axial direction that is less than the length of each of the first inclined groove 11 and the second inclined groove 12.

The inclined auxiliary grooves include, for example, the first inclined auxiliary grooves 14 and/or the second inclined auxiliary grooves 15.

For example, each first inclined auxiliary groove 14 extends from an open end 14a connected to the first tread edge Te1 beyond the tire equator C and includes a non-connected end 14b at a position closer to the tire equator C than the non-connected end 11b of the first inclined groove 11 In the present embodiment, in the first tread portion 2A, the first inclined grooves 11 and the first inclined auxiliary grooves 14 alternate in the longitudinal direction of the tire.

For example, each second inclined auxiliary groove 15 extends from the open end 15a connected to the second tread edge Te2 beyond the tire equator C and includes a non-connected end 15b at a position closer to the tire equator C than the non-connected end 12b of the second inclined groove 12 In the present embodiment, in the second tread portion 2B, the second inclined grooves 12 and the second inclined auxiliary grooves 15 alternate in the longitudinal direction of the tire.

In a preferred embodiment, each inclined groove 10 is inclined in the rotation direction R from the tread edge Te1, Te2 to the tire equator C.

For example, the width W1 of the inclined groove 10 is preferably 2.0% to 6.0% of the tread width TW. For example, preferably, the groove width W1 gradually decreases from the open end side towards the unconnected end. The tread width TW is the distance in the axial direction of the tire from the first tread edge Te1 to the second tread edge Te2 in a normal state.

For example, the depth of the inclined groove 10 is 6.0 to 12.0 mm, and preferably 8.0 to 10.0 mm in the case of a passenger car tire.

Each of the first inclined groove 11 and the second inclined groove 12 includes a first open-end side steeply sloped portion 16 that is inclined relative to the tire axial direction, a second non-connected end side steeply sloped portion 17 that is inclined relative to the tire axial direction, and a flat slope portion 18 that is inclined relative to the axial direction of the tire between the first steep slope portion 16 and the second steep slope portion 17.

The gently inclined portion 18 extends at an angle relatively close to the axial direction angle of the tire. High contact pressure acts on the gently sloping portion 18 during straight-line motion. Thus, the gently inclined part 18 allows a large shear force of the snow column to be generated in the longitudinal direction of the tire during straight-line movement on a snow-covered road surface.

Here, the first steeply inclined portion 16 and the second steeply inclined portion 17 extend at an angle that is relatively close to the tire pitch angle. The contact pressure acting on the first steeply inclined portion 16 and the second steeply inclined portion 17 is high during cornering. Thus, the first steeply inclined portion 16 and the second steeply inclined portion 17 provide a large snow column shear force generated in the axial direction of the tire when cornering on a snowy road surface, and therefore help improve cornering performance on a snowy road surface.

In the first inclined grooves 11 and the second inclined grooves 12, a gently sloping portion 18 is disposed between the first steeply sloping portion 16 and the second steeply sloping portion 17, each having excellent drainage properties. This improves performance on snow-covered road surfaces with minimal reduction in drainage properties in the part 18 with a gentle slope.

The second steeply inclined portion 17 may include a portion in which the angle relative to the longitudinal direction of the tire gradually decreases toward the unconnected end. The steeply sloping second portion 17 of this structure helps direct water into the sloping groove 10 toward the unconnected end or open end by rotating the tire. Thus, the inclined grooves 10 can also exhibit excellent drainage properties.

For example, each first inclined groove 11 preferably intersects two or more inclined grooves 10 between the tire equator C and the second tread edge Te2. For example, each first inclined groove 11 more preferably intersects three or more inclined grooves 10 and even more preferably intersects four or more inclined grooves 10 between the tire equator C and the second tread edge Te2. In this way, a plurality of snow columns can be formed in areas where the first inclined groove 11 and the other inclined grooves 10 intersect with each other when driving on a snow-covered road surface, and a greater shearing force of the snow columns can be obtained.

From this point of view, for example, every second inclined groove 12 preferably intersects two or more inclined grooves 10 between the tire equator C and the first tread edge Te1. For example, every second inclined groove 12 more preferably intersects three or more inclined grooves and even more preferably intersects four or more inclined grooves 10 between the tire equator C and the first tread edge Te1.

In the present embodiment, all intersection portions in which the inclined grooves 10 intersect each other are formed as intersections. However, the present invention is not limited to this. Any of the intersection sections can be branched into three branches.

A steeply sloping first groove portion 16 extends, for example, from the open end 11a to a portion in front of the tire equator C. In the present embodiment, for example, the first steeply sloping portion 16 extends through the center portion of the first tread portion 2A in the tire axial direction.

The angle θ1 of the first steeply inclined part 16 relative to the axial direction is, for example, from 15 to 70°. For example, the angle of the first steeply inclined portion 16 relative to the axial direction of the tire gradually decreases from the open end IIa side toward the equator C of the tire.

For example, the first steeply sloping portion 16 is preferably curved so as to project to one side in the longitudinal direction of the tire. For example, the steeply inclined first portion 16 may be curved so as to project rearward in the rotation direction R. The first steeply inclined part 16, which is so constructed, forms a column of snow that is bent in the shape of an arc when driving on a snow-covered road surface. Such a column of snow experiences a greater shear force in the forward direction in the rotation direction R, and this helps to improve the braking performance on snow-covered road surfaces.

For example, the gently sloping portion 18 extends through the equator C of the tire. For example, the end of the gently sloping portion 18 on the side of the first tread edge Te1 may be located closer to the tire equator C than the average position of the first tread portion 2A in the tire axial direction. Likewise, for example, the end of the gently sloping portion 18 on the side of the second tread edge Te2 may be located closer to the tire equator C than the average position of the second tread portion 2B in the tire axial direction.

The angle θ2 of the gently inclined portion 18 relative to the axial direction is smaller than the largest angle of the first steep inclined portion 16 relative to the axial direction of the tire. For example, the angle 92 of the flat slope part 18 ranges from 5 to 39°.

For example, the angle θ2 of the flat inclination portion 18 of the first inclined groove 11 relative to the tire axial direction gradually decreases toward the second tread edge Te2. Likewise, the angle θ3 of the second inclined groove portion 18 with respect to the tire axial direction gradually decreases toward the first tread edge Te1. The flat slope portion 18 so constructed allows water contained therein to be easily moved to one side in the axial direction of the tire when driving on a wet road surface.

For example, the gently sloping portion 18 is preferably curved so that it projects in a direction opposite to the direction in which the first steeply sloping portion 16 projects. More specifically, the gently sloping portion 18 may be curved so as to project forward in the rotation direction R. The flat slope portion 18 so constructed forms a column of snow that is bent in an arc shape in a direction opposite to the bending direction of the snow column formed by the first steep slope portion 16 when driving on a snow-covered road surface, so that the traction performance on a snow-covered road surface is can be effectively improved.

The second part 17 with a steep slope is located between the equator of the tire and the second edge Te2 of the tread. In the present embodiment, for example, the second portion 17 with a steep slope extends through the middle position of the second tread portion 2B in the tire axial direction. In the present embodiment, for example, the second steeply inclined portion 17 includes a main portion 17a with an angle relative to the tire longitudinal direction that gradually decreases from the gently inclined portion 18 toward the unconnected end 11b, and an end portion 19 connected to the main portion 17a. For example, the length of the main portion 17a is preferably at least 50% of the entire length of the second steeply sloping portion 17, and more preferably at least 70% of its length. At least two inclined grooves 10 intersect the main body 17a.

For example, the second steeply inclined portion 17 is inclined relative to the tire axial direction at an angle θ4 that is larger than the angle of the shallowly inclined portion 18. The angle 94 of the second steeply inclined portion 17 relative to the axial direction of the tire is, for example, 40 to 70°.

For example, the main portion 17a of the second steeply sloped portion 17 is preferably curved so as to project in the same direction as the first steeply sloped portion 16. The second part 17 with a steep slope of this design makes it possible to create a large shear force of the snow columns in the same direction as the first part 16 with a steep slope.

For example, preferably, the angle of the end portion 19 of the second steeply inclined portion 17 with respect to the longitudinal direction of the tire gradually decreases toward the unconnected end 11b.

In FIG. 8 is an enlarged view of the outline of the first inclined groove 11, and this drawing illustrates the structure of the first inclined groove 11 and the second inclined groove 12 in more detail.

As shown in FIG. 8, each first inclined groove 11 may include a plurality of intersection portions where the first inclined groove 11 intersects other inclined grooves 10. Each intersection portion has an intersection point at which a center line of a groove of the first inclined groove 11 and a center line of another inclined groove 10 intersect each other. . In the present embodiment, for example, the first inclined groove 11 includes a first intersection point 21, a second intersection point 22, and a third intersection point 23 in a region between the first tread edge Te1 and the tire equator C.

The first intersection point 21 is an intersection point in the intersection portion that is closest to the first tread edge Te1. The second intersection point 22 is an intersection point in the intersection portion that is adjacent to the first intersection point 21 and located closer to the second tread edge Te2 than the first intersection point 21. The third intersection point 23 is an intersection point in the intersection portion that is adjacent to the second intersection point 22 and located closer to the second tread edge Te2 than the second intersection point 22.

For example, the first inclined groove 11 includes a fourth intersection point 24, a fifth intersection point 25, a sixth intersection point 26, and a seventh intersection point 27 in a portion between the second tread edge Te2 and the tire equator C.

The fourth intersection point 24 is an intersection point on an intersection portion that is adjacent to the third intersection point 23 and located closer to the second tread edge Te2 than the third intersection point 23. The fifth intersection point 25 is an intersection point in the intersection portion that is adjacent to the fourth intersection point 24 and is located closer to the second tread edge Te2 than the fourth intersection point 24. The sixth intersection point 26 is an intersection point in the intersection portion that is adjacent to the fifth intersection point 25 and located closer to the second tread edge Te2 than the fifth intersection point 25. The seventh intersection point 27 is an intersection point in the intersection portion that is adjacent to the sixth intersection point 26 and is located closer to the second tread edge Te2 than the sixth intersection point 26, and the seventh intersection point 27 is located as close as possible to the second tread edge Te2.

In the present embodiment, the first steeply inclined portion 16 is located between the open end 11a and the third intersection point 23. For example, the angle θ5 of the first straight line 20a relative to the axial direction of the tire is preferably 19 to 29°. The first straight line 29a is a line extending from the intersection point at which the first tread edge Te1 and the center line of the first inclined groove 11 intersect each other to the first intersection point 21. For example, the angle θ6 of the second straight line 29b with respect to the axial direction of the tire is preferably 29 to 45°. The second straight line 29b is a line extending from the first intersection point 21 to the second intersection point 22. For example, the angle θ7 of the third straight line 29 with respect to the axial direction of the tire is preferably from 49 to 55°. The third straight line 29c is a line extending from the second intersection point 22 to the third intersection point 23.

For example, the distance L1 in the tire axial direction from the tire equator C to the third intersection point 23 is preferably 0.05 to 0.15 times the tread width TW.

The first inclined grooves 11, as described above, contribute to a balanced improvement of performance on snowy road surfaces and driving stability on dry road surfaces.

In the present embodiment, the shallow slope part 18 is located between the third intersection point 23 and the fourth intersection point 24. For example, the angle θ8 of the fourth straight line 20d relative to the axial direction of the tire is preferably 15 to 25°. The fourth straight line 20d is a line extending from the third intersection point 23 to the fourth intersection point 24.

For example, the distance L2 in the tire axial direction from the tire equator C to the fourth intersection point 24 is preferably 0.05 to 0.15 times the tread width TW.

In the present embodiment, the second steeply inclined portion 17 is located between the fourth intersection point 24 and the seventh intersection point 27. For example, the angle θ9 of the fifth straight line 20e with respect to the longitudinal direction of the tire is preferably 50 to 60°. The fifth straight line 20e is a line extending from the fourth intersection point 24 to the fifth intersection point 25.

For example, the angle θ10 of the sixth straight line 20f with respect to the longitudinal direction of the tire is preferably 35 to 50°. The sixth straight line 20f is a line extending from the fifth intersection point 25 to the sixth intersection point 26.

For example, the angle θ11 of the seventh straight line 20g with respect to the tire longitudinal direction is preferably 20 to 30°. The seventh straight line 20g is a line extending from the sixth intersection point 26 to the seventh intersection point 27.

For example, the distance L3 in the tire axial direction from the second tread edge Te2 to the unconnected end 11b is preferably 0.05 to 0.15 times the tread width TW.

The first inclined groove 11, as described above, allows for improved performance on snowy road surfaces and wet road surfaces, while maintaining rigidity near the second edge Te2 of the tread.

As shown in FIG. 7, the first inclined auxiliary groove 14 includes a first steeply inclined portion 16 and a gently inclined portion 18, similar to the first inclined groove 11. The structure of the first steeply inclined portion 16 and a gently inclined portion 18 of the first inclined groove 11 described above is applicable to the first part 16 with a steep slope and the part 18 with a gentle slope of the first inclined auxiliary groove 14.

For example, the distance L4 in the tire axial direction from the tire equator C to the unconnected end 14b of the first inclined auxiliary groove 14 is preferably 0.30 to 0.40 times the tread width TW.

The second inclined auxiliary groove 15 includes a first steeply inclined portion 16 and a gently inclined portion 18, similar to the second inclined groove 12. The design of the first steeply inclined portion 16 and the gentle inclined portion 18 of the second inclined groove 12 described above is applicable to the first portion. 16 with a steep inclination and a portion 18 with a gentle inclination of the second inclined auxiliary groove 15. Moreover, the first inclined auxiliary groove 14 and the second inclined auxiliary groove 15 are substantially linearly symmetrical, except that the first inclined auxiliary groove 14 and the second inclined auxiliary groove The groove is shifted in the longitudinal direction. Therefore, the structure of the first inclined auxiliary groove 14 described above is also applicable to the second inclined auxiliary groove 15.

Thanks to the tread 2 having the inclined grooves 10 described above, the tread 2 has blocks 105 formed thereon.

In FIG. 9 is an enlarged view of a main portion of the first tread portion 2A. As shown in FIG. 9, the first tread portion 2A is divided into five kinds of blocks 1050, 1051, 1052, 1053 and 1054. For example, each block includes zigzag sipes. In this document, the lamella is a slot less than 1.5 mm wide.

The block 1050 includes first lamellas 41. For example, each first lamella 41 is preferably inclined in a direction opposite to the direction in which the first inclined groove 11 is inclined.

The block 1051 includes second sipes 42. For example, although each second sipes 42 are inclined in the same direction as the first sipes 41, the angle of the second sipes 42 relative to the tire axial direction is less than the angle of the first sipes 41 relative to that direction. The first lamellas 41 and the second lamellas 42 of this design allow, through their edges, to increase the friction force in a direction different from the direction of the first inclined grooves 11.

The block 1052 includes third sipes 43. For example, although each third sipes 43 are inclined in the same direction as the first sipes 41, the third sipes 43 extend at an angle relative to the axial direction of the tire that is less than the angle of the first sipes 41.

Block 1053 includes fourth slats 44. Block 1054 includes fifth slats 45. For example, fourth slats 44 and fifth slats 45 are inclined in the same direction as second slats 42. In the present embodiment, for example, fourth slats 44 and fifth slats 45 extend lengthwise 42 second lamellas.

Each of the blocks 1050, 1053 and 1054 includes a hole 130 into which a tenon 103 is installed. One skilled in the art will recognize that the block 1050 is of substantially the same design as the block 105 shown on the left side in FIG. 1. In a preferred embodiment, the grooves and slats are not located in a circumferential area extending from the center of the hole 130 to a distance of 8 mm or less. In this way, the occurrence of cracks around the hole 130 is suppressed.

In the tire 1 of the present embodiment, for example, the area ratio Lr in the tread 2 is preferably 55% to 70%. Thus, driving stability on dry road surfaces and performance on snowy road surfaces are improved with a good balance. As used herein, "area ratio" is the ratio Sb/Sa of the total actual contact area Sb to the total area Sa of the imaginary contact surface obtained by filling all the grooves and slats.

From the same point of view, for example, the hardness Ht of the rubber of the tread 2 is preferably from 45 to 65°. As used herein, "rubber hardness" is the hardness measured using an A-type durometer at a temperature of 23°C in accordance with JIS-K6253.

Although a tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the above specific embodiment, and various modifications can be made to implement the present invention.

Examples

Two types of studded tires were obtained using the studs 1 and 2 described above disposed in the tires, and the basic pattern of the tires is shown in FIG. 7. A professional driver assessed the driving characteristics of two types of studded tires on icy and snowy road surfaces.

Characteristics of spike 1 (example according to the invention)

Length L1 of the first side S1 of the top flange: 6 mm

Length L2 of the second side S2 of the top flange: 2 mm

Distance between first side and second side: 4mm

Tapering angle: 120 degrees

The tapered portion was oriented in the direction shown in FIG. 1.

Characteristics of spike 2 (comparative example)

The top flange had a square contour shape (without a tapered portion) and the same surface area as the area of the tenon 1, and the sides were aligned in the longitudinal direction of the tire and in the axial direction of the tire.

Both tires achieved superior performance results on icy road surfaces due to the stud effect. Moreover, in terms of performance on snowy road surfaces, the tire of the example of the invention was superior in driving stability and grip performance to the tire of the comparative example. In particular, according to the professional driver's feeling, the snow driving rating was the highest at 10, and the results showed that the performance of the tire of the example of the invention was improved by about 10% or more compared with the tire of the comparative example.

Claims (44)

1. Studded tire (1, 101), including: spike (103) and protector (2, 102), in which the spike (103) is installed, where the tread (2, 102) has a given direction (R) of rotation, protector (2, 102) includes blocks (105), each block (105) includes an angular portion (106) projecting forward in the rotation direction (R), the spike (103) is installed in at least one of the blocks (105), the stud (103) includes a body (110) embedded in the block (105) and a pin (120) projecting from the body (110) in the radial direction of the tire, the main body (110) includes an upper flange (111) formed on the outer side in the radial direction of the tire, the upper flange (111) includes a tapered portion (111A) in plane projection, and the tenon (103) is installed in the block (105) so that the tapered part (111A) and the corner part (106) are oriented in the same direction, wherein the corner part (106) has an obtuse angle. 2. Studded tire (1, 101) according to claim 1, in which the upper flange (111) includes a first side (S1) extending linearly in projection onto the plane, and the tapering portion (111A) has a length along the first side (S1) that tapers in a direction perpendicular to the first side (S1). 3. The studded tire (1, 101) according to claim 1 or 2, wherein the block (105) is a crown block located in a region including the equator (C) of the tire at its center and extending a distance corresponding to 40% of the width ( TW) tread. 4. Studded tire (1, 101) according to claim 1 or 2, wherein the block (105) is a shoulder block located in a region extending from the edge (Te1, Te2) of the tread to a distance corresponding to 30% of the width (TW) tread. 5. Studded tire (1, 101) according to any one of claims 1 to 4, in which the tread (2, 102) includes a first tread edge (Te1) and a second tread edge (Te2), the protector (2, 102) contains inclined grooves (10) formed on it, inclined grooves (10) include: a first inclined groove (11) that extends from an open end (11a) that is connected to the first tread edge (Te1) beyond the tire equator (C) and has an unconnected end (11b) in front of the second tread edge (Te2), and a second inclined groove (12) extending from an open end (12a) that is connected to the second edge (Te2) of the tread, beyond the equator (C) of the tire and having an unconnected end (12b) in front of the first edge (Te1) of the tread, and each of the first inclined grooves (11) and the second inclined grooves (12) includes: a first part (16) with a steep slope on the open end side (11a, 12a), which is inclined relative to the axial direction of the tire, a second part (17) with a steep slope on the side of the unconnected end (11b, 12b), which is inclined relative to the axial direction of the tire, and a gently inclined portion (18) that is inclined relative to the axial direction of the tire, between the first steeply inclined portion (16) and the second steeply inclined portion (17). 6. The studded tire (1, 101) according to claim 5, wherein the second steeply inclined portion (17) comprises a portion that has an angle relative to the longitudinal direction of the tire that gradually decreases toward the unconnected end (11b, 12b). 7. Studded tire (1, 101) according to claim 5 or 6, in which the tread (2, 102) includes first inclined grooves (11) and second inclined grooves (12), and each of the first inclined grooves (11) intersects two or more inclined grooves (10) between the equator (C) of the tire and the second edge (Te2) of the tread. 8. A studded tire (1, 101) according to any one of claims 5 to 7, wherein each of the second inclined grooves (12) intersects two or more inclined grooves (10) between the equator (C) of the tire and the first edge (Te1) of the tread . 9. Studded tire (1, 101) according to any one of claims 5 to 8, in which the gently sloping part (18) of the first inclined groove (11) has an angle with respect to the tire axial direction that gradually decreases towards the second edge (Te2) of the tread, and the gently sloping part (18) of the second inclined groove (12) has an angle with respect to the axial direction of the tire, which gradually decreases towards the first edge (Te1) of the tread. 10. Studded tire (1, 101) according to any one of claims 5 to 9, in which the first part (16) is steeply inclined so as to protrude to one side in the longitudinal direction of the tire, and part (18) with a gentle slope is curved so that it protrudes to the other side in the longitudinal direction of the tire. 11. Studded tire (1, 101) according to any one of claims 1 to 10, in which in projection onto the tread plane (2, 102), the center of gravity (SG) of the upper flange region (111) of the stud (103) is located at a distance from the end portion (106A) of the corner portion (106) of 15 mm or less in the longitudinal direction of the tire. 12. Studded tire (1, 101) according to any one of claims 1 to 11, in which in projection onto the tread plane (2, 102), the center of gravity (SG) of the upper flange region (111) of the stud (103) is located at a distance from the end portion (106A) of the corner portion (106) of 5 mm or less in the axial direction of the tire.

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