WO2021085004A1

WO2021085004A1 - Pneumatic tire

Info

Publication number: WO2021085004A1
Application number: PCT/JP2020/036755
Authority: WO
Inventors: 孝志芝井
Original assignee: 横浜ゴム株式会社
Priority date: 2019-11-01
Filing date: 2020-09-29
Publication date: 2021-05-06
Also published as: FI20225419A1; JP2021070449A; JP7172953B2; CN114599531A; FI130328B; CN114599531B

Abstract

Provided is a pneumatic tire in which stud pins are implanted in a tread surface of a tread part, the pneumatic tire being capable of suppressing road surface damage while improving performance on ice. In a pneumatic tire in which stud pins P are implanted in a tread surface of a tread part 1, when band-shaped regions A, each defined between a pair of tire meridians provided so that an interval therebetween along a tire equator CL is 0.8% of the tire circumference, are arranged over the total tire circumference along a tire circumferential direction and at angles shifted one degree at a time, a plurality of the band-shaped regions A include a concentrated region A' having four or more stud pins and a dotted region a having three or fewer stud pins, and in the plurality of band-shaped regions A, a plurality of the concentrated regions A' are present intermittently along the tire circumferential direction.

Description

Pneumatic tires

The present invention relates to a pneumatic tire in which a stud pin is planted on the tread of a tread portion.

In severe winter areas such as Scandinavia and Russia, studless tires are mainly used as winter tires. In the stud tire, a plurality of implantation holes for implanting the stud pins are provided in the tread portion, and the stud pins are implanted in these implantation holes (see, for example, Patent Document 1). Such a stud pin is a factor for improving the running performance on an icy and snowy road surface, but may cause road surface damage when traveling on a road surface other than the icy and snowy road surface (general paved road surface). And even in the winter of the severe winter area, there is an opportunity to drive on paved roads other than ice and snow roads at a considerable frequency. Therefore, in stud tires, measures are required to suppress road surface damage while effectively exhibiting running performance (particularly, traction performance on ice) on ice and snow road surfaces.

Japanese Patent Application Laid-Open No. 2018-187960

An object of the present invention is to provide a pneumatic tire in which a stud pin is planted on the tread of a tread portion, which makes it possible to suppress road surface damage while improving on-ice performance.

The pneumatic tire of the present invention that achieves the above object has a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a tire of these sidewall portions. In a pneumatic tire having a pair of bead portions arranged radially inside and stud pins planted on the tread of the tread portion, the distance on the tire equatorial line is 0.8% of the tire circumference. When a region partitioned between a pair of arranged tire meridional lines is defined as a band-shaped region, and a plurality of strip-shaped regions are arranged over the entire circumference of the tire by shifting the angle by 1 degree along the tire circumferential direction, the plurality of strip-shaped regions are described. The strip-shaped region includes a concentrated region in which the number of stud pins included in the strip-shaped region is 4 or more, and a scattered region in which the number of stud pins included in the strip-shaped region is 3 or less. It is characterized in that a plurality of the concentrated regions are intermittently present along the tire circumferential direction in the plurality of strip-shaped regions.

In the present invention, by providing the stud pin as described above, it is possible to suppress road surface damage while effectively improving the performance on ice. Specifically, since the number of stud pins is large in the concentrated area, the traction performance on ice can be improved, and in the scattered area, the number of stud pins is small, so that road surface damage can be suppressed. Since these concentrated regions and scattered regions coexist in the tire circumferential direction and the concentrated regions exist intermittently, road surface damage can be effectively suppressed without impairing the traction performance on ice.

In the present invention, the total number of stud pins is preferably 135 to 250. By providing an appropriate number of stud pins in this way, it is advantageous to suppress road surface damage while effectively exhibiting traction performance on ice.

In the present invention, it is preferable that the distance between the concentrated regions adjacent to each other in the tire peripheral direction is 1.0% to 30.0% of the tire peripheral length. As a result, when the concentrated areas are provided intermittently, the concentrated areas are present on the tire circumference at appropriate intervals, which is advantageous for suppressing road surface damage while effectively exerting traction performance on ice. ..

In the present invention, it is preferable that there are 3 to 7 dense regions in which the number of stud pins is 5 or more in the plurality of concentrated regions. Since the dense area is particularly excellent in traction performance on ice among the concentrated areas, it is possible to further improve the traction performance on ice. On the other hand, since the number of dense regions is limited to 3 to 7, road surface damage can be sufficiently suppressed even if the dense regions are provided.

At this time, it is preferable that the distance between the dense regions adjacent to each other in the tire peripheral direction is 5.0% to 60.0% of the tire peripheral length. As a result, the dense regions are present on the tire circumference at appropriate intervals, which is advantageous in suppressing road surface damage while effectively exhibiting traction performance on ice.

In the present invention, it is preferable that the average protrusion amount Px of the stud pins included in the concentrated region and the average protrusion amount Pav of the stud pins included in the scattered region satisfy the relationship of Px ≦ 0.9 × Pav. By setting the protruding amount of the stud pins in this way, the protruding amount of the stud pins can be suppressed to a low level in a concentrated region where the number of stud pins is relatively large, which is advantageous in suppressing road surface damage. It is also possible to improve the riding comfort.

In the present invention, the "ground contact end" is the tire axial direction of the ground contact region formed when a tire is rim-assembled on a regular rim, placed vertically on a flat surface with a regular internal pressure applied, and a regular load is applied. Both ends of. A "regular rim" is a rim defined for each tire in a standard system including a standard on which a tire is based. For example, a standard rim for JATTA, a "Design Rim" for TRA, or an ETRTO. If so, use "Measuring Rim". "Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. If it is JATTA, it is the maximum air pressure, and if it is TRA, it is the table "TIRE LOAD LIMITED AT VARIOUS". The maximum value described in "COLD INFLATION PRESSURES", if it is ETRTO, it is "INFRATION PRESSURE", but if the tire is for a passenger car, it is 250 kPa. "Regular load" is the load defined for each tire in the standard system including the standard on which the tire is based. If it is JATTA, it is the maximum load capacity, and if it is TRA, it is the table "TIRE LOAD LIMITED AT VARIOUS". The maximum value described in "COLD INFLATION PRESSURES" is "LOAD CAPACITY" in the case of ETRTO, but when the tire is for a passenger car, the load is equivalent to 80% of the above load.

FIG. 1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a front view showing a tread surface of a pneumatic tire according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing an example of a stud pin planted in a tread portion. FIG. 4 is an explanatory diagram schematically showing a change in the number of stud pins for each strip-shaped region.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the pneumatic tire of the present invention is arranged inside the tread portion 1, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and the sidewall portion 2 in the tire radial direction. It is provided with a pair of bead portions 3. In FIG. 1, reference numeral CL indicates a tire equator, and reference numeral E indicates a ground contact end. Although FIG. 1 is a cross-sectional view of the meridian, the tread portion 1, the sidewall portion 2, and the bead portion 3 each extend in the tire circumferential direction to form an annular shape, whereby the pneumatic tire is formed. The toroidal basic structure of is constructed. Hereinafter, the description using FIG. 1 is basically based on the illustrated meridian cross-sectional shape, but each tire component extends in the tire circumferential direction to form an annular shape.

A carcass layer 4 is mounted between the pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inside to the outside of the vehicle around the bead cores 5 arranged in each bead portion 3. Further, a bead filler 6 is arranged on the outer periphery of the bead core 5, and the bead filler 6 is wrapped by a main body portion and a folded portion of the carcass layer 4. On the other hand, a plurality of layers (two layers in FIG. 1) of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to intersect each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in the range of, for example, 10 ° to 40 °. Further, a belt reinforcing layer 8 is provided on the outer peripheral side of the belt layer 7. The belt reinforcing layer 8 contains an organic fiber cord oriented in the tire circumferential direction. In the belt reinforcing layer 8, the angle of the organic fiber cord with respect to the tire circumferential direction is set to, for example, 0 ° to 5 °.

The present invention is applied to a pneumatic tire having such a general cross-sectional structure, but the basic structure thereof is not limited to the above. Further, since the present invention relates to the arrangement of the stud pin P in the pneumatic tire in which the stud pin P is planted on the tread surface of the tread portion 1, the structure of the groove and the land portion formed on the surface of the tread portion 1 (Tread pattern) is not particularly limited.

The pneumatic tire shown in FIG. 2 has a plurality of lug grooves 11 extending along the tire width direction and a plurality of circumferential grooves 12 extending along the tire circumferential direction. The portion 13 has a partitioned tread pattern. In the illustrated example, the lug groove 11 extends inclined with respect to the tire width direction, one end is located on the tire equatorial CL, and the other end extends beyond the ground contact end E on one side in the tire width direction. The existing first lug groove 11a extends at an angle with respect to the tire width direction, one end is located on the tire equatorial CL, and the other end extends beyond the contact end E on the other side in the tire width direction. The second lug groove 11b is included. In the first lug groove 11a and the second lug groove 11b, one end of the first lug groove 11a and one end of the second lug groove 11b are alternately arranged in the tire circumferential direction on the tire equator CL, and the first lug groove 11a and the second lug groove 11b are arranged in the tire circumferential direction. The 11a and the second lug groove 11b are arranged so as to form a substantially V shape. The circumferential groove 12 extends so as to be inclined with respect to the tire circumferential direction so as to connect the adjacent lug grooves 11 in the tire circumferential direction in the middle portion of each lug groove 11 in the length direction. The center land portion 13a is partitioned inside the tire width direction of the circumferential groove 12, and the shoulder land portion 13b (shoulder block) is partitioned outside the tire width direction of the circumferential groove 12. Further, in the illustrated example, one end communicates with the circumferential groove 12 in the middle portion in the length direction of each circumferential groove 12, extends from the circumferential groove 12 toward the tire equator CL side, and the other end ends. An auxiliary groove 14 is provided that terminates within the center land portion 13a. Further, each land portion 13 is provided with a plurality of sipes 14. The stud pin P can be planted on any land portion 13.

The stud pin P is planted in the stud pin implantation hole provided on the tread surface of the tread portion 1. The stud pin P is planted by inserting the stud pin P into the hole with the planting hole expanded and then releasing the expansion of the planting hole. FIG. 3 is a cross-sectional view schematically showing a state in which the stud pin P is planted in the implantation hole of the tread portion 1. In the illustrated example, the double flange type stud pin P is described as the stud pin P, but a stud pin P having a different structure such as a single flange type can also be used.

As illustrated in FIG. 3, the stud pin P is composed of a columnar body portion P1, a tread side flange portion P2, a bottom side flange portion P3, and a tip portion P4. The tread side flange portion P2 and the bottom side flange portion P3 have a larger diameter than the body portion P1, and the tread side flange portion P2 is formed on the tread surface side (outside in the tire radial direction) of the body portion P1 and the bottom side flange portion. P3 is formed on the bottom side (inside in the tire radial direction) of the body portion P1. The tip portion P4 protrudes outward in the tire radial direction from the tread side flange portion P2 on the pin shaft (center of the stud pin P). Since the tip portion P4 protrudes from the tread surface in a state where the stud pin P is planted in the tread portion 1, it can bite into the ice and snow road surface and exhibits traction on ice. The tip portion P4 is made of a material (for example, a tungsten compound) that is harder than other portions (body portion P1, tread side flange portion P2, bottom side flange portion P3) made of, for example, aluminum or the like. In the present invention, the number of stud pins P included in the strip-shaped region described later is defined, but if at least a part of the tip portion P4 is present in the strip-shaped region described later, the number is counted as the number included in the strip-shaped region. To do.

In the present invention, it is partitioned between a pair of tire meridians arranged so that the distance on the tire equator CL is 0.8% of the tire circumference, regardless of the tread pattern formed on the surface of the tread portion 1. The area is defined as a band-shaped area A (see, for example, the shaded area in FIG. 2). Then, as schematically shown in FIG. 4, a plurality of strip-shaped regions A (A1, A2, A3 ...) Are arranged over the entire circumference of the tire by shifting the angles by 1 degree along the tire circumferential direction. The number of stud pins P included in each band-shaped region A (A1, A2, A3 ...) Is measured. Note that FIG. 4 schematically shows the arrangement of the band-shaped region A, and the details of the tread pattern formed in the tread portion 1 and the specific arrangement of the stud pins P are omitted. Further, the strip-shaped region A after the reference numeral A3 is omitted. The reference numeral R in the figure represents the tire circumferential direction.

Of the plurality of strip-shaped regions A defined in this way, the region in which the number of stud pins included in the strip-shaped region A is 4 or more is the concentrated region A', and the stud pins included in the strip-shaped region A. Assuming that the region where the number of tires is 3 or less is the scattered region a, in the present invention, these concentrated regions A'and the scattered regions a are provided in a mixed manner in the tire circumferential direction. In other words, a plurality of concentrated regions A'are intermittently present along the tire circumferential direction in the plurality of strip-shaped regions A. Since the concentration region A'has a large number of stud pins P, the traction performance on ice can be improved. Since the number of stud pins P is small in the scattered region a, road surface damage can be suppressed. Therefore, these concentrated regions A'and scattered regions a coexist in the tire circumferential direction, and the concentrated regions A'are intermittently present, so that road surface damage can be effectively suppressed without impairing the traction performance on ice. ..

Further, among the plurality of concentrated regions A', if the region in which the number of stud pins is 5 or more is distinguished as the dense region A ", it is preferable that the dense regions A" exist at 3 to 7 locations. Since the dense area A "is particularly excellent in traction performance on ice among the concentrated areas A', it is possible to further improve the traction performance on ice. On the other hand, the number of dense areas A" is reduced to 3 to 7 locations. Since it is suppressed, road surface damage can be sufficiently suppressed even if the dense area A "is provided. If the number of the dense areas A" is less than three, the effect of improving the traction performance on ice becomes insufficient. .. If the number of dense areas A "exceeds seven, road surface damage cannot be sufficiently suppressed.

As in the example of FIG. 2, when the tread portion 1 is provided with three rows of land portions including a center land portion 13a and a pair of shoulder land portions 13b, a concentrated region A ′ in which four or more stud pins are provided. In a dense area A "where 5 or more stud pins are provided, it is preferable to provide at least one stud pin in each land portion. Similarly, the tread portion 1 is provided with, for example, 5 rows of land portions (center land portion and the center land portion). , A pair of shoulder land areas and a middle land area partitioned between the center land area and the shoulder land area), each land area in the dense area A ″ where five or more stud pins are provided. Is preferably provided with at least one stud pin.

The stud pins P may be arranged as described above, but the total number of stud pins in the entire tire is preferably 135 to 250, more preferably 135 to 200. By providing an appropriate number of stud pins P on the entire tire in this way, it is advantageous to suppress road surface damage while effectively exhibiting traction performance on ice. If the total number of stud pins is less than 135, the traction performance on ice cannot be sufficiently improved. If the total number of stud pins exceeds 250, road surface damage cannot be sufficiently suppressed.

In arranging the concentrated regions A'intermittently as described above, it is preferable that the distance L1 between the concentrated regions A'adjacent in the tire peripheral direction is 1.0% to 30.0% of the tire peripheral length. With such an arrangement, the concentrated regions A'are present on the tire circumference at appropriate intervals, which is advantageous in suppressing road surface damage while effectively exhibiting traction performance on ice. If the distance L1 between the concentrated regions A'adjacent to each other in the tire peripheral direction is less than 1.0% of the tire peripheral length, the concentrated regions A'are arranged close to each other in the tire peripheral direction, so that the road surface damage is sufficient. It cannot be suppressed. If the distance L1 between the concentrated regions A'adjacent in the tire circumferential direction exceeds 30.0% of the tire peripheral length, there is a risk that the concentrated region A'will not sufficiently exist in the ground contact surface, and the traction performance on ice will be sufficient. It becomes difficult to secure it. The distance L1 between the concentrated regions A'is, as illustrated in FIG. 2, a length along the tire circumferential direction between the adjacent tire meridians between the adjacent concentrated regions A'. Since the dense region A ″ also corresponds to the concentrated region A ′, the distance between the dense region A ″ and the concentrated region A ′ is shown as the distance L1 between the concentrated regions A ′ in FIG.

Further, it is preferable that the distance L2 between the dense regions A "adjacent to each other in the tire peripheral direction is 5.0% to 60.0% of the tire peripheral length. Therefore, the dense region A" is appropriate on the tire circumference. Since it exists at intervals, it is advantageous in suppressing road surface damage while effectively exerting traction performance on ice. If the distance L2 between adjacent dense areas A ″ in the tire circumferential direction is less than 5.0% of the tire circumference, the dense areas A ″ are arranged close to each other in the tire circumferential direction, so that road surface damage is sufficient. It cannot be suppressed. If the distance L2 between adjacent dense areas A in the tire circumferential direction exceeds 60.0% of the tire circumference, there is a risk that the dense area A ″ will not sufficiently exist in the ground contact surface, and the traction performance on ice will be sufficient. It becomes difficult to secure it. The dense region A "distance L2 (not shown)" is the same as the above-mentioned concentration region A'distance L1 along the tire circumferential direction between the adjacent tire meridians between the adjacent dense regions A ". The length.

The protrusion amount h of the stud pin may be uniform, but the average value of the protrusion amount h of the stud pin included in the concentrated region A'is the average protrusion amount Px, and the protrusion amount h of the stud pin included in the scattered region a. When the average value of is taken as the average protrusion amount Pav, it is preferable that these satisfy the relationship of Px ≦ 0.9 × Pav. By setting the protrusion amount h of the stud pins in this way, the protrusion amount of the stud pins can be suppressed to a low level in the concentrated region A'in which the number of stud pins is relatively large, which is advantageous for suppressing road surface damage. Become. It is also possible to improve the riding comfort. Further, from the viewpoint of ensuring the traction performance on ice, it is preferable to satisfy the relationship of Px ≧ 0.7 × Pav.

Hereinafter, the present invention will be further described with reference to Examples, but the scope of the present invention is not limited to these Examples.

The tire size is 205 / 55R16 94T, it has the basic structure illustrated in FIG. 1, and based on the tread pattern of FIG. 2, the maximum number of stud pins included in the dense area, the number of concentrated areas, and the dense area. Number of tires, total number of stud pins, spacing between concentrated areas adjacent to each other in the tire circumferential direction (minimum value and maximum value), spacing between dense areas adjacent to each other in the tire circumferential direction (minimum value and maximum value), scattered areas The ratio Px / Pav of the average protrusion amount Px of the stud pins included in the concentrated region to the average protrusion amount Pav of the included stud pins is set as shown in Table 1, respectively. Eight 11 types of pneumatic tires were produced.

Since the tire circumference of the pneumatic tire of the above size is 1980 mm, the length of the band-shaped region in the tire circumference direction (0.8% of the tire circumference) is 15.8 mm.

For these pneumatic tires, the stability performance on ice, braking performance on ice, and road surface damage suppression performance were evaluated by the following evaluation methods, and the results are also shown in Table 1.

Stability on ice Steering performance Each test tire is assembled to a wheel with a rim size of 16 x 6.5J, filled with the specified air pressure of the vehicle, mounted on a front-wheel drive vehicle with a displacement of 1.4L, and a test course (turning field) consisting of ice and snow road surfaces. A sensory evaluation was performed by a test driver on the steering stability performance at. The evaluation result is shown by an index with the value of Conventional Example 1 as 100. The larger this index value is, the better the stability performance on ice is.

Braking performance on ice Each test tire is assembled on a wheel with a rim size of 16 x 6.5J, filled with the specified air pressure of the vehicle, mounted on a front-wheel drive vehicle with a displacement of 1.4L, and on a test course (straight road) consisting of ice and snow road surfaces. Then, the brake was applied at an initial speed of 25 km / h, and the braking distance from 20 km / h to 5 km / m was measured. The evaluation result is shown by an index in which the value of Conventional Example 1 is 100, using the reciprocal of the measured value. The larger the index value, the shorter the braking distance and the better the braking performance on ice.

Road surface damage suppression performance Each test tire is assembled to a wheel with a rim size of 16 x 6.5J, the air pressure is 250 kPa, it is mounted on a front-wheel drive vehicle with a displacement of 1.4 L, and the speed is 100 km / h on the granite installed on the road surface. The amount of wear was measured by the weight difference of the granite before and after the test, and the amount of road surface wear was measured. The evaluation result is shown by an index with the value of Conventional Example 1 as 100 using the reciprocal of the measured value. The larger the index value, the smaller the amount of road surface wear, which means that the road surface damage suppressing performance is excellent. If the index value is "85" or more, it means that good road surface damage suppression performance has been obtained.

As is clear from Table 1, in each of Examples 1 to 8, the on-ice steering stability performance and the on-ice braking performance were improved, and the road surface damage suppression performance was maintained well as compared with the conventional example 1. On the other hand, in Comparative Examples 1 and 2, since there was only one concentrated area, it was not possible to achieve both improvement of performance on ice and suppression of road surface damage.

1 Tread part 2 Side wall part 3 Bead part 4 Carcus layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt reinforcement layer 11 Rug groove 12 Circumferential groove 13 Land part 14 Auxiliary groove 15 Sipe P Stud pin A Band-shaped area a Dotted area A ′ Concentrated area A ″ Dense area CL Tire equator E Grounding edge

Claims

A tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. In addition, in a pneumatic tire in which a stud pin is planted on the tread of the tread portion,
The area defined between a pair of tire meridians arranged so that the distance on the tire equatorial line is 0.8% of the tire circumference is defined as a band-shaped area, and a plurality of band-shaped areas are angled along the tire circumference direction. When the tires are staggered once and arranged over the entire circumference of the tire,
The plurality of strip-shaped regions include a concentrated region in which the number of stud pins included in the strip-shaped region is 4 or more, and a scattered region in which the number of stud pins included in the strip-shaped region is 3 or less. A pneumatic tire including, wherein a plurality of the concentrated regions are intermittently present along the tire circumferential direction in the plurality of strip-shaped regions.
The pneumatic tire according to claim 1, wherein the total number of the stud pins is 135 to 250.
The pneumatic tire according to claim 1 or 2, wherein the distance between the concentrated regions adjacent to each other in the tire peripheral direction is 1.0% to 30.0% of the tire peripheral length.
The pneumatic tire according to any one of claims 1 to 3, wherein there are 3 to 7 dense regions having 5 or more stud pins in the plurality of concentrated regions.
The pneumatic tire according to claim 4, wherein the distance between the dense regions adjacent to each other in the tire peripheral direction is 5.0% to 60.0% of the tire peripheral length.
The average protrusion amount Px of the stud pins included in the concentrated region and the average protrusion amount Pav of the stud pins included in the scattered region satisfy the relationship of Px ≦ 0.9 × Pav. The pneumatic tire according to any one of claims 1 to 5.