JP7172954B2 - pneumatic tire - Google Patents

Description

The present invention relates to a pneumatic tire in which stud pins are implanted in the tread surface of the tread portion.

Studded tires are mainly used as winter tires in harsh winter regions such as Northern Europe and Russia. In a stud tire, a plurality of implantation holes for implanting stud pins are provided in the tread portion, and the stud pins are implanted in these implantation holes (see Patent Document 1, for example). Such a stud pin exerts an effect of scratching the icy and snowy road surface when the vehicle is driven on the icy and snowy road surface, so that the performance on ice can be improved. On the other hand, when driving on road surfaces other than ice and snow (especially dry paved road surfaces), the impact of the hard stud pins striking the paved road surface is transmitted as a shock sensation, which may deteriorate ride comfort. And even in the winter season of severe winter regions, there is a not infrequent opportunity to travel on a paved road surface (dry road surface) other than an ice-snow road surface. Therefore, stud tires are required to take measures to improve ride comfort performance on dry road surfaces while effectively demonstrating running performance (especially traction performance on ice) on icy and snowy road surfaces.

JP-A-2018-187960

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire in which stud pins are implanted in the tread surface of the tread portion, and which is capable of improving ride comfort performance on dry road surfaces while improving performance on ice. That's what it is.

The pneumatic tire of the present invention for achieving the above object comprises a tread portion extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a tire of these sidewall portions. A pneumatic tire having a pair of bead portions arranged radially inward, and having stud pins implanted in the tread surface of the tread portion, arranged so that the interval on the tire equator line is 1/4 of the tire contact length. A region partitioned between a pair of tire meridians is defined as a band-shaped region, and when a plurality of band-shaped regions are shifted by 1 degree along the tire circumferential direction and arranged over the entire circumference of the tire, the plurality of band-shaped regions In all cases, the number n of stud pins included in each band-shaped region is 4.0% or less of the total number N of stud pins in the entire circumference of the tire, and two-thirds or more of the plurality of band-shaped regions are included in the band-shaped region It is characterized in that the number n of stud pins provided is 2.0% or more of the total number N.

In the present invention, by providing the stud pins as described above, it is possible to effectively improve the on-ice performance while exhibiting excellent ride comfort performance on dry road surfaces. Specifically, in all strip regions, the ratio of the number n of stud pins to the total number N of stud pins is suppressed to 4.0% or less. It is possible to suppress the feeling of shock when driving, and to improve the riding comfort performance. On the other hand, the ratio of the number n of stud pins to the total number N of stud pins is 2.0% or more. can be demonstrated in

In the present invention, the total number of stud pins is preferably 135-250. By providing an appropriate number of stud pins in this manner, it is advantageous to improve ride comfort performance on dry road surfaces while effectively exhibiting performance on ice.

In the present invention, among the plurality of band-shaped regions, there is at least one concentrated region in which the number n of stud pins included in the band-shaped region is 3.0% or more of the total number N, and among the plurality of band-shaped regions is preferably present in 1/3 or less of the In this way, by providing a concentrated area having a large number of stud pins and excellent on-ice performance, it is possible to further improve on-ice performance. On the other hand, since the number of concentrated areas is suppressed to 1/3 or less of the plurality of belt-shaped areas, even if the concentrated areas are provided, it is possible to exhibit excellent ride comfort performance on dry road surfaces.

At this time, in the concentrated area, there are two or more dense areas in which the number n of stud pins included in the belt-like area is 3.5% or more of the total number N, and the dense areas adjacent to each other in the tire circumferential direction are present. is preferably 100% or more of the tire contact length. Since the dense area is particularly excellent in performance on ice among the concentrated areas, it is possible to further improve the performance on ice. On the other hand, since the distance between the dense areas is set to be larger than the tire contact length, the number of dense areas that exist on the contact surface when the tire is rolling is always one or less. The comfortable performance can be exhibited satisfactorily.

Furthermore, it is preferable that the average protrusion amount Px of the stud pins included in the concentrated area and the average protrusion amount Pav of the stud pins in the area excluding the concentrated area satisfy the relationship of Px ≤ 0.9 x Pav. By setting the amount of protrusion of the stud pins in this way, it is possible to keep the amount of protrusion of the stud pins low in the concentrated area where the number of stud pins is relatively large, and to exhibit good ride comfort on dry road surfaces. becomes advantageous.

In the present invention, among the regions obtained by dividing the tread surface of the tread portion into three equal parts in the tire width direction, the region located on the tire equator is defined as the center region, and the pair of regions located on both sides of the center region in the tire width direction are shoulders. As for regions, it is preferable that at least one stud pin is present in each of the center region and the pair of shoulder regions in a band-shaped region where the number n of stud pins is 3 or more. By arranging the stud pins dispersedly in the tire width direction in this way, it is possible to obtain a force for efficiently scraping the snowy and icy road surface over the entire tire width direction, which is advantageous for improving the performance on ice. Also, the uniformity in the tire width direction can be improved.

In the present invention, the term "contact length" refers to the ground contact area on the equator of the tire formed when the tire is mounted on a regular rim, filled with regular internal pressure, placed vertically on a flat surface, and a regular load is applied. is the length in the circumferential direction of the tire. Further, the "grounding edge" is both ends of the grounding area in the axial direction of the tire. "Regular rim" is a rim defined for each tire in a standard system including the standard on which the tire is based. For example, JATMA is a standard rim, TRA is a "Design Rim", or ETRTO. If so, it should be "Measuring Rim". "Normal internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standard on which the tire is based. The maximum value described in "COLD INFLATION PRESSURES", which is "INFLATION PRESSURE" for ETRTO, is 250 kPa when the tire is for a passenger car. "Normal load" is the load defined for each tire by each standard in the standard system including the standard on which the tire is based. "COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO, but if the tire is for a passenger car, the load is set to 80% of the above load.

1 is a meridional cross-sectional view of a pneumatic tire according to an embodiment of the present invention; FIG. 1 is a front view showing a tread surface of a pneumatic tire according to an embodiment of the invention; FIG. FIG. 4 is a cross-sectional view schematically showing an example of a stud pin implanted in a tread portion; FIG. 5 is an explanatory diagram schematically showing changes in the number of stud pins for each band-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 includes a tread portion 1, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of sidewall portions 2 arranged radially inward of the sidewall portions 2. and a pair of bead portions 3. In FIG. 1, symbol CL indicates the tire equator, and symbol E indicates the ground contact edge. Although FIG. 1 is a meridional sectional view and is not depicted, the tread portion 1, the sidewall portion 2, and the bead portion 3 each extend in the tire circumferential direction and form an annular shape. A toroidal basic structure is constructed. The following explanation using FIG. 1 is basically based on the meridian cross-sectional shape shown in the drawing, but each tire constituent member extends in the tire circumferential direction and forms 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 vehicle inner side to the outer side around bead cores 5 arranged in the respective bead portions 3 . A bead filler 6 is arranged on the outer periphery of the bead core 5, and the bead filler 6 is wrapped by the main body portion and the folded portion of the carcass layer 4. - 特許庁On the other hand, a plurality of belt layers 7 (two layers in FIG. 1) are embedded in the outer peripheral side of the carcass layer 4 in the tread portion 1 . Each belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set, for example, in the range of 10° to 40°. Furthermore, a belt reinforcing layer 8 is provided on the outer peripheral side of the belt layer 7 . The belt reinforcing layer 8 contains organic fiber cords oriented in the tire circumferential direction. In the belt reinforcing layer 8, the angle of the organic fiber cords with respect to the tire circumferential direction is set to 0° to 5°, for example.

The present invention is applied to a pneumatic tire having such a general cross-sectional structure, but its basic structure is not limited to the one described above. Further, the present invention relates to the arrangement of stud pins P in a pneumatic tire in which the stud pins P are implanted in the tread surface of the tread portion 1. Therefore, the structure of the grooves and land portions formed on the surface of the tread portion 1 is as follows. (Tread pattern) is not particularly limited.

The pneumatic tire shown in FIG. 2 has a plurality of land grooves formed by 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 segmented tread pattern. In the illustrated example, the lug groove 11 extends obliquely with respect to the tire width direction, one end is positioned on the tire equator CL, and the other end extends beyond the ground contact edge E on one side in the tire width direction. The first lug groove 11a extends obliquely with respect to the tire width direction, one end is positioned on the tire equator CL, and the other end extends beyond the ground contact edge E on the other side in the tire width direction. and the second lug groove 11b. In the first lug grooves 11a and the second lug grooves 11b, one end of the first lug grooves 11a and one end of the second lug grooves 11b are alternately arranged in the tire circumferential direction on the tire equator CL. 11a and the second lug groove 11b are arranged to form a substantially V shape. The circumferential grooves 12 extend obliquely with respect to the tire circumferential direction so as to connect the lug grooves 11 adjacent to each other in the tire circumferential direction at the midpoint of each lug groove 11 in the length direction. A center land portion 13a is defined on the inner side of the circumferential groove 12 in the tire width direction, and a shoulder land portion 13b (shoulder block) is defined on the outer side of the circumferential groove 12 in the tire width direction. Furthermore, in the illustrated example, one end communicates with the circumferential groove 12 in the middle of the length direction of each circumferential groove 12, extends from the circumferential groove 12 toward the tire equator CL side, and the other end An auxiliary groove 14 is provided that terminates within the center land portion 13a. In addition, each land portion 13 is provided with a plurality of sipes 14 . The stud pin P can be implanted in any land portion 13 .

The stud pin P is implanted in a stud pin implant hole provided in the tread surface of the tread portion 1 . The stud pin P is implanted by inserting the stud pin P into the hole with the hole expanded, and then canceling the expansion of the hole. FIG. 3 is a cross-sectional view schematically showing a state in which the stud pin P is implanted in the implant hole of the tread portion 1. As shown in FIG. Although the example of illustration describes the stud pin P of a double flange type as the stud pin P, the stud pin P of another structure, such as a single flange type, can also be used.

As illustrated in FIG. 3, the stud pin P is composed of a cylindrical 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 are larger in diameter than the trunk portion P1, and the tread-side flange portion P2 is formed on the tread-surface side of the trunk portion P1 (outside in the tire radial direction). P3 is formed on the bottom side (inside in the tire radial direction) of body portion P1. The tip portion P4 protrudes outward in the tire radial direction from the tread-side flange portion P2 at the pin axis (the center of the stud pin P). Since the tip portion P4 protrudes from the tread surface while the stud pin P is implanted in the tread portion 1, it can bite into the icy and snowy road surface and exhibits traction on ice. The tip portion P4 is made of a material (for example, a tungsten compound) harder than the other portions (body portion P1, tread side flange portion P2, bottom side flange portion P3) made of aluminum or the like. In the present invention, the number of stud pins P included in a band-like region, which will be described later, is defined. If at least a part of the tip portion P4 exists within the band-like region, it is counted as the number included in the band-like region. do.

In the present invention, regardless of the tread pattern formed on the surface of the tread portion 1, the tire meridian is divided between a pair of tire meridians arranged such that the interval on the tire equator CL is 1/4 of the tire contact length. Define the region as strip A (see, for example, the shaded area in FIG. 2). Then, as schematically shown in FIG. 4, a plurality of band-shaped regions A (A1, A2, A3, . The number n of stud pins P included in area A (A1, A2, A3, . . . ) is measured. 4 schematically shows the arrangement of the band-shaped regions A, and details of the tread pattern formed on the tread portion 1 and the specific arrangement of the stud pins P are omitted. Moreover, the band-shaped area A after the symbol A3 is omitted. Symbol R in the drawing represents the tire circumferential direction.

In all of the strip regions A thus defined, the number n of stud pins P included in each strip region A is set to 4.0% or less of the total number N of stud pins P in the entire circumference of the tire. . For example, in the example shown in FIG. 4, the number n of stud pins P is seven or less. In the example of FIG. 4, the total number N=190 is assumed, and 4.0% of the total number N is 7.6, so the example of FIG. 4 satisfies the above conditions. Also in the example of FIG. 2, if the total number N=190, the number n of stud pins P in the three belt-shaped regions A (shaded areas) surrounded by the dashed-dotted lines is 7 or less, as described above. meet the conditions of On the other hand, in two-thirds or more of the strip regions A, the number n of stud pins P included in the strip region A is set to 2.0% or more of the total number N of stud pins P. For example, when the total number N=190, 2.0% of the total number N is 3.8, so in the example of FIG. If 2/3 or more of the area A is used, the above condition is satisfied. In this manner, in all strip regions A, the ratio of the number n of stud pins P to the total number N of stud pins P is kept low to 4.0% or less. It is possible to suppress the feeling of shock when contacting the road surface, and improve the riding comfort performance. On the other hand, since the band-shaped area A is sufficiently provided around the entire circumference of the tire, the ratio of the number n of the stud pins P to the total number N of the stud pins P is set to a moderate range of 2.0% or more. Good performance can be exhibited.

Further, among the plurality of band-shaped regions A, if a region in which the number n of stud pins P contained in the band-shaped region A is 3.0% or more of the total number N of stud pins P is distinguished as a concentrated region A', this concentrated region A' It is preferable that one or more regions A' exist on the tire circumference. In the example shown in FIG. 4, the total number N=190 is assumed as described above, and 3.0% of the total number N is 5.7. The band-shaped area A in which the stud pins P are provided corresponds to the concentrated area A'. In addition, in the three belt-like regions A (hatched portions) shown in FIG. 2, the locations where the number n of stud pins P is 6 or 7 correspond to concentrated regions A'. In FIG. 2, the location where the number n of the stud pins P is 7 corresponds to a dense area A″, which will be described later. It corresponds to area A'. When a plurality of concentrated areas A' are provided, it is preferable that the concentrated area A' is suppressed to 1/3 or less of the plurality of band-shaped areas A. Since the concentration area A' has more stud pins P than the other strip areas A and is excellent in performance on ice, the provision of such a concentration area A' can further improve the performance on ice. On the other hand, since the number of concentrated areas A' is suppressed to 1/3 or less of the plurality of band-shaped areas A, even if the concentrated areas A' are provided, it is possible to exhibit good ride comfort performance on a dry road surface. . If the number of concentrated areas A' exceeds 1/3 of the plurality of belt-shaped areas A, the number of concentrated areas A' where many stud pins P, which may cause a feeling of shock during running, is increased, resulting in poor riding comfort performance. It becomes difficult to demonstrate well.

Furthermore, among the concentrated areas A', if the number n of stud pins P included in the belt-like area is 3.5% or more of the total number N of stud pins P, the area is classified as a dense area A''. ″ is present at one or more locations on the tire circumference. In the example shown in FIG. 4, the total number N=190 is assumed as described above, and 3.5% of the total number N is 6.7. The band-shaped area A in which the stud pins P are provided corresponds to the concentrated area A'. In addition, in the three belt-shaped areas A (shaded areas) shown in FIG. 2, the area where the number n of the stud pins P is seven corresponds to the concentrated area A″. It is preferable that the interval between the dense regions A'' adjacent in the circumferential direction is 100% or more of the tire contact length. further improvement can be achieved. On the other hand, since the distance between the dense areas A'' is set to be larger than the tire contact length, the number of dense areas A'' that exist within the ground contact surface during tire rolling is reduced to one or less. When the distance between the dense areas A'' is less than 100% of the ground contact length, there are many stud pins P that can cause a feeling of shock during driving. Since a plurality of dense regions A'' may exist in the ground contact surface, it is difficult to exhibit good ride comfort performance. It is the length along the tire circumference between opposing tire meridians.

The stud pins P may be arranged as described above, and the total number of stud pins in the entire tire is preferably 135-250, more preferably 135-200. By providing an appropriate number of stud pins P over the entire tire in this manner, it is advantageous to effectively exhibit performance on ice while exhibiting good ride comfort performance. 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, the riding comfort performance cannot be sufficiently exhibited.

As shown in FIG. 2, among the regions obtained by dividing the tread surface of the tread portion 1 (the range between the ground contact edges E on both sides in the tire width direction) into three equal parts in the tire width direction, the region located on the tire equator CL is the center region. Ce and a pair of regions located on both sides of the center region Ce in the tire width direction are shoulder regions Sh. At least one stud pin P is preferably present in each region Sh. By arranging the stud pins dispersedly in the tire width direction in this way, it is possible to obtain a force for efficiently scraping the snowy and icy road surface over the entire tire width direction, which is advantageous for improving the performance on ice. Also, the uniformity in the tire width direction can be improved. For example, when the total number N of stud pins P is 135, the number n of stud pins P is 3 or more in the band-shaped area A where the number n of stud pins P is 2.0% or more of the total number N ( 135 x 0.020 = 2.7). In this case, if the stud pins P are dispersedly arranged as described above, at least one stud pin P is provided in each of the center region Ce and the pair of shoulder regions Sh in two-thirds or more of the plurality of band-shaped regions A. They will be distributed. Therefore, it is very effective for improving on-ice performance.

The amount of protrusion h of the stud pins P may be uniform, but the average value of the amount of protrusion h of the stud pins P included in the concentrated area A' is defined as the average amount of protrusion Px. When the average value of the protrusion amount h of the stud pin P is defined as the average protrusion amount Pav, it is preferable that these satisfy the relationship of Px ≤ 0.9 x Pav. By setting the amount h of protrusion of the stud pin P in this way, the amount of protrusion of the stud pin can be kept low in the concentrated area A' where the number of stud pins is relatively large. be advantageous. Furthermore, from the viewpoint of ensuring sufficient on-ice performance, it is preferable to satisfy the relationship Px ≥ 0.7 x Pav.

EXAMPLES The present invention will be further described with reference to examples below, but the scope of the present invention is not limited to these examples.

The tire size is 205/55R16 94T, has the basic structure illustrated in FIG. 1, is based on the tread pattern of FIG. Eleven types of pneumatic tires of Examples 1 to 8 were produced.

In Table 1, "total number N" is the total number of stud pins provided in the entire tire, and "n" is the number of stud pins included in each dense area. Regarding the "maximum value of n in the band-shaped area", the condition of the upper limit value defined in the present invention (4.0% of the total number N = 0.04N), the measured value for each tire, and the magnitude relationship between them are displayed. did. In particular, regarding the magnitude relationship, the case where the measured value is equal to or less than the upper limit condition (0.04N) is indicated by "o", and the case where the measured value exceeds the upper limit condition (0.04N) is indicated by "x". The "standard arrangement area" means a band-shaped area satisfying the condition that the number n of stud pins is 2.0% or more of the total number N of stud pins. Regarding this "standard placement area", the conditions of the lower limit defined in the present invention (2.0% of the total number N = 0.02N), the presence or absence of the standard placement area, and the ratio of the standard placement area to the total strip area was displayed. As for the "concentrated area", the condition of the lower limit value defined in the present invention (3.0% of the total number N=0.03N), the presence or absence of the concentrated area, and the ratio of the concentrated area to the total belt-shaped area are displayed. Regarding the "dense area", the condition of the lower limit value defined in the present invention (3.5% of the total number N = 0.035N), the presence or absence of the dense area, and the minimum interval between the dense areas adjacent to each other in the tire circumferential direction (Percentage to contact length) is displayed. "Arrangement of stud pins in the width direction" means the arrangement of stud pins in the tire width direction in a band-shaped region in which the number of studs n is 3 or more, and at least one stud is provided in each of the center region and the pair of shoulder regions. The presence of pins was indicated as "distributed", and the case of absence of stud pins in either the center region or the pair of shoulder regions was indicated as "unevenly distributed". "Px/Pav" is the ratio of the average protrusion amount Px of the stud pins included in the concentration area to the average protrusion amount Pav of the stud pins provided in the area excluding the concentration area.

The 11 types of pneumatic tires described above (conventional example 1, comparative examples 1 to 2, and examples 1 to 8) had a common contact length of 120 mm. That is, in each example, the circumferential length of the belt-like region (1/4 of the tire contact length) is 30 mm.

These pneumatic tires were evaluated for steering stability on ice, ride comfort on dry road surfaces, and low vibration performance on dry road surfaces by the following evaluation methods. Table 1 also shows the results.

Steady performance on ice Each test tire was mounted on a wheel with a rim size of 16 x 6.5J, inflated to the specified air pressure for the vehicle, and mounted on a front-wheel drive vehicle with a displacement of 1.4L. A sensory evaluation was performed by a test driver on the steering stability performance. The evaluation results are shown as indices with the value of Conventional Example 1 being 100. It means that the larger the index value, the better the steering stability performance on ice.

Riding comfort performance on dry road surface Each test tire was mounted on a wheel with a rim size of 16 x 6.5J, inflated to the designated air pressure for the vehicle, mounted on a 1.4-liter front-wheel drive vehicle, and tested on a dry road test course. , Riding comfort performance (shock feeling) was sensory evaluated by a test driver. The evaluation results are shown as indices with the value of Conventional Example 1 being 100. The larger the index value, the smaller the shock feeling and the better the ride comfort performance on dry road surfaces.

Low vibration performance on dry road surface Each test tire was mounted on a wheel with a rim size of 16 x 6.5J, inflated to the specified air pressure for the vehicle, mounted on a 1.4-liter front-wheel drive vehicle, and tested on a dry road test course. , sensory evaluation of vibration was performed. The evaluation results are shown as indices with the value of Conventional Example 1 being 100. The larger the index value, the smaller the vibration, which means excellent low-vibration performance on dry road surfaces. It should be noted that the better the low vibration performance, the better the weight balance of the tire and the better the uniformity.

As is clear from Table 1, all of Examples 1 to 8, compared to Conventional Example 1, demonstrate good steering stability performance on ice, while also exhibiting good ride comfort performance and low vibration performance on dry road surfaces. and achieved a high degree of compatibility between these performances. On the other hand, in Comparative Example 1, since there were few band-shaped regions satisfying the condition that the number n of stud pins was 2.0% or more of the total number N of stud pins, the steering stability performance on ice deteriorated. Since Comparative Example 2 has a band-like region in which the number of stud pins is more than 4.0% of the total number N, the ride comfort performance and low vibration performance on a dry road surface are deteriorated.

1 Tread Part 2 Side Wall Part 3 Bead Part 4 Carcass Layer 5 Bead Core 6 Bead Filler 7 Belt Layer 8 Belt Reinforcing Layer 11 Lug Groove 12 Circumferential Groove 13 Land Part 14 Auxiliary Groove 15 Sipe P Stud Pin A Strip Region A' Concentration Region A″ Dense area Ce Center area Sh Shoulder area CL Tire equator E Ground contact edge

Claims (6)

A tread portion extending in the tire circumferential direction and forming 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 the sidewall portions. In a pneumatic tire in which a stud pin is implanted in the tread surface of the tread portion,
A region defined between a pair of tire meridians arranged so that the interval on the tire equator line is 1/4 of the tire contact length is defined as a band-shaped region, and each of the plurality of band-shaped regions is 1 degree along the tire circumferential direction. When staggered and arranged over the entire circumference of the tire,
The number n of stud pins included in each strip-shaped region in all of the plurality of strip-shaped regions is 4.0% or less of the total number N of stud pins in the entire circumference of the tire, and 2/3 or more of the plurality of strip-shaped regions 2. A pneumatic tire according to claim 1, wherein the number n of stud pins included in said belt-like region is 2.0% or more of said total number N. 2. The pneumatic tire according to claim 1, wherein the total number of said stud pins is 135-250. Among the plurality of band-shaped regions, there is at least one concentrated region in which the number n of stud pins included in the band-shaped region is 3.0% or more of the total number N, and one of the plurality of band-shaped regions 3. The pneumatic tire according to claim 1 or 2, characterized in that it exists at /3 or less. In the concentrated area, there are two or more dense areas in which the number n of stud pins included in the belt-like area is 3.5% or more of the total number N, and the dense areas adjacent to each other in the tire circumferential direction are separated from each other. 4. The pneumatic tire according to claim 3, wherein the interval is 100% or more of the tire contact length. An average protrusion amount Px of the stud pins included in the concentrated area and an average protrusion amount Pav of the stud pins in the area excluding the concentrated area satisfy a relationship of Px ≤ 0.9 x Pav. The pneumatic tire according to any one of claims 1 to 4. Of the regions obtained by dividing the tread surface of the tread portion into three equal parts in the tire width direction, a region located on the tire equator is defined as a center region, and a pair of regions located on both sides of the center region in the tire width direction are defined as shoulder regions. At least one stud pin is present in each of the center region and the pair of shoulder regions in the band-shaped region where the number n of stud pins is 3 or more. The pneumatic tire described in

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