JP2020044863A - Pneumatic tires and stud tires - Google Patents

Abstract

To improve braking/driving performance of a pneumatic tire with stud pins on icy roads.SOLUTION: A tread part of a pneumatic tire has a plurality of stud pin mounting holes, and a pair of recesses that are recessed inward in a tire radial direction in a hole peripheral region on a surface of the tread part around the stud pin mounting holes. The recesses are arranged on both sides of the stud pin mounting hole in a tire circumferential direction, and extend linearly. When the surface of the tread part is viewed in a direction perpendicular to the surface, a shape of the recess is a shape protruding toward a side approaching the stud pin mounting hole, or a linear shape crossing a straight line parallel to the tire circumferential direction. The tread part further has a pair of protrusions projecting outward in a tire radial direction in the hole peripheral region. The protrusion is disposed farther from the stud pin mounting hole than the recess, and linearly extends along the recess.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pneumatic tire to which a stud pin is mounted, and a stud tire.

  A stud tire (spike tire) in which a stud pin is mounted in a stud pin mounting hole provided in a tread portion has been known as a tire having improved running performance on an icy and snowy road surface.

  In recent years, in the area of the tread surface around the stud pin mounting hole (hole peripheral area), a concave portion recessed inward in the tire radial direction is provided, and the ice powder shaved by the stud pin is stored in the concave portion, so that the ice powder can be removed. It is becoming a trend to prevent the stud pins from scratching the road surface and to maintain the stud pin's scratching effect.

  For example, in the tire described in Patent Literature 1, a stud hole for embedding a spike pin is formed on the tread of the tread portion, and a recess is formed around the stud hole.

JP 2013-180584 A

  However, if there is snow or ice debris on the icy road surface, the snow or the like may enter the recess during braking, and the ice powder shaved by the stud pin may not be accommodated in the recess. For this reason, there is a problem that the ice powder not stored in the recess inhibits the stud pins from scratching the road surface, and the braking / driving performance on the road surface on ice is reduced.

  Accordingly, an object of the present invention is to improve the braking / driving performance on an icy road surface in a pneumatic tire and a stud tire to which a stud pin is mounted.

One embodiment of the present invention is a pneumatic tire,
Equipped with an annular tread in the tire circumferential direction,
The tread portion,
A plurality of stud pin mounting holes to which stud pins are mounted,
A pair of recesses recessed inward in the tire radial direction in a hole peripheral region on the surface of the tread portion around at least one stud pin mounting hole of the stud pin mounting holes,
The recess is disposed on both sides of the at least one stud pin mounting hole in the tire circumferential direction, extends linearly,
When the surface of the tread portion is viewed in a direction perpendicular to the surface, the shape of the recess is a shape protruding toward the side approaching the at least one stud pin mounting hole, or a straight line parallel to the tire circumferential direction. It is a straight line that traverses,
The tread portion further has a pair of convex portions projecting outward in the tire radial direction in the hole peripheral region,
The convex portion is disposed farther from the stud pin mounting hole than the concave portion, and extends linearly along the concave portion.
It is preferable that the arrangement range of the concave portion along the tire width direction includes the arrangement range of the at least one stud pin mounting hole along the tire width direction. In addition, it is preferable that the arrangement range of the projection along the tire width direction includes the arrangement range of the at least one stud pin mounting hole along the tire width direction.
It is preferable that the linear shape is a shape crossing a straight line parallel to the tire circumferential direction passing through the at least one stud pin mounting hole.

  Preferably, the protruding shape is an arc shape.

  It is preferable that the concave depth of the concave portion is longer than the projecting height of the convex portion.

  It is preferable that the projecting height of the projection is lower than the height of the stud pins attached to the at least one stud pin attaching hole projecting from the stud pin attaching hole.

The protrusion has a distribution of protrusion heights along the extending direction,
It is preferable that the protruding height is the highest at the center between both ends in the extending direction of the projection.

The protrusion has a width distribution along the extending direction,
It is preferable that the width of the projection is the largest at the center between both ends in the extending direction of the projection.

The recess has a distribution of recess depth along the extending direction,
The depth of the recess is preferably the deepest at the center between both ends in the extending direction of the recess.

The recess has a width distribution along the extending direction,
It is preferable that the width of the concave portion is the largest at the center between both ends in the extending direction of the concave portion.

  It is preferable that a prospective angle of the concave portion and the convex portion as viewed from the center of the cross section of the at least one stud pin mounting hole along the surface of the tread portion is 60 degrees or more.

The ground area of the tread portion,
A center area located within a range of not more than 25% of the contact width on both sides in the tire width direction from the tire center line;
A shoulder region located outside the center region in the tire width direction,
The at least one stud pin mounting hole is provided in the center region and the shoulder region,
It is preferable that the expected angles of the concave portion and the convex portion are wider in the shoulder region than in the center region.

  It is preferable that the maximum distance between the concave portion and the convex portion located on the same side in the tire circumferential direction with respect to the at least one stud pin mounting hole is not more than twice the width of the concave portion.

The rotation direction of the pneumatic tire is specified,
Among the recesses, a first recess located on a side opposite to the rotation direction with respect to the at least one stud pin mounting hole is compared with a second recess located on the rotation direction side in the first recess. It is preferable that the maximum width of the concave portion is large or the maximum concave depth is deep.

  It is preferable that a minimum distance between the at least one stud pin mounting hole and the concave portion exceeds 1 mm.

Another embodiment of the present invention is a stud tire,
The pneumatic tire,
And a stud pin attached to a stud pin attachment hole of the pneumatic tire.

  According to the above aspect, in the pneumatic tire and the stud tire to which the stud pin is mounted, the braking / driving performance on an icy road surface is improved.

It is a tire sectional view showing a section of a pneumatic tire of this embodiment. FIG. 2 is a diagram illustrating an example of a tread pattern applied to the pneumatic tire of FIG. 1. It is a figure showing an example of a stud pin attached to a pneumatic tire. It is a top view which shows a recessed part and a convex part. FIG. 5 is a view taken along line VV of FIG. 4. (A) is a figure explaining operation of a pneumatic tire of a comparative example, and (b) is a figure explaining operation of a pneumatic tire of this embodiment. It is a figure explaining an operation of a pneumatic tire of this embodiment. It is a top view which shows the modification of a recessed part and a convex part. It is a figure showing an example of distribution of projection height of a convex part. It is a figure showing an example of distribution of the width of a convex part. It is a figure showing an example of distribution of dent depth of a crevice. It is a figure showing an example of distribution of the width of a crevice. It is a top view explaining the prospective angle of a concave part and a convex part. It is a top view explaining the space | interval of a recessed part and a convex part.

Hereinafter, the pneumatic tire and the stud tire of the present embodiment will be described in detail. This embodiment includes various embodiments described later.
(Overall description of tires)
FIG. 1 is a tire cross-sectional view showing a cross section of a pneumatic tire (hereinafter, referred to as a tire) 10 of the present embodiment cut along a tire radial direction. The tire 10 is a stud tire having a stud pin embedded in a tread portion.
The tire 10 is, for example, a passenger car tire. Passenger car tires are tires defined in Chapter A of JATMA YEAR BOOK 2015 (Japan Automobile Tire Association Standard). In addition, the present invention can be applied to light truck tires defined in Chapter B and truck and bus tires defined in Chapter C.

  The tire circumferential direction described hereinafter refers to the direction in which the tread surface rotates when the tire 10 is rotated about the tire rotation axis (both rotation directions), and the tire radial direction refers to the tire rotation axis. It refers to a radiation direction that extends orthogonally. The outer side in the tire radial direction refers to a side away from the tire rotational axis in the tire radial direction, and the inner side in the tire radial direction refers to a side approaching the tire rotational axis in the tire radial direction. The tire width direction refers to a direction parallel to the direction of the tire rotation axis, and the tire width direction outside refers to both sides of the tire 10 away from the tire center line CL. The inner side in the tire width direction refers to a side approaching the tire center line CL of the tire 10 in the tire width direction.

(Tire structure)
The tire 10 has a carcass ply layer 12, a belt layer 14, and a bead core 16 as a skeleton material or a skeleton material layer, and around these skeleton materials, a tread rubber member 18, a side rubber member 20, It mainly has a bead filler rubber member 22, a rim cushion rubber member 24, and an inner liner rubber member 26.

  The carcass ply layer 12 includes carcass ply materials 12a and 12b formed by winding organic fibers with rubber to form a toroidal shape by winding between a pair of annular bead cores 16. In the tire 10 shown in FIG. 1, the carcass ply layer 12 is constituted by the carcass ply materials 12a and 12b, but may be constituted by one carcass ply material. A belt layer 14 composed of two belt members 14a and 14b is provided outside the carcass ply layer 12 in the tire radial direction. The belt layer 14 is a member in which rubber is coated on a steel cord arranged at a predetermined angle, for example, 20 to 30 degrees, with respect to the tire circumferential direction, and the lower belt material 14a is replaced with the upper belt material 14b. The width in the tire width direction is wider than that. The inclination directions of the steel cords of the two layers of belt members 14a and 14b are opposite to each other. For this reason, the belt members 14a and 14b are interlaced layers and suppress the expansion of the carcass ply layer 12 due to the filled air pressure.

A tread rubber member 18 is provided outside the belt layer 14 in the tire radial direction, and side rubber members 20 are connected to both ends of the tread rubber member 18 to form a sidewall portion. The tread rubber member 18 is composed of two layers of rubber members, and has an upper tread rubber member 18a provided on the tire radial outside and a lower tread rubber member 18b provided on the tire radial inside. A rim cushion rubber member 24 is provided at an inner end of the side rubber member 20 in the tire radial direction, and comes into contact with a rim on which the tire 10 is mounted. A bead is provided on the outer side in the tire radial direction of the bead core 16 so as to be sandwiched between the portion of the carcass ply layer 12 wound around the bead core 16 and the portion of the carcass ply layer 12 wound around the bead core 16. A filler rubber member 22 is provided. An inner liner rubber member 26 is provided on an inner surface of the tire 10 facing an air-filled tire cavity region surrounded by the tire 10 and the rim.
In addition, the tire 10 includes a belt cover layer 28 which covers the belt layer 14 from the tire radial direction outer side of the belt layer 14 and is formed by coating organic fibers with rubber.

  Although the tire 10 has such a tire structure, the tire structure is not limited to the tire structure illustrated in FIG.

(Tread pattern)
FIG. 2 is a plan developed view of a part of the tread pattern obtained by developing an example of the tread pattern 30 of the tire 10 on a plane. As shown in FIG. 2, the tire 10 is designated with a rotation direction R indicating one direction in the tire circumferential direction. The direction of the rotation direction R is indicated and designated by numerals, symbols, and the like provided on the sidewall surface of the tire 10.

As shown in FIG. 2, the tread pattern 30 mainly has an inclined groove 32 and a transverse groove 34.
The inclined groove 32 is inclined with respect to the tire circumferential direction such that the inclined groove 32 extends outward in the tire width direction on each side of the tire center line CL on the opposite side to the rotation direction R (as it moves upward in FIG. 2). It is a groove that did. The inclined groove 32 is closed halfway without reaching the pattern end E. A plurality of inclined grooves 32 are provided at predetermined intervals in the tire circumferential direction.
The transverse groove 34 is inclined with respect to the tire circumferential direction so as to extend outward in the tire width direction as it advances in the opposite direction to the rotation direction R on both sides of the tire center line CL and further extends to the pattern ends E on both sides. It is a groove. A plurality of transverse grooves 34 are provided at predetermined intervals in the tire circumferential direction.
The inclination angle of the inclined groove 32 with respect to the tire circumferential direction is smaller than the inclination angle of the transverse groove 34 with respect to the tire circumferential direction at the same position in the tire width direction. Therefore, the transverse groove 34 intersects the inclined groove 32.
A plurality of wavy sipes 42 and 44 are provided on the tread surface. In FIG. 2, a plurality of holes 46 (stud pin mounting holes) are provided, and stud pins 48 (see FIG. 3) described later are mounted in the holes 46. In the hole peripheral area around the hole 46, concave portions 50A and 50B and convex portions 60A and 60B described later are provided. FIG. 2 shows the projections 50A and 50B as a representative.
The tread pattern of the tire 10 is not limited to the tread pattern 30 shown in FIG.

(Stud pin and stud pin mounting hole)
FIG. 3 is a diagram illustrating an example of the stud pin 48 and the hole 46.
The stud pin 48 protrudes from the tread surface when mounted on the tire 10, and has a tip portion 48 a in contact with the road surface and an embedded portion which fixes the tip portion 48 a and is embedded in the hole 46 provided in the tread rubber member 18. 48b. The buried portion 48b has a body portion 48c, a shank portion 48d, and a flange portion 48e in order from the side of the distal end portion 48a. The upper portion of the body portion 48c is exposed from the opening of the hole 46 at a portion where the tip portion 48a is fixed. The flange portion 48e is a flange-shaped protruding portion provided at an end opposite to the distal end portion 48a, and has a larger outer diameter than the body portion 48c. The shank portion 48d is provided between the body portion 48c and the flange portion 48e, and the outer diameter of the shank portion 48d is smaller than the outer diameter of the body portion 48c and the flange portion 48e.

  As shown in FIG. 1, the hole 46 has an enlarged diameter portion 46a corresponding to the flange portion 48e at the bottom of the hole, and a hole cross section is smaller on the hole opening side of the enlarged diameter portion 46a than the enlarged diameter portion 46a. A hole main body 46b having a fixed hole cross section and hole diameter is provided. The hole opening belongs to the hole body 46b having a certain hole cross section and hole diameter. However, a chamfer (not shown) in which the hole diameter increases toward the hole opening may be provided for the hole body 46b.

(Structure of the area around the hole)
Next, the configuration of the hole peripheral region of the stud pin mounting hole 45 will be described.
As shown in FIGS. 4 and 5, the tread portion of the tire 10 has a pair of concave portions 50A and 50B and a pair of convex portions 60A and 60B. FIG. 4 is a plan view showing the concave portions 50A and 50B and the convex portions 60A and 60B. In the following drawings, the contour shapes of the protrusions 60A and 60B represent the shape of the outermost tip surface in the tire radial direction when the protrusion height changes. FIG. 5 is a view taken along line VV of FIG. The spacing between the stud pins 48, the recesses 50A, 50B, and the protrusions 60A, 60B shown in FIGS. 5, 6B, and 7 is shown differently from FIG.
According to one embodiment, the hole peripheral region is preferably formed of a smooth surface having no irregularities except for the concave portions 50A and 50B and the convex portions 60A and 60B.

  The concave portions 50A and 50B are portions that are recessed inward in the tire radial direction in the hole peripheral region around the hole 46 on the tread surface. The concave portions 50A and 50B are arranged on both sides of the hole 46 in the tire circumferential direction, and extend linearly. When the tread surface is viewed in a direction perpendicular to the tread surface (in a plan view), the shape of the recesses 50A and 50B is a shape protruding toward the side approaching the hole 46 (hereinafter also referred to as a convex shape), or the tire circumferential direction. It is a straight line shape that crosses a straight line parallel to. The straight line parallel to the tire circumferential direction is a straight line parallel to the tire center line CL. According to one embodiment, the linear shape is preferably a shape extending in a direction (tire width direction) orthogonal to the tire circumferential direction. On the other hand, the linear shape may be inclined with respect to a direction orthogonal to the tire circumferential direction. In this case, the inclination angle is preferably larger than 0 degrees and 45 degrees or less.

  The convex portions 60A and 60B are portions that protrude outward in the tire radial direction in the hole peripheral region. The convex portions 60A and 60B are arranged farther from the hole 46 than the concave portions 50A and 50B, and extend linearly along the concave portions 50A and 50B.

  Here, with reference to FIGS. 6A and 6B, the operation of the concave portions 50A and 50B and the convex portions 60A and 60B during braking will be described. FIG. 6A is a diagram illustrating an operation of a stud tire of a comparative example described later, and FIG. 6B is a diagram illustrating an operation of the tire 10 of the present embodiment. The stud tire of the comparative example differs from the tire 10 of the present embodiment in that the protrusions 60A and 60B are not provided. 6A and 6B, the left-right direction coincides with the tire circumferential direction, and the traveling direction of the vehicle is indicated by an arrow from right to left.

  In a conventional tire, when snow or ice debris (hereinafter collectively referred to as snow S) is present on an icy road surface during braking, as shown in FIG. (In the direction of travel), it enters the recess 150A. For this reason, the ice powder I which has jumped forward due to the stud pin 148 shaving the road surface cannot enter the recess 150A. When the ice powder I not stored in the recess 150A enters between the tip 148a of the stud pin 148 and the road surface, the effect of the stud pin 148 scratching the road surface is reduced.

  On the other hand, in the tire 10 of the present embodiment, when braking, the snow S on the icy road surface collides with the protrusion 60A as shown in FIG. 6B, so that the snow S is behind the protrusion 60A (opposite to the traveling direction). Never enter. For this reason, the ice powder I which has protruded forward by the stud pin 48 shaving the road surface can enter the recess 50A, thereby suppressing the effect of the ice powder I of the stud pin 48 scratching the road surface being reduced. it can. At this time, even if the initial speed of the ice powder I is large, the ice powder I can enter the concave part 50A by hitting the convex part 60A and rebounding. In this manner, the reduction of the effect of the stud pins 48 scratching the road surface is suppressed, so that the braking performance on the icy road surface (on-ice braking performance) is improved.

  Further, in the tire 10 of the present embodiment, the projection 50A has a shape extending along the depression 50A when the tread surface is viewed in a plan view, that is, a projection, or a linear shape crossing the tire circumferential direction. Therefore, as compared with the case where the convex portion has a concave shape (concave shape) away from the hole 46, the snow S that has hit the convex portion 50 </ b> A from the front is more easily held by the convex portion 50 </ b> A. It is difficult for the snow S discharged on both sides in the tire width direction to enter between the protrusion 50A and the stud pin 48. Thereby, the above-described effect of improving the braking performance on ice is increased.

  If the amount of shaving by the stud pins 48 is large, the ice powder I that has protruded forward may not move in the recess 50A but may relatively move rearward from the stud pins 48. In this case, the ice powder I can enter the recess 50B. At this time, the ice powder I can enter the concave portion 50B by hitting the convex portion 60B and rebounding. Further, when the amount of the snow S to be shaved is large, the snow S collides with the convex portion 60B and is discharged to both sides in the tire width direction. Therefore, it is possible to suppress the entry of ice powder I or snow S in front of another stud pin 48 that contacts the ground behind the stud pin 48, and suppresses a reduction in the effect of the another stud pin 48 scratching the road surface. it can.

  Next, the operation of the concave portions 50A and 50B and the convex portions 60A and 60B during driving will be described with reference to FIG. FIG. 7 is a diagram illustrating the operation of the tire 10 according to the present embodiment. In FIG. 7, the left-right direction coincides with the tire circumferential direction, and the traveling direction of the vehicle is indicated by an arrow from right to left. Arrow R indicates the rotation direction of tire 10.

  At the time of driving, the tire 10 rotates, and the ice powder I generated by the stud pin 48 shaving the road surface jumps backward and enters the concave portion 50B. At this time, the ice powder I may hit the convex portion 60B and enter the concave portion 50B. Then, when the tire 10 further rotates and the tread surface including the hole peripheral area separates from the road surface, the ice powder I stored in the concave portion 50B falls and the space in the concave portion 50B is opened, so that the stud pin 48 When grounded, ice powder can be stored. Also, the ice powder I that has entered the front recess 50A at the time of braking falls when the tread surface leaves the road surface, and can accommodate the ice powder when the stud pin 48 is next grounded. As a result, the effect of the stud pins 48 scratching the road surface can be maintained, and driving performance on an ice road surface (driving performance on ice) is improved.

  The ice powder I dropped from the concave portions 50A and 50B can be removed on both sides of the convex portion 60A in the tire width direction when the front convex portion 60A hits from the front. For this reason, it can control that ice powder I remains behind to another stud pin 48 grounded in front of stud pin 48, and can control that the effect of another stud pin 48 scratching the road surface decreases. .

  According to one embodiment, it is preferable that the concave portions 50A and 50B and the convex portions 60A and 60B have the same contour shape in plan view. Further, according to one embodiment, it is preferable that the ends of the concave portions 50A and 50B and the convex portions 60A and 60B on the same side in the tire circumferential direction are equidistant from each other in any extending direction position. In other words, it is preferable that the contour shapes of the convex portions 60A and 60B when viewed in a plan view are shapes in which the contour shapes of the concave portions 50A and 50B are offset in the tire circumferential direction.

According to one embodiment, the convex shape is preferably an arc shape. Accordingly, it is possible to prevent the snow S contained in the concave portions 50A and 50B from locally clogging at a specific position in the extending direction of the concave portions 50A and 50B. On the other hand, the convex shape may be a bent shape as in the example shown in FIG. FIG. 8 is a plan view showing a modified example of the concave portions 50A and 50B and the convex portions 60A and 60B. According to one embodiment, when the tread portion is viewed in a plan view, it is preferable that the convex shapes of the convex portions 60A and 60B are also arc shapes. In this case, according to one embodiment, it is also preferable that the concave portions 50A and 50B and the convex portions 60A and 60B have an arc shape along a part of each of the concentric circles.
Further, according to one embodiment, it is preferable that the concave portion 50A and the convex portion 60A and the concave portion 50B and the convex portion 60B are line-symmetric with respect to a straight line passing through the center of the cross section of the hole 46 and parallel to the tire width direction. . Further, according to one embodiment, it is preferable that the hole 46 is point-symmetric with respect to the center of the cross section of the hole.

  According to one embodiment, the minimum distance between hole 46 and recesses 50A, 50B is preferably greater than 1 mm. If the minimum distance is 1 mm or less, the tightening force of the hole 46 on the stud pin 48 is weakened, and the stud pin 48 easily falls out of the hole 46. If the minimum distance is 1 mm or less, the convex portions 60A, 60B adjacent to the concave portions 50A, 50B are located at positions near the stud pins 48, so that it is difficult to contact the road surface. The minimum spacing is preferably at least 2 mm. On the other hand, the minimum interval is preferably 10 mm or less to make it difficult for ice powder or the like to enter the region between the recesses 50A and 50B and the stud pins 48.

  According to one embodiment, it is preferable that the concave depth of the concave portions 50A and 50B is longer than the protruding height of the convex portions 60A and 60B. With such a configuration, space in the concave portions 50A and 50B for accommodating the ice powder is secured, and the accommodating performance of the concave portions 50A and 50B is enhanced.

  According to one embodiment, the depth of the recesses 50A and 50B is preferably 2 to 10 mm. The recess depth refers to the depth of the recess from the connection position (base) between the recesses 50A and 50B and the smooth surface. If the dent depth is less than 2 mm, the space for accommodating the ice powder is small, and the scratching effect of the stud pins 48 may be reduced by the ice powder that is not accommodated. If the recess depth exceeds 10 mm, the rigidity of the rubber around the stud pin 48 decreases, and the tightening force of the rubber on the stud pin 48 decreases. For this reason, the stud pin 48 may easily fall out of the hole 46 in some cases. The depth of the recess is preferably 5 to 7 mm.

  According to one embodiment, the width of the recesses 50A and 50B (the length in the direction perpendicular to the extending direction) is preferably 0.5 to 2.0 mm. When the width of the concave portions 50A and 50B changes in the depth direction, the width at the connection position (base) between the concave portions 50A and 50B and the smooth surface is referred to. If the width of the recesses 50A and 50B is less than 0.5 mm, the space for accommodating the ice powder is small, and the scratching effect of the stud pins 48 may be reduced by the ice powder that is not accommodated. If the width of the concave portions 50A and 50B exceeds 2.0 mm, the rigidity of the rubber around the stud pin 48 decreases, and the tightening force of the rubber on the stud pin 48 decreases. For this reason, the stud pin 48 may easily fall out of the hole 46 in some cases. The width of the concave portions 50A and 50B is preferably 1.0 to 1.5 mm.

According to one embodiment, it is preferable that the protruding height of the protrusions 60 </ b> A, 60 </ b> B is lower than the height of the stud pin 48 attached to the hole 46 protruding from the hole 46. With such a configuration, the effect of the stud pins 48 scratching the road surface is ensured.
According to one embodiment, the height at which the stud pins 48 protrude is, for example, 0.8-1.5 mm, for example, 1.2 mm.

  According to one embodiment, it is preferable that the protruding height of the convex portions 60A and 60B is 0.2 to 1.5 mm. The protruding height refers to a protruding height from a connection position (base) between the convex portions 60A and 60B and the smooth surface. If the protruding height is less than 0.2 mm, the clearance between the ground and the road surface is large, and it is difficult to obtain the effect of discharging snow and the like to both sides in the tire width direction (snow discharging effect). If the protruding height exceeds 1.5 mm, the scratching effect of the stud pin 48 may be reduced, exceeding the protruding height of the stud pin 48 from the hole 46. The protrusion height of the protrusions 60A and 60B is preferably 0.5 to 1.0 mm.

  According to one embodiment, it is preferable that the width (length in the direction orthogonal to the extending direction) of the protrusions 60A and 60B is 0.5 to 2.0 mm. The width of the convex portions 60A, 60B refers to the width at the connection position (base) between the convex portions 60A, 60B and the smooth surface when the width changes in the height direction.

FIG. 9 is a diagram illustrating an example of the distribution of the protrusion heights of the protrusions 60A and 60B. In FIG. 9, the circumferential direction of the tire coincides with the depth direction of the drawing.
According to one embodiment, as shown in FIG. 9, the protrusions 60A and 60B have a distribution of protrusion heights along the extending direction, and the protrusion height is in the direction in which the protrusions 60A and 60B extend. Is preferably highest in the center between the two ends of. At this time, it is preferable that the protruding height is reduced as approaching both ends in the extending direction from the highest position. For example, when the convex portion 60A has the above-described convex shape, the snow S located in front of the convex portion 60A during the braking is likely to gather at the center in the extending direction of the convex portion 60A. Therefore, by increasing the height of the protrusion at the center in the extending direction of the convex portion 60A, it is possible to prevent the collected snow S from leaking to the rear of the convex portion 60A, and at both ends in the extending direction, By reducing the protruding height, the collected snow S can be quickly discharged to both sides in the tire width direction.

FIG. 10 is a diagram illustrating an example of the distribution of the widths of the protrusions 60A and 60B. In FIGS. 10 and 12 to 14, the tire circumferential direction coincides with the left-right direction, and only one side of the stud pin 48 in the tire circumferential direction shows a protrusion and a recess.
According to one embodiment, as shown in FIG. 10, the protrusions 60A and 60B have a width distribution along the extending direction, and the width of the protrusions 60A and 60B is equal to the width of the protrusions 60A and 60B. It is preferable that it is the widest at the center between both ends in the direction of presence. At this time, it is preferable that the width of the convex portions 60A and 60B is reduced as approaching both ends in the extending direction from the widest position. As described above, when the convex portion 60A has the above-mentioned convex shape, the snow S located in front of the convex portion 60A easily gathers at the center in the extending direction of the convex portion 60A during braking. Therefore, by maximizing the width of the protrusion 60A at the center in the extending direction, it is possible to suppress the snow S collected due to the deformation of the protrusion 60A from leaking to the rear of the protrusion 60A. In addition, by reducing the width of the protrusion 60A at both ends in the extending direction, the protrusion 60A is easily deformed, and the collected snow S is easily discharged to both sides in the tire width direction.

FIG. 11 is a diagram illustrating an example of the distribution of the depths of the recesses 50A and 50B. In FIG. 11, the tire circumferential direction coincides with the paper depth direction.
According to one embodiment, as shown in FIG. 11, the recesses 50A and 50B have a distribution of recess depths along the extending direction, and the recess depths are both ends in the extending direction of the recesses 50A and 50B. It is preferably deepest in the middle between. At this time, it is preferable that the depth of the recess becomes shallower as approaching both ends in the extending direction from the deepest position. Since the ice powder shaved by the stud pins 48 is most likely to accumulate at the center of the recesses 50A and 50B, the capacity of accommodating the recesses 50A and 50B can be enhanced by making the depth of the recess the deepest at the center in the extending direction.

FIG. 12 is a diagram illustrating an example of the distribution of the widths of the concave portions 50A and 50B.
According to one embodiment, the recesses 50A, 50B have a width distribution along the extending direction, as shown in FIG. 12, and the width of the recesses 50A, 50B is in the extending direction of the recesses 50A, 50B. Preferably, it is widest at the center between the ends. At this time, it is preferable that the widths of the concave portions 50A and 50B are reduced from the widest position toward the both ends in the extending direction. Since the ice powder shaved by the stud pins 48 is most likely to accumulate in the centers of the recesses 50A and 50B, the accommodating performance of the recesses 50A and 50B is improved by making the width of the recesses 50A and 50B the largest in the center in the extending direction. Can be.

FIG. 13 is a plan view illustrating the expected angles of the concave portions 50A and 50B and the convex portions 60A and 60B.
According to one embodiment, the prospective angles θ of the concave portions 50A and 50B and the convex portions 60A and 60B viewed from the center of the cross section of the hole 46 along the surface of the tread portion are, as shown in FIG. It is preferred that Is less than 60 degrees, the snow S easily enters the hole surrounding area from the lateral direction with respect to the rotation direction R when turning, and the effect of the stud pins 48 scratching the road surface may be reduced. It is preferable that the expected angle θ is equal to or less than 90 degrees. According to one embodiment, the estimated angle θ is preferably equal on both sides in the tire width direction with respect to a straight line passing through the hole 46 and parallel to the tire circumferential direction.

Here, the ground area of the tread portion has a center area Ce and a shoulder area Sh, as shown in FIG.
The center area Ce is an area located on both sides in the tire width direction from the tire center line CL in a range of a length of 25% or less of the ground contact width. This range is, for example, 5% or more of the contact width. The shoulder region Sh is a region located outside the center region Ce in the tire width direction.
The ground contact region is a region of the tread surface that becomes a ground contact surface when the tire 10 is assembled on a regular rim, filled with a regular internal pressure, and grounded on a horizontal surface under a condition where a load is 88% of the regular load. The contact width is the length in the tire width direction between both ends (contact end) of the contact surface in the tire width direction. The regular rim refers to a “measurement rim” specified by JATMA, a “Design Rim” specified by TRA, or a “Measuring Rim” specified by ETRTO. The normal internal pressure refers to the “maximum air pressure” specified by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified by TRA, or “INFLATION PRESSURES” specified by ETRTO. The normal load refers to the “maximum load capacity” specified by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified by TRA, or “LOAD CAPACITY” specified by ETRTO.
According to one embodiment, the plurality of holes 46 are provided in the center region Ce and the shoulder region Sh, and the prospective angles of the concave portions 50A, 50B and the convex portions 60A, 60B may be wider in the shoulder region than in the center region. preferable. According to such an embodiment, in the center region Ce that contributes to the improvement of the braking performance, snow and ice powder are effectively discharged along the tire circumferential direction, and the shoulder Sh that contributes to the improvement of the turning performance has the tire It is possible to effectively discharge snow and ice powder along the lateral direction inclined with respect to the circumferential direction. Is, for example, 90 to 120 degrees in the shoulder region.

FIG. 14 is a plan view illustrating the maximum gap G between the concave portions 50A and 50B and the convex portions 60A and 60B.
According to one embodiment, the maximum distance G between the concave part 50A and the convex part 60A located on the same side in the tire circumferential direction with respect to the hole 46, or the maximum distance G between the concave part 50B and the convex part 60B is the concave part 50A. Alternatively, the length is preferably equal to or less than twice the width of the concave portion 50B. The maximum interval G means an interval in a direction along the tire circumferential direction. The width of the recess means the width at the same position in the tire width direction as the interval. If the maximum distance G exceeds the double length, the ice powder may hit the convex portions 60A and 60B, bounce back, and the effect of being accommodated in the concave portions 50A and 50B may be reduced. On the other hand, the concave portion 50A and the convex portion 60A or the concave portion 50B and the convex portion 60B may be in contact with each other. That is, the maximum interval G may be 0 mm.
According to one embodiment, the maximum gap G is preferably 1 to 4 mm.

  According to one embodiment, of the recesses 50A and 50B, the first recess 50A located on the side opposite to the rotation direction R with respect to the hole 46 is smaller than the second recess 50B located on the rotation direction R side. It is preferable that the maximum width of the first concave portion 50A is large or the maximum concave depth is large. Since the first concave portion 50A is located on the side where the ice powder jumps out during braking, the above-described embodiment is effective from the viewpoint of increasing the ice powder storage performance. The maximum width and the maximum depth of the first recess 50A are preferably 1.2 to 2 times the maximum width and the maximum depth of the second recess 50B.

  According to one embodiment, of the convex portions 60A and 60B, the first convex portion 60A located on the side opposite to the rotation direction R with respect to the hole 46 is the second convex portion located on the side in the rotational direction R. It is preferable that the first protrusion 60A has a wider maximum width or a higher maximum protrusion height than the portion 60B. Since the first convex portion 60A is located on the side where the front snow S hits during braking, the above-described embodiment is effective from the viewpoint of increasing snow removal performance. The maximum width and the maximum projection height of the first projection 60A are preferably 1.2 to 2 times the maximum width and the maximum projection height of the second projection 60B.

According to one embodiment, it is preferred that the recesses 50A and 50B extend without interruption between both ends in the extending direction. If the concave portions 50A and 50B are interrupted in the middle of the extending direction, the capacity for storing the ice powder I is greatly reduced.
According to one embodiment, it is preferable that the protrusions 60A and 60B extend without interruption between both ends in the extending direction. If the protrusions 60A and 60B are interrupted in the middle of the extending direction, the snow removal performance is significantly reduced.

  According to one embodiment, it is preferred that the concave portions 50A and 50B are not connected to either the inclined groove 32 or the transverse groove 34. When the hole 46 is provided at a position close to the inclined groove 32 or the transverse groove 34, if the concave portions 50A, 50B are connected to these grooves 32, 34, the rigidity of the rubber in the region around the hole is reduced. For this reason, the tightening force of the rubber on the stud pin 48 is weakened, and the stud pin 48 may easily fall out of the hole 46.

  In the present embodiment, the concave portions 50A, 50B and the convex portions 60A, 60B only need to be provided in the hole peripheral region of at least one of the plurality of holes 46, and are provided in the hole peripheral regions of all the holes 46. Preferably.

(Example, Comparative Example, Conventional Example)
In order to confirm the effects of the present invention, four tires each having a tire size of 205 / 55R16 were prepared for each of the following Examples, Comparative Examples, and Conventional Examples, and mounted on a front-wheel-drive passenger car having a displacement of 2 L. The braking performance on ice and the driving performance on ice were examined. The rim size of the vehicle was 16 × 6.5 J, and the air pressure was 210 kPa.
Except for the points shown in Table 1, the tires of Examples 1 to 8 were based on the tread pattern 30 shown in FIG. 2 and provided with concave portions and convex portions having the forms shown in FIGS.
In each case, the height of the stud pin projecting from the stud pin mounting hole was 1.1 mm.

In the conventional example, a pair of convex portions is not provided, and the concave portion is provided so as to be linearly separated in three directions from the stud pin mounting hole from a position spaced from the stud pin mounting hole. Specifically, one recess is provided so as to move away from the rotation direction, and the other two recesses are inclined with respect to the rotation direction so as to move away from the stud pin mounting hole. It was provided so as to move away in the direction.
The comparative example was the same as Example 1 except that the convex portions were omitted.
In Comparative Examples and Examples 1 to 8, the minimum distance between the stud pin mounting hole and the concave portion was 3 mm.
In Comparative Example and Examples 1 to 8, the prospective angle θ was the same angle in both the center region and the shoulder region.

In Examples 1 to 8, except for the points shown in Table 1, with respect to the concave and convex portions on the same side in the tire circumferential direction, the length in the extending direction was equal, and the radius of curvature of the arc shape was equal.
In Examples 1 to 8, the maximum distance between the concave portion and the convex portion was 1.5 mm.
The depth of the dents in Examples 3 and 4 was 1.3 mm at the maximum at the middle point in the extending direction and was 1.0 mm at the minimum.
The width of the concave portion in Example 4 was 1.0 mm at the maximum at the middle point in the extending direction and was 0.5 mm at the minimum. The width became narrower as approaching both ends in the extending direction.
The protruding height of Examples 5 and 6 was 0.7 mm at the maximum at the midpoint in the extending direction, and was reduced toward the both ends in the extending direction, which was 0.4 mm at the minimum.
The width of the convex portion in Example 6 was 1.0 mm at the maximum at the middle point in the extending direction, and was narrowed to 0.5 mm at the both ends in the extending direction.
In Example 8, the concave portion and the convex portion had a linear shape extending in a direction orthogonal to the tire circumferential direction passing through the stud pin mounting hole.

In Table 1, “the shape of the concave portion and the convex portion” means a drawing number or the like that best represents the shape of the concave portion and the convex portion. “Line” means a straight line shape.
With respect to the columns of “depth of the recess”, “width of the recess”, “height of the protrusion”, and “width of the protrusion”, “change” means that the length is changed from the middle point to both ends in the extending direction.
"Estimated angle" indicates the estimated angle of the convex portion. Each of the protrusions and the recesses was extended at equal angles on both sides in the tire width direction with respect to the tire circumferential direction.

(Breaking performance on ice)
The distance (braking distance) from the state of traveling at 50 km / hour on an icy road to the point where the brake pedal is depressed to the deepest position and stopped (braking distance) was measured five times, and the reciprocal of the average value was used to set the comparative example as 100. Indexed. The larger the index, the shorter the distance and the better the performance on ice. When the index was 101 or more, it was evaluated that the braking performance on ice was excellent.
(Drive performance on ice)
The acceleration time required until the traveling speed became 20 km / hour was measured five times from a state where the vehicle was traveling at 5 km / hour on an icy road, and the reciprocal of the average value was used to index the comparative example as 100. The larger the index is, the shorter the acceleration time is and the better the driving performance on ice is. When the index was 101 or more, it was evaluated that the driving performance on ice was excellent.

From a comparison between the comparative example and Examples 1 to 8, it is understood that the provision of the pair of convex portions extending linearly along the concave portion improves the braking performance on ice and the driving performance on ice.
From a comparison between Example 1 and Example 2, it is understood that the braking performance on ice is improved by the concave and convex portions having the arc shape.

A comparison between Example 1 and Example 3 shows that the on-ice braking performance and the on-ice driving performance are improved when the recess depth of the concave portion is reduced from the center to both ends in the extending direction.
A comparison between Example 3 and Example 4 shows that the on-ice braking performance and on-ice driving performance are improved when the width of the concave portion is reduced from the center to both ends in the extending direction.

From a comparison between Example 1 and Example 5, it can be seen that the on-ice braking performance and on-ice driving performance are improved when the protrusion height of the protrusion decreases from the center to both ends in the extending direction.
A comparison between Example 5 and Example 6 shows that the on-ice braking performance and on-ice driving performance are improved when the width of the convex portion is reduced from the center to both ends in the extending direction.

From a comparison between Example 1 and Example 7, it is understood that the braking performance on ice and the driving performance on ice are improved when the expected angle of the concave portion and the convex portion is 60 degrees or more.
From a comparison between Example 1 and Example 8, it can be seen that the on-ice braking performance and on-ice driving performance are improved by the fact that the shape of the concave and convex portions when viewed in plan is convex.

  As described above, the pneumatic tire and the stud tire of the present invention have been described in detail, but the present invention is not limited to the above-described embodiments and examples, and various modifications and changes are made without departing from the gist of the present invention. Of course it is good.

10 Pneumatic tire 18 Tread rubber member 30 Tread pattern 46 holes (stud pin mounting holes)
48 Stud pins 50A, 50B Concave parts 60A, 60B Convex parts

Claims (14)

A pneumatic tire,
Equipped with an annular tread in the tire circumferential direction,
The tread portion,
A plurality of stud pin mounting holes to which stud pins are mounted,
A pair of recesses recessed inward in the tire radial direction in a hole peripheral region on the surface of the tread portion around at least one stud pin mounting hole of the stud pin mounting holes,
The recess is disposed on both sides of the at least one stud pin mounting hole in the tire circumferential direction, extends linearly,
When the surface of the tread portion is viewed in a direction perpendicular to the surface, the shape of the recess is a shape protruding toward the side approaching the at least one stud pin mounting hole, or a straight line parallel to the tire circumferential direction. It is a straight line that traverses,
The tread portion further has a pair of convex portions projecting outward in the tire radial direction in the hole peripheral region,
The pneumatic tire, wherein the protrusion is disposed farther from the stud pin mounting hole than the recess, and extends linearly along the recess.   The pneumatic tire according to claim 1, wherein the protruding shape is an arc shape.   The pneumatic tire according to claim 1, wherein a depth of the recess is longer than a height of the protrusion.   4. The projection according to claim 1, wherein a protrusion height of the protrusion is lower than a height at which a stud pin attached to the at least one stud pin attachment hole projects from the stud pin attachment hole. 5. The pneumatic tire as described. The protrusion has a distribution of protrusion heights along the extending direction,
The pneumatic tire according to any one of claims 1 to 4, wherein the protruding height is highest at a center between both ends in the extending direction of the protrusion. The protrusion has a width distribution along the extending direction,
The pneumatic tire according to any one of claims 1 to 5, wherein the width of the protrusion is the largest at the center between both ends in the extending direction of the protrusion. The recess has a distribution of recess depth along the extending direction,
The pneumatic tire according to any one of claims 1 to 6, wherein the depth of the recess is deepest at a center between both ends in the extending direction of the recess. The recess has a width distribution along the extending direction,
The pneumatic tire according to any one of claims 1 to 7, wherein the width of the concave portion is the largest at the center between both ends in the extending direction of the concave portion.   9. The projected angle of the concave portion and the convex portion as viewed from the center of the cross section of the at least one stud pin mounting hole along the surface of the tread portion is 60 degrees or more. 10. The pneumatic tire according to the paragraph. The ground area of the tread portion,
A center area located within a range of not more than 25% of the contact width on both sides in the tire width direction from the tire center line;
A shoulder region located outside the center region in the tire width direction,
The at least one stud pin mounting hole is provided in the center region and the shoulder region,
The pneumatic tire according to claim 9, wherein the prospective angles of the concave portion and the convex portion are wider in the shoulder region than in the center region.   The maximum distance between the concave portion and the convex portion located on the same side in the tire circumferential direction with respect to the at least one stud pin mounting hole is not more than twice the width of the concave portion. The pneumatic tire according to any one of items 10 to 10. The rotation direction of the pneumatic tire is specified,
Among the recesses, a first recess located on a side opposite to the rotation direction with respect to the at least one stud pin mounting hole is compared with a second recess located on the rotation direction side in the first recess. The pneumatic tire according to any one of claims 1 to 11, wherein the maximum width of the recess is wide or the maximum depth of the recess is deep.   The pneumatic tire according to any one of claims 1 to 12, wherein a minimum distance between the at least one stud pin mounting hole and the recess exceeds 1 mm. A pneumatic tire according to any one of claims 1 to 13,
A stud pin attached to a stud pin attachment hole of the pneumatic tire.

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