阅读说明：本技术 轮胎 (Tyre for vehicle wheels ) 是由 石野裕之 桥本祐人 于 2020-01-17 设计创作，主要内容包括：本发明提供一种能够发挥优异的冰上性能的轮胎。所述轮胎包括胎面部(2)。胎面部(2)包括从其接地面(2s)凹陷的凹部(7)。凹部(7)包括底面(8)、和与底面(8)及接地面(2s)相连的内周面(9)。在凹部(7)设置有在底面(8)开口的销钉固定用的孔(5)、和从底面(8)突出的多个凸部(10)。凸部(10)包括第一凸部(11),所述第一凸部(11)与接地面(2s)相连且比接地面(2s)更向轮胎半径方向外侧突出。(The invention provides a tire capable of exerting excellent on-ice performance. The tire includes a tread portion (2). The tread portion (2) includes a recess (7) recessed from the ground contact surface (2s) thereof. The recess (7) includes a bottom surface (8) and an inner peripheral surface (9) connected to the bottom surface (8) and the ground surface (2 s). The recessed portion (7) is provided with a hole (5) for fixing a pin, which opens in the bottom surface (8), and a plurality of protruding portions (10) which protrude from the bottom surface (8). The convex portion (10) includes a first convex portion (11), and the first convex portion (11) is connected to the ground contact surface (2s) and protrudes further outward in the tire radial direction than the ground contact surface (2 s).)

1. A tire, wherein,

the tire includes a tread portion having a tread surface,

the tread portion includes a recess recessed from a ground-contacting surface thereof,

the concave part comprises a bottom surface and an inner circumferential surface connected with the bottom surface and the ground plane,

the recessed portion is provided with a hole for fixing a pin, which is opened in the bottom surface, and a plurality of protruding portions protruding from the bottom surface,

the convex portion includes a first convex portion that is connected to the ground contact surface and protrudes further outward in the tire radial direction than the ground contact surface.

2. The tire according to claim 1, wherein,

the first convex portion has a length in a rotational direction of the inner peripheral surface that gradually increases toward the hole when the tread is viewed in plan.

3. The tire according to claim 1, wherein,

the first convex portion has a length in a rotational direction of the inner peripheral surface that gradually decreases toward the hole when the tread is viewed in plan.

4. The tire according to any one of claims 1 to 3,

the convex portion includes a second convex portion spaced apart from the inner peripheral surface.

5. The tire according to claim 4,

the second convex portion protrudes further outward in the tire radial direction than the first convex portion.

6. The tire according to claim 4 or 5,

a first length of the second convex portion in a rotational direction of the inner peripheral surface is larger than a second length in a radiation direction from the hole toward the inner peripheral surface when the tread is viewed in plan.

7. The tire according to any one of claims 4 to 6,

the hole is surrounded by the plurality of first projections and the plurality of second projections.

8. The tire according to claim 7,

the first convex portions and the second convex portions are alternately arranged in a rotational direction along the inner peripheral surface.

Technical Field

The present invention relates to a tire, and more particularly to a tire having a tread portion provided with a hole for fixing a pin.

Background

Patent document 1 listed below proposes a winter tire in which a hole for fixing a pin is provided in a tread portion. The tread portion of the winter tire is provided with a recess recessed from the tread surface. The recess is provided with the hole and a protrusion that protrudes outward of the tire radius at a position spaced apart from the hole.

Patent document 1: japanese patent laid-open publication No. 2017-071339

Disclosure of Invention

With the winter tire of patent document 1, the ice debris is discharged from the recessed portion by the projection, thereby achieving an improvement in on-ice performance. However, according to the experimental results of the inventors, there is room for further improvement in the improvement of the on-ice performance.

The present invention has been made in view of the above problems, and a main object thereof is to provide a tire capable of exhibiting excellent on-ice performance.

The present invention is a tire including a tread portion, the tread portion including a concave portion recessed from a ground contact surface thereof, the concave portion including a bottom surface and an inner peripheral surface connected to the bottom surface and the ground contact surface, the concave portion being provided with a hole for pin fixation opened in the bottom surface and a plurality of convex portions protruding from the bottom surface, the convex portions including a first convex portion connected to the ground contact surface and protruding further outward in a tire radial direction than the ground contact surface.

Preferably, when the tread of the tire of the present invention is viewed in plan, the length of the first convex portion in the rotational direction of the inner circumferential surface gradually increases toward the hole.

Preferably, when the tread of the tire of the present invention is viewed in plan, the length of the first convex portion in the rotational direction of the inner circumferential surface is gradually reduced toward the hole.

Preferably, in the tire of the present invention, the convex portion includes a second convex portion spaced apart from the inner peripheral surface.

In the tire of the present invention, it is preferable that the second convex portion protrudes further outward in the tire radial direction than the first convex portion.

Preferably, when the tread of the tire of the present invention is viewed in plan, a first length of the second convex portion in the rotational direction of the inner circumferential surface is longer than a second length in a radial direction from the hole toward the inner circumferential surface.

In the tire of the present invention, the hole is preferably surrounded by the plurality of first protrusions and the plurality of second protrusions.

Preferably, in the tire of the present invention, the first convex portions and the second convex portions are alternately arranged in a rotational direction along the inner peripheral surface.

In the tire of the present invention, the first convex portion prevents ice chips from entering the concave portion. Therefore, the protruding height of the pin can be suppressed from being reduced by the ice debris. In addition, the first convex part is connected with the ground plane. Therefore, the first convex portion has excellent durability, prevents early chipping and the like, and improves the on-ice performance for a long period of time.

Drawings

Fig. 1 is a developed view of a tread portion of a tire of the present embodiment.

Fig. 2 is an enlarged perspective view of the recess of fig. 1.

Fig. 3 is an enlarged plan view of the recess of fig. 1.

Fig. 4 is a sectional view taken along line a-a of fig. 3.

Fig. 5 is an enlarged perspective view of a recess in another embodiment of the present invention.

Fig. 6 is an enlarged plan view of the recess of fig. 5.

Fig. 7 is an enlarged perspective view of a recess of a comparative example.

Detailed Description

Next, an embodiment of the present invention will be described based on the drawings. Fig. 1 shows a tread portion 2 of a tire 1 of the present embodiment. In the tire 1 of the present embodiment, a hole 5 for fixing a pin is provided in the tread portion 2, and a pin (not shown) is used by being fitted into the hole 5. The tire 1 of the present embodiment is suitably used as a winter tire for a car, for example. The pin provides a large friction when driving on ice. Hereinafter, the structure of the tire 1 will be described in a state where it is mounted on a predetermined rim and is under no load filled with a predetermined internal pressure, and in a state where a pin is not mounted on the hole 5, unless otherwise described.

The "predetermined Rim" is a Rim defined for each tire in a specification system including a specification under which the tire is based, and is, for example, "standard profile" in the case of JATMA, "Design Rim" in the case of TRA, or "Measuring Rim" in the case of ETRTO.

The "predetermined internal PRESSURE" is a standard system including a standard according to which TIREs are subjected, and the standard is an air PRESSURE defined for each TIRE, and is a maximum value described in a table "TIRE LOAD limit AT variable cold INFLATION PRESSURES" in the case of JATMA, a maximum value in the case of TRA, and is an "INFLATION PRESSURE" in the case of ETRTO.

The rubber hardness of the tread 2 is, for example, 45 to 65 degrees. In the present specification, the hardness of the rubber is represented by JIS-A hardness based on JIS-K6253.

The tread portion 2 is formed of, for example, a plurality of blocks partitioned by a plurality of grooves. The pattern of the tread portion 2 is not particularly limited in the present invention, and may be configured to include, for example, ribs that are continuous in the tire circumferential direction. The blocks disposed in the tread portion 2 are provided with a plurality of concave portions 7 recessed from the ground contact surface 2s of the tread portion 2.

Fig. 2 shows an enlarged perspective view of the recess 7 of fig. 1. Fig. 3 shows an enlarged plan view of the recess 7 of fig. 1. Fig. 4 shows a cross-sectional view taken along line a-a in fig. 3. As shown in fig. 2 to 4, the recess 7 includes a bottom surface 8 and an inner peripheral surface 9 continuous with the bottom surface 8.

As shown in fig. 2, the recess 7 is recessed by, for example, an area surrounded by an edge 7e having a closed contour. The contour of the recess 7 may be formed in various shapes such as a circle, an ellipse, and a polygon. The recess 7 of the present embodiment has, for example, a circular contour.

The width of the recessed portion 7 in a plan view of the tread (corresponding to the diameter of the recessed portion 7 in the present embodiment) is, for example, 20mm or less, preferably 14 to 18 mm. This ensures a sufficient area of the ground contact surface 2s of the tread portion 2.

As shown in FIG. 4, the depth d1 of the recess 7 is, for example, 0.2 to 1.5mm, preferably 0.2 to 0.7 mm. The size of the recess 7 is not limited to this.

As shown in fig. 2, the recessed portion 7 is provided with a pin fixing hole 5 opening on the bottom surface 8 and a plurality of projecting portions 10 projecting from the bottom surface 8.

The pin fixing hole 5 has an inner diameter smaller than the outer diameter of the pin, for example. When the tire is used, the pin is inserted into the hole 5, and the tip of the pin is exposed to the outside of the tread portion 2. This is expected to result in a large frictional force on ice. The holes 5 have, for example, a circular contour in a plan view of the tread portion 2.

The convex portion 10 includes a first convex portion 11 which is continuous with the ground contact surface 2s and protrudes outward in the tire radial direction from the ground contact surface 2 s.

The first protrusion 11 prevents ice debris from entering the recess 7. Therefore, the protruding height of the pin can be suppressed from being reduced by the ice debris. Further, the first convex portion 11 is connected to the ground plane 2 s. Therefore, the first convex portion 11 has excellent durability, prevents early chipping and the like, and improves the on-ice performance for a long period of time.

As shown in fig. 3, in a tread plane view, for example, the length of the inner circumferential surface 9 of the first convex portion 11 in the rotational direction is preferably gradually increased toward the hole 5. Thus, the outer surface of the first convex portion 11 is trapezoidal in a plan view of the tread. Such first convex portion 11 is easy to tilt in the rotation direction of the inner peripheral surface 9 with a connecting portion with the inner peripheral surface 9 as a fulcrum, and can effectively discharge ice debris. The outer surface of the trapezoid includes not only a complete trapezoid but also a mode of rounding the apex and a mode of slightly bending the side.

The maximum length L1 in the rotational direction of the first convex portion 11 is, for example, 5.0mm or less, preferably 1.0 to 3.0 mm. Preferably, the length L1 is 3% to 8% of the length of the inner circumferential surface 9 in the rotational direction.

The minimum length L2 of the first convex part 11 in the rotating direction is, for example, 0.50 to 0.70 times the length L1. Such first convex portion 11 can maintain durability and exert the above-described effects.

The side surface of the first projection 11 includes, for example, a first surface 16 on the hole 5 side, and a second surface 17 and a third surface 18 between the first surface 16 and the inner peripheral surface 9.

Preferably, the first surface 16 is recessed outward in the radial direction (in the present embodiment, the radial direction corresponding to the circular outline of the recess 7) from the hole 5 toward the inner circumferential surface 9. Thus, the first surface 16 includes a portion extending parallel to the inner circumferential surface 9 in a tread plane view. The distance L3 in the radiation direction from the center of the hole 5 to the first surface 16 is, for example, 5.0mm or less, preferably 2.5 to 4.5 mm.

The angle θ 1 between the second surface 17 and the third surface 18 is, for example, preferably 90 ° or less, more preferably 45 ° or less, and in the present embodiment, 20 to 40 °. Such first convex portion 11 is easily deformed appropriately in the rotational direction, and effectively discharges the ice debris in the concave portion 7.

As shown in FIG. 4, the height h1 of the first protrusion 11 from the ground plane is preferably 0.5 to 2.0mm, for example. Such first convex portion 11 is less likely to be damaged at the time of grounding, and entry of ice debris into the concave portion 7 is effectively suppressed. The first convex portion 11 can also contribute to improvement in rigidity of rubber around the hole 5 and also to improvement in pin retainability.

As shown in fig. 3, the convex portion 10 of the present embodiment includes, for example, a second convex portion 12 spaced apart from the inner peripheral surface 9. For example, the first length L4 of the second convex part 12 in the rotational direction is greater than the second length L5 of the radiation direction. The first length L4 is, for example, 5.0mm or less, preferably 2.5 to 4.5 mm. The second length L5 is, for example, 0.8 to 1.5 mm. Thereby, the second convex portion 12 is flattened in the radiation direction. Such second convex portion 12 is inclined in the radial direction when the ground pressure acts, and the ice debris can be effectively discharged from the concave portion 7. In particular, in the present embodiment, the first convex portion 11 is easily inclined in the rotation direction, and the second convex portion 12 is easily inclined in the radiation direction, and therefore, an excellent discharge function is exhibited.

It is preferable that the first length L4 of the second protrusions 12 is greater than the length L1 of the first protrusions 11. Specifically, the first length L4 of the second convex portion 12 is preferably 1.5 to 2.5 times the length L1 of the first convex portion 11.

The second length L5 is preferably 0.5 times or less, and more preferably 0.25 to 0.40 times the first length L4. Such second convex portion 12 is easily inclined in the radial direction and has excellent durability.

The second convex portion 12 includes, for example, an inner surface 21 on the hole 5 side and an outer surface 22 on the inner peripheral surface 9 side of the concave portion. The inner surface 21 and the outer surface 22 extend along the inner circumferential surface 9 of the recess 7, and preferably extend parallel to the inner circumferential surface 9. Further, two circular arc surfaces 23 are connected between the inner side surface 21 and the outer side surface 22. Thereby, the second convex portion 12 forms an oval shape convexly curved toward the outside in the radiation direction in the tread plane view.

The minimum distance L6 in the radial direction from the center of the hole 5 to the inner surface 21 is, for example, 3.0 to 4.0 mm. The inner surface 21 of the second convex portion 12 is preferably located more inward in the radiation direction than the first surface 16 of the first convex portion 11, for example. Further, the outer surface 22 of the second convex portion 12 is preferably located further outward in the radiation direction than the first surface 16 of the first convex portion 11. Such second convex portion 12 can effectively suppress ice debris from remaining in the concave portion 7.

As shown in fig. 4, the second convex portion 12 preferably protrudes further outward in the tire radial direction than the first convex portion 11. The height h2 of the second projection 12 from the bottom surface 8 is preferably 1.0 to 2.5mm, for example.

As shown in fig. 3, a plurality of second protrusions 12 and a plurality of first protrusions 11 are provided at intervals in the rotational direction around the hole 5. Thereby, the hole 5 is surrounded by the plurality of second protrusions 12 and the plurality of first protrusions 11. Preferably, 2 to 4 second protrusions 12 and first protrusions 11 are arranged in the recess 7, respectively. Preferably, the second convex portions 12 and the first convex portions 11 are alternately arranged in the rotational direction along the inner peripheral surface 9.

The size of the gap between the first convex portion 11 and the second convex portion 12 is not particularly limited. Preferably, in the present embodiment, the length of the gap between the first convex portion 11 and the second convex portion 12 in the rotational direction is smaller than the length of the second convex portion 12 in the rotational direction.

Fig. 5 shows an enlarged perspective view of a recess 7 according to another embodiment of the present invention, and fig. 6 shows a plan view of fig. 5. In fig. 5 and 6, the same reference numerals are given to elements common to the above-described embodiments, and the description thereof is omitted. As shown in fig. 5 and 6, the first convex portion 11 of this embodiment has a length in the rotational direction of the inner circumferential surface 9 that gradually decreases toward the hole 5 in a plan view of the tread. Thus, the outer surface of the first convex portion 11 forms a triangle in a tread plane view. Such first convex portion 11 contributes to the above-described effects, facilitates recognition of the position of the hole 5, and improves the operability when inserting the pin into the hole 5. In addition, the outer surface of the triangle includes not only a complete triangle but also a mode in which the vertex is rounded and a mode in which the side is slightly curved.

As shown in fig. 6, the maximum length L1 in the rotational direction of the first convex portion 11 is, for example, 5.0mm or less, preferably 1.0 to 3.0 mm. The distance L7 from the center of the hole 5 to the apex 24 of the first projection 11 is, for example, 5.0mm or less, preferably 2.5 to 4.5 mm.

As shown in fig. 6, the angle θ 2 between the two surfaces sandwiching the apex 24 of the first projection 11 is, for example, 40 to 60 °. Such a first projection 11 efficiently discharges ice debris.

Although the tire according to the embodiment of the present invention has been described in detail, the present invention is not limited to the above-described embodiment, and may be modified in various ways.