Pneumatic tire

Abstract

To provide a pneumatic tire that is able to firmly fix a tire chain.SOLUTION: In a pneumatic tire 10 provided with a tread 11, the tread 11 has a shoulder block 12 disposed outside in a tire axial direction. Formed in the shoulder block 12 is a lateral groove 31 communicating with an outer end in the tire axial direction. Formed outside in the tire axial direction of the shoulder block 12 is a projection 40 projecting outward in the tire axial direction. Each of the protrusions 40 is formed at an end of the shoulder block 12 in a tire circumferential direction across the lateral groove 31.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] Pneumatic tires may be fitted with tire chains to prevent slipping on snowy or icy roads. The tire chains must be firmly fixed to the pneumatic tire to prevent the tire from slipping. The tire chains may be fixed to the pneumatic tire by engaging with lateral grooves that define the shoulder blocks of the pneumatic tire (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 07-290908 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to securely attach the tire chain to the pneumatic tire, it is possible to make the lateral groove deeper. However, if the lateral groove is made deeper, the rigidity of the shoulder block decreases, and uneven wear may occur in which the outer portion of the shoulder block wears faster than the inner portion in the axial direction of the tire. Therefore, another measure to securely attach the tire chain to the pneumatic tire is desired.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a pneumatic tire to which a tire chain can be firmly fixed. [Means for solving the problem]

[0006] The pneumatic tire of the present invention is a pneumatic tire having a tread, the tread having a shoulder land arranged on the outside in the tire axial direction, a lateral groove formed in the shoulder land connecting to the outer end in the tire axial direction, a protrusion formed on the outer surface in the tire axial direction of the shoulder land that protrudes toward the outside in the tire axial direction, and the protrusions are formed at each of the circumferential ends of the tire on either side of the lateral groove of the shoulder land. Effect of the Invention

[0007] According to the pneumatic tire of the present invention, the tire chain can be firmly fixed while maintaining the rigidity of the shoulder. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating a pneumatic tire as an example of an embodiment. [Diagram 2] FIG. 2 is a detailed perspective view of part A in FIG. [Diagram 3] FIG. 2 is a detailed perspective view of part A in FIG. 1, which is another example of the embodiment. [Figure 4] 1 is a schematic side view of a pneumatic tire as an example of an embodiment. [Diagram 5] 3 is a cross-sectional view of FIG. 2 taken along line B-B. [Figure 6] 3 is a cross-sectional view taken along line BB of FIG. 2 of a pneumatic tire which is another example of an embodiment. FIG. [Figure 7] 3 is a cross-sectional view taken along line BB of FIG. 2 of a pneumatic tire which is another example of an embodiment. FIG. [Figure 8] FIG. 3 is a comparison of the BB cross-sectional view and the CC cross-sectional view in FIG. 2. [Figure 9] 3 is a cross-sectional view taken along line BB of FIG. 2 of a pneumatic tire which is another example of an embodiment. FIG. [Figure 10] 3 is a cross-sectional view taken along line BB of FIG. 2 of a pneumatic tire which is another example of an embodiment. FIG. [Figure 11] 2 is a cross-sectional view of part A in FIG. 1 in the tire circumferential direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An example of an embodiment of the present invention will be described in detail below. In the following description, specific shapes, materials, directions, values, etc. are merely examples for the purpose of easily understanding the present invention, and can be appropriately changed according to the application, purpose, specifications, etc.

[0010] [Pneumatic tires] A pneumatic tire 10 according to an example of the embodiment (hereinafter simply referred to as tire 10) will be described with reference to FIG.

[0011] The tire 10 of this embodiment is assumed to be a heavy-duty tire mounted on trucks, buses, etc. The tire 10 of this embodiment is assumed to be an all-weather tire that can be used throughout the year, from summer road surfaces to lightly snowy roads in winter. Furthermore, it is assumed that the tire 10 of this embodiment is equipped with tire chains as an anti-skid measure on snowy road surfaces or icy roads. With the tire 10, the rigidity of the shoulder blocks 12 can be maintained, as will be described in detail later, and the tire chains can be firmly fixed.

[0012] In the following, for ease of understanding, the tire 10 may be described according to the tire radial direction (arrow D in the figure), the tire axial direction (arrow W in the figure), and the tire circumferential direction (arrow R in the figure). Also, the tire radial direction or the tire axial direction may be described using the inside or outside.

[0013] The tire 10 includes a tread 11 disposed between a pair of tread ends. A plurality of main grooves are formed in the tread 11. The number of main grooves is not particularly limited, but in this embodiment, five main grooves are formed. The main grooves 21 formed on the outermost sides in the tire axial direction among the five main grooves are formed straight along the tire circumferential direction without bending in the tire axial direction. In addition, the main groove 22 formed in the approximate center (equator) in the tire axial direction among the five main grooves is formed to bend along the tire circumferential direction. Furthermore, main grooves 23 are also formed between the main grooves 21 and 22. By forming five main grooves, the drainage effect of the tire 10 can be improved.

[0014] In addition, the tread 11 is formed with a plurality of lateral grooves extending in a direction intersecting the main grooves. The plurality of lateral grooves include a lateral groove 31 extending from the main groove 21 toward the outside in the tire axial direction along the tire axial direction and communicating with the outer end in the tire axial direction, and a lateral groove 32 extending from the main groove 21 toward the inside in the tire axial direction or from the main groove 22 toward the outside in the tire axial direction. The lateral grooves enable stable running by firmly gripping the road surface. In addition, the lateral grooves can further improve the drainage effect of the main grooves described above.

[0015] When a tire chain is attached to the tire 10, the tire chain is attached to the tire 10 by engaging the tire chain with some of the lateral grooves 31. In this embodiment, the lateral grooves 31 define the shoulder blocks 12, but the lateral grooves of the present invention are not limited to this. The lateral grooves of the present invention may be notches or slits that communicate with the outer end of the tire in the axial direction.

[0016] The tread 11 has shoulder blocks 12 as shoulder land arranged on the outer side in the tire axial direction, and blocks 13 arranged between the shoulder blocks 12. The shoulder blocks 12 are defined by a main groove 21 and a lateral groove 31. The blocks 13 are defined by a main groove 23 and a lateral groove 32. In this embodiment, the shoulder land is the shoulder block 12, but the present invention is not limited thereto. The shoulder land of the present invention may be, for example, a shoulder rib.

[0017] The tire 10 includes a pair of sidewalls 14 that bulge outward in the tire axial direction, and a pair of beads 15. The beads 15 are fixed to the rim of a wheel, and include, for example, a bead core and a bead filler. The sidewalls 14 and the beads 15 are formed in an annular shape along the tire circumferential direction, and constitute the side surfaces of the tire 10. The sidewalls 14 are formed to extend in the tire radial direction from both ends of the tread 11 in the tire axial direction.

[0018] The tire 10 includes, for example, a carcass, a belt, and an inner liner. The carcass is a cord layer covered with rubber, and forms the framework of the tire 10 that can withstand loads, impacts, air pressure, and the like. The belt is a reinforcing band disposed between the carcass and the rubber that constitutes the tread 11. The belt tightly tightens the carcass to increase the rigidity of the tire 10. The inner liner is a rubber layer provided on the inner peripheral surface of the carcass, and maintains the air pressure of the tire 10.

[0019] [protrusion] The protrusion 40 as one example of the embodiment will be described with reference to FIGS.

[0020] As shown in Fig. 2, a protrusion 40 that protrudes axially outward is formed on the axially outer side surface of the shoulder block 12. The protrusions 40 are formed at each end of the shoulder block 12 in the tire circumferential direction, sandwiching the lateral groove 31. Here, the opposing side surfaces of the protrusions 40 sandwiching the lateral groove 31 are referred to as walls 40W. The wall 40W of the protrusion 40 and the inner side surface 31W of the lateral groove 31 (the side surface of the shoulder block 12 in the tire circumferential direction) may be formed continuously.

[0021] As described above, the lateral grooves 31 define the shoulder blocks 12 and communicate with the outer ends in the axial direction of the tire. When viewed from the circumferential direction of the tire, the bottom surface 31A of the lateral groove 31 is formed in an arc shape that extends radially inwardly in the tire direction as it moves axially outwardly (see FIG. 11). Hereinafter, the arc-shaped portion of the bottom surface 31A is referred to as an inclined portion 31B. When a tire chain is engaged with the lateral groove 31, the tire chain is engaged along the inclined portion 31B.

[0022] The distance from the radial end face of the shoulder block 12 (the surface of the tread 11) to the bottom face 31A of the lateral groove 31 is defined as the "radial depth of the tire." Meanwhile, the distance from the axial end face of the protrusion 40 to the bottom face 31A (inclined portion 31B) of the lateral groove 31 is defined as the "axial depth of the tire."

[0023] According to the protrusion 40, when the tire chain is engaged with the lateral groove 31 sandwiched between the protrusions 40, the "tire axial depth" of the lateral groove 31 is deepened, making it difficult for the tire chain to come off the axial outer end of the lateral groove 31, and the tire chain can be firmly fixed to the tire 10.

[0024] As shown in Fig. 3, a shoulder rib 51 may be formed as the shoulder land. A notch 52 may be formed in the shoulder rib 51. In this case, the protrusion 40 may be formed on the axially outer surface of the shoulder rib 51 so as to protrude outward in the tire axial direction. The protrusions 40 are formed at each of the circumferential ends of the tire that sandwich the notch 52.

[0025] 4, the protrusions 40 are formed at the circumferential ends of the shoulder blocks 12 that sandwich at least one of two circumferentially adjacent lateral grooves 31. In other words, the protrusions 40 are formed at the circumferential ends of the shoulder blocks 12 that sandwich every other lateral groove 31 along the circumferential direction of the tire.

[0026] With the above configuration, when the tire chain is attached to the tire 10, the tire chain can be easily engaged with the lateral groove 31. As a result, when the tire chain is attached to the tire 10, the tire chain can be firmly fixed to the tire 10.

[0027] [Tire radial protrusion formation position] 2 again, the position where the protrusion 40 is formed in the shoulder block 12 will be described. When the shallowest depth of the "tire radial depth" of the lateral groove 31 is L1 and the distance from the tire radial end face of the shoulder block 12 to the tire radial outer end of the protrusion 40 in the tire radial direction is L2, the protrusion 40 is formed so as to satisfy L1>L2.

[0028] In other words, when a tire chain is engaged with the lateral groove 31 sandwiched between the protrusions 40, the protrusions 40 are positioned radially outward of the lower end of the tire chain engaged with the shallowest part of the lateral groove 31. This makes it difficult for the tire chain engaged with the inclined part 31B (the outer end of the lateral groove 31 in the tire axial direction) of the lateral groove 31 sandwiched between the protrusions 40 to come off the lateral groove 31, and the tire chain can be firmly fixed to the tire 10.

[0029] In addition, the protrusions 40 are formed such that the inner end in the tire radial direction of the protrusions 40 is located radially inward of the inner end in the tire radial direction of the lateral grooves 31. This makes it difficult for the tire chain engaged with the inclined portion 31B (the outer end in the tire axial direction of the lateral grooves 31) of the lateral grooves 31 sandwiched between the protrusions 40 to come off from the lateral grooves 31, and allows the tire chain to be firmly fixed to the tire 10.

[0030] [Radial thickness of protrusion] The thickness of the protrusion 40 in the tire radial direction will be described with reference to Fig. 2. The protrusion 40 is formed so that when the protrusion 40 is divided into an outer portion and an inner portion in the tire radial direction, the average thickness of the outer portion is greater than the average thickness of the inner portion. For example, the outer portion in the tire radial direction of the protrusion 40 in this embodiment is formed of a first inclined portion 40A formed at an incline from the shoulder block 12 to a predetermined thickness, and a flat portion 40B having a predetermined thickness. On the other hand, the inner portion in the tire radial direction is formed of a second inclined portion 40C formed at an incline from the shoulder block 12 to a predetermined thickness.

[0031] The above configuration can deepen the "tire axial depth" of the inclined portion 31B of the lateral groove 31 sandwiched between the protrusions 40. This makes it difficult for the tire chain engaged with the inclined portion 31B (the axial outer end of the lateral groove 31) of the lateral groove 31 sandwiched between the protrusions 40 to come off the lateral groove 31, and allows the tire chain to be firmly fixed to the tire 10.

[0032] [Circumferential thickness of protrusion] The thickness of the protrusion 40 in the tire circumferential direction will be described with reference to Figures 5 to 10. For example, as shown in Figure 5, the protrusion 40 is formed so that its thickness increases toward the lateral groove 31 in the tire circumferential direction.

[0033] The above configuration allows the thickness of the wall 40W adjacent to the lateral groove 31 to be maximized. This allows the thickness of only the portion where the tire chain engages to be maximized. In other words, a shape that achieves the effect of the protrusion 40 can be realized with a small amount of material.

[0034] [Opening angle of the wall with the horizontal groove in between] For example, as shown in Fig. 5, the protrusion 40 is formed with an inclination such that the interval between the walls 40W increases toward the outside in the tire axial direction when viewed from the tire radial direction. More specifically, the walls 40W of the protrusion 40 are formed with an inclination of θ1 from the tire axial direction toward the outside of the lateral groove 31 in the tire circumferential direction. Note that the protrusion 40 illustrated in Fig. 5 is formed with a gentle inclination with respect to the outer surface of the shoulder block 12 in the tire axial direction, but the protrusion of the present invention is not limited thereto. For example, the protrusion may be formed with a step with respect to the outer surface of the shoulder block in the tire axial direction.

[0035] The above configuration makes it easy to engage the tire chain with the lateral groove 31 formed adjacent to the protrusion 40. This makes it easier to install the tire chain. The above configuration also makes it possible to prevent damage to the protrusion 40 when the corner of the protrusion 40 hits a curbstone or the like. Furthermore, the above configuration makes it difficult for the tire chain to hit the corner of the protrusion 40 when the tire chain is installed on the tire 10. This makes it possible to prevent damage to the protrusion 40.

[0036] For example, as shown in FIG. 6, the protrusion 40 may be formed in a trapezoidal shape that is inclined, for example, by θ1 from the tire axial direction from the lateral groove 31 in the tire circumferential direction toward the outside when viewed in the tire radial direction, forms a flat portion, and is further inclined to the shoulder block 12.

[0037] For example, as shown in FIG. 7, the protrusion 40 may be formed in a trapezoidal shape inclined, for example, by θ1 from the tire axial direction from the lateral groove 31 in the tire circumferential direction toward the outside when viewed in the tire radial direction, forming a flat portion, and further inclined, for example, by θ1 from the tire axial direction to the adjacent lateral groove 31.

[0038] The walls 40W facing each other across the lateral groove 31 at the inner portion in the tire radial direction of the protrusion 40 shown in Fig. 8(B) are formed so that the distance between the walls 40W increases toward the outside in the tire axial direction as viewed from the tire radial direction, compared to the walls 40W facing each other across the lateral groove 31 at the outer portion in the tire radial direction of the protrusion 40 shown in Fig. 8(A). More specifically, the walls 40W at the outer portion in the tire radial direction of the protrusion 40 shown in Fig. 8(A) are formed inclined by θ1 from the tire axial direction toward the outside of the lateral groove 31 in the tire circumferential direction, and the walls 40W at the inner portion in the tire radial direction of the protrusion 40 shown in Fig. 8(B) are formed inclined by θ2 from the tire axial direction toward the outside of the lateral groove 31 in the tire circumferential direction, satisfying the relationship θ2>θ1.

[0039] With the above configuration, play (gap) is generated between the wall 40W of the protrusion 40 and the tire chain in areas other than the inclined portion 31B of the lateral groove 31. This makes it possible to suppress damage when the chain sags and loosens at the contact area of ​​the tire 10 and hits the protrusion.

[0040] 9, the walls 40W of the protrusions 40 are formed to be inclined toward the outside of the lateral grooves 31 in the tire circumferential direction. In this case, the walls 40W may be formed to be bent and inclined when viewed from the tire radial direction. In other words, the protrusions 40 may be formed to be inclined so that the interval between the walls 40W increases in two stages as it goes toward the outside in the tire axial direction when viewed from the tire radial direction.

[0041] For example, as shown in FIG. 10, the protrusion 40 may be formed in a trapezoidal shape in which the spacing between the walls 40W increases in two stages as it moves outward in the tire axial direction as viewed from the tire radial direction, forming a flat portion, and further inclining to the shoulder block 12.

[0042] [Relationship between protrusions and tire chain wire diameter] The relationship between the projection 40 and the wire diameter of the tire chain will be described with reference to Fig. 11. As described above, the inclined portion 31B of the lateral groove 31 is formed in an arc shape in a cross section seen from the tire circumferential direction. In addition, in the normal direction of the arc shape of the inclined portion 31B of the lateral groove 31, the maximum value of the distance L3 between the bottom surface 31A (inclined portion 31B) of the lateral groove 31 and the surface of the projection 40 is 2 / 3 or more of the wire diameter of the tire chain to be mounted.

[0043] With the above configuration, the tire chain engaged with the inclined portion 31B (the axially outer end of the lateral groove 31) of the lateral groove 31 sandwiched between the protrusions 40 is less likely to come off the inclined portion 31B, and the tire chain can be firmly fixed to the tire 10.

[0044] [summary] The present disclosure is further illustrated by the following embodiments. Configuration 1: A pneumatic tire having a tread, The tread has a shoulder land disposed on an outer side in the tire axial direction, A lateral groove is formed on the shoulder land, the lateral groove being connected to the axially outer end of the tire. A protrusion is formed on an outer surface of the shoulder land in the tire axial direction, the protrusion protruding toward the outside in the tire axial direction, The protrusions are formed at the ends of the shoulder land in the tire circumferential direction on either side of the lateral groove. Pneumatic tires. Configuration 2: A pneumatic tire according to configuration 1, When the shallowest depth of the lateral groove in the tire radial direction is L1 and the distance from the end surface of the shoulder land to the protrusion in the tire radial direction is L2, L1>L2 is satisfied. Pneumatic tires. Configuration 3: A pneumatic tire according to configuration 1 or 2, In the tire radial direction, an inner end of the protrusion is formed more inward than an inner end of the lateral groove. Pneumatic tires. Configuration 4: A pneumatic tire according to any one of configurations 1 to 3, When the protrusion is divided into an outer portion and an inner portion in the tire radial direction, the average thickness of the outer portion is greater than the average thickness of the inner portion. Pneumatic tires. Configuration 5: A pneumatic tire according to any one of configurations 1 to 4, The protrusion has a thickness increasing toward the lateral groove in the tire circumferential direction. Pneumatic tires. Configuration 6: A pneumatic tire according to any one of configurations 1 to 5, Walls of the projections facing each other across the lateral groove are inclined such that the distance between the walls increases toward the outside in the tire axial direction when viewed in the tire radial direction. Pneumatic tires. Configuration 7: A pneumatic tire according to any one of configurations 1 to 6, a distance between walls facing each other across the lateral groove at an inner portion of the protrusion in the tire radial direction increases toward the outer side in the tire axial direction as viewed from the tire radial direction, compared to a distance between walls facing each other across the lateral groove at an outer portion of the protrusion in the tire radial direction, Pneumatic tires. Configuration 8: A pneumatic tire according to any one of configurations 1 to 7, The protrusions are formed on both sides in the tire circumferential direction of at least one of the two lateral grooves adjacent to each other in the tire circumferential direction. Pneumatic tires. Configuration 9: A pneumatic tire according to any one of configurations 1 to 8, A bottom surface of the lateral groove is formed in an arc shape when viewed from the tire circumferential direction, The maximum value of the distance L3 between the bottom surface of the lateral groove and the surface of the protrusion in the normal direction of the arc shape of the bottom surface is 2 / 3 or more of the wire diameter of the tire chain to be attached. Pneumatic tires.

[0045] It should be noted that the present invention is not limited to the above-described embodiment and its modified examples, and various modifications and improvements are possible within the scope of the matters described in the claims of this application. [Explanation of symbols]

[0046] 10 tire (pneumatic tire), 11 tread, 12 shoulder block (shoulder land), 13 block, 14 sidewall, 15 bead, 21 main groove, 22 main groove, 23 main groove, 31 lateral groove, 31A bottom surface, 31B inclined portion, 31W inner surface, 32 lateral groove, 40 protrusion, 40A first inclined portion, 40B flat portion, 40C second inclined portion, 40W wall,

Claims

1. A pneumatic tire having a tread, The tread has a shoulder land disposed on an outer side in the tire axial direction, A lateral groove is formed on the shoulder land, the lateral groove being connected to the axially outer end of the tire. A protrusion is formed on an outer surface of the shoulder land in the tire axial direction, the protrusion protruding toward the outside in the tire axial direction, The protrusions are formed at the ends of the shoulder land in the tire circumferential direction on either side of the lateral groove. Pneumatic tires.

2. 2. The pneumatic tire according to claim 1, When the shallowest depth of the lateral groove in the tire radial direction is L1 and the distance from the end surface of the shoulder land to the protrusion in the tire radial direction is L2, L1>L2 is satisfied. Pneumatic tires.

3. 3. The pneumatic tire according to claim 2, In the tire radial direction, an inner end of the protrusion is formed more inward than an inner end of the lateral groove. Pneumatic tires.

4. 4. The pneumatic tire according to claim 3, When the projection is divided into an outer portion and an inner portion in the tire radial direction, an average thickness of the outer portion is greater than an average thickness of the inner portion. Pneumatic tires.

5. 4. The pneumatic tire according to claim 3, The protrusion has a thickness increasing toward the lateral groove in the tire circumferential direction. Pneumatic tires.

6. 4. The pneumatic tire according to claim 3, Walls of the projections facing each other across the lateral groove are inclined such that the distance between the walls increases toward the outside in the tire axial direction when viewed in the tire radial direction. Pneumatic tires.

7. 7. The pneumatic tire according to claim 6, the walls facing each other across the lateral groove at an inner portion of the protrusion in the tire radial direction have a distance therebetween that increases toward the outside in the tire axial direction as viewed from the tire radial direction, compared to the walls facing each other across the lateral groove at an outer portion of the protrusion in the tire radial direction. Pneumatic tires.

8. A pneumatic tire according to any one of claims 1 to 7, the protrusions are formed on both sides in the tire circumferential direction of at least one of the two lateral grooves adjacent to each other in the tire circumferential direction, Pneumatic tires.

9. A pneumatic tire according to any one of claims 1 to 7, A bottom surface of the lateral groove is formed in an arc shape when viewed from the tire circumferential direction, The maximum value of the distance L3 between the bottom surface of the lateral groove and the surface of the protrusion in the normal direction of the arc shape of the bottom surface is 2 / 3 or more of the wire diameter of the tire chain to be attached. Pneumatic tires.

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