Tire

Abstract

To reduce vehicle exterior noise outside a vehicle, while suppressing steering stability performance from deteriorating.SOLUTION: A tire 1 includes a shoulder block row 4. In the shoulder block row 4, a plurality of shoulder lateral grooves 6 and a plurality of shoulder blocks 7 are arranged alternately. The plurality of shoulder blocks 7 respectively are partitioned by dividing grooves 8 into outer block pieces 9 in a tire axial direction and inner block pieces 10 in the tire axial direction. The shoulder lateral groove 6 is provided with a tie-bar 12 having a groove bottom 6s locally raised. The tie-bar 12 joints at least three block pieces 9 and 10 of four block pieces 9 and 10 facing the shoulder lateral grooves 6 to one another.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] The following Patent Document 1 describes a tire including a first inclined groove inclined from a first tread end toward the tire equator, a second inclined groove inclined from a second tread end toward the tire equator, and a first longitudinal groove connecting adjacent first inclined grooves in the tire circumferential direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-1120 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in line with the growing interest in environmental issues, there has been a demand for reducing external noise, particularly pitch noise. Pitch noise occurs when blocks, which are discontinuous parts of the tread in the circumferential direction of the tire, receive an impact when the block hits the ground, and the impact force causes the tread and sidewall to vibrate and emit noise. In particular, the shoulder land portion of the tread is considered to contribute greatly to pitch noise.

[0005] In order to reduce the pitch noise, for example, it is conceivable to reduce the rigidity of the shoulder blocks arranged in the shoulder land portions. However, simply reducing the rigidity of the shoulder land portions causes a problem in that the steering stability performance is deteriorated.

[0006] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire that is capable of reducing external noise while suppressing deterioration of steering stability. [Means for solving the problem]

[0007] The present invention relates to a tire having a tread portion, the tread portion including a shoulder block row, the shoulder block row including a plurality of shoulder lateral grooves and a plurality of shoulder blocks arranged alternately in the tire circumferential direction, each of the plurality of shoulder blocks being divided into an axially outer block piece and an axially inner block piece by a dividing groove extending in the tire circumferential direction, and at least one of the plurality of shoulder lateral grooves is provided with a tie bar that locally raises the groove bottom, The tie bar is a tire that connects at least three block pieces among four block pieces facing the at least one shoulder lateral groove. Effect of the Invention

[0008] By employing the above-mentioned configuration, the tire of the present invention can reduce external noise while suppressing deterioration of steering stability. [Brief description of the drawings]

[0009] [Figure 1] 1 is a partial plan view of a tread portion showing one embodiment of a tire of the present invention. [Diagram 2] FIG. 2 is a perspective cross-sectional view of FIG. [Diagram 3] 2A is a plan view of a shoulder block row, and FIG. 2B is a cross-sectional view taken along line AA of FIG. [Figure 4] FIG. 4 is a plan view of a shoulder block row. [Diagram 5] FIG. 4 is a plan view of a shoulder block row. [Figure 6] FIG. [Figure 7] FIG. 11 is a perspective cross-sectional view of a shoulder block row according to another embodiment. [Figure 8] FIG. 11 is a plan view of a shoulder block row according to still another embodiment. [Figure 9]9(A) is a perspective cross-sectional view of the shoulder block row in FIG. 8, and FIG. 9(B) is a cross-sectional view taken along line BB in FIG. [Figure 10] FIG. 11 is a perspective cross-sectional view of a shoulder block row according to still another embodiment. [Figure 11] FIG. 11 is a plan view of a tread portion of still another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings include exaggerated expressions and expressions different from the dimensional ratio of the actual structure in order to facilitate understanding of the present invention. In addition, when there are multiple embodiments, the same or common elements are given the same reference numerals throughout the specification, and duplicated explanations are omitted.

[0011] Fig. 1 is a partial plan view of a tread portion 2 of a tire 1 showing one embodiment of the present invention. Fig. 2 is a perspective cross-sectional view of the tread portion 2 shown in Fig. 1. The tire 1 of this embodiment is suitably used, for example, as a pneumatic tire for a passenger vehicle, and more specifically, as a four-wheel drive tire 1 capable of running on muddy ground. However, the present invention may also be used, for example, in a pneumatic tire for heavy loads and a non-pneumatic tire that is not filled with compressed air.

[0012] In this specification, unless otherwise specified, the dimensions of each part of the tire 1 are values ​​measured in a normal state. In the case of a pneumatic tire for which various standards are established, the "normal state" refers to a state in which the tire 1 is mounted on a normal rim (not shown), inflated to a normal internal pressure, and unloaded. In the case of a tire for which various standards are not established, the normal state refers to a standard usage state according to the intended use of the tire, which is a state in which the tire is not mounted on a vehicle and is unloaded.

[0013] The "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based, for example, "standard rim" in the case of JATMA, "Design Rim" in the case of TRA, and "Measuring Rim" in the case of ETRTO.

[0014] The "normal internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standard on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0015] As shown in Figures 1 and 2, the tread portion 2 includes a shoulder block row 4. The shoulder block row 4 has a plurality of shoulder lateral grooves 6 and a plurality of shoulder blocks 7 arranged alternately in the tire circumferential direction. Each of the shoulder blocks 7 is divided into an axially outer block piece 9 and an axially inner block piece 10 by a dividing groove 8 extending in the tire circumferential direction. Such a dividing groove 8 reduces the rigidity of each shoulder block 7. Therefore, the tire 1 of this embodiment can reduce pitch noise caused by the shoulder block row 4, and ultimately reduce external vehicle noise.

[0016] At least one of the shoulder lateral grooves 6 is provided with a tie bar 12 that locally raises the groove bottom 6s. The tie bar 12 connects at least three of the four block pieces 9, 10 that face at least one shoulder lateral groove 6, and in this embodiment, three block pieces 9, 10, 10. In other words, the tie bar 12 connects the block pieces 9, 9 or 10, 10 adjacent to each other in the tire circumferential direction, and the block pieces 9, 10 adjacent to each other in the tire axial direction. Therefore, the tie bar 12 suppresses deformation of each block piece 9, 10 in the tire circumferential direction and the tire axial direction, thereby maintaining high stability and operability during cornering and straight running. Therefore, the tire 1 of this embodiment can reduce outside noise while suppressing deterioration of steering stability.

[0017] Fig. 3(A) is a plan view of the shoulder block row 4, and Fig. 3(B) is a cross-sectional view taken along line AA of Fig. 3(A). As shown in Fig. 3, the tie bar 12 includes a top surface 14 facing outward in the tire radial direction. The top surface 14 includes an inner end 14i in the tire axial direction, an outer end 14e in the tire axial direction, and a pair of side edges 14s extending along the shoulder lateral groove 6. The inner end 14i and the outer end 14e connect both ends of the pair of side edges 14s. The pair of side edges 14s are edges where the top surface 14 and the shoulder lateral groove 6 intersect. The tie bar 12 further includes an inner side surface 17 and an outer side surface 18 (shown in Fig. 2) extending inward in the tire radial direction from the inner end 14i and the outer end 14e, respectively.

[0018] In this embodiment, the top surface 14 extends parallel to the tread surface 7a of the shoulder block 7. In other words, the groove depth D1a of the shoulder lateral groove 6 is the same on the top surface 14 of the tie bar 12. This allows the rigidity of the tie bar 12 to be uniform.

[0019] Each of the inner end 14i and the outer end 14e is inclined at an angle θa of 10 to 60° with respect to the tire circumferential direction. Such inner end 14i and outer end 14e have an edge component in the tire axial direction and an edge component in the tire circumferential direction, and exert snow column shear force in the tire circumferential direction and the tire axial direction, improving snow performance. In this embodiment, the angle θa of each of the inner end 14i and the outer end 14e is set to be the same as the angle θ2 of the dividing groove 8 to which the tie bar 12 is connected with respect to the tire circumferential direction. It is presumed that this suppresses deformation (movement) of the dividing groove 8 of the inner block piece 9 and the outer block piece 10 in the width direction. For example, the inner end 14i and the outer end 14e are inclined in the same direction with respect to the tire circumferential direction.

[0020] The axial length La of the tie bar 12 is preferably at least three times the groove width W2 of the dividing groove 8, more preferably at least 3.5 times, more preferably at most 5 times, and even more preferably at most 4.5 times. Since the axial length La of the tie bar 12 is at least three times the groove width W2 of the dividing groove 8, it is possible to suppress deformation of each block piece 9, 10. Since the axial length La of the tie bar 12 is at most five times the groove width W2 of the dividing groove 8, it is possible to reduce the rigidity of the shoulder block 7.

[0021] In this embodiment, the raised height Ha of the tie bar 12 is desirably 10% or more of the maximum block height Hx (shown in FIG. 2) of the shoulder block 7, more desirably 20% or more, more desirably 50% or less, and even more desirably 30% or less. Since the raised height Ha of the tie bar 12 is 10% or more of the maximum block height Hx of the shoulder block 7, an effect of suppressing deformation of each block piece 9, 10 is exerted. Since the raised height Ha of the tie bar 12 is 50% or less of the maximum block height Hx of the shoulder block 7, the rigidity of the shoulder block 7 can be effectively reduced, and an effect of reducing external noise is exerted.

[0022] In this embodiment, the shoulder block row 4 includes the tread end Te. In other words, the shoulder block row 4 is located at the axially outermost position of the tread portion 2. The "tread end Te" is the axially outermost ground contact position when the tire 1 in the normal state is placed on a flat surface with a normal load and a camber angle of 0°. The axial distance between the axially opposite tread ends Te, Te is the tread width TW (shown in FIG. 6).

[0023] The "normal load" is a load determined for each tire 1 by each standard in a standard system including the standard on which the tire 1 is based, and is the "maximum load capacity" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "LOAD CAPACITY" in the case of ETRTO.

[0024] FIG. 4 is a plan view of the shoulder block row 4. As shown in FIG. 4, in this embodiment, the shoulder blocks 7 include a first shoulder block 7A and a second shoulder block 7B adjacent to the first shoulder block 7A in the tire circumferential direction. The maximum length L1 in the tire axial direction of the first shoulder block 7A is formed to be greater than the maximum length L2 in the tire axial direction of the second shoulder block 7B, for example. The first shoulder block 7A and the second shoulder block 7B are, for example, arranged alternately in the tire circumferential direction. Note that the shoulder block 7 is not limited to this form. In order to reduce external noise while suppressing deterioration of steering stability performance, the length L1 of the first shoulder block 7A and the length L2 of the second shoulder block 7B are preferably 20% or more of the tread width TW, more preferably 25% or more, more preferably 40% or less, and even more preferably 35% or less.

[0025] The first shoulder block 7A and the second shoulder block 7B each include an outer block piece 9 and an inner block piece 10. The outer block piece 9 and the inner block piece 10 of the first shoulder block 7A are referred to as a first outer block piece 9A and a first inner block piece 10A, respectively. The outer block piece 9 and the inner block piece 10 of the second shoulder block 7B are referred to as a second outer block piece 9B and a second inner block piece 10B, respectively. In this embodiment, the first outer block piece 9A, the first inner block piece 10A, and the second inner block piece 10B are connected by a tie bar 12. Note that the first outer block piece 9A, the second outer block piece 9B, and the second inner block piece 10B may be connected to the tie bar 12 (not shown).

[0026] The shoulder lateral grooves 6 are connected to the tread edge Te. In this embodiment, the shoulder lateral grooves 6 include an outer groove portion 6A that is connected to the tread edge Te, and an inner groove portion 6B that is connected to the outer groove portion 6A and inclined at an angle θ1 with respect to the tire circumferential direction smaller than that of the outer groove portion 6A. Such shoulder lateral grooves 6 can disrupt and reduce pitch noise passing through the grooves. In this embodiment, the outer groove portion 6A extends parallel to the tire axial direction. The inner groove portion 6B has an angle θ1 with respect to the tire axial direction of 10 to 30°, for example.

[0027] The shoulder lateral grooves 6 include, for example, a first shoulder lateral groove 15 having a larger axial length and a second shoulder lateral groove 16 having a smaller axial length than the first shoulder lateral groove 15. In this embodiment, the first shoulder lateral grooves 15 and the second shoulder lateral grooves 16 are provided alternately in the circumferential direction of the tire. In this embodiment, a tie bar 12 is provided in the second shoulder lateral groove 16, and no tie bar 12 is provided in the first shoulder lateral groove 15. Note that the tie bar 12 may be provided in the first shoulder lateral groove 15.

[0028] Although not particularly limited, the groove width W1 of the shoulder lateral groove 6 is, for example, desirably 5% or more of the maximum axial length L1 of the first shoulder block 7A, more desirably 7% or more, desirably 12% or less, and even more desirably 10% or less.

[0029] The dividing groove 8 extends, for example, in a straight line. The dividing groove 8 is formed with a groove width W2 (shown in FIG. 3(A)) smaller than that of the shoulder lateral groove 6. Such a dividing groove 8 prevents an excessive decrease in the rigidity of the shoulder block 7. The groove width W2 of the dividing groove 8 is preferably 40% or more of the groove width W1 of the shoulder lateral groove 6, more preferably 45% or more, more preferably 60% or less, and even more preferably 55% or less.

[0030] FIG. 5 is a plan view of the shoulder block row 4. As shown in FIG. 5, the dividing groove 8 includes a first dividing groove 8A arranged in the first shoulder block 7A and a second dividing groove 8B arranged in the second shoulder block 7B. The axial positional deviation Ly between the end 13a of the first dividing groove 8A on the first tire circumferential direction f1 side (lower side in the figure) and the end 13b of the second dividing groove 8B on the second tire circumferential direction f2 side (upper side in the figure) is preferably 5% to 50% of the maximum axial length Lx of each block piece 9, 10. Such a positional deviation Ly can efficiently divide the pitch noise passing through the shoulder lateral groove 6 into the first dividing groove 8A and the second dividing groove 8B, thereby reducing the pitch noise. The second tire circumferential direction f2 is opposite to the first tire circumferential direction f1. The end 13a and the end 13b are ends on the groove center line 8c of each dividing groove 8A, 8B.

[0031] As shown in Fig. 3(A), the dividing groove 8 is inclined with respect to the tire circumferential direction. Since such a dividing groove 8 has an edge component in the tire circumferential direction and an edge component in the tire axial direction, it is possible to exert a snow column shear force during straight running and cornering. Although not particularly limited, the angle θ2 of the dividing groove 8 with respect to the tire circumferential direction is preferably 10° or more, more preferably 20° or more, preferably 80° or less, and even more preferably 70° or less.

[0032] As shown in Fig. 3(B), the groove depth D2 of the dividing groove 8 is preferably smaller than the groove depth D1 of the shoulder lateral groove 6. This further suppresses excessive reduction in rigidity of the shoulder block 7. In order to simultaneously improve exterior noise and suppress reduction in steering stability performance, the groove depth D2 of the dividing groove 8 is preferably 40% or more of the groove depth D1 of the shoulder lateral groove 6, more preferably 45% or more, more preferably 60% or less, and even more preferably 55% or less. In this embodiment, the groove depth D1 of the shoulder lateral groove 6 is the same as the maximum block height Hx of the shoulder block 7.

[0033] As shown in Fig. 5, the outer block piece 9 and the inner block piece 10 are each provided with a sipe 31. Such sipes 31 can reduce the impact force of each block piece 9, 10 when the block piece 9, 10 touches the ground, thereby reducing pitch noise generated in each block piece 9, 10. In this specification, a sipe is a notched recessed portion having a width of less than 1.5 mm, and is clearly distinguished from a groove, which is a recessed portion having a groove width of 1.5 mm or more. The grooves include shoulder lateral grooves 6, dividing grooves 8, etc.

[0034] The sipes 31 include outer sipes 31a arranged in the outer block piece 9 and inner sipes 31b arranged in the inner block piece 10. At least one sipe, 31b, and two sipes in this embodiment, are provided in each of the block pieces 9 and 10. The outer sipes 31a and the inner sipes 31b extend from the dividing groove 8 and terminate within each of the block pieces 9 and 10, for example.

[0035] In this embodiment, the outer sipes 31a and the inner sipes 31b extend so as to be formed on one imaginary straight line v. Such outer sipes 31a and inner sipes 31b come into contact with the ground at almost the same time, and the impact force at the time of contact can be significantly reduced. "Formed on the imaginary straight line v" means that the maximum separation distance Lb in the tire circumferential direction between the imaginary straight line v obtained by extending the width center line 31c of the outer sipe 31a toward the inner block piece 10 side and the width center line 31d of the inner sipe 31b is 3 mm or less.

[0036] The angle θ3 of the sipe 31 with respect to the tire circumferential direction is, for example, 10 to 80°. In this embodiment, the length Lc of the sipe 31 in the tire axial direction is 20% to 80% of the maximum length Lt in the tire axial direction of the block pieces 9, 10 in which the sipe 31 is formed.

[0037] FIG. 6 is a plan view of the tread portion 2 of this embodiment. As shown in FIG. 6, the tread portion 2 includes, for example, a crown block row 5 located closer to the tire equator C than the shoulder block row 4. The tread portion 2 of this embodiment includes a pair of crown block rows 5 located on both sides of the tire equator C, and a pair of shoulder block rows 4 located outside each crown block row 5 in the tire axial direction. In this embodiment, the tread portion 2 has a point-symmetric pattern centered on an arbitrary point on the tire equator C. The tread portion 2 may have an axisymmetric pattern with respect to the tire equator C, or may have an asymmetric pattern.

[0038] The crown block row 5 includes a plurality of crown lateral grooves 21 and a plurality of crown blocks 22 arranged alternately in the tire circumferential direction. The crown block 22 is divided into a first block piece 22A on the first tire circumferential direction f1 side and a second block piece 22B on the second tire circumferential direction f2 side by a crown dividing groove 23 extending in the tire axial direction.

[0039] Each of the block pieces 22A, 22B is provided with, for example, a plurality of crown sipes 32 extending in the tire axial direction. The crown sipes 32 cushion the impact that each of the block pieces 22A, 22B receives when it comes into contact with the ground, thereby reducing pitch noise.

[0040] In this embodiment, the crown lateral grooves 21 are inclined with respect to the tire circumferential direction. The crown dividing grooves 23 are, for example, inclined in the opposite direction to the crown lateral grooves 21 with respect to the tire circumferential direction. The groove width W5 of the crown lateral grooves 21 is larger than the groove width W1 of the shoulder lateral grooves 6. The groove width W6 of the crown dividing grooves 23 is 0.4 to 0.6 times the groove width W5 of the crown lateral grooves 21. The form of the crown block row 5 is not limited to the form shown in the drawings.

[0041] Fig. 7 is a perspective cross-sectional view of a shoulder block row 4 of another embodiment. As shown in Fig. 7, in this embodiment, a tie bar 12 connects four block pieces 9, 10 facing at least one shoulder lateral groove 6. Such a tie bar 12 further suppresses deformation of each block piece 9, 10 in the tire circumferential direction and the tire axial direction, thereby improving steering stability. In this embodiment, a top surface 14 of the tie bar 12 extends parallel to the tread surface 7a of the shoulder block 7.

[0042] Fig. 8 is a plan view of a shoulder block row 4 in still another embodiment. Fig. 9(A) is a perspective cross-sectional view of the shoulder block row 4 in Fig. 8, and Fig. 9(B) is a cross-sectional view taken along line BB in Fig. 8. As shown in Figs. 8 and 9, in this embodiment, the tie bar 12 includes an inner portion 27 that connects two inner block pieces 10, 10 facing at least one shoulder lateral groove 6 and one outer block piece 9. In this embodiment, the inner portion 27 connects a first outer block piece 9A, a first inner block piece 10A, and a second inner block piece 10B.

[0043] The inner portion 27 has an inner top surface 28 facing outward in the tire radial direction. The inner top surface 28 includes an inner end 28i and an outer end 28e in the tire axial direction.

[0044] The inner top surface 28 descends toward the first tire circumferential direction f1. This inner top surface 28 maintains high deformation between the outer block piece 9 and the inner block piece 10 adjacent in the tire axial direction, and ensures groove volume on the first tire circumferential direction f1 side of the shoulder lateral groove 6 to exert a large snow column shear force. In this embodiment, the inner top surface 28 descends toward the second inner block piece 10B. This inner portion 27 maintains a high effect of suppressing deformation of the first outer block piece 9A and the first inner block piece 10A, and further reduces the impact force of the second inner block piece 10B when it comes into contact with the ground.

[0045] The tie bar 12 includes an outer portion 29 connecting two outer block pieces 9, 9 facing at least one shoulder lateral groove 6 and one inner block piece 10. In this embodiment, the outer portion 29 connects the second outer block piece 9B, the second inner block piece 10B, and the first outer block piece 9A. The outer portion 29 has an outer top surface 30 facing outward in the tire radial direction. The outer top surface 30 descends toward the second tire circumferential direction f2. In this way, the outer top surface 30 descends in the opposite direction to the inner top surface 28, so that the deformation of the first shoulder block 7A and the second shoulder block 7B can be made to be the same, and therefore deterioration of steering stability can be further suppressed. In this embodiment, the outer top surface 30 descends toward the first outer block piece 9A. Such an outer portion 29 maintains a high effect of suppressing deformation of the second outer block piece 9B and the second inner block piece 10B, and also reduces the impact force of the first outer block piece 9A when the first outer block piece 9A touches the ground, thereby enhancing the effect of reducing noise outside the vehicle. The outer top surface 30 includes an inner end 30i and an outer end 30e in the tire axial direction.

[0046] In this embodiment, the tie bar 12 is integrally formed with an inner portion 27 and an outer portion 29. This further suppresses deformation of each block piece 9A, 9B, 10A, and 10B. In this embodiment, the inner top surface 28 and the outer top surface 30 are connected so that the outer end 28e and the inner end 30i intersect.

[0047] The maximum raised height Ho of the outer portion 29 is desirably greater than the maximum raised height Hi of the inner portion 27. This makes it possible to effectively reduce the pitch noise passing through the shoulder lateral grooves 6 in the outer portion 29 adjacent to the tread edge Te.

[0048] The maximum raised height Hs of the tie bar 12, at which the top surface 14 descends, is preferably 10% or more of the maximum block height Hx (shown in FIG. 2) of the shoulder block 7. This reliably suppresses deformation of each block piece 9, 10. Furthermore, if the maximum raised height Hs is excessively large, it is not possible to reduce the impact sound at the time of contact with the ground, and it is not possible to reduce noise outside the vehicle. For this reason, the maximum raised height Hs is more preferably 20% or more of the maximum block height Hx of the shoulder block 7, more preferably 60% or less, and even more preferably 70% or less.

[0049] In terms of the area of ​​each tread surface 7a of the shoulder blocks 7, the sum Sa of the three block pieces connected by the outer portion 29 is preferably 80% or more, more preferably 90% or more, more preferably 120% or less, and even more preferably 110% or less of the sum Sb of the three block pieces connected by the inner portion 27. The sum Sa is the sum of the two outer block pieces 9, 9 and one inner block piece 10, and in this embodiment, is the sum of the areas of the tread surfaces of the first outer block piece 9A, the second outer block piece 9B, and the second inner block piece 10B. The sum Sb is the sum of the two inner block pieces 10, 10 and one outer block piece 9, and in this embodiment, is the sum of the areas of the tread surfaces of the first outer block piece 9A, the first inner block piece 10A, and the second inner block piece 10B.

[0050] FIG. 10 is a perspective view of a shoulder block row 4 of yet another embodiment. As shown in FIG. 10, in this embodiment, the tie bar 12 includes an inner portion 27 and an outer portion 29, and the inner portion 27 and the outer portion 29 are formed separately. In this embodiment, the inner end 30i of the outer top surface 30 of the outer portion 29 and the outer end 28e of the inner top surface 28 of the inner portion 27 are arranged to be separated in the tire axial direction via the groove bottom 6s. Even in this embodiment, the deformation of the first outer block piece 9A, the first inner block piece 10A, the second outer block piece 9B, and the second inner block piece 10B can be further suppressed. The inner top surface 28 of the inner portion 27 in this embodiment descends toward the second inner block piece 10B side. Also, the outer top surface 30 of the outer portion 29 descends toward the first outer block piece 9A side.

[0051] FIG. 11 is a plan view of the tread portion 2 of another embodiment. As shown in FIG. 11, in this embodiment, the tie bar 12 is provided in each of the first shoulder lateral grooves 15 and each of the second shoulder lateral grooves 16. The inner portion 27 of the tie bar 12 is provided, for example, in each of the second shoulder lateral grooves 16. The outer portion 29 is provided in each of the first shoulder lateral grooves 15. The arrangement of the tie bar 12 is not limited to that shown in the figure. For example, the inner portion 27 of the tie bar 12 may be provided in the first shoulder lateral groove 15, and the outer portion 29 may be provided in the second shoulder lateral groove 16. Moreover, the inner portion 27 and the outer portion 29 may be provided only in the first shoulder lateral groove 15, or the inner portion 27 and the outer portion 29 may be provided in the first shoulder lateral groove 15 and the second shoulder lateral groove 16 (not shown).

[0052] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above specific embodiment and can be modified and implemented in various aspects.

[0053] [Note] The present invention includes the following aspects.

[0054] [Invention 1] A tire having a tread portion, The tread portion includes a shoulder block row, The shoulder block row includes a plurality of shoulder lateral grooves and a plurality of shoulder blocks arranged alternately in the tire circumferential direction, Each of the shoulder blocks is divided into an axially outer block piece and an axially inner block piece by a dividing groove extending in a tire circumferential direction, At least one of the shoulder lateral grooves is provided with a tie bar that locally raises a groove bottom, The tie bar connects at least three of the four block pieces facing the at least one shoulder lateral groove. tire. [Invention 2] 2. The tire according to claim 1, wherein the groove depth of the dividing groove is smaller than the groove depth of the shoulder lateral groove. [Invention 3] The tire according to the first or second aspect of the present invention, wherein the tie bar connects four block pieces facing the at least one shoulder lateral groove. [Invention 4] The tire according to Invention 3, wherein the tie bar includes an inner portion connecting the two inner block pieces and one outer block piece facing the at least one shoulder lateral groove. [Invention 5] The inner portion has an inner top surface facing radially outward in the tire direction, The tire according to invention 4, wherein the inner top surface descends in the first tire circumferential direction. [Invention 6] The tire according to the fourth or fifth aspect of the present invention, wherein the tie bar includes an outer portion connecting the two outer block pieces and one inner block piece facing the at least one shoulder lateral groove. [Invention 7] The outer portion has an outer top surface facing radially outward in the tire direction, The tire according to claim 6, wherein the outer top surface descends toward the second tire circumferential direction. [Invention 8] The tire according to invention 6 or 7, wherein, in the tread area of ​​each of the plurality of shoulder blocks, the sum of the area of ​​the two outer block pieces and the one inner block piece connected by the outer portion is 80% to 120% of the sum of the area of ​​the two inner block pieces and the one outer block piece connected by the inner portion. [The present invention 9] 9. The tire according to any one of claims 6 to 8, wherein the maximum raised height of the outer portion is greater than the maximum raised height of the inner portion. [The present invention 10] 10. The tire according to any one of claims 6 to 9, wherein the tie bar integrally comprises the inner portion and the outer portion. [The present invention 11] 11. The tire according to any one of claims 1 to 10, wherein the maximum raised height of the tie bar is 10% or more of the maximum block height of the shoulder block. [The present invention 12] The tie bar has a top surface facing outward in the tire radial direction, The top surface includes an inner end and an outer end in the tire axial direction, 12. The tire according to any one of claims 1 to 11, wherein each of the inner end and the outer end is inclined at an angle of 10 to 60° with respect to the tire circumferential direction. [The present invention 13] The dividing groove is inclined with respect to the tire circumferential direction, 12. The tire according to any one of claims 1 to 11, wherein the dividing groove forms an angle of 10 to 80° with respect to the tire circumferential direction. [Explanation of symbols]

[0055] 1 Tire 4. Shoulder Block Row 6 Shoulder groove 6s groove bottom 7. Shoulder Block 8 dividing groove 9 Outer block piece 10 Inner block piece 12 Tie bar

Claims

1. A tire having a tread portion, The tread portion includes a shoulder block row, The shoulder block row includes a plurality of shoulder lateral grooves and a plurality of shoulder blocks arranged alternately in the tire circumferential direction, Each of the shoulder blocks is divided into an axially outer block piece and an axially inner block piece by a dividing groove extending in a tire circumferential direction, At least one of the shoulder lateral grooves is provided with a tie bar that locally raises a groove bottom, The tie bar connects at least three of the four block pieces facing the at least one shoulder lateral groove. tire.

2. The tire according to claim 1 , wherein a groove depth of the dividing groove is smaller than a groove depth of the shoulder lateral groove.

3. The tire according to claim 1 or 2, wherein the tie bar connects four block pieces facing the at least one shoulder lateral groove.

4. The tire according to claim 3 , wherein the tie bar includes an inner portion connecting two of the inner block pieces facing the at least one shoulder lateral groove and one of the outer block pieces.

5. The inner portion has an inner top surface facing radially outward in the tire direction, The tire of claim 4 , wherein the inner apex surface slopes downward in a first tire circumferential direction.

6. The tire according to claim 4 , wherein the tie bar includes an outer portion connecting two of the outer block pieces and one of the inner block pieces facing the at least one shoulder lateral groove.

7. The outer portion has an outer top surface facing radially outward in the tire direction, The tire of claim 6 , wherein the outer apex surface slopes downwardly in a second circumferential direction.

8. 7. The tire according to claim 6, wherein in a tread area of ​​each of the plurality of shoulder blocks, a sum of an area of ​​the two outer block pieces and an area of ​​the one inner block piece connected by the outer portion is 80% to 120% of a sum of an area of ​​the two inner block pieces and an area of ​​the one outer block piece connected by the inner portion.

9. 7. The tire of claim 6, wherein the maximum rise height of said outer portion is greater than the maximum rise height of said inner portion.

10. The tire of claim 6 , wherein said tie bar comprises said inboard portion and said outboard portion integrally.

11. The tire according to claim 1 or 2, wherein a maximum raised height of the tie bar is 10% or more of a maximum block height of the shoulder block.

12. The tie bar has a top surface facing outward in the tire radial direction, The top surface includes an inner end and an outer end in the tire axial direction, 3. The tire according to claim 1, wherein each of the inner end and the outer end is inclined at an angle of 10 to 60 degrees with respect to the tire circumferential direction.

13. The dividing groove is inclined with respect to the tire circumferential direction, 3. The tire according to claim 1, wherein an angle of the dividing groove with respect to the tire circumferential direction is 10 to 80 degrees.

Images