tire

Abstract

To provide a tire which is excellent in steering stability.SOLUTION: A tire has a tread part 2. The tread part 2 includes a first shoulder land part 11. The first shoulder land part 11 is provided with multiple first shoulder lateral grooves 20. At least one of the first shoulder lateral grooves 20 includes a first groove wall 21 and a second groove wall 22 and a tie bar 24. The tie bar 24 includes an outer side surface 25 which continues into the first groove wall 21 and the second groove wall 22. The outer side surface 25 includes: a first edge 26 which continues into the first groove wall 21; and a second edge 27 which continues into the second groove wall 22. A length of the second edge 27 is smaller than a length of the first edge 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to tires. [Background technology]

[0002] For example, Patent Document 1 below proposes a tire in which tie bars with raised groove bottoms are provided in the first shoulder lateral grooves. The tie bars increase the rigidity of the first shoulder land portion of the tire, and are expected to improve driving performance on dry roads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-039407 Summary of the Invention [Problem to be solved by the invention]

[0004] BACKGROUND ART In recent years, with the advancement of vehicle performance, there has been a demand for further improvement in the steering stability on dry road surfaces (hereinafter sometimes simply referred to as "steering stability") of tires.

[0005] The present disclosure has been devised in view of the above circumstances, and has as its main object to provide a tire with excellent steering stability. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a tread portion, the tread portion including a first tread edge, a first shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a first shoulder land portion including the first tread edge and divided into the first shoulder circumferential groove, the first shoulder land portion being provided with a plurality of first shoulder lateral grooves extending from the first shoulder circumferential groove at least to the first tread edge, at least one of the first shoulder lateral grooves including first and second groove walls facing each other and extending in the tire radial direction, and a tie bar having a locally raised groove bottom, the tie bar extending along the tread surface of the first shoulder land portion and including an outer side surface connected to the first groove wall and the second groove wall, the outer side surface including a first edge connected to the first groove wall and a second edge connected to the second groove wall, the length of the second edge being shorter than the length of the first edge. [Effects of the Invention]

[0007] By adopting the above-described configuration, the tire of the present disclosure can improve steering stability. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a development view of a tread portion of a tire according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of a first shoulder land portion and a first middle land portion of FIG. [Figure 3] FIG. 3 is an enlarged perspective view of a first shoulder lateral groove of FIG. 2. [Figure 4] FIG. 3 is an end view taken along line AA in FIG. 2. [Figure 5] FIG. 3 is a cross-sectional view taken along line BB in FIG. 2. [Figure 6] FIG. 2 is an enlarged plan view of the outer surface of the tie bar. [Figure 7] FIG. 3 is a cross-sectional view taken along line CC in FIG. 2. [Figure 8] 2 is an enlarged view of a second shoulder land portion, a second middle land portion, and a crown land portion of FIG. 1. FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along the line DD in FIG. 8. [Figure 10] FIG. 9 is a cross-sectional view taken along the line EE in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described below with reference to the drawings. Fig. 1 is a development view of a tread portion 2 of a tire 1 showing an embodiment of the present disclosure. The tire 1 of this embodiment is suitably used, for example, as a pneumatic tire for passenger cars. However, the present disclosure is not limited to such an embodiment and may also be applied to pneumatic tires for heavy loads and non-pneumatic tires that are not filled with pressurized air inside the tire.

[0010] As shown in Fig. 1 , the tread portion 2 of the tire 1 includes a plurality of circumferential grooves 3 extending continuously in the tire circumferential direction between a first tread edge T1 and a second tread edge T2, and a plurality of land portions 4 separated by these circumferential grooves 3. The tire 1 of this embodiment is a so-called five-rib tire in which the tread portion 2 is configured with four circumferential grooves 3 and five land portions 4. However, the present disclosure is not limited to this aspect. In another embodiment of the tire 1 of the present disclosure, for example, the tread portion 2 may be a so-called four-rib tire in which the tread portion 2 is configured with three circumferential grooves 3 and four land portions 4.

[0011] The tread portion 2 of this embodiment has a specified orientation for installation on a vehicle. In this embodiment, the first tread edge T1 is intended to be located on the outer side of the vehicle when installed on the vehicle, and the second tread edge T2 is intended to be located on the inner side of the vehicle when installed on the vehicle. However, the present disclosure is not limited to this aspect.

[0012] The first tread edge T1 and the second tread edge T2 each correspond to the edge of the contact patch when 70% of the normal load is applied to the tire 1 in its normal state and the tread portion 2 is brought into contact with a flat surface at a camber angle of 0°.

[0013] "Normal condition" means, in the case of a pneumatic tire for which various standards are established, that the tire is mounted on a normal rim, inflated to the normal internal pressure, and is in an unloaded state. In the case of a tire for which various standards are not established or a non-pneumatic tire, the normal condition means a standard use state according to the intended use of the tire, in which the tire is not mounted on a vehicle and is unloaded. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal condition.

[0014] A "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, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "design rim," and in the case of ETRTO, it is called a "measuring rim."

[0015] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0016] For pneumatic tires for which various standards are established, "normal load" refers to the load specified for each tire in the standard system including the standard on which the tire is based. For JATMA, this is "maximum load capacity," for TRA, this is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, this is "LOAD CAPACITY." For tires for which various standards are not established, "normal load" refers to the maximum load that can be applied when using the tire in accordance with the above standards.

[0017] The circumferential grooves 3 include a first shoulder circumferential groove 5. The first shoulder circumferential groove 5 is adjacent to the first tread edge T1. The circumferential grooves 3 of this embodiment also include a second shoulder circumferential groove 6, a first crown circumferential groove 7, and a second crown circumferential groove 8. The second shoulder circumferential groove 6 is adjacent to the second tread edge T2. The first crown circumferential groove 7 is provided between the first shoulder circumferential groove 5 and the tire equator C. The second crown circumferential groove 8 is provided between the second shoulder circumferential groove 6 and the tire equator C.

[0018] The axial distance L1 from the tire equator C to the groove center line of the first shoulder circumferential groove 5 or the second shoulder circumferential groove 6 is preferably, for example, 25% to 35% of the tread width TW. The axial distance L2 from the tire equator C to the groove center line of the first crown circumferential groove 7 or the second crown circumferential groove 8 is preferably, for example, 5% to 20% of the tread width TW. The tread width TW is the axial distance from the first tread edge T1 to the second tread edge T2 in the normal state.

[0019] Each circumferential groove 3 of this embodiment extends, for example, linearly in parallel to the tire circumferential direction. Each circumferential groove 3 may extend, for example, in a wavy shape.

[0020] The groove width Wa of each circumferential groove 3 is preferably at least 3 mm or more. Furthermore, the groove width Wa of each circumferential groove 3 is preferably 3.0% to 5.0% of the tread width TW. As a more preferable aspect in this embodiment, among the multiple circumferential grooves 3, the first shoulder circumferential groove 5 has the smallest groove width. However, the present disclosure is not limited to this aspect.

[0021] The land portion 4 includes a first shoulder land portion 11. The first shoulder land portion 11 includes the first tread edge T1 and is located axially outward of the first shoulder circumferential groove 5. The land portion 4 of this embodiment also includes a second shoulder land portion 12, a first middle land portion 13, a second middle land portion 14, and a crown land portion 15. The second shoulder land portion 12 includes the second tread edge T2 and is located axially outward of the second shoulder circumferential groove 6. The first middle land portion 13 is located between the first shoulder circumferential groove 5 and the first crown circumferential groove 7. The second middle land portion 14 is located between the second shoulder circumferential groove 6 and the second crown circumferential groove 8. The crown land portion 15 is located between the first crown circumferential groove 7 and the second crown circumferential groove 8.

[0022] Fig. 2 shows an enlarged view of the first shoulder land portion 11 and the first middle land portion 13. As shown in Fig. 2, the first shoulder land portion 11 is provided with a plurality of first shoulder lateral grooves 20 extending from the first shoulder circumferential groove 5 to at least the first tread edge T1. In this embodiment, the first shoulder lateral grooves 20 extend to a position beyond the first tread edge T1.

[0023] Fig. 3 shows an enlarged perspective view of the first shoulder lateral groove 20. Fig. 4 shows an end view taken along line AA in Fig. 2. As shown in Figs. 3 and 4, at least one of the first shoulder lateral grooves 20 includes a first groove wall 21 and a second groove wall 22 that face each other and extend in the tire radial direction, and a tie bar 24 whose groove bottom is locally raised. In this embodiment, the first groove wall 21 is configured on one side of the first shoulder lateral groove 20 in the tire circumferential direction (the upper side in Fig. 2, hereinafter sometimes referred to as the "first side in the tire circumferential direction"). The second groove wall 22 is configured on the other side of the first shoulder lateral groove 20 in the tire circumferential direction (the lower side in Fig. 2, hereinafter sometimes referred to as the "second side in the tire circumferential direction").

[0024] Fig. 5 shows a cross-sectional view taken along line BB in Fig. 2. As shown in Fig. 5, the tie bar 24 extends along the tread surface of the first shoulder land portion 11 and includes an outer surface 25 that is continuous with the first groove wall 21 and the second groove wall 22. Fig. 6 shows an enlarged plan view of the outer surface 25. As shown in Fig. 6, the outer surface 25 includes a first edge 26 that is continuous with the first groove wall 21 and a second edge 27 that is continuous with the second groove wall 22. The first edge 26 and the second edge 27 correspond to the boundary between the outer surface 25 and the first groove wall 21 or the second groove wall 22. When the outer surface 25 and the first groove wall 21 or the second groove wall 22 are continuous to form a curved surface, the boundary corresponds to the midpoint of the curve that forms the curved surface in the cross section of the first shoulder lateral groove 20.

[0025] The length L4 of the second edge is smaller than the length L3 of the first edge 26. By adopting the above-described configuration, the tire 1 of the present disclosure can improve steering stability. The following mechanism is presumed to be the reason for this.

[0026] In the present disclosure, the tie bars 24 are provided in the first shoulder lateral grooves 20, thereby improving the rigidity of the first shoulder land portion 11 and improving the steering stability can be expected.

[0027] As a result of extensive research, the developers discovered that while conventional tie bars can be expected to improve the rigidity of the land area, they also found that minute distortions occurred on the contact surface of the land area around the tie bars, resulting in uneven ground pressure acting in the surrounding area.

[0028] To achieve uniform ground contact pressure, the present disclosure sets the length L4 of the second edge 27 of the outer surface 25 of the tie bar 24 to be shorter than the length L3 of the first edge 26. This allows for appropriate deformation on the side of the second groove wall 22 where the second edge 27 is connected, thereby uniforming the ground contact pressure acting on the periphery. This provides a strong grip force in the periphery, further improving handling stability. This effect cannot be achieved by simply adjusting the length of a conventional tie bar; it can be achieved by positioning the second edge 27, which promotes appropriate deformation, opposite the first edge 26, which has a high rigidity-improving effect. In other words, the tire 1 of the present disclosure can achieve significantly improved handling stability compared to tires equipped with conventional tie bars.

[0029] The following describes the configuration of this embodiment in more detail. Note that each configuration described below represents a specific aspect of this embodiment. Therefore, it goes without saying that the present disclosure can achieve the above-described effects even if it does not include the configurations described below. Furthermore, even if any one of the configurations described below is applied alone to a tire of the present disclosure having the above-described characteristics, performance improvement corresponding to each configuration can be expected. Furthermore, when several of the configurations described below are applied in combination, combined performance improvement corresponding to each configuration can be expected.

[0030] 2, the multiple first shoulder lateral grooves 20 have substantially the same configuration. Furthermore, the first shoulder lateral grooves 20 are slightly inclined with respect to the tire axial direction, for example. The angle of the first shoulder lateral grooves 20 with respect to the tire axial direction is, for example, 15° or less.

[0031] As shown in Fig. 4, the maximum depth d1 of the first shoulder lateral grooves 20 is 80% to 100% of the maximum depth of the first shoulder circumferential groove 5 (shown in Fig. 2). Such first shoulder lateral grooves 20 can exhibit a good balance between steering stability and wet performance.

[0032] 2 and 3, the tie bar 24 is preferably disposed, for example, axially inward of the axial center of the contact patch of the first shoulder land portion 11 (the surface between the first tread edge T1 and the first shoulder circumferential groove 5). In a more preferable embodiment, the tie bar 24 of this embodiment is provided at the end of the first shoulder lateral groove 20 on the first shoulder circumferential groove 5 side. Such a tie bar 24 helps to improve steering stability.

[0033] As shown in Fig. 5, the depth d2 from the tread surface of the first shoulder land portion 11 to the outer surface 25 of the tie bar 24 is preferably 20% to 40% of the maximum depth d1 (shown in Fig. 4) of the first shoulder lateral groove 20. This improves steering stability and wet performance in a well-balanced manner.

[0034] As shown in Fig. 6, the outer surface 25 is preferably trapezoidal in plan view of the tread. That is, the outer surface 25 is a quadrangle surrounded by a first edge 26 and a second edge 27 that extend parallel to each other and a third edge 28 and a fourth edge 29 that extend non-parallel to each other. The third edge 28 is disposed on the side of the first tread edge T1 (shown in Fig. 2), and the fourth edge 29 is disposed on the side of the first shoulder circumferential groove 5 (shown in Fig. 2). However, the outer surface 25 of the present disclosure is not limited to this form.

[0035] The length L3 of the first edge 26 and the length L4 of the second edge 27 are each 10% to 50% of the axial width W5 (shown in FIG. 2) of the contact patch of the first shoulder land portion 11. The length L4 of the second edge 27 is preferably 20% or more, more preferably 30% or more, and preferably 60% or less, more preferably 50% or less of the length L3 of the first edge 26. Furthermore, by defining the relationship between the lengths L3 and L4 in this manner, the third edge 28 is inclined, for example, at an angle of 10 to 30° with respect to the tire axial direction. The fourth edge 29 extends along the tire circumferential direction. The outer side surface 25, with each edge defined in this manner, improves the rigidity of the first shoulder land portion 11 and uniforms the contact pressure, further improving handling stability.

[0036] The area of ​​the outer surface 25 is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 30% or less of the opening area of ​​the first shoulder lateral groove 20 (shown in FIG. 2) between the first tread edge T1 and the first shoulder circumferential groove 5. This improves the steering stability and wet performance in a well-balanced manner.

[0037] 2 and 4, the first shoulder lateral groove 20 preferably includes a chamfered portion 30. The chamfered portion 30 is configured to include an inclined surface between the tread surface of the first shoulder land portion 11 and the groove wall. Such a chamfered portion 30 helps to further improve the uniformity of ground contact pressure.

[0038] The developers found that the above-mentioned effects can be further improved by specifying the size of the inclined surface of the chamfered portion 30 according to the lengths of the first edge 26 and the second edge 27 of the outer surface 25. Based on this finding, the chamfered portion 30 of this embodiment includes a first inclined surface 31 extending from the tread surface of the first shoulder land portion 11 to the first groove wall 21 and a second inclined surface 32 extending from the tread surface to the second groove wall 22, and the maximum width W2 of the second inclined surface 32 is larger than the maximum width W1 of the first inclined surface 31 in a tread plan view. This allows the second inclined surface 32 to have a larger width on the side of the second groove wall 22, which is more susceptible to deformation. Therefore, the second inclined surface 32 can come into contact with the ground as the second groove wall 22 deforms, further improving handling stability.

[0039] The width W1 of the first inclined surface 31 is, for example, 1.0 to 1.5 mm. The width W2 of the second inclined surface 32 is, for example, 2.5 to 3.5 mm. If the second inclined surface 32 is small, it becomes difficult to obtain the above-mentioned effect, and if the second inclined surface 32 is large, the tread area of ​​the first shoulder land portion 11 becomes small, which may impair steering stability. From this perspective, the width W2 of the second inclined surface 32 is preferably 1.5 times or more, more preferably 2.0 times or more, and preferably 3.5 times or less, and more preferably 3.0 times or less, of the width W1 of the first inclined surface 31.

[0040] The inclination angle θ1 of the first inclined surface 31 with respect to the tire normal line is, for example, 35 to 55°. The inclination angle θ2 of the second inclined surface 32 with respect to the tire normal line is larger than the inclination angle θ1 and is, for example, 60 to 75°. However, the present disclosure is not limited to such an embodiment.

[0041] As shown in Figure 5, the first shoulder lateral grooves 20 are provided with groove bottom sipes 35 that open on the outer side surface 25. The depth d3 from the tread surface of the first shoulder land portion 11 to the bottom of the groove bottom sipe 35 is, for example, 50% to 80% of the maximum depth d1 (shown in Figure 4) of the first shoulder lateral grooves 20. Such groove bottom sipes 35 help to maintain the drainage performance of the first shoulder lateral grooves 20. In this specification, the term "sipe" refers to a cut having a width of approximately 0.5 to 1.5 mm.

[0042] 2, the first middle land portion 13 is provided with a plurality of first middle shallow grooves 40. The first middle shallow grooves 40 extend, for example, from the first shoulder circumferential groove 5 and terminate within the first middle land portion 13. Such first middle shallow grooves 40 help maintain the rigidity of the first middle land portion 13 and improve steering stability.

[0043] The first middle shallow groove 40 preferably communicates with the first shoulder circumferential groove 5 at a position close to the first shoulder lateral groove 20. Specifically, it is preferable that the region obtained by extending the end of the first shoulder circumferential groove 5 side of the first shoulder circumferential groove 5 parallel to the tire axial direction overlaps with the groove width of the end of the first middle shallow groove 40 side of the first shoulder circumferential groove 5 by 50% or more. Such an arrangement of the first shoulder lateral grooves 20 and the first middle shallow grooves 40 helps to improve wet performance.

[0044] Fig. 7 shows a cross section taken along line CC in Fig. 2. As shown in Fig. 7, the first middle shallow groove 40 of this embodiment includes a main body portion 41 and a middle groove bottom sipe 42 extending radially from the bottom of the main body portion 41. The depth d4 of the main body portion 41 is smaller than the depth d2 (shown in Fig. 5) from the tread surface of the first shoulder land portion 11 to the outer surface 25 of the tie bar 24, and is, for example, 80% to 95% of the depth d2. The total depth d5 ​​of the first middle shallow groove 40 is, for example, 70% to 90% of the maximum depth d1 (shown in Fig. 4) of the first shoulder lateral groove 20. Such a first middle shallow groove 40 helps to improve driving stability and wet performance in a well-balanced manner.

[0045] The main body portion 41 of the first middle shallow groove 40 includes, for example, a first shallow groove wall 43 and a second shallow groove wall 44 having different widths in a tread plan view. In a tread plan view, a width W4 of the second shallow groove wall 44 is larger than a width W3 of the first shallow groove wall 43. Specifically, the width W4 of the second shallow groove wall 44 is 1.3 to 2.0 times the width W3 of the first shallow groove wall 43.

[0046] In a preferred embodiment, as shown in Fig. 2, the first shallow groove wall 43 is disposed on a first side in the tire circumferential direction, and the second shallow groove wall 44 is disposed on a second side in the tire circumferential direction. This allows wear to progress uniformly in the first shoulder land portion 11 and the first middle land portion 13, improving uneven wear resistance.

[0047] The first middle land portion 13 is preferably provided with connecting sipes 45 extending from the first middle shallow grooves 40 to the first crown circumferential grooves 7. In this embodiment, first middle shallow grooves 40 with connecting sipes 45 and first middle shallow grooves 40 with no connecting sipes 45 are provided alternately in the tire circumferential direction. Such connecting sipes 45 can provide frictional force during wet driving while maintaining the rigidity of the first middle land portion 13.

[0048] 8 shows an enlarged view of the second shoulder land portion 12, the second middle land portion 14, and the crown land portion 15. As shown in FIG. 8, the second shoulder land portion 12 is provided with a plurality of second shoulder lateral grooves 50. For example, the second shoulder lateral grooves 50 extend axially inward from at least the second tread edge T2 and terminate without communicating with the second shoulder circumferential groove 6. Such second shoulder lateral grooves 50 are useful for improving steering stability and wet performance in a well-balanced manner.

[0049] Figure 9 shows a cross section taken along line DD in Figure 8. As shown in Figure 9, the second shoulder lateral groove 50 includes a chamfered portion 51. The chamfered portion 51 includes a third inclined surface 53 and a fourth inclined surface 54. In a plan view of the tread, the width of the third inclined surface 53 is greater than the width of the fourth inclined surface 54. The third inclined surface 53 can have the same configuration as the second inclined surface 32 (shown in Figure 4) of the first shoulder lateral groove 20 described above. The fourth inclined surface 54 can have the same configuration as the first inclined surface 31 (shown in Figure 4) of the first shoulder lateral groove 20 described above.

[0050] 8, the third inclined surface 53 is provided on the first circumferential side of the tire, and the fourth inclined surface 54 is provided on the second circumferential side of the tire. In other words, the size relationship of the inclined surfaces of the chamfered portions is opposite between the first shoulder lateral grooves 20 and the second shoulder lateral grooves 50. This improves traction performance and braking performance on dry roads in a balanced manner.

[0051] The second middle land portion 14 is provided with a plurality of outer second middle shallow grooves 56 and a plurality of inner second middle shallow grooves 57. The outer second middle shallow grooves 56 extend from the second crown circumferential groove 8 and terminate within the second middle land portion 14. The inner second middle shallow groove 57 extends from the second shoulder circumferential groove 6 and terminates within the second middle land portion 14. The outer second middle shallow grooves 56 and the inner second middle shallow groove 57 terminate within the second middle land portion 14 without crossing the axial center position of the second middle land portion 14. Such outer second middle shallow grooves 56 and inner second middle shallow grooves 57 help to improve steering stability and wet performance in a balanced manner.

[0052] The outer second middle shallow groove 56 and the inner second middle shallow groove 57 each have substantially the same cross-sectional shape as the above-described first middle shallow groove 40. Therefore, the outer second middle shallow groove 56 and the inner second middle shallow groove 57 can have the same cross-sectional shape as the first middle shallow groove 40 shown in FIG.

[0053] The outer second middle shallow groove 56 has a second shallow groove wall 56a that is wider and disposed on the second circumferential side. The inner second middle shallow groove 57 has a second shallow groove wall 57a that is wider and disposed on the first circumferential side. This suppresses uneven wear of the second middle land portion 14 and improves traction and braking performance on dry roads in a balanced manner.

[0054] The crown land portion 15 is provided with a plurality of crown shallow grooves 60. The crown shallow grooves 60 extend, for example, from the first crown circumferential groove 7 and terminate within the crown land portion 15. The length L5 of the crown shallow grooves 60 in the tire axial direction is, for example, 40% to 60% of the width W6 of the crown land portion 15 in the tire axial direction.

[0055] Fig. 10 shows a cross section taken along line EE in Fig. 8. As shown in Fig. 10, no groove bottom sipes are provided in the crown shallow groove 60. Such crown shallow groove 60 helps to maintain the rigidity of the crown land portion 15 and to exhibit excellent driving stability.

[0056] Although a tire according to one embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the above-described specific embodiment and can be modified and implemented in various aspects. [Example]

[0057] Pneumatic tires of size 235 / 35R19 having the basic pattern of FIG. 1 were prototyped based on the specifications in Tables 1 and 2. Furthermore, tires were prototyped as Comparative Examples 1 to 3, in which the first and second edges of the outer surfaces of the tie bars provided in the first shoulder lateral grooves were the same length. Except for the above-mentioned features, the tires of Comparative Examples 1 to 3 were essentially the same as the tires of the Examples. Furthermore, these test tires were tested for steering stability and wet performance. The common specifications and test methods for each test tire are as follows: Rim: 17x8.0 Tire pressure: 260kPa on all wheels Test vehicle: 2000cc, front-wheel drive Tire mounting position: All wheels

[0058] <Handling stability> The test vehicle was driven on a test course consisting of a dry road surface, and the handling stability was evaluated by the driver's senses. The results are expressed as a score, with the handling stability of Comparative Example 1 being 100, and a higher score indicates better handling stability.

[0059] <Wet performance> The wet performance of the test vehicle was evaluated by the driver's senses when the test vehicle was driven on a test course consisting of a wet road surface. The results are expressed as a score, with the wet performance of Comparative Example 1 being 100, and a higher score indicates better wet performance. The test results are shown in Tables 1-2.

[0060] [Table 1]

[0061] [Table 2]

[0062] As a result of the test, it was confirmed that the tires of the examples had significantly improved steering stability. It was also confirmed that the tires of the examples had improved wet performance due to improved grip performance resulting from uniform contact pressure.

[0063] [Note] The present disclosure includes the following aspects.

[0064] [Disclosure 1] A tire having a tread portion, the tread portion includes a first tread edge, a first shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a first shoulder land portion including the first tread edge and divided by the first shoulder circumferential groove, The first shoulder land portion is provided with a plurality of first shoulder lateral grooves extending from the first shoulder circumferential groove to at least the first tread edge, At least one of the first shoulder lateral grooves includes a first groove wall and a second groove wall that face each other and extend in the tire radial direction, and a tie bar whose groove bottom is locally raised, the tie bar extends along the tread surface of the first shoulder land portion and includes an outer surface continuous with the first groove wall and the second groove wall, the outer surface includes a first edge connected to the first groove wall and a second edge connected to the second groove wall, The length of the second edge is smaller than the length of the first edge. tire. [Disclosure 2] the first shoulder lateral groove includes a chamfered portion, the chamfered portion includes a first inclined surface extending from the tread surface to the first groove wall and a second inclined surface extending from the tread surface to the second groove wall; The tire according to Disclosure 1, wherein, in a plan view of the tread, the maximum width of the second inclined surface is larger than the maximum width of the first inclined surface. [Disclosure 3] The tire according to Disclosure 2, wherein the width of the second inclined surface is 2.0 to 3.0 times the width of the first inclined surface. [Disclosure 4] The tire according to Disclosure 2 or 3, wherein an inclination angle of the second inclined surface with respect to the tire normal is larger than an inclination angle of the first inclined surface with respect to the tire normal. [Disclosure 5] The tire according to any one of Present Disclosures 1 to 4, wherein the tie bar is provided at an end of the first shoulder lateral groove on the side of the first shoulder circumferential groove. [Disclosure 6] The tire according to any one of Disclosures 1 to 5, wherein the outer surface is trapezoidal in plan view of the tread. [Disclosure 7] The tire according to any one of disclosures 1 to 6, wherein the length of the second edge is 30% to 50% of the length of the first edge. [Disclosure 8] The tire according to any one of disclosures 1 to 7, wherein the area of ​​the outer side surface is 20% to 30% of the opening area of ​​the first shoulder lateral groove between the first tread edge and the first shoulder circumferential groove. [Disclosure 9] The tire according to any one of the first to eighth disclosures, wherein the first shoulder lateral groove is provided with a groove bottom sipe that opens on the outer surface. [Explanation of symbols]

[0065] 2 Tread section 5 First shoulder circumferential groove 11 First Shoulder Land Section 20 First shoulder groove 21 First trench wall 22 Second groove wall 24 Tie Bar 25 External surface 26 First Edge 27 Second Edge T1 First tread edge

Claims

1. A tire having a tread portion, the tread portion includes a first tread edge, a first shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a first shoulder land portion including the first tread edge and divided by the first shoulder circumferential groove, a plurality of first shoulder lateral grooves extending from the first shoulder circumferential groove to at least the first tread edge are provided in the first shoulder land portion, At least one of the first shoulder lateral grooves includes a first groove wall and a second groove wall that face each other and extend in the tire radial direction, and a tie bar whose groove bottom is locally raised, the tie bar extends along the tread surface of the first shoulder land portion and includes an outer surface that is continuous with the first groove wall and the second groove wall, the outer surface includes a first edge connected to the first groove wall and a second edge connected to the second groove wall, The length of the second edge is smaller than the length of the first edge, The length of the second edge is 30% to 50% of the length of the first edge. tire.

2. the first shoulder lateral groove includes a chamfered portion, the chamfered portion includes a first inclined surface extending from the tread surface to the first groove wall and a second inclined surface extending from the tread surface to the second groove wall; The tire according to claim 1 , wherein, in a plan view of the tread, a maximum width of the second inclined surface is larger than a maximum width of the first inclined surface.

3. 3. The tire according to claim 2, wherein the width of the second inclined surface is 2.0 to 3.0 times the width of the first inclined surface.

4. The tire according to claim 2 or 3, wherein an inclination angle of the second inclined surface with respect to a tire normal is larger than an inclination angle of the first inclined surface with respect to the tire normal.

5. The tire according to claim 1 , wherein the tie bar is provided at an end of the first shoulder lateral groove on the side of the first shoulder circumferential groove.

6. The tire according to claim 1 , wherein the outer surface is trapezoidal in a plan view of the tread.

7. The outer surface includes a third edge and a fourth edge extending non-parallel to each other, The length of the second edge is smaller than the length of the first edge, 7. The tire according to claim 1, wherein the third edge is disposed on the first tread edge side and is inclined at an angle of 10 to 30 degrees with respect to the tire axial direction.

8. The tire according to any one of claims 1 to 7, wherein an area of ​​the outer side surface is 20% to 30% of an opening area of ​​the first shoulder lateral groove between the first tread edge and the first shoulder circumferential groove.

9. The tire according to claim 1 , wherein the first shoulder lateral groove is provided with a groove bottom sipe that opens on the outer side surface.

Images