tire

Abstract

To provide a tire that can exert excellent ride comfort performance while maintaining abrasion resistance properties of a block.SOLUTION: A tire comprises a tread part 2. The tread part 2 includes a first tread end T1, shoulder circumferential grooves 5 and shoulder land parts 7. The shoulder land parts 7 are provided with a plurality of shoulder lateral grooves 12. The shoulder land parts 7 include a plurality of shoulder blocks 10 sectioned into the plurality of shoulder lateral grooves 12. Each of the plurality of shoulder blocks 10 is provided with at least one shoulder sipe 15. At least one of the shoulder lateral grooves 12 includes at least one tie-bar 20 whose groove bottom part is raised to connect the adjacent two shoulder blocks 10 to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 below proposes a pneumatic tire in which shoulder blocks are provided with shoulder longitudinal sub-grooves extending in the tire circumferential direction, The shoulder longitudinal sub-grooves reduce the lateral rigidity of the shoulder blocks in the tire axial direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-137015 Summary of the Invention [Problem to be solved by the invention]

[0004] Reducing the rigidity of the tread blocks increases the amount of deformation of the blocks during driving, which increases the wear energy acting on the blocks and ultimately tends to reduce wear resistance.

[0005] The present disclosure has been devised in view of the above circumstances, and has as its main object to provide a tire that can exhibit excellent ride comfort while maintaining the wear resistance of the blocks. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a tread portion, wherein the tread portion includes a first tread edge, a shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a shoulder land portion including the first tread edge and divided into the shoulder circumferential groove, wherein the shoulder land portion is provided with a plurality of shoulder lateral grooves extending from the shoulder circumferential groove at least to the first tread edge, the shoulder land portion includes a plurality of shoulder blocks divided into the plurality of shoulder lateral grooves, each of the plurality of shoulder blocks is provided with at least one shoulder sipe that is connected to the shoulder lateral groove and terminates within the shoulder block, and at least one of the shoulder lateral grooves includes at least one tie bar with a raised groove bottom that connects two adjacent shoulder blocks. [Effects of the Invention]

[0007] By adopting the above-described configuration, the tire of the present disclosure can exhibit excellent ride comfort while maintaining the wear resistance of the blocks. [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 shoulder land portion and a middle land portion of FIG. [Figure 3] FIG. 3 is an enlarged view of the shoulder block and the shoulder lateral groove of FIG. 2. [Figure 4] FIG. 3 is a cross-sectional 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 view of the crown land portion of FIG. [Figure 7] FIG. 2 is a development view of a tread portion of a tire of a comparative example. 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 mounting orientation of the tread portion 2 on a vehicle is not specified, and the rotation direction is not specified either. For convenience, in each drawing in this specification, the first tread edge T1 is shown as the tread edge on the left side of the tire equator C, and the second tread edge T2 is shown as the tread edge on the right side of the tire equator C, but this is not limited to this. It is desirable that the tread portion 2 has substantially the same configuration in the region between the first tread edge T1 and the tire equator C and the region between the second tread edge T2 and the tire equator C. Furthermore, as a more desirable aspect, the tread portion 2 of this embodiment has a so-called point-symmetric pattern.

[0012] The first tread edge T1 and the second tread edge T2 each correspond to the edge of the contact patch when a normal load is applied to the tire 1 in a 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 two shoulder circumferential grooves 5 and two crown circumferential grooves 6. The shoulder circumferential groove 5 is adjacent to the first tread edge T1 or the second tread edge T2. The two crown circumferential grooves 6 are arranged between the two shoulder circumferential grooves 5 so as to sandwich the tire equator C.

[0018] The axial distance L1 from the tire equator C to the groove center line of the shoulder circumferential groove 5 is preferably, for example, 20% to 30% of the tread width TW. The axial distance L2 from the tire equator C to the groove center line of the crown circumferential groove 6 is preferably, for example, 5% to 15% 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] It is desirable that the groove width W1 of each circumferential groove 3 is at least 3 mm or more. It is also desirable that the groove width W1 of each circumferential groove 3 is 3.0% to 5.0% of the tread width TW.

[0021] The land portion 4 includes two shoulder land portions 7. The shoulder land portion 7 includes the first tread edge T1 or the second tread edge T2, and is located axially outward of the shoulder circumferential groove 5. The two shoulder land portions 7 have substantially the same configuration.

[0022] The plurality of land portions 4 in this embodiment include two middle land portions 8 and one crown land portion 9. The middle land portion 8 is adjacent to the shoulder land portion 7 via the shoulder circumferential groove 5. The middle land portion 8 is also divided between the shoulder circumferential groove 5 and the crown circumferential groove 6. The two middle land portions 8 have substantially the same configuration. The crown land portion 9 is divided between the two crown circumferential grooves 6 and is provided on the tire equator C.

[0023] Fig. 2 shows an enlarged view of the shoulder land portion 7 and the middle land portion 8 provided on the first tread edge T1 side of the tire equator C. As shown in Fig. 2, the shoulder land portion 7 is provided with a plurality of shoulder lateral grooves 12 extending from the shoulder circumferential groove 5 to at least the first tread edge T1. As a result, the shoulder land portion 7 includes a plurality of shoulder blocks 10 divided by the plurality of shoulder lateral grooves 12.

[0024] 3 shows an enlarged view of three shoulder lateral grooves 12 and two shoulder blocks 10. As shown in FIG. 3, each of the shoulder blocks 10 is provided with at least one shoulder sipe 15 that communicates with the shoulder lateral groove 12 and terminates within the shoulder block 10.

[0025] In this specification, the term "sipe" refers to a small cut between two inner walls that face each other and extend substantially parallel to each other, with the width between the two walls being 2.0 mm or less. Furthermore, "substantially parallel" refers to a configuration in which the angle between the two inner walls is 10° or less. The width W2 of the sipe is preferably 0.5 to 1.5 mm, more preferably 0.5 to 1.0 mm. The sipe of this embodiment has a constant width from the opening to the bottom. However, this is not limited to this configuration, and the opening of the sipe may be provided with a chamfered portion. Furthermore, the sipe may have a so-called flask bottom, with the width expanded at the bottom.

[0026] Figure 4 shows a cross-sectional view taken along line AA in Figure 2. As shown in Figure 4, at least one of the shoulder lateral grooves 12 includes at least one tie bar 20 with a raised groove bottom that connects two adjacent shoulder blocks 10. Note that in Figures 1 to 3, the outline of the tie bar 20, which can be observed when viewing the shoulder lateral groove 12 from above, is omitted.

[0027] By adopting the above-described configuration, the tire 1 of the present disclosure can exhibit excellent ride comfort while maintaining the wear resistance of the blocks. The following mechanism is presumed to be the reason for this.

[0028] The shoulder sipes 15 of the present disclosure extend from the shoulder lateral grooves 12 and terminate within the shoulder blocks 10, thereby reducing the axial rigidity of the shoulder blocks 10 while maintaining the circumferential rigidity of the tire. This allows for improved ride comfort while maintaining wear resistance. Meanwhile, providing tie bars 20 in the shoulder lateral grooves 12 adequately suppresses deformation of the shoulder land portion 7, further maintaining wear resistance. It is believed that this mechanism in the present disclosure allows for excellent ride comfort while maintaining the block's wear resistance.

[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] As shown in FIG. 2, the axial width W2 of each shoulder block 10 is, for example, 15% to 25% of the tread width TW (shown in FIG. 1, and the same applies hereinafter). The circumferential length L4 of each shoulder block 10 is smaller than the axial width W2 of the shoulder block 10. Specifically, the circumferential length L4 of each shoulder block 10 is 60% to 75% of the axial width W2 of each shoulder block 10. This allows the tread surface of each shoulder block 10 to be elongated in the axial direction, and more preferably, rectangular.

[0031] The shoulder lateral grooves 12 are arranged, for example, at an angle of 30° or less relative to the tire axial direction. The angle of the shoulder lateral grooves 12 relative to the tire axial direction is preferably 20° or less, and more preferably 10° or less. In a more preferable embodiment, the shoulder lateral grooves 12 of this embodiment extend parallel to the tire axial direction. This further suppresses wear of the shoulder blocks 10.

[0032] To maintain wear resistance, the shoulder lateral grooves 12 extend axially from the shoulder circumferential groove 5 to the first tread edge T1 with a constant groove width. The groove width W4 of the shoulder lateral grooves 12 is preferably smaller than the groove width W3 of the shoulder circumferential groove 5. Specifically, the groove width W4 of the shoulder lateral grooves 12 is 85% to 95% of the groove width W3 of the shoulder circumferential groove 5.

[0033] As shown in FIG. 3, the shoulder sipes 15 include a first shoulder sipe 16 and a second shoulder sipe 17. The first shoulder sipe 16 communicates with a shoulder lateral groove 12 located on one circumferential side of the shoulder block 10 (the lower side in FIG. 3). The second shoulder sipe 17 communicates with a shoulder lateral groove 12 located on the other circumferential side of the shoulder block 10 (the upper side in FIG. 3). As a more desirable aspect, in this embodiment, one first shoulder sipe 16 and one second shoulder sipe 17 are provided in each shoulder block 10. This further improves ride comfort.

[0034] The first shoulder sipes 16 and the second shoulder sipes 17 are preferably located axially inward of the axial center position 10a (shown by a dashed line in FIG. 3 ) of the shoulder block 10. In a more preferred embodiment, the entire edge of the first shoulder sipe 16 and the entire edge of the second shoulder sipe 17 are located axially inward of the center position 10a. This reduces the rigidity of the axially inner region of the shoulder block 10, further improving ride comfort.

[0035] On the other hand, if the first shoulder sipes 16 and second shoulder sipes 17 are too close to the shoulder circumferential grooves 5, this may result in uneven wear of the shoulder blocks 10. For this reason, it is desirable that the axial distance L3 from the connection between the shoulder lateral groove 12 and the first shoulder sipe 16 or second shoulder sipe 17 to the axially inner end of the shoulder lateral groove 12 be, for example, 30% to 45% of the axial width W2 of the shoulder block 10 (shown in FIG. 2, and the same applies hereinafter).

[0036] The connecting portion 17a between the shoulder lateral groove 12 and the second shoulder sipe 17 is preferably offset in the tire axial direction from the connecting portion 16a between the shoulder lateral groove 12 and the first shoulder sipe 16. The axial distance L9 between the connecting portions 16a and 17a is preferably 5% to 10% of the axial width W2 of the shoulder block 10. This further improves the wear resistance of the shoulder block 10.

[0037] From the same viewpoint, it is desirable that the first shoulder sipes 16 and the second shoulder sipes 17 are inclined in the same direction relative to the tire circumferential direction. In this embodiment, the first shoulder sipes 16 and the second shoulder sipes 17 are inclined at the same angle relative to the tire circumferential direction. In addition, it is desirable that the angle θ1 between the shoulder lateral grooves 12 and the shoulder sipes 15 is 50 to 80°.

[0038] As shown in FIG. 2, the first shoulder sipes 16 and the second shoulder sipes 17 provided in one shoulder block 10 are arranged on a single imaginary belt 19 (marked with dots in FIG. 2) that extends with a very small width in a plan view of the tread portion 2. The imaginary belt 19 is an imaginary region that extends with a constant width and inclined in the same direction as the first shoulder sipes 16 and the second shoulder sipes 17. In a preferred embodiment, the first shoulder sipes 16 and the second shoulder sipes 17 are arranged so that the imaginary belt 19 has a width of 10 mm or less. In a more preferred embodiment, the first shoulder sipes 16 and the second shoulder sipes 17 are arranged on substantially the same imaginary straight line in this embodiment. This can further improve ride comfort.

[0039] It is desirable that the shoulder sipes 15 terminate within the shoulder blocks 10 without crossing the circumferential center positions 10b (shown by dashed lines in FIG. 2) of the shoulder blocks 10. Specifically, it is desirable that the circumferential length L5 of the shoulder sipes 15 is 25% to 35% of the circumferential length L4 of the shoulder blocks 10. Such shoulder sipes 15 help to improve wear resistance and ride comfort in a balanced manner.

[0040] In this embodiment, no grooves or sipes are provided on the tread surface of the shoulder block 10 except for the first shoulder sipes 16 and the second shoulder sipes 17. This ensures that the above-mentioned effects are achieved.

[0041] As shown in FIG. 4, at least one shoulder lateral groove 12 includes multiple tie bars 20. In a preferred embodiment, each shoulder lateral groove 12 includes multiple tie bars 20. Furthermore, the shoulder sipe 15 communicates with the shoulder lateral groove 12 at the same position as one of the multiple tie bars 20. This further improves wear resistance. Note that the above-mentioned configuration means that, in a cross section along the length of the shoulder lateral groove 12, the shoulder sipe 15 is included within a region obtained by extending the outer surface of the tie bar 20 radially outward in the tire. Furthermore, the center position in the height direction of the tie bar 20 is the boundary between the outer surface of the tie bar 20 and other surfaces.

[0042] The tie bars 20 include, for example, an inner tie bar 21, an outer tie bar 22, and an intermediate tie bar 23. The inner tie bar 21 is provided axially inward of the axial center position of the shoulder lateral groove 12 within the tread contact patch. In a preferred embodiment, the inner tie bar 21 is provided at the axially inner end of the shoulder lateral groove 12. Such inner tie bar 21 helps to suppress uneven wear around the inner end of the shoulder lateral groove 12.

[0043] The outer tie bar 22 is provided axially outward of the axial center of the shoulder lateral groove 12 in the tread contact area. In a preferred embodiment, the outer tie bar 22 is provided at the axially outer end of the shoulder lateral groove 12 in the tread contact area. Specifically, in a cross section along the length of the shoulder lateral groove 12, the first tread edge T1 is included within a region obtained by extending the outer surface of the outer tie bar 22 radially outward. Such an outer tie bar 22 helps to suppress uneven wear near the first tread edge T1.

[0044] The intermediate tie bar 23 is provided between both axial ends of the shoulder lateral grooves 12, and in this embodiment, it is provided between the outer tie bar 22 and the inner tie bar 21. Such an intermediate tie bar 23 can effectively prevent the shoulder lateral grooves 12 from opening excessively, further improving wear resistance. In this embodiment, the shoulder sipes 15 communicate with the shoulder lateral grooves 12 at the same position as the intermediate tie bar 23.

[0045] In this embodiment, the shoulder lateral groove 12 includes an inner tie bar 21, an outer tie bar 22, and an intermediate tie bar 23, but the present disclosure is not limited to this embodiment, and only one of these tie bars 20 may be provided in the shoulder lateral groove 12, or two of these tie bars 20 may be selected and arranged.

[0046] The axial length L6 of one tie bar 20 is, for example, 15% to 25% of the axial width W2 of the shoulder block 10. The total axial length of the tie bars 20 arranged in one shoulder lateral groove 12 is preferably 40% to 60% of the width W2 of the shoulder block 10. This improves the balance between wear resistance and ride comfort. The axial length of the tie bar 20 is measured at the center position of the tie bar 20 in the height direction.

[0047] In this embodiment, the inner tie bar 21, the outer tie bar 22, and the intermediate tie bar 23 are configured to have the same height. The maximum height h1 of the tie bar 20 is preferably 25% to 40% of the maximum depth d1 of the shoulder lateral groove 12.

[0048] As shown in Fig. 2, the middle land portion 8 is provided with a plurality of middle lateral grooves 26. The middle lateral grooves 26 completely traverse the middle land portion 8 in the tire axial direction. As a result, the middle land portion 8 includes a plurality of middle blocks 25 that are divided into the plurality of middle lateral grooves 26.

[0049] The axial width W5 of the middle blocks 25 is preferably smaller than the axial width W2 of the shoulder blocks 10. Specifically, the width W5 of the middle blocks 25 is 55% to 70% of the width W2 of the shoulder blocks 10. This allows the shoulder blocks 10 and middle blocks 25 to wear evenly, suppressing uneven wear.

[0050] The middle lateral grooves 26 are, for example, inclined relative to the tire axial direction. The angle θ2 of the middle lateral grooves 26 relative to the tire axial direction is larger than the angle of the shoulder lateral grooves 12 relative to the tire axial direction. In the middle lateral grooves 26 of this embodiment, the angle θ2 relative to the tire axial direction increases toward the axially inner side. The angle θ2 is, for example, 10 to 45°. As a result, the middle lateral grooves 26 are curved convexly toward one side in the tire circumferential direction (the lower side in FIG. 2). Such middle lateral grooves 26 can improve wet performance in addition to improving wear resistance and ride comfort.

[0051] The groove width W6 of the middle lateral grooves 26 is larger than, for example, the groove width W4 of the shoulder lateral grooves 12. Specifically, the groove width W6 of the middle lateral grooves 26 is 110% to 130% of the groove width W4 of the shoulder lateral grooves 12. This allows the shoulder land portions 7 and the middle land portions 8 to wear evenly, thereby suppressing uneven wear.

[0052] Figure 5 shows a cross-sectional view taken along line BB in Figure 2. As shown in Figure 5, at least one of the middle lateral grooves 26 includes at least one middle tie bar 30 with a raised groove bottom that connects two adjacent middle blocks 25. In this embodiment, one middle tie bar 30 is preferably configured in each middle lateral groove 26. The middle tie bar 30 increases the circumferential rigidity of the middle land portion 8 and helps improve wear resistance.

[0053] In this embodiment, one middle tie bar 30 is provided between both axial ends of the middle lateral groove 26. However, this is not limited to this, and multiple middle tie bars 30 may be provided in one middle lateral groove 26. The axial length L7 of the middle tie bar 30 is, for example, 40% to 55% of the axial width W5 (shown in FIG. 2) of the middle block 25. The maximum height h2 of the middle tie bar 30 is 25% to 40% of the maximum depth d2 of the middle lateral groove 26. In addition, the middle tie bar 30 in this embodiment is provided, for example, at a position that straddles the axial center of the middle lateral groove 26. This improves wear resistance and ride comfort in a well-balanced manner.

[0054] In a more preferable embodiment, when comparing the axial lengths of the tie bars at each location, the middle tie bar 30 is preferably longer than any of the inner tie bar 21, outer tie bar 22, and intermediate tie bar 23 (shown in FIG. 4) provided in the shoulder lateral grooves 12. On the other hand, the axial length L7 of the middle tie bar 30 is preferably shorter than the combined axial length of the inner tie bar 21, outer tie bar 22, and intermediate tie bar 23. This optimizes the rigidity distribution of the shoulder land portion 7 and middle land portion 8, further improving wear resistance.

[0055] As shown in FIG. 2 , each of the multiple middle blocks 25 has at least one middle sipe 28. The middle sipe 28 communicates with at least one middle lateral groove 26 on one circumferential side of the tire, and in this embodiment, it communicates with the middle lateral grooves 26 on both circumferential sides of the tire. As a result, the middle sipe 28 completely traverses the middle block 25 in the tire circumferential direction. It is also desirable that both circumferential ends of the middle sipe 28 communicate with the center portions of the middle lateral groove 26 when the middle lateral groove 26 is divided into three equal parts in the longitudinal direction. Such middle sipes 28 help to reduce the axial rigidity of the middle block 25 and improve ride comfort.

[0056] The middle sipes 28 are, for example, inclined relative to the tire circumferential direction. The middle sipes 28 are desirably inclined in the same direction as the shoulder sipes 15. The angle θ3 between the middle sipes 28 and the middle lateral grooves 26 is, for example, 75 to 90°. Such middle sipes 28 are useful for improving wear resistance and ride comfort in a well-balanced manner.

[0057] 5, it is desirable that the middle sipes 28 communicate with the middle lateral grooves 26 at the same positions as the middle tie bars 30. This allows the connection between the middle lateral grooves 26 and the middle sipes 28 to be reinforced by the middle tie bars 30, suppressing uneven wear around the connection.

[0058] 2, each middle block 25 of this embodiment is not provided with any grooves or sipes except for the above-mentioned middle sipe 28. This can further enhance the above-mentioned effects.

[0059] Fig. 6 shows an enlarged view of the crown land portion 9. As shown in Fig. 6, the width W7 of the crown land portion 9 in the tire axial direction is, for example, 10% to 20% of the tread width TW. Furthermore, the width W7 of the crown land portion 9 is desirably smaller than the width W2 of the shoulder block 10 in the tire axial direction.

[0060] The crown land portion 9 is provided with a plurality of first crown lateral grooves 36 and a plurality of second crown lateral grooves 37. The first crown lateral grooves 36 extend from a crown circumferential groove 6 arranged on one axial side (left side in FIG. 6 ) of the crown land portion 9 toward the tire equator C and terminate within the crown land portion 9. The second crown lateral grooves 37 extend from a crown circumferential groove 6 arranged on the other axial side (right side in FIG. 6 ) of the crown land portion 9 toward the tire equator C and terminate within the crown land portion 9. The first crown lateral grooves 36 and the second crown lateral grooves 37 can improve wet performance while maintaining the rigidity of the crown land portion 9.

[0061] In order to improve wear resistance and ride comfort in a well-balanced manner, the axial length L8 of the first crown lateral groove 36 or the second crown lateral groove 37 is preferably 45% to 55% of the axial width W7 of the crown land portion 9.

[0062] The first crown lateral grooves 36 are curved so as to be convex toward one side in the tire circumferential direction (upper side in FIG. 6), and the second crown lateral grooves 37 are curved so as to be convex toward the other side in the tire circumferential direction (lower side in FIG. 6). This further suppresses uneven wear of the crown land portion 9.

[0063] As shown in Figure 1, the first crown lateral grooves 36 and the middle lateral grooves 26 adjacent to the first crown lateral grooves 36 on the first tread edge T1 side are curved convexly in opposite directions. Also, the second crown lateral grooves 37 and the middle lateral grooves 26 adjacent to the second crown lateral grooves 37 on the second tread edge T2 side are curved convexly in opposite directions. This arrangement of lateral grooves ensures that the wear of each land portion progresses uniformly, suppressing uneven wear of each land portion.

[0064] 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]

[0065] A pneumatic tire of size 235 / 60R17C having the basic pattern of FIG. 1 was prototyped based on the specifications in Table 1. A comparative tire having the pattern shown in FIG. 7 was also prototyped. As shown in FIG. 7, the comparative tire has no sipes in the shoulder land portion a, and no tie bars in the shoulder lateral grooves b. Except for the above-mentioned features, the comparative tire is substantially the same as the example tire. Furthermore, these test tires were tested for wear resistance and ride comfort. The common specifications and test methods for each test tire are as follows: Rim: 17 x 6.0J Tire pressure: 525kPa on all wheels Test vehicle: 3000cc, four-wheel drive Tire mounting position: All wheels

[0066] <Wear resistance> After driving the test vehicle for a certain distance (30,000 km) on ordinary roads and expressways, the remaining height of the shoulder blocks (remaining groove depth of the shoulder lateral grooves) was measured. The results were expressed as an index, with the remaining height of the comparative example being 100. The higher the index, the better the wear resistance of the shoulder blocks.

[0067] <Ride comfort> The test vehicle was driven on ordinary roads and expressways and the ride comfort was evaluated by the driver. The results are rated based on the ride comfort of the comparative example, with the score being 100. The higher the score, the better the ride comfort. The test results are shown in Table 1.

[0068] [Table 1]

[0069] As a result of the test, it was confirmed that the tires of the examples exhibited excellent ride comfort while maintaining the wear resistance of the blocks.

[0070] [Note] The present disclosure includes the following aspects.

[0071] [Disclosure 1] A tire having a tread portion, the tread portion includes a first tread edge, a shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a shoulder land portion including the first tread edge and divided by the shoulder circumferential groove, The shoulder land portion is provided with a plurality of shoulder lateral grooves extending from the shoulder circumferential groove to at least the first tread edge, the shoulder land portion includes a plurality of shoulder blocks divided by the plurality of shoulder lateral grooves, Each of the plurality of shoulder blocks is provided with at least one shoulder sipe that communicates with the shoulder lateral groove and terminates within the shoulder block, At least one of the shoulder lateral grooves includes at least one tie bar having a raised groove bottom portion so as to connect two adjacent shoulder blocks. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the tie bars include an inner tie bar provided axially inward of the axial center position of the shoulder lateral groove. [Disclosure 3] The tire according to Disclosure 1 or 2, wherein the tie bars include an outer tie bar provided axially outward of the axial center position of the shoulder lateral groove. [Disclosure 4] The tire according to any one of Disclosures 1 to 3, wherein the tie bars include an intermediate tie bar provided between both axial end portions of the shoulder lateral groove. [Disclosure 5] At least one of the shoulder lateral grooves includes a plurality of the tie bars, The tire according to any one of Disclosures 1 to 4, wherein the shoulder sipe is in communication with the shoulder lateral groove at the same position as one of the plurality of tie bars. [Disclosure 6] The tie bars include an intermediate tie bar provided between both end portions of the shoulder lateral groove in the tire axial direction, The tire according to any one of Disclosures 1 to 5, wherein the shoulder sipe communicates with the shoulder lateral groove at the same position as the intermediate tie bar. [Disclosure 7] A tire described in any one of Disclosures 1 to 6, wherein the shoulder sipes include a first shoulder sipe that communicates with the shoulder lateral groove arranged on one side of the shoulder block in the tire circumferential direction, and a second shoulder sipe that communicates with the shoulder lateral groove arranged on the other side of the shoulder block in the tire circumferential direction. [Disclosure 8] The tire according to Disclosure 7, wherein the first shoulder sipes and the second shoulder sipes are inclined in the same direction relative to the tire circumferential direction. [Disclosure 9] The tire according to Disclosure 7 or 8, wherein a connection portion between the shoulder lateral groove and the second shoulder sipe is offset in the tire axial direction from a connection portion between the shoulder lateral groove and the first shoulder sipe. [Disclosure 10] The tire according to any one of Present Disclosures 1 to 9, wherein the length of the shoulder sipe in the tire circumferential direction is 25% to 35% of the length of the shoulder block in the tire circumferential direction. [Disclosure 11] The tire according to any one of Disclosures 1 to 10, wherein the angle between the shoulder lateral groove and the shoulder sipe is 50 to 80°. [Disclosure 12] the tread portion includes a middle land portion adjacent to the shoulder land portion via the shoulder circumferential groove, The middle land portion is provided with a plurality of middle lateral grooves that completely cross the middle land portion in the tire axial direction, the middle land portion includes a plurality of middle blocks that are divided into the plurality of middle lateral grooves, The tire according to any one of Disclosures 1 to 11, wherein at least one of the middle lateral grooves includes at least one middle tie bar having a raised groove bottom portion so as to connect two adjacent middle blocks. [Disclosure 13] Each of the plurality of middle blocks is provided with at least one middle sipe communicating with the middle lateral groove, The tire according to the present disclosure 12, wherein the middle sipe is in communication with the middle lateral groove at the same position as the middle tie bar. [Disclosure 14] The tire of disclosure 13, wherein the middle sipe completely traverses the middle block in the tire circumferential direction. [Explanation of symbols]

[0072] 2 Tread section 5 Shoulder circumferential groove 7 Shoulder Land Section 10 Shoulder Block 12 Shoulder groove 15 Shoulder sipes 20 tie bars T1 First tread edge

Claims

1. A tire having a tread portion, the tread portion includes a first tread edge, a shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a shoulder land portion including the first tread edge and divided by the shoulder circumferential groove, a plurality of shoulder lateral grooves extending from the shoulder circumferential groove to at least the first tread edge are provided in the shoulder land portion, the shoulder land portion includes a plurality of shoulder blocks divided by the plurality of shoulder lateral grooves, Each of the plurality of shoulder blocks is provided with at least one shoulder sipe that communicates with the shoulder lateral groove and terminates within the shoulder block, At least one of the shoulder lateral grooves includes at least one tie bar having a raised groove bottom portion so as to connect two adjacent shoulder blocks, the tread portion includes a middle land portion adjacent to the shoulder land portion via the shoulder circumferential groove, The middle land portion is provided with a plurality of middle lateral grooves that completely cross the middle land portion in the tire axial direction, the middle land portion includes a plurality of middle blocks that are divided into the plurality of middle lateral grooves, At least one of the middle lateral grooves includes at least one middle tie bar having a raised groove bottom portion so as to connect two adjacent middle blocks, Each of the plurality of middle blocks is provided with at least one middle sipe communicating with the middle lateral groove, The middle sipe communicates with the middle lateral groove at the same position as the middle tie bar. tire.

2. A tire having a tread portion, the tread portion includes a first tread edge, a shoulder circumferential groove adjacent to the first tread edge and extending continuously in the tire circumferential direction, and a shoulder land portion including the first tread edge and divided by the shoulder circumferential groove, a plurality of shoulder lateral grooves extending from the shoulder circumferential groove to at least the first tread edge are provided in the shoulder land portion, the shoulder land portion includes a plurality of shoulder blocks divided by the plurality of shoulder lateral grooves, Each of the plurality of shoulder blocks is provided with at least one shoulder sipe that communicates with the shoulder lateral groove and terminates within the shoulder block, At least one of the shoulder lateral grooves includes at least one tie bar having a raised groove bottom portion so as to connect two adjacent shoulder blocks, The tie bars include an intermediate tie bar provided between both end portions of the shoulder lateral groove in the tire axial direction, The shoulder sipe communicates with the shoulder lateral groove at the same position as the intermediate tie bar, the shoulder sipes include a first shoulder sipe communicating with the shoulder lateral groove arranged on one side of the shoulder block in the tire circumferential direction, and a second shoulder sipe communicating with the shoulder lateral groove arranged on the other side of the shoulder block in the tire circumferential direction, a connecting portion between the shoulder lateral groove and the second shoulder sipe is offset in the tire axial direction from a connecting portion between the shoulder lateral groove and the first shoulder sipe; tire.

3. A tire as described in claim 1 or 2, wherein the tie bars include an inner tie bar arranged axially inward of the axial center position of the shoulder lateral groove.

4. A tire described in any one of claims 1 to 3, wherein the tie bars include an outer tie bar arranged axially outward of the axial center position of the shoulder lateral groove.

5. A tire as described in claim 1, wherein the tie bar includes an intermediate tie bar provided between both axial ends of the shoulder lateral groove.

6. At least one of the shoulder lateral grooves includes a plurality of the tie bars, The tire according to claim 1 , wherein the shoulder sipe communicates with the shoulder lateral groove at the same position as one of the plurality of tie bars.

7. The tie bar includes an intermediate tie bar provided between both axial ends of the shoulder lateral groove, The tire according to claim 1 , wherein the shoulder sipe communicates with the shoulder lateral groove at the same position as the intermediate tie bar.

8. A tire as described in claim 1, wherein the shoulder sipes include a first shoulder sipe communicating with the shoulder lateral groove arranged on one side of the shoulder block in the tire circumferential direction, and a second shoulder sipe communicating with the shoulder lateral groove arranged on the other side of the shoulder block in the tire circumferential direction.

9. A tire as described in claim 2 or 8, wherein the first shoulder sipe and the second shoulder sipe are inclined in the same direction relative to the tire circumferential direction.

10. A tire as described in claim 2 or 9, wherein the connection portion between the shoulder lateral groove and the second shoulder sipe is misaligned in the tire axial direction relative to the connection portion between the shoulder lateral groove and the first shoulder sipe.

11. A tire described in any one of claims 1 to 10, wherein the circumferential length of the shoulder sipes is 25% to 35% of the circumferential length of the shoulder blocks.

12. A tire described in any one of claims 1 to 11, wherein the angle between the shoulder lateral groove and the shoulder sipe is 50 to 80 degrees.

13. A tire as described in claim 1, wherein the middle sipe completely traverses the middle block in the circumferential direction of the tire.

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