tire

Abstract

To provide a tire in which operation stability and noise performance are improved.SOLUTION: Provided is a tire that includes a tread portion 2 having a designated mounting direction to a vehicle. An outer shoulder land portion 11 has the greatest width in a tire axial direction of a ground contact surface among five land portions 4. The outer shoulder land portion 11 includes a plurality of outer shoulder sipes 42 connected to an outer shoulder circumferential groove 6. An outer middle land portion 13 includes a plurality of outer middle sipes 16 extending completely across the outer middle land portion 13 in the tire axial direction. The outer shoulder sipes 42 and the outer middle sipes 16 each include a pair of sipe walls. The outer shoulder sipes 42 and the outer middle sipes 16 each include a body portion in which the pair of sipe walls are disposed substantially parallel to each other. The width of the body portion of each outer shoulder sipe 42 is greater than the width of the body portion of each outer middle sipe 16.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below proposes a pneumatic tire provided with a plurality of middle lateral grooves in an inner middle land portion and an outer middle land portion. By defining the pitch interval of the middle lateral grooves, the pneumatic tire is expected to improve handling stability and noise performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the recent improvement in performance and high output of vehicles, further improvement in handling stability of tires is required. On the other hand, improvement in noise performance of tires is also required. Especially in Europe, the regulations on vehicle exterior noise have been tightened, and tires that can meet these requirements are needed.

[0005] The present disclosure has been devised in view of the above actual situation, and the main problem is to provide a tire with improved handling stability and noise performance.

Means for Solving the Problems

[0006] This disclosure relates to a tire having a tread portion for which the orientation of mounting to a vehicle is specified, wherein the tread portion includes an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, four circumferential grooves extending continuously in the circumferential direction of the tire between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves, wherein the four circumferential grooves include an outer shoulder circumferential groove located closest to the outer tread end when mounted on the vehicle, and the five land portions include an outer shoulder land portion including the outer tread end and an outer middle land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove, The outer shoulder land portion has the largest width in the axial direction of the contact surface among the five land portions, the outer shoulder land portion is provided with a plurality of outer shoulder sipes communicating with the outer shoulder circumferential groove, the outer middle land portion is provided with a plurality of outer middle sipes communicating with the outer shoulder circumferential groove, each of the outer shoulder sipes and the outer middle sipes includes a pair of sipe walls, each of the outer shoulder sipes and the outer middle sipes includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other, and the width of the main body portion of the outer shoulder sipe is greater than the width of the main body portion of the outer middle sipe. [Effects of the Invention]

[0007] The tire disclosed herein can improve handling stability and noise performance by adopting the above configuration. [Brief explanation of the drawing]

[0008] [Figure 1] This is an exploded view of the tread portion showing one embodiment of the present disclosure. [Figure 2] Figure 1 shows enlarged views of the outer shoulder and outer middle land areas. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] Figure 2 is a cross-sectional view along line BB. [Figure 5] Figure 2 is a cross-sectional view along the CC line. [Figure 6] Figure 2 is a cross-sectional view along the DD line. [Figure 7] This is a cross-sectional view along the EE line in Figure 2. [Figure 8] Figure 1 shows enlarged views of the inner middle and inner shoulder areas of the land. [Figure 9] Figure 1 is an enlarged view of the Crown Land area. [Figure 10] Figure 1 is a plan view showing the shape of the tire's contact surface. [Figure 11] This is an exploded view of the tread portion of another embodiment of the present disclosure. [Figure 12] This is an exploded view of the tread portion of another embodiment of the present disclosure. [Figure 13] Figure 12 shows enlarged views of the outer shoulder and outer middle land areas. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. Figure 1 is an exploded view of the tread portion 2 of a tire 1 showing one embodiment of the present disclosure. The tire 1 of this embodiment is suitably used, for example, as a pneumatic tire for a passenger car. However, the present disclosure is not limited to this embodiment and may also be applied to pneumatic tires for heavy loads or non-pneumatic tires in which pressurized air is not filled inside the tire.

[0010] As shown in Figure 1, the tread portion 2 of the present disclosure includes four circumferential grooves 3 that extend continuously in the circumferential direction of the tire between two tread ends, and five land portions 4 divided into the four circumferential grooves 3. That is, the tire 1 of the present disclosure is configured as a so-called five-rib tire in which the tread portion 2 is composed of five land portions 4.

[0011] The tread portion 2 of the present disclosure has a specified direction of attachment to the vehicle. Accordingly, the two tread ends include an inner tread end Ti that becomes the inner side of the vehicle when the tire 1 is attached to the vehicle, and an outer tread end To that becomes the outer side of the vehicle when the tire is attached to the vehicle. The direction of attachment to the vehicle is indicated, for example, by letters or symbols on a sidewall portion (not shown).

[0012] The inner tread end Ti and the outer tread end To respectively correspond to the outermost ground contact positions in the tire axial direction when a normal load is applied to the normal tire 1 and the tire is grounded on a plane with a camber angle of 0°.

[0013] The "normal state" means that in the case of a pneumatic tire with various standards defined, the tire is rim-mounted on a normal rim and filled with a normal internal pressure, and moreover, it is in a non-loaded state. In the case of a tire without various defined standards or a non-pneumatic tire, the "normal state" means a standard use state according to the purpose of use of the tire, which is a state where the tire is not mounted on a vehicle and is non-loaded. In this specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the above normal state.

[0014] The "normal rim" is the rim defined for each tire in a standard system including the standards on which the tire is based. For example, in JATMA, it is the "standard rim", in TRA, it is the "Design Rim", and in ETRTO, it is the "Measuring Rim".

[0015] The "normal internal pressure" is the air pressure defined for each tire in a standard system including the standards on which the tire is based. In JATMA, it is the "maximum air pressure", in TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is the "INFLATION PRESSURE".

[0016] For pneumatic tires with various standards, the "normal load" is the load specified for each tire in the standard system including the standards on which the tire is based. For JATMA, it is the "maximum load capacity"; for TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; for ETRTO, it is the "LOAD CAPACITY". For tires without various standards or non-pneumatic tires, the "normal load" refers to the load acting on one tire in the standard mounting state of the tire. The "standard mounting state" refers to the state where the tire is mounted on a standard vehicle according to the purpose of use of the tire and the vehicle is stationary on a flat road surface in a state where it can run.

[0017] The four circumferential grooves 3 include the outer shoulder circumferential groove 6 located on the outermost tread end To side. Further, the four circumferential grooves 3 of the present embodiment include an inner shoulder circumferential groove 5, an outer crown circumferential groove 8, and an inner crown circumferential groove 7. The inner shoulder circumferential groove 5 is located on the innermost tread end Ti side. The outer crown circumferential groove 8 is provided between the outer shoulder circumferential groove 6 and the tire equator C. The inner crown circumferential groove 7 is provided between the inner shoulder circumferential groove 5 and the tire equator C.

[0018] The distance L1 in the tire axial direction from the tire equator C to the groove center line of the outer shoulder circumferential groove 6 or the inner shoulder circumferential groove 5 is preferably, for example, 25% to 35% of the tread width TW. The distance L2 in the tire axial direction from the tire equator C to the groove center line of the outer crown circumferential groove 8 or the inner crown circumferential groove 7 is preferably, for example, 5% to 15% of the tread width TW. The tread width TW is the distance in the tire axial direction from the inner tread end Ti to the outer tread end To in the normal state.

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

[0020] The groove width W1 of each circumferential groove 3 is preferably at least 3 mm. Furthermore, the groove width W1 of each circumferential groove 3 is preferably, for example, 2.0% to 8.0% of the tread width TW. In this embodiment, the outer shoulder circumferential groove 6 has the smallest groove width among the four circumferential grooves 3. However, this disclosure is not limited to this embodiment. The depth of each circumferential groove 3 is preferably, for example, 5 to 10 mm in the case of a pneumatic tire for a passenger car.

[0021] The five land sections 4 of this disclosure include an outer shoulder land section 11 and an outer middle land section 13. The outer shoulder land section 11 is located on the tire axial side of the outer shoulder circumferential groove 6 and includes the outer tread end To. The outer middle land section 13 is adjacent to the outer shoulder land section 11 via the outer shoulder circumferential groove 6. Furthermore, the five land sections 4 of this embodiment include an inner shoulder land section 10, an inner middle land section 12, and a crown land section 14. The inner shoulder land section 10 is located on the tire axial side of the inner shoulder circumferential groove 5 and includes the inner tread end Ti. The inner middle land section 12 is adjacent to the inner shoulder land section 10 via the inner shoulder circumferential groove 5. The crown land section 14 is separated between the outer crown circumferential groove 8 and the inner crown circumferential groove 7.

[0022] Figure 2 shows enlarged views of the outer shoulder land portion 11 and the outer middle land portion 13. As shown in Figure 2, in this disclosure, the outer shoulder land portion 11 has the largest width in the tire axial direction of the contact surface among the five land portions 4. The width W2 in the tire axial direction of the contact surface of the outer shoulder land portion 11 in this embodiment is, for example, 15% to 25% of the tread width TW, and preferably 15% to 20%.

[0023] The outer shoulder land portion 11 is provided with a plurality of outer shoulder sipes 42 that communicate with the outer shoulder circumferential groove 6. The outer middle land portion 13 is provided with a plurality of outer middle sipes 16 that communicate with the outer shoulder circumferential groove 6.

[0024] Figure 3 shows a cross-sectional view of the outer shoulder sipe 42 of Figure 2 along line AA. Figure 4 shows a cross-sectional view of the outer middle sipe 16 of Figure 2 along line BB. As shown in Figures 3 and 4, each of the outer shoulder sipe 42 and the outer middle sipe 16 includes a pair of sipe walls 51. Each of the outer shoulder sipe 42 and the outer middle sipe 16 also includes a main body 50 in which the pair of sipe walls 51 are arranged substantially parallel to each other. Note that "arranged substantially parallel to each other" includes not only the configuration in which the pair of sipe walls 51 extend perfectly parallel to each other, but also the configuration in which the angle between them is 5° or less.

[0025] In this specification, "sipe" refers to a notched element having a small width, wherein the width between a pair of sipe walls 51 in the main body portion 50 is 1.5 mm or less. Preferably, the width of the sipe is 0.5 to 1.5 mm. The opening of the sipe may be connected to a chamfered portion with a width exceeding 1.5 mm. The bottom of the sipe may also be connected to a flask bottom with a width exceeding 1.5 mm.

[0026] As shown in Figures 3 and 4, in this disclosure, the width W3 of the main body 50 of the outer shoulder sipe 42 is greater than the width W4 of the main body 50 of the outer middle sipe 16. By adopting the above configuration, this disclosure can improve handling stability and noise performance. The following mechanism is presumed to be the reason for this.

[0027] As shown in Figure 2, in this disclosure, the outer shoulder land portion 11 has the largest width in the axial direction of the contact surface among the five land portions, resulting in a large cornering force being generated in the outer shoulder land portion 11 and improved handling stability.

[0028] Furthermore, the outer shoulder sipes 42 and outer middle sipes 16 reduce the rigidity of the outer shoulder land portion 11 and outer middle land portion 13, thereby reducing impact noise upon ground contact. This improves noise performance.

[0029] Furthermore, as shown in Figures 3 and 4, in this disclosure, the width W3 of the main body 50 of the outer shoulder sipe 42 is greater than the width W4 of the main body 50 of the outer middle sipe 16. This optimizes the rigidity balance of the outer shoulder land portion 11 and the outer middle land portion 13, further improving handling stability. In addition, the different widths of the main body portions 50 of the outer shoulder sipe 42 and the outer middle sipe 16 can convert the pitch noise they generate into white noise, potentially improving noise performance. It is presumed that the tire of this disclosure can improve handling stability and noise performance through the above mechanism.

[0030] As shown in Figure 3, from the viewpoint of improving handling stability and noise performance in a balanced manner, the width W3 of the main body 50 of the outer shoulder sipe 42 is, for example, 0.6 to 1.0 mm. As shown in Figure 4, the width W4 of the main body 50 of the outer middle sipe 16 is, for example, 0.4 to 0.8 mm. Furthermore, the width W3 is preferably 115% to 150% of the width W4, and more preferably 125% to 140%.

[0031] The configuration of this embodiment will be described in more detail below. Note that each configuration described below represents a specific aspect of this embodiment. Therefore, it goes without saying that this disclosure can achieve the above-described effects even without the configurations described below. Furthermore, even if any one of the configurations described below is applied individually to a tire of this disclosure having the above-described features, an improvement in performance corresponding to each configuration can be expected. Moreover, if several of the configurations described below are applied in combination, a combined improvement in performance corresponding to each configuration can be expected.

[0032] As shown in Figure 2, the outer shoulder sipe 42 of this embodiment extends, for example, from the outer shoulder circumferential groove 6 and has an end that closes within the outer shoulder land portion 11 without reaching the outer tread end To. Hereinafter, this end may be referred to as the interrupted end 42a. The length L3 of the outer shoulder sipe 42 in the tire axial direction is, for example, 40% to 60% of the width W2 in the tire axial direction of the contact surface of the outer shoulder land portion 11.

[0033] The outer shoulder sipe 42 is inclined downward to the right with respect to the tire axis, for example. Hereafter, this direction of inclination may be referred to as "inclined in a first direction with respect to the tire axis." The angle of the outer shoulder sipe 42 with respect to the tire axis is, for example, 5 to 15°. Such an outer shoulder sipe 42 can maintain wet performance while suppressing uneven wear of the outer shoulder land portion 11.

[0034] As shown in Figure 3, in this embodiment, the outer shoulder sipe 42 is formed by chamfered portions 43 on at least one of the sipe edges on both sides, and in this embodiment, both. The chamfered portion 43 in this embodiment is, for example, an inclined surface 52a extending between the ground contact surface and the sipe wall 51 in the main body portion 50 of the sipe. As shown in Figure 2, in a more preferred embodiment, the chamfered portion 43 of the outer shoulder sipe 42 has a chamfered width that increases from the side of the interrupted end 42a toward the side of the outer shoulder circumferential groove 6. This equalizes the ground pressure acting on the outer shoulder ground portion 11, improving steering stability and noise performance.

[0035] The chamfer width of the chamfered portion 43 of the outer shoulder sipe 42 increases continuously, for example, from the side of the interrupted end 42a toward the side of the outer shoulder circumferential groove 6. The maximum chamfer width W5 of the chamfered portion 43 is, for example, 2.0 to 4.0 mm. The maximum depth of the chamfered portion 43 is, for example, 1.0 to 2.0 mm. In this embodiment, the maximum chamfer width W5 is formed at the end of the outer shoulder sipe 42 on the side of the outer shoulder circumferential groove 6.

[0036] Figure 5 shows a cross-sectional view of the CC line in Figure 2. As shown in Figure 5, the outer shoulder sipe 42 includes a first portion 46 located on the outer shoulder circumferential groove 6 side and a second portion 47 located on the interrupted end 42a side and having a smaller depth than the first portion 46. The depth d2 of the second portion 47 is, for example, 60% to 75% of the depth d1 of the first portion 46. In this embodiment, the first portion 46 constitutes the maximum depth of the outer shoulder sipe 42. The maximum depth of the outer shoulder sipe 42 is, for example, 3.5 to 5.0 mm. In this embodiment, the maximum depth of the outer shoulder sipe 42 is greater than the maximum depth of the outer middle sipe 16. Such an outer shoulder sipe 42 helps to improve steering stability and noise performance in a balanced manner.

[0037] As shown in Figure 2, the outer shoulder land portion 11 of this embodiment is provided with a plurality of outer shoulder lateral grooves 41. In this embodiment, the outer shoulder lateral grooves 41 and outer shoulder sipes 42 are arranged alternately in the circumferential direction of the tire.

[0038] The outer shoulder lateral groove 41 extends from the outer shoulder circumferential groove 6 to a position beyond the outer tread edge To. The outer shoulder lateral groove 41 is inclined, for example, in the first direction with respect to the tire axis. The angle of the outer shoulder lateral groove 41 with respect to the tire axis is, for example, 5 to 15°. The angle difference between the outer shoulder sipe 42 and the outer shoulder lateral groove 41 is preferably 10° or less, and in this embodiment, they extend parallel to each other. Such an outer shoulder lateral groove 41 can improve wet performance while suppressing uneven wear of the outer shoulder land portion 11.

[0039] Figure 6 shows a cross-sectional view of line DD in Figure 2. As shown in Figure 6, the outer shoulder lateral groove 41 includes a tie bar 48 with a locally raised groove bottom. The minimum depth d4 from the contact surface of the outer shoulder land portion 11 to the outer surface of the tie bar 48 is 40% to 60% of the maximum depth d3 of the outer shoulder lateral groove 41. Such a tie bar 48 can improve noise performance and braking performance while maintaining wet performance.

[0040] As shown in Figure 2, the outer middle sipe 16 of this embodiment completely traverses the outer middle land portion 13 in the tire axis direction. The outer middle sipe 16 is inclined, for example, upward to the right with respect to the tire axis direction. Hereinafter, this direction of inclination may be referred to as "inclined in a second direction with respect to the tire axis direction." In a desirable embodiment, the angle of the outer middle sipe 16 with respect to the tire axis direction is greater than the angle of the outer shoulder sipe 42 with respect to the tire axis direction. Specifically, the angle of the outer middle sipe 16 with respect to the tire axis direction is 20 to 30°. Such an outer middle sipe 16 can also provide frictional force in the tire axis direction when driving in wet conditions.

[0041] The outer middle sipe 16 has chamfered edges on at least one side, in this embodiment both sides, formed by chamfered portions 55.

[0042] The chamfered portion 55 of the outer middle sipe 16 includes, for example, a fixed-width portion 55a, an inner widened portion 55b, and an outer widened portion 55c. The fixed-width portion 55a extends in the sipe length direction with a constant chamfer width. The inner widened portion 55b is connected to the outer crown circumferential groove 8 side of the fixed-width portion 55a, and the chamfer width increases from the fixed-width portion 55a to the outer crown circumferential groove 8. The outer widened portion 55c is connected to the outer shoulder circumferential groove 6 side of the fixed-width portion 55a, and the chamfer width increases from the fixed-width portion 55a to the outer shoulder circumferential groove 6. As a result, the chamfered portion 55 of the outer middle sipe 16 has its minimum chamfer width at a position away from the longitudinal edges on both sides of the outer middle land portion 13, and the chamfer width increases toward both sides in the tire axial direction from the position of the minimum chamfer width. The outer middle sipe 16 having such a chamfered portion 55 makes it easier to equalize the ground pressure acting on the outer middle land portion 13, which helps to further improve steering stability.

[0043] The fixed-width section 55a is positioned, for example, offset to the outer tread end To side from the center position in the tire axial direction of the outer middle land section 13. As a result, the length of the inner widened section 55b in the tire axial direction is greater than the length of the outer widened section 55c in the tire axial direction. Specifically, the length L4 of the inner widened section 55b is 40% to 60% of the width W6 of the contact surface of the outer middle land section 13. The length L5 of the outer widened section 55c is 25% to 35% of the width W6 of the contact surface of the outer middle land section 13. As a result, even if the contact pressure acting on the outer middle land section 13 changes, excellent handling stability and noise performance are reliably achieved.

[0044] Figure 7 shows a cross-sectional view of line EE in Figure 2. As shown in Figure 7, the maximum depth d5 ​​of the inner widened portion 55b is greater than the maximum depth d6 of the outer widened portion 55c. Specifically, the depth d6 of the outer widened portion 55c is 20% to 60% of the depth d5 ​​of the inner widened portion 55b. Furthermore, the depth d5 ​​of the inner widened portion 55b and the depth d6 of the outer widened portion 55c are, for example, 0.5 to 3.0 mm. In addition, the minimum depth of the chamfered portion 20 is, for example, 0.3 to 1.0 mm.

[0045] The outer middle sipe 16 includes, for example, a middle tie bar 25 with a locally raised bottom. The middle tie bar 25 is positioned, for example, in the central region when the outer middle sipe 16 is divided into three equal parts in the tire axial direction. The tire axial length L6 of the middle tie bar 25 is 30% to 50% of the tire axial width W6 (shown in Figure 2) of the contact surface of the outer middle turret 13. The depth d8 from the contact surface of the outer middle turret 13 to the outer surface of the middle tie bar 25 is 50% to 70% of the maximum depth d7 of the outer middle sipe 16. Such a middle tie bar 25 helps maintain the rigidity of the outer middle turret 13 and provide a large cornering force. The maximum depth of the outer middle sipe 16 is, for example, 3.0 to 5.0 mm.

[0046] Figure 8 shows enlarged views of the inner middle land portion 12 and the inner shoulder land portion 10. As shown in Figure 8, the inner middle land portion 12 is provided with a number of inner middle sipes 17 that completely traverse the inner middle land portion 12 in the direction of the tire axis.

[0047] The width of the main body of the inner middle sipe 17 is, for example, 0.4 to 0.8 mm. The maximum depth of the inner middle sipe 17 is, for example, 3.0 to 5.0 mm. The inner middle sipe 17 is inclined in the second direction with respect to the tire axis, for example. The angle of the inner middle sipe 17 with respect to the tire axis is, for example, 20 to 30°. Such an inner middle sipe 17 can also provide friction in the tire axis direction during wet driving.

[0048] The inner middle sipe 17 has chamfered portions 56 formed on each of its sipe edges. The chamfered portion 56 of the inner middle sipe 17 includes, for example, a fixed width portion 56a, an inner widened portion 56b connected to the inner crown circumferential groove 7 side of the fixed width portion 56a, and an outer widened portion 56c connected to the inner shoulder circumferential groove 5 side of the fixed width portion 56a. The configuration of the fixed width portion 55a, inner widened portion 55b, and outer widened portion 55c of the chamfered portion 55 of the outer middle sipe 16 (shown in Figure 2) can be applied to the fixed width portion 56a, inner widened portion 56b, and outer widened portion 56c of the inner middle sipe 17, and a further explanation is omitted here.

[0049] The inner shoulder land portion 10 is provided with a plurality of inner shoulder lateral grooves 35 and a plurality of inner shoulder sipes 36. In this embodiment, these are arranged alternately in the circumferential direction of the tire.

[0050] The inner shoulder lateral groove 35 extends from its inner end 35a, located between the inner tread edge Ti and the inner shoulder circumferential groove 5, to a position beyond the inner tread edge Ti. The inner shoulder lateral groove 35 crosses, for example, the axial center of the contact surface of the inner shoulder land portion 10. The axial length L7 of the inner shoulder lateral groove 35 at the contact surface of the inner shoulder land portion 10 is, for example, 70% to 90% of the axial width W7 of the contact surface of the inner shoulder land portion 10. Such an inner shoulder lateral groove 35 helps to improve braking performance while maintaining wet performance.

[0051] The inner shoulder lateral groove 35 is inclined in the first direction with respect to the tire axis, for example. The angle of the inner shoulder lateral groove 35 with respect to the tire axis is, for example, 5 to 15°. Such an inner shoulder lateral groove 35 can guide the water inside towards the inner tread edge Ti during wet driving, exhibiting excellent drainage performance.

[0052] The inner shoulder sipe 36 communicates with at least the inner shoulder circumferential groove 5, and in this embodiment, extends from the inner shoulder circumferential groove 5 to a position beyond the inner tread edge Ti. The inner shoulder sipe 36 extends linearly, for example, inclined in the first direction with respect to the tire axis. The angle of the inner shoulder sipe 36 with respect to the tire axis is, for example, 5 to 15°. The angle difference between the inner shoulder sipe 36 and the inner shoulder lateral groove 35 is preferably 10° or less, and in this embodiment, they extend parallel to each other. Such an inner shoulder sipe 36 can improve noise performance and ride comfort while suppressing uneven wear of the inner shoulder land portion 10.

[0053] It is preferable that the inner shoulder sipe 36 does not have a chamfered portion. That is, the inner shoulder sipe 36 has a sipe wall that is directly connected to the contact surface of the inner shoulder land portion 10 and extends along the radial direction of the tire. Such an inner shoulder sipe 36 can provide a large frictional force during wet driving due to its edge.

[0054] The width of the main body of the inner shoulder sipe 36 is, for example, 0.6 to 1.0 mm. In a more desirable embodiment, the width of the main body of the inner shoulder sipe 36 is greater than the width of the main body of the inner middle sipe 17. The maximum depth of the inner shoulder sipe 36 is 4.0 to 5.5 mm. This further improves handling stability and noise performance.

[0055] In this embodiment, the inner shoulder land portion 10 is provided with auxiliary sipes 37 that extend from the inner shoulder circumferential groove 5 to the inner end 35a of the inner shoulder transverse groove 35. Such auxiliary sipes 37 help maintain wet performance.

[0056] Figure 9 shows an enlarged view of the crown land area 14 in Figure 1. As shown in Figure 9, the crown land area 14 has its center in the axial direction located on the outer tread edge To (shown in Figure 1) side of the tire equator C. As a result, in the crown land area 14, the width W8b of the contact patch in the outer region 14b on the outer tread edge To side of the tire equator C is greater than the width W8a of the contact patch in the inner region 14a on the inner tread edge Ti side of the tire equator C. Specifically, the width W8b of the outer region 14b is 51% to 55% of the width W8 of the contact patch of the crown land area 14. Such a crown land area 14 helps to linearize the change in cornering force with changes in steering angle, thereby improving handling stability and ride comfort.

[0057] The crown ridge 14 is provided with a plurality of first crown sipes 31 and a plurality of second crown sipes 32. The first crown sipes 31 extend, for example, from the inner crown circumferential groove 7 and are interrupted within the crown ridge 14. The second crown sipes 32 extend, for example, from the outer crown circumferential groove 8 and are interrupted within the crown ridge 14. The width of the main body of the first crown sipes 31 and second crown sipes 32 is, for example, 0.5 to 1.5 mm. The maximum depth of the first crown sipes 31 and second crown sipes 32 is 4.0 to 6.0 mm. Such first crown sipes 31 and second crown sipes 32 can reduce rolling resistance while maintaining wet performance.

[0058] To ensure the effects described above are achieved, the first crown sipe 31 and the second crown sipe 32 do not cross the center position of the crown land area 14 in the tire axial direction, nor do they cross the tire equator C. The length L8 of the first crown sipe 31 or the second crown sipe 32 in the tire axial direction is, for example, 15% to 30% of the width W8 of the contact surface of the crown land area 14 in the tire axial direction.

[0059] The first crown sipe 31 and the second crown sipe 32 are inclined, for example, in the second direction with respect to the tire axis. The angle of the first crown sipe 31 or the second crown sipe 32 with respect to the tire axis is, for example, 20 to 30°. In a more desirable embodiment, the angle difference between the first crown sipe 31 or the second crown sipe 32 and the outer middle sipe 16 is 10° or less. This suppresses uneven wear of the crown land portion 14.

[0060] Figure 10 shows the contact surface shape when 50% of the normal load is applied to the tire 1 in the normal state (hereinafter sometimes referred to as the "50% load state"). As shown in Figure 8, in the 50% load state, it is desirable that the width W11 in the tire axial direction of the contact surface of the outer shoulder land area 11 is 114% to 124% of the width W10 in the tire axial direction of the contact surface of the crown land area 14.

[0061] Similarly, the width W12 in the axial direction of the contact surface of the outer middle land portion 13 is preferably 85% to 115% of the width W10 in the axial direction of the contact surface of the crown land portion 14. Furthermore, the width W12 in the axial direction of the contact surface of the outer middle land portion 13 is preferably greater than the width W13 in the axial direction of the contact surface of the inner middle land portion 12. Specifically, the width W12 of the outer middle land portion 13 is preferably 105% to 115% of the width W13 of the inner middle land portion 12. In addition, the width W13 in the axial direction of the contact surface of the inner middle land portion 12 and the width W14 in the axial direction of the contact surface of the inner shoulder land portion 10 are preferably 80% to 100% of the width W10 in the axial direction of the contact surface of the crown land portion 14. As a result, when the tire 1 of this embodiment is applied to all wheels of a vehicle, the front and rear wheels can exert cornering force in a balanced manner, and consequently, excellent handling stability is achieved.

[0062] Figure 11 shows an exploded view of the tread portion 2 in another embodiment of the present disclosure. As shown in Figure 11, in this embodiment, the outer middle sipe 16 and the first crown sipe 31 and second crown sipe 32 are inclined in the first direction with respect to the tire axis, compared to the embodiment shown in Figure 1. Such embodiments help to increase the conicity of the tire. The embodiment in Figure 11 can be adapted to the configurations included in the embodiments shown in Figures 1 to 10.

[0063] Figure 12 shows an exploded view of the tread portion 2 of another embodiment of the present disclosure. Figure 13 shows an enlarged view of the outer shoulder portion 11 and outer middle portion 13 of the embodiment shown in Figure 12. As shown in Figures 12 and 13, the outer middle sipe 16 of this embodiment has an end that closes within the outer middle portion 13 without reaching the outer crown circumferential groove 8. Such an outer middle sipe 16 helps maintain the rigidity of the outer middle portion 13 and improves handling stability. Configurations not specifically described in this embodiment can be adapted from the configurations included in the embodiments shown in Figures 1 to 10.

[0064] As shown in Figure 13, the outer middle sipe 16 in this embodiment is interrupted on the side of the outer shoulder circumferential groove 6, rather than at the axial center of the contact surface of the outer middle land portion 13. The axial length L9 of the outer middle sipe 16 is, for example, 25% to 45% of the axial width W6 of the contact surface of the outer middle land portion 13. Such an outer middle sipe 16 helps to balance handling stability and wet performance.

[0065] In this embodiment, the outer middle sipe 16 has chamfered portions 55 formed on at least one, preferably both, of the sipe edges on both sides. Furthermore, the chamfer width of the chamfered portion 55 of the outer middle sipe 16 increases from the side of the interrupted end 16a toward the side of the outer shoulder circumferential groove 6. The maximum chamfer width of the chamfered portion 55 of the outer middle sipe 16 is 0.5 to 2.5 mm. Also, the maximum depth of the chamfered portion 55 is, for example, 0.5 to 2.5 mm. An outer middle sipe 16 having such a chamfered portion 55 can improve handling stability and noise performance in a balanced way.

[0066] In this embodiment, the maximum chamfer width of the chamfered portion 43 of the outer shoulder sipe 42 is, for example, 1.0 to 3.0 mm. The maximum depth of the chamfered portion 43 of the outer shoulder sipe 42 is, for example, 0.2 to 2.2 mm. In this embodiment, it is desirable that the maximum depth of the chamfered portion 55 of the outer middle sipe 16 is greater than the maximum depth of the chamfered portion 43 of the outer shoulder sipe 42. This suppresses uneven wear around the outer shoulder circumferential groove 6.

[0067] In this embodiment, the outer middle land portion 13 is provided with multiple interrupted middle sipes 57, separate from the outer middle sipes 16. The interrupted middle sipes 57 communicate with the outer crown circumferential groove 8 and have closed ends within the outer middle land portion 13 without reaching the outer shoulder circumferential groove 6. The length of the interrupted middle sipes 57 in the tire axial direction can be the same as the length of the outer middle sipes 16 described above. Such interrupted middle sipes 57, in combination with the outer middle sipes 16 described above, can further improve handling stability and noise performance.

[0068] The interrupted middle sipe 57 has chamfered portions 58 formed on at least one, preferably both, of its sipe edges. The chamfered portion 58 of the interrupted middle sipe 57 has a wider chamfer width from the side of the interrupted end 57a toward the side of the outer shoulder circumferential groove 6. In a more desirable embodiment, the maximum chamfer width of the chamfered portion of the interrupted middle sipe 57 is greater than the maximum chamfer width of the chamfered portion 55 of the outer middle sipe 16. Also, the maximum depth of the chamfered portion 58 of the interrupted middle sipe 57 is greater than the maximum depth of the chamfered portion 55 of the outer middle sipe 16. This suppresses uneven wear of the outer middle land portion 13.

[0069] In this embodiment, the outer middle land portion 13 is provided with a single outer middle longitudinal sipe 59 that extends continuously in the circumferential direction of the tire. Preferably, the outer middle longitudinal sipe 59 is positioned in the central region when the contact surface of the outer middle land portion 13 is divided into three equal parts in the axial direction of the tire. Furthermore, the outer middle longitudinal sipe 59 extends at an angle of 5° or less with respect to the circumferential direction of the tire, and more specifically, extends linearly parallel to the circumferential direction of the tire. In another embodiment, the outer middle longitudinal sipe 59 may extend in a zigzag pattern. Such an outer middle longitudinal sipe 59 can provide frictional force in the axial direction of the tire and improve turning performance.

[0070] As shown in Figure 12, the inner middle land section 12 of this embodiment is provided with a first inner middle sipe 61, a second inner middle sipe 62, and an inner middle vertical sipe 63. The configuration of the interrupted middle sipe 57 provided on the outer middle land section 13 described above can be applied to the first inner middle sipe 61. The configuration of the outer middle sipe 16 of the embodiment shown in Figure 12 can be applied to the second inner middle sipe 62. The configuration of the outer middle vertical sipe 59 can be applied to the inner middle vertical sipe 63.

[0071] 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 specific embodiment described above and can be implemented in various modified forms. [Examples]

[0072] A 235 / 45R19 size tire with the basic pattern shown in Figure 1 was prototyped based on the specifications in Table 1. As a comparative example, a tire was also prototyped in which the width of the outer shoulder sipe and the width of the outer middle sipe were the same. Except for the aforementioned differences, the comparative tire was substantially the same as the tire shown in Figure 1. The handling stability and noise performance of each test tire were tested. The common specifications and test methods for each test tire are as follows. Mounted rim: 19×8.0J Tire pressure: 230kPa Test vehicle: 2000cc engine, four-wheel drive Tire mounting position: All wheels

[0073] <Handling Stability> The handling stability of the above test vehicle when driven on a dry surface was evaluated subjectively by the driver. The results are scored with the handling stability of the comparative example set at 100, and a higher number indicates better handling stability.

[0074] <Noise performance> The external noise level of the test vehicle was measured when driving on a dry road at a speed of 70 km / h. The results are shown as an index with the external noise level of the comparative example set to 100, and a smaller number indicates lower and better external noise levels. The test results are shown in Table 1.

[0075] [Table 1]

[0076] As shown in Table 1, the tires of the embodiment were found to have improved handling stability and noise performance.

[0077] [Note] This disclosure includes the following aspects.

[0078] [Disclosure 1] A tire having a tread portion in which the orientation of mounting on the vehicle is specified, The tread portion includes an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, four circumferential grooves extending continuously in the circumferential direction of the tire between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves. The four circumferential grooves mentioned above include the outer shoulder circumferential groove located closest to the outermost tread edge when mounted on the vehicle. The five land portions include an outer shoulder land portion including the outer tread end, and an outer middle land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove, The aforementioned outer shoulder land portion has the largest width in the axial direction of the contact surface among the five land portions. The outer shoulder land portion is provided with a plurality of outer shoulder sipes that communicate with the outer shoulder circumferential groove, The outer middle land portion is provided with a plurality of outer middle sipes that communicate with the outer shoulder circumferential groove, Each of the outer shoulder sipe and the outer middle sipe includes a pair of sipe walls, Each of the outer shoulder sipe and the outer middle sipe includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other. The width of the main body portion of the outer shoulder sipe is greater than the width of the main body portion of the outer middle sipe. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the outer middle sipe completely traverses the outer middle land portion in the tire axial direction. [Disclosure 3] The tire according to disclosure 1 or 2, wherein the outer shoulder sipe has an end that closes within the outer shoulder land portion without reaching the outer tread edge. [Disclosure 4] The tire according to any one of disclosures 1 to 3, wherein the maximum depth of the outer shoulder sipe is greater than the maximum depth of the outer middle sipe. [Disclosure 5] The outer shoulder sipe is formed with a chamfered portion on at least one of the sipe edges on both sides. The tire according to any one of disclosures 1 to 4, wherein the chamfered portion of the outer shoulder sipe has a wider width toward the outer shoulder circumferential groove side. [Disclosure 6] The outer middle sipe completely traverses the outer middle land portion in the tire axial direction, and at least one of the sipe edges on both sides is formed with a chamfered portion. The tire according to any one of disclosures 1 to 5, wherein the chamfered portion of the outer middle sipe has a minimum chamfer width at a position away from the longitudinal edges on both sides of the outer middle land portion, and the chamfer width increases toward both sides in the tire axial direction from the position of the minimum chamfer width. [Disclosure 7] The four circumferential grooves include the inner shoulder circumferential groove located closest to the inner tread edge when mounted on the vehicle. The five land portions include an inner shoulder land portion including the inner tread end, and an inner middle land portion adjacent to the inner shoulder land portion via the inner shoulder circumferential groove, The inner shoulder land portion is provided with a plurality of inner shoulder sipes that communicate with the inner shoulder circumferential groove, The inner middle land portion is provided with a plurality of inner middle sipes that completely traverse the inner middle land portion in the direction of the tire axis, Each of the aforementioned inner shoulder sipe and inner middle sipe includes a pair of sipe walls, Each of the aforementioned inner shoulder sipe and inner middle sipe includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other. The tire according to any one of disclosures 1 to 6, wherein the width of the main body portion of the inner shoulder sipe is greater than the width of the main body portion of the inner middle sipe. [Disclosure 8] The tire according to disclosure 7, wherein the inner shoulder sipe extends beyond the inner tread edge. [Disclosure 9] The four circumferential grooves mentioned above include outer crown circumferential grooves and inner crown circumferential grooves located on both sides of the tire equator. The five land portions include a crown land portion divided between the outer crown circumferential groove and the inner crown circumferential groove, The crown land portion includes an outer region on the outer tread edge side of the tire equator and an inner region on the inner tread edge side of the tire equator, The tire according to any one of disclosures 1 to 8, wherein the width in the tire axial direction of the contact surface of the outer region is greater than the width in the tire axial direction of the contact surface of the inner region. [Disclosure 10] The tire according to disclosure 9, wherein the crown land portion is provided with a plurality of first crown sipes extending from the inner crown circumferential groove and interrupted within the contact surface of the crown land portion, and a plurality of second crown sipes extending from the outer crown circumferential groove and having closed ends within the contact surface of the crown land portion. [Disclosure 11] The four circumferential grooves mentioned above include the outer crown circumferential groove adjacent to the inner tread end side of the outer middle land portion, The tire according to Disclosure 1, wherein the outer middle sipe has an end that closes within the outer middle land portion without reaching the outer crown circumferential groove. [Disclosure 12] The aforementioned outer middle land area is provided with multiple interrupted middle sipes. The tire according to disclosure 11, wherein the interrupted middle sipe communicates with the outer crown circumferential groove and has an end that closes within the outer middle land portion without reaching the outer shoulder circumferential groove. [Disclosure 13] The tire according to disclosure 11 or 12, wherein the outer middle land portion is provided with an outer middle longitudinal sipe that extends continuously in the circumferential direction of the tire. [Disclosure 14] The outer shoulder sipe and the outer middle sipe each have at least one of their sipe edges formed with a chamfered portion. The tire according to any one of disclosures 11 to 13, wherein the maximum depth of the chamfered portion of the outer middle sipe is greater than the maximum depth of the chamfered portion of the outer shoulder sipe. [Explanation of Symbols]

[0079] 2 Tread section 3 Circumferential groove 4 Land 6. Outer shoulder circumferential groove 11 Outer shoulder land area 12 Outer Middle Track and Field 16 Outer middle sipes 42 External shoulder sipes To the outer tread edge Ti inner tread edge

Claims

1. A tire having a tread portion in which the orientation of mounting on the vehicle is specified, The tread portion includes an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, four circumferential grooves extending continuously in the circumferential direction of the tire between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves. The four circumferential grooves mentioned above include the outer shoulder circumferential groove located closest to the outermost tread edge when mounted on the vehicle. The five land portions include an outer shoulder land portion including the outer tread end, and an outer middle land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove, The aforementioned outer shoulder land portion has the largest width in the tire axial direction of the contact surface among the five land portions. The outer shoulder land portion is provided with a plurality of outer shoulder sipes that communicate with the outer shoulder circumferential groove, The outer middle land portion is provided with a plurality of outer middle sipes that communicate with the outer shoulder circumferential groove, Each of the outer shoulder sipe and the outer middle sipe includes a pair of sipe walls, Each of the outer shoulder sipe and the outer middle sipe includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other. The width of the main body portion of the outer shoulder sipe is greater than the width of the main body portion of the outer middle sipe. The outer shoulder sipe has an end that closes within the outer shoulder land portion without reaching the outer tread edge. The outer shoulder sipe is formed with a chamfered portion on each of its sipe edges. The chamfered portion of the outer shoulder sipe has a wider width toward the outer shoulder circumferential groove side. tire.

2. The tire according to claim 1, wherein the outer middle sipe completely traverses the outer middle land portion in the tire axial direction.

3. The tire according to claim 1 or 2, wherein the maximum depth of the outer shoulder sipe is greater than the maximum depth of the outer middle sipe.

4. The outer middle sipe completely traverses the outer middle land portion in the tire axial direction, and at least one of the sipe edges on both sides is formed with a chamfered portion. The tire according to any one of claims 1 to 3, wherein the chamfered portion of the outer middle sipe has a minimum chamfer width at a position away from the longitudinal edges on both sides of the outer middle land portion, and the chamfer width increases toward both sides in the tire axial direction from the position of the minimum chamfer width.

5. The four circumferential grooves include an inner shoulder circumferential groove located closest to the inner tread end when mounted on a vehicle, The five land portions include an inner shoulder land portion including the inner tread end, and an inner middle land portion adjacent to the inner shoulder land portion via the inner shoulder circumferential groove, The inner shoulder land portion is provided with a plurality of inner shoulder sipes that communicate with the inner shoulder circumferential groove, The inner middle land portion is provided with a plurality of inner middle sipes that completely traverse the inner middle land portion in the direction of the tire axis, Each of the aforementioned inner shoulder sipe and inner middle sipe includes a pair of sipe walls, Each of the aforementioned inner shoulder sipe and inner middle sipe includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other. The tire according to any one of claims 1 to 4, wherein the width of the main body portion of the inner shoulder sipe is greater than the width of the main body portion of the inner middle sipe.

6. The tire according to claim 5, wherein the inner shoulder sipe extends beyond the inner tread edge.

7. The four circumferential grooves include outer crown circumferential grooves and inner crown circumferential grooves arranged on both sides of the tire equator, The five land portions include a crown land portion divided between the outer crown circumferential groove and the inner crown circumferential groove, The crown land portion includes an outer region on the outer tread edge side of the tire equator and an inner region on the inner tread edge side of the tire equator, The tire according to any one of claims 1 to 6, wherein the width in the tire axial direction of the contact surface of the outer region is greater than the width in the tire axial direction of the contact surface of the inner region.

8. The tire according to claim 7, wherein the crown land portion is provided with a plurality of first crown sipes extending from the inner crown circumferential groove and interrupted within the contact surface of the crown land portion, and a plurality of second crown sipes extending from the outer crown circumferential groove and having closed ends within the contact surface of the crown land portion.

9. The four circumferential grooves include an outer crown circumferential groove adjacent to the inner tread end side of the outer middle land portion, The tire according to claim 1, wherein the outer middle sipe has an end that closes within the outer middle land portion without reaching the outer crown circumferential groove.

10. A tire having a tread portion in which the orientation of mounting to a vehicle is specified, The tread portion includes an outer tread end located on the outside of the vehicle when mounted on the vehicle, an inner tread end located on the inside of the vehicle when mounted on the vehicle, four circumferential grooves extending continuously in the circumferential direction of the tire between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves. The four circumferential grooves mentioned above include the outer shoulder circumferential groove located closest to the outermost tread edge when mounted on the vehicle. The five land portions include an outer shoulder land portion including the outer tread end, and an outer middle land portion adjacent to the outer shoulder land portion via the outer shoulder circumferential groove, The aforementioned outer shoulder land portion has the largest width in the tire axial direction of the contact surface among the five land portions. The outer shoulder land portion is provided with a plurality of outer shoulder sipes that communicate with the outer shoulder circumferential groove, The outer middle land portion is provided with a plurality of outer middle sipes that communicate with the outer shoulder circumferential groove, Each of the outer shoulder sipe and the outer middle sipe includes a pair of sipe walls, Each of the outer shoulder sipe and the outer middle sipe includes a main body portion in which the pair of sipe walls are arranged substantially parallel to each other. The width of the main body portion of the outer shoulder sipe is greater than the width of the main body portion of the outer middle sipe. The four circumferential grooves include the outer crown circumferential groove adjacent to the inner tread end side of the outer middle land portion, The outer middle sipe has an end that closes within the outer middle land portion without reaching the outer crown circumferential groove. The outer shoulder sipe and the outer middle sipe each have at least one of their sipe edges formed with a chamfered portion. The maximum depth of the chamfered portion of the outer middle sipe is greater than the maximum depth of the chamfered portion of the outer shoulder sipe. tire.

11. The outer middle land portion is provided with a plurality of interrupted middle sipes, The tire according to claim 9 or 10, wherein the interrupted middle sipe communicates with the outer crown circumferential groove and has an end that closes within the outer middle land portion without reaching the outer shoulder circumferential groove.

12. The tire according to any one of claims 9 to 11, wherein the outer middle land portion is provided with an outer middle longitudinal sipe that extends continuously in the circumferential direction of the tire.

Images