tire
By optimizing the groove structure of the tire tread, an effective drainage path is formed and snow performance is improved. This solves the problem that the existing tires suffer from reduced traction performance on dry roads when improving wet performance, and achieves a balanced improvement in traction performance on dry roads and wet and snow performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUMITOMO RUBBER INDUSTRIES LTD
- Filing Date
- 2021-11-30
- Publication Date
- 2026-07-31
AI Technical Summary
While existing pneumatic tires improve wet performance, their traction performance on dry roads is easily compromised.
Design a tire tread pattern comprising 4 circumferential grooves and 5 land sections, with multiple axial grooves and crown sipes, optimizing the width, depth, and angle of the grooves to form an effective drainage path and improve snow performance.
While maintaining traction performance on dry roads, it significantly improves performance on wet and snowy surfaces.
Smart Images
Figure CN114571914B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a tire. Background Technology
[0002] Patent Document 1 discloses a pneumatic tire having an asymmetrical tread pattern specified in the vehicle's mounting direction. The tread portion of the pneumatic tire has inner transverse grooves extending from a position closer to the vehicle's interior than the contact patch end to the tire equator. It is intended that the pneumatic tire drain a film of water between the land portion of the tread and the road surface to the interior of the vehicle through these inner transverse grooves.
[0003] [Existing Technical Documents]
[0004] Patent documents
[0005] [Patent Document 1] Japanese Patent Application Publication No. 2013-100020 Summary of the Invention
[0006] The problem that the invention aims to solve
[0007] In recent years, there has been a demand for tires capable of handling various road surfaces. The pneumatic tire in Patent Document 1 achieves high wet performance, but there is still room for improvement in terms of snow performance.
[0008] On the other hand, tires that have improved wet and snow performance also have the problem of easily damaged traction performance on dry roads.
[0009] This disclosure is made in view of the above-mentioned actual situation, and the main objective is to provide a tire that maintains traction performance on dry roads and improves wet and snow performance.
[0010] Solution for solving the problem
[0011] This disclosure relates to a tire having a tread portion designated in the vehicle mounting direction. The tread portion includes an outer tread end that becomes the outer side of the vehicle when mounted to the vehicle, an inner tread end that becomes the inner side of the vehicle when mounted to the vehicle, four circumferential grooves extending continuously in the tire circumferential direction between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves. The four circumferential grooves include an inner shoulder circumferential groove disposed closest to the inner tread end, an inner crown circumferential groove disposed between the inner shoulder circumferential groove and the tire equator, and an outer crown circumferential groove adjacent to the inner crown circumferential groove across the tire equator. The five land portions... The land portion includes an inner shoulder land portion containing the inner tread end, an inner central land portion between the inner shoulder circumferential groove and the inner crown circumferential groove, and a crown land portion between the inner crown circumferential groove and the outer crown circumferential groove. The tread portion is provided with at least a plurality of axial grooves extending from the inner tread end to the crown land portion and interrupted within the crown land portion. The crown land portion is provided with at least one crown sipe pattern extending from the inner crown circumferential groove or the outer crown circumferential groove to the tire axial direction and interrupted within the crown land portion. The crown sipe pattern traverses the center position of the crown land portion along the tire axial direction.
[0012] In the tire disclosed herein, preferably the axial groove includes a crown groove portion disposed on the land portion of the crown, and the crown sipe pattern includes a plurality of first crown sipe patterns extending from the inner crown circumferential groove, wherein the tire axial length of the first crown sipe pattern is less than the tire axial length of the crown groove portion.
[0013] In the tire disclosed herein, preferably the tread groove pattern includes a plurality of second tread groove patterns extending from the outer circumferential groove of the tread, wherein the axial length of the first tread groove pattern is greater than or equal to the axial length of the second tread groove pattern.
[0014] In the tires disclosed herein, it is preferable that the first tread groove pattern and the second tread groove pattern are alternately arranged in the tire circumferential direction.
[0015] In the tires disclosed herein, it is preferable that the total number of the second tread groove pattern is less than or equal to the total number of the first tread groove pattern.
[0016] In the tire disclosed herein, the axial groove preferably includes a crown groove portion disposed on the crown land portion, the crown groove portion including an outer portion with an opening of a width greater than 1.5 mm on the tread surface of the crown land portion and a sipe pattern portion extending radially along the tire from the bottom of the outer portion with a width of less than 1.5 mm.
[0017] In the tire disclosed herein, it is preferred that the depth of the outer portion is 2.5 mm or less.
[0018] In the tires disclosed herein, it is preferable that the circumferential pitch length of the plurality of axial grooves is less than the axial width of the inner shoulder land portion of the tire.
[0019] In the tire disclosed herein, the axial groove includes a central groove portion disposed on the central land portion, the central groove portion including a reinforcing rib (tie bar) with a partial bulge at the bottom.
[0020] In the tire disclosed herein, it is preferable that the inner central land portion is provided with a plurality of first central sipes extending axially from the inner shoulder circumferential groove and interrupted within the inner central land portion, and a plurality of second central sipes extending axially from the inner crown circumferential groove and interrupted within the inner central land portion, wherein the total number of the second central sipes is greater than the total number of the first central sipes.
[0021] Invention Effects
[0022] The tire disclosed herein, by employing the above-described configuration, can maintain traction performance on dry roads and exhibit excellent wet and snow performance. Attached Figure Description
[0023] Figure 1 This is a unfolded view of the tread area according to one embodiment of the present disclosure.
[0024] Figure 2 yes Figure 1 Enlarged view of the inner shoulder land area, inner central land area, and crown land area.
[0025] Figure 3 yes Figure 2 AA-line cross-section view.
[0026] Figure 4 yes Figure 2 BB line cross-section.
[0027] Figure 5 yes Figure 2 CC line cross-section.
[0028] Figure 6 yes Figure 2 DD line cross-section.
[0029] Figure 7 yes Figure 2 EE line cross-section.
[0030] Figure 8 yes Figure 1Enlarged view of the outer central land area and the outer shoulder land area.
[0031] Figure 9 This is an enlarged view of the inner central land portion of another embodiment of this disclosure.
[0032] Figure 10 yes Figure 9 FF line cross-section.
[0033] Figure 11 yes Figure 9 GG line cross-section diagram.
[0034] Figure 12 yes Figure 9 HH line cross-section diagram.
[0035] Figure 13 yes Figure 9 Sectional view along line II.
[0036] Marker description
[0037] 2nd pregnancy face
[0038] 3 Circumferential grooves
[0039] 4. Land Department
[0040] 5. Inner shoulder circumferential groove
[0041] 6. Inner circumferential groove of the tire crown
[0042] 7. Outer crown circumferential groove
[0043] 10. Inner shoulder of the tire, on the land side.
[0044] 11 Inner Central Land Section
[0045] 12. Land section of the tire crown
[0046] 15 Axial groove
[0047] 20 Tire crown sipes
[0048] To the outer tread end
[0049] Ti inner tread end Detailed Implementation
[0050] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. Figure 1 This is a unfolded view of the tread portion 2 of the tire 1 disclosed herein. (See diagram below.) Figure 1 As shown, the tire 1 of this embodiment is used as an all-season pneumatic tire for passenger cars, including those used for driving on snowy roads. However, the tire 1 of this disclosure is not limited to this method.
[0051] The tire 1 disclosed herein has a tread portion 2 whose mounting direction on a vehicle is specified. The mounting direction on a vehicle is indicated by text or markings, for example, on the tire sidewall (illustrations omitted). Furthermore, the tread portion 2 is composed of, for example, an asymmetrical pattern (meaning the tread pattern is not linearly symmetrical with respect to the tire equator C).
[0052] The tread portion 2 includes an outer tread end To located on the outside of the vehicle when mounted on the vehicle, and an inner tread end Ti located on the inside of the vehicle when mounted on the vehicle. The outer tread end To and the inner tread end Ti are respectively the contact points closest to the outermost axial direction of the tire when the tire 1 is loaded with a normal load and contacts the flat ground at a camber angle of 0° in a normal state.
[0053] The term "standard condition" refers to the condition of a pneumatic tire of various specifications, where the tire is assembled on a normal rim, inflated to the standard internal pressure, and without load. For tires without specified specifications or non-pneumatic tires, the term "standard condition" means the standard operating condition corresponding to the tire's intended use, without load. In this specification, unless otherwise specified, the dimensions of all parts of the tire are values measured under the standard condition.
[0054] "Standard rim" refers to the rim specified for each tire within a specification system that includes the tire's base specifications. For example, it is "standard rim" in JATMA, "Design Rim" in TRA, and "Measuring Rim" in ETRTO.
[0055] "Standard tire pressure" refers to the air pressure specified for each tire in the specification system that includes the tire's specifications. In JATMA, it is the "maximum air pressure," in TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATIONPRESSURES," and in ETRTO, it is "INFLATIONPRESSURE."
[0056] "Regular load" for various specifications of pneumatic tires refers to the load specified for each tire within the specification system that the tire is based on. In JATMA, it is "maximum load capacity"; in TRA, it is the maximum value recorded in the table "TIRE LOADLIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in ETRTO, it is "LOADCAPACITY". Furthermore, for tires without specified specifications or non-pneumatic tires, "regular load" refers to the load acting on a single tire under its standard mounting condition. The "standard mounting condition" means that the tire is mounted on a standard vehicle corresponding to its intended use, and the vehicle is stationary on a level road surface in a drivable condition.
[0057] The tread portion 2 includes four circumferential grooves 3 that extend continuously along the tire circumference between the outer tread end To and the inner tread end Ti, and five land portions 4 divided by the four circumferential grooves 3.
[0058] The four circumferential grooves 3 include an inner shoulder circumferential groove 5 disposed on the side closest to the inner tread end Ti, an inner crown circumferential groove 6 disposed between the inner shoulder circumferential groove 5 and the tire equator C, and an outer crown circumferential groove 7 adjacent to the inner crown circumferential groove 6 across the tire equator C. Furthermore, in this embodiment, an outer shoulder circumferential groove 8 is provided between the outer tread end To and the outer crown circumferential groove 7. The outer shoulder circumferential groove 8 is disposed on the side closest to the outer tread end To.
[0059] The circumferential groove 3 can be in various forms, such as a groove extending in a straight line along the tire circumference or a groove extending in a serrated shape.
[0060] The tire axial distance L1 from the center line of the outer circumferential groove 7 or the inner circumferential groove 6 to the tire equator C is, for example, 5% to 15% of the tread width TW. The tire axial distance L2 from the center line of the outer shoulder circumferential groove 8 or the inner shoulder circumferential groove 5 to the tire equator C is, for example, 25% to 35% of the tread width TW. Furthermore, the tread width TW is the tire axial distance from the outer tread end To to the inner tread end Ti in the normal state.
[0061] The groove width W1 of the circumferential groove 3 is preferably at least 3 mm. In a more preferred embodiment, the groove width W1 of the circumferential groove 3 is 3.0% to 7.0% of the tread width TW.
[0062] The five land portions 4 include at least an inner shoulder land portion 10 containing the inner tread end Ti, an inner central land portion 11 between the inner shoulder circumferential groove 5 and the inner crown circumferential groove 6, and a crown land portion 12 between the inner crown circumferential groove 6 and the outer crown circumferential groove 7. In this embodiment, the five land portions 4 also include an outer shoulder land portion 14 containing the outer tread end To, and an outer central land portion 13 between the outer shoulder circumferential groove 8 and the outer crown circumferential groove 7.
[0063] Figure 2 Enlarged views of the inner shoulder land portion 10, the inner central land portion 11, and the crown land portion 12 are shown. Figure 2 As shown, the tread portion 2 is provided with a plurality of axial grooves 15. The axial grooves 15 extend at least from the inner tread end Ti toward the axially inner side of the tire. The axial grooves 15 pass through the inner shoulder land portion 10, the inner shoulder circumferential groove 5, the inner central land portion 11, and the inner crown circumferential groove 6, respectively, and extend to the crown land portion 12, and are interrupted within the crown land portion 12. Through the axial grooves 15, a drainage path is formed extending from the crown land portion 12 to the inner tread end Ti.
[0064] The land portion 12 of the tread is provided with at least one tread groove pattern 20. The tread groove pattern 20 extends axially from the inner circumferential groove 6 or the outer circumferential groove 7 of the tread and is interrupted within the land portion 12 of the tread.
[0065] In this specification, "groove pattern" refers to a cutting element with a narrow width, wherein the width between two opposing inner walls is 1.5 mm or less. The width of the groove pattern is preferably 0.3 to 1.0 mm. In this embodiment, each groove pattern opens within the specified width range in the tread surface of the land portion. The bottom of the groove pattern can be connected to, for example, a flamed bottom with a width exceeding 1.5 mm.
[0066] In this disclosure, the tread grooves 20 traverse the axial center of the tire's land portion 12. By employing the above-described configuration, traction performance on dry roads and excellent wet and snow performance can be maintained. The reason for this is presumably due to the following mechanism.
[0067] The aforementioned axial groove 15 provides high drainage, thus improving wet performance. Furthermore, the axial groove 15 forms horizontal snow columns during snow driving, providing significant snow column shear force and improving snow performance. Additionally, the tread groove pattern 20 is interrupted within the tread land portion 12, thereby maintaining the rigidity of the tread land portion 12 and thus maintaining traction performance on dry roads. Furthermore, the tread groove pattern 20, which passes through the center of the tread land portion 12, provides a large marginal effect, improving both wet and snow performance. It is presumed that the tire 1 of this disclosure, through this mechanism, can maintain traction performance on dry roads and exhibit excellent wet and snow performance.
[0068] The embodiments of this disclosure will be further described in detail below. Furthermore, the configurations described below illustrate specific aspects of this embodiment. Therefore, it is evident that the above-described effects can be achieved even without the configurations described below. Moreover, even if only one of the configurations described below is applied individually, the tire of this disclosure possessing the above-described features can be expected to exhibit improved performance corresponding to each configuration. Furthermore, when several combinations of the configurations described below are applied, performance improvements corresponding to the combination of configurations can be expected.
[0069] The axial groove 15 passes through the inner shoulder land portion 10 at a position, for example, closer to the axial outer side of the tire than the inner tread end Ti. Thus, the inner shoulder land portion 10 is divided into multiple blocks. This axial groove 15 provides excellent drainage performance. Furthermore, the axial groove 15 includes a shoulder groove portion 16 disposed on the inner shoulder land portion 10, a central groove portion 17 disposed on the inner central land portion 11, and a crown groove portion 18 disposed on the crown land portion 12. The axial groove 15 forms a substantially single drainage path through the shoulder groove portion 16, the central groove portion 17, and the crown groove portion 18. Therefore, the shoulder groove portion 16, extending along its length to an imaginary region on the tire equator C side, coincides with the end of the central groove portion 17 on the inner tread end Ti side. Similarly, the central groove portion 17, extending along its length to an imaginary region on the tire equator C side, coincides with the end of the crown groove portion 18 on the inner tread end Ti side.
[0070] The imaginary area of the shoulder groove 16 preferably overlaps with the groove width of the end of the central groove 17 by more than 50%, and more preferably by more than 80%. Similarly, the imaginary area of the central groove 17 preferably overlaps with the groove width of the end of the crown groove 18 by more than 50%, and more preferably by more than 80%. As a more preferred embodiment, in this embodiment, the imaginary area of the shoulder groove 16 overlaps with the groove width of the end of the central groove 17 by 100%, and the imaginary area of the central groove 17 overlaps with the groove width of the end of the crown groove 18 by 100%. This effectively improves wetland performance.
[0071] The groove width of the axial groove 15 is preferably towards the outer tread end To ( Figure 1 (As shown in the diagram, the same applies below) gradually decreases in size. In other words, the width of the central groove 17 is smaller than the width of the shoulder groove 16, and the width of the crown groove 18 is smaller than the width of the central groove 17. The width of the shoulder groove 16 is, for example, 4.4 to 5.0 mm. The width of the central groove 17 is, for example, 3.3 to 4.4 mm. The width of the crown groove 18 is, for example, 3.3 mm or less. Such axial grooves 15 can effectively improve handling stability on dry roads (hereinafter sometimes referred to as "handling stability") as well as wet and snow performance.
[0072] The axial groove 15 is inclined relative to the tire axial direction, for example. The angle of the axial groove 15 relative to the tire axial direction is, for example, 5 to 25°. More preferably, in this embodiment, the angle of the axial groove 15 relative to the tire axial direction gradually increases towards the outer tread end To side. Such an axial groove 15 can provide snow column shear force to the tire axial direction as well when driving on snow.
[0073] The length P1 of one pitch in the tire circumferential direction of the plurality of axial grooves 15 is preferably less than the tire axial width W1 of the inner shoulder land portion 10. Specifically, the length P1 of one pitch is 70% to 95% of the width W2 of the inner shoulder land portion 10. As a further preferred embodiment, the length P1 of one pitch of the axial groove 15 is less than the tire axial width W3 of the inner central land portion 11 and also less than the tire axial width W4 of the crown land portion 12. Such an arrangement of axial grooves 15 effectively improves wet and snow performance. In addition, in this specification, the length of one pitch means the distance between the center lines of two adjacent grooves.
[0074] The crown groove 18, for example, traverses the center of the tire axial direction of the crown land portion 12. The axial length L3 of the crown groove 18 is, for example, 60% to 90% of the axial width W4 of the crown land portion 12. This allows for a well-balanced improvement in traction performance on dry roads, as well as wet and snow performance.
[0075] Figure 3 Show Figure 2 The AA-line cross-section diagram. (See attached diagram.) Figure 3As shown, the tread groove 18 includes an outer portion 23 with an opening of greater than 1.5 mm on the tread surface of the tread land portion 12, and a sipe pattern 24 extending radially from the bottom of the outer portion 23 with a width of less than 1.5 mm. The depth d1 of the outer portion 23 is, for example, less than 2.5 mm, preferably, for example, 1.0 to 2.0 mm. Furthermore, the depth d1 of the outer portion 23 is 15% to 30% of the total depth dt of the tread groove 18. Such a tread groove 18 can maintain the rigidity of the tread land portion 12 and, when driving on wet surfaces, guides the internal horizontal slip to the central groove 17 (shown in the figure) as the contact pressure changes. Figure 2 )side.
[0076] Figure 4 Show Figure 2 The BB line cross-section diagram. (See attached diagram.) Figure 4 As shown, the central groove 17 preferably includes a reinforcing rib 25 with a partial bulge at the bottom. In this embodiment, the reinforcing rib 25 is provided in the central region when the central groove 17 is divided into three equal parts along its length in a top view of the tread. Such a reinforcing rib 25 serves to maintain the rigidity of the inner central land portion 11 and improve traction performance on dry roads.
[0077] To ensure wet performance and achieve the aforementioned effects, the axial length L9 of the reinforcing rib 25 is preferably the width W3 of the tire axial direction of the inner central land portion 11 (shown in...). Figure 2 The length of the reinforcing rib 25 is 25% to 40% of the tire's radial direction. Furthermore, when the length of the reinforcing rib 25 varies along the tire's radial direction, the length is the length measured at the center position of the tire's radial direction. Additionally, the minimum depth d3 of the portion where the reinforcing rib 25 is provided is, for example, 30% to 50% of the maximum depth d2 of the central groove 17.
[0078] Figure 5 As shown in the cross-section of stiffener 25, the diagram shows... Figure 2 The CC-line cross-section. (See diagram below.) Figure 5 As shown, the reinforcing rib 25 is preferably provided with a groove pattern 26 at the bottom of the groove, the surface of which is open. The groove pattern 26 is provided, for example, so that it completely passes through the reinforcing rib 25 along the length of the central groove 17. Such a groove pattern 26 at the bottom of the groove serves to maintain the drainage of the central groove 17.
[0079] Figure 6 Show Figure 2 The DD line cross-section diagram. (See example) Figure 6 As shown, the shoulder groove 16, along the path between the contact surface 10s of the inner shoulder land portion 10 and the bottom of the groove, includes a minimum portion 27 where the groove width of the shoulder groove 16 becomes extremely small. This mitigates the decrease in wet performance associated with wear on the tread surface 2.
[0080] The maximum depth d4 of the shoulder groove 16 is, for example, 70% to 90% of the maximum depth of the inner shoulder circumferential groove 5. Furthermore, the depth d5 from the contact patch 10s to the miniature portion 27 is, for example, less than 50% of the maximum depth d4 of the shoulder groove 16. The depth d5 of the miniature portion 27 is preferably 10% to 40% of the aforementioned depth d1. Thus, during the stage when the wear of the tread 2 is moderate, the miniature portion 27 is exposed to the contact patch 10s, which can suppress the subsequent decrease in wet performance accompanying the wear of the tread 2.
[0081] The groove width W6 of the miniature portion 27 is, for example, 30% to 60% of the groove width W5 in the contact surface 10s of the tire shoulder groove portion 16, preferably 40% to 50%. Such a miniature portion 27 serves to maintain smoothness in both dry and wet performance.
[0082] In the region from the contact patch 10s to the minimum portion 27, the angle θ1 of the groove wall of the shoulder groove 16 relative to the tire normal is 40 to 60°. Therefore, when the tire is first used, the groove wall, which is closer to the radial outer edge of the tire than the minimum portion 27, properly contacts the ground as the contact pressure increases. In other words, the groove wall, which is closer to the radial outer edge of the tire than the minimum portion 27, can function as a chamfered portion, thereby potentially improving traction and braking performance.
[0083] The shoulder groove 16 includes a main body 28 that is closer to the radially inner side of the tire than the minimum portion 27. The maximum groove width W7 of the main body 28 is the same as or smaller than the groove width W5 in the contact patch 10s of the shoulder groove 16. The maximum groove width W7 of the main body 28 is, for example, 50% to 100% of the groove width W5 in the contact patch 10s of the shoulder groove 16, preferably 70% to 100%. As a result, sufficient wet performance can be achieved when the tread 2 is worn to the extent that it is exposed near the maximum groove width W7.
[0084] The main body 28 includes a region where the groove width expands radially inward toward the tire. The angle θ2 of the groove wall relative to the tire normal in this region is smaller than the angle θ1, for example, 15 to 25°.
[0085] like Figure 2As shown, the tread groove pattern 20 includes a plurality of first tread groove patterns 21 and a plurality of second tread groove patterns 22. The first tread groove pattern 21 extends axially from the inner circumferential groove 6 of the tread and is interrupted within the tread land portion 12. The second tread groove pattern 22 extends axially from the outer circumferential groove 7 of the tread and is interrupted within the tread land portion 12. The first tread groove patterns 21 and the second tread groove patterns 22 are alternately arranged, for example, in the tire circumferential direction. More preferably, in this embodiment, one first tread groove pattern 21 and one second tread groove pattern 22 are respectively provided between two tread groove portions 18. However, this disclosure is not limited to this arrangement.
[0086] In the entire crown land portion 12, the total number of the second crown sipes 22 is, for example, less than or equal to the total number of the first crown sipes 21. Preferably, in this embodiment, the total number of the first crown sipes 21 is the same as the total number of the second crown sipes. This suppresses uneven wear on the crown land portion 12.
[0087] To achieve a good balance between improving handling stability on dry roads and wet performance, the axial length L4 of the tread groove pattern 20 is less than the axial length L3 of the tread groove portion 18. Specifically, the length L4 of the tread groove pattern 20 is 55% to 80% of the axial width W4 of the tread land portion 12.
[0088] The axial length of the first tread groove 21 is less than the axial length L3 of the tread groove portion 18. Furthermore, it is preferable that the axial length of the first tread groove 21 is greater than or equal to the axial length of the second tread groove 22.
[0089] The first crown sipe 21 and the second crown sipe 22 are inclined, for example, in the same direction as the crown groove 18, and in a preferred embodiment, their angle difference is 5° or less. The angles of the first crown sipe 21 and the second crown sipe 22 relative to the tire axial direction are, for example, 15 to 25°. More preferably, in this embodiment, the first crown sipe 21, the second crown sipe 22, and the crown groove 18 extend parallel to each other. This suppresses uneven wear on the crown land portion 12.
[0090] The inner central land area 11 is provided with a plurality of first central sipes 31 and a plurality of second central sipes 32. The first central sipes 31 extend axially from the inner shoulder towards the groove 5 along the tire axis and are interrupted within the inner central land area 11. The second central sipes 32 extend axially from the inner crown towards the groove 6 along the tire axis and are interrupted within the inner central land area 11. Such first central sipes 31 and second central sipes 32 can maintain the rigidity of the inner central land area 11 and exert a boundary effect.
[0091] In a preferred embodiment, the total number of the second central sipes 32 is greater than the total number of the first central sipes 31. Specifically, the total number of the second central sipes 32 is 1.5 to 2.5 times the total number of the first central sipes 31. As a result, the end of the central groove 17 on the tire equator side C is more prone to deformation than the end on the inner tread side Ti. Therefore, the central groove 17 easily deforms during wet driving to guide internal water to the inner tread side Ti, further improving wet performance.
[0092] The axial length L5 of the first central sipe 31 is, for example, 40% to 60% of the axial width W3 of the inner central land portion 11. The same applies to the second central sipe 32. This facilitates the achievement of the aforementioned effects.
[0093] The first central sipe 31 and the second central sipe 32 are inclined, for example, in the same direction as the central groove 17, and in a preferred embodiment, their angle difference is 5° or less. The angles of the first central sipe 31 and the second central sipe 32 relative to the tire axial direction are, for example, 10 to 20°. More preferably, in this embodiment, the first central sipe 31, the second central sipe 32, and the central groove 17 extend parallel to each other. This suppresses uneven wear on the inner central land area 11.
[0094] In the inner shoulder land portion 10, a plurality of inner shoulder sipes 33 are provided. The inner shoulder sipes 33 extend from the inner shoulder circumferential groove 5 along the outer side of the tire axial direction and at least cross the inner tread end Ti.
[0095] The inner shoulder sipes 33 are inclined in the same direction as the shoulder groove 16, and in a preferred embodiment, their angle difference is 5° or less. The angle of the inner shoulder sipes 33 relative to the tire axial direction is, for example, 5 to 15°. More preferably, in this embodiment, the inner shoulder sipes 33 and the shoulder groove 16 extend parallel to each other. This suppresses uneven wear on the inner shoulder land portion 10.
[0096] Figure 7 Show Figure 2 EE line cross-section diagram. (See diagram below.) Figure 7 As shown, the inner shoulder sipes 33 extends radially from the contact surface 10s of the inner shoulder land portion 10 with a width W8 of less than 1.5 mm. Furthermore, the inner side of the inner shoulder sipes 33 in the tire axial direction communicates with an inner groove 34 having a groove width larger than the width of the inner shoulder sipes 33. The maximum width W9 of the inner groove 34 is 2.0 to 4.0 times the width W8 of the inner shoulder sipes 33. This inner groove 34 helps maintain wet performance even when the tread 2 is worn.
[0097] Figure 8 An enlarged view of the outer central land portion 13 and the outer shoulder land portion 14 is shown. Figure 8 As shown, the outer central land portion 13 is provided with a first central interruption groove 36, a second central interruption groove 37, and a decorative knife groove pattern 38.
[0098] The first central break groove 36 extends axially from the outer circumferential groove 7 of the tire crown and terminates within the outer central land portion 13. The first central break groove 36 terminates, for example, without passing through the axial center of the outer central land portion 13. The axial length L6 of the first central break groove 36 is, for example, 15% to 25% of the axial width W10 of the outer central land portion 13. This first central break groove 36 provides a good balance, improving handling stability and wet performance.
[0099] The first central interruption groove 36 is inclined, for example, in the same direction as the axial groove 15 relative to the tire axial direction. The angle of the first central interruption groove 36 relative to the tire axial direction is preferably greater than the maximum angle of the axial groove 15 relative to the tire axial direction. The angle of the first central interruption groove 36 relative to the tire axial direction is, for example, 70 to 80°.
[0100] From the same perspective, the second central interruption groove 37 extends axially from the outer shoulder towards the groove 8 and is interrupted within the outer central land portion 13. The second central interruption groove 37 is interrupted, for example, without passing through the axial center of the outer central land portion 13. The axial length L7 of the second central interruption groove 37 is, for example, 30% to 45% of the axial width W10 of the outer central land portion 13.
[0101] The second central interruption groove 37 is inclined, for example, in the opposite direction to the axial groove 15 relative to the tire axial direction. The angle of the second central interruption groove 37 relative to the tire axial direction is smaller than the angle of the first central interruption groove 36 relative to the tire axial direction. The angle of the second central interruption groove 37 relative to the tire axial direction is, for example, 5 to 15°.
[0102] The decorative sipes 38 have an opening width of less than 1.5 mm and a depth of 0.5 to 1.5 mm on the contact patch of the land section. These decorative sipes 38 provide a high boundary effect when the tire is first used, improving snow performance.
[0103] The decorative sipe 38 is interrupted at both ends within the outer central land portion 13. Furthermore, the decorative sipe 38 is inclined in the same direction relative to the tire axial direction as the first central interrupted groove 36. The angle of the decorative sipe 38 relative to the tire axial direction is, for example, 60 to 80°.
[0104] The decorative sipes 38, for example, pass through the axial center of the tire's outer central land portion 13. The tire circumferential length L8 of the decorative sipes 38 is, for example, 1.3 to 2.0 times the tire circumferential pitch length P2 of the second central interrupted groove 37. Such decorative sipes 38 can generate large axial friction on snowy roads.
[0105] In the outer shoulder land portion 14, a plurality of outer shoulder transverse grooves 41 and a plurality of outer shoulder sipes 42 are provided. The outer shoulder transverse grooves 41 have a connection with the shoulder groove portion 16 (shown in the figure). Figure 2 The outer shoulder lateral groove 41 has essentially the same structure as the shoulder groove 16 described above. Furthermore, the outer shoulder sipe 42 has the same structure as the inner shoulder sipe 33 (shown in…). Figure 2 The configuration is essentially the same. Therefore, the outer shoulder sipe 42 can utilize the configuration of the inner shoulder sipe 33 described above.
[0106] Figure 9 An enlarged view of the inner central land portion 11 according to another embodiment of this disclosure is shown. In this embodiment, the configuration other than the inner central land portion 11 can be applied to the configuration already described. Figure 9 In this document, elements already described use the same reference numerals as those described above, and the above-described structure applies to all matters not specifically stated above. Furthermore, in... Figure 9 In the central land portion 11, dots are applied to the opening portions of the central groove 17, the first central groove pattern 31, and the second central groove pattern 32. Furthermore, in... Figure 9 The outline of the interior of the central groove 17, which can be confirmed from the top view of the tread, is shown.
[0107] Figure 10 It shows Figure 9 The FF line profile. For example... Figure 10As shown, the central groove 17 in this embodiment includes a first portion 46 and a second portion 47 provided with reinforcing ribs 25. The depth d7 of the first portion 46 is, for example, 65% to 80% of the depth d6 of the inner tread circumferential groove 6. The depth d8 of the second portion 47 (the depth from the tread surface of the land portion to the surface of the reinforcing rib 25) is, for example, 55% to 75% of the depth d7 of the first portion 46. The central groove 17 with such reinforcing ribs 25 serves to maintain the rigidity of the inner central land portion 11, thereby improving traction performance on dry roads.
[0108] The boundary 48 between part 1 46 and part 2 47 is preferably positioned in, for example, the central region where the central groove 17 is divided into three equal parts along the tire axis. This allows for a balanced improvement in traction performance on dry roads, wet performance, and snow performance. Furthermore, as... Figure 9 As shown in the top view of the tread, the boundary 48 of this embodiment extends at an angle relative to the orthogonal direction of the central groove 17. This can suppress uneven wear near the boundary 48 of the inner central land portion 11.
[0109] Figure 11 Show Figure 9 The GG line profile. Figure 12 The middle shows Figure 9 The HH profile. For example... Figure 11 and Figure 12 As shown, in this embodiment, chamfered portions 50 are provided on the first portion 46 and the second portion 47 of the central groove 17. The chamfered portion 50 includes an inclined surface 51 between the tread surface of the land portion and the groove wall body of the central groove 17. The angle θ3 of the inclined surface 51 relative to the tire normal is, for example, 40 to 60°. Such chamfered portions 50 serve to suppress uneven wear of the inner central land portion 11.
[0110] like Figure 12 As shown, section 2 47 is provided with a groove bottom pattern 26 that opens on the surface of the reinforcing rib 25. The groove bottom pattern 26 is configured, for example, to completely span the reinforcing rib 25 along the length of the central groove 17. Such a groove bottom pattern 26 serves to maintain the drainage of the central groove 17.
[0111] In Part 2, Section 47, the total depth d9 from the tread surface of the land section to the bottom of the groove pattern 26 is preferably the depth d7 of Part 1, Section 46 (shown in...). Figure 10 The total depth d9 is 80% to 120% of the depth d7 of the first part 46. In a more preferred embodiment, the total depth d9 is equal to the depth d7 of the first part 46. As a result, the difference in rigidity between the periphery of the first part 46 and the periphery of the second part 47 is small, and the uneven wear of the inner central land portion 11 is suppressed.
[0112] like Figure 9As shown, in this embodiment, the second part 47 is disposed in the central groove 17 closer to the inner shoulder circumferential groove 5 than the first part 46, and is alternately disposed in the central groove 17 closer to the inner crown circumferential groove 6 than the first part 46 in the tire circumferential direction. As a result, the uneven wear of the inner central groove 11 is further suppressed.
[0113] In this embodiment, a first central groove pattern 31 and a second central groove pattern 32 are provided between each of the two central groove portions 17. However, it is not limited to this method.
[0114] exist Figure 13 The middle shows Figure 9 The cross-sectional view along line II. (See figure) Figure 13 As shown, the first central sipe 31 and the second central sipe 32 of this embodiment may include a chamfered portion 55. The chamfered portion 55 includes an inclined surface 56 between the tread surface of the land portion and the inner wall of the sipe extending radially along the tire. The angle θ4 of the inclined surface 56 relative to the tire normal is, for example, 40 to 60°. Such a chamfered portion 55 serves to suppress uneven wear of the inner central land portion 11.
[0115] like Figure 9 As shown, the inclined surfaces 56 of the first central sipe 31 and the second central sipe 32 preferably gradually decrease in width towards the interrupted end 57 of the sipe 32. This results in a more uniform ground pressure acting on the inner central land portion 11, improving traction performance on dry roads.
[0116] The tire of one embodiment of the present disclosure has been described in detail above, but the present disclosure is not limited to the specific embodiment described above, and various modifications can be made to implement it.
[0117] Example
[0118] Based on the specifications in Table 1, a product with... Figure 1 The tire has a pattern size of 275 / 40ZR20. As a comparative example, a tire was manufactured in which the first and second tread groove patterns do not cross the axial center of the tread land portion. In addition to the above, the comparative example tire has the same characteristics as... Figure 1 The tires shown are essentially identical in structure. Traction performance on dry roads, wet performance, and snow performance were tested on each test tire. Common specifications and test methods for all test tires are as follows.
[0119] Wheel rim installation: 20×9.5J
[0120] Tire pressure: 250 kPa for all wheels
[0121] Test vehicle: 3500cc engine, rear-wheel drive
[0122] Installation location: All wheels
[0123] Traction performance on dry surfaces
[0124] The traction performance of the test vehicles on dry roads was evaluated by the driver's senses. The results were scored with the traction performance of the comparative examples set at 100; the higher the score, the better the dry or wet performance.
[0125] <Wetland performance>
[0126] The wet performance of the test vehicles on wet roads was evaluated by the drivers using their senses. The results were scored out of 100 for the wet performance of the comparative examples, with higher scores indicating better wet performance.
[0127] Snow performance
[0128] The snow performance of the test vehicles was evaluated by the drivers using their senses. The results were scored out of 100 for the snow performance of the comparative examples; a higher score indicated better snow performance. The test results are shown in Table 1.
[0129] Table 1
[0130]
[0131] As shown in Table 1, the tires of the embodiments maintain traction performance of 98-102 points on dry roads, while exhibiting excellent performance in wet conditions (104-108 points) and snow conditions (104-109 points). That is, it can be confirmed that the tires of this disclosure maintain traction performance on dry roads and demonstrate excellent wet and snow performance.
[0132] [Postscript]
[0133] This disclosure includes the following methods.
[0134] [This disclosure 1]
[0135] A tire having a tread portion designated in the mounting direction toward the vehicle, characterized in that,
[0136] The tread portion includes an outer tread end that becomes the outer side of the vehicle when installed on the vehicle, an inner tread end that becomes the inner side of the vehicle when installed on the vehicle, four circumferential grooves that extend continuously along the tire circumference between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves.
[0137] The four circumferential grooves include an inner shoulder circumferential groove located closest to the inner tread end, an inner crown circumferential groove located between the inner shoulder circumferential groove and the tire equator, and an outer crown circumferential groove adjacent to the inner crown circumferential groove across the tire equator.
[0138] The five land portions include an inner shoulder land portion containing the inner tread end, an inner central land portion between the inner shoulder circumferential groove and the inner crown circumferential groove, and a crown land portion between the inner crown circumferential groove and the outer crown circumferential groove.
[0139] The tread portion is provided with at least a plurality of axial grooves extending from the inner tread end to the crown land portion and interrupted within the crown land portion.
[0140] The land portion of the tread is provided with at least one tread groove pattern that extends axially from the inner circumferential groove of the tread or the outer circumferential groove of the tread and is interrupted within the land portion of the tread.
[0141] The tread grooves cross the center of the tire's axial direction on the land portion of the tread.
[0142] [This disclosure 2]
[0143] The tire according to this disclosure 1 is characterized in that,
[0144] The axial groove includes a crown groove portion disposed on the land portion of the crown.
[0145] The tread groove pattern includes a plurality of first tread groove patterns extending from the inner circumferential groove of the tread.
[0146] The axial length of the first tread groove pattern is less than the axial length of the tread groove portion.
[0147] [This disclosure 3]
[0148] The tire according to this disclosure 2 is characterized in that,
[0149] The tread groove pattern includes a plurality of second tread groove patterns extending from the outer circumferential groove of the tread.
[0150] The axial length of the first tread groove pattern is greater than or equal to the axial length of the second tread groove pattern.
[0151] [This disclosure 4]
[0152] The tire according to this disclosure 3 is characterized in that,
[0153] The first and second tread groove patterns are alternately arranged in the circumferential direction of the tire.
[0154] [This disclosure 5]
[0155] The tire according to disclosure 3 or 4 is characterized in that,
[0156] The total number of the second tire crown sipes is less than the total number of the first tire crown sipes.
[0157] [This disclosure 6]
[0158] The tire according to any one of 1 to 5 of this disclosure is characterized in that,
[0159] The axial groove includes a crown groove portion disposed on the land portion of the crown.
[0160] The tread groove includes an outer portion with an opening greater than 1.5 mm on the tread surface of the tread land portion and a sipe pattern extending radially from the bottom of the outer portion with a width of less than 1.5 mm.
[0161] [This disclosure 7]
[0162] The tire according to this disclosure 6 is characterized in that,
[0163] The depth of the outer portion is less than 2.5 mm.
[0164] [This disclosure is 8]
[0165] The tire according to any one of 1 to 7 of this disclosure is characterized in that,
[0166] The length of one pitch in the tire circumferential direction of the plurality of axial grooves is less than the width of the tire axial direction of the inner shoulder land portion.
[0167] [This disclosure is number 9]
[0168] The tire according to any one of 1 to 8 of this disclosure is characterized in that,
[0169] The axial groove includes a central groove portion disposed on the inner central land portion.
[0170] The central groove includes reinforcing ribs with a localized raised bottom.
[0171] [This disclosure is number 10]
[0172] The tire according to any one of 1 to 9 of this disclosure is characterized in that,
[0173] The inner central land portion is provided with a plurality of first central sipes extending axially from the inner shoulder groove and interrupted within the inner central land portion, and a plurality of second central sipes extending axially from the inner crown groove and interrupted within the inner central land portion.
[0174] The total number of patterns in the second central groove is greater than the total number of patterns in the first central groove.
Claims
1. A tire having a tread portion designated in the mounting direction toward the vehicle, characterized in that, The tread portion includes an outer tread end that becomes the outer side of the vehicle when installed on the vehicle, an inner tread end that becomes the inner side of the vehicle when installed on the vehicle, four circumferential grooves that extend continuously along the tire circumference between the outer tread end and the inner tread end, and five land portions divided by the four circumferential grooves. The four circumferential grooves include an inner shoulder circumferential groove located closest to the inner tread end, an inner crown circumferential groove located between the inner shoulder circumferential groove and the tire equator, and an outer crown circumferential groove adjacent to the inner crown circumferential groove across the tire equator. The five land portions include an inner shoulder land portion containing the inner tread end, an inner central land portion between the inner shoulder circumferential groove and the inner crown circumferential groove, and a crown land portion between the inner crown circumferential groove and the outer crown circumferential groove. The tread portion is provided with at least a plurality of axial grooves extending from the inner tread end to the crown land portion and interrupted within the crown land portion. The land portion of the tread is provided with at least one tread groove pattern that extends axially from the inner circumferential groove of the tread or the outer circumferential groove of the tread and is interrupted within the land portion of the tread. The tread grooves extend across the center of the tire's axial direction on the land portion of the tread. The length of one pitch in the tire circumferential direction of the plurality of axial grooves is less than the tire axial width of the inner shoulder land portion, and the length of one pitch is 70% to 95% of the width of the inner shoulder land portion. The length of one pitch of the axial groove is less than the tire axial width of the inner central land portion and also less than the tire axial width of the crown land portion.
2. The tire according to claim 1, characterized in that, The axial groove includes a crown groove portion disposed on the land portion of the crown. The tread groove pattern includes a plurality of first tread groove patterns extending from the inner circumferential groove of the tread. The axial length of the first tread groove pattern is less than the axial length of the tread groove portion.
3. The tire according to claim 2, characterized in that, The tread groove pattern includes a plurality of second tread groove patterns extending from the outer circumferential groove of the tread. The axial length of the first tread groove pattern is greater than or equal to the axial length of the second tread groove pattern.
4. The tire according to claim 3, characterized in that, The first and second tread groove patterns are alternately arranged in the circumferential direction of the tire.
5. The tire according to claim 3 or 4, characterized in that, The total number of the second tire crown sipes is less than the total number of the first tire crown sipes.
6. The tire according to any one of claims 1 to 4, characterized in that, The axial groove includes a crown groove portion disposed on the land portion of the crown. The tread groove includes an outer portion with an opening greater than 1.5 mm on the tread surface of the tread land portion and a sipe pattern extending radially from the bottom of the outer portion with a width of less than 1.5 mm.
7. The tire according to claim 6, characterized in that, The depth of the outer portion is less than 2.5 mm.
8. The tire according to any one of claims 1 to 4, characterized in that, The axial groove includes a central groove portion disposed on the inner central land portion. The central groove includes reinforcing ribs with a localized raised bottom.
9. The tire according to any one of claims 1 to 4, characterized in that, The inner central land portion is provided with a plurality of first central sipes extending axially from the inner shoulder groove and interrupted within the inner central land portion, and a plurality of second central sipes extending axially from the inner crown groove and interrupted within the inner central land portion. The total number of patterns in the second central groove is greater than the total number of patterns in the first central groove.