tire

Abstract

To improve noise performance.SOLUTION: Provided is a tire 1 having a tread part 2. The tread part 2 includes a plurality of circumferential grooves 3 and a plurality of land parts 4 divided by the circumferential grooves 3. A plurality of lateral groove-shaped elements 7 and 8 inclined with respect to a tire axial direction and a tire circumferential direction are formed on the plurality of land parts 4. The lateral groove-shaped elements 7 and 8, having a first end on a first side in the tire circumferential direction and a second end on a second side in the tire circumferential direction, extend linearly from the first end to the second end. The plurality of lateral groove-shaped elements 7 and 8 are arranged according to a first alignment over one circumference in the tire circumferential direction. In the first alignment, for each of all pairs of the adjacent lateral groove-shaped elements 7 and 8 in the tire circumferential direction, one first end of the one of the lateral groove-shaped elements 7 and 8 of the pair is formed at the same position in the tire circumferential direction as that of the other second end of the other of the lateral groove-shaped element 7 and 8 of the pair. At least one pair of the pairs is formed on the land part with the lateral groove-shaped elements 7 and 8 different from each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to tires.

Background Art

[0002] Generally, in the tread portion of a tire, in terms of drainage performance and the like, sipe or transverse grooves extending in the tire axial direction are provided (for example, see Patent Document 1 below). On the other hand, sipe and transverse grooves generate noise during driving.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the quieting of vehicles in recent years, there is also a demand for further improvement in the noise performance of tires, and it is necessary to reduce the driving noise caused by sipe and transverse grooves.

[0005] This disclosure has been devised in view of the above circumstances, and the main object thereof is to provide a tire capable of improving noise performance.

Means for Solving the Problems

[0006] This disclosure relates to a tire having a tread portion, the tread portion comprising a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves, each of the plurality of land portions having a plurality of transverse groove-like elements inclined with respect to the axial direction of the tire and the circumferential direction of the tire, each of the transverse groove-like elements having a first end on a first side in the circumferential direction of the tire and a second end on a second side in the circumferential direction of the tire, and extending linearly from the first end to the second end, the first end and the second end respectively The ends of the centerlines of the transverse groove elements, the plurality of transverse groove elements are arranged in a first arrangement over one circumference of the tire, in the first arrangement, for each pair of adjacent transverse groove elements in the tire circumference, the first end of one transverse groove element of the pair is formed at the same position in the tire circumference as the second end of the other transverse groove element of the pair, and at least one pair of the pairs is a tire in which the transverse groove elements are formed on different parts of the land. [Effects of the Invention]

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

[0008] [Figure 1] This is an exploded view of the tread portion of the tire according to this embodiment. [Figure 2] This is an enlarged view of the first and second land areas in Figure 1. [Figure 3] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 4] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 5] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 6] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 7] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 8]These are enlarged views of the first and second land areas, illustrating other examples. [Figure 9] These are enlarged views of the first, second, and third land areas, illustrating other examples. [Figure 10] These are enlarged views of the first, second, and third land areas, illustrating other examples. [Figure 11] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 12] These are enlarged views of the first and second land areas, illustrating other examples. [Figure 13] This is an exploded view of the tread section, which shows the contact surface with the ground. [Modes for carrying out the invention]

[0009] Several embodiments of this disclosure are described below with reference to the drawings. The drawings may contain exaggerations or representations that differ from the actual structural proportions in order to aid in understanding this disclosure. Furthermore, the same or common elements are denoted by the same reference numerals throughout all embodiments, and redundant descriptions are omitted.

[0010] Figure 1 is a partially exploded view of the tread portion 2 of the tire 1 of this embodiment, and Figure 2 is an enlarged view of the main part of Figure 1. The tire of this embodiment is implemented as, for example, a pneumatic tire. As a pneumatic tire, for example, a passenger car tire is preferred, and a passenger car radial tire is particularly preferred. This disclosure may also be implemented as a motorcycle tire or a heavy-duty tire.

[0011] In Figure 1, tire 1 is considered to be in its normal state. In this specification, the normal state of tire 1 means that tire 1 is mounted on a normal rim with normal internal pressure and is unloaded. Unless otherwise specified, the dimensions of each part of tire 1 are values ​​measured in this normal state.

[0012] In this specification, the "normal rim" is the rim defined for each tire in the standard system including the standards on which the tire is based. For example, in the case of JATMA, it is the "standard rim"; in the case of TRA, it is the "Design Rim"; and in the case of ETRTO, it is the "Measuring Rim".

[0013] In this specification, the "normal internal pressure" is the air pressure defined for each tire in the standard system including the standards on which the tire is based. For JATMA, it is the "maximum air pressure"; for TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it is the "INFLATION PRESSURE".

[0014] As shown in FIG. 1, the tread portion 2 includes a first tread end Te1, a second tread end Te2, and a tread surface 2a formed therebetween. The tread surface 2a is a portion intended to contact the ground when the tire is running and is formed of tread rubber. The first tread end Te1 and the second tread end Te2 are respectively the outermost edges in the tire axial direction at the ground contact surface in the normal load-bearing state.

[0015] In this specification, the "normal load-bearing state" is a state in which a normal load is applied to a tire 1 in a normal state and the tire is brought into contact with a plane with a camber angle of zero. Also, in this specification, the "normal load" is the load defined 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"; and for ETRTO, it is the "LOAD CAPACITY".

[0016] The tread portion 2 is formed with, for example, a plurality (e.g., three) of circumferential grooves 3 extending in the tire circumferential direction. The circumferential grooves 3 of the present embodiment extend linearly, for example, parallel to the tire circumferential direction. Although not particularly limited, in order to ensure sufficient drainage during wet running, the groove width of the circumferential groove 3 is, for example, larger than 2 mm, preferably 3 mm or more, and more preferably 4 mm or more. Similarly, the groove depth of the circumferential groove 3 is, for example, 3 mm or more, preferably 4 mm or more, and more preferably 5 mm or more.

[0017] In the tread portion 2, a plurality of land portions 4 are defined by the plurality of circumferential grooves 3. In the present embodiment, the plurality of land portions 4 are composed of four land portions. The four land portions include, for example, a pair of first land portions 101 and a pair of second land portions 102 arranged on both outer sides in the tire axial direction of the pair of first land portions 101. In the present embodiment, the first land portion 101 forms the crown region of the tread portion 2, and the second land portion 102 forms the shoulder region of the tread portion 2. In FIG. 1, the symbol C indicates the tire equator.

[0018] In the present embodiment, as the plurality of land portions 4, a plurality of lateral groove-like elements are formed in the first land portion 101 and the second land portion 102. Hereinafter, the lateral groove-like element formed in the first land portion 101 is referred to as the "first lateral groove-like element 7", and the lateral groove-like element formed in the second land portion 102 is referred to as the "second lateral groove-like element 8" to distinguish them from each other. These first lateral groove-like elements 7 and second lateral groove-like elements 8 may be collectively referred to as "lateral groove-like elements" without particularly assigning a symbol.

[0019] The first lateral groove-like element 7 and the second lateral groove-like element 8 are each inclined with respect to the tire axial direction and the tire circumferential direction. Therefore, the first lateral groove-like element 7 and the second lateral groove-like element 8 each have a non-zero angle with respect to the tire axial direction and the tire circumferential direction.

[0020] As shown in Figure 2, each of the first transverse groove elements 7 has a first end 7A on the first side S1 in the tire circumferential direction and a second end 7B on the second side S2 in the tire circumferential direction. Similarly, each of the second transverse groove elements 8 has a first end 8A on the first side S1 in the tire circumferential direction and a second end 8B on the second side S2 in the tire circumferential direction.

[0021] The first transverse groove element 7 and the second transverse groove element 8 are both recessed voids from the contact surface of the land portion 4, and represent a comprehensive concept that includes, for example, both sipes and grooves. In the examples of Figures 1 and 2, both the first transverse groove element 7 and the second transverse groove element 8 are formed of sipes. Alternatively, the first transverse groove element 7 and the second transverse groove element 8 may be grooves with a groove width greater than that of sipes.

[0022] In this specification, "sipe" is a slit-shaped void with a width of 2 mm or less, preferably 1.5 mm or less, perpendicular to its longitudinal direction. The sipe functions such that, for example, when in contact with the ground under a normal load, at least a portion of a pair of sipe walls are in contact with each other. Thus, the sipe helps to minimize the reduction in rigidity of the first land section 101 and the second land section 102, and consequently improve steering stability.

[0023] In this specification, "groove" refers to a gap having a longitudinal direction and a width perpendicular thereto, with a groove width greater than 2 mm. There is no particular upper limit to the groove width, but in the case of passenger car tires, it may be 10 mm or less, for example. Such grooves help to improve drainage.

[0024] In this embodiment, the first transverse groove elements 7 and the second transverse groove elements 8 are arranged along one full circumference of the tire according to a first arrangement 10. The first arrangement 10 is a set of multiple first transverse groove elements 7 and multiple second transverse groove elements 8. In the example shown in Figure 1, one set of the first arrangement 10 is formed on two land areas, the first land area 101 and the second land area 102.

[0025] In this disclosure, the first sequence 10 satisfies the following two conditions a and b: a) For every pair of adjacent transverse groove elements in the circumferential direction of the tire, the first end of one transverse groove element of the pair is formed at the same position in the circumferential direction as the second end of the other transverse groove element of the pair; b) At least one pair of all the aforementioned pairs has transverse groove-like elements formed on different land areas.

[0026] Conditions a and b are described in more detail below. In the example in Figure 2, for example, the pair of the uppermost first transverse groove element 7 and the uppermost second transverse groove element 8 is identified as "pair 1". In pair 1, the second end 7B of the first transverse groove element 7 is in the same position as the first end 8A of the second transverse groove element 8 in the tire circumferential direction (see the shorter dashed line extending parallel to the tire axis direction). Therefore, pair 1 satisfies condition a. Also, the first transverse groove element 7 and the second transverse groove element 8 of pair 1 are formed on different parts of the land. Therefore, pair 1 also satisfies condition b.

[0027] Next, for example, we identify the pair of the first transverse groove element 7, which is the second from the top, and the second transverse groove element 8, which is the topmost, as "pair 2". In pair 2, the second end 8B of the second transverse groove element 8 is in the same position in the tire circumferential direction as the first end 7A of the first transverse groove element 7 (see the longer imaginary line extending parallel to the tire axis direction). Therefore, pair 2 satisfies condition a. Also, the first transverse groove element 7 and the second transverse groove element 8 of pair 2 are formed on different parts of the land. Therefore, pair 2 also satisfies condition b.

[0028] In the example in Figure 2, pair 1 and pair 2 are repeated alternately. Therefore, in the first arrangement 10 of the example in Figure 2, each of the pairs has the transverse groove-like elements 7 and 8 included in the pair formed on different land areas.

[0029] Here, whether the first and second ends of the two transverse groove elements are in the same position in the tire circumferential direction is determined using their centerlines (in Figure 2, the centerline 7C of the first transverse groove element 7 and the centerline 8C of the second transverse groove element 8). That is, the first and second ends of the first transverse groove element 7 and the second transverse groove element 8 are identified by the ends of the centerlines 7C and 8C, respectively. However, considering the characteristics of a vulcanized rubber product such as a tire, the term "same position" includes a configuration in which the two ends are offset by a small distance in the tire circumferential direction to allow for manufacturing tolerances. In this case, the distance is 5% or less of the sum of the length L1 of the centerline 7C of the first transverse groove element 7 and the length L2 of the centerline 8C of the second transverse groove element 8 in the tire circumferential direction (L1 + L2), preferably 3% or less, and more preferably 1% or less. Most preferably, the two ends are not offset in the tire circumferential direction.

[0030] Pitch noise is a known type of noise produced when tires are in motion. For example, an impact force is generated each time the land portion elements 11 and 12, separated by the first and second lateral groove elements 7 and 8, come into contact with the road surface. This impact force causes the tread portion 2 and the sidewall portion (not shown) to vibrate periodically, thereby generating pitch noise. However, the first arrangement 10 described above reduces fluctuations in the impact force because the first and second lateral groove elements 7 and 8 make contact with the road surface alternately and continuously during tire movement. Therefore, the tire 1 of this embodiment can improve noise performance by reducing the pitch noise generated from the first and second land portion elements 101 and 102.

[0031] While not particularly limited, in order to further enhance the effects described above, it is desirable that only the first transverse groove-shaped element 7 and the second transverse groove-shaped element 8 constituting the first arrangement 10 be formed on the first land portion 101 and the second land portion 102, as shown in Figure 1.

[0032] In the examples shown in Figures 1 and 2, each pair (pair 1 and pair 2) consists of a first transverse groove element 7 and a second transverse groove element 8 that are inclined toward each other in the same direction (for example, upward to the right) with respect to the circumferential direction of the tire.

[0033] As shown in Figure 3, each pair may consist of a first transverse groove element 7 and a second transverse groove element 8 that are inclined in opposite directions relative to the circumferential direction of the tire.

[0034] Returning to Figure 2, the angles θ1 of the first transverse groove element 7 with respect to the tire circumferential direction and the angle θ2 of the second transverse groove element 8 with respect to the tire circumferential direction are not particularly limited, but from the viewpoint of improving handling stability, they are, for example, 40 degrees or more, preferably 50 degrees or more, and more preferably 60 degrees or more. The upper limit of angles θ1 and θ2 is not limited to less than 90 degrees, but preferably 85 degrees or less, more preferably 80 degrees or less. In this embodiment, angles θ1 and θ2 are equal to each other (θ1=θ2). In other examples, θ1≠θ2 may be the case.

[0035] It is desirable that at least one of the multiple transverse groove elements completely crosses the land portion in the tire axis direction. In the example in Figure 2, the first transverse groove element 7 completely crosses the first land portion 101 in the tire axis direction. Similarly, the second transverse groove element 8 completely crosses the second land portion 102 in the tire axis direction. In such an embodiment, the first land portion 101 and the second land portion 102 provide excellent drainage.

[0036] In other examples, at least one of the transverse groove elements may terminate within the land area at at least one of its first and second ends. For example, as shown in Figure 4, each of the first transverse groove elements 7 may terminate within the first land area 101 at at least one of its first end 7A and second end 7B. In the example in Figure 4, in each of the first transverse groove elements 7, the first end 7A terminates within the first land area 101, and the second end 7B communicates with the circumferential groove 3. Similarly, each of the second transverse groove elements 8 may terminate within the second land area 102 at at least one of its first end 8A and second end 8B. In the example in Figure 4, in each of the second transverse groove elements 8, the second end 8B terminates within the second land area 102, and the first end 8A communicates with the circumferential groove 3. In such embodiments, the reduction in rigidity of the first land area 101 and the second land area 102 is minimized, and steering stability is improved.

[0037] Figure 5 shows yet another example. Figure 5 differs from Figure 4 in that the direction of the inclination of the first transverse groove element 7 is reversed. It also differs in that the second end 7B of the first transverse groove element 7 communicates with the circumferential groove 3 on the opposite side from the second land portion 102. In this example, a rib element 14 continuous in the tire circumferential direction can be formed on one side (the left side in Figure 5) of the tire axial direction of the first land portion 101 and the second land portion 102. This embodiment is applicable to tires in which the orientation of mounting to the vehicle is specified, and it is desirable that, for example, the second land portion 102 side is located on the outside of the vehicle when mounted on the vehicle. This further improves handling stability. To improve handling stability, the width of the rib element 14 in the tire axial direction is preferably 20% or more, more preferably 25% to 50%, of the width of the first land portion 101 in the tire axial direction.

[0038] Figure 6 shows yet another example. Figure 6 differs from the example described above in that the first transverse groove element 7 and / or the second transverse groove element 8 extend non-linearly.

[0039] The first transverse groove-like element 7 is connected such that, for example, a linearly extending first inclined portion 71 and a linearly extending second inclined portion 72 constitute a bent portion. In this embodiment, the first inclined portion 71 includes a second end 7B, and the second inclined portion 72 includes a first end 7A. The first end 7A terminates within the first land portion 101. As a result, the first land portion 101 may have a rib element 14 that extends continuously in the circumferential direction of the tire to the left of the first end 7A.

[0040] The angle θ11 of the first inclined portion 71 with respect to the tire circumferential direction is greater than the angle θ12 of the second inclined portion 72 with respect to the tire circumferential direction. With respect to the angle of the lateral groove-shaped element with respect to the tire circumferential direction, the larger the angle, the more advantageous it is for handling stability. Also, when the vehicle is turning, the force acting near the edge of the ground portion tends to be greater. In this embodiment, the angle θ11 of the first inclined portion 71 located at the edge of the first ground portion 101 is greater than the angle θ12 of the second inclined portion 72, which further improves handling stability. In addition, uneven wear near the edge of the first ground portion 101 where the first inclined portion 71 is open is suppressed. Furthermore, by bending the first lateral groove-shaped element 7 as described above, adjacent ground portion elements 11 can more easily support each other when the tire is running. This helps to further improve handling stability. The steeper incline of the second inclined portion 72 helps to reduce the impact force when the tire touches the ground.

[0041] To further enhance the effects described above, the angle θ11 of the first inclined portion 71 with respect to the tire circumferential direction is, for example, 50 degrees or more, preferably 60 degrees or more. Furthermore, the upper limit of the angle θ11 is not limited to 90 degrees, but is preferably 85 degrees or less, more preferably 80 degrees or less. Similarly, the angle θ12 of the second inclined portion 72 with respect to the tire circumferential direction is, for example, 20 degrees or more, preferably 30 degrees or more, preferably 70 degrees or less, more preferably 60 degrees or less.

[0042] The second transverse groove element 8 extends, for example, to completely traverse the second land portion 102 in the tire axis direction. The second transverse groove element 8 in this embodiment comprises a third inclined portion 83, a fourth inclined portion 84, and a fifth inclined portion 85, each inclined portion extending in a straight line. The third inclined portion 83 is the portion including the first end 8A. The fifth inclined portion 85 is the portion including the second end 8B. The fourth inclined portion 84 is the portion between the third inclined portion 83 and the fifth inclined portion 85. In this embodiment, the third inclined portion 83, the fourth inclined portion 84, and the fifth inclined portion 85 are connected to form a bend. In a preferred embodiment, each bend may be formed by an arc portion with a radius of curvature R.

[0043] In this embodiment, the angle θ23 of the third inclined portion 83 with respect to the tire circumferential direction and the angle θ25 of the fifth inclined portion 85 with respect to the tire circumferential direction are smaller than the angle θ24 of the fourth inclined portion 84 with respect to the tire circumferential direction. As a result, when turning, the land portion elements 12 of the second land portion 102 can engage with each other and support each other effectively. In addition, by having the second lateral groove-shaped element 8 equipped with the fourth inclined portion 84 with a relatively large angle, deterioration of the lateral rigidity of the land portion elements 12 can be suppressed. As a result, the second land portion 102 of this embodiment helps to exhibit excellent handling stability.

[0044] To further enhance the above-mentioned effects, the angles θ23 of the third inclined portion 83 with respect to the tire circumferential direction and the angle θ25 of the fifth inclined portion 85 with respect to the tire circumferential direction are, for example, 20 degrees or more, preferably 30 degrees or more, while preferably 80 degrees or less, more preferably 70 degrees or less. Similarly, the angle θ24 of the fourth inclined portion 84 with respect to the tire circumferential direction is, for example, 50 degrees or more, preferably 60 degrees or more, preferably 85 degrees or less, more preferably 80 degrees or less. In a preferred embodiment, considering the order of contact with the ground, it is desirable that the angles of adjacent inclined portions of these five inclined portions alternate between large and small. That is, it is desirable that the following be satisfied. As a result, the noise frequencies caused by the first transverse groove element 7 and the second transverse groove element 8 are dispersed over a wide frequency band, further improving noise performance. θ12 < θ11 θ11 > θ23 θ23 < θ24 θ24 > θ25

[0045] In the example in Figure 6, a curved groove is shown as a non-linear transverse groove element. In other examples, the transverse groove element may be a curved groove with a continuously changing angle, or a composite groove of such a curved groove and a straight groove.

[0046] Figure 7 shows yet another example of the first arrangement 10. In the example of Figure 7, the lateral groove elements include a first lateral groove element 7 and a second lateral groove element 8. The angle of one of the first lateral groove element 7 and the second lateral groove element 8 with respect to the tire circumferential direction is greater than the angle of the other of the first lateral groove element 7 and the second lateral groove element 8 with respect to the tire circumferential direction. Also, the groove width (sipe width) of one of the first lateral groove element 7 and the second lateral groove element 8 is smaller than the groove width (sipe width) of the other. In the example of Figure 7, the angle θ2 of the second lateral groove element 8 is greater than the angle θ1 of the first lateral groove element 7, and the groove width (sipe width) W2 of the second lateral groove element 8 is smaller than the groove width (sipe width) W1 of the first lateral groove element 7. In this embodiment, in a cross-section of the land portion perpendicular to the contact surface of the land portions 101 and 102 and parallel to the tire axis direction, the opening width of the first transverse groove element 7 and the opening width of the second transverse groove element 8 are approximately equal to or equal to each other. This helps to further reduce fluctuations in impact force during tire travel and to further improve noise performance.

[0047] Figure 8 shows yet another example of the first arrangement 10. In the example of Figure 8, at least one pair of adjacent pairs of transverse groove elements in the circumferential direction of the tire is such that the transverse groove elements are formed on the same land area. For example, in the first land area 101, the first transverse groove elements 7 consist of a first right transverse groove element 7R and a first left transverse groove element 7L, which are alternately arranged in the circumferential direction of the tire. In the second land area 102, the second transverse groove element 8, as described in Figure 4, is formed.

[0048] In this example, the first array 10 consists of three types of pairs of adjacent lateral groove-shaped elements in the circumferential direction of the tire: pair 1, pair 2, and pair 3.

[0049] Pair 1 consists, for example, of a first left transverse groove element 7L drawn at the very top of the first land portion 101, and a first right transverse groove element 7R adjacent to it on the second side S2 in the tire circumferential direction. In this pair 1, the second end 7LB of the first left transverse groove element 7L and the first end 7RA of the first right transverse groove element 7R are at the same position in the tire circumferential direction. Therefore, the transverse groove elements that constitute pair 1 are formed on the same land portion (first land portion 101).

[0050] Pair 2 follows the second side S2 of Pair 1. Pair 2 consists, for example, the first right-side lateral groove element 7R drawn at the top of the first right-side lateral groove element 7R of the first land portion 101, and the second lateral groove element 8 adjacent to it on the second side S2. In this pair 2, the second end 7RB of the first right-side lateral groove element 7R and the first end 8A of the second lateral groove element 8 are at the same position in the circumferential direction of the tire. Therefore, Pair 2 is a pair in which the lateral groove elements that constitute it are formed on different land portions (first land portion 101 and second land portion 102).

[0051] Pair 3 follows the second side S2 of pair 2. Pair 3 consists, for example, of a second transverse groove element 8 on the second land portion 102 and a first left transverse groove element 7L adjacent to it on the second side S2. In this pair 3, the second end 8B of the second transverse groove element 8 and the first end 7LA of the first left transverse groove element 7L are at the same position in the circumferential direction of the tire. Therefore, pair 3 is a pair in which the transverse groove elements constituting it are formed on different land portions (first land portion 101 and second land portion 102).

[0052] Thus, in at least one pair of the first array 10, the transverse groove-shaped elements constituting the pair may be formed on the same land area, and the above-described effect can be achieved in this example as well. In the example of Figure 8, two types of transverse groove-shaped elements are provided on the first land area 101, but instead of this, or together with this, two types of transverse groove-shaped elements may be provided on the second land area 102. Furthermore, there may be three or more types of transverse groove-shaped elements provided on a single land area.

[0053] Figure 9 shows yet another example of the first arrangement 10. In the example in Figure 9, the transverse groove-like elements constituting the first arrangement 10 are formed in two land sections, but differ from the previous example in that two or more circumferential grooves are arranged between the two land sections. That is, in the previous examples of the first arrangement 10, the first land section 101 and the second land section 102 were adjacent with one circumferential groove 3 in between. In contrast, in the example in Figure 9, two or more circumferential grooves 3 may be arranged between the first land section 101 and the second land section 102. Also, for example, a third land section 103 is arranged between the first land section 101 and the second land section 102. The third land section 103 is a rib that is continuous in the circumferential direction of the tire. The third land section may be, for example, a plain rib without grooves or sipes.

[0054] Figure 10 shows yet another example of the first arrangement 10. As in the example in Figure 10, the lateral groove elements constituting the first arrangement 10 may be arranged in three or more of the multiple land sections. In the example in Figure 10, the first arrangement 10 is arranged in three land sections: the first land section 101, the second land section 102, and the third land section 103. In the third land section 103, multiple third lateral groove elements 9 are formed in the circumferential direction of the tire as lateral groove elements. This first arrangement 10 consists of three types: pair 1, pair 2, and pair 3. Pair 1 consists of a first lateral groove element 7 and a second lateral groove element 8. Pair 2 is located on the second side S2 of pair 1 and consists of a second lateral groove element 8 and a third lateral groove element 9. Pair 3 is located on the second side S2 of pair 2 and consists of a third lateral groove element 9 and a first lateral groove element 7. In each of these pairs, the transverse groove-like elements constituting the pair are formed in different land areas. The first arrangement 10 may be formed in four or more land areas.

[0055] Figure 11 shows another embodiment of the present disclosure. In this embodiment, multiple sets of the first array 10 are formed on the first land section 101 and the second land section 102. For example, the multiple sets of the first array 10 include an inner first array 10X and another outer first array 10Y. In this embodiment as well, by reducing pitch noise, it is possible to improve steering stability performance while improving noise performance.

[0056] In Figure 11, the inner first array 10X is composed of a first transverse groove element 7X and a second transverse groove element 8X. The first transverse groove element 7X is formed on the second land portion 102 side of the first land portion 101. The second transverse groove element 8X is formed on the first land portion 101 side of the second land portion 102. In Figure 11, the first transverse groove element 7X and the second transverse groove element 8X that constitute the inner first array 10X are blacked out to aid understanding.

[0057] The outer first array 10Y is composed of a first transverse groove element 7Y and a second transverse groove element 8Y. The first transverse groove element 7Y is formed on the side of the first land portion 101 opposite to the second land portion 102. The second transverse groove element 8Y is formed on the side of the second land portion 102 opposite to the first land portion 101. In Figure 11, the first transverse groove element 7Y and the second transverse groove element 8Y that constitute the outer first array 10Y are not filled in in order to facilitate distinction from the inner first array 10X.

[0058] Thus, even if multiple sets of the first array 10 are provided in the land area consisting of the first land area 101 and the second land area 102, noise performance can be improved by reducing pitch noise, similar to the previous embodiment.

[0059] Figure 12 shows another example of a transverse groove element. In this example, the transverse groove element is a transverse groove (inclined groove) It is configured as follows. Specifically, the lateral groove elements of the first array 10 in this example include, for example, a first lateral groove element 7 and a second lateral groove element 8, which are formed by lateral grooves. Thus, the lateral groove elements of this disclosure (first lateral groove element 7 and second lateral groove element 8) are not limited to sipes.

[0060] Figure 13 shows the contact surface GL of the tread section 2 in Figure 1 under normal load conditions as a dashed line. The tire circumferential length D1 of the edge GL1 of the contact surface GL crossing the first land section 101 is set to be 20% or less of the tire circumferential length L1 of one of the first transverse groove elements 7. Similarly, the tire circumferential length D2 of the edge GL2 of the contact surface GL crossing the second land section 102 is set to be 20% or less of the tire circumferential length L2 of one of the second transverse groove elements 8.

[0061] The inventors focused on the relationship between the tire circumferential lengths L1 and L2 of the first transverse groove element 7 and the second transverse groove element 8, and the tire circumferential lengths D1 and D2 of the respective contact surface edges GL1 and GL2 of the contact surface GL. In order to obtain the impact force fluctuation suppression effect expected by the first array 10, it is most effective for the contact surface edges GL1 and GL2 crossing each land portion 101 and 102 to be parallel to the tire axis direction. However, in actual tires, the contact surface edges GL1 and GL2 tend to be arc-shaped, as shown in Figure 13. Even in such cases, if the tire circumferential lengths D1 and D2 of the contact surface edges GL1 and GL2 are 20% or less of the tire circumferential length L1 of the first transverse groove element 7 and the tire circumferential length L2 of the second transverse groove element 8, respectively, the timing difference in contact between the first edge e1 and the second edge e2 of the land portion 4 can be minimized. This helps to further reduce the fluctuations in impact force described above and to further improve noise performance. In a particularly desirable embodiment, the length D1 is 10% or less, more preferably 5% or less, of the tire circumferential length L1 of one of the first transverse groove elements 7, and the length D2 is 10% or less, more preferably 5% or less, of the tire circumferential length L2 of one of the second transverse groove elements 8.

[0062] Although several embodiments of this disclosure have been described above, the specific configurations shown in the embodiments and drawings are for the purpose of understanding the content of this disclosure, and this disclosure is not limited to the specific configurations shown.

[0063] [Note] This disclosure includes the following aspects.

[0064] [Disclosure 1] A tire having a tread portion, The tread portion includes a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves. Each of the aforementioned land portions has a plurality of transverse groove-like elements formed therein, which are inclined with respect to the tire axis direction and the tire circumferential direction. Each of the aforementioned lateral groove-shaped elements has a first end on the first side in the tire circumferential direction and a second end on the second side in the tire circumferential direction, and extends linearly from the first end to the second end. The first end and the second end are, respectively, the ends of the centerline of the transverse groove-shaped element. The plurality of transverse groove-like elements are arranged in a first arrangement over one full turn in the circumferential direction of the tire. In the first arrangement, for each pair of adjacent transverse groove elements in the tire circumferential direction, the first end of one transverse groove element of the pair is formed at the same position in the tire circumferential direction as the second end of the other transverse groove element of the pair. At least one of the aforementioned pairs is such that the transverse groove-like elements are formed on different parts of the land. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the aforementioned lateral groove-like element includes a sipe with a width of 2 mm or less. [Disclosure 3] The tire according to disclosure 1 or 2, wherein the aforementioned lateral groove-like element includes a groove with a width greater than 2 mm. [Disclosure 4] The tire according to any one of the pairs of transverse groove elements, wherein at least one of the transverse groove elements is inclined toward the same direction with respect to the circumferential direction of the tire. [Disclosure 5] The tire according to any one of claims 1 to 4, wherein at least one of the pair of transverse groove elements consists of transverse groove elements that are inclined in different directions from each other with respect to the circumferential direction of the tire. [Disclosure 6] The tire according to any one of the plurality of transverse groove-like elements, wherein at least one of the plurality of transverse groove-like elements completely crosses the land portion in the tire axis direction. [Disclosure 7] The tire according to any one of claims 1 to 6 of this disclosure, wherein at least one of the lateral groove-like elements has at least one of the first and second ends terminated within the land portion. [Disclosure 8] The aforementioned transverse groove element includes a first transverse groove element and a second transverse groove element. The angle of one of the first transverse groove element and the second transverse groove element with respect to the tire circumferential direction is greater than the angle of the other of the first transverse groove element and the second transverse groove element with respect to the tire circumferential direction. The tire according to any one of claims 1 to 7 of this disclosure, wherein the groove width of one of the first transverse groove element and the second transverse groove element is smaller than the groove width of the other. [Disclosure 9] The tire according to any one of claims 1 to 8 of this disclosure, wherein the tire is mounted on a regular rim with regular internal pressure and, under a regular load, is in contact with a plane with a camber angle of zero at the contact surface, and the circumferential length of the edge of the contact surface that crosses the land portion on which the transverse groove-like elements constituting the first arrangement are provided is 20% or less of the circumferential length of one of the transverse groove-like elements formed on the land portion in the circumferential direction of the tire. [Disclosure 10] A tire according to any one of claims 1 to 9 of this disclosure, wherein the first array is formed in multiple sets. [Disclosure 11] The tire according to any one of claims 1 to 10, wherein each of the pairs comprises two of the transverse groove elements formed on different land portions of the pair. [Disclosure 12] The tire according to any one of the above-mentioned pairs, wherein at least one of the aforementioned pairs has two of the aforementioned lateral groove-like elements formed on the same land portion. [Disclosure 13] The tire according to any one of claims 1 to 12, wherein the transverse groove-like elements constituting the first arrangement are formed on two of the plurality of land portions. [Disclosure 14] The tire according to disclosure 13, wherein the two land portions are adjacent to each other via one of the circumferential grooves. [Disclosure 15] The tire according to disclosure 13, wherein two or more of the circumferential grooves are arranged between the two land portions. [Disclosure 16] The tire according to any one of claims 1 to 12 of this disclosure, wherein the lateral groove-shaped elements constituting the first arrangement are arranged in three or more of the plurality of land portions. [Explanation of Symbols]

[0065] 1 tire 2 Tread section 4 Land 7. First transverse groove element 7A First end of the first transverse groove element 7B Second end of the first transverse groove element 8. Second transverse groove element 8A First end of the second transverse groove element 8B Second end of the second transverse groove element 10 First sequence GLa contact surface edge S1 First side S2 Second side

Claims

1. A tire having a tread portion, The tread portion includes a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves. Each of the aforementioned land portions has a plurality of transverse groove-like elements formed therein, which are inclined with respect to the tire axis direction and the tire circumferential direction. Each of the aforementioned lateral groove-shaped elements has a first end on the first side in the tire circumferential direction and a second end on the second side in the tire circumferential direction, and extends linearly from the first end to the second end. The first end and the second end are, respectively, the ends of the centerline of the transverse groove-shaped element. The plurality of transverse groove-shaped elements are arranged in a first arrangement over one full turn in the circumferential direction of the tire. In the first arrangement, for each pair of adjacent transverse groove elements in the tire circumferential direction, the first end of one transverse groove element of the pair is formed at the same position in the tire circumferential direction as the second end of the other transverse groove element of the pair. At least one of the aforementioned pairs has the transverse groove-like elements formed on different land portions, At least one of the pair of lateral groove elements consists of lateral groove elements that are inclined in the same direction relative to the circumferential direction of the tire. tire.

2. A tire having a tread portion, The tread portion includes a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves. Each of the aforementioned land portions has a plurality of transverse groove-like elements formed therein, which are inclined with respect to the tire axis direction and the tire circumferential direction. Each of the aforementioned lateral groove-shaped elements has a first end on the first side in the tire circumferential direction and a second end on the second side in the tire circumferential direction, and extends linearly from the first end to the second end. The first end and the second end are, respectively, the ends of the centerline of the transverse groove-shaped element. The plurality of transverse groove-shaped elements are arranged in a first arrangement over one full turn in the circumferential direction of the tire. In the first arrangement, for each pair of adjacent transverse groove elements in the tire circumferential direction, the first end of one transverse groove element of the pair is formed at the same position in the tire circumferential direction as the second end of the other transverse groove element of the pair. At least one of the aforementioned pairs has the transverse groove-like elements formed on different land portions. The aforementioned transverse groove-shaped element includes a first transverse groove-shaped element and a second transverse groove-shaped element. The angle of one of the first transverse groove element and the second transverse groove element with respect to the tire circumferential direction is greater than the angle of the other of the first transverse groove element and the second transverse groove element with respect to the tire circumferential direction. The groove width of one of the first transverse groove element and the second transverse groove element is smaller than the groove width of the other. tire.

3. The tire according to claim 1 or 2, wherein the transverse groove-shaped elements constituting the first arrangement are formed in two of the plurality of land portions.

4. The tire according to claim 3, wherein the two land portions are adjacent to each other via one of the circumferential grooves.

5. A tire having a tread portion, The tread portion includes a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves. Each of the aforementioned land portions has a plurality of transverse groove-like elements formed therein, which are inclined with respect to the tire axis direction and the tire circumferential direction. Each of the aforementioned lateral groove-shaped elements has a first end on the first side in the tire circumferential direction and a second end on the second side in the tire circumferential direction, and extends linearly from the first end to the second end. The first end and the second end are, respectively, the ends of the centerline of the transverse groove-shaped element. The plurality of transverse groove-shaped elements are arranged in a first arrangement over one full turn in the circumferential direction of the tire. In the first arrangement, for each pair of adjacent transverse groove elements in the tire circumferential direction, the first end of one transverse groove element of the pair is formed at the same position in the tire circumferential direction as the second end of the other transverse groove element of the pair. At least one of the aforementioned pairs has the transverse groove-like elements formed on different land portions. The transverse groove-shaped elements constituting the first arrangement are formed on two of the multiple land portions, Between the two land areas, two or more of the circumferential grooves are provided. tire.

6. A tire having a tread portion, The tread portion includes a plurality of circumferential grooves extending continuously in the circumferential direction of the tire, and a plurality of land portions separated by the circumferential grooves. Each of the aforementioned land portions has a plurality of transverse groove-like elements formed therein, which are inclined with respect to the tire axis direction and the tire circumferential direction. Each of the aforementioned lateral groove-shaped elements has a first end on the first side in the tire circumferential direction and a second end on the second side in the tire circumferential direction, and extends linearly from the first end to the second end. The first end and the second end are, respectively, the ends of the centerline of the transverse groove-shaped element. The plurality of transverse groove-shaped elements are arranged in a first arrangement over one full turn in the circumferential direction of the tire. In the first arrangement, for each pair of adjacent transverse groove elements in the tire circumferential direction, the first end of one transverse groove element of the pair is formed at the same position in the tire circumferential direction as the second end of the other transverse groove element of the pair. At least one of the aforementioned pairs has the transverse groove-like elements formed on different land portions. The transverse groove-shaped elements constituting the first arrangement are arranged in three or more of the multiple land areas. tire.

7. The tire according to any one of claims 1 to 6, wherein the aforementioned lateral groove-like element includes a sipe with a width of 2 mm or less.

8. The tire according to any one of claims 1 to 7, wherein the aforementioned lateral groove-like element includes a groove with a width greater than 2 mm.

9. The tire according to any one of claims 1 to 8, wherein at least one of the pairs of lateral groove elements consists of lateral groove elements that are inclined in directions different from each other with respect to the circumferential direction of the tire.

10. The tire according to any one of claims 1 to 9, wherein at least one of the plurality of lateral groove-like elements completely crosses the land portion in the tire axis direction.

11. The tire according to any one of claims 1 to 10, wherein at least one of the lateral groove-shaped elements has at least one of the first end and the second end terminated within the land portion.

12. The tire according to any one of claims 1 to 11, wherein the tire is mounted on a regular rim with regular internal pressure and, under a regular load, is in contact with a plane with a camber angle of zero on the contact surface, and the circumferential length of the edge of the contact surface that crosses the land portion on which the transverse groove-like elements constituting the first arrangement are provided is 20% or less of the circumferential length of one of the transverse groove-like elements formed on the land portion in the tire.

13. The tire according to any one of claims 1 to 12, wherein the first arrangement is formed in multiple sets.

14. The tire according to any one of claims 1 to 13, wherein each of the pairs has two of the lateral groove-like elements included in the pair formed on different land portions.

15. The tire according to any one of claims 1 to 13, wherein at least one of the pairs has two of the lateral groove-like elements included in the pair formed on the same land portion.

Images