JP5767659B2 - Motorcycle tires - Google Patents

Description

  The present invention relates to a motorcycle having improved roll characteristics.

  Motorcycle tires are required to improve transient characteristics (hereinafter also referred to as “roll characteristics”) when a camber angle is given in order to improve turning performance.

  Specifically, motorcycle tires are required to easily roll the vehicle body at the beginning of the roll with a small camber angle. For this reason, it is desirable that the rigidity of the crown area to be grounded at the initial stage of the roll is smaller than the rigidity of the shoulder area and the middle area.

  In addition, a tire for a motorcycle is required to easily suppress the camber angle from the middle stage to the end stage of the roll with a large camber angle. For this reason, it is desirable that the rigidity of the shoulder region to be grounded at the time of full bank is larger than the rigidity of the middle region and the crown region. Furthermore, it is desirable that the tread portion of the motorcycle tire has a smooth rigidity distribution from the crown region to the shoulder region.

  However, when the land ratio of the crown portion is decreased and the land ratio of the shoulder portion is increased in order to improve the roll characteristics, there is a problem that grip performance, wear resistance performance, and the like are deteriorated.

  The following Patent Document 1 proposes a motorcycle tire that can improve the stability during braking while improving the lightness of handling by optimizing the tread pattern.

JP 2007-223453 A

  However, even the motorcycle tire described in Patent Document 1 is not sufficient for achieving both roll characteristics, grip performance, and wear resistance performance, and further improvements are required.

  The present invention has been devised in view of the actual situation as described above, and based on improving the position and shape of each groove provided in the tread portion, without reducing the grip performance and wear resistance performance. The main object is to provide motorcycle tires with improved roll characteristics.

Of the present invention, the invention according to claim 1 is a motorcycle tire having a tread portion in which a tread pattern in which a rotation direction is specified is formed, and showing the tread pattern of the tread portion. The tread portion includes a first region on one tread end side from the tire equator and a second region on the other tread end side from the tire equator, and the tire equator side in each of the first region and the second region. A plurality of inner inclined grooves provided on the tread end side and a plurality of outer inclined grooves provided on the tread end side are provided, and the inner inclined groove is a first inner inclined groove provided in the first region. And a second inner inclined groove provided in the second region, wherein the first inner inclined groove and the second inner inclined groove are respectively opposite to the rotational direction from the inner end in the tire axial direction. Heading to The outer inclined groove includes a first outer inclined groove provided in the first region and a second outer inclined groove provided in the second region; The first outer inclined groove and the second outer inclined groove respectively extend from the inner end in the tire axial direction toward the outer end in the tire axial direction toward the rotational direction, and the first region and the second region , The tire circumferential direction length B1 of the outer inclined groove is smaller than the tire circumferential direction length A1 of the inner inclined groove, and the tire axial direction along the tread contact surface of the outer inclined groove the length of the B2, the greater the tire axial length A2 along the tread surface of the inner inclined groove, the first inner inclined groove, and said second inner inclined grooves, projected on the tire equator The inner slope at both ends of the groove when Than 0% of the tire circumferential direction of the length has an overlap length of the large and 10% or less in the tire circumferential direction, said first outer inclined groove, said a second outer inclined grooves, each tire equator It provided without overlapping each other when projected, in each of the first region and the second region, and said inner inclined groove, and the outer inclined groove is provided alternately in the tire circumferential direction, wherein The outer inclined grooves do not overlap the inner inclined grooves when projected in the tire axial direction, and the first outer inclined grooves are projected in the tire axial direction projected on the second inner inclined grooves. A distance D1 in the tire circumferential direction between the outer end of the first outer inclined groove and the inner end of the second inner inclined groove, provided without protruding from within the region P2, and the inner side of the first outer inclined groove; The tire circumference between the end and the outer end of the second inner inclined groove The direction distance D2 is 30 to 70% of the length (A1-B1), and each of the second outer inclined grooves is a projection region P1 projected in the tire axial direction of each of the first inner inclined grooves. A distance D1 in the tire circumferential direction between the outer end of the second outer inclined groove and the inner end of the first inner inclined groove; and the inner end of the second outer inclined groove; A distance D2 in the tire circumferential direction from the outer end of the first inner inclined groove is 30 to 70% of the length (A1-B1).

According to a second aspect of the present invention, the tread portion includes a crown region that is a region of 40% of the tread deployment width centered on the tire equator, and 20% of the tread deployment width from the end of each tread to the tire equator side. A shoulder region, and a middle region between the crown region and the shoulder region, a land ratio Lc of the crown region, a land ratio Lm of the middle region, and a land ratio Ls of the shoulder region are: The motorcycle tire according to claim 1, which satisfies the following relationship.
Lc <Ls
Lc ≦ Lm ≦ Ls

  According to a third aspect of the present invention, the inner end of each inner inclined groove is located in a range of 1.5 to 5% of the tread deployment width from the tire equator, and the outer end of each inner inclined groove is The motorcycle tire according to claim 1 or 2, which is located in a range of 15 to 25% of a tread developed width from the tire equator.

  According to a fourth aspect of the present invention, in each of the inner inclined grooves, an angle with respect to the tire circumferential direction is 0 to 30 °, and the angle gradually increases toward the outer side in the tire axial direction. A motorcycle tire according to any one of the above.

  The invention according to claim 5 is the motorcycle tire according to any one of claims 1 to 4, wherein each of the inner inclined grooves has a groove width that gradually decreases toward the outer side in the tire axial direction.

  According to a sixth aspect of the present invention, the inner end of each outer inclined groove is located in a range of 15 to 25% of the tread deployment width from the tire equator, and the outer end of each outer inclined groove is a tire. The motorcycle tire according to any one of claims 1 to 5, wherein the tire is located in a range of 32.5 to 42.5% of a tread development width from the equator.

  According to a seventh aspect of the present invention, each of the outer inclined grooves has an angle with respect to the tire circumferential direction of 30 to 90 °, and the angle gradually increases toward the outer side in the tire axial direction. A motorcycle tire according to any one of the above.

  The invention according to claim 8 is the motorcycle tire according to any one of claims 1 to 7, wherein each of the outer inclined grooves has a groove width that gradually decreases toward the outer side in the tire axial direction.

  The motorcycle tire of the present invention has a tread portion in which a tread pattern in which a rotation direction is specified is formed. The tread portion includes a first region on one tread end side from the tire equator and a second region on the other tread end side from the tire equator.

  A plurality of inner inclined grooves provided on the tire equator side and a plurality of outer inclined grooves provided on the tread end side are provided in each of the first region and the second region. The inner inclined groove includes a first inner inclined groove provided in the first region and a second inner inclined groove provided in the second region. Each of the first inner inclined groove and the second inner inclined groove extends from the inner end in the tire axial direction toward the outer end in the tire axial direction in the direction opposite to the rotational direction. The outer inclined groove includes a first outer inclined groove provided in the first region and a second outer inclined groove provided in the second region. The first outer inclined groove and the second outer inclined groove respectively extend from the inner end in the tire axial direction toward the outer end in the tire axial direction in the rotational direction. Such a motorcycle tire has a tread portion having a uniform rigidity distribution in the tire axial direction, and exhibits excellent roll characteristics.

  In each of the first region and the second region, the length B1 of the outer inclined groove in the tire circumferential direction is smaller than the length A1 of the inner inclined groove in the tire circumferential direction, and is along the tread contact surface of the outer inclined groove. The length B2 in the tire axial direction is larger than the length A2 in the tire axial direction along the tread contact surface of the inner inclined groove. In such a motorcycle tire, the rigidity of the shoulder region in the tire axial direction is larger than the rigidity of the crown region in the tire axial direction. For this reason, it becomes easy to give a camber angle at the beginning of the roll, and it becomes easy to suppress the camber angle at the end of the roll. For this reason, the outstanding roll characteristic is acquired.

The first inner inclined groove and the second inner inclined groove, when projected to the tire equator, the grooves both ends of the inner inclined grooves to the tire circumferential direction of the length of the large and 10% or less than 0% It has an overlapping length in the tire circumferential direction. Such first inner inclined grooves and second inner inclined grooves make the rigidity of the tread portion in the crown region appropriate, and improve the roll characteristics at the initial stage of the roll without deteriorating grip performance and wear resistance performance.

The first outer inclined groove and the second outer inclined groove is provided without overlapping each other when projected on the tire equator, respectively. Each first outer inclined groove is provided without protruding from within the projection region P2 projected in the tire axial direction of each second inner inclined groove. The distance D1 in the tire circumferential direction between the outer end of the first outer inclined groove and the inner end of the second inner inclined groove, and the tire circumferential direction between the inner end of the first outer inclined groove and the outer end of the second inner inclined groove The distance D2 is 30 to 70% of the length (A1-B1). Each second outer inclined groove is provided without protruding from the projection region P1 projected in the tire axial direction of each first inner inclined groove. The distance D1 in the tire circumferential direction between the outer end of the second outer inclined groove and the inner end of the first inner inclined groove, and the tire circumferential direction between the inner end of the second outer inclined groove and the outer end of the first inner inclined groove The distance D2 is 30 to 70% of the length (A1-B1).

  Such an inner inclined groove and an outer inclined groove smooth the rigidity distribution of the tread portion from the crown region to the shoulder region, and improve the roll characteristics. Further, the inner inclined groove and the outer inclined groove relatively increase the rigidity of the tread portion in the vicinity of the middle region and the shoulder region. For this reason, it becomes easy to suppress the camber angle at the end of the roll, and the roll characteristics are improved.

1 is a cross-sectional view showing an example of a motorcycle tire according to the present invention. It is an expanded view which shows the tread pattern of the tread part of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a tire meridian cross-sectional view including a tire rotation axis in a normal state of a motorcycle tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment. FIG. 2 is a development view showing a tread pattern of the tread portion 2 of the tire 1. 1 is a cross-sectional view taken along the line AA in FIG. A tire 1 in FIG. 1 is a tire for a front wheel for road racing.

  The “normal state” is a no-load state in which the tire 1 is assembled to a normal rim (not shown) and filled with a normal internal pressure. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in this normal state.

  The “regular rim” is a rim determined for each tire in a standard system including a standard on which a tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, For ETRTO, "Measuring Rim".

  The “regular internal pressure” is the air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based, and is “maximum air pressure” for JATMA, and “TIRE LOAD” for TRA. The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” in the case of ETRTO.

  In the tire 1 of the present embodiment, the outer surface 2s between the tread ends 2t and 2t of the tread portion 2 is convex in an arcuate shape outward in the tire radial direction so that a sufficient contact area can be obtained even when turning with a large camber angle. Curved and extended. The tread width TW, which is the distance in the tire axial direction between the tread ends 2t and 2t, forms the maximum tire width.

  The tire 1 includes a carcass 6 extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a belt layer 7 disposed on the outer side in the tire radial direction of the carcass 6 and inward of the tread portion 2. Have.

  The carcass 6 is constituted by, for example, one carcass ply 6A. The carcass ply 6A includes a main body portion 6a and a folded portion 6b. The main body portion 6 a extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 embedded in the bead portion 4. The folded portion 6b is connected to the main body portion 6a and is folded around the bead core 5 from the inner side in the tire axial direction to the outer side. A bead apex rubber 8 is disposed between the main body portion 6a and the folded portion 6b of the carcass ply 6A. The bead apex rubber 8 is made of hard rubber and extends outward from the bead core 5 in the tire radial direction.

  The carcass ply 6A has a carcass cord arranged with an inclination of, for example, 65 to 90 degrees with respect to the tire equator C. As the carcass cord, for example, an organic fiber cord such as nylon, polyester, or rayon is suitably employed.

  The belt layer 7 is composed of, for example, two belt plies 7A and 7B. The two belt plies 7A and 7B are overlapped in the tire radial direction so that the belt cords cross each other. For example, the belt cord is inclined at an angle of 15 to 25 ° with respect to the tire equator C. As the belt cord, for example, an organic fiber cord such as aramid or rayon is suitably employed.

  As shown in FIG. 2, the rotation direction R is designated for the tire 1 of the present invention. The tread portion 2 includes a crown region Cr that is a region of 40% of the tread deployment width TWe centered on the tire equator C, and a shoulder that is a region of 20% of the tread deployment width TWe from each tread end 2t to the tire equator C side. The region Sh includes a middle region Mi between the crown region Cr and the shoulder region Sh.

  The tread portion 2 includes a first region 11 on one tread end 2t side from the tire equator C, and a second region 12 on the other tread end 2t side from the tire equator C.

  An inner inclined groove 30 and an outer inclined groove 40 are provided in each of the first region 11 and the second region 12 of the tread portion 2. A plurality of inner inclined grooves 30 are provided on the tire equator C side. A plurality of outer inclined grooves 40 are provided on the tread end 2t side.

  The inner inclined groove 30 includes a first inner inclined groove 13 provided in the first region 11 and a second inner inclined groove 23 provided in the second region 12.

A first inner inclined groove 13 and the second inner inclined groove 23, when projected on the tire equator C, and groove ends, with an overlap length L1 in the tire circumferential direction. The overlap length L1 is greater than 0% and less than or equal to 10% of the length A1 of the inner inclined groove 30 in the tire circumferential direction. When the overlap length L1 is 0, or when the first inner inclined groove 13 and the second inner inclined groove 23 are separated in the tire circumferential direction, a rigid step in the tire circumferential direction is likely to occur in the tread portion 2. In particular, the handling stability during braking is reduced. On the contrary, when the overlap length L1 is larger than 10% of the length A1 of the inner inclined groove 30, the rigidity of the crown region Cr is lowered, and the grip performance and the wear resistance performance are lowered.

  The inner inclined groove 30 extends from the inner end 30i in the tire axial direction toward the outer end 30o in the tire axial direction in the direction opposite to the rotational direction R. The inner inclined groove 30 of the present embodiment has a smooth substantially arc shape that is convex toward the tire equator C side. The inner inclined groove 30 extends without intersecting the tire equator C. Such an inner inclined groove 30 maintains the rigidity of the crown region Cr of the tread portion 2 and improves the roll characteristics at the initial stage of the roll.

  The length A1 of the inner inclined groove 30 in the tire circumferential direction is preferably 30% or more, more preferably 35% or more, preferably 50% or less, more preferably 45% or less, of the tread development width TWe. When the length of the inner inclined groove 30 is smaller than 30% of the tread development width TWe, there is a possibility that the wet performance when going straight is lowered. On the contrary, when the length of the inner inclined groove 30 is larger than 50% of the tread development width, the rigidity of the crown region Cr is lowered, and the grip performance and the wear resistance performance during straight travel may be lowered.

  Similarly, the length A2 in the tire axial direction along the tread contact surface of the inner inclined groove 30 is preferably 10% or more, more preferably 13% or more, more preferably 20% or less of the tread deployment width TWe. Preferably it is 17% or less.

  The distance W1 in the tire axial direction along the tread contact surface from the tire equator C to the inner end 30i of the inner inclined groove 30 is preferably 1.5% or more, more preferably 2.5% or more of the tread deployment width TWe. Yes, preferably 5.0% or less, more preferably 4.0% or less. When the distance W1 is smaller than 1.5% of the tread development width TWe, the inner inclined groove 30 is too close to the tire equator C having a large contact pressure, and the wear resistance may be deteriorated. On the other hand, when the distance W1 is larger than 5.0% of the tread development width TWe, there is a risk that the wet performance during straight traveling may be deteriorated.

The distance W2 in the tire axial direction along the tread contact surface from the tire equator C to the outer end 30o of the inner inclined groove 30 is preferably 15% or more, more preferably 18% or more of the tread deployment width TWe, preferably It is 25% or less, more preferably 22% or less. When the distance W2 is smaller than 15% of the tread development width TWe, the rigidity of the crown region Cr in the tire axial direction may be reduced, and as a result, roll characteristics at the initial stage of the roll may be reduced. On the contrary, when the distance W2 is larger than 25 % of the tread development width TWe, the rigidity of the middle region Mi is lowered, and the roll characteristics in the middle of the roll may be lowered.

  The angle θ3 of the inner inclined groove 30 with respect to the tire circumferential direction is preferably 0 to 30 °, more preferably 0 to 20 °. When the angle θ3 of the inner inclined groove 30 with respect to the tire circumferential direction is greater than 30 °, the rigidity of the crown region Cr in the tire circumferential direction may be reduced, and grip performance particularly during acceleration / deceleration may be reduced.

  It is desirable that the angle θ3 of the inner inclined groove 30 with respect to the tire circumferential direction gradually increases from the inner side to the outer side in the tire axial direction. Such an inner inclined groove 30 gradually increases the rigidity in the tire axial direction from the tire equator side C toward the tread end 2t side, and in particular improves the roll characteristics at the initial stage of the roll.

  The maximum groove width W3 of the inner inclined groove 30 is preferably 3.0 mm or more, more preferably 3.5 mm or more, preferably 5.0 mm or less, more preferably 4.5 mm or less. When the groove width W3 of the inner inclined groove 30 is smaller than 3.0 mm, the rigidity of the crown region Cr increases, and the roll characteristics at the initial stage of the roll may be deteriorated. On the contrary, when the groove width W3 of the inner inclined groove 30 is larger than 5.0 mm, the rigidity of the crown region is lowered, and the grip performance and the wear resistance performance may be lowered.

  The inner inclined groove 30 has a groove width W3 that gradually decreases toward the outer side in the tire axial direction. Such an inner inclined groove 30 gradually increases the rigidity of the tread portion 2 from the tire equator C side to the tread end 2t side, suppresses the camber angle from the initial roll stage to the middle roll stage, and further improves the roll characteristics.

  From the same viewpoint, the groove depth d1 (shown in FIG. 1) of the inner inclined groove 30 is preferably 3.0 mm or more, more preferably 3.5 mm or more, preferably 5.0 mm or less, more preferably 4. 5 mm or less.

  The outer inclined groove 40 includes a first outer inclined groove 14 provided in the first region 11 and a second outer inclined groove 24 provided in the second region 12.

A first outer inclined groove 14, and the second outer inclined groove 24, as are distributed in the tire circumferential direction, is provided without overlapping each other when projected on the tire equator C, respectively.

  The outer inclined groove 40 extends from the inner end 40 i in the tire axial direction toward the outer end 40 o in the tire axial direction in the rotational direction R. In this embodiment, the outer inclined groove 40 has a smooth substantially circular arc shape convex toward the rotation direction R side.

  In each of the first region 11 and the second region 12, the inner inclined grooves 30 and the outer inclined grooves 40 are provided alternately in the tire circumferential direction. In each of the first region 11 and the second region 12, the outer inclined groove 40 does not overlap with the adjacent inner inclined groove 30 in the tire circumferential direction when projected in the tire axial direction. Such a tread pattern suppresses a decrease in rigidity in the tire axial direction of the Mi region, suppresses the camber angle, and improves the roll characteristics from the middle of the roll to the end of the roll.

  The distance L2 in the tire circumferential direction between the outer end 40o of the outer inclined groove 40 in the tire axial direction and the outer end 30o of the inner inclined groove 30 is preferably 5% or more, more preferably 10% or more of the tread deployment width TWe. Yes, preferably 30% or less, more preferably 20% or less. When the separation distance L2 is smaller than 5% of the tread development width TWe, the rigidity of the middle region Mi may be reduced, and roll characteristics may be deteriorated. On the other hand, when the separation distance L2 is larger than 30% of the tread development width TWe, the rigidity of the middle region Mi is increased, and it is difficult to provide a camber angle in the middle stage of the roll, and roll characteristics may be deteriorated.

  A length B1 of the outer inclined groove 40 in the tire circumferential direction is smaller than a length A1 of the inner inclined groove 30 in the tire circumferential direction. Further, the length B2 in the tire axial direction along the tread contact surface of the outer inclined groove 40 is larger than the length A2 in the tire axial direction along the tread contact surface of the inner inclined groove 30. In the motorcycle tire 1 provided with the outer inclined groove 40 and the inner inclined groove 30, the rigidity in the tire axial direction of the shoulder region Sh is larger than the rigidity in the tire axial direction of the crown region Cr. For this reason, it is easy to give a camber angle at the initial stage of the roll and to obtain a tire in which the camber angle can be easily suppressed at the end stage of the roll. That is, a tire having excellent roll characteristics can be obtained.

  The length B1 of the outer inclined groove 40 in the tire circumferential direction is preferably 32% or more, more preferably 37% or more, and preferably 52% or less, more preferably the length A1 of the inner inclined groove 30 in the tire circumferential direction. Is 47% or less. When the length B1 of the outer inclined groove 40 is smaller than 32% of the length A1 of the inner inclined groove 30, the difference in rigidity between the crown region Cr and the middle region Mi increases, and roll characteristics from the initial roll stage to the middle roll stage are increased. May decrease. Conversely, when the length B1 of the outer inclined groove 40 is 52% or more of the length A1 of the inner inclined groove 30, the rigidity in the tire axial direction in the shoulder region Sh and the middle region Mi decreases, There is a possibility that the roll characteristics from the middle to the end of the roll may deteriorate.

  The length B2 in the tire axial direction along the tread contact surface of the outer inclined groove 40 is preferably 1.08 times or more, more preferably, the length A2 in the tire axial direction along the tread contact surface of the inner inclined groove 30. 1.10 times or more, preferably 1.16 times or less, more preferably 1.14 times or less. If the length B2 of the outer inclined groove 40 is smaller than 1.08 times the length A2 of the inner inclined groove 30, the rigidity step in the shoulder region Sh is increased, and the roll characteristics at the end of the roll may be deteriorated. is there. On the other hand, when the length B2 of the outer inclined groove 40 is 1.16 times or more the length A2 of the inner inclined groove 30, the roll angle becomes difficult to be suppressed in the middle stage and the end stage of the roll, and the roll characteristics are deteriorated. There is a risk.

Each first outer inclined groove 14 is provided without protruding from the projection area P2 projected in the tire axial direction of each second inner inclined groove 23. The distance D1 in the tire circumferential direction between the outer end 14o of the first outer inclined groove 14 and the inner end 23i of the second inner inclined groove 23, and the outside of the inner end 14i of the first outer inclined groove 14 and the second inner inclined groove 23. The distance D2 in the tire circumferential direction with respect to the end 23o is a length (A1-B1) that is a difference between the tire circumferential direction length A1 of the inner inclined groove 30 and the tire circumferential direction length B1 of the outer inclined groove 40. 30 to 70%.

Similarly, each second outer inclined groove 24 is provided without protruding from the projection region P1 projected in the tire axial direction of each first inner inclined groove 13. The distance D1 in the tire circumferential direction between the outer end 24o of the second outer inclined groove 24 and the inner end 13i of the first inner inclined groove 13, and the outside of the inner end 24i of the second outer inclined groove 24 and the first inner inclined groove 13 The distance D2 in the tire circumferential direction with respect to the end 13o is a length (A1-B1) that is the difference between the tire circumferential direction length A1 of the inner inclined groove 30 and the tire circumferential direction length B1 of the outer inclined groove 40. 30 to 70%.

  The inner inclined groove 30 and the outer inclined groove 40 provide the tread portion 2 with a smooth rigidity distribution from the crown region Cr to the shoulder region Sh, and improve the roll characteristics. Further, such a tread portion 2 has a large rigidity in the vicinity of the middle region Mi and the shoulder region Sh. For this reason, a tire in which the camber angle is easily suppressed at the end of the roll can be obtained.

When the distance D1 and the distance D2 are outside the range of 30 to 70% of the length (A1-B1), the position of the outer inclined groove 40 with respect to the inner inclined groove 30 is biased in the tire circumferential direction. For this reason, a large rigidity difference is generated between the crown region Cr and the middle region Mi, and roll characteristics may be deteriorated. That is, it is desirable that the outer inclined groove 40 be located at the center in the tire circumferential direction in each projection region P1 or P2. From this point of view, the distance D 1 and the distance D2 is preferably the length (A1-B1) of 40% or more, more or preferably 45% or more, preferably 60% or less, more preferably 55% It is as follows.

  The distance W5 in the tire axial direction along the tread contact surface from the tire equator C to the inner end 40i of the outer inclined groove 40 is preferably 15% or more, more preferably 18% or more of the tread deployment width TWe, preferably It is 25% or less, more preferably 18% or less. When the distance W5 is smaller than 15% of the tread development width TWe, the wear resistance performance may be reduced. On the contrary, when the distance W5 is larger than 25% of the tread development width TWe, a large rigidity difference is generated between the crown region Cr and the middle region, and roll characteristics may be deteriorated.

In each of the first region 11 and the second region 12, the distance W6 in the tire axial direction along the tread contact surface between the inner end 40i of the outer inclined groove 40 and the outer end 30o of the inner inclined groove 30 is preferably a tread deployment width. It is 0% or more of TWe, more preferably 3% or more, preferably 10% or less, more preferably 7% or less. When the outer inclined groove 40 and the inner inclined groove 30 overlap when projected in the tire circumferential direction, the rigidity is partially reduced in the middle region Mi, and roll characteristics may be deteriorated. Further, when the distance W6 is larger than 10% of the tread development width TWe, a large rigidity difference is generated between the crown region Cr and the middle region, and roll characteristics may be deteriorated.

  The distance W7 in the tire axial direction along the tread contact surface from the tire equator C to the outer end 40o of the outer inclined groove 40 is preferably 32.5% or more, more preferably 35.0% or more of the tread deployment width TWe. Yes, preferably 42.5% or less, more preferably 40.0% or less. When the distance W7 is smaller than 32.5% of the tread development width TWe, there is a large difference in rigidity between the middle region and the shoulder region, and roll characteristics at the end of the roll may be deteriorated. On the contrary, when the distance W7 is larger than 42.5% of the tread development width TWe, the rigidity of the shoulder region Sh is lowered, and the turning performance may be lowered.

  The angle θ4 of the outer inclined groove 40 with respect to the tire circumferential direction is preferably 30 to 90 °, more preferably 45 to 90 °, in order to sufficiently exhibit the above-described functions.

  It is desirable that the angle θ4 of the outer inclined groove 40 with respect to the tire circumferential direction gradually increases from the inner side to the outer side in the tire axial direction. Such an outer inclined groove 40 gradually increases the rigidity in the tire axial direction from the tire equator side C toward the tread end 2t side, and further improves the roll characteristics from the middle of the roll to the end of the roll.

  The maximum groove width W4 of the outer inclined groove 40 is preferably 3.0 mm or more, more preferably 3.5 mm or more, preferably 5.0 mm or less, more preferably 4.5 mm or less. When the groove width W4 of the outer inclined groove 40 is smaller than 3.0 mm, the wet performance during turning may be deteriorated. On the contrary, when the groove width W4 of the outer inclined groove 40 is larger than 5.0 mm, the rigidity of the shoulder region Sh is lowered, and the grip performance and the wear resistance performance may be lowered.

  The outer inclined groove 40 has a groove width W4 that gradually decreases toward the outer side in the tire axial direction. Such an inner inclined groove 30 suppresses the camber angle from the middle of the roll to the end of the roll, and further improves the roll characteristics.

  From the same viewpoint, the groove depth d2 (shown in FIG. 1) of the outer inclined groove 40 is preferably 3.0 mm or more, more preferably 3.5 mm or more, preferably 5.0 mm or less, more preferably 4. 5 mm or less.

With the above-described tread pattern, in the tire 1 of the present embodiment, the land ratio Lc of the crown region Cr, the land ratio Lm of the middle region Mi, and the land ratio Ls of the shoulder region satisfy the following relationship. Is desirable.
Lc <Ls
Lc ≦ Lm ≦ Ls

  In the tread portion 2 having such a land ratio, the rigidity from the crown region Cr to the shoulder region Sh becomes appropriate, and the roll characteristics from the roll initial stage to the roll final stage are improved.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

A tire for a front wheel for a motorcycle having the basic structure of FIG. 1 and the tread pattern of FIG. 2 was prototyped based on the specifications of Table 1. Further, as Comparative Example 1, a tire having a tread pattern in which the first outer inclined groove and the second inclined groove protrude from the projected area P2 of the second inner inclined groove and the projected area P1 of the first inner inclined groove, respectively, is a prototype. It was done. Each tire was tested for roll characteristics, grip performance and wear resistance. Common specifications and vehicles used for each tire are as follows.
Tire size: 120 / 70ZR17
Rim size: MT3.50 × 17
Internal pressure: 170 kPa
Vehicle used: Motorcycle with a displacement of 600cc
The test method is as follows.

<Roll characteristics, grip performance>
Roll characteristics and grip performance when running on a circuit course with a vehicle equipped with each test tire were evaluated by the driver's sensory evaluation. A result is a score which sets comparative example 1 to 50 points, and shows that roll characteristics and grip performance are excellent, so that a numerical value is large.

<Abrasion resistance>
The amount of wear on the test tire after a certain distance on the circuit course was measured. The result is the reciprocal of the amount of tire wear, and is displayed as an index with the value of Comparative Example 1 being 50. The larger the value, the better the wear resistance.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the roll characteristics of the motorcycle tire of the example were improved without deteriorating grip performance and wear resistance performance.

DESCRIPTION OF SYMBOLS 1 Tire 2 Tread part 11 1st area | region 12 2nd area | region 13 1st inner side inclined groove 14 1st outer side inclined groove 23 2nd inner side inclined groove 24 2nd outer side inclined groove 30 Inner side inclined groove 40 Outer side inclined groove

Claims (8)

A tire for a motorcycle having a tread portion in which a tread pattern in which a rotation direction is specified is formed,
In the developed view showing the tread pattern of the tread portion,
The tread portion includes a first region on one tread end side from the tire equator, and a second region on the other tread end side from the tire equator,
In each of the first region and the second region,
A plurality of inner inclined grooves provided on the tire equator side, and a plurality of outer inclined grooves provided on the tread end side;
The inner inclined groove includes a first inner inclined groove provided in the first region and a second inner inclined groove provided in the second region,
Each of the first inner inclined groove and the second inner inclined groove extends from the inner end in the tire axial direction toward the outer end in the tire axial direction toward the direction opposite to the rotational direction,
The outer inclined groove includes a first outer inclined groove provided in the first region and a second outer inclined groove provided in the second region,
Each of the first outer inclined groove and the second outer inclined groove extends from the inner end in the tire axial direction toward the outer end in the tire axial direction toward the rotational direction,
In each of the first region and the second region, a length B1 of the outer inclined groove in the tire circumferential direction is smaller than a length A1 of the inner inclined groove in the tire circumferential direction, and the outer inclined groove A tire axial length B2 along the tread contact surface is greater than a tire axial length A2 along the tread contact surface of the inner inclined groove,
Said first inner inclined groove, said a second inner inclined groove, when projected onto the road tires red, the groove ends, larger and than 0% tire circumferential direction of the length of the inner inclined groove 10 % Or less in the tire circumferential direction,
Said first outer inclined groove, said a second outer inclined grooves provided without overlapping each other when projected on the tire equator, respectively,
In each of the first region and the second region, the inner inclined groove and the outer inclined groove are alternately provided in the tire circumferential direction, and the outer inclined groove is projected in the tire axial direction. In addition, it does not overlap with the inner inclined groove,
Each of the first outer inclined grooves is provided without protruding from the projection region P2 projected in the tire axial direction of each of the second inner inclined grooves, and the outer end of the first outer inclined groove and the second inner inclined groove The distance D1 in the tire circumferential direction from the inner end of the inclined groove and the distance D2 in the tire circumferential direction between the inner end of the first outer inclined groove and the outer end of the second inner inclined groove are the length. 30-70% of (A1-B1),
Each of the second outer inclined grooves is provided without protruding from the projection area P1 projected in the tire axial direction of each of the first inner inclined grooves, and the outer end of the second outer inclined groove and the first inner groove The distance D1 in the tire circumferential direction from the inner end of the inclined groove and the distance D2 in the tire circumferential direction between the inner end of the second outer inclined groove and the outer end of the first inner inclined groove are the length. A motorcycle tire characterized by being 30 to 70% of the height (A1-B1).
The tread portion includes a crown region that is a region of 40% of the tread deployment width centered on the tire equator, a shoulder region that is a region of 20% of the tread deployment width from each tread end toward the tire equator, and the crown A middle region between the region and the shoulder region,
The motorcycle tire according to claim 1, wherein a land ratio Lc of the crown region, a land ratio Lm of the middle region, and a land ratio Ls of the shoulder region satisfy the following relationship.
Lc <Ls
Lc ≦ Lm ≦ Ls The inner end of each inner inclined groove is located in a range of 1.5 to 5% of the tread development width from the tire equator,
The motorcycle tire according to claim 1 or 2, wherein the outer end of each inner inclined groove is located in a range of 15 to 25% of a tread developed width from the tire equator. Each of the inner inclined grooves has an angle with respect to the tire circumferential direction of 0 to 30 °,
The motorcycle tire according to any one of claims 1 to 3, wherein the angle gradually increases toward an outer side in a tire axial direction.   The motorcycle tire according to any one of claims 1 to 4, wherein each of the inner inclined grooves has a groove width that gradually decreases toward the outer side in the tire axial direction. The inner end of each outer inclined groove is located in a range of 15 to 25% of the tread deployment width from the tire equator,
The motorcycle tire according to any one of claims 1 to 5, wherein the outer end of each outer inclined groove is located in a range of 32.5 to 42.5% of a tread developed width from the tire equator. Each of the outer inclined grooves has an angle with respect to the tire circumferential direction of 30 to 90 °,
The motorcycle tire according to any one of claims 1 to 6, wherein the angle gradually increases toward an outer side in a tire axial direction.   The motorcycle tire according to any one of claims 1 to 7, wherein each of the outer inclined grooves has a groove width that gradually decreases toward the outer side in the tire axial direction.

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