JP2009035228A - Tire for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire 2 for a motorcycle, not impairing stability in transferring from linear advancement to turning, and excellent in various performance. <P>SOLUTION: The tire 2 is provided with a tread 4; and a carcass 12 having a radial structure. The tread 4 includes a central area 22; and a pair of shoulder areas 24 positioned at an outer side in an axial direction than the central area 22. Materials of the central area 22 and the shoulder area 24 are different from each other. A ratio (Wc/Wt) of semi-perimeter Wc of the central area 22 relative to semi-perimeter Wt of the tread 4 is 0.7-0.9, and a ratio (Ws/Wt) of perimeter Ws of the shoulder area 24 relative to semi-perimeter Wt of the tread 4 is 0.1-0.3. A tread division angle θ of the central area 22 and the shoulder area 24 is 15-75°. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic tire mounted on a motorcycle. In particular, the present invention relates to improvements in tire treads.

When the motorcycle turns, centrifugal force acts on the motorcycle. For cornering, a cornering force that balances this centrifugal force is required. When turning, the rider tilts the motorcycle inward. Turning is achieved by the camber thrust generated by this inclination. For the purpose of easy turning, motorcycle tires have a tread with a small radius of curvature. When going straight, the center area of the tread is grounded. On the other hand, when turning, the shoulder region is grounded. Tires in which the roles of the center region and the shoulder region are taken into account are disclosed in Japanese Unexamined Patent Application Publication Nos. 2005-271760 and 2007-131112. Such a tire is excellent in various performances.
JP-A-2005-271760 JP 2007-131112 A

  In a tire for a motorcycle, the center region is mainly grounded when going straight, and the shoulder region is mainly grounded when turning. When shifting from straight travel to turning, the contact surface of the tire tread shifts from the center region to the shoulder region. Tires with different materials for the center and shoulder regions tend to give the rider a feeling of strangeness when turning. Such tires lack stability when moving from straight to turning.

  In order not to impair the stability at the time of transition from straight running to turning, the material of the center region and the shoulder region cannot be greatly different. The stability at the time of transition has been a limitation in the selection of the material of the center region where straight running stability is required and the material of the shoulder region where turning stability is required.

  An object of the present invention is to provide a motorcycle tire excellent in various performances without impairing stability at the time of transition from straight running to turning.

  A motorcycle tire according to the present invention includes a tread and a carcass having a radial structure. The tread includes a center region and a pair of shoulder regions located on the outer side in the axial direction than the center region. The center region and the shoulder region are different in material. The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 or more and 0.9 or less, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less. The tread division angle at the interface between the center region and the shoulder region is not less than 15 ° and not more than 75 °.

  Preferably, in this tire, the hardness of the center region is different from the hardness of the shoulder region. Preferably, the hardness Hc of the center region is larger than the hardness Hs of the shoulder region, and the tire is attached to the rear wheel of the motorcycle. Preferably, the hardness Hc of the center region is smaller than the hardness Hs of the shoulder region, and the tire is attached to the front wheel of the motorcycle.

In the tire, it is preferable that the complex elastic modulus of the center region E ^* is different from a complex elastic modulus of the shoulder region E ^*. Preferably, the complex elastic modulus of the center region E ^* greater than the complex elastic modulus E ^* of the shoulder region, the tire is mounted on Riahoiru. Preferably, the complex elastic modulus of the center region E ^* less than the complex elastic modulus E ^* of the shoulder region, the tire is mounted on the front wheel.

Preferably, the motorcycle tire pair according to the present invention includes the following rear tire (1) and front tire (2).
(1) The rear tire includes a tread and a carcass having a radial structure. The tread includes a center region and a pair of shoulder regions located on the outer side in the axial direction than the center region. The hardness Hc of the center region is larger than the hardness Hs of the shoulder region. The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 or more and 0.9 or less, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less. The tread division angle at the boundary between the center region and the shoulder region is not less than 15 ° and not more than 75 °.
(2) The front tire includes a tread and a carcass having a radial structure. The tread includes a center region and a pair of shoulder regions located on the outer side in the axial direction than the center region. The hardness Hc of the center region is smaller than the hardness Hs of the shoulder region. The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 or more and 0.9 or less, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less. The tread division angle at the boundary between the center region and the shoulder region is not less than 15 ° and not more than 75 °.

  In a motorcycle tire, when shifting from straight travel to turning, the contact surface of the tire tread gradually shifts from the center region to the shoulder region. Although the tire according to the present invention is a tire in which the material of the center region and the shoulder region are different, the uncomfortable feeling given to the rider during turning is reduced. This tire is excellent in stability during the transition from straight to turning. In this tire, the discomfort of the rider is reduced, so that the center region and the shoulder region can be made of a material suitable for each role. With this tire, excellent performances can be achieved.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a cross-sectional view showing a tire 2 according to an embodiment of the present invention. In FIG. 1, the vertical direction is the radial direction, and the horizontal direction is the axial direction. The tire 2 has a substantially bilaterally symmetric shape with the one-dot chain line CL as the center. This alternate long and short dash line represents the equator plane. The tire 2 includes a tread 4, a wing 6, a sidewall 8, a bead 10, a carcass 12, a belt 14, an inner liner 16, and a chafer 18. The tire 2 is a tubeless type pneumatic tire. The tire 2 is attached to a motorcycle.

  The tread 4 has a shape protruding outward in the radial direction. The tread 4 forms a tread surface 20 that contacts the road surface. The tread 4 includes one center region 22 and a pair of shoulder regions 24. The center region 22 straddles the equator plane CL. The shoulder region 24 is located outside the center region 22 in the axial direction.

  The sidewall 8 extends substantially inward in the radial direction from the end of the tread 4. The sidewall 8 is made of a crosslinked rubber composition. The sidewall 8 absorbs an impact from the road surface by bending. Further, the sidewall 8 prevents the carcass 12 from being damaged.

  The bead 10 extends from the sidewall 8 substantially inward in the radial direction. The bead 10 includes a core 26 and an apex 28 that extends radially outward from the core 26. The apex 28 is tapered outward in the radial direction. The apex 28 is made of a crosslinked rubber composition. The apex 28 has a high hardness.

  The carcass 12 includes a ply 30. The ply 30 extends along the inner surfaces of the tread 4 and the sidewall 88. The ply 30 is folded around the core 26 from the inner side to the outer side in the axial direction. By this folding, the main portion 34 and the folding portion 36 are formed in the ply 30. The folded portion 36 is laminated on the outer surface of the main portion 34.

  Although not shown, the ply 30 is composed of a cord and a topping rubber. The absolute value of the angle formed by the cord with respect to the equator plane CL is 65 ° to 90 °. In other words, the tire 2 has a radial structure. The cord is made of organic fiber. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The belt 14 is located between the carcass 12 and the tread 4. The belt 14 includes a belt ply 40. Although not shown, the belt ply 40 is composed of a cord and a topping rubber. The cord extends substantially in the circumferential direction and is wound spirally. The belt 14 has a so-called jointless structure. This belt 14 suppresses kickback and shimmy. The tire 2 provided with the belt 14 is excellent in disturbance absorbing performance.

  The material of the cord of the belt 14 is steel or organic fiber. Specific examples of the organic fiber include aramid fiber, nylon fiber, polyester fiber, rayon fiber, and polyethylene naphthalate fiber. From the viewpoint of high restraining force and thus high rigidity, the preferred material of the cord is steel or aramid fiber. In particular, steel is preferred.

  The inner liner 16 is joined to the inner peripheral surface of the carcass 12. The inner liner 16 is made of a crosslinked rubber. For the inner liner 16, rubber having excellent air shielding properties is used. The inner liner 16 serves to maintain the internal pressure of the tire 2.

  What is indicated by a point P in FIG. 1 is an intersection where the interface between the center region 22 and the shoulder region 24 intersects the tread surface 20 in the cross section of this figure. In FIG. 1, what is indicated by a double arrow Wt is the half circumference of the tread 4. The half circumference Wt is a distance from the equator CL to the tread end, measured along the tread surface 20. What is indicated by a double-headed arrow Wc is the half circumference of the center region 22. The half circumference Wc is a distance from the equator CL to the end point P of the center region 22 measured along the tread surface 20. What is indicated by a double arrow Ws is the circumference of the shoulder region 24. The circumferential length Ws is a distance from the point P at one end of the shoulder region 24 to the other end measured along the tread surface 20. The circumferential lengths Wt, Wc and Ws are measured in a sample obtained by cutting the tire 2.

  The center region 22 and the shoulder region 24 are each made of a crosslinked rubber composition. The material of the center region 22 and the material of the shoulder region 24 are different. In the tire 2, the center region 22 is mainly grounded when going straight. In the tire 2, the shoulder region 24 is mainly grounded when turning. The center region 22 is required to have straight running stability and wear resistance. The shoulder region 24 is required to have turning stability and turning performance. In the tire 2, the respective materials are determined in consideration of the roles of the center region 22 and the shoulder region 24.

  At the time of turning, the contact surface of the tread 4 of the tire 2 moves from the center region 22 to the shoulder region 24. In a tire having a boundary between the center region 22 and the shoulder region 24 in a frequently used region of the tread surface 20, the rider tends to feel uncomfortable when turning. In this respect, the ratio (Wc / Wt) is preferably equal to or greater than 0.7. During turning, the tire is required to have turning stability and turning performance. A material suitable for turning stability and turning performance is used for the shoulder region 24. In this respect, the ratio (Wc / Wt) between the center region 22 and the shoulder region 24 is preferably 0.9 or less, and more preferably 0.8 or less.

  From the viewpoint of turning stability and turning performance during turning, the ratio (Ws / Wt) is preferably equal to or greater than 0.1, and more preferably equal to or greater than 0.2. When traveling straight, the tire 2 is required to have straight running stability and wear resistance during straight running. The center region 22 is made of a material suitable for straight running stability and wear resistance. The ratio (Ws / Wt) is preferably equal to or less than 0.3 from the viewpoint of stability at the time of transition from straight travel to turning.

  In the cross section of FIG. 1, a point Q indicates an intersection where the interface between the center region 22 and the shoulder region 24 intersects the inner surface of the tread 4. What is indicated by a straight line L1 is a normal line of the tread surface 20 at the point P. What is indicated by the straight line L2 is a straight line passing through the points P and Q. What is indicated by the angle θ is an angle formed by the straight line L1 and the straight line L2. This angle θ is a tread division angle between the center region 22 and the shoulder region 24. In FIG. 1, the angle θ is shown as positive from the straight line L1 in the clockwise direction and negative in the counterclockwise direction. The tire 2 has a symmetrical shape with respect to the straight line CL. In the opposite cross section, not shown in FIG. 1, this angle θ is shown with the counterclockwise direction being positive and the clockwise direction being negative. In the cross section of FIG. 1, the interface between the center region 22 and the shoulder region 24 is indicated by a straight line. This interface is not necessarily limited to a straight line. Even if the interface is non-linear, the angle θ formed by the straight line L1 and the straight line L2 is the tread division angle. The straight line L1, the straight line L2, and the angle θ are measured in a sample obtained by cutting the tire 2.

  The angle θ of the tire 2 is not less than 15 ° and not more than 75 °. The tread 4 receives a shearing force at the time of transition from straight traveling to turning traveling. In the tire 2 having an angle θ of less than 0 °, a shearing force acts in a direction in which the shoulder region 24 is easily peeled off at the interface between the center region 22 and the shoulder region 24. In the tire 2 having the angle θ of 0 ° or more and less than 15 °, the characteristics of the tire 2 change abruptly at the time of transition from straight running to turning, and the rider tends to feel uncomfortable. In the tire 2 having the angle θ of 15 ° or more, the center region 22 is positioned on the outer surface side of the shoulder region 24 at the interface between the center region 22 and the shoulder region 24. In the tire 2, the characteristics of the tire 2 gradually change during the transition from the straight traveling to the turning traveling, and the discomfort of the rider is reduced. The tire 2 is excellent in stability at the time of transition from straight running to turning. Even if the tire 2 changes the material of the center region 22 and the shoulder region 24, the discomfort experienced by the rider is reduced. In the tire 2 according to the present invention, there are few restrictions when the center region 22 and the shoulder region 24 are made of different materials. In the tire 2, the shoulder region 24 is not easily peeled off during the transition from the straight traveling to the turning traveling. From these viewpoints, the angle θ is preferably 30 ° or more, and more preferably 40 ° or more.

  The tire 2 having a large angle θ is difficult to manufacture. From this viewpoint, the angle θ is set to 75 ° or less. Preferably it is 60 degrees or less, More preferably, it is 50 degrees or less.

The present invention can be applied to various tires 2 having different materials for the center region 22 and the shoulder region 24. The present invention can be applied to the tire 2 in which the hardness of the center region 22 is larger than the hardness of the shoulder region 24 and the tire 2 in which the hardness of the center region 22 is smaller than the hardness of the shoulder region 24. The present invention, complex elastic modulus E ^* is less than the tire of the complex elastic modulus E ^* is the shoulder region 24 of the complex elastic modulus E ^* is larger than the tire 2 and the center region 22 of the complex elastic modulus E ^* is the shoulder region 24 of the center region 22 2 is applicable. The present invention can be applied to the tire 2 in which the loss tangent tan δ in the center region 22 is larger than the loss tangent tan δ in the shoulder region 24 and the tire 2 in which the loss tangent tan δ in the center region 22 is smaller than the loss tangent tan δ in the shoulder region 24.

  In the tire 2 in which the hardness Hc of the center region 22 is greater than the hardness Hs of the shoulder region 24, the high-hardness center region 22 is mainly grounded when traveling straight. The tire 2 is excellent in straight running stability performance. At the time of turning, the shoulder region 24 having a low hardness is mainly grounded. The shoulder region 24 having a low hardness Hs is excellent in grip performance. The tire 2 is excellent in turning stability performance. From this point of view, the difference (Hc−Hs) between the hardness of the center region 22 and the shoulder region 24 is preferably 2 or more, and more preferably 3 or more. From the viewpoint of stability at the time of transition from straight travel to turning, the difference (Hc−Hs) is preferably 7 or less, and more preferably 6 or less. A motorcycle using the tire 2 as a rear tire is excellent in straight running stability and turning stability.

  In the tire 2, step wear hardly occurs between the center region 22 and the shoulder region 24 even if the difference (Hc−Hs) between the hardness Hs and the hardness Hc is 2 or more. In the tire 2, a tread emphasizing wear resistance can be arranged in the center region 22 and a tread emphasizing grip can be arranged in the shoulder region 24 without being limited by the difference between the hardness Hs and the hardness Hc.

  From the viewpoint of straight running stability, the hardness Hc is preferably 63 or more, and more preferably 65 or more. The hardness Hc is preferably 73 or less. From the viewpoint of grip performance, the hardness Hs is preferably 70 or less, and more preferably 68 or less. The hardness Hs is preferably 60 or more.

  In the tire 2 in which the hardness Hc of the center region 22 is smaller than the hardness Hs of the shoulder region 24, the low-hardness center region 22 is mainly grounded when traveling straight. This tire 2 is excellent in disturbance absorbing performance. When turning, the shoulder region 24 having high hardness is mainly grounded. A large camber thrust is generated in the shoulder region 24 having a high hardness Hs. The tire 2 is excellent in turning performance. From this viewpoint, preferably, the difference (Hc−Hs) between the hardness of the center region 22 and the hardness of the shoulder region 24 is 2 or more, and more preferably 3 or more. From the viewpoint of stability at the time of transition from straight travel to turning, the difference (Hc−Hs) is preferably 7 or less, and more preferably 6 or less. The motorcycle with the tire 2 attached to the front tire is excellent in disturbance absorbing performance and turning performance.

  From the viewpoint of disturbance absorbing performance, the hardness Hc is preferably 70 or less, and more preferably 68 or less. The hardness Hc is preferably 58 or higher. From the viewpoint of turning performance, the hardness Hs is preferably 60 or more, and more preferably 63 or more. The hardness Hs is preferably 73 or less.

The complex elastic modulus E ^* is larger than the tire 2 of the complex elastic modulus E ^* is the shoulder region 24 of the center region 22, high wear resistance by the complex elastic modulus E ^* is larger center region 22 is obtained. The tire 2 is excellent in straight running stability performance. In the tire 2, a high grip performance is obtained by the shoulder region 24 having a small complex elastic modulus E ^* . The tire 2 is excellent in turning performance. A motorcycle in which the tire 2 is mounted on a rear tire is excellent in straight running stability performance and turning performance.

The complex elastic modulus E ^* is less than the tire 2 complex elastic modulus E ^* of the shoulder region 24 of the center region 22, high disturbance absorbing performance by the complex elastic modulus E ^* is less center region 22 is obtained. In the tire 2, a large camber thrust is generated by the shoulder region 24 having a large complex elastic modulus E ^* . The motorcycle with the tire 2 attached to the front tire is excellent in disturbance absorbing performance and turning performance. Even if the tire 2 according to the present invention uses a material suitable for each role, the uncomfortable feeling given to the rider is reduced.

  The tire pair according to the present invention is a rear tire according to the present invention in which the hardness Hc of the center region 22 is larger than the hardness Hs of the shoulder region 24 and the present invention in which the hardness Hc of the center region 22 is smaller than the hardness Hs of the shoulder region 24. It consists of such a front tire. A motorcycle equipped with this tire pair has excellent turning maneuvering stability. In this motorcycle, when traveling straight, disturbance absorption performance is exhibited by the front tire, and stability performance is exhibited by the rear tire. When turning, a large camber thrust is generated by the front tire, and excellent grip performance is exhibited by the rear tire. This tire pair is excellent in various performances.

  Hardness Hc and Hs are JIS-A hardness. The hardnesses Hc and Hs are measured by pressing a type A durometer against the tire 2 in an environment of 23 ° C. in accordance with the rules of “JIS-K 6253”.

The complex elastic modulus E ^* and the loss tangent tan δ are measured by a viscoelastic spectrometer (trade name “VA-200”, manufactured by Shimadzu Corporation) under the conditions shown below in accordance with the provisions of “JIS-K 6394”. Is done.
Initial strain: 10%
Amplitude: ± 2%
Frequency: 10Hz
Deformation mode: Tensile Measurement temperature: 70 ° C

  FIG. 2 is a cross-sectional view for explaining a manufacturing process of the tire 2 of FIG. In the manufacture of the tire 2, the inner liner 16 and the first ply 30 are sequentially wound around a former (not shown). On this first ply 30, a ribbon 46 composed of a cord 42 and a topping rubber 44 is spirally wound to form a belt ply 40 having a jointless structure. The ribbon 46 extends substantially in the circumferential direction. A first strip 48 made of uncrosslinked rubber is wound on the belt ply 40 in a spiral shape. The first strip 48 extends substantially in the circumferential direction. The first strips 48 are sequentially stacked. When the first strip 48 has been wound, the second strip 50 made of uncrosslinked rubber is wound continuously with the first strip 48. The second strip 50 extends substantially in the circumferential direction. The second strips 50 are sequentially stacked. When the second strip 50 has been wound, the first strip 48 is further wound continuously with the second strip 50. A green tire is thus obtained. This green tire is put into a mold, and pressurized and heated. A cross-linking reaction occurs in the rubber by heating, and the tire 2 is obtained. A shoulder region 24 is obtained from the first strip 48. A center region 22 is obtained from the second strip 50. In the tire 2, since two kinds of strips 48 and 50 are used, the tread 4 including the center region 22 and the shoulder region 24 is easily formed. The tire 2 is easy to manufacture.

  In the present invention, unless otherwise specified, the size and angle of each member of the tire 2 are measured in a state where the tire 2 is incorporated in a regular rim and the tire 2 is filled with air so as to have a regular internal pressure. At the time of measurement, no load is applied to the tire 2. In the present specification, the normal rim means a rim defined in a standard on which the tire 2 depends. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In the present specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 2 relies. “Maximum air pressure” in the JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in the TRA standard, and “INFLATION PRESSURE” in the ETRTO standard are normal internal pressures.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Experiment 1]
A front tire of Example 1 having the structure shown in FIG. 1 was obtained. The belt of the front tire has a cord made of steel. The tread of the front tire includes a center region and a pair of shoulder regions. The hardness Hc of the center region is 62, and the hardness Hs of the shoulder region is 65. In this front tire, the ratio (Wc / Wt) is 0.75, and the ratio (Ws / Wt) is 0.25. The size of the front tire is “120 / 70ZR17”.

[Examples 2 and 3 and Comparative Examples 1 and 2]
The tires of Examples 2 and 3 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 except that the ratio (Wc / Wt) and the ratio (Ws / Wt) of the front tire were as shown in Table 1. It was.

[Examples 4 and 5 and Comparative Examples 3 and 4]
Tires of Examples 4 and 5 and Comparative Examples 3 and 4 were obtained in the same manner as Example 1 except that the tread division angle θ of the front tire was changed as shown in Table 1.

[Example 6]
A tire of Example 6 was obtained in the same manner as in Example 1 except that the hardness Hs of the shoulder region of the front tire was as shown in Table 1.

[Comparative Examples 5 and 6]
Tires of Comparative Examples 5 and 6 were obtained in the same manner as in Example 1 except that a tread composed of a single member having the tread hardness of the front tire as shown in Table 1 was formed.

[Running stability evaluation]
A prototype tire was mounted on the front wheel of a commercial motorcycle with a displacement of 1000 cc. The rim width was 3.5 inches and the tire internal pressure was 250 kPa. As the rear wheel tire, a commercially available conventional tire was used as it was. The motorcycle was run on a circuit course, and the rider was given a sensory evaluation regarding straight-line stability, turning stability, and stability during the transition from straight to turning. The results are shown in Table 1 below. Larger values indicate better results.

[An endurance test]
Durability tests were performed on the tires of Examples 1 to 6 and Comparative Examples 1 to 6. In the durability test, a continuous turning test was performed on an actual vehicle, and the appearance of the interface portion was observed. Relative evaluation was performed by observing whether or not even a slight wrinkle or the like was observed at the interface portion. The results are shown in Table 1 below. In this evaluation, three-stage relative evaluation of ABC was performed. In this evaluation, A is the best evaluation.

[Experiment 2]
A rear tire of Example 7 having the structure shown in FIG. 1 was obtained. The belt of the rear tire has a cord made of steel. The rear tire tread includes a center region and a pair of shoulder regions. The hardness Hc of the center region is 65, and the hardness Hs of the shoulder region is 62. In this rear tire, the ratio (Wc / Wt) is 0.75, and the ratio (Ws / Wt) is 0.25. The size of the rear tire is “190 / 50ZR17”.

[Examples 8 and 9 and Comparative Examples 7 and 8]
Tires of Examples 8 and 9 and Comparative Examples 7 and 8 were obtained in the same manner as Example 7 except that the ratio (Wc / Wt) and ratio (Ws / Wt) of the rear tire were as shown in Table 2. .

[Examples 10 and 11 and Comparative Examples 9 and 10]
Tires of Examples 10 and 11 and Comparative Examples 9 and 10 were obtained in the same manner as Example 7 except that the tread division angle θ of the rear tire was changed as shown in Table 2.

[Example 12]
A tire of Example 12 was obtained in the same manner as Example 7 except that the hardness Hs of the shoulder region of the rear tire was as shown in Table 2.

[Comparative Examples 11 and 12]
Tires of Comparative Examples 11 and 12 were obtained in the same manner as in Example 7, except that a tread composed of a single member having the tread hardness of the rear tire as shown in Table 2 was formed.

[Running stability evaluation]
The prototype tires of Examples 7 to 12 and Comparative Examples 7 to 12 were mounted on the rear wheels of a commercial motorcycle having a displacement of 1000 cc. The rim width was 6.0 inches and the tire air pressure was 290 kPa. The tire of Example 1 was mounted on the front wheel. The motorcycle was run on a circuit course, and the rider was given a sensory evaluation regarding straight-line stability, turning stability, and stability during the transition from straight to turning. The results are shown in Table 2 below. Larger values indicate better results.

[An endurance test]
Durability tests were performed on the tires of Examples 7 to 12 and Comparative Examples 7 to 12 in the same manner as in Experiment 1. The results are shown in Table 2 below.

[Experiment 3]
[Examples 13 and 14 and Comparative Examples 13 to 15]
The rear tires of Examples 13 and 14 and Comparative Examples 13 to 15 were prepared in the same manner as in Example 7 except that the hardness of the center region and the shoulder region, the complex elastic modulus E ^* and the loss tangent tan δ were as shown in Table 3. Obtained.

[Running stability evaluation]
Similar to Experiment 2, a prototype tire was mounted on the rear wheel of a commercial motorcycle having a displacement of 1000 cc. The rim width was 6.0 inches and the tire air pressure was 290 kPa. As the front wheel tire, a commercially available conventional tire was used as it was. The motorcycle was run on a circuit course, and the rider was given a sensory evaluation regarding straight-line stability, turning stability, and stability during the transition from straight to turning. Larger values indicate better results.

  As shown in Tables 1 to 3, the tire pairs of the examples are excellent in various performances. From this evaluation result, the superiority of the present invention is clear.

  The tire according to the present invention can be mounted on various motorcycles.

FIG. 1 is a cross-sectional view illustrating a rear tire according to an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining a manufacturing process of the tire of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Tire 4 ... Tread 8 ... Side wall 10 ... Bead 12 ... Carcass 14 ... Belt 16 ... Inner liner 20 ... Tread surface 22 ... Center area 24 ... Shoulder area 46 ... Ribbon 48 ... First strip 50 ... Second strip

Claims (8)

It has a tread and a carcass having a radial structure,
The tread includes a center region and a pair of shoulder regions positioned outside in the axial direction from the center region,
The material of the center area and shoulder area are different,
The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 or more and 0.9 or less, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less,
A motorcycle tire in which a tread division angle at an interface between the center region and the shoulder region is 15 ° or more and 75 ° or less.   The tire according to claim 1, wherein the hardness of the center region is different from the hardness of the shoulder region.   The tire according to claim 2, wherein a hardness of the center region is larger than a hardness of the shoulder region, and the tire is attached to a rear wheel of the motorcycle.   The tire according to claim 2, wherein the tire is attached to a front wheel of a motorcycle having a hardness in a center region smaller than a hardness in a shoulder region. A tire according to claim 1, the complex elastic modulus of the center region E ^* is different from the complex elastic modulus E ^* of the shoulder area Complex elastic modulus of the center region E ^* is larger than the complex elastic modulus E ^* of the shoulder region, tire according to claim 5 which is mounted on Riahoiru Complex modulus complex elastic modulus E ^* of the shoulder region of the center region E ^* less than, tire according to claim 5 which is mounted on the front wheel (1) It has a tread and a carcass having a radial structure,
The tread includes a center region and a pair of shoulder regions positioned outward in the axial direction from the center region.
The hardness of the center area is larger than the hardness of the shoulder area,
The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 to 0.9, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less,
A rear tire having a tread division angle at a boundary between the center region and the shoulder region of 15 ° or more and 75 ° or less, and (2) a tread, and a carcass having a radial structure,
The tread includes a center region and a pair of shoulder regions positioned outward in the axial direction from the center region.
The hardness of the center area is smaller than the hardness of the shoulder area,
The ratio (Wc / Wt) of the center region half circumference Wc to the tread half circumference Wt is 0.7 to 0.9, and the ratio of the shoulder region circumference Ws to the tread half circumference Wt (Ws / Wt). ) Is 0.1 or more and 0.3 or less,
A pair of motorcycle tires including a front tire having a tread division angle of 15 ° or more and 75 ° or less at a boundary between the center region and a shoulder region.

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