JP5350749B2 - Tires for motorcycles - Google Patents

Description

  The present invention relates to a pair of tires for a motorcycle.

  If the rigidity is adjusted from the viewpoint of improving the maneuverability, the tire ride comfort may be reduced. On the other hand, when the rigidity is adjusted from the viewpoint of improving the riding comfort, the maneuverability of the tire may be reduced. Since maneuverability and riding comfort are in a trade-off relationship, it is difficult to achieve both.

  The radial tire is characterized in that the rigidity of the tread portion and the sidewall portion can be easily controlled as compared with the bias tire. Radial tires are superior to bias tires in terms of both maneuverability and ride comfort.

It has been studied to appropriately control the rigidity of the radial tire to improve the running performance of the two-wheeled vehicle. An example of this study is disclosed in JP-A-6-270613.
Japanese Patent Laid-Open No. 6-270613

  In radial tires with high flatness, the sidewall has a large radial length. In particular, in a tire having a high flatness ratio and a large tread width, there is a concern that the tire rigidity is insufficient. Therefore, the rigidity of the tire is adjusted by arranging the cords included in the carcass so that the angle formed with respect to the equator plane is less than 90 °. Thus, in a tire with ensured rigidity, not only the sidewall portion but also the tread portion rigidity is improved. In such a tire, the maneuverability is improved, but the ride comfort is lowered.

  In a two-wheeled vehicle, a rigidity is required for the front tire during braking, and a rigidity is required for the rear tire during acceleration. In the tire pair, since the rigidity feeling required for each of the front tire and the rear tire is different, it is more difficult to achieve both the rigidity feeling and the riding comfort as the tire pair. With such a tire pair, there is a limit to improving the running performance of a two-wheeled vehicle.

  An object of the present invention is to provide a tire pair having excellent rigidity and riding comfort.

  The two-wheeled vehicle tire pair according to the present invention includes a front radial tire and a rear radial tire. Each of the front radial tire and the rear radial tire has a tread whose outer surface forms a tread surface, a pair of sidewalls that extend substantially inward in the radial direction from the end of the tread, and a radial direction from the sidewall. A pair of beads positioned substantially inside and a pair of reinforcing layers positioned on the inner side in the axial direction of the sidewall are provided. The reinforcing layer includes a cord. In the radial tire for a front, the cord extends from the inner end thereof in a forward rotation direction toward the radially outer side. In the rear radial tire, the cord extends from the inner end thereof to the outer side in the radial direction so as to incline in the direction opposite to the normal rotation direction.

Preferably, in the tire pair, the absolute value of the inclination angle of the cord is 30 ° or more and 60 ° or less in each of the front radial tire and the rear radial tire.

Preferably, in the tire pair, in each of the front radial tire and the rear radial tire, the cord is an organic fiber cord or a steel cord made of nylon fiber, polyester fiber, rayon fiber, aramid fiber, or polyethylene naphthalate fiber. is there.

Preferably, in the tire pair, each of the front radial tire and the rear radial tire further includes a band located on the radially inner side of the tread. The length from the outer end of the reinforcing layer to the end of the band is 20 mm or less. The inner end portion of the reinforcing layer overlaps the bead in the axial direction.

Preferably, in the tire pair, the density of the cord is 25 ends / 5 cm or more and 60 ends / 5 cm or less in each of the front radial tire and the rear radial tire.

Preferably, in the tire pair, the strength of the cord is 200 N or more and 900 N or less in each of the front radial tire and the rear radial tire.

  In the tire pair, a reinforcing layer including a cord is provided on the inner side in the axial direction of the sidewall in each of the front radial tire and the rear radial tire. This reinforcing layer can effectively improve the rigidity of the side wall portion. This reinforcing layer can contribute to maneuverability without impairing the ride comfort. In the front radial tire, the cord included in the reinforcing layer extends from the inner end of the cord toward the radially outer side while inclining in the forward rotation direction. The inclination direction of the cord corresponds to the direction of stress applied to the front radial tire during braking. A front radial tire having this reinforcing layer is excellent in rigidity during braking. This front radial tire can improve the braking stability of a two-wheeled vehicle. In the rear radial tire, the cord included in the reinforcing layer extends from the inner end thereof to the outer side in the radial direction so as to incline in the direction opposite to the normal rotation direction. The inclination direction of the cord corresponds to the direction of stress applied to the rear radial tire during acceleration. The rear radial tire having this reinforcing layer is excellent in a feeling of rigidity during acceleration. This rear radial tire can improve the acceleration performance of a two-wheeled vehicle. Since this tire pair is excellent in rigidity and riding comfort, it can contribute to the improvement of the running performance of a two-wheeled vehicle.

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

  FIG. 1 is a perspective view showing a two-wheeled vehicle 4 equipped with a tire pair 2 according to an embodiment of the present invention. The tire pair 2 includes a front radial tire 6 and a rear radial tire 8. The rotation direction of the tires 6 and 8 when the motorcycle 4 moves forward is the normal rotation direction.

  FIG. 2 is a cross-sectional view showing a part of the front radial tire 6 constituting the tire pair 2 of FIG. In FIG. 2, the vertical direction is the radial direction, the horizontal direction is the axial direction, and the direction perpendicular to the paper surface is the circumferential direction. This circumferential direction is synonymous with the rotation direction. This front radial tire 6 (hereinafter referred to as a front tire) has a substantially bilaterally symmetric shape centered on a one-dot chain line CL in FIG. This alternate long and short dash line CL represents the equator plane of the front tire 6. The front tire 6 includes a tread 10, a sidewall 12, a bead 14, a carcass 16, a band 18, a reinforcing layer 20, an inner liner 22 and a chafer 24. The front tire 6 is a tubeless type.

  The tread 10 is made of a crosslinked rubber having excellent wear resistance. The tread 10 has a shape protruding outward in the radial direction. The tread 10 includes a tread surface 26. The tread surface 26 is in contact with the road surface. In the front tire 6, no groove is cut in the tread surface 26. Grooves may be cut to form a tread pattern.

  The sidewall 12 extends substantially inward in the radial direction from the end of the tread 10. The sidewall 12 is made of a crosslinked rubber. The sidewall 12 absorbs an impact from the road surface by bending. Further, the sidewall 12 prevents the carcass 16 from being damaged.

  The bead 14 is located substantially inward of the sidewall 12 in the radial direction. The bead 14 includes a core 28 and an apex 30 that extends radially outward from the core 28. The core 28 has a ring shape. The core 28 includes a plurality of non-stretchable wires (typically steel wires). The apex 30 is tapered outward in the radial direction. The apex 30 is made of a highly hard crosslinked rubber.

  The carcass 16 includes a carcass ply 32. The carcass ply 32 is bridged between the beads 14 on both sides, and extends along the inside of the tread 10 and the sidewall 12. The carcass ply 32 is folded around the core 28 from the inner side to the outer side in the axial direction.

  Although not shown, the carcass ply 32 includes a large number of cords arranged in parallel and a topping rubber. The absolute value of the angle formed by each cord with respect to the equator plane is usually 70 ° to 90 °. In other words, the carcass 16 has a radial structure. The front tire 6 is superior to a bias tire in which the carcass 16 has a bias structure in terms of both handling characteristics and riding comfort. Note that the absolute value of this angle is preferably 90 ° from the standpoint of effectively achieving both maneuverability and riding comfort.

  The cord of the carcass ply 32 is usually made of an organic fiber. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The band 18 is located on the inner side in the radial direction of the tread 10. The band 18 is located on the outer side in the radial direction of the carcass 16 and is laminated on the carcass 16. The band 18 is located between the carcass 16 and the tread 10. Although not shown, the band 18 is composed of a cord and a topping rubber. The cord extends substantially in the circumferential direction and is wound spirally. The band 18 has a so-called jointless structure. The band 18 can contribute to the rigidity of the front tire 6 in the radial direction. In the front tire 6, the influence of the centrifugal force acting during traveling is suppressed. The front tire 6 is excellent in high speed stability. Examples of the cord include a steel cord whose material is steel and an organic fiber cord made of organic fibers. Examples of the organic fiber include nylon fiber, polyester fiber, rayon fiber, polyethylene naphthalate fiber, and aramid fiber. In the front tire 6, a belt including a cord inclined with respect to the equator plane may be used instead of the band 18, and the belt is disposed between the band 18 and the carcass 16. Also good.

  The reinforcing layer 20 is located on the inner side in the axial direction of the sidewall 12. The reinforcing layer 20 extends along the carcass 16 from the bead 14 portion toward the outside in the radial direction. From the viewpoint of preventing formation of a portion having a specific rigidity, it is preferable that an end 34 (hereinafter referred to as an outer end) located on the radially outer side of the reinforcing layer 20 and an end 36 of the band 18 are close to each other. As shown in the figure, in the front tire 6, the outer end 34 of the reinforcing layer 20 is located in the vicinity of the end 36 of the band 18. More specifically, the outer end 34 is located radially outward from the end 36 of the band 18. In other words, the outer end 34 of the reinforcing layer 20 is covered with the end 36 of the band 18. Note that the outer end 34 may be located radially inward of the end 36 of the band 18. In this case, the reinforcing layer 20 and the band 18 are arranged with an appropriate interval.

  An end 38 (hereinafter referred to as an inner end) located on the radially inner side of the reinforcing layer 20 is located on the radially inner side with respect to the end 40 of the carcass ply 32. The inner end 38 is located in the vicinity of the core 28 of the bead 14. As shown in the drawing, the inner end 38 is located radially outward from the upper surface 42 of the core 28.

  The portion of the inner end 38 of the reinforcing layer 20 overlaps the bead 14 in the axial direction. More specifically, the inner end 38 overlaps the apex 30 of the bead 14 in the axial direction. As shown in the figure, the portion of the inner end 38 is sandwiched between the apex 30 and the carcass ply 32 outside the bead 14 in the axial direction. In other words, the inner end 38 is laminated on the folded carcass ply 32a. The inner end 38 may be sandwiched between the apex 30 and the carcass ply 32b on the inner side in the axial direction of the bead 14.

  FIG. 3 is a schematic view showing the front tire 6 of FIG. FIG. 4 is an enlarged plan view showing a part of FIG. FIG. 4 shows a portion of the inner end 38 of the reinforcing layer 20 of the front tire 6. 3 and 4, the arrow line A represents the forward rotation direction of the front tire 6. The vertical direction of the paper surface is the axial direction. An alternate long and short dash line FL represents the radial direction of the front tire 6.

  In the front tire 6, the reinforcing layer 20 includes a cord 44 and a topping rubber 46. The cord 44 is preferably an organic fiber cord made of nylon fiber, polyester fiber, rayon fiber, aramid fiber or polyethylene naphthalate fiber or a steel cord whose material is steel. In the front tire 6, an appropriate code 44 is selected in consideration of its specifications and the like.

  As described above, in the front tire 6, the reinforcing layer 20 extends along the carcass 16 from the bead 14 portion toward the outside in the radial direction. Therefore, the cord 44 also extends along the carcass 16 from the bead 14 portion toward the outside in the radial direction. As shown, the cord 44 is inclined with respect to the radial direction. In the front tire 6, the reinforcing layer 20 can effectively improve the rigidity of the sidewall 12 portion. The front tire 6 is excellent in maneuverability.

  In the front tire 6, the cord 44 extends from the inner end 48 so as to incline in the forward rotation direction. The inclination direction of the cord 44 corresponds to the direction of stress applied to the front tire 6 during braking. In particular, the reinforcing layer 20 can contribute to the rigidity of the front tire 6 during braking. The front tire 6 is excellent in rigidity. The front tire 6 can improve the braking stability of the two-wheeled vehicle 4.

  In the front tire 6, the reinforcing layer 20 is located in a portion from the vicinity of the end 36 of the band 18 to the vicinity of the core 28 of the bead 14. The reinforcing layer 20 does not hinder the riding comfort of the front tire 6. The front tire 6 is excellent in ride comfort.

  In FIG. 4, the alternate long and short dash line FC represents the center line of the cord 44. A solid line FB is a straight line perpendicularly intersecting with the one-dot chain line FL at the inner end 48 of the cord 44. The angle α represents an angle formed by the alternate long and short dash line FC with respect to the solid line FB. In this specification, this angle α is the inclination angle of the cord 44.

  In the front tire 6, the absolute value of the inclination angle α of the cord 44 is preferably 30 ° or more and 60 ° or less. By setting the absolute value of the inclination angle α to 30 ° or more, excessive rigidity due to the reinforcing layer 20 is suppressed. The front tire 6 is excellent in ride comfort. From this viewpoint, the absolute value of the inclination angle α is more preferably 40 ° or more. By setting the inclination angle α to 60 ° or less, the reinforcing layer 20 can effectively contribute to the rigidity feeling during braking. Since the front tire 6 is excellent in rigidity at the time of braking, the braking stability of the two-wheeled vehicle 4 can be improved. From this viewpoint, the absolute value of the inclination angle α is more preferably 50 ° or less.

  In the front tire 6, the density of the cord 44 is preferably 25 ends / 5 cm or more and 60 ends / 5 cm or less. By setting this density to 25 ends / 5 cm or more, the reinforcing layer 20 can improve the rigidity of the front tire 6. In this respect, the density is more preferably 30 ends / 5 cm or more. By setting the density to 60 ends / 5 cm or less, excessive rigidity due to the reinforcing layer 20 is suppressed. The front tire 6 is excellent in ride comfort. In this respect, the density is more preferably equal to or less than 55 ends / 5 cm. This density is obtained by measuring the number (ends) of the cords 44 existing per 5 cm width of the reinforcing layer 20 in a cross section perpendicular to the longitudinal direction of the cords 44. The density of the cords included in the reinforcing layer of the rear radial tire 8 described later is also measured in the same manner.

  In the front tire 6, the strength of the cord 44 is preferably 200N or more and 900N or less. According to the cord 44, breakage due to tension during braking is prevented. The net load applied to one cord 44 when the elongation percentage is 2% is expressed as the strength of the cord 44. This strength measurement is performed in accordance with the provisions of “JIS L 1017” under the condition that the temperature is 23 ° C. This strong unit is Newton (N). The strength of the cord included in the reinforcing layer of the rear radial tire 8 described later is also measured in the same manner.

  In FIG. 2, the double arrow line DF represents the length from the outer end 34 of the reinforcing layer 20 to the end 36 of the band 18. When the outer end 34 of the reinforcing layer 20 is radially outward from the end 36 of the band 18, the length DF is, in other words, the portion of the outer end 34 of the reinforcing layer 20 and the end 36 of the band 18. When the outer end 34 of the reinforcing layer 20 is radially inward of the end 36 of the band 18, in other words, the reinforcing layer 20 and the band 18 are overlapped with each other. The case where they are separated is indicated as negative.

  As described above, in the front tire 6, it is preferable that the outer end 34 of the reinforcing layer 20 and the end 36 of the band 18 are close to each other from the viewpoint of preventing formation of a portion having a specific rigidity. In this respect, the length DF is preferably −20 mm to 20 mm. From the viewpoint that the band 18 can effectively restrain the reinforcing layer 20, the length DF is more preferably 5 mm or more. From the viewpoint that excessive rigidity due to the overlapping portion of the reinforcing layer 20 and the band 18 is suppressed, the length DF is more preferably 15 mm or less.

  In the present invention, the size and angle of each member of the front radial tire 6 and the rear radial tire 8 to be described later are set so that the tires 6 and 8 are incorporated in the normal rim, It is measured in a state where the tires 6 and 8 are filled with air. At the time of measurement, no load is applied to the tires 6 and 8. In the present specification, the normal rim means a rim defined in a standard on which the tires 6 and 8 depend. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In this specification, the normal internal pressure means an internal pressure determined in the standard on which the tires 6 and 8 depend. “Maximum air pressure” in JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in TRA standard, and “INFLATION PRESSURE” in ETRTO standard are normal internal pressures.

  FIG. 5 is a cross-sectional view showing a part of the rear radial tire 8 constituting the tire pair 2 of FIG. In FIG. 5, the vertical direction is the radial direction, the horizontal direction is the axial direction, and the direction perpendicular to the paper surface is the circumferential direction. This circumferential direction is synonymous with the rotation direction. The rear radial tire 8 (hereinafter referred to as a rear tire) has a substantially bilaterally symmetric shape around a one-dot chain line CL in FIG. This alternate long and short dash line CL represents the equator plane of the rear tire 8. The rear tire 8 includes a tread 50, a sidewall 52, a bead 54, a carcass 56, a band 58, a reinforcing layer 60, an inner liner 62, and a chafer 64. The rear tire 8 is a tubeless type. The configuration of the rear tire 8 other than the reinforcing layer 60 is the same as that of the front tire 6 described above.

  Also in the rear tire 8, the reinforcing layer 60 is positioned on the inner side in the axial direction of the sidewall 52. The reinforcing layer 60 extends from the bead 54 along the carcass 56 outward in the radial direction. As shown in the figure, in the rear tire 8, an end 66 (hereinafter referred to as an outer end) located on the radially outer side of the reinforcing layer 60 is located in the vicinity of the end 68 of the band 58. More specifically, the outer end 66 is located radially outward from the end 68 of the band 58. In other words, the outer end 66 portion of the reinforcing layer 60 is covered with the end 68 portion of the band 58. Note that the outer end 66 may be located radially inward of the end 68 of the band 58.

  In the reinforcing layer 60, an end 70 (hereinafter referred to as an inner end) located on the radially inner side is located on a radially inner side with respect to an end 72 of the carcass ply 32. The inner end 70 is located in the vicinity of the core 74 of the bead 54. As shown in the drawing, the inner end 70 is located radially outward from the upper surface 76 of the core 74.

  The portion of the inner end 70 of the reinforcing layer 60 overlaps the bead 54 in the axial direction. More specifically, the inner end 70 portion overlaps the apex 78 of the bead 54 in the axial direction. As shown in the figure, the inner end 70 is sandwiched between the apex 78 and the carcass ply 80 on the axially outer side of the bead 54. In other words, the inner end 70 is laminated on the folded carcass ply 80a. The inner end 70 may be sandwiched between the apex 78 and the carcass ply 80b on the inner side in the axial direction of the bead 54.

  FIG. 6 is a schematic diagram showing the rear tire 8 of FIG. FIG. 7 is an enlarged plan view showing a part of FIG. FIG. 7 shows a portion of the inner end 70 of the reinforcing layer 60 of the rear tire 8. 6 and 7, an arrow line A represents the forward rotation direction of the rear tire 8. The vertical direction of the paper surface is the axial direction. An alternate long and short dash line RL represents the radial direction of the rear tire 8.

  In the rear tire 8, the reinforcing layer 60 includes a cord 82 and a topping rubber 84. The cord 82 is preferably an organic fiber cord made of nylon fiber, polyester fiber, rayon fiber, aramid fiber or polyethylene naphthalate fiber, or a steel cord whose material is steel. In the rear tire 8, an appropriate cord 82 is selected in consideration of its specifications and the like.

  As described above, in the rear tire 8, the reinforcing layer 60 extends along the carcass 56 outward from the bead 54 in the radial direction. Therefore, this cord 82 also extends along the carcass 56 from the bead 54 portion toward the outside in the radial direction. As illustrated, the cord 82 is inclined with respect to the radial direction. In the rear tire 8, the reinforcing layer 60 can effectively improve the rigidity of the side wall 52 portion. The rear tire 8 is excellent in maneuverability.

  In the rear tire 8, the cord 82 extends from the inner end 86 in an inclined direction opposite to the normal rotation direction. The inclination direction of the cord 82 is opposite to the inclination direction of the cord 44 included in the reinforcing layer 20 of the front tire 6 described above. The inclination direction of the cord 82 corresponds to the direction of stress applied to the rear tire 8 during acceleration. In particular, the reinforcing layer 60 can contribute to the rigidity of the rear tire 8 during acceleration. The rear tire 8 is excellent in rigidity. The rear tire 8 can improve the acceleration performance of the two-wheeled vehicle 4.

  In the rear tire 8, the reinforcing layer 60 is located in a portion from the vicinity of the end 68 of the band 58 to the vicinity of the core 74 of the bead 54. The reinforcing layer 60 does not hinder the riding comfort of the rear tire 8. The rear tire 8 is excellent in ride comfort.

  In FIG. 7, the alternate long and short dash line RC represents the center line of the cord 82. A solid line RB is a straight line that perpendicularly intersects the one-dot chain line RL at the inner end 86 of the cord 82. An angle β represents an angle formed by the alternate long and short dash line RC with respect to the solid line RB. In this specification, this angle β is the inclination angle of the cord 82. In the rear tire 8, the inclination direction of the cord 82 is opposite to the inclination direction of the cord 44 included in the reinforcing layer 20 of the front tire 6. Therefore, when the inclination angle α is expressed as a positive number, The angle β is represented by a negative number.

  In the rear tire 8, the absolute value of the inclination angle β of the cord 82 is preferably 30 ° or more and 60 ° or less. By setting the absolute value of the inclination angle β to 30 ° or more, excessive rigidity due to the reinforcing layer 60 is suppressed. The rear tire 8 is excellent in ride comfort. From this viewpoint, the absolute value of the inclination angle β is more preferably 40 ° or more. By setting the inclination angle β to 60 ° or less, the reinforcing layer 60 can effectively contribute to the feeling of rigidity during acceleration. Since the rear tire 8 is excellent in the feeling of rigidity during acceleration, the acceleration performance of the two-wheeled vehicle 4 can be improved. From this viewpoint, the absolute value of the inclination angle β is more preferably 50 ° or less.

  In the rear tire 8, the density of the cord 82 is preferably 25 ends / 5 cm or more and 60 ends / 5 cm or less. By setting this density to 25 ends / 5 cm or more, the reinforcing layer 60 can improve the rigidity of the rear tire 8. In this respect, the density is more preferably 30 ends / 5 cm or more. By setting the density to 60 ends / 5 cm or less, excessive rigidity due to the reinforcing layer 60 is suppressed. The rear tire 8 is excellent in ride comfort. In this respect, the density is more preferably equal to or less than 55 ends / 5 cm.

  In the rear tire 8, the strength of the cord 82 is preferably 200N or more and 900N or less. The cord 82 prevents breakage due to tension during braking.

  In FIG. 5, the double arrow line DR represents the length from the outer end 66 of the reinforcing layer 60 to the end 68 of the band 58. This length DR is determined when the outer end 66 of the reinforcing layer 60 is radially outward from the end 68 of the band 58, in other words, the portion of the outer end 66 of the reinforcing layer 60 and the end 68 of the band 58. When the outer end 66 of the reinforcing layer 60 is radially inward of the end 68 of the band 58, in other words, the reinforcing layer 60 and the band 58 are overlapped with each other. The case where they are separated is indicated as negative.

  In the rear tire 8 as well, the outer end 66 of the reinforcing layer 60 and the end 68 of the band 58 are close to each other from the viewpoint of preventing formation of a portion having a specific rigidity, as in the case of the front tire 6 described above. Is preferred. In this respect, the length DF is preferably −20 mm to 20 mm. From the viewpoint that the band 58 can effectively restrain the reinforcing layer 60, the length DF is more preferably 5 mm or more. From the viewpoint that excessive rigidity due to the overlapping portion of the reinforcing layer 60 and the band 58 is suppressed, the length DF is more preferably 15 mm or less.

  As described above, the tire pair 2 includes the front tire 6 and the rear tire 8, and each of the front tire 6 and the rear tire 8 is excellent in ride comfort. The front tire 6 and the rear tire 8 can effectively contribute to the riding comfort of the tire pair 2. In other words, the tire pair 2 is excellent in ride comfort.

  As described above, the front tire 6 is excellent in rigidity during braking, and the rear tire 8 is excellent in rigidity during acceleration. Each of the front tire 6 and the rear tire 8 can effectively contribute to the rigidity feeling of the tire pair 2. In other words, the tire pair 2 is excellent in rigidity. The tire pair 2 can effectively improve the braking stability and acceleration performance of the two-wheeled vehicle 4. Since the tire pair 2 is excellent in rigidity and ride comfort, the tire pair 2 can contribute to the improvement of the running performance of the two-wheeled vehicle 4.

  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.

[Example 1]
A tire pair comprising a front tire having the structure shown in FIG. 2 and having the specifications shown in Table 1 below, and a rear tire having the structure shown in FIG. 5 and having the specifications shown in Table 1 below. Got.

  The carcass ply cord constituting the carcass of the front tire is made of rayon fiber. The absolute value of the angle formed by this cord with respect to the equator plane is 90 °. The fineness of this cord is 940 dtex / 2. The band has a jointless structure. The cord included in this band is a steel cord. The configuration of the steel cord is “3 × 3 / 0.19”. The absolute value of the angle formed by the steel cord with respect to the equator plane is substantially zero. The cords included in the reinforcing layer extend inclining in the forward rotation direction from the inner end toward the radially outer side. The inclination angle α of this cord is 45 ° (degree). The density of this cord is 35 ends / 5 cm. The fineness of this cord is 1670 dtex / 2. This cord is made of an aramid fiber. The strength of this code is 500N. The outer end portion of the reinforcing layer and the end portion of the band overlap each other. The length DF from this outer end to this end is 15 mm. The size of the front tire is “120 / 70ZR17”.

  The carcass ply cord constituting the carcass of the rear tire is made of rayon fiber. The absolute value of the angle formed by this cord with respect to the equator plane is 90 °. The fineness of this cord is 940 dtex / 2. The band has a jointless structure. The cord included in this band is a steel cord. The configuration of the steel cord is “3 × 3 / 0.19”. The absolute value of the angle formed by the steel cord with respect to the equator plane is substantially zero. The cord included in the reinforcing layer extends from the inner end thereof to the outer side in the radial direction so as to be inclined in the direction opposite to the normal rotation direction. The inclination angle β of this cord is −45 ° (degree). The density of this cord is 35 ends / 5 cm. The fineness of this cord is 1670 dtex / 2. This cord is made of an aramid fiber. The strength of this code is 500N. The outer end portion of the reinforcing layer and the end portion of the band overlap each other. The length RF from this outer end to this end is 15 mm. The tire size of this rear tire is “190 / 55ZR17”.

[Examples 2 to 5]
A tire pair was obtained in the same manner as in Example 1 except that the cord inclination angle α and the cord inclination angle β were as shown in Table 1 below.

[Comparative Example 1]
A tire pair was obtained in the same manner as in Example 1 except that the rear tire was not provided with a reinforcing layer.

[Comparative Example 2]
A tire pair was obtained in the same manner as in Example 1 except that the reinforcing layer was not provided on the front tire.

[Comparative Example 3]
A tire pair was obtained in the same manner as in Example 1 except that the cord included in the reinforcing layer of the rear tire extended from the inner end of the cord in a forward rotation direction radially outward.

[Comparative Example 4]
The cord included in the reinforcing layer of the front tire extends in the same manner as in Example 1 except that the cord extends from the inner end thereof toward the radially outer side in a direction opposite to the normal rotation direction. Obtained.

[Comparative Example 5]
The cord included in the reinforcing layer of the front tire extends from the inner end of the cord toward the outside in the radial direction in a direction opposite to the normal rotation direction, and the cord included in the reinforcing layer of the rear tire has a radius from the inner end. A tire pair was obtained in the same manner as in Example 1 except that it extended in an inclined direction toward the outside in the forward direction.

[Reference Example 1]
Reference Example 1 is a conventional tire pair that is commercially available. The carcass included in each of the front tire and the rear tire is composed of two carcass plies. The absolute value of the angle formed by the cords included in each of these carcass plies with respect to the equator plane is 72 °. In Reference Example 1, the reinforcing layer is not provided.

[Running test]
The front tire was assembled in a rim of “MT3.50 × 17”, and this front tire was filled with air so that the internal pressure was 250 kPa. The rear tire was assembled in a rim of “MT6.00 × 17”, and this rear tire was filled with air so that the internal pressure was 290 kPa. This tire pair was mounted on a commercially available motorcycle (4 cycles) having a displacement of 750 cc. This motorcycle was run on a circuit course where the road surface was asphalt, and sensory evaluation on ride comfort and rigidity by the rider was performed. The results are shown as index values in Tables 1 and 2 below. The larger this value, the better.

  As shown in Tables 1 and 2, the tire pairs of the examples are excellent in ride comfort and rigidity. From this evaluation result, the superiority of the present invention is clear.

  The tire pair according to the present invention can be applied to various two-wheeled vehicles.

FIG. 1 is a perspective view showing a two-wheeled vehicle equipped with a tire pair according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a part of a front radial tire constituting the tire pair of FIG. FIG. 3 is a schematic view showing the front tire of FIG. FIG. 4 is an enlarged plan view showing a part of FIG. FIG. 5 is a cross-sectional view showing a part of a rear radial tire constituting the tire pair of FIG. FIG. 6 is a schematic view showing the rear tire of FIG. FIG. 7 is an enlarged plan view showing a part of FIG.

Explanation of symbols

2 ... Tire pair 4 ... Two-wheeled vehicle 6 ... Radial tire for front 8 ... Radial tire for rear 10, 50 ... Tread 12, 52 ... Side wall 14, 54 ... Bead 16, 56 ... Carcass 18, 58 ... Band 20, 60 ... Reinforcement layer 22, 62 ... Inner liner 24, 64 ... Chafer 26 ... Tread surface 28, 74 ... Core 30, 78 ... Apex 32, 32a, 80, 80a ... Carcass ply 44, 82 ... Cord 46, 84 ... Topping rubber 48, 86 ... Inner end

Claims (5)

(1) a tread whose outer surface forms a tread surface, a pair of sidewalls each extending substantially inward in the radial direction from an end of the tread, and a pair of beads positioned substantially inward in the radial direction from the sidewalls; A carcass spanned between the beads on both sides and having a radial structure, and a pair of reinforcing layers positioned on the inner side in the axial direction of the sidewalls,
This reinforcing layer has a cord,
This cord extends from the inner end of the cord in a forward rotation direction radially outward ,
The absolute value of the inclination angle of the cord, the tread forming a 30 ° or 60 ° der Ru front radial tire for as well as the following (2) an external surface to the tread surface, each with almost inward in the radial direction from an end of the tread A pair of extending sidewalls, a pair of beads positioned radially inward of the sidewalls , a carcass having a radial structure spanned between the beads on both sides, and positioned on the axially inner side of the sidewalls And a pair of reinforcing layers
This reinforcing layer has a cord,
The cord extends from the inner end thereof to the outer side in the radial direction inclining in the direction opposite to the normal rotation direction ,
The absolute value of the inclination angle of the cord, motorcycle tire pairs for automobile consisting of a radial tire for a rear Ru der 30 ° to 60 °. In the front radial tire, the cord is an organic fiber cord or a steel cord made of nylon fiber, polyester fiber, rayon fiber, aramid fiber or polyethylene naphthalate fiber,
The tire pair according to claim 1, wherein, in the rear radial tire, the cord is an organic fiber cord or a steel cord made of nylon fiber, polyester fiber, rayon fiber, aramid fiber, or polyethylene naphthalate fiber. The front radial tire further includes a band located radially inward of the tread,
The length from the outer end of the reinforcing layer to the end of the band is 20 mm or less,
The inner end portion of the reinforcing layer overlaps with the bead in the axial direction,
The radial tire for the rear further includes a band located radially inward of the tread,
The length from the outer end of the reinforcing layer to the end of the band is 20 mm or less,
The tire pair according to claim 1 or 2 , wherein an inner end portion of the reinforcing layer overlaps the bead in the axial direction. In the front radial tire, the cord has a density of 25 ends / 5 cm or more and 60 ends / 5 cm or less,
The tire pair according to any one of claims 1 to 3 , wherein in the rear radial tire, the cord has a density of 25 ends / 5 cm or more and 60 ends / 5 cm or less. In the front radial tire, the strength of the cord is 200N or more and 900N or less,
The tire pair according to any one of claims 1 to 4 , wherein in the rear radial tire, the strength of the cord is 200N or more and 900N or less.

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