JP2006298082A - Pneumatic tire for two-wheeler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively improve steering stability in turning traveling. <P>SOLUTION: A pair of belt reinforcing layers 34, 35 overlapped to each other on both end parts in the cross direction of inclined belts 27, 28 positioned at tread both end parts 13a, b is provided on the inside in the radial direction of a belt layer 25 and reinforcing cords 36, 37 inclined at an inclination angle B of more than 30 degrees against a tire equator S are buried in these belt reinforcing layers 34, 35, and consequently, in-plane shearing rigidity on the tread both end parts 13a, b is improved higher by the reinforcing cords 36, 37 in the belt reinforcing layers 34, 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a pneumatic tire for a motorcycle in which a tread portion is provided with at least one spiral belt.

    In general, in a pneumatic tire for a motorcycle, since the motorcycle body is almost upright with respect to the road surface when traveling straight, the center portion of the tread of the tire is mainly contacted with the road surface. Since it inclines with respect to the road surface, the tread end part mainly contacts the road surface. As a result, the grip for the circumferential direction input (acceleration / deceleration) during straight traveling is provided at the center of the tread of the pneumatic tire for a motorcycle, while the grip for the width direction (lateral direction) input during turning is provided at both ends of the tread. Is required.

Conventionally, as a pneumatic tire for two-wheeled vehicles in which such two grips are compatible to some extent, for example, a tire described in Patent Document 1 below has been proposed.
JP 2004-67058 A

  This includes a single layer spiral belt formed by winding a strip in which one or a plurality of reinforcing cords are embedded in a covering rubber around the tire equator S in a spiral shape around the tread portion, A belt composed of at least two layers of inclined belts, which are arranged so as to overlap with the spiral belt and in which a plurality of reinforcing cords inclined in the opposite direction with an inclination angle of 20 to 80 degrees with respect to the tire equator S are embedded. It has a layer.

  And this thing suppresses the tread part diameter growth due to the centrifugal force during high-speed running due to the high hoop effect of the spiral belt, thereby strongly suppressing the change in the ground contact shape, and thereby maneuvering during straight running While improving stability, the two-layer inclined belt, whose in-plane shear rigidity is higher than that of the spiral belt, suppresses deformation in the width direction of the tread during turning, thereby improving steering stability during turning. Yes.

    However, in such a conventional pneumatic tire for a motorcycle, there is a problem that the steering stability at the time of turning is not sufficient as compared with the steering stability at the time of straight running. In order to solve such a problem, for example, it is conceivable to increase the belt rigidity of the inclined belt by increasing the number of reinforcement cords driven in the inclined belt, and to increase the in-plane shear rigidity of both ends of the tread. Then, the out-of-plane bending rigidity at the center of the tread becomes excessive, and the steering stability during straight traveling is lowered, so that it cannot be adopted. Such a problem similarly occurs when at least one cross belt having a crossing angle of the reinforcing cord with respect to the tire equator of 90 degrees is used instead of the inclined belt.

    An object of the present invention is to provide a pneumatic tire for a motorcycle that can effectively improve steering stability during turning.

    Such an object is firstly constituted by winding a strip in which one or a plurality of reinforcing cords are embedded in a covering rubber around the tire equator S in a spiral shape around the tread portion. 1 layer of spiral belt and at least 2 layers of inclined belt which are arranged so as to overlap with the spiral belt and have a plurality of reinforcing cords embedded in the reverse direction at an inclination angle of less than 90 degrees with respect to the tire equator S In the pneumatic tire having a belt layer composed of the belt layer, the belt layer is overlapped with both ends in the width direction of the inclined belt located at both ends of the tread on the inner side in the radial direction of the belt layer, and 30 degrees or more with respect to the tire equator S inside. By providing at least one pair of belt reinforcing layers in which a large number of reinforcing cords inclined at an inclination angle are embedded, it can be achieved,

  Secondly, at least one layer of spiral belt formed by winding a strip in which one or a plurality of reinforcing cords are embedded in covering rubber around the tire equator S in a spiral shape around the tread portion; In a pneumatic tire having a belt layer which is arranged to overlap the spiral belt and which is composed of at least one cross belt in which a plurality of reinforcing cords are embedded at 90 degrees with respect to the tire equator S. A plurality of reinforcing cords are embedded in the belt layer on the inner side in the radial direction and overlapped at both ends in the width direction of the cross belt located at both ends of the tread, and are inclined at an inclination angle of 30 degrees or more with respect to the tire equator S. This can be achieved by providing at least one pair of belt reinforcement layers.

    According to the present invention, at least one pair of belt reinforcing layers that overlap each other in the widthwise ends of the inclined belt or the cross belt located at both ends of the tread on the radially inner side of the belt layer are provided, and the tire equator is provided in these belt reinforcing layers. Since the reinforcing cords inclined at an inclination angle of 30 degrees or more with respect to S are embedded, the in-plane shear rigidity at both ends of the tread is increased by the reinforcing cords in the belt reinforcing layer. The directional deformation is strongly suppressed, and the grip for the width direction (lateral direction) input is increased, and the steering stability during turning is improved. As a result, a pneumatic tire for a motorcycle having a good balance of steering stability during straight traveling and turning traveling can be easily obtained.

  Here, when the reinforcing cord in the belt reinforcing layer is inclined at an inclination angle of 30 degrees or more with respect to the tire equator S, the in-plane shear rigidity at both ends of the tread increases, but the inclination angle is according to claim 3. Thus, when the angle is 30 degrees or more and less than 60 degrees, the reinforcing cord itself resists lateral force. On the other hand, as described in claim 4, when the angle is 60 degrees or more and 90 degrees or less Since the reinforcing cords in the belt reinforcing layer connect the reinforcing cords in the spiral belt and integrate the reinforcing cords in the spiral belt against deformation due to lateral force, the in-plane shear rigidity is increased.

Moreover, if comprised as described in Claim 5, the belt rigidity of belt reinforcement layer itself will become high, and the in-plane shear rigidity in a tread both ends can be improved strongly.
Further, when turning with a two-wheeled vehicle, the vehicle body is gradually inclined and then gradually returned to the original upright state. Since the grip for the direction (lateral direction) input gradually changes (increases in the former and decreases in the latter), smooth maneuvering is possible.

Moreover, if comprised as described in Claim 7, the situation where the bending rigidity of a belt reinforcement layer becomes excessive can be prevented.
Furthermore, if comprised as described in Claim 8, the steering stability at the time of turning can fully be improved, maintaining the out-of-plane bending rigidity of a tread center part to a low value.

Embodiment 1 of the present invention will be described below with reference to the drawings.
1 and 2, 11 is a pneumatic radial tire for two-wheeled vehicles suitable for high-speed or ultra-high-speed driving. The tire 11 includes a tread portion 13 in which a tread surface 12 is smoothly curved in an arc shape, and a width direction of the tread portion 13. A tread end 17 includes a pair of sidewall portions 14 extending substantially radially inward from both ends, and a pair of bead portions 15 each having a bead core 16 embedded in the radially inner ends of the sidewall portions 14. The width between them is formed to be the maximum tire width.

  Further, the tire 11 has a carcass layer 20 that extends between the bead cores 16 in a toroidal shape and reinforces the sidewall portions 14 and the tread portions 13, and both end portions of the carcass layer 20 are axially inward around the bead cores 16. It is folded back toward the outside in the axial direction. The carcass layer 20 is composed of at least one carcass ply 21 here, and the inside of these carcass plies 21 intersects the tire equator S at a cord angle of 80 to 90 degrees, that is, substantially A large number of reinforcing cords 22 extending in the upper radial direction (the meridian direction) are embedded.

  As the reinforcing cord 22, an organic fiber cord such as nylon, rayon, or polyester is used. When the reinforcing cords 22 are inclined at an angle of less than 90 degrees with respect to the tire equator S, the reinforcing cords 22 are inclined in the opposite direction to the meridian direction in the two carcass plies 21. As a result, the reinforcing cords 22 cross each other in the two carcass plies 21. The tire 11 may be a bias tire in which the reinforcing cord 22 is inclined in the opposite direction at a cord angle of less than 80 degrees with respect to the tire equator S.

  Reference numeral 24 denotes a tread arranged on the outer side in the radial direction of the carcass layer 20. A belt layer 25 having a width substantially equal to the tread width is arranged in the tread portion 13 between the tread 24 and the carcass layer 20. The belt layer 25 is composed of at least one layer, here, one layer of spiral belt 26 and at least two layers, here, two layers of inclined belts 27, 28. In this embodiment, the radial direction of the spiral belt 26 Inclined belts 27 and 28 are arranged on the outer side so as to overlap the spiral belt 26.

  Note that the spiral belt 26 and the inclined belts 27 and 28 are arranged in an opposite relationship to that described above, and the inclined belt may be arranged inside the spiral belt in the radial direction. Here, the width of the inclined belts 27 and 28 is preferably set to be equal to or less than the tread width in order to prevent the occurrence of cracks at the belt ends of the inclined belts 27 and 28.

  The spiral belt 26 is formed by winding a strip in which one or a plurality of reinforcing cords 31 are embedded in a covering rubber in a spiral shape substantially along the tire equator S. As a result, the spiral belt 26 The reinforcing cord 31 embedded therein extends substantially in parallel to the tire equator S, and a strong arm is effective. Here, as the above-mentioned reinforcing cord 31, organic fiber such as nylon, rayon, polyester, aromatic polyamide or steel is used, but aromatic polyamide and steel that are lightweight but hardly stretch even at high temperatures. Is preferred.

  On the other hand, in the inclined belts 27 and 28, a plurality of reinforcing cords 29 and 30 extending in parallel with each other and inclined at an inclination angle A of less than 90 degrees with respect to the tire equator S are embedded, respectively. , 30 extend from one end in the width direction of the inclined belts 27, 28 to the other end in the width direction, and the cut ends are exposed at both ends in the width direction. The reinforcing cords 29 and 30 are inclined in the opposite direction to the tire equator S in the two-layer inclined belts 27 and 28. As a result, the reinforcing cords 29 and 30 intersect each other. Here, as the reinforcing cords 29 and 30, organic fibers such as nylon, rayon, polyester, aromatic polyamide, or steel are used.

  Here, the inclination angle A of the reinforcing cords 29 and 30 with respect to the tire equator S is 60 degrees or more in order to reduce the out-of-plane bending rigidity in the tread central portion 13c and improve the steering stability during straight traveling. However, in this case, the in-plane shear rigidity of the tread portion 13, particularly the tread end portions 13 a and b, is reduced, and the steering stability during turning traveling described in the above-described problem is further remarkable. It becomes.

  At least one pair, in this case, a pair of belt reinforcing layers 34, 35 are provided on the radially inner side of the belt layer 25, specifically, between the carcass layer 20 and the spiral belt 26, and these belt reinforcing layers 34 are provided. , 35 overlap with both ends in the width direction of the inclined belts 27, 28 located at both ends 13a, b of the tread. Further, a plurality of reinforcing cords 36 and 37 that are inclined at an inclination angle B of 30 degrees or more with respect to the tire equator S are embedded in the belt reinforcing layers 34 and 35, respectively.

  In this manner, a pair of belt reinforcing layers 34 and 35 are provided on the inner side in the radial direction of the belt layer 25 and overlap each other at both ends in the width direction of the inclined belts 27 and 28 located at the tread both ends 13a and b, Since the reinforcement cords 36 and 37 inclined at an inclination angle B of 30 degrees or more with respect to the tire equator S are embedded in the belt reinforcement layers 34 and 35, the in-plane shear rigidity at the tread end portions 13a and 13b is the belt reinforcement layer. The height is increased by the reinforcing cords 36 and 37 in the 34 and 35, and thereby, the deformation in the width direction of the tread portion 15 during turning is strongly suppressed, and the grip with respect to the input in the width direction (lateral direction) is increased to turn. This improves the handling stability during driving.

  As a result, the pneumatic tire 11 for a two-wheeled vehicle having a good balance of steering stability during straight traveling and turning traveling can be easily obtained. Here, if the belt reinforcing layers 34 and 35 are disposed radially inside the belt layer 25 as described above, the tread 24 and the spiral belt made of rubber are provided between the belt reinforcing layers 34 and 35 and the road surface. 26, the belt layer 25 having a high rigidity composed of the inclined belts 27 and 28 is interposed, and therefore, a rigid step generated at the inner ends in the width direction of the belt reinforcing layers 34 and 35 hardly appears on the tread surface 12 of the tread portion 13. As a result, smooth maneuvering is possible during turning.

  When the inclination angle B of the reinforcing cords 36 and 37 with respect to the tire equator S is less than 30 degrees, the in-plane shear rigidity at the tread end portions 13a and 13b is almost improved as in the reinforcing cord 31 in the spiral belt 26. In addition, since the out-of-plane bending rigidity at the tread end portions 13a and 13b is increased and the vibration riding comfort and the steering stability during turning are lowered, it cannot be used.

  On the other hand, when the reinforcing cords 36 and 37 in the belt reinforcing layers 34 and 35 are inclined at an inclination angle B of 30 degrees or more with respect to the tire equator S, the in-plane shear rigidity at the tread ends 13a and 13b is high as described above. However, the mechanism is different between the case where the inclination angle B is 30 degrees or more and less than 60 degrees and the case where the inclination angle B is 60 degrees or more and 90 degrees or less.

  That is, when the inclination angle B is 30 degrees or more and less than 60 degrees, the reinforcing cords 36 and 37 themselves resist the lateral force, so that the in-plane shear rigidity at the tread ends 13a and b increases. On the other hand, in the case of 60 degrees or more and 90 degrees or less, the reinforcing cords 36 and 37 in the belt reinforcing layers 34 and 35 connect the reinforcing cords 31 in the spiral belt 26 to each other and spiral against deformation due to lateral force. By integrating the reinforcing cord 31 in the belt 26, the in-plane shear rigidity at the tread end portions 13a and 13b is increased.

  When the inclination angle B is not less than 60 degrees and not more than 90 degrees as described above, it is preferable to use steel as the reinforcing cords 36 and 37. The reason is that steel has a strong resistance against both compressive force and tensile force, so that it can be strongly connected regardless of the force acting on the reinforcing cord 31 in the spiral belt 26. Because you can.

  Here, the width L of the belt reinforcing layers 34 and 35 is preferably in the range of 10 to 100 mm. The reason is that if the width L is less than 10 mm, the range of the region where the in-plane shear rigidity is high becomes narrow and the steering stability at the time of turning cannot be sufficiently improved, while if it exceeds 100 mm, In a general motorcycle tire, the inner ends in the width direction of the belt reinforcing layers 34 and 35 extend to the tread central portion 13c, and the out-of-plane bending rigidity at the tread central portion 13c becomes high. This is because the steering stability during turning can be sufficiently improved while maintaining the out-of-plane bending rigidity of the tread central portion 13c at a low value.

  Further, as the reinforcing cords 36 and 37 in the belt reinforcing layers 34 and 35, organic fibers such as nylon, rayon, polyester, and aromatic polyamide, or steel are used, but they are almost lightweight and stretch even at high temperatures. Aromatic polyamide and steel are preferred.

    3 and 4 are views showing Embodiment 2 of the present invention. In this embodiment, the belt layer 40 includes at least one layer similar to the spiral belt 26, in this case, one layer of the spiral belt 41 and a plurality of reinforcing cords 42 intersecting the tire equator S at 90 degrees. The cross belt 43 is composed of at least one buried layer, in this embodiment, one cross belt 43, and the cross belt 43 is arranged on the inner side in the radial direction of the spiral belt 41 so as to overlap the spiral belt 41.

  The arrangement relationship of the spiral belt 41 and the cross belt 43 is opposite to the above, and a cross belt may be arranged on the outer side in the radial direction of the spiral belt, and the width of the cross belt 43 is determined by the cross belt. In order to prevent the occurrence of cracks at the belt end of 43, the width is preferably equal to or less than the tread width. Further, as the reinforcing cord 42, an organic fiber such as nylon, rayon, polyester, aromatic polyamide or steel is used.

  Further, in this embodiment, at least one pair, in this case, two pairs of belt reinforcing layers 46, 47, 48, 49, radially inward of the belt layer 40, specifically, between the carcass layer 20 and the cross belt 43. These belt reinforcing layers 46, 47, 48, and 49 are overlapped with both ends in the width direction of the cross belt 43 positioned at the tread ends 13a and b, respectively. At this time, it is preferable that the width direction outer ends of the belt reinforcing layers overlapping each other, that is, the belt reinforcing layers 46, 48 and 47, 49 are slightly shifted in the width direction in order to suppress the occurrence of cracks and the like.

  In addition, a plurality of reinforcing cords 50, 51, 52, 53 inclined at an inclination angle B of 30 degrees or more with respect to the tire equator S are respectively provided in the belt reinforcing layers 46, 47, 48, 49 as described above. Buried. Even in this configuration, as described above, deformation in the width direction of the tread portion 15 at the time of turning travel is strongly suppressed, and the grip for the input in the width direction (lateral direction) is increased, and at the time of turning travel. Steering stability is improved.

  When two or more pairs of belt reinforcing layers 46, 47, 48, 49 are provided as described above, the reinforcing cords 50 in the belt reinforcing layers overlapping each other, that is, in the belt reinforcing layers 46, 48 and 47, 49, It is preferable that the inclination directions of 52, 51 and 53 intersect with the tire equator S in the opposite direction. This is because the belt rigidity of the overlapping belt reinforcing layers 46, 48 and 47, 49 itself is increased in this way, and the in-plane shear rigidity at the tread ends 13a, b can be strongly improved. is there.

  Further, as described above, when two or more pairs of belt reinforcing layers 46, 47, 48, 49 are provided, a pair of belt reinforcing layers, that is, between the pair of belt reinforcing layers 46, 47 and 48, 49 are provided. In this embodiment, the former is wide, the latter is narrow, and the belt reinforcement layers 48 and 49 that are narrow are overlapped on the outer sides in the width direction of the belt reinforcement layers 46 and 47 that are wide. It is preferable to gradually improve the in-plane shear rigidity toward the outside in the width direction.

  The reason for this is that when turning with a two-wheeled vehicle, the vehicle body is gradually tilted and then gradually returned to the original upright state. This is because a smooth maneuvering is possible because the grip for the (direction) input gradually changes (increases in the former and decreases in the latter).

  Further, as the above-described reinforcing cords 50, 51, 52, 53, organic fibers such as nylon, rayon, polyester, aromatic polyamide, or steel can be used. As described above, the belt reinforcing layers 46, 47, 48 are used. , 49 when two or more pairs are provided, if the reinforcing cords 50, 51, 52, 53 in all the belt reinforcing layers 46, 47, 48, 49 are made of steel, the belt reinforcing layers 46, 47, 48 Because the bending rigidity of 49 is excessive, the reinforcement cord embedded in at least one pair of belt reinforcement layers is made of organic fibers to prevent the bending rigidity of the entire belt reinforcement layer from becoming excessive. It is preferable to do.

  For example, the reinforcement cords 50, 51, 52, 53 in the two pairs of belt reinforcement layers 46, 47, 48, 49 are all made of aromatic polyamide, or the reinforcement cords in the wide belt reinforcement layers 46, 47 50 and 51 can be made of aromatic polyamide, and the reinforcing cords 52 and 53 in the narrow belt reinforcing layers 48 and 49 can be made of steel. Other configurations and operations are the same as those of the first embodiment.

    Next, Test Example 1 will be described. In this test, the tires 1 and 2 as shown in FIGS. 1 and 2 in which a pair of belt reinforcing layers are disposed between the carcass layer and the spiral belt at both ends of the tread, and the carcass layer and the cross belt at both ends of the tread. 3 and 4 in which two pairs of belt reinforcing layers having different widths are arranged, and an actual tire 4 that is the same as the working tire 3 except that the pair of belt reinforcing layers is a pair. The comparison tire 1 is the same as the implementation tire 1 except that the belt reinforcement layer is excluded from the implementation tire 1, and the comparison tire 2 is the same as the implementation tire 3 except that the belt reinforcement layer is excluded from the implementation tire 3. And prepared.

  Here, the size of each tire is 190 / 50ZR17, and the carcass layer of each tire is composed of two carcass plies embedded with reinforcing cords that intersect the tire equator S at 90 degrees, A reinforcing cord with a nylon filament diameter of 0.5 mm was used. In addition, a spiral belt of one layer is wound in a spiral shape along the tire equator S by strips of two reinforced cords with a diameter of 0.7 mm, twisted together of aromatic polyamide filaments, embedded in parallel in the covered rubber. It was composed by doing. Here, the spacing between the reinforcing cords in the spiral belt was 30/50 mm.

  Further, in each of the inclined belts in the tires 1 and 2 and the comparative tire 1, a reinforcing cord having a diameter of 0.7 mm twisted with an aromatic polyamide filament is driven into the inclined belt at a spacing of 30/50 mm, opposite to the tire equator S. It was buried while tilting in the direction at 70 degrees. Further, in the tire 1 described above, a reinforcing cord having a diameter of 0.7 mm obtained by twisting filaments of aromatic polyamide in a belt reinforcing layer having a width of 50 mm is driven into each of the tire equator S at an interval of 30/50 mm. On the other hand, in the implementation tire 2, 1 × 3 type reinforcement cords made by twisting steel filaments with a wire diameter of 0.21 mm in a belt reinforcement layer with a width of 50 mm are driven. The tires were buried at an interval of 20/50 mm and inclined at 60 degrees with respect to the tire equator S.

  On the other hand, in the crossed belts of the tires 3 and 4 and the comparative tire 2, a reinforcing cord having a diameter of 0.7 mm twisted with an aromatic polyamide filament is driven at an interval of 30/50 mm and 90 degrees with respect to the tire equator S. Buried while crossing. Further, in the implementation tire 3, a reinforcing cord having a diameter of 0.7 mm obtained by twisting filaments of aromatic polyamide in an outer wide belt reinforcing layer having a width of 60 mm is driven into the tire equator S at an interval of 30/50 mm. While embedding at an angle of 45 degrees, a reinforcing cord with a diameter of 0.7 mm made by twisting filaments of aromatic polyamide in the inner narrow belt reinforcement layer with a width of 35 mm is driven at 30/50 mm intervals. The tire equator S was buried while being inclined at 45 degrees in the direction opposite to the reinforcing cord in the wide belt reinforcing layer.

  Here, the narrow belt reinforcing layer is overlapped with the wide belt reinforcing layer while being protruded by 5 mm from the outer end of the wide belt reinforcing layer. As a result, the width of the portion where only the wide belt reinforcing layer is arranged is 30mm, the width of the part where the wide and narrow belt reinforcement layers overlap is 30mm, and the width of the part where only the narrow belt reinforcement layer is arranged is 5mm. Further, in the tire 4 described above, a reinforcing cord having a diameter of 0.7 mm obtained by twisting filaments of aromatic polyamide in a belt reinforcing layer having a width of 50 mm is driven into the tire equator S at an interval of 30/50 mm. It was buried while tilting at a degree.

Next, after filling each tire with an internal pressure of 220 kPa, it was mounted on a sports type motorcycle having a displacement of 1000 cm ³ (cc). Here, since each tire was a rear tire, Only the rear tire was replaced, and the same tire was used for the front tire. Next, run the test course with a motorcycle like this, drive straight running performance (traction performance) with a skilled test driver, steering stability when turning the car body (cornering performance), and tilting operation. Evaluation of ease was performed.

  As a result, when the perfect score is 10 points, the straight running performances of the tires 1 and 2 and the comparative tire 1 are 8 points, 8 points, and 8 points, respectively, and the steering stability during turning is 9 points, 9 points, and 6 points, respectively. The ease of the tilting operation was 8 points, 8 points, and 8 points, respectively. On the other hand, the straight running performances of the tires 3 and 4 and the comparative tire 2 are 9 points, 9 points, and 9 points, respectively, the steering stability during turning is 9 points, 8 points, and 5 points, respectively. They were 9 points, 8 points, and 8 points, respectively.

  From the driver, the implementation tire 1 has the same traction as the comparison tire 1 when going straight, and the lateral grip when the vehicle body is greatly inclined is very high. In addition to the same, there was a comment that the feeling is very close to the implementation tire 1. In addition, although the comparison tire 1 has good traction when going straight, it is slightly harder than the comparison tire 2, and it is a little firm at the corner, but there is a comment that the grip is still low .

  Further, the implementation tire 3 has good traction when compared with the comparative tire 2 when traveling straight, and the lateral grip when the vehicle body is greatly inclined is very high. Further, the lateral force gradually increases as the vehicle body is largely inclined. The tire 4 has good traction with the same degree of traction as the comparative tire 2 when going straight, and it feels good when cornering, especially when the car body is greatly inclined. There was a comment to grip when you did. Moreover, although the comparative tire 2 had softness and the traction performance was high when going straight ahead, there was a comment that there was a grip loss at the corner and a feeling of crumble at the corner.

  From these results, the structure of the present invention can greatly improve the lateral grip during turning without deteriorating the traction performance when going straight, and thus the balance of steering stability when going straight and turning. Can be understood to be good. In comparison with the implementation tire 1 and the implementation tire 4, in the implementation tire 1, the cord layer in which the reinforcement cords inclined at both ends of the tread are embedded is laminated in three layers including the belt reinforcement layer. It becomes higher than the implementation tire 4, and as a result, it is thought that the evaluation at the time of turning became high.

  The present invention can be applied to the industrial field of pneumatic tires for motorcycles.

1 is a meridian cross-sectional view of a tire showing Embodiment 1 of the present invention. FIG. It is a meridian sectional view of a tire showing a second embodiment of the present invention. FIG.

Explanation of symbols

11 ... Pneumatic tires for motorcycles 13 ... Tread
13a, b ... both ends of tread 25 ... belt layer
26 ... spiral belt 27, 28 ... inclined belt
29, 30 ... Reinforcement cord 31 ... Reinforcement cord
34, 35 ... Belt reinforcement layer 36, 37 ... Reinforcement cord
42 ... Reinforcement cord 43 ... Cross belt

Claims (8)

    At least one spiral belt formed by winding a strip in which one or a plurality of reinforcing cords are embedded in a covering rubber around the tire equator S in a spiral shape around the tread portion, and the spiral belt And an air having a belt layer composed of at least two inclined belts embedded with a plurality of reinforcing cords inclined in the opposite direction with an inclination angle of less than 90 degrees with respect to the tire equator S. A plurality of reinforcing cords that overlap with both ends in the width direction of the inclined belt located at both ends of the tread on the inner side in the radial direction of the belt layer and are inclined at an inclination angle of 30 degrees or more with respect to the tire equator S A pneumatic tire for a motorcycle, comprising at least one pair of belt reinforcing layers embedded with a belt.     At least one spiral belt formed by winding a strip in which one or a plurality of reinforcing cords are embedded in a covering rubber around the tire equator S in a spiral shape around the tread portion, and the spiral belt A pneumatic tire having a belt layer which is arranged to overlap with the tire equator S and has at least one cross belt in which a plurality of reinforcing cords crossing at 90 degrees with respect to the tire equator S are embedded. At least one reinforcing cord is embedded in each of the cross belts positioned at both ends of the tread in the radial direction of the tire and overlapped with each other in the width direction of the cross belt and inclined at an inclination angle of 30 degrees or more with respect to the tire equator S. A pneumatic tire for a motorcycle, comprising a pair of belt reinforcing layers.     The pneumatic tire for a motorcycle according to claim 1 or 2, wherein an inclination angle of the reinforcing cord embedded in the belt reinforcing layer with respect to the tire equator S is in a range of 30 degrees or more and less than 60 degrees.     The pneumatic tire for a motorcycle according to claim 1 or 2, wherein an inclination angle of the reinforcing cord embedded in the belt reinforcing layer with respect to the tire equator S is in a range of 60 degrees to 90 degrees.     3. The pneumatic tire for a motorcycle according to claim 1, wherein when two or more pairs of the belt reinforcing layers are arranged, the inclination directions of the reinforcing cords in the belt reinforcing layers that overlap each other intersect with the tire equator S in the opposite direction. .     When two or more pairs of the belt reinforcement layers are arranged, the widths of the belt reinforcement layers forming a pair are made different, and the narrow belt reinforcement layer is overlapped on the outer side in the width direction of the wide belt reinforcement layer. The pneumatic tire for a motorcycle according to claim 1 or 2.     The pneumatic tire for a motorcycle according to claim 1 or 2, wherein when two or more pairs of the belt reinforcing layers are arranged, the reinforcing cords embedded in at least one pair of belt reinforcing layers are made of organic fibers.     The pneumatic tire for a motorcycle according to claim 1 or 2, wherein a width of the belt reinforcing layer is in a range of 10 to 100 mm.

Images