JP2007083815A - Pneumatic tire for two-wheeler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire for a two-wheeler capable of maintaining riding comfort, and superior in steering stability performance during a turn when the body of the two-wheeler is widely inclined. <P>SOLUTION: The pneumatic tire 10 for the two-wheeler comprises a bead core 20, a bead part 18, a carcass 16, a spiral belt layer 22 arranged outside in the tire radial direction of the carcass, and a tread 28 arranged outside in the tire radial direction of the spiral belt layer 22. When it is defined that the tread consideration of the tread 28 between the tire equatorial plane CL (point C) and an end of the tread 28 (point A) is L, an inclined belt layer 24 with a plurality of cords inclined at the angle of 30-90° with respect to the tire circumferential direction being embedded in a cover rubber is arranged between a point P away from the point A to the point C by L/3 along the tread and a point Q away from the point C to the point A by L/6 along the tread. The riding comfort in the straight traveling mode can be maintained, and the steering stability in a turning mode when the body is widely inclined is good. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire for a motorcycle excellent in steering stability performance at high speed traveling, and more particularly, to a pneumatic tire for a motorcycle excellent in straight running stability performance and steering stability performance in deep cornering that greatly depresses the vehicle.

  In a pneumatic tire for a high-performance motorcycle, the rotational speed of the tire becomes high when traveling at a high speed, so that the influence of centrifugal force is large, and the tire tread portion expands outward, which may impair steering stability performance. For this reason, a tire structure in which a reinforcing member (spiral member) made of organic fiber or steel is wound around the tread so as to be substantially parallel to the tire equatorial plane is known. In this tire structure, nylon fiber, aromatic polyamide (Kevlar: trade name), steel, or the like is used as a reinforcing member wound spirally along the tire equatorial plane. Among them, aromatic polyamide and steel are attracting attention because they can suppress expansion of the tread portion without stretching even at high temperatures. When these members are wound around the crown of the tire, the so-called “tangle” effect (the tire is pressed by the centrifugal force even when the tire is pressed at a high speed by pressing the crown of the tire like a bathtub Many patents characterized in that the spiral member is arranged in the crown portion of the tire have been filed. (For example, Patent Documents 1, 2, 3, 4, 5)

  It is known that a tire around which these spiral members are wound is excellent in handling stability performance at high speed and has very high traction. However, as for the turning performance when the vehicle (motorcycle) is largely defeated, the speed is low, so the influence of centrifugal force is small, and just because the spiral member is wound, the advantage of the spiral member "Is not enjoyed, and steering stability performance is not improved dramatically. Consumers and riders who are racing may be asked to improve grip when a bike is knocked down. When turning a vehicle with a large tilt, a large lateral force is applied to the tire, and if the lateral rigidity of the tire is not firm, the tire will become deformed and lose its rigidity. I feel it is low.

  Similarly, even in a conventional pneumatic tire for a motorcycle having a crossing belt that does not use a spiral member, if the grip force at the time of turning can be increased, the steering stability performance of the tire can be improved. However, when the vehicle is turned down significantly, a large lateral force is applied to the tire, and if the lateral rigidity of the tire is not firm, the deformation of the tire will increase and the rigidity will be lost, and the rider will have a low grip I feel.

  As a countermeasure to this problem, in order to ensure the lateral rigidity of the pneumatic tire for a motorcycle, a hard rubber called a bead filler provided in the tire bead part is enlarged, or a plurality of inserts called inserts are provided on the side part of the tire. A technique for improving the lateral rigidity of the tire by restraining deformation of the side portion of the tire by adding an angled reinforcing member in which a cord of the book is embedded in the covering rubber is known.

  By the way, the pneumatic tire for a motorcycle has a major feature that the place where the tire tread portion is in contact with the ground is different between when traveling straight and when turning because the motorcycle turns while tilting the vehicle body. That is, there is a feature that the center portion of the tread portion (hereinafter referred to as the tread center) is used when going straight, and the end portion of the tread portion (hereinafter referred to as the tread shoulder) is used when turning. Therefore, the tread portion is provided wider than the tire side portion, and the influence of the rigidity of the tread portion, that is, the belt portion corresponding to the tread portion, is very large on the rigidity of the tire. Therefore, even if only the tire side portion is reinforced, it may not be sufficient for lateral deformation. In particular, with respect to turning performance when the vehicle body is largely tilted, the tread shoulder on one side of the tire is grounded to generate a grip force.

  At this time, the tread center is not grounded, and the tread center serves as a tire side portion. In other words, only the tread shoulder on one side of the tire is in contact with the road surface, and the force transmitted from the road surface integrates the side part on the grounded side with the tread shoulder and the side part on the non-grounded side. It is transmitted to the structure and the wheel is turned to the foil. Unlike pneumatic tires for passenger cars and trucks, the tread center of a non-contact part has a role as if it were a side part when turning, because of the characteristic of turning the tire when turning it (Fig. 5 (B)). reference).

  Considering these characteristics, the rigidity of the belt portion of the tire is also an important factor in improving the tire rigidity in the lateral direction. Regarding the rigidity of the belt part of the tire, the number of intersecting belt members is increased to 3 to increase the shear rigidity of the belt and the ring rigidity, and the steel cord and kevlar (aromatic) so as to be approximately parallel to the equator direction. Group ring) can be used to increase the ring rigidity by spirally winding the cord, but if the belt rigidity is increased as much as possible, the tire itself will become very hard and There is a problem that steering stability performance is impaired.

On the other hand, a low-rigidity tread that does not have a reinforcing belt when running straight by placing a reinforcing belt that has a tire tread shoulder and a plurality of cords inclined between the tread part and the carcass embedded in the coated rubber Because it receives a load from the road surface at the center, it is excellent in straight running stability, vibration absorption or shock absorption, and when turning, it receives a load in a highly rigid area where a reinforcing belt is placed, so grip power is high and turning control is stable A pneumatic tire for motorcycles that is excellent in performance is known. (For example, Patent Documents 6 and 7)
JP 2004-067059 A JP 2004-067058 A JP 2003-011614 A JP 2002-316512 A JP 09-226319 A JP 2001-206209 A JP 2002-316512 A

  As described above, in a pneumatic tire for a motorcycle, the location where the tire tread portion contacts the road surface differs between straight running and turning, and the tread portion may behave as a sidewall. In addition to increasing the rigidity of the part, increasing the rigidity of the tread part is also important for increasing the rigidity of the tire during turning.

  However, increasing the rigidity of the entire belt corresponding to the tread portion is not preferable because the ride comfort performance is extremely deteriorated, and like the pneumatic tires for motorcycles disclosed in Patent Documents 6 and 7. If the reinforcement belt is placed in the area corresponding to the tread shoulder to increase the rigidity of the tire, the steering stability performance during turning is excellent, but the out-of-plane rigidity of the belt increases and the belt becomes difficult to deform (the belt is on the road surface). There is a problem that the ground contact area is reduced and the gripping force is reduced.

  In general, with regard to the tilt at the time of turning of the motorcycle, it was found from the vehicle observation that the vehicle was tilted about 55 degrees at maximum with respect to the ground when violent maneuvering was performed during circuit driving. That is, the tire camber angle (CA) is used up to about 55 degrees. CA (camber angle, camber angle) is a very large angle such as 55 degrees when the turning radius is small at a low-speed corner. Further, it is known that the vehicle body falls about 45 degrees on a general road.

  Here, the inventor has devised to increase the rigidity only in the range immediately adjacent to the tread portion that is in contact with the road surface when the tire is turned with a large inclination. The aim is to reinforce only the most effective portion of the tire tread portion and keep the other portions soft, so that both the ride comfort performance and the steering stability performance when turning the vehicle body are greatly reduced.

  An object of the present invention is to provide a pneumatic tire for a two-wheeled vehicle that maintains riding comfort performance and is excellent in steering stability performance at the time of turning the vehicle body greatly down in consideration of the above facts.

  A pneumatic tire for a motorcycle according to claim 1 of the present invention includes a bead core embedded in a pair of left and right bead portions, a toroidal shape extending from one bead portion to the other bead portion, and an end portion wound around the bead core. And a belt-like rubber in which a carcass made of at least one carcass ply engaged with the bead core and one or a plurality of cords arranged in parallel in the tire radial direction of the carcass are embedded in the covering rubber. A pneumatic tire for a motorcycle including at least one spiral belt formed by winding a covering cord in a spiral shape, and a tread portion disposed on the outer side in the tire radial direction of the spiral belt, the tire width direction In the cross section, when the tread tread distance between the tire equatorial plane and the tread edge is L, the tread edge to the tire equatorial plane side Between the first position of L / 3 along the red tread and the second position of L / 6 along the tread tread from the tire equatorial plane to the tread end side, an angle with respect to the tire circumferential direction is 30 to 30 °. At least one angled reinforcing member in which a plurality of cords of 90 degrees are embedded in a covering rubber is arranged.

Next, the function and effect of the pneumatic tire for a motorcycle according to claim 1 will be described.
In the first aspect of the present invention, in the tire radial cross section, the tread tread surface distance between the intersection C between the tread tread and the tire equatorial plane, the point A as the tread edge, and the C point and A point is L (L = 0. 5TW), the first position that is L / 3 away from point A toward point C along the tread tread is defined as point P, and the point L from point C toward point A along the tread tread is defined as L The second position, which is a position / 6 away, is defined as the Q point, and it is clearly stated that the tread portion between the P point and the Q point increases the rigidity. The positional relationship between the point P and the point Q is as shown in FIG.

  In defining P point, the reason why L / 3 is used from the tread edge (A point) to the tire equator plane (C point) is that the road surface when the car body is greatly tilted and the camber angle exceeds 45 degrees This is because the tread portion that contacts R (two-dot chain line) is in the range of L / 3 from the tread end (point A) to the tire equatorial plane side, as shown in FIG. In an average pneumatic tire for a motorcycle, in cornering where the vehicle body is greatly tilted, only about one-sixth of the full width of the tread (tread tread surface distance) is in contact with the road surface R. That is, as in the present claim, when L is a half of the full width of the tread portion, the range of L / 3 is in contact with the road surface R. Increasing the belt rigidity in the tire contact area increases the out-of-plane rigidity of the belt and makes it difficult for the belt to deform (because the belt cannot be deformed following the road surface), reducing the contact area with the road surface R. End up.

  Here, at the time of turning with the vehicle body greatly tilted, that is, cornering that requires a large lateral force as in the present invention, in the region of L / 3 from the tread end (region between the points A and P). In addition, by increasing the rigidity of the immediately adjacent region (the region between the point P and the point Q), it is possible to increase the rigidity at the time of turning of the tire without reducing the contact area with the road surface R. As a result, the steering stability performance during turning is improved.

  Next, as the definition of the Q point, a value of L / 6 was used from the tire equatorial plane (C point) toward the tread end (A point) side. This is shown in FIG. 5 (A) when the vehicle is traveling straight, that is, when the vehicle is traveling at a camber angle of 0 degrees, the range in contact with the road surface R is an average motorcycle pneumatic tire. Thus, only about one sixth of the entire width of the tread portion is in contact with the road surface R. (When cornering and when traveling straight, the contact width with the road surface R is roughly the same. Both are about 1/6 of the total tread width). That is, when half of the full width of the tread portion is L as in the present claim, the contact portion with the road surface R is in a range of L / 6 on both sides of the tire equatorial plane (point C) of the tread portion. Become. Therefore, the Q point is such a definition.

  Here, the reason why the rigidity of the tire center portion is not increased is as follows. 1) When the rigidity of the tire center portion is high (when the belt rigidity in the tire center portion is very high), the ride comfort performance is impaired (especially in general In urban areas, most of them are upright, and increasing the belt rigidity of the tire center will significantly deteriorate the vibration absorption performance). 2) Maintaining traction performance and braking performance by keeping the tread center belt firm and not reducing the ground contact area during straight travel. 3) Since the belt rigidity is high at both sides of the tire equatorial plane of the tread portion, there is a firm feeling of the tire even when going straight ahead.

  By only increasing the rigidity between point P and point Q, vibration ride comfort performance during straight travel is maintained, and tire rigidity (lateral rigidity) during turning is enhanced, so steering stability during turning is stable. Excellent performance. Therefore, the riding comfort performance is maintained and the steering stability performance at the time of turning with the vehicle body greatly lowered is excellent.

  It should be noted that the traveling state where the region between the point P and the point Q is in contact with the ground is a turn when the vehicle body is not largely tilted, and a large lateral force is not required, so even if the belt rigidity is high. It won't be a big problem. Also, in motorcycle racing, the vehicle body is often largely defeated during turning, and the region between points P and Q is in the moment of defeating the vehicle body, and the frequency of use is low. Very low. Therefore, in the turning state when the vehicle body is largely collapsed, it is important to improve the steering stability performance in the race driving because it tends to shorten the time.

  Further, it is not necessary to arrange the angled reinforcing member for the entire range between the point P and the point Q to increase the rigidity of the belt, and a sufficient effect can be obtained if the rigidity is increased for a part of the range. Of course, it does not matter if the rigidity is increased for everything in between.

  Further, since the cord of the spiral belt has an angle with respect to the tire circumferential direction of approximately 0 degrees (about 0 to 3 degrees), in order to increase the belt rigidity, the angle of the cord with respect to the tire circumferential direction is 0 degree. Compared with the addition of the angled reinforcement member, the angled reinforcement member having an angle intersecting with the cord of the spiral belt such as an angle of the cord of 30 to 90 degrees can achieve a higher effect. Here, the angle of the cord with respect to the circumferential direction of the tire is set to 30 degrees or more when considering the crossing with the cord of the spiral belt of approximately 0 degrees, if there is no angle difference of 30 degrees or more, the angled reinforcing member This is because does not function as a crossing layer. The upper limit is 90 degrees, and the cord of the angled reinforcing member added at this time is orthogonal to the cord of the spiral belt.

  Further, the angled reinforcing member to be added may be added to the outer side in the tire radial direction of the spiral belt, or may be added to the inner side in the tire radial direction. When two angled reinforcing members are added, the angled reinforcing members may be arranged so as to sandwich the spiral belt.

  A pneumatic tire for a motorcycle according to claim 2 of the present invention includes a bead core embedded in a pair of left and right bead portions, a toroidal shape extending from one bead portion to the other bead portion, and an end portion wound around the bead core. And at least two carcass made of at least one carcass ply locked to the bead core and a plurality of cords arranged outside the carcass in the tire radial direction and arranged parallel to each other. A cross belt layer composed of crossed belt plies in which the belt plies adjacent to each other and the inclination directions of the cords with respect to the tire equatorial plane are opposite to each other, and on the outer side in the tire radial direction of the cross belt layer A pneumatic tire for a motorcycle including a tread portion disposed in the tire equator in a cross section in the tire width direction. When the tread tread distance between the tread and the tread end is L, the first position of L / 3 along the tread tread from the tread end to the tire equator side, and from the tire equator to the tread end side At least one angled reinforcing member in which a plurality of cords having an angle with respect to the tire circumferential direction of 0 to 90 degrees are embedded in the covering rubber between the second position of L / 6 along the tread surface. It is arranged.

Next, the function and effect of the pneumatic tire for a motorcycle according to claim 2 will be described.
Claim 2 stipulates that in a conventional cross belt structure that does not use a spiral belt, the position equivalent to that of Claim 1 (the region between points P and Q) is reinforced with an angled reinforcing member. In addition, since the effect obtained by Claim 2 is the same as the effect obtained by Claim 1, description is abbreviate | omitted. Moreover, the positional relationship of each point of this claim is shown in FIG.

The effects of items different from those of claim 1 will be described below.
The angles of the cords of the angled reinforcing members with respect to the tire circumferential direction included 0 to 90 degrees and 0 degrees. This is because the cord of the angled reinforcement member with the cord angle of 0 degrees is added to the cord of the belt ply of the crossing belt layer when an angled reinforcement member with a cord angle of 0 degrees with respect to the tire circumferential direction is added. This is because the cord of the belt ply crosses the belt ply and has a reinforcing effect. The upper limit of the angle is 90 degrees, and even in the case of 90 degrees, it intersects with the intersecting belt layer.

  The pneumatic tire for a motorcycle according to claim 3 of the present invention is the pneumatic tire for a motorcycle according to claim 1 or 2, wherein the angled reinforcing member includes two of the angled reinforcements in which the cords cross each other. It consists of a member, It is characterized by the above-mentioned.

  Next, functions and effects of the pneumatic tire for a motorcycle according to claim 3 will be described. When two angled reinforcing members are added, the belt rigidity increases more when the two members are crossed with each other than when they are not crossed.

  A pneumatic tire for a motorcycle according to a fourth aspect of the present invention is the pneumatic tire for a motorcycle according to any one of the first to third aspects, wherein the width of the angled reinforcing member is set to W in the cross section in the tire width direction. In this case, L / 6 ≦ W is satisfied.

  Next, functions and effects of the pneumatic tire for a motorcycle according to claim 4 will be described. If the width W of the angled reinforcing member is L / 6> W, the reinforcing effect is small, and the increase in the lateral rigidity of the tire is low, so that the effect of improving the steering stability during turning when the vehicle body is largely tilted is small. Therefore, the width W of the angled reinforcing member preferably satisfies L / 6 ≦ W. In the present invention, the upper limit value of W is the distance L / 2 of the tread surface between the first position and the second position.

  A pneumatic tire for a motorcycle according to claim 5 of the present invention includes a bead core embedded in a pair of left and right bead portions, a toroid shape extending from one bead portion to the other bead portion, and an end portion wound around the bead core. A carcass composed of at least one carcass ply in which a plurality of cords locked to the bead core are embedded in the covering rubber, and a plurality of cords arranged on the outer side in the tire radial direction of the carcass in the covering rubber. A pneumatic tire for a motorcycle, comprising: a belt layer comprising at least one belt ply embedded in the tire; and a tread portion disposed radially outward of the belt layer, wherein When the tread tread distance between the tread and the tread edge is L, the first position of L / 3 along the tread tread from the tread edge to the tire equator side And a thickness of 0.5 to 4 mm so as to contact at least one of the belt layer and the carcass between the tire equatorial plane and the second position of L / 6 along the tread surface from the tread end side. And at least one reinforced rubber member having a hardness equal to or higher than that of the harder one of the covering rubber of the carcass ply cord and the covering rubber of the belt ply cord.

Next, functions and effects of the pneumatic tire for a motorcycle according to claim 5 will be described.
In Claim 5, it was prescribed | regulated that the position (area | region between P point and Q point) equivalent to Claim 1 in a tire was reinforced with a reinforcement rubber member. In addition, since the effect obtained in Claim 4 is the same as the effect obtained in Claim 1, description is abbreviate | omitted. Moreover, the positional relationship of each point of this claim is shown in FIG.

The effects of items different from those of claim 1 will be described below.
Further, it is not necessary to dispose the reinforcing rubber member in the entire range between the point P and the point Q to increase the rigidity of the belt, and a sufficient effect can be obtained if the rigidity is increased in a part between them. Of course, it does not matter if the rigidity is increased for everything in between.
The belt layer may be a spiral belt wound in the tire equator direction, or may be two or three crossing belt layers.

  The positional relationship between the reinforcing rubber member to be added, the belt layer, and the carcass is designated to add the reinforcing rubber member so as to be in contact. That is, the reinforcing rubber member is between the belt layer and the tread, and when the belt layer is composed of two or more belt plies, between the belt ply and the belt ply, between the belt layer and the carcass, and two carcasses. In the case of the carcass ply described above, it may be disposed between the carcass ply and the carcass ply or on the inner side in the tire radial direction of the carcass. Two or more reinforcing rubber members may be arranged. In addition, the reinforcing rubber member is arranged so as to be in contact with these cords because the reinforcing rubber member having a hardness equal to or higher than that of the rubber covering the cord is present, and the arrangement position of the cord is shifted. This is because the aim is to increase the rigidity of the cord. Of course, when the carcass is arranged in the radial direction of the tire or between the belt layer and the tread portion, the arrangement position of the cord may not be changed, but in this case, the structure body depends on the hardness of the reinforcing rubber member itself. Is reinforced.

  The thickness of the reinforced rubber member was 0.5 to 4 mm. This is because if the thickness is less than 0.5 mm, the reinforcing effect of the reinforcing rubber member cannot be sufficiently obtained. Further, in the case of a member thicker than 4 mm, rubber thicker than 4 mm flows to other parts in the vulcanization process, which is difficult to manufacture. Therefore, the thickness of the reinforcing rubber member is preferably 0.5 to 4 mm.

  A pneumatic tire for a motorcycle according to claim 6 of the present invention is the pneumatic tire for motorcycle according to claim 5, wherein L / 6 ≦ W when the width of the reinforcing rubber member is W in the cross section in the tire width direction. It is characterized by satisfying.

  Next, functions and effects of the pneumatic tire for a motorcycle according to claim 6 will be described. If the width W of the reinforcing rubber member is L / 6> W, the reinforcing effect is small, and the increase in the lateral rigidity of the tire is low, so that the effect of improving the steering stability when turning the vehicle body is greatly reduced. Therefore, the width W of the reinforcing rubber member preferably satisfies L / 6 ≦ W. In the present invention, the upper limit value of W is the distance L / 2 of the tread surface between the first position and the second position.

  The pneumatic tire for a motorcycle according to the present invention maintains riding comfort performance and is excellent in steering stability performance when turning the vehicle body greatly down.

[First Embodiment]
Next, a first embodiment of a pneumatic tire for a motorcycle according to the present invention will be described with reference to FIG. In addition, the tire size of the pneumatic tire 10 for two-wheeled vehicles of this embodiment shall be 190 / 50ZR17.
As shown in FIG. 1, a pneumatic tire 10 for a motorcycle includes a first carcass ply 12 and a second carcass ply 14 in which a cord extending in a direction intersecting the tire equatorial plane CL is embedded. 16 is provided.

(Carcass)
Both ends of the first carcass ply 12 and the second carcass ply 14 are wound around the bead core 20 embedded in the bead portion 18 from the tire inner side toward the outer side.

  The first carcass ply 12 is formed by embedding a plurality of radially extending cords (for example, organic fiber cords such as nylon) in parallel in the covering rubber. In the present embodiment, the first carcass ply 12 has a tire equatorial plane CL. The angle of the cord with respect to the tire equatorial plane CL is set to 70 degrees. The second carcass ply 14 is also one in which a plurality of radially extending cords (for example, organic fiber cords such as nylon) are embedded in parallel in the covering rubber, and in this embodiment, the tire equatorial plane CL The angle of the cord with respect to the tire equatorial plane CL is set to 70 degrees. Note that the cord of the first carcass ply 12 and the cord of the second carcass ply 14 intersect each other and are inclined in opposite directions with respect to the tire equatorial plane CL.

(Spiral belt layer)
A spiral belt layer 22 is provided outside the carcass 16 in the tire radial direction. The spiral belt layer 22 is formed by, for example, spiraling a long rubber-coated cord in which one cord is coated with an unvulcanized coating rubber, or a belt-like ply in which a plurality of cords are coated with an unvulcanized coating rubber. The angle of the cord with respect to the tire circumferential direction is approximately 0 degrees (about 0 to 3 degrees). The cord of the spiral belt layer 22 may be an organic fiber cord or a steel cord.

  The spiral belt layer 22 of the present embodiment is formed by spirally forming a belt-like body in which two parallel cords (steel cords obtained by twisting steel single wires having a diameter of 0.21 mm in 1 × 3 type) are embedded in a covering rubber. It is formed by winding in the tire rotation axis direction. Note that the cord driving interval in the spiral belt layer 22 of the present embodiment is 30/50 mm.

(Inclined belt layer, tread)
Between the spiral belt layer 22 and the carcass 16, an inclined belt layer 24 disposed at a predetermined position is disposed, and a tread rubber 30 forming a tread 28 is disposed outside the spiral belt layer 22 in the tire radial direction. Has been. In addition, the thickness of the tread rubber 30 of the present embodiment is uniformly 8 mm.

  As shown in FIG. 1, in the cross section in the tire radial direction, the intersection of the tread 28 and the tire equatorial plane CL is point C, the end of the tread 28 is point A, and the entire width of the tread 28 (along the tread 28 tread). The distance to be measured) is TW, half of the total width TW of the tread 28 (the distance between the point C and the point A) is L (L = 0.5 TW), and the point A is pointed from the point A to the point C along the tread 28 tread surface. A position L / 3 away from this point is designated P point, and a position L / 6 away from point C toward point A along the tread 28 tread surface is designated Q point.

  Here, the inclined belt layer 24 is preferably disposed between the point P and the point Q. Further, the inclined belt layer 24 is formed by embedding a plurality of cords in parallel in a covered rubber, and the cord may be an organic fiber cord or a steel cord. Further, the cord of the inclined belt layer 24 is preferably set at an angle of 30 to 90 degrees with respect to the tire circumferential direction (or the tire equatorial plane CL). Moreover, although the inclined belt layer 24 of this embodiment is arrange | positioned at the tire radial direction inner side of the spiral belt layer 22, you may arrange | position at the tire radial direction outer side.

  Further, the inclined belt layer 24 may be configured by a plurality of inclined belt layers 24. For example, as in the present embodiment, if the inclined belt layer 24 is two inclined belt layers 24, the inclined belt layer 24 is directed outward in the tire radial direction. The first inclined belt layer 24 </ b> A and the second inclined belt layer 24 </ b> B are preferably formed so that the respective cords cross each other and are inclined in opposite directions with respect to the tire equatorial plane CL.

  In the tire width direction cross section, it is preferable that L / 6 ≦ W is satisfied, where W is the width of the inclined belt layer 24. When the inclined belt layer 24 is composed of a plurality of sheets, W is a range that is reinforced by the inclined belt layer.

As shown in FIG. 1, the belt layer of this embodiment is only the spiral belt layer 22 and the inclined belt layer 24, but other belt layers may be added.
Although the groove is not formed in the tread 28 shown in FIG. 1, the groove | channel for drainage required at the time of wet road surface travel may be formed.
In addition, since the full width TW of the tread 28 of this embodiment is 240 mm, L is 120 mm, the distance L / 6 between CQs is 20 mm, and the distance L / 3 between APs is 40 mm.

(Function)
In the pneumatic tire 10 for a motorcycle according to this embodiment, since the spiral belt layer 22 is provided on the outer side in the tire radial direction of the carcass 16, the rigidity in the tire circumferential direction of the tread 28 is increased, and the tire diameter of the tread 28 during high speed running is increased. The protrusion to the outside in the direction can be suppressed, and the high-speed durability is improved.

  Further, in the pneumatic tire 10 for a motorcycle according to the present embodiment, when turning with the vehicle body greatly tilted, that is, during cornering that requires a large lateral force, an area of L / 3 from the end portion (point A) of the tread 28 ( Rather than the area between point A and point P, that is, the contact area with the road surface at the time of turning when the vehicle body is greatly tilted, the rigidity of the area immediately adjacent to it (area between points P and Q) is inclined. By increasing the belt layer 24, the ground contact area can be maintained and the rigidity of the tire during turning can be increased, so that the steering stability performance during turning is improved.

  Further, during straight running, the tread 28 is grounded at a portion with low bending rigidity among the tread 28 reinforced only by the spiral belt layer 22 at the center in the tire width direction, so that ride comfort and vibration absorption during straight running are achieved. Will improve. Moreover, since a wide contact width can be ensured, the straight running performance can be improved.

  Therefore, by enhancing only the rigidity of the area immediately adjacent to the contact area with the road surface when turning the vehicle body, the vibration riding comfort performance during straight running is maintained and the steering stability performance during turning is excellent. .

  Further, since the cord of the spiral belt layer 22 has an angle with respect to the tire circumferential direction of approximately 0 degrees (about 0 to 3 degrees), in order to increase the belt rigidity, the cord angle with respect to the tire circumferential direction is The inclined belt layer 24 having an angle intersecting with the cord of the spiral belt layer 22 such as an angle of the cord of 30 to 90 degrees can obtain a higher effect than the addition of the 0-degree inclined belt layer 24. Here, the angle of the cord of the inclined belt layer 24 is set to 30 degrees or more when there is no angle difference of 30 degrees or more in consideration of crossing with the spiral belt layer 22 whose cord angle is 0 degree. This is because it does not function as a crossing belt layer. The upper limit is 90 degrees, and the cord of the inclined belt layer 24 and the cord of the spiral belt layer 22 added at this time are orthogonal to each other.

  When the two first inclined belt layers 24A and the second inclined belt layer 24B are provided between the point P and the point Q, when the two pieces are crossed with each other and the non-crossed ones are compared. In the case of the inclined belt layers that are crossed, the increase in belt rigidity is increased.

  If the width W of the inclined belt layer 24 is L / 6> W, the reinforcing effect is small and the increase in the lateral rigidity of the tire is low, so that the effect of improving the steering stability during turning when the vehicle body is largely tilted is small. Therefore, the width W of the inclined belt layer 24 preferably satisfies L / 6 ≦ W. In addition, the upper limit value of W in the present embodiment is the distance L / 2 of the tread surface of the tread 28 between the point P and the point Q.

[Second Embodiment]
Next, a second embodiment of the pneumatic tire for a motorcycle according to the present invention will be described with reference to FIG. The tire size of the pneumatic tire 10 for a motorcycle according to the present embodiment is 190 / 50ZR17 as in the first embodiment. In the pneumatic tire 10 for a motorcycle, as shown in FIG. 2, an intersecting belt layer 26 is disposed instead of the spiral belt layer 22, and the tire circumferences of the respective cords of the first carcass ply 12 and the second carcass ply 14 are arranged. The angle with respect to the direction is 90 degrees respectively, and the angle range with respect to the tire circumferential direction of each cord of the first inclined belt layer 24A and the second inclined belt layer 24B is 0 to 90 degrees. The configuration is different from that of the first embodiment, and the other configuration is the same as that of the first embodiment. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

(Carcass)
The first carcass ply 12 is formed by embedding a plurality of radially extending cords (for example, organic fiber cords such as nylon) in parallel in the covering rubber. In the present embodiment, the first carcass ply 12 has a tire equatorial plane CL. The angle of the cord with respect to the tire equatorial plane CL is set to 90 degrees. The second carcass ply 14 is also one in which a plurality of radially extending cords (for example, organic fiber cords such as nylon) are embedded in parallel in the covering rubber, and in this embodiment, the tire equatorial plane CL The angle of the cord with respect to the tire equatorial plane CL is set to 90 degrees.

(Intersection belt layer)
An intersecting belt layer 26 is disposed outside the carcass 16 in the tire radial direction.
The crossing belt layer 26 includes a first belt ply 26A and a second belt ply 26B.

  The first belt ply 26A is formed by embedding a plurality of cords (corresponding to a diameter of 0.7 mm in which aromatic polyamide fibers are twisted) in parallel in a coated rubber, in parallel. Then, the angle of the cord with respect to the tire equatorial plane CL at the tire equatorial plane CL is set to 24 degrees. The second belt ply 26B is also formed by embedding a plurality of cords (corresponding to a cord having a diameter of 0.7 mm in which aromatic polyamide fibers are twisted in this embodiment) in parallel in the covering rubber. Then, the angle of the cord with respect to the tire equatorial plane CL at the tire equatorial plane CL is set to 24 degrees.

  Note that the cord of the first belt ply 26A and the cord of the second belt ply 26B intersect with each other, and are inclined in opposite directions with respect to the tire equatorial plane CL. Further, the cord driving intervals in the first belt ply 26A and the second belt ply 26B in the present embodiment are 60/50 mm, respectively.

(Inclined belt layer, tread)
An inclined belt layer 24 disposed at a predetermined position and a tread rubber 30 forming a tread 28 are sequentially disposed on the outer side in the tire radial direction of the crossing belt layer 26. In addition, the thickness of the tread rubber 30 of the present embodiment is uniformly 8 mm.

In addition, the cord of the inclined belt layer 24 is preferably set to an angle of 0 to 90 degrees with respect to the tire circumferential direction.
Moreover, although the inclined belt layer 24 of this embodiment is arrange | positioned at the tire radial direction outer side of the crossing belt layer 26, you may arrange | position at the tire radial direction inner side.
As shown in FIG. 2, the belt layers of the present embodiment are only the cross belt layer 26 and the inclined belt layer 24, but other belt layers (for example, the spiral belt layer 22) may be added.

(Function)
In the pneumatic tire 10 for a motorcycle according to the present embodiment, the angle of the cord of the inclined belt layer 24 with respect to the tire circumferential direction includes 0 to 90 degrees and 0 degrees. This is because, when an inclined belt layer 24 (that is, a spiral belt) having a cord angle of 0 degrees is added to the crossing belt layer 26, the cord in the tire circumferential direction is the same as the cord of the crossing belt layer 26 having an angle with respect to the tire circumferential direction of 24 degrees. Since the crossing with the cord of the inclined belt layer 24 having an angle with respect to 24 degrees intersects, a reinforcing effect is obtained. The upper limit is 90 degrees, but the cords of the inclined belt layer 24 and the cords of the intersecting belt layer 26 are crossed even at 90 degrees.

[Third Embodiment]
Next, a third embodiment of the pneumatic tire for a motorcycle according to the present invention will be described with reference to FIG. The tire size of the pneumatic tire 10 for a motorcycle according to the present embodiment is 190 / 50ZR17 as in the first embodiment. As shown in FIG. 3, the pneumatic tire 10 for a motorcycle is different from the first embodiment in that a reinforcing rubber member is disposed instead of the inclined belt layer, and the others are the same as in the first embodiment. It is a configuration. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

(Reinforced rubber member, tread)
A reinforcing rubber member 38 disposed at a predetermined position is disposed between the spiral belt layer 22 and the carcass 16, and a tread rubber 30 that forms a tread 28 is disposed outside the spiral belt layer 22 in the tire radial direction. Has been. In addition, the thickness of the tread rubber 30 of the present embodiment is uniformly 8 mm.

  The reinforcing rubber member 38 is preferably disposed between the point P and the point Q. The reinforcing rubber member 38 preferably has a thickness of 0.5 to 4 mm. The reinforcing rubber member 38 is disposed on the outer side in the tire radial direction of the spiral belt layer 22, but may be in contact with at least one of the spiral belt layer 22 or the carcass 16.

  In the cross section in the tire width direction, it is preferable that L / 6 ≦ W is satisfied when the width of the reinforcing rubber member 38 is W. When a plurality of reinforcing rubber members 38 are formed, W is a range that is reinforced by the reinforcing rubber member.

Also, a configuration in which a plurality of reinforcing rubber members 38 are provided may be employed. For example, if two reinforcing rubber members are provided, the first reinforcing rubber member 38A and the second reinforcing rubber are provided toward the outer side in the tire radial direction. The rubber member 38B may be used.
The reinforcing rubber member 38 preferably has a hardness equal to or higher than that of the higher-coating rubber of the cord covering rubber of the carcass 16 and the cord covering rubber of the spiral belt layer 22.
As shown in FIG. 3, the belt layer of this embodiment is only the spiral belt layer 22 and the reinforcing rubber member 38, but other belt layers may be added.

(Function)
In the pneumatic tire 10 for a motorcycle according to the present embodiment, the positional relationship between the reinforcing rubber member 38 to be added and the spiral belt layer 22 or the carcass 16 is specified to add the reinforcing rubber member 38 so as to be in contact. That is, the reinforcing rubber member 38 is provided between the spiral belt layer 22 and the tread 28. When the spiral belt layer 22 includes two or more spiral belts, the reinforcing rubber member 38 is provided between the spiral belt and the spiral belt. When the carcass 16 is composed of two or more carcass plies between the first carcass ply 12 and the second carcass ply 14 and between the first carcass ply 14 and the inner side in the tire radial direction of the carcass 16. That's fine. Two or more reinforcing rubber members 38 may be arranged. The reinforcing rubber member 38 is arranged so as to be in contact with these cords because the reinforcing rubber member having a hardness equal to or higher than that of the rubber covering the cords is present, and the arrangement position of the cords is shifted. This is because the aim is to increase the rigidity of the. Of course, when the carcass 16 is arranged in the tire radial direction or between the spiral belt layer 22 and the tread 28, the arrangement position of the cord may not be changed, but in this case, the reinforcing rubber member 38 itself has a hard position. Thus, the structure is reinforced.

  The thickness of the reinforcing rubber member 38 was 0.5 mm or more. This is because if the thickness is less than 0.5 mm, a sufficient reinforcing effect cannot be obtained. Also, it was within 4 mm. This is due to the manufacturing reason that a member thicker than 4 mm is difficult to manufacture because rubber thicker than 4 mm flows to other parts in the vulcanization process.

  If the width W of the reinforced rubber member 38 is L / 6> W, the increase in the lateral rigidity of the tire is low, and the effect of improving the steering stability during turning when the vehicle body is largely tilted is small. Therefore, the width W of the reinforcing rubber member 38 preferably satisfies L / 6 ≦ W. In addition, the upper limit value of W in the present embodiment is the distance L / 2 of the tread surface of the tread 28 between the point P and the point Q.

[Fourth Embodiment]
Next, a fourth embodiment of the pneumatic tire for a motorcycle of the present invention will be described with reference to FIG. The tire size of the pneumatic tire 10 for a motorcycle according to the present embodiment is 190 / 50ZR17 as in the first embodiment. In the pneumatic tire 10 for a motorcycle, as shown in FIG. 4, the crossing belt layer 26 of the pneumatic tire for a motorcycle according to the second embodiment instead of the spiral belt layer 22 of the pneumatic tire for a motorcycle according to the third embodiment. Is different from the third embodiment, and the other configuration is the same as that of the third embodiment. In addition, the same code | symbol is attached | subjected to the same structure as 3rd Embodiment, and the description is abbreviate | omitted.

(Function)
In the pneumatic tire 10 for a motorcycle according to the present embodiment, even when the crossing belt layer 26 is used for the belt layer of the pneumatic tire for a motorcycle according to the third embodiment, the same effect as that of the third embodiment is obtained. Obtainable.

(Test Example 1)
In order to confirm the performance improvement effect of the pneumatic tire for a motorcycle according to the present invention, three types of pneumatic tires for a motorcycle according to the first embodiment of the present invention and two types of pneumatic tires for a motorcycle according to a comparative example were used. We prepared and conducted a pilot performance comparison test using an actual vehicle. Since these pneumatic tires for motorcycles (hereinafter simply referred to as tires) were rear tires, only the rear tires were replaced, and actual vehicle tests were performed. The front tire was always fixed with a conventional tire. The evaluation method is as follows.

  In the test, the test tire was mounted on a 1000cc sports-type motorcycle (hereinafter simply referred to as a motorcycle), and the vehicle was driven on the test course. The evaluation was centered on ride comfort performance and steering stability performance, and was comprehensively evaluated by a 10-point method based on the feeling of a test rider. The test rider's evaluation comments are also included and the results are shown below.

(Comparative Example 1)
Structure: The tire of Comparative Example 1 (hereinafter simply referred to as Comparative Example 1) is a tire obtained by removing the inclined belt layer 24 from the tire of the first embodiment.
Ride comfort when going straight: 8 points Braking and traction performance when going straight: 7 points Steering stability performance when turning: 4 points Overall points of steering stability performance: 5 points Rider Comments: Riding comfort when tires feel soft and straight Is good. There is a feeling that the tires are crushed during traction, and the rear of the car body sinks, but at a level that does not matter, traction and braking are good. When turning, the tires are weak in the lateral direction and feel the weakness of the tires. There is a feeling of crumpling when a large lateral force is applied.

(Comparative Example 2)
Structure: The tire of Comparative Example 2 (hereinafter simply referred to as Comparative Example 2) is a tire in which the spiral belt layer 22 of Comparative Example 1 is doubled.
Ride comfort when going straight: 3 points Brake and traction performance when going straight: 5 points Steering stability performance during turning: 6 points Overall points of overall steering stability performance: 4 points Rider Comments: Tires are hard anyway. The vehicle bounces on rough roads. The ride comfort during straight running is poor, and it is easy to idle during traction and driving. When turning, the tire has strong lateral rigidity, but the tire is easy to slide sideways and has a low grip.

Example 1
Structure: For the tire of Example 1 shown in FIG. 6 (hereinafter simply referred to as Example 1), a point 50 mm away from the point A on the tread edge to the point C on the tire equatorial plane CL along the tread surface. In addition, one first inclined belt layer 24A having a width of 30 mm is disposed, and the outer side of the first inclined belt layer 24A in the tire radial direction is located at a position 40 mm away from point A to point C along the tread surface. In addition, one second inclined belt layer 24B having a width of 30 mm is disposed. The point P is a position 40 mm away from the point A, and the point Q is a position 20 mm away from the point C. Therefore, the inclined belt layer 24 of Example 1 is disposed between the points P and Q. ing. The first inclined belt layer 24A and the second inclined belt layer 24B are coated rubber in which cords made by twisting aromatic polyamide (Kevlar: trade name) to a diameter of 0.7 mm are arranged in parallel at an interval of 50/50 mm. It is buried inside. Further, the cords of the first inclined belt layer 24A and the cords of the second inclined belt layer 24B have an angle of 45 degrees with respect to the tire circumferential direction, and the respective cords intersect each other. An additional position of the first inclined belt layer 24 </ b> A and the second inclined belt layer 24 </ b> B is between the spiral belt layer 22 and the tread rubber 30.
Ride comfort when traveling straight: 6 points Braking and traction performance when traveling straight: 9 points Steering stability during turning: 9 points Overall points of overall steering stability: 9 points Rider Comments: Riding comfort is better than Comparative Example 1 Hard but not bad. The tires are firm even during traction, and you can feel the driving force. Even when turning, the tires are stiff against lateral deformation, stable, and have a grip. Steering stability is generally excellent.

(Example 2)
Structure: For the tire of Example 2 shown in FIG. 7 (hereinafter simply referred to as Example 2), a point 50 mm away from the point A on the tread edge to the point C on the tire equatorial plane CL is the base point. In addition, one first inclined belt layer 24A having a width of 30 mm is disposed, and the outer side of the first inclined belt layer 24A in the tire radial direction is located at a position 40 mm away from point A to point C along the tread surface. In addition, one second inclined belt layer 24B having a width of 30 mm is disposed. Similar to the first embodiment, the inclined belt layer 24 of the second embodiment is disposed between the point P and the point Q. The first inclined belt layer 24A and the second inclined belt layer 24B are coated rubber in which cords made by twisting aromatic polyamide (Kevlar: trade name) to a diameter of 0.7 mm are arranged in parallel at an interval of 50/50 mm. It is buried inside. In addition, the cord of the first inclined belt layer 24A has an angle of 90 degrees with respect to the tire circumferential direction, and the cord of the second inclined belt layer 24B has an angle of 45 degrees with respect to the tire circumferential direction. Intersect each other. An additional position of the first inclined belt layer 24 </ b> A and the second inclined belt layer 24 </ b> B is between the spiral belt layer 22 and the carcass 16.
Ride comfort when traveling straight: 6 points Braking and traction performance when traveling straight: 9 points Steering stability during turning: 9 points Overall points for overall steering stability: 9 points Rider Comments: Same feeling as Example 1. Very good handling stability.

(Example 3)
Structure: The tire of Example 3 shown in FIG. 8 (hereinafter simply referred to as Example 3) is the first inclined belt of the first inclined belt layer 24A and the second inclined belt layer 24B of Example 1. A type in which the layer 24A is added as the inclined belt layer 24. The arrangement, material, and angle of the cord with respect to the tire circumferential direction are the same as those in the first embodiment.
Ride comfort when going straight: 7 points Brake and traction performance when going straight: 8 points Steering stability performance when turning: 8 points Overall points of overall steering stability performance: 8 points Rider Comments: Riding comfort is harder than the comparative example However, it is better than Example 1. The tires are firm even during traction, and you can feel the driving force. Even when turning, the tires are stiff against lateral deformation, stable, and have a grip. The tire feels softer than Example 1.

(Verification of results)
Consider the results of Comparative Example 1, Comparative Example 2, and Examples 1 to 3. If only one spiral belt layer 22 is used, the tires are soft and comfortable to ride, but there is a feeling of crunch when turning and the bike cannot be stably cornered. If the spiral belt layer 22 is simply doubled, the tire becomes hard. Ride comfort is impaired. Although the tire has rigidity when turning, the spiral belt layer 22 is doubled even in the tread shoulder portion, so the out-of-plane rigidity of the belt increases and the belt becomes difficult to deform (the belt deforms following the road surface). (Because it is not possible), the contact area with the road surface decreases, the grip force decreases, and it becomes easier to slide sideways. On the other hand, it can be seen that Examples 1 to 3 can increase the firmness and stability of the tire when turning without impairing the ride comfort performance when traveling straight ahead. The difference between Example 1 and Example 3 was that in Example 1, two sheets of the first inclined belt layer 24A and the second inclined belt layer 24B were added between PQ. In Example 3, because only the first inclined belt layer 24A is added, it is considered that Example 3 has a lower reinforcement ratio than Example 1.

(Test Example 2)
Tests similar to Test Example 1 described above are performed on the tires of Examples 4 and 5 and Comparative Example 3 according to the second embodiment. The results are shown below.
(Comparative Example 3)
Structure: The tire of Comparative Example 3 (hereinafter simply referred to as Comparative Example 3) is a tire obtained by removing the inclined belt layer 24 from the tire of the second embodiment.
Ride comfort when going straight: 8 points Braking and traction performance when going straight: 5 points Steering stability performance when turning: 4 points Overall points of steering stability performance: 6 points Rider Comments: Riding comfort when tires feel soft and straight Is good. However, the tire feels crushed during traction, and the rear of the vehicle sinks. When turning, the tires are weak in the lateral direction and feel the weakness of the tires. There is a feeling of crumpling when a large lateral force is applied.

Example 4
Structure: In the tire of Example 4 shown in FIG. 9 (hereinafter simply referred to as Example 4), a point 50 mm away from the point A of the tread end to the point C on the tire equatorial plane CL along the tread surface. In addition, one first inclined belt layer 24A having a width of 30 mm is disposed, and the outer side of the first inclined belt layer 24A in the tire radial direction is located at a position 40 mm away from point A to point C along the tread surface. In addition, one second inclined belt layer 24B having a width of 30 mm is disposed. Since the point P is a position 40 mm away from the point A and the point Q is a position 20 mm away from the point C, the inclined belt layer 24 of Example 4 is disposed between the points P and Q. ing. The first inclined belt layer 24A and the second inclined belt layer 24B are coated rubber in which cords made by twisting aromatic polyamide (Kevlar: trade name) to a diameter of 0.7 mm are arranged in parallel at an interval of 50/50 mm. It is buried inside. Further, the cords of the first inclined belt layer 24A and the cords of the second inclined belt layer 24B have an angle of 60 degrees with respect to the tire circumferential direction, and the respective cords intersect each other. An additional position of the first inclined belt layer 24 </ b> A and the second inclined belt layer 24 </ b> B is between the crossing belt layer 26 and the carcass 16.
Ride comfort when going straight: 7 points Brake and traction performance when going straight: 6 points Steering stability during turning: 7 points Overall points of overall steering stability: 7 points Rider Comments: Tires are solid. The braking force from the road surface is transmitted during traction and driving. When turning, the tire has a strong lateral stiffness and improved grip.

(Example 5)
Structure: The tire of Example 5 shown in FIG. 10 (hereinafter simply referred to as Example 5) has a width of 30 mm from the position 50 mm away from the point A on the tread edge to the point C on the tire equatorial plane CL. One inclined belt layer 24 is disposed. The inclined belt layer 24 of Example 5 is disposed between the P point and the Q point. The inclined belt layer 24 is a cord in which an aromatic polyamide (Kevlar: trade name) is twisted to have a diameter of 0.7 mm, and the cords are arranged in parallel at an interval of 50/50 mm and embedded in the coated rubber. The cord of the inclined belt layer 24 is substantially parallel to the tire circumferential direction (spiral belt layer) and is wound around the crossing belt layer 26. The additional position of the inclined belt layer 24 is between the crossing belt layer 26 and the carcass 16.
Ride comfort when going straight: 7 points Braking and traction performance when going straight: 6 points Steering stability during turning: 8 points Overall points of overall steering stability: 7 points Rider Comments: Tires are solid. Slightly better than Example 4 in steering stability during cornering.

(Verification of results)
Consider the results of Comparative Example 3 and Examples 4 and 5. The crossed belt layer 26 composed of the two first belt plies 26A and the second belt ply 26B of Comparative Example 3 has a soft tire and good ride comfort, but has a feeling of crumble during turning, and a motorcycle. However, it was difficult to corner stably. In Examples 4 and 5, it can be seen that a firm feeling and stability of the tire during turning can be increased without impairing the ride comfort performance when traveling straight.

(Test Example 3)
Tests similar to Test Example 1 described above are performed on the tires of Examples 6 and 7 and Comparative Example 4 according to the third embodiment. The results are shown below.
(Comparative Example 4)
Structure: The tire of Comparative Example 4 (hereinafter simply referred to as Comparative Example 4) is a tire obtained by removing the reinforcing rubber member 38 from the tire of the third embodiment.
Ride comfort when going straight: 8 points Braking and traction performance when going straight: 6 points Steering stability performance when turning: 5 points Overall points of overall steering stability performance: 6 points Rider Comments: Ride comfort when tires feel soft and straight Is good. When turning, the tire is not sufficiently rigid in the lateral direction, and the lateral movement of the tire is large and feels weak. There is a feeling of crumpling when a large lateral force is applied.

(Example 6)
Structure: In the tire of Example 6 shown in FIG. 11 (hereinafter simply referred to as Example 6), a position 60 mm away from the point A on the tread edge to the point C on the tire equator CL along the tread surface is a base point. In addition, one reinforcing rubber member 38 having a width of 10 mm and a thickness of 2 mm is disposed between the first carcass ply 12 and the second carcass ply 14. Further, the reinforcing rubber member 38 of Example 6 is disposed between the point P and the point Q. The material of the reinforcing rubber member 38 is the same as the coating rubber member of the carcass ply cord. By adding the reinforcing rubber member 38, the first carcass ply 12 on the innermost side in the tire radial direction moved toward the inner surface of the tire to form a convex shape.
Ride comfort when traveling straight: 7 points Braking and traction performance when traveling straight: 7 points Steering stability during turning: 7 points Overall points for overall steering stability: 7 points Rider Comments: Tires are harder than Comparative Example 4, Stability increased during straight running, and traction and brakes increased stability. When turning, I feel that the rigidity of the tire has increased in the lateral direction.

(Example 7)
Structure: In the tire of Example 7 shown in FIG. 12 (hereinafter simply referred to as Example 7), a point 60 mm away from the point A on the tread edge to the point C on the tire equatorial plane CL along the tread surface. In addition, a trapezoidal reinforcing rubber member 38 having a width of 10 mm and a thickness of 4 mm is disposed. Further, the reinforcing rubber member 38 of Example 6 is disposed between the point P and the point Q. The material of the reinforcing rubber member 38 is the same as the coating rubber of the cord of the spiral belt layer 22. The shape of the reinforced rubber member 38 is trapezoidal, the lower base (surface in the tire radial direction) is 10 mm, the upper base (surface in the tire radial direction) is 6 mm, the height is 4 mm, and the upper base is the spiral belt layer 22. The lower bottom is in contact with the tread rubber 30. By adding this reinforcing rubber member 38, the arrangement of the cords of the spiral belt layer 22 was depressed inward in the tire radial direction. Accordingly, the first carcass ply 12 and the second carcass ply 14 are also recessed, and the spiral belt layer 22 and the carcass 16 are bent in the tire width direction at the additional position of the reinforcing rubber member 38. The additional position of the upper base of the reinforced rubber member 38 is 12 mm from the tread.
Riding comfort: 6 points Braking, traction performance when going straight: 8 points Steering stability performance during turning: 9 points Overall points of overall steering stability performance: 8 points Rider Comments: Tires are clearly harder than Comparative Example 4 However, stability increased when driving straight, and traction and braking performance improved. Steering stability is improved. When turning, it seems that the lateral rigidity of the tire has become very strong and the grip is high.

(Verification of results)
Consider the results of Comparative Example 4 and Examples 6 and 7. If only one spiral belt layer 22 is used, the tires are soft and comfortable to ride, but there is a feeling of crunching when turning, and the bike cannot be stably cornered. On the other hand, in Examples 6 and 7, although the riding comfort performance when going straight ahead tends to be slightly hard, the tire feels firm and the traction performance and braking performance when going straight are improved. . In addition, the tire has a sense of rigidity during turning, and the lateral movement of the tire is suppressed, providing a sense of stability and increasing the grip. In Example 6 and Example 7, Example 7 is superior in steering stability performance. In Example 7, a convex portion is formed in the tire width direction of the spiral belt layer 22. It seems that the part has exhibited a strong rigidity against out-of-plane bending so that the crease of the origami is difficult to bend, and has brought out an effect more than simply adding rubber.

(Test Example 4)
In order to confirm the performance improvement effect of the motorcycle tire of the present invention, three types of pneumatic tires for motorcycles of examples according to the fourth embodiment of the present invention and one type of pneumatic tire for motorcycles of comparative examples are prepared. A pilot performance comparison test using an actual vehicle was conducted. Since these tires were rear tires, only the rear tires were replaced and actual vehicle tests were performed. The front tire was always fixed with a conventional tire. The evaluation method is as follows.

  In the test, the test tire was mounted on a 1000cc motorcycle and the vehicle was driven on the circuit course, and the lap time was measured for 10 laps. In addition, the steering stability performance was evaluated by a 10-point method using a test rider feeling. The test rider's evaluation comments are also included and the results are shown below.

(Comparative Example 5)
Structure: The tire of Comparative Example 5 (hereinafter simply referred to as Comparative Example 5) is a tire obtained by removing the reinforcing rubber member 38 from the tire of the fourth embodiment.
10 lap average lap time: 48 seconds 3
Overall points of overall steering stability performance: 6 rider Comments: The tires feel soft, the tires feel crushed during traction, and the rear of the vehicle sinks. When turning, the tires feel weak due to insufficient lateral rigidity. There is a feeling of crumpling when a large lateral force is applied. In particular, when the vehicle body is greatly tilted like a hairpin curve at low speed, the lateral movement of the tire is large and the vehicle body is not stable, so the timing for opening the accelerator tends to be delayed and time loss tends to occur.

(Example 8)
Structure: The tire of Example 8 shown in FIG. 13 (hereinafter simply referred to as Example 8) is located at a position 50 mm away from the point A on the tread edge to the point C on the tire equator CL along the tread surface. Further, one reinforcing rubber member 38 having a width of 30 mm and a thickness of 1 mm is disposed between the crossing belt layer 26 and the carcass 16. Further, the reinforcing rubber member 38 of Example 6 is disposed between the point P and the point Q. The material of the reinforcing rubber member 38 is the same as the bead filler rubber, and the bead filler rubber has twice the hardness of the tread rubber 30.
10 lap average lap time: 47 seconds 4
Overall points of steering stability performance: 8 points Rider comment: The tire has a sense of rigidity. Tires will not collapse during traction, and the vehicle will stabilize when the accelerator is opened. When turning, the lateral movement of the tires became smaller, and the car body became more stable. Increased cornering speed.

Example 9
Structure: The tire of Example 9 shown in FIG. 14 (hereinafter simply referred to as Example 9) is located at a position 50 mm away from the point A on the tread edge to point C on the tire equatorial plane CL along the tread surface. In addition, one reinforcing rubber member 38 having a width of 30 mm and a thickness of 1 mm is disposed between the first belt ply 26A and the second belt ply 26B. Further, the reinforcing rubber member 38 of Example 6 is disposed between the point P and the point Q. The material of the reinforcing rubber member 38 is the same as that in the eighth embodiment.
10 lap average lap time: 47 seconds 2
Overall points of overall steering stability performance: 8 points Rider Comments: Same feeling as Example 8.

(Example 10)
Structure: The tire of Example 10 shown in FIG. 15 (hereinafter simply referred to as Example 10) has a width of 30 mm and a thickness of 1 mm inside the first carcass ply 12 on the innermost side in the tire radial direction of Example 9. Another reinforcing rubber member 38 is additionally arranged. The material of the reinforcing rubber member 38 is the same as that in the ninth embodiment.
10 lap average lap time: 46 seconds 8
Overall points of overall steering stability performance: 9 points Rider Comments: The best grip strength tested. The tire has a feeling of rigidity. Tires will not collapse during traction, and the vehicle will stabilize when the accelerator is opened. When turning, the lateral movement of the tire is very small, and the vehicle body can be kept stable. I felt the overall grip increased.

(Verification of results)
Consider the results of Comparative Example 5 and Examples 8, 9 and 10. With only the two crossing belts of Comparative Example 5, the tires were soft and there was a feeling of crunching when turning, making it difficult for the motorcycle to stably corner. In Examples 8, 9 and 10, the lateral rigidity at the time of turning of the tire increased, so that the vehicle could be stably driven and the time was improved. In particular, in Example 10, since the two reinforcements are used, it can be seen that the firm feeling and stability of the tire can be increased.

It is sectional drawing along the rotating shaft of the pneumatic tire for two-wheeled vehicles which concerns on 1st Embodiment. It is sectional drawing along the rotating shaft of the pneumatic tire for two-wheeled vehicles which concerns on 2nd Embodiment. It is sectional drawing along the rotating shaft of the pneumatic tire for motorcycles concerning 3rd Embodiment. It is sectional drawing along the rotating shaft of the pneumatic tire for two-wheeled vehicles which concerns on 4th Embodiment. (A) It is sectional drawing of the pneumatic tire for two-wheeled vehicles when the vehicle body is not inclined (camber angle is 0 degree | times), and a grounding shape figure. (B) It is sectional drawing of the pneumatic tire for two-wheeled vehicles when a vehicle body is greatly inclined (camber angle is about 45 degree | times), and a contact shape figure. 3 is a cross-sectional view of the pneumatic tire for a motorcycle according to Comparative Example 1 along the rotation axis. FIG. 6 is a cross-sectional view of a pneumatic tire for a motorcycle according to Comparative Example 2 along the rotation axis. FIG. 6 is a cross-sectional view of the pneumatic tire for a motorcycle according to Comparative Example 3 along the rotation axis. FIG. 6 is a cross-sectional view of a pneumatic tire for a motorcycle of Comparative Example 4 along the rotation axis. FIG. 6 is a cross-sectional view of a pneumatic tire for a motorcycle of Comparative Example 5 along the rotation axis. FIG. 10 is a cross-sectional view of a pneumatic tire for a motorcycle according to Comparative Example 6 along the rotation axis. FIG. 10 is a cross-sectional view of a pneumatic tire for a motorcycle according to Comparative Example 7 along the rotation axis. FIG. 10 is a cross-sectional view of the pneumatic tire for a motorcycle of Comparative Example 8 along the rotation axis. FIG. 10 is a cross-sectional view of the pneumatic tire for motorcycles of Comparative Example 9 along the rotation axis. FIG. 12 is a cross-sectional view of the pneumatic tire for a motorcycle according to Comparative Example 10 along the rotation axis. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire for motorcycles 16 Carcass 18 Bead part 20 Bead core 22 Spiral belt layer 24 Inclined belt layer (An angled reinforcement member)
26 Cross belt layer 28 Tread 38 Reinforced rubber member P First position Q Second position

Claims (6)

A bead core embedded in a pair of left and right bead parts;
A carcass composed of at least one carcass ply that spans from one bead portion to the other bead portion in a toroidal shape, and an end portion is wound around the bead core and locked to the bead core;
At least one spiral belt formed by spirally winding a belt-shaped rubber-coated cord, which is disposed on the outer side in the tire radial direction of the carcass and in which one or a plurality of parallel cords are embedded in a coated rubber;
A tread portion disposed on the outer side in the tire radial direction of the spiral belt, and a pneumatic tire for a motorcycle,
In the cross section in the tire width direction, when a tread surface distance between the tire equator surface and the tread edge is L, a first position of L / 3 along the tread surface from the tread edge to the tire equator surface side; A plurality of cords with an angle of 30 to 90 degrees with respect to the tire circumferential direction is embedded in the coated rubber between the tire equatorial plane and the second position of L / 6 along the tread surface from the tread end side. A pneumatic tire for a motorcycle, comprising at least one angled reinforcing member arranged. A bead core embedded in a pair of left and right bead parts;
A carcass composed of at least one carcass ply that spans from one bead portion to the other bead portion in a toroidal shape, and an end portion is wound around the bead core and locked to the bead core;
The tire equatorial plane of the cord is composed of at least two belt plies that are arranged on the outer side in the tire radial direction of the carcass and in which a plurality of cords arranged in parallel to each other are embedded in a covering rubber. An intersecting belt layer composed of intersecting belt plies whose inclination directions are opposite to each other,
A pneumatic tire for a motorcycle including a tread portion disposed on the outer side in the tire radial direction of the crossing belt layer,
In the cross section in the tire width direction, when a tread surface distance between the tire equator surface and the tread edge is L, a first position of L / 3 along the tread surface from the tread edge to the tire equator surface side; A plurality of cords with an angle of 0 to 90 degrees with respect to the tire circumferential direction is embedded in the coated rubber between the tire equatorial plane and the second position of L / 6 along the tread surface from the tread end side. A pneumatic tire for a motorcycle, comprising at least one angled reinforcing member arranged.   3. The pneumatic tire for a motorcycle according to claim 1, wherein the angled reinforcing member includes two angled reinforcing members in which the cords intersect each other. 4.   The pneumatic tire for a motorcycle according to any one of claims 1 to 3, wherein L / 6≤W is satisfied when a width of the angled reinforcing member is W in a cross section in the tire width direction. A bead core embedded in a pair of left and right bead parts;
From at least one carcass ply in which a plurality of cords straddling from one bead portion to the other bead portion and having end portions wound around the bead core and locked to the bead core are embedded in the covering rubber Carcass
A belt layer composed of at least one belt ply in which a plurality of cords arranged on the outer side in the tire radial direction of the carcass are embedded in a covering rubber;
A tread portion disposed on the radially outer side of the belt layer, and a pneumatic tire for a motorcycle,
In the cross section in the tire width direction, when a tread surface distance between the tire equator surface and the tread edge is L, a first position of L / 3 along the tread surface from the tread edge to the tire equator surface side; The thickness is 0.5 to 4 mm so as to contact at least one of the belt layer and the carcass between the tire equatorial plane and the second position of L / 6 along the tread surface from the tread end side. The pneumatic rubber for motorcycles, comprising at least one reinforcing rubber member having a hardness equal to or higher than that of the higher-coating rubber of the carcass ply cord covering rubber and the belt ply cord covering rubber. tire.   6. The pneumatic tire for a motorcycle according to claim 5, wherein, in a cross section in the tire width direction, L / 6 ≦ W is satisfied when W is a width of the reinforcing rubber member.

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