JP3157940B2 - Motorcycle tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The running stability and durability in high-speed turning can be improved by maintaining the running stability in straight running in high-speed running and increasing the feeling of contact with the ground without lowering the sense of rigidity in turning. The present invention relates to a motorcycle tire.

[0002]

2. Description of the Related Art In a tire for a motorcycle, since the vehicle body runs with a large inclination when turning, it is necessary to maintain running stability even during this turning, and the tire has a large lateral rigidity. That is, tires having a cross-ply structure have been widely used. However, in recent years, as the expressway network has been enhanced and the performance of the vehicle body has been improved, the performance of motorcycle tires has been required to be improved for high-speed running.

[0003] In response to such a demand for high speed, tires having a radial structure have appeared even for motorcycles.
This radial tire for a motorcycle is, for example, a ply piece in which the entire belt layer is spirally wound with a narrow band ply adjacent to the outside of the carcass as proposed by the applicant in Japanese Patent Application No. 2-103305. Since it is formed, the bending rigidity in the radial direction is low, and thus the contact property is high, so that the running stability is improved. Also, the envelope characteristics are good, and the riding comfort is improved.

Furthermore, since the cord of the ply is continuous in the circumferential direction as compared with the conventional structure formed by joining cut plies, the belt layer has a high flap effect, and the outer diameter of the tire changes due to centrifugal force. Can be effectively prevented, and the traveling performance is improved when traveling straight ahead, particularly at high speed traveling.

[0005] However, the belt layer formed by the spiral winding of the belt-like ply, when turning while the vehicle body is inclined,
Since the belt layer is flexible, the lateral rigidity is poor, the camber thrust and the cornering force are both small, and a high side force required at the time of turning cannot be induced.

In order to supplement the lateral rigidity, Japanese Patent Laid-Open No.
In No. 5103, the applicant has proposed a method of increasing the tip height of the winding portion of the carcass, a method of increasing the tip height of the bead apex, and the like.

[0007]

However, although the lateral rigidity of the sidewall portion is increased by the above-mentioned proposal, both sides of the tire are too hard and the vertical spring constant is increased. In addition, the balance between the vertical spring constant and the horizontal spring constant is lost, so that the ground contact feeling is insufficient at the time of turning and the ride comfort is reduced,
There is a problem that the tire weight increases.

In addition, during high-speed running, the vehicle reacts sensitively to irregularities on the road surface, causing vibration of the vehicle body induced from the road surface, that is, a weave phenomenon, which is a factor that hinders speeding up.

As a result of conducting various investigations to solve the above problems, the inventor found that the vertical spring constant of the tire was highest in the range of 30 to 40 degrees at which the camber angle was maximized, and that the kimber angle was zero. It was found that it is more preferable that the longitudinal spring constant gradually increases as the degree becomes larger.

In order to satisfy the condition of the longitudinal spring constant, the height of the bead apex and the height of the winding portion of the carcass are restricted, and a filler made of a hard rubber composition is provided between the carcass and the belt layer. It has been confirmed by experiments that it is effective to provide the filler and regulate the arrangement position of the filler and the cross-sectional shape thereof.

According to the present invention, there is provided an automatic vehicle which can improve a high-speed turning performance and durability by increasing a sense of rigidity and a feeling of contact with a ground as the camber angle increases while maintaining running stability at a high speed straight traveling. It aims to provide motorcycle tires.

[0012]

The present invention has a main body extending from an arc-shaped tread portion through a sidewall portion to a bead portion, and a winding portion connected to the main body portion and turned around a bead core of the bead portion. A carcass using one or more carcass plies, a bead apex extending between a main body portion and a winding portion of the carcass and extending outward from a radial outer side of the bead core, and a radius of the carcass inside the tread portion. A radial tire for a motorcycle comprising a belt layer disposed on the outer side in a direction and a distance between both ends in the tire axial direction of a tread portion having a maximum width of the tire, wherein the bead apex has a JISA hardness of 50 to 50.
The upper end height Ha of the 56-degree rubber composition from the bead base line L is 0.3 to 0.55 of the tread edge height Hs which is the radial height between the bead base line L and the tread edge. And the upper end height Hd of the winding portion of the carcass ply is equal to the tread edge height Hs.
On the other hand, the surface length of the belt layer between the belt layer and the carcass and between the belt layer and the carcass and from the outer edge of the belt layer in the tire axial direction to the tire axial direction in the tire meridian cross section is 0. A filler made of a rubber composition having a JISA hardness of 50 to 80 degrees and having a thickness gradually decreasing inward is arranged in a range of 0.075 times or more and 0.2 times or less, and the outer edge of the belt layer is provided. The thickness t of the filler on a normal line N passing through the belt layer is 0.05 to 0.5 times the rubber thickness T from the tread surface on the normal line N to the outward surface of the carcass. Is characterized in that a belt cord made of organic fiber is covered with a topping rubber, and is formed of one or more ply pieces which are spirally wound at a slant at an angle substantially parallel to the tire equator with a narrow band-shaped ply being spirally wound. Motorcycle A tire.

[0013]

The belt layer is composed of ply pieces formed by spirally winding a belt-like ply in which a belt cord is embedded in topping rubber, so that the tread is smaller than that of a conventional cross belt formed using a cut ply. In addition to reducing the rigidity facing inward in the radial direction of the part, increasing the contactability and gripping, there is no seam inclined to the equator of the tire like a conventional belt layer where cut plies are joined, and it goes straight and turns Steering stability at the time can be improved.

Also, the height Hd of the upper end of the winding portion of the carcass ply
And the upper end height Ha of the bead apex are both restricted to the range of 0.3 to 0.55 times the tread edge height Hs, so that the rigidity of the tire side is reduced and the camber angle is small when traveling straight. Ride comfort is improved. When the upper end height of the bead apex and the winding portion of the carcass ply is less than 0.3 times the tread edge height, the lateral rigidity of the upper portion of the bead portion is low, and the convergence due to disturbance is deteriorated and at the time of going straight. Driving stability decreases. On the other hand, when each of the upper end heights exceeds 0.55 times the tread edge height,
When the rigidity of the tire side portion is too high, the riding comfort when traveling straight ahead with a small camber angle is reduced.

The bead apex has a hardness of 50 to 50.
By setting the angle at 56 degrees, the rigidity of the bead portion is adjusted in conjunction with the regulation of the upper end height of the bead apex, and it is possible to control the ride comfort and the steering stability when traveling straight, respectively. If the hardness is less than 50 degrees, the stiffness of the bead portion is reduced, the convergence to disturbance is reduced, and the steering stability is poor. On the other hand, if the angle exceeds 57 degrees, the rigidity of the bead portion becomes too high, and the riding comfort when traveling straight ahead decreases.

Further, a distance between the belt layer and the carcass and inward in the tire axial direction from the outer edge of the belt layer to a distance of not less than 0.075 times and not more than 0.2 times the surface length of the belt layer, A filler made of a rubber composition having a restricted rubber hardness and thickness is provided. By providing such a filler, the vertical spring constant of the tire has a tendency to gradually increase as the camber angle increases, and when the camber angle runs at a maximum inclination angle of 30 to 40 degrees, the maximum camber thrust is reduced. Can be generated. As a result, a feeling of contact with the ground can be increased while maintaining a sense of rigidity, and running stability during turning can be improved.

Here, the vertical spring constant is defined as a value obtained by applying a load to the tire and bending the tire in a state where a predetermined internal pressure is applied to the tire cavity while the tire is mounted on the rim, and the load and the lateral And the correlation with the vertical deflection is obtained, and the deflection curve is expressed by the slope of the tangent at the actual load used.

The range between the belt layer of the filler and the carcass is 0.075 of the surface length of the belt layer.
If the camber angle increases or decreases, the vertical spring constant fluctuates greatly.If the range exceeds 0.2 times, the tread portion has a poor tactile sensation. As a result of the increase in tread rigidity even in the central region, when the vehicle is running straight, the contact stability is poor, and the running stability and riding comfort are reduced.

If the rubber hardness of the filler is less than 50 degrees according to JIS, the tread shoulder region is inferior in rigidity. As a result, the feeling of rigidity in turning is reduced, the running stability in turning is reduced, and the durability is inferior. On the other hand, when the angle exceeds 80 degrees, the workability of processing the rubber composition is deteriorated, and the rigidity of the tread shoulder region becomes excessively large, and the running stability in straight running and turning running is reduced.

Further, the filler has a thickness t on the normal line N passing through the outer edge of the belt layer, which is 0.0% of the rubber thickness T on the normal line N.
5 to 0.5 times. When the thickness t of the filler is less than 0.05 times the rubber thickness T, the thickness of the rubber of the filler is reduced and the feeling of contact with the ground is inferior. On the other hand, when the thickness exceeds 0.5 times, the rigidity in the tread shoulder region becomes excessive and the ride comfort is increased. Is reduced.

Further, the thickness of the filler is gradually reduced inward, so that the rigidity step of the tread portion can be reduced and the running stability during turning can be further improved.

As described above, the motorcycle tire according to the present invention can increase the camber angle without deteriorating the ride comfort when traveling straight by combining the above-mentioned components organically and integrally. This enhances the feeling of ground contact when traveling and improves traveling stability when turning.

[0023]

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 to 3, the motorcycle tire 1 has a tread width TW, which is a distance in the tire axial direction between the edges E of the tread portion 2, and a maximum width of the tire, and a tread surface 2A.
Is formed as a tire for a motorcycle having an arc shape centered on the tire equator C, and includes a tread portion 2, sidewall portions 3, 3 extending radially inward from both ends thereof, and the sidewall portion. 3 and a pair of bead portions 4 and 4 located at radially inner ends of the tire. Further, the motorcycle tire 1 has a winding portion which turns a bead core 5 of the bead portion 4 from the inside in the tire axial direction to the outside thereof on a main body portion 6a extending from the tread portion 2 through the sidewall portion 3 to the bead portion 4. 6b, and a belt layer 7 disposed inside the tread portion 2 and radially outside the carcass 6. A filler 9 is provided between the carcass 6 and the belt layer 7 of the tread portion 2 and near the outer edge F of the belt layer 7.

In the present embodiment, a bead apex 15 made of hard rubber and having a triangular cross section is set up outside the bead core 5 in the tire radial direction and between the main body 6a and the turn-back portion 6b of the carcass 6.

In the present embodiment, the carcass 6 comprises at least one carcass ply having a radially arranged carcass cord inclined at an angle of 70 to 90 degrees with respect to the tire equator C, and in this embodiment, one carcass ply. As the carcass cord, an organic fiber cord having an elastic modulus of preferably 600 kgf / mm ² or more, such as nylon, polyester, or aromatic polyamide fiber, is used. In this embodiment, the carcass 6 has a winding height Hd, which is the height from the bead base line 4a at the upper end of the winding portion 6b, and is the distance from the bead base line 4a of the edge E of the tread portion 2. The height is set in the range of 0.3 to 0.55 times the tread edge height Hs. Here, the bead base line 4a is a line parallel to the tire axis passing through the outer end in the tire axial direction of the bottom surface of the beat.

The bead apex 15 is made of a rubber composition having a JISA hardness of 50 to 56 degrees, and the upper end height Ha, which is the height of the upper end from the bead base line 4a, is 0.3 of the tread edge height Hs. The range is 0.55 times.

In the embodiment, the belt layer 7 has a surface length BS between the outer edges of the belt layer in the meridian section of the tire which is equal to the surface length L between the tread edges E along the tread surface 2A.
The range is set to be 8 times or more and 0.9 times or less.

The belt layer 7 is a narrow and long belt-like ply 1.
A ply piece 8 formed by spirally winding 0 is formed. As shown in FIG. 2, the belt ply 10 has one or a plurality of belt cords 11 arranged in parallel, and in this embodiment, two belt cords 11, 11 are embedded in a topping rubber 12, and the belt cord 11 is made of nylon, In addition to organic fiber cords such as polyester and aromatic polyamide, steel cords are used. As the belt cord 11, the aromatic polyamide fiber having substantially the same tensile strength and elastic modulus as steel and having a smaller weight than steel can be suitably used.

The belt-like ply 10 is moved from left to right in FIG. 1 and from the tire equator C from the starting point H1 which is the outer edge F of the belt layer 7 located near one edge E of the tread portion 2.
The ply piece 8 can be formed by spirally winding the tire at a small angle of 5 ° or less with respect to the tire equator C until reaching the end point H2 which is the outer edge F of the belt layer 7 near the other edge E. . Further, in this embodiment, as shown in FIG. 3, when winding the band-shaped ply 10, the vicinity of the opposing side edges 10 a, 10 a of the band-shaped ply 10 is wrapped around each other and wound.
The slack of the band-like ply 10 is prevented. The belt layer 7
Can be formed as two or more ply pieces 8 according to the above-described configuration, that is, a spiral winding of the belt-like ply 10 as a plurality of two or more layers.

When the cords of the carcass 6 are arranged radially as in this embodiment, the belt layer 7
The belt cord cooperates with the cord of the carcass 6 to exert a tag effect.

One end of the filler 9 is formed in the tire meridian section between the belt layer 7 and the carcass 6 and from the outer edge in the tire axial direction toward the tire axial direction, that is, toward the tire equator C. 0.0 of surface length BS
It extends over a range of a distance S of 75 times or more and 0.2 times or less, and the thickness gradually decreases inward, while the other end has a radius along the outer surface of the carcass 6 main body 6 a in the sidewall portion 3. Inward in the direction of the tread edge height Hs.
Extending at a length of 3 to 0.5 times and having a gap G of at least 5 mm between the tip of the bead apex 15 and
Moreover, the thickness is gradually reduced toward the inside in the radial direction.

The thickness of the filler 9 on the normal line N passing through the outer edge F of the belt layer 7 is set to the rubber thickness T from the tread surface 2A on the normal line N to the outward surface of the carcass 6. Is set to 0.05 to 0.5 times. The filler 9 has a rubber hardness of 50-80 degrees of JISA hardness, and has a lower rubber hardness than the tread rubber 16 forming the surface 2A of the tread portion 2 and the sidewall rubber 17 forming the side wall surface of the sidewall portion 3. Has a high hardness.

[0033]

[Example 1] A preliminary experiment was conducted to confirm the effect of the filler on the improvement of the feeling of contact with the ground and the feeling of rigidity.

For a tire having a size of 190 / 50R17, a prototype was produced according to the specifications shown in Table 1 (specifications A, B, and C), and a spring constant was measured in a camber angle range of 0 to 40 °. Equipped on a real vehicle, the effect of the filler was confirmed by running the vehicle. The spring constant is
The load was set in two stages (100 kg and 200 kg), and the feeling of contact with the ground and the feeling of rigidity were judged by the driver's feeling. The test results are shown in Table 1.

[0035]

[Table 1]

As a result of the test, it was confirmed that the specification C having the filler had good grounding feeling and good rigidity.

[0037]

[Specific Example 2] Based on the result of the preliminary test according to the specific example 1, the tire size is the same as that of the specific example 190 / 50R1.
A tire having the configuration shown in FIG. 1 and having the configuration shown in FIG. 1 was prototyped according to the specifications shown in Table 2 (Examples 1 and 2), and its performance was tested. For comparison, a test was also performed on a tire having a conventional configuration without a filler (Comparative Examples 1 and 2) and a tire Comparative Example 3-6 outside the configuration of the present invention, and the performances were compared.

The test conditions are as follows. 1) High-speed straight-running stability and high-speed turning stability The prototype tire was mounted on a motorcycle, the automobile was run at 260 km / Hr on a test road, respectively, and evaluated by the feeling of a test driver. It was indicated by an index. The higher the value, the better.

2) High-speed endurance test A prototype tire set with a tire internal pressure of 3.00 kgf / mm ² and a load of 355 kg was started at an initial speed of 250 km / Hr.
A high-speed endurance test was performed using a step speed method in which the speed increased by 10 km / Hr every 0 minutes, and the running distance was determined until cracks occurred in the tread portion and the bead portion. In Table 1, the results are shown as indices with the comparative example as 100. The higher the value, the better.

3) Camber thrust Using a maneuverability tester, the tire internal pressure was 3.00 kgf / mm ² ,
The load was set to 355 kg and the camber angles were measured at 10 ° and 40 °, respectively. The higher the value, the better. Table 2 shows the test results.

[0041]

[Table 2]

[0042]

As described above, the motorcycle tire of the present invention is characterized by providing a filler made of hard rubber having a regulated length range and thickness between a belt layer and a carcass. In addition, while maintaining the straight running stability at the time of high-speed running, it is possible to increase the feeling of contact with the ground without lowering the sense of rigidity at the time of turning, and it is possible to enhance the turning traveling performance and improve the durability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a belt-like ply.

FIG. 3 is a cross-sectional view illustrating the winding of a belt-like ply.

[Explanation of symbols]

 2 Tread part 3 Side wall part 4 Bead part 4a Bead base line 5 Bead core 6 Carcass 6a Body part 6b Winding part 7 Belt layer 9 Filler 10 Belt ply 11 Belt cord 12 Topping rubber 15 Bead apex BS Belt surface length C tire Equator F Outer edge Ha Upper edge height of bead apex Hb Upper edge height of winding portion of carcass ply Hs Tread edge height N Normal line S Range T Rubber thickness t Filler thickness

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60C 9/18-9/22 B60C 9/08

Claims (1)

(57) [Claims] 1. A carcass ply having at least one carcass ply having a main body extending from an arc-shaped tread portion through a sidewall portion to a bead portion and a winding portion connected to the main body portion and turned around a bead core of the bead portion. The carcass used, the bead apex extending outward from the radial outer edge of the bead core between the main body and the winding portion of the carcass, and a belt layer disposed inside the tread portion and radially outside the carcass. And a radial tire for a motorcycle having a maximum width of a tire with a distance between both ends in a tire axial direction of a tread portion, wherein the bead apex has a JISA hardness of 50 to 56 degree rubber composition. The upper end height Ha from the bead base line L is a tread edge height which is a radial height between the bead base line L and the tread edge. s of 0.3 to 0.55 times, and the upper end height Hd of the winding portion of the carcass ply is 0.3 to 0.55 times the tread edge height Hs, while the belt layer and the Between the carcass and from the outer edge of the belt layer in the tire axial direction to the inner side in the tire axial direction at a distance of not less than 0.075 times and not more than 0.2 times the surface length of the belt layer in the tire meridian section. A filler made of a rubber composition having a JISA hardness of 50 to 80 degrees, the thickness of which gradually decreases toward the surface, is arranged, and the thickness t of the filler on a normal line N passing through the outer edge of the belt layer is set to the normal line. N is 0.05 to 0.5 times the rubber thickness T from the tread surface on the N to the outward surface of the carcass, and the belt layer has a small width and length in which a belt cord made of an organic fiber is covered with topping rubber. Tie a long strip of ply Tire for a motorcycle, characterized in that formed by substantially parallel angle inclined one or more ply piece was wound helically with respect to the equator.