JPS61122006A - Pneumatic tire for motorcycle with excellent high speed stability - Google Patents

Abstract

PURPOSE:To improve the high speed durability and high speed running stability of a motorcycle by arranging a reinforcing fabric layer made of organic fiber cords with a specific tilting angle between the upper and lower layers of a compound tread provided with the lower layer at a specific thickness in parallel to a carcass at a specific width. CONSTITUTION:A tread 1 consists of upper and lower rubber layers 4 and 5 having 1.5-3mm thicknesses. In addition, one or more reinforcing fabric layers 6 consisting of a cord layer in which organic fiber cords are arranged within the range of 5-25 deg. for the equator and having the 30-90% width of the width W of the tread 1 are arranged between the upper and lower lower layers 4 and 5 in parallel to the contour of a carcass 3. Besides, the width of the lower rubber layer 5 is at least equal to that of the reinforcing fabric layer 6 and the gage ratio h1 to h2 of the upper and lower layers 4 and 5 are set to approximately 0.25-0.60. As a result of this structure, the high speed durability of a motorcycle can be maintained and its high speed running stability after wear can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic tire for motorcycles that has excellent high-speed stability.

(Prior art) Conventional pneumatic tires for high-speed motorcycles have organic fiber cords with a diameter of 28 to
Reinforced with a so-called bias structure carcass consisting of two or more cord layers intersecting each other at a cord angle of 46,
A tread portion of rubber over the crown region of the carcass has a substantially uniform thickness over that region, such that the surface of the tread portion occupies a substantially parallel relationship along the contour of the carcass. Ru.

(Problem to be solved by the invention) On the other hand, as vehicles have become faster in recent years, there has been a growing demand for improved high-speed durability of motorcycle tires. Driving stability is becoming an increasingly important issue. As a countermeasure to this problem, attempts have been made to increase the size of the skid base gauge and lower the cord angle of the carcass in order to improve running stability after wear, but as a result, the problem of disadvantageous high-speed durability has arisen. occured.

Therefore, the present invention maintains the high-speed durability of the tire when new,
The purpose of the present invention is to provide a pneumatic tire for motorcycles that exhibits high-speed running stability after wear.

(Means for Solving the Problems) In order to ensure the running stability of a pneumatic tire for a high-speed motorcycle in a state of advanced wear, the present inventor has increased the degree of code A of the carcass and plaaker compared to the conventional one. It was found that the above objectives were achieved by increasing the thickness of the skid base rubber to maintain high speed, and by researching reinforcement within the tread layer and arranging a reinforcing fabric layer to have a hoop effect to maintain high speed. This is what I found.

That is, the pneumatic motorcycle tire of the present invention with excellent high-speed stability has a pair of sidewalls and a tread that spans both sidewalls, and each part is made of a plurality of organic fiber cord layers extending in a toroidal shape. The tire is reinforced with a carcass consisting of a cord layer having a cord angle of 32 to 42 degrees with respect to the equator and the cords intersecting each other between the layers, and the tread has a lower rubber layer having a thickness of 1.50 to 8 mm. and an upper rubber layer located above the composite body, the entire body extending parallel to the carcass contour to the maximum width position of the tire under substantially equal wall thickness, and organic fibers between the lower rubber layer and the upper rubber layer. At least one reinforcing fabric layer is arranged parallel to the carcass contour, which is composed of a cord layer in which cords are arranged at an angle of 5 to 25 with respect to the equator, and has a width corresponding to 80% to 90% of the tread width. , is characterized by the following.

Since the tire of the present invention is a motorcycle tire, in view of its maneuverability, the tread is extended parallel to the carcass contour to the maximum width position of the tire, and its thickness is substantially the same. Turning while a wheeled vehicle is running gives a so-called camber angle, that is, an angle between the plane of the tire that includes the equator and the vertical line, and is possible due to the camber thrust generated in the tire at that time, and when the camber angle is set, it becomes smooth. This is to obtain camber thrust.

In addition, the tread has a lower rubber layer of 1.5 II wing to 3 dragon thickness,
A groove is formed from a composite material including an upper rubber layer that is located on the upper part and is in contact with the road surface, and is embedded between the lower rubber layer and the upper rubber layer to exhibit a reinforcing effect combined with the carcass or the carcass and the plaaker. This requires the reinforcing fabric layer to be placed substantially parallel to the carcass contour. For the rubber of the upper rubber layer and the rubber of the lower rubber layer, from the viewpoint of emphasizing high-speed durability, the rubber of the lower rubber layer is used with less loss than the rubber of the upper rubber layer, in order to further improve high-speed durability. However, the upper rubber layer and the lower rubber layer may be formed of the same rubber material. The rubber used for the upper rubber layer has an E' of 50 to 120 kg//cm.
" % tan δ/E / is 0.008 to 0.006, and the rubber used for the lower rubber layer has an E' of 50 to 1.
20 vcl112, tanδ/Et is 0.0085
It is preferable to use one that is smaller than the upper rubber. The width of the lower rubber layer is at least equal to the width of the reinforcing 7 plastic layer. And the gauge h2 of the upper rubber layer and the lower part for the skid base gauge.

If the gauge of the rubber layer is h, h1/h2 is 0.25 to 0.
．． It is preferable to set it to 60.

Next, the cord in the cord layer of the carcass is made of nylon,
Made of organic fiber cord such as polyester,
The cord angle is 32-42 with respect to the equator. When the cord angle exceeds 42 degrees, there is a significant drop in high-speed durability, and when the cord angle is less than 32 degrees, the bending rigidity of that part becomes too high, which is not desirable in terms of running stability after wear.

In the tire of the present invention, a plurality of cord layers, usually four, are arranged so that the cords intersect with each other between the layers, but the number of cord layers is determined by the tire size and the cord. Set as appropriate depending on the thickness.

Next, the cords of the reinforcing fabric layer are made of organic fiber cords typically made of nylon, polyester, etc., like the carcass, and the cord angle is 6 to 26, preferably 5 to 15 with respect to the equator. If the cord angle is less than 5 degrees, there will be a decrease in riding comfort due to the hoop effect, that is, the ride will be rough, and if it exceeds 25 degrees, there will be no contribution to the hoop effect, which is undesirable. In the present invention, the reinforcing fabric layer is formed from at least one cord layer symmetrical with respect to the equator of the tire, and when using multiple cords, the layers are arranged in such a manner that the cords cross each other. The width is 4 of the tread width (W)
The width is 0 to 90%, more preferably 50 to 85%. If the arrangement width is less than 40 inches, the effect of suppressing the protrusion of the tread portion is small, and if it exceeds 90%, problems such as the cord protruding from a part of the shoulder are likely to occur.

Next, in the tire of the present invention, in order to further increase the composite reinforcing effect of the reinforcing fabric layer and the carcass, a cord made of the same material as the carcass is installed between the lower rubber layer of the tread and the carcass in parallel with the outline of the carcass. One or two plaakers having an arrangement angle of , with a width equal to or greater than the reinforcing fabric layer, can be used with the maximum width as the bead position.

(Example) Fig. 1 shows an example of a pneumatic tire for a motorcycle according to the present invention, but the illustration of internal reinforcement is omitted in the right half.

As shown in the figure, a tread 1 and a sidewall portion 2
is reinforced by a carcass 8 extending in a toroidal shape, and in this example, two layers, cord layers 8□ and 32, are used as the carcass. 8 is a bead core, and around it are both cord layers 8□, 8. Rewind each from the inside of the tire to the outside,
The cord layer 31 is arranged to extend higher into the sidewall rubber 2 beyond the end of the cord wound at 3 degrees. The tread rubber then has a substantially uniform thickness over its crown region along the contour of the carcass and extends over a flap W measured along its surface. As shown in the figure, the tread rubber is composed of a composite of a lower rubber layer 5 and an upper rubber layer 402 located above it, and a reinforcing layer 6 is disposed between these two layers. The fabric layer 6 is in this example 1 with a width W0 measured along the contour of the carcass.
It shall consist of layers.

In the illustrated tire, a play calf is further arranged surrounding the carcass 8, and this play calf extends along the contour of the carcass to the bead portion. As already mentioned, this play calf is not necessarily required in the tire of the present invention.

In the above cross-sectional structure, the carcass 3 has a bias structure in which the cord layers 3□, 3□, in which 1890 d/2 nylon cords are arranged at a cord angle of 38 with respect to the equator of the tire, intersect with each other, and the play calf is also attached to the carcass. The code is arranged so that the code N3 and the code intersect in the same code layer.

On the other hand, the reinforcing fabric layer 6 is made of nylon cord 12 a
o d/z is formed by a cord layer arranged at a cord angle of 15° with respect to the equator of the tire, the arrangement width W0 is 60% of the tread width W, and the thickness of the lower rubber JI is J-2, Off, reinforcement 7.
Thickness between the applicator and the tread groove bottom, -2,0II
I is placed between the upper rubber layer and the lower rubber layer. And as the rubber of the upper rubber layer, E' = 100 '9/cm
5tan δ/E'
-0,0028c7) Mo(7) Use t, ri.

In this way, a test tire with a size of 180/80-18 was made and used as the rear wheel of a two-wheeled vehicle.
High-speed durability and running stability (
(after wear) was evaluated.

On the other hand, for the carcass and player, set the cord angle to 3.
Comparative Tire 1, which is the same except that it is set to 0°, and has no reinforcing fabric layer; and Comparative Tire, in which the cord angle of the carcass and play car is set to 34 with emphasis on running stability after wear compared to Comparative Tire 1. A comparative tire 2 similar to 1 was manufactured as a trial. In this case, the tread rubber of Comparative Tires 1 and 2 was the same as the upper rubber layer used in the Example Tire. The test results obtained are shown in Table 1 below.

The high-speed durability in Table 1 is for the rear wheels (180/80-18 size), internal pressure 3, Okg/cm2, load a
170 kI on a smooth steel drum with a door diameter of 1.7 under the conditions of ooJc9! Start at I/h speed and run for 10 minutes without any abnormalities, then increase the speed by -1 in 10 krVh increments and do 1 g o k for each 10 minutes! I/h, then load 80 (19 at a speed of 200 kl/h for 20 minutes, load 285119 at a speed of 210 kl/h for 20 minutes, load 270 ~ at a speed of 220''/h for 20 minutes, The machine was run for 20 minutes at a speed of 2 +3 o kVh with a load of 255 kg, and for 20 minutes at a speed of 240 kl/h with a load of 240C9, and if it ran without any abnormality,
The speed was increased by 10 ICI/h and the vehicle was run for 20 minutes each, and the speed at which the failure occurred was evaluated.

In addition, the running stability is 2.25”η for both the internal pressure front axle and rear axle.
- 4.5 laps per lap on a two-wheeled vehicle with a load of 1 person and a displacement of 75 QCC.
Runs on an 8kra circuit, with a maximum speed of 210kI+3
The evaluation was based on the feeling at /h.

In addition, E', tan δ/E'C of the rubber of the lower rubber layer in the table
I! Using a viscoelastic spectrometer manufactured by Script Manufacturing Co., Ltd., a sample was taken with a length of 2 Qu, a width of 5 mm, and a thickness of 2 fl, and an initial strain of 5 cm, a vibration of 111 in 1%, and a frequency of 50 H.
z, temperature range Ffli-10~50℃) condition, temperature 8
Storage modulus E' and gastric standiene at 0°C) t
Evaluation was performed by measuring and δ.

(Effects of the Invention) As explained above, according to the present invention, there is a gap between the lower rubber layer and the upper rubber layer of the tread comb of 80 to 90 mm of the tread width.
By arranging at least one reinforcing fiber layer having a width corresponding to 0.0 inch, it is possible to significantly improve high-speed running stability after wear when mounted on a motorcycle and when running straight and turning.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a tire as an example of the present invention. 1...Tread 2...Side wall 8.
・・Carcass 3□, 8□・・Cord layer 4・・
・Upper rubber layer 5...Lower rubber layer 6...Reinforcement fabric layer 7...Player 8...Bead fabric Figure 1

Claims (1)

[Claims] 1. A pair of sidewalls and a tread spanning both of these sidewalls are connected, and each of these parts is reinforced with a carcass consisting of a plurality of organic fiber cord layers extending in a toroidal shape, and the cord layer is attached to the equator. The cord angle is 32
A tire in which the cords intersect with each other between layers at an angle of ~42°, the tread is composed of a composite body including a lower rubber layer having a thickness of 1.5 mm to 3 mm and an upper rubber layer located above the lower rubber layer, and the entire extends parallel to the carcass contour to the maximum width position of the tire under substantially equal wall thickness, and an organic fiber cord is arranged between the lower rubber layer and the upper rubber layer at an angle of 5° to the equator.
A high-speed vehicle characterized in that at least one reinforcing fabric layer consisting of cord layers arranged at an angle of ~25° and having a width corresponding to 30% to 90% of the tread width is arranged parallel to the carcass contour. A pneumatic tire for motorcycles with excellent stability. 2. A breaker consisting of one or two cord layers having the same cord type and cord arrangement angle as the carcass is provided in the lower part of the tread, between the rubber layer and the carcass and parallel to the carcass. Pneumatic tires listed in section.