JPH0411502A - Motorcycle tire - Google Patents

Abstract

PURPOSE:To improve strength, productivity and air sealing property and realize lighter weight by providing liner layers on the inside and outside of a carcass in a mainframe portion ranging from a tread portion to a bead portion and using rubber composition containing a specified rate of butyl rubber halide as original rubber for each of the liner layers. CONSTITUTION:An inside liner layer 12 and an outside line layer 13 are provided on the inside of a mainframe portion 9A and on the outside of a turning portion 9B, at least ranging from a bead portion 4 to a sidewall portion 3, respectively, to eliminate conventional sidewall rubber. For each of the inside and outside liner layers 12, 13, rubber composition containing 60-100pts.wt. or less butyl rubber halide is used as original rubber. In this way, productivity, strength and air sealing property can be improved and lighter weight can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motorcycle tire that can increase productivity, improve air sealability, and achieve weight reduction.

[Conventional technology]

Conventionally, as shown in Figure 4, motorcycle tires have conventionally used two carcass plies b and b, which are usually folded on both sides around bead cores a and a, and each carcass cord is attached between the plies. The carcass has a frost bridle structure arranged in directions that intersect with each other, and a breaker C is painted on the outside of the crown of the carcass, and the outer circumferential surface is made of, for example, styrene-butadiene rubber (SB
It is covered with relatively hard trend rubber d and sidewall rubber e, which are mainly composed of diene rubber such as R) and are purchased in high quantities. The reason why such a loss ply structure is used is that this structure has excellent tire lateral rigidity due to the above-mentioned cord arrangement that intersects with each other, and this results in high cornering power that can counter centrifugal force during cornering. This makes it possible to right the vehicle body that is tilted at a high bank angle and to perform stable cornering.

[Problem to be solved by the invention]

However, in recent years, in addition to improving productivity, there has been a strong desire for such tires to have high structural strength, air sealability, and lightweight tires.

Therefore, for example, as shown in FIG. 4 (bl), a structure can be devised in which one carcass ply b1 is used and its folded parts are extended to overlap each other within the trend.

This product can form a cross-brid structure with one carcass ply b1, and the father-shaped portion f can function as a no-force force, making it possible to reduce the carcass forming process by half and the breaker forming process. . Furthermore, it is possible to suppress loosening of the carcass case and stress concentration at the folded end due to the conventional carcass folded part being interrupted at the sidewall part, thereby significantly contributing to improved productivity and structural strength.

However, there has been a growing demand for improved sealing performance and reduced tire weight in recent years, and the inventors therefore conducted further research into these problems.

As a result, with the structure devised above, the case is locked without loosening, so the tire's lateral rigidity is greater, and stress concentration at the folded end does not act on the sidewall. While maintaining the durability and running performance, it was possible to replace the sidewall rubber e with a relatively soft rubber with a low mass.

That is, the present invention adopts the devised carcass structure,
A motorcycle tire that is based on the provision of an outer liner layer in place of sidewall rubber in the sidewall part, which increases productivity, improves structural strength, and achieves weight reduction, and also helps improve air sealing performance. The purpose is to provide

[Means to solve the problem]

In order to solve the above-mentioned problems, the motorcycle tire of the present invention includes a main body part that surrounds the inner cavity of the tire by extending from the tread part through the sidewall part and reaching the bead core of the bead part; at least one carcass ply having a folded part that is folded back around the bead core from the inside facing the inner cavity of the tire to the outside and extends along the outer surface of the main body part and overlaps each other inside the trend part to form an overlapping part; an inner liner layer is provided on the inner surface of the main body portion, and an outer liner layer is provided on the outer surface of the folded portion extending from at least the bead portion to the sidewall portion;
The outer liner layer is formed from a rubber composition containing at least 60 to 100 parts by weight of halogenated butyl rubber as a raw material rubber.

[Effect]

In the motorcycle tire of the present invention configured as described above, the folded portion of the carcass ply folded around the bead core is extended along the outer surface of the main body portion, and forms an overlapping portion that overlaps each other within the tread. There is.

Therefore, for example, a single carcass ply can be used to form a loss bridle structure with high lateral rigidity, and the shaped portion can be used as a conventional breaker to create an I! can be made to function,
Trend rigidity can be improved and the main body can be protected. As a result, it is possible to reduce the carcass forming process by half and the breaker forming process while maintaining running performance, and productivity can be greatly improved.

On the other hand, since the folded portion is small (in both cases, an outer liner layer mainly composed of butyl halide, which has high airtightness and low mass, is provided on the outer surface extending from the bead portion to the sidewall portion), the tire While reducing the weight of the main body, air sealing performance can be greatly improved together with the inner liner layer inside the main body.

The use of an outer liner layer instead of the conventional sidewall rubber allows for a strong locking of the carcass case without loosening around the bead core, which is caused by the ends of the carcass plies overlapping at the trend part, and for securing the sidewall part. This can be achieved by eliminating stress concentrations at.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

In the figure, a motorcycle tire 1 has a trailing throat portion 2.
and a sidewall portion 3 extending inward in the tire radial direction from both sides thereof, and a bead portion 4 located at the radially inner end thereof.
It has a toroidal shape with a hollow tire cavity 5 formed inside.

Further, a carcass 7 is placed between the bead portions 4 and 4.

The tread portion 2 extends over the crown of the carcass 7 in an arcuate manner from the center of the crown toward both ends approximately parallel to its outline, and has a cross-sectional shape in which the straight line extends beyond the maximum center of the sidewall portion 4. This maintains the canoe thrust when the tire slopes.

The carcass 7 is made of at least one carcass ply 9, in this example, one carcass cord made of organic fibers such as nylon, rayon, polyester, etc., arranged at an angle of 35 to 70 degrees with respect to the tire equator. It is formed.

Further, the carcass ply 9 extends from the tread portion 2 through the sidewall portion 3 to the bead core 6 of the bead portion 4 to form a main body portion 9A that surrounds the tire inner cavity 5, and continues to the main body portion 9A and extends from the bead core 6. a pair of folded parts 9B which are folded back and locked from the inside facing the tire inner cavity 5 to the outside, and the folded parts 9B are fixed to the main body part 9A.
The folds 119b extending along the outer surface of the tread portion 2 form an overlapping portion 10 that overlaps each other inside the tread portion 2.

Therefore, the folded parts 9B and 9B cooperate with each other to
The carcass cords are superimposed over the entire outer surface of the main body portion 9A, and the carcass cords are turned in different directions by the folding and intersect with the carcass cords of the main body portion 9A, thereby forming a cross-bly structure having high rigidity. Further, due to the formation of the shaped portion 10, the carcass 7 forms three layers in the tread portion 2, and therefore, the overlapping portion 10 can function as a breaker that cushions the impact from the road surface, protects the carcass 7, and increases tread rigidity. .

Note that the overlapping portion 10 is f! In order to properly join the carcass 7 and lock the carcass 7 around the bead core 6 without loosening, it is necessary that the overlap width W be at least 0.2 times the tread width. In order for 10 to function as a breaker, it is preferable that the width be 0.3 times or more the tread width.

In the present invention, an inner liner layer 12 is further provided on the inner surface of the main body portion 9A, and an outer liner layer 13 is provided on the outer surface of the folded portion 9B extending from at least the bead portion 4 to the sidewall portion 3. The structure does not include the conventional sidewall rubber. Therefore, it is possible to achieve the same air sealing properties as well as to reduce the weight of the tire.

The inner liner layer 12 and the outer liner layer 13 are each made of halogenated butyl rubber alone or mixed with a diene rubber such as natural rubber, synthetic isoprene rubber, butadiene rubber, or styrene-butadiene rubber, which is low in weight and airtight. The inner liner layer 12 covers the entire inner surface of the main body 9 facing the tire inner cavity 5, and the outer liner layer 13 covers the outer surface of the folded portion 9B. For example, 1. OW or more and 2゜0
(2) It has a thickness t below and is attached approximately evenly.

Here, halogenated butyl rubber refers to chlorobutyl rubber,
It refers to a single halogenated rubber such as bromobutyl rubber or a mixture thereof, and the rubber composition contains 60 or more and 100 parts by weight or less of the halogenated butyl rubber as a raw material rubber, thereby exhibiting high airtightness.

In addition, if the content of the butyl halide is less than 60 parts by weight, and if the thickness is less than t months or 0w, the airtightness will be poor, and if the thickness t exceeds 2.0, the weight of the tire will be reduced and the cost will be reduced. inhibit the development of

In terms of productivity, it is preferable that the outer liner layer 13 be made of the same rubber composition and processed in the same process as the inner liner layer 12, but within the above-mentioned regulated range of the content of halogenated butyl rubber. For example, clay may be mixed with carbon black to increase the rubber strength.

In this way, the outer liner layer 13, like the inner liner layer 12, has high airtightness due to its main component being halogenated butyl rubber, improving the air sealing properties of the tire, while reducing the thickness t to make the tire lighter. can be achieved.

In addition, such a rubber composition also exhibits excellent weather resistance against ozone, heat, etc., and is therefore useful for improving tire durability over time.

Note that the adoption of such an outer liner layer 13 in place of the conventional sidewall rubber means that the folded end 9 of the carcass ply 9
By overlapping within the trend, the rigidity of the carcass case is strengthened and the load on the rubber is reduced in the sidewall part 3. This is achieved by reducing local stress concentration and associated tire damage.

Further, one end 13a of the outer liner layer 13 extends to the bead bottom and is connected to the inner liner layer 12, and the other end 13b is different from the trend rubber 15 forming the trend part 2. The length 11 along the above-described folded portion 9B is overlapped to suppress separation from the tread rubber 15.

Note that a reinforcing chafer (not shown) is provided in the bead portion 4 in the same manner as in conventional tires to prevent the rim from shifting.

Further, the outer liner layer 13 may be, for example, as shown in FIG.
The other end 13b can extend into the molded part 10, and in this case, the other end 13b has a length of 30 m or more from the fold m9b of the folded part 9B on the side to which the extranuclear liner layer 13 is attached. It is desirable to terminate the process before t2.

Incidentally, such a motorcycle tire 1 of the present invention has a third
It is formed using a conventional mold, as schematically shown in Figures (al~). That is, on the former F, the inner and outer liners 12
．． A carcass ply 9 is laid through a liner rubber 1G for forming the carcass ply 13, and a pair of bead cores 6.6 are separately purchased at a distance on the upper surface of the carcass ply 9.

Also, attach the carcass ply 9 on the outside of the bead core 6 to the liner rubber 1.
The tread rubber 15 is disposed on the template portion 10, and is then shaved into a toroidal shape using high pressure air flowing in from the former F to form a low cover. After forming, mold vulcanization is performed.

〔Concrete example〕

It has the structure shown in Figures 1 and 2 and has a tire size of 3.
A prototype tire of OO-8 was produced based on the specifications shown in Table 1, and the air sealing properties of the prototype tire were evaluated. The weight, maneuverability, stability and durability were measured respectively.

The rubber compound used for the inner and outer liner layers is Show the table.

The measurement method is as follows.

Durability performance test: Conforms to JATMA Safety Standards-1984 4-3 (7). The distance traveled before the damage occurred is compared. The mileage of the conventional product is expressed as an index with the mileage as 100, and the larger the index, the better the product.

1A 1! ! ! .

No. 2 7I ta+ Table 2 (bl Air seal performance test: Filling the weir with an internal pressure of 10 kgf/am'', 1lt142.5
After leaving it in a constant temperature room for 30 days, the amount of decrease in internal pressure was measured. It is expressed as an index, with the amount of reduction of the conventional product set as 100, and the smaller the index, the better.

Maneuverability test: Each test tire was mounted on a normal maneuverability tester indoors, the cornering power was measured under a load of 95 kg, and the performance of the conventional product was subtracted by 100 and displayed as an index. The larger the index, the better. show.

Driving stability performance test: i!
I-adjustment stability, turning stability, grip, etc. are evaluated by feeling, and the conventional product is set as 100, and the index is shown, and the larger the index, the better ζ.

〔Effect of the invention〕

As mentioned above, the two-wheeled vehicle tire of the present invention has one carcass ply folded (71 parts) and four treads that are folded together inside the tread, and halogen is applied to the inside of the main body of the carcass ply on both sides and the outer surface of the folded part, respectively. The main component of the liner is fluorinated butyl rubber, and the liner is used as a first class liner, which greatly improves tire productivity.Moreover, while maintaining running performance and durability, it improves air sealing performance and improves the tire's light weight. can be achieved to a large extent.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the present invention, and FIGS.
4 is a schematic diagram explaining the formation method, and FIG.
3.-side wall part, 4-bead part, 6
- bead core, 7 - carcass, 9 - carcass ply, 9A - body part, 9B - folded part, 10 - overlapping part, 12 - liner layer inside, 1
3-・Outer liner layer. Patent Applicant: Sumitomo Rubber Industries Co., Ltd. Agent: Mr. Nae Tadashi 2nd rI! J Figure 3 (a) Figure 4 (b) Figure 114 (a)

Claims (1)

[Claims] 1 A main body part that extends from the tread part through the sidewall part to the bead core of the bead part to surround the inner cavity of the tire, and a main part that continues to the main body part and is folded around the bead core from the inside facing the tire inner cavity to the outside. and a carcass formed of at least one carcass ply, which extends along the outer surface of the main body and has a folded portion that overlaps with each other inside the tread, and has an inner ply on the inner surface of the main body. An outer liner layer is provided on the outer surface of the folded portion extending from at least the bead portion to the sidewall portion, and the inner and outer liner layers contain at least 60 and 100 parts by weight of halogenated butyl rubber as a raw material rubber. A motorcycle tire formed from a rubber composition containing the following.