JPS5893605A - Radial tire - Google Patents

Abstract

PURPOSE:To reduce the weight of a tire without loss of the side cut resistance characteristics and the productivity of the tire by inserting the end of a reinforced carcass ply provided at the outside of the tire. CONSTITUTION:A two ply carcass radial tire E is composed by folding up the only carcass ply 1 located at the inside of the tire around a bead wire 6, and inserting the end part 10 of a reinforced carcass ply 9 located at the outside of the tire between the folded up part 1' of the carcass ply 1 and the carcass ply 1 located at the inside of the tire. The adequate hight (h) of the folded up part 1' of the carcass ply 1 located at the inside of the folded up tire around the bead wire 6 is less than 30% of the internal perimeter length L in the radial section.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial tire, and more particularly to a radial tire having an improved carcass structure in order to reduce the tire weight without impairing side cut resistance or productivity.

The carcass structure of a conventional two-bright carcass radial tire for passenger cars is a 2-0 ply lock structure, as shown in FIG. 1, that is, the carcass structure is located on the inner side of the tire. ``A structure in which the knee seventh sply 1 and the carcass ply 2 located on the outside of the tire are both rolled up so as to wrap around the bead wire 6 is the mainstream.This 2-0 ply lock structure is used in the tire manufacturing process when the 2-ply carcass ply is rolled up to wrap around the bead wire 6. 1
and 2 can be wound around the bead wire 6 at the same time, productivity is good, and side cut resistance is also good. However, in this type of tire, if the winding width of each carcass ply is reduced by 1, it not only becomes difficult to wind the carcass ply, but also the cut end of the carcass is likely to be placed directly under the ped wire, making the tire uniformity unstable. There is a problem in that it is necessary to widen the winding width of each carcass ply, which makes it difficult to reduce the weight of the tire.

However, this increase or decrease in tire weight has a direct impact on vehicle fuel efficiency and ride comfort, so reducing this is currently an important issue.

Recently, as shown in Fig. 2, only the carcass ply 1 located on the inside of the tire is wound up so as to wrap around the bead wire 6, and the carcass ply 2 located on the outside of the tire is
Do not wind up the pea wire 6 from the outside of the pea filler 8.
A carcass structure has been proposed, which is a so-called 1-1 ply lock structure in which the locks are arranged close to each other.

This carcass structure with a 1-1 ply lock is structured so that only one layer of carcass plies located on the inside of the tire is wound around the bead wire as described above, and the other carcass plies end near the bead wire. The carcass width can be reduced by the winding width of 1 ply,
The weight of the tire can be reduced by this amount.

However, with this 1-1 ply lock carcass structure, in the tire manufacturing process, it is necessary to first wind up one carcass ply around the ped wire, and then arrange the other carcass plies as described above.
Compared to the 2-0 ply lock structure that can be formed in a single winding process as mentioned above, productivity is not only about 10% lower, but the side cut resistance is significantly higher than that of the 2-0 ply lock structure tire. There is a problem that it is inferior.

An object of the present invention is to provide a radial tire with a carcass structure configured to eliminate the above-mentioned problems and reduce the tire weight without impairing the tire's side cut resistance and productivity. be.

The feature is that in a 2-ply carcass radial tire, only the carcass ply located on the inner side of the tire is wound around the bead wire.
By inserting the end of the reinforced carcass ply located on the outside of the tire between this winding part and the carcass ply located on the inside of the tie y, the side cut resistance is as high as that of the radial tire with the aforementioned 2-0 ply lock structure. It is possible to reduce tire weight while maintaining performance and productivity.

Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

FIG. 3 is an explanatory sectional view of a main part of a radial tire according to an embodiment of the present invention.

In the figure, E is a radial tire made of an embodiment of the present invention, and in a 2-ply carcass radial tire,
Only the carcass ply 1 located on the inside of the tire is wound up around the bead wire 6, and between this rolled up portion 1' and the carcass ply 1 located on the inside of the tire, an end portion 10 of the reinforcing carcass ply 9 located on the outside of the tire is placed. It is constructed by inserting the .

What is the 2-ply carcass radial tire mentioned above?
The so-called carcass angle is not limited to an angle of approximately 90° with respect to the tire circumferential direction, but is an angle of 70° to 85°. Including semi-radical tires.

The material of the carcass may be any commonly used tire cord such as evanylon, polyester, or rayon.

In addition, a pair of bead wires, a pair of sidewalls, and adjacent thereto, there is a 10° to 3°
It has a tread portion on which multiple belt reinforcing layers made of steel, rayon, etc. are arranged at an angle of 0°.

To further explain this structure, as mentioned above, the height h of the rolled-up portion 1' of the carcass ply 10 located inside the tire wound around the bead wire 6 is less than 30% of the inner peripheral length of the tire in the radial direction. It is better to do so. This is because if the height h of the winding portion 1' exceeds 30% of the inner circumference length, the width of the carcass ply 1 becomes wider than necessary.
This is because the weight of the carcass ply 1 increases by this amount, which is undesirable because it goes against the reduction in tire weight, which is one of the objectives of the present invention, and leads to increased costs, deterioration of fuel efficiency, and ride comfort.

Further, as described above, the present invention provides a carcass ply 1 located inside the tire. The reinforcing carcass is constructed by inserting the end 10 of the reinforcing carcass ply 9 located on the outside of the tire between the winding portion 1' and the winding portion 1', and the reinforcing carcass is installed on the outside of the tire as in the case of the conventional 2-0 ply lock. Since the ply 9 is not wound around the bead wire 6, the width of the reinforcing carcass ply 9 located on the outside of the tire can be narrowed, reducing the carcass weight by 5 to 15% compared to the conventional 2-0 ply lock. Moreover, since the carcass ply winding process only needs to be carried out once in the molding process, the molding productivity is as good as that of the 2-0 ply lock described above.

Furthermore, in the present invention, as described above, the reinforcing carcass ply 9 located on the outside of the tire is not rolled up, so that it is possible to prevent defective unibody form and vulcanization failure around the bead caused by narrowing the width of rolling up.

In this embodiment, the end 10a of the end 10 of the reinforcing carcass ply 9, which is inserted between the carcass ply 1 located inside the tire and its rolled-up portion 1', is interposed between the peed wire 6 and the end 10a of the reinforcing carcass ply 9.

The interval N is set by the device, and this interval N is N25.
It's stupid to set it as %. This means that if the distance N is less than 51X, the terminals 10a75. of the reinforcing carcass 9. This is because there is a possibility that it overlaps with the peed wire 6 in the E-forming process and makes the uniformity unstable.

In addition, the width L9 of the reinforcing carcass 9 described above is at least 50% of the tire's radial cross-sectional inner circumferential length, and is equally spaced on the left and right with the center of the tire cross-section as the center. The sidewall part of the tire which is prone to cause damage is covered with two layers, the carcass ply 1 located inside the tire and the reinforced carcass ply 9, so that side cut resistance can be maintained. Note that if the width L9 of the reinforcing carcass 9 is less than 50% of the circumferential length, the position of the end 1Oa of the reinforcing carcass 9 moves toward the tread. 1, the end 1m of the red side end 1m and the end 10a of the reinforcing carcass 9 are located in the flex zone (the zone most often subjected to bending deformation during driving) in the sidewall part of the tire. This is not preferable because the durability of the material deteriorates.

Further, as described above, the end portion 10 of the tough carcass ply 9 is wedged between the carcass ply 1 and its rolled-up portion 1', and in this scissored portion, the coating rubber layer of each ply is removed. Assuming that the substantial adhesion length m of the part where the rubber layer is not interposed, in this embodiment, this substantial adhesion length m is set to 6% or more of the tire radial cross-sectional height l, and the carcass ply 1 and its winding are Part 1
The shearing rigidity between the reinforcing braais 9 is improved to improve the side cut resistance. If it is less than 6%, it is not preferable because side cut resistance deteriorates. However, the substantial adhesion length m and the tire radial cross section. If the ratio (m/l) to the height (l) exceeds 21%, the weight of the carcass ply increases, which increases cost and deteriorates fuel efficiency and ride comfort, which is not preferable.

As described above, in the present invention, the end portion 1n of the reinforcing carcass 9 located on the outside of the tire can be fixed by the carcass ply 1 located on the inside of the tire that is wound around the ped wire 6 and fixed, and its rolled up portion 1'.
In the tire molding and curing process, the amount of heat shrinkage generated in the carcass ply 1 and the reinforced carcass ply 9 can be made almost equal, and as a result, as mentioned above, the side cut resistance is improved by a carcass structure with a 2-0 ply lock. This means that the tires can be maintained at the same level as the existing tires.

Here, the process by which the side cut resistance of the tire of the present invention can be maintained at the same level as that of a tire having a 2-0 ply lock carcass structure will be explained.

As a result of a detailed comparative study of conventional 2-0 ply lock tires and 1-1 ply lock tires, the present inventors found that during molding and curing, the carcass cord located inside the tire and the carcass cord located outside the tire shrink due to heat. They discovered that if there is too much difference in the amount, the resistance to external forces applied during sidecut-like fights will be significantly reduced.

In other words, if we take the intermediate elongation as a substitute value for the amount of heat shrinkage of the carcass cord during molding and vulcanization, and measure that of the carcass cord located inside the tire and that of the carcass cord located outside the tire, we can find that it depends on the material of the carcass cord. First, it was confirmed that the intermediate elongation of the carcass cord located on the outside of the tire was clearly large in the 1-1 ply lock, although there was no difference in the 2-0 ply lock. It was confirmed that the smaller the difference, the better.

Therefore, the inventors of the present invention have created a carcass structure that provides a reinforced carcass located on the outside of the tire with the same amount of heat shrinkage as the carcass ply 1 located on the inside of the tire during molding and vulcanization, and that is lightweight and has high productivity. As a result of various studies, we were able to make this possible for the first time with the carcass structure of the present invention described above.

Further, as a result of experiments, failures such as separation during running at the end 10a of the reinforced carcass ply 9, which was initially a concern in the radial tire of the present invention, did not occur, and the lateral rigidity of the bead portion was also lower than that of the conventional 2-0 ply described above. lock 1
Compared to 1-1 ply lock radial tires, there were no problems.

In the figure, 6 and 4 are belt reinforcing layers, 5 is a cap tread portion, and 7 is a bead toe portion.

Note that, as shown in FIG. 3, the bead filler rubber 8 may not be provided directly on the bead wire 6, but the bead filler rubber 8 may be provided on the bead wire 6 via the outside of the winding section of the carcass ply 1. Of course. Also, if necessary, a bead cover ply may be provided on the bead wire and bead filler.

Figure 4 shows the intermediate elongation of carcass ply 1 located on the inside of the tire and reinforced carcass ply 9 located on the outside of the tire in a 2-ply carcass radial tire with tire size 195/70 HRI4 and nylon 1260 d/2. It is a diagram in which the values of the difference ratio are plotted on the vertical axis and m/l are plotted on the horizontal axis. In other words, the vertical axis is (outer carcass intermediate elongation - inner carcass intermediate elongation) ÷ inner carcass intermediate elongation, where the intermediate elongation is the elongation (support) under a load of 6.8 kg. be.

According to this, when m/l is set to 15% or more, there is no difference in intermediate elongation between the inner and outer carcass as in the conventional 2-0 plylock, but when m/it is set to 3% or less, the intermediate elongation is It has become clear that, like the conventional 1-1 ply lock, a difference of about 20% occurs between the inner and outer carcass.

Figure 5 shows the same 195/70 HRI 4 tire as in Figure 4, with an internal pressure of 1.9 kg/crIL2, an impact load of 15 kg at the maximum tire position, and an impact height of 1 m, with an impact area of 2CIrL2. It is a figure showing the result of carrying out a destructive test by applying an impact with ionization, and it is cut off at 120 times. In other words, it can be said that the greater the number of impacts leading to breakage, the better the side cut resistance.

According to this, when m/l is set to 12% or more, the number of impacts is cut off at 120 times as in the conventional 2-0 ply lock, but when m/l is set to 3% or less, the number of impacts and strikes is reduced from the conventional 1-0 plylock.
It was confirmed that, like the 1-ply lock, it would break after 60 cycles or less.

Next, another embodiment of the present invention shown in FIG.
', the reinforcing carcass ply 9 located on the outside of the tire is inserted over the above-mentioned substantial contact length m, and the bead filler rubber 8 provided on the cap tread portion 5 side of the bead wire 6 is inserted from inside the bead filler rubber 8 through the bead wire 6. The reinforcing carcass ply 9 is sandwiched between the inside of the bead cover ply 11, which is arranged so as to wrap the bead wire 6 outward, and the outside of the carcass ply 1, which is located inside the tire, over a substantial contact length of m'. It is configured.

Note that this bead cover ply 11 is previously assembled integrally with the bead wire 6 and bead filler rubber 8 during the tire manufacturing process.

According to this structure, the separation resistance (durability) of the end portion 10 of the reinforced carcass ply 9 can be further improved as compared to that of the first embodiment described above, and the rigidity of the ped portion can be strengthened. In this case, a reinforcing carcass ply may be inserted between the bead cover ply and the inner carcass ply, aligned with the outside of the bead cover ply and the bead filler comb, and then wound inside from the outside force of the bead wire.

As described above, the present invention involves winding up only the carcass ply located on the inside of the tire around a bead wire, and connecting the reinforcing carcass ply located on the outside of the tire between this rolled up portion and the carcass ply located on the inside of the tire. Because it is constructed by inserting the ends of the
Since the reinforcing carcass ply 9 located on the outside of the tire is not rolled up around the bead wire 6 as in the case of a 0-ply lock, the width of the reinforcing carcass ply 9 located on the outside of the tire can be narrowed, making it different from that of a conventional 2-0 ply lock. Comparatively larger, the carcass weight can be reduced,
Moreover, in the molding process, the carcass ply winding process only needs to be done once, so the molding productivity is improved by the above-mentioned 2-2.
It is as good as the one with 0 ply lock.

Furthermore, in the present invention, as described above, since the reinforcing carcass ply 9 located on the outside of the tire is not rolled up, it is possible to prevent uni-7 ohmity failures and vulcanization failures around the bead caused by narrowing the winding width.

Furthermore, in the present invention, the end portion 10 of the reinforcing carcass 9 located on the outside of the tire can be fixed by the carcass ply 1 located on the inside of the tire and its rolled up portion 1', which is wound and fixed around the bead wire 6 as described above. Therefore, the amount of heat shrinkage occurring in the carcass ply 1 and the reinforced carcass ply 9 in the tire molding and vulcanization process can be made almost equal, and as a result, as mentioned above, the sizing and cut resistance is improved to that of the 2-0 ply lock. It can be maintained at the same level as a tire with a carcass structure.

Therefore, the present invention can significantly reduce the weight of the tire without impairing the side cut resistance and productivity of the tire.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional 2-ply carcass radial tire. Figure 1 is an explanatory cross-sectional view of a tire with a 2-0 ply lock carcass structure, and Figure 2 is a 1-ply carcass radial tire.
1 is an explanatory cross-sectional view of a tire having a one-ply lock carcass structure. 3 is a cross-sectional explanatory diagram of a radial tire according to an embodiment of the present invention, FIG. 34 is a cross-sectional explanatory diagram of a radial tire according to another embodiment of the present invention, and FIG. Ratio of difference in intermediate elongation between carcass and outer carcass (support)
), take In/l (%) on the horizontal axis, and take this ml
Figure 5 is a diagram showing the relationship between l and the ratio of the difference in intermediate elongation, with the vertical axis representing the number of side impact impacts and the horizontal axis representing m.
/7? It is a diagram showing the relationship between mll and the number of side impact impacts, taking (support)). 1... Carcass ply located inside the tire, 6...
- Bead wire, 9... Reinforced carcass ply located on the outside of the tire, 10... End of the reinforced carcass ply,
1'... The rolled-up part of the carcass ply located inside the tire. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Patent Attorney Kazuhiko Saishita (Figure 3, Figure 4, Figure 4)

Claims (1)

[Claims] In a two-ply carcass radial tire, only the carcass ply located on the inside of the tire is wound up around the peed wire, and between this rolled up portion and the carcass ply located on the inside of the tire, the end of the reinforcing carcass ply located on the outside of the tire is Radial tire 0 featuring