JPS62251202A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve durability at a high speed by forming a reinforcing layer which is provided so as to cover a part of a belt layer in between a tread and said belt layer, with a ribbon type band body having a specific width and continuously winding said band body in the sectional direction of a tire. CONSTITUTION:A pneumatic tire 11 has a pair of beads 13, two layers of carcass layers 15 made of nylon cords 14 which are formed being spread over the beads 13, a belt layer 16 made of steel cords which is placed radially outside the crown part 15a of the carcass layer 15, a tread 17 which is placed radially outside the belt layer 16, and double layers (reinforcing layers) 20 placed so as to cover the both side end parts 16a of the belt layer 16. In such a structure, the double layer 20 is formed by a ribbon type band body 21 having a width W21 of 2-20mm. And, the starting part 21a in the circumferential direction of the band body 21 is placed on the outside of an actual ground contact part 23 in the sectional direction of the tire, and the band body 21 is continuously wound in the sectional direction of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic tire, and more particularly to improving the high-speed durability of a high-performance pneumatic tire that runs at high speed.

(Prior Art) Conventional high-performance pneumatic tires use a belt reinforcement structure that reinforces the belt layer in order to increase longitudinal stability during high-speed running and improve high-speed durability. The reinforcing layer 1 used in the conventional belt reinforcing structure includes the so-called cap layer 2, one layer 3, or a combination of both, as shown separately in Fig. 5.6. It is interposed between the belt layer 9 and a tread (not shown). The cap 112 shown in FIG. 5, which is not shown in the figure and is of a normal type except for the belt reinforcement structure shown in FIG. Consisting of organic fiber cord 6,
It is wound in two layers on the radially outer side of a belt layer 9 made of ordinary steel cord 8 with a predetermined width larger than the width of the belt layer 9, and the end portions 2a in the circumferential direction are overlapped for a predetermined length. A connecting portion 2b is formed over the entire width W2 of the layer 2. Moreover, the layer 3 shown in FIG. 6 is wound in two layers to cover the side end 9a of the belt layer 9, and is similar to the case of the cap layer 2 (the same components are given the same reference numerals and explained). (omitted), the terminal portions 3a in the circumferential direction are overlapped to form a connecting portion 3b across the entire width W1 of the layer 3.

(Problems to be Solved by the Invention) However, the connecting portion 2b of the cap layer 2 or the connecting portion 3b of the first layer 3 (hereinafter, tlbY portion 3b as a representative)
) causes a stiffness step in which the stiffness changes in the belt reinforcing structure of the tire, which significantly deteriorates the homogeneity of the pneumatic tire. Therefore, during high-speed driving, the load applied to the pneumatic tire causes large local heat generation in the vicinity of the connection part 3b of layer 3 at the ground contact part of the pneumatic tire, corresponding to the stiffness difference, and the tread in the vicinity Thermal deterioration of the rubber occurs, which further develops into peeling failure due to thermal decomposition of the rubber. On the other hand, connection part 3 of layer 3
b causes a peeling failure, which further progresses to a peeling failure of the belt layer 9. For these reasons, there is a problem in that the high-speed durability of the pneumatic tire 1 is significantly reduced.

Therefore, an object of the present invention is to solve these problems and improve the high-speed durability of a high-performance pneumatic tire during high-speed running.

(Means for Solving the Problems) A pneumatic tire according to the present invention includes at least one carcass layer consisting of a pair of beads, a cord spanning between the beads and arranged substantially in the cross-sectional direction of the tire, and a carcass layer. a belt layer disposed on the radially outer side of the crown portion of the tire; a tread disposed on the radially outer side of the belt layer so as to cover the belt layer; A pneumatic tire has a reinforcing layer made of organic fiber cords arranged substantially parallel to the tire circumferential direction, and the reinforcing layer is made of a ribbon-like band having a width of 2 to 20 mm, and the band is arranged in the circumferential direction of the tire. It is characterized in that the band is continuously wound in a spiral shape in the cross-sectional direction of the tire, and the circumferential end of the band is disposed outside the actual ground contact area of the tread in the cross-sectional direction of the tire.

Here, the reason why the width of the reinforcing layer band is 2 to 20 mm is 2.
If the width of the belt is less than 20cm, the width of the band is narrow (the work is almost the same as winding a single organic fiber cord in a spiral shape, and winding takes time and productivity decreases).
If the width is more than m-, not only will the circumferential end of the band be inside the actual ground contact area, but also the cord direction of the organic fiber cord of the band will be too inclined with respect to the tire circumferential direction. The so-called Kuga effect of the reinforcing layer is reduced. Another problem is that it is difficult to manufacture.

In addition, the actual contact area refers to the contact area where the tread surface actually contacts the road surface when a pneumatic tire is filled with a specified internal pressure and a specified load is applied, and the outside of the actual contact area in the cross-sectional direction of the tire is defined as the This refers to both valve sides that exceed the tire cross-sectional width W of the ground contact area.

(Function) The reinforcing layer of the pneumatic tire of the present invention is composed of a ribbon-shaped band, and the band is continuously wound in a spiral shape in the tire circumferential direction in the tire cross-sectional direction, and the reinforcing layer is formed of a ribbon-like band, and the band is continuously wound in the tire cross-sectional direction in the tire circumferential direction. Since the circumferential end of the band is located on the outside in the tire cross-sectional direction, there is no difference in rigidity caused by the connecting portion of the circumferential end of the band within the actual ground contact area of the pneumatic tire. Therefore, when running at high speeds, there is no local heat generation due to the load applied to the pneumatic tire, and #I separation failure due to thermal deterioration and thermal decomposition of the tread rubber does not occur, nor does it cause separation failure in the reinforcing layer and belt layer. Not at all.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1.2 is a diagram showing a first embodiment of a pneumatic tire according to the present invention. The pneumatic tire 11 (tire size 205/60R15) shown in FIG.
and a two-layer carcass layer 15 consisting of a nylon cord (polyamide organic fiber cord) 14 with a thickness of 1260 d/2, which is arranged across the beads 13 in the cross-sectional direction of the tire, and a crown portion 15a of the carcass layer 15. A belt layer 16 consisting of a steel cord of structure IX5 arranged on the radially outer side and a belt layer 16 on the radially outer side of the belt layer 16.
a tread 17 arranged to cover the tread t”17;
Both ends 16 of the belt layer 16 are placed between the belt JM1G and the belt JM1G.
Two layers (reinforcing layer) consisting of 1260 d/2 thick nylon cord (polyamide organic fiber cord) arranged almost parallel to the circumferential direction of the tire so as to cover a.
20. Layer 20 is shown in Figure 2 fa)
, as shown in (b), the width W of 5 dragons! It consists of a ribbon-shaped band 21 having a
1a are arranged on the outside of the actual ground contact portion 23 of the tread 17 in the cross-sectional direction of the tire, and the band 21 starts from there and spirals in the circumferential direction of the tire in close contact with each other in the cross-sectional direction of the tire and continues toward the center of the tire in a predetermined manner. The first layer is wound by a width W2° of (60 mm), and then folded back and the second layer is wound on the radially outer side of the first layer band 21 (indicated by arrow A in the figure).
The circumferential start end 21a and the end end 21b of the tread 17 are provided so as to be located outside the actual ground contact portion 23 (width W2.) of the tread 17 in the tire cross-sectional direction. Therefore, layer 2
The band 21 of 0 is continuously wound in the tire circumferential direction on the inside of the actual ground contact portion 23 (width W23), and has a rigidity caused by having a connecting portion such as a circumferential starting end 21a or a terminal end 21b. There are no steps.

Next, a second embodiment of the present invention will be described.

In the second embodiment of the pneumatic tire according to the present invention shown in FIG. 3, a belt layer 16 and a tread 1 (not shown)
This is a case where two cap layers 25 are present as reinforcing layers between the cap layer 7 and the cap layer 7. Components that are the same as those in the first embodiment are given the same reference numerals, and only necessary details will be explained.

The camp layer 25 is composed of a ribbon-shaped band 21 having a width WzI of 5, and the band 21 extends circumferentially outward in the tire cross-sectional direction of the actual ground contact area (width W z 3 ) at one end side 25a of the cap layer 25. It has a starting end 21a, and continues spirally on the outside of the belt layer 16 in the tire circumferential direction toward the other end side 25b of the camp layer 25 with a width W2. of 180@m. The first layer is wound around the first layer, and then the second layer is folded back from the other end side 25b and wound around the radially outer side of the first layer up to the one end side 25a (indicated by arrow B) to form the circumferential end portion 21b. It is arranged at approximately the same position as the starting end 21a.

The inner side of the actual grounding portion 23 does not have a rigidity step that occurs due to the presence of a connecting portion. Everything other than the above is the same as the first embodiment.

Next, a third embodiment of the present invention will be described.

In the third embodiment of the pneumatic tire according to the present invention shown in FIG. 4, a belt layer 16 and a tread 1 (not shown)
This is the case where one cap layer 29 is provided as a reinforcing layer between the cap layer 7 and the cap layer 7. Components that are the same as those in the second embodiment are given the same reference numerals. In the cap layer 29, the band member 21 is located at one end 29a of the cap layer 29 and at the actual ground contact portion 23 (width W2).
It has a circumferential starting end 21a on the outside in the tire cross-sectional direction, and has a circumferential ending end 21b at the other end 29b of the cap layer 29. Therefore, there is no rigidity step inside the actual ground contact portion 23.

Everything other than the above is the same as the second embodiment.

In addition, in the embodiments other than those described above, a case has been described in which a single layer or a cap layer is used alone as a reinforcing layer, but in the present invention, a single layer and a cap layer may be used in combination at the same time.

Next, test tires (tire size 205/60R15
) was prepared and the effects of the present invention were confirmed. The test tires were manufactured in the same manner as described in the first and second examples and the prior art using a single layer or a cap layer as the reinforcing layer as shown in the following table.

In the test, the tire was filled with an internal pressure of 2.3 kg/crl, and the JI
A normal high-speed durability test (using an indoor drum testing machine) was conducted under the S-specified load, and failure conditions were observed.

The test results are shown in the following table. The index is shown with the comparative example as 100, and the larger the value, the better.

(This page, blank space below) As shown in the diagram, the test results show that the high-speed durability performance of both the first and second examples was significantly improved compared to the comparative example.
The failure occurred at a location unrelated to the connection of the reinforcing layer.

(Effects) As described above, according to the present invention, it is possible to prevent the occurrence of failures in the connecting portions of the reinforcing layer or the cap layer, and it is possible to significantly improve high-speed durability performance.

[Brief explanation of drawings]

1.2 is a diagram showing a first embodiment of a pneumatic tire according to the present invention, FIG. 1 is an overall sectional view thereof, and FIG.
) is a conceptual perspective view of the main part, and FIG. 2(t)) is a conceptual cross-sectional view of the main part. FIG. 3(a), (bl is the second embodiment of the present invention)
FIG. 3+81 is a perspective conceptual diagram of the main part, and FIG. 3 (bl is a cross-sectional conceptual diagram of the main part.
Figures (a) and (b) are diagrams showing a third embodiment of the present invention, and Figure 4 (al is a perspective conceptual diagram of the main part thereof, and Figure 4 (b) is a conceptual cross-sectional diagram of the main part. Figure 5.6 is a diagram showing the main parts of a conventional pneumatic tire, Figure 5 is a perspective view of the main part when a camping layer is used, and Figure 6 is a diagram showing the main part when a single layer is used. It is a perspective view of essential parts. 11... Pneumatic tire, 13... Bead, 14... Nylon cord (organic fiber cord),
15...Carcass layer, 15a...Crown portion, 16...Belt layer, 16a...Side end portion, 17...1- Red, 20... One layer (reinforcement layer), 21...
...Band body, 21a... Circumferential start end (circumferential end), 21
b...Opening direction end part (circumferential direction end part), 23...
... Actual ground contact part, 25.29 ... Camping layer (reinforcement layer), 25a
...One end side, 25b...Other end side.

Claims (1)

[Claims] at least one carcass layer consisting of a pair of beads, a cord spanning between the beads and arranged substantially in the cross-sectional direction of the tire, a belt layer arranged radially outward of the crown portion of the carcass layer, and a radially outer side of the belt layer. a tread arranged to cover the belt layer; and a reinforcing layer made of organic fiber cords arranged substantially parallel to the tire circumferential direction so as to cover at least a portion of the belt layer between the tread and the belt layer. In pneumatic tires, the reinforcement layer is 2 to 20 mm.
The band is made of a ribbon-shaped band having a width of A pneumatic tire characterized by arranging circumferential ends.