JP2005280611A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having a belt and a band structure for improving a high-speed characteristic. <P>SOLUTION: This pneumatic tire 1 comprises a carcass 6 passing from a tread 2 through a side wall 3 and reaching a bead core 5, a belt layer 7 and a band layer 10 arranged inside the tread and outside the carcass. The belt layer is comprised of at least two belts of an inner belt and an outer belt. The inner and outer belts are comprised of steel cords crossing at a right angle with a tire equinoctial plane, upper band layers arranged at both ends of the axial direction of the tire of the belt and at a radial outward location, and a lower edge band 10a arranged inside in a radial direction. Each of the band cords is comprised of organic fibers. The band cords face opposite the belt cords and the equinoctial plane that overlap at the inner surfaces. The upper edge band 10b is arranged on the outer surface of the outer belt or arranged between the inner and outer belts and at the same time a tire axial width Wb of the upper edge band is set to be larger than a width Wa of the lower edge band. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire having a belt and band structure that is useful for improving high-speed running performance.

  Pneumatic tires, especially pneumatic tires for high-speed running, use a belt layer using steel cords to prevent expansion of the tread, and lift the belt layer due to centrifugal force associated with high-speed running, especially at the end of the belt layer In order to prevent the occurrence of edge loosening in which the belt layer edge relaxes due to repeated lifting and grounding, a band layer that suppresses the lifting is frequently used.

  As shown in FIG. 6, the upper band ply b and the lower band ply c are respectively arranged outside the both ends of the inner belt ply a1 and the outer belt ply a2 in the width direction as shown in FIG. A pneumatic radial tire that reinforces both end portions of the belt layer a is proposed (for example, see Patent Document 1).

  In this proposal, the band cords of the upper band ply b and the lower band ply c are opposite to the belt cords of the inner belt ply a1 and the outer belt ply a2 that are adjacent to each other on the inner peripheral side. Yes.

JP 2001-310605 A

  Although it can be inferred that Patent Document 1 can exert a temporary effect on the band ply, there is no specific description regarding the width of the upper and lower band plies in the tire axial direction. The width of the inner belt layer is from 10 mm to 25% of the inner belt layer, and the width of the lower band ply c is from 10 mm to 130% of the inner belt layer (including the full band) (Claims 2 and 3 of Patent Document 1). This suggests that the upper band ply b is rather wide.

  However, the present inventor has studied and developed various upper and lower band plies, and found that the width and narrowness of the band ply affect the edge ply looseness and can improve high-speed durability. Therefore, the present invention pays attention to the width of the upper and lower band plies, and an object of the present invention is to provide a pneumatic tire having a band structure useful for improving high-speed running performance.

In order to achieve the above object, the invention according to claim 1 is directed to a carcass using parallel carcass cords extending from the tread portion to the bead core of the bead portion through the sidewall portion, the inside of the tread portion, and the radius of the carcass. A pneumatic tire having a belt layer disposed on the outer side in the direction and a band layer disposed overlapping the belt layer,
The belt layer is composed of at least two belt plies including an inner belt ply on the carcass side and an outer belt ply arranged radially outwardly,
And the inner and outer belt plies include belt cords made of steel cords that intersect and incline in opposite directions with respect to the tire equatorial plane,
In addition, the band layer includes an upper edge band ply disposed at both ends in the tire axial direction of the belt ply and radially outward, and a lower edge band ply disposed radially inward, and The band cord of each edge band ply uses an organic fiber cord,
The band cord of the edge band ply is opposite to the belt cord of the belt ply that overlaps on the inner surface side of the tire equator,
And the upper edge band ply is arranged on the outer surface of the outer belt ply or between the inner and outer belt plies,
The width Wb of the upper edge band ply in the tire axial direction is characterized by being larger than the width Wa of the lower edge band ply.

In the invention according to claim 2, the ratio Wa / Wb between the width Wb of the upper edge band ply in the tire axial direction and the width Wa of the lower edge band ply is 0.70 to 0.90. The invention according to claim 3 is characterized in that the width of the outer belt ply in the tire axial direction is smaller than the width of the inner belt ply,
And the upper edge band ply is arranged on the outer surface of the outer belt ply, and the lower edge band ply is arranged between the inner and outer belt plies,
An outer end in the tire axial direction of the upper edge band ply protrudes from an outer end in the tire axial direction of the outer belt ply, and is positioned inward in the tire axial direction from an outer end in the tire axial direction of the lower edge band ply. It is characterized by doing.

In the invention according to claim 4, the width in the tire axial direction of the outer belt ply is smaller than the width of the inner belt ply,
The upper edge band ply is disposed between the inner and outer belt plies, and the lower edge band ply is disposed on the inner surface of the inner belt ply.
6. The invention according to claim 5, wherein an outer end in the tire axial direction of the upper edge band ply 1 projects outwardly from an outer end in the tire axial direction of the inner belt ply and the lower edge band ply. Is characterized in that the tire axial direction outer ends of the lower edge band ply and the inner belt ply are aligned at the tire axial position.

  In the invention according to claim 1, the band layer includes the upper edge band ply and the lower edge band ply, and the band cord of the edge band ply is opposite to the belt cord of the belt ply on the inside. . For this reason, especially when a torsional deformation occurs in the entire tread portion, such as when turning at a high speed, the belt cord and the band cord cross each other, so that distortion deformation at the edge portion of the belt layer can be suppressed, and both belt layers can be suppressed. The edge separation resistance of the belt layer is improved by preventing the edge portion from rising to the outer peripheral side. Moreover, since the width Wb of the upper edge band ply in the tire axial direction is larger than the width Wa of the lower edge band ply, the upper edge band ply effectively suppresses deformation of the lower edge band ply. In addition, the edge separation prevention function by the edge band ply as a whole can be enhanced in cooperation with the edge separation prevention effect, and the tire growth at the shoulder portion is effectively suppressed, improving the high speed running performance. To do. Further, as in the invention according to claim 2, the ratio Wa / Wb between the width Wb of the upper edge band ply in the tire axial direction and the width Wa of the lower edge band ply is set to 0.70 to 0.90. As a result, the effect of preventing the edge separation can be further enhanced.

  With the configuration of the invention according to claim 3, the outer end portion in the tire axial direction of the outer belt ply is covered with the upper edge band ply and the lower edge band ply from above and below, so that edge separation resistance is improved. In the invention according to claim 4, the wide upper edge band ply protrudes from the outer edge in the tire axial direction of the inner belt ply and the lower edge band ply. Since the axial width is larger than the outer belt ply, the outer edge of the inner belt ply, which is affected by the twist of the tread, is covered with the upper edge band ply, resulting in improved edge separation resistance. it can. Furthermore, the invention according to claim 5 is that the edge number of the edge band ply which is formed of organic fiber cords at the end of the belt ply is reduced by aligning the shoulder ends of the belt ply and edge band ply. Therefore, the strain is relieved and the occurrence of stress concentration is suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example in which the pneumatic tire 1 of the present invention is a radial tire for passenger cars. The pneumatic tire (hereinafter sometimes simply referred to as a tire) 1 passes from the tread portion 2 through the sidewall portion 3. A carcass 6 that reaches the bead core 5 of the bead portion 4, a belt layer 7 that is disposed on the radially outer side of the carcass 6, and a band layer 10 that overlaps the belt layer 7 are disposed.

  The carcass 6 is formed using one or more radial or semi-radial carcass plies in which the carcass cord is parallel to the tire equatorial plane C at an angle of about 70 to 90 °, for example, one layer in this embodiment. Yes. In this embodiment, the carcass ply is folded back inwardly and locked around the bead core 5 to the body portion 6A from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. A portion 6B is provided in series and is bridged between the bead portions 4 and 4. As the carcass cord, organic and inorganic fiber cords such as nylon, polyester, rayon, aromatic polyamide fiber, etc. are adopted in addition to steel cords.

  The belt layer 7 includes, for example, two or more belts including an inner belt ply 7a disposed on the outer surface of the carcass 6 and an outer belt ply 7b disposed on the outer side in the radial direction. It consists of ply. The belt plies 7a and 7b are formed by embedding a cord parallel body in which belt cords 7ac and 7bc (shown in FIG. 3) using steel cords are arranged in a topping rubber, and the inner and outer belt plies 7a and 7b. In this embodiment, the belt cords 7ac and 7bc are opposite to each other at angles αa and αb of 10 ° to 35 ° with respect to the tire equatorial plane C. In order to form the structure, the tread portion 2 is strongly reinforced to increase its rigidity.

  In the belt layer 7, the width W7b of the outer belt ply 7b in the tire axial direction is smaller than the width W7a of the inner belt ply 7a, and the width of the inner belt ply 7a is, for example, the grounding width WT. It is formed in the range of about 0.9 to 1.1. As a result, the outer end 7be of the outer belt ply 7b is positioned inward in the tire axial direction from the outer end 7ae of the inner belt ply 7a in the tire axial direction, and between the outer end 7be and the outer end 7ae, An exposed portion 7c that exposes the outer surface of the belt ply 7b is formed. The exposed portion 7c has an exposed length L7c in the tire axial direction of about 3 to 8% of the ground contact width WT, and maintains the rigidity balance of the shoulder end portion by setting the lengths of the belt plies 7a and 7b.

  The contact width WT refers to the width in the tire axial direction when the tire is rim-assembled on a regular rim and is grounded by applying a normal load. The regular rim is defined by a standard rim defined by JATMA and TRA. "Design Rim" or "Measuring Rim" specified by ETRTO, the normal internal pressure is the maximum air pressure specified by JATMA, the maximum value described in the TRA table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", or ETRTO "INFLATION PRESSURE" as defined in the above, 180 kPa for passenger car radial tires, and the normal load means the maximum load capacity defined by JATMA, the maximum value described in the above table of TRA, or "LOAD CAPACITY defined by ETRTO "

  The band layer 10 is a small edge ply disposed at both end portions in the tire axial direction of the belt layer 7, and a lower edge band ply 10 a radially inward and an upper edge positioned radially outward. Two edge band plies with the band ply 10b are used. Further, the ratio Wa / Wb between the width Wb of the upper edge band ply 10b in the tire axial direction and the width Wa of the lower edge band ply 10a is set to 0.70 to 0.90, and the upper edge band ply 10b is It is wider than the lower edge band ply 10a. The widths Wa and Wb of the edge band plies 10a and 10b refer to the width in the tire axial direction in a normal wearing state, and the width Wb of the upper edge band ply 10b is 12 to 35% of the ground contact width WT, preferably About 15 to 25%.

  1 to 3, the outer edge 10be of the upper edge band ply 10b in the tire axial direction is positioned at an intermediate position of the exposed portion 7c, preferably an intermediate position, and the outer end 7ae of the inner belt ply 7a. And the outer surface of the outer belt ply 7a extends inward in the tire axial direction. The lower edge band ply 10a has an inner portion in the tire axial direction sandwiched between the inner and outer belt plies 10a and 10b, and the outer end 10ae matches the outer end 7ae of the inner belt ply 7a. (“Match” means that a range of 5 mm is allowed in addition to a case where the difference between the outer edges is substantially about 0 to 1 mm). That is, the exposed surface 7c is covered, and as a result, the upper and lower edge band plies 10a and 10b are located between the outer end 10be of the outer belt ply 10b and the outer end 10be of the upper edge band ply 10b. Overlap and cover. The inner end 10bf of the upper edge band ply 10b in the tire axial direction extends inwardly beyond the inner end 10af of the lower edge band ply 10a. The extension length Lf is about 1 to 1/4 times the width Wb of the upper edge band ply 10b.

  As a result, the upper edge band ply 10b has an end portion of the outer belt ply 7b on the inner surface side, and the lower edge band ply 10a has an end portion of the inner belt ply 7a on the inner surface side. Since it covers from the outside, even if torsional deformation of the tread portion 2 occurs, distortion at the end of the belt layer 7 can be suppressed by the hoop effect, and edge separation can be reduced.

  Further, coupled with the fact that Wa / Wb is in the range of 0.70 to 0.90, between the outer end 10be of the outer belt ply 10b and the outer end 10be of the upper edge band ply 10b, The upper and lower edge band plies 10a and 10b overlap, and the inner end 10bf of the upper edge band ply 10b in the tire axial direction extends inwardly beyond the inner end 10af of the lower edge band ply 10a. It will be possible. As a result, it has been found that the rigidity balance at the shoulder portion can be appropriately improved and the high-speed running performance can be improved by suppressing the expansion due to the centrifugal force and the tire growth. As described above, the protruding amount L10b from the outer end 7be of the belt ply 7b outside the upper edge band ply 10b is set between the center of the exposed portion 7c and the outer end 7ae of the lower belt ply 7a. preferable. For example, the range is about 7 to 15 mm. If it is too small, the effect of suppressing distortion at the end of the outer belt ply 7b may be insufficient and tire growth may occur in the shoulder portion. If it is too large, the upper edge band plies 10b and 10a overlap with each other. As the value increases, the rigidity balance is inferior.

  As a result, the overall tension of the upper and lower edge band plies 10b, 10a is generated outwardly in the radial direction of the belt layer 7 where stress concentration is greatly generated due to torsional deformation of the tread portion 2 that occurs during high-speed running, turning, and the like. The effect is enhanced, the edge separation resistance is improved, the tire growth in the shoulder portion is suppressed, and the high-speed running performance can be improved. As described above, the upper edge band ply 10b is disposed on the outer surface of the outer belt ply 7b, and the lower edge band ply 10a is disposed between the first and second belt plies 7a and 7b. The upper edge band ply 10b covers the end portion of the outer belt ply 7b on the inner surface side, and the lower edge band ply 10a covers the end portion of the inner belt ply 7a on the inner surface side from the outside in the radial direction. Therefore, even if torsional deformation of the tread portion 2 occurs, distortion at the end of the belt layer 7 is suppressed by the hoop effect, and edge separation can be reduced.

  For this reason, the lower and upper edge band plies 10a, 10b are opposite to the tire equatorial plane C with respect to the belt cords 7ac, 7bc of the belt plies 7a, 7b overlapping on the inner side surfaces. That is, in this embodiment in which the upper edge band ply 10b is disposed on the outer surface of the outer belt ply 7b and the lower edge band ply 10a is disposed between the inner and outer belt plies 7a and 7b, the outer belt ply 7a is disposed on the inner surface. The band cord 10bc of the upper edge band ply 10b on the side is opposite to the belt cord 7bc with respect to the tire equator plane C, and an angle βb with respect to the tire equator plane C is 10 to 30 ° or more than 30 °. It is arranged in the range of 45 degrees or less. In order to prevent lifting of the belt cord 7bc, it is preferable to make the cords orthogonal to each other in order to prevent the opening between the belt cords 7bc and between the belt cords 7ac. However, excessively tilting the band cords 10ac and 10bc is manufactured. And the effect of increasing the circumferential rigidity by the cord itself is hindered. Therefore, from the viewpoint of manufacturing, a range of 10 to 30 °, and in some cases over 30 ° and 45 ° or less can be selected. The same applies to the belt cord 10ac of the lower edge band ply 10a where the inner belt ply 7a is located inside. However, the absolute values of the angles βa and βb are not the same, and can be changed according to the surfaces facing the vehicle inside and outside.

  Further, as the edge band ply 10a, 10b, various materials such as 66 nylon fiber or aramid fiber, polyester, or a modified fiber thereof can be adopted, but the heat shrinkable nylon fiber is used for both edges of the belt layer. It is frequently used because it can suppress the rise of the portion to the outer peripheral side and effectively suppress distortion deformation.

  4 and 5 show another embodiment. In the figure, the upper edge band ply 10b is disposed between the inner and outer belt plies 7a and 7b, and the lower edge band ply 10a is disposed on the inner surface side of the inner belt ply 7a. The outer end 10be of the upper edge band ply 10b in the tire axial direction protrudes beyond the outer end 10ae of the inner belt ply 7a and the outer end 10ae of the lower edge band ply 10a. ing. Also, the tire axial direction outer end 10ae of the lower edge band ply 10a and the tire axial direction outer end 7ae of the inner belt ply 7a coincide with each other in the tire axial direction position (the difference is substantially 0 to "coincidence"). In addition to the case of about 1 mm, a range of 5 mm is allowed).

  In this embodiment, the inner belt ply 7a is arranged on the inner side surface of the upper edge band ply 10b. The band cord 10bc of the upper edge band ply 10b and the belt of the inner belt ply 7a are arranged. The inclination angle αb, βb with respect to the tire equatorial plane C is reversed with respect to the cord 7ac. In this embodiment, the band cord 10ac of the lower edge band ply 10a is also inclined opposite to the belt cord 7ac of the inner belt ply 7a.

  As a result of having such a configuration, the inner belt ply 7a having a width Wa in the tire axial direction larger than the width Wb of the outer belt ply 7b and greatly affected by the stress concentration caused by the twist of the tread portion 2 is Covered by the wide edge band ply 10b, the upward effect in the radial direction of the tire is suppressed due to its tagging effect, and high-speed running performance is improved.

  The protrusion amount L10b1 of the outer edge 10be of the upper edge band ply 10b from the outer end 7ae of the belt ply 7a is, for example, in the range of about 3 to 15 mm. If it is less than 3 mm, the effect of suppressing distortion at the end of the inner belt ply 7a is not sufficiently exerted, so edge separation may occur. If it exceeds 15 mm, the rigidity of the belt part becomes excessive and rolling resistance increases. In addition, ride comfort is impaired.

  A tire having a tire size of 215 / 45ZR17 and having the configuration shown in FIG. 2 or FIG. 4 was prototyped based on the use of Table 1, and the high speed level of each sample tire was tested. The results are shown in Table 1. . In addition, the number of driving | injection means the number per 5 cm. “Reverse” in the cord angle of the band layer means that it is opposite to the cord direction of the belt ply located on the inner peripheral surface side.

  The test method was performed by a step speed method using a drum tester in accordance with a load / speed performance test defined by ECE30 under a rim (17 × 7JJ) and internal pressure (200 kPa). In the test, the running speed is sequentially increased and the speed when the tire breaks is displayed as an index with a comparative example being 100. A larger index is better.

1 is a tire meridian cross-sectional view illustrating an embodiment of the present invention. It is the expanded sectional view. It is the diagram which illustrates the belt ply and the edge band ply with the direction of the cord. It is tire meridian sectional drawing which illustrates other embodiment of this invention. It is the diagram which illustrates the belt ply and the edge band ply with the direction of the cord. It is a tire meridian sectional view of a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 7 Belt ply 7b inside belt layer 7a Belt ply outside 10 Band layer 10a Edge band ply 10b on lower edge band ply 10b

Claims (5)

A carcass using parallel carcass cords from the tread part through the sidewall part to the bead core of the bead part, a belt layer arranged inside the tread part and radially outside the carcass, and overlapping the belt layer A pneumatic tire having a band layer disposed,
The belt layer is composed of at least two belt plies including an inner belt ply on the carcass side and an outer belt ply arranged radially outwardly,
And the inner and outer belt plies include belt cords made of steel cords that intersect and incline in opposite directions with respect to the tire equatorial plane,
Moreover, the band layer is composed of an upper edge band ply disposed at both ends in the tire axial direction of the belt ply and radially outward, and a lower edge band ply disposed radially inward,
And the band cord of each edge band ply uses an organic fiber cord,
The band cord of the edge band ply is opposite to the belt cord of the belt ply that overlaps on the inner surface side of the tire equator,
And the upper edge band ply is arranged on the outer surface of the outer belt ply or between the inner and outer belt plies,
A pneumatic tire characterized in that the width Wb of the upper edge band ply in the tire axial direction is larger than the width Wa of the lower edge band ply.   The ratio Wa / Wb between the width Wb of the upper edge band ply in the tire axial direction and the width Wa of the lower edge band ply is 0.70 to 0.90. Pneumatic tires. The width in the tire axial direction of the outer belt ply is smaller than the width of the inner belt ply,
And the upper edge band ply is arranged on the outer surface of the outer belt ply, and the lower edge band ply is arranged between the inner and outer belt plies,
An outer end in the tire axial direction of the upper edge band ply protrudes from an outer end in the tire axial direction of the outer belt ply, and is positioned inward in the tire axial direction from an outer end in the tire axial direction of the lower edge band ply. The pneumatic tire according to claim 1 or 2, characterized in that: The width of the outer belt ply in the tire axial direction is smaller than the width of the inner belt ply, and the upper edge band ply is between the inner and outer belt plies, and the lower edge band ply is the inner belt ply. While being arranged on the inner surface of the belt ply,
3. The air according to claim 1, wherein an outer end in the tire axial direction of the upper edge band ply protrudes outward from an outer end in the tire axial direction of the inner belt ply and the lower edge band ply. Tire   The pneumatic tire according to any one of claims 1 to 4, wherein the tire axial direction outer ends of the lower edge band ply and the inner belt ply are aligned at the tire axial position.

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