JP2009073396A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire for making both compatible in abrasion resistance, partial abrasion resistance and durability. <P>SOLUTION: This pneumatic tire is formed by successively laminating a belt layer 3 and a tread 4 outside in the tire radial direction of a crown part of a carcass 2 extending in a toroidal shape by straddling between a pair of bead cores 1. The belt layer 3 is composed of at least four layers including belts 5a-5c of three layers and a cap ply 6 composed of a reinforcing cord layer substantially arranged in parallel to the tire peripheral direction and arranged over the whole width or more of a pair of edge plies and/or the belts arranged in both end areas of the belt. Among the belt layer, the first belt layer positioned in the innermost layer and the second belt layer on its outside are composed of two layers 5a and 5b of the belts arranged in the mutually crossing direction to the tire peripheral direction, and the third belt layer on its outside is composed of an edge ply and/or a cap ply 6 of at least one layer, and the fourth belt layer on its outside is also composed of one layer 5c of the belt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic tire (hereinafter, also simply referred to as “tire”), and more particularly to a pneumatic tire for a passenger car according to an improved belt structure for reinforcing a crown portion.

  As a factor of tire wear resistance reduction, tread distortion is locally generated in the tire width direction with deformation of the crown portion at the time of tire contact. In order to suppress such local distortion, it is only necessary to increase the out-of-plane bending rigidity of the crown portion in the tire width direction.

  Conventionally, two crossing layers are applied to the steel belt of a radial tire, and in order to give a strong tagging effect in the tire circumferential direction, the arrangement is such that the angle with respect to the axis perpendicular to the tire equator is as large as possible. It is used. However, it is difficult to contribute to the rigidity in the width direction of the crown tire with the two-layered crossed steel belt arranged in the tire circumferential direction.

  On the other hand, in addition to the conventional two-layer steel belt structure, as a means to achieve both an increase in tire width direction out-of-plane bending rigidity and a circumferential tensile rigidity to obtain a tagging effect, the outermost layer position is positioned in the tire width direction. A three-layer steel belt structure has been proposed in which a steel cord layer having an angular arrangement close to is arranged. In this structure, the steel cord layer disposed in the outermost layer exhibits compression rigidity against deformation of the crown portion due to ground contact, and the out-of-plane bending rigidity in the tire width direction is increased.

  However, by simply adding a steel cord layer to the conventional two-layer steel belt structure, the steel cord layer having an angular arrangement close to the tire width direction will cause Poisson deformation in the tire width direction against tension in the tire circumferential direction. Suppressing, the circumferential tensile rigidity becomes excessive, and the rectangular ratio increases. In other words, the crown shoulder portion protrudes and leads to uneven wear of the shoulder portion.

For example, Patent Document 1 discloses a technique for applying three steel belt layers to a belt layer of a pneumatic tire for the purpose of improving wear resistance and steering stability.
JP 2001-199203 A (Claims etc.)

  The local distortion of the tread with respect to the tire width direction at the time of tire contact results from the fact that the crown portion has a weak width-direction rigidity and deforms with a small curvature. In order to suppress such local distortion, as described above, it is only necessary to increase the out-of-plane bending stiffness in the tire width direction of the crown member disposed in the crown portion.

  At the time of grounding, the crown member is subjected to out-of-plane bending in a direction in which the crown curvature becomes flat. Since the crown member has a gauge, the member on the inner side is pulled by this out-of-plane bending, and the member on the tread side is subjected to compressive strain. Therefore, in order to increase the widthwise out-of-plane bending rigidity of the crown portion, a member having compression rigidity in the tire width direction may be disposed in the outermost layer as close as possible to the tread side. Moreover, in order to exhibit compression rigidity efficiently, the angle arrangement | positioning near parallel to a carcass ply is good as much as possible.

  However, as described above, when a third belt layer having an angle close to the tire width direction is simply added to the conventional two-layer belt structure, the tire circumferential tensile rigidity of the belt becomes excessive. As a result, the ground contact shape deteriorates, resulting in uneven wear. In addition, there is a problem that interlayer shear strain in the tire width direction is generated between the steel belt layers of the second layer and the third layer, belt separation occurs, and durability is remarkably lowered. Accordingly, there has been a demand for establishment of a technique capable of improving the wear resistance without causing the occurrence of uneven wear and a decrease in durability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic tire that solves the conventional problems and achieves both wear resistance, partial wear resistance, and durability.

  As a result of intensive studies, the inventor added a belt layer in which steel cords are arranged in the tire width direction to the outside of the two-layer belt in the tire radial direction via a belt layer having a different structure. It has been found that the wear resistance can be improved without causing other problems, and the present invention has been completed.

That is, the pneumatic tire of the present invention has a carcass extending in a toroidal shape across a pair of bead cores embedded in a pair of left and right bead portions, and a belt on the outer side in the radial direction of the crown portion of the carcass. In a pneumatic tire formed by sequentially laminating layers and treads,
The belt layer is composed of a three-layer belt and a reinforcing cord layer arranged substantially parallel to the tire circumferential direction, and a pair of edge plies and / or a total width of the belt disposed in both end regions of the belt Comprising at least four layers including a cap ply disposed over the above,
Of the belt layers, the first belt layer located in the innermost layer and the second belt layer outside the belt layer are composed of two layers of the belt arranged in a direction crossing each other with respect to the tire circumferential direction. A third belt layer outside the belt layer is composed of at least one edge ply and / or cap ply, and a fourth belt layer outside the third belt layer is composed of one layer of the belt. It is a feature.

  In the present invention, the fourth belt layer is preferably made of a rubberized layer of steel cord. The fourth belt layer is preferably arranged so as to form an angle of 0 ° to 45 ° with respect to the tire width direction. More preferably, in the present invention, the first, second, and fourth belt layers are made of a steel cord rubberized layer, and the third belt layer is made of an organic fiber cord rubberized layer.

  According to the present invention, the configuration described above can increase the out-of-plane bending rigidity in the tire width direction of the crown portion of the pneumatic tire, thereby achieving an increase in the rigidity of the tread portion and an overall uniform deformation of the tread portion. Thus, improvement in wear resistance can be achieved. Accordingly, it is possible to realize a pneumatic tire with improved wear resistance without causing the occurrence of uneven wear and a decrease in durability as in the prior art.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In FIG. 1, sectional drawing of the pneumatic tire which concerns on one suitable embodiment of this invention is shown. As shown in the figure, a pneumatic tire 10 according to the present invention has a carcass 2 extending in a toroidal shape across a pair of bead cores 1 embedded in a pair of left and right bead portions 11, and a crown portion tire radius. A belt layer 3 and a tread 4 are sequentially laminated on the outer side in the direction.

  In the illustrated tire 10, the belt layer 3 includes three belts 5 a to 5 c and a reinforcing cord layer arranged substantially in parallel with the tire circumferential direction, and covers a substantially entire surface of the belt 5 a to 5 c. Of the belt layers, and the first belt layer located in the innermost layer and the second belt layer outside thereof are arranged in a direction intersecting with each other in the tire circumferential direction. It consists of two layers of belts 5a and 5b, the third belt layer on the outside thereof consists of the cap ply 6, and the fourth belt layer on the outside consists of one belt 5c. In FIG. 2, the top view which shows the lamination | stacking state of these belt layers 3 is shown.

  In order to suppress the increase in belt circumferential tensile rigidity and belt separation described above, the distance between the cross belt arranged in two layers and the belt having an angle arrangement close to the tire width direction may be increased. Conceivable. Therefore, in the present invention, a member made of a reinforcing cord layer arranged substantially parallel to the tire circumferential direction is arranged outside the two-layer belt, and an angle arrangement close to the tire width direction is taken outside thereof. By arranging the belt layer of the first layer, it becomes possible to prevent the occurrence of the above problems. Moreover, by setting it as such an arrangement | positioning, the width direction out-of-plane bending rigidity of a crown part can further be enlarged.

  In the present invention, between the two layers of crossing belts 5a and 5b and the belt 5c, instead of the cap ply 6 shown in the figure, a reinforcing cord layer arranged substantially parallel to the tire circumferential direction is formed. You may arrange | position a pair of edge ply arrange | positioned at the both ends area | region of 5a-5c (not shown). Further, both the cap ply and the edge ply may be arranged, and in any case, the intended effect of the present invention can be obtained. In the present invention, the belt layer is required to be at least four layers comprising a three-layer belt and a cap ply and / or an edge ply. It is also possible to configure with five or more layers by adding a cap ply to the outside of the belt.

  Moreover, in this invention, it is preferable to arrange | position the belt 5c used as a 4th belt layer so that the angle of 0 degrees-45 degrees may be made with respect to a tire width direction. As a result, the compression rigidity of the fourth belt layer can be effectively exerted to increase the out-of-plane bending rigidity of the crown portion in the tire width direction, and shear strain generated between the layers with the third belt layer can be suppressed. , Durability can be improved. If the angle of the belt 5c is larger than 45 °, the out-of-plane bending rigidity of the crown portion in the width direction is remarkably lowered, and the durability is also deteriorated.

  Further, the belt 5c is preferably made of a rubberized layer of steel cord. This is because the steel cord has a high compression rigidity and can efficiently increase the out-of-plane bending rigidity in the crown portion width direction. More preferably, the belts 5a to 5c constituting the first, second and fourth belt layers are formed of a rubberized layer of a steel cord, and the cap ply and / or the edge ply constituting the third belt layer are formed. It is formed by a rubberized layer of organic fiber cord. Here, as the organic fiber cord used for the cap ply and / or the edge ply, a conventional synthetic fiber such as nylon can be appropriately used, and is not particularly limited.

  In the pneumatic tire of the present invention, it is only necessary to satisfy the above conditions for the belt structure, and other details of the tire structure and the material of each member should be appropriately determined according to a conventional method as desired. And should not be restricted in particular. For example, the carcass 2 extends from the crown portion 12 through the sidewall portion 13 to the bead portion 11 and reinforces these portions, and is arranged in at least one layer. Further, a tread pattern is appropriately formed on the surface of the tread 4, and an inner liner (not shown) is disposed in the innermost layer of the tire.

Hereinafter, the present invention will be described in more detail with reference to examples.
A pneumatic tire in which a carcass extending in a toroidal shape across a pair of bead cores embedded in a pair of left and right bead portions is used as a skeleton, and a belt layer and a tread are sequentially laminated on the outer side of the crown portion in the radial direction of the tire. Were prepared by changing only the belt layer configuration as shown below. The tire size was 205 / 55R16.

<Conventional example 1>
As the first belt layer located in the innermost layer and the second belt layer outside the first belt layer, two layers of steel belts (cord structure: 1 × 5) arranged in an intersecting direction at an angle of ± 65 ° with respect to the tire circumferential direction × 0.23 mm, cord driving number: 36/50 mm), and the outer third belt layer is composed of a rubberized layer of nylon cord arranged substantially parallel to the tire circumferential direction. A cap ply arranged over the entire width was used.

<Conventional example 2>
The first belt layer and the second belt layer are the same as those of the conventional example, and as a third belt layer on the outer side, a rubberized layer of steel cords arranged substantially parallel to the tire width direction (angle 0 °). Steel belt (cord structure: 1 × 5 × 0.23 mm, cord driving number: 36/50 mm), and arranged as a fourth belt layer on the outer side thereof substantially parallel to the tire circumferential direction. A cap ply made of a rubberized layer of nylon cord and arranged over the entire width of the belt was used.

<Examples 1-4>
The first belt layer and the second belt layer are the same as in the conventional example, and the outer third belt layer is made of a rubberized layer of nylon cord arranged substantially parallel to the tire circumferential direction, and has a total belt width. A steel belt comprising a rubberized layer of steel cords arranged at an angle shown in Table 1 below with respect to the tire width direction as a fourth belt layer on the outer side of the cap ply arranged over the above. (Cord structure: 1 × 5 × 0.23 mm, cord driving number: 36/50 mm).

  Each of the obtained test tires was evaluated for wear resistance, partial wear resistance, and crack length in accordance with the following. The results are shown in Table 1 below.

<Abrasion resistance>
Each test tire was mounted on a standard rim defined by the JATMA standard, filled with an internal pressure corresponding to the maximum load capacity in JATMA YEAR BOOK, and mounted on a passenger car. The reciprocal of the amount of wear after traveling 5000 km on the paved road was obtained and indicated by an index display when the conventional example 1 was set as the reference 100. The higher the value, the better the wear resistance.

<Uneven wear>
Under the same conditions as the above-mentioned wear resistance evaluation, the reciprocal of the difference between the most worn part and the non-worn part in the tire cross-sectional shape after running for 5000 km is obtained, and the index display when the conventional example 1 is set as the reference 100 Indicated. The higher the value, the better the wear resistance.

<Crack length>
Each test tire was mounted on a standard rim defined by the JATMA standard, filled with an internal pressure corresponding to the maximum load capacity in JATMA YEAR BOOK, and mounted on a passenger car. After running 50000 km on the paved road, the tire is dissected and the width direction belt (third layer steel belt (conventional example 2: third belt layer, example: fourth belt layer)) crack length from the cord end investigated. Here, there is no problem in durability if the crack length is 5 mm or less. The results are expressed as ◯ for 5 mm or less and x for 5 mm or more.

＊１）従来例２のみ第３ベルト層の角度、それ以外は第４ベルト層の角度を示す。

* 1) Only the conventional example 2 shows the angle of the third belt layer, and other than that shows the angle of the fourth belt layer.

  As shown in Table 1 above, in the test tire of each example in which the steel belt in the tire width direction is arranged on the outer periphery of the two-layer crossing belt via a predetermined cap ply, the third-layer steel belt is All have improved wear resistance compared to the test tire of Conventional Example 1 that does not have, and the arrangement angle of the third-layer steel belt is within the range of 0 ° to 45 ° with respect to the tire width direction. In Examples 1 to 3, it was confirmed that the partial wear and durability were further improved.

1 is a cross-sectional view in the width direction showing a pneumatic tire according to an embodiment of the present invention. It is a top view which shows an example of the belt structure in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead core 2 Carcass 3 Belt layer 4 Tread 5a-5c Belt 6 Cap ply 10 Pneumatic tire 11 Bead part 12 Crown part 13 Side wall part

Claims (4)

An air formed by sequentially laminating a belt layer and a tread on the outer side in the tire radial direction of the crown of the carcass extending in a toroid shape across a pair of bead cores embedded in a pair of left and right bead portions. In entering tires,
The belt layer is composed of a three-layer belt and a reinforcing cord layer arranged substantially parallel to the tire circumferential direction, and a pair of edge plies and / or a total width of the belt disposed in both end regions of the belt Comprising at least four layers including a cap ply disposed over the above,
Of the belt layers, the first belt layer located in the innermost layer and the second belt layer outside the belt layer are composed of two layers of the belt arranged in a direction crossing each other with respect to the tire circumferential direction. A third belt layer outside the belt layer is composed of at least one edge ply and / or cap ply, and a fourth belt layer outside the third belt layer is composed of one layer of the belt. A featured pneumatic tire.   The pneumatic tire according to claim 1, wherein the fourth belt layer is made of a rubberized layer of a steel cord.   The pneumatic tire according to claim 1 or 2, wherein the fourth belt layer forms an angle of 0 ° to 45 ° with respect to the tire width direction.   The said 1st, 2nd and 4th belt layer consists of a rubberized layer of a steel cord, and the said 3rd belt layer consists of a rubberized layer of an organic fiber cord. Pneumatic tires.

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