JP2019119413A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that can improve durability of a belt layer by suppress outer diameter growth of the layer and avoid edge-separation and wire-breakage due to use of a single steel wire, by using the single steel wire in an untwisted state as a reinforcing wire rod of the belt layer.SOLUTION: In the pneumatic tire, a plurality of layers of belt layers 7 having a plurality of reinforcing wire rods R inclining with respect to a tire circumferential direction are arranged at an outer periphery side of a carcass layer 4 in a tread part 1. The belt layer 7 includes two layers of main belt layers 72 and 73 arranged so that the reinforcing wire rods R cross each other between the layers. The reinforcing wire rod R of at least one layer of main belt layers 72 and 73 is constituted of a metal bundle 10 in which a plurality of single steel wires 11 are pulled parallely in one direction in an untwisted state and piled up in a tire radial direction, and wrapping wires 12 for binding are wrapped around the metal bundle 10. When a thickness d of each single steel wire 11 is 0.15 mm-0.35 mm and a driving interval wof the metal bundle 10 is 1.0 mm or more.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pneumatic tire provided with a belt layer on the outer peripheral side of a carcass layer, and more specifically, by using a single-wire steel wire in a non-twisted state as a reinforcing wire of the belt layer, the outer diameter growth is suppressed to suppress the belt. The present invention relates to a pneumatic tire capable of improving the durability of a layer and avoiding the occurrence of edge separation and wire breakage resulting from the use of a single wire steel wire.

  In heavy-duty pneumatic tires used for trucks, buses, etc., the same tire can be reused twice or more by retreading even if the tread portion is worn to the end of its life (see, for example, Patent Document 1) . In such a retread base tire, it is required to improve the durability of the belt layer. In order to improve the durability of the belt layer, it is necessary to suppress the growth of the outer diameter, and one of the measures is to reduce the initial elongation of the belt layer.

  As a method of reducing the initial elongation of the belt layer, it is conceivable to use a single-wire steel wire in a non-twisted state as a reinforcing wire of the belt layer (see, for example, Patent Documents 2 to 4). Since a single stranded steel wire in a non-twisted state does not cause elongation due to the twist structure, it is effective for suppressing the growth of the outer diameter. However, if the diameter of the single wire steel wire is increased to secure the total strength as a reinforcing wire of the belt layer, there is a disadvantage that the single wire steel wire is easily broken due to the out-of-plane bending deformation of the belt layer. On the other hand, if the diameter of the single-wire steel wire is reduced and more single-wire steel wires are arranged along the surface direction of the belt layer, the distance between the wires decreases and edge separation easily occurs in the belt layer. is there.

Japanese Patent Application Laid-Open No. 6-183224 Unexamined-Japanese-Patent No. 2004-161199 JP, 2010-111354, A Patent No. 4424822 gazette

  The object of the present invention is to suppress the outer diameter growth and improve the durability of the belt layer by using an untwisted single wire steel wire as a reinforcing wire of the belt layer, and an edge resulting from the use of the single wire steel wire An object of the present invention is to provide a pneumatic tire capable of avoiding the occurrence of separation and wire breakage.

A pneumatic tire according to the present invention for achieving the above object comprises a tread portion extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and these sidewall portions And a pair of bead portions disposed on the inner side in the tire outer diameter direction, and a carcass layer is mounted between the pair of bead portions, and the carcass layer is wound up from the inside to the outside around the bead cores of each bead portion. A pneumatic tire having a plurality of belt layers having a plurality of reinforcing wire members inclined with respect to the tire circumferential direction on the outer peripheral side of the carcass layer in the tread portion.
The belt layer includes two main belt layers arranged such that reinforcing wires cross each other between the layers,
The reinforcing wire of at least one main belt layer is composed of metal bundles in which a plurality of single wire steel wires are aligned in the same direction without twisting and are stacked in the tire radial direction, and bound around the metal bundles Wrapping wire is wound, the thickness d of each single wire steel wire is 0.15 mm to 0.35 mm, and the implantation distance w _{1 of the} metal bundle is 1.0 mm or more. is there.

In the present invention, reinforcement is performed by using a metal bundle in which a plurality of single wire steel wires are aligned in the same direction without twisting and stacked in the tire radial direction as a reinforcing wire member of at least one main belt layer. Since the initial elongation of the wire is substantially eliminated, the outer diameter growth can be suppressed to improve the durability of the belt layer including the main belt layer. In addition, by securing the total strength as the reinforcing wire in the form of a metal bundle, it is possible to reduce the thickness d of each single wire steel wire, so that wire breakage can be suppressed. Further, by stacking a plurality of single wire steel wire in the metal flux in the tire radial direction, it becomes possible to increase the interval w ₁ implanted metal flux, it is possible to suppress edge separation of the main belt layer. Further, since the binding wrapping wire is wound around the metal bundle, the integrity of the metal bundle can be enhanced to effectively function as a reinforcing wire.

  In the present invention, the tensile rigidity AE of each main belt layer is preferably 1800 kN / 50 mm or more. Thus, the growth of the outer diameter can be suppressed, and the durability of the belt layer including the main belt layer can be effectively improved.

It is preferable gap g ₁ of the single wire steel wire between the metal beam is 0.05 mm to 0.3 mm. Thereby, fretting between single wire steel wires in the metal bundle can be prevented, and durability of the main belt layer can be effectively improved.

The diameter d ₁ of the bundling wrapping wire is 0.1 mm to 0.3 mm, the pitch p ₁ wound bundling wrapping wire is preferably 4.0Mm～16.0Mm. In this way, in-plane shear deformation between single-wire steel wires is effectively suppressed and the tensile rigidity in the circumferential direction of the belt layer including the main belt layer is increased while minimizing the cost increase due to the addition of the binding wrapping wire. Can.

At least one of the pair of single wires steel wires adjacent in the tire radial direction in the metal bundle is wound wrapping yarn or lapping wire for the spacer, the diameter d ₂ of the wrapping yarn or wrapping wires for spacers 0.1mm~ is 0.3 mm, it is preferable pitch p ₂ wrapped wrapping yarn or wrapping wires for the spacer is 4.0Mm～16.0Mm. Thus, since the gap g ₁ of the single wire steel wire between the metal beam is sufficiently ensured, that prevents fretting of single wire steel wire between the metal flux, effectively improve the durability of the main belt layer it can.

In addition, the belt layer includes an auxiliary belt layer laminated to the main belt layer, and the reinforcement wire of the auxiliary belt layer is inclined in the same direction as the reinforcement wire of the adjacent main belt layer, and the reinforcement wire of the auxiliary belt layer When the inclination angle of the main belt layer to the circumferential direction of the main belt layer is set larger than the inclination angle of the reinforcing wire of the main belt layer to the circumferential direction of the tire, the reinforcing belts of the auxiliary belt layer are identical to each other in the untwisted state It is composed of metal bundles which are aligned in the radial direction and stacked in the tire radial direction, and a binding wrapping wire is wound around the metal bundles, and the thickness d of each single wire steel wire is 0.15 mm to 0. 0. is 35 mm, it is preferable driving distance w ₁ of the metal beam is 1.0mm or more.

Thereby, since the rigidity in the width direction of the auxiliary belt layer can be enhanced, shear deformation of the main belt layer can be suppressed, and the growth of the outer diameter can be suppressed. In addition, by securing the total strength as the reinforcing wire in the form of a metal bundle, it is possible to reduce the thickness d of each single wire steel wire, so that wire breakage can be suppressed. Further, by stacking a plurality of single wire steel wire in the metal flux in the tire radial direction, it becomes possible to increase the interval w ₁ implanted metal flux, it is possible to suppress edge separation of the auxiliary belt layer. Further, since the binding wrapping wire is wound around the metal bundle, the integrity of the metal bundle can be enhanced to effectively function as a reinforcing wire.

It is a meridional sectional view showing a heavy duty pneumatic tire according to an embodiment of the present invention. It is an expanded view which extracts and shows a belt layer of a pneumatic tire for heavy load consisting of an embodiment of the present invention. It is a perspective cross-sectional view which shows an example of the metal bundle which consists of multiple single wire steel wires. It is a perspective view showing a modification of a metal bundle consisting of a plurality of single wire steel wires. It is a perspective cross-sectional view which shows the other modification of the metal bundle which consists of multiple single wire steel wires. It is a side view which shows the metal bundle of FIG.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the attached drawings. FIG. 1 shows a heavy duty pneumatic tire according to an embodiment of the present invention, and FIG. 2 shows the belt layer thereof.

  As shown in FIG. 1, the pneumatic tire according to the present embodiment includes a tread portion 1 extending in the circumferential direction of the tire to form an annular shape, and a pair of sidewall portions 2 and 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed on the inner side in the tire radial direction of the side wall portions 2.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and has a structure in which the bead core 5 disposed in each bead portion 3 is wound up from the inside to the outside of the tire. A bead filler 6 made of a rubber composition having a triangular cross section is disposed on the outer periphery of the bead core 5.

  In the pneumatic tire, four belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing wire members R inclined with respect to the tire circumferential direction. The belt layers 7 include two main belt layers 72 and 73 in the center, and two auxiliary belt layers 71 and 74 disposed on the inner and outer sides of the main belt layers 72 and 73 in the tire radial direction. .

  As shown in FIG. 2, the main belt layer 72 on the inner side in the tire radial direction and the main belt layer 73 on the outer side in the tire radial direction are arranged so that the reinforcing wires R intersect each other between the layers. Further, the reinforcing wire R of the auxiliary belt layer 71 located inward in the tire radial direction is inclined in the same direction as the reinforcing wire R of the main belt layer 72 adjacent to the auxiliary belt layer 71, and the auxiliary belt is located outward in the tire radial direction. The reinforcing wire R of the layer 74 is inclined in the same direction as the reinforcing wire R of the main belt layer 73 adjacent to the auxiliary belt layer 74. The inclination angle β of the reinforcing wire R constituting the auxiliary belt layers 71 and 74 with respect to the tire circumferential direction is set larger than the inclination angle α of the reinforcing wire R constituting the main belt layers 72 and 73 with respect to the tire circumferential direction. More specifically, the inclination angle α of the reinforcing wire rod R constituting the main belt layers 72 and 73 is set, for example, in the range of 15 ° to 25 °, and the inclination angle of the reinforcing wire rod R constituting the auxiliary belt layers 71 and 74 β is set, for example, in the range of 50 ° to 90 °, and the difference (β-α) between the two is set, for example, in the range of 35 ° to 65 °. The inclination angle α of the reinforcing wire R of the main belt layers 72 and 73 and the inclination angle β of the reinforcing wire R of the auxiliary belt layers 71 and 74 are angles measured on the tire center line CL.

  In the pneumatic tire, a metal bundle 10 described later is used as a reinforcing wire R in at least one of the main belt layers 72 and 73. It is desirable that the metal bundle 10 be applied to both of the main belt layers 72 and 73, but a normal steel cord or the like can be used for a layer to which the metal bundle 10 is not applied.

  3 and 4 each show a metal bundle consisting of a plurality of single wire steel wires. In FIGS. 3 and 4, each of the plurality of metal bundles 10 has a structure in which the plurality of single wire steel wires 11 are aligned in the same direction without being twisted and stacked in the tire radial direction Tr. . It is preferable that the number of stacked single-wire steel wires 11 in the metal bundle 10 be two to five. Here, the "non-twisted state" means a state in which a plurality of single wire steel wires 11 are not substantially twisted together, and specifically, a state in which they are not twisted at a pitch of 200 mm or less, more preferably , Means not twisted at a pitch of 1000 mm or less. The metal bundles 10 are arranged at equal intervals in the main belt layers 72 and 73 along the tire width direction Tw (the surface direction of the main belt layers 72 and 73). A bundling wrapping wire 12 is wound around each metal bundle 10, and a plurality of single wire steel wires 11 are integrally bundled by the bundling wrapping wire 12. As the binding wrapping wire 12, a steel wire having a circular cross section is preferable.

The thickness d of each single wire steel wire 11 in the tire radial direction is set in the range of 0.15 mm to 0.35 mm. The distance w ₁ implanted metal beam 10 is set to more than 1.0 mm. Interval w ₁ implanted metal bundle 10 is a value measured in the cross section intersecting perpendicularly to the longitudinal direction of the single wire steel wire 11, the shortest distance of the metal beam 10 which is measured in the tire width direction Tw. Interval w ₁ implantation of thickness d and the metal bundle 10 of single wire steel wire 11 is a value that does not include the size of the bundling wrapping wire 12.

The cross-sectional shape of the single wire steel wire 11 is not particularly limited, and a circular shape as shown in FIG. 3 or a flat shape as shown in FIG. 4 can be adopted. In particular, if it can ensure 1.0mm or more as the interval w ₁ implantation of metal beams 10, it is preferable to adopt a flat shape is the ratio of the major axis to the minor axis is 3.0 or more. When the single-wire steel wire 11 has a flat shape, the gauges of the main belt layers 71 and 74 can be made thin, so weight reduction and cost reduction can be achieved. Moreover, when the single wire steel wire 11 has a flat shape, the collapse of the metal bundle 10 can be suppressed in the rubber pulling process. Although "flat" is a shape in which the major axis and the minor axis exist in the cross section of the single wire steel wire 11, it is preferable that the outer edge thereof is a curve or a straight line that is convex outward. For example, the outer edge may be formed of only a curve (ellipse), the outer edge may be formed of only a straight line (rectangle), or the outer edge may be formed of a straight line and a curve (substantially rectangular, track type) . The single wire steel wire 11 having a flat shape is disposed such that the major diameter side thereof is in the tire width direction Tw.

  FIGS. 5 and 6 show another modification of the metal bundle consisting of a plurality of single wire steel wires. 5 and 6, in at least one of the pair of single wire steel wires 11 adjacent in the tire radial direction Tr in the metal bundle 10, a wrapping yarn or wrapping wire 13 for a spacer is wound. While a binding wrapping wire 12 bundles a plurality of single wire steel wires 11, a wrapping yarn or wrapping wire 13 for a spacer is wound around one single wire steel wire 11. As the wrapping yarn or wrapping wire 13 for the spacer, organic fibers such as nylon fibers, polyester fibers, aramid fibers and the like, and single wire steel wires can be used. The wrapping yarn or wrapping wire 13 functions as a spacer between a pair of single wire steel wires 11 adjacent to each other.

According to the pneumatic tire described above, in at least one of the main belt layers 72 and 73, a plurality of single wire steel wires 11 are aligned in the same direction without being twisted as the reinforcing wire R and are stacked in the tire radial direction By using the metal bundle 10, since the initial elongation of the reinforcing wire R is substantially eliminated, the outer diameter growth can be suppressed to improve the durability of the reinforcing layer 7 including the main belt layers 72 and 73. . Further, by securing the total strength as the reinforcing wire R in the form of the metal bundle 10, the thickness d of each single wire steel wire 11 can be reduced, so that wire breakage can be suppressed. Further, by stacking a plurality of single wire steel wire 11 in the metal flux 10 in the tire radial direction, it becomes possible to increase the interval w ₁ implantation of metal beams 10, the edge separation of the main belt layer 72 and 73 It can be suppressed.

  Further, since the binding wrapping wire 12 is wound around the metal bundle 10, the integrity of the metal bundle 10 can be enhanced to effectively function as the reinforcing wire R. That is, by enhancing the integrity of the metal bundle 10, the tensile rigidity in the circumferential direction of the main belt layers 72 and 73 can be increased. Furthermore, when the metal bundle 10 is compressed in the longitudinal direction of the single wire steel wire 11, it is possible to suppress deformation such that the single wire steel wires 11, 11 are separated from each other. Further, since the metal bundle 10 is integrated by the binding wrapping wire 12, there is also an advantage that the manufacture of the belt member becomes easy.

  Here, when the thickness d of the single-wire steel wire 11 is less than 0.15 mm, cracking easily occurs in the single-wire steel wire 11 during rolling of the belt member, and conversely, when it is larger than 0.35 mm, the tire rolling There is a concern about the fatigue failure of the single wire steel wire 11 due to out-of-plane bending deformation. In particular, the thickness d of the single wire steel wire 11 is preferably 0.18 mm to 0.30 mm.

When driving distance w ₁ of the metal beam 10 is less than 1.0 mm, separation at the edge portion of the main belt layer 72 and 73 for spacing the single wire steel wire 11 is narrowed is concerned. In particular, the implantation interval w ₁ of the metal bundle 10 is preferably 1.2 mm or more. The upper limit of the driving interval w ₁ is set to 4.0mm for example.

In the pneumatic tire, the tensile rigidity AE of each of the main belt layers 72 and 73 is preferably 1800 kN / 50 mm or more. Thus, the growth of the outer diameter can be suppressed, and the durability of the belt layer 7 including the main belt layers 72 and 73 can be effectively improved. The tensile rigidity AE of the main belt layers 72 and 73 can be obtained by the following equation (1). In the following formula (1), A is the cross-sectional area [mm ² ] of the metal bundle 10, E is the elastic modulus [GPa] of the single wire steel wire 11 constituting the metal bundle 10, and C is the main belt layer 72, The number of the metal bundles 10 in each of the numbers 73 is the number [number / 50 mm].
AE [kN / 50 mm] = A [mm ² ] x E [GPa] x C [book / 50 mm] (1)

Here, if the tensile rigidity AE of the main belt layers 72 and 73 is less than 1800 kN / 50 mm, the deterioration rate of the coated rubber increases due to the increase in outer diameter growth, and as a result, the belt layer 7 including the main belt layers 72 and 73 The durability of the In particular, the tensile rigidity AE of the main belt layers 72 and 73 is desirably 2000 kN / 50 mm or more. The upper limit value of the tensile rigidity AE is not particularly limited, but is substantially limited by the restriction of the driving interval w ₁ of the metal bundle 10.

In the pneumatic tire, the gap g ₁ between the single wire steel wire 11, 11 in the metal flux 10 may is 0.05 mm to 0.3 mm. Gap g ₁ is the minimum value of the spacing between the single wire steel wires 11 which are stacked. When single wire steel wires 11 and 11 are in contact with each other, g ₁ = 0.0 mm. By the gap g ₁ between the single wire steel wire 11, 11 in the metal flux 10 is set to the above range, to prevent fretting between the single wire steel wire 11, 11 in the metal bundle 10, the durability of the main belt layer 72 and 73 Sex can be improved effectively.

Here, the gap g ₁ between the single wire steel wire 11, 11 in the metal bundle 10 is less than 0.05 mm, not to obtain the effect of preventing fretting and greater than 0.3mm Conversely, fretting It is too thick for prevention and leads to increased costs. In particular, it is desirable that a gap g ₁ between the single wire steel wire 11, 11 in the metal bundle 10 is 0.08Mm～0.25Mm.

In the pneumatic tire, the diameter d ₁ of the bundling wrapping wire 12 is 0.1 mm to 0.3 mm, the pitch p ₁ wound bundling wrapping wire 12 is good and is 4.0Mm～16.0Mm (Figure 6). Thereby, while minimizing the cost increase due to the addition of the binding wrapping wire 12, the in-plane shear deformation between the single wire steel wires 11, 11 is effectively suppressed, and the belt layer 7 including the main belt layers 72, 73 is obtained. The circumferential tensile rigidity can be enhanced.

Here, if the diameter d ₁ of the binding wrapping wire 12 is less than 0.1 mm, the effect of suppressing in-plane shear deformation between the single wire steel wires 11 and 11 decreases, and conversely, if it is larger than 0.3 mm As compared with the effect of suppressing the in-plane shear deformation between the single wire steel wires 11 and 11, the strength becomes excessive and the cost is increased. In particular, the diameter d ₁ of the binding wrapping wire 12 is preferably 0.12 mm to 0.25 mm.

In addition, if the winding pitch p ₁ of the binding wrapping wire is less than 4.0 mm, the effect of suppressing the in-plane shear deformation between the single wire steel wires 11 and 11 becomes excessive strength, which leads to an increase in cost. If it is larger than 16.0 mm, the effect of suppressing in-plane shear deformation between the single wire steel wires 11 and 11 is reduced. In particular, the winding pitch p ₁ of the binding wrapping wire is preferably 6.0 mm to 14.0 mm.

When adding the wrapping yarn or lapping wire 13 for spacer metal beam 10, the diameter d ₂ of the wrapping yarn or lapping wire 13 for the spacer is 0.1 mm to 0.3 mm, wrapping yarn or wrapping wires for spacer pitch p ₂ winding 13 is good and is 4.0Mm～16.0Mm (see FIG. 6). Thus, since the gap g ₁ of the single wire steel wire 11, 11 to each other in the metal flux 10 is sufficiently ensured to prevent fretting between the single wire steel wire 11, 11 in the metal flux 10, the main belt layer 72 and 73 Durability can be effectively improved.

Here, if the diameter d ₂ of the wrapping yarn or lapping wire 13 for the spacer is less than 0.1 mm, site rubber does not penetrate is generated a gap g ₁ between the single wire steel wire 11, 11 is too small, the reverse If it is larger than 0.3 mm, the thickness becomes excessive for preventing fretting, which leads to an increase in cost. In particular, the diameter d ₂ of the wrapping yarn or lapping wire 13 for the spacer is preferably a 0.12Mm～0.25Mm.

Further, the pitch p ₂ wrapped wrapping yarn or lapping wire 13 for the spacer is less than 4.0 mm, and saturation effect of preventing contact between the single wire steel wire 11, 11 is merely causes an increase in cost On the other hand, if it is larger than 16.0 mm, the single wire steel wires 11 and 11 may be in contact with each other by bending. In particular, the pitch p ₂ wrapped wrapping yarn or lapping wire 13 for the spacer is preferably a 6.0Mm～14.0Mm.

  In the pneumatic tire, the belt layer 7 includes the auxiliary belt layers 71 and 74 disposed on the inner and outer peripheral sides of the main belt layers 72 and 73, and the reinforcing wire R of the auxiliary belt layers 71 and 74 is adjacent to the main The belt layer 72, 73 is inclined in the same direction as the reinforcing wire R, and the inclination angle β of the auxiliary belt layers 71, 74 with respect to the tire circumferential direction of the reinforcing wire R is the tire with respect to the reinforcing wire R of the main belt layers 72, 73. When it is set larger than the inclination angle α, the metal bundle 10 (FIGS. 3 to 6) composed of the single wire steel wires 11 described above is used as the reinforcing wire R of the auxiliary belt layers 71 and 74. desirable. The metal bundle 10 used for the auxiliary belt layers 71 and 74 can be configured similar to that used for the main belt layers 72 and 73. Although it is desirable that the metal bundle 10 be applied to both of the auxiliary belt layers 71 and 74, a normal steel cord or the like can be used for a layer to which the metal bundle 10 is not applied.

According to the pneumatic tire described above, as the reinforcing wire R of the auxiliary belt layers 71 and 74, a plurality of single wire steel wires 11 are aligned in the same direction without twisting, and are stacked in the tire radial direction 10 By using these, the rigidity in the width direction of the auxiliary belt layers 71 and 74 can be enhanced, so that shear deformation of the main belt layers 72 and 73 can be suppressed, and the outer diameter growth can be suppressed. Further, by securing the total strength as the reinforcing wire R in the form of the metal bundle 10, the thickness d of each single wire steel wire 11 can be reduced, so that wire breakage can be suppressed. Furthermore, by stacking a plurality of single wire steel wires 11 in the metal bundle 10 in the radial direction of the tire, it is possible to increase the driving distance w ₁ of the metal bundle 10, so edge separation of the auxiliary belt layers 71 and 74 can be achieved. It can be suppressed.

  Further, since the binding wrapping wire 12 is wound around the metal bundle 10, the integrity of the metal bundle 10 can be enhanced to effectively function as the reinforcing wire R. That is, by enhancing the integrity of the metal bundle 10, the tensile rigidity in the circumferential direction of the auxiliary belt layers 71 and 74 can be increased. Furthermore, when the metal bundle 10 is compressed in the longitudinal direction of the single wire steel wire 11, it is possible to suppress deformation such that the single wire steel wires 11, 11 are separated from each other. Further, since the metal bundle 10 is integrated by the binding wrapping wire 12, there is also an advantage that the manufacture of the belt member becomes easy.

  Tire size 315 / 60R22.5, comprising a tread portion, a pair of sidewall portions and a pair of bead portions, a carcass layer is mounted between the pair of bead portions, and the carcass layer is a bead core of each bead portion A pneumatic structure in which a four-layer belt layer having a structure in which it is wound up from the inside to the outside of the tire and having a plurality of reinforcing wire members inclined with respect to the tire circumferential direction on the outer circumferential side of the carcass layer in the tread portion Using a bundle of metal wires stacked in the radial direction of the tire as a reinforcing wire member of at least one belt layer, in which a plurality of single wire steel wires are untwisted and aligned in the same direction, The tire of Examples 1-17 and Comparative Examples 2-9 which adopted the structure where the wrapping wire was wound was manufactured.

  For comparison, the tire according to the conventional example using the steel cord of 3 + 8 structure made of steel wire having a circular cross-sectional shape as the reinforcing wire of the belt layer, and the comparative example 1 using the single wire steel wire as the reinforcing wire of the belt layer. Made of tires.

In the conventional example, Examples 1 to 17 and Comparative Examples 1 to 9, the inclination angle of the reinforcing wire of the belt layer (1B), the inclination angle of the reinforcing wire of the belt layer (2B), the inclination of the reinforcing wire of the belt layer (3B) Angle, angle of inclination of reinforcing wire of belt layer (4B), Belt layer to which metal bundle is applied as reinforcing wire, number of single wire steel wire constituting the metal bundle, cross sectional shape of single wire steel wire, number of reinforcement wires, reinforcement Wire cross section, elastic modulus of single wire steel wire, tensile stiffness of reinforcing wire, width of reinforcing wire, thickness d of single wire steel wire, insertion distance w ₁ of reinforcing wire, tensile stiffness AE of belt layer, single wire steel wire Gap g ₁ between each other, diameter d ₁ of wrapping wire for binding, winding pitch p _{1 of} wrapping wire for binding, diameter d ₂ of wrapping yarn (wire) for spacer, wrapping pin for spacer Grayed yarn pitch p ₂ wrapped in (wire) were set as shown in Table 1-4. The four belt layers were designated as 1B to 4B in order from the inner side to the outer side in the tire radial direction. With respect to the inclination angle of the reinforcing wire of the belt layer, a positive value means downward sloping and a negative value means downward sloping. The same steel cord as in the conventional example was used for the belt layer to which no metal bundle is applied as the reinforcing wire.

  With respect to these test tires, the durability of the belt layer, the presence or absence of wire breakage, the growth in outer diameter, and the cost were evaluated by the following test methods, and the results are also shown in Tables 1 to 4.

Belt layer durability:
Each test tire is mounted on the prescribed rim of ETRTO, 75% of the prescribed air pressure of ETRTO, loaded with 1.4 times the prescribed load of ETRTO, and run on a drum tester at a traveling speed of 49 km / h The test was conducted. It traveled until separation occurred in the tread portion of the tire, and the travel distance was measured. The evaluation results are indicated by an index where the conventional example is 100. The larger the index value, the better the durability of the belt layer.

Wire breakage:
After the above durability test was conducted, the tire was disassembled, and the presence or absence of wire breakage in the belt layer was examined.

Outer diameter growth:
In the above-described durability test, the amount of growth of the outer diameter of the tire when traveling 10,000 km was measured. The evaluation results were shown using an inverse number of the measured value, and an index with the conventional example as 100. The larger the index value, the smaller the outer diameter growth means.

cost:
The cost of reinforcing wire of the belt layer was determined. The evaluation results are shown by using an inverse number of cost and an index where the conventional example is 100. The larger the index value, the lower the cost.

  As can be seen from these Tables 1 to 4, in comparison with the conventional example, all the tires of Examples 1 to 17 have little growth in outer diameter, the belt layer has excellent durability, and wire breakage in the belt layer is It did not occur.

  On the other hand, in the tire of Comparative Example 1, since the single wire steel wire is used alone, the driving interval can not be sufficiently secured, and the durability of the belt layer is deteriorated. On the other hand, in the tire of Comparative Example 2, since the thickness d of the single wire steel wire is too large, wire breakage occurs in the belt layer, and the durability of the belt layer is deteriorated. Moreover, the effect of improving the durability of a belt layer was not acquired with the tires of Comparative Examples 2-9.

DESCRIPTION OF SYMBOLS 1 tread part 2 side wall part 3 bead part 4 carcass layer 5 bead core 6 bead filler 7 belt layer 10 metal bundle 11 single wire steel wire 12 wrapping wire for binding 13 wrapping yarn for spacer or wrapping wire 71, 74 auxiliary belt layer 72, 73 main belt layer

Claims (6)

A tread portion extending in the circumferential direction of the tire and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed inward of the tire outer diameter direction of the sidewall portions A carcass layer is mounted between the pair of bead portions, and the carcass layer is wound up around the bead core of each bead portion from the inside to the outside of the tire, and the carcass layer of the tread portion In a pneumatic tire in which a plurality of belt layers having a plurality of reinforcing wire members inclined with respect to the tire circumferential direction are disposed on the outer circumferential side,
The belt layer includes two main belt layers arranged such that reinforcing wires cross each other between the layers,
The reinforcing wire of at least one main belt layer is composed of metal bundles in which a plurality of single wire steel wires are aligned in the same direction without twisting and are stacked in the tire radial direction, and bound around the metal bundles Wrapping wire is wound, the thickness d of each single wire steel wire is 0.15 mm to 0.35 mm, and the implantation interval w _{1 of the} metal bundle is 1.0 mm or more. tire.   The pneumatic tire according to claim 1, wherein the tensile rigidity AE of each main belt layer is 1800 kN / 50 mm or more. The pneumatic tire according to claim 1 or 2 gaps g ₁ single wire steel wire together in the metal beam is characterized by a 0.05 mm to 0.3 mm. Wherein the diameter d ₁ of the bundling wrapping wire 0.1 mm to 0.3 mm, according to claim 1 to 3 pitches p ₁ winding of the tie wrapping wire characterized in that it is a 4.0mm~16.0mm The pneumatic tire according to any one of the above. The metal beam and wrapping yarn or lapping wire for the spacer is wound on at least one of the pair of single wires steel wires adjacent in the tire radial direction in the diameter d ₂ of the wrapping yarn or wrapping wires for the spacer is 0.1mm a ～0.3Mm, pneumatic tire according to claim 1, the pitch p ₂ wrapped wrapping yarn or wrapping wires for the spacer is characterized in that it is a 4.0mm~16.0mm . The belt layer includes an auxiliary belt layer laminated to the main belt layer, and the reinforcement wire of the auxiliary belt layer is inclined in the same direction as the reinforcement wire of the adjacent main belt layer, and the reinforcement wire of the auxiliary belt layer The inclination angle of the main belt layer with respect to the tire circumferential direction is set larger than the inclination angle of the reinforcing wire of the main belt layer with respect to the tire circumferential direction
The reinforcing wire of the auxiliary belt layer is composed of a metal bundle in which a plurality of single wire steel wires are aligned in the same direction in a non-twisted state and stacked in the tire radial direction, and a wrapping wire for binding around the metal bundle and is wound, a thickness d 0.15mm~0.35mm of each single wire steel wire, according to claim 1 to 5 driving distance w ₁ of the metal beam is characterized in that at not less than 1.0mm The pneumatic tire according to any one of the above.

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