JP6835566B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

In the pneumatic radial tire, it is proposed in Patent Document 1 below that a cord reinforcing layer including a cord such as a nylon cord or a steel cord is provided along the winding portion of the carcass ply in order to improve the durability of the bead portion. There is.

By providing and reinforcing the cord reinforcing layer around the winding portion of the carcass ply in this way, the distortion of the winding end of the carcass ply can be dispersed, but the rigidity of the cord reinforcing layer is arranged around the bead portion. Since it is extremely higher than the rubber, stress strain is concentrated on the end of the cord reinforcing layer, and the durability of the bead portion tends to decrease.

In Patent Document 2 below, it is proposed that a ply cord arranged in the end region of the winding portion is provided in a wavy shape in order to suppress the separation of the winding portion of the carcass ply. According to Patent Document 2, the carcass cord included in the end region of the winding portion follows the deformation of the surroundings without directly bearing the tension due to the expansion and contraction of the wave shape, and as a result, the winding portion reaches the end region. It is disclosed that stress concentration can be relaxed and separation can be suppressed. However, Patent Document 2 does not suggest that the ply cords provided in a wavy shape are arranged so as to intersect each other to increase the rigidity.

Japanese Unexamined Patent Publication No. 2016-43815 JP-A-2009-269426

The present invention has been made in view of the above points, and an object of the present invention is to provide a pneumatic tire capable of improving the durability of the bead portion.

The pneumatic tire of the embodiment includes a pair of bead portions having a bead core and bead fillers arranged on the tire radial outer side of the bead core, a main body portion provided between the pair of bead portions, and the main body. An upply having a winding portion extending from the portion and being folded from the inside to the outside in the tire width direction around the bead core and wound outward in the tire radial direction along the bead filler, and provided on the tire outer surface side of the upply. In a pneumatic tire provided with a down ply having a winding laminated portion overlapping the winding portion, the up ply and the down ply are a ply cord arranged in a direction orthogonal to the tire circumferential direction and the ply cord. The ply cord of the up-ply and the down-ply is provided with a coated rubber covering the ply cord, and the portion of the bead filler located outside in the tire width direction has a wavy shape extending in the tire radial direction with an amplitude in the tire circumferential direction. The winding portion and the winding laminated portion are overlapped so that the portions provided in the wavy shape intersect each other in the side view of the tire.

In a preferred embodiment of the present invention, the winding portion and the winding laminated portion may be overlapped by shifting the phase of the portion provided in the wavy shape.

In another preferred embodiment of the present invention, the wave shape provided on the ply cord of the winding portion may have a longer wavelength toward the outer side in the tire radial direction.

Further, in another preferred embodiment of the present invention, the wave shape provided on the ply cord of the winding portion may have a smaller amplitude toward the outer side in the tire radial direction.

In the pneumatic tire of the embodiment, the up-ply and the down-ply are overlapped on the outer side of the bead filler in the tire width direction so that the ply cords provided in a wavy shape intersect each other, so that the durability of the bead portion is improved. Can be improved.

A tire meridian semi-cross-sectional view showing a pneumatic tire of the present embodiment. The bead core, the bead filler, and the carcass ply of the pneumatic tire of FIG. 1 are viewed from the side of the tire. It is the figure which looked at the ply cord provided in the winding-up part of the up-ply of the pneumatic tire and the winding-up stacking part of the down ply of the modified example from the side of the tire. It is the figure which looked at the ply cord provided in the winding part of the up-ply of the pneumatic tire and the winding laminated part of the down-ply which concerns on another modified example from the side of the tire.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a tire meridional cross-sectional view showing an example of a pneumatic tire (hereinafter, referred to as “tire”) 10 of the first embodiment, and shows a half cross section in a state of being mounted on a rim flange 1 of a specified rim. ..

In the present specification, the tire width direction is a direction parallel to the tire rotation axis, which is synonymous with the tire axis direction, is indicated by reference numeral Y in the figure, and the inside and outside of the tire width direction are indicated by reference numerals Y1 and Y2, respectively. Shown. The tire radial direction (radial direction) is a direction perpendicular to the tire rotation axis, and is indicated by reference numeral Z in the figure, and the inside and outside of the tire radial direction are indicated by reference numerals Z1 and Z2, respectively. Further, it is a direction on the circumference centered on the tire rotation axis, and is indicated by reference numeral R in the figure.

The tire 10 of the present embodiment includes a pair of left and right bead portions 11 provided on both sides in the tire width direction Y, a pair of sidewall portions 14 extending outward in the tire radial direction from the bead portions 11, and left and right sidewall portions 14. A tread portion 16 provided between both sidewall portions 14 so as to connect the radial outer end portions to each other is provided.

The bead portion 11 has an annular bead core 12 formed of a convergent body obtained by laminating and winding rubber-coated bead wires, and a rubber bead filler 13 arranged on the tire radial outer side Z2 of the bead core 12. The bead filler 13 is made of hard rubber and has a triangular cross section narrower toward the tip side extending from the maximum tire width position to the outer Z2 in the tire radial direction.

Inside the tire 10, two toroid-shaped carcass plies 20A and 20B are provided so as to be bridged between the pair of bead portions 11. The two carcass ply 20A and 20B are composed of two pieces, an up ply 20A on the inner surface side of the tire and a down ply 20B provided on the outer side (that is, the outer surface side of the tire). The up-ply 20A and the down-ply 20B reach the bead portion 11 from the tread portion 16 through the sidewall portions 14 on both sides, and both ends of the bead portion 11 are locked.

A belt 30 is provided on the outer surface side of the tire of the down ply 20B in the tread portion 16. The belt 30 has a plurality of cords (for example, steel cords) coated with rubber, and the tread portion 16 is reinforced by the outer circumferences of the two carcass plies 20A and 20B. A tread rubber 32 having an outer surface as a ground contact surface is provided on the outer side in the tire radial direction from the belt 30.

On the inner surface side of the tire of the upply 20A, an inner liner 34 as an air-resistant rubber layer constituting the inner peripheral surface of the tire 10 is provided. The sidewall portion 14 is provided with sidewall rubber 33 forming the outer wall surface of the tire 10 on both sides of the down ply 20B in the tire width direction Y.

A rim strip 40 is provided on the outer side Y2 of the bead portion 11 in the tire width direction. The upper part of the rim strip 40 is in contact with the lower part of the sidewall rubber 33. The lower portion of the rim strip 40 enters the inner Z1 in the tire radial direction from the bead core 12 and is in contact with the inner liner 34. The rim strip 40 forms the outer surface of the tire around the bead portion 11, and the tire 10 comes into contact with the rim flange 1 when the rim is assembled.

A rim line 35 is provided as a small protrusion at a predetermined position on the tire surface. The rim line 35 is a line for confirming that the tire 10 and the regular rim are concentric when the tire 10 is mounted on the regular rim. For that purpose, the rim line 35 is provided over one circumference in the tire circumferential direction, and is a circle centered on the rotation axis of the tire 10. The predetermined position where the rim line 35 is provided is a position where the rim line 35 protrudes outward in the tire radial direction by a certain distance from the outer circumference of the flange of the regular rim. Usually, the rim line 35 is provided at the boundary portion between the rim strip 40 and the sidewall rubber 33 on the tire surface.

In the tire 10 having such a configuration, the upply 20A wraps the main body portion 21A provided between the pair of bead portions 11 and forming the skeleton of the tire, and the bead core 12 and the bead filler 13 extending from the main body portion 21A. It also has a winding portion 22A that is folded back from the inner Y1 to the outer Y2 in the tire width direction around the bead portion 11.

The winding portion 22A of the upply 20A extends to the outer side Z2 in the tire radial direction along the outer side surface in the tire width direction of the bead core 12 and the bead filler 13. The tip of the hoisting portion 22A (that is, the tire radial outer end of the hoisting portion 22A) is the hoisting end 22AE, beyond the upper end (that is, the tire radial outer end) 13A of the bead filler 13 and inside the sidewall portion 14. It ends with.

The down ply 20B is provided between the pair of bead portions 11 on the tire outer surface side of the up ply 20A. The down ply 20B has a main body laminated portion 21B that overlaps the main body portion 21A of the up ply 20A in the sidewall portion 14 and the tread portion 16, and a winding laminated portion 22B that overlaps the winding portion 22A of the up ply 20A in the bead portion 11. The tip 20BE of the tire radial inner Z1 of the down ply 20B is located on the tire width outer side Y2 of the bead core 12, and the end of the tire radial inner Z1 of the down ply 20B overlaps with the bead core 12 in the tire radial direction Z.

As shown in FIG. 2, the up-ply 20A and the down-ply 20B have a plurality of ply cords 23A and 23B provided at intervals in the tire circumferential direction R, and a coating rubber 24A covering the plurality of ply cords 23A and 23B. , 24B and so on. As the ply cords 23A and 23B, metal cords such as steel cords and organic fiber cords such as polyester and nylon are used.

Specifically, the ply cord 23A of the up-ply 20A includes a cord main body portion 23A1 provided in the main body portion 21A and a cord winding portion 23A2 provided in the winding portion 22A. The cord main body 23A1 is arranged at intervals in the tire circumferential direction R, and extends along a direction substantially orthogonal to the tire circumferential direction R. The cord winding portion 23A2 has a wave shape extending in the tire radial direction while meandering with an amplitude in the tire circumferential direction R.

The ply cord 23B of the down ply 20B includes a cord main body portion 23B1 provided in the main body laminated portion 21B and a cord winding portion 23B2 provided in the winding laminated portion 22B. The cord main body 23B1 is arranged at intervals in the tire circumferential direction R, and extends along a direction substantially orthogonal to the tire circumferential direction R. The cord winding portion 23B2 has a wave shape extending in the tire radial direction while meandering with an amplitude in the tire circumferential direction R.

The cord winding portion 23A2 of the upply 20A and the cord winding portion 23B2 of the downply 20B are arranged in a mesh pattern so as to intersect each other in the side view of the tire as shown in FIG.

As a method of crossing the cord winding portion 23A2 of the up-ply 20A and the cord winding portion 23B2 of the down-ply 20B, the cord winding portion 23A2 and the cord winding portion 23B2 have a wavy phase (that is, a tire) as illustrated in FIG. In addition to superimposing the up-ply 20A and the down-ply 20B by shifting the position in the radial direction), for example, the cord winding portion 23A2 and the cord winding portion 23B2 can have different wave-shaped wavelengths and amplitudes to wind the cord. The portion 23A2 and the cord winding portion 23B2 can be crossed.

The ply cords 23A and 23B provided on the up-ply 20A and the down-ply 20B are arranged, for example, at intervals of 0.2 to 1.2 mm in the tire circumferential direction R, and the wave shape of the cord winding portions 23A2 and 23B2 is It is preferable that the amplitude is 0.5 mm or more and the wavelength is in the range of 4.0 mm to 20 mm. Further, when the cord winding portion 23A2 and the cord winding portion 23B2 shift the phase of the wave shape and intersect the cord winding portions 23A2 and 23B2 with each other, the phase difference of the wave shape is preferably in the range of 140 ° to 220 °. ..

In this specification, the distance between the ply cords 23A and 23B and the wave-shaped amplitude, wavelength, and phase difference of the cord winding portions 23A2 and 23B2 are measured in a free state before assembling the pneumatic tire to the rim. The value.

In the tire 10 of the present embodiment, the cord winding portion 23A2 of the up-ply 20A and the cord winding portion 23B2 of the down-ply 20B located outside the bead filler 13 in the tire width direction are provided in a wavy shape, respectively, and in the tire side view. The up-ply 20A and the down-ply 20B are overlapped so as to intersect each other. Therefore, the ply cords 23A and 23B form a mesh structure on the outer side Y2 of the bead filler 13 in the tire width direction in which a large strain is likely to be concentrated when the tire is deformed, so that the upply 20A and the downply 20B are significantly increased in rigidity. This makes it possible to improve the durability around the bead portion 11.

Moreover, in the present embodiment, even in a so-called radial tire in which the ply cord 23A of the up ply 20A and the ply cord 23B of the down ply 20B are arranged in a direction substantially orthogonal to the tire circumferential direction R, the bead filler 13 The ply cords 23A and 23B can be locally arranged in the mesh structure on the outside in the tire width direction to suppress deformation in the tire circumferential direction R.

(Change example 1)
In the above embodiment, the case where the wave shape provided in the cord winding portions 23A2 and 23B2 of the up-ply 20A and the down-ply 20B does not change in the tire radial direction Z and repeats the same shape has been described, but the cord winding portions 23A2 and 23B2 have been described. The provided wave shape may change in the tire radial direction Z.

Specifically, the wave shapes provided in the cord winding portions 23A2 and 23B2 of the up-ply 20A and the down-ply 20B change so that the wavelength becomes longer toward the outer Z2 in the tire radial direction as shown in FIG. Alternatively, as shown in FIG. 4, the amplitude may be changed so as to go toward the tire radial outer Z2, and the amplitude may be smaller as the tire radial outer Z2 has a longer wavelength. May change to.

Further, the wave shape provided in the cord winding portions 23A2 and 23B2 may change in the tire radial direction Z, but the wave shape provided in at least one of the cord winding portions 23A2 and 23B2 is in the tire radial direction Z. It may change. For example, even if the wave shape provided in the cord winding portion 23B2 of the down ply 20B does not change in the tire radial direction Z and the wave shape provided in the cord winding portion 23A2 of the up ply 20A changes in the tire radial direction Z. Good.

By changing the wave shape provided in the cord winding portions 23A2 and 23B2 in this way, the locations where the cord winding portions 23A2 and 23B2 intersect with each other can be gradually reduced toward the outer Z2 in the tire radial direction. .. As a result, the rigidity of the winding portion 22A and the winding laminated portion 22B gradually decreases toward the outer side Z2 in the tire radial direction, so that the strain generated when the tire is deformed can be dispersed and the durability around the bead portion 11 can be dispersed. Can be improved.

(Change example 2)
In the above embodiment, almost the entire cord winding portion 23A2 of the up-ply 20A and the cord winding portion 23B2 of the down-ply 20B are provided in a wavy shape, but at least the outside of the bead filler 13 in the tire width direction of the cord winding portions 23A2 and 23B2. The portions located at Y2 may be provided in a wavy shape and intersect with each other.

Further, the cord winding portions 23A2 and 23B2 may be provided in a wavy shape over the entire bead filler 13, but the cord winding portions 23A2 and 23B2 are provided in a wavy shape in a region overlapping a part of the bead filler 13 in the tire radial direction Z. You may. When a wavy shape is provided in a part of the bead filler 13, it is preferable to provide the ply cords 23A and 23B in a wavy shape in the region from the tire radial outer side Z2 of the rim line 35 to the bead core 12 beyond the rim line 35.

Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention.

In order to specifically show the configuration and effect of the above embodiment, the tires of Comparative Examples and Examples 1 and 2 (tire size: 195 / 85R16 114L) were prototyped and their performance was evaluated. The evaluation method is as follows.
-Bead durability From the initial conditions of air pressure 600 KPa, reference load 11.6 KN, and speed 65 Km / h, the load was gradually increased and the test tire was run on a drum with a diameter of 1700 mm until the test tire failed. The mileage of the comparative example is set as 100 and described as an index. The larger the number, the better.

The tires of Comparative Examples and Examples 1 and 2 for which the performance was evaluated have the same structure as the tire 10 of FIG. 1 except for the shape of the ply cord provided in the winding portion of the two carcass plies.

Specifically, a comparative example is a tire in which the ply cords provided in the winding portion of the up ply and the winding laminated portion of the down ply extend linearly along the tire radial direction.

In the first embodiment, the ply cords provided in the winding portion of the up ply and the winding laminated portion of the down ply have a wavy shape and intersect each other in the tire side view, and the wavy shape is in the tire radial direction. It is a tire that does not change with.

In the second embodiment, the ply cords provided in the winding portion of the up ply and the winding laminated portion of the down ply have a wavy shape and intersect with each other in the side view of the tire, and the tire is outward in the radial direction. , A tire with a long wave-shaped wavelength and a small wave-shaped amplitude.

In each prototype tire, the distance between the tire circumferential directions R of the ply cords provided on the two carcass plies, the wave-shaped wavelength and amplitude formed in the cord winding portion, and the cord winding portions of the upply and downply. The phase difference of the formed wave shape is as shown in Table 1.

結果は表１に示す通りである。実施例１〜２では、比較例に比べてビード耐久性が向上した。コード巻き上げ部に形成された波形状の波長及び振幅をタイヤ径方向で変化させた実施例２ではビード耐久性がより一層向上した。

The results are shown in Table 1. In Examples 1 and 2, the bead durability was improved as compared with the comparative example. In Example 2 in which the wavelength and amplitude of the wave shape formed in the cord winding portion were changed in the tire radial direction, the bead durability was further improved.

10 ... tire, 11 ... bead part, 12 ... bead core, 13 ... bead filler, 14 ... sidewall part, 16 ... tread part, 20A ... up ply, 20B ... down ply, 21A ... main body part, 21B ... main body laminated part, 22A ... Winding part, 22B ... Winding stacking part, 22AE ... Winding end, 23A ... Ply cord, 23B ... Ply cord, 23A1 ... Cord body part, 23B1 ... Cord body part, 23A2 ... Cord winding part, 23B2 ... Cord winding part, 24A ... coated rubber, 24B ... coated rubber, 33 ... sidewall rubber, 34 ... inner liner, 35 ... rim line, 40 ... rim strip

Claims (4)

A pair of bead portions having a bead core and a bead filler arranged on the outer side of the bead core in the tire radial direction.
A main body portion provided between the pair of the bead portions, and a winding extending from the main body portion, being folded back from the inside to the outside in the tire width direction around the bead core, and being wound outward in the tire radial direction along the bead filler. Upply with a part and
In a pneumatic tire provided on the outer surface side of the tire of the up-ply and provided with a down-ply having a winding laminated portion overlapping the winding portion.
The up ply and the down ply include a ply cord arranged in a direction orthogonal to the tire circumferential direction and a coated rubber covering the ply cord.
The ply cords of the winding portion and the winding laminated portion are provided in a wave shape in which a portion of the bead filler located outside in the tire width direction extends in the tire radial direction with an amplitude in the tire circumferential direction. A pneumatic tire in which the winding portion and the winding laminated portion are overlapped so that the portions intersect with each other in the side view of the tire. The pneumatic tire according to claim 1, wherein the winding portion and the winding laminated portion are overlapped with each other by shifting the phase of the portions provided in the wavy shape. The pneumatic tire according to claim 1 or 2, wherein the wavy shape provided on the ply cord of the winding portion has a longer wavelength toward the outer side in the tire radial direction. The pneumatic tire according to any one of claims 1 to 3, wherein the wavy shape provided on the ply cord of the winding portion has an amplitude smaller toward the outside in the tire radial direction.

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