JP2014227149A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve riding comfort and operation stability in a pneumatic tire while reducing rolling resistance by devising a reinforcement layer arranged on a tire side face part.SOLUTION: A pneumatic tire is provided with: a pair of bead parts 5 having a bead core 51 and a bead filler 52, and arranged on both sides in the tire width direction; a pair of sidewall parts 4 continuing to the pair bead parts 5; a tread part 2 for connecting the pair bead sidewall parts 4; a carcass layer 6 which is arranged in a tire radial direction inside in the tread part 2, and where an end part in the tire width direction is folded from a tire width direction inside to a tire width direction outside by the bead core 51; and a side reinforcement layer 9 formed of a multi-axis fabric weaved with a four-axis single wire cord 91, and arranged inside or outside in the tire width direction in the bead filler 52.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that improves rolling comfort and driving stability while reducing rolling resistance by devising a reinforcing layer that covers both ends of a sidewall portion and a bead portion in the tire width direction. It relates to tires.

  In a pneumatic tire, when the tire cross-section height is high, it is necessary to increase the rigidity of the sidewall portion. For this reason, a reinforcing layer is disposed on the sidewall portion or the bead portion. As a pneumatic tire constituted so that a reinforcing layer may be arranged in a side wall part or a bead part, there are some which were indicated in the following patent documents.

  Conventionally, in the pneumatic tire described in Patent Document 1, at least a part of the tire is composed of a triaxial or multiaxial fabric. In this pneumatic tire, specifically, in a tire having a carcass layer, a belt layer, and a belt reinforcing layer, it is desirable to use a multiaxial fabric for the carcass layer. In the pneumatic tire described in Patent Document 2, a reinforcing layer including a plurality of steel cords is embedded from the bead portion to the sidewall portion.

JP 2008-230334 A JP 2011-131680 A

  When the reinforcing layer is disposed on the sidewall portion or the bead portion, the circumferential rigidity of the sidewall portion does not increase so much because the flex zone is wide unless it is disposed up to a high position of the sidewall portion. Moreover, if the steel reinforcing layer made of a stranded wire is disposed up to a position where the tire cross-section height is high, the loss energy of the portion where the deformation of the tire is large is increased, and the rolling resistance is deteriorated. On the other hand, when a steel reinforcing layer composed of a single wire is formed, there is no friction between the cords compared to the stranded wire, so that although rolling resistance is reduced, the damping property is deteriorated and the riding comfort is deteriorated.

  The present invention solves the above-described problems, and provides a pneumatic tire that improves riding comfort and handling stability while reducing rolling resistance by devising a reinforcing layer disposed on a side surface of the tire. With the goal.

  In order to achieve the above object, a pneumatic tire according to the present invention includes a bead core and a bead filler, a pair of bead portions disposed on both sides in the tire width direction, and a pair of side portions continuous to the pair of bead portions. A wall portion, a tread portion connecting the pair of sidewall portions, and an inner end in the tire radial direction of the tread portion, and an end portion in the tire width direction is folded back from the inner side in the tire width direction to the outer side in the tire width direction by the bead core. A carcass layer, and a reinforcing layer which is formed of a multiaxial woven fabric in which at least triaxial single-wire cords are woven and is disposed on the inner side or the outer side in the tire width direction of the bead filler. is there.

  Therefore, by arranging a reinforcement layer formed of multiaxial woven fabric on the inner or outer side in the tire width direction of the bead filler, it is possible to reduce rolling resistance and effectively increase the circumferential rigidity of the tire side surface portion. Thus, ride comfort and handling stability can be improved.

  In the pneumatic tire according to the present invention, the single wire cord is constituted by a steel cord or a monofilament.

  Therefore, by forming a reinforcing layer with a multi-axis woven fabric of three or more single cords such as steel cords and monofilaments, the rolling resistance of the tires is reduced and the ride comfort and handling stability are improved. Can do.

  The pneumatic tire of the present invention is characterized by satisfying 0.35SH ≦ SRFH ≦ 0.55SH when the tire cross-sectional height SH is set and the reinforcing layer is disposed at a height SRFH.

  Accordingly, by setting the height of the reinforcing layer to an appropriate height with respect to the tire cross-section height, it is possible to achieve both improvement in the circumferential rigidity of the tire side surface portion and reduction in rolling resistance.

  The pneumatic tire of the present invention is characterized in that TUH−SRFH ≧ 10 mm is satisfied when the arrangement height TUH of the carcass layer is set and the arrangement height SRFH of the reinforcing layer is set.

  Therefore, by setting the placement height of the carcass layer and the placement height of the reinforcing layer to appropriate heights, the end height in the carcass layer and the end height in the reinforcement layer are shifted by a predetermined distance, and cracks due to stress concentration are generated. Can be prevented.

  In the pneumatic tire of the present invention, the single wire cord has an end number of 40 [lines / 50 mm] or more and 80 [lines / 50 mm] or less, and an average interval of 0.1 [mm] or more and 0.8 [lines]. mm] or less.

  Therefore, by defining the number of ends of the single wire cord and the average interval in an appropriate region, it is possible to suppress an increase in mass while suppressing a decrease in rigidity and durability.

  In the pneumatic tire according to the present invention, the single wire cord is provided with a spiral or plane wave brazing.

  Therefore, the reinforcing layer can be expanded and contracted by brazing, so that not only the rolling resistance of the tire can be reduced but also the ride comfort and the handling stability can be improved, and the durability can be improved.

  According to the pneumatic tire according to the present invention, since the reinforcing layer formed of the multiaxial woven fabric in which at least the triaxial single wire cords are woven is arranged on the inner side or the outer side in the tire width direction in the bead filler, the rolling resistance is reduced. In addition, it is possible to improve ride comfort and handling stability.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is an enlarged plan view of the steel cord of the side reinforcing layer. FIG. 3 is a schematic view showing the arrangement position of the side reinforcing layer. FIG. 4A is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 4B is a schematic diagram illustrating the arrangement position of the side reinforcing layer. FIG. 4-3 is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 4-4 is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 5A is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 5B is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 5C is a schematic diagram illustrating an arrangement position of the side reinforcing layer. FIG. 6 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

  FIG. 1 is a meridional sectional view of a pneumatic tire according to this embodiment. In the following description, as shown in FIG. 1, the tire radial direction means a direction orthogonal to the rotation axis (not shown) of the pneumatic tire 1, and the tire radial direction inner side means the rotation axis in the tire radial direction. The heading direction and the outer side in the tire radial direction refer to the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to a direction around the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction means the side toward the tire equator plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction means the tire width direction. Is the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotation axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line along the tire circumferential direction of the pneumatic tire 1 on the tire equator plane CL. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line.

  The pneumatic tire 1 of the present embodiment includes a tread portion 2, shoulder portions 3 on both sides thereof, and sidewall portions 4 and bead portions 5 that are continuous from the shoulder portions 3. The pneumatic tire 1 has a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8.

  The tread portion 2 is made of a rubber material (tread rubber), is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof is the contour of the pneumatic tire 1. A tread surface 21 is formed on the outer peripheral surface of the tread portion 2, that is, on the tread surface that contacts the road surface during traveling. The tread surface 21 is provided with a plurality of (two in this embodiment) main grooves 22 that are straight main grooves extending along the tire circumferential direction and parallel to the tire equator line CL. The tread surface 21 extends along the tire circumferential direction by the plurality of main grooves 22, and a plurality of rib-like land portions 23 parallel to the tire equator line CL are formed. Although not shown in the figure, the tread surface 21 is provided with a lug groove that intersects the main groove 22 in each land portion 23. The lug groove may be provided with both ends communicating with the main groove 22 such that the land portion 23 is divided into a plurality of portions in the tire circumferential direction, or the land portion 23 is communicated with the tire circumferential direction. May be provided to terminate in the middle of the land portion 23. Further, the lug groove is formed to open to the outer side in the tire width direction at the outermost land portion 23 in the tire width direction.

  The shoulder portion 3 is a portion on both outer sides in the tire width direction in the tread portion 2. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 52 is a rubber material disposed in a space formed by folding an end portion of the carcass layer 6 in the tire width direction at the position of the bead core 51.

  The carcass layer 6 has a multilayer structure in which at least two carcass 6A and 6B are stacked. The carcass layer 6 has both tire width direction ends extending from the tread portion 2 to each bead portion 5, and each tire width direction end portion is a pair of bead cores 51 from the tire width direction inner side to the tire width direction outer side. The tire skeleton is formed by being folded in a toroidal shape in the tire circumferential direction. The carcass layer 6 is formed by coating a plurality of carcass cords (not shown) arranged in parallel at an angle in the tire circumferential direction with an angle with respect to the tire circumferential direction being along the tire meridian direction. The carcass cord is made of organic fibers (polyester, rayon, nylon, etc.). In this case, one carcass 6 </ b> A is folded back from the inner side in the tire width direction of the bead 5 portion to the outer side in the tire width direction, and the end portion 6 </ b> Aa is disposed on the outer side in the tire width direction in the sidewall portion 4. The other carcass 6 </ b> B is folded back from the inner side in the tire width direction of the bead 5 part to the outer side in the tire width direction, and the end part 6 </ b> Ba is disposed on the outer side in the tire width direction in the bead filler 52. That is, each of the carcass 6A and 6B is disposed such that the end portions 6Aa and 6Ba are shifted in the tire radial direction.

  The belt layer 7 has a multilayer structure in which at least two belts 7A and 7B are laminated, and belt covers 7C and 7D are arranged on the outer sides in the tire circumferential direction of the two layers of belts 7A and 7B. The belt layer 7 is disposed on the outer side in the tire radial direction that is the outer periphery of the carcass layer 6 in the tread portion 2, and covers the carcass layer 6 in the tire circumferential direction. The belts 7A and 7B are made by coating a plurality of cords (not shown) arranged in parallel at a predetermined angle (for example, 20 [°] to 30 [°]) with a coat rubber with respect to the tire circumferential direction. . The cord is made of steel or organic fiber (polyester, rayon, nylon, etc.). Further, the overlapping belts 7A and 7B are arranged so that the cords intersect each other. The belt 7A on the inner side in the tire radial direction has a larger tire width direction dimension than the belt 7B on the outer side in the tire radial direction, and is disposed so as to protrude outward in the tire width direction from the end portion of the belt 7B in the tire width direction. . The dimension of the belt 7A in the tire width direction is the maximum width of the belt layer 7 in the tire width direction. The belt covers 7C and 7D are formed by rolling a plurality of belt cords made of steel or organic fiber material coated with a coat rubber, and are stacked on the outer side in the tire radial direction of the belts 7A and 7B.

  The belt reinforcing layer 8 is disposed by being wound around the outer side of the belt layer 7 in the tire radial direction, and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is a fiber cord covered with a coat rubber. The belt reinforcing layer 8 is disposed on each side in the tire width direction so as to cover ends of the belt layer 7 in the tire width direction. The configuration of the belt reinforcing layer 8 is not limited to the above, and is not clearly shown in the figure. For example, the belt reinforcing layer 8 includes two reinforcing layers that overlap in the tire radial direction, and each reinforcing layer is an end of the belt layer 7 in the tire width direction. May be arranged separately on both sides in the tire width direction so as to cover each. That is, the belt reinforcing layer 8 overlaps at least the end of the belt layer 7 in the tire width direction in the tire radial direction, and reinforces the vicinity of the end of the belt layer 7 in the tire width direction.

  In the present embodiment, a side reinforcing layer (reinforcing layer) 9 is disposed at least in the bead filler 52 in the tire width direction inside or in the tire width direction outside in the bead portion 5. The side reinforcing layer 9 is formed of a multiaxial fabric in which at least a triaxial single wire cord 91 (see FIG. 2) is woven. The single wire cord 91 is made of a steel cord or a monofilament.

  FIG. 2 is an enlarged plan view of the steel cord of the side reinforcing layer.

  In the pneumatic tire 1 described above, as shown in FIG. 2, the side reinforcing layer 9 includes a single wire cord 91 made of a four-axis fabric. The four-axis woven fabric has a longitudinal member 91a substantially 0 [°] (including ± 5 [°]) with respect to the tire circumferential direction and substantially 90 [°] (± 5 [within the tire circumferential direction). A cross member 91b) and 30 [°] or more and 60 [°] or less (preferably substantially 45 [°] (including ± 5 [°])) with respect to the tire circumferential direction. Two diagonal members 91c and 91d intersecting each other are woven. That is, in the four-axis fabric, the longitudinal members 91a and the transverse members 91b are alternately overlapped in the tire width direction in the tire circumferential direction and the tire radial direction, and one diagonal member 91c is in the tire width direction of the longitudinal members 91a and the transverse members 91b. A tire in which one side (for example, the inner side in the tire width direction) overlaps with the other diagonal member 91d on the other side in the tire width direction (for example, the outer side in the tire width direction), and the other diagonal member 91d is the vertical member 91a. It is woven so as to overlap the other side in the width direction (for example, the outer side in the tire width direction) and to overlap one side (for example, the inner side in the tire width direction) of the cross member 91b.

  FIG. 2 shows the side reinforcing layer 9 so that the woven shape is clear. In an actual arrangement state, the longitudinal members 91a are arranged in a ring shape along the tire circumferential direction on the tire side surface. The cross members 91b are arranged radially on the tire side surface along the tire radial direction, and the diagonal members 91c and 91d are arranged at a predetermined angle with respect to the vertical members 91a and the cross members 91b.

  In addition, the four-axis woven fabric is not limited to the above-described woven shape, and it is only necessary that the longitudinal members 91a, the transverse members 91b, and the diagonal members 91c and 91d are woven so as not to separate from each other. . The side reinforcing layer 9 is not limited to a four-axis woven fabric, and may be a triaxial woven fabric or a multiaxial woven fabric having five or more axes. However, when forming a multiaxial woven fabric, it is desirable to use the same type of single-wire cord among steel cords or monofilaments.

  Moreover, the side reinforcement layer 9 should just be arrange | positioned at the tire width direction inner side in the bead filler 52 or a tire width direction outer side. In other words, the bead core 51 and the bead filler 52 may be disposed on the inner side in the tire width direction or the outer side in the tire width direction.

  As shown in FIG. 1, the side reinforcing layer 9 has an inner end portion 9a in the tire radial direction disposed at an inner end in the tire radial direction of the bead filler 52 (a boundary position between the bead core 51 and the bead filler 52). The outer end portion 9 b is disposed on the sidewall portion 4. And when it is set as tire section height SH and arrangement height SRFH of side reinforcement layer 9, it is desirable to satisfy 0.35SH <= SRFH <= 0.55SH.

  Here, the tire cross-section height SH is the length in the tire radial direction from the lower end position (inner end in the tire radial direction) to the tire outer peripheral end position (tread surface 21) in the bead core 51 in a tire unloaded state. The tire cross-section height SH is also referred to as 1/2 of the difference between the tire outer diameter and the rim diameter. The arrangement height SRFH of the side reinforcing layer 9 is a tire radial direction length from the lower end position (inner end in the tire radial direction) of the bead core 51 to the outer end portion 9b of the side reinforcing layer 9 in a tire unloaded state. is there.

  When the arrangement height SRFH of the side reinforcing layer 9 is smaller than 0.35SH, the circumferential rigidity in the tire side surface portion is not sufficiently improved. Further, if the arrangement height SRFH of the side reinforcing layer 9 is larger than 0.55SH, the circumferential rigidity at the tire side surface portion becomes too high, and the rolling resistance is not sufficiently reduced.

  The side reinforcing layer 9 preferably satisfies TUH−SRFH ≧ 10 mm when the arrangement height TUH of the carcass layer 6 is set and the arrangement height SRFH of the side reinforcement layer 9 is set. Here, the arrangement height TUH of the carcass layer 6 is the tire radial direction length from the lower end position (inner end in the tire radial direction) of the bead core 51 to the end portion 6Aa of the carcass 6A in the tire unloaded state. The arrangement height TUH of the carcass layer 6 is also the length in the tire radial direction from the lower end position (inner end in the tire radial direction) of the bead core 51 to the end portion 6Ba of the carcass 6B in the tire unloaded state.

  If the positions of the end 6Aa of the carcass layer 6 and the outer end 9b of the side reinforcing layer 9 are smaller than 10 mm, side cracks are likely to occur due to stress concentration of the end wrap.

  The side reinforcing layer 9 has an end number of the single wire cord 91 of 40 [lines / 50 mm] to 80 [lines / 50 mm] and an average interval of 0.1 [mm] to 0.8 [mm]. It is desirable that If the number of ends of the single wire cord 91 is less than 40 [lines / 50 mm], the rigidity of the tire side surface portion is lowered. If the number of ends of the single wire cord 91 is more than 80 [lines / 50 mm], The thickness at the intersection of the material 91b and the diagonal materials 91c and 91d increases and the mass increases. Further, when the average interval of the single wire cords 91 is smaller than 0.1 [mm], the load durability is lowered, and when it is larger than 0.8 [mm], the rigidity does not increase.

  As for the side reinforcement layer 9, it is desirable for the single wire cord 91 to be braided in a spiral shape or a plane wave shape.

  Here, the arrangement of the side reinforcing layers 9 will be specifically described. 3 to 5-3 are schematic views illustrating specific arrangement positions of the side reinforcing layers. 3, the side reinforcing layer 9 </ b> A is arranged inside the bead part 5, and FIGS. 4A to 4-4 show the side reinforcing layers 9 </ b> B, 9 </ b> C, 9 </ b> D, 9 </ b> E outside the bead part 5 than the carcass layer 6. FIG. 5A to FIG. 5C are schematic views in which the side reinforcing layers 9F, 9G, and 9H are disposed outside the carcass layer 6.

  As shown in FIG. 3, the pneumatic tire includes a tread portion (2), a shoulder portion (3), a sidewall portion (4), and a bead portion 5, as in the first embodiment (FIG. 1). It has a carcass layer 6, a belt layer (7), and a belt reinforcing layer (8). The carcass layer 6 has a structure in which two layers of carcass 6A and 6B are laminated, and the end portions 6Aa and 6Ba are arranged so as to be shifted in the tire radial direction. The side reinforcing layer 9A is disposed inside the bead filler 52 in the bead portion 5 and outside the carcass layer 6 (carcass 6A, 6B), that is, between the bead filler 52 and the carcass 6B.

  As shown in FIG. 4A, this pneumatic tire has a tread portion (2), a shoulder portion (3), a sidewall portion (4), and a bead portion as in the first embodiment (FIG. 1). 5, a carcass layer 6, a belt layer (7), and a belt reinforcing layer (8), but the carcass layer 6 has a structure constituted by a single carcass, and an end portion 6 a is a side wall portion (4). Is arranged. The side reinforcing layer 9B is disposed outside the bead filler 52 in the bead portion 5 and inside the folded carcass layer 6, that is, between the bead filler 52 and the folded carcass layer 6.

  As shown in FIG. 4B, this pneumatic tire has the same configuration as that of the first embodiment (FIG. 1) described above, and the side reinforcing layer 9C is outside the bead filler 52 in the bead portion 5, and It is arranged inside the folded carcass layer 6, that is, between the bead filler 52 and the folded carcass 6B.

  As shown in FIG. 4-3, although this pneumatic tire has the same configuration as that of the first embodiment (FIG. 1), the carcass layer 6 has one carcass 6A in the tire width direction of the bead portion 5. Folded from the inside to the outside in the tire width direction, the end portion 6Aa is disposed on the sidewall portion (4), the other carcass 6C is folded from the outside in the tire width direction of the bead portion 5 to the inside in the tire width direction, and the end portion 6Ca is The bead core 51 is disposed on the inner side in the tire radial direction. The side reinforcing layer 9D is disposed outside the bead filler 52 in the bead part 5 and inside the carcass layer 6, that is, between the folded carcass 6A and 6C.

  As shown in FIG. 4-4, the pneumatic tire has the same configuration as that of the first embodiment (FIG. 1) described above, and the side reinforcing layer 9E is outside the bead filler 52 in the bead portion 5, and It is disposed inside the carcass layer 6, that is, between the folded carcass 6A and carcass 6B. The side reinforcing layer 9 </ b> E has an end portion on the inner side in the tire radial direction that extends from the bead filler 52 to the bead core 51 and is folded back by the bead core 51.

  As shown in FIG. 5A, the pneumatic tire has the same configuration as that of the first embodiment (FIG. 1) described above, but the carcass layer 6 has a structure constituted by a single layer of carcass. The part 6a is arranged on the sidewall part (4). The side reinforcing layer 9 </ b> F is disposed outside the bead filler 52 in the bead portion 5 and outside the folded carcass layer 6.

  As shown in FIG. 5-2, this pneumatic tire has the same configuration as that of the first embodiment (FIG. 1) described above, and the side reinforcing layer 9G is outside the bead filler 52 in the bead portion 5, and It is arranged outside the folded carcass layer 6.

  As shown in FIG. 5-3, the pneumatic tire has the same configuration as that of the first embodiment (FIG. 1), but the carcass layer 6 has one carcass 6A in the tire width direction of the bead portion 5. Folded from the inside to the outside in the tire width direction, the end portion 6Aa is disposed on the sidewall portion (4), the other carcass 6C is folded from the outside in the tire width direction of the bead portion 5 to the inside in the tire width direction, and the end portion 6Ca is The bead core 51 is disposed on the inner side in the tire radial direction. The side reinforcing layer 9 </ b> H is disposed outside the bead filler 52 in the bead portion 5 and outside the carcass layer 6.

  As described above, in the pneumatic tire 1 according to the present embodiment, the pair of bead portions 5 that have the bead core 51 and the bead filler 52 and are arranged on both sides in the tire width direction, and the pair of bead portions 5 are continuous. A pair of sidewall portions 4, a tread portion 2 that connects the pair of sidewall portions 4, and a tire core in the tire tread portion 2 that is disposed on the inner side in the tire radial direction and has a bead core 51 at the end in the tire width direction. A carcass layer 6 that is folded outward in the width direction and a side reinforcing layer 9 that is formed of a multiaxial woven fabric in which four-axis single-wire cords 91 are woven and are disposed on the inner side or the outer side in the tire width direction of the bead filler 52 are provided. ing.

  Therefore, by arranging the side reinforcing layer 9 formed of multiaxial woven fabric on the inner side or the outer side in the tire width direction in the bead filler 52, the tire rolling resistance can be reduced and the circumferential rigidity of the tire side surface portion can be reduced. Riding comfort and handling stability can be improved by effectively raising.

  In the pneumatic tire 1 of the present embodiment, the single wire cord 91 is made of a steel cord or a monofilament. Therefore, by forming a reinforcing layer with a multi-axis woven fabric of three or more single-wire cords 91 such as steel cords and monofilaments, the rolling resistance of the tire is reduced and the ride comfort and the handling stability are improved. be able to.

  In the pneumatic tire 1 of the present embodiment, when the tire cross-sectional height SH is set and the side reinforcing layer 9 is disposed at a height SRFH, 0.35SH ≦ SRFH ≦ 0.55SH is satisfied. By setting the arrangement height of the side reinforcing layer 9 to an appropriate height with respect to the tire cross-section height, it is possible to achieve both improvement in the circumferential rigidity of the tire side surface portion and reduction in rolling resistance.

  In the pneumatic tire 1 of the present embodiment, when the arrangement height TUH of the carcass layer 6 is set and the arrangement height SRFH of the side reinforcing layer 9 is set, TUH−SRFH ≧ 10 mm is satisfied. Therefore, the height of the end portions 6Aa and 6Ba in the carcass layer 6 and the height of the inner end portion 9a in the side reinforcing layer 9 are set by appropriately setting the arrangement height of the carcass layer 6 and the arrangement height of the side reinforcing layer 9. It will shift | deviate more than predetermined distance and generation | occurrence | production of the crack by stress concentration can be prevented.

  In the pneumatic tire 1 of the present embodiment, the number of ends of the single wire cord 91 is 40 [lines / 50 mm] or more and 80 [lines / 50 mm] or less, and the average interval is 0.1 [mm] or more and 0.8. [Mm] or less. Therefore, by defining the number of ends and the average interval of the single wire cord 91 in an appropriate region, it is possible to suppress an increase in mass while suppressing a decrease in rigidity and durability.

  In the pneumatic tire 1 of the present embodiment, the single wire cord 91 is brazed in a spiral shape or a plane wave shape. Therefore, the side reinforcing layer 9 can be expanded and contracted by brazing, and not only can the ride resistance and steering stability be improved while reducing the rolling resistance of the tire, but also the durability can be improved.

  FIG. 6 is a chart showing the results of the performance test of the pneumatic tire according to this example. In this example, performance tests on rolling resistance, steering stability, and ride comfort damping performance were performed on multiple types of pneumatic tires with different conditions.

  In this performance test, a pneumatic tire (air pressure 230 [kPa]) having a tire size of 225 / 65R17 was used as a test tire.

  In addition, the pneumatic tire is evaluated by a test tire that is assembled on a regular rim and filled with a regular internal pressure (230 [kPa]). A test vehicle (displacement 2400cc, front wheel drive (front engine / front drive) system, multipurpose for sports) (Sports, utility vehicle) car).

  Here, the regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO.

  The rolling resistance was evaluated by a method in which the test tire was assembled on a regular rim and filled with an air pressure of 230 [kPa], and the steel tire rolling resistance tester was used at a speed of 80 [km / h] for 20 [ The rolling resistance after a preliminary run of minutes] is measured. Then, based on the measurement result, index evaluation using the conventional example as a reference (100) is performed. This index evaluation indicates that the larger the value, the lower the rolling resistance and the better.

  Steering stability is evaluated with this test vehicle at a speed of 60 [km / h] to 120 [km / h], straight running stability during straight running, turning stability during lane change and cornering, rigidity, steering The sex item was evaluated by sensory evaluation by a skilled driver. Then, based on this sensory evaluation, index evaluation using the conventional example as a reference (100) is performed. This evaluation shows that the larger the index, the better the steering stability.

  Riding comfort attenuation is evaluated by performing actual vehicle running on good roads, joint roads and bad roads at speeds of 40 [km / h] to 80 [km / h] with the above test vehicle, and sensory evaluation (driving) by a skilled driver Riding comfort was evaluated by vibration evaluation. Then, based on this sensory evaluation, index evaluation using the conventional example as a reference (100) is performed. This evaluation shows that an index of 90 or more maintains riding comfort as an acceptable range (however, it is preferable to arrange the index to be 99 to 100).

  As shown in FIG. 6, a performance test was performed on the pneumatic tires of the conventional example, comparative example 1, comparative example 2, and examples 1 to 4. In the pneumatic tire of the conventional example, the reinforcing cord is a stranded wire, the woven structure is uniaxial, the entire fabric range, the angle of the diagonal material is 30 °, and the arrangement position (SRFH / SH) is 30%. The pneumatic tire of Comparative Example 1 has the same reinforcing cord as that of the conventional example, the woven structure, the woven fabric range, the angle of the diagonal material, and the arrangement position. Further, in the pneumatic tire of Comparative Example 2, the reinforcing cord is a stranded wire, the woven structure is triaxial, the entire woven range, the oblique material angle is 60 degrees, the transverse material angle is 90 degrees, the arrangement position (SRFH / SH ) Is 30%.

  On the other hand, in the pneumatic tire of Example 1, the reinforcing cord is a single wire, the woven structure is triaxial, the entire woven range, the oblique material angle is 60 degrees, the transverse material angle is 90 degrees, and the arrangement position (SRFH / SH) Is 30%. In the pneumatic tire of Example 2, the reinforcing cord is a single wire, the weaving structure is four axes, the entire woven range, the oblique material angle is 60 degrees, the longitudinal material angle is 0 degree, and the transverse material angle is 90 degrees. The position (SRFH / SH) is 30%. In the pneumatic tire of Example 3, the reinforcing cord is a single wire, the woven structure is four axes, the entire woven range, the diagonal material angle is 60 degrees, the vertical material angle is 0 degree, and the horizontal material angle is 90 degrees. The position (SRFH / SH) is 35%. In the pneumatic tire of Example 4, the reinforcing cord is a single wire, the weaving structure is 4 axes, the entire woven range, the diagonal material angle is 60 degrees, the longitudinal material angle is 0 degree, and the transverse material angle is 90 degrees. The position (SRFH / SH) is 45%.

  As shown in the test results of FIG. 6, it can be seen that the pneumatic tires of Examples 1 to 4 have improved rolling resistance, steering stability, and riding comfort damping.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Shoulder part 4 Side wall part 5 Bead part 6 Carcass layer 7 Belt layer 8 Belt reinforcement layer 9, 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H Side reinforcement layer (reinforcement layer )
51 Bead core 52 Bead filler 91 Single wire cord 91a Vertical material 91b Horizontal material 91c, 91d Diagonal material

Claims (6)

A pair of bead portions having bead cores and bead fillers and disposed on both sides in the tire width direction;
A pair of sidewall portions continuous to the pair of bead portions;
A tread portion connecting the pair of sidewall portions;
A carcass layer that is disposed on the inner side in the tire radial direction of the tread portion and an end portion in the tire width direction is folded back from the inner side in the tire width direction to the outer side in the tire width direction at the bead core;
A reinforcement layer formed of a multiaxial woven fabric in which at least triaxial single-wire cords are woven, and disposed inside or outside in the tire width direction of the bead filler;
A pneumatic tire characterized by comprising:   The pneumatic tire according to claim 1, wherein the single wire cord is formed of a steel cord or a monofilament.   The pneumatic tire according to claim 1 or 2, wherein when the tire cross-sectional height SH is set and the reinforcing layer arrangement height SRFH is satisfied, 0.35SH≤SRFH≤0.55SH is satisfied.   4. The air according to claim 1, wherein TUH−SRFH ≧ 10 mm is satisfied when the arrangement height of the carcass layer is TUH and the arrangement height of the reinforcing layer is SRFH. 5. Enter tire.   The single wire cord has an end number of 40 [lines / 50 mm] to 80 [lines / 50 mm] and an average interval of 0.1 [mm] to 0.8 [mm]. The pneumatic tire according to any one of claims 1 to 4.   The pneumatic tire according to any one of claims 1 to 5, wherein the single wire cord is provided with a spiral or plane wave brazing.

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