JP6686816B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire in which a belt layer is embedded in a tread portion, and more specifically, while effectively reducing rolling resistance, it is possible to effectively suppress uneven wear in a shoulder region and a center region of the tread portion. Regarding pneumatic tires made possible.

  A pneumatic tire is generally a carcass layer mounted between a pair of bead portions, a plurality of belt layers arranged on the tire radial direction outer side of the carcass layer in the tread portion, and a tire radial direction outer side of the belt layer. At least one belt reinforcing layer disposed so as to cover the belt layer, the belt layer includes a plurality of belt cords inclined with respect to the tire circumferential direction, and the belt cords intersect each other between the layers. It has a structure arranged like this.

  In recent years, for pneumatic tires for passenger cars, there is a strong demand to reduce rolling resistance, and in order to meet such requirements, design the tire so that the ground contact shape of the tread portion is generally rectangular. Is being done. However, as a demerit when the rectangular ground contact shape is adopted, uneven wear tends to easily occur in the shoulder region of the tread portion. On the other hand, in order to suppress uneven wear in the shoulder region, the inclination angle of the belt cord forming the belt layer with respect to the tire circumferential direction is made different depending on the position in the tire width direction, so that the end portion of the belt layer is It has been proposed to increase the rigidity in the tire circumferential direction (see, for example, Patent Document 1).

  However, when the rigidity in the tire circumferential direction at the end portion of the belt layer is increased based on the structure of the belt layer, the contact length in the center area of the tread portion is relatively increased, and uneven wear occurs in the center area of the tread portion. However, there is a problem that the rolling resistance is apt to occur, and the rolling resistance is deteriorated. Therefore, it is difficult to achieve both reduction of rolling resistance and suppression of uneven wear in the shoulder region and the center region of the tread portion.

JP, 2011-230538, A

  An object of the present invention is to provide a pneumatic tire capable of effectively suppressing uneven wear in the shoulder region and the center region of the tread portion while reducing rolling resistance.

The pneumatic tire of the present invention for achieving the above objects, a carcass layer mounted between a pair of bead portions, a plurality of belt layers arranged on the tire radial outside of the carcass layer in the tread portion, At least one belt reinforcing layer arranged so as to cover the belt layer on the tire radial direction outer side of the belt layer, the belt layer includes a plurality of belt cords inclined with respect to the tire circumferential direction, In a pneumatic tire arranged such that belt cords cross each other between layers,
In the belt layer, the inclination angle α of the belt cord with respect to the tire circumferential direction at the tire center position and the inclination angle β of the belt cord with respect to the tire circumferential direction at the belt end position are in a relationship of 15 ° ≦ β <α ≦ 35 °. Satisfied,
The belt reinforcing layer is set so that the rigidity in the tire circumferential direction per unit width is higher in the inner region than in the outer region in the tire width direction,
When the pneumatic tire is filled with an air pressure of 240 kPa and the tire is grounded under the condition that a load of 75% of the maximum load capacity defined by the standard is applied, the maximum contact length in the tire circumferential direction is L1, and the tire width direction is The maximum contact width of the tire is W1 and the contact length in the tire circumferential direction at a position of 40% of the maximum contact width W1 from the tire center position to the outer side in the tire width direction is L2, the maximum contact length L1 and the contact length L2. Satisfies the relationship of 0.8 ≦ L2 / L1 ≦ 1.0 , and
The belt layer has a high angle area on the center side where the inclination angle of the belt cord is in the range of α ± 1 ° and a low angle area on the shoulder side where the inclination angle of the belt cord is in the range of β ± 1 °. The width of the high angle region is 1/2 or more of the total width of the belt layer, and the width of the low angle region is 1/8 or more of the total width of the belt layer,
Alternatively, in the belt reinforcing layer, the inclination angle of the band cord with respect to the tire circumferential direction is in the range of 0 ° to 30 °, and the inclination angle of the band cord with respect to the tire circumferential direction gradually increases from the inner side to the outer side in the tire width direction. It is characterized by doing .

  In the present invention, in the belt layer, by adopting a structure in which the inclination angle β at the belt end position of the belt cord is smaller than the inclination angle α at the tire center position of the belt cord, the shoulder region of the tread portion Uneven wear can be suppressed. On the other hand, the rigidity in the tire circumferential direction per unit width of the belt reinforcing layer is relatively increased in the tire width direction inner region, and based on the ratio L2 / L1 of the maximum ground contact length L1 and the ground contact length L2 in the shoulder region. By making the ground contact shape specified by the substantially rectangular shape, it is possible to suppress uneven wear in the center region of the tread portion and avoid deterioration of rolling resistance. As a result, it is possible to effectively suppress uneven wear in the shoulder region and the center region of the tread portion while reducing the rolling resistance.

  In the present invention, the difference between the inclination angle α and the inclination angle β is preferably 3 ° or more. Thereby, the effect of suppressing uneven wear in the shoulder region of the tread portion can be sufficiently exerted.

  The belt layer has a high angle area on the center side where the inclination angle of the belt cord is in the range of α ± 1 ° and a low angle area on the shoulder side where the inclination angle of the belt cord is in the range of β ± 1 °. It is preferable that the width of the angle region is ½ or more of the total width of the belt layer, and the width of the low angle region is ⅛ or more of the total width of the belt layer. By setting the high-angle area on the center side and the low-angle area on the shoulder side of the belt layer as described above, the rigidity distribution of the tread portion can be optimized. The belt layer may have a connecting region between the high angle region and the low angle region, which allows the angle change of the belt cord.

  In the present invention, the belt reinforcing layer is set so that the rigidity in the tire circumferential direction per unit width is higher in the inner region than in the outer region in the tire width direction, and as a specific means thereof, it will be described below. It is preferred to employ at least one of the structures. That is, in the belt reinforcing layer, it is preferable that the belt cords are arranged such that the number of band cords to be driven per unit width is larger in the inner region than in the outer region in the tire width direction. Further, in the belt reinforcing layer, it is preferable that a band cord having higher rigidity than the band cord arranged in the outer region in the tire width direction is arranged in the inner region. Further, in the belt reinforcing layer, the inclination angle of the band cord with respect to the tire circumferential direction is in the range of 0 ° to 30 °, and the inclination angle of the band cord with respect to the tire circumferential direction gradually increases from the inner side to the outer side in the tire width direction. Preferably. By adopting these structures, the rigidity in the tire circumferential direction per unit width of the belt reinforcing layer can be adjusted.

  The pneumatic tire of the present invention is preferably a passenger car tire having an aspect ratio of 65% or less. According to the present invention, it is possible to effectively reduce uneven wear in the shoulder region and the center region of the tread portion while enabling reduction of rolling resistance required in a passenger vehicle tire.

  In the present invention, the ground contact shape of the tread portion is measured under the condition that the tire is assembled on a regular rim and is placed vertically on a plane with a predetermined air pressure filled and a predetermined load is applied. The “regular rim” is a rim that is defined for each tire in a standard system including a standard on which the tire is based. For example, JATMA is a standard rim, TRA is “Design Rim”, or ETRTO. If so, it is set to “Measuring Rim”. The air pressure is 240 kPa. Further, the predetermined load is 75% of the maximum load capacity defined for each tire by each standard in the standard system including the standard on which the tire is based.

It is a meridian sectional view showing the pneumatic tire which consists of an embodiment of the present invention. It is a development view showing a tread pattern of a pneumatic tire according to an embodiment of the present invention. 1 is a development view showing a belt layer of a pneumatic tire according to an embodiment of the present invention. It is a development view showing a modification of a belt layer in a pneumatic tire of the present invention. 1 is a plan view showing a ground contact shape of a pneumatic tire according to an embodiment of the present invention. It is a development view showing a belt reinforcement layer of a pneumatic tire consisting of an embodiment of the present invention. It is a development view showing a modification of a belt reinforcement layer in a pneumatic tire of the present invention. It is a development view showing other modifications of a belt reinforcement layer in a pneumatic tire of the present invention. It is a development view showing further another modification of the belt reinforcement layer in the pneumatic tire of the present invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show a pneumatic tire according to an embodiment of the present invention. 1 to 3, CL is the tire center position, Tc is the tire circumferential direction, and Tw is the tire width direction.

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

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of carcass cords extending in the tire radial direction, and is folded back from the tire inner side to the outer side around the bead core 5 arranged in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is arranged on the outer periphery of the bead core 5.

  On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of belt cords that are inclined with respect to the tire circumferential direction, and the belt cords are arranged so as to intersect each other between the layers. A steel cord is preferably used as the belt cord forming the belt layer 7. At least one belt reinforcing layer 8 including a plurality of band cords oriented in the tire circumferential direction is arranged on the outer peripheral side of the belt layer 7. It is desirable that the belt reinforcing layer 8 has a jointless structure in which a strip material in which at least one band cord is aligned and covered with rubber is continuously wound in the tire circumferential direction. As the band cord forming the belt reinforcing layer 8, an organic fiber cord such as nylon or aramid is preferably used.

  As shown in FIG. 2, the tread portion 1 is formed with a plurality of main grooves 10 extending in the tire circumferential direction. The main groove 10 includes at least one center main groove 11 and a pair of shoulder main grooves 12, 12 located outside the center main groove 11. A plurality of land portions 20 are defined in the tread portion 1 by these main grooves 10. The land portion 20 includes a center land portion 21 located between the pair of shoulder main grooves 12, 12 and a shoulder land portion 22 located outside each shoulder main groove 12. Each of the center land portions 21 is formed with a plurality of closing grooves 13 having one end opening to the shoulder main groove 12 and the other end terminating inside the center land portion 21. Further, in each shoulder land portion 22, a plurality of lug grooves 14 extending in the tire width direction and not communicating with the shoulder main groove 12 and a plurality of lug grooves 14 extending in the tire width direction are formed in the shoulder main groove 12. A plurality of sipes 15 communicating with each other are alternately formed along the tire circumferential direction.

  In the above pneumatic tire, as shown in FIG. 3, in at least one of the belt layers 7, and more preferably in both, the inclination angle α of the belt cord C at the tire center position CL with respect to the tire circumferential direction and the belt cord C. The inclination angle β with respect to the tire circumferential direction at the belt end position BE satisfies the relationship of 15 ° ≦ β <α ≦ 35 °.

  By adopting such a structure that the inclination angle β of the belt cord C at the belt end position BE is smaller than the inclination angle α of the belt cord C at the tire center position CL, the tire at the end portion of the belt layer 7 is The rigidity in the circumferential direction can be increased and uneven wear in the shoulder region of the tread portion 1 can be suppressed. In particular, by setting the difference between the inclination angle α and the inclination angle β to be 3 ° or more, it is possible to sufficiently exert the effect of suppressing uneven wear in the shoulder region of the tread portion 1. Here, when the inclination angle β is smaller than 15 °, the rigidity in the tire circumferential direction in the shoulder region of the tread portion 1 becomes excessive, and when the inclination angle α is larger than 35 °, the center region of the tread portion 1 becomes larger. Since the rigidity in the tire circumferential direction is excessively reduced, the contact length in the center region becomes too large.

  Further, as shown in FIG. 3, the belt layer 7 has a high angle region Ac on the center side where the inclination angle of the belt cord C is in the range of α ± 1 ° and the inclination angle of the belt cord C is in the range of β ± 1 °. And the width Lc of the high angle area Ac is 1/2 or more of the total width L of the belt layer 7, and the width Ls of each low angle area As is the total width L of the belt layer 7. It is good to be 1/8 or more. By setting the high-angle area Ac on the center side and the low-angle area As on the shoulder side of the belt layer 7 as described above, the rigidity distribution of the tread portion can be optimized. Here, if the width Lc of the high-angle region Ac is smaller than 1/2 of the total width L of the belt layer 7, the function as the belt layer 7 deteriorates, and the width Ls of the low-angle region As decreases the total width of the belt layer 7. If it is smaller than 1/8 of L, the rigidity in the tire circumferential direction in the shoulder region of the tread portion 1 cannot be sufficiently increased. The width Lc of the high angle region Ac and the width Ls of the low angle region As are set based on the total width L of each belt layer 7.

  FIG. 4 shows a modified example of the belt layer in the pneumatic tire of the present invention. In FIG. 4, the belt layer 7 has a connecting region Ax between the high angle region Ac on the center side and the low angle region As on the shoulder side, which allows the angle change of the belt cord C. By providing the connecting area Ax between the high angle area Ac and the low angle area As in this way, it is possible to allow a rapid angle change of the belt cord C.

  As described above, the width Lc of the high angle region Ac is 1/2 or more of the total width L of the belt layer 7, and the width Ls of each low angle region As is 1/8 or more of the total width L of the belt layer 7. The width Lx of each connecting region Ax inserted between the high angle region Ac and the low angle region As is 1/8 or less of the total width L of the belt layer 7. Further, the inclination angle γ of the belt cord C in the joining region Ax with respect to the tire circumferential direction satisfies the relationship of β <γ <α with respect to the inclination angles α and β.

  FIG. 5 shows a ground contact shape of the pneumatic tire according to the embodiment of the present invention. The pneumatic tire described above was filled with an air pressure of 240 kPa, and the maximum contact length in the tire circumferential direction when the tire was grounded under the condition that a load of 75% of the maximum load capacity defined by the standard was applied was set to L1 and the tire width When the maximum contact width in the direction is W1 and the contact length in the tire circumferential direction at the position of 40% of the maximum contact width W1 from the tire center position to the outside in the tire width direction is L2, the pneumatic tire has the maximum contact length. L1 and the ground length L2 are configured to satisfy the relationship of 0.8 ≦ L2 / L1 ≦ 1.0, and more preferably the relationship of 0.85 ≦ L2 / L1 ≦ 0.95.

  In this way, by making the ground contact shape specified based on the ratio L2 / L1 of the maximum ground contact length L1 and the ground contact length L2 in the shoulder area substantially rectangular, uneven wear in the center area of the tread portion 1 is suppressed. At the same time, deterioration of rolling resistance can be avoided. As a result, it is possible to effectively suppress uneven wear in the shoulder region and the center region of the tread portion 1 while reducing rolling resistance. Here, if the ratio L2 / L1 is smaller than 0.8, uneven wear in the center region of the tread portion 1 cannot be sufficiently suppressed, and further rolling resistance is deteriorated. Conversely, uneven wear is likely to occur in the shoulder region of the tread portion 1 where the ratio L2 / L1 is larger than 1.0.

In optimizing the ratio L2 / L1 (rectangular ratio) of the maximum ground contact length L1 and the ground contact length L2 as described above, in the pneumatic tire, the belt reinforcement layer 8 has a tire circumferential direction rigidity per unit width of the tire. It is set to be higher in the inner area than in the outer area in the width direction. That is, the cross-sectional area S (mm ² ) of the band cords constituting the belt reinforcing layer 8, the elastic modulus E (kN / mm ² ) of the band cords, and the number N of band cords per width 50 mm of the belt reinforcing layer 8 / 50 mm) and the inclination angle θ (°) of the band cord with respect to the tire circumferential direction is optimized so that the rigidity G (kN / 50 mm) in the tire circumferential direction per unit width of the belt reinforcing layer 8 is the position in the tire width direction. Has been adjusted accordingly. The rigidity G in the tire circumferential direction per unit width of the belt reinforcing layer 8 is calculated by, for example, G = S × E × N × cos ⁴ θ. The rigidity G per unit width of the belt reinforcing layer 8 is preferably in the range of 15 kN / 50 mm to 30 kN / 50 mm in the outer region in the tire width direction and higher than that in the inner region in the tire width direction.

  FIG. 6 shows a belt reinforcing layer of a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 6, when the belt reinforcing layer 8 is divided into an outer area Ao and an inner area Ai in the tire width direction, the number N of band cords B to be driven per unit width is in the inner area Ai than in the outer area Ao. It is set to be many. As a result, it is possible to suppress an excessive contact length in the center region of the tread portion 1 to optimize the contact shape, suppress uneven wear in the center region of the tread portion 1, and avoid deterioration of rolling resistance.

  FIG. 7 shows a modified example of the belt reinforcing layer in the pneumatic tire of the present invention. In FIG. 7, the belt reinforcing layer 8 has a jointless structure in which a strip material in which a plurality of band cords B are aligned and covered with rubber is continuously wound in the tire circumferential direction, and in the inner area Ai. The strip material is tightly wound so as to be adjacent to each other in each turn, and the strip material is loosely wound at intervals in each turn in the outer region Ao. For example, when the width of the strip material is 10 mm, the distance between the strip materials is set to 2 mm to 5 mm in the outer area Ao. As a result, the number N of the band cords B to be impressed per unit width of the belt reinforcing layer 8 is set to be larger in the inner area Ai than in the outer area Ao. As a result, it is possible to suppress an excessive contact length in the center region of the tread portion 1 to optimize the contact shape, suppress uneven wear in the center region of the tread portion 1, and avoid deterioration of rolling resistance.

  FIG. 8 shows a further modified example of the belt reinforcing layer in the pneumatic tire of the present invention. In FIG. 8, the band cords B constituting the belt reinforcing layer are arranged at equal intervals over the entire area. As the band cord B, two types of band cords Bi and Bo having different materials are used. That is, the band cord Bo is arranged in the outer region Ao of the belt reinforcing layer 8, the band cord Bi is arranged in the inner region Ai, and the tensile rigidity of the band cord Bi is higher than the tensile rigidity of the band cord Bo. ing. As a result, it is possible to suppress an excessive contact length in the center region of the tread portion 1 to optimize the contact shape, suppress uneven wear in the center region of the tread portion 1, and avoid deterioration of rolling resistance. For example, a hybrid cord of nylon and aramid is used as the band cord Bi of the inner region Ai, and a nylon cord is used as the band cord Bo of the outer region Ao. As the band cord B, it is also possible to adopt a tape-shaped synthetic resin sheet.

  In each of the above-described embodiments, it is desirable that the inner region Ai of the belt reinforcing layer 8 having relatively high rigidity be arranged so as to cover the high angle region Ac of the belt layer 7. When the belt layer 7 has a joining region Ax between the high-angle region Ac and the low-angle region As, the inner region Ai of the belt reinforcing layer 8 having relatively high rigidity corresponds to the joining region Ax of the belt layer 7. You may straddle it.

  FIG. 9 shows a further modified example of the belt reinforcing layer in the pneumatic tire of the present invention. As shown in FIG. 9, in the belt reinforcing layer 8, the inclination angle θ of the band cord B with respect to the tire circumferential direction is in the range of 0 ° to 30 °, and the inclination angle θ of the band cord B with respect to the tire circumferential direction is the tire width. It gradually increases from the inside to the outside in the direction. As a result, it is possible to suppress an excessive contact length in the center region of the tread portion 1 to optimize the contact shape, suppress uneven wear in the center region of the tread portion 1, and avoid deterioration of rolling resistance. Since the belt layer 7 has the low angle region As on the shoulder side, even if the rigidity of the belt cover layer 8 in the tire circumferential direction is slightly reduced in the region corresponding to that, the durability is not substantially affected. However, if the inclination angle θ of the band cord B with respect to the tire circumferential direction is larger than 30 °, the high-speed durability will be adversely affected.

  The pneumatic tire described above is suitable as a passenger car tire having an aspect ratio of 65% or less, and can reduce rolling resistance of the passenger car tire and improve uneven wear resistance.

  With a tire size of 205 / 55R16 91V, a carcass layer mounted between a pair of bead portions, two belt layers arranged on the tire radial direction outer side of the carcass layer in the tread portion, and a tire radial direction outer side of the belt layer. In a pneumatic tire including one belt reinforcing layer arranged in the above, a conventional example, a comparative example and an example in which the structure of the belt layer, the structure of the belt reinforcing layer, and the rectangular ratio of the ground contact shape are set as shown in Table 1. The tires of Examples 1 to 7 were manufactured.

  In the conventional example, a normal belt layer in which the inclination angle α of the belt cord with respect to the tire circumferential direction at the tire center position and the inclination angle β of the belt cord with respect to the tire circumferential direction at the belt end position are the same, and its belt layer A belt reinforcement layer (full cover) is used to cover the entire area.

  In the comparative example, the inclination angle β with respect to the tire circumferential direction at the belt end position of the belt cord is set smaller than the inclination angle α with respect to the tire circumferential direction at the tire center position of the belt cord, and the high angle region and the connecting region are set. A belt layer having a low angle region and a belt reinforcing layer (full cover) that covers the entire area of the belt layer were adopted.

  In Examples 1 to 7, the inclination angle β with respect to the tire circumferential direction at the belt end position of the belt cord is set to be smaller than the inclination angle α with respect to the tire circumferential direction at the tire center position of the belt cord, and a high angle region is set. A belt layer having a joining region and a low angle region and a belt reinforcing layer (FIGS. 6 to 9) covering the entire region of the belt layer were adopted.

  In Table 1, the boundary position between the high-angle region and the joint region, the boundary position between the joint region and the low-angle region, and the outer edge position of each belt layer are shown by the distance in the tire width direction from the tire center position. In addition, the rectangular ratio of the ground contact shape is the maximum ground contact in the tire circumferential direction when the pneumatic tire is filled with air pressure of 240 kPa and the ground is applied under the condition that a load of 75% of the maximum load capacity defined by the standard is applied. When the length is L1, the maximum contact width in the tire width direction is W1, and the contact length in the tire circumferential direction at a position 40% of the maximum contact width W1 from the tire center position to the outside in the tire width direction is L2, L2 / L1 × 100%.

  With respect to these test tires, uneven wear resistance (shoulder region, center region) and rolling resistance were evaluated by the following test methods, and the results are also shown in Table 1.

Uneven wear resistance (shoulder area, center area):
Each test tire was mounted on a wheel with a rim size of 16 × 6.5J and mounted on a friction energy measuring tester, and the average friction in the shoulder region and the center region of the tread portion under the conditions of an air pressure of 230 kPa and a load of 4.5 kN. Energy was measured. The measured value is obtained by measuring the frictional energy at a total of 4 points of 2 places in the tire width direction × 2 places in the tire circumferential direction at intervals of 10 mm in each region, and averaging these. The evaluation results are shown by using the reciprocal of the measured value, the uneven wear resistance in the shoulder region is shown by an index with the conventional example being 100, and the uneven wear resistance in the center region is shown by an index with the comparative example being 100. It was The larger the index value, the better the uneven wear resistance.

Rolling resistance:
Each test tire was mounted on a wheel having a rim size of 16 × 6.5J and mounted on a drum tester, and rolling resistance was measured according to ISO25280 under conditions of an air pressure of 210 kPa and a load load of 4.82 kN. The evaluation results are shown by indexes using the reciprocal of the measured value and setting the comparative example to 100. The larger the index value, the smaller the rolling resistance.

  As can be seen from Table 1, the tires of Examples 1 to 7 were excellent in uneven wear resistance in the shoulder region in comparison with the conventional example. In addition, the tires of Examples 1 to 7 were excellent in uneven wear resistance in the center region and were good in rolling resistance as compared with the comparative example.

1 Tread Part 2 Sidewall Part 3 Bead Part 4 Carcass Layer 5 Bead Core 6 Bead Filler 7 Belt Layer 8 Belt Reinforcing Layer 10 Main Groove 11 Center Main Groove 12 Shoulder Main Groove Ac High Angle Area of Belt Layer As Low Angle Area of Belt Layer Ax Belt layer connecting area Ai Belt reinforcing layer inner area Ao Belt reinforcing layer outer area B Band cord C Belt cord CL Tire center position BE Belt end position

Claims (7)

A carcass layer mounted between a pair of bead portions, a plurality of belt layers arranged outside the carcass layer in the tread portion in the tire radial direction, and covering the belt layer on the tire radial outside of the belt layer. And at least one belt reinforcing layer disposed in a plurality of belt cords, wherein the belt layer includes a plurality of belt cords inclined with respect to the tire circumferential direction, and the belt cords are arranged so that the belt cords cross each other. In the tire,
In the belt layer, the inclination angle α of the belt cord with respect to the tire circumferential direction at the tire center position and the inclination angle β of the belt cord with respect to the tire circumferential direction at the belt end position are in a relationship of 15 ° ≦ β <α ≦ 35 °. Satisfied,
The belt reinforcing layer is set so that the rigidity in the tire circumferential direction per unit width is higher in the inner region than in the outer region in the tire width direction,
The maximum contact length in the tire circumferential direction when the pneumatic tire was filled with an air pressure of 240 kPa and a load of 75% of the maximum load capacity defined by the standard was applied was set to L1 and the tire width direction The maximum contact width of the tire is W1 and the contact length in the tire circumferential direction at a position of 40% of the maximum contact width W1 from the tire center position to the outer side in the tire width direction is L2, the maximum contact length L1 and the contact length L2. Satisfies the relationship of 0.8 ≦ L2 / L1 ≦ 1.0 , and
The belt layer has a high angle area on the center side where the inclination angle of the belt cord is in the range of α ± 1 ° and a low angle area on the shoulder side where the inclination angle of the belt cord is in the range of β ± 1 °. The width of the high angle region is 1/2 or more of the total width of the belt layer, and the width of the low angle region is 1/8 or more of the total width of the belt layer . The pneumatic tire according to claim 1 , wherein the belt layer has a connecting region between the high angle region and the low angle region that allows an angle change of the belt cord. A carcass layer mounted between a pair of bead portions, a plurality of belt layers arranged outside the carcass layer in the tread portion in the tire radial direction, and covering the belt layer on the tire radial outside of the belt layer. And at least one belt reinforcing layer disposed in a plurality of belt cords, wherein the belt layer includes a plurality of belt cords inclined with respect to the tire circumferential direction, and the belt cords are arranged so that the belt cords cross each other. In the tire,
In the belt layer, the inclination angle α of the belt cord with respect to the tire circumferential direction at the tire center position and the inclination angle β of the belt cord with respect to the tire circumferential direction at the belt end position are in a relationship of 15 ° ≦ β <α ≦ 35 °. Satisfied,
The belt reinforcing layer is set so that the rigidity in the tire circumferential direction per unit width is higher in the inner region than in the outer region in the tire width direction,
The maximum contact length in the tire circumferential direction when the pneumatic tire was filled with an air pressure of 240 kPa and a load of 75% of the maximum load capacity defined by the standard was applied was set to L1 and the tire width direction The maximum contact width of the tire is W1 and the contact length in the tire circumferential direction at a position of 40% of the maximum contact width W1 from the tire center position to the outer side in the tire width direction is L2, the maximum contact length L1 and the contact length L2. Satisfies the relationship of 0.8 ≦ L2 / L1 ≦ 1.0, and
In the belt reinforcing layer, the inclination angle of the band cord with respect to the tire circumferential direction is in the range of 0 ° to 30 °, and the inclination angle of the band cord with respect to the tire circumferential direction gradually increases from the inner side to the outer side in the tire width direction. A pneumatic tire characterized by being The pneumatic tire according to claim 1, wherein the difference between the inclination angle β and the inclination angle α is 3 ° or more.   The belt reinforcing layer is arranged so that the number of band cords to be driven per unit width is larger in the inner region than in the outer region in the tire width direction. Pneumatic tire.   In the belt reinforcing layer, a band cord having higher rigidity than a band cord arranged in an outer region in the tire width direction is arranged in an inner region, and the air according to any one of claims 1 to 5. Included tires. The pneumatic tire according to any one of claims 1 to 6, characterized in that said pneumatic tire is a passenger tire of 65% or less aspect ratio.

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