JP2018095135A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire maintaining comfortable ride quality and weight saving, and exerting high sidewall rigidity.SOLUTION: In an objective pneumatic tire, a carcass 4 includes a folding ply 7 folded from inside toward outside in a tire axial direction on the periphery of each bead core 6, and a non-folding ply 8 terminating in front of the bead core without folding on the periphery of the bead core. The folding ply has the main body parts 7Aa, 7Ba extending between the bead cores in a toroidal shape, and a pair of folding parts folded on the periphery of the bead core. The bead part 3 includes a first apex 11 passing through between the main body part of the folding ply and the folding part to extend outside in a tire radial direction in a tapered shape, and a second apex 12 contacting outside the folding part 7Bb of the folding ply and extending outside in the tire radial direction in the tapered shape. The outer end of the first apex in the tire radial direction is located inside the outer end of the second apex in the tire radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can be suitably applied to a small truck.

  Pneumatic tires for small trucks used mainly for vans and small trucks used for transporting luggage require high sidewall rigidity to support a large load. On the other hand, high sidewall rigidity tends to impair riding comfort and excessively increase tire weight.

JP 2014-004844 A JP 2013-169817 A

  The present invention has been devised in view of the above-described problems, and has as its main object to provide a pneumatic tire that can exhibit high sidewall rigidity while maintaining ride comfort and weight reduction.

  The present invention is a pneumatic tire comprising a tread portion, a pair of bead portions each having a bead core embedded therein, and a carcass having a carcass cord straddling between the pair of bead portions, A folded ply folded around each bead core from the inner side to the outer side in the tire axial direction; and a non-folded ply that terminates in front of the bead core without being folded around the bead core; A main body portion extending between the bead cores in a toroidal shape, and a pair of folded portions folded around the bead core, wherein the bead portion includes the body portion and the folded portion of the folded ply from the bead core. A first apex extending in the radial direction of the tire through the space and a tire of the folded portion of the folded ply A second apex that is arranged in contact with the outer side in the direction of the tire and extends in a tapered shape outward in the radial direction of the tire. An outer end of the first apex in the tire radial direction is an outer side in the tire radial direction of the second apex. It is located inside the tire radial direction from the end.

  In the pneumatic tire according to the present invention, it is preferable that the non-turned ply terminates through an inner side in the tire axial direction of the first apex.

  In the pneumatic tire according to the present invention, it is preferable that the end portion of the non-turned ply is located at a height of 20 to 25 mm from the bead base line.

  In the pneumatic tire according to the present invention, a belt layer made of a metal cord is disposed on the tread portion on the outer side in the tire radial direction of the carcass, and an end portion of the folded ply has the belt layer and the It is desirable to be located between the carcass.

  In the pneumatic tire according to the present invention, the height of the first apex from the bead base line is preferably 20 to 30 mm, and the height of the second apex from the bead base line is preferably 60 to 80 mm. .

  The pneumatic tire of the present invention includes a tread portion, a pair of bead portions each having a bead core embedded therein, and a carcass having a carcass cord straddling between the pair of bead portions. The carcass includes a folded ply that is folded around each bead core from the inner side toward the outer side in the tire axial direction, and a non-folded ply that terminates in front of the bead core without being folded around the bead core.

  The folded ply has a main body part extending in a toroidal manner between the bead cores and a pair of folded parts folded around the bead cores. Since such a folded ply is held by a pair of bead cores and tension is increased, high sidewall rigidity can be exhibited. Further, the non-folded ply can enhance the sidewall rigidity together with the folded ply. In addition, since the non-turned ply terminates before the bead core, it is possible to prevent an increase in tire weight while preventing the sidewall rigidity from becoming excessively high. Therefore, these carcasses can increase the rigidity of the sidewall without increasing the rubber volume of the sidewall portion, for example, so that the ride comfort and weight reduction can be maintained.

  The bead portion is disposed in contact with the outer side in the tire axial direction of the folded portion of the folded ply and the first apex extending from the bead core between the main portion and the folded portion of the folded ply and extending outward in the tire radial direction. In addition, a second apex extending in a tapered shape is arranged on the outer side in the tire radial direction. Such first apex and second apex can increase bead rigidity and sidewall rigidity. Furthermore, since the first apex and the second apex can firmly hold the folded portion of the folded ply, the sidewall rigidity can be further increased.

  The outer end of the first apex in the tire radial direction is located on the inner side in the tire radial direction of the second apex in the tire radial direction. Thereby, since the 1st apex is arranged in the tire radial direction inner side rather than the 2nd apex, it can prevent that sidewall rigidity becomes high too much. Thereby, the 1st apex can prevent an increase in tire weight, maintaining riding comfort.

  As described above, according to the pneumatic tire of the present invention, high sidewall rigidity can be exhibited while maintaining riding comfort and weight reduction.

It is sectional drawing which shows an example of the pneumatic tire of this embodiment. It is an enlarged view of the bead part and side wall part of FIG. (A) is sectional drawing of the tire of the comparative example 1, (b) is sectional drawing of the tire of the comparative example 2. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a tire meridian cross-sectional view including a tire rotation axis in a normal state of a pneumatic tire (hereinafter, simply referred to as “tire”) 1 of the present embodiment. Here, the normal state is a no-load state in which a tire is assembled on a normal rim (not shown) and filled with a normal internal pressure. Hereinafter, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in this normal state.

  The “regular rim” is a rim determined for each tire in a standard system including a standard on which a tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, For ETRTO, "Measuring Rim".

  The “regular internal pressure” is the air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based, and is “maximum air pressure” for JATMA, and “TIRE LOAD” for TRA. The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” in the case of ETRTO.

  The tire 1 according to the present embodiment includes a tread portion 2, a pair of bead portions 3 and 3, and a carcass 4. The tire 1 of the present embodiment is configured as a light truck tire.

  In the tread portion 2, a belt layer 5 is disposed outside the carcass 4 in the tire radial direction. The belt layer 5 includes two belt plies 5A and 5B inside and outside the tire in the radial direction of the tire. The belt plies 5A and 5B are formed by arranging metal cords (not shown) at an angle of 15 to 40 degrees with respect to the tire circumferential direction, for example. These belt plies 5A and 5B are overlaid so that the metal cords cross each other. Although the case where it is a steel cord is illustrated as a metal cord, it is not limited to such an aspect.

  A bead core 6 is embedded in each of the pair of bead portions 3 and 3. Each bead core 6, 6 is formed, for example, by winding a steel bead wire (not shown) in multiple rows and multiple stages. The bead cores 6 and 6 of this embodiment are formed in a substantially hexagonal shape having a horizontally long cross section. As a result, the bead cores 6 and 6 can stably sandwich the folded ply 7 described later of the carcass 4 between the rim seat surface (not shown) of the rim.

  The carcass 4 includes a folded ply 7 and a non-folded ply 8. In FIG. 1, the non-turned ply 8 is shown colored for easy understanding. The folded ply 7 and the non-folded ply 8 have carcass cords (not shown) arranged at an angle of 75 to 90 degrees with respect to the tire equator C, for example. The folded ply 7 and the non-folded ply 8 are overlapped so that the carcass cords intersect each other. The carcass cord is covered with a topping rubber (not shown). As the carcass cord, for example, an organic fiber cord such as aromatic polyamide or rayon can be adopted.

  The folded ply 7 is folded around the bead cores 6 from the inner side to the outer side in the tire axial direction. The folded ply 7 of the present embodiment includes, on the tire equator C, an inner folded ply 7A disposed on the inner side in the tire radial direction and an outer folded ply 7B disposed on the outer side in the tire radial direction of the inner folded ply 7A. Has been.

  The inner folded ply 7A includes a main body portion 7Aa extending between the bead cores 6 and 6 in a toroid shape, and a pair of folded portions 7Ab folded around the bead cores 6 and 6, respectively. The outer folded ply 7B includes a main body portion 7Ba extending between the bead cores 6 and 6 in a toroid shape, and a pair of folded portions 7Bb folded around the bead cores 6 and 6, respectively.

  Since the folded ply 7 (the inner folded ply 7A and the outer folded ply 7B) is held by the pair of bead cores 6 and 6, the tension is increased by thermal contraction of the carcass cord (not shown) during vulcanization. It is done. Therefore, the folded ply 7 can exhibit high sidewall rigidity (longitudinal rigidity and lateral rigidity). Moreover, since the folded ply 7 of the present embodiment is composed of two carcass plies (that is, the inner folded ply 7A and the outer folded ply 7B), the sidewall rigidity can be effectively increased.

  The end portion 7At of the inner folded ply 7A of the present embodiment is located between the belt layer 5 and the carcass 4. The inner turn-up ply 7A having such a high turn-up structure exhibits high sidewall rigidity because both the main body portion 7Aa and the turn-up portion 7Ab are arranged over a wide range of the bead portion 3 and the sidewall portion 10. sell. Further, since the end 7At of the inner folded ply 7A is held between the belt layer 5 and the carcass 4 (non-folded ply 8), the inner folded ply is caused by thermal contraction of the carcass cord (not shown) during vulcanization. The tension of the ply 7A is further increased. Therefore, the inner folded ply 7A can effectively increase the sidewall rigidity.

  The distance L1 in the tire axial direction between the end 7At of the inner folded ply 7A and the outer end 5t in the tire axial direction of the belt layer 5 can be set as appropriate. When the distance L1 is small, the end portion 7At of the inner folded ply 7A is not sufficiently held between the belt layer 5 and the carcass 4, and the sidewall rigidity may not be sufficiently increased. On the other hand, even if the distance L1 is large, the weight of the inner folded ply 7A increases, and the tire weight may increase. From such a viewpoint, the distance L1 is preferably 20 mm or more, and preferably 40 mm or less. Further, the height H1 of the end portion 7At of the inner folded ply 7A from the bead base line BL is desirably 80 to 120 mm. The “bead base line BL” is defined as a tire axial line passing through a rim diameter defined by the JATMA standard.

  FIG. 2 is an enlarged view of the bead portion 3 and the sidewall portion 10 of FIG. As shown in FIG. 2, the end portion 7Bt of the outer folded ply 7B is located on the inner side in the tire radial direction than the end portion 7At (shown in FIG. 1) of the inner folded ply 7A. Furthermore, the end portion 7Bt of the outer folded ply 7B is located on the inner side in the tire radial direction than the outer end 12t in the tire radial direction of the second apex 12 described later. Accordingly, the outer folded ply 7B can prevent the sidewall rigidity from becoming unnecessarily large, and thus can maintain the riding comfort. Further, since the outer folded ply 7B has a smaller weight than the inner folded ply 7A, an increase in tire weight can be suppressed.

  In order to effectively exhibit such an action, the height H2 of the end portion 7Bt of the outer folded ply 7B from the bead base line BL is preferably 20 mm or more, and preferably 25 mm or less.

  As shown in FIG. 1, the folded ply 7 of the present embodiment is composed of two carcass plies (an inner folded ply 7A and an outer folded ply 7B). Only the folded ply 7A) may be used.

  The non-turning ply 8 extends in a toroidal shape between the bead cores 6 and 6 and terminates in front of the bead core 6 without being folded around the bead core 6 (that is, outside the bead core 6 in the tire radial direction). Such a non-folded ply 8 and the folded ply 7 can increase the sidewall rigidity and the bead rigidity. Further, since the non-folded ply 8 is not held by the pair of bead cores 6, 6, the tension can be reduced compared to the folded ply 7. Thereby, the non-folding ply 8 helps to maintain the riding comfort. Further, the non-folded ply 8 has a smaller weight than the folded ply 7. Thereby, the non-folding ply 8 is useful for maintaining the weight reduction.

  The non-folded ply 8 of this embodiment is terminated through the inner side in the tire axial direction of a first apex 11 described later. Thereby, the non-folding ply 8 can contact over the wide range of the main body part 7Ba of the outer folding ply 7B and the folding part 7Ab of the inner folding ply 7A. Such a non-turned ply 8 can increase the tension by the thermal contraction of a carcass cord (not shown) during vulcanization, and thereby can exert a strong tension on the inner folded ply 7A and the outer folded ply 7B. Thereby, the non-folding ply 8 can effectively increase the sidewall rigidity and the bead rigidity.

  The non-turned ply 8 of the present embodiment is integrated in the sidewall portion 10 between the folded portion 7Ab of the inner folded ply 7A and the main body portion 7Ba of the outer folded ply 7B. Thereby, the non-folding ply 8 can effectively increase the sidewall rigidity and the bead rigidity together with the inner folding ply 7A and the outer folding ply 7B.

  The non-folding ply 8 of the present embodiment is held between the first apex 11 and the main body portion of the folding ply 7 (in this embodiment, the main body portion 7Aa of the inner folding ply 7A and the main body portion 7Ba of the outer folding ply 7B). Has been. Thereby, since the tension | tensile_strength is effectively raised by the thermal contraction of the carcass cord (illustration omitted) at the time of vulcanization | cure, the non-folding ply 8 can improve sidewall rigidity and bead rigidity.

  In order to effectively exhibit such an action, the end portion 8t of the non-turned ply 8 is desirably located at a height of 20 to 25 mm from the bead base line BL. If the height H3 exceeds 25 mm, the sidewall rigidity may not be sufficiently increased. Conversely, if the height H3 is less than 20 mm, the weight reduction of the tire 1 may not be sufficiently maintained.

  Thus, for example, the carcass 4 of the present embodiment exhibits high sidewall rigidity due to the synergistic effect of the folded ply 7 and the non-folded ply 8 without increasing the rubber volume of the sidewall portion 10. Therefore, the ride comfort and the weight reduction of the tire 1 can be maintained.

  As shown in FIG. 1, in the tire 1 of the present embodiment, a first apex 11 and a second apex 12 are arranged in the bead portion 3. The first apex 11 and the second apex 12 are made of hard rubber.

  The first apex 11 is located between the bead core 6 and the main body portion of the folded ply 7 and the folded portion (in this embodiment, between the main body portions 7Aa and 7Ba and the folded portions 7Ab and 7Bb of the inner folded ply 7A and the outer folded ply 7B). ) And tapering outward in the tire radial direction. The first apex 11 of the present embodiment is formed in a substantially triangular cross section.

  Such a first apex 11 can reinforce the bead portion 3 and increase the bending rigidity of the bead portion 3. Further, since the first apex 11 is tapered outward in the tire radial direction, the rigidity change of the bead portion 3 can be made smooth in the tire radial direction. Moreover, the first apex 11 can prevent the sidewall rigidity from becoming excessively high. Thereby, the 1st apex 11 can maintain riding comfort.

  In order to effectively exhibit such an action, the rubber hardness of the first apex 11 is preferably set to 80 to 95 °. In the present specification, the “rubber hardness” is measured with a JIS durometer type A in an environment of a temperature of 23 ° C. in accordance with JIS K6253.

  In addition, the outer end 11t of the first apex 11 in the tire radial direction is preferably located on the inner side in the tire radial direction of the outer end 12t of the second apex 12 in the tire radial direction. As a result, the first apex 11 can be prevented from excessively increasing the sidewall rigidity, so that riding comfort can be maintained. Furthermore, it is possible to prevent a large rigidity step that tends to occur when the outer end 11t of the first apex 11 and the outer end 12t of the second apex 12 are close to each other.

  The height H4 from the bead base line BL of the outer end 11t of the first apex 11 can be appropriately set as long as it is located on the inner side in the tire radial direction than the outer end 12t of the second apex 12. If the height H4 is small, the bead rigidity may not be sufficiently high. On the other hand, if the height H4 is large, the sidewall rigidity increases and the ride comfort may deteriorate. From such a viewpoint, the height H4 is preferably 20 mm or more, and preferably 30 mm or less.

  The second apex 12 is disposed in contact with the outer side in the tire axial direction of the folded portion of the folded ply 7 (in this embodiment, the folded portion 7Bb of the outer folded ply 7B), and the second apex 12 has a tire radius. Tapered outward in the direction. Further, the second apex 12 of the present embodiment extends in a tapered manner on the inner side in the tire radial direction.

  Such a second apex 12 can reinforce the rigidity of the bead portion 3 together with the first apex 11. Therefore, the second apex 12 can exhibit high bead rigidity. Moreover, since the outer end 12t of the second apex 12 is disposed on the outer side in the tire radial direction than the outer end 11t of the first apex 11, the rigidity of the sidewall portion 10 can be reinforced. Therefore, the second apex 12 can further exhibit high sidewall rigidity.

  In addition, since the second apex 12 is formed in a tapered shape both on the outer side in the tire radial direction and on the inner side in the tire radial direction, the rigidity change in the tire radial direction is smoothed in the bead part 3 and the sidewall part 10. can do. Thereby, since the 2nd apex 12 can prevent that bead rigidity and sidewall rigidity become high too much, it can maintain riding comfort.

  Further, the second apex 12 and the first apex 11 firmly sandwich the folded portion of the folded ply 7 (in this embodiment, the folded portion 7Ab of the inner folded ply 7A and the folded portion 7Bb of the outer folded ply 7B). Can be retained. As a result, the first apex 11 and the second apex 12 can effectively increase the tension of the folded ply 7 by the thermal contraction of the carcass cord (not shown) during vulcanization. Can be increased.

  Thus, according to the tire 1 of the present embodiment, riding comfort, weight reduction, and sidewall rigidity are achieved by the synergistic effect of the folded ply 7, the non-folded ply 8, the first apex 11, and the second apex 12. Can be achieved at a high level.

  The rubber hardness of the second apex 12 can be set as appropriate. The rubber hardness of the second apex 12 of the present embodiment is desirably set smaller than the rubber hardness of the first apex 11. As a result, the second apex 12 can be prevented from excessively increasing the sidewall rigidity, so that riding comfort can be maintained. In order to effectively exhibit such an action, the difference between the rubber hardness of the second apex 12 and the rubber hardness of the first apex 11 is preferably 0 to 10 °.

  Further, the height H5 of the outer end 12t of the second apex 12 from the bead base line BL can be appropriately set as long as it is located on the outer side in the tire radial direction from the outer end 11t of the first apex 11. . If the height H5 is small, the sidewall rigidity may not be sufficiently high. On the other hand, even if the height H5 is large, the sidewall rigidity increases, and there is a possibility that the riding comfort cannot be maintained. From such a viewpoint, the height H5 is preferably 60 mm or more, and preferably 80 mm or less.

  The inner end 12 s of the second apex 12 in the tire radial direction is preferably disposed on the inner side in the tire radial direction than the end 8 t of the non-turned ply 8. Thus, the second apex 12 has both sidewall rigidity and bead rigidity while preventing a rigidity step that tends to occur due to the proximity of the inner end 12 s of the second apex 12 and the end 8 t of the non-turned ply 8. It can be increased evenly. Further, the inner end 12 s of the second apex 12 is preferably disposed on the outer side in the tire radial direction than the bead core 6. Thereby, it is possible to prevent a rigid step that tends to occur due to the proximity of the inner end 12s of the second apex 12 and the bead core 6.

  About the overlap length L4 of the tire radial direction with the 1st apex 11 and the 2nd apex 12, it can set suitably. If the overlap length L4 is small, the sidewall rigidity may not be sufficiently high. On the contrary, even if the overlap length L4 is large, the sidewall rigidity becomes excessively large, and the ride comfort may be deteriorated. From such a viewpoint, the overlapping length L4 is preferably 5 mm or more, and preferably 15 mm or less.

  The bead portion 3 of this embodiment is further provided with a clinch rubber 13 and a chafer rubber 14.

  The clinch rubber 13 is disposed on the outer side in the tire axial direction of the second apex 12. Such clinch rubber 13 is useful for preventing wear and damage of the bead portion 3 due to contact with a rim (not shown). In order to effectively exhibit such an action, it is desirable that the rubber hardness of the clinch rubber 13 is set to 65 to 80 °.

  As shown in FIG. 2, the outer end 13t of the clinch rubber 13 in the tire radial direction is outside the outer end 11t of the first apex 11 in the tire radial direction, and more than the outer end 12t of the second apex 12 in the tire radial direction. Arranged inside. Thereby, the clinch rubber 13 can prevent the sidewall rigidity from being excessively increased while increasing the bead rigidity. The height H7 of the outer end 13t of the clinch rubber 13 from the bead base line BL is preferably 40 to 60 mm.

  The chafer rubber 14 includes a base portion 16 exposed on the bottom surface of the bead, a rising portion 17 extending from the inner side in the tire axial direction of the base portion 16 to the outer side in the tire radial direction, and an outer side in the tire radial direction from the outer side in the tire axial direction of the base portion 16 And an outer rising portion 18 extending from the outside. Such chafer rubber 14 can prevent damage due to contact with the rim while exhibiting a high and stable fitting pressure with respect to the rim (not shown). In order to effectively exhibit such an action, the rubber hardness of the chafer rubber 14 is desirably set to 70 to 85 °.

  As shown in FIG. 2, the outer end 17 t in the tire radial direction of the inner rising portion 17 is arranged on the outer side in the tire radial direction than the end portion 8 t of the non-turned ply 8. Accordingly, it is possible to prevent a rigid step that tends to occur due to the proximity of the outer end 17t of the inner rising portion 17 and the end portion 8t of the non-turned ply 8. Further, an outer end 18 t in the tire radial direction of the outer rising portion 18 is disposed on the outer side in the tire radial direction with respect to the inner end 12 s of the second apex 12. Accordingly, it is possible to prevent a rigid step that tends to occur due to the proximity of the outer end 18t of the outer rising portion 18 and the inner end 12s of the second apex 12.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

A tire (light truck tire) having the basic structure shown in FIG. 1 and including the carcass, the first apex, and the second apex shown in Table 1 was manufactured, and their performance was evaluated (Example 1). ~ 6). Note that the rubber hardness of the second apex of Example 5 is set to be smaller than the rubber hardness of the first apex. For comparison, a tire not including the non-turned ply and the second apex shown in FIG. 3A was manufactured (Comparative Example 1). In addition, a tire that does not include the non-turned ply shown in FIG. 3B and includes the second apex was manufactured (Comparative Example 2). The specifications common to each example and comparative example are as follows.
Tire size: 265 / 70R17
Rim size: 17 × 7.5J
Internal pressure: 240kPa
Vehicle: Light truck Load: 7.01N
First apex rubber hardness: 86 °
Outer folded ply end height H2: 20 mm
Clinch rubber outer edge height H7: 60mm
The test method is as follows.

<Powerful carcass>
Each test tire was assembled on the rim, filled with the internal pressure, and mounted on all the wheels of the vehicle. Then, the tire test course was traveled by the vehicle for a distance of about 60 km, and then the tire was disassembled, and five tires were taken out from the inner folded ply, the outer folded ply and the non-folded ply. And according to “tensile strength and elongation” described in Section 8.5 of JIS L1017 (chemical fiber tire cord test method), the load at the time of breaking of the carcass cord taken out was measured, and the average value thereof. Was calculated. The results were expressed as an index with the average value of Example 1 as 100. The larger the value, the stronger the carcass and the better the durability.

<Tire longitudinal rigidity>
Each test tire was assembled on the rim, filled with the internal pressure, and a tire static test machine was used to apply a load of 7.01 N to the test tire to measure the longitudinal spring constant of the tire. . The results were expressed as an index with Example 1 as 100. The larger the value, the greater the sidewall rigidity and the better.

<Tire lateral stiffness>
Each test tire was assembled on the rim, filled with the internal pressure, and a tire static test machine was used to apply a load of 7.01 N to the test tire to measure the lateral spring constant of the tire. The results were expressed as an index with Comparative Example 2 as 100. The higher the value, the greater the sidewall rigidity and the better

<Tire weight>
The weight per tire was measured. The results are displayed as an index with the reciprocal of Example 2 as 100. The larger the value, the better.

<Ride comfort>
Each test tire was assembled on the rim, filled with the internal pressure, and mounted on all the wheels of the vehicle. Then, two people ride on test courses such as stepped roads on dry asphalt roads, Belgian roads (cobblestone roads), Bitzman roads (roads covered with pebbles), and sensory evaluations are made regarding ruggedness, pushing up, and dumping. It was. The results are displayed as an index with Example 2 as 100. The larger the value, the better.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the example can exhibit higher sidewall rigidity while maintaining the ride comfort and lighter weight than the comparative example.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Bead part 4 Carcass 6 Bead core 7 Folding ply 8 Nonfolding ply 11 1st apex 12 2nd apex

Claims (5)

A pneumatic tire comprising a tread portion, a pair of bead portions each embedded with a bead core, and a carcass having a carcass cord straddling between the pair of bead portions,
The carcass includes a folded ply folded around the respective bead cores from the inner side to the outer side in the tire axial direction, and a non-folded ply that terminates in front of the bead core without being folded around the bead core,
The folded ply has a main body portion extending in a toroidal manner between the bead cores, and a pair of folded portions folded around the bead core,
In the bead part,
A first apex extending from the bead core to the outer side in the tire radial direction passing between the body portion and the folded portion of the folded ply;
A second apex arranged in contact with the outer side in the tire axial direction of the folded portion of the folded ply and extending in a tapered shape on the outer side in the tire radial direction;
A pneumatic tire in which an outer end in a tire radial direction of the first apex is located on an inner side in the tire radial direction with respect to an outer end in the tire radial direction of the second apex.   The pneumatic tire according to claim 1, wherein the non-turned ply is terminated through an inner side in the tire axial direction of the first apex.   The pneumatic tire according to claim 1 or 2, wherein an end portion of the non-turned ply is located at a height of 20 to 25 mm from a bead base line. In the tread portion, a belt layer made of a metal cord is arranged on the outer side in the tire radial direction of the carcass,
The pneumatic tire according to any one of claims 1 to 3, wherein an end portion of the folded ply is positioned between the belt layer and the carcass.   5. The pneumatic according to claim 1, wherein a height of the first apex from a bead base line is 20 to 30 mm, and a height of the second apex from a bead base line is 60 to 80 mm. tire.

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