JP2023091168A - pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire which can easily reduce air resistance of the tire during traveling of a vehicle and easily reduce fuel consumption of the vehicle.SOLUTION: A tire 1 includes: a tread 10 having a ground contact surface 10a; a first buttress 11a disposed at a vehicle outer side relative to the tread 10; and a second buttress 11b disposed at the vehicle inner side than the tread 10. A first thickness of the first buttress 11a disposed at a vehicle inner side of the tire 1 is set so as to be thinner than a second thickness of the second buttress disposed at the vehicle outer side of the tire 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to pneumatic tires.

BACKGROUND ART Conventionally, there is a pneumatic tire described in Patent Document 1. In this pneumatic tire, the radius of curvature of the contour of the buttress on the vehicle outer side is smaller than that of the contour of the buttress on the inner side of the vehicle, and the contact width of the buttress on the outer side of the vehicle is larger than the contact width of the buttress on the inner side of the vehicle. are doing. In this way, the contact area of the vehicle-outside buttress is increased, and the uneven wear resistance of the vehicle-outside buttress, which receives a large force when the vehicle turns, is improved.

JP-A-11-321214

If the air resistance of the tires can be reduced while the vehicle is running, the fuel consumption of the vehicle can be reduced. However, even with reference to Patent Literature 1, it is not possible to obtain any knowledge about the configuration for reducing the air resistance of the tire when the vehicle is running. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic tire that can reduce the air resistance of the tire when the vehicle is running and facilitates reducing the fuel consumption of the vehicle.

A pneumatic tire according to the present invention includes a tread having a ground-contacting surface, a first buttress arranged inside the vehicle from the tread, and a second buttress arranged outside the tread. is less than the second thickness of the second buttress.

The tire has an annular first rib on the inner side in the width direction and a second annular rib on the outer side in the width direction. The first thickness of the first buttress is defined as the thickness of the location where the first rib exists on the inner side of the pneumatic tire in the width direction, and the second thickness of the second buttress is defined as the thickness of the outer side of the pneumatic tire in the width direction. It is defined as the thickness where the second rib exists. Further, it is assumed that the vehicle inner side and the vehicle outer side are expressed in a state in which pneumatic tires are appropriately mounted on the vehicle.

In a pneumatic tire mounted on a vehicle, the widthwise outer portion located on the outside of the vehicle is more likely to be hit by the wind from the front of the vehicle than the widthwise inner portion located on the inside of the vehicle, and is more susceptible to air resistance. . With this background, according to the present invention, the thickness of the second buttress (second shoulder) on the vehicle outer side is greater than the thickness of the first buttress (first shoulder) on the vehicle inner side. Therefore, since the rigidity of the second buttress on the outer side of the vehicle is high, it is possible to prevent the second buttress on the outer side of the vehicle from rising when the vehicle is traveling, particularly when the vehicle is turning where a large centrifugal force acts or when the vehicle is traveling at high speed. Therefore, the second buttress can easily maintain its round shape while the vehicle is running, so that the air resistance that the second buttress receives while the vehicle is running can be reduced. As a result, the air resistance of the second buttress, which greatly affects the air resistance of the entire pneumatic tire, can be reduced, so the air resistance of the entire pneumatic tire can be efficiently reduced, and the fuel consumption of the vehicle can be easily reduced.

According to the pneumatic tire according to the present disclosure, the air resistance of the tire can be reduced while the vehicle is running, and the fuel consumption of the vehicle can be easily reduced.

1 is a half cross-sectional view including the width direction and the radial direction of a pneumatic tire according to an embodiment of the present invention; FIG. It is a figure explaining vulcanization molding of a tire. FIG. 2 is an enlarged cross-sectional view showing the peripheral portion of the first buttress located on the anti-serial side in the width direction of the pneumatic tire in the cross section of FIG. 1 ; 2 is an enlarged cross-sectional view showing a peripheral portion of a second buttress located on the serial side in the width direction of the pneumatic tire in the cross section of FIG. 1; FIG. It is a schematic diagram explaining the layer structure of a cap ply and an edge ply. It is a figure explaining the moving direction of a vehicle, and the flow direction of a wind. FIG. 4 is a diagram illustrating forces that normal pneumatic tires receive from the wind and the vehicle body when the vehicle is turning. FIG. 4 is a diagram illustrating forces that a pneumatic tire of the present disclosure receives from wind and a vehicle body when the vehicle is turning;

Embodiments according to the present disclosure will be described in detail below with reference to the accompanying drawings. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that the characteristic portions thereof will be appropriately combined to construct a new embodiment. Further, in the following embodiments, the same reference numerals are given to the same configurations in the drawings, and redundant explanations are omitted. In addition, a plurality of drawings include schematic diagrams, and the dimensional ratios of length, width, height, etc. of each member do not necessarily match between different drawings.

In addition, among the constituent elements described below, constituent elements that are not described in independent claims indicating the highest concept are optional constituent elements and are not essential constituent elements. In addition, the present disclosure is not limited to the following embodiments and modifications thereof, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents.

Further, in the following description, the width direction is the width direction of the pneumatic tire 1, the radial direction is the radial direction of the pneumatic tire, and the circumferential direction is the circumferential direction of the pneumatic tire. The width direction, radial direction, and circumferential direction are orthogonal to each other. Further, in the following description, when the inside of the vehicle and the outside of the vehicle are mentioned, it is assumed that the pneumatic tire 1 is appropriately mounted on the vehicle.

FIG. 1 is a half-sectional view including the width direction and the radial direction of a pneumatic tire 1 according to one embodiment of the present invention. As shown in FIG. 1, a pneumatic tire (hereinafter simply referred to as a tire) 1 includes a tread 10, a pair of buttresses (a pair of shoulders) 11a and 11b, a pair of sidewalls 12a and 12b, and a pair of beads 13a and 13b. Prepare. The tread 10 includes a ground-contacting surface 10a that is arranged in the center in the width direction and contacts the road surface. The tread 10 is made of, for example, crosslinked rubber. A plurality of grooves 24 are provided on the outer peripheral surface of the tread 10 . As is well known, the plurality of grooves 24 play a role of draining rainwater that has entered between the road surface and the tire 1 and securing a contact area between the road surface and the tire 1 .

The first buttress 11a, the first sidewall 12a, and the first bead 13a form a side surface of the tire 1 on the anti-serial side (the vehicle side when the tire 1 is mounted on the vehicle). The second buttress 11b, the second sidewall 12b, and the second bead 13b form a side surface of the tire 1 on the serial side (the side opposite to the vehicle when the tire 1 is mounted on the vehicle).

The first buttress 11a, the first sidewall 12a, and the first bead 13a extend radially inward from the end of the tread 10 on the anti-serial side (tire inner side) in the width direction. The second buttress 11b, the second sidewall 12b, and the second bead 13b extend radially inward from the widthwise end of the tread 10 on the serial side (tire outer side). An annular tread rubber 61, an annular first sidewall rubber 62, an annular first buttress rubber 63, an annular second sidewall rubber 64, and an annular second buttress rubber 65 are pasted together on the outer peripheral surface of the tire 1. consists of The tread rubber 61 includes a ground-contacting surface, and the first sidewall rubber 62 includes a first maximum width position 66 inside the vehicle. The first buttress rubber 63 is positioned between the center 67 in the width direction and the first maximum width position 66 in the width direction. The second sidewall rubber 64 includes a second maximum width position 68 on the outside of the vehicle, and the second buttress rubber 65 is positioned between the widthwise center 67 and the second maximum width position 68 in the width direction. do. In the present embodiment, the widthwise inner first ground contact edge Ea of the tire 1 is defined as the boundary position between the tread 10 and the first buttress 11a on the outer peripheral surface of the tire 1, and the widthwise outer second ground contact edge Eb of the tire 1 is defined as the boundary position between the tread 10 and the second buttress 11b on the outer peripheral surface of the tire 1. A boundary position between the first sidewall rubber 62 and the first buttress rubber 63 on the outer peripheral surface of the tire 1 is defined as a boundary position between the first buttress 11 a and the first sidewall 12 a on the outer peripheral surface of the tire 1 . A boundary position between the second sidewall rubber 64 and the second buttress rubber 65 on the outer peripheral surface of the tire 1 is defined as a boundary position between the second buttress 11b and the second sidewall 12b on the outer peripheral surface of the tire 1 . The sidewalls 12a, 12b are rubber layers between the buttresses 11a, 11b and the beads 13a, 13b, and are the portions of the tire 1 that bend the most. The sidewalls 12a, 12b serve to protect the carcass 15 and prevent its elongation. The ground contact edges Ea and Eb refer to both width direction ends of a portion that touches the ground when the tire 1 is mounted on a regular rim, the internal pressure is adjusted to the regular internal pressure, and a regular load is applied. Same as described in Japanese Patent Application Laid-Open No. 2020-131965).

The buttresses 11 a and 11 b are shoulder portions of the tire 1 , projecting outward in the width direction from both ends in the width direction of the tread 10 and extending inward in the radial direction. The buttresses 11a and 11b are provided annularly along the circumferential direction, similarly to the tread 10. As shown in FIG. The sidewalls 12a, 12b extend radially inward from the buttresses 11a, 11b on both sides in the width direction, and are annularly provided along the circumferential direction. The sidewalls 12a, 12b include portions that protrude most outward in the width direction of the tire 1, and are gently curved so as to protrude outward.

The beads 13a, 13b extend radially inward from the sidewalls 12a, 12b on both sides in the width direction, and are annularly formed along the circumferential direction. The beads 13 a and 13 b are portions fixed to the rim of the wheel and constitute the inner peripheral portion of the tire 1 . The beads 13a and 13b are gently curved so as to protrude inward and are located on the inner side in the width direction of the sidewalls 12a and 12b.

The tire 1 includes bead cores 26a, 26b and bead fillers 27a, 27b. The first bead core 26a and the first bead filler 27a are provided on the first bead 13a on the anti-serial side of the tire 1 . The second bead core 26b and the second bead filler 27b are provided on the second bead 13b on the serial side of the tire 1 . The bead cores 26a and 26b are ring-shaped members in which bundled steel wires are covered with rubber. The bead fillers 27a and 27b are made of hard rubber and have the function of increasing the rigidity of the beads 13a and 13b. The bead fillers 27a, 27b are arranged radially outside the bead cores 26a, 26b.

FIG. 2 is a diagram illustrating vulcanization molding of the tire 1. FIG. As shown in FIG. 2 , the tire 1 is manufactured using a tire vulcanization mold (hereinafter simply referred to as “mold”) 30 . The mold 30 has an annular shape. The mold 30 molds the outer surface of the tire 1 . In FIG. 2 the mold 30 is shown together with the vulcanized tire 1 .

The left side portion of the mold 30 in FIG. 2 is a portion that vulcanizes and molds the tire 1 on the opposite side of the tire 1 in the width direction. 2 of the mold 30 is a portion for vulcanizing and molding the serial side of the tire 1 in the width direction.

The mold 30 includes a cylindrical sector mold 31 and a pair of annular side molds 32 a and 32 b positioned radially inside the sector mold 31 . A pair of side molds 32a and 32b are arranged with a gap in the width direction. The first side mold 32a is used to vulcanize and mold the anti-serial side in the width direction of the tire 1, and has an annular first side plate 36a and an annular first bead ring 38a. The second side mold 32b is used to vulcanize the serial side in the width direction of the tire 1, and has an annular second side plate 36b and an annular second bead ring 38b.

The sector mold 31 and the side molds 32a, 32b have substantially the same axis A extending in the width direction. An internal space defined by the sector mold 31 and the pair of side molds 32a and 32b constitutes a cavity 33 in which a green tire before vulcanization that constitutes the tire 1 is set. After setting the green tire in the cavity 33, a high temperature gas such as high temperature steam is supplied to the cavity 33 through a supply pipe (not shown). In this way, the vulcanization process is applied to the green tire.

The sector mold 31 is movable about the axis A in the radial direction indicated by the arrow α. The inner peripheral surface of sector mold 31 includes a tread molding surface 35 for molding the outer peripheral surface of tread 10 . The pair of side plates 36 a and 36 b are arranged radially inside the sector mold 31 so as to be in contact with the sector mold 31 . The first side plate 36a is immovably fixed. The second side plate 36b is movable in the width direction indicated by arrow β by a drive mechanism (not shown). The inner surface of the first side plate 36a includes a first sidewall forming surface 37a that forms the outer surface of the first sidewall 12a on the counter-serial side, and the inner surface of the second side plate 36b includes the second side wall on the serial side. It includes a second sidewall molding surface 37b that molds the outer surface of sidewall 12b.

The first bead ring 38a is arranged radially inward and widthwise inward of the first side plate 36a so as to be able to contact the first side plate 36a in the width direction. The second bead ring 38b is arranged radially inward and widthwise inward of the second side plate 36b so as to be able to contact the second side plate 36b in the width direction. A first bead ring 38a is integral with the first side plate 36a and is non-movably fixed. On the other hand, the second bead ring 38b is integrated with the second side plate 36b and is movable in the width direction together with the second side plate 36b. The inner surface of the first bead ring 38a includes a first bead molding surface 39a that molds the outer surface of the first bead 13a. In addition, the inner surface of the second bead ring 38b includes a second bead molding surface 39b that molds the outer surface of the second bead 13b.

As shown in FIG. 2, the shape of the inner peripheral surface of the sector mold 31 is asymmetrical on both sides in the width direction. In addition, the shape of the inner forming surface positioned on the inner side in the width direction of the first side plate 36a is also different from the shape of the outer forming surface positioned on the inner side in the width direction of the second side plate 36b. Specifically, the tread forming surface 35 of the sector mold 31 is curved radially inward when going to the counter-serial side in the width direction compared to when going to the serial side in the width direction. In other words, the radial thickness of the sector mold 31 on the anti-serial side in the width direction is greater than the radial thickness on the serial side of the sector mold 31 in the width direction. Similarly, the widthwise thickness at the radially outer end of the first side plate 36a is greater than the widthwise thickness at the radially outer end of the second side plate 36b. It's getting thicker. That is, the inner surface of the mold 30 is curved in such a manner that the counter-serial side in the width direction protrudes toward the cavity 33 compared to the serial side in the width direction.

A first annular concave portion 41a having a beak-shaped cross section (triangular cross-section) is present inside the fitting portion between the sector mold 31 and the first side plate 36a. A second annular concave portion 41b having a beak-shaped cross section (triangular cross-section) is also present inside the fitting portion between the sector mold 31 and the second side plate 36b. For this reason, the tire 1 has annular ribs 51a, 51b (see FIGS. 3 and 4) corresponding to the annular recesses 41a, 41b on the buttresses 11a, 11b.

FIG. 3 is an enlarged cross-sectional view showing the peripheral portion of the first buttress 11a located on the anti-serial side in the width direction of the tire 1 in the cross section of FIG. 4 is an enlarged cross-sectional view showing the peripheral portion of the second buttress 11b located on the serial side in the width direction of the tire 1 in the cross section of FIG. As shown in FIGS. 3 and 4, the tire 1 comprises a carcass 15, a belt 16, a belt reinforcement 17 and an inner liner 18.

The carcass 15 is a cord layer covered with rubber. The carcass 15 includes carcass plies and forms a tire skeleton that withstands loads, impacts, air pressure, and the like. The carcass 15 has a radial structure in which carcass cords extending in a direction orthogonal to the circumferential direction are arranged. A rubber layer that covers and protects the carcass 15 is generally composed of a plurality of rubber materials such as tread rubber and sidewall rubber.

The carcass plies 15a, 15b constituting the carcass 15 are stretched over a pair of bead cores 26a, 26b from the inner side in the width direction, and are folded back toward the sidewalls 12a, 12b so as to wrap the bead cores 26a, 26b and the bead fillers 27a, 27b. . In the example shown in FIGS. 3 and 4, the carcass 15 includes two carcass plies 15a, 15b. As shown in FIG. 1, the ply end 24a of the first carcass ply 15a closer to the bead cores 26a, 26b is located on the beads 13a, 13b, and the ply end 24b of the second carcass ply 15b is located on the sidewalls 12a, 12b. Located in It should be noted that the carcass may have only one carcass ply, in which case the ply ends of the carcass ply are generally located on the sidewalls.

The inner liner 18 is a rubber layer for retaining air pressure, and is attached to the inner surface of the carcass 15 . The inner liner 18 is made of, for example, air permeable rubber, and prevents the air inside the tire cavity from leaking to the outside.

A belt 16 is arranged between the tread 10 and the carcass 15 . The belt 16 is installed on the entire area overlapping the tread 10 in the radial direction and partial areas of the buttresses 11a and 11b in the width direction. The belt 16 is a reinforcing band stretched in the circumferential direction, and strongly tightens the carcass 15 to increase the rigidity of the tread 10. - 特許庁The belt 16 is made of, for example, a steel belt containing steel cords, has a two-layer structure, and includes two steel belts 16a and 16b. However, the number of belts to be laminated is not limited to two, and belts including tire cords using aramid fibers may be used instead of steel belts. Alternatively, the belt may consist of only one layer. By providing the belt 16, the rigidity of the tire 1 can be ensured, and the contact state between the tread 10 and the road surface can be improved.

A belt reinforcement 17 is arranged between the belt 16 and the tread 10 . The belt reinforcing members 17 are arranged in the width direction over the entire area overlapping the tread 10 in the radial direction and in partial areas of the buttresses 11a and 11b. The widthwise outer end 22 of the belt reinforcing member 17 extends to the widthwise outer side of the belt 16 . The belt reinforcing member 17 has, for example, a three-layer structure, and includes one cap ply 17a and edge plies 17b, 17c, 17d, and 17e arranged in two layers at each end in the width direction.

Specifically, the cap ply 17a extends in the width direction from the radially inner side of the first buttress 11a to the radially inner side of the second buttress 11b. The two first edge plies 17b, 17c are arranged radially inside the first buttress 11a in two layers, and the two second edge plies 17c, 17d are arranged radially inside the second buttress 11b. Arranged in two layers. The cap ply 17a and the edge plies 17b, 17c, 17d, 17e are made of the same material, include an insulating organic fiber layer such as polyamide fiber, and are covered with a topping rubber. The belt reinforcing member 17 is installed for purposes such as improving durability and reducing road noise during running.

FIG. 5 is a schematic diagram illustrating the layer structure of the cap ply 17a and the edge plies 17b, 17c, 17d and 17e. Note that FIG. 5 shows the layer structure from the central portion in the width direction to the serial side. As shown in FIG. 5, edge plies 17d and 17e configured in two layers in addition to the cap ply 17a are arranged on the second buttress 11b. Therefore, the rigidity of the second buttress 11b can be increased, and deformation (climbing) of the second buttress 11b when centrifugal force is applied to the tire 1 can be effectively suppressed. Although the case where the edge plies 17d and 17e are arranged in two layers at the ends on the serial side in the width direction has been described, it is also possible to arrange only one layer of edge plies at each end in the width direction. A configuration in which edge plies are not arranged at each end is also possible.

Again referring to FIGS. 3 and 4, the rubber thicknesses of the buttresses 11a and 11b of the tire 1 differ between the serial side (tire outer side) and the anti-serial side (tire inner side). More specifically, as described above, the inner surface of the mold 30 is curved such that the widthwise counter-serial side protrudes toward the cavity 33 compared to the widthwise serial side (see FIG. 2). Correspondingly, as shown in FIGS. 3 and 4, the thickness (rubber thickness) Ho (see FIG. 4) of the second buttress 11b is the thickness (rubber thickness) of the first buttress 11a (see FIG. 3). Thickness) It is thicker than Hi.

The first buttress 11a has an annular first rib 51a corresponding to the annular recess 41a (see FIG. 2), and the second buttress 11b has an annular second rib 51b corresponding to the annular recess 41a (see FIG. 2). have In FIG. 3, the distance from the tip of the annular first rib 51a to the carcass 15, more specifically, the outer peripheral surface of the carcass 15 when the normal direction of the outer peripheral surface of the carcass 15 passes through the tip of the first rib 51a. Hi is the distance from the position to the tip of the first rib 51a. In FIG. 4, the distance from the tip of the second annular rib 51b to the carcass 15, more specifically, the normal direction of the outer peripheral surface of the carcass 15 passes through the tip of the second rib 51b. The distance from the position of the outer peripheral surface to the tip of the second rib 51b is Ho. However, the thickness of the first and second buttresses 11a, 11b is such that the thickness of the second buttress 11b is greater than the thickness of the first buttress 11a even at positions where the ribs 51a, 51b do not exist.

The first and second buttresses 11a, 11b may have any thickness provided Ho>Hi. However, in this embodiment, the first and second buttresses 11a and 11b have a thickness that satisfies the condition of 1 mm<(Ho-Hi)≦2 mm. The reason why it is preferable to satisfy this condition will be described below.

<Structure of Tire of Present Disclosure and Functions and Effects thereof>
[Essential configuration of the tire of the present disclosure and its effect]
The tire 1 includes a tread 10 having a ground contact surface 10a, a first buttress 11a arranged on the vehicle outer side of the tread 10, and a second buttress 11b arranged on the vehicle inner side of the tread 10. Also, the first thickness Hi of the first buttress 11a is thinner than the second thickness Ho of the second buttress 11a.

As shown in FIG. 6, when vehicles 90a and 90b move in the direction of arrow C, tires 91 and 1 receive wind flowing in the direction opposite to the moving direction of vehicles 90a and 90b shown in the direction of arrow D. do. At this time, if the tire 91 is a normal tire and has the same shape on the serial side and the anti-serial side, as shown in FIG. When the flow is generated, this turbulent flow receives force from the underside of the vehicle 90a, and a vortex indicated by arrow E is generated. Then, this vortex flows on the side of the tire in the same direction as the direction of travel, pushing the tire 91 in the direction of travel, and as a result, a propulsive force is generated. On the other hand, on the outside (OUT side) where the vehicle 90a does not exist, there is no object that imparts forward force to the turbulent flow, so when the turbulent flow indicated by arrow F occurs, the air resistance increases. More specifically, when the vehicle 90a is running at high speed or turning, the second buttress 91a rises due to centrifugal force on the serial side (OUT side), making it easier for air from the front to collide with the second buttress 91a. Therefore, air flow is likely to occur, further increasing air resistance.

On the other hand, if the tire 1 is the tire 1 of the present embodiment and the thickness of the second buttress 11b on the serial side is thicker than the thickness of the first buttress 11a on the anti-serial side, the serial side can increase the rigidity of the second buttress 11b. Therefore, the second buttress 11b on the outside of the vehicle can be prevented from rising when the vehicle is running, particularly when the vehicle is turning or when the vehicle is running at high speed when a large centrifugal force acts. Therefore, as shown in FIG. 8, the second buttress 11b can easily maintain the rounded shape while the vehicle is running, so that the air flow outside the vehicle 90b can be made smooth as indicated by the arrow G when the vehicle is running. , the air resistance that the second buttress 11b receives during running of the vehicle can be reduced. As a result, the air resistance of the second buttress 11b, which greatly affects the air resistance of the entire tire 1, can be reduced, so the air resistance of the entire tire 1 can be efficiently reduced, and the fuel consumption of the vehicle can be reduced.

Furthermore, in the present embodiment, simply by making the thickness of the second buttress 11b thicker than the thickness of the first buttress 11a, it is possible to effectively suppress the upward movement of the second buttress 11b when centrifugal force acts. , the air resistance of the tire 1 can be efficiently reduced without arranging an additional reinforcing member on the second buttress 11b. Therefore, there is no deterioration of rubber flow near the end of the member, which may be caused by arranging the additional reinforcing member on the second buttress 11b, and no defect occurs in the manufacturing process. .

[Preferred configuration and effects when employed in the tire of the present disclosure]
The tire 1 is arranged in two layers, the cap ply 17a extending in the width direction from the radially inner side of the first buttress 11a to the radially inner side of the second buttress 11b, and the radially inner side of the first buttress 11a. and two second edge plies 17d and 17e arranged in two layers radially inside the second buttress 11b.

According to this configuration, since the two layers of edge plies 17b, 17c, 17d, 17e are arranged inside the buttresses 11a, 11b, the rigidity of the buttresses 11a, 11b can be increased. Therefore, it is possible to more effectively suppress the rising of the buttresses 11a and 11b when the centrifugal force acts. Therefore, the round shape of the second buttress 11b can be more effectively maintained when centrifugal force acts, and the air resistance can be greatly reduced.

Further, it is preferable that 1 mm≦(second thickness Ho−first thickness Hi)≦2 mm.

If the difference between the second thickness Ho and the first thickness Hi becomes excessively large, the difference in rigidity between the inner tire rigidity and the outer tire rigidity increases, so that the tire deflection between the inner tire and the outer tire during cornering of the vehicle increases. As the difference increases, it becomes difficult to perform smooth cornering, and the ride comfort is likely to be affected. In addition, uneven wear tends to occur, and uniformity tends to deteriorate. On the other hand, when the difference between the second thickness Ho and the first thickness Hi is small, it becomes difficult to obtain the effects of the present disclosure.

On the other hand, according to this configuration, (second thickness Ho - first thickness Hi) ≤ 2 mm, so that the difference in rigidity between the rigidity of the inner side of the tire and the rigidity of the outer side of the tire does not become excessively large. It is possible to suppress the difference in tire deflection between the inner side and the outer side of the tire during cornering of the vehicle. Therefore, it is easy to perform smooth cornering, and it is difficult to achieve good ride comfort. In addition, uneven wear is less likely to occur, and uniformity is likely to be improved. Further, since 1 mm≦(second thickness Ho−first thickness Hi), the air resistance of the tire 1 can be greatly reduced when the vehicle is running, and the fuel consumption of the vehicle can be reliably reduced.

Reference Signs List 1 tire 10 tread 10a tread 11a first buttress 11b second buttress 12a first sidewall 12b second sidewall 13a first bead 13b second bead 15 carcass 15a first carcass ply 15b second carcass ply 16 belt 16a, 16b steel belt 17 belt reinforcement 17a cap ply 17b, 17c first edge ply 17d, 17e second edge ply 18 inner liner 26a first bead core 26b second bead core 27a first bead filler 27b second bead filler 30 mold 31 sector mold 32a first side mold 32b second side mold 33 cavity 36a first side plate 36b second side Plate 38a First bead ring 38b Second bead ring 41a First annular recess 41b Second annular recess 51a First rib 51b Second rib 90a, 90b Vehicle Hi Rubber thickness of first buttress Ho Rubber thickness of the second buttress.

Claims (3)

a tread having a ground-contacting surface;
a first buttress disposed on the inner side of the vehicle than the tread;
a second buttress disposed outside the vehicle from the tread,
A pneumatic tire, wherein a first thickness of said first buttress is less than a second thickness of said second buttress. a cap ply extending in the tire width direction from the radially inner side of the first buttress to the radially inner side of the second buttress;
two first edge plies arranged in two layers on the radially inner side of the first buttress;
two second edge plies arranged in two layers on the radially inner side of the second buttress;
The pneumatic tire of claim 1, comprising: 3. The pneumatic tire according to claim 1, wherein 1 mm≦(the second thickness−the first thickness)≦2 mm.

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