JP2012245905A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that can improve the rigidity while reducing the rolling resistance of the pneumatic tire.SOLUTION: A pneumatic tire 1 includes: a cylindrical annular structure 10; a rubber layer 11 which will become a tread part, provided along a circumferential direction of the annular structure on an outer side of the annular structure 10; a carcass part 12 provided on at least both sides in a width direction of the cylindrical structure 2 including the annular structure 10 and the rubber layer 11; and an extending part 10E that extends from both sides in the width direction of the annular structure 10 farther outward in the width direction than a ground contact edge CT on the outer side in the width direction of the tread part, and that is provided in plurality on both sides in the width direction along the circumferential direction of the annular structure 10.

Description

  The present invention relates to a pneumatic tire.

  Reducing the rolling resistance of a pneumatic tire is useful for improving the fuel efficiency of an automobile. In order to reduce the rolling resistance of a tire, for example, there is a technique of applying a rubber compounded with silica to a tread.

Akimasa Doi, “Recent Technology Trends in Tires”, Journal of Japan Rubber Association, September 1998, Vol. 71, p. 588-594

  The technique for reducing the rolling resistance of a pneumatic tire described in Non-Patent Document 1 is to improve the material. However, the rolling resistance is reduced by changing the structure of the pneumatic tire, and the steering stability is improved. There is also a possibility that the performance can be improved. An object of this invention is to provide the structure which can improve steering stability while reducing the rolling resistance of a pneumatic tire.

  The present invention has a cylindrical annular structure, a rubber layer provided on the outer side of the annular structure along the circumferential direction of the annular structure and serving as a tread portion, and a fiber coated with rubber. A carcass portion provided at least on both sides in the width direction of the cylindrical structure including the annular structure and the rubber layer, and a grounding end on the outer side in the width direction of the tread portion from both sides in the width direction of the annular structure. And a plurality of extending portions provided on both sides in the width direction toward the circumferential direction of the annular structure.

  In this invention, it is preferable that the said extension part is arrange | positioned along a part of said carcass part in a meridian cross section.

  In the present invention, the pneumatic tire has a pair of bead portions including a pair of bead wires and a bead filler disposed on the radially outer side of the bead portion at a portion that is radially inward and attached to a wheel rim. And it is preferable that the said extension part is return | folded in the width direction outer side of the said bead wire, and is extended to the width direction inner side of the said bead filler.

  In the present invention, it is preferable that the extension portion has a circumferential dimension at a position in contact with the annular structure that is a value obtained by dividing the circumferential dimension of the annular structure by 800 or more and 30 or less.

  In the present invention, it is preferable that the annular structure is embedded in the rubber layer and is not exposed to the surface on the radially outer side of the rubber layer.

  In the present invention, it is preferable that the outer side of the rubber layer and the outer side of the annular structure are parallel to the central axis except for a groove portion of the rubber layer.

  ADVANTAGE OF THE INVENTION This invention can provide the structure which can improve steering stability while reducing the rolling resistance of a pneumatic tire.

FIG. 1 is a meridional sectional view of a tire according to this embodiment. FIG. 2 is a perspective view of an annular structure included in the tire according to the present embodiment. FIG. 3 is a plan view of an annular structure included in the tire according to the present embodiment. FIG. 4 is an enlarged view of a carcass portion included in the tire according to the present embodiment. FIG. 5 is a meridional sectional view of the annular structure and the rubber layer. FIG. 6 is a meridional sectional view of a tire according to a modification of the present embodiment. FIG. 7 is a plan view of an annular structure having an extending portion according to a modification of the present embodiment. FIG. 8 is a plan view of an annular structure having an extending portion according to a modification of the present embodiment. FIG. 9 is a plan view of an annular structure having an extending portion according to a modification of the present embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that are equivalent. Furthermore, the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of components can be made without departing from the scope of the present embodiment.

  In order to reduce the rolling resistance of a pneumatic tire (hereinafter referred to as a tire if necessary), if the eccentric deformation of the tire is increased to the limit, the contact area between the tire and the road surface is reduced and the contact pressure is increased. As a result, the viscoelastic energy loss due to the deformation of the tread portion increases, and the rolling resistance increases. The present inventors paid attention to this point, and tried to reduce rolling resistance and improve operability by ensuring a contact area between the tire and the road surface and maintaining eccentric deformation. Eccentric deformation is a deformation in a primary mode in which a tire tread ring (crown region) is displaced vertically while maintaining a circular shape. In order to secure a contact area between the tire and the road surface and maintain eccentric deformation, the tire according to the present embodiment is, for example, outside the cylindrical annular structure manufactured by a thin metal plate. A rubber layer is provided in the circumferential direction, and the rubber layer is installed as a tread portion.

  FIG. 1 is a meridional sectional view of a tire according to this embodiment. FIG. 2 is a perspective view of an annular structure included in the tire according to the present embodiment. FIG. 3 is a plan view of an annular structure included in the tire according to the present embodiment. As shown in FIG. 1, the tire 1 is an annular structure. An axis passing through the center of the annular structure is a central axis (Y axis) of the tire 1. The tire 1 is filled with air when in use.

  The tire 1 rotates about a central axis (Y axis) as a rotation axis. The Y axis is a central axis and a rotation axis of the tire 1. An axis that is orthogonal to the Y axis that is the central axis (rotation axis) of the tire 1 and that is parallel to the road surface on which the tire 1 contacts the ground is an X axis, and an axis that is orthogonal to the Y axis and the X axis is a Z axis. The direction parallel to the Y axis is the width direction of the tire 1. A direction passing through the Y axis and perpendicular to the Y axis is the radial direction of the tire 1. Further, the circumferential direction around the Y axis is the circumferential direction of the pneumatic tire 1 (the direction indicated by the arrow CR in FIG. 1).

  As shown in FIG. 1, the tire 1 includes a cylindrical annular structure 10, a rubber layer 11, and a carcass portion 12. The annular structure 10 is a cylindrical member. The rubber layer 11 becomes a tread portion of the tire 1 by being provided on the surface 10so on the radially outer side of the annular structure 10 toward the circumferential direction of the annular structure 10. As shown in FIG. 3, the carcass portion 12 includes fibers 12F covered with rubber 12R. In the present embodiment, as shown in FIG. 1, the carcass portion 12 passes between the bead portions 13 through the radially inner side of the annular structure 10. That is, the carcass part 12 is continuous between both bead parts 13 and 13. The carcass portion 12 may be provided on both sides in the width direction of the annular structure 10 and may not be continuous between both bead portions 13 and 13. Thus, as shown in FIG. 2, the carcass portion 12 has a direction (that is, a width direction) parallel to the central axis (Y-axis) of the cylindrical structure 2 including at least the annular structure 10 and the rubber layer 11. As long as it is provided on both sides.

  In the tire 1, in the meridional section of the structure 2, the outer side 11 so (tread surface of the tire 1) of the rubber layer 11 and the surface 10 so on the outer side in the radial direction of the annular structure 10 are grooves S formed on the tread surface. It is more preferable that the shape is the same except for the portion and is parallel (including tolerance and error).

The annular structure 10 shown in FIGS. 2 and 3 is a metal structure. That is, the annular structure 10 is made of a metal material. Metallic material used for the annular structure 10 has a tensile preferably strength is 450 N / ^{m 2} or more 2500N / ^{m 2} or less, more preferably 600N / ^{m 2} or more 2400 N / ^{m 2} or less, more, 800 N / M ² or more and 2300 N / m ² or less is preferable. If the tensile strength is in such a range, the annular structure 10 can ensure sufficient strength and rigidity and can secure necessary toughness. The metal material that can be used for the annular structure 10 may be in the range described above for the tensile strength, but is preferably spring steel, high-tensile steel, stainless steel, or titanium (including titanium alloy). Of these, stainless steel is preferable because it has high corrosion resistance and easily obtains the above-described tensile strength range.

  The product of the tensile strength (MPa) and the thickness (mm) of the annular structure 10 is used as a pressure resistance parameter. The pressure resistance parameter is a parameter that is a measure of the resistance to the internal pressure of a gas (for example, air or nitrogen) filled in the tire 1. The withstand voltage parameter is preferably 200 or more and 1700 or less, and 250 or more and 1600 or less. If it is this range, the upper limit of the use pressure of the tire 1 can be ensured, and safety | security can fully be ensured. Moreover, if it is the said range, since the thickness of the cyclic structure 10 is not increased and it is not necessary to use a material with high breaking strength, it is suitable for mass production. Since it is not necessary to increase the thickness of the annular structure 10, the annular structure 10 can ensure the durability of repeated bending. Moreover, since it is not necessary to use a material with high breaking strength, the annular structure 10 and the tire 1 can be manufactured at low cost. As a passenger vehicle tire (PC tire), the pressure resistance parameter is preferably 200 or more and 1000 or less, and more preferably 250 or more and 950 or less. As a light truck tire (LT tire), the pressure resistance parameter is preferably 300 or more and 1200 or less, and more preferably 350 or more and 1100 or less. As a truck / bus tire (TB tire), the pressure resistance parameter is preferably 500 or more and 1700 or less, and more preferably 600 or more and 1600 or less.

  When manufacturing the annular structure 10 with stainless steel, use martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic / ferritic duplex stainless steel, precipitation hardening stainless steel in the classification of JIS G4303. Is preferred. By using these stainless steels, the annular structure 10 having excellent tensile strength and toughness can be obtained. Moreover, it is more preferable to use precipitation hardening stainless steel (SUS631, SUS632J1) among the stainless steels described above.

  The annular structure 10 may have a plurality of through holes that penetrate the inner peripheral surface and the outer periphery. A rubber layer 11 is attached to at least one of the radially outer side and the radially inner side of the annular structure 10. The rubber layer 11 is attached to the annular structure by chemical bonding with the annular structure 10. The through hole has an effect of strengthening physical coupling between the annular structure 10 and the rubber layer 11. For this reason, since the cyclic structure 10 having the through hole has improved bonding strength with the rubber layer 11 due to chemical and physical action (anchor effect), the annular structure 10 is securely fixed to the rubber layer 11. As a result, the durability of the tire 1 is improved.

The cross-sectional area of the through hole is preferably 0.1 mm ² or more and 100 mm ² or less, more preferably 0.12 mm ² or more and 80 mm ² or less, and further preferably 0.15 mm ² or more and 70 mm ² or less. If it is such a range, the unevenness | corrugation of the carcass part 12 can be suppressed, and the coupling | bonding by adhesion | attachment, ie, a chemical coupling | bonding, can fully be utilized. Furthermore, if it is the range mentioned above, the physical effect mentioned above, ie, an anchor effect, will occur most effectively. By these actions, the bond between the annular structure 10 and the rubber layer 11 can be strengthened.

  When the annular structure 10 has a through hole, the shape is not limited, but a circular shape or an elliptical shape is preferable. The through hole preferably has an equivalent diameter of 4 × A / C (C is the circumferential length of the through hole and A is the opening area of the through hole) of 0.5 mm to 10 mm. The through hole has a circular shape and a diameter of 1.0 mm or more and 8.0 mm or less is more preferable. Within such a range, physical and chemical bonds can be used effectively, so that the annular structure 10 and the rubber layer 11 are more firmly bonded. As will be described later, the equivalent diameters or diameters of the through holes may not all be the same.

  The total area of the through holes is preferably 0.5% or more and 30%, more preferably 1.0% or more and 20% or less, and still more preferably 1.5%, with respect to the surface area on the radially outer side of the annular structure 10. It is 15% or less. If it is such a range, the intensity | strength of the cyclic structure 10 is securable, utilizing a physical and chemical coupling | bonding effectively. As a result, the annular structure 10 and the rubber layer 11 are more firmly bonded, and the rigidity necessary for the annular structure 10 can be ensured. The intervals between the through holes may be unequal intervals or may be equal intervals. By doing in this way, the contact shape of the tire 1 can also be controlled.

  As shown in FIGS. 1, 2, and 3, the annular structure 10 extends from both sides in the width direction to the outer side in the width direction than the ground contact end CT on the outer side in the width direction of the tread portion (rubber layer 11), and A plurality of extending portions 10E provided on both sides in the width direction toward the circumferential direction of the annular structure 10 are included. In the tire 1 using the annular structure 10 in which a thin plate of metal or the like has a cylindrical shape, rolling resistance is reduced. However, since the rigidity of the tread portion is increased, the balance between the rigidity of the side portion SP and the bead portion 13 is lost, and as a result, the steering stability may be lowered. In the tire 1, since the annular structure 10 has the extending portion 10 </ b> E, it is possible to suppress a sudden change in rigidity between the tread portion and the side portion SP, and to make an appropriate rigidity balance of the tire 1. Can do. Moreover, since the tire 1 has the extending portion 10E, the rigidity, particularly the rigidity of the side portion can be improved. As a result, the steering stability of the vehicle equipped with the tire 1 is improved. 3, the dimension L in the circumferential direction (direction shown by arrow C in FIG. 4) and the dimension WB and the array pitch P in the width direction (direction shown by arrow Y in FIG. 4) of each extending portion 10E shown in FIG. By changing at least one of the shapes, the rigidity of the tire 1 can be adjusted and the performance of the tire 1 can be adjusted. The extending part 10E may be embedded in the side part SP (configured with two layers).

  As shown in FIG. 1, the extending portion 10 </ b> E is disposed along a part of the carcass portion 12 in the meridional section. At this time, it is preferable that the extending portion 10E is in contact with the carcass portion 12 that generates spring characteristics in the longitudinal direction, the lateral direction, the circumferential direction, and the torsional direction in the side portion SP of the tire 1 and handles rigidity. Such a structure is preferable for improving the rigidity of the tire 1.

  In the extending portion 10E, the circumferential dimension Lc or the array pitch P at the position in contact with the annular structure 10 is preferably not less than a value obtained by dividing the circumferential dimension of the annular structure 10 by 800 and not more than 30. . By setting the range of such division, the rigidity of the tire 1 can be secured and the deformation of the tire 1 can be followed, and the shape when the annular structure 10 is deformed becomes closer to a circle from a polygon. The uniformity of the tire 1 can be secured. The circumferential dimension Lc at the position in contact with the annular structure 10 is more preferably not less than a value obtained by dividing 200 and not more than a value obtained by dividing 60. In this way, the rigidity of the tire 1 can be further improved and the uniformity can be ensured. The arrangement pitch P of the extending portions 10E is an interval at which the plurality of extending portions 10E are arranged in the circumferential direction, and is a distance between adjacent extending portions 10E. The arrangement pitch P is measured between the centers of the dimension L in the circumferential direction of the extending portion 10E in a state where the annular structure 10 is expanded.

  The annular structure 10 is a rectangular plate having a plurality of extending portions 10E on the long side, or a rectangular shape having a plurality of extending portions 10E on the long side, and a plurality of through holes. It can be manufactured by abutting and welding the short side 10T throws of the perforated plate material. In this way, the annular structure 10 can be manufactured relatively easily. Moreover, the manufacturing method of the cyclic structure 10 is not limited to this. For example, the annular structure 10 may be manufactured by forming a plurality of holes in the outer periphery of the cylinder and then scraping the inside of the cylinder.

  The surface 10so on the radially outer side of the annular structure 10 and the inner side 11si of the rubber layer 11 are in contact with each other. In the present embodiment, the annular structure 10 and the rubber layer 11 are fixed by, for example, an adhesive. With such a structure, force can be transmitted between the annular structure 10 and the rubber layer 11. The means for fixing the annular structure 10 and the rubber layer 11 is not limited to the adhesive. Moreover, it is preferable that the annular structure 10 is not exposed to the outside in the radial direction of the rubber layer. In this way, it is possible to suppress adhesion peeling at the interface between the rubber layer 11 and the annular structure 10 and more reliably fix the annular structure 10 and the rubber layer 11. Further, the annular structure 10 may be embedded in the rubber layer 11. Even if it does in this way, the annular structure 10 and the rubber layer 11 can be fixed more reliably.

The rubber layer 11 includes synthetic rubber, natural rubber, or a rubber material in which these are mixed, and carbon, SiO _2, or the like added as a reinforcing material to the rubber material. The rubber layer 11 is an endless belt-like structure. As shown in FIG. 1, in this embodiment, the rubber layer 11 has a plurality of grooves (main grooves) S on the outer side 11so. The rubber layer 11 may have lug grooves in addition to the grooves S.

  FIG. 4 is an enlarged view of a carcass portion included in the tire according to the present embodiment. The carcass portion 12 is a strength member that serves as a pressure vessel together with the annular structure 10 when the tire 1 is filled with air. The carcass portion 12 and the annular structure 10 support the load acting on the tire 1 by the internal pressure of the air filled therein, and withstand the dynamic load that the tire 1 receives during traveling. In the present embodiment, the carcass portion 12 of the tire 1 has an inner liner 14 on the inner side. The inner liner 14 suppresses leakage of air filled in the tire 1. Both carcass portions 12 each have a bead portion 13 on the radially inner side. The bead portion 13 is fitted to a wheel rim to which the tire 1 is attached. The carcass portion 12 may be mechanically coupled to the wheel rim.

  FIG. 5 is a meridional sectional view of the annular structure and the rubber layer. The elastic modulus of the annular structure 10 is preferably 70 GPa or more and 250 GPa or less, and more preferably 80 GPa or more and 230 GPa or less. Also. The thickness tm of the annular structure 10 is preferably 0.1 mm or more and 0.8 mm or less. Within this range, it is possible to ensure the durability of repeated bending while ensuring the pressure resistance performance. The product of the elastic modulus and the thickness tm (referred to as a stiffness parameter) of the annular structure 10 is preferably 10 or more and 500 or less, and more preferably 15 or more and 400 or less.

  By setting the stiffness parameter in the above range, the annular structure 10 has a greater stiffness in the meridional section. For this reason, when the tire 1 is filled with air and when the tire 1 contacts the road surface, the annular structure 10 suppresses deformation in the meridional section of the rubber layer 11 serving as a tread portion. As a result, the tire 1 is suppressed from loss of viscoelastic energy due to the deformation. Moreover, the rigidity in the radial direction of the annular structure 10 is reduced by setting the rigidity parameter within the above range. For this reason, the tread portion of the tire 1 is flexibly deformed at the contact portion with the road surface, similarly to the conventional pneumatic tire. With such a function, the tire 1 is eccentrically deformed while avoiding local strain and stress concentration in the ground contact portion, so that the strain in the ground contact portion can be dispersed. As a result, in the tire 1, local deformation of the rubber layer 11 in the ground contact portion is suppressed, so that a ground contact area is ensured and rolling resistance is reduced.

  Furthermore, since the tire 1 has a large in-plane rigidity of the annular structure 10 and can secure the contact area of the rubber layer 11, the contact length in the circumferential direction can be ensured. For this reason, the lateral force generated when the steering angle is input to the tire 1 increases. As a result, the tire 1 can obtain a large cornering power. Further, when the annular structure 10 is made of metal, the air filled in the tire 1 hardly penetrates the annular structure 10. As a result, there is an advantage that the air pressure of the tire 1 can be easily managed. For this reason, it is possible to suppress a decrease in the air pressure of the tire 1 even for a usage mode in which the tire 1 is not filled with air for a long period.

  The distance tr (the thickness of the rubber layer 11) between the surface 10so on the radially outer side of the annular structure 10 and the outer side 11so of the rubber layer 11 is preferably 3 mm or more and 20 mm or less. By setting the distance tr in such a range, it is possible to suppress excessive deformation of the rubber layer 11 during cornering while ensuring the ride comfort. The dimension (annular structure width) WB of the annular structure 10 in the direction parallel to the central axis (Y-axis) of the annular structure 10, that is, the width direction, that is, the dimension of the portion not including the extending portion 10E is shown in FIG. The total width of the tire 1 in a direction parallel to the central axis (Y-axis) shown in FIG. 5 (a state where it is assembled on a wheel with a JATMA prescribed rim width and filled with 300 kPa of air) W is 50% (W × 0.5) or more and 95% (W × 0.95) or less is preferable. When WB is smaller than W × 0.5, the rigidity in the meridional section of the annular structure 10 is insufficient, and as a result, the region for maintaining the eccentric deformation with respect to the tire width decreases. As a result, the effect of reducing the rolling resistance and the cornering power may be reduced. Further, when WB exceeds W × 0.95, the tread portion may buckle and deform the annular structure 10 in the central axis (Y-axis) direction at the time of ground contact, and the annular structure 10 may be deformed. By setting W × 0.5 ≦ WB ≦ W × 0.95, it is possible to maintain cornering power while reducing rolling resistance, and to suppress deformation of the annular structure 10.

  The length between the ends of both extending portions 10E and 10E in the tire width direction (the length of WE + WB + WE in FIG. 3) is preferably 105% or more and 200% or less of the contact width of the tire 1, and is 105% or more and 2005. The following is more preferable. In this case, the ground contact width of the tire 1 is measured in a state where the tire 1 is loaded with the maximum load at 200 kPa in the air pressure-load capability correspondence table defined in JATMA in a state where the air pressure is 200 kPa.

  In the meridional section shown in FIG. 1, the tire 1 has an outer surface 11 so of the rubber layer 11, that is, a profile of the tread surface, which has the same shape as the surface 10 so on the radially outer side of the annular structure 10 except for the groove S portion. It is preferable. With such a structure, when the tire 1 is grounded or rolled, the rubber layer 11 serving as the tread portion and the annular structure 10 are deformed in substantially the same manner. As a result, the tire 1 is less deformed by the rubber layer 11, so that the loss of viscoelastic energy is smaller and the rolling resistance is also smaller.

  If the outer side 11so of the rubber layer 11 and the surface 10so on the outer side in the radial direction of the annular structure 10 protrude toward the outer side in the radial direction of the tire 1 or protrude toward the inner side in the radial direction, The pressure distribution is non-uniform. As a result, local strain and stress concentration occur in the grounding portion, and the rubber layer 11 may be locally deformed in the grounding portion. In the present embodiment, as shown in FIG. 3, in the tire 1, the outer side 11 so (tread surface of the tire 1) of the rubber layer 11 and the surface 10 so on the radially outer side of the annular structure 10 have the same shape (preferably It is preferable that the rubber layer 11 and the annular structure 10 (that is, the structure 2) are parallel to the central axis (Y axis) (including tolerance and error). With such a structure, the ground contact portion of the tire 1 can be made substantially flat. Since the tire 1 has a uniform pressure distribution in the contact portion, local distortion and stress concentration in the contact portion are suppressed, and local deformation of the rubber layer 11 in the contact portion is suppressed. As a result, since the loss of viscoelastic energy is reduced, the rolling resistance of the tire 1 is also reduced. Moreover, since local deformation | transformation of the rubber layer 11 in a contact part is suppressed, a tire can ensure a ground contact area and can ensure the contact length of the circumferential direction simultaneously. For this reason, the tire 1 can also ensure cornering power.

  In the present embodiment, the shape of the rubber layer 11 in the meridional section is such that the outer side 11so of the rubber layer 11 and the surface 10so on the radially outer side of the annular structure 10 are parallel to these central axes (Y-axis). The shape is not particularly limited. For example, the shape of the rubber layer 11 in the meridional section may be a trapezoid or a parallelogram. When the shape of the rubber layer 11 in the meridional section is a trapezoid, either the upper base or the lower base of the trapezoid may be the outer side 11so of the rubber layer 11. In any case, only the portion of the annular structure 10 may be parallel to the tread surface profile (excluding the groove portion) of the tire 1. Next, the shape of the tread surface of the tire 1 will be described in more detail.

  FIG. 6 is a meridional sectional view of a tire according to a modification of the present embodiment. This tire 1A has a pair of bead portions 13 including a pair of bead wires 13W and a bead filler 13F disposed on the radially outer side of the bead portion 13 in a portion attached to the rim of the wheel in the radial direction, The extending portion 10E is folded back on the outer side in the width direction of the bead wire 13W and extends to the inner side in the width direction of the bead filler 13F. By doing in this way, since the extension part 10E is fixed more firmly by the bead wire 13W and the bead filler 13F, and these outer rubber | gum, the rigidity of the tire 1 further improves. In addition, the extension part 10E can obtain the effect of improving the rigidity if the end part is disposed at least on the radially inner side of the bead wire 13W.

  7 to 9 are plan views of an annular structure having an extending portion according to a modification of the present embodiment. The annular structure 10a shown in FIG. 7 is the same structure as the annular structure 10 shown in FIG. 3, except that the shape of the extending portion 10Ea is smaller in the circumferential direction toward the outer side in the width direction. Is different. That is, the extending portion 10Ea included in the annular structure 10a has a triangular shape, and one vertex is directed outward in the width direction. The annular structure 10a is manufactured by abutting and welding the short sides 10Ta. Like the annular structure 10a, when the dimensions of the extending portion 10Ea in the circumferential direction are reduced toward the outer side in the width direction, the adjacent extending portions 10Ea are connected when the short sides 10Ta are connected to form a cylindrical shape. Interference on the outer side in the width direction can be avoided.

  An annular structure 10b shown in FIG. 8 has the same structure as that of the annular structure 10a shown in FIG. 7. However, in the connection part between the plurality of extending parts 10Eb and the annular structure 10b, adjacent extending parts 10Eb The difference is that they are arranged without gaps. In this way, since the number of the extending portions 10Eb can be increased, if the annular structure 10b is used for the tires 1 and 1A, the rigidity of the tires 1 and 1A can be further increased. The annular structure 10c shown in FIG. 9 has the same structure as the annular structure 10b shown in FIG. 8, but the width direction outside of the extending part 10Ec and the connection part between the plurality of extending parts 10Ec and the annular structure 10c. The point is that it has an arc shape. By doing in this way, the crack to the rubber | gum which contacts the part of the width direction outer side of the extension part 10Ec is suppressed, or the stress concentration of the connection part of several extension part 10Ec and the cyclic structure 10c is reduced. can do. As a result, if the annular structure 10c is used for the tires 1 and 1A, the durability of the tires 1 and 1A can be further improved.

DESCRIPTION OF SYMBOLS 1, 1A Tire 2 Structure 10, 10a, 10b, 10c Annular structure 10E, 10Ea, 10Eb, 10Ec Extension part 11 Rubber layer 12 Carcass part 13 Bead part 13F Bead filler 13W Bead wire

Claims (6)

A cylindrical annular structure;
A rubber layer provided on the outside of the annular structure along the circumferential direction of the annular structure and serving as a tread portion;
Carcass portions having fibers coated with rubber and provided at least on both sides in the width direction of the cylindrical structure including the annular structure and the rubber layer;
Extending from the both sides in the width direction of the annular structure to the outside in the width direction with respect to the grounding end on the outside in the width direction of the tread portion, and a plurality of extensions provided on both sides in the width direction toward the circumferential direction of the annular structure. And
A pneumatic tire characterized by including.   The pneumatic tire according to claim 1, wherein the extending portion is disposed along a part of the carcass portion in a meridional section. The pneumatic tire has a pair of bead portions including a pair of bead wires and a bead filler disposed on a radially outer side of the bead portion in a portion attached to a rim of the wheel in the radial direction;
The pneumatic tire according to claim 1, wherein the extending portion is folded back at the outer side in the width direction of the bead wire and extends to the inner side in the width direction of the bead filler.   The circumferential dimension of the extending portion at a position in contact with the annular structure is a value obtained by dividing the circumferential dimension of the annular structure by 800 or more and 30 or less. The pneumatic tire according to item 1.   The pneumatic tire according to any one of claims 1 to 4, wherein the annular structure is embedded in the rubber layer and is not exposed on a surface of the rubber layer on a radially outer side.   The pneumatic tire according to any one of claims 1 to 5, wherein an outer side of the rubber layer and an outer side of the annular structure are parallel to the central axis except for a groove portion of the rubber layer.

Images