Patent Publication Number: US-2021178819-A1

Title: Tire

Description:
TECHNICAL FIELD 
     The present disclosure relates to a tire provided with a belt layer that is structured by a cord wound in a helical shape. 
     BACKGROUND ART 
     Heretofore, tires have been proposed (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2016-193725) that are provided with a belt layer, known as a spiral belt, that is formed by winding a cord in a helical shape. 
     SUMMARY OF INVENTION 
     Technical Problem 
     The present inventors have conducted testing of tires and diverse investigations. As a result, the present inventors have discovered that, in a tire provided with a spiral belt layer structured by a cord wound in a helical shape, uniformity, and specifically radial force variation (RFV), is degraded as a result of length direction end portions of the cord being disposed at two belt width direction end portions of the spiral belt layer. 
     In consideration of the circumstances described above, an object of the present disclosure is to improve uniformity of a tire provided with a spiral belt layer that is structured with a cord wound in a helical shape. 
     Solution to Problem 
     A tire according to a first aspect includes: a spiral belt layer provided at an outer periphery side of a tire carcass member, the spiral belt layer being structured with a belt cord wound in a helical shape; and a ring-shaped band respectively disposed at a tire diameter direction outer side of each of an end portion of the spiral belt layer at one side in a tire width direction and an end portion of the spiral belt layer at the other side in the tire width direction, the band including a belt-shaped member that is wound at least one full circumference in a tire circumference direction. A region of the spiral belt layer in which a number of strands of the belt cord counted in the tire width direction is greater and a region in which the number is smaller are formed by one end portion and another end portion in the tire circumference direction of the belt cord being disposed at different positions in the tire circumference direction, and the band is specified with an overlap portion at which a number of layers of the belt-shaped member is greater than in another region of the band in the circumference direction, the overlap portion being provided at the region in which the number of strands of the belt cord is smaller. 
     Because the spiral belt layer is structured by winding of the cord in the helical shape, the end portions of the cord are disposed at one side and the other side in a belt width direction. Therefore, when the one end portion and the other end portion of the belt cord of the spiral belt layer are at different positions in the tire circumference direction, the region in which the number of strands of the belt cord counted in the tire width direction is smaller and the region in which the same number is greater are formed in the spiral belt layer. In other words, a region in which the belt width is greater and a region in which the belt width is smaller are formed in the spiral belt layer. Consequently, tire circumference direction bending stiffness is higher in the region in which the belt width is greater than in the region in which the belt width is smaller. As a result, uniformity, specifically RFV, of the tire provided with the spiral belt layer is degraded. 
     At the overlap of each band of the tire according to the first aspect, the number of layers of the belt-shaped member is larger than in the another region in the circumference direction, and the tire circumference direction bending stiffness is relatively higher than in the another region in the circumference direction. In the tire according to the first aspect, the width direction end portions of the spiral belt layer in which the end portions of the belt cord are disposed are covered by the bands, and the overlap portions of the bands are disposed in the region of the spiral belt layer in which the number of strands of the belt cord counted in the tire width direction is smaller. Thus, the tire circumference direction bending stiffness of a layer including the spiral belt layer and the bands may be made more uniform in the tire circumference direction, and the RFV may be improved compared to a structure without the bands. 
     In other words, because the overlap portions of the bands are disposed as described above, an RFV reaction force of the spiral belt layer may be raised in a region of the spiral belt layer in which the reaction force is small (a valley portion), and the RFV may be improved. 
     Advantageous Effects of Invention 
     According to the present disclosure, an excellent effect is provided in that uniformity may be improved in a tire provided with a spiral belt layer that is structured with a cord wound in a helical shape. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional diagram showing a tire according to a first exemplary embodiment of the present invention, which shows a state in which the tire is cut along a tire turning axis. 
         FIG. 2  is a plan view showing positional relationships of a spiral belt layer and bands. 
         FIG. 3  is an exploded perspective view showing the spiral belt layer and the bands. 
         FIG. 4  is a sectional diagram showing a tire according to a second exemplary embodiment of the present invention, which shows a state in which the tire is cut along the tire turning axis. 
         FIG. 5  is a tire exploded perspective view showing the tire according to the second exemplary embodiment of the present invention. 
         FIG. 6  is a graph showing an RFV curve of a tire 2 in which no band is provided. 
         FIG. 7  is a graph showing an RFV curve of a tire 1 in which bands are provided. 
         FIG. 8A  is a perspective view showing a spiral belt layer of a tire according to an alternative example. 
         FIG. 8B  is a graph showing an RFV curve of the same tire. 
         FIG. 9A  is a perspective view showing a spiral belt layer of a tire according to a further alternative example. 
         FIG. 9B  is a graph showing an RFV curve of the same tire. 
         FIG. 10  is a side view, seen along a tire turning axis, showing a band of a tire according to an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     First Exemplary Embodiment 
     A tire  10  according to a first exemplary embodiment of the present invention is described in accordance with  FIG. 1  to  FIG. 3 . 
     —Tire Carcass Member— 
     As shown in  FIG. 1 , the tire  10  is, for example, a tire for use on an automobile. The tire  10  is provided with a tire carcass member  12 . The tire carcass member  12  is fabricated of resin material. The tire carcass member  12  includes a bead portion  16 , a side portion  18  that extends to a tire radius direction outer side of the bead portion  16 , and a crown portion  26  that extends to a tire width direction inner side of the side portion  18 . A tread  32  is disposed at the crown portion  26 . The term “bead portion  16 ” as used herein is intended to include 30% of a tire sectional height of the tire carcass member  12  from the tire diameter direction inner side of the tire carcass member  12 . The tire carcass member  12  is formed in a toroidal shape centered on a tire turning axis. As a resin material constituting the tire carcass member  12 , thermoplastic resins (including thermoplastic elastomers), thermosetting resins and other general purpose resins may be mentioned, as well as engineering plastics (including super engineering plastics) and the like. The meaning of the term “resin material” as used herein is not intended to include vulcanized rubbers. 
     The meaning of the term “thermoplastic resin” (including thermoplastic elastomers) is intended to include polymer compounds of which the material softens and flows with a rise in temperature, and goes into a relatively hard and strong state when cooled. The present specification distinguishes between: polymer compounds of which the material softens and flows with a rise in temperature, goes into a relatively stiff and strong state when cooled, and features rubber-like resilience, which are referred to as thermoplastic elastomers; and polymer compounds of which the material softens and flows with a rise in temperature, goes into a relatively hard and strong state when cooled, and does not feature rubber-like resilience, which are referred to as thermoplastic resins that are not elastomers. 
     As a thermoplastic resin (which may be a thermoplastic elastomer), polyolefin-based thermoplastic elastomers (TPO), polystyrene-based thermoplastic elastomers (TPS), polyamide-based thermoplastic elastomers (TPA), polyurethane-based thermoplastic elastomers (TPU), polyester-based thermoplastic elastomers (TPC), dynamically vulcanized thermoplastic elastomers (TPV) and the like may be mentioned, and also polyolefin-based thermoplastic resins, polystyrene-based thermoplastic resins, polyamide-based thermoplastic resins and polyester-based thermoplastic resins and the like. 
     An above-mentioned thermoplastic resin material that may be employed has, for example, a deflection temperature under load as defined in ISO 75-2 or ASTM D648 (0.45 MPa load) of at least 78° C., a tensile yield strength as defined in JIS K7113 of at least 10 MPa, a tensile elongation at break as defined in JIS K7113 of at least 50%, and a Vicat softening temperature as defined in JIS K7206 (method A) of 130° C. 
     The meaning of the term “thermoplastic resins” is intended to include polymer compounds that form a three-dimensional mesh structure in association with a temperature rise and harden. As thermoplastic resins, for example, phenol resins, epoxy resins, melamine resins, urea resins and the like may be mentioned. 
     A resin material that is used may be a previously known thermoplastic resin (which may be a thermoplastic elastomer) or thermosetting resin, and may be a general purpose resin such as a (meth)acrylic resin, an EVA resin, a vinyl chloride resin, a fluorine-based resin, a silicone-based resin or the like. 
     A bead core  22  is embedded in the bead portion  16 . A thermoplastic material constituting the bead core  22  is preferably an olefin-based, ester-based, amide-based or urethane-based TPE, or a TPV in which a portion of a rubber-based resin is mixed. An above-mentioned thermoplastic resin material preferably has, for example, a deflection temperature under load as defined in ISO 75-2 or ASTM D648 (0.45 MPa load) of at least 75° C., a tensile yield elongation again as defined in JIS K7113 of at least 10%, a tensile elongation at break again as defined in JIS K7113 of at least 50%, and a Vicat softening temperature as defined in JIS K7113 (method A) of at least 130° C. 
     The bead core  22  has a toroidal shape and is formed of a thermoplastic material with a higher modulus of elasticity than the resin material of the tire carcass member  12 . The modulus of elasticity of the bead core  22  is preferably at least 1.5 times the modulus of elasticity of the tire carcass member  12 , and is more preferably at least 2.5 times the same. If the ratio of the modulus of elasticity is less than 1.5 times, then when the tire  10  is mounted to a rim  24  and filled with air, and the internal pressure of the tire  10  is raised, it is conceivable that the bead portion  16  will be lifted to the tire radius direction outer side and detach from the rim  24 . The bead core  22  may employ a hard resin and be formed by insert-molding (extrusion-molding) or the like; a method of formation of the bead core  22  is not particularly limited. 
     The bead core  22  may be formed in a shape that includes waves in the tire circumference direction, such that a bead core radius varies with tire circumference direction position. In this case, the bead core  22  itself may be extensible to some extent. Thus, rim assembly is easier. The bead core  22  is not limited to resins (thermoplastic materials) and may be formed by bundling resin-coated steel cords with helical shapes in the tire circumference direction. 
     —Spiral Belt Layer— 
     As shown in  FIG. 1  and  FIG. 2 , a spiral belt layer  28  is provided at an outer periphery of the crown portion  26  of the tire carcass member  12 . The spiral belt layer  28  is formed by winding a resin-coated cord  28 C in the tire circumference direction into a helical shape. The resin-coated cord  28 C is an example of a belt cord with a belt shape in which, for example, two cords  28 B that are arrayed in parallel with one another are coated with a resin  28 A. The spiral belt layer  28  covers substantially the whole of the crown portion  26 . Steel cords are employed for the cords  28 B according to the present exemplary embodiment, but cords other than steel cords may be employed, such as organic fibers or the like. 
     Accordingly, an end portion  28 Ce 1  at one side of the resin-coated cord  28 C is disposed at one side of the spiral belt layer  28  in the width direction (for example, the left side in the drawings), and an end portion  28 Ce 2  at the other side of the resin-coated cord  28 C is disposed at the other side of the spiral belt layer  28  in the width direction (for example, the right side in the drawings). 
     As shown in  FIG. 3 , in the spiral belt layer  28  according to the present exemplary embodiment, a circumference direction position of the end portion  28 Ce 1  at the length direction one side of the resin-coated cord  28 C and a circumference direction position of the end portion  28 Ce 2  at the length direction other side of the resin-coated cord  28 C are disposed to be offset by 22° in the circumference direction. In the spiral belt layer  28  according to the present exemplary embodiment, as an example, the end portion  28 Ce 1  of the resin-coated cord  28 C is wound on first and the end portion  28 Ce 2  is wound on last. However, the end portion  28 Ce 2  may be wound on first and the end portion  28 Ce 1  may be wound on last. In the present exemplary embodiment, the resin-coated cord  28 C is wound in a clockwise direction, but may be wound in the counterclockwise direction. 
     In the spiral belt layer  28  according to the present exemplary embodiment, the circumference direction position of the end portion  28 Ce 1  at the one side of the resin-coated cord  28 C and the circumference direction position of the end portion  28 Ce 2  at the other side of the resin-coated cord  28 C are arranged to be offset by 22° in the circumference direction. In other words, if the end portion  28 Ce 1  that is the start of winding of the resin-coated cord  28 C is represented as an origin (0°), the end portion  28 Ce 2  that is the end of winding is disposed at 220° in the clockwise direction. 
     In the spiral belt layer  28  according to the present exemplary embodiment, a region of the resin-coated cord  28 C in the circumference direction from the end portion  28 Ce 1  that is the start of winding to the end portion  28 Ce 2  that is the end of winding is referred to as an overlap region  28 D. 
     In the present exemplary embodiment, if the spiral belt layer  28  is viewed in the circumference direction and a number of strands of the resin-coated cord  28 C in the belt width direction is counted, the number is greater from the end portion  28 Ce 1  that is the start of winding of the resin-coated cord  28 C (the origin 0°) to the 22° position than the number in other regions. Thus, the belt width from the end portion  28 Ce 1  (the origin 0°) to the 22° position is wider than the belt width in the other regions. That is, when the tire circumference direction bending stiffness of the spiral belt layer  28  is considered along the tire circumference direction, the tire circumference direction bending stiffness is higher from the end portion  28 Ce 1  (the origin 0°) to the 22° position than the bending stiffness in the other regions of the circumference direction. 
     —Bands— 
     As shown in  FIG. 1  to  FIG. 3 , bands  30  are disposed at the tire diameter direction outer sides of the end portion at the width direction one side of the spiral belt layer  28  and the end portion at the width direction other side of the spiral belt layer  28 . 
     Each band  30  is formed by winding a belt-shaped member  30 A a little more than one turn (at least one full circumference) directly in the tire circumference direction. The belt-shaped member  30 A has a belt shape with a certain width, which includes plural fiber cords. The band  30  is provided with an overlap portion  30 B, that is, a multilayer portion, at a portion in the circumference direction. At the overlap portion  30 B, a portion at one side in the length direction of the belt-shaped member  30 A and a portion at the other side in the length direction are superposed with one another in the diameter direction. 
     The fiber cords that are employed in the band  30  may be, for example, organic fiber cords of nylon, polyester, an aromatic polyamide or the like. However, steel cords may be employed, and publicly known materials of layers that are employed in ordinary pneumatic tires may be employed. The band  30  according to the present exemplary embodiment includes plural fiber cords. However, for example, the band  30  may not include fibers but be formed of a sheet-shaped member of a single resin material or a single rubber. 
     It is preferable if a bending stiffness of the band  30  to follow deformation of the tread is not more than a bending stiffness of the spiral belt layer  28 . The cords of the band  30  may be covered with rubber or resin. 
     A width W 1  of the belt-shaped member  30 A constituting the band  30  is wider than a width W 2  of the resin-coated cord  28 C constituting the spiral belt layer  28 . 
     A length direction end portion of the belt-shaped member  30 A is cut orthogonally to the length direction of the belt-shaped member  30 A, but may be cut at an angle. 
     As shown in  FIG. 3 , the overlap portion  30 B of the band  30  according to the present exemplary embodiment is disposed at the opposite side of the tire rotation axis AR from the overlap region  28 D of the spiral belt layer  28  (disposed at the opposite side of the tire rotation axis AR from the end portion  28 Ce 1  at one side of the resin-coated cord  28 C and the end portion  28 Ce 2  at the other side). More specifically, treating the end portion  28 Ce 1  that is the start of winding of the resin-coated cord  28 C as the origin (0°), the overlap portion  30 B is in a range from a position 130° clockwise from the origin 0° to a position 170° further to clockwise (a position 300° from the origin 0°). 
     Therefore, in the band  30  according to the present exemplary embodiment, the tire circumference direction bending stiffness at the overlap portion  30 B at which the belt-shaped member  30 A is superposed is higher than the tire circumference direction bending stiffness in other regions in which the belt-shaped member  30 A is not superposed. 
     As shown in  FIG. 2 , the band  30  at one side covers the end portion  28 Ce 1  at the one side of the resin-coated cord  28 C and portions of the resin-coated cord  28 C near to the width direction inner side of the end portion  28 Ce 1 , and the band  30  at the other side covers the end portion  28 Ce 2  at the other side of the resin-coated cord  28 C and portions of the resin-coated cord  28 C near to the width direction inner side of the end portion  28 Ce 2 . 
     Each band  30  may be formed to be wider and provided so as to cover the resin-coated cord  28 C further to the width direction inner side. In the present exemplary embodiment, as an example, the width W 2  of the resin-coated cord  28 C is 5 mm and the width W 1  of each belt-shaped member  30 A is 12 mm. However, the width W 2  of the resin-coated cord  28 C is not limited to 5 mm, and the width W 1  of the belt-shaped member  30 A is not limited to 12 mm. 
     —Tread— 
     As shown in  FIG. 1 , the tread  32  is provided at the tire radius direction outer side of the crown portion  26  and the spiral belt layer  28 . The tread  32  is, for example, a pre-cured tread (PCT) that is formed using a rubber. The tread  32  is formed of a rubber with more excellent wear resistance than the resin material forming the tire carcass member  12 . As this rubber, a rubber of the same kind as a tread rubber used in ordinary conventional pneumatic tires that employ rubber as a resilient material may be used; for example, a styrene-butadiene rubber (SBR) may be used. The tread  32  that is employed may be constituted of an alternative kind of resin material with more excellent wear resistance than the resin material forming the tire carcass member  12 . In  FIG. 1 , drainage grooves of the tread  32  are not shown in the drawing, but conventional publicly known drainage grooves may be formed in the tread  32 . 
     —Reinforcement Layer— 
     A reinforcement layer  14  is disposed at an outer side face of the tire carcass member  12 . In the reinforcement layer  14 , plural cords (not shown in the drawings) are arranged in parallel with one another and are covered with a rubber material. The reinforcement layer  14  extends from the bead portion  16  to the side portion  18 . For example, a reinforcement layer  14  with a similar structure to a carcass ply employed in a conventional pneumatic tire fabricated of rubber may be employed. 
     Each cord of the reinforcement layer  14  is, for example, a twisted cord or an assembly of filaments. A material of the cords of the reinforcement layer  14  is, for example, an aliphatic polyamide, polyethylene terephthalate, glass, alamide, or a metal such as steel or the like. In the reinforcement layer  14  according to the present exemplary embodiment, the cords extend in the tire radius direction. However, the cords may extend in a direction that is angled relative to the tire radius direction. 
     The reinforcement layer  14  is secured at the bead core  22  embedded in the bead portion  16 . More specifically, a tire radius direction inner side end  14 A of the reinforcement layer  14  passes the tire diameter direction inner side of the bead core  22  and is disposed at a tire inner face side. 
     A tire radius direction outer side end  14 C of the reinforcement layer  14  reaches the spiral belt layer  28 , via the tire carcass member  12  from the bead portion  16  to the side portion  18  and extending to the crown portion  26 . The reinforcement layer  14  may extend as far as the tire width direction center. A position of the tire radius direction outer side end  14 C of the reinforcement layer  14  may terminate in a vicinity of a tire maximum width position of the side portion  18 , or may terminate before reaching the crown portion  26  (at a “buttress” portion). 
     The reinforcement layer  14  according to the present exemplary embodiment corresponds to a carcass layer in a conventional ordinary pneumatic tire fabricated of rubber. 
     A side rubber layer  40  is provided at a tire outer face  14 B side of the reinforcement layer  14 . The side rubber layer  40  may employ a rubber of the same type as a rubber that forms a sidewall in a conventional ordinary pneumatic tire that uses rubber as a resilient material. Further, the side rubber layer  40  may be a resin layer. 
     —Operation— 
     Below, operation and effects of the tire  10  according to the present exemplary embodiment are described. 
     The spiral belt layer  28  is formed by the resin-coated cord  28 C containing the cords  28 B being wound in a helical shape, the end portion  28 Ce 1  being disposed at one side of the spiral belt layer  28  in the belt width direction, and the end portion  28 Ce 2  being disposed at the other side of the spiral belt layer  28  in the belt width direction. Consequently, the spiral belt layer  28  does not have constant width in the tire width direction; a region of greater width and a region of smaller width are formed in the circumferential direction. Therefore, when the bending stiffness of the spiral belt layer  28  is considered along the circumference direction, the tire circumference direction bending stiffness of the overlap region  28 D is larger than the bending stiffness of other regions in the rest of the spiral belt layer  28 . When, for example, an RFV curve of a tire that is not provided with the bands  30  is considered, reaction forces (in the tire diameter direction) in regions close to the overlap region  28 D tend to be larger than in regions at the opposite side from the overlap region  28 D. 
     In the tire  10  according to the present exemplary embodiment, because the width direction end portions of the spiral belt layer  28  at which the end portions of the resin-coated cord  28 C are disposed are covered by the bands  30 , and the overlap portions  30 B of the bands  30  are disposed in a region of the spiral belt layer  28  with low bending stiffness, the tire circumference direction bending stiffness of a layer including the spiral belt layer  28  and the bands  30  may be made more uniform in the tire circumference direction. Thus, the RFV may be improved compared to a structure without the bands  30 . 
     Second Exemplary Embodiment 
     A tire  38  according to a second exemplary embodiment of the present invention is described in accordance with  FIG. 4  and  FIG. 5 . Structures that are the same as in the first exemplary embodiment are assigned the same reference symbols and are not described here. 
     As shown in  FIG. 4  and  FIG. 5 , the tire  38  according to the present exemplary embodiment is similar in structure to a conventional publicly known pneumatic tire apart from the bands  30 . Accordingly, structures other than the bands  30  are described briefly. The tire  38  is provided with: a pair of bead cores  42 ; a carcass  44 , which is an example of a tire carcass member, spanning between one of the bead cores  42  and the other of the bead cores  42 ; the spiral belt layer  28  disposed at the tire diameter direction outer side of the carcass  44 ; the tread  32  disposed at the tire diameter direction outer side of the spiral belt layer  28 ; the side rubber layer  40  disposed at the tire diameter direction outer side of the carcass  44 ; an inner liner  46  disposed at the tire inner face side of the carcass  44 ; and a bead filler  48  disposed between a main body portion and a folded back portion of the carcass  44 . 
     Similarly to the first exemplary embodiment, the bands  30  are provided at the tire diameter direction outer side of the spiral belt layer  28  so as to cover the two tire width direction end portions of the spiral belt layer  28 . 
     In the tire  38  according to the present exemplary embodiment, a reinforcement layer  50  is provided at a tire width direction central region of the spiral belt layer  28 . However, the reinforcement layer  50  need not be provided. 
     The tire  38  according to the present exemplary embodiment differs from the tire  10  in the basic structure of the carcass. However, an operational effect of improving the RFV is similar to the first exemplary embodiment. 
     Examples 
     To verify the effect of the present invention, a tire 1 and a tire 2 according to Examples were prepared. Tire 1 included the structures of the first exemplary embodiment described above. In tire 2, the bands were omitted from tire 1. The RFV of each tire was measured using an RFV tester. 
     Below, supplementary descriptions of structures of tires 1 and 2 are givent.
         Tire size: 225/40R18   Air pressure: 200 kPa       

     Spiral belt layer: Formed by winding a belt cord with width 5 mm and thickness 2.6 mm, in which two steel cords with thickness 1.33 mm (1+6×0.34) are coated with resin. 
     Band: Formed by winding a belt-shaped member provided with six nylon cords with thickness 0.54 mm. 
       FIG. 6  shows the RFV curve of tire 2 and  FIG. 7  shows the RFV curve of tire 1. From the RFV curve in  FIG. 6  and the RFV curve in  FIG. 7 , it can be seen that the RFV is improved in tire 1 that employs the present invention. Furthermore, the difference between a maximum value and minimum value of the RFV curve of tire 1 is 97 N, and the difference between a maximum value and minimum value of the RFV curve of tire 1 is 56 N. Thus, it can be seen that a large improvement effect is provided by application of the present invention. 
     Alternative Embodiments 
     Hereabove, exemplary embodiments of the present invention are described. The present invention is not limited by these descriptions and it will be clear that numerous modifications beyond these descriptions may be embodied within a technical scope not departing from the gist of the invention. 
     In the spiral belt layer  28  according to the first exemplary embodiment, the end portion  28 Ce 1  at the one side of the resin-coated cord  28 C and the end portion  28 Ce 2  at the other side are disposed to be offset by 22° in the tire circumference direction, but the present invention is not limited thus. For example, as illustrated in  FIG. 8A , the end portion  28 Ce 1  at the one side and the end portion  28 Ce 2  at the other side may be disposed to be offset by 180° in the circumference direction or, as illustrated in  FIG. 9A , the end portion  28 Ce 1  at the one side and the end portion  28 Ce 2  at the other side may be disposed to not be offset in the circumference direction. 
     An RFV curve of, for example, a configuration of the spiral belt layer  28  in which the end portion  28 Ce 1  at the one side of the resin-coated cord  28 C and the end portion  28 Ce 2  at the other side are disposed to be offset by 180° in the circumference direction as shown in  FIG. 8A  is schematically shown in  FIG. 8B  (the number of strands of the resin-coated cord  28 C in the region from 0° to 180° is greater than in the region from 180° to 360°). In this configuration, it is preferable if the overlap portion  30 B of each band  30  is disposed in the vicinity of 270° to raise the valley portion of the RFV curve. 
     Further, an RFV curve of a configuration of the spiral belt layer  28  in which the end portion  28 Ce 1  at the one side of the resin-coated cord  28 C and the end portion  28 Ce 2  at the other side are not offset by 180° in the circumference direction as shown in  FIG. 9A  is schematically shown in  FIG. 9B , in which the valley portion of the RFV curve is formed at a circumference direction position at the opposite side from the end portion  28 Ce 1  at the one side and the end portion  28 Ce 2  at the other side. Accordingly, in this configuration it is preferable if the overlap portion  30 B of the band  30  is disposed in the vicinity of 180° to raise the valley portion of the RFV curve. 
     In any case, an RFV curve may be improved by disposing the overlap portion  30 B of the band  30  at a position corresponding to a valley portion of the RFV curve (if the band  30  were absent) to raise the valley portion of the RFV curve. It is sufficient that a length in the circumference position and position in the circumference direction of the overlap portion  30 B are suitably altered in accordance with the length, position and the like of the overlap region  28 D of the spiral belt layer  28  and that the overlap portion  30 B is suitably disposed in accordance with the RFV curve of the tire if the band  30  were absent. 
     In the tire  30  according to the exemplary embodiments described above, the overlap portion  30 B is formed by a portion at one side in the length direction of the belt-shaped member  30 A and a portion at the other side in the length direction being superposed with one another in the diameter direction. However, for example, as illustrated in  FIG. 10 , the overlap portion  30 B may be formed by mating and joining circumferential direction end portions of a single circumference winding of the belt-shaped member  30 A with one another and then attaching a belt-shaped member  30 C, which has a short length in the circumference direction, to the diameter direction outer side of the joining region. 
     The present invention may be applied to a side-reinforcement-type run-flat tire in which a reinforcing layer formed of stiff rubber or the like is provided in a tire side portion. The present invention is not limited to tires for four-wheel vehicles and may be applied to tires for two-wheel vehicles. 
     The disclosures of Japanese Patent Application No. 2017-238599 filed Dec. 13, 2017 are incorporated into the present specification by reference in their entirety. 
     All references, patent applications and technical specifications cited in the present specification are incorporated by reference into the present specification to the same extent as if the individual references, patent applications and technical specifications were specifically and individually recited as being incorporated by reference.