Patent Publication Number: US-2021162812-A1

Title: Tire

Description:
TECHNICAL FIELD 
     The present disclosure relates to a tire. 
     BACKGROUND ART 
     Japanese Patent Application Laid-Open (JP-A) No. 2014-210487 discloses a tire with a configuration in which a reinforcing cord is covered in resin to form a reinforcing cord member, and the reinforcing cord member is wound in a spiral pattern onto an outer circumference of a tire frame member. This tire includes a belt configured by joining the reinforcing cord member that has been wound in a spiral pattern onto the outer circumference of the tire frame member to the outer circumference of the tire frame member, and joining together portions of the reinforcing cord member that are adjacent to each other in a tire axial direction. 
     SUMMARY OF INVENTION 
     Technical Problem 
     In JP-A No. 2014-210487, the reinforcing cord member configured by covering the reinforcing cord in resin has a rectangular shaped cross-section profile, and adjacent portions of this reinforcing cord member that have rectangular shaped cross-section profiles are joined together in the tire axial direction. Since join faces between the mutually adjacent portions of the reinforcing cord member in the tire axial direction run in the same direction with respect to the tire radial direction, there is room for improvement with respect to the level of join in the reinforcing cord member. 
     In consideration of the above circumstances, an object of the present disclosure is to improve the level of join of a resin-covered cord that forms a belt, and thus improve the durability of a tire. 
     Solution to Problem 
     A tire according to the present disclosure includes a circular tire frame member, a first resin-covered cord, a second resin-covered cord, and a belt. The first resin-covered cord is formed with a reinforcing cord that is covered in resin, the first resin-covered cord having a cross-section profile in a tire axial direction in which a pair of opposing edges are disposed so as to oppose each other in a tire radial direction and a protruding shape is formed protruding from one of the pair of opposing edges toward the other of the pair of opposing edges, in a case in which the first resin-covered cord has been wound in a spiral pattern onto an outer circumference of the tire frame member. The second resin-covered cord is formed with a reinforcing cord that is covered in resin, the second resin-covered cord together with the first resin-covered cord have a cross-section profile in which opposing edges at different sides from the pair of opposing edges of the first resin-covered cord are inclined in the same direction with respect to the tire radial direction, in a case in which the second resin-covered cord has been wound in a spiral pattern onto the outer circumference of the tire frame member so as to contact the first resin-covered cord in the tire axial direction. The belt is configured by the first resin-covered cord and the second resin-covered cord, the first resin-covered cord being wound so as to protrude toward one side in the tire radial direction, the second resin-covered cord being wound so as to be disposed between portions of the first resin-covered cord that are adjacent in the tire axial direction, the first resin-covered cord and the second resin-covered cord being joined together at a join face configured by entire faces that oppose each other in the tire axial direction of the first resin-covered cord and the second resin-covered cord, and the first resin-covered cord and the second resin-covered cord being joined to the tire frame member. 
     In the tire of the present disclosure, the first resin-covered cord and the second resin-covered cord are wound in spiral patterns onto the outer circumference of the circular tire frame member to form the belt. The first and second resin-covered cords are formed by covering the reinforcing cord in resin, and the reinforcing cord is wound in a spiral pattern onto the outer circumference of the tire frame member. 
     In the belt, the first resin-covered cord is wound so as to protrude toward the one side in the tire radial direction, and the second resin-covered cord is wound so as to be disposed between portions of the first resin-covered cord that are adjacent in the tire axial direction, such that the first and second resin-covered cords are alternately disposed along the tire axial direction. Moreover, the first resin-covered cord and the second resin-covered cord of the belt are joined to the outer circumference of the tire frame member, and the join face configured by the entire faces that oppose each other in the tire axial direction of the first resin-covered cord and the second resin-covered cord are joined together. 
     Note that in the cross-section profile in the tire axial direction of the first resin-covered cord, the pair of opposing edges are disposed so as to oppose each other in the tire radial direction, and a protruding shape is formed protruding from one of the pair of opposing edges toward the other of the pair of opposing edges. When the second resin-covered cord has been wound in a spiral pattern onto the outer circumference of the tire frame member so as to contact the first resin-covered cord in the tire axial direction, the second resin-covered cord together with the first resin-covered cord form a cross-section profile in which the opposing edges at different sides from the pair of opposing edges of the first resin-covered cord are inclined in the same direction with respect to the tire radial direction. 
     Thus, slopes of the join faces of the second resin-covered cord differ at the other side in the tire radial direction (acute angle side) with respect to the both sides in the tire axial direction of the first resin-covered cord, such that join faces with different slopes with respect to the tire radial direction are alternately formed along the tire axial direction in the belt. Since the join faces with different slopes (orientations) with respect to the tire radial direction can be alternately formed along the tire axial direction, there is no specific orientation in the belt and the durability of the belt can be improved in comparison to cases in which the join faces are oriented in the same direction. This enables the durability of the tire to be improved. 
     Advantageous Effects of Invention 
     The present disclosure has an advantageous effect of enabling the join faces with different orientations with respect to the tire radial direction to be alternately provided along the tire axial direction, thereby enabling the durability of the belt in which the first and second resin-covered cords are joined together to be improved, and enabling the durability of the tire to be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-section illustrating relevant portions of a tire according to an exemplary embodiment, on one side of a tire equatorial plane. 
         FIG. 2  is a cross-section illustrating relevant portions of a belt according to an exemplary embodiment. 
         FIG. 3  is a cross-section illustrating relevant portions of a belt provided to a tire, as sectioned along a tire axial direction. 
         FIG. 4  is a schematic diagram of relevant portions in a winding process of a resin-covered cord. 
         FIG. 5  is a schematic diagram illustrating winding of a resin-covered cord onto a core using a press roller. 
         FIG. 6A  is a cross-section illustrating relevant portions of a belt according to a modified example, as sectioned along the tire axial direction. 
         FIG. 6B  is a cross-section illustrating relevant portions of a belt according to another modified example, as sectioned along the tire axial direction. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Detailed explanation follows regarding exemplary embodiments of the present invention, with reference to the drawings. 
     A tire according to the present disclosure includes a circular tire frame member, a first resin-covered cord, a second resin-covered cord, and a belt. The first resin-covered cord is formed by covering a reinforcing cord in resin. When the first resin-covered cord has been wound in a spiral pattern onto an outer circumference of the tire frame member, a cross-section profile in a tire axial direction of the first resin-covered cord has a pair of opposing edges that are disposed opposing each other in a tire radial direction and a protruding shape that is formed protruding from one toward the other of the pair of opposing edges. The second resin-covered cord is formed by covering a reinforcing cord in resin. When the second resin-covered cord has been wound in a spiral pattern onto the outer circumference of the tire frame member so as to contact the first resin-covered cord in the tire axial direction, the second resin-covered cord forms a cross-section profile together with the first resin-covered cord in which opposing edges, which are located at different sides from the pair of opposing edges of the first resin-covered cord, are inclined in the same direction with respect to the tire radial direction. The belt is configured by winding the first resin-covered cord so as to protrude toward one side in the tire radial direction, winding the second resin-covered cord so as to be disposed between portions of the first resin-covered cord that are adjacent in the tire axial direction, joining the first resin-covered cord and the second resin-covered cord together at a join face configured by faces of the first resin-covered cord and the second resin-covered cord that oppose each other in the tire axial direction, and joining the first resin-covered cord and the second resin-covered cord to the tire frame member. 
     A tire of the present disclosure may be configured such that the second resin-covered cord is formed with a cross-section profile in the tire axial direction in which a pair of opposing edges are disposed so as to oppose each other in the tire radial direction and a protruding shape is formed protruding from one toward the other of the pair of opposing edges, and the belt is configured by winding the second resin-covered cord between the portions of the first resin-covered cord such that the second resin-covered cord protrudes toward an opposite side from the one side in the tire radial direction. 
     A tire of the present disclosure may be configured such that at least one of the first resin-covered cord or the second resin-covered cord includes plural reinforcing cords arrayed along the tire axial direction. 
     A tire of the present disclosure may be configured such that the cross-section profile in the tire axial direction of the second resin-covered cord is obtained by rotating the tire axial direction cross-section profile of the first resin-covered cord about a tire circumferential direction until the cross-section profile of the first resin-covered cord is inverted in the tire radial direction. 
     In the present exemplary embodiment, explanation follows regarding an example of a tire  10  serving as a pneumatic tire according to the present disclosure.  FIG. 1  is a schematic cross-section illustrating relevant portions of the tire  10  according to the present exemplary embodiment on one side of a tire equatorial plane CL. In the drawings, the arrow R indicates a tire radial direction, the arrow W indicates the tire axial direction (also referred to as a tire width direction), and the reference numeral CL indicates the tire equatorial plane. 
     In the present exemplary embodiment, the tire axial direction refers to a direction running parallel to a tire rotation axis, and corresponds to the tire width direction. In the present exemplary embodiment, a side further from the tire equatorial plane CL in the tire axial direction is referred to as the tire axial direction outer side, and a side closer to the tire equatorial plane CL in the tire axial direction is referred to as the tire axial direction inner side. In the present exemplary embodiment, the tire radial direction is a direction that intersects the tire axial direction. A side further away from the tire rotation axis in the tire radial direction is referred to as the tire radial direction outer side, and a side closer to the tire rotation axis in the tire radial direction is referred to as the tire radial direction inner side. In the present exemplary embodiment, the tire circumferential direction refers to a rotation direction centered on the tire rotation axis. 
     In the present exemplary embodiment, “parallel” refers to a state in which extension lines of two mutually opposing lines are considered as non-intersecting for practical purposes. Within the scope of the present exemplary embodiment, it is sufficient that no such intersection is envisaged, and does not indicate the absence of an intersection. 
     The dimension measurement methods for the various sections are the methods defined in the 2018 Year Book issued by the Japan Automobile Tyre Manufacturers Association (JATMA). In cases in which TRA standards or ETRTO standards apply in the location of use or manufacture, then the applicable standards are adhered to. 
     The tire  10  is what is referred to as a radial tire and is employed in a passenger car or the like. As illustrated in the example in  FIG. 1 , the tire  10  includes a pair of bead portions  14  each embedded with an annular bead core  12 , side portions  16  continuing toward the tire radial direction outer side from the respective bead portions  14 , and a crown portion  18  that couples together the side portions  16  on both sides in the tire width direction (tire axial direction). 
     Each of the bead cores  12  is configured by a bead cord (not illustrated in the drawings). The bead cord is configured of a metal cord such as a steel cord, an organic fiber cord, a resin-covered organic fiber cord, a hard resin, or the like. Note that the bead core  12  may be omitted from the bead portion  14  if the rigidity of the bead portion  14  can be sufficiently secured. 
     Each of the side portions  16  forms a portion at the side of the tire  10 , and is applied with a gentle convex curve toward an outer side in the tire axial direction from the bead portion  14  toward the crown portion  18 . A tread  20  is laid at an outer side in the tire radial direction of the tire  10 . The crown portion  18  configures a portion to support the tread  20 . 
     A carcass ply  22  that is wrapped around the respective bead cores  12  straddles between the pair of bead portions  14 . The carcass ply  22  is an example of a circular tire frame member, and is for example configured by cords (not illustrated in the drawings) arrayed in the tire circumferential direction and covered with rubber. Note that the tire frame member is not limited to the carcass ply  22 , and a member configured of a resin material may be employed. A reinforcing material (such as a polymer material, metal fibers, cord, non-woven fabric, or woven fabric) may be embedded in a resin tire frame member as appropriate. 
     The tire  10  includes an annular belt  30 , serving as a reinforcing member. The belt  30  employs a resin-covered cord  32  configuring both a first resin-covered cord and a second resin-covered cord.  FIG. 2  is a cross-section illustrating relevant portions of the belt  30 , as sectioned along the tire axial direction.  FIG. 3  is a cross-section illustrating relevant portions of the tire  10  as sectioned along the tire axial direction. 
     As illustrated in  FIG. 1  and  FIG. 3 , the belt  30  of the tire  10  is laid around an outer circumference of the carcass ply  22 . The belt  30  is joined to the outer circumference of the carcass ply  22  at the crown portion  18 . The tread  20  is joined to the tire radial direction outer side of the belt  30  through non-illustrated cushioning rubber 
     As illustrated in  FIG. 2  and  FIG. 3 , the resin-covered cord  32  is formed by covering one or plural reinforcing cords  36  with resin, namely with covering resin  34  such that the reinforcing cords  36  are fully enclosed within the covering resin  34 . A monofilament (single strand) of metal fiber, organic fiber, or the like, or a multifilament (twisted strands) configured by twisting fibers together is employed for each of the reinforcing cords  36 . In the present exemplary embodiment, steel cord is employed for the reinforcing cords  36 . For example, 1×5 steel cord with a diameter of 0.225 mm may be employed for the reinforcing cords  36 , or another known steel cord structure may be employed. 
     A resin material having a higher tensile elastic modulus than the rubber configuring the side portions  16  and the rubber configuring the tread  20  is employed for the covering resin  34  that covers the reinforcing cords  36  of the resin-covered cord  32 . For example, a thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like that has elastic properties may be employed as the covering resin  34  covering the reinforcing cords  36 . In consideration of elasticity during vehicle travel and molding properties during manufacture, a thermoplastic elastomer is preferably employed therefor. 
     Thermoplastic resins (including thermoplastic elastomers) are polymer compounds of materials that soften and flow with increased temperature, and that adopt a relatively hard and strong state when cooled. In the first exemplary embodiment, out of these, polymer compounds forming materials that soften and flow with increasing temperature, that adopt a relatively hard and strong state on cooling, and that have a rubber-like elasticity are considered to be thermoplastic elastomers. Polymer compounds forming materials that soften and flow with increasing temperature, that adopt a relatively hard and strong state on cooling, and do not have a rubber-like elasticity are considered to be non-elastomer thermoplastic resins, these being distinct from thermoplastic elastomers. 
     Examples of thermoplastic resins (including thermoplastic elastomers) include thermoplastic polyolefin-based elastomers (TPO), thermoplastic polystyrene-based elastomers (TPS), thermoplastic polyamide-based elastomers (TPA), thermoplastic polyurethane-based elastomers (TPU), thermoplastic polyester-based elastomers (TPC), and dynamically crosslinking-type thermoplastic elastomers (TPV), as well as thermoplastic polyolefin-based resins, thermoplastic polystyrene-based resins, thermoplastic polyamide-based resins, and thermoplastic polyester-based resins. 
     For example, a material with deflection temperature under load (namely under a load of 0.45 MPa) as defined in ISO 75-2 and ASTM D648 of 78° C. or above, a tensile yield strength as defined in JIS K7113 of 10 MPa or above, a tensile elongation at break as also defined in JIS K7113 of 50% or above, and a Vicat softening temperature as defined in JIS K7206 (method A) of 130° C. may be employed as the above thermoplastic material. 
     The tensile elastic modulus (as defined in JIS K7113: 1995) of the covering resin  34  that covers the reinforcing cords  36  is preferably no less than 100 MPa. An upper limit of the tensile elastic modulus of the covering resin  34  is preferably no greater than 1000 MPa. Note that the tensile elastic modulus of the covering resin  34  that covers the reinforcing cords  36  is preferably between 200 MPa and 700 MPa. 
     Thermosetting resins are curable polymer compounds that form a three-dimensional mesh structure with increasing temperature. Examples of thermosetting resins include phenolic resins, epoxy resins, melamine resins, and urea resins. Note that in addition to the thermoplastic resins (including thermoplastic elastomers) or thermosetting resins such as those described above, a general purpose resin such as a (meth)acrylic-based resin, an EVA resin, a vinyl chloride resin, a fluorine-based resin, or a silicone-based resin may be employed as the resin material. 
     In the present exemplary embodiment, two of the reinforcing cords  36  are employed in the resin-covered cord  32  as an example. In cross-section sectioned along the tire axial direction, the resin-covered cord  32  has a substantially rectangular profile with its length in an array direction of the reinforcing cords  36 . A thickness dimension of the resin-covered cord  32  configuring the belt  30  (a thickness dimension in a direction intersecting the array direction of the reinforcing cords  36 ) is preferably greater than a diameter dimension of the reinforcing cords  36 . In other words, the reinforcing cords  36  are preferably completely embedded in the covering resin  34 . Specifically, in cases in which the tire  10  is to be employed in a passenger car, the thickness dimension of the resin-covered cord  32  is preferably no less than 0.700 mm. 
     The resin-covered cord  32  applied in the present exemplary embodiment has a cross-section profile that is trapezoidal-shaped in the tire axial direction in which a pair of opposing edges of a substantial rectangle run parallel to each other, and a protruding shape is formed protruding from one toward the other of the pair of opposing edges. In the present exemplary embodiment, the trapezoidal shaped cross-section profile of the resin-covered cord  32  does not include rectangular or parallelogram shapes. In the present exemplary embodiment, as an example, the resin-covered cord  32  has a cross-section profile that is isosceles trapezoidal shaped in the tire axial direction. 
     As illustrated in  FIG. 3 , the resin-covered cord  32  of the belt  30  is laid such that the array direction of the reinforcing cords  36  runs along the tire axial direction. In cross-section of the resin-covered cord  32  along the tire axial direction, the array direction of the reinforcing cords  36  in the resin-covered cord  32  is a direction running parallel to a line linking the centers of the two reinforcing cords  36 . Note that in cases in which three or more of the reinforcing cords  36  are employed, the reinforcing cords  36  are arrayed such that the respective centers thereof are on the same straight line, and the array direction is a direction running substantially parallel to a line linking the centers of the respective reinforcing cords  36 . 
     As illustrated in  FIG. 2 , in a tire axial direction cross-section (cross-section along the tire axial direction), a lower base  38 A and an upper base  38 B of the resin-covered cord  32  run substantially parallel to each other, and a length a of the lower base  38 A is longer than a length b of the upper base  38 B (a&gt;b). A length c of a leg  38 C and a length d of a leg  38 D of the resin-covered cord  32  are substantially equal (c=d). Namely, the resin-covered cord  32  has the cross-section profile in the tire axial direction that protrudes from the lower base  38 A toward the upper base  38 B. 
     Thus, in the resin-covered cord  32 , an angle (acute angle-side angle) α 1  between the lower base  38 A and the leg  38 C, and an angle (acute angle-side angle) α 2  between the lower base  38 A and the leg  38 D are substantially equal (α 1 =α 2 , referred to as the angle α). Moreover, in the resin-covered cord  32 , an angle β 1  (an obtuse angle-side angle opposing the angle between the lower base  38 A and the leg  38 D) between the upper base  38 B and the leg  38 C, and an angle β 2  (an obtuse angle-side angle opposing the angle between the lower base  38 A and the leg  38 C) between the upper base  38 B and the leg  38 D are substantially equal (β 1 =β 2 , referred to as the angle (β). In the resin-covered cord  32 , the angle a and the angle β have a supplementary angle relationship (α+β=180°, α 1 +β 1 =180°, α 2 +β 2 =β180°). In other words, a cross-section profile of the resin-covered cord  32  along the tire axial direction has line symmetry about a line running along the tire radial direction at a tire axial direction intermediate position of the resin-covered cord  32 . 
     As illustrated in  FIG. 3 , a resin-covered cord  32  (hereafter referred to as the resin-covered cord  32 A when making a particular distinction) is wound in a spiral pattern with its lower base  38 A side at the tire radial direction inner side of the belt  30 . Moreover, a resin-covered cord  32  (hereafter referred to as the resin-covered cord  32 B when making a particular distinction) is wound with its upper base  38 B side at the tire radial direction inner side of the belt  30 , between the resin-covered cord  32  that has been wound with its lower base  38 A side at the tire radial direction inner side. Namely, the resin-covered cord  32 A serving as the first resin-covered cord and the resin-covered cord  32 B serving as the second resin-covered cord are employed as the resin-covered cord  32  of the belt  30 . 
     In the belt  30 , the resin-covered cord  32 A with its lower base  38 A side at the tire radial direction inner side and the resin-covered cord  32 B with its upper base  38 B side at the tire radial direction inner side are laid alternately along the tire axial direction. The resin-covered cord  32 A that protrudes toward the tire radial direction outer side and the resin-covered cord  32 B that protrudes toward the tire radial direction inner side are wound in a spiral pattern so as to appear alternately along the tire axial direction in the belt  30 . 
     In the belt  30 , the resin-covered cord  32 A and resin-covered cord  32 B that are adjacent in the tire axial direction are joined by being welded together. Note that this join of the resin-covered cord  32 A and the resin-covered cord  32 B is not limited to welding, and the resin-covered cord  32 A and the resin-covered cord  32 B may be joined together using an adhesive material. 
     Thus, in the belt  30 , a joined portion  40 A configuring a join face between respective leg  38 C-side faces of the resin-covered cords  32 A,  32 B, and a joined portion  40 B configuring a join face between respective leg  38 D-side faces of the resin-covered cords  32 A,  32 B are alternately formed along the tire axial direction. Weld interfaces are formed at the joined portions  40 A,  40 B of the belt  30 . The weld interfaces are formed running along the join faces of the joined portions  40 A,  40 B. 
     The joined portions  40 A,  40 B are sloped at the angle a with respect to the tire radial direction inner side of the resin-covered cords  32 A,  32 B. The joined portions  40 A,  40 B are sloped in different directions such that the joined portions  40 A,  40 B face away from each other (toward the tire radial direction outer side) from the tire radial direction inner side. Thus, the orientations of the weld interfaces formed at the joined portions  40 A,  40 B differ between the joined portion  40 A and the joined portion  40 B. 
     The belt  30  is formed in an annular shape by winding the elongated resin-covered cords  32 A,  32 B in a spiral pattern. In the belt  30 , the resin-covered cords  32 A,  33 B that are adjacent in the tire axial direction are welded together at the joined portions  40 A,  40 B. In a state in which the resin-covered cords  32 A,  32 B of the belt  30  have been wound in a spiral pattern onto the outer circumference of the carcass ply  22  of the crown portion  18 , the lower base  38 A of the resin-covered cord  32 A and the upper base  38 B of the resin-covered cord  32 B are joined to the outer circumference of the carcass ply  22 . 
     During this joining of the belt  30  to the carcass ply  22 , the covering resin  34  at the lower base  38 A of the resin-covered cord  32 A and the upper base  38 B of the resin-covered cord  32 B of the belt  30  is melted, and the belt  30  is pressed against the carcass ply  22 . Thus, in the belt  30 , the joined portions  40 A,  40 B are alternately formed along the tire axial direction, and the joined portions  40 A,  40 B are oriented in different directions from each other at the angle a with respect to the tire radial direction. The joined portions  40 A,  40 B have weld interface that are oriented in different directions are thereby alternately formed along the tire axial direction in the belt  30 . 
     Operation 
     In the tire  10  of the present exemplary embodiment, the belt  30  is joined to the outer circumference of the carcass ply  22  of the crown portion  18 . The resin-covered cord  32  ( 32 A,  32 B) of the belt  30  is wound in a spiral pattern onto the outer circumference of the carcass ply  22 . The reinforcing cords  36  in the resin-covered cords  32 A,  32 B of the belt  30  are covered by the covering resin  34 , and the resin-covered cords  32 A,  32 B are welded to the outer circumference of the carcass ply  22 . 
     In the belt  30 , the resin-covered cords  32 A,  32 B that are adjacent in the tire axial direction are melted and welded (joined) together at the respective joined portions  40 A,  40 B, thereby forming the weld interfaces where the covering resin  34  is welded together at the joined portions  40 A,  40 B. 
     In the belt  30  of the tire  10 , there is a tendency for stress to concentrate at locations where rigidity changes, and bending moment arises around the tire circumferential direction in the belt  30  during vehicle travel and the like. Accordingly, there is a tendency for stress to concentrate at the joined portions  40 A,  40 B of the belt  30  where the weld interfaces are formed between the resin-covered cords  32 A,  32 B configured by covering the reinforcing cords  36  with the covering resin  34 . 
     The resin-covered cords  32 A,  32 B having the cross-section profiles that are trapezoidal shaped in the tire axial direction are employed in the belt  30 . The weld interfaces at the joined portions  40 A,  40 B between the resin-covered cords  32 A,  32 B that are adjacent in the tire axial direction have different orientations to each other. 
     Accordingly, in the belt  30 , a reduction in weld pressure due to a concentration of stress at the joined portions  40 A,  40 B is suppressed in comparison to cases in which the orientations of the weld interfaces are aligned in a uniform direction. A reduction (reduction over time) in the join properties at the joined portions  40 A,  40 B is thus suppressed, even if stress concentrates at the joined portions  40 A,  40 B of the belt  30  employing the resin-covered cords  32 A,  32 B configured by covering the reinforcing cords  36  with the covering resin  34 . This thereby improves the durability of the belt  30  joined to the outer circumference of the carcass ply  22  in the tire  10 , and thus improves the durability of the tire  10 . 
     A single type of the resin-covered cord  32  is applied in the belt  30 , and the resin-covered cord  32  is disposed with its upper base  38 B side facing the tire radial direction outer side when employed as the resin-covered cord  32 A, and is disposed with its upper base  38 B side facing the tire radial direction inner side when employed as the resin-covered cord  32 B. This enables manufacturing efficiency of the belt  30  of the tire  10  to be improved in comparison to cases in which two types of resin-covered cord having different profiles to each other are employed, and the manufacturing cycle of the belt  30  is made shorter. This enables an increase in the manufacturing cycle of the tire  10 , which employs the belt  30  formed using the two resin-covered cords  32 A,  32 B, to be suppressed. 
     Moreover, the resin-covered cord  32  ( 32 A,  32 B) is configured with the cross-section profile that is an isosceles trapezoidal shape in the tire axial direction. This enables the slope angles of the joined portions  40 A,  40 B between the resin-covered cords  32 A,  32 B of the belt  30  with respect to the tire radial direction inner side to be made similar to each other, and also facilitates sloping of the joined portions  40 A,  40 B toward opposite sides in the tire axial direction. This facilitates manufacture of the belt  30  with improved durability, and thus enables the durability of the tire  10  to be effectively improved. Moreover, when forming the resin-covered cord  32  ( 32 A,  32 B) by resin extrusion molding or the like, since the cross-section profile in the tire axial direction of the resin-covered cord  32  ( 32 A,  32 B) is defined as a substantially isosceles trapezoidal shape, easier molding is enabled, thus production efficiency of the resin-covered cord  32  ( 32 A,  32 B) is improved. 
     Belt Manufacture 
     Next, explanation follows regarding manufacture of the annular belt  30 . As an example, an annular (drum shaped) core  46  is employed in the manufacture of the belt  30  in the present exemplary embodiment.  FIG. 4  is a schematic configuration diagram illustrating relevant portions in a manufacturing process of the belt  30 .  FIG. 5  is a schematic diagram illustrating relevant portions of the core  46  as viewed along an axial direction. 
     As illustrated in  FIG. 4 , an outer circumference of the core  46  configures a winding surface  46 A for the resin-covered cord  32 . The outer circumference (winding surface  46 A) of the core  46  is for example configured from metal. The outer circumference of the core  46  may have a linear cross-section profile along the axial direction or a curved cross-section profile along the axial direction, or may have a combination of a linear cross-section profile part and a curved cross-section profile part. The outer circumference of the core  46  is divisible at plural locations in a circumferential direction, and each of the divided outer circumferential portions is capable of moving so as to retreat toward an inner side in a radial direction (not illustrated in the drawings). This facilitates removal of the annular belt  30  formed on the outer circumference of the core  46 . 
     A support device (not illustrated in the drawings) that rotatably supports the core  46  is employed when winding the resin-covered cords  32 A,  32 B onto the outer circumference of the core  46 . The resin-covered cords  32 A,  32 B are wound using a cord supply device  50  that supplies the resin-covered cords  32 A,  32 B, a heating device  60  that heats the resin-covered cord  32 , a press roller  70  serving as a pressing implement, a cooling roller  72  serving as a cooling implement, and the like in the vicinity of the outer circumference of the core  46 . 
     The cord supply device  50  is configured including a reel  52  on which the resin-covered cord  32  is taken up, and a guide member  54  with a tubular internal portion through which the resin-covered cord  32  is able to pass. An opening  56  facing toward the outer circumference of the core  46  is formed in the guide member  54 . The resin-covered cord  32  that has taken up onto the reel  52  of the cord supply device  50  is used as the resin-covered cords  32 A,  32 B. 
     In the cord supply device  50 , the resin-covered cord  32  is pulled out from the reel  52  and guided by passing through the tubular internal portion of the guide member  54 . The resin-covered cord  32  is then fed out through the opening  56  toward the outer circumference of the core  46 . The reel  52  and the guide member  54  of the cord supply device  50  are inverted such that the resin-covered cord  32  is supplied onto the core  46  with positions of the lower base  38 A side and the upper base  38 B side of the resin-covered cord  32  being invert. The cord supply device  50  is thus capable of supplying the resin-covered cord  32  on the reel  52  as both the resin-covered cords  32 A and  32 B. 
     During manufacture of the belt  30 , the resin-covered cords  32 A,  32 B are fed onto the outer circumference of the core  46  by the cord supply device  50  while the core  46  is being rotated by the support device, such that the resin-covered cords  32 A,  32 B are wound onto the outer circumference of the core. When this is performed, the core  46  and the opening  56  in the cord supply device  50  (guide member  54 ) are moved relative to one another in the tire axial direction, causing the resin-covered cords  32 A,  32 B to be wound onto the outer circumference of the core  46  in a spiral pattern. Note that this relative movement between the core  46  and the opening  56  in the guide member  54  is for example performed by moving the core  46  along the tire axial direction. 
     Moreover, during manufacture of the belt  30 , after winding one of the resin-covered cords  32 A,  32 B onto the core  46  in a spiral pattern, the other of the resin-covered cords  32 A,  32 B is wound on in a spiral pattern. In the present exemplary embodiment, as an example, the resin-covered cord  32 A is wound onto the core  46  first, and then the resin-covered cord  32 B is wound onto the core  46 . 
     As illustrated in  FIG. 4  and  FIG. 5 , the heating device  60  is provided with a blower outlet  62 . The heating device  60  for example heats air using a heating element (not illustrated in the drawings) while using a fan (not illustrated in the drawings) to cause the heated air to flow to generated a heated airflow, and the heated airflow thus generated is blown out through a blower outlet  62   
     The blower outlet  62  of the heating device  60  opposes faces of the respective legs  38 C,  38 D of the resin-covered cord  32 A that has been wound onto the core  46  and the resin-covered cord  32 B that is being supplied to the core  46 . The heating device  60  blows the heated airflow against the faces of the respective legs  38 C,  38 D of the resin-covered cords  32 A,  32 B through the blower outlet  62  so as to melt the covering resin  34 . 
     Note that the heating device  60  may also blow the heated airflow through the blower outlet  62  when initially winding the resin-covered cord  32 A onto the core  46 . Moreover, the heating device  60  is not limited to a configuration employing a heating element and a fan. Any configuration capable of heating and melting the thermoplastic resin may be applied, for example a configuration in which a heating iron contacts the location to be melted (covering resin  34 ) such that the contact portion is heated and melted in this manner. Alternatively, the heating device  60  may employ radiant heat to heat and melt the location to be melted, or infrared light may be shone onto the location to be melted so as to heat and melt this location. 
     The press roller  70  presses the resin-covered cords  32 A,  32 B to be wound onto the core  46  against the outer circumference of the core  46 . The cooling roller  72  is disposed further toward a rotation direction downstream side of the core  46  than the press roller  70 . The cooling roller  72  presses the resin-covered cord  32 B that has been wound onto the outer circumference of the core  46 . A liquid cooling source (for example a coolant such as water) flows through the inside of the cooling roller  72 , such that heat exchange takes place between the liquid cooling source and the resin-covered cord  32 B when the roller surface of the cooling roller  72  contacts the resin-covered cord  32 B. 
     Note that the press roller  70  and the cooling roller  72  are capable of rotating freely, and undergo following rotation (rotation in the arrow B direction) with respect to the rotation direction of the core  46  (the arrow A direction) when pressed against the resin-covered cords  32 A,  32 B. The roller surfaces of the press roller  70  and the cooling roller  72  are treated so as to prevent molten resin material (covering resin  34 ) from adhering thereto. The press roller  70  and the cooling roller  72  are preferably capable of adjusting the pressing force (pressure) F applied to the resin-covered cords  32 A,  32 B. 
     The resin-covered cord  32 B that has been wound onto the core  46  and pressed by the press roller  70  is thus cooled by the cooling roller  72 , and the resin-covered cord  32 A that has been wound onto the core  46  and the core  46  itself are cooled through the resin-covered cord  32 B. Note that the cooling roller  72  may be omitted in cases in which the molten resin material (the covering resin  34  of the resin-covered cords  32 A,  32 B) is allowed to cool naturally. 
     During manufacture of the belt  30 , first the resin-covered cord  32 A is provisionally wound onto the outer circumference of the core  46 . During provisional winding of the resin-covered cord  32 A, the core  46  attached to the support device is rotated in the arrow A direction, and the resin-covered cord  32 A is pulled out from the reel  52  of the cord supply device  50  and fed toward the outer circumference of the core  46  through the opening  56 . During this provisional winding of the resin-covered cord  32 A, the resin-covered cord  32 A wound onto the core  46  is loosely wound in a spiral pattern around the outer circumference of the core  46 , such that a spacing between adjacent portions of the lower base  38 A of the resin-covered cord  32 A in a core axial direction is matched to the length b of the upper base  38 B of the resin-covered cord  32 B. When this is performed, tension is imparted to the resin-covered cords  32 A so as to suppress slippage of the resin-covered cords  32 A (slippage in the axial direction of the core  46 ). 
     During the provisional winding of the resin-covered cord  32 A, the spacing between portions of the lower base  38 A of the resin-covered cord  32 A that has been wound onto the core  46  is not allowed to become wider than the length b of the upper base  38 B of the resin-covered cord  32 B. Moreover, during the provisional winding of the resin-covered cord  32 A, the resin-covered cord  32 A is preferably provisionally fixed to the outer circumference of the core  46 , for example by blowing the heated airflow through the blower outlet  62  of the heating device  60 . 
     After this has been performed, the resin-covered cord  32 B is wound onto the core  46 . During winding of the resin-covered cord  32 B, the resin-covered cord  32 B is pulled out from the reel  52  of the cord supply device  50  and the resin-covered cord  32 B thus pulled out is supplied onto the outer circumference of the core  46  through the opening  56 . 
     During the winding of the resin-covered cord  32 B, the resin-covered cord  32 B is supplied between the provisionally wound and lined up resin-covered cord  32 A while blowing the heated airflow through the blower outlet  62  of the heating device  60  so as to heat the respective leg  38 C,  38 D-side faces of the resin-covered cords  32 A,  32 B. In addition thereto, the supplied resin-covered cord  32 B is pushed between the resin-covered cord  32 A by the press roller  70 . 
     The resin-covered cord  32 B is thus slotted between portions of the resin-covered cord  32 A and wound in a spiral pattern onto the outer circumference of the core  46 . The covering resin  34  of the resin-covered cords  32 A,  32 B wound onto the core  46  is melted by the heated airflow from the blower outlet  62  of the heating device  60  so as to weld the resin-covered cords  32 A,  32 B together at the joined portions  40 A,  40 B (the respective leg  38 C-side faces and leg  38 D-side faces) (thereby forming the weld interfaces). 
     Note that as illustrated in  FIG. 2 , in the resin-covered cord  32 A, the legs  38 C,  38 D are inclined toward the tire axial direction outer sides on progression from the tire radial direction outer side toward the tire radial direction inner side. In the resin-covered cord  32 B that is slotted between the portions of the resin-covered cord  32 A, the legs  38 C,  38 D are inclined toward the tire axial direction inner side on progression from the tire radial direction outer side toward the tire radial direction inner side. Accordingly, the resin-covered cord  32 B can easily be slotted between the portions of the resin-covered cord  32 A by being pushed toward the tire radial direction inner side by the press roller  70 . 
     Moreover, the leg  38 C-side face of the resin-covered cord  32 B contacts the leg  38 C-side face of the resin-covered cord  32 A at the joined portion  40 A, and the leg  38 D-side face of the resin-covered cord  32 B contacts the leg  38 D-side face of the resin-covered cord  32 A at the joined portion  40 B. The joined portions  40 A,  40 B are inclined by an acute angle (angle a) with respect to the tire radial direction, and the joined portions  40 A,  40 B are inclined in directions approaching each other at the tire radial direction inner side. Accordingly, the resin-covered cord  32 B presses the resin-covered cord  32 A toward the tire radial direction inner side and the tire axial direction outer sides when applied with the pressing force of the press roller  70 . This improves the tightness of contact between the resin-covered cords  32 A,  32 B at the joined portions  40 A,  40 B, such that the resin-covered cords  32 A,  32 B are welded together with a high weld strength pressure at the joined portions  40 A,  40 B, thus improving the join properties between resin-covered cords  32 A,  32 B at the joined portions  40 A,  40 B. 
     The resin-covered cords  32 A,  32 B have been welded together in this manner are then cooled and set by pressing the resin-covered cord  32 B with the cooling roller  72 . The belt  30  is accordingly manufactured by winding the resin-covered cords  32 A,  32 B in a spiral pattern onto the outer circumference of the core  46  in this manner. In the manufactured belt  30 , the weld interfaces oriented in different directions to each other are alternately formed along the tire axial direction. 
     Note that during manufacture of the belt  30 , the tension of the resin-covered cords  32 A,  32 B supplied to the core  46  may be adjusted by applying a brake to the reel  52  of the cord supply device  50 , by providing a tension adjustment roller (not illustrated in the drawings) on a guidance path of the resin-covered cords  32 A,  32 B, or the like. This enables snaking or the like of the resin-covered cords  32 A,  32 B as they are being wound onto the core  46  to be suppressed, enabling a high quality belt  30  to be manufactured in which the resin-covered cords  32 A,  32 B are wound on in a spiral pattern at a uniform pitch. 
     The manufactured belt  30  is then removed from the core  46 , and is pressure-welded to the outer circumference of the carcass ply  22  in a vulcanization process or the like to manufacture the tire  10 . Although the core  46  is employed during manufacture of the belt  30 , the carcass ply  22  may be employed instead of the core  46 , such that the belt  30  is manufactured by winding the resin-covered cords  32 A,  32 B in a spiral pattern onto the outer circumference of the carcass ply  22 . In such cases, the carcass ply  22  is attached to a support device, and the resin-covered cord  32 A and the resin-covered cord  32 B are then wound in spiral patterns onto the outer circumference of the carcass ply  22  in this sequence while rotating the carcass ply  22 . This enables the belt  30  to be manufactured by the resin-covered cords  32 A,  32 B being wound in spiral patterns onto the outer circumference of the carcass ply  22  and joined together. 
     Modified Examples of Belt 
     In the present exemplary embodiment, the belt  30  is formed employing the resin-covered cord  32  having the cross-section profile that is the isosceles trapezoidal shape in the tire axial direction and inverting the resin-covered cord  32  in the tire radial direction so as to use as the resin-covered cords  32 A,  32 B. 
     Note that it is sufficient that the second resin-covered cord, when joined to the first resin-covered cord, form a cross-section profile that is a parallelogram shape in the tire axial direction. Thus, the second resin-covered cord is not limited to having the cross-section profile that is a trapezoidal shape in the tire axial direction, and may have a triangular profile. Moreover, the first and second resin-covered cords are not limited to isosceles trapezoidal shaped profiles, and may be configured with trapezoidal shaped profiles other than isosceles trapezoidal shaped profiles that protrude from a lower base side toward an upper base side. 
       FIG. 6A  and  FIG. 6B  are schematic cross-sections taken along the tire axial direction illustrating relevant portions of belts according to modified examples of the present exemplary embodiment. 
     As illustrated in  FIG. 6A , a belt  76  employs the resin-covered cord  32  as a first resin-covered cord and employs a resin-covered cord  78  as a second resin-covered cord. As an example, the resin-covered cord  78  employs a single reinforcing cord  36 , this reinforcing cord  36  being covered with the covering resin  34 . As an example, the resin-covered cord  78  has a cross-section profile that is a isosceles triangle shape along the tire axial direction, the length of two edges  80 B,  80 C being similar to the length of the legs  38 C,  38 D of the resin-covered cord  32 . The cross-section profile in the tire axial direction of the resin-covered cord  78  has line symmetry about a line running along the tire radial direction through a tire axial direction intermediate position of the resin-covered cord  78 . 
     In the belt  76 , the resin-covered cord  78  is wound in a spiral pattern at a predetermined spacing in the tire axial direction, such that a base edge  80 A of the resin-covered cord  78  is on the tire radial direction inner side. The resin-covered cord  32  of the belt  76  is wound on in a spiral pattern so as to be slotted between portions of the resin-covered cord  78 , such that an upper base  38 B side of the resin-covered cord  32  is on the tire radial direction inner side (corresponding to the resin-covered cord  32 B side of the belt  30 ). In the belt  76 , a leg  38 C-side face of the resin-covered cord  32  and an edge  80 B-side face of the resin-covered cord  78  are joined together by welding at a join face (joined portion  82 B), and a leg  38 D-side face of the resin-covered cord  32  and an edge  80 C-side face of the resin-covered cord  78  are joined together by welding at a join face (joined portion  82 A). 
     Accordingly, in the belt  76 , the combined cross-section profiles in the tire axial direction of the resin-covered cord  32  and the resin-covered cord  78  configure a parallelogram shape. In the belt  76 , the joined portions  82 A,  82 B are alternately formed along the tire axial direction, and the joined portions  82 A,  82 B have similar incline angles to each other with respect to the tire radial direction inner side. However, the joined portions  82 A,  82 B are sloped in directions away from each other at the tire radial direction inner side (in directions approaching each other at the tire radial direction outer side if considered in the sequence joined portions  82 B,  82 A), such that the orientations of the weld interfaces between the joined portions  82 A,  82 B are different from each other. 
     Accordingly, weld interfaces with differing orientations are alternately formed along the tire axial direction, thus improving the durability of the belt  76  (in particular the durability with respect to bending moment on both sides of the belt  76  in the tire axial direction that are bent toward the tire radial direction outer side). The belt  76  is thus capable of improving the durability of the tire  10 . 
     As illustrated in  FIG. 6B , a belt  84  employs resin-covered cords  86 ,  88  as a first resin-covered cord and a second resin-covered cord. As an example, the resin-covered cord  86  is configured by two of the reinforcing cords  36  covered with the covering resin  34 , and as an example, the resin-covered cord  88  is configured by three of the reinforcing cords  36  covered with the covering resin  34 . 
     The resin-covered cord  86  has a cross-section profile in the tire axial direction in which a lower base  90 A and an upper base  90 B are parallel to each other, with a length of the lower base  90 A being longer than a length of the upper base  90 B, such that the resin-covered cord  86  protrudes toward an upper base  90 B side. Moreover, in the resin-covered cord  86 , a length of one leg  90 C is different from a length of the other leg  90 D. In this modified example, the length of the leg  90 C is longer than the length of the leg  90 D. 
     The resin-covered cord  88  has a cross-section profile in the tire axial direction in which a lower base  92 A and an upper base  92 B are parallel to each other, with a length of the lower base  92 A being longer than a length of the upper base  92 B, such that the resin-covered cord  88  protrudes toward an upper base  92 B side. Moreover, in the resin-covered cord  88 , a length of one leg  92 C is different from a length of the other leg  92 D. In this modified example, the length of the leg  92 C is longer than the length of the leg  92 D. 
     In the resin-covered cord  86 , an angle α 1  that is an acute angle between the lower base  90 A and the leg  90 C, and an angle α 2  that is an acute angle between the lower base  90 A and the leg  90 D are different from each other, and an angle β 1  that is an obtuse angle between the upper base  90 B and the leg  90 C and an angle β 2  that is an obtuse angle between the upper base  90 B and the leg  90 D are different from each other. Note that as an example, the angle α 2  is larger than the angle α 1  (0°&lt;α 1 &lt;α 2 ≤90°), and the angle β 2  is smaller than the angle β 1  (90°≤β 2 &lt;β 1 &lt;180°). Note that one of the angles α 1 , α 2  may be substantially a right angle. 
     In the resin-covered cord  88 , the acute angle between the lower base  92 A and the leg  92 C is set to the angle al, and the acute angle between the lower base  92 A and the leg  92 D is set to the angle α 2 . The obtuse angle between the upper base  92 B and the leg  92 C is set to the angle β 1 , and the obtuse angle between the upper base  92 B and the leg  92 D is set to the angle β 2 . 
     In the belt  84 , the resin-covered cord  86  is wound on in a spiral pattern at a predetermined spacing in the tire axial direction with the lower base  90 A of the resin-covered cord  86  on the tire radial direction inner side, and the resin-covered cord  88  is disposed between the resin-covered cord  86 . The resin-covered cord  88  is wound on in a spiral pattern with its upper base  92 B side at the tire radial direction inner side such that the resin-covered cord  88  is slotted between portions of the resin-covered cord  86  that are adjacent in the tire axial direction. 
     In the belt  84 , a leg  90 C-side face of the resin-covered cord  86  and a leg  92 C-side face of the resin-covered cord  88  are joined by being welded together at a join face (joined portion). A leg  90 D-side face of the resin-covered cord  86  and a leg  92 D-side face of the resin-covered cord  88  are joined by being welded together at a join face (joined portion). 
     Accordingly, in the belt  84 , the joined portions are alternately formed along the tire axial direction, the joined portions have different incline angles to each other with respect to the tire radial direction inner side, and are sloped in opposite directions at the tire radial direction inner side. 
     Accordingly, weld interfaces with differing orientations are alternately formed along the tire axial direction by the resin-covered cords  86 ,  88 , thus improving the durability of the belt  84  (in particular durability with respect to bending moment about the tire circumferential direction). The belt  84  is thus capable of improving the durability of the tire  10 . 
     The disclosure of Japanese Patent Application No. 2018-117343, filed on Jun. 20, 2018, is incorporated in its entirety by reference herein. 
     All cited documents, patent applications, and technical standards mentioned in the present specification are incorporated by reference in the present specification to the same extent as if each individual cited document, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.