Patent Publication Number: US-2021162814-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 onto an outer circumference of a tire frame member in a spiral pattern. This tire includes a belt configured by joining the reinforcing cord member that has been wound onto the outer circumference of the tire frame member in a spiral pattern 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 
     However, the reinforcing cord member in this related art has a rectangular cross-section profile, leaving room for further improvement with respect to the level of joining between mutually adjacent portions of the reinforcing cord member in the tire axial direction. 
     An object of the present disclosure is to improve the durability of a tire including a belt configured by winding a resin-covered cord in a spiral pattern. 
     Solution to Problem 
     A tire according to the present disclosure includes a belt joined to an outer circumference of a circular tire frame member, the belt being formed with a resin-covered cord that is wound in a spiral pattern, in a tire circumferential direction, onto the outer circumference of the tire frame member, and the resin-covered cord being configured by an arrangement of plural reinforcing cords that are covered with a thermoplastic resin. In a cross-section of the belt sectioned along a tire axial direction, the resin-covered cord is wound in the spiral pattern with an array direction of the reinforcing cords being inclined with respect to the tire axial direction, and portions of the inclined resin-covered cord that are adjacent to each other in the tire axial direction are welded together at mutual contact portions. 
     In the tire of the present disclosure, the belt is joined to the outer circumference of the circular tire frame member. The belt is formed by winding the resin-covered cord in a spiral pattern in the tire circumferential direction. The resin-covered cord is configured by the arrangement of the plural reinforcing cords that are covered with resin. In cross-section sectioned along the tire axial direction, the array direction of the reinforcing cords of resin-covered cord is inclined with respect to the tire axial direction. 
     Note that when due to arraying the plural reinforcing cords in the resin-covered cord, the tire axial direction cross-section profile of the resin-covered cord becomes longer in the array direction of the reinforcing cords. Inclining the array direction of the reinforcing cord of the resin-covered cord with respect to the tire axial direction enables the contact surface area between portions of the resin-covered cord adjacent to each other in the tire axial direction to be increased. This enables the level of joining between adjacent portions in the tire axial direction of the resin-covered cord of the belt to be improved, thus enabling the durability of the tire to be improved. 
     Advantageous Effects of Invention 
     The belt of the present disclosure, configured by winding the resin-covered cord in a spiral pattern, exhibits the advantageous effect of enabling the joining properties and thus the level of joining between the mutually adjacent portions in the tire axial direction of the resin-covered cord to be improved, thus 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 a first exemplary embodiment, on one side of a tire equatorial plane. 
         FIG. 2  is a schematic diagram of relevant portions of a belt according to the first exemplary embodiment, as viewed along a length direction. 
         FIG. 3  is a cross-section of relevant portions of a belt provided to a tire, as sectioned along a tire axial direction. 
         FIG. 4  is a schematic diagram illustrating relevant portions in a winding process of a resin-covered cord. 
         FIG. 5  is a line graph illustrating changes in a weld ratio with respect to an angle of inclination of a belt. 
         FIG. 6  is a cross-section illustrating relevant portions of a belt according to a second exemplary embodiment. 
     
    
    
     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 belt joined to an outer circumference of a circular tire frame member, the belt being formed by winding a resin-covered cord onto the outer circumference of the tire frame member in a tire circumferential direction so as to form a spiral pattern, and the resin-covered cord being configured by an arrangement of plural reinforcing cords that are covered with a resin. In a cross-section of the belt as sectioned along a tire axial direction, the resin-covered cord is wound in a spiral pattern such that an array direction of the reinforcing cords is inclined with respect to the tire axial direction, and portions of the inclined resin-covered cord that are adjacent to each other in the tire axial direction are joined together at a mutual contact portion. 
     In the tire according to the present disclosure, in a cross-section of the resin-covered cord sectioned along the tire axial direction, an obtuse angle-side angle of the incline of a face on the tire frame member side of the resin-covered cord with respect to the array direction of the reinforcing cords is an angle configuring a supplementary angle to an acute angle-side angle of the array direction of the reinforcing cords with respect to the tire axial 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 the 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 exemplary embodiments, the tire circumferential direction refers to a rotation direction centered on the tire rotation axis. 
     The dimension measurement methods for the various sections are the methods defined in the 2018 Year Book issued by the Japan Automobile Tire 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. 
     First Exemplary Embodiment 
     The tire  10  according to a first exemplary embodiment 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 the tire axial direction outer side from the bead portion  14  toward the crown portion  18 . A tread  20  is laid at the tire radial direction outer side 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 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.  FIG. 2  is a schematic configuration diagram of relevant portions of the belt  30  according to the first exemplary embodiment, as viewed along a length direction thereof.  FIG. 3  is an enlarged cross-section of relevant portions of the tire  10  in  FIG. 1  as sectioned along the tire axial direction. 
     As illustrated in  FIG. 1  and  FIG. 3 , the belt  30  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 , resin-covered cord  32  is employed in the belt  30 . The resin-covered cord  32  is formed by covering reinforcing cords  36  with covering resin  34  such that the reinforcing cords  36  are fully enclosed within the covering resin  34 . A monofilament (single strand) 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 . Plural of the reinforcing cords  36  are arrayed within the resin-covered cord  32 . An adhesive resin layer  36 A is provided at an outer periphery of each of the reinforcing cords  36 . The reinforcing cord  36  is joined to the covering resin  34  through the adhesive resin layer  36 A, thereby suppressing slippage of the reinforcing cords  36  with respect to the covering resin  34 . 
     As an example, a thermoplastic resin (including thermoplastic elastomers), serving as a resin material, is employed as the covering resin  34  of the resin-covered cord  32 . The resin material employed for the covering resin  34  is not limited to a thermoplastic elastomer, and in addition to thermoplastic resins, thermosetting resins, and other general-purpose resins, engineering plastics (including super engineering plastics) or the like may be employed as the resin material. 
     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 (see JIS K7113), 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 first 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 radial direction, the resin-covered cord  32  has a substantially rectangular (substantially elongated) profile with its length in an array direction of the reinforcing cords  36  (illustrated by a single-dotted dashed line in  FIG. 2 ). 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. 
     In the resin-covered cord  32  of the first exemplary embodiment, a width a, this being the length of side faces  32 A,  32 B along the array direction is longer (greater) than a thickness b configuring the lengths of side faces  32 C,  32 D on both sides in the array direction of the resin-covered cord  32  (a&gt;b). The resin-covered cord  32  is for example configured such that the width a is 5.0 mm and the thickness b is 2.0 mm. 
     Note that the spacing between the reinforcing cords  36  in the resin-covered cord  32  is set to a spacing that obtains a desired strength. The reinforcing cords  36  in the resin-covered cord  32  are covered by the covering resin  34  at a covering thickness that obtains a desired strength, and the width a and the length b of the resin-covered cord  32  are set such that the desired strength of the resin-covered cord  32  is obtained. 
     In cross-section of the resin-covered cord  32  as sectioned along the tire axial direction, the array direction of the reinforcing cords  36  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 substantially 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 . 
     The belt  30  is formed in an annular shape by winding the elongated resin-covered cord  32  in a spiral pattern. The belt  30  is welded together at a joined portions  38 , this being a portion where mutually adjacent portions of the resin-covered cord  32  in the tire axial direction contact each other (a contact portion). 
     Note that in the resin-covered cord  32 , the array direction of the reinforcing cords  36  is inclined by an acute angle α with respect to one side in the tire axial direction, such that the array direction of the reinforcing cords in the resin-covered cord  32  is inclined with respect to the tire radial direction by the angle of inclination (angle) α on the one side in the tire axial direction. The resin-covered cord  32  is wound around the outer circumference of the carcass ply  22  in a state in which the array direction of the reinforcing cords  36  is tilted by the angle of inclination α with respect to the one side in the tire axial direction (0°&lt;α&lt;90°). In other words, in the resin-covered cord  32 , one out of the side faces  32 A,  32 B running along the array direction of the reinforcing cords  36  (for example the side face  32 A) faces toward the tire radial direction inner side, and this side face  32 A is inclined by the angle of inclination α with respect to the tire axial direction and faces toward the tire axial direction outer side. 
     Thus, in a cross-section in the tire axial direction of the belt  30 , the resin-covered cord  32  is arrayed along the tire axial direction in an oblique overlapping state, such that the array directions of the reinforcing cords  36  lie substantially parallel to each other. In the cross-section in the tire axial direction of the belt  30 , the plural portions of the resin-covered cord  32  are stacked at an incline. In the belt  30 , the positions of respective corners (inner side corners in the tire radial direction)  32 E between the side face  32 A and the side face  32 C of the stacked resin-covered cord  32  preferably lie along a substantially straight line running parallel to the tire axial direction. 
     The joined portion  38  is configured by an overlapping portion between the side face  32 B of one location of the resin-covered cord  32  and the side face  32 A of another location of resin-covered cord  32  adjacent in the tire axial direction when the resin-covered cord  32  has been wound in a spiral pattern. In tire axial direction cross-section, a length c of the joined portion  38  is determined by the width a and the thickness b of the resin-covered cord  32 , as well as the angle of inclination α of the resin-covered cord  32  with respect to the tire axial direction. In the first exemplary embodiment, the angle of inclination α of the resin-covered cord  32  is set such that the length c of the joined portion  38  in tire axial direction cross-section is greater than the thickness b of the resin-covered cord  32  (c&gt;b, wherein, c=a−(b/tan α). 
     The belt  30  is joined to the outer circumference of the carcass ply  22  at the crown portion  18 . During joining of the belt  30  to the carcass ply  22 , the covering resin  34  of the resin-covered cord  32  is melted and pressed against the carcass ply  22  while being wound on in a spiral pattern. Thus, as illustrated in  FIG. 3 , in the belt  30  of the tire  10 , a space between the side face  32 C of the resin-covered cord  32  and the side face  32 A of the resin-covered cord  32  adjacent to this resin-covered cord  32 , and a space between the side face  32 D of the resin-covered cord  32  and the side face  32 B of the resin-covered cord  32  adjacent to this resin-covered cord  32 , are respectively filled by the molten covering resin  34 . A face at a carcass ply  22 -side and a face at a tread  20 -side of the belt  30  of the tire  10  are thus both configured with substantially flat profiles. 
     Operation 
     In the tire  10 , the belt  30  is joined to the outer circumference of the carcass ply  22  of the crown portion  18 , namely in the belt  30 , the resin-covered cord  32  that has been wound onto the outer circumference of the carcass ply  22  in a spiral pattern is melted and joined to the carcass ply  22 . 
     In the first exemplary embodiment, two of the reinforcing cords  36  are arrayed in the resin-covered cord  32 . The resin-covered cord  32  is inclined such that a length direction in the cross-section corresponding to the array direction of the reinforcing cords  36  is inclined with respect to the tire axial direction. In the belt  30 , mutually adjacent portions of the resin-covered cord  32  in the tire axial direction are welded together at the joined portion  38 . 
     Thus, in the resin-covered cord  32 , the length c of the joined portion  38  where adjacent portions of the resin-covered cord  32  are welded together is greater than the thickness b of the resin-covered cord  32  (c&gt;b), such that the resin-covered cord  32  has a wide contact surface area at the joined portion  38 . This improves the level of joining of the belt  30  in comparison to cases in which the length direction of the resin-covered cord  32  (the array direction of the reinforcing cords  36 ) is set along the tire axial direction. 
     Moreover, the belt  30  employs the resin-covered cord  32  in which the two reinforcing cords  36  are disposed, and the resin-covered cord  32  is wound on such that the array direction of the reinforcing cords  36  is inclined with respect to the tire axial direction. This enables the number of circuits of the resin-covered cord  32  in the tire axial direction, namely the number of reinforcing cords  36  in the belt  30 , to be increased in comparison to cases in which the array direction of the reinforcing cords  36  is set along the tire axial direction. In addition thereto, in the belt  30 , the resin-covered cord  32  in which the two reinforcing cords  36  are arrayed is wound on such that the array direction of the reinforcing cords  36  is inclined with respect to the tire axial direction. The reinforcing cords  36  are thus laid in two tiers, namely at the tire radial direction inner side and the tire radial direction outer side of the belt  30 . 
     This raises the in-plane shear rigidity of the belt  30  (in an annular plane extending in the tire circumferential direction and the tire width direction), enabling the steering stability afforded by the belt  30  when a vehicle travels on the tire  10  to be improved. 
     The belt  30  of the tire  10  is formed in this manner by winding the resin-covered cord  32  with the array direction of the reinforcing cords  36  inclined with respect to the tire axial direction when the belt  30  is laid on the outer circumference of the carcass ply  22 , thus improving the level of joining. The durability of the belt  30  is therefore improved, thus also improving the durability of the tire  10 . 
     Belt Manufacture 
     Next, explanation follows regarding manufacture of the annular belt  30 .  FIG. 4  is a schematic configuration diagram illustrating relevant portions in a manufacturing process of the belt  30  according to the first exemplary embodiment. 
     As illustrated in  FIG. 4  as an example, an annular (drum shaped) core  40  is employed in the manufacture of the belt  30 . An outer circumference of the core  40  configures a winding surface  40 A for the resin-covered cord  32 . The outer circumference (winding surface  40 A) of the core  40  is for example configured from metal. The outer circumference of the core  40  may have a linear cross-section profile or a curved cross-section profile along the axial direction, or may have a combination of a linear cross-section profile section and a curved cross-section profile section. 
     The outer circumference of the core  40  is divisible at plural circumferential direction locations, and each of the divided outer circumferential portions is capable of moving so as to retreat toward the radial direction inner side. This allows removal of the annular belt  30  formed on the outer circumference of the core  40  from the core  40 . 
     A support device (not illustrated in the drawings) that rotatably supports the core  40  is employed when winding the resin-covered cord  32  onto the outer circumference of the core  40 . The resin-covered cord  32  is wound using a cord supply device  50  that supplies the resin-covered cord  32  at the vicinity of the outer circumference of the core  40 , 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. 
     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  40  is formed in the guide member  54 . 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  40  while imparting the resin-covered cord  32  with a predetermined tension. 
     During manufacture of the belt  30 , the resin-covered cord  32  is fed onto the outer circumference of the core  40  by the cord supply device  50  while the core  40  is being rotated by the support device, such that the resin-covered cord  32  is wound onto the outer circumference of the core  40 . When this is performed, the core  40  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 cord  32  to be wound onto the outer circumference of the core  40  in a spiral pattern. Note that this relative movement between the core  40  and the opening  56  in the guide member  54  is for example performed by moving the core  40  along the tire axial direction. 
     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  is disposed so as to face between the resin-covered cord  32  already wound onto the core  40  and a core  40 -side face of the resin-covered cord  32  still being supplied to the core  40 . The heated airflow is blown against the resin-covered cord  32  through the blower outlet  62  of the heating device  60  so as to melt the covering resin  34 . 
     Note that 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 cord  32  to be wound onto the core  40  and the resin-covered cord  32  that has already been wound onto the core  40  against the outer circumference of the core  40  with a pressing force F. The cooling roller  72  is disposed further toward a rotation direction downstream side of the core  40  than the press roller  70 . The cooling roller  72  presses the resin-covered cord  32  that has been wound onto the outer circumference of the core  40  against the outer circumference of the core  40  following on from the press roller  70 . 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  when the roller surface of the cooling roller  72  contacts the resin-covered cord  32 . 
     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  40  (the arrow A direction) when pressed against the resin-covered cord  32 . 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. An outer circumferential portion of the press roller  70  is preferably capable of elastic deformation, and the pressing force F of the press roller  70  and the cooling roller  72  against the resin-covered cord  32  is preferably adjustable. 
     The resin-covered cord  32  that has been wound onto the core  40  and pressed by the press roller  70  is thus cooled by the cooling roller  72 . 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 cord  32 ) is allowed to cool naturally. 
     The resin-covered cord  32  of the belt  30  is inclined at the angle of inclination α when being wound onto the outer circumference of the core  40  in a spiral pattern. Where the resin-covered cord  32  freshly wound onto the outer circumference of the core  40  meets the resin-covered cord  32  that has already been wound onto the core  40 , the press roller  70  and the cooling roller  72  straddle between and press both the freshly wound resin-covered cord  32  and the adjacent resin-covered cord  32 . Namely, the press roller  70  and the cooling roller  72  are disposed so as to straddle between two corners of the resin covered cord  32  (corners between the respective side faces  32 B and side faces  32 D), namely a corner of the resin-covered cord  32  being wound onto the core  40  and a corner of the wound resin-covered cord  32  adjacent to this resin-covered cord  32 . By pressing against these two corners of the resin covered cord  32 , these two portions of the resin covered cord  32  are pressed against the core  40 . When this is performed, the outer circumferential portion of the press roller  70  undergoes elastic deformation, enabling the resin covered cord  32  to be pressed such that portions of the resin covered cord  32  on the opposite side to the core  40  become substantially flat. 
     Note that as an example, a lead cord  42  serving as a guiding member is employed when manufacturing the belt  30 . One or plural of the reinforcing cords  36  are provided in the lead cord  42 . The reinforcing cord(s)  36  in the lead cord  42  are covered by covering resin  34 . 
     One end side in a length direction of the lead cord  42  has a substantially triangular cross-section profile as sectioned along the tire axial direction. A face (upper base) of the lead cord  42  on the opposite side to the core  40  has a width dimension that increases on progression from the one length direction end side toward the other length direction end side, such that the lead cord  42  has a substantially trapezoidal cross-section profile along most of its length in the tire axial direction. The length of the lead cord  42  is substantially equivalent to the length of one circuit of the outer circumference of the core  40  (the length of one circuit of the belt  30  or very slightly shorter than this length), and a support face  42 A on the tire axial direction inner side of the lead cord  42  is inclined by the angle of inclination α with respect to the tire axial direction. 
     An end portion at the other end side in the length direction of the lead cord  42  has a profile combining the triangular profile of the leading end side and a part of the cross-section of the resin-covered cord  32  inclined at the angle of inclination α (a central portion of the resin-covered cord  32  cross-section excluding the corner  32 E and a corner on the opposite side to the corner  32 E, not illustrated in the drawings). 
     During manufacture of the belt  30 , first, the lead cord  42  is wound onto an axial direction end portion of the outer circumference of the core  40 . The position of the lead cord  42  on the belt  30  is a position on the carcass ply  22  of the tire  10  corresponding to one end side in the tire axial direction of the belt  30 . Note that although the lead cord  42  is employed as an example in the first exemplary embodiment, a leading end portion of the resin-covered cord  32  may be processed into a profile similar to that of the lead cord  42 . 
     During winding of the resin-covered cord  32  onto the outer circumference of the core  40 , the core  40  that is attached to the support device is rotated in the arrow A direction, and the resin-covered cord  32  is pulled out from the reel  52  of the cord supply device  50  and fed out through the opening  56  toward the outer circumference of the core  40 . As this is performed, a leading end of the resin-covered cord  32  is pressed against a trailing end of the lead cord  42 , and the side face  32 A of the leading end portion of the resin-covered cord  32  is overlaid on the support face  42 A of the lead cord  42 . The resin-covered cord  32  is thus wrapped onto the outer circumference of the core  40  in a spiral pattern with the side face  32 A inclined at the angle of inclination α with respect to the rotation axis of the core  40 . 
     In addition, the heated airflow is blown out through the blower outlet  62  of the heating device  60  so as to heat the side face  32 B of the resin-covered cord  32  wound onto the core  40  (the support face  42 A of the lead cord  42  initially) and the side face  32 A of the resin-covered cord  32  being freshly wound onto the core  40 . While the covering resin  34  is being melted, the resin-covered cord  32  being freshly wound onto the core  40  and the resin-covered cord  32  adjacent to this resin-covered cord  32  (already wound onto the core  40 ) are pressed by the press roller  70 . When this is performed, the cord supply device  50  imparts tension to the resin-covered cord  32 , which is fed from the cord supply device  50  to the outer circumference of the core  40 , in order to suppress slippage of the resin-covered cord  32  in an axial direction of the core  40 . 
     The resin-covered cord  32  is thus wound onto the outer circumference of the core  40  in a spiral pattern in a state in which the array direction of the reinforcing cords  36  is inclined by the angle of inclination α with respect to the outer circumference of the core  40  (the axial direction of the core  40 ). The heated airflow from the blower outlet  62  of the heating device  60  is blown between side faces of the resin-covered cord  32  as they are being wound onto the core  40  so as to melt the covering resin  34  and weld the resin covered cord  32  together at the joined portion  38 . 
     Moreover, the molten covering resin  34  of the resin-covered cord  32  is pressed at the pressing force F by the press roller  70  at a portion contacted by the press roller  70  and a portion on the side of the core  40 . Thus, in the resin-covered cord  32  that has been wound onto the outer circumference of the core  40 , the covering resin  34  is melted at a corner on the side of the outer circumference of the core  40  (the corner  32 E) and a corner on the opposite side to the outer circumference of the core  40 , such that a gap between the covering resin  34  and the outer circumference of the core  40  and a gap between the covering resin  34  and the press roller  70  are filled by the molten covering resin  34 . A face of the belt  30  on the side of the outer circumference of the core  40  and a face of the belt  30  on the opposite side to the outer circumference of the core  40  are thus both formed substantially flat. 
     The resin-covered cord  32  is then cooled and set by pressing with the cooling roller  72 . The belt  30  is accordingly manufactured by winding the resin-covered cord  32  onto the outer circumference of the core  40  in a spiral pattern in this manner. The manufactured belt  30  is then removed from the core  40  and pressure-welded to the outer circumference of the carcass ply  22  in a vulcanization process or the like to manufacture the tire  10 . 
     In the manufactured belt  30 , the array direction of the reinforcing cords  36  is inclined at the fixed angle of inclination α with respect to the tire axial direction such that the resin-covered cord  32  overlaps itself in the tire axial direction, and adjacent portions of the resin covered cord  32  are welded together at the joined portion  38 . 
     Note that during manufacture of the belt  30 , the tension of the resin-covered cord  32  supplied to the core  40  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 cord  32 , or the like. This enables snaking or the like of the resin-covered cord  32  as it is being wound onto the core  40  to be suppressed, enabling a high quality belt  30  to be manufactured in which the resin-covered cord  32  is wound on in a spiral pattern at a uniform pitch. 
     Although the core  40  is employed during manufacture of the belt  30 , the carcass ply  22  may be employed instead of the core  40 , such that the belt  30  is manufactured by winding the resin-covered cord  32  onto the outer circumference of the carcass ply  22  in a spiral pattern. In such cases, the carcass ply  22  is attached to a support device, and the resin-covered cord  32  is wound onto the outer circumference of the carcass ply  22  in a spiral pattern while rotating the carcass ply  22 . This enables the belt  30  to be manufactured while joining the resin-covered cord  32  to the outer circumference of the carcass ply  22 . 
     Note that the joining properties of the resin-covered cord  32  at the joined portion  38  are affected by the weld strength of the covering resin  34  at the joined portion  38 . The weld strength is affected by the contact surface area of the resin-covered cord  32  at the joined portion  38 , and by a pressing force F′ (see  FIG. 2 ) acting perpendicularly to contacting faces (side faces  32 A,  32 B) at the joined portion  38  (for example, weld strength=contact surface area×pressing force). 
     In the belt  30 , the resin-covered cord  32  is inclined at the angle of inclination α, such that the length c of the joined portion  38  along the width direction of the resin-covered cord  32  is longer than the thickness b, and the contact surface area is larger than it would be in a case in which the side faces  32 C,  32 D were welded together, thereby improving the weld strength. 
     During manufacture of the belt  30 , when the resin-covered cord  32  is pressed against the core  40  at the pressing force F (see  FIG. 2 ), a pressing force F′ acting perpendicularly to the contacting faces (side faces  32 A,  32 B) at the joined portion  38  is F′=cos α. The contact surface area of the resin-covered cord  32  is determined by the length c of the joined portion  38 . A weld strength of the resin-covered cord  32  may be expressed as below. 
       weld strength=( a −( b /tan α))· F ·cos α
 
     Thus, increasing the pressing force F enables the weld strength to be improved proportionately to the pressing force F, thereby enabling joining properties of the resin-covered cord  32  to be improved. 
     When a weld ratio Rw is defined as a proportion (ratio) of the weld strength of the joined portion  38  with respect to the pressing force F during manufacture of the belt  30 , the weld ratio Rw may be obtained as below. 
         Rw =( a −( b /tan α))·cos α
 
     Increasing the weld ratio Rw enables the weld strength of the resin-covered cord  32  to be effectively improved. 
     Table 1 illustrates changes in the weld ratio Rw with respect to the angle of inclination α.  FIG. 5  is a line graph illustrating changes in the weld ratio Rw with respect to the angle of inclination α based on Table 1. In Table 1, a resin-covered cord  32  with width a=5 mm and thickness b=2 mm is applied as an example. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Angle of inclination 
                   
               
            
           
           
               
               
               
            
               
                 α (deg) 
                 α (rad) 
                 Weld ratio (Rw) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 0.0 
                 0.0 
                   
               
               
                 5.0 
                 0.1 
               
               
                 10.0 
                 0.2 
               
               
                 15.0 
                 0.3 
               
               
                 20.0 
                 0.3 
               
               
                 25.0 
                 0.4 
                 0.6 
               
               
                 30.0 
                 0.5 
                 1.3 
               
               
                 35.0 
                 0.6 
                 1.8 
               
               
                 40.0 
                 0.7 
                 2.0 
               
               
                 45.0 
                 0.8 
                 2.1 
               
               
                 50.0 
                 0.9 
                 2.1 
               
               
                 55.0 
                 1.0 
                 2.1 
               
               
                 60.0 
                 1.0 
                 1.9 
               
               
                 65.0 
                 1.1 
                 1.7 
               
               
                 70.0 
                 1.2 
                 1.5 
               
               
                 75.0 
                 1.3 
                 1.2 
               
               
                 80.0 
                 1.4 
                 0.8 
               
               
                 85.0 
                 1.5 
                 0.4 
               
               
                 90.0 
                 1.6 
                 0.0 
               
               
                   
               
            
           
         
       
     
     As illustrated in Table 1 and in  FIG. 5 , the weld ratio Rw never falls below 1.3 in a range in which the angle of inclination α is between 30° and 70° (30°≤α≤70°), and so the weld strength at the joined portion  38  is effectively improved in accordance with the pressing force F, and the joining properties of the resin-covered cord  32  are improved. 
     When the resin-covered cord  32  is overlaid on itself at the joined portion  38 , a contact surface area of the resin-covered cord  32  can be increased by making the length c greater than the thickness b of the resin-covered cord  32 . For example, in order to make the length c of the joined portion  38  greater than the thickness b in a case in which the resin-covered cord  32  has width a=5 mm and thickness b=2 mm, then α&gt;33.7° (wherein tan −1  (α)&gt;(b/(a−b)). In this example, setting the angle of inclination α between 33.7° and 70° enables the joining properties of the resin-covered cord  32  of the belt  30  to be effectively improved, thus enabling a high level of joining to be obtained. 
     The joining properties of the resin-covered cord  32  of the belt  30  can thus be improved by setting the angle of inclination α such that the length c of the joined portion  38  is greater (longer) than the thickness b of the resin-covered cord  32 . In addition, by setting the angle of inclination α in the belt  30  from 30° to 70°, weld strength of the resin-covered cord  32  can be effectively improved, joining properties of the resin-covered cord  32  can be effectively improved, and the durability of the tire  10  can be effectively improved. 
     Second Exemplary Embodiment 
     Next, explanation follows regarding a second exemplary embodiment.  FIG. 6  is a cross-section illustrating relevant portions of a belt  80  according to the second exemplary embodiment, sectioned along a direction corresponding to the tire axial direction. The belt  80  of the second exemplary embodiment is employed in the tire  10  in place of the belt  30  of the first exemplary embodiment, and is laid at the outer circumference of the carcass ply  22  of the tire  10 . 
     As illustrated in  FIG. 6 , a resin-covered cord  82  is employed in the belt  80  in place of the resin-covered cord  32  of the first exemplary embodiment. The belt  80  is formed by winding the resin-covered cord  82  in a spiral pattern. 
     Plural reinforcing cords  36  are arrayed in the resin-covered cord  82 . In the second exemplary embodiment, two of the reinforcing cords  36  are employed as an example, and the reinforcing cords  36  are covered by covering resin  34 . In cross-section profile sectioned along a direction corresponding to the tire axial direction, the resin-covered cord  82  has an elongated rectangular profile in which at least a pair of side faces  82 A,  82 B running in an array direction of the reinforcing cords  36  are substantially parallel to each other, and the lengths of the side faces  82 A,  82 B are longer than the lengths of other side faces  82 C,  82 D. 
     When being wound in a spiral pattern, the array direction of the reinforcing cords  36  in the resin-covered cord  82  is inclined by an acute angle of inclination α with respect to the tire axial direction. Specifically, in the resin-covered cord  82 , one out of the side faces  82 A,  82 B (for example the side face  82 A) that run along the array direction of the reinforcing cords  36  faces toward the tire radial direction inner side, and this side face  82 A is inclined by the angle of inclination α with respect to the tire axial direction and faces toward the tire axial direction outer side. 
     Note that the resin-covered cord  82  is formed such that an obtuse angle θ between the one side face  82 A and the side face  82 C adjacent to this side face  82 A is a supplementary angle of the angle of inclination α (acute angle α) (namely, α+β=180°). Note that although the resin-covered cord  82  has a parallelogram shaped cross-section profile and an obtuse angle between the side face  82 B and the side face  82 D is the same as the angle β in the second exemplary embodiment, the angle between the side face  82 B and the side face  82 D may be different from the angle β. Moreover, the lengths of the side face  82 A and the side face  82 B of the resin-covered cord  82  may be different from each other. 
     In the belt  80  employing the resin-covered cord  82  configured in this manner, the resin-covered cord  82  is wound in a spiral pattern such that the side face  82 A is tilted by the angle of inclination α with respect to the tire axial direction. Thus, in the belt  80 , the side face  82 C of the resin-covered cord  82  forms a contiguously extending substantially straight line, and the side face  82 B of the resin-covered cord  82  contacts the side face  82 A at adjacent portions of the resin-covered cord  82 . 
     Thus, the side faces  82 C,  82 D of the resin-covered cord  82  of the belt  80  both form substantially straight lines (are substantially flat), and the task of winding the resin-covered cord  82  in a spiral pattern with the array direction of the reinforcing cords  36  inclined with respect to the tire axial direction is facilitated. Moreover, since the tire radial direction inner side of the belt  80  is substantially flat, the joining properties and the level of joining of the belt  80  can be improved, facilitating joining to the carcass ply  22 . 
     Moreover, in the belt  80 , substantially the entire surface of the side face  82 B of the resin-covered cord  82  overlaps with the adjacent side face  82 A of the resin-covered cord  82  to form a joined portion  84 . This enables the joining surface area (surface area of the joined portion  84 ) between adjacent portions of the resin covered cord  82  of the belt  80  to be increased, enabling the joining properties to be improved, and enabling the level of joining of the resin-covered cord  82  to be improved. Moreover, the resin-covered cord  82  is inclined at the angle of inclination α, and by setting the angle of inclination α from 30° to 70°, the weld strength of the resin-covered cord  82  can be effectively improved, and the resin-covered cord  82  joining properties can be effectively improved. This enables the durability of the belt  80  that employs the resin-covered cord  82  to be improved, thereby enabling the durability of the tire  10  provided with the belt  80  to be improved. 
     The entire content of the disclosure of Japanese Patent Application No. 2018-116393 filed on Jun. 20, 2018 is incorporated by reference in the present specification. 
     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.