Tire and method for manufacturing tire

Abstract

This tire comprises: a resin tire skeleton member having bead portions, side portions that are continuous with the tire-radial-direction outer sides of the bead portions, and a crown portion that is continuous with the tire-width-direction inner sides of the side portions; and a tread disposed on the tire-radial-direction outer side of the crown portion. The crown portion includes: a belt layer in which one or a plurality of reinforcement cords are resin-coated; and a resin layer disposed on the tire-radial-direction outer side of the belt layer. A portion of the tread is in contact with the outer peripheral surface of the belt layer.

Description

Tire and tire manufacturing method

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to tires and methods for manufacturing tires.

[0002] Japanese Patent No. 6306564 discloses a tire having a tire frame member made of resin, in which a belt layer including resin-coated cords, in which reinforcing cords are resin-coated, and a rubber tread are arranged on the radially outer side of a crown portion of the tire frame member.

[0003] In the tire disclosed in Japanese Patent No. 6306564, the interface between the belt layer and the rubber tread is linear along the tire width direction, so when a shear force in the tire width direction is applied to the interface between the rubber tread and the belt layer, there is a risk that the interface will peel or the peeled portion will progress.

[0004] The present disclosure aims to suppress tread peeling in a tire having tire frame members made of resin.

[0005] A tire according to one aspect of the present disclosure comprises a tire frame member made of resin, the tire frame member having a bead portion, a side portion connected to the radially outer side of the bead portion, and a crown portion connected to the radially inner side of the side portion, and a tread disposed radially outward of the crown portion, the crown portion including a belt layer having one or more reinforcing cords resin-coated therein, and a resin layer disposed radially outward of the belt layer, and a portion of the tread being in contact with the outer peripheral surface of the belt layer.

[0006] A tire manufacturing method according to another aspect of the present disclosure includes the steps of: setting a belt having one or more resin-coated reinforcing cords and a vulcanized or semi-vulcanized tread in a cavity formed by a tire molding mold, with a portion of the tread in contact with the belt so that a gap is formed between them; and injecting molten resin into the cavity to mold a tire frame member having bead portions, side portions connected to the bead portions radially outward in the tire direction, and a crown portion connected to the side portions radially inward in the tire width direction.

[0007] According to the present disclosure, tread peeling can be suppressed in a tire having a tire frame member made of resin.

[0008] 7A is a cross-sectional view of a tire according to an embodiment of the present disclosure, taken along the tire width direction; FIG. 1 is an enlarged view of a portion indicated by arrow 2X in FIG. 1; FIG. 3A is an enlarged view of a portion indicated by arrow 3X in FIG. 1; FIG. 1B is a side view of a portion of the rubber chafer shown in FIG. 1, as seen from the inside of the tire; FIG. 1C is a cross-sectional view of a bead portion at a support portion of the rubber chafer shown in FIG. 1, taken along the tire width direction; FIG. 1D is a cross-sectional view of the periphery of a through-hole in the tread shown in FIG. 1, taken along the tire width direction; FIG. 1E is a cross-sectional view of the tread shown in FIG. 1; FIG. 1F is a plan view of the inner peripheral surface of the tread shown in FIG. 7A; FIG. 1G is a cross-sectional view of a tire molding mold for molding the tire shown in FIG. 1; FIG. 1H is a cross-sectional view of a tire molding mold in a state in which a tread, a belt, a bead core, and a rubber chafer are set in the cavity of the tire molding mold shown in FIG. 8; FIG. 1H is an enlarged view of a portion indicated by arrow 10X in FIG. 9; FIG. 1J is a cross-sectional view of a tire molding mold showing the periphery of a through-hole in the tread set in the cavity; FIG. 1J is a cross-sectional view of a tire molding mold showing a state in which the resin filled in the cavity has solidified; FIG. 1J is a cross-sectional view of a tire according to another embodiment of the present disclosure, taken along the tire width direction; FIG. 1J is an enlarged view of a portion indicated by arrow 14X in FIG.

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of each element shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.

[0010] In the drawings, arrow TC indicates the tire circumferential direction, arrow TW indicates the tire width direction, and arrow TR indicates the tire radial direction. Hereinafter, the side closer to the tire rotation axis along the tire radial direction will be referred to as the "tire radially inner side," and the side farther from the tire rotation axis along the tire radial direction will be referred to as the "tire radially outer side." Meanwhile, the side closer to the tire equatorial plane CL along the tire width direction will be referred to as the "tire widthwise inner side," and the side farther from the tire equatorial plane CL along the tire width direction will be referred to as the "tire widthwise outer side." The measurement method for each part follows the method described in the 2023 YEAR BOOK published by JATMA (Japan Automobile Tire Manufacturers Association).

[0011] As shown in FIG. 1, the tire 10 of this embodiment is, as an example, a pneumatic tire that is mounted on a standard rim (not shown) and filled with air, and has a cross-sectional shape that is substantially the same as that of a conventional pneumatic tire made of rubber (hereinafter referred to as a "rubber tire" as appropriate).

[0012] [Tire Frame Member 18 ] The tire 10 of this embodiment has an annular tire frame member 18 made of resin, which serves as a frame portion of the tire 10 .

[0013] The tire frame member 18 includes a pair of bead portions 12 spaced apart in the tire width direction, side portions 14 connected to the tire radially outer sides of the bead portions 12, and a crown portion 16 connected to the tire widthwise inner sides of the side portions 14 and connecting the tire radially outer ends of each side portion 14. The circumferential direction, width direction, and radial direction of the tire frame member 18 correspond to the tire circumferential direction, tire axial direction, and tire radial direction, respectively.

[0014] The tire frame member 18 is mainly formed of a thermoplastic resin 19. Details of this thermoplastic resin 19 will be described later.

[0015] (Bead Portion 12) As shown in Figure 3, the bead portion 12 is a portion that fits onto a standard rim (not shown) via a rubber chafer 26. An annular bead core 20 extending along the tire circumferential direction is embedded inside this bead portion 12. The bead core 20 is formed by coating a bead cord 22 made of a metal (e.g., steel), organic fiber, or the like that is wound into an annular shape with a thermoplastic resin 24. Details of this thermoplastic resin 24 will be described later.

[0016] - Rubber chafer 26 - The rubber chafer 26 is disposed on the outer side of the bead portion 12 in the tire width direction. Specifically, the rubber chafer 26 is disposed on the outer side surface of the bead portion 12 in the tire width direction and the inner side surface in the tire radial direction, which are in contact with a standard rim (not shown). The rubber chafer 26 is formed of vulcanized rubber (rubber that has been vulcanized) and is joined to the bead portion 12. Specifically, the outer surface of the bead portion 12 (including the outer side surface of the bead portion 12 in the tire width direction and the inner side surface in the tire radial direction) and the inner surface of the rubber chafer 26 are bonded together. The bonding between the outer surface of the bead portion 12 and the inner surface of the rubber chafer 26 will be described in detail below.

[0017] A portion of the rubber chafer 26 is in contact with the bead core 20 embedded in the bead portion 12. As shown in Figures 3 and 5, a contact portion 27 of the rubber chafer 26 is a portion that protrudes from an inner surface 26A of the rubber chafer 26 in the tire width direction toward the bead core 20. As shown in Figure 4, a plurality of contact portions 27 are provided at intervals in the tire circumferential direction. Note that the contact portions 27 are preferably arranged at equal intervals in the tire circumferential direction.

[0018] As shown in FIGS. 3 and 5, the contact portion 27 supports the bead core 20 from the outer side in the tire width direction.

[0019] 1, the side portion 14 is a portion that constitutes a side portion of the tire 10. The side portion 14 is gently curved from the bead portion 12 toward the crown portion 16 so as to be convex outward in the tire width direction.

[0020] As shown in Fig. 5, the thickness of the side portion 14 increases in a portion corresponding to the end 26B of the rubber chafer 26 on the outer side in the tire radial direction. Specifically, the thickness of the side portion 14 is constant from the portion on the crown portion 16 side to the vicinity of the portion corresponding to the end 26B of the rubber chafer 26, and increases in the portion corresponding to the end 26B of the rubber chafer 26. Therefore, a step is formed on the outer surface of the side portion 14 in front of the portion corresponding to the end 26B of the rubber chafer 26 (outside in the tire radial direction) due to the increase in thickness. Note that in this embodiment, the portion of the side portion 14 corresponding to the end 26B of the rubber chafer 26 is the portion of the side portion 14 on the bead portion 12 side.

[0021] (Crown portion 16) As shown in Fig. 1, the crown portion 16 is a portion that supports a tread 34 (described later) disposed radially outward in the tire. In this embodiment, the outer peripheral surface of the crown portion 16 is formed flat along the tire width direction. Note that the symbol CW in Fig. 1 indicates the width of the crown portion 16 along the tire width direction.

[0022] The crown portion 16 includes a belt layer 28 in which one or more reinforcement cords 30 are resin-coated. The crown portion 16 also includes a resin layer 29 arranged radially outward of the belt layer 28. In the present embodiment, as an example, the crown portion 16 has a two-layer structure, with the belt layer 28 constituting the inner layer (the layer on the inner side in the tire radial direction) of the crown portion 16 and the resin layer 29 constituting the outer layer (the layer on the outer side in the tire radial direction) of the crown portion 16. Therefore, in the tire 10 of the present embodiment, the inner circumferential surface of the belt layer 28 constitutes the inner circumferential surface of the crown portion 16, and the outer circumferential surface of the resin layer 29 constitutes the outer circumferential surface of the crown portion 16. Note that, in the tire 10 of the present embodiment, it is sufficient that at least a portion of the inner circumferential surface of the belt layer 28 constitutes the inner circumferential surface of the crown portion 16. For example, it is more preferable that 80% or more of the inner circumferential surface of the belt layer 28 constitutes the inner circumferential surface of the crown portion 16, and it is even more preferable that 100% of the inner circumferential surface of the belt layer 28, i.e., the entire inner circumferential surface, constitutes the inner circumferential surface of the crown portion 16. In the present embodiment, as an example, the entire inner circumferential surface of the belt layer 28 constitutes the inner circumferential surface of the crown portion 16.

[0023] - Belt layer 28 - As shown in Fig. 1 , the belt layer 28 is formed by spirally winding a coated cord in the tire circumferential direction, the coated cord being one or more reinforcement cords 30 coated with a thermoplastic resin 32. In other words, the belt layer 28 is formed by coating annularly wound reinforcement cords 30 made of metal (e.g., steel), organic fiber, or the like with the thermoplastic resin 32. In the present embodiment, as an example, the belt layer 28 is formed by spirally winding a coated cord in the tire circumferential direction, the coated cord being two reinforcement cords 30 coated with the thermoplastic resin 32 (see Fig. 2 ). Details of the thermoplastic resin 32 used in the belt layer 28 will be described later.

[0024] The belt layer 28 of the present embodiment has, for example, a cylindrical shape with a constant diameter.

[0025] 1 , the range from the end 28A of the belt layer 28 on the outer side in the tire width direction to the side portion 14 is formed only from the thermoplastic resin 19. Specifically, the range from the end 28A of the belt layer 28 to the end of the side portion 14 on the inner side in the tire radial direction is formed only from the thermoplastic resin 19.

[0026] 1, the resin layer 29 is made of only a resin. Specifically, the resin layer 29 is made of a single resin. In the present embodiment, as an example, the resin layer 29 is made of only a thermoplastic resin 19.

[0027] The resin layer 29 is also bonded to the tread 34. Specifically, the outer peripheral surface of the tire frame member 18, including the outer peripheral surface of the resin layer 29, is bonded to the inner peripheral surface of the tread 34. The bonding between the outer peripheral surface of the tire frame member 18 and the inner peripheral surface of the tread 34 will be described in detail later.

[0028] The belt layer 28 and the resin layer 29 are welded together. Specifically, the outer peripheral surface of the belt layer 28 and the inner peripheral surface of the resin layer 29 are welded together. More specifically, the thermoplastic resin 32 constituting the belt layer 28 and the thermoplastic resin 19 constituting the resin layer 29 are welded together. In the present embodiment, as an example, the thermoplastic resin 32 and the thermoplastic resin 19 are the same type of resin, more specifically, resins having the same components, but they may be different types of resins.

[0029] 1 , a tread 34 made of vulcanized rubber (rubber that has been vulcanized) is disposed on the tire radially outer side of the crown portion 16 of the tire frame member 18. The inner circumferential surface of the tread 34 is joined to the outer circumferential surface of the tire frame member 18, including the crown portion 16.

[0030] A tread pattern (not shown) is formed on the outer peripheral surface of the tread 34 at the contact surface with the road surface.

[0031] The inner peripheral surface of the tread 34 is flat. As shown in Figures 1 and 2, the inner peripheral surface of the tread 34 is provided with a plurality of protrusions 35 that protrude toward the outer peripheral surface of the belt layer 28. The plurality of protrusions 35 penetrate the resin layer 29. The tips of the protrusions 35 are in contact with the outer peripheral surface of the belt layer 28. That is, in this embodiment, the protrusions 35, which are part of the tread 34, are in contact with the outer peripheral surface of the belt layer 28.

[0032] The plurality of protrusions 35 are formed to a constant height so as to maintain a constant distance between the tread 34 and the belt layer 28. The height of the protrusions 35 is preferably set so that molten resin can easily move between the tread 34 and the belt layer 28 during tire molding.

[0033] 7A and 7B , the multiple protrusions 35 are provided at intervals in the tire circumferential direction and the tire width direction. The multiple protrusions 35 are preferably provided at equal intervals in the tire circumferential direction. The multiple protrusions 35 are preferably provided at equal intervals in the tire width direction. In this embodiment, as an example, the tire circumferential positions of the protrusions 35 located on both end sides of the tread 34 in the tire width direction are offset from the tire circumferential positions of the protrusions 35 located on the center side in the tire width direction. Specifically, the protrusions 35 located on both end sides of the tread 34 in the tire width direction are located at the center between the protrusions 35 located on the center side in the tire width direction.

[0034] As shown in FIG. 7B , the tread 34 is provided with a plurality of through holes 36 penetrating in the tire radial direction. These through holes 36 are provided in the tread 34 at intervals in the tire circumferential direction. These through holes 36 are used, for example, as gas vent holes during tire molding. A plurality of through holes 36 may be formed along the injection direction of molten resin from a gate 46 of a mold 40 (described later). In FIG. 7B , as an example, three through holes 36 are formed at equal intervals in the injection direction of molten resin from the gate 46. Of the three through holes 36, two are formed on one side of the tire circumferential direction and two are formed on the other side, equally spaced from the through hole 36 on the center line of the tread 34. In this embodiment, the center line of the tread 34 coincides with the tire equatorial plane CL, and is therefore denoted by the symbol CL in FIGS. 7A and 7B . The positions of the through holes 36 formed in the tread 34 are not limited to those described above. They are preferably set at optimal positions depending on the position of the gate 46 for molten resin, the injection pressure, and the like.

[0035] The plurality of through holes 36 are each filled with the thermoplastic resin 19 that forms the resin layer 29. The thermoplastic resin 19 that fills the through holes 36 protrudes from the outer peripheral surface of the resin layer 29. In other words, the molten thermoplastic resin 19 that forms the resin layer 29 during tire formation enters the through holes 36, and the through holes 36 are filled with the thermoplastic resin 19 after the resin has solidified.

[0036] As shown in Figure 2, in the tire 10 of this embodiment, the resin thickness dimension t1 between the tread 34 and the reinforcing cord 30 is thicker than the resin thickness dimension t2 between the inner surface of the crown portion 16 and the reinforcing cord 30.

[0037] As described above, in the tire 10 of this embodiment, the range from the outer end 28A of the belt layer 28 in the tire width direction to the inner end of the side portion 14 in the tire radial direction is formed only from the thermoplastic resin 19. When the thickness of the thermoplastic resin 19 in the above range of the tire frame member 18 is T (see FIG. 1 ), the product of the thickness T and the elastic modulus of the thermoplastic resin 19 is preferably set to 200 MPa mm or more and 600 MPa mm or less, and more preferably set to 250 MPa mm or more and 450 MPa mm or less.

[0038] Next, the thermoplastic resin 19 used in the tire frame member 18, the thermoplastic resin 24 used in the bead core 20, and the thermoplastic resin 32 used in the belt layer 28 will be described below.

[0039] Thermoplastic resins (including thermoplastic elastomers) are polymeric compounds that soften and flow as the temperature rises, and become relatively hard and strong when cooled.

[0040] In this specification, a distinction is made between thermoplastic elastomers, which are polymeric compounds that soften and flow with increasing temperature, become relatively hard and strong when cooled, and have rubber-like elasticity, and non-elastomer thermoplastic resins, which are polymeric compounds that soften and flow with increasing temperature, become relatively hard and strong when cooled, and do not have rubber-like elasticity.

[0041] Examples of thermoplastic resins (including thermoplastic elastomers) include polyolefin thermoplastic elastomers (TPO), polystyrene thermoplastic elastomers (TPS), polyamide thermoplastic elastomers (TPA), polyurethane thermoplastic elastomers (TPU), polyester thermoplastic elastomers (TPC), and dynamically crosslinked thermoplastic elastomers (TPV), as well as polyolefin thermoplastic resins, polystyrene thermoplastic resins, polyamide thermoplastic resins, and polyester thermoplastic resins.

[0042] The thermoplastic resin may have, for example, a deflection temperature under load (at a load of 0.45 MPa) of 78°C or higher as specified in ISO 75-2 or ASTM D648, a tensile yield strength of 10 MPa or higher as specified in JIS K7113, a tensile elongation at break of 50% or higher as specified in JIS K7113, and a Vicat softening temperature (method A) of 130°C as specified in JIS K7206. Note that a polyester resin may be used instead of the polyester thermoplastic elastomer (TPC).

[0043] In this embodiment, the thermoplastic resin 19, the thermoplastic resin 24, and the thermoplastic resin 32 are made of a polyester thermoplastic elastomer (TPC).

[0044] Next, a method for manufacturing a tire according to this embodiment will be described. First, a mold 40 used for manufacturing the tire will be described.

[0045] [Mold] Figure 8 shows a cross-sectional view of a mold 40 as an example of a tire molding die for molding the tire 10 of this embodiment. The mold 40 includes an outer mold 42 for molding the outer surface side of the tire, and an inner mold (in other words, a core) 44 for molding the inner surface side of the tire. A cavity S (space) for molding the tire 10 is formed between the outer mold 42 and the inner mold 44. The arrows TW and TR shown in Figures 8 to 12 indicate the tire width direction and tire radial direction of the tire 10 molded by the mold 40.

[0046] The outer mold 42 includes a first mold 42A that molds the outer peripheral side of the tire, and a pair of second molds 42B that mold the side portions of the tire.

[0047] The first mold 42A is composed of a plurality of blocks divided into blocks in the tire circumferential direction of the tire 10 to be molded by the mold 40. Note that Figs. 8, 9, and 12 show a cross section of one block constituting the first mold 42A. As shown in Fig. 8, each block is configured to be movable in the tire radial direction. Specifically, each block is configured to be movable in the tire radial direction, i.e., in the direction approaching and moving away from the inner mold 44. Note that the direction in which each block approaches the inner mold 44 is also referred to as the mold closing direction of the first mold 42A, and the direction in which each block moves away from the inner mold 44 is also referred to as the mold opening direction of the first mold 42A.

[0048] The pair of second dies 42B are configured to be movable in the tire width direction. Specifically, as shown in Fig. 8 , the pair of second dies 42B are configured to be movable in the tire width direction, i.e., in directions approaching and moving away from the inner die 44. The direction in which the second dies 42B approach the inner die 44 is also referred to as the die clamping direction of the second die 42B, and the direction in which the second dies 42B move away from the inner die 44 is also referred to as the die opening direction of the second die 42B.

[0049] The first die 42A of the outer mold 42 has gates 46 provided in the cavity S at positions on both outer sides in the tire width direction of the tread 34 for injecting molten resin into the cavity S. Specifically, each block constituting the first die 42A has a gate 46. Note that one pair of gates 46 on both outer sides in the tire width direction may be provided in one block, or multiple pairs spaced apart in the tire circumferential direction.

[0050] The inner mold 44 is provided with protruding holding portions 48 that hold the bead cores 20. Specifically, the holding portions 48 protrude from the inner mold 44, and recesses 48A into which the bead cores 20 fit are formed at the protruding tips. The bead cores 20 are held by fitting into these recesses 48A. Furthermore, a plurality of holding portions 48 are provided on the inner mold 44 at intervals in the circumferential direction (the same direction as the tire circumferential direction). It is preferable that the holding portions 48 be provided on the inner mold 44 at equal intervals.

[0051] [Tire Manufacturing Method] Next, a manufacturing process of the tire 10 of this embodiment will be described.

[0052] First, the tread 34, the belt layer 28, the rubber chafer 26, and the bead core 20 that constitute the tire 10 are prepared.

[0053] In the present embodiment, as an example, the tread 34 and the rubber chafer 26 are formed of vulcanized rubber. Note that the tread 34 and the rubber chafer 26 may be formed of semi-vulcanized rubber. In this case, the tread 34 and the rubber chafer 26 may be vulcanized after the tire frame member 18 is molded. Note that the belt layer 28 is an example of a belt in the present disclosure.

[0054] The tread 34 used in this embodiment is subjected to a primer treatment with a chlorine compound at the portion that comes into contact with the molten thermoplastic resin 19 .

[0055] Furthermore, the rubber chafer 26 used in this embodiment is subjected to a primer treatment with a chlorine compound at the portion that comes into contact with the molten thermoplastic resin 19 .

[0056] Next, as shown in FIG. 9 , the tread 34, the belt layer 28, the rubber chafers 26, and the bead cores 20 are placed at predetermined positions in the cavity S of the mold 40. Specifically, the tread 34 and the belt layer 28 are set in the cavity S so that a gap is formed between the tread 34 and the belt layer 28. More specifically, the tread 34 is set with a portion of the tread 34 in contact with the belt layer 28 so that a gap is formed between the tread 34 and the belt layer 28. In the present embodiment, as an example, the tread 34 and the belt layer 28 are set in the cavity S with the tips of the multiple protrusions 35 of the tread 34 in contact with the outer peripheral surface of the belt layer 28. This ensures a gap between the tread 34 and the belt layer 28. Note that, as a method for setting the tread 34 and the belt layer 28 in the cavity S, there is a method in which the tread 34 is held by the first mold 42A, the belt layer 28 is held by the inner mold 44, and the first mold 42A is then closed to set the tread 34 and the belt layer 28 in the cavity S. Note that the present disclosure is not limited to this setting method, and for example, the tread 34 and the belt layer 28 may be set in the cavity S by holding the belt layer 28 in the inner mold 44 and closing the first mold 42A in a state in which the tread 34 is held by bringing the tips of the multiple protrusions 35 into contact with the outer peripheral surface of the belt layer 28, or another method may be used.

[0057] 10 , the bead core 20 is fitted into and held in the recesses 48A of the multiple holding portions 48. Then, the rubber chafer 26 and the bead core 20 are set in the cavity S with a portion of the rubber chafer 26 in contact with the bead core 20 from the side opposite the multiple holding portions 48. Specifically, the rubber chafer 26 and the bead core 20 are set in the cavity S with the bead core 20 sandwiched and held between the multiple holding portions 48 and the contact portion 27 of the rubber chafer 26 in the clamping direction of the second mold 42B. One method for setting the bead core 20 and the rubber chafer 26 in the cavity S is to hold the bead core 20 with the multiple holding portions 48 of the inner mold 44, and clamp the pair of second molds 42B with the rubber chafer 26 held therein, thereby setting the bead core 20 and the rubber chafer 26 in the cavity S. Note that the present disclosure is not limited to this setting method.

[0058] Next, molten thermoplastic resin 19 for forming the tire frame member 18 is injected from multiple gates 46 into the cavity S in which the tread 34, belt layer 28, rubber chafer 26, and bead core 20 are set. Specifically, the molten thermoplastic resin 19 is injected into the cavity S from both outer sides of the tread 34 in the tire width direction. When the thermoplastic resin 19 is injected into the cavity S from each gate 46, gas is generated. The generated gas is discharged from the through holes 36 formed in the tread 34, as shown in FIG. 11 . Note that while the molten thermoplastic resin 19 is filling the cavity S due to injection pressure, some of it enters and fills the through holes 36. This fills the through holes 36 in the tread 34.

[0059] The cavity S is then filled with the injected molten thermoplastic resin 19. Here, the tread 34 has been subjected to a primer treatment with a chlorine compound at the portion that comes into contact with the molten thermoplastic resin 19, so that after the resin solidifies, the tread 34 and the thermoplastic resin 19 are directly and firmly bonded (adhered) together. Note that the term "directly bonded (adhered)" used here means that the rubber member and the thermoplastic resin are in direct contact with each other and are bonded together without any bonding material such as an adhesive being interposed between them.

[0060] In addition, since the rubber chafer 26 is treated with a primer of a chlorine compound at the portion that comes into contact with the molten thermoplastic resin 19, the rubber chafer 26 and the thermoplastic resin 19 are directly and firmly bonded (adhered) together after the resin solidifies.

[0061] Then, when the thermoplastic resin 19 solidifies, the molding of the tire 10 is completed. Thereafter, the first mold 42A and the second mold 42B are each moved in the mold opening direction, and the tire 10 is removed from the inner mold 44, thereby completing the production of the tire 10.

[0062] Next, the effects of this embodiment will be described. In the tire 10 of this embodiment, the belt layer 28 is included in the crown portion 16 of the tire frame member 18, and at least a portion of the inner circumferential surface of the belt layer 28 (in this embodiment, the entire inner circumferential surface of the belt layer 28) forms the inner circumferential surface of the crown portion 16. The tire 10 is a tire in which, when molding the resin tire frame member 18, the crown portion 16 can be formed in a state in which the belt layer 28 is arranged so that at least a portion of the inner circumferential surface of the belt layer 28 forms the inner circumferential surface of the crown portion 16. Therefore, because the belt layer 28 is arranged in the crown portion 16 when the tire frame member 18 is molded, the tire 10 has improved productivity compared to tires in which the belt layer is arranged on the tire radially outer side of the crown portion after the tire frame member is formed.

[0063] In the tire 10 of this embodiment, the belt layer 28 is formed by spirally winding a coated cord in the tire circumferential direction, the coated cord being formed by resin-coating one or more reinforcing cords 30. By including such a belt layer 28 in the crown portion 16, the rigidity of the crown portion 16 is improved, and tire performance is improved.

[0064] A tire having a resin tire frame member can be used as a retread tire (also called a retread tire) by removing the tread and replacing it with a new tread. However, if the tread is attached to the belt layer, there is a concern that the belt layer may be damaged when the tread is removed. In contrast, in the tire 10 of this embodiment, the crown portion 16 includes the belt layer 28 and the resin layer 29, so that damage to the belt layer 28 when the tread 34 is removed can be suppressed.

[0065] In the tire 10 of this embodiment, the resin layer 29 and the tread 34 are joined together, i.e., the outermost layer of the crown portion 16 is formed of the resin layer 29. Therefore, in the tire 10, when the tread 34 is peeled off while cutting the resin layer 29 along the tire circumferential direction, the amount of parts required to repair the tire frame member 18 after the tread 34 is peeled off can be reduced, compared to a configuration in which a resin layer forms an intermediate layer of the crown portion 16.

[0066] In the tire 10 of this embodiment, the belt layer 28 and the resin layer 29 are welded together, so that the bonding strength between the belt layer 28 and the resin layer 29 is high, and the rigidity of the crown portion 16 is improved.

[0067] In the tire 10 of the present embodiment, the resin constituting the belt layer 28 and the resin constituting the resin layer 29 are the same type of resin, so that the bonding strength between the belt layer 28 and the resin layer 29 is increased.

[0068] In the tire 10 of this embodiment, the resin layer 29 is made of only resin, so that even if the resin layer 29 is damaged when the tread 34 is peeled off, it is easier to repair the resin layer 29 compared to, for example, a configuration in which the resin layer 29 includes a reinforcing member other than resin.

[0069] Furthermore, in the tire 10 of this embodiment, the tire frame member 18 is formed only from the thermoplastic resin 19 in a region from the end 28A of the belt layer 28 in the tire width direction to the side portion 14. Therefore, the product of the thickness T of the resin (thermoplastic resin 19) of the tire frame member 18 in this region and the elastic modulus of the resin (thermoplastic resin 19) is set to 200 MPa·mm or more and 600 MPa·mm or less. Setting the product of the resin thickness T and the elastic modulus in this region to 200 MPa·mm or more can suppress local deformation of the tire frame member 18 in this region when the tire 10 rolls. On the other hand, setting the product of the resin thickness T and the elastic modulus to 600 MPa·mm or less can suppress cracks from occurring in this region of the tire frame member 18. Even if a crack occurs in this region, its propagation can be suppressed. That is, in the tire 10, by setting the product of the resin thickness T and the elastic modulus to 200 MPa·mm or more and 600 MPa·mm or less, local deformation is suppressed within the above range of the tire frame member 18, thereby improving pressure resistance performance, compared to a tire in which, for example, only the elastic modulus of the resin is set, and further, crack generation and crack propagation are suppressed within the above range of the tire frame member 18, thereby improving reliability during rolling.

[0070] In the tire 10 of this embodiment, by setting the product of the resin thickness T and the elastic modulus to 250 MPa·mm or more and 450 MPa·mm or less, the pressure resistance performance and rolling reliability of the tire frame member 18 within the above range are further improved.

[0071] In the tire 10 of this embodiment, a portion of the tread 34 (the protrusions 35) is in contact with the outer peripheral surface of the belt layer 28, and therefore the interface between the tread 34 and the crown portion 16 is not linear along the tire width direction but has a stepped shape in the tire width direction. Specifically, the protrusions 35 extend from the inner peripheral surface of the tread 34 toward the belt layer 28, and therefore the interface between the tread 34 and the crown portion 16 is configured to include an interface along the inner peripheral surface of the tread 34 and an interface along the outer peripheral surfaces of the protrusions 35. Here, the interface along the inner peripheral surface of the tread 34 is along the tire width direction, but the interfaces along the outer peripheral surfaces of the multiple protrusions 35 are along a direction intersecting the tire width direction (a direction perpendicular in this embodiment), and therefore the interface between the tread 34 and the crown portion 16 has a stepped shape in the tire width direction. Thus, in the tire 10, compared to a tire in which the interface between the tread 34 and the crown portion 16 is linear along the tire width direction, the stepped shape of the interface suppresses peeling at the interface and the progression of the peeled portion even when a shear force in the tire width direction is applied to the interface between the tread 34 and the crown portion 16. Therefore, with the tire 10, it is possible to suppress peeling of the tread 34 from the crown portion 16 in the tire frame member 18.

[0072] In the tire 10 of this embodiment, a plurality of protrusions 35 extending toward the outer peripheral surface of the belt layer 28 is provided on the inner peripheral surface of the tread 34, and the plurality of protrusions 35 penetrate the resin layer 29. Therefore, in the tire 10, the interface between the tread 34 and the crown portion 16 has a shape with a plurality of steps in the tire width direction. This makes it possible to further suppress peeling of the tread 34 from the crown portion 16 of the tire frame member 18 in the tire 10.

[0073] In the tire 10 of this embodiment, multiple protrusions 35 are spaced apart in the tire circumferential and widthwise directions, so that even if shear forces in the tire width and circumferential directions are applied to the interface between the tread 34 and the crown portion 16, the stepped shape of the interface can prevent the tread 34 from peeling off from the crown portion 16.

[0074] In the tire 10 of this embodiment, the through holes 36 provided in the tread 34 are filled with the thermoplastic resin 19 that forms the resin layer 29. Therefore, compared to a tire in which the through holes 36 are not filled with resin, for example, it is possible to visually confirm that the resin is filled without any gaps in the part that will become the resin layer 29 during manufacturing.

[0075] In the tire 10 of this embodiment, a portion of the rubber chafer 26 is in contact with the bead core 20 embedded in the bead portion 12. That is, in the tire 10, the bead portion 12 can be formed with a portion of the rubber chafer 26 in contact with the bead core 20 when the resin tire frame member 18 is molded. Because the rubber chafer 26 is disposed in the bead portion 12 when the tire frame member 18 is molded, the tire 10 has a higher degree of freedom in the shape of the rubber chafer 26 and it is easier to ensure the positioning accuracy of the rubber chafer 26 compared to tires in which the rubber chafer 26 is attached to the bead portion 12 after the tire frame member 18 is formed. Therefore, the tire has improved air sealing performance when mounted on a standard rim.

[0076] In the tire 10 of this embodiment, the rubber chafer 26 has multiple contact portions 27 that come into contact with the bead core 20 spaced apart around the tire, making it possible to prevent the bead core 20 from shifting in position due to the injection pressure when molding the tire frame member 18.

[0077] In the tire 10 of this embodiment, the contact portion 27 supports the bead core 20 from the outside in the tire width direction, so there is no need to extend the rubber chafer 26 to a predetermined height inside the bead portion 12, and the amount of rubber that makes up the rubber chafer 26 can be reduced.

[0078] In the tire 10 of this embodiment, the thickness of the side portion 14 increases in a portion corresponding to the end 26B of the rubber chafer 26 on the outer side in the tire radial direction, thereby ensuring strength in the portion of the side portion 14 on the bead portion 23 side. Also, in the tire 10, as shown in Fig. 10, the end 26B of the rubber chafer 26 fits into the cavity S so that the thickness of the side portion 14 increases in a portion corresponding to the end 26B of the rubber chafer 26, thereby preventing the injected molten resin from entering between the rubber chafer 26 and the second die 42B.

[0079] Furthermore, in the tire 10 of this embodiment, the portions of the tread 34 and the rubber chafer 26 that come into contact with the thermoplastic resin 19 are primed, and therefore, compared to when the primer treatment is not applied, the tread 34 and the rubber chafer 26 can be directly and firmly bonded (adhered) to the thermoplastic resin 19 that forms the tire frame member 18. Note that, here, "directly bonded" means that the rubber member and the thermoplastic resin come into direct contact with each other and are bonded without any adhesive or the like interposed between them.

[0080] Furthermore, in the tire 10 of the present embodiment, the belt layer 28, the rubber chafer 26, and the bead core 20 are bonded to the thermoplastic resin 19 by bringing the molten thermoplastic resin 19 that forms the tire frame member 18 into contact with the belt layer 28, the rubber chafer 26, and the bead core 20. This improves productivity compared to the case where the belt layer 28, the rubber chafer 26, and the bead core 20 are bonded to the tire frame member 18 that has been molded in advance (hardened thermoplastic resin) using an adhesive.

[0081] 2 , in the tire 10 of this embodiment, the resin thickness dimension t1 between the tread 34 and the reinforcement cords 30 of the belt layer 28 is set to be thicker than the resin thickness dimension t2 between the inner circumferential surface of the crown portion 16 and the reinforcement cords 30, thereby increasing the distance from the tread 34 to the longitudinal ends of the reinforcement cords 30 of the belt layer 28. This makes it difficult for forces acting from the tread surface side of the tread 34 to act near the ends of the reinforcement cords 30, thereby making it possible to suppress peeling and damage to the resin (thermoplastic resin 19, thermoplastic resin 32) around the longitudinal ends of the reinforcement cords 30.

[0082] In the manufacturing method of the tire 10 of this embodiment, the belt layer 28 and the tread 34 are set in the cavity S so that a gap is formed between them. In this embodiment, the belt layer 28 and the tread 34 are set in the cavity S with a portion of the tread 34 in contact with the belt layer 28 so that a gap is formed between them. In addition, the bead cores 20 held by the holding portions 48 and the rubber chafers 26 are set with a portion of the bead cores 20 in contact with the bead cores 20 from the side opposite the holding portions 48. Next, a molten thermoplastic resin 19 is injected into the cavity S to form the tire frame member 18.

[0083] The crown portion 16 of the molded tire frame member 18 includes a belt layer 28 and a resin layer 29 formed of molten thermoplastic resin 19 filled in the gap between the belt layer 28 and a tread 34. The inner circumferential surface of the crown portion 16 is formed by at least a portion of the inner circumferential surface of the belt layer 28 (in this embodiment, the entire inner circumferential surface of the belt layer 28). The tread 34 is then disposed on the outer periphery of the crown portion 16 of the tire frame member 18. In this manner, in the manufacturing method of the tire 10, the crown portion 16 of the tire frame member 18 is formed from the molten thermoplastic resin 19 with the belt layer 28 set in the cavity S. That is, in the above manufacturing method, the belt layer 28 is disposed in the crown portion 16 when the tire frame member 18 is molded, and therefore productivity is improved compared to a manufacturing method in which the belt layer 28 is disposed on the tire radially outer side of the crown portion 16 after the tire frame member 18 is formed.

[0084] Furthermore, in the molded tire frame member 18, a portion of the tread 34 is in contact with the outer peripheral surface of the belt layer 28, so the interface between the tread 34 and the crown portion 16 is not linear along the tire width direction but has a stepped shape in the tire width direction. Therefore, in the tire 10 manufactured by the above manufacturing method, the stepped shape of the interface suppresses peeling at the interface and the progression of the peeled portion, compared to a tire in which the interface between the tread 34 and the crown portion 16 is linear along the tire width direction, even when a shear force in the tire width direction is applied to the interface between the tread 34 and the crown portion 16. Therefore, according to the manufacturing method of the tire 10, it is possible to manufacture a tire 10 that can suppress peeling of the tread 34 from the crown portion 16 in the tire frame member 18.

[0085] Furthermore, bead cores 20 are embedded in the bead portions 12 of the molded tire frame member 18, and rubber chafers 26 are disposed in contact with the bead cores 20. In this manner, in the manufacturing method of the tire 10, the bead portions 12 are formed with portions of the rubber chafers 26 in contact with the bead cores 20 when the resin tire frame member 18 is molded. Therefore, in the manufacturing method of the tire 10, the rubber chafers 26 are disposed in the bead portions 12 when the tire frame member 18 is molded. Therefore, compared to tire manufacturing methods in which the rubber chafers 26 are attached to the bead portions 12 after the tire frame member 18 is formed, the manufacturing method of the tire 10 has a higher degree of freedom in the shape of the rubber chafers 26 and makes it easier to ensure the positioning accuracy of the rubber chafers 26. Therefore, a tire manufactured by the above tire manufacturing method has improved air sealing performance when mounted on a standard rim.

[0086] In the manufacturing method of the tire 10 of this embodiment, the molten thermoplastic resin 19 is injected into the cavity S from both outer sides of the tread 34 in the tire width direction, making it easy to fill the cavity S with the molten thermoplastic resin 19 without any gaps.

[0087] In the manufacturing method of the tire 10 of this embodiment, the tread 34 and the belt layer 28 are set in the cavity S so that a portion of the tread 34 contacts the belt layer 28 and supports each other, thereby ensuring a gap between the tread 34 and the belt layer 28. This makes it possible to manufacture a high-quality tire in which the resin layer 29 has a predetermined thickness.

[0088] In the manufacturing method of the tire 10 of this embodiment, the through holes 36 are provided in the tread 34, so that gas generated when the molten thermoplastic resin 19 is injected into the cavity S can be discharged to the outside through the through holes 36. This makes it easy to fill the gap between the tread 34 and the belt layer 28 with the molten thermoplastic resin 19.

[0089] In the manufacturing method of the tire 10 of this embodiment, the bead core 20 is held by being sandwiched between the holding portion 48 and a part of the rubber chafer 26 in the mold clamping direction of the second mold 42B, so that the position of the bead core 20 can be prevented from shifting due to the injection pressure of the molten thermoplastic resin 19.

[0090] [Other Embodiments] Although one example of an embodiment of the present disclosure has been described above, the embodiment of the present disclosure is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure.

[0091] In the above-described embodiment, the crown portion 16 has a two-layer structure of the belt layer 28 and the resin layer 29, but the present disclosure is not limited to this configuration. For example, the crown portion 16 may be formed of only the belt layer. Specifically, in FIG. 2 , the resin layer 29 may be omitted by forming a belt layer in which the resin thickness dimension t1 above the reinforcement cord 30 of the coated cord is greater than the resin thickness dimension t2. In this case, it is preferable to apply a primer treatment to the flat inner peripheral surface of the tread 34 and then join the belt layer 28, the outer peripheral surface of which has been melted, to the inner peripheral surface of the tread 34.

[0092] In the above-described embodiment, the inner circumferential surface of the belt layer 28 forms the inner circumferential surface of the crown portion 16. However, the present disclosure is not limited to this configuration. Another layer may be formed radially inward of the belt layer 28, and the inner circumferential surface of the other layer may form the inner circumferential surface of the crown portion 16. For example, as in a tire 110 shown in FIGS. 13 and 14 , the crown portion 16 may have a three-layer structure of a resin film 112, a belt layer 28, and a resin layer 29, and the inner circumferential surface of the resin film 112 may form the inner circumferential surface of the crown portion 16. Specifically, by arranging the resin film 112 wider than the belt layer 28 on the radially inner side of the belt layer 28 in the crown portion 16, the inner circumferential surface of the resin film 112 forms the inner circumferential surface of the crown portion 16. Furthermore, both end portions 112A of the resin film 112 in the tire width direction are located outward in the tire width direction from both end portions 28A of the belt layer 28 in the tire width direction. Furthermore, the belt layer 28 and the resin film 112 may be welded to each other. By disposing such a resin film 112 on the inner side in the tire radial direction of the belt layer 28, it is possible to, for example, reduce the difference in rigidity near the end portion 28A of the belt layer 28, and to suppress the occurrence of cracks, etc. The resin film referred to here refers to one with a thickness of less than 1 mm.

[0093] In addition to the above-described embodiments, the following supplementary notes are also disclosed.

[0094] (Note 1) A tire comprising: a tire frame member made of resin, the tire frame member having bead portions, side portions continuous with the bead portions on the outer side in the tire radial direction, and a crown portion continuous with the side portions on the inner side in the tire width direction; and a tread disposed on the outer side in the tire radial direction of the crown portion, wherein the crown portion includes a belt layer in which one or more reinforcing cords are resin-coated, and a resin layer disposed on the outer side in the tire radial direction of the belt layer, and a part of the tread is in contact with an outer peripheral surface of the belt layer.

[0095] In the tire of Supplementary Note 1, because a portion of the tread is in contact with the outer peripheral surface of the belt layer, the interface between the tread and the outer peripheral surface of the crown portion is not linear along the tire width direction but has a stepped shape in the tire width direction. Therefore, in the tire, compared to a tire in which the interface between the tread and the outer peripheral surface of the crown portion is linear along the tire width direction, even if a shear force in the tire width direction is applied to the interface between the tread and the outer peripheral surface of the crown portion, the stepped shape of the interface suppresses peeling at the interface and the progression of the peeled portion. Therefore, with the tire, it is possible to suppress peeling of the tread from the crown portion of the tire frame member.

[0096] (Supplementary Note 2) The tire according to Supplementary Note 1, wherein an inner circumferential surface of the tread is provided with a plurality of protrusions protruding toward an outer circumferential surface of the belt layer, and the plurality of protrusions penetrate the resin layer.

[0097] In the tire of Supplementary Note 2, a plurality of protrusions are provided on the inner peripheral surface of the tread, protruding toward the outer peripheral surface of the belt layer, and the plurality of protrusions penetrate the resin layer, so that the interface between the tread and the outer peripheral surface of the crown portion has a shape with a plurality of steps in the tire width direction. This makes it possible to further suppress peeling of the tread from the crown portion of the tire frame member in the tire.

[0098] (Supplementary Note 3) The tire according to Supplementary Note 2, wherein the plurality of protrusions are provided at intervals in the tire circumferential direction and the tire width direction.

[0099] In the tire of Appendix 3, the plurality of protrusions are provided at intervals in the tire circumferential direction and the tire width direction, so that even if shear forces in the tire width direction and the tire circumferential direction are applied to the interface between the tread and the crown portion, the stepped shape of the interface can suppress peeling of the tread from the crown portion.

[0100] (Supplementary Note 4) The tire according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the tread is provided with a through hole penetrating in a tire radial direction, and the through hole is filled with a resin that forms the resin layer.

[0101] In the tire of Appendix 4, the through holes provided in the tread are filled with resin that forms the resin layer. Therefore, compared to a tire in which the through holes are not filled with resin, for example, it can be visually confirmed that the resin is filled without any gaps in the part that will become the resin layer during manufacturing.

[0102] (Appendix 5) The tire according to any one of Appendices 1 to 4, wherein the belt layer is formed by winding a coated cord, which is obtained by coating one or more of the reinforcing cords with a resin, spirally in the tire circumferential direction.

[0103] In the tire of Appendix 5, a belt layer is formed by winding a coated cord, which is one or more reinforcing cords coated with a resin, spirally in the tire circumferential direction. By including such a belt layer in the crown portion, the rigidity of the crown portion is improved, and tire performance is improved.

[0104] (Appendix 6) The tire according to any one of Appendices 1 to 5, wherein the resin layer and the tread are bonded together.

[0105] In the tire of Supplementary Note 6, the resin layer and the tread are joined together, i.e., the outermost layer of the crown portion is formed of a resin layer. Therefore, in the tire, when the tread is peeled off while cutting the resin layer along the tire circumferential direction, the amount of parts required to repair the tire frame member after the tread is peeled off can be reduced compared to a configuration in which the resin layer forms an intermediate layer of the crown portion.

[0106] (Appendix 7) The tire according to any one of Appendices 1 to 6, wherein the belt layer and the resin layer are welded together.

[0107] In the tire of Supplementary Note 7, the belt layer and the resin layer are welded together, so that the joining strength between the belt layer and the resin layer is high, and the rigidity of the crown portion is improved.

[0108] (Appendix 8) The tire according to any one of Appendices 1 to 7, wherein a resin constituting the belt layer and a resin constituting the resin layer are the same resin.

[0109] In the tire of Appendix 8, the resin constituting the belt layer and the resin constituting the resin layer are the same resin, so that the bonding strength between the belt layer and the resin layer is higher.

[0110] (Appendix 9) The tire according to any one of Appendices 1 to 8, wherein the resin layer is formed of only a resin.

[0111] In the tire of Appendix 9, since the resin layer is made of only resin, even if the resin layer is damaged when the tread is peeled off, the resin layer can be easily repaired, compared to a configuration in which the resin layer includes a reinforcing member other than resin, for example.

[0112] (Appendix 10) A method for manufacturing a tire, comprising: a step of setting a belt having one or more reinforcing cords resin-coated and a vulcanized or semi-vulcanized tread in a cavity formed by a tire molding mold, with a part of the tread in contact with the belt so that a gap is formed between them; and a step of injecting molten resin into the cavity to mold a tire frame member having bead portions, side portions continuous with the bead portions on the outer side in the tire radial direction, and a crown portion continuous with the side portions on the inner side in the tire width direction.

[0113] In the tire manufacturing method of Appendix 10, first, a belt having one or more resin-coated reinforcing cords and a vulcanized or semi-vulcanized tread are set in a cavity formed by a tire molding die, with a portion of the tread in contact with the belt so as to form a gap between them. Next, molten resin is injected into the cavity to mold a tire frame member having a bead portion, a side portion, and a crown portion. In the molded tire frame member, a portion of the tread is in contact with the outer peripheral surface of the belt layer, so that the interface between the tread and the outer peripheral surface of the crown portion is not linear along the tire width direction but has a stepped shape in the tire width direction. Therefore, compared to a tire in which the interface between the tread and the outer peripheral surface of the crown portion is linear along the tire width direction, a tire manufactured by the above manufacturing method has a stepped shape at the interface that suppresses peeling at the interface and the progression of the peeled portion even when a shear force in the tire width direction is applied to the interface between the tread and the outer peripheral surface of the crown portion. Therefore, the above tire manufacturing method makes it possible to manufacture a tire that can suppress peeling of the tread from the crown portion of the tire frame member.

[0114] (Supplementary Note 11) The tire manufacturing method according to Supplementary Note 10, wherein the tread has through holes formed therein in a thickness direction, and the molten resin is injected into the through holes by injection pressure.

[0115] In the tire manufacturing method of Appendix 11, since the through holes are provided in the tread in the thickness direction, gas generated when the molten resin is injected into the cavity can be discharged to the outside through the through holes, which makes it easy to fill the gap between the tread and the belt layer with the molten resin.

[0116] (Supplementary Note 12) The tire manufacturing method according to Supplementary Note 10 or Supplementary Note 11, wherein the molten resin is injected into the cavity from both outer sides of the tread in the tire width direction.

[0117] In the tire manufacturing method of Supplementary Note 12, the molten resin is injected into the cavity from both outer sides of the tread in the tire width direction, so that the cavity can be easily filled with the molten resin without any gaps.

[0118] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0119] In addition, the disclosure of Japanese Patent Application No. 2024-065800, filed on April 15, 2024, is incorporated herein by reference in its entirety.

Claims

1. A tire comprising: a resin tire frame member having bead portions, side portions connected to the radially outer side of the bead portions, and a crown portion connected to the radially inner side of the side portions; and a tread arranged radially outward of the crown portion, wherein the crown portion includes a belt layer having one or more resin-coated reinforcing cords, and a resin layer arranged radially outward of the belt layer, and wherein a portion of the tread is in contact with the outer peripheral surface of the belt layer.

2. A tire as set forth in claim 1, wherein the inner peripheral surface of the tread is provided with a plurality of protrusions that protrude toward the outer peripheral surface of the belt layer, and the plurality of protrusions penetrate the resin layer.

3. The tire according to claim 2, wherein the plurality of protrusions are provided at intervals in the tire circumferential direction and the tire width direction.

4. A tire according to any one of claims 1 to 3, wherein the tread is provided with through holes that penetrate in the tire radial direction, and the through holes are filled with the resin that forms the resin layer.

5. A tire according to any one of claims 1 to 4, wherein the belt layer is formed by winding a coated cord, which is one or more of the reinforcing cords coated with resin, spirally in the tire circumferential direction.

6. A tire according to any one of claims 1 to 5, wherein the resin layer and the tread are bonded together.

7. The tire according to any one of claims 1 to 6, wherein the belt layer and the resin layer are welded together.

8. A tire according to any one of claims 1 to 7, wherein the resin constituting the belt layer and the resin constituting the resin layer are the same resin.

9. A tire according to any one of claims 1 to 8, wherein the resin layer is composed of only resin.

10. A method for manufacturing a tire, comprising: a step of setting a belt having one or more resin-coated reinforcing cords and a vulcanized or semi-vulcanized tread in a cavity formed by a tire molding mold, with a portion of the tread in contact with the belt so that a gap is formed between them; and a step of injecting molten resin into the cavity to form a tire frame member having bead portions, side portions connected to the outer side of the bead portions in the tire radial direction, and a crown portion connected to the inner side of the side portions in the tire width direction.

11. A method for manufacturing a tire as set forth in claim 10, wherein the tread has through holes formed in the thickness direction, and the molten resin is injected into the through holes by injection pressure.

12. The method for manufacturing a tire according to claim 10 or 11, wherein the molten resin is injected into the cavity from both outer sides of the tread in the tire width direction.

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