Method for manufacturing resin structures

Abstract

The present invention provides a method for manufacturing a resin structure that can easily accommodate changes to the resin structure. [Solution] A method for manufacturing a resin structure is a method for manufacturing a resin structure that includes a resin substrate having a plurality of shaped parts, and comprises: a mother structure creation step (step S1) of creating a mother structure by additive manufacturing; a mold creation step (step S2) of creating a mold by making a mold based on the mother structure; a mold resin injection step (step S5) of injecting a molding resin into the mold; a mold resin curing step (step S6) of curing the molding resin injected into the mold; and a cast product removal step (step S7) of removing a cast product from the mold.

Description

Technical Field

[0001] The present invention relates to a method for producing a resin structure.

Background Art

[0002] As a conventional method for producing a resin structure, for example, a method for producing a non-pneumatic tire using mold molding in which molding is performed by curing a molten resin supplied into a cavity of a molding die is known (see, for example, Patent Document 1).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] However, the production method using mold molding requires a lot of time and cost from the structural design of the mold to the completion of the mold. Therefore, it is not easy for the production method using mold molding to cope with a change in the resin structure when the resin structure is modified.

[0005] An object of the present invention is to provide a method for producing a resin structure that can easily cope with a change in the resin structure.

Means for Solving the Problem

[0006] (1) The present invention relates to a method for manufacturing a resin structure, which is a method for manufacturing a resin structure comprising a resin substrate having a plurality of shaped parts, and includes: a mother structure creation step of creating a mother structure by additive manufacturing; a mold creation step of creating a mold by making a mold based on the mother structure; a mold resin injection step of injecting a molding resin into the mold; a mold resin curing step of curing the molding resin injected into the mold; and a cast product removal step of removing a cast product from the mold.

[0007] (2) In the method for manufacturing the resin structure described in (1) above, the resin structure is a non-pneumatic tire comprising a tire body having an inner cylindrical shape portion that is fitted onto a wheel fixed to an axle, an outer cylindrical shape portion that surrounds the inner cylindrical shape portion, and a connecting piece shape portion that radially connects the inner cylindrical shape portion and the outer cylindrical shape portion, and a tread member fitted onto the outer cylindrical shape portion, wherein the resin substrate may be the tire body.

[0008] (3) In the mother structure creation step of the resin structure manufacturing method described in (1) or (2) above, the additive manufacturing method may be one of the following: fused deposition modeling, sheet lamination, or stereolithography.

[0009] (4) In the mold making step of any one of the above methods for manufacturing a resin structure (1) to (3), the mold may be made by molding using a silicone material.

[0010] (5) In the molding resin injection step of any one of the above (1) to (4) methods for manufacturing a resin structure, the molding resin injected into the mold is a thermosetting resin, and in the molding resin curing step, the molding resin can be cured by heating the molding resin.

[0011] (6) In the molding resin injection step of any one of the above (1) to (4) methods for manufacturing a resin structure, the molding resin injected into the mold is a thermoplastic resin, and in the molding resin curing step, the molding resin can be cured by lowering the temperature of the molding resin.

[0012] (7) In the resin injection step of the method for manufacturing the resin structure described in (6) above, the temperature of the mold when injecting the resin may be 5°C or higher and 60°C or lower.

[0013] (8) In the mother structure creation step of the resin structure manufacturing method described in (2) above, the mother structure is a prototype used for molding the resin substrate, and in the mold creation step, the mold may be created by performing molding with the tread member attached to the mother structure.

[0014] (9) In the resin injection step of the method for manufacturing the resin structure described in (8) above, the tread member may be placed in the mold before the resin is injected.

[0015] (10) In the method for manufacturing the resin structure described in (9) above, the tread member placed in the mold may be subjected to chlorination treatment on its radially inner surface.

[0016] (11) In the method for manufacturing a resin structure described in (9) or (10) above, the tread member placed in the mold may have an adhesive applied to its radially inner surface. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a method for manufacturing a resin structure that can be easily adapted to changes in the resin structure. [Brief explanation of the drawing]

[0018] [Figure 1] It is a side view schematically showing, together with a wheel, a non-pneumatic tire that can be manufactured by the method for manufacturing a resin structure according to an embodiment of the present invention. [Figure 2] It is a side view showing only the non-pneumatic tire of FIG. 1. [Figure 3] It is a flowchart schematically showing an example of an implementation procedure of the method for manufacturing a resin structure according to an embodiment of the present invention, which is a procedure for manufacturing the non-pneumatic tire of FIG. 2. [Figure 4] It is a perspective view schematically and perspectively showing a resin base constituting the non-pneumatic tire of FIG. 2. [Figure 5A] It is an explanatory view for explaining a mold forming step according to the method for manufacturing a resin structure according to an embodiment of the present invention, which is for explaining the step of supplying a molding material into the inside of a mold frame in order to perform molding of a master product. [Figure 5B] It is another explanatory view for explaining the mold forming step, which is for explaining the step of forming a molding die as a split mold by splitting a mold block taken out from the mold frame and taking out the master product after the step of FIG. 5A. [Figure 5C] It is still another explanatory view for explaining the mold forming step, in which the completed molding die after the step of FIG. 5B is shown in a state where the split molds are combined. [Figure 6] It is an explanatory view for explaining a molding resin injection step according to the method for manufacturing a resin structure according to the present embodiment, which is for explaining the step of arranging a tread member as an insert product on one of the split molds of the molding die before the step of injecting the molding resin into the molding die. [Figure 7] It is another explanatory view for explaining the molding resin injection step according to the method for manufacturing a resin structure according to the present embodiment, which is for explaining the step of injecting the molding resin into the molding die after the step of FIG. 6. [Figure 8]It is an explanatory diagram for explaining the molded resin curing step according to the method for manufacturing a resin structure of the present embodiment. [Figure 9] It is an explanatory diagram for explaining the cast product removal step according to the method for manufacturing a resin structure of the present embodiment. MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, a method for manufacturing a resin structure which is an embodiment of the present invention will be described with reference to the drawings.

[0020] Fig. 1 schematically shows a non-pneumatic tire 1, which can be manufactured by the method for manufacturing a resin structure according to an embodiment of the present invention, together with a wheel 4 from a side view.

[0021] As shown in Fig. 1, the non-pneumatic tire 1 includes: a resin base body 2 that is mounted on the outer side in the tire radial direction B of the wheel 4 attached to an axle 5; and a cylindrical tread member 3 that is mounted on the outer side in the tire radial direction B of the resin base body 2. The non-pneumatic tire 1 in Fig. 1 is a so-called bottom-load type non-pneumatic tire that supports a load mainly by the resin base body 2 below the axle 5.

[0022] The wheel 4 includes: a cylindrical mounting cylinder portion 41 to which an axial end of the axle 5 is mounted; a cylindrical outer peripheral cylinder portion 42 surrounding the mounting cylinder portion 41 from the outer side in the tire radial direction B; and a plurality of connecting ribs 43 connecting the mounting cylinder portion 41 and the outer peripheral cylinder portion 42. The outer peripheral cylinder portion 42 defines a circumferential groove extending over the entire circumference in the tire circumferential direction C on the outer peripheral surface in the tire radial direction B. Provision of the wheel 4 allows the resin base body 2 to be easily attached to the axle 5.

[0023] In this embodiment, the resin base 2 is the tire body. In this embodiment, the resin base 2 comprises a plurality of shaped parts. The resin base 2 comprises an inner cylindrical shaped part 21 that is fitted onto a wheel fixed to an axle, an outer cylindrical shaped part 22 that surrounds the inner cylindrical shaped part 21 from the radially outer side, and a connecting piece shaped part 23 that connects the inner cylindrical shaped part 21 and the outer cylindrical shaped part 22 in the radial direction. In this disclosure, the connecting piece shaped part 23 is an elastically deformable connecting piece shaped part.

[0024] Here, the mounting cylinder portion 41 and outer cylinder portion 42 of the wheel 4, the inner cylinder-shaped portion 21 and outer cylinder-shaped portion 22 of the resin base 2, and the tread member 3 are arranged so that their respective central axes are coaxial (share a common central axis O). Furthermore, in this embodiment, the mounting cylinder portion 41 and outer cylinder portion 42 of the wheel 4, the inner cylinder-shaped portion 21 and outer cylinder-shaped portion 22 of the resin base 2, and the tread member 3 are arranged so that their respective central portions in the tire width direction A coincide with each other.

[0025] The mounting cylinder portion 41, the outer circumferential cylinder portion 42, and the connecting ribs 43 of the wheel 4 are each integrally formed from a metal material such as an aluminum alloy or a resin material such as polypropylene. In this embodiment, the multiple connecting ribs 43 are arranged so as to be point-symmetric with respect to the central axis O in a side view, as shown in Figure 1.

[0026] Furthermore, in this embodiment, the outer cylindrical portion 22 of the resin substrate 2 has a larger size in the tire width direction A, i.e., a larger width, than the inner cylindrical portion 21.

[0027] The connecting piece-shaped portion 23 is composed of a plurality of connecting plates 23a arranged at intervals in the tire circumferential direction C. The plurality of connecting plates 23a are arranged between the inner cylindrical-shaped portion 21 and the outer cylindrical-shaped portion 22 of the resin base 2 so as to be point-symmetric with respect to the central axis O. In this embodiment, each connecting plate 23a has the same size and shape. Furthermore, in this embodiment, the width A in the tire width direction of each connecting plate 23a is smaller than the width A in the tire width direction of the outer cylindrical-shaped portion 22.

[0028] In this embodiment, adjacent connecting plates 23a in the tire circumferential direction C are arranged with a gap between them in the tire circumferential direction C, and are not in contact with each other.

[0029] In this embodiment, of each connecting plate 23a, the outer end 23a1 on the outside in the tire radial direction B, which is connected to the outer cylindrical portion 22, is located on one side in the tire circumferential direction C than the inner end 23a2 on the inside in the tire radial direction B, which is connected to the inner cylindrical portion 21. In other words, the outer end 23a1 and the inner end 23a2 of the connecting plate 23a are positioned at different locations in the tire circumferential direction C. By inclining the connecting plate 23a with respect to the tire radial direction B in this way, the connecting plate 23a can be used as a leaf spring that is easily elastically deformable in the tire radial direction B.

[0030] In this embodiment, the inner cylindrical portion 21, the outer cylindrical portion 22, and the connecting piece portion 23 of the resin substrate 2 are made of resin. This makes it possible to reduce the weight of the inner cylindrical portion 21, the outer cylindrical portion 22, and the connecting piece portion 23, i.e., the resin substrate 2. In this embodiment, the inner cylindrical portion 21, the outer cylindrical portion 22, and the connecting piece portion 23 of the resin substrate 2 are integrally formed from resin material by insert molding using the tread member 3 as the insert material. Furthermore, the resin material may be, for example, a single type of resin material, a mixture containing two or more types of resin materials, or a mixture containing one or more types of resin materials and one or more types of elastomers. In addition, the resin material may contain additives such as, for example, an antioxidant, a plasticizer, a filler, or a pigment. The resin material is preferably a thermoplastic resin.

[0031] However, examples of the resin material include thermoplastic resins and thermosetting resins. Specifically, the resin material can be thermoplastic resins such as polyester and nylon, thermosetting resins such as vinyl ester resins and unsaturated polyester resins, and other synthetic resins. The resin material may further contain reinforcing fibers such as glass, carbon, graphite, aramid, polyethylene, and ceramic.

[0032] In this embodiment, the resin substrate 2 is composed of the inner cylindrical portion 21, the outer cylindrical portion 22, and the connecting piece portion 23 described above, but it may also be a resin substrate having other shaped portions.

[0033] In this embodiment, the resin base 2 is restricted from relative movement in the tire width direction A relative to the wheel 4 by housing its inner cylindrical portion 21 within a circumferential groove defined on the outer circumferential surface of the outer cylindrical portion 42 of the wheel 4 in the tire radial direction B. Furthermore, the resin base 2 is restricted from relative movement in the tire circumferential direction C relative to the wheel 4 by bolting its inner cylindrical portion 21 to the outer cylindrical portion 42 of the wheel 4 with bolts 6. In this way, the resin base 2 according to this embodiment is fixed to the wheel 4. However, the fixing of the wheel 4 and the resin base 2 is not limited to the fixing means described above. Relative movement of the wheel 4 and the resin base 2 in the tire circumferential direction C may also be restricted, for example, by fitting a convex portion provided on either the outer circumferential surface of the outer cylindrical portion 42 of the wheel 4 or the inner circumferential surface of the inner cylindrical portion 21 of the resin base 2 with a concave portion provided on the other.

[0034] The tread member 3 is formed in a cylindrical shape and covers the entire outer circumferential surface of the outer cylindrical portion 22 of the resin substrate 2. The outer circumferential surface of the tread member 3 constitutes the tread surface 3a of the non-pneumatic tire 1. In this embodiment, the tread member 3 is formed of, for example, vulcanized rubber obtained by vulcanizing a rubber composition including natural rubber, or a thermoplastic material. Examples of thermoplastic materials include thermoplastic elastomers and thermoplastic resins. Examples of thermoplastic elastomers include amide-based thermoplastic elastomers (TPA), ester-based thermoplastic elastomers (TPC), olefin-based thermoplastic elastomers (TPO), styrene-based thermoplastic elastomers (TPS), urethane-based thermoplastic elastomers (TPU), thermoplastic rubber crosslinked material (TPV), and other thermoplastic elastomers (TPZ) as specified in JIS K 6418. Examples of thermoplastic resins include urethane resin, olefin resin, vinyl chloride resin, and polyamide resin.

[0035] Furthermore, from the viewpoint of wear resistance, it is preferable to form the tread member 3 from vulcanized rubber.

[0036] Next, an embodiment of the present invention, a procedure for manufacturing a resin structure, will be described using the procedure for manufacturing a non-pneumatic tire 1 as an example.

[0037] Figure 2 shows only the non-pneumatic tire 1 shown in Figure 1 from a side view. Figure 3 is a flowchart illustrating an example of a procedure for manufacturing a resin structure, which is one embodiment of the present invention, and schematically shows the procedure for manufacturing the non-pneumatic tire 1 shown in Figure 2.

[0038] The present invention relates to a method for manufacturing a resin structure, which is a method for manufacturing a resin structure (1) that includes at least one resin substrate (2) having a plurality of shaped parts (21-23). ​​The method for manufacturing a resin structure (1) includes a mother structure creation step of creating a mother structure (F0) by additive manufacturing, a mold creation step of creating a mold (10) by making a mold based on the mother structure (F0), a mold resin injection step of injecting a molding resin (MR) into the mold (10), a mold resin curing step of curing the molding resin (MR) injected into the mold (10), and a cast product removal step of removing the cast product (1) from the mold (10).

[0039] As shown in Figure 2, in this embodiment, the resin structure (1) is a non-pneumatic tire 1 comprising a resin base 2 having an inner cylindrical shape portion 21 that is fitted over a wheel 4 fixed to an axle 5, an outer cylindrical shape portion 22 that surrounds the inner cylindrical shape portion 21, and a connecting piece shape portion 23 that radially connects the inner cylindrical shape portion 21 and the outer cylindrical shape portion 22, and a tread member 3 fitted over the outer cylindrical shape portion 22. In the non-pneumatic tire 1 according to this embodiment, the resin base 2 is the tire body.

[0040] In this embodiment, the method for manufacturing a resin structure begins with a mother structure creation step. As shown in step S1 of Figure 3, in the mother structure creation step according to this embodiment, a mother structure F0 used for manufacturing the resin structure (1) is created by using an additive manufacturing method. In this embodiment, the mother structure F0 is a prototype used for molding the resin substrate 2. The mother structure F0 is created using a so-called 3D printer. In this embodiment, the external shape of the resin substrate 2 is taken into a computing device such as a computer as image data using image processing technology such as a scanner. As a result, the mother structure F0 is created using a 3D printer based on the image data of the resin substrate 2. Figure 4 shows the mother structure F0 created by the additive manufacturing method.

[0041] In this embodiment, the additive manufacturing method used in the mother structure creation process can be selected from, for example, fused deposition modeling (FDM), sheet lamination, or stereolithography. When using FDM, for example, a three-dimensional shape (resin substrate 2) can be created by laminating resin melted at high temperatures using a heating means such as a heater or laser. When using sheet lamination, a three-dimensional shape (resin substrate 2) can be created by laminating thin sheets of resin material. When using stereolithography, a three-dimensional shape (resin substrate 2) can be created by laminating photocurable resin that hardens when irradiated with light (including invisible light such as ultraviolet rays).

[0042] Next, in this embodiment, the method for manufacturing a resin structure involves a master product creation process following a mother structure creation process. As shown in step S2 of Figure 3, in the master product creation process according to this embodiment, a master product F1 is formed by covering the mother structure F0, which is created by additive manufacturing, with a tread member 3. The master product F1 is the original mold (the base mold for the replicated resin structure (1)) of the resin structure (non-pneumatic tire 1) molded (replicated) using the casting method described later. In this embodiment, the mother structure F0 is the original mold used for molding the resin substrate 2. However, if the resin structure (1) consists only of the resin substrate 2, the mother structure creation process also serves as the master product creation process, and step S2 of Figure 3 can be omitted.

[0043] Next, in this embodiment, the method for manufacturing a resin structure involves a mold creation process following a master product creation process. In the mold creation process, a mold 10 is created by taking a mold based on the mother structure F0. In the mold creation process according to this embodiment, as shown in step S3 of Figure 3, the mold 10 is created by taking a mold of the master product (a master product of a non-pneumatic tire) F1 created in step S2.

[0044] In the mold making process according to this embodiment, the mold 10 is created by molding using a silicone material MS. The molding is performed, for example, by pouring liquid silicone material MS into a mold 50 containing a master product F1, as shown in Figure 5A. When the silicone S poured into the mold 50 hardens, a mold block (silicone block) is formed inside the mold 50.

[0045] Next, in the mold creation process according to this embodiment, the mold block is removed from the mold frame 50, and then the master product F1 is removed from the mold block to create the mold 10. Figure 5B shows the state in which, after the process in Figure 5A, the mold block removed from the mold frame 50 is divided and the master product F1 is removed, thereby forming the mold 10 as a divided mold.

[0046] Furthermore, Figure 5C shows the mold 10 completed after the process in Figure 5B, with the split molds (11, 12) joined together. In Figure 5C, the mold 10 is exemplary in that it is composed of two split molds, split mold 11 and split mold 12. In this example, as shown in Figure 5C, a cavity 13 that forms the outer shape of the master product F1 is formed on the mating surface of split mold 11 and split mold 12. In this example, a cylindrical recess 14 is formed in one of the two split molds (11, 12), split mold 11, and a gate 15 leading to the cavity 13 is formed in the other split mold 12. In this example, the molding resin MR is supplied to the cavity 13 through the gate 15.

[0047] Next, in this embodiment, the method for manufacturing a resin structure involves an insert placement step after the mold creation step in step S3. In the insert placement step, the insert is placed inside the mold 10. As shown in step S4 of Figure 3, in the insert placement step according to this embodiment, the tread member 3 is placed inside the mold 10 before the molding resin MR is injected into the mold 10. Figure 6 shows that the tread member 3, as an insert, is placed in the recess 14 of the split mold 11 of the mold 10 before the step of injecting the molding resin MR into the mold 10. However, if the resin structure (1) is composed only of a resin substrate 2, step S4 (insert placement step) in Figure 3 can be omitted.

[0048] Furthermore, in the insert placement process (step S4), the tread member 3 placed in the mold 10 is subjected to chlorination treatment. In this case, for example, the aging deterioration of the non-pneumatic tire 1 as a cast product, as described later, is suppressed, thereby improving the durability of the non-pneumatic tire 1.

[0049] Furthermore, in the insert placement process (step S4), it is preferable that adhesive is applied to the radially inner surface of the tread member 3 placed in the mold 10. In this case, the bonding strength between the resin substrate 2 and the tread member 3 of the non-pneumatic tire 1 as a cast product is improved, thereby improving the durability of the non-pneumatic tire 1.

[0050] Next, in this embodiment, the method for manufacturing a resin structure involves a molding resin injection process after the insert placement process in step S4. As shown in step S5 of Figure 3, in the molding resin injection process, the molding resin MR is injected into the mold 10. Figure 7 shows the state after step S4 of Figure 3, where the molding resin MR is injected through the gate 15 into the cavity 13 formed inside the mold 10, into which the divided molds 11 and 12 are clamped.

[0051] Next, in this embodiment, the method for manufacturing a resin structure involves a molding resin curing step after the molding resin injection step in step S5. As shown in step S6 of Figure 3, the molding resin curing step cures the molding resin MR formed inside the mold 10. As a result, a resin structure (1) as a cast product is formed inside the mold 10. Figure 8 shows the state in which the resin structure (1) formed by the molding resin MR is formed inside the mold 10.

[0052] According to this embodiment, in the molding resin injection process (step S5), the molding resin MR injected into the mold 10 can be a thermosetting resin. In this case, in the molding resin curing process (step S6), the molding resin MR is cured by heating it. In this case, by using an existing thermosetting resin, the resin substrate 2 can be molded at low cost.

[0053] Furthermore, according to this embodiment, the molding resin MR injected into the mold 10 in the molding resin injection step (step S5) can be a thermoplastic resin. In this case, in the molding resin curing step (step S6), the molding resin MR is cured by lowering the temperature of the molding resin MR. In this case, by using an existing thermoplastic resin, the resin substrate 2 can be molded at low cost.

[0054] Furthermore, when a thermoplastic resin is used as the molding resin MR, it is preferable that the temperature of the mold 10 when injecting the molding resin MR in the molding resin injection process (step S6) be above the melting point of the molding resin MR (thermoplastic resin). In this case, the molding resin MR injected into the mold 10 is properly melted and filled into the inside of the mold 10. As a result, a resin substrate 2 of uniform quality is molded inside the mold 10 (cavity 13). However, when resin molding, it is necessary to cool the molding resin MR after filling the mold 10 with it. Therefore, it is not necessary to set the temperature of the mold 10 so that the temperature of the molding resin MR is above the melting point of the molding resin MR. For this reason, the temperature of the mold 10 is set so that the temperature of the molding resin MR filled into the mold 10 is around room temperature (for example, 5°C or higher) to 60°C. In this embodiment, it is preferable that the temperature of the mold 10 when injecting the molding resin MR be in the range of 5°C to 60°C, that is, 5°C or higher and 60°C or lower.

[0055] Next, in this embodiment, the method for manufacturing a resin structure involves a casting removal step after the molding resin curing step in step S6. As shown in step S7 of Figure 3, the casting removal step involves removing the non-pneumatic tire (resin structure) 1 as a cast product. This creates a replica of the resin structure (1). Figure 9 shows the state in which the cast product (replica) of the non-pneumatic tire 1 has been removed by opening the divided molds 11 and 12 of the molding mold 10. Note that in Figure 9, the cast product of the non-pneumatic tire 1 is shown with the burrs formed by the gate 15 removed.

[0056] The resin structure manufacturing method according to this embodiment involves a casting method that includes a mother structure creation step (step S1), a mold creation step (step S2), a molding resin injection step (step S5), a molding resin curing step (step S6), and a cast product removal step (step S7) to manufacture the resin structure (1). In this case, by creating the mother structure F0 using an additive manufacturing method, the mother structure F0 used for molding a resin substrate 2 with a complex shape can be easily created. Therefore, according to the resin structure manufacturing method according to this embodiment, even if the design of the resin structure (1) is changed, the resin structure can be easily modified.

[0057] In this embodiment, the resin structure (1) is a non-pneumatic tire 1 comprising a resin base 2 and a tread member 3, where the resin base 2 is the tire body. In this case, it is possible to easily accommodate changes to the non-pneumatic tire having a resin base 2 with a complex structure having multiple shaped parts (21-23).

[0058] Furthermore, in the mother structure creation process (step S1) according to this embodiment, the additive manufacturing method can be any one of fused deposition modeling, sheet lamination, or stereolithography. In this case, by using an existing additive manufacturing method that is appropriate for the manufacturing environment, it is possible to easily accommodate changes to the resin substrate 2.

[0059] Furthermore, in the mold creation process (step S3) according to this embodiment, the mold 10 is created by molding using a silicone material. In this case, the mold 10 can be created in a shorter time while keeping costs down compared to using a metal mold.

[0060] As described above, exemplary embodiments of the present invention have been stated, but the present invention is not limited to these embodiments and can be modified in various ways without departing from the spirit of the invention. For example, referring to the flowchart in Figure 3, in the mother structure creation process (step S1), the mother structure F0 can be created by additive manufacturing of a resin substrate 2 with the tread member 3 pre-exteriorated. In this case, the master product creation process (step S3) can be omitted by treating the mother structure F0 created in the mother structure creation process (step S1) as the master product F1.

[0061] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. Each embodiment of the present invention is considered to be a technology that can contribute to "No. 9 - Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," among others. [Explanation of Symbols]

[0062] 1: Non-pneumatic tire (resin structure), 2: Resin substrate (tire body), 21: Inner cylinder shape, 22: Outer cylinder shape, 23: Connecting piece shape, 23a: Connecting plate, 3: Tread member, 3a: Tread surface, 4: Wheel, 41: Mounting cylinder part, 42: Outer cylinder part, 43: Connecting rib, 5: Axle, 6: Bolt, 10: Molding mold, 11: Split mold, 12: Split mold, 13: Cavity, 14: Recess, 15: Gate, F0: Mother structure, F1: Master product, MS: Silicone material, MR: Molding resin

Claims

1. A method for manufacturing a resin structure, comprising a resin substrate having multiple shaped parts, The mother structure creation process involves creating the mother structure using additive manufacturing methods, A molding die creation process, which involves creating a molding die by taking a mold based on the aforementioned mother structure, A molding resin injection step in which molding resin is injected into the molding die, A molding resin curing step in which the molding resin injected into the molding die is cured, A process of removing the cast product from the mold, A method for manufacturing a resin structure, including [the specified element].

2. The resin structure is a non-pneumatic tire comprising a tire body having an inner cylindrical shape portion that is fitted onto a wheel fixed to an axle, an outer cylindrical shape portion that surrounds the inner cylindrical shape portion, and a connecting piece shape portion that radially connects the inner cylindrical shape portion and the outer cylindrical shape portion, and a tread member fitted onto the outer cylindrical shape portion. The method for manufacturing a resin structure according to claim 1, wherein the resin substrate is the tire body.

3. The method for manufacturing a resin structure according to claim 1, wherein in the step of creating the mother structure, the additive manufacturing method is one of fused deposition modeling, sheet lamination, or stereolithography.

4. The method for manufacturing a resin structure according to claim 1, wherein in the mold making step, the mold is made by molding using a silicone material.

5. In the molding resin injection step, the molding resin injected into the mold is a thermosetting resin. A method for manufacturing a resin structure according to claim 1, wherein in the molding resin curing step, the molding resin is cured by heating the molding resin.

6. In the aforementioned molding resin injection step, the molding resin injected into the molding die is a thermoplastic resin. A method for manufacturing a resin structure according to claim 1, wherein in the molding resin curing step, the molding resin is cured by lowering the temperature of the molding resin.

7. A method for manufacturing a resin structure according to claim 6, wherein, in the molding resin injection step, the temperature of the mold when injecting the molding resin is 5°C or higher and 60°C or lower.

8. The method for manufacturing a resin structure according to claim 2, wherein in the step of creating the mother structure, the mother structure is a prototype used for molding the resin substrate, and in the step of creating the mold, the mold is created by performing the molding process with the mother structure fitted with a tread member as an exterior.

9. A method for manufacturing a resin structure according to claim 8, wherein in the molding resin injection step, a tread member is placed in the mold before the molding resin is injected.

10. A method for manufacturing a resin structure according to claim 9, wherein the tread member arranged in the molding die is subjected to a chlorination treatment on its radially inner surface.

11. A method for manufacturing a resin structure according to claim 9 or 10, wherein an adhesive is applied to the radially inner surface of the tread member placed in the molding die.

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