Structure for casting production

Abstract

The utility model provides a tubular structural body (1) for casting manufacturing, which is provided with a tubular main body part (20), the main body part (20) is provided with a main body part (11) and a female embedded part (12), the female embedded part (12) and the main body part (11) are continuously arranged, and the inner diameter of the female embedded part (12) is larger than the outer diameter of the main body part (11). The structure (1) for casting is provided with a main part inner surface covering layer (31) for covering the inner surface of the main part (11) and an outer surface covering layer (32) for covering the outer surface of the female fitting part (12). Preferably, the outer surface covering layer (32) covers the entire area of the outer surface of the female fitting part (12).

Description

Technical Field

[0001] The present utility model relates to a structure for casting manufacturing. Background Art

[0002] In the manufacture of castings, generally, casting sand is used to form a mold having a cavity inside, and a sprue cup, a sprue (downsprue), a runner (cross runner), and a weir (ingate) for supplying molten metal to the cavity are formed in a manner communicating with the cavity, and a vent hole, a feeding riser, and an overflow riser communicating with the outside are formed. Sometimes, a core is arranged in the cavity. The applicant has previously proposed a structure for casting manufacturing that can be used as a runner and a riser (Patent Documents 1 and 2). The structures for casting manufacturing described in Patent Documents 1 and 2 have a cylindrical main body portion and a covering layer formed on the inner surface of the main body portion.

[0003] In addition, Patent Document 3 describes a runner in which a refractory is fixed to the inner surface or the outer surface of a paper tube.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-70052

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-24841

[0008] Patent Document 3: Japanese Utility Model Publication No. 56-34834 Summary of the Invention

[0009] The present utility model relates to a cylindrical structure for casting manufacturing.

[0010] In one embodiment, it preferably has a cylindrical main body portion having a main trunk portion and a master mold fitting portion continuously provided with the main trunk portion and having an inner diameter equal to or larger than the outer diameter of the main trunk portion.

[0011] In one embodiment, it preferably has an inner surface covering layer of the main trunk portion covering the inner surface of the main trunk portion and an outer surface covering layer covering the outer surface of the master mold fitting portion.

[0012] In one embodiment, it preferably has a cylindrical main body portion having a male mold fitting portion fitted into the master mold fitting portion at one end of the main trunk portion.

[0013] In one embodiment, it is preferable that the outer diameter of the male mold fitting portion is equal to or smaller than the inner diameter of the master mold fitting portion.

[0014] In one embodiment, it is preferable to have a main body inner surface covering layer covering the inner surface of the above-mentioned main body portion and an outer surface covering layer covering the outer surface of the above-mentioned male fitting portion.

[0015] In addition, the present utility model relates to a method for manufacturing a cylindrical casting structure.

[0016] In one embodiment, preferably, the casting structure has a cylindrical main body portion, and the main body portion has a main trunk portion and a female fitting portion that is continuously provided with the main trunk portion and has an inner diameter equal to or greater than the outer diameter of the main trunk portion.

[0017] In one embodiment, it is preferable to have a main trunk coating step of coating a coating liquid on the inner surface of the main trunk portion to form a main trunk inner surface covering layer covering the inner surface of the main trunk portion.

[0018] In one embodiment, it is preferable to have a female fitting portion coating step of coating a coating liquid over the entire circumference of the outer surface of the female fitting portion to form an outer surface covering layer covering the outer surface of the female fitting portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a perspective view schematically showing a preferred embodiment of the casting structure of the present utility model.

[0020] Figure 2 (a) of Figure 1 is a sectional view taken along line IIa-IIa of Figure 2 (b) of Figure 1 is a sectional view taken along line IIb-IIb of Figure 2 (c) of Figure 1 is a sectional view taken along line IIc-IIc of

[0021] Figure 3 is schematically showing Figure 1 a perspective view of the state in which the casting structures shown are connected to each other.

[0022] Figure 4 is Figure 3 a partially enlarged sectional view of

[0023] Figure 5 is a schematic sectional view of a mold in which the casting structure shown in Figure 1 is internally accommodated.

[0024] Figure 6 (a) of Figure 2 is a sectional view schematically showing another preferred embodiment of the casting structure according to the present utility model, and is a view corresponding to Figure 6 (a) ofFigure 6 A partially enlarged cross-sectional view of the state where the structures for casting manufacture shown in (a) are connected to each other, corresponding to Figure 4 the figure of

[0025] Figure 7 (a) is a cross-sectional view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model, corresponding to Figure 2 the figure of (a) of Figure 7 (b) is schematically showing Figure 7 a partially enlarged cross-sectional view of the state where the structures for casting manufacture shown in (a) are connected to each other, corresponding to Figure 4 the figure of

[0026] Figure 8 (a) is a cross-sectional view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model, corresponding to Figure 2 the figure of (a) of Figure 8 (b) is schematically showing Figure 8 a partially enlarged cross-sectional view of the main part of the state where the structures for casting manufacture shown in (a) are connected to each other, corresponding to Figure 4 the figure of

[0027] Figure 9 (a) is a cross-sectional view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model, corresponding to Figure 2 the figure of (a) of Figure 9 (b) is schematically showing Figure 9 a partially enlarged cross-sectional view of the state where the structures for casting manufacture shown in (a) are connected to each other, corresponding to Figure 4 the figure of

[0028] Figure 10 (a) is a cross-sectional view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model, corresponding to Figure 2 the figure of (a) of Figure 10 (b) is schematically showing Figure 9 a partially enlarged cross-sectional view of the state where the structures for casting manufacture shown in (a) are connected to each other, corresponding to Figure 4 the figure of

[0029] Figure 11 is a partially enlarged cross-sectional view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model.

[0030] Figure 12 is a perspective view schematically showing another preferred embodiment of the structure for casting manufacture of the present utility model, corresponding toFigure 1 of the figure.

[0031] Figure 13 The (a) of Figure 12 is a cross-sectional view taken along XIIIa-XIIIa of Figure 13 The (b) of Figure 12 is a cross-sectional view taken along XIIIb-XIIIb of

[0032] Figure 14 is a schematic perspective view showing the state where the structures for casting manufacture shown in Figure 12 are connected to each other, and is a figure corresponding to Figure 3 of the figure.

[0033] Figure 15 is Figure 14 a magnified cross-sectional view of the main part of

[0034] Figure 16 The (a) of Figure 13 is a schematic cross-sectional view showing another preferred embodiment of the structure for casting manufacture of the present utility model, and is a figure corresponding to Figure 16 The (a) of Figure 16 is a magnified main part cross-sectional view showing the state where the structures for casting manufacture shown in the (a) of Figure 15 are connected to each other, and is a figure corresponding to

[0035] Figure 17 The (a) to (d) of Figure 2 are schematic perspective views showing modified examples of the structure for casting manufacture of the present utility model, and are figures corresponding to

[0036] Figure 18 The (a) to (e) of

[0037] Figure 19 are schematic cross-sectional views showing modified examples of a preferred embodiment of the manufacturing method of the structure for casting manufacture of the present utility model. Detailed implementation mode

[0038] The structure for casting manufacturing in Patent Document 1 has a cylindrical main body portion and a fitting portion connected to the main body portion. In the structure for casting manufacturing in this document, by inserting one end portion of the main body portion of an adjacent structure for casting manufacturing, which is on the side away from the fitting portion, into the fitting portion of another structure for casting manufacturing and making them fit together, a plurality of structures for casting manufacturing can be connected. In the structure for casting manufacturing in this document, by making the inner diameter of one end portion of the main body portion 1.0 mm or more smaller than the inner diameter of the other end portion, peeling of the covering layer during casting can be suppressed at the portion where adjacent structures for casting manufacturing are fitted together. However, there is room for improvement regarding the possibility that molten metal oozes out to the outside of the structure for casting manufacturing during casting, especially when the pressure of the molten metal inside the structure for casting manufacturing is high. This oozing of the molten metal is particularly likely to occur at the portion where adjacent structures for casting manufacturing are fitted together. There is also room for improvement regarding the structure for casting manufacturing in Patent Document 2.

[0039] In Patent Document 3, there is no description of the case where a structure formed by fitting a plurality of cylindrical structures for casting manufacturing is used as a runner, and there is no research on preventing the oozing of molten metal at the portion where adjacent structures for casting manufacturing are fitted together.

[0040] The present utility model relates to a structure for casting manufacturing that can prevent the oozing of molten metal during casting.

[0041] Hereinafter, the present utility model will be described based on its preferred embodiments.

[0042] Figure 1 A structure for casting manufacturing (hereinafter also simply referred to as "structure") 1 showing a preferred first embodiment of the structure for casting manufacturing of the present utility model.

[0043] The structure 1 is typically cylindrical. The "cylindrical" mentioned here includes a straight shape such as Figure 1 , a shape having a bent portion 17 in a part of the axial direction as shown in (a) of Figure 17 , a shape in which the entire axial direction is bent into an arc shape as shown in (b) of Figure 17 , a shape in which a cylindrical second portion 19 branches off from a cylindrical first portion 18 as shown in (c) and (d) of Figure 17 , etc. In addition, the "cylindrical" includes not only a cylindrical shape with a circular cross-section, that is, a circular cylinder, but also a cylindrical shape with a polygonal cross-section, that is, a square cylinder. The cross-sectional shape of the cylindrical structure orthogonal to the axial direction is typically circular, but it can also be elliptical. The cross-sectional shape of the square cylinder structure orthogonal to the axial direction is typically square, but it can also be a triangle, a rectangle, or a polygon with five or more sides, or a shape with chamfered corners of the polygon.

[0044] The structure 1 has a cylindrical main body portion 20. The main body portion 20 typically contains organic fibers, inorganic fibers, inorganic particles, and a binder. Each component contained in the main body portion 20 will be described later. The main body portion 20 is the part that constitutes the main body of the structure 1.

[0045] The main body portion 20 preferably has a main stem portion 11 and a female mold fitting portion 12 that is connected to the main stem portion 11 and has an inner diameter greater than or equal to the outer diameter of the main stem portion 11. The female mold fitting portion 12 may also be formed at one end 1a in the axial direction of the main stem portion 11. Figure 2 An example is shown. In Figure 2 In an example of the structure 1 shown, it is preferred that the inner diameter of the main body portion 20 is larger on the side of one end 1a in the axial direction Z than on the side of the other end 1b.

[0046] In addition, the female mold fitting portion 12 may also be formed by branching from the main stem portion 11. Figure 17 (d) of Figure 17 In an example of the structure 1 shown in (d) of Figure 17 it is preferred that the inner diameters of the ends 1c and 1d of the structure 1 other than the female mold fitting portion 12 are less than or equal to the inner diameter of the female mold fitting portion 12. In addition, in

[0047] In an example of the structure 1 shown in (d) of Figure 2 it is preferred that both the inner diameter and the outer diameter of the female mold fitting portion 12 are larger than those of the main stem portion 11. In an example of the structure 1 shown in

[0048] The structure 1 preferably enables connection of multiple identical or similar structures.

[0049] In Figure 1 In an example of the structure 1 shown, both ends of the main body portion 20 in the axial direction Z are open.

[0050] The outer diameter D1 of the end of the structure 1 other than the female mold fitting portion 12 is preferably less than or equal to the inner diameter D2 of the female mold fitting portion 12.

[0051] In Figure 1 and 2 In an example of the structure 1 shown, the end of the structure 1 other than the female mold fitting portion 12 is the end on the other end 1b side of the main stem portion 11 opposite to one end 1a in the axial direction Z.

[0052] In Figure 17In an example of the structure 1 shown in (d), the ends of the structure 1 other than the female mold fitting part 12 are the ends 1c and 1d of the first part 18. When the outer diameter D11 of the end 1c of the first part 18 is different from the outer diameter D12 of the end 1d of the first part 18, the above-mentioned outer diameter D1 is the smaller one of the outer diameter D11 and the outer diameter D12. It is possible that only one of the outer diameter D11 of the end 1c of the first part 18 and the outer diameter D12 of the end 1d of the first part 18 is equal to or less than the inner diameter D2 of the female mold fitting part 12, but it is more preferable that both the outer diameter D11 and the outer diameter D12 are equal to or less than the inner diameter D2.

[0053] In addition, in this specification, unless otherwise specified, the inner diameter and the outer diameter refer to the inner diameter and the outer diameter of the entire structure 1 including both the main body part and the covering layer covering the surface of the main body part.

[0054] The structure 1 is preferably capable of connecting the structures 1 to each other by inserting the ends of the structure 1 other than the female mold fitting part 12 into the female mold fitting part 12 of another structure 1 and making them fit. By connecting a plurality of structures 1 in a desired number, a long cylindrical body 10 of a desired length can be formed (see Figure 3 ).

[0055] The end of the structure 1 other than the female mold fitting part 12 is preferably a male mold fitting part 13 that is inserted into a female mold fitting part whose inner diameter is equal to or greater than the outer diameter of the main body part 11. In Figure 17 an example of the structure 1 shown in (d), it is possible that only one of the outer diameter D11 of the end 1c of the first part 18 and the end 1d of the first part 18 becomes the male mold fitting part 13, but it is more preferable that both the end 1c and the end 1d become the male mold fitting part 13.

[0056] The male mold fitting part 13 refers to the part that is inserted into the female mold fitting part 12 when the end of the structure 1 other than the female mold fitting part 12 is inserted into the female mold fitting part 12 of the same or the same type of structure 1. Specifically, the length L1 of the male mold fitting part 13 is the same as the depth L2 of the female mold fitting part 12. Here, "the same" includes not only the case where the length L1 of the male mold fitting part 13 and the depth L2 of the female mold fitting part 12 are the same, but also the case where they are approximately the same to the extent that the length L1 and the depth L2 are regarded as being substantially the same. Specifically, when the ratio of the length L1 of the male mold fitting part 13 to the depth L2 of the female mold fitting part 12 is preferably 80% or more and 120% or less, more preferably 90% or more and 110% or less, and further preferably 95% or more and 105% or less, the depth L2 and the length L1 are regarded as the same. Figure 2 In (a) of Figure 17 and (d) of

[0057] The length L1 of the male fitting portion 13 is Figure 2 In an example of the structure 1 shown, it is the length of the male fitting portion 13 along the axial direction Z of the main body portion 11. In Figure 17 In an example of the structure 1 shown in (d) of

[0058] In Figure 2 In an example of the structure 1 shown, it is preferable that the length L3 of the main body portion 11 in the axial direction Z is longer than the depth L2 of the female fitting portion 12. In Figure 2 In an example of the structure 1 shown, when the length L3 of the main body portion 11 in the axial direction Z is shorter than the depth L2 of the female fitting portion 12, or when the length L3 of the main body portion 11 and the depth L2 of the female fitting portion 12 are the same, substantially the entire main body portion 11 becomes the male fitting portion 13.

[0059] The structure 1 preferably has a main body inner surface covering layer 31 that covers the inner surface of the main body portion 11 and an outer surface covering layer (hereinafter, also referred to as "outer surface covering layer of the female fitting portion") 32 that covers the outer surface of the female fitting portion 12. Figure 2 (a) of

[0060] The main body inner surface covering layer 31 and the outer surface covering layer 32 preferably contain refractory inorganic particles selected from metal oxides and metal silicates, a binder, and clay minerals. Each component contained in the two covering layers 31 and 32 will be described later.

[0061] The main body inner surface covering layer 31 preferably continuously exists over the entire circumference in the circumferential direction of the structure 1. Figure 2 (b) of

[0062] In addition, the main body inner surface covering layer 31 preferably continuously exists over the entire region of the main body portion 11 in the axial direction Z. That is, it is preferable that the main body inner surface covering layer 31 covers the entire region of the inner surface of the main body portion 11. Figure 2 (a) of

[0063] When high-temperature molten metal flows into the structure 1 and the organic fibers, binders, etc. contained in the main body portion 20 undergo thermal decomposition, gas is generated from the casting sand. By having the main body inner surface covering layer 31, the structure 1 can prevent gas from invading into the structure 1. Thus, gas is not easily mixed into the molten metal flowing in the structure 1.

[0064] From the viewpoint of more significantly exerting this effect, the main body inner surface covering layer 31 preferably continuously exists over the entire circumference in the circumferential direction of the structure 1, and more preferably covers the entire region of the inner surface of the main body portion 11.

[0065] The outer surface covering layer 32 of the female mold fitting portion 12 preferably continuously exists over the entire circumference of the circumferential direction of the structure 1. In Figure 2 One example is shown in (c) of

[0066] In addition, the outer surface covering layer 32 preferably continuously exists over the entire area of the outer surface of the female mold fitting portion 12 in the axial direction Z. That is, the outer surface covering layer 32 preferably covers the entire area of the outer surface of the female mold fitting portion 12. In Figure 2 One example is shown in (a) of

[0067] The structure 1 can be used, for example, in the manufacture of castings as described below.

[0068] First, the structures 1 are connected to each other to form a cylindrical body 10. Then, as Figure 5 shown, the cylindrical body 10 is buried at a specified position in the casting sand to form a mold 40. In Figure 5 the example shown, the mold 40 is a sand mold. The structure is typically buried with a part of the opening remaining. Specifically, it is preferably buried in a state where the opening on the upstream side of the most upstream structure 1 among the plurality of structures 1 that are connected to form the cylindrical body 10 is exposed to the outside of the casting sand.

[0069] The method of burying the cylindrical body 10 is not particularly limited. For example, the casting sand can be arranged after the cylindrical body 10 is arranged at a specified position, or the cylindrical body 10 can be arranged after the casting sand is arranged in a specified state.

[0070] As the casting sand for the sand mold 40, the usual casting sand that has been used in the manufacture of such castings can be used without limitation.

[0071] Then, molten metal is poured into the mold 40 for casting. Specifically, the molten metal is injected from the pouring gate 41 provided at one end of the cylindrical body 10, and the molten metal is supplied into the cavity 42 for casting. At this time, the structure 1 maintains thermal strength, and since the thermal shrinkage due to thermal decomposition is small, cracks in each structure 1 and breakage of the structure 1 itself can be suppressed, and it is also not easy for the molten metal to embed in the structure 1 or for the casting sand, etc. to adhere.

[0072] After casting, it is cooled to a specified temperature, the sand box is disassembled to remove the casting sand, and then the structure for casting is removed by blasting treatment to expose the casting. After that, post-treatment such as finishing treatment is performed on the casting as needed to complete the manufacture of the casting.

[0073] The structure 1 is suitable for use as, for example, a runner or an exhaust runner used in casting.

[0074] In addition, the structure 1 is particularly suitable for use as a runner or an exhaust runner in the manufacture of cast steel. This is because, compared with cast iron, cast steel has a higher melting point, so the temperature of the molten metal during pouring is higher, and the kinematic viscosity is liable to become lower.

[0075] By means of the outer surface covering layer 32 having the master mold fitting portion 12, the structure 1 can prevent the molten metal from leaking out during pouring. Hereinafter, this will be described in detail.

[0076] When connecting the structures 1 to each other, it is difficult to make the end face 11e of the end portion other than the master mold fitting portion 12 in one structure 1, that is, the end face 11e of the male mold fitting portion 13 of one structure 1, closely contact the end face 12e disposed inside the master mold fitting portion 12 of the other structure 1 without any gap. Therefore, there may be a gap between the end face 11e of one structure 1 and the end face 12e of the other structure 1 (see Figure 4 ). In the illustrated example, the end face 12e of the master mold fitting portion 12 is the upper surface 12e of the step portion 15.

[0077] During pouring, the molten metal that has invaded into the above gap sometimes contacts the corner portion formed by the inner peripheral surface 12a of the master mold fitting portion 12 and the upper surface 12e of the step portion 15 (hereinafter, also referred to as the "corner portion of the master mold fitting portion"). As a result, there is a case where this corner portion is damaged and fine pores penetrating the master mold fitting portion 12 are generated. The molten metal flowing in the structure 1 may leak to the outside of the structure 1 through such fine pores.

[0078] However, by covering the outer surface of the master mold fitting portion 12 with the outer surface covering layer 32, it is possible to prevent the molten metal from penetrating through the master mold fitting portion 12 and leaking to the outside of the structure 1. Since the outer surface covering layer 32 covers the outer surface of the master mold fitting portion 12 as described above, there is no worry about peeling when the male mold fitting portion 13 is fitted into the master mold fitting portion 12. Therefore, the effect of preventing the molten metal from leaking out can be reliably achieved. From the viewpoint of more effectively preventing the molten metal from leaking out, it is preferable to further have a master mold fitting portion inner surface covering layer 33 that covers the inner surface of the master mold fitting portion 12. The master mold fitting portion inner surface covering layer 33 will be described later.

[0079] When the molten metal leaks out to the outside of the structure 1, the molten metal comes into contact with the casting sand, resulting in sintering of the casting sand mixed into the molten metal. Usually, when manufacturing a casting, there are a product part formed by solidification of the molten metal in the cavity of the sand mold and a part other than the product formed by solidification of the molten metal inside the runner pipe. By suppressing the mixing of the casting sand into the molten metal, the part other than the product can be easily reused. In addition, the process of removing the casting sand from the molten metal obtained by remelting the part other than the product can be omitted, so that the cost can be suppressed and the quality of the molten metal obtained by remelting the part other than the product can be stabilized.

[0080] The effect of preventing the molten metal from leaking out of the structure 1 during pouring is more significantly exerted when the inner diameter D3 of the main body part 11 in the structure 1 is large. Generally speaking, the leakage of the molten metal during pouring is likely to occur when the pressure of the molten metal in the structure 1 is high. When the cavity 42 of the mold 40 used for casting is large, the amount of the molten metal poured increases. In order to avoid a decrease in the temperature of the molten metal during pouring when pouring a large amount of molten metal, as the structure 1 constituting the cylindrical body 10 buried in the mold 40, a structure with a large inner diameter D3 of the main body part 11 that can increase the flow rate of the molten metal poured is preferably used. In addition, when the cavity 42 is relatively large, the mold 40 also becomes larger, so the vertical height of the cylindrical body 10 is also likely to become higher. Therefore, when the inner diameter D3 of the main body part 11 in the structure 1 is large, it is mostly used under the condition of high pressure of the molten metal. Specifically, when the inner diameter D3 of the other end part of the main body part 11, that is, the male mold fitting part 13, on the side opposite to the one end 1a side of the axial direction Z is 45 mm or more, it is assumed to be used under the condition of high pressure of the molten metal.

[0081] In the structure 1 of the present utility model, even when the inner diameter D3 of the main body part 11 in the structure 1 is large and the pressure of the molten metal in the main body part 11 is high, the leakage of the molten metal during pouring can be prevented. From the viewpoint of more significantly achieving the effect of preventing the leakage of the molten metal during pouring, the inner diameter D3 of the male mold fitting part 13 is preferably 65 mm or more, and more preferably 90 mm or more.

[0082] In addition, from the viewpoint of operability, the inner diameter D3 of the male mold fitting part 13 is preferably 700 mm or less, more preferably 550 mm or less, and further preferably 350 mm or less.

[0083] The outer surface covering layer 32 of the female mold fitting part 12 may not continuously exist in the circumferential direction of the structure 1, but from the viewpoint of effectively preventing the leakage of the molten metal, it is preferably continuously present throughout the entire circumference of the structure 1.

[0084] In addition, the outer surface covering layer 32 of the female mold fitting portion 12 may only cover a part of the outer surface of the female mold fitting portion 12 in the axial direction Z. However, from the viewpoint of effectively preventing the leakage of molten metal, it is preferable to cover the entire area of the outer surface of the female mold fitting portion 12 in the axial direction Z.

[0085] The outer surface covering layer 32 more preferably continuously exists over the entire circumference in the circumferential direction of the structure 1 and covers the entire area of the outer surface of the female mold fitting portion 12 in the axial direction Z. In other words, the outer surface covering layer 32 more preferably covers the entire area of the outer surface of the female mold fitting portion 12.

[0086] In the structure 1, as described above, it is preferable that the outer diameter D1 of the end portion of the structure 1 other than the female mold fitting portion 12 is equal to or less than the inner diameter D2 of the female mold fitting portion 12. Thereby, it is easy to insert the end portion of the structure 1 other than the female mold fitting portion 12 into the female mold fitting portion 12 of another structure 1, and it is possible to easily fit the two.

[0087] From the viewpoint of more easily inserting the end portion 13 of the structure 1 other than the female mold fitting portion 12, that is, the male mold fitting portion 13 of the structure 1, into the female mold fitting portion 12 of another structure 1, the ratio D1 / D2 of the outer diameter D1 to the inner diameter D2 is preferably 1 or less, more preferably 0.9999 or less, and further preferably 0.9995 or less.

[0088] In addition, when the male mold fitting portion 13 of the structure 1 is fitted to the female mold fitting portion 12 of another structure 1, from the viewpoint of preventing the gap between the outer surface of the male mold fitting portion 13 and the inner surface of the female mold fitting portion 12 from becoming too large and further stabilizing the fitting state of the two, the ratio D1 / D2 is preferably 0.9 or more, more preferably 0.95 or more, and further preferably 0.99 or more.

[0089] From the viewpoint of taking both of the above into consideration, the ratio D2 / D1 is preferably 0.9 or more and less than 1, more preferably 0.95 or more and 0.9999 or less, and further preferably 0.99 or more and 0.9995 or less.

[0090] In the structure 1, it is preferable that the outer diameter D4 of the female mold fitting portion 12 is the largest among the outer diameters of the structure 1. Thereby, when casting is performed in a state where a plurality of structures 1 are connected, the flow of molten metal can be made smooth.

[0091] In addition, in the structure 1, it is preferable that the inner diameter D2 of the female mold fitting portion 12 is the largest among the inner diameters of the structure 1. Thereby, when casting is performed in a state where a plurality of structures 1 are connected, the flow of molten metal can be made smooth.

[0092] Next, the structure 1 of the second to ninth preferred embodiments of the present utility model will be described. Regarding the second to ninth embodiments, the points different from the first embodiment will be described, and regarding the points not specifically described, the description of the first embodiment will be appropriately applied.

[0093] Figure 6 The structure 1 showing the second embodiment is shown.

[0094] The structure 1 preferably has a female mold fitting part inner surface covering layer 33 that covers the inner surface of the female mold fitting part 12. The inner surface of the female mold fitting part 12 includes the inner peripheral surface 12a of the female mold fitting part 12 and the upper surface 12e of the step part 15.

[0095] The female mold fitting part inner surface covering layer 33 preferably covers both the inner peripheral surface 12a and the upper surface 12e. In other words, the female mold fitting part inner surface covering layer 33 covers the entire area of the inner surface of the female mold fitting part 12. Figure 6 One example is shown in.

[0096] By having the female mold fitting part inner surface covering layer 33, the structure 1 can more effectively prevent the leakage of molten metal during casting. Hereinafter, this will be described in detail.

[0097] When connecting the structures 1 to each other, as described above, a gap sometimes occurs between the end surface 11e of one structure 1 and the end surface 12e disposed inside the other structure 1. By having the female mold fitting part inner surface covering layer 33, this gap can be reduced and it is difficult for this gap to form.

[0098] In addition, even if the above gap is generated and molten metal invades this gap, the female mold fitting part 12 can be protected. This is because the inner surface of the female mold fitting part 12, particularly the inner surface at the corner of the female mold fitting part, is covered by the female mold fitting part inner surface covering layer 33. Figure 6 One example is shown in.

[0099] The molten metal invading into the above gap may invade between the outer peripheral surface of the male mold fitting part 13 of one structure 1 and the inner peripheral surface 12a of the female mold fitting part 12 of the other structure 1. However, the inner peripheral surface 12a of the female mold fitting part 12 is also covered by the female mold fitting part inner surface covering layer 33, thereby preventing this invasion. This is because the female mold fitting part inner surface covering layer 33 is disposed between the outer peripheral surface of the male mold fitting part 13 of one structure 1 and the inner peripheral surface 12a of the female mold fitting part 12 of the other structure 1.

[0100] Even if molten metal invades between them, the female mold fitting part 12 can be protected. This is because the inner peripheral surface 12a of the female mold fitting part 12 is covered by the female mold fitting part inner surface covering layer 33.Figure 6 This represents one example.

[0101] The structure 1 preferably has not only the inner surface covering layer 33 of the female mold fitting part but also the outer surface covering layer 32 of the female mold fitting part 12. That is, preferably, both the inner surface and the outer surface of the female mold fitting part 12 are covered. This also helps to more effectively prevent the molten metal from leaking out of the structure 1 during casting.

[0102] From the viewpoint of more significantly achieving the effect of protecting the female mold fitting part 12, the inner surface covering layer 33 of the female mold fitting part preferably continuously exists over the entire circumference of the structure 1 and preferably covers the entire area of the inner surface of the female mold fitting part 12.

[0103] Preferably, the inner surface covering layer 33 of the female mold fitting part is continuous with the inner surface covering layer 31 of the main body part. Thereby, the inner surfaces of the female mold fitting part 12 and the main body part 11 can be protected without gaps.

[0104] The inner surface covering layer 33 of the female mold fitting part and the inner surface covering layer 31 of the main body part may also be discontinuous. For example, the inner surface covering layer 33 of the female mold fitting part and the inner surface covering layer 31 of the main body part may be separate.

[0105] More preferably, the entire area of the inner surface of the main body part 20 is covered by the inner surface covering layer 33 of the female mold fitting part and the inner surface covering layer 31 of the main body part. Thereby, the entire area of the inner surface of the main body part 20 can be protected, and thus the molten metal can be more effectively prevented from leaking out during casting.

[0106] Figure 7 This represents the structure 1 of the third embodiment.

[0107] The structure 1 preferably has an end face covering part (hereinafter, also referred to as the "end face covering part of the female mold fitting part") 34 that covers the outermost end face of the structure 1 covering the female mold fitting part 12.

[0108] The end face covering part 34 may cover only a part of the end face of the female mold fitting part 12 or may cover the entire area of the end face.

[0109] By having the end face covering part 34 of the female mold fitting part 12, the molten metal during casting can be more effectively prevented from leaking out of the structure 1. Hereinafter, this will be described in detail.

[0110] When connecting the structures 1 to each other, as described above, molten metal sometimes intrudes into the gap generated between the end face 11e of one structure 1 and the end face 12e of the other structure 1. After that, it sometimes intrudes between the inner surface of the mold fitting portion 12 of one structure 1 and the outer surface of the male mold fitting portion 13 of the other structure 1. Also, it is possible to seep out of the structure 1 from the end 1a side of one structure 1, that is, from the end face side of the mold fitting portion 12 of one structure 1. However, by covering the end face of the mold fitting portion 12 with the end face covering portion 34, it is possible to prevent molten metal from seeping out of the structure 1 from the end face side of the mold fitting portion 12 of the structure 1.

[0111] From the viewpoint of more significantly exerting this effect, the end face covering portion 34 preferably continuously exists over the entire circumference of the structure 1, and more preferably covers the entire area of the end face of the mold fitting portion 12.

[0112] In the structure 1 having the outer surface covering layer 32 of the mold fitting portion 12, the outer surface covering layer 32 and the end face covering portion 34 of the mold fitting portion 12 may not continuously exist. However, from the viewpoint of more effectively preventing the seepage of molten metal during pouring, it is preferable that the outer surface covering layer 32 and the end face covering portion 34 are continuous, and it is preferable to integrally form them.

[0113] Figure 8 shows the structure 1 of the fourth embodiment.

[0114] The structure 1 preferably has a main body outer surface covering layer 35 that covers the outer surface of the main body portion 11.

[0115] In addition, the structure 1 preferably has a main body inner surface covering layer 31.

[0116] The structure 1 more preferably covers both the inner surface and the outer surface of the main body portion 11. Figure 8 shows an example thereof.

[0117] By the structure 1 having the main body inner surface covering layer 31 and the main body outer surface covering layer 35, it is possible to effectively prevent the seepage of molten metal during pouring, particularly the seepage of molten metal penetrating through the main body portion 11. For example, even when the pressure of the molten metal in the structure 1 is high, it is possible to prevent the seepage of molten metal.

[0118] From the viewpoint of more significantly exerting this effect, the main body outer surface covering layer 35 preferably continuously exists over the entire circumference of the structure 1.

[0119] From the viewpoint of protecting the inner surfaces of the female fitting portion 12 and the main body portion 11 without gaps, in the structure 1 having the inner surface covering layer 33 of the female fitting portion, it is preferable that the inner surface covering layer 33 of the female fitting portion is continuous with the inner surface covering layer 31 of the main body portion, and it is more preferable that the two are integrally formed.

[0120] The outer surface covering layer 32 preferably extends to the inner surface of the main body portion 11 through the end surface of the female fitting portion 12. In other words, it is preferable that the outer surface covering layer 32 of the female fitting portion 12, the end surface covering portion 34 of the female fitting portion 12, the inner surface covering layer 33 of the female fitting portion, and the inner surface covering layer 31 of the main body portion are continuous.

[0121] In addition, the outer surface covering layer 35 of the main body portion also preferably extends to the inner surface of the main body portion 11 through the outer surface and the end surface of the female fitting portion 12. In other words, the structure 1 of the fourth embodiment has the outer surface covering layer 35 of the main body portion, the outer surface covering layer 32 of the female fitting portion 12, the end surface covering portion 34 of the female fitting portion 12, the inner surface covering layer 33 of the female fitting portion, and the inner surface covering layer 31 of the main body portion, and it is preferable that they are continuous.

[0122] The inner surface covering layer 31 of the main body portion and the inner surface covering layer 33 of the female fitting portion may also be formed separately. In this case, it is preferable that the inner surface covering layer 33 of the female fitting portion extends to the inner surface of the main body portion 11, and a part of it overlaps with the inner surface covering layer 31 of the main body portion. By overlapping a part of the inner surface covering layer 33 of the female fitting portion with the inner surface covering layer 31 of the main body portion, it is possible to suppress the molten metal from oozing out from the interface between the separately formed inner surface covering layer 31 of the main body portion and the inner surface covering layer 33 of the female fitting portion. Figure 9 One example is shown.

[0123] When a part of the inner surface covering layer 33 of the female fitting portion overlaps with the inner surface covering layer 31 of the main body portion, either one may be located inside in the radial direction of the structure 1. However, it is preferable that the inner surface covering layer 33 of the female fitting portion is located at a position closer to the inner side in the radial direction of the structure 1 than the inner surface covering layer 31 of the main body portion. By forming the positional relationship between the inner surface covering layer 33 of the female fitting portion and the inner surface covering layer 31 of the main body portion in such a positional relationship, it is possible to prevent the molten metal flowing from one end 1a side to the other end 1b side in the structure 1 from colliding with the end portion on the one end 1a side of the inner surface covering layer 31 of the main body portion, and it is possible to suppress the inner surface covering layer 31 of the main body portion from peeling off starting from the end portion on the one end 1a side during casting.

[0124] When a part of the inner surface covering layer 33 of the female mold fitting portion overlaps with the inner surface covering layer 31 of the main body portion, the thickness T1 of the overlapping portion is preferably thicker than either the thickness (hereinafter, also referred to as "the maximum thickness of the inner surface covering layer of the female mold fitting portion") T2 of the thickest portion in the inner surface covering layer 33 of the female mold fitting portion and the thickness (hereinafter, also referred to as "the maximum thickness of the inner surface covering layer of the main body portion") T3 of the thickest portion in the inner surface covering layer 31 of the main body portion. Examples of T1 to T3 are as shown in Figure 9 shown.

[0125] The inner surface covering layer 31 of the main body portion and the inner surface covering layer 33 of the female mold fitting portion preferably have a constant thickness. Here, having a constant thickness also includes cases of accidental minor thickness variations such as thickness variations that are inevitable in manufacturing.

[0126] The advantage of the above thickness T1 being thicker than the above thickness T2 is as follows. When connecting and casting a plurality of structures 1, at the connection portion between the structures 1, the flow of the molten metal is likely to be disordered. By making the above thickness T1 thicker than the above thickness T2, at the above connection portion, it is possible to prevent the flow of the molten metal flowing in the structure 1 from being disordered, and it is possible to suppress the collision of the molten metal with the corner portion of the female mold fitting portion 12. Therefore, the corner portion of the female mold fitting portion 12 can be protected.

[0127] The advantage of the above thickness T1 being thicker than the above thickness T3 is as follows. Generally, during casting, the molten metal is made to flow from one end 1a side of the structure 1 provided with the female mold fitting portion 12 to the other end 1b side. By making the above thickness T1 thicker than the above thickness T3, it is possible to prevent the molten metal flowing in the structure 1 from colliding with the end portion on the one end 1a side of the inner surface covering layer 31 of the main body portion. Thereby, the inner surface covering layer 31 of the main body portion can be protected during casting.

[0128] From the viewpoint of protecting the corner portion of the female mold fitting portion 12, the ratio T1 / T2 of the above thickness T1 to the above thickness T2 is preferably more than 1, more preferably 1.5 or more, and further preferably 2 or more.

[0129] In addition, from the viewpoint of protecting the inner surface covering layer 33 of the female mold fitting portion from the friction effect when connecting the structures 1 to each other, the above ratio T1 / T2 is preferably 15 or less, more preferably 10 or less, and further preferably 5 or less.

[0130] From the viewpoint of taking both of the above into account, the above ratio T1 / T2 is preferably greater than 1 and 15 or less, more preferably 1.5 or more and 10 or less, and further preferably 2 or more and 5 or less.

[0131] From the viewpoint of protecting the inner surface covering layer 31 in the main body part during casting, the ratio T1 / T3 of the above-mentioned thickness T1 to the above-mentioned thickness T3 is preferably more than 1, more preferably 1.1 or more, and further preferably 1.2 or more.

[0132] In addition, from the viewpoint of smoothly flowing the molten metal at the connecting part between the structures 1 during casting, the ratio T1 / T3 is preferably 5 or less, more preferably 3 or less, and further preferably 2 or less.

[0133] From the viewpoint of taking both of the above into account, the ratio T1 / T3 is preferably more than 1 and 5 or less, more preferably 1.1 or more and 3 or less, and further preferably 1.2 or more and 2 or less.

[0134] The maximum thickness T2 of the inner surface covering layer 33 of the master mold fitting part is preferably thinner than the maximum thickness T3 of the inner surface covering layer 31 of the main body part. Thereby, it is possible to easily insert and fit the end part on the other end 1b side of the other structure 1 into the master mold fitting part 12 of the structure 1.

[0135] From the viewpoint of making it easier to fit the end part on the other end 1b side of the other structure 1 into the master mold fitting part 12 of the structure 1, the ratio T2 / T3 of the above-mentioned thickness T2 to the above-mentioned thickness T3 is preferably less than 1, more preferably 0.8 or less, and further preferably 0.5 or less.

[0136] In addition, from the viewpoint of protecting the main body part 20 in the master mold fitting part 12, the ratio T2 / T3 is preferably 0.01 or more, more preferably 0.05 or more, and further preferably 0.1 or more.

[0137] From the viewpoint of taking both of the above into account, the ratio T2 / T3 is preferably 0.01 or more and less than 1, more preferably 0.05 or more and 0.8 or less, and further preferably 0.1 or more and 0.5 or less.

[0138] The thicknesses of the inner surface covering layer 31 of the main body part and the inner surface covering layer 33 of the master mold fitting part do not necessarily have to be constant. Figure 10 An example of the structure 1 showing that the thickness of the inner surface covering layer 31 of the main body part is not a constant value.

[0139] When the thickness of the inner surface covering layer 31 of the main body part is not a constant value, the inner surface covering layer 31 of the main body part preferably has a portion that is thicker than a portion 31a of the inner surface covering layer 31 of the main body part disposed on the end 1a side in the axial direction Z of the main body part 11. By forming such a structure, the molten metal flowing inside the cylindrical body 10 obtained by connecting the structures 1 to each other passes through the main body part 11 of the structure 1 on the upstream side in the flow direction Z1 of the molten metal and enters the main body part 11 of the structure 1 on the downstream side in the direction Z1. The flow of the molten metal is not likely to directly collide with the surface of the inner surface covering layer 31 of the main body part that covers the end portion on the end 1a side of the main body part 11 of the downstream structure 1. Therefore, it is possible to prevent an impact from being applied to the end portion on the end 1a side of the main body part 11 of the downstream structure 1 and protect the inner surface covering layer 31 of the main body part. From the viewpoint of more significantly exerting this effect, the thickness of the above-mentioned portion 31a of the inner surface covering layer 31 of the main body part is preferably the thinnest.

[0140] The inner surface covering layer 31 of the main body part preferably has a gradually increasing thickness from the end 1a side to the end 1b side in the axial direction Z. Figure 10 This shows an example.

[0141] In addition, when the inner surface covering layer 31 of the main body part and the inner surface covering layer 33 of the master mold fitting part are formed separately, the positions of the end edges on the base end side in the continuous setting direction Y of the inner surface covering layer 33 of the master mold fitting part and the outer surface covering layer 32 may or may not be the same. From the viewpoint of being able to simply manufacture the structure 1 having the inner surface covering layer 33 of the master mold fitting part and the outer surface covering layer 32, it is preferable that the position of the end edge 33b on the base end side in the inner surface covering layer 33 of the master mold fitting part is the same as the position of the end edge 32b on the base end side in the outer surface covering layer 32.

[0142] Here, the positions of the end edge 33b of the inner surface covering layer 33 of the master mold fitting part and the end edge 32b of the outer surface covering layer 32 being the same not only includes the case where the positions of the two in the continuous setting direction Y of the master mold fitting part 12 are completely the same, but also includes the case where the positions of the two are approximately regarded as being substantially the same. Specifically, when the ratio of the distance L5 between the end edge 33b of the inner surface covering layer 33 of the master mold fitting part and the end edge 32b of the outer surface covering layer 32 in the continuous setting direction Y to the length L4 of the outer surface of the master mold fitting part 12 in the continuous setting direction Y is preferably 20% or less, more preferably 10% or less, and further preferably 5% or less, the position of the end edge 33b of the inner surface covering layer 33 of the master mold fitting part is regarded as being the same as the position of the end edge 32b of the outer surface covering layer 32. Figure 11 Examples of the length L4 and the distance L5 are shown.

[0143] In addition, in the structure 1, it is also preferable that the thickness of the inner surface covering layer 33 of the master mold fitting portion in the covering layer covering the surface of the main body portion 20 is the thinnest. In other words, it is preferable that the thickness of the inner surface covering layer 33 of the master mold fitting portion is thinner than the thickness of the covering layer other than the inner surface covering layer 33 of the master mold fitting portion. By forming such a structure, it is easy to insert the end portion of the structure 1 other than the master mold fitting portion 12 into the master mold fitting portion 12, and it is possible to easily fit the two. In addition, even when the coating film layer peels off when the male mold fitting portion 13 is fitted into the female mold fitting portion 12, the peeling amount can be reduced, and the influence on the product quality can be reduced.

[0144] Figure 12 The structure 1B of the fifth embodiment is shown.

[0145] The structure 1B preferably has a cylindrical main body portion 20.

[0146] The main body portion 20 preferably has a male mold fitting portion 13 at one end portion of the main trunk portion 11.

[0147] The male mold fitting portion 13 is preferably fitted inside the female mold fitting portion. The outer diameter of the male mold fitting portion 13 is preferably equal to or less than the inner diameter of the female mold fitting portion.

[0148] The structure 1B preferably has a female mold fitting portion 12 with an inner diameter equal to or greater than the outer diameter of the main trunk portion 11 continuously provided at the other end portion of the main trunk portion 11.

[0149] The female mold fitting portion 12 preferably has both an inner diameter and an outer diameter larger than those of the main trunk portion 11. Typically, a stepped portion 15 protruding outward in the radial direction of the main trunk portion 11 is formed at the end portion of the main trunk portion 11 on the side of the female mold fitting portion 12, and the female mold fitting portion 12 is continuously provided with the main trunk portion 11 via the stepped portion 15.

[0150] The structure 1B preferably can connect a plurality of identical or similar structures.

[0151] In Figure 12 In the structure 1B of the example shown, both ends of the main body portion 20 in the axial direction Z are open.

[0152] The inner diameter of the female mold fitting portion 12 is preferably equal to or greater than the outer diameter of the main trunk portion 11 on the side of the male mold fitting portion 13.

[0153] The structure 1B is preferably fitted by inserting the male mold fitting portion 13 of the structure 1B into the female mold fitting portion 12 of another structure 1B, so that the structures 1B can be connected to each other. By connecting a desired number of the structures 1B, a long cylindrical body 10 with a required length can be formed. Figure 14 An example is shown.

[0154] The structure 1B preferably has an inner surface covering layer 31 of the main body portion and an outer surface covering layer (hereinafter, also referred to as "outer surface covering layer of the male fitting portion") 36 that covers the outer surface of the male fitting portion 13.

[0155] The outer surface covering layer 36 of the male fitting portion 13 preferably contains refractory inorganic particles selected from metal oxides and metal silicates, a binder, and clay minerals. Each component contained in the outer surface covering layer 36 will be described later.

[0156] The inner surface covering layer 31 of the main body portion preferably continuously exists over the entire circumference in the circumferential direction of the structure 1B. Figure 13 One example is shown in (b) of.

[0157] The inner surface covering layer 31 of the main body portion preferably continuously exists over the entire region of the main body portion 11 in the axial direction Z. That is, in the structure 1B, the inner surface covering layer 31 also covers the entire region of the inner surface of the main body portion 11. Figure 13 One example is shown in (a) of.

[0158] By having the inner surface covering layer 31 of the main body portion, it is difficult for gas to mix into the molten metal flowing inside the structure 1B. From the viewpoint of more significantly exerting this effect, the inner surface covering layer 31 of the main body portion preferably continuously exists over the entire circumference in the circumferential direction of the structure 1B, and more preferably covers the entire region of the inner surface of the main body portion 11.

[0159] The outer surface covering layer 36 preferably covers the entire region of the outer surface of the male fitting portion 13.

[0160] The structure 1B of the fifth embodiment can also be used for manufacturing castings in the same manner as the structure 1 of the first embodiment.

[0161] By having the outer surface covering layer 36 of the male fitting portion 13, the structure 1B can prevent the molten metal from leaking out of the structure 1B during pouring. Hereinafter, this will be described in detail.

[0162] When the structures 1B are connected to each other, a gap may sometimes form between the end face 11e of the male fitting portion 13 of one structure 1B and the end face 12e located inside the female fitting portion 12 of the other structure 1B. Molten metal that enters this gap could potentially enter between the outer peripheral surface 11b of the male fitting portion 13 of one structure 1B and the inner peripheral surface 12a of the female fitting portion 12 of the other structure 1B. However, in the structures 1B, the molten metal is prevented from entering between the outer peripheral surface 11b and the inner peripheral surface 12a. This is because the outer peripheral surface 11b of the male fitting portion 13 is also covered by the outer surface covering layer 36. Furthermore, the outer surface covering layer 36 of the male fitting portion 13 is located between the outer peripheral surface 11b of the male fitting portion 13 of one structure 1B and the inner peripheral surface 12a of the female fitting portion 12 of the other structure 1B.

[0163] Furthermore, the structure 1B preferably includes an outer surface covering layer 36 of the male fitting portion 13 and a trunk inner surface covering layer 31, thereby covering the outer and inner surfaces of the male fitting portion 13. This effectively prevents molten metal from penetrating the male fitting portion 13 and leaking out during pouring.

[0164] The outer surface covering layer 36 of the male fitting portion 13 may be discontinuous in the circumferential direction of the structure 1B, but is preferably continuous over the entire circumference of the structure 1B from the viewpoint of effectively preventing the leakage of molten metal.

[0165] In the fifth embodiment, as described above, the trunk inner surface covering layer 31 covers the entire inner surface of the trunk 11. This protects the entire inner surface of the main body 20, thereby more effectively preventing molten metal from seeping out during pouring.

[0166] In the structure 1B of the fifth embodiment, similarly to the structure 1 of the first embodiment, when the inner diameter D3 of the trunk portion 11 of the structure 1 is large, the effect of more effectively preventing the molten metal from seeping out during pouring is more significantly achieved.

[0167] The preferred numerical range of the inner diameter D3 of the male fitting portion 13 of the fifth embodiment is the same as that of the first embodiment.

[0168] Figure 16 A structure 1B according to the sixth embodiment is shown.

[0169] The structure 1B preferably includes an outer surface covering layer 36 of the male fitting portion 13 and an end face covering portion (hereinafter also referred to as "male fitting portion end face covering portion") 37 that covers the end face 11e of the male fitting portion 13. The end face covering portion 37 may cover only a portion of the end face of the male fitting portion 13 or may cover the entire area of the end face.

[0170] By means of the end face covering portion 37 having the male fitting portion 13, it is possible to more effectively prevent the molten metal from leaking out during casting. Hereinafter, this will be described in detail.

[0171] When connecting the structures 1B to each other, as described above, sometimes a gap is generated between the end face 11e of the male fitting portion 13 of one structure 1B and the end face 12e of the other structure 1B disposed inside the female fitting portion 12. The structure 1B can reduce this gap and make it difficult to form this gap by having the end face covering portion 37 of the male fitting portion 13. Figure 16 One example is shown therein.

[0172] When the structure 1B has the outer surface covering layer 36 of the male fitting portion 13, the outer surface covering layer 36 and the end face covering portion 37 of the male fitting portion 13 may not be continuous. However, from the viewpoint of more effectively preventing the molten metal from leaking out during casting, it is preferable that the outer surface covering layer 36 and the end face covering portion 37 are continuous, and it is preferable that they are integrally formed.

[0173] When the structure 1B has the inner surface covering layer 31 of the main body portion, the end face covering portion 37 of the male fitting portion 13 is preferably continuous with the inner surface covering layer 31 of the main body portion, and they are preferably integrally formed.

[0174] The outer surface covering layer 36 of the male fitting portion 13 preferably extends to the inner surface of the main body portion 11 through the end face of the male fitting portion 13.

[0175] The outer diameter D1 of the male fitting portion 13 is preferably equal to or less than the inner diameter D2 of the end portion on the other end side of the main body portion 11 opposite to the one end side in the axial direction Z, that is, the inner diameter D2 of the female fitting portion 12. Thus, it is easy to insert the male fitting portion 13 of the structure 1B into the female fitting portion 12 of another structure 1B, and it is possible to easily fit the two.

[0176] The preferred numerical range of the ratio D1 / D2 of the above outer diameter D1 to the above inner diameter D2 is the same as the preferred numerical range of the ratio D1 / D2 in the first embodiment.

[0177] The inner surface covering layer 31 of the main body portion is preferably disposed at the innermost position in the radial direction of the structures 1 and 1B in the portion where the inner surface covering layer 31 of the main body portion is disposed. Thus, the inner surface covering layer 31 of the main body portion in the structures 1 and 1B comes into contact with the molten metal passing through the inside of the structures 1 and 1B, so it is easy to protect the main body portion 20 of the structures 1 and 1B.

[0178] In Figure 1In an example of the structure 1 shown, the radial direction of the structure 1 in the portion where the inner surface covering layer 31 of the main body part is disposed is the radial direction in a cross section orthogonal to the axial direction Z of the structure 1. Further, in Figure 17 In an example of the structure 1 shown in (d) of Figure 17 , in the radial direction of the structure 1 in the portion where the inner surface covering layer 31 of the main body part is disposed, when the inner surface covering layer 31 of the main body part is disposed in the first part 18, it is the radial direction of a cross section orthogonal to the axial direction Zx of the first part 18, and when the inner surface covering layer 31 of the main body part is disposed in the female mold fitting part 12, it is the radial direction of a cross section orthogonal to the axial direction Zy of the second part 19, that is, the continuous setting direction Y of the female mold fitting part 12.

[0179] The outer surface covering layer 32 of the female mold fitting part 12 is preferably disposed at the outermost position in the radial direction in a cross section orthogonal to the axial direction Z of the structure 1. Thereby, it is possible to achieve both simplicity in manufacturing and protection of the main body part 20.

[0180] The main body part 20 may also have a laminated structure in which two or more layers are laminated. However, from the viewpoint of easy manufacturing, the main body part 20 preferably has a single-layer structure.

[0181] The main body part 20 is preferably a structure formed integrally in the circumferential direction. Thereby, since the main body part 20 is a structure continuously present over the entire circumference in the circumferential direction, it is possible to prevent gaps and holes from being generated in the main body part 20, and it is possible to effectively prevent molten metal from leaking out during casting.

[0182] The structures 1 and 1B preferably have a portion on the outer surface of the main body part 20 that is not covered by the covering layers 32, 35, and 36. During casting, since molten metal flows into the structure 1, gas is generated when organic fibers, adhesives, etc. contained in the main body part 20 decompose thermally. A portion of the outer surface of the main body part 20 is not covered by the covering layers 32, 35, and 36, whereby the gas can be preferentially discharged from this portion to the casting sand side, that is, to the outside of the structures 1 and 1B.

[0183] It is also possible to have a portion on the outer surface of any one of the main body part 11, the male mold fitting part 13, and the female mold fitting part 12 of the main body part 20 that is not covered by the covering layers 32, 35, and 36. From the viewpoint of effectively achieving the effect of preferentially discharging gas to the outside of the structures 1 and 1B, it is preferable that there is a portion on the outer surface of the main body part 11 in the main body part 20 that is not covered by the main body part outer surface covering layer 35.

[0184] From the viewpoint of preferentially discharging gas to the outside of the structures 1 and 1B, the ratio of the area of the portion not covered by the outer surface covering layer 35 of the main body portion to the total area S1 of the outer surface of the main body portion 11, that is, the non-coverage area ratio, is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more.

[0185] From the viewpoint of preventing molten metal from leaking out of the structure 1 during casting, the non-coverage area ratio is preferably 100% or less, more preferably 95% or less, and still more preferably 90% or less.

[0186] From the viewpoint of taking both of the above into account, the non-coverage area ratio is preferably 30% or more and 100% or less, more preferably 50% or more and 95% or less, and still more preferably 70% or more and 90% or less.

[0187] Next, the constituent materials of the structures 1 and 1B will be described.

[0188] The main body portion 20 typically contains organic fibers, inorganic fibers, inorganic particles (hereinafter also referred to as first inorganic particles), and a binder (hereinafter also referred to as first binder).

[0189] The main body portion 20 is typically manufactured by the following method. First, a slurry-like composition (hereinafter referred to as raw material slurry) containing organic fibers, inorganic fibers, first inorganic particles, first binder, and a dispersion medium is prepared. Next, an intermediate formed body of the main body portion 20, for example, the main body portion in a water-containing state, is formed by using a mold for papermaking / dehydration forming. Next, the intermediate formed body is heated and dried using a mold, whereby the main body portion 20 can be formed.

[0190] The organic fibers are wound around the inorganic fibers and inorganic particles in the state before casting in the main body portion 20 and exhibit the effect of maintaining the shapes of the structures 1 and 1B. During casting, due to the heat of the molten metal, part or all of them burn.

[0191] The organic fibers can be one or more selected from pulp fibers, synthetic fibers, regenerated fibers (such as rayon fibers), etc.

[0192] Among these fibers, pulp fibers are preferably included. The reason is that they can be formed into various shapes by papermaking, the strength characteristics of the formed body after dehydration and drying are excellent, the pulp fibers are easily and stably obtained, and they are economical.

[0193] The pulp fibers can be one or more selected from wood pulp, cotton pulp, cotton linter pulp, non-wood pulp such as bamboo or straw. In addition, one or more selected from virgin pulp or waste paper pulp (recycled products) can be used.

[0194] From the viewpoints of ease of acquisition, environmental protection, reduction of manufacturing costs, etc., it is preferable to contain waste paper pulp such as waste newspapers.

[0195] The inorganic fibers are mainly used in the main body portion 20 to increase the strength of the structures 1 and 1B in the state before casting. They also maintain their shape without being burned by the heat of the molten metal during casting. Especially in the case of using the organic binder described later, the inorganic fibers can suppress the combustion of the organic fibers caused by the heat of the molten metal and the thermal shrinkage caused by the thermal decomposition of the organic binder.

[0196] As the inorganic fibers, one or more selected from carbon fibers, artificial mineral fibers such as rock wool, ceramic fibers, glass fibers, and natural mineral fibers can be used.

[0197] Among them, from the viewpoint of suppressing the above-mentioned thermal shrinkage, it is preferable to contain carbon fibers that have high strength even at the high temperature of metal melting.

[0198] From the viewpoint of suppressing manufacturing costs, it is preferable to contain one or more selected from rock wool and glass fibers.

[0199] As the first inorganic particles, one or more selected from aggregate particles of refractories such as mullite, graphite, mica, silica, hollow ceramics, and fly ash can be used.

[0200] From the viewpoint of improving the air permeability of the main body portion 20, the average particle size of the first inorganic particles is preferably 10 μm or more, more preferably 15 μm or more.

[0201] In addition, from the viewpoint of improving the formability of the main body portion 20, the average particle size of the first inorganic particles is preferably 100 μm or less.

[0202] If the average particle size of the first inorganic particles is above the above lower limit, the air permeability of the main body portion 20 becomes better, and the gas pressure in the mold during casting is appropriately reduced. In addition, by improving the air permeability of the main body portion 20, the voids between the materials of the main body portion 20 increase, the permeability of the coating liquid composition described later to the main body portion 20 is improved, and the covering layer is not easily peeled off from the main body portion 20.

[0203] If the average particle size of the first inorganic particles is below the above upper limit, the inorganic particles are not easily detached from the surface of the main body portion 20, and the formability becomes better.

[0204] From the viewpoint of raw material dispersibility, the apparent specific gravity of the first inorganic particles is preferably 0.5 or more, more preferably 2.8 or more.

[0205] In addition, from the viewpoint of weight reduction, the apparent specific gravity of the first inorganic particles is preferably 3 or less, more preferably 2.8 or less, and further preferably 2.5 or less.

[0206] The apparent specific gravity refers to the specific gravity of hollow particles when the volume of the hollow part inside the hollow particles is assumed to be a part of the volume of the hollow particles, and is consistent with the true specific gravity in the case of solid particles without an internal hollow part.

[0207] By making the apparent specific gravity of the first inorganic particles within the above range, the raw material dispersibility in the papermaking process when the dispersion medium is water becomes good. In addition, the weight of the formed main body 20 can be reduced, so the operability is improved.

[0208] In addition, the composition of the main body 20 can be determined in consideration of the volume specific gravity together with the apparent specific gravity of the first inorganic particles. The volume specific gravity means that when particles are placed in a container with a certain volume in a certain state, the amount of particles entering the container is measured, and the mass per unit volume is obtained.

[0209] The first inorganic particles can also be hollow. By using hollow particles, the apparent specific gravity of the first inorganic particles can be reduced.

[0210] In the present utility model, as the first binder, one or more selected from organic binders and inorganic binders can be used.

[0211] From the viewpoint of excellent removability after casting, it is preferable to contain an organic binder.

[0212] As the organic binder, one or more selected from thermosetting resins such as phenolic resin, epoxy resin, and furan resin can be used.

[0213] Among them, from the aspects of less generation of combustible gas, having a combustion inhibition effect, and a high residual carbon rate after thermal decomposition (carbonization), it is preferable to contain phenolic resin.

[0214] As the phenolic resin, one or more selected from novolac phenolic resin, resol phenolic resin type phenolic resin, modified phenolic resin modified with urea, melamine, epoxy, etc. can be used.

[0215] Among them, by containing resol phenolic resin type phenolic resin, no curing agent such as acid or amine is required, and the odor during the formation of the main body 20 and the casting defects when the main body 20 is used as a mold can be reduced, so it is preferable.

[0216] In the case of using novolac phenolic resin, it is preferable to use a curing agent in combination. Since this curing agent is easily soluble in water, it is preferably applied to the surface of the main body 20 after dehydration. As the curing agent, hexamethylenetetramine etc. are preferably used.

[0217] As the inorganic binder, one or more selected from phosphoric acid-based binders, water glass such as silicates, gypsum, sulfates, silica-based binders, and silicone-based binders can be used.

[0218] As the dispersion medium used in the raw material slurry, one or more selected from solvents such as water, ethanol, methanol, dichloromethane, acetone, and xylene can be used.

[0219] Among them, from the viewpoint of ease of operation, it is preferably water-containing.

[0220] In addition to containing organic fibers, inorganic fibers, first inorganic particles, and first binder, the main body portion 20 may further contain a paper strength reinforcing material. The paper strength reinforcing material has the function of maintaining the shape of the intermediate formed body.

[0221] As the paper strength reinforcing material, one or more selected from latex, acrylic emulsions, polyvinyl alcohol, carboxymethyl cellulose, polyacrylamide resins, polyamide epichlorohydrin resins, etc. can be used.

[0222] The inner surface covering layer 31 of the main body portion, the outer surface covering layer 32 of the female mold fitting portion 12, the inner surface covering layer 33 of the female mold fitting portion, the end face covering portion 34 of the female mold fitting portion 12, the outer surface covering layer 35 of the main body portion, the outer surface covering layer 36 of the male mold fitting portion 13, and the end face covering portion 37 of the male mold fitting portion 13 (hereinafter, sometimes collectively referred to as "covering layers") can typically be formed by applying a coating liquid composition containing refractory inorganic particles (hereinafter, also referred to as second inorganic particles) having an average particle size of 1 μm or more and 100 μm or less selected from metal oxides and metal silicates, a binder (hereinafter, also referred to as second binder), and clay minerals to the surface of the main body portion 20.

[0223] Regarding the refractory inorganic particles, the refractoriness means a melting point of 1500 °C or higher, preferably 1600 °C or higher, and more preferably 1700 °C or higher.

[0224] The second inorganic particles can be one or more selected from metal oxides and metal silicates.

[0225] Specifically, one or more selected from mullite, zircon, zirconia, alumina, olivine, spinel, magnesia, chromite, etc. can be used.

[0226] From the viewpoint of improving the gas defects of the casting, zircon is preferably included.

[0227] In cast steel with a carbon content lower than that of cast iron, it is preferable to include aggregate particles other than carbonaceous ones, and more preferably to include zircon having a high melting point and low wettability with molten metal.

[0228] From the viewpoints of the sealing property of the surface of the main body portion 20, the close adhesion between the main body portion 20 and the covering layer, etc., the average particle diameter of the second inorganic particles is preferably 1 μm or more, more preferably 3 μm or more.

[0229] In addition, the average particle diameter of the second inorganic particles is preferably 100 μm or less, more preferably 70 μm or less, and further preferably 40 μm or less.

[0230] In the structures 1 and 1B, from the viewpoint of the sealing property of the surface of the main body portion 20, the ratio of the average particle diameter of the first inorganic particles contained in the main body portion 20 to the average particle diameter of the second inorganic particles contained in the covering layer, calculated as [average particle diameter of the first inorganic particles] / [average particle diameter of the second inorganic particles], is preferably 0.1 or more, more preferably 0.5 or more, and further preferably 0.8 or more.

[0231] In addition, the ratio of the average particle diameter of the first inorganic particles contained in the main body portion 20 to the average particle diameter of the second inorganic particles contained in the covering layer, calculated as [average particle diameter of the first inorganic particles] / [average particle diameter of the second inorganic particles], is preferably 35 or less, more preferably 30 or less, further preferably 20 or less, and particularly preferably 6 or less.

[0232] In the structures 1 and 1B, the proportion of the second inorganic particles in the covering layer is preferably 50% by mass or more and less than 100% by mass, more preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 90% by mass or more.

[0233] From the viewpoints of improving the thermal strength and imparting the viscosity during coating, the covering layer preferably contains a clay mineral. By mixing the clay mineral into the dispersion liquid (coating liquid composition) for obtaining the covering layer, an appropriate viscosity is imparted to the dispersion liquid, sedimentation of the raw materials in the dispersion liquid is prevented, and the raw material dispersibility is improved.

[0234] As the clay mineral, one or more selected from phyllosilicate minerals, double-chain structure type minerals, etc. can be used. They can be natural or synthetic.

[0235] As the phyllosilicate mineral, one or more selected from clay minerals belonging to the montmorillonite group, kaolin group, illite group, such as bentonite, montmorillonite, lithium montmorillonite, activated clay, kibushi clay, zeolite, etc. can be used.

[0236] As the double-chain structure type mineral, one or more selected from attapulgite, sepiolite, palygorskite, etc. can be used.

[0237] From the viewpoints of improving the thermal strength and ensuring the viscosity during coating, it is preferable to use one or more selected from attapulgite, sepiolite, bentonite, and montmorillonite, and more preferably to use one or more selected from attapulgite and sepiolite.

[0238] In terms of the clay mineral having a layered structure or a double-chain structure, for example, mainly including a hexagonal closest-packed structure, it is different from refractory inorganic particles that generally do not form a layered structure or a double-chain structure.

[0239] With respect to 100 parts by mass of the refractory inorganic particles, the content of the clay mineral is preferably 0.5 part by mass or more, and more preferably 1 part by mass or more.

[0240] With respect to 100 parts by mass of the refractory inorganic particles, the content of the clay mineral is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 2 parts by mass or less.

[0241] If the clay mineral is above the above lower limit in this ratio, an appropriate viscosity can be imparted to the dispersion liquid, and sedimentation and floating of the raw materials in the dispersion liquid can be prevented.

[0242] From the viewpoint of improving the thermal strength, the coating layer preferably further contains a second binder. From the viewpoints of improving the room temperature strength and heat resistance of the structure for casting manufacture, it is preferable to use a second binder when forming the coating layer.

[0243] As the second binder, one or more selected from organic binders and inorganic binders can be used, and it preferably contains an inorganic binder.

[0244] As the organic binder, for example, one or more selected from phenolic resin, epoxy resin, furan resin, water-soluble alkyd resin, water-soluble butyral resin, polyvinyl alcohol, water-soluble acrylic resin, water-soluble polysaccharide, vinyl acetate resin or its copolymer, etc. can be used.

[0245] As the inorganic binder, one or more selected from various sols such as sulfates, silicates, phosphates, lithium silicate, zirconia sol, colloidal silica, alumina sol, etc. can be used, preferably one or more selected from colloidal silica and aluminum phosphate, and more preferably contains colloidal silica.

[0246] With respect to 100 parts by mass of the second inorganic particles, in terms of active ingredient conversion, the second binder preferably contains 1 part by mass or more, and more preferably contains 3 parts by mass or more.

[0247] With respect to 100 parts by mass of the second inorganic particles, in terms of active ingredient conversion, the second binder preferably contains 50 parts by mass or less, more preferably contains 40 parts by mass or less, and further preferably contains 7 parts by mass or less.

[0248] Regarding a preferred embodiment of the manufacturing method of the structure for casting manufacturing of the present utility model, taking the manufacturing method of the structure 1 shown Figure 18 as an example for explanation.

[0249] Typically, the manufacturing method of the present embodiment has a main body part coating process for forming the inner surface covering layer 31 of the main body part, and a mold fitting part coating process for forming the outer surface covering layer 32 of the mold fitting part.

[0250] In the mold fitting part coating process of the present embodiment, in addition to the outer surface covering layer 32 of the mold fitting part, an inner surface covering layer 33 of the mold fitting part and an end surface covering part 34 of the mold fitting part are also formed.

[0251] In the main body part coating process, it is preferred to coat a coating liquid on the inner surface of the main body part 11 of the main body 20 to form the inner surface covering layer 31 of the main body part. Specifically, it is preferred to inject a coating liquid composition 70 into the main body part 11 and fill the main body part 11 with the coating liquid composition 70 (refer to Figure 18 (a) and (b)).

[0252] Specifically, a cover body 60 is arranged at the open end of the male mold fitting part 13. And the coating liquid composition 70 is filled into the main body part 11. When the upper surface of the coating liquid composition 70 reaches a desired height, the filling of the coating liquid composition 70 is ended. After a certain period of time, the cover body 60 is opened. Then, the coating liquid composition 70 is discharged, leaving the residual liquid adhering to the inner surface of the main body part 11.

[0253] It is preferred to leave the main body part 11 with the coating liquid composition 70 remaining therein in a state where the axial direction Z of the main body part 11 is substantially parallel to the vertical direction Z1, so that the coating liquid composition 70 remaining on the inner surface of the main body part 11 dries and cures, and the inner surface covering layer 31 of the main body part is formed on the inner surface of the main body part 11 (refer to Figure 18 (c)).

[0254] The mold fitting part coating process is preferably carried out after the main body part coating process. In the mold fitting part coating process, it is preferred to coat the coating liquid composition over the entire circumference of the inner surface, outer surface, and end surface of the mold fitting part 12 in the main body 20.

[0255] Specifically, it is preferred to immerse the mold fitting part 12 in the main body 20 in the coating liquid composition 71. And the coating liquid composition 71 is fused on the inner surface, outer surface, and end surface of the mold fitting part 12 (refer to Figure 18(d)). Then, after a certain period of time, the master mold fitting portion 12 is taken out from the coating liquid composition 71. By drying and curing the coating film, that is, the coating liquid composition 71 remaining on the inner surface, outer surface, and end surface of the master mold fitting portion 12, the inner surface covering layer 33 of the master mold fitting portion, the outer surface covering layer 32 of the master mold fitting portion, and the end surface covering portion 34 of the master mold fitting portion are formed.

[0256] In this way, the structure 1 having the inner surface covering layer 31 of the main body portion, the inner surface covering layer 33 of the master mold fitting portion, the outer surface covering layer 32 of the master mold fitting portion, and the end surface covering portion 34 of the master mold fitting portion is manufactured.

[0257] According to the manufacturing method of the present embodiment, the structure 1 can be efficiently manufactured.

[0258] In the main body portion coating step, the coating liquid composition 70 filled in the main body portion 11 may reach the upper surface 12e of the stepped portion 15 (refer to Figure 18 (b)), or may not reach (refer to Figure 19 (a)). In addition, the coating liquid composition 70 filled in the main body portion 11 may also reach the master mold fitting portion 12 (refer to Figure 19 (b) and (c)). When the coating liquid composition 70 reaches the master mold fitting portion 12, the coating liquid composition 70 may reach the open end of the master mold fitting portion 12 (refer to Figure 19 (b)), or may not reach (refer to Figure 19 (c)).

[0259] In the main body portion coating step, instead of filling the coating liquid composition 70 in the main body portion 11, for example, the coating liquid composition 70 may be applied to the inner surface of the main body portion 11 by using a brush or the like, thereby applying the coating liquid composition 70 to the inner surface of the main body portion 11.

[0260] From the viewpoint of being able to easily form the inner surface covering layer 31 of the main body portion and being able to manufacture the structure 1 more efficiently, it is preferable to apply the coating liquid composition 70 by filling the coating liquid composition 70 in the main body portion 11.

[0261] In the master mold fitting portion coating step, it may be immersed in the coating liquid composition 71 up to the position of the lower surface 15a of the stepped portion 15 in the main body portion 20 (refer to Figure 18 (d)), or only the portion of the master mold fitting portion 12 on the one - end 1a side closer than the lower surface 15a of the stepped portion 15 may be immersed in the coating liquid composition 71 (refer to Figure 19 (d)), or it may be immersed in the coating liquid composition 71 up to the position on the other - end 1b side closer than the lower surface 15a of the stepped portion 15 in the main body portion 20 (refer to Figure 19 (e)).

[0262] In the step of coating the female mold fitting portion of the present embodiment, an inner surface covering layer 33, an outer surface covering layer 32, and an end surface covering portion 34 of the female mold fitting portion are formed. However, in the step of coating the female mold fitting portion, only the outer surface covering layer 32 of the female mold fitting portion may be formed. For example, the coating liquid composition 71 may be applied to the outer surface of the female mold fitting portion 12 by applying the coating liquid composition 71 with a brush or the like.

[0263] From the viewpoint of being able to easily form the inner surface covering layer 33, the outer surface covering layer 32, and the end surface covering portion 34 of the female mold fitting portion and being able to manufacture the structure 1 more efficiently, it is more preferable to apply the coating liquid composition 71 by immersing the female mold fitting portion 12 in the main body portion 20 in the coating liquid composition 71 (refer to Figure 18 (d)).

[0264] The order of performing the step of coating the female mold fitting portion and the step of coating the main body portion is not particularly limited. For example, the step of coating the main body portion may be performed after the step of coating the female mold fitting portion, or the step of coating the female mold fitting portion and the step of coating the main body portion may be performed simultaneously.

[0265] In addition, the coating liquid composition 70 in the step of coating the main body portion and the coating liquid composition 71 in the step of coating the female mold fitting portion may be the same or different.

[0266] The main body portion 20 can be manufactured, for example, by the following method.

[0267] <Manufacturing method of the main body portion 20>

[0268] The main body portion 20 can be manufactured by a forming method having a papermaking process. Such a forming method is described, for example, in paragraphs

[0052] to

[0071] of Japanese Unexamined Patent Application Publication No. 2012-024841.

[0269] Specifically, first, a raw material slurry containing organic fibers, inorganic fibers, first inorganic particles, and a first binder in a predetermined ratio is prepared. The raw material slurry is prepared by dispersing organic fibers, inorganic fibers, first inorganic particles, and a first binder in a predetermined dispersion medium. In addition, the first binder may not be mixed in the raw material slurry but may be impregnated into the main body portion 20.

[0270] As the dispersion medium, in addition to water, one or more solvents selected from solvents such as ethanol, methanol, dichloromethane, acetone, and xylene can be used. Among them, from the viewpoint of ease of operation, it is preferable to contain water.

[0271] The content ratios of the organic fibers, inorganic fibers, first inorganic particles, and the first binder in the raw material slurry are appropriately adjusted so as to achieve the composition of the target main body portion 20.

[0272] In the raw material slurry, additives such as paper strength intensifiers, flocculants, and preservatives can be added as needed.

[0273] Next, using the raw material slurry, an intermediate formed body of the main body portion 20 is fabricated.

[0274] In the fabrication process of the above intermediate formed body, for example, a mold for fabrication and dehydration forming is used. This mold forms a cavity corresponding to the outer shape of the intermediate formed body inside by mating a pair of split molds. And a prescribed amount of the raw material slurry is pressure-injected into the cavity from the upper opening portion of the mold. Thus, the pressure in the cavity is increased to a prescribed pressure. A plurality of communication holes that communicate its exterior with the cavity are respectively provided in each split mold. In addition, the inner surfaces of the respective split molds are each covered with a net having a prescribed mesh size. The pressure injection of the raw material slurry uses, for example, a pressure feed pump. The pressure of the above pressure injection of the raw material slurry is preferably 0.01 MPa or more and 5 MPa or less, more preferably 0.01 MPa or more and 3 MPa or less, and still more preferably 0.1 MPa or more and 0.5 MPa or less.

[0275] As described above, since the pressure in the above cavity is increased, the dispersion medium in the raw material slurry is discharged from the above communication holes to the outside of the mold. On the other hand, the solid components in the above raw material slurry accumulate on the above net covering the cavity, and a fiber laminate is uniformly formed on the net. In the fiber laminate thus obtained, organic fibers and inorganic fibers are intricately intertwined, and there is an adhesive between them. Therefore, even for a complex shape, high shape retention can be obtained after drying and forming. In addition, since the pressure in the above cavity is increased, even when forming a hollow intermediate formed body, the raw material slurry flows in the cavity and the raw material slurry is agitated. Therefore, the slurry concentration in the cavity is homogenized, and the fiber laminate is uniformly deposited on the above net.

[0276] After forming the fiber laminate, the pressure injection of the above raw material slurry is stopped, air is pressed into the cavity, and the fiber laminate is pressurized and dehydrated. Then, the pressing of the air is stopped, and the cavity is suctioned through the above communication holes, and a mold core (elastic mold core) that is elastic, freely expandable and contractible, and hollow is inserted into the cavity. The mold core is preferably formed of polyurethane, fluorine-based rubber, silicone-based rubber, or an elastomer having excellent tensile strength, resilience, and stretchability, etc.

[0277] Next, a pressurized fluid is supplied into the above elastic mold core inserted into the cavity to expand the elastic mold core, and the fiber laminate is pressed against the inner surface of the cavity by the expanded elastic mold core. Thus, the fiber laminate is pressed against the inner surface of the cavity, the inner surface shape of the cavity is transferred to the outer surface of the fiber laminate, and dehydration of the fiber laminate is performed.

[0278] The pressurized fluid used to expand the above elastic die core is, for example, compressed air (heated air), oil (heated oil), or various other liquids. In addition, considering the manufacturing efficiency of the formed body, the supply pressure of the pressurized fluid is preferably 0.01 MPa or more and 5 MPa or less, more preferably 0.1 MPa or more and 3 MPa or less, and further preferably 0.1 MPa or more and 0.5 MPa or less from the viewpoint of manufacturing efficiently. If it is 0.01 MPa or more, the drying efficiency of the fiber laminate is good, and the surface property and transferability are also sufficient. If it is 5 MPa or less, good effects can be obtained and the device can be miniaturized.

[0279] In this way, since the above fiber laminate is pressed from its inside against the inner surface of the mold cavity, even if the shape of the inner surface of the mold cavity is complex, the inner surface shape can be transferred to the outer surface of the above fiber laminate with high precision. In addition, even if the formed body to be manufactured has a complex shape, there is no need for a fitting process for each part, so there are no seams and thick wall parts formed by fitting in the finally obtained component. That is, the finally obtained main body portion 20 has a structure integrally formed in the circumferential direction of the main body portion 20.

[0280] When the inner surface shape of the above mold cavity is sufficiently transferred to the outer surface of the above fiber laminate and the fiber laminate can be dehydrated to a specified moisture content, the pressurized fluid in the above elastic die core is removed, and the elastic die core automatically shrinks to its original size. Then, the shrunk elastic die core is taken out from the mold cavity, and further, the above mold is opened, and the fiber laminate in a wet state with a specified moisture content is taken out. It is also possible to omit the pressing and dehydration of the fiber laminate using the elastic die core, and only perform pressurization and dehydration based on the air pressure introduced into the mold cavity to dehydrate and form the fiber laminate.

[0281] The above fiber laminate after dehydration forming is then transferred to the heating and drying process.

[0282] In the heating and drying process, a drying and forming mold having a mold cavity formed with a shape corresponding to the outer shape of the above intermediate formed body is used. The mold is heated to a specified temperature, and the dehydrated and formed wet above fiber laminate is loaded into the mold.

[0283] Next, an elastic die core identical to the above-described elastic die core used in the above papermaking process is inserted into the above fiber laminate, and a pressurized fluid is supplied into the elastic die core to expand the elastic die core, and the above fiber laminate is pressed against the inner surface of the above die cavity by the expanded elastic die core. It is preferable to use an elastic die core surface-modified with a fluororesin, a silicone resin, or the like. The supply pressure of the pressurized fluid is preferably set to the same pressure as in the above dehydration process. In this state, the fiber laminate is heated and dried to dry-form the above intermediate formed body.

[0284] From the viewpoints of improving surface properties and shortening the drying time, the heating temperature (die temperature) of the above die for dry forming is preferably 100°C or higher and 300°C or lower, more preferably 150°C or higher and 250°C or lower, and further preferably 190°C or higher and 240°C or lower. The heat treatment time varies depending on the heating temperature and thus cannot be generalized, but from the viewpoints of improving quality and productivity, etc., it is preferably 0.5 minutes or longer and 30 minutes or shorter, more preferably 1 minute or longer and 10 minutes or shorter. If the heating temperature is 300°C or lower, the surface properties of the intermediate formed body are good, and if it is 100°C or higher, the drying time of the intermediate formed body can also be shortened.

[0285] After the above fiber laminate is sufficiently dried, the above pressurized fluid in the elastic die core is removed, the die core is contracted, and it is taken out from the fiber laminate. Then, the above die is opened, and the above intermediate formed body is taken out. The thermosetting resin of the intermediate formed body is cured by heat treatment and used as the main body portion 20.

[0286] The main body portion 20 thus obtained is pressed by the elastic die core, so the smoothness of the inner surface and the outer surface is high. Therefore, the forming accuracy is also high, and a highly accurate structure can be obtained even in the case of having a fitting portion and a threaded portion. Therefore, the molten metal flows smoothly in the structure connected by these fitting portions and threaded portions. In addition, the thermal shrinkage rate of the main body portion 20 during casting is also less than 5%, so it is possible to prevent leakage of the molten metal caused by cracks, deformation, etc. of the structure without problems.

[0287] It is possible to further impregnate the obtained intermediate formed body partially or entirely with the first adhesive. On the other hand, in the case where the first adhesive is impregnated into the intermediate formed body and not included in the raw material slurry, the treatment of the raw material slurry and white water becomes simple. In the case of using a thermosetting adhesive as the first adhesive, the intermediate formed body is heated and dried at a specified temperature to thermally cure the thermosetting adhesive to complete the manufacture of the main body portion 20.

[0288] As described above, the present utility model has been described based on preferred embodiments and implementation forms, but the present utility model is not limited to the above-described embodiments and implementation forms. The above-described embodiments and their modified examples can be combined within the scope where their contents do not conflict with each other. For example, the structure for casting manufacturing of the present utility model may also have both the outer surface covering layer 32 of the female mold fitting portion 12 and the outer surface covering layer 36 of the male mold fitting portion 13.

[0289] Hereinafter, the present utility model will be further described in detail based on examples, but the present utility model is not limited to the following examples.

[0290] [Example 1]

[0291] Manufacture by the above manufacturing method Figure 9 The shown structure 1 is used as the structure for casting manufacturing in Example 1. The constitution of the structure for casting manufacturing in Example 1 is as shown in Table 1 and as follows. Specifically, with respect to 100 parts by mass of zircon, 1.25 parts by mass of attapulgite and 5 parts by mass of colloidal silica are mixed. For the main body part, with the total of all components set to 100 parts by mass, 10.2 parts by mass of waste newspaper, 8.5 parts by mass of carbon fiber, 66 parts by mass of spherical silica, and 15.3 parts by mass of phenolic resin are mixed.

[0292] Zircon: Manufactured by Hakusui Tech Co., Ltd., Zirconia No. 1

[0293] Attapulgite: Manufactured by Hayashi Kasei Co., Ltd., ATTAGEL50

[0294] Colloidal silica: Manufactured by Nissan Chemical Industries, Ltd., SNOWTEX50

[0295] Carbon fiber: Manufactured by Toray Industries, Inc., Torayca chopped fiber

[0296] Spherical silica: Manufactured by Micron, Inc., S85-P

[0297] Phenolic resin: Manufactured by AIR WATER PERFORMANCE CHEMICAL INC., Bellpearl S890

[0298] The inner diameter of the male mold fitting portion is 99.4 mm, and the outer diameter is 102.4 mm. The thickness T2 of the inner surface covering layer of the female mold fitting portion is 0.1 mm, the thickness T3 of the inner surface covering layer of the main body portion is 0.3 mm, and the thickness T1 of the overlapping portion of the inner surface covering layer of the female mold fitting portion and the inner surface covering layer of the main body portion is 0.4 mm.

[0299] [Example 2]

[0300] Manufacture by the above manufacturing methodFigure 1 The shown structure 1 is used as the structure for manufacturing a casting in Example 2. In addition, in the step of coating the female mold fitting portion, the coating liquid composition 70 is applied to the outer surface of the female mold fitting portion 12 by using a brush or the like, and thus the coating liquid composition 70 is applied to the outer surface of the female mold fitting portion 12. The composition of the structure for manufacturing a casting in Example 2 is the same as that of the structure for manufacturing a casting in Example 1.

[0301] [Comparative Example 1]

[0302] A structure for manufacturing a casting is manufactured in the same manner as in Example 1 except that the step of coating the female mold fitting portion is not performed.

[0303] [Table 1]

[0304]

[0305] [Evaluation of whether molten metal leaks out during pouring]

[0306] For each structure for manufacturing a casting in Example 1 and Comparative Example 1, a cylindrical body is manufactured by connecting the structure for manufacturing a casting. Then, molten metal is poured into a sand mold, i.e., a mold, having each cylindrical body as a runner tube to manufacture a casting. The molten metal used is 5t carbon steel casting SC450 (JIS classification). Visual observation of the surface of each remaining cylindrical body after solidification of the molten metal and observation of the cut surface of the fitting portion are performed. The case where the molten metal does not leak out from the cylindrical body and the metal inside the sand mold and the cylindrical body can be separated is evaluated as "no leakage". In addition, the case where the molten metal leaks out from the cylindrical body and a part of the molding sand of the sand mold is sintered is evaluated as "leakage".

[0307] As shown in Table 1, in Comparative Example 1, leakage of molten metal occurred. In contrast, in Example 1, leakage of molten metal did not occur. Therefore, it can be known that according to the structure for manufacturing a casting of the present utility model, sintering caused by leakage from the fitting portion can be suppressed.

[0308] Industrial applicability

[0309] According to the structure for manufacturing a casting of the present utility model, leakage of molten metal during pouring can be prevented.

[0310] According to the manufacturing method of the structure for manufacturing a casting of the present utility model, a structure for manufacturing a casting that can prevent leakage of molten metal during pouring can be efficiently manufactured.

Claims

1. A structure for manufacturing a cylindrical casting, characterized in that: It has a cylindrical main body portion, and the main body portion has: a main trunk portion; and a master mold fitting portion that is continuously provided with the main trunk portion and has an inner diameter greater than or equal to the outer diameter of the main trunk portion. And it has an inner surface covering layer of the main trunk portion that covers the inner surface of the main trunk portion and an outer surface covering layer that covers the outer surface of the master mold fitting portion.

2. The structure for manufacturing a casting according to claim 1, characterized in that: The outer surface covering layer covers the entire area of the outer surface of the master mold fitting portion.

3. The structure for manufacturing a casting according to claim 1, characterized in that: It has an inner surface covering layer of the master mold fitting portion that covers the inner surface of the master mold fitting portion.

4. The structure for manufacturing a casting according to claim 3, characterized in that: The inner surface covering layer of the master mold fitting portion is continuous with the inner surface covering layer of the main trunk portion.

5. The structure for manufacturing a casting according to claim 3, characterized in that: The inner surface covering layer of the master mold fitting portion extends to the inner surface of the main trunk portion, and a part of it overlaps with the inner surface covering layer of the main trunk portion.

6. The structure for manufacturing a casting according to claim 5, characterized in that: In the overlapping part of the inner surface covering layer of the master mold fitting portion and the inner surface covering layer of the main trunk portion, the inner surface covering layer of the master mold fitting portion is arranged at a position radially inward of the inner surface covering layer of the main trunk portion with respect to the casting manufacturing structure.

7. The structure for manufacturing a casting according to claim 5, characterized in that: The thickness of the overlapping part of the inner surface covering layer of the master mold fitting portion and the inner surface covering layer of the main trunk portion is greater than either the thickness of the thickest part of the inner surface covering layer of the master mold fitting portion or the thickness of the thickest part of the inner surface covering layer of the main trunk portion.

8. The structure for manufacturing a casting according to claim 3, characterized in that: The inner surface covering layer of the master mold fitting portion covers the entire area of the inner surface of the master mold fitting portion. The inner surface covering layer of the main trunk portion covers the entire area of the inner surface of the main trunk portion.

9. The structure for manufacturing a casting according to claim 3, characterized in that: The positions of the end edges of the inner surface covering layer of the master mold fitting portion and the outer surface covering layer on the proximal end side in the continuous setting direction of the master mold fitting portion are the same.

10. The structure for manufacturing a casting according to claim 1, characterized in that: It has an end face covering portion that covers the end face of the master mold fitting portion.

11. The structure for manufacturing a casting according to claim 10, characterized in that: It has an outer surface covering layer of the master mold fitting portion that covers the outer surface of the master mold fitting portion. The outer surface covering layer of the master mold fitting portion is continuous with the end face covering portion.

12. The structure for manufacturing a casting according to claim 1, characterized in that: It has an inner surface covering layer of the master mold fitting portion that covers the inner surface of the master mold fitting portion; and an end face covering portion that covers the end face of the master mold fitting portion, and the end face covering portion is continuous with the inner surface covering layer of the master mold fitting portion.

13. The structure for casting manufacture according to claim 1, characterized in that: The outer surface covering layer extends to the inner surface of the main body part through the end face of the master mold fitting part.

14. The structure for casting manufacture according to claim 1, characterized in that: It has a master mold fitting part inner surface covering layer covering the inner surface of the master mold fitting part, and the thickness of the master mold fitting part inner surface covering layer is less than the thickness of the covering layer other than the master mold fitting part inner surface covering layer.

15. The structure for casting manufacture according to claim 1, characterized in that: The outer diameter of the end part of the structure for casting manufacture other than the master mold fitting part is less than or equal to the inner diameter of the master mold fitting part.

16. The structure for casting manufacture according to claim 15, characterized in that: Among the outer diameters of the structure for casting manufacture, the outer diameter of the master mold fitting part is the largest, and among the inner diameters of the structure for casting manufacture, the inner diameter of the master mold fitting part is the largest.

17. The structure for casting manufacture according to claim 1, characterized in that: The inner diameter of the end part of the structure for casting manufacture other than the master mold fitting part is 100 mm or more.

18. A cylindrical structure for casting manufacture, characterized in that: It has a cylindrical main body part, and at one end part of the main body part, there is a male mold fitting part that fits into the master mold fitting part, the outer diameter of the male mold fitting part is less than or equal to the inner diameter of the master mold fitting part, and it has a main body part inner surface covering layer covering the inner surface of the main body part and an outer surface covering layer covering the outer surface of the male mold fitting part.

19. The structure for casting manufacture according to claim 18, characterized in that: It has an end face covering part covering the end face of the male mold fitting part.

20. The structure for casting manufacture according to claim 19, characterized in that: The end face covering part is continuous with the outer surface covering layer.

21. The structure for casting manufacture according to claim 18, characterized in that: The main body part has a master mold fitting part that is continuously provided with the main body part and has an inner diameter greater than or equal to the outer diameter of the main body part, and the outer diameter of the male mold fitting part is less than or equal to the inner diameter of the master mold fitting part that is continuously provided with the main body part.

22. The structure for casting manufacture according to claim 1 or 18, characterized in that: The main body part has a single-layer structure.

23. The structure for casting manufacture according to claim 1 or 18, characterized in that: The main body part is integrally formed in the circumferential direction of the main body part.

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