Method for manufacturing a hose and mandrel

Abstract

To provide a method for manufacturing a hose that facilitates further reliably removing a mandrel from a hose after vulcanization to enhance productivity of the hose, and the mandrel used in the manufacturing method.SOLUTION: In a vulcanization step for vulcanizing a hose molding 4A molded on an outer peripheral surface 2a of a mandrel 1 with use of a vulcanization device 10, after the hose molding 4A becomes a predetermined vulcanization state, at least an outermost resin layer 2 of the mandrel 1 is made into a molten state, and a molten resin is removed from an inside of a hose 4 with use of a removal device 11. Thereafter, an unmolten core portion 3 of the mandrel 1 is removed from the inside of the hose 4.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a hose and a mandrel, and more particularly, to a method for manufacturing a hose that can more reliably remove the mandrel from the hose after vulcanization and improve the productivity of the hose, and a mandrel used in this manufacturing method.

Background Art

[0002] When manufacturing a hose, a rod-shaped mandrel is used. Hose components are sequentially laminated on the outer peripheral surface of the mandrel to form a hose preform, and then the hose is manufactured by vulcanizing the hose preform. The mandrel is pulled out from the hose after vulcanization.

[0003] Since the inner peripheral surface of the hose after vulcanization adheres to the outer peripheral surface of the mandrel, there may be a problem that it becomes difficult to pull out the mandrel from the hose. To prevent this problem, various measures have been proposed to appropriately set the roughness of the outer peripheral surface of the mandrel (for example, Patent Document 1). However, due to differences in hose specifications, the appropriate surface roughness of the outer peripheral surface that makes the mandrel easier to pull out is different, so the mandrel may not be smoothly pulled out. In addition, for each hose specification, it is necessary to grasp the appropriate surface roughness of the outer peripheral surface of the mandrel to be used and prepare a mandrel with this appropriate surface roughness. Therefore, there is room for improvement in more reliably removing the mandrel from the hose after vulcanization and improving the productivity of the hose.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a method for manufacturing a hose that can improve the productivity of hoses by making it easier to remove the mandrel more reliably from the hose after vulcanization, and a mandrel used in this manufacturing method. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a method for manufacturing a hose, in which a hose molded body formed on the outer surface of a mandrel is vulcanized to produce a hose, wherein in the vulcanization step of the hose molded body, after the hose molded body reaches a predetermined vulcanized state, the mandrel Outermost perimeter The resin layer is melted, The outermost resin layer has a thickness of 1 mm or more. The molten resin is removed from the inside of the vulcanized hose, then the unmolten mandrel portion is pulled out from the inside of the hose to manufacture the hose, and the unmolten mandrel portion is regenerated as a mandrel by laminating resin onto its outer surface. It is characterized by the following: Another method for manufacturing a hose according to the present invention is a method for manufacturing a hose by vulcanizing a hose molded body formed on the outer surface of a mandrel, characterized in that a resin mandrel is used as the mandrel, and in the vulcanization process of the hose molded body, after the hose molded body has reached a predetermined vulcanized state, the core of the mandrel is melted, the molten resin is removed from the inside of the vulcanized hose, and then the unmelted portion of the mandrel is pulled out from the inside of the hose to manufacture the hose. A further method for manufacturing a hose according to the present invention is a method for manufacturing a hose by vulcanizing a hose molded body formed on the outer surface of a mandrel, characterized in that a resin mandrel is used as the mandrel, and after the hose molded body reaches a predetermined vulcanized state in the vulcanization step of the hose molded body, the entire mandrel is melted, and the molten resin is removed from the inside of the vulcanized hose to manufacture the hose.

[0007] The mandrel of the present invention is a mandrel that is placed inside a vulcanizing apparatus together with a hose molded body formed on its outer surface, and in the vulcanization process of the hose molded body using the vulcanizing apparatus, after the hose molded body has reached a predetermined vulcanized state, it is in a molten state. Outermost perimeter It has a resin layer Furthermore, the outermost resin layer has a thickness of 1 mm or more, and the molten resin is removed, and resin is laminated onto the outer surface of the remaining portion to regenerate it. It is characterized by the following: Another mandrel of the present invention is a mandrel that is placed inside a vulcanizing apparatus together with a hose molded on its outer surface, and is characterized in that the entire mandrel is made of resin, and has a core that is molten after the hose molded has reached a predetermined vulcanized state in the vulcanization process of the hose molded using the vulcanizing apparatus, and the molten resin is removed and the remaining portion is filled with resin to regenerate it. A further mandrel of the present invention is a mandrel that is placed inside a vulcanizing apparatus together with a hose molded on its outer surface, characterized in that the entire mandrel is made of resin, and the entire mandrel is melted after the hose molded has reached a predetermined vulcanized state during the vulcanization process of the hose molded using the vulcanizing apparatus. [Effects of the Invention]

[0008] According to the present invention, in the vulcanization process of the hose molded body, after the hose molded body reaches a predetermined vulcanized state, at least the outermost resin layer of the mandrel is melted, or, if a resin mandrel is used as the mandrel, at least its core is melted. Since the mandrel in this state can be removed more reliably from the hose after vulcanization, it is advantageous for improving the productivity of the hose. [Brief explanation of the drawing]

[0009] [Figure 1]It is a side view schematically illustrating the mandrel of the present invention and a hose molded body with a partial notch. [Figure 2] It is an explanatory view illustrating the mandrel and the hose molded body of FIG. 1 in a cross-sectional view. [Figure 3] It is a side view schematically illustrating a hose produced by vulcanizing the hose molded body of FIG. 1, with a part cut away. [Figure 4] It is an explanatory view illustrating the vulcanization process of the hose molded body of FIG. 1. [Figure 5] It is an explanatory view illustrating the process of melting and removing the resin layer on the outermost periphery of the mandrel of FIG. 4. [Figure 6] It is an explanatory view illustrating the process of removing the core part of the mandrel from the inside of the hose obtained by vulcanizing the hose molded body of FIG. 5. [Figure 7] It is a side view schematically illustrating the mandrel of another embodiment and a hose molded body with a partial notch. [Figure 8] It is an explanatory view illustrating the mandrel and the hose molded body of FIG. 7 in a cross-sectional view. [Figure 9] It is an explanatory view illustrating the vulcanization process of the hose molded body of FIG. 7. [Figure 10] It is an explanatory view illustrating the process of melting and removing the core part of the mandrel of FIG. 9. [Figure 11] It is an explanatory view illustrating the process of removing the outer peripheral layer of the mandrel from the inside of the hose obtained by vulcanizing the hose molded body of FIG. 10. [Figure 12] It is a side view schematically illustrating the mandrel of another embodiment and a hose molded body with a partial notch. [Figure 13] It is an explanatory view illustrating the mandrel and the hose molded body of FIG. 12 in a cross-sectional view. [Figure 14] It is an explanatory view illustrating the vulcanization process of the hose molded body of FIG. 12. [Figure 15] It is an explanatory view illustrating the process of melting the entire mandrel of FIG. 14 and removing it from the hose.

Mode for Carrying Out the Invention

[0010] Hereinafter, the method for manufacturing the hose of the present invention and the mandrel will be described based on the embodiments shown in the drawings.

[0011] In the method for manufacturing the hose of the present invention, the hose 4 illustrated in FIG. 3 is manufactured by vulcanizing the hose molded body 4A formed on the outer peripheral surface of the mandrel 1 of the present invention illustrated in FIGS. 1 to 2. In the figure, the dashed-dotted line CL indicates the hose axis passing through the center of the cross section of the hose 4 (hose molded body 4A). This hose 4 has a reinforcing layer 6 and an intermediate rubber layer 7 interposed between the inner surface layer 5 located on the innermost peripheral side and the outer surface layer 8 located on the outermost peripheral side, and the cylindrical inner surface layer 5, reinforcing layer 6, intermediate rubber layer 7, and outer surface layer 8 are laminated coaxially. The inner peripheral side of the inner surface layer 5 forms the flow path of the hose 4, and the inner peripheral surface 5a comes into contact with the fluid flowing through the flow path.

[0012] The inner surface layer 5 is formed of various rubbers such as NBR-based rubber, SBR rubber, and ENR rubber, and may also be formed of various resins such as 6 nylon, polyolefin-based resin, and fluororesin. The material (type of rubber or resin) and layer thickness for forming the inner surface layer 5 are appropriately determined according to the required performance of the hose 4.

[0013] The reinforcing layer 6 is formed by reinforcing cords 6a. As the reinforcing cords 6a, non-metallic fibers such as polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, aramid fiber, polyparaphenylene benzoxazole (PBO) fiber, 66 nylon fiber, rayon fiber, vinylon fiber, and cotton fiber are used alone or in combination of multiple types. As the reinforcing cords 6a, metal wires such as wires may also be used.

[0014] The reinforcing layer 6 illustrated in Figure 3 has a braided structure in which the reinforcing cord 6a is braided at a predetermined angle with respect to the hose axis CL. The reinforcing layer 6 is not limited to a braided structure; it may also be a spiral structure formed by winding the reinforcing cord 6a spirally at a predetermined angle with respect to the hose axis CL. This hose 4 has two layers of reinforcing layer 6, but the reinforcing layer 6 may be a single layer or have three or more layers. The specifications of the reinforcing cord 6a (material, wire diameter, etc.) and the number of layers of the reinforcing layer 6 are appropriately determined according to the required performance of the hose 4.

[0015] The intermediate rubber layer 7 firmly joins the adjacent laminated reinforcing layers 6 together and functions as a buffer to prevent the reinforcing cords 6a forming each reinforcing layer 6 from contacting each other and causing wear. The intermediate rubber layer 7 can be of a known specification used in hose manufacturing. The intermediate rubber layer 7 is not an essential component and may be omitted.

[0016] The outer layer 8 is formed from various types of rubber or resin, such as CR rubber, EPDM rubber, or SBR rubber. The material (type of rubber or resin) and thickness of the outer layer 8 are determined appropriately according to the required performance for the hose 4.

[0017] The rod-shaped mandrel 1 is used as a core material when manufacturing the hose 4. The mandrel 1 can be made entirely of resin, or partially (core 3) made of metal. In either case, the outermost layer 2 of the mandrel 1 is made of resin. Examples of resins that can form the mandrel 1 include polymethylpentene, nylon 6, nylon 11, nylon 12, polypropylene, and polyester. Examples of metals that can form part of the mandrel 1 (core 3) include iron, stainless steel, and aluminum. Making the entire mandrel 1 out of resin is advantageous for improving handling (workability) because it reduces weight and bending rigidity.

[0018] The outer diameter and length of mandrel 1 are not particularly limited as they vary depending on the specifications of the hose 4 being manufactured, but the outer diameter is, for example, 3mm to 50mm. The length of mandrel 1 is, for example, 20m to 200m, and it is easier to make it longer if the entire mandrel 1 is made of resin.

[0019] The mandrel 1 in this embodiment has a cylindrical core 3 and a cylindrical outer layer 2 that covers the outer surface of the core 3. The portion other than the core 3 becomes the outer layer 2. The core 3 is not limited to a cylindrical shape but can also be cylindrical. The thickness of the outer layer 2 is, for example, 1 mm or more. There is no particular upper limit to the thickness of the outer layer 2, but it is, for example, 5 mm or less.

[0020] The core 3 is made of resin or metal, and the outer layer 2 is made of resin. The melting temperature A2 of the outer layer 2 is lower than the melting temperature A3 of the core 3. In other words, this mandrel 1 is designed so that the outer layer 2 melts more easily than the core 3. Furthermore, the melting temperature A2 of the outer layer 2 is less than or equal to the highest vulcanization temperature T2 in the vulcanization process of the hose molded body 4A, while the melting temperature A3 of the core 3 is higher than the vulcanization temperature T2.

[0021] The following describes an example of the procedure for manufacturing hose 4 using mandrel 1.

[0022] When manufacturing the hose 4, as illustrated in Figures 1 and 2, a rod-shaped mandrel 1 is used as the core material, and the components constituting the inner layer 5, reinforcing layer 6, intermediate rubber layer 7, reinforcing layer 6, and outer layer 8 are sequentially laminated on the outer circumference of the mandrel 1 by a known method, thereby forming a hose molded body 4A on the outer circumference 2a of the mandrel 1. The innermost circumference (inner surface 5a) of the hose molded body 4A is in contact with the outermost circumference (outer surface 2a) of the mandrel 1.

[0023] Next, when vulcanizing the hose molded body 4A, a covering material 9, which functions as an outer mold, is laminated onto the outermost surface of the hose molded body 4A, so that the hose molded body 4A is covered with the covering material 9 along its entire length. The covering material 9 can be any known material used in hose manufacturing, and can be made of polymethylpentene or nylon 11, for example.

[0024] Next, as illustrated in Figure 4, the hose molded body 4A covered with the covering material 9 is placed inside the vulcanizing apparatus 10 together with the mandrel 1. As the vulcanizing apparatus 10, any known type used in hose manufacturing, such as a vulcanizing box, may be used.

[0025] A molten resin removal device 11 is attached to the hose molded body 4A. The removal device 11 has a suction means 11a such as a suction pump, a head portion 11b attached to one longitudinal end of the hose molded body 4A, and a lid portion 11d attached to both longitudinal ends of the hose molded body 4A. The inside of the hose molded body 4A is sealed by the attached head portion 11b and lid portion 11d. The head portion 11b is connected to the suction means 11a through piping. A through passage 11c communicating with the suction means 11a is formed in the head portion 11b, and the end of this through passage 11c is set at the position of the outer peripheral layer 2.

[0026] The hose molded body 4A is heated to a predetermined temperature under a predetermined pressure or normal pressure inside the vulcanizing apparatus 10, thereby vulcanizing the unvulcanized rubber that constitutes the hose molded body 4A. In the vulcanization process of the hose molded body 4A, after the hose molded body 4A has reached a predetermined vulcanized state, at least the outermost resin layer of the mandrel 1 (i.e., the outer layer 2) is melted. In this embodiment, after the hose molded body 4A has reached a predetermined vulcanized state, only the outer layer 2 is melted.

[0027] More specifically, by vulcanizing the hose molded body 4A at a predetermined vulcanization temperature T1, the vulcanization reaction of the unvulcanized rubber of the hose molded body 4A is allowed to proceed to a certain extent, bringing the shape of the hose molded body 4A to a state where it has not substantially changed (a predetermined vulcanization state). The predetermined vulcanization time D1 required to bring the hose molded body 4A to this predetermined vulcanization state at vulcanization temperature T1 can be determined in advance through prior test vulcanization or simulation analysis.

[0028] Subsequently, the vulcanization temperature T1 is raised to T2, and the vulcanization process is continued for a predetermined vulcanization time D2 to completely vulcanize the hose molded body 4A and manufacture the hose 4. In other words, the necessary thermal history to be imparted to the hose molded body 4A in the vulcanization process to manufacture the hose 4 is imparted to the hose molded body 4A by the process of vulcanization temperature T1 × vulcanization time D1 and the process of vulcanization temperature T2 × vulcanization time D2.

[0029] The vulcanization temperatures T1 and T2 are generally in the range of 140°C to 200°C. The vulcanization temperature T2 should ideally be at least 10°C higher than the vulcanization temperature T1.

[0030] The vulcanization temperature T1 is set lower than the melting temperature A2 of the resin forming the outer layer 2. The vulcanization temperature T2 is set to be equal to or greater than the melting temperature A2 of the resin forming the outer layer 2, and lower than the melting temperature A3 of the material (resin or metal) forming the core 3. Therefore, when the vulcanization temperature is raised to T2, the outer layer 2 melts, but the core 3 does not.

[0031] As illustrated in Figure 5, when the resin forming the outer peripheral layer 2 is molten, the suction means 11a is operated to remove the molten resin from inside the hose 4. This reduces the outer diameter of the mandrel 1, and a gap is formed between the outer peripheral surface of the mandrel 1 (core 3) and the inner peripheral surface 5a of the hose 4. If the thickness of the outer peripheral layer 2 is too large, a large amount of molten resin will be removed from inside the hose 4, and if the thickness is too small, it will be difficult to form a gap between the outer peripheral surface of the mandrel 1 (core 3) and the inner peripheral surface 5a of the hose 4. Therefore, it is advisable to determine the appropriate thickness of the outer peripheral layer 2 through prior testing. Note that if a gap can be formed between the outer peripheral surface of the mandrel 1 and the inner peripheral surface 5a of the hose 4, it is not necessary to remove all of the resin forming the outer peripheral layer 2 from inside the hose 4.

[0032] Next, as illustrated in Figure 6, the unmelted portion of the mandrel 1 (i.e., the core 3) is pulled out from inside the hose 4. For example, by a known method, water pressure is applied to the inside of the hose 4 from one longitudinal end and the core 3 is pulled out from the other longitudinal end. The covering material 9 is removed from the hose 4 by a known method after the hose 4 has been manufactured.

[0033] In this embodiment, as described above, a mandrel 1 having at least a resin outer layer 2 that is molten after the hose molded body 4A has reached a predetermined vulcanization state is used. By removing the molten resin of the outer layer 2 from the inside of the hose 4, a gap is formed between the inner surface 5a of the vulcanized hose 4 and the outer surface of the mandrel 1, thereby reliably avoiding close contact between the two. As a result, it becomes easier to reliably remove the mandrel 1 from the vulcanized hose 4, and the time required for the process of removing the mandrel 1 can be shortened. Consequently, this is advantageous in improving the productivity of the hose 4.

[0034] The used core 3 can be recycled as a mandrel 1 by laminating resin again onto its outer surface to form an outer layer 2. The recycled mandrel 1 can then be used to manufacture a new hose 4.

[0035] Another embodiment of the mandrel 1 illustrated in Figures 7 and 8 has a cylindrical core 3 and a cylindrical outer layer 2 that covers the outer surface of the core 3. In this embodiment, since the entire mandrel 1 is made of resin, the outer layer 2 and the core 3 are made of resin. In this embodiment, the melting temperature A2 of the outer layer 2 is higher than the melting temperature A3 of the core 3. That is, this mandrel 1 is designed so that the core 3 melts more easily than the outer layer 2. Furthermore, the melting temperature A3 of the core 3 is less than or equal to the highest vulcanization temperature T2 in the vulcanization process of the hose molded body 4A, and the melting temperature A2 of the outer layer 2 is higher than the vulcanization temperature T2.

[0036] In this embodiment, the reinforcing layer 6 of the hose molded body 4A has a spiral structure formed by winding a reinforcing cord 6a spirally at a predetermined angle with respect to the hose axis CL. This reinforcing layer 6 may also have a blade structure, as in the previous embodiment.

[0037] To manufacture the hose 4 using this mandrel 1, a hose molded body 4A is formed on the outer surface 2a of the mandrel 1 by the same procedure as in the previous embodiment, as illustrated in Figures 7 and 8. Next, when vulcanizing the hose molded body 4A, the hose molded body 4A covered with the covering material 9 is placed inside the vulcanizing apparatus 10 together with the mandrel 1 by the same procedure as in the previous embodiment, as illustrated in Figure 9.

[0038] A head portion 11b is attached to one longitudinal end of the hose molded body 4A, and a cap portion 11d is attached to the longitudinal end of the hose molded body 4A. The inside of the hose molded body 4A is sealed by the attached head portion 11b and cap portion 11d. The end of the through passage 11c formed in the head portion 11b is set at the position of the core portion 3.

[0039] In the vulcanization process of the hose molded body 4A, at least the core portion 3 of the mandrel 1 is melted after the hose molded body 4A has reached a predetermined vulcanization state. In this embodiment, only the core portion 3 is melted after the hose molded body 4A has reached a predetermined vulcanization state.

[0040] More specifically, similar to the previous embodiment, the hose molded body 4A is vulcanized at a predetermined vulcanization temperature T1, allowing the vulcanization reaction of the unvulcanized rubber to progress to a certain extent, bringing the shape of the hose molded body 4A to a state where it has not substantially changed (a predetermined vulcanization state). Subsequently, the vulcanization temperature T1 is raised to T2, and the vulcanization process is continued for a predetermined vulcanization time D2, completely vulcanizing the hose molded body 4A to manufacture the hose 4.

[0041] The vulcanization temperature T1 is set lower than the melting temperature A3 of the resin forming the core 3. The vulcanization temperature T2 is set to be equal to or greater than the melting temperature A3 of the resin forming the core 3, and lower than the melting temperature A2 of the resin forming the outer layer 2. Therefore, when the vulcanization temperature is raised to T2, the core 3 melts, but the outer layer 2 does not.

[0042] As illustrated in Figure 10, when the resin forming the core 3 is molten, the molten resin is removed from inside the hose 4 by operating the suction means 11a. As a result, the resin mandrel 1 is substantially reduced in diameter, with only the outer layer 2 remaining, becoming cylindrical (hollow), and thus easily deformed to reduce in diameter. To facilitate the reduction in diameter of the remaining outer layer 2, it is preferable to make the thickness of the outer layer 2 3 mm or less. In addition, if the mandrel 1 can be reduced in diameter during the mandrel 1 drawing process described later, and a gap can be formed between the outer surface 2a of the mandrel 1 (outer layer 2) and the inner surface 5a of the hose 4, it is not necessary to remove all of the resin forming the core 3 from inside the hose 4.

[0043] Next, as illustrated in Figure 11, the unmelted portion of the mandrel 1 (i.e., the outer layer 2) is withdrawn from inside the hose 4. A known method can be used to withdraw the outer layer 2 from inside the hose 4.

[0044] In this embodiment, as described above, a mandrel 1 having at least a core portion 3 that is molten after the hose molded body 4A has reached a predetermined vulcanization state is used. Even if the outer surface 2a of the mandrel 1 (outer surface layer 2) and the inner surface 5a of the hose 4 are in close contact, bending the vulcanized hose 4 or pressing it from the outer surface toward the hose axis will cause the mandrel 1 to deform in diameter, making it easier to form a gap between them. Therefore, it becomes easier to remove the mandrel 1 from the vulcanized hose 4 more reliably, and the time required for the process of removing the mandrel 1 can be shortened. Accordingly, this is advantageous in improving the productivity of the hose 4.

[0045] The used outer layer 2 can be refilled with resin to form the core 3, thereby regenerating it as a mandrel 1. The regenerated mandrel 1 can then be used when manufacturing a new hose 4.

[0046] Another embodiment of the mandrel 1 illustrated in Figures 12 and 13 is a cylindrical mandrel 1 formed entirely from the same resin. That is, unlike the previous embodiments, the core portion 3 and the outer layer 2 are not distinguished. This mandrel 1 can also be cylindrical. The melting temperature A1 of this mandrel 1 is below the maximum vulcanization temperature T2 in the vulcanization process of the hose molded body 4A.

[0047] To manufacture the hose 4 using this mandrel 1, a hose molded body 4A is formed on the outer surface 2a of the mandrel 1 by the same procedure as in the previous embodiment, as illustrated in Figures 12 and 13. Next, when vulcanizing the hose molded body 4A, the hose molded body 4A covered with the covering material 9 is placed inside the vulcanizing apparatus 10 together with the mandrel 1 by the same procedure as in the previous embodiment, as illustrated in Figure 14.

[0048] A head portion 11b is attached to one longitudinal end of the hose molded body 4A, and a cap portion 11d is attached to the longitudinal end of the hose molded body 4A. The inside of the hose molded body 4A is sealed by the attached head portion 11b and cap portion 11d. The end of the through passage 11c formed in the head portion 11b is set at the position of the mandrel 1 (the inner circumference portion of the hose molded body 4A).

[0049] In the vulcanization process of the hose molded body 4A, after the hose molded body 4A has reached a predetermined vulcanized state, the entire mandrel 1 is brought into a molten state.

[0050] More specifically, similar to the previous embodiment, the hose molded body 4A is vulcanized at a predetermined vulcanization temperature T1, allowing the vulcanization reaction of the unvulcanized rubber to progress to a certain extent, bringing the shape of the hose molded body 4A to a state where it has not substantially changed (a predetermined vulcanization state). Subsequently, the vulcanization temperature T1 is raised to T2, and the vulcanization process is continued for a predetermined vulcanization time D2, completely vulcanizing the hose molded body 4A to manufacture the hose 4.

[0051] The vulcanization temperature T1 is set lower than the melting temperature A1 of the resin forming mandrel 1. The vulcanization temperature T2 is set higher than or equal to the melting temperature A1 of the resin forming mandrel 1. Therefore, when the vulcanization temperature is raised to T2, the entire mandrel 1 melts.

[0052] As illustrated in Figure 15, when the resin forming the mandrel 1 is molten, the suction means 11a is operated to remove the molten resin from inside the hose 4. This makes the inside of the vulcanized hose 4 hollow. It is desirable to remove all of the resin forming the mandrel 1 from inside the hose 4, but some may remain. If resin remains inside the hose 4, it can be removed by applying water pressure to the inside from one end in the longitudinal direction of the hose 4 using a known method, for example, and discharging it from the other end in the longitudinal direction.

[0053] In this embodiment, the mandrel 1 can be removed from the vulcanized hose 4 by removing the resin forming the mandrel 1 using the removal device 11, thus shortening the time required for the mandrel 1 removal process. This is advantageous for improving the productivity of the hose 4.

[0054] The resin removed from the inside of hose 4 can be reused and recycled as mandrel 1. The recycled mandrel 1 can then be used to manufacture a new hose 4.

[0055] When a hose molded body 4A having a reinforcing layer 6 formed by reinforcing cords 6a made of resin fibers is molded and vulcanized to manufacture a hose 4, the reinforcing cords 6a shrink due to heat after the manufacture of the hose 4. As a result, the outer surface 2a of the mandrel 1 and the inner surface 5a of the hose 4 adhere more tightly, making it difficult to pull the mandrel 1 out of the hose 4. According to the present invention, even when manufacturing a hose 4 with such specifications, it becomes easier to remove the mandrel 1 from the hose 4. Therefore, the present invention is particularly useful when manufacturing a hose 4 with such specifications. [Explanation of Symbols]

[0056] 1 Mandrel 2. Outer layer (outermost resin layer) 2a Outer surface 3 core 4 hoses 4A Hose molded body 5. Inner Layer 5a Inner surface 6. Reinforcement layer 6a Reinforcement cord 7. Intermediate rubber layer 8 Outer layer 9 Covering material 10 Vulcanizing apparatus 11. Molten resin removal device 11a Suction means 11b Head section 11c Passageway 11d Lid

Claims

1. In a method for manufacturing a hose, in which a hose molded body formed on the outer surface of a mandrel is vulcanized to produce a hose, A method for manufacturing a hose, comprising: in the vulcanization process of the hose molded body, after the hose molded body has reached a predetermined vulcanized state, the outermost resin layer of the mandrel is melted, the thickness of the outermost resin layer is 1 mm or more; the melted resin is removed from the inside of the vulcanized hose; the unmelted portion of the mandrel is then pulled out from the inside of the hose to manufacture the hose; and the unmelted portion of the mandrel that was pulled out is laminated with resin on its outer surface to regenerate it as a mandrel.

2. In a method for manufacturing a hose, in which a hose molded body formed on the outer surface of a mandrel is vulcanized to produce a hose, A method for manufacturing a hose, in which a resin mandrel is used as the mandrel, and after the hose molded body reaches a predetermined vulcanized state during the vulcanization process of the hose molded body, the core of the mandrel is melted to remove the molten resin from inside the vulcanized hose, and then the unmelted portion of the mandrel is pulled out from inside the hose to manufacture the hose.

3. In a method for manufacturing a hose, in which a hose molded body formed on the outer surface of a mandrel is vulcanized to produce a hose, A method for manufacturing a hose, in which a resin mandrel is used as the mandrel, and after the hose molded body reaches a predetermined vulcanized state during the vulcanization process of the hose molded body, the entire mandrel is melted, and the molten resin is removed from the inside of the vulcanized hose to manufacture the hose.

4. In a mandrel placed inside a vulcanizing apparatus together with a hose molded on its outer surface, A mandrel having an outermost resin layer that is molten after the hose molded body reaches a predetermined vulcanized state in the vulcanization process of the hose molded body using the vulcanizing apparatus, wherein the thickness of the outermost resin layer is 1 mm or more, and the molten resin is removed and the remaining portion is regenerated by laminating resin onto the outer surface of the mandrel.

5. In a mandrel placed inside a vulcanizing apparatus together with a hose molded on its outer surface, A mandrel whose entire body is made of resin, and which has a core that is molten after the hose molded body reaches a predetermined vulcanized state in the vulcanization process of the hose molded body using the vulcanization apparatus, and which is regenerated by filling the interior of the remaining portion after the molten resin has been removed with resin.

6. In a mandrel placed inside a vulcanizing apparatus together with a hose molded on its outer surface, A mandrel, which is entirely made of resin, and which is molten after the hose molded body reaches a predetermined vulcanized state during the vulcanization process of the hose molded body using the vulcanization apparatus.

Images