Flexible tube manufacturing equipment, flexible tube manufacturing method

Abstract

To provide a flexible pipe manufacturing apparatus which can respond to the formation of a flexible pipe with a sudden change in flexibility and can make the wall thickness of the resin coated in the circumferential direction of the core material of the flexible pipe uniform.SOLUTION: A flexible pipe manufacturing apparatus 1 for coating the periphery of a core material of a flexible pipe with resin, comprising: a first tubular member 31 into which the core material is inserted; a second tubular member 32 into which the first tubular member is inserted to form a first flow passage 41 between itself and the second tubular member; a hollow member 33 into which the second tubular member is inserted to form a second flow passage 42 between itself and the second tubular member; a first nozzle 34 connected to one end of the first tubular member; the second nozzle 35 is connected to one end of the second cylindrical member and merges the first and second channels, and the drive unit 37 rotates at least one of the first cylindrical member, the first nozzle, the second cylindrical member, and the second nozzle in the circumferential direction of the core material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a manufacturing apparatus and method for a flexible tube used in, for example, an endoscope. [Background technology]

[0002] In general, flexible tubes used in endoscopes and the like are configured with their outer peripheries coated with resin, and endoscopes and the like are configured with flexibility that changes appropriately from the distal end region to the proximal end region.

[0003] As conventional manufacturing methods for coating a core material of a flexible tube used in an endoscope or the like with a resin, for example, a mixed manufacturing method, a two-layer manufacturing method, etc. are generally used.

[0004] The above-mentioned mixing method involves joining two different types of resin in a molten state and supplying them onto the surface of a rotating core material (mandrel).The two types of resin are then coated onto the outer periphery of the core material of the flexible tube while still in a molten state, and then solidified to form a coating.

[0005] On the other hand, the two-layer manufacturing method is a manufacturing method in which two different types of resin are melted and not mixed together, but are coated by changing the state from a single layer to a laminated state near the die (the part with a supply port that supplies the resin and applies it to the outer periphery of the core material).

[0006] In the above-mentioned mixing method, the flexibility of the flexible tube after resin coating can be adjusted to the desired flexibility by changing the blending ratio of the two types of resin that are merged. Furthermore, this mixing method has the advantage that the resin can be molded to have a substantially uniform wall thickness around the circumferential direction of the core material of the flexible tube, because the molten resin is coated onto the outer periphery of the core material of the flexible tube while the mandrel is rotating.

[0007] On the other hand, with the two-layer manufacturing method, the desired flexibility of the flexible tube after resin coating can be achieved by adjusting the thickness of each resin layer. In this case, the thickness of each resin layer is changed by adjusting the amount of resin supplied. The two-layer manufacturing method has the advantage that the flexibility can be changed over an extremely short distance because the amount of resin supplied can be changed suddenly.

[0008] For example, Japanese Patent No. 2841913 discloses a blow molding method for coating a resin using a two-layer method. Japanese Patent Application Laid-Open No. 2012-101522 discloses a rotary feedblock manufacturing method for extrusion molding a multilayer cylindrical resin, in which multiple resins are injected to divide the circumference of the cylindrical cross section into multiple sections, and at least one of the nozzle and the mandrel is rotated to stretch each divided section spirally, so that the multiple resins form multiple layers. Japanese Patent Application Laid-Open No. 2016-67566 and Japanese Patent Application Laid-Open No. 6966549 disclose methods for manufacturing a flexible tube for an endoscope using a two-layer method. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 2841913 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-101522 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-67566 [Patent Document 4] Patent No. 6966549 etc. Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the conventional mixing method, two types of molten resin are joined together and then coated onto the outer periphery of the core material of the flexible tube, which has the problem that it is difficult to mold flexible tubes with sudden changes in flexibility.

[0011] For example, the larger the volume of the area where the two types of resins flow after joining, the longer it takes to switch between the resins, making it impossible to mold flexible tubes with sudden changes in flexibility. Therefore, with the conventional mixed manufacturing method, it was difficult to adjust the flexibility of the flexible tube as intended at each location along its length.

[0012] On the other hand, the two-layer (multi-layer) manufacturing methods disclosed in the above-mentioned Patent Publication No. 2841913, the above-mentioned Patent Publication No. 2012-101522, the above-mentioned Patent Publication No. 2016-67566, the above-mentioned Patent Publication No. 6966549, etc., involve laminating resin around the outer periphery of the core material of the flexible tube, which poses the problem of making it difficult to make the thickness of the resin coating the circumferential direction of the core material of the flexible tube approximately uniform.

[0013] Furthermore, in the conventional two-layer manufacturing method, the amount of resin supplied is adjusted by the extrusion pressure. Therefore, if the resin supply ratio is suddenly changed to adjust the flexibility of the flexible tube, for example, the resin supply becomes unstable, which can result in areas on the core surface that are not covered with resin. Therefore, in the conventional two-layer manufacturing method, it is necessary to control the resin extrusion pressure with high precision.

[0014] In the technology disclosed in the above-mentioned JP 2012-101522 A, although it is possible to ensure a substantially uniform wall thickness in the circumferential direction by rotating the nozzle or mandrel, there arises a problem in that it becomes difficult to adjust the flexibility as intended at each longitudinal position of the flexible tube.

[0015] Conventionally, flexible tube manufacturing apparatuses and methods for manufacturing flexible tubes used in endoscopes and the like have been able to mold flexible tubes with sudden changes in flexibility without leaving any areas on the core material surface that are not covered with resin. Furthermore, there has always been a demand for a generally uniform wall thickness of the resin coating around the circumferential direction of the core material of the flexible tube. However, no flexible tube manufacturing apparatus or method has existed that can satisfy all of these requirements.

[0016] The object of the present invention is to provide a flexible tube manufacturing apparatus and a flexible tube manufacturing method that can accommodate the molding of flexible tubes with sudden changes in flexibility without leaving any areas on the core material surface that are not coated with resin, and that can make the thickness of the resin coated around the circumferential direction of the core material of the flexible tube approximately uniform. [Means for solving the problem]

[0017] In order to achieve the above object, one aspect of the present invention provides a flexible tube manufacturing apparatus that coats the outer periphery of a core material of a flexible tube with a resin, the core material being inserted into , and a spiral first groove is formed on the outer periphery. a first cylindrical member, the first cylindrical member being inserted therein; A second spiral groove is provided on the outer periphery. The core material includes a second tubular member that forms a first flow path between itself and the first tubular member, a hollow member into which the second tubular member is inserted and that forms a second flow path between itself and the second tubular member, a first nozzle connected to one end of the first tubular member, a second nozzle connected to one end of the second tubular member and that merges the first flow path and the second flow path, and a drive unit that rotates at least one of the first tubular member, the first nozzle, the second tubular member, and the second nozzle in the circumferential direction of the core material.

[0018] A manufacturing method of a flexible tube according to one aspect of the present invention is a manufacturing method of a flexible tube in which a resin is coated on the outer periphery of a core material of the flexible tube, the manufacturing method comprising: supplying a first resin to a first flow path provided along the outer periphery of the core material; supplying a second resin to a second flow path provided along the outer periphery of the core material outside the first flow path; rotating at least one of the first flow path, the second flow path, and a confluence flow path provided at the tip of the first flow path and the second flow path in a circumferential direction of the core material; A spiral first groove provided in the first resin passing through the second flow path A spiral second groove is provided in the The second resin that has passed through the second resin is applied to the outer periphery of the core material. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a flexible tube manufacturing device and a flexible tube manufacturing method that can accommodate the molding of flexible tubes with sudden changes in flexibility without creating areas on the core material surface that are not covered with resin, and that can make the thickness of the resin that covers the circumferential direction of the core material of the flexible tube approximately uniform. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a conceptual diagram showing an outline of the overall configuration of a flexible tube manufacturing apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a simplified configuration of a resin coating device in the flexible tube manufacturing apparatus of FIG. [Figure 3] 3 is a schematic perspective view showing only a first cylindrical member (inner layer mandrel) in the resin coating apparatus of FIG. 2; [Figure 4] 3 is a schematic perspective view showing only a second cylindrical member (outer layer mandrel) in the resin coating apparatus of FIG. [Figure 5] A conceptual diagram showing the general configuration of the take-up machine in the flexible tube manufacturing apparatus of FIG. [Figure 6] FIG. 6 is a diagram for explaining the operation of the take-up machine of FIG. 5, showing the state of the long flexible tube being transported after the state of FIG. 5. [Figure 7] An enlarged view of the area indicated by the symbol [7] in Figure 6. [Figure 8] FIG. 10 is an enlarged view of a main part showing a modification of the first embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing a simplified configuration of a resin coating device in a flexible tube manufacturing apparatus according to a second embodiment of the present invention. [Figure 10] 10 is a schematic perspective view showing only a second cylindrical member (outer layer mandrel) in the resin coating apparatus of FIG. 9. FIG. [Figure 11] FIG. 10 is a cross-sectional view showing a simplified configuration of a resin coating device in a flexible tube manufacturing apparatus according to a third embodiment of the present invention. [Figure 12] 12 is a schematic perspective view showing only a rotating shaft for rotating a first nozzle (inner layer nozzle) in the resin coating apparatus of FIG. 11. [Figure 13]12 is a schematic perspective view showing only the first cylindrical member (inner layer mandrel) in the resin coating apparatus of FIG. 11; DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described below with reference to the illustrated embodiments. The drawings used in the following description are schematic, and the dimensional relationships and scales of the components may be different for each component in order to show each component at a size that allows it to be recognized on the drawing. Therefore, the present invention is not limited to the illustrated embodiments in terms of the number of components shown in the drawings, the shapes of the components, the size ratios of the components, the relative positional relationships of the components, and so on.

[0022] [First embodiment] First, an outline of the overall configuration of a flexible tube manufacturing apparatus according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a conceptual diagram showing an outline of the overall configuration of a flexible tube manufacturing apparatus according to the first embodiment of the present invention.

[0023] The flexible tube manufacturing apparatus 1 of this embodiment is a flexible tube manufacturing apparatus that coats the outer periphery of a core material of a flexible tube used in an endoscope, etc. As shown in Fig. 1, this flexible tube manufacturing apparatus 1 is composed of a control device 10, a resin coating device 11, a cooling device 12, a conveying device 13, etc.

[0024] The control device 10 controls the entire flexible tube manufacturing apparatus 1, and also controls the operations of the resin coating device 11, the cooling device 12, the transport device 13, and the like as appropriate.

[0025] All or part of the control device 10 is configured by a processor including hardware. Here, the processor is configured by a well-known configuration including, for example, a central processing unit (CPU), random access memory (RAM), read only memory (ROM), non-volatile memory, non-volatile storage, and non-transitory computer readable medium, as well as peripheral devices thereof.

[0026] Software programs to be executed by the CPU and fixed data such as data tables are stored in advance in ROM, nonvolatile memory, nonvolatile storage devices, etc. The CPU reads out the software programs stored in ROM, etc., expands them into RAM, and executes them, and the software programs refer to various data, etc. as appropriate, thereby realizing various controls by the control device. The processor may also be configured with a semiconductor chip such as an FPGA (Field Programmable Gate Array).

[0027] The resin coating device 11 is a main component device that is responsible for the process of coating the outer periphery of a core material of a flexible tube used in an endoscope, etc. The resin coating device 11 is appropriately driven and controlled under the control of the control device 10. The detailed configuration of the resin coating device 11 will be described later with reference to Figs. 2 to 4.

[0028] The cooling device 12 is a device that performs cooling in order to solidify the resin that has been coated on the outer periphery of the core material of the flexible tube by the resin coating device 11. The cooling device 12 may be appropriately driven and controlled under the control of the control device 10. As the cooling device 12 is a conventionally well-known device, a detailed description of its configuration will be omitted. Note that FIG. 1 illustrates a water-cooled cooling device as an example of the cooling device 12. Furthermore, if natural cooling or the like is used, the cooling device 12 may not be necessary.

[0029] The conveying device 13 is composed of a supplying device 21 including a supply drum 22, and a taking-up device 23 including a take-up machine 24 and a winding drum 25. In the conveying device 13, the supplying device 21 and the taking-up device 23 are driven independently. Alternatively, the supplying device 21 and the taking-up device 23 may be configured to be appropriately driven and controlled under the control of the control device 10.

[0030] The supply device 21 is a device that performs drive control of the supply drum 22 under the control of the control device 10. The supply drum 22 is a device that winds a long core material in the form of multiple core materials (100) connected by connecting dummy tubes (101). In the following explanation, the long core material will be referred to by adding the reference number 100. The reference number 100 in parentheses will be used when referring to an individual core material.

[0031] The take-up machine 24 is a device that, under the control of the control device 10, transports the flexible tube (102) after the outer periphery of the core material (100) has been coated with resin, and controls the drive of the winding drum 25. The winding drum 25 is a drum that winds up the resin-coated flexible tube (102).

[0032] Here, the individual resin-coated flexible tubes (102) are connected to each other by the above-mentioned connecting dummy tubes (101). Therefore, in the following description, a long flexible tube in which multiple resin-coated flexible tubes (102) are connected to each other by the individual connecting dummy tubes (101) will be referred to as a long flexible tube and will be designated by the reference numeral 102. The reference numeral 102 in parentheses is used to designate individual resin-coated flexible tubes. The schematic configuration of the flexible tube manufacturing apparatus 1 of this embodiment has been described above.

[0033] Next, the detailed configuration of the resin coating device 11 in the flexible tube manufacturing apparatus 1 of this embodiment will be described below with reference to Figs. 2 to 4. Fig. 2 is a cross-sectional view showing a simplified configuration of the resin coating device in the flexible tube manufacturing apparatus of the first embodiment of the present invention. Fig. 3 is a schematic perspective view showing only the first cylindrical member (inner layer mandrel) in the resin coating device of Fig. 2. Fig. 4 is a schematic perspective view showing only the second cylindrical member (outer layer mandrel) in the resin coating device of Fig. 2.

[0034] 2, and as described above, the resin coating apparatus 11 is appropriately driven and controlled under the control of the control device 10. The resin coating apparatus 11 is configured to include an inner layer mandrel 31 which is a first cylindrical member, an outer layer mandrel 32 which is a second cylindrical member, a hollow member 33, an inner layer nozzle 34 which is a first nozzle, an outer layer nozzle 35 which is a second nozzle, a die 36, a drive unit 37, a first resin supply device 38, a second resin supply device 39, a heating device 40, and the like.

[0035] The inner layer mandrel 31 is a component through which the elongated core material 100 is inserted and which acts to uniformly disperse the first resin 38x (described below) supplied to the outer periphery in the circumferential direction and to extrude it toward the die outlet, thereby supplying it to the outer periphery of the inner layer nozzle 34. Therefore, as shown in FIG. 3, the inner layer mandrel 31 has openings 31a and 31b at its front end (one end) and rear end (the other end), and is formed into a generally cylindrical shape overall. The inner layer mandrel 31 is formed with a helical groove 31e, which is a helical circumferential groove, on the outer periphery of the tip region 31c. This helical groove 31e is formed over substantially the entire outer periphery of the tip region 31c of the inner layer mandrel 31.

[0036] In addition to the above-described example of the spiral groove 31e being configured as a single spiral extending over the entire outer periphery of the inner layer mandrel 31, the following configurations are also possible. For example, the spiral groove 31e may be configured to branch into multiple spiral grooves (double spirals, quadruple spirals, etc.) from the supply point where the first resin 38x is supplied. In such a configuration, a branching portion may be provided near the supply point where the first resin 38x is supplied, and multiple spiral grooves may be formed from this branching point. By configuring the spiral groove 31e in this way as a multiple spiral, the supplied first resin 38x can be configured to be fed approximately uniformly toward the outer periphery of the inner layer nozzle 34.

[0037] Here, the first supply port 38a of the first resin supplier 38 is positioned in the middle of the tip region 31c on the outer periphery of the inner layer mandrel 31 (see FIG. 2). Therefore, a portion of the spiral groove 31e provided in the region 31ca on the tip side of the outer periphery of the tip region 31c of the inner layer mandrel 31 serves to uniformly disperse the first resin 38x in the circumferential direction and to extrude it toward the die outlet, thereby supplying it to the outer periphery of the inner layer nozzle 34. Meanwhile, the inner layer mandrel 31 in this embodiment also has a portion of the spiral groove 31e formed in the region 31cb closer to the rear end than the middle of the outer periphery of the tip region 31c. The reason for this configuration is as follows.

[0038] Normally, the first resin 38x from the first supply port 38a does not flow through the spiral groove 31e located in the region 31cb. However, during operation of the flexible tube manufacturing apparatus 1, the first resin 38x, which normally flows toward the tip side through the first flow path 41 (described later), may flow back through the first flow path 41 toward the first supply port 38a under certain conditions.

[0039] Specifically, for example, when the first resin 38x supplied from the first supply port 38a flows toward the first flow path 41 (tip side) after being subjected to the actions of uniformly dispersing the resin 38x circumferentially around the outer periphery of the inner layer mandrel 31 and pushing it toward the die outlet, the flow of the first resin 38x may stagnate in the tip side of the first flow path 41.

[0040] At this time, the pressure at the tip end of the first flow path 41 increases. As a result, the first resin 38x may flow back through the first flow path 41 toward the first supply port 38a. Therefore, to prevent the pressure at the tip end of the first flow path 41 from exceeding a certain pressure, the spiral groove 31e is also formed in the region 31cb of the inner layer mandrel 41. By forming the spiral groove 31e in the region 31cb, the first resin 38x that flows back for the above-mentioned reason is prevented from entering the inside of the first resin supply device 38 through the first supply port 38a. At the same time, a portion of the spiral groove 31e in the region 31cb is extended to form a space for eliminating the pressure difference between the tip and rear ends of the first flow path 41 and for evacuating the first resin 38x that flows back. Furthermore, when the pressure at the tip side within the first flow path 41 returns to normal and the backflow of the first resin 38x within the first flow path 41 is eliminated, the resin that has flowed out into the extension portion of the spiral groove 31e also flows out toward the tip side of the first flow path 41.

[0041] The inner layer mandrel 31 is formed in a tapered shape such that the outer diameter at the tip side becomes thinner toward the tip. An inner layer nozzle 34 is provided at the tip opening 31a of the inner layer mandrel 31. In this case, the inner layer nozzle 34 is configured separately from the inner layer mandrel 31, and the inner layer nozzle 34 is fixed to a predetermined fixing portion.

[0042] The inner layer nozzle 34 is a component provided to coat the outer periphery of the core material (100) with the two types of resin obtained after the first resin 38x and the second resin 39x join together. This inner layer nozzle 34 is also formed in a tapered shape, with the outer diameter of the tip side narrowing toward the tip. Note that the tip side of the inner layer nozzle 34 here refers to the side not connected to the inner layer mandrel 31.

[0043] Meanwhile, the outer periphery of the rear end region 31d of the inner layer mandrel 31 is rotatably supported by a bearing member 37c (see FIG. 2). A drive unit 37 is connected to the rear end region 31d of the inner layer mandrel 31, as shown in FIG.

[0044] The drive unit 37 is a structural unit that rotates the inner layer mandrel 31 in a direction along the circumferential direction of the core material (100) that is inserted into the inner layer mandrel 31. The drive unit 37 is configured with a drive motor 37a and a drive force transmission mechanism 37b. Here, the drive motor 37a is a drive source that generates a rotational drive force for rotating the inner layer mandrel 31. The drive force transmission mechanism 37b is a mechanical part that transmits the rotational drive force of the drive motor 37a to the inner layer mandrel 31. As an example of the drive force transmission mechanism 37b, Figure 2 illustrates a belt-driven drive force transmission mechanism that is configured with a pulley fixed coaxially to the drive shaft of the drive motor 37a, a pulley fixed coaxially with the inner layer mandrel 31 in the rear end region 31d of the inner layer mandrel 31, and a belt connecting the two pulleys. The form of the driving force transmission mechanism 37b is not limited to the example shown in FIG. 2, and may be configured in other forms (for example, a form using a plurality of gears, etc.).

[0045] In this manner, in this embodiment, only the inner layer mandrel 31 is rotated by the drive unit 37 .

[0046] However, the configuration of the inner layer mandrel 31 and the inner layer nozzle 34 is not limited to the above-described configuration example. For example, the inner layer nozzle 34 may be configured to be integrally connected to the tip of the inner layer mandrel 31. In this configuration, when the drive unit 37 rotates the inner layer mandrel 31 using the above-described configuration, it is possible to similarly rotate the inner layer nozzle 34 in the same direction at the same rotational speed.

[0047] In the inner layer mandrel 31 configured in this manner, the supply speed and supply amount of the first resin 38x are appropriately adjusted by the groove depth and groove pitch of the spiral groove 31e, the rotation speed of the drive unit 37, and the like.

[0048] The outer layer mandrel 32 is a component into which the inner layer mandrel 31 is inserted and which supplies the second resin 39x (described later) supplied to its outer periphery to the outer periphery of the outer layer nozzle 35. To this end, the outer layer mandrel 32 has openings 32a and 32b at its front end (one end) and rear end (the other end), as shown in FIG. 4, and is formed into a generally cylindrical shape overall. In this case, the inner diameter of the outer layer mandrel 32 is formed slightly larger than the outer diameter of the inner layer mandrel 31. This allows the inner layer mandrel 31 to be inserted into the outer layer mandrel 32 in a rotatable manner.

[0049] The outer layer mandrel 32 is also formed with a spiral groove 32e, which is a spiral circumferential groove, on the outer periphery of the tip region 32c. The spiral groove 32e has a branching portion 32g that branches into multiple spiral grooves (double spirals, quadruple spirals, etc.) from a supply point 32f where the second resin 39x is supplied. By forming the spiral groove 32e in this manner as a multiple spiral, the supplied second resin 39x is designed to be sent approximately uniformly toward the outer periphery of the outer layer nozzle 35. The configuration of the spiral groove 32e is not limited to the above example, and may be, for example, a configuration consisting of a single spiral groove extending from a resin supply port.

[0050] Similarly to the spiral groove 31e of the inner layer mandrel 31, the spiral groove 32e of the outer layer mandrel 32 may also be provided up to the region 32d near the rear end, to serve as a space for evacuating the backflow resin.

[0051] The outer layer mandrel 32 is also formed in a tapered shape, with the outer diameter at the tip end narrowing toward the tip. Similarly, the inner diameter at the tip end of the outer layer mandrel 32 is also formed in a tapered shape, with the inner diameter at the tip end narrowing toward the tip. An outer layer nozzle 35 is provided at the tip opening 32a of the outer layer mandrel 32. In this case, the outer layer nozzle 35 is integrally connected to the outer layer mandrel 32. Alternatively, the outer layer mandrel 32 and the outer layer nozzle 35 may be formed separately, and each may be fixed to a predetermined fixing portion.

[0052] The outer layer nozzle 35 is a component provided to merge with the first flow path 41 and the second flow path 42 described below. Here, the outer layer nozzle 35 is also formed with a tapered shape in which the outer diameter and inner diameter at the tip end become narrower toward the tip. In this case, the tapered shape at the tip end of the outer layer nozzle 35 is formed with different taper angles on the outer peripheral side and the inner peripheral side. In this case, the taper angle at the tip end of the outer layer nozzle 35 on the outer peripheral side relative to the longitudinal axis through which the core material 100 is inserted is formed to be more obtuse than the taper angle at the inner peripheral side of the outer layer nozzle 35.

[0053] The tapered tip shape on the inner periphery of the outer layer mandrel 32 and the tapered tip shape on the inner periphery of the outer layer nozzle 35 are formed to be approximately continuous. The continuous tapered tip shapes on the inner periphery of the outer layer mandrel 32 and the outer layer nozzle 35 are shaped to follow the tapered tip shape on the outer periphery of the inner layer mandrel 31.

[0054] A gap having a predetermined distance therebetween is formed in the circumferential direction between the inner circumferential surfaces of the outer layer mandrel 32 and the outer layer nozzle 35 and the outer circumferential surface of the inner layer mandrel 31. This gap serves as a first flow path 41 through which a first resin 38x (described later) flows. This first flow path 41 is provided along the outer periphery of the core material of the flexible tube.

[0055] The outer layer mandrel 32 configured in this manner is fixed in the rear end region 32d to the interior near the rear end and rear end face of the hollow member 33. For this reason, a flange portion 32h is formed at the rear end of the outer layer mandrel 32 to ensure fixation to the hollow member 33. In addition, a through hole 32k for a first supply port 38a of a first resin supply device 38 (described later) is formed in a middle portion of the outer layer mandrel 32, penetrating from the outer peripheral surface to the inner peripheral surface.

[0056] As described above, the outer layer mandrel 32 is fixed in the resin coating apparatus 11 and is therefore immovable. Therefore, the outer layer nozzle 35, which is integrally connected to the outer layer mandrel 32, is also immovable. Alternatively, if the outer layer mandrel 32 and the outer layer nozzle 35 are configured separately, they are both fixed to predetermined fixing portions and are immovable.

[0057] An outer layer mandrel 32 and a die 36 are inserted inside the hollow member 33. An inner layer nozzle 34 and an outer layer nozzle 35 are arranged inside this die 36, and a flow path is formed between the outer surface of each nozzle 34, 35 and the inner surface of the die 36 through which the molten resins (38x, 39x) flow and then guide them to the outer periphery of the core material (100) (details will be described later).

[0058] At the same time, the die 36 is provided at a portion where the long flexible tube 102, after the outer periphery of the core material (100) has been coated with resin, is sent out to the outside of the resin coating device 11. At this time, the die 36 has the function of adjusting the resin coating the outer periphery of the core material (100) to a specified thickness.

[0059] The hollow member 33 has openings at its front end (one end) and rear end (the other end), and is formed with a hollow portion that penetrates from the front end opening to the rear end opening. In this case, the outer layer mandrel 32 is inserted into the hollow portion of the hollow member 33 from the rear end side. Then, the rear end region 32d of the outer layer mandrel 32 is fixed to the hollow member 33.

[0060] In addition, a die 36 is fixed inside the tip of the hollow portion of the hollow member 33. An inner layer nozzle 34 and an outer layer nozzle 35 are arranged inside this die 36 (at the engaging portion 36a described later). Note that a portion of the tip of the outer layer mandrel 32 may be arranged inside the die 36. In this case, the inner diameter of the approximately rear half region of the hollow member 33 (see the region indicated by symbol 33d in Figure 2) and the outer diameter of the rear end region 32d of the outer layer mandrel 32 are approximately the same diameter, and the inner diameter of the hollow member 33 is slightly larger than the outer diameter of the outer layer mandrel 32. With this configuration, the hollow member 33 has the outer layer mandrel 32 inserted inside and fixes the rear end region 32d of the outer layer mandrel 32.

[0061] The inner peripheral side of the die 36 provided inside the tip of approximately the front half region of the hollow member 33 is formed in a tapered shape that is approximately the same shape as the tapered tip shapes on the outer peripheral sides of the outer layer mandrel 32, outer layer nozzle 35, and inner layer nozzle 34. Here, a gap having a predetermined distance in the circumferential direction is formed between the inner peripheral surface of approximately the front half region of the hollow member 33 and the outer peripheral surface of the tip region 32c of the outer layer mandrel 32. This gap forms part of a second flow path 42 through which a second resin 39x, described below, flows. This second flow path 42 is located outside the first flow path 41 and is provided along the outer periphery of the core material of the flexible tube.

[0062] As described above, the die 36 is fixed inside the tip of the hollow portion of the hollow member 33. This die 36 is provided on the outer peripheral side of the inner layer nozzle 34 and the outer layer nozzle 35. The die 36 is formed with an engaging portion 36a having an inner surface formed in a shape that follows the outer peripheral shape (tapered tip shape) of the tip (one end) of the inner layer nozzle 34 and the outer layer nozzle 35, and a through hole 36b through which the long flexible tube 102 is inserted and passes after being coated with resin.

[0063] Here, a continuous gap is formed between the inner surface of the engaging portion 36a and the outer peripheral surfaces of the tapered tips of the inner layer nozzle 34 and the outer layer nozzle 35. Of these, the gap between the inner surface of the engaging portion 36a and the outer peripheral surface of the tapered tip of the outer layer nozzle 35 is part of the second flow path 42 through which the second resin 39x flows. Furthermore, the gap between the inner surface of the engaging portion 36a and the outer peripheral surface of the tapered tip of the inner layer nozzle 34 is part of the confluence flow path 43 through which the resin flows after the first resin 38x and the second resin 39x are joined. In other words, in this embodiment, the outer layer nozzle 35 has the first flow path 41 on the inner peripheral side and the second flow path 42 on the outer peripheral side joined at the tip.

[0064] Then, the long flexible tube 102 coated with resin is inserted through the through-hole 36b of the die 36, so that the resin coated on the outer periphery of the core material (100) has a specified thickness.

[0065] The first resin supply machine 38 is a resin supply device that stores the first resin 38x in a molten state and applies a predetermined supply pressure to the first resin 38x at a predetermined timing to supply the first resin 38x to the first flow path 41. The first resin supply machine 38 is appropriately driven and controlled under the control of the control device 10. To this end, the first resin supply machine 38 has a storage section that stores the first resin 38x in a molten state and a first supply port 38a that supplies the first resin 38x in the storage section to the first flow path 41.

[0066] The second resin supply machine 39 is a resin supply device that stores the second resin 39x in a molten state and applies a predetermined supply pressure to the second resin 39x at a predetermined timing to supply the second resin 39x to the second flow path 42. The second resin supply machine 39 is appropriately driven and controlled under the control of the control device 10. To this end, the second resin supply machine 39 has a storage section that stores the second resin 39x in a molten state and a second supply port 39a that supplies the second resin 39x in the storage section to the second flow path 42.

[0067] The first resin 38x and the second resin 39x have different hardness or viscosity. The first resin 38x and the second resin 39x are different types of resin. In this case, types of resin that can be used include ester-based resins, urethane-based resins, etc.

[0068] The heating device 40 heats at least one of the inner layer mandrel 31, the outer layer mandrel 32, and the hollow member 33. By heating at least one of the above units (31, 32, 33), the heating device 40 serves to maintain a molten state of the resins (38x, 39x, etc.) supplied to the flow paths (41, 42, 43) from the first resin supply device 38 and the second resin supply device 39. To this end, the heating device 40, under the control of the control device 10, performs appropriate temperature adjustment control and the like depending on the resin supplied to each flow path.

[0069] In the flexible tube manufacturing apparatus 1 of this embodiment, the resins supplied to each flow path from the first resin supply device 38 and the second resin supply device 39 are supplied in a molten state. For this reason, the heating device 40 is not necessarily an essential component of the flexible tube manufacturing apparatus 1 of this embodiment. However, by providing the heating device 40, it is possible to appropriately control the temperature of the molten resin supplied to each flow path so that it always remains easy to flow. Therefore, by providing the heating device 40, it is possible to always maintain the resin flow in an appropriate state, which has the advantage of always being able to apply the resin to the outer periphery of the core material in a generally uniform and stable manner. The resin coating device 11 in the flexible tube manufacturing apparatus 1 of this embodiment is configured as described above.

[0070] Next, the configuration of the take-up machine 24 in the flexible tube manufacturing apparatus 1 of this embodiment will be described below with reference to FIGS. 5 to 7. FIG. 5 is a diagram conceptually showing the schematic configuration of the take-up machine in the flexible tube manufacturing apparatus of this embodiment. FIG. 5 shows a state in which a long flexible tube 102 is inserted into the take-up machine 24. FIGS. 6 and 7 are diagrams for explaining the operation of the take-up machine 24. Of these, FIG. 6 is a diagram showing the state in which the long flexible tube 102 is being transported after the state in FIG. 5. In the state shown in FIG. 6, the connection portion (101) of the long flexible tube 102 passes through the inside of the take-up machine 24. FIG. 7 is an enlarged view showing an area indicated by the symbol [7] in FIG. 6. The operation of the flexible tube manufacturing apparatus 1 of this embodiment, including the operation of the take-up machine 24, will be described later.

[0071] The take-up machine 24 in the flexible tube manufacturing apparatus 1 of this embodiment is a so-called belt-type take-up machine, as shown in Fig. 5. The take-up machine 24 is a device for clamping the long flexible tube 102 after the outer periphery thereof has been coated with resin and solidified in the radial direction (vertical direction) of the long flexible tube 102, and transporting the long flexible tube 102 in a predetermined direction at a predetermined speed.

[0072] For this purpose, the take-up machine 24 is appropriately driven and controlled under the control of the control device 10, as shown in FIG. 5 and the like, and as described above.

[0073] The take-up machine 24 is composed of an upper belt 24a, a lower belt 24b, a pressure cylinder 24c, a plurality of cylinders 24d, a base 24e, and the like.

[0074] The upper belt 24a and the lower belt 24b are components for sandwiching the long flexible tube 102 after its outer periphery is coated with resin in the radial direction (vertical direction) of the long flexible tube 102 and transporting it in a predetermined direction at a predetermined speed. The upper belt 24a and the lower belt 24b convert the rotational driving force of a rotational driving mechanism (not shown) into a horizontal transport direction T (see FIG. 5).

[0075] The upper belt 24a, the lower belt 24b and the rotation drive mechanism (not shown) are driven under the control of the control device 10. The control device 10 controls the rotation speed of the rotation drive mechanism (not shown) to adjust the movement speed of the upper belt 24a and the lower belt 24b, and controls the take-up speed of the long flexible tube 102.

[0076] The lower belt 24b is fixed to a base 24e, and the belt surface of the lower belt 24b is maintained substantially horizontal.

[0077] The pressure cylinder 24c is a device that drives the upper belt 24a in the up and down direction. The pressure cylinder 24c adjusts the pressure under the control of the control device 10. The pressure cylinder 24c adjusts the pressure applied in the radial direction to the outer periphery of the long flexible tube 102 sandwiched between the upper belt 24a and the lower belt 24b so that it is always at an appropriate pressure. This pressure adjustment is performed, for example, to prevent the long flexible tube 102 from collapsing or slipping during transport.

[0078] The pressure cylinder 24c drives the plurality of cylinders 24d and the upper belt up and down. Each of the plurality of cylinders 24d includes one cylinder portion 24da, at least one roller 24db, and a connecting mechanism 24dc.

[0079] For example, this embodiment illustrates an example of a configuration including one cylinder portion 24da, two rollers 24db, and a connecting mechanism 24dc. In this configuration example, the one cylinder portion 24da and the two rollers 24db are connected by the connecting mechanism 24dc. The connecting mechanism 24dc has a cylinder shaft of the cylinder portion 24da and a link mechanism that connects the two rollers 24db and holds the two rollers 24db so that they can swing around the cylinder shaft.

[0080] Furthermore, the two rollers 24db are each axially supported by a link mechanism so as to be independently rotatable. In this case, the rotation direction R of the roller 24db (see FIG. 7) is rotation around a rotation axis in a direction substantially perpendicular to the conveying direction T of the long flexible tube 102 (horizontal direction, parallel to each belt surface; see FIGS. 5 and 7). Note that although only one-way arrows are shown in FIG. 7 as the rotation direction R of the roller 24db, in reality, the roller 24db itself is rotatable forward and backward. The rotation direction R shown in FIG. 7 indicates the rotation direction of each roller 24db when the long flexible tube 102 is being conveyed.

[0081] The operation of the flexible tube manufacturing apparatus 1 of this embodiment configured as above will be described below.

[0082] 1, the connecting dummy tube 101 at one end of the long core material 100 wound around the supply drum 22 is inserted along a predetermined path in the flexible tube manufacturing apparatus 1, and then fixed to the winding drum 25. As a result, the long core material 100 wound around the supply drum 22 is sequentially pulled out at a predetermined speed in a predetermined winding direction by driving the take-up machine 24, and is ready to be wound by the winding drum 25.

[0083] Furthermore, the first resin supply machine 38 is filled with a first resin 38x in a molten state. Similarly, the second resin supply machine 39 is filled with a second resin 39x in a molten state. The control device 10 controls the heating device 40 to start temperature adjustment control according to the first resin 38x and the second resin 39x.

[0084] In this state, the flexible tube manufacturing apparatus 1 is operated. First, the control device 10 drives and controls the drive unit 37 to rotate the inner layer mandrel 31. At the same time, the control device 10 drives and controls the first resin supply device 38 and the second resin supply device 39 to apply a predetermined supply pressure to the first resin 38x and the second resin 39x. The control device 10 also drives and controls the take-up device 24 to start conveying the long core material 100. At the same time, the take-up device 24 drives and controls the winding drum 25 to start winding the long flexible tube 102.

[0085] The action of the take-up machine 24 is as follows: Under the control of the control device 10, the take-up machine 24 transports the long flexible tube 102 in a predetermined direction T (the direction toward the winding drum 25) at a predetermined speed.

[0086] To this end, the take-up machine 24 drives the pressure cylinder 24c to move the upper belt 24a under the control of the control device 10. As a result, the long flexible tube 102 is sandwiched between the upper belt 24a and the lower belt 24b with an appropriate pressure.

[0087] In this state, the control device 10 drives the rotation drive mechanism (not shown) of the take-up machine 24 at a predetermined rotation speed. This drives the upper belt 24a and the lower belt 24b. Therefore, the long flexible tube 102 is transported in a predetermined horizontal direction. At the same time, the take-up machine 24 drives and controls the winding drum 25. As a result, the long flexible tube 102 transported from the take-up machine 24 is wound onto the winding drum 25.

[0088] In this manner, the long flexible tube 102 passes through the interior of the take-up machine 24 (see FIG. 5). At this time, the outer diameter of the portion of the long flexible tube 102 that connects the flexible tubes (102), i.e., the portion of the connecting dummy tube 101, is smaller than the outer diameter of each flexible tube (102), as shown in FIG. 5 etc.

[0089] In a conventional take-off machine, the pressure applied to the long flexible tube by the pressure cylinder is adjusted only by the upper belt.

[0090] As a result, a constant pressure is constantly applied to the long flexible tube during transport. This long flexible tube is composed of flexible tube sections and connecting dummy tubes alternately connected, and the outer diameter of the flexible tube sections is larger than that of the connecting dummy tubes. Therefore, when a constant pressure is applied to the long flexible tube, stress may be concentrated in the flexible tube sections, causing them to collapse. Furthermore, when the upper and lower belts rotate, there is a problem of slippage if the distance between the flexible tube sections is short.

[0091] Taking this into consideration, conventional take-off machines operate the pressure cylinder to adjust the pressure to match the outer diameter of the connecting dummy tube. This allows the transport of the long flexible tube to continue. When the next section of flexible tube is transported with the connecting dummy tube between the upper and lower belts, the pressure from the pressure cylinder is too strong and excessive pressure is applied to the flexible tube. Therefore, in this case, the pressure cylinder is operated to adjust the pressure to match the outer diameter of the flexible tube.

[0092] In such a conventional take-up machine, the pressure is adjusted by raising and lowering the pressure cylinder as a whole. Therefore, when the transition between the flexible tube portion and the connecting portion occurs immediately after the flexible tube portion enters the take-up machine or immediately before the flexible tube portion leaves the take-up machine, the area where the upper and lower belts come into contact with the outer periphery of the flexible tube portion or the connecting portion becomes small, which causes a problem in that the long flexible tube cannot be transported stably.

[0093] Therefore, in the take-up machine 24 of the flexible tube manufacturing apparatus 1 of this embodiment, as described above, the pressure cylinder 24c has a configuration that individually drives the multiple cylinders 24d. With this configuration, a constant pressure is always applied to the pressure cylinder 24c, and when both the long flexible tube 102 and the connecting dummy tube 101 are inside the take-up machine 24 during transport of the long flexible tube 102, the multiple cylinders 24d are retracted vertically, and the upper belt comes into close contact with both the flexible tube and the dummy tube.

[0094] In this case, at the transition portion between the flexible tube portion and the connecting portion, as shown in Fig. 7, the two rollers 24db are arranged by a link mechanism so as to always follow the outer peripheries of the flexible tube portion and the connecting portion, thereby always applying appropriate pressure. With this configuration, the take-up machine 24 in this embodiment can always transport the long flexible tube 102 smoothly and stably at a predetermined pressure and a predetermined speed. At the same time, the pressure applied to the long flexible tube 102 can always be maintained at an appropriate level. Therefore, excessive pressure is not applied to the long flexible tube 102. Furthermore, there is no risk of the pressure applied to the long flexible tube 102 being insufficient, making it impossible to transport.

[0095] Due to this action, in the flexible tube manufacturing apparatus 1 of this embodiment, when the take-up machine 24 starts transporting the long flexible tube 102, the first resin supply machine 38 simultaneously supplies the first resin 38x to the first flow path 41. In addition, the second resin supply machine 39 supplies the second resin 39x to the second flow path 42. At this time, the inner layer mandrel 31 is rotating in the circumferential direction of the core material.

[0096] Therefore, the first resin 38x supplied to the first flow path 41 is uniformly dispersed in a predetermined circumferential direction. At the same time, the spiral groove 31e of the inner layer mandrel 31 acts to push the first resin 38x supplied to the first flow path 41 forward (toward the tip end) toward the die outlet. This allows the first resin 38x to flow smoothly through the first flow path 41 toward the tip end along the outer periphery of the inner layer mandrel 31. At the same time, the second resin 39x supplied to the second flow path 42 flows toward the tip end along the spiral groove 32e of the outer layer mandrel 32.

[0097] Thus, the first resin 38x flowing through the first flow path 41 and the second resin 39x flowing through the second flow path 42 form two layers in the confluence flow path 43. After that, the resin obtained after the first resin 38x and the second resin 39x are joined is applied to the outer periphery of the elongated core material 100 from the confluence flow path 43 on the outer periphery side of the tip of the inner layer nozzle 34. At this time, the inner layer mandrel 31 is rotating in the circumferential direction of the core material. Therefore, the two types of resins after joining are applied to the outer periphery of the elongated core material 100 while rotating in the circumferential direction of the core material.

[0098] At this time, for example, suppose that the first resin 38x stagnates in the first flow path 41. In such a case, the pressure at the tip end of the first flow path 41 increases. As a result, the first resin 38x in the first flow path 41 may flow back through the first flow path 41. At this time, the first resin 38x flowing back through the first flow path 41 does not enter the inside of the first resin supply device 38 from the first supply port 38a, but flows out toward the spiral groove 31e provided in the region 31cb of the spiral groove 31e of the inner layer mandrel 31.

[0099] Here, the reason why the backflow resin does not enter the first supply port 38a is as follows.

[0100] The first resin supply device 38 is constantly applied with pressure toward the outside (first flow path 41 side) to supply the first resin 38x from the first supply port 38a. Therefore, the backflow resin flows toward the spiral groove 31e side of the region 31cb where the pressure is lowest.

[0101] In this way, the long flexible tube 102, in which the outer periphery of the long core material 100 is coated with resin, passes through the through hole 36b of the die 36. As a result, the resin coating on the outer periphery of the long flexible tube 102 is adjusted to a specified wall thickness. Thereafter, the resin-coated long flexible tube 102 is sent out from the resin coating device 11.

[0102] In this way, the long core material 100 is coated with resin on its outer periphery by passing through the resin coating device 11. The resin coated on the outer periphery of the long flexible tube 102 is adjusted to a specified wall thickness by inserting the long flexible tube 102 through the through hole 36b of the die 36. The resin-coated long flexible tube 102 is then transported from the resin coating device 11 to the outside.

[0103] Next, the long flexible tube 102 enters the cooling device 12. As a result, the resin coating the outer periphery of the long flexible tube 102 is solidified while passing through the cooling device 12. Thereafter, the long flexible tube 102 is transported from the cooling device 12 to the outside.

[0104] After passing through the cooling device 12, the long flexible tube 102 enters the next take-up device 23. After entering the take-up device 23, the long flexible tube 102 first enters a take-up machine 24. In this take-up machine 24, a conveying force is applied to the long flexible tube 102. Next, after passing through the take-up machine 24, the long flexible tube 102 is wound onto a winding drum 25.

[0105] As described above, according to the first embodiment, in the flexible tube manufacturing apparatus 1 that coats the outer periphery of the core material of a flexible tube with resin, the first flow path 41 and the second flow path 42 are formed separately up to the vicinity of the die 36, so that the volume of the confluence flow path 43 through which the first resin 38x and the second resin 39x flow after they merge to form the annular two-layer can be reduced. Therefore, it is possible to mold flexible tubes with abrupt changes in flexibility. Note that the configuration of the present invention can accommodate not only abrupt changes but also gradual shape changes.

[0106] Furthermore, by rotating the inner layer mandrel 31 in the circumferential direction of the core material, the first resin 38x flowing around the inner layer mandrel 31 and the outer periphery of the inner layer nozzle 34 is uniformly dispersed in the circumferential direction and extruded toward the die outlet. This allows the first resin 38x to always flow smoothly and stably through the first flow path 41. This allows the first resin 38x to be applied to the outer periphery of the core material in a generally uniform and stable manner. At the same time, even if the supply rate of the first resin 38x is suddenly reduced, the rotation of the inner layer mandrel 31 and the inner layer nozzle 34 extrudes the first resin 38x toward the die outlet, preventing any areas of the core material from being left uncoated with resin.

[0107] In addition, as a countermeasure for the case where the first resin 38x backflows within the first flow passage 41 due to an increase in pressure at the distal end of the first flow passage 41 caused by stagnation of the first resin 38x in the first flow passage 41 caused by rotating the inner layer mandrel 31 in the circumferential direction of the core material, the spiral groove 31e of the inner layer mandrel 31 is extended to the region 31cb near the rear end of the distal region 31c. This allows the backflowing first resin 38x to retreat to the extended portion near the rear end of the spiral groove 31e, thereby eliminating the pressure difference between the distal and proximal ends of the first flow passage 41. This prevents the occurrence of areas on the core material surface that are not covered with resin due to the backflow of the first resin 38x. This allows for rapid adjustment of flexibility.

[0108] On the other hand, by providing spiral groove 32e on the outer periphery of outer layer mandrel 32, it is possible to provide the second resin 39x with the effect of dispersing it uniformly in the circumferential direction. Furthermore, by providing spiral groove 32e, it is possible to cause second resin 39x supplied from second supply port 39a to flow uniformly in the circumferential direction toward one location on the outer periphery of outer layer mandrel 32. This allows second resin 39x to be layered on first resin 38x to form an annular two-layer structure, and also allows two layers of resin to be applied uniformly in the circumferential direction of the core material.

[0109] In this way, without complicating the configuration, the simple configuration of rotating the inner layer mandrel 31 prevents the creation of areas on the core material surface that are not coated with resin, makes it possible to mold flexible tubes with sudden changes in flexibility, and makes the thickness of the resin coated around the circumferential direction of the core material of the flexible tube approximately uniform, thereby realizing a flexible tube manufacturing device that can manufacture flexible tubes stably and at low cost.

[0110] In the first embodiment described above, the drive unit 37 is configured to rotate only the inner layer mandrel 31. Furthermore, if the inner layer mandrel 31 and the inner layer nozzle 34 are configured as an integrated unit, the inner layer mandrel 31 and the inner layer nozzle 34 can be rotated simultaneously. In this manner, when the inner layer mandrel 31 and the inner layer nozzle 34 are configured to rotate simultaneously, this can contribute to suppressing uneven application of resin to the outer periphery of the core material compared to when only the inner layer mandrel 31 is rotated.

[0111] Furthermore, in the first embodiment described above, a configuration example was shown in which spiral grooves 31e, 32e were provided on the outer peripheries of the inner layer mandrel 31 and the outer layer mandrel 32, but this configuration example is not limited to this. For example, in addition to the spiral grooves 31e, 32e on the inner layer mandrel 31 and the outer layer mandrel 32, similar spiral grooves may also be provided on the outer peripheries of the inner layer nozzle 34 and the outer layer nozzle 35. In this case, various combinations are possible, such as a configuration in which a spiral groove is provided on either the inner layer nozzle 34 or the outer layer nozzle 35, or a configuration in which a spiral groove is provided on both the inner layer nozzle 34 and the outer layer nozzle 35.

[0112] [Modification of the first embodiment] In the first embodiment described above, as shown in Figure 2, the tip position of the inner layer nozzle 34 (see symbol [A1] in Figure 2) is positioned closer to the tip side than the tip position of the outer layer nozzle 35 (see symbol [B1] in Figure 2). However, the tip positions of the inner layer nozzle 34 and the outer layer nozzle 35 are not limited to the configuration example of the first embodiment described above.

[0113] For example, Fig. 8 is an enlarged view of a main part showing a modification of the first embodiment of the present invention. In this modification shown in Fig. 8, the tip position of the inner layer nozzle 34A (see symbol [A2] in Fig. 8) is positioned closer to the base end than the tip position of the outer layer nozzle 35A (see symbol [B2] in Fig. 8).

[0114] In the configuration of this modified example, the first resin 38x and the second resin 39x do not merge, and the first resin 38x is first applied from the first flow path 41 to the outer periphery of the core material (not shown in FIG. 8). Thereafter, the second resin 39x is applied from the second flow path 42 to the outer periphery of the core material. Therefore, in this configuration, the first resin 38x and the second resin 39x are each laminated to coat the outer periphery of the core material.

[0115] Although not shown in the figures, another variation of the configuration is also possible in which the tip of the inner layer nozzle and the tip of the outer layer nozzle are positioned at approximately the same position. In this configuration, the order in which the outer periphery of the core material is coated with the first resin from the first flow path and the second resin from the second flow path varies depending on the type, hardness, and viscosity of the applied resin. Therefore, by appropriately selecting the first resin and the second resin, it is possible to determine the resin that coats the inside of the core material and the resin that coats the outside of that.

[0116] In this way, even if the configuration of each of the above-mentioned modified examples, i.e., the arrangement of the tip positions of the inner layer nozzle and the outer layer nozzle, is changed, it is possible to obtain effects substantially similar to those of the first embodiment described above, and it is possible to configure the coating configuration of the flexible tube to be set to the desired form.

[0117] Furthermore, when the configuration of the first embodiment shown in Figure 2 above is used, i.e., when the tip position [A1] of the inner layer nozzle 34 is positioned closer to the tip side than the tip position [B1] of the outer layer nozzle 35, further effects can be expected, as follows.

[0118] That is, in the configuration of the first embodiment described above, the outer layer nozzle 35 merges the second resin 39x with the rotating first resin 38x, and guides the second resin 39x to the outer periphery of the outer layer nozzle 35, and guides the first resin 38x to the inside thereof. This allows the resins applied to the outer periphery of the core material to be applied in two layers while merging, contributing to uniform thickness.

[0119] [Second embodiment] In the first embodiment described above, a configuration in which only the inner layer mandrel 31 is rotated, or a configuration in which the integrated inner layer mandrel 31 and the inner layer nozzle 34 are simultaneously rotated, is exemplified. However, the target member rotated in the circumferential direction of the core material by the drive unit 37 is not limited to these configuration examples.

[0120] The drive unit may be configured to rotate at least one of the inner layer mandrel and the outer layer mandrel. Therefore, in addition to the configuration example of the first embodiment described above, for example, a configuration in which only the outer layer mandrel is rotated by the drive unit may also be used. Also, a configuration in which both the inner layer mandrel and the outer layer mandrel are rotated by the drive unit may be used. The second embodiment of the present invention described next is an example of a configuration in which both the inner layer mandrel and the outer layer mandrel are rotated.

[0121] 9 and 10 are diagrams showing a second embodiment of the present invention. Of these, Fig. 9 is a cross-sectional view simply showing the configuration of a resin coating device in a flexible tube manufacturing apparatus of this embodiment. Fig. 10 is a schematic perspective view showing only the second cylindrical member (outer layer mandrel) extracted from the resin coating device of Fig. 9.

[0122] The configuration of the flexible tube manufacturing apparatus of this embodiment is basically substantially the same as that of the first embodiment. In this embodiment, the only difference is the configuration of the outer layer mandrel 32B, which is the second cylindrical member in the resin coating device 11B, and the drive unit 37B. Therefore, in describing the configuration of this embodiment, the same components as those in the first embodiment are given the same reference numerals and their description is omitted. Only the parts that are different from the first embodiment will be described in detail below.

[0123] In the first embodiment described above, a configuration example is shown in which the drive unit 37 rotates only the inner layer mandrel 31, or rotates the inner layer mandrel 31 and the inner layer nozzle 34 together. In this embodiment, in addition to the configuration of the first embodiment described above, the outer layer mandrel 32B is also rotated. The configuration for this is as follows.

[0124] 10, the outer layer mandrel 32B in the resin coating apparatus 11B of this embodiment is formed with a tubular portion 32m having openings 32a, 32b at the front end (one end) and rear end (the other end) and formed into a generally cylindrical shape as a whole, and a driven portion 32n provided on the rear end side of the tubular portion 32m and connected to the drive unit 37B. The configuration in which the inner layer mandrel 31 is rotatably inserted inside the outer layer mandrel 32B is the same as in the first embodiment described above.

[0125] The driven portion 32n of the outer layer mandrel 32B is formed with a cylindrical flange portion 32Bh and a driven gear 32o. The cylindrical flange portion 32Bh is formed by extending the flange portion 32h of the outer layer mandrel 32 in the first embodiment described above toward the rear end in a direction along the central axis of the outer layer mandrel 32B.

[0126] The driven gear 32o is a member that receives a rotational driving force from a second drive motor 37d of the drive unit 37B (described later) and rotates the outer layer mandrel 32B. The driven gear 32o is fixed to the outer periphery of the cylindrical flange portion 32Bh coaxially with the cylindrical flange portion 32Bh.

[0127] The outer layer mandrel 32B has the outer periphery of the cylindrical flange portion 32Bh rotatably supported by a bearing member 37f, as shown in Figure 9. A drive unit 37B is connected to the driven gear 32o of the driven portion 32n of the outer layer mandrel 32B.

[0128] Here, the drive unit 37B of this embodiment is a structural unit that rotates the inner layer mandrel 31 and the outer layer mandrel 32B in a direction along the circumferential direction of the core material 100. The drive unit 37B is configured to include a second drive motor 37d and a second drive force transmission mechanism 37e in addition to the configuration of the drive unit 37 of the first embodiment described above (drive motor 37a, drive force transmission mechanism 37b).

[0129] Here, the second drive motor 37d is a drive source that generates a rotational drive force for rotating the outer layer mandrel 32B. The second drive force transmission mechanism 37e is a mechanism that transmits the rotational drive force of the drive motor 37d to the outer layer mandrel 32B. As an example of the second drive force transmission mechanism 37e, FIG. 9 illustrates a gear-driven drive force transmission mechanism that is configured with a drive gear coaxially fixed to the drive shaft of the second drive motor 37d and a driven gear 32o that meshes with the drive gear. Note that the configuration of the second drive force transmission mechanism 37e is not limited to the example shown in FIG. 9 and may be configured in other ways. For example, as another configuration example of the second drive force transmission mechanism 37e, a belt drive system similar to that of the drive transmission mechanism 37b that rotates the inner layer mandrel 31 may be adopted.

[0130] On the other hand, the cylindrical portion 32m of the outer layer mandrel 32B has a spiral groove 32e formed on the outer periphery of the tip region 32c, which is the same as in the first embodiment.

[0131] As described above, the outer layer mandrel 32B in this embodiment is configured to be rotatable by the drive unit 37B. Therefore, as shown in Fig. 10, the outer layer mandrel 32B in this embodiment is configured to have a first circumferential groove 32p and a second circumferential groove 32q on the outer periphery of the rear end region 32d.

[0132] The first circumferential groove 32p is formed in a portion of the outer periphery of the outer layer mandrel 32B that corresponds to the first supply port 38a and where the through hole 32k is provided. With this configuration, the first resin 38x supplied from the first supply port 38a first flows into the first circumferential groove 32p on the outer periphery of the rotating outer layer mandrel 32B. The first resin 38x that has flowed into the first circumferential groove 32p flows through the through hole 32k into the first flow path 41 on the outer periphery of the inner layer mandrel 31.

[0133] Meanwhile, the second circumferential groove 32q is formed in a portion of the outer periphery of the outer layer mandrel 32B corresponding to the second supply port 39a. With this configuration, the second resin 39x supplied from the second supply port 39a flows into the second circumferential groove 32q on the outer periphery of the rotating outer layer mandrel 32B. The second resin 39x that has flowed into the second circumferential groove 32q flows from the supply point 32f into the spiral groove 32e and eventually into the second flow path 42. Note that the spiral groove 32e is configured, for example, as a single spiral groove provided around the entire outer periphery, similar to the inner layer mandrel 31 (see FIG. 3). The other configurations are the same as those of the first embodiment described above.

[0134] In this embodiment, the inner layer mandrel 31 and the outer layer mandrel 32B are configured to rotate. Therefore, the drive unit 37B needs to appropriately control the rotation speed and rotation direction of each of the inner layer mandrel 31 and the outer layer mandrel 32B in a predetermined manner.

[0135] For example, the first resin 38x and the second resin 39x may be different in hardness, viscosity, or type. In this case, the flow speed also differs depending on the characteristics of the applied resin. Taking this into consideration, the rotation speed is controlled so as to provide an appropriate extrusion action toward the die outlet depending on the hardness, viscosity, or type of the applied resin.

[0136] For example, depending on the characteristics of the resins being used, the inner layer mandrel 31 and the outer layer mandrel 32B may be rotated at the same rotational speed. However, if the inner layer mandrel 31 and the outer layer mandrel 32B are rotated at the same rotational speed and in the same direction, both mandrels 31 and 32B are essentially not rotating. In this case, the effects of uniformly dispersing the second resin 39x flowing through the second flow passage 42 around the outer layer mandrel 32B in the circumferential direction and extruding it toward the die exit are achieved. However, the effects of uniformly dispersing the first resin 38x flowing through the first flow passage 41 between the mandrels 31 and 32B in the circumferential direction and extruding it toward the die exit are reduced. Therefore, in a configuration in which the inner layer mandrel 31 and the outer layer mandrel 32B are rotated, when both mandrels 31 and 32B are rotated in the same direction, it is preferable to control the rotations so that there is a difference in rotational speed between them.

[0137] The rotation directions of the inner layer mandrel 31 and the outer layer mandrel 32B do not necessarily have to be the same. Therefore, the inner layer mandrel 31 and the outer layer mandrel 32B may be controlled to rotate in the same direction, or may be controlled to rotate in different directions.

[0138] Furthermore, the helical shape of helical groove 31e of inner layer mandrel 31 and the helical shape of helical groove 32e of outer layer mandrel 32B do not need to be the same shape, and may be different shapes depending on the properties of the resin to be used. For example, the groove pitch of each helical groove 31e, 32e may be different from each other.

[0139] As described above, in the second embodiment, the outer layer mandrel 32B is rotated in addition to the inner layer mandrel 31. This configuration can achieve the same effects as the first embodiment. Furthermore, this embodiment can provide the effect of uniformly dispersing the first resin 38x flowing through the first flow passage 41 between the inner layer mandrel 31 and the outer layer mandrel 32B, as well as the effect of extruding the second resin 39x flowing through the second flow passage 42 on the outer periphery of the outer layer mandrel 32B, in the circumferential direction and toward the die outlet. Therefore, the configuration of this embodiment can contribute to uniformly distributing the resin in the circumferential direction when applying the resin to the outer periphery of the core material (100).

[0140] In the second embodiment described above, the spiral groove 32e of the outer layer mandrel 32B is provided only on the outer periphery of the tip region 32c, but this is not limitative. For example, similar to the inner layer mandrel 31, the spiral groove 32e may be extended to the region between the second circumferential groove 32q and the first circumferential groove 32p (through hole 32k) on the outer periphery of the rear end region 32d of the outer layer mandrel 32B, which is closer to the rear end than the supply point 32f.

[0141] According to this configuration, the rotation of the outer layer mandrel 32B smooths the flow of resin within the second flow passage 42. As a result, if the pressure within the second flow passage 42 increases due to stagnation of the second resin 39x within the second flow passage 42, causing the second resin 39x to flow backward through the second flow passage 42, the backward-flowing second resin 39x can be evacuated toward the rear end of the spiral groove 32e. This eliminates the pressure difference between the distal end and proximal end within the second flow passage 42. Furthermore, it is possible to prevent the occurrence of areas on the core material surface that are not covered with resin due to the backward flow of the second resin 39x.

[0142] [Modification of the second embodiment] The second embodiment described above shows an example of a configuration in which the inner layer mandrel 31 and the outer layer mandrel 32B are rotated in the circumferential direction of the core material by the drive unit 37B. Here, a modification of the configuration of the second embodiment described above can be considered in which the drive motor 37a and the drive force transmission mechanism 37b included in the drive unit 37B are removed (note that even if the drive motor 37a and the like are not removed, the same effect can be obtained by, for example, controlling the drive motor 37a so that it does not rotate).

[0143] In a modified example having such a configuration, the inner layer mandrel 31 is non-rotating, and only the outer layer mandrel 32B is rotated by the drive unit 37B. When only the outer layer mandrel 32B is rotated in this manner, a spiral groove 32e is provided on the outer periphery of the outer layer mandrel 32B, and a similar spiral groove may also be formed on the inner periphery of the outer layer mandrel 32B. When this configuration is adopted, the inner layer mandrel 31 can be formed without the spiral groove 31e on the outer periphery.

[0144] According to this modification, the configuration can be simplified, which can contribute to reducing manufacturing costs.

[0145] Furthermore, in the configuration shown in the above modified example, another modified example is also conceivable in which the outer layer mandrel 32B and the outer layer nozzle 35 are integrally connected. By adopting such a configuration, in this modified example, the outer layer nozzle 35 can be simultaneously rotated in the same direction by rotating the outer layer mandrel 32B.

[0146] Therefore, according to the configuration of the above-mentioned other modified example, by simply making a configuration change to the configuration of the above-mentioned modified example, it is possible to contribute to making the resin more uniform in the circumferential direction when applying the resin to the outer periphery of the core material (100).

[0147] Furthermore, in the configuration of the second embodiment described above, the inner layer mandrel 31 and the inner layer nozzle 34 may be integrally connected, and the outer layer mandrel 32B and the outer layer nozzle 35 may be integrally connected.

[0148] In such a configuration, the drive unit 37B can be configured to rotate the inner layer mandrel 31 and the outer layer mandrel 32B, thereby simultaneously rotating both the mandrels (31, 32B) and both the nozzles (34, 35).

[0149] In this way, when both mandrels (31, 32B) and both nozzles (34, 35) are configured to rotate, it is possible to contribute to further uniformity of the resin in the circumferential direction when applying the resin to the outer periphery of the core material (100).

[0150] [Third embodiment] On the other hand, each of the above-mentioned embodiments shows various configuration examples in which one or both of the inner layer mandrel and the outer layer mandrel, or one or both of the inner layer mandrel and the inner layer nozzle and the outer layer mandrel and the outer layer nozzle, are rotated in various combinations by a drive unit.

[0151] However, the present invention is not limited to these configuration examples, and various configurations are also possible, such as rotating only the inner layer nozzle, only the outer layer nozzle, or both the inner layer nozzle and the outer layer nozzle.

[0152] Therefore, in the third embodiment of the present invention described below, a configuration in which only the inner layer nozzle is rotated is exemplified. Figures 11 to 13 are views showing the third embodiment of the present invention. Of these, Figure 11 is a cross-sectional view showing a simplified configuration of a resin coating device in a flexible tube manufacturing apparatus of this embodiment. Figure 12 is a schematic perspective view showing only the rotating shaft for rotating the first nozzle (inner layer nozzle) in the resin coating device of Figure 11. Figure 13 is a schematic perspective view showing only the first tubular member (inner layer mandrel) in the resin coating device of Figure 11.

[0153] The configuration of the flexible tube manufacturing apparatus of this embodiment is basically similar to that of the first embodiment. The difference in this embodiment is that the resin coating device 11C further includes a rotating shaft 44 that rotates only the inner layer nozzle 34C. In accordance with this change in configuration, the configurations of the inner layer mandrel 31C, which is the first cylindrical member, and the drive unit 37C are different. Therefore, in describing the configuration of this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description is omitted. Only the parts that differ from the first embodiment will be described in detail below.

[0154] In this embodiment, as described above, only the inner layer nozzle 34C is rotated. The configuration for this purpose is as follows.

[0155] As shown in FIG. 11, the resin coating apparatus 11C of this embodiment further includes a rotary shaft 44 that is connected to the inner layer nozzle 34C and rotates the inner layer nozzle 34C.

[0156] As shown in Fig. 12, the rotating shaft 44 has openings 44a, 44b at its front end (one end) and rear end (the other end), and is formed into a generally cylindrical shape overall. A core (100) is inserted into the rotating shaft 44 (see Fig. 11). The rotating shaft 44 is formed with a helical groove 44e, which is a helical circumferential groove, on the outer periphery of the front end region 44c. The helical groove 44e is formed within a predetermined range on the front end side of the outer periphery of the front end region 44c of the rotating shaft 44. The helical groove 44e is formed to prevent the pressure on the front end side of the first flow path 41 from exceeding a certain pressure.

[0157] For example, if the flow of the first resin 38x stagnates in the tip end portion of the first flow path 41, and the pressure at the tip end side in the first flow path 41 increases, the first resin 38x may flow back through the first flow path 41 toward the first supply port 38a. Therefore, by forming the spiral groove 44e in the rotating shaft 44, the spiral groove 44e becomes a space to which the first resin 38x that may flow back through the first flow path 41 for the above-mentioned reason can escape.

[0158] The outer periphery of the rear end region 44d of the rotating shaft 44 is rotatably supported by a bearing member 37c (see FIG. 11). As shown in FIG. 11, a drive unit 37C that rotates the rotating shaft 44 is connected to the rear end region 44d of the rotating shaft 44. In this case, the connection between the rotating shaft 44 and the drive unit 37C is configured substantially similarly to the connection between the rear end region 31d of the inner layer mandrel 31 and the drive unit 37 in the first embodiment described above. An inner layer nozzle 34C is integrally connected to the tip of the rotating shaft 44.

[0159] On the other hand, in the resin coating device 11C of this embodiment, the inner layer mandrel 31C is a component through which the rotating shaft 44 is rotatably inserted, and which supplies the first resin 38x supplied to the outer periphery to the outer periphery of the inner layer nozzle 34C by dispersing it uniformly in the circumferential direction and by pushing it toward the die outlet. The inner layer mandrel 31C is basically configured in a manner similar to that of the first embodiment described above.

[0160] As shown in Figure 13, the inner layer mandrel 31C in this embodiment has openings 31a and 31b at its front (one end) and rear (other end) ends, and is formed into a generally cylindrical shape overall. This inner layer mandrel 31C is formed with a spiral groove 31e on its outer periphery. This spiral groove 31e is formed in a predetermined region on the front side of the outer periphery of the inner layer mandrel 31C. Specifically, the spiral groove 31e is formed in a region on the front side of a supply point 31f where a first resin 38x is supplied to the outer periphery of the inner layer mandrel 31C.

[0161] In this embodiment, the spiral groove 31e of the inner layer mandrel 31C is formed only in a region closer to the tip end than the supply point 31f. That is, in this embodiment, the spiral groove 44e is provided in the rotating shaft 44 to accommodate the backflow of resin from the first flow path 41. For this reason, in the configuration of this embodiment, the spiral groove 31e is omitted from the rear end region of the inner layer mandrel 31C.

[0162] Additionally, the inner layer mandrel 31C has a flange portion 31h formed at its rear end. This flange portion 31h is provided to fix the inner layer mandrel 31C to the flange portion 32h (see FIGS. 11 and 4) of the outer layer mandrel 32. The other configurations are the same as those of the first embodiment described above.

[0163] The third embodiment configured as described above can achieve substantially the same effects as the first embodiment. Furthermore, according to this embodiment, the spiral groove 44e is provided on the rotating shaft 44, which simplifies the configuration of the inner layer mandrel 31C.

[0164] In the third embodiment described above, an example of a configuration in which only the inner layer nozzle 34C is rotated is shown, but other than this configuration, for example, a configuration in which only the outer layer nozzle is rotated may also be used, or a configuration in which both the inner layer nozzle and the outer layer nozzle are rotated may also be used.

[0165] The present invention is not limited to the above-described embodiments, and various modifications and applications can be made without departing from the spirit and scope of the invention. Furthermore, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed multiple constituent elements. For example, if the problem to be solved by the invention can be solved and the effects of the invention can be obtained even if some constituent elements are deleted from all the constituent elements shown in each of the above embodiments, the configuration from which these constituent elements are deleted can be extracted as the invention. Furthermore, constituent elements from different embodiments may be appropriately combined. The present invention is not limited by specific embodiments other than as limited by the appended claims. [Explanation of symbols]

[0166] 1...Flexible tube manufacturing equipment 10...Control device 11, 11B, 11C...Resin coating device 12…Cooling device 13...Transportation device 21…Feeding device 22...Supply drum 23...Removal device 24...Pick-up machine 25...winding drum 31, 32B, 31C...Inner layer mandrel 31e,32e,44e...Spiral groove 32, 32B...Outer mandrel 33...Hollow member 34, 34A, 34C...Inner layer nozzle 35, 35A...Outer layer nozzle 36...Dice 36a...Engagement part 36b...Through hole 37, 37B, 37C...Drive unit 38...First resin 38a...First supply port 38x...First resin 39a...Second supply port 39x...Second resin 40...Heating device 41...First flow path 42...Second flow path 43...Confluence channel 44...Rotating shaft 100...Long core material 101...Connected dummy tube 102...Long flexible tube

Claims

1. A flexible tube manufacturing apparatus for coating a resin on an outer periphery of a core material of a flexible tube, comprising: a first cylindrical member into which the core material is inserted and which has a first spiral groove on the outer periphery; a second cylindrical member into which the first cylindrical member is inserted, the second cylindrical member having a second spiral groove on the outer periphery and forming a first flow path between the first cylindrical member and the second cylindrical member; a hollow member into which the second cylindrical member is inserted, forming a second flow path between the hollow member and the second cylindrical member; a first nozzle connected to one end of the first cylindrical member; a second nozzle connected to one end of the second cylindrical member and merging the first flow path and the second flow path; a drive unit that rotates at least one of the first cylindrical member, the first nozzle, the second cylindrical member, and the second nozzle in a circumferential direction of the core material; A flexible tube manufacturing apparatus comprising:

2. a first supply port that supplies a first resin to the first flow path; a second supply port that supplies a second resin to the second flow path; 2. The flexible tube manufacturing apparatus according to claim 1, further comprising:

3. The first resin and the second resin have different hardness or viscosity.

3. The flexible tube manufacturing apparatus according to claim 2.

4. The first resin and the second resin are different in type from each other.

3. The flexible tube manufacturing apparatus according to claim 2.

5. The drive unit rotates either or both of the first cylindrical member and the second cylindrical member.

2. The flexible tube manufacturing apparatus according to claim 1.

6. The drive unit rotates either or both of the first nozzle and the second nozzle.

2. The flexible tube manufacturing apparatus according to claim 1.

7. The drive unit rotates the first cylindrical member and the first nozzle.

2. The flexible tube manufacturing apparatus according to claim 1.

8. The drive unit rotates the second cylindrical member and the second nozzle.

2. The flexible tube manufacturing apparatus according to claim 1.

9. a side of the first nozzle that is not connected to the first cylindrical member is defined as a tip side; The first cylindrical member and the first nozzle have a tapered shape in which the outer diameter of the tip side becomes smaller.

2. The flexible tube manufacturing apparatus according to claim 1.

10. a side of the second nozzle that is not connected to the second cylindrical member is defined as a tip side; The second cylindrical member and the second nozzle have a tapered shape in which the outer diameter on the second nozzle side becomes smaller.

2. The flexible tube manufacturing apparatus according to claim 1.

11. Further, the die is provided on the outer periphery of the second nozzle, The die is an engaging portion having an inner surface formed in a shape that follows the outer periphery of the one end of the second nozzle; a through hole into which the core material is inserted after being coated with a resin; 2. The flexible tube manufacturing apparatus according to claim 1, further comprising:

12. a shaft connected to the first nozzle or the second nozzle and rotating the first nozzle or the second nozzle; The shaft has a groove on the outer circumferential surface.

7. The flexible tube manufacturing apparatus according to claim 6.

13. The heating device further includes a heating device for heating at least one of the first cylindrical member, the second cylindrical member, and the hollow member.

2. The flexible tube manufacturing apparatus according to claim 1.

14. The first groove and the second groove have different shapes or groove pitches.

2. The flexible tube manufacturing apparatus according to claim 1.

15. The first groove and the second groove are configured in a form that branches from a single spiral shape into multiple spiral grooves.

2. The flexible tube manufacturing apparatus according to claim 1.

16. A spiral groove is provided on at least one of the outer periphery of the first nozzle and the outer periphery of the second nozzle.

2. The flexible tube manufacturing apparatus according to claim 1.

17. A method for manufacturing a flexible tube in which a resin is coated on an outer periphery of a core material of the flexible tube, supplying a first resin to a first flow path provided along an outer periphery of the core material; A second resin is supplied to a second flow path provided outside the first flow path and along an outer periphery of the core material; At least one of the first flow path, the second flow path, and a joining flow path provided at a tip of the first flow path and the second flow path is rotated in a circumferential direction of the core material, The first resin that has passed through a spiral first groove provided in the first flow path and the second resin that has passed through a spiral second groove provided in the second flow path are applied to the outer periphery of the core material by the confluent flow path. A method for manufacturing a flexible tube.

18. one of the first resin and the second resin rotates in a circumferential direction of the core material, The other of the first resin and the second resin is rotated in the circumferential direction by merging with the one of the resins in the merging flow path.

18. The method for manufacturing a flexible tube according to claim 17.

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