Apparatus for manufacturing hollow cylindrical molded products and method for manufacturing hollow cylindrical molded products

Abstract

To provide a manufacturing apparatus for a hollow cylindrical molded product and a method for manufacturing a hollow cylindrical molded product that can more appropriately demold the hollow cylindrical molded product from a core mold.SOLUTION: A manufacturing apparatus 20 for manufacturing a hollow cylindrical molded product 10 formed in a hollow cylindrical shape, having an inner shape part 15 which is a concavity 14b1 and / or a protrusion 14b2 on an inner wall 14b, and made of an elastic material includes: a core mold 32 having an inner shape part forming part 34b that forms the inner shape part 15 of the hollow cylindrical molded product 10; an injection device 50 that injects gas between the hollow cylindrical molded product 10 and the core mold 32 when removing the hollow cylindrical molded product 10 from the core mold 32; and hollow cylindrical guide 60 arranged to at least cover the inner shape part forming part 34b when injecting gas with the injection device 50.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0006] , , ,

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[0001] The present invention relates to an apparatus for manufacturing a hollow cylindrical molded product and a method for manufacturing a hollow cylindrical molded product.

Background Art

[0002] As an apparatus for manufacturing a hollow cylindrical molded product, Patent Document 1 discloses an injection molding die for a resin hose having a bellows portion that forms an undercut. After forming a thermoplastic elastomer by injection molding into a cavity formed by a cavity die that forms the outer surface of the hose and a core die that forms the inner surface of the hose, the diameter of the bellows portion is expanded and pulled out from the core die for demolding. In this injection molding die, the undercut bellows portion is inflated by an air injector or the like to expand the diameter and forcefully removed from the core die.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide an apparatus for manufacturing a hollow cylindrical molded product and a method for manufacturing a hollow cylindrical molded product that can more appropriately demold the hollow cylindrical molded product from the core die.

Means for Solving the Problems

[0006] To solve the above problems, the present invention provides a manufacturing apparatus for hollow cylindrical molded articles, which is formed in a hollow cylindrical shape and has an inner shape portion having a recess and / or convex portion on its inner wall, and is made of an elastic material, comprising: a core mold having an inner shape portion forming portion for forming the inner shape portion of the hollow cylindrical molded article; an injection device for injecting gas between the hollow cylindrical molded article and the core mold when removing the hollow cylindrical molded article from the core mold; and a hollow cylindrical guide positioned to at least cover the inner shape portion forming portion when the gas is injected by the injection device.

[0007] According to the manufacturing apparatus for hollow cylindrical molded products of this invention, when gas is injected by an injection device to remove the hollow cylindrical molded product from the core mold, the hollow cylindrical guide is positioned to at least cover the inner shape forming portion of the core mold. Therefore, even if the inner shape of the hollow cylindrical molded product expands (inflates) along the radial direction, it comes into contact with the hollow cylindrical guide, which prevents the inner shape of the hollow cylindrical molded product from expanding any further. In this way, it is possible to suppress the expansion (diameter expansion) of the inner shape of the hollow cylindrical molded product more than necessary, that is, to appropriately control the degree of expansion of the hollow cylindrical molded product, and to demold the hollow cylindrical molded product from the core mold more appropriately.

[0008] Furthermore, in the manufacturing apparatus for hollow cylindrical molded products according to the present invention, it is preferable that the inner shape portion of the hollow cylindrical molded product is formed in a bellows shape. This makes it possible to suppress the bellows shape portion of the hollow cylindrical molded product from expanding (increasing in diameter) more than necessary, that is, to appropriately control the degree of expansion of the bellows shape portion, and to demold the hollow cylindrical molded product from the core mold more appropriately.

[0009] Furthermore, in the manufacturing apparatus for hollow cylindrical molded products according to the present invention, it is preferable that the inner diameter of the guide is set to 200% or less of the outer diameter of the hollow cylindrical molded product. This makes it possible to more appropriately control the degree of radial expansion of the hollow cylindrical molded product.

[0010] Furthermore, in the manufacturing apparatus for hollow cylindrical molded products according to the present invention, it is preferable that the inner wall surface of the guide is flat. This makes it possible to smoothly guide the contact portion of the outer wall of the hollow cylindrical molded product along the inner wall surface of the guide even if the outer wall surface of the hollow cylindrical molded product comes into contact with the inner wall surface of the guide when the hollow cylindrical molded product expands along the axial direction, thereby suppressing damage to the outer wall surface of the hollow cylindrical molded product.

[0011] Furthermore, in the manufacturing apparatus for hollow cylindrical molded products according to the present invention, the elastic material is preferably a thermoplastic resin. This makes it possible to more appropriately demold hollow cylindrical molded products made of thermoplastic resin from the core mold.

[0012] Furthermore, the method for manufacturing a hollow cylindrical molded product according to the present invention is a method for manufacturing a hollow cylindrical molded product using a hollow cylindrical molded product manufacturing apparatus according to each of the above embodiments, and is characterized by comprising: a molding step of arranging the core mold having the inner shape forming portion in the cavity of a mold and injecting elastic material into the cavity to form the hollow cylindrical molded product; a first demolding step of opening the mold; an arrangement step of arranging the guide so as to at least cover the inner shape forming portion; a gas injection step of injecting the gas between the hollow cylindrical molded product and the core mold using the injection device; and a second demolding step of removing the hollow cylindrical molded product from the core mold.

[0013] According to the method for manufacturing a hollow cylindrical molded product of this invention, in the second demolding step of removing the hollow cylindrical molded product from the core mold, first, in the placement step, the guide is positioned so as to at least cover the inner shape forming portion, and then, in the gas injection step, the gas can be injected between the hollow cylindrical molded product and the core mold using an injection device. At this time, when the gas is injected by the injection device, the hollow cylindrical guide is positioned so as to at least cover the inner shape forming portion of the core mold, so even if the inner shape of the hollow cylindrical molded product expands (inflates) along the radial direction, it is possible to suppress further expansion of the inner shape of the hollow cylindrical molded product by contacting the hollow cylindrical guide. In this way, it is possible to suppress the expansion (diameter expansion) of the inner shape of the hollow cylindrical molded product more than necessary, that is, to appropriately control the degree of expansion of the hollow cylindrical molded product, and to demold the hollow cylindrical molded product from the core mold more appropriately. [Effects of the Invention]

[0014] This invention makes it possible to provide a manufacturing apparatus for hollow cylindrical molded products and a method for manufacturing hollow cylindrical molded products that can more appropriately demold hollow cylindrical molded products from a core mold. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing one embodiment of a hollow cylindrical molded product 10 manufactured by the manufacturing apparatus 20 (method for manufacturing a hollow cylindrical molded product) according to the present invention. [Figure 2A] This is a cross-sectional view showing a modified example of a hollow cylindrical molded product 10 manufactured by the manufacturing apparatus 20 (method for manufacturing a hollow cylindrical molded product) according to the present invention. [Figure 2B] This is a cross-sectional view showing a modified example of a hollow cylindrical molded product 10 manufactured by the manufacturing apparatus 20 (method for manufacturing a hollow cylindrical molded product) according to the present invention. [Figure 3A] This is a schematic diagram showing one embodiment of the manufacturing apparatus 20 for hollow cylindrical molded products according to the present invention. [Figure 3B]It is a front view showing the air outlet 53 and the chuck 54 shown in Fig. 3A. [Figure 4] It is a cross-sectional view showing the closed state (closing process) of the molding die 30 shown in Fig. 3A. [Figure 5] It is a cross-sectional view showing the injection process and the cooling and solidification process of the molding die 30 shown in Fig. 3A. [Figure 6] It is a cross-sectional view showing the first demolding process of the molding die 30 shown in Fig. 3A. [Figure 7] It is a cross-sectional view showing the second demolding process (placement process) of the molding die 30 shown in Fig. 3A. [Figure 8] It is a cross-sectional view showing the second demolding process (gas injection process) of the molding die 30 shown in Fig. 3A.

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment of an apparatus for manufacturing a hollow cylindrical molded product and a method for manufacturing a hollow cylindrical molded product according to the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment, and can be implemented in various modes with various modifications and improvements based on the knowledge of those skilled in the art.

[0017] (Hollow cylindrical molded product) As shown in Fig. 1, the hollow cylindrical molded product 10 is formed in a hollow cylindrical shape from an elastic material having elasticity. The hollow cylindrical molded product 10 has a main body 11 formed in a cylindrical shape, a first opening 12 provided at one end of the main body 11, and a second opening 13 provided at the other end of the main body 11. In this embodiment, the hollow cylindrical molded product 10 is formed in a cylindrical shape, but is not limited thereto, and may be formed in a cross-sectional polygonal shape such as an elliptical cross-sectional shape or a square cross-sectional shape. Further, the hollow cylindrical molded product 10 may be formed in a bottomed cylindrical shape. In this case, one of the both end openings 12, 13 of the main body 11 is closed. Furthermore, examples of the hollow cylindrical molded product include parts for automobiles and parts for home appliances.

[0018] The main body 11 has a bellows-shaped bellows part 14. A plurality of concave parts 14a1 formed by denting the outer wall 14a and convex parts 14a2 formed by protruding the outer wall 14a are provided on the outer wall 14a of the bellows part 14, and a plurality of concave parts 14b1 formed by denting the inner wall 14b and convex parts 14b2 formed by protruding the inner wall 14b are provided on the inner wall 14b of the bellows part 14. Thus, the hollow cylindrical molded product 10 has an outer shape part 16 which is the concave part 14a1 and ( / or) the convex part 14a2 on the outer wall 14a. Further, the hollow cylindrical molded product 10 has an inner shape part 15 which is the concave part 14b1 and ( / or) the convex part 14b2 on the inner wall 14b. In addition, in the present embodiment, both concave and convex parts (formed in a bellows shape) are formed as the inner shape part, but only concave parts may be formed, or only convex parts may be formed.

[0019] As shown in FIGS. 1 and 6, the inner diameter φ11a of the convex part 14b2 of the inner wall 14b is smaller than the inner diameter φ12 of the first opening 12, and the inner diameter φ11b of the concave part 14b1 of the inner wall 14b is larger than the inner diameter φ12 of the first opening 12. In addition, in the present embodiment, the inner diameter φ13 of the second opening 13 is set to be the same as the inner diameter φ12 of the first opening 12, but it may be set to a different value. On the other hand, since the inner diameter φ11b of the concave part 14b1 of the inner wall 14b is the same as the outer diameter of the convex part 34b2 of the core mold 32, the outer diameter of the convex part 34b2 of the core mold 32 is larger than the inner diameter φ11a of the convex part 14b2 of the inner wall 14b of the hollow cylindrical molded product 10 and the inner diameter φ12 (or the inner diameter φ13 of the second opening 13) of the first opening 12. Therefore, when the core mold 32 is normally pulled out, the convex part 34b2 of the core mold 32 may be caught by the convex part 14b2 of the inner wall 14b of the hollow cylindrical molded product 10, the first opening 12, or the second opening 13, and it may not be easily pulled out.

[0020] In this embodiment, the inner wall 14b is formed such that the inner diameter φ11a of the protrusion 14b2 of the inner wall 14b < the inner diameter φ12 of the first opening 12 < the inner diameter φ11b of the recess 14b1 of the inner wall 14b. However, as shown in Figure 2A, the inner wall 14b may be formed such that both the inner diameter φ11a of the protrusion 14b2 and the inner diameter φ11b of the recess 14b1 are larger than the inner diameter φ12 of the first opening 12. Alternatively, as shown in Figure 2B, the inner wall 14b may be formed such that both the inner diameter φ11a of the protrusion 14b2 and the inner diameter φ11b of the recess 14b1 are smaller than the inner diameter φ12 of the first opening 12.

[0021] Furthermore, in this embodiment, a thermoplastic resin is used as the elastic material. Examples of thermoplastic resins include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinyl acetate (PVAc), polyurethane (PUR), polytetrafluoroethylene (PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), ethylene vinyl alcohol resin (EVOH), polyamide (PA), polyacetal (POM), polycarbonate (PC), and modified polyphenylene ether (m-PPE, modified PPE, P). It is preferable to use materials such as PO, polyester (PEs), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), cyclic polyolefin (COP), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyetheretherketone (PEEK), thermoplastic polyimide (PI), and polyamideimide (PAI).

[0022] Furthermore, the elastic material is not limited to thermoplastic resins; rubber may also be used. Preferably, the rubber used is natural rubber (NR), epoxidized natural rubber (ENR), or synthetic rubber such as ethylene propylene diene rubber (EPDM), styrene butadiene rubber (SBR), nitrile rubber (NBR), butadiene rubber (BR), butyl rubber (isobutylene / isoprene rubber) (IIR), acrylic rubber (ACM), silicone rubber (SR), or fluororubber.

[0023] Furthermore, the elastic material is not limited to thermoplastic resins, but a dynamically crosslinked (vulcanized) thermoplastic elastomer (TPV) may also be used. A dynamically crosslinked thermoplastic elastomer is manufactured by melt-kneading a thermoplastic resin and rubber to crosslink the rubber within the matrix of the thermoplastic resin. As a dynamically crosslinked thermoplastic elastomer, combinations of the above-mentioned thermoplastic resin and rubber are possible, and it is preferable to use, for example, a combination of polypropylene (PP) and any one of ethylene propylene rubber (EPDM) and acrylic rubber (ACM); a combination of polyamide (PA) and any one of butyl rubber (IIR), acrylic rubber (ACM), nitrile rubber (NBR), epoxidized natural rubber (ENR), and silicone rubber (SR); a combination of polybutylene terephthalate (PBT) and any one of butyl rubber (IIR), acrylic rubber (ACM), and nitrile rubber (NBR); or a combination of polylactic acid (PLA) and natural rubber.

[0024] Furthermore, styrene-based thermoplastic elastomer (TPS) may be used as the elastic material. Preferably, the styrene-based thermoplastic elastomer (TPS) is of the type formed by sandwiching butadiene (B) between polystyrene (PS), or of the type formed by sandwiching isoprene (I) between polystyrene (PS).

[0025] (Manufacturing equipment for hollow cylindrical molded products) Furthermore, the manufacturing apparatus 20 for the hollow cylindrical molded product 10 described above will be explained with reference to the drawings. The manufacturing apparatus 20 is an apparatus for manufacturing the hollow cylindrical molded product 10 by injection molding, and as shown in Figure 3A, it comprises a molding die 30, a supply device 40, an injection device 50, and a guide 60. The injection device 50 and the guide 60 can be detachably attached (mounted) to the robot 70. The injection device 50 and the guide 60 may be attached to one robot 70 simultaneously, or they may be attached to two robots 70 separately. Alternatively, the injection device 50 and the guide 60 may be installed on the manufacturing line as separate devices rather than being attached to the robot 70.

[0026] The molding die 30 mainly comprises a cavity die (concave) 31 and a core die (convex) 32, as shown in Figure 4. The molding die 30 also includes a gate, ejector pins (neither of which are shown), and the like.

[0027] The cavity mold 31 has a pair of first cavity molds 31a and second cavity molds 31b. The first cavity mold 31a has a first recess 31c, and the second cavity mold 31b has a second recess 31d which can be positioned opposite the first recess 31c. The first recess 31c and the second recess 31d form an internal space 31e, and a core mold 32 can be positioned within this internal space 31e.

[0028] An outer wall forming portion 33 is formed on the inner wall surface of the first recess 31c of the first cavity mold 31a, which forms the outer wall of the hollow cylindrical molded product 10. The outer wall forming portion 33 has a first opening forming portion 33a that forms the outer wall surface of the first opening 12, an outer shape forming portion 33b that forms the outer shape portion 16, and a second opening forming portion 33c that forms the outer wall surface of the second opening 13. The outer shape forming portion 33b has a recess 33b1 for forming a protrusion 14a2 of the outer wall 14a and a protrusion 33b2 for forming a recess 14a1 of the outer wall 14a. In addition, an outer wall forming portion 33 is formed on the inner wall surface of the second recess 31d of the second cavity mold 31b, similar to the inner wall surface of the first recess 31c of the first cavity mold 31a, which forms the outer wall of the hollow cylindrical molded product 10.

[0029] The core mold 32 is a so-called core mold formed in a columnar (rod) shape. An inner wall forming portion 34 is formed on the outer wall surface of the core mold 32, which forms the inner wall of the hollow cylindrical molded product 10. The inner wall forming portion 34 has a first opening forming portion 34a that forms the inner wall surface of the first opening 12, an inner shape forming portion 34b that forms the inner shape portion 15, and a second opening forming portion 34c that forms the inner wall surface of the second opening 13. The inner shape forming portion 34b has a recess 34b1 for forming a protrusion 14b2 of the inner wall 14b and a protrusion 34b2 for forming the recess 14b1 of the inner wall 14b.

[0030] The core mold 32 has a core base portion 32a and a core tip portion 32b that is detachably attached to the core base portion 32a. The core tip portion 32b is fixed to the core base portion 32a by screws or the like during molding and is removed from the core base portion 32a during demolding. In this embodiment, an inner shape forming portion 34b and a second opening forming portion 34c are formed on the core base portion 32a, and a first opening forming portion 34a is formed on the core tip portion 32b.

[0031] A cavity 35 (sometimes referred to as a void) is formed in the molding die 30 when it is closed. When the first cavity mold 31a and the second cavity mold 31b are closed so as to sandwich the core mold 32, the two outer wall forming portions 33, 33 are positioned facing each other, and further, the core mold 32 is positioned within the internal space 31e formed by the two outer wall forming portions 33, 33 such that the inner wall forming portion 34 of the core mold 32 faces the two outer wall forming portions 33, 33. In this way, a cavity 35 for molding a hollow cylindrical molded product 10 is formed by the space formed by the outer wall forming portion 33 of the cavity mold 31 and the inner wall forming portion 34 of the core mold 32.

[0032] In this embodiment, the molding die 30 of the manufacturing apparatus 20 is a mold for injection molding, but it is not limited to this, and molds for extrusion molding, compression molding, or transfer molding may also be used.

[0033] The supply device 40 is a device that supplies and injects raw material (elastic material) for the molding of a hollow cylindrical molded product 10 into the cavity 35 formed when the molding die 30 is closed. As shown in Figure 3A, the supply device 40 has a supply unit 41 and an injection unit 42. The supply unit 41 supplies the raw material (for example, in pellet form) to the cylinder (not shown) of the injection unit 42. The injection unit 42 heats and melts the supplied raw material with a heater (not shown) provided in the cylinder, and injects the molten raw material into the cavity 35 at high speed and high pressure with a pressure feeding device (for example, a screw (not shown)).

[0034] The injection device 50 is a device that injects gas between the hollow cylindrical molded product 10 and the core mold 32 when removing the hollow cylindrical molded product 10 from the core mold 32. As shown in Figure 3A, the injection device 50 has a blower 51, a hose 52, an air outlet 53, and a chuck 54. The blower 51 sucks in gas, compresses it, and discharges it from an air outlet (not shown). The blower 51 can be a blower, an air compressor, etc. Air is used as the gas, but it is not limited to air, and other gases (nitrogen, oxygen, carbon dioxide, etc.) may also be used.

[0035] The hose 52 connects the blower 51 and the air outlet 53. One end of the hose 52 is connected to the air outlet of the blower 51, and the other end of the hose 52 is connected to the air outlet 53. The air outlet 53 is detachably connected to the first opening 12 of the hollow cylindrical molded product 10 to which it is installed, and sends air from the blower 51 into the hollow cylindrical molded product 10.

[0036] The air outlet 53 is configured to be inserted inside the opening of the hollow cylindrical molded product 10. Preferably, the air outlet 53 is connected to an opening that allows air to be supplied into the hollow cylindrical molded product 10, and is not limited to the first opening 12 of the hollow cylindrical molded product 10, but may also be connected to the second opening 13. Alternatively, the opening of the hollow cylindrical molded product 10 may be configured to be inserted inside the air outlet 53.

[0037] Specifically, the air outlet 53 is preferably formed in a cylindrical shape with a cross-sectional shape corresponding to the cross-sectional shape of the opening (first opening 12 in this embodiment) of the hollow cylindrical molded product 10 to which it is connected, and furthermore, a cross-sectional shape corresponding to the cross-sectional shape of the core mold used to form the opening. Furthermore, the air outlet 53 is preferably airtightly fitted to the first opening 12 of the hollow cylindrical molded product 10, and more preferably tightly fitted or snugly attached. That is, the outer diameter of the air outlet 53 is preferably set to the same diameter as the outer diameter of the first opening forming portion 34a of the core mold 32 (the inner diameter of the first opening 12 of the hollow cylindrical molded product 10), although it may be set to be slightly larger.

[0038] The chuck 54 is a device for gripping the opening of the hollow cylindrical molded product 10, which is attached to the air outlet 53, in cooperation with the air outlet 53. When air is blown between the hollow cylindrical molded product 10 and the core mold 32, the opening of the hollow cylindrical molded product 10 is gripped by the air outlet 53 and the chuck 54, thereby reliably preventing the hollow cylindrical molded product 10 from flying out of the core mold 32.

[0039] As shown in Figure 3A, the chuck 54 has a plurality of jaw portions 54a and a drive unit 54b that reciprocates each jaw portion 54a along the radial direction. The jaw portions 54a are formed in the shape of a plate with a circular arc cross-section, and for example, four are arranged at predetermined intervals (90 degrees). Three jaw portions 54a may be provided, in which case it is preferable to arrange them at 120-degree intervals. Five or more jaw portions 54a may also be provided. The drive unit 54b may drive the jaw portions 54a with air (positive or negative pressure), a motor, or hydraulics.

[0040] As shown in Figure 3B, each claw portion 54a is positioned facing the radially outer side of the air outlet 53. When each claw portion 54a is moved radially outward, it separates from the opening of the hollow cylindrical molded product 10 attached to the air outlet 53, and the chuck 54 is opened. On the other hand, when each claw portion 54a is moved radially inward, it contacts the opening of the hollow cylindrical molded product 10 attached to the air outlet 53, the chuck 54 is closed, and the chuck 54 cooperates with the air outlet 53 to grip the opening of the hollow cylindrical molded product 10.

[0041] The guide 60 is a hollow cylindrical guide positioned to at least cover the inner shaping portion 34b of the core mold 32 when gas is injected by the injection device 50 (see Figure 7). Preferably, the guide 60 extends by a predetermined amount in the direction in which the hollow cylindrical molded product 10 extends beyond the inner shaping portion 34b, including the inner shaping portion 34b. Since the first opening 12 of the hollow cylindrical molded product 10 is fixed to the air outlet 53 by the chuck 54, the direction in which the hollow cylindrical molded product 10 extends is towards the open end side of the hollow cylindrical molded product 10 (to the right in Figure 7). Preferably, the predetermined amount is set according to the amount of elastic deformation of the hollow cylindrical molded product 10 in the axial direction.

[0042] The inner diameter of the guide 60 is preferably set to 200% or less of the outer diameter φ21 of the hollow cylindrical molded product 10, and more preferably to 150% or less. Furthermore, the inner diameter φ31 of the guide 60 is preferably set to 110% or more of the outer diameter φ21 of the hollow cylindrical molded product 10. In other words, the inner diameter of the guide 60 is preferably in the range of 110% to 150% of the outer diameter φ21 of the hollow cylindrical molded product 10. In addition, the inner wall surface of the guide 60 is preferably flat. However, the inner wall surface of the guide 60 is not limited to being flat, and protrusions and recesses may be provided to suppress axial expansion of the hollow cylindrical molded product 10 or to obtain a desired shape.

[0043] As shown in Figure 3A, robot 70 is a so-called articulated robot, specifically a vertical articulated robot with six drive axes. Robot 70 is a so-called serial link type robot arm, with multiple drive axes (or arms) arranged in series. Robot 70 operates an end effector attached to its tip to a desired position and angle. In Figure 3A, an injection device 50 (particularly the air outlet 53 and chuck 54) and a guide 60 are attached as the end effector. Note that robot 70 is not limited to a vertical articulated robot; a horizontal articulated robot, a Cartesian robot, a parallel link robot (SCARA robot), etc., may also be used.

[0044] In addition, although the manufacturing apparatus 20 described above was configured with the injection device 50 and guide 60 mounted on a robot 70, it is not limited to this configuration, and the injection device 50 and guide 60 may be installed separately. Furthermore, in the above-described embodiment, the injection device 50 and guide 60 were mounted together on a single robot 70, but they may be mounted on separate robots 70.

[0045] The operation of the injection device 50 and guide 60 described above will now be explained. The robot 70 is driven, and the guide 60 attached to the tip is moved from its original position to a predetermined guide position (see Figure 7). At this time, the air outlet 53 of the injection device 50 attached to the tip is also moved to a position just before attachment. The air outlet 53 at the position just before attachment is moved along the axial direction by a drive unit (not shown) and moved toward the hollow cylindrical molded product 10, and the end of the air outlet 53 is attached to the first opening 12 of the hollow cylindrical molded product 10 (attachment position; position shown in Figure 7). At this time, the chuck 54 is also moved together with the air outlet 53. Subsequently, the drive unit 54b of the chuck 54 is driven, and the multiple claw portions 54a located in the open position (radially outward position) are moved radially inward, and the first opening 12 of the hollow cylindrical molded product 10 is gripped by the multiple claw portions 54a and the air outlet 53.

[0046] Subsequently, the blower 51 of the injection device 50 is driven, and air is sent out from the air outlet 53. The sent air is supplied into the hollow cylindrical molded product 10, whose first opening 12 is gripped by the chuck 54, and consequently between the hollow cylindrical molded product 10 and the core mold 32. The supplied air fills the hollow cylindrical molded product 10, expanding it sequentially from the first opening 12 side, and as a result, the hollow cylindrical molded product 10 is sequentially peeled away from the core mold 32. Finally, the hollow cylindrical molded product 10 is peeled away to the second opening 13, and the supplied air is sent out from the second opening 13 side of the hollow cylindrical molded product 10 (see Figure 8).

[0047] At this time, the guide 60 reliably suppresses further radial expansion of the hollow cylindrical molded product 10 as it is being sequentially peeled away. In particular, it is possible to suppress the radial expansion of the bellows section 14, which is prone to expansion. As a result, compared to the case where, if the guide 60 is not provided, the molded product (hollow cylindrical molded product 10) undergoes plastic deformation after yielding and the shape of the molded product does not return to its original shape beyond the amount of elastic deformation even if the load is removed (even if the supply of air is stopped), the guide 60 makes it possible to suppress further deformation of the molded product even if it deforms (suppress deformation that exceeds the yield point), that is, it is possible to suppress the deformation of the molded product to elastic deformation. Therefore, it is possible to return the shape of the molded product to its original shape when the load is removed.

[0048] Then, the robot 70 is driven, and the air outlet 53 of the injection device 50, which is located at the mounting position, is moved to its original position. At this time, the chuck 54 is also moved, and the hollow cylindrical molded product 10, whose first opening 12 is gripped by the chuck 54, is also moved, and the hollow cylindrical molded product 10 is pulled out of the core mold 32. At this time, it is preferable that air is continued to be blown into the hollow cylindrical molded product 10. After that, the drive unit 54b of the chuck 54 is driven, and the multiple claws 54a are moved radially outward, releasing the grip between the multiple claws 54a and the air outlet 53, and releasing the grip on the first opening 12 of the hollow cylindrical molded product 10.

[0049] (Method for manufacturing hollow cylindrical molded products) Furthermore, a method for manufacturing a hollow cylindrical molded product 10 using the manufacturing apparatus 20 described above will be explained. The method for manufacturing a hollow cylindrical molded product 10 includes a molding step, a first demolding step, and a second demolding step.

[0050] (molding process) The molding process includes a mold closing step of closing the molding die 30, an injection step of injecting molten raw material into the cavity 35, and a cooling and solidification step of cooling and solidifying the raw material inside the molding die 30. In the molding process, a core mold 32 having an inner shape forming section 34b is placed in the internal space 31e of the molding die 30, and elastic material is injected into the cavity 35 to form a hollow cylindrical molded product 10.

[0051] In the closing process, the first cavity mold 31a and the second cavity mold 31b are closed so as to sandwich the core mold 32 (see Figure 4). At this time, the two outer wall forming portions 33, 33 are positioned facing each other, and the core mold 32 is positioned within the internal space 31e formed by the two outer wall forming portions 33, 33 such that the inner wall forming portion 34 of the core mold 32 faces the two outer wall forming portions 33, 33. In this way, a cavity 35 for molding the hollow cylindrical molded product 10 is formed by the space formed by the outer wall forming portion 33 of the cavity mold 31 and the inner wall forming portion 34 of the core mold 32.

[0052] In the injection process, the supply device 40 melts the raw material (elastic material) for the molding of the hollow cylindrical molded product 10 into the cavity 35 formed when the molding die 30 is closed, and injects it. In the cooling and solidification process, the device waits until the molten material solidifies and the molded product (hollow cylindrical molded product 10) is formed (see Figure 5).

[0053] (Demolding process / 1st demolding process) The demolding process, which takes place after the molding process, includes a first demolding step (opening step) in which the molding die 30 is opened, and a second demolding step in which the hollow cylindrical molded product 10 is removed from the core mold 32. In the first demolding step, after the cooling and solidification step described above, that is, after the molten raw material has solidified and the hollow cylindrical molded product 10 has been formed, the molding die 30 is opened by moving the first cavity mold 31a and the second cavity mold 31b away from the core mold 32 (see Figure 6). At this time, the hollow cylindrical molded product 10, which is the molded product, is in close contact with the outer wall surface of the core mold 32.

[0054] Furthermore, during the demolding process, the temperature of the hollow cylindrical molded product 10 when it is removed from the core mold 32 is preferably 40°C to 60°C.

[0055] (Second demolding process) The second demolding step includes, after the first demolding step, a positioning step of positioning the guide 60 so as to cover at least the inner shape forming portion 34b, and a gas injection step of injecting air (gas) between the hollow cylindrical molded product 10 and the core mold 32 using an injection device 50.

[0056] (Placement process) First, the core tip 32b of the core mold 32 is removed from the core base 32a. The removal of the core tip 32b may be performed manually by an operator or automatically by the robot 70. Next, the robot 70 is driven to move the guide 60 attached to the tip from its original position to a predetermined guide position (see Figure 7). At this time, the air outlet 53 of the injection device 50 attached to the tip is also moved to a position just before attachment. The tip end of the guide 60 (left end in Figure 7) is located on the tip side of the left end (one end) of the bellows section 14 and thus the inner shape forming section 34b, and the base end of the guide 60 (right end in Figure 7) is located on the base side of the right end (other end) of the bellows section 14 and thus the inner shape forming section 34b.

[0057] In this embodiment, the core tip portion 32b was removed first, and then the guide 60 was moved to the guide position. However, the guide 60 may be moved to the guide position first, and then the core tip portion 32b may be removed.

[0058] (Gas injection process) First, the air outlet 53, located just before mounting, is moved axially by a drive unit (not shown) towards the hollow cylindrical molded product 10, and the end of the air outlet 53 is mounted on the first opening 12 of the hollow cylindrical molded product 10 (mounting position; position shown in Figure 7). At this time, the chuck 54 is also moved together with the air outlet 53. Subsequently, the drive unit 54b of the chuck 54 is driven, and the multiple jaw portions 54a are moved radially inward, and the first opening 12 of the hollow cylindrical molded product 10 is gripped by the multiple jaw portions 54a and the air outlet 53. After that, the blower 51 of the injection device 50 is driven, and air is discharged from the air outlet 53.

[0059] The air that is sent out is supplied into the hollow cylindrical molded product 10, which is gripped at the first opening 12 by the chuck 54, and consequently into the space between the hollow cylindrical molded product 10 and the core mold 32. The supplied air fills the hollow cylindrical molded product 10, expanding it sequentially from the first opening 12 side, and as a result, the hollow cylindrical molded product 10 is sequentially peeled away from the core mold 32. Finally, the hollow cylindrical molded product 10 is peeled away to the second opening 13, and the supplied air is sent out from the second opening 13 side of the hollow cylindrical molded product 10 (see Figure 8).

[0060] In this case, the guide 60 reliably prevents the expanding hollow cylindrical molded product 10 from expanding further in the radial direction. In particular, it is possible to suppress the radial expansion of the bellows section 14, which is prone to expansion. As a result, compared to the case where, if the guide 60 is not provided, the molded product (hollow cylindrical molded product 10) undergoes plastic deformation after yielding and does not return to its original shape beyond the amount of elastic deformation even when the load is removed (even when the air supply is stopped), the guide 60 makes it possible to suppress further deformation of the molded product even if it deforms (suppress deformation that exceeds the yield point), that is, it is possible to suppress the deformation of the molded product to elastic deformation. Therefore, when the load is removed, it is possible to return the shape of the molded product to its original shape.

[0061] Then, the robot 70 is driven, and the air outlet 53 of the injection device 50, which is located at the mounting position, is moved to its original position. At this time, the hollow cylindrical molded product 10, whose first opening 12 is gripped by the chuck 54, is also moved, and the hollow cylindrical molded product 10 is pulled out from the core mold 32. After that, the drive unit 54b of the chuck 54 is driven, and the multiple claws 54a are moved radially outward, releasing the grip between the multiple claws 54a and the air outlet 53, and releasing the grip on the first opening 12 of the hollow cylindrical molded product 10.

[0062] (Effects and mechanisms of the embodiment) The manufacturing apparatus 20 for a hollow cylindrical molded product 10 according to the above-described embodiment is a manufacturing apparatus 20 for a hollow cylindrical molded product 10 which is formed in a hollow cylindrical shape and has an inner shaped portion 15 which is a recess 14b1 and / or a convex portion 14b2 on the inner wall 14b and is made of an elastic material, comprising: a core mold (core mold) 32 having an inner shaped portion forming portion 34b which forms the inner shaped portion 15 of the hollow cylindrical molded product 10; an injection device 50 which injects gas between the hollow cylindrical molded product 10 and the core mold 32 when removing the hollow cylindrical molded product 10 from the core mold 32; and a hollow cylindrical guide 60 which is positioned to at least cover the inner shaped portion forming portion 34b when the gas is injected by the injection device 50.

[0063] According to the manufacturing apparatus 20 for the hollow cylindrical molded product 10 of this embodiment, when gas is injected by the injection device 50 when removing the hollow cylindrical molded product 10 from the core mold 32, the hollow cylindrical guide 60 is positioned to at least cover the inner shaped portion forming portion 34b of the core mold 32. Therefore, even if the inner shaped portion 15 of the hollow cylindrical molded product 10 expands (inflates) along the radial direction, it comes into contact with the hollow cylindrical guide 60, which suppresses further expansion of the inner shaped portion 15 (bellows portion 14) of the hollow cylindrical molded product 10. In this way, it is possible to suppress the inner shaped portion 15 of the hollow cylindrical molded product 10 from expanding (increasing in diameter) more than necessary, that is, to appropriately control the degree of expansion of the hollow cylindrical molded product 10, and to demold the hollow cylindrical molded product 10 more appropriately.

[0064] Furthermore, in the manufacturing apparatus 20 for the hollow cylindrical molded product 10 according to this embodiment, it is preferable that the inner diameter of the guide 60 be set to 200% or less of the outer diameter of the hollow cylindrical molded product 10. This makes it possible to more appropriately control the degree of radial expansion of the hollow cylindrical molded product 10.

[0065] Furthermore, in the manufacturing apparatus 20 for the hollow cylindrical molded product 10 according to this embodiment, it is preferable that the inner wall surface of the guide 60 is flat. This makes it possible to smoothly guide the contact portion of the outer wall of the hollow cylindrical molded product 10 along the inner wall surface of the guide 60 even if the outer wall surface of the hollow cylindrical molded product 10 comes into contact with the inner wall surface of the guide 60 when the hollow cylindrical molded product 10 expands along the axial direction, thereby preventing damage to the outer wall surface of the hollow cylindrical molded product 10.

[0066] Furthermore, in the manufacturing apparatus 20 for the hollow cylindrical molded product 10 according to this embodiment, it is preferable that the inner shape portion 15 of the hollow cylindrical molded product 10 is formed in a bellows shape. According to this, even if the hollow cylindrical molded product 10 has a bellows-shaped inner shape portion 15 having a plurality of recesses 14b1 and / or protrusions 14b2, it is possible to suppress the bellows-shaped inner shape portion 15 of the hollow cylindrical molded product 10 from expanding (increasing in diameter) more than necessary, that is, to appropriately control the degree of expansion of the bellows-shaped inner shape portion 15, and to demold the hollow cylindrical molded product 10 more appropriately.

[0067] Furthermore, in the manufacturing apparatus 20 for the hollow cylindrical molded product 10 according to this embodiment, the elastic material is preferably a thermoplastic resin. This makes it possible to more appropriately demold the hollow cylindrical molded product 10 made of thermoplastic resin from the core mold. In addition, by using resin for the hollow cylindrical molded product 10, it is possible to reduce the weight and cost of the part compared to when it is made of rubber. It is also possible to reduce CO2 emissions at the manufacturing stage. Furthermore, it becomes possible to recycle the material with low energy consumption.

[0068] Furthermore, the method for manufacturing the hollow cylindrical molded product 10 according to this embodiment is a method for manufacturing the hollow cylindrical molded product 10 using a manufacturing apparatus 20 for the hollow cylindrical molded product 10, and is characterized by comprising: a molding step of arranging a core mold 32 having an inner shape forming portion 34b in the cavity 35 of a mold (molding mold 30), and injecting elastic material into the cavity 35 to mold the hollow cylindrical molded product 10; a first demolding step of opening the mold 30; an arrangement step of arranging a guide 60 so as to cover at least the inner shape forming portion 34b; a gas injection step of injecting gas between the hollow cylindrical molded product 10 and the core mold 32 using an injection device 50; and a second demolding step of removing the hollow cylindrical molded product 10 from the core mold 32.

[0069] According to the manufacturing method for the hollow cylindrical molded product 10 of this embodiment, in the second demolding step of removing the hollow cylindrical molded product 10 from the core mold 32, first, in the placement step, the guide 60 is positioned so as to at least cover the inner shape forming portion 34b, and then, in the gas injection step, gas can be injected between the hollow cylindrical molded product 10 and the core mold 32 by the injection device 50. At this time, when gas is injected by the injection device 50, the hollow cylindrical guide 60 is positioned so as to at least cover the inner shape forming portion 34b of the core mold 32, so even if the inner shape portion 15 of the hollow cylindrical molded product 10 expands (inflates) along the radial direction, it can be prevented from expanding further by contacting the hollow cylindrical guide 60. In this way, it is possible to suppress the internal shape portion 15 of the hollow cylindrical molded product 10 from expanding (increasing in diameter) more than necessary, that is, to appropriately control the degree of expansion of the hollow cylindrical molded product 10, and to demold the hollow cylindrical molded product 10 more appropriately.

[0070] In the embodiment described above, the core mold 32 is formed from two parts: the core base end 32a and the core tip end 32b, which is removed when attaching the air outlet 53 to the hollow cylindrical molded product 10. However, the core mold 32 may be formed from a single part. This would simplify the structure of the manufacturing apparatus 20 and simplify the manufacturing process. In this case, the inner diameter of the air outlet 53 is preferably set to be larger than the outer diameter of the first opening forming portion 34a and smaller than the outer diameter of the first opening 12 of the hollow cylindrical molded product 10, in order to easily insert the air outlet 53 between the hollow cylindrical molded product 10 and the core mold 32. Furthermore, the thickness of the air outlet 53 is preferably set to be as thin as possible from the viewpoint of ease of insertion between the hollow cylindrical molded product 10 and the core mold 32, and is preferably set to be at least thinner than the thickness of the opening of the hollow cylindrical molded product 10. The air outlet 53 is preferably formed in a cylindrical shape that corresponds to the cross-sectional shape of the opening (first opening 12 in this embodiment) of the hollow cylindrical molded product 10 to which it is connected, and furthermore, to the cross-sectional shape of the core mold used to form the opening. [Explanation of symbols]

[0071] 10...Hollow cylindrical molded product, 14b...Inner wall, 14b1...Recess, 14b2...Convex part, 15...Inner shape part, 20...Manufacturing equipment, 30...Mold (molding mold), 32...Core mold (core mold), 34b...Inner shape part forming part, 35...Cavity, 50...Injection device, 60...Guide.

Claims

1. A manufacturing apparatus for hollow cylindrical molded products, which is formed in a hollow cylindrical shape and has an inner shape portion having a recess and / or a convex portion on its inner wall, and is made of an elastic material, A core mold having an inner shape forming portion that forms the inner shape portion of the hollow cylindrical molded product, When removing the hollow cylindrical molded product from the core mold, an injection device is used to inject gas between the hollow cylindrical molded product and the core mold. When injecting the gas using the injection device, a hollow cylindrical guide with open ends is provided, which is positioned to at least cover the inner shaped portion forming portion. Equipped with, The aforementioned core type is, It has a core base end and a core tip that is detachably attached to the core base end, The aforementioned core tip is removed from the core base when the hollow cylindrical molded product is removed from the core mold. The tip of the core is provided with a first opening forming portion that forms the first opening of the hollow cylindrical molded product. The base end of the core is provided with a second opening forming portion that forms a second opening in the hollow cylindrical molded product, The injection device has a cylindrical air outlet that is airtightly fitted inside the first opening of the hollow cylindrical molded product, The air outlet is installed inside the first opening after the tip of the core is removed from the base of the core. A manufacturing apparatus for a hollow cylindrical molded product, characterized in that the gas injected by the injection device is discharged from the air outlet, the discharged gas is supplied between the hollow cylindrical molded product and the core base end, and discharged from the second opening of the hollow cylindrical molded product.

2. The apparatus for manufacturing a hollow cylindrical molded product according to Claim 1, characterized in that the guide is a hollow cylindrical shape with both ends open and having a continuous shape without breaks in the circumferential direction.

3. The apparatus for manufacturing a hollow cylindrical molded product according to claim 1 or 2, wherein the core base end further comprises the inner shape forming portion.

4. The manufacturing apparatus for a hollow cylindrical molded product according to claim 1 or 2, wherein the injection device further comprises a chuck which is a device for gripping the first opening of the hollow cylindrical molded product attached to the air outlet in cooperation with the air outlet.

5. A method for manufacturing a hollow cylindrical molded article using the manufacturing apparatus for hollow cylindrical molded articles described in claim 1 or claim 2, A molding process in which the core mold having the inner shape forming portion is placed inside the cavity of the mold, and elastic material is injected into the cavity to form the hollow cylindrical molded product, After the molding process, a first demolding step is performed in which the mold is opened. The process includes a second demolding step, after the first demolding step, in which the hollow cylindrical molded product is removed from the core mold. The second demolding step is, After the first demolding step, the arrangement step involves positioning the guide so as to at least cover the inner shape forming portion, The system includes a gas injection step in which the gas is injected between the hollow cylindrical molded product and the core mold using the injection device, The aforementioned arrangement step is, Remove the tip portion of the core from the base portion of the core, Move the guide to a guide position that at least covers the inner shaped portion forming portion. The aforementioned gas injection step is, Move the air outlet to a mounting position where it is attached to the first opening of the hollow cylindrical molded product. A method for manufacturing a hollow cylindrical molded product, characterized by supplying the gas discharged from the air outlet between the hollow cylindrical molded product and the core base end.

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