JP5195307B2 - Injection molding apparatus and injection molding method - Google Patents

Description

  The present invention relates to an injection molding apparatus, and more particularly to an injection molding apparatus capable of producing a hollow molded body.

  A technique for producing a hollow molded body by injection molding of resin is known (for example, Patent Document 1).

JP 2007-326325 A

  However, in the prior art, since the resin hollow molded body contracts during production, the hollow molded body sticks to the male mold and is difficult to come off from the male mold.

  An object of the present invention is to solve at least one of the above-described problems and to provide a technique capable of easily removing a resin hollow molded body from a male mold.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
An injection molding apparatus comprising a female mold and a male mold, wherein the male mold is disposed on a male mold body and the top of the male mold, and the female mold and the male mold A push-up core for pushing up a hollow molded body formed in a cavity between the hollow molded body and the male mold when the push-up core pushes up the hollow molded body. An injection port for blowing air into a gap generated between the injection molding device and the injection molding device further comprising a push-up device for pushing up the push-up core toward the top of the male mold.
According to this application example, the hollow molded body is pushed up by the push-up core, and a gap is generated between the hollow molded body and the male mold, so that the hollow molded body can be easily detached from the male mold. Further, since air can be blown into the gap between the hollow molded body and the male mold, it is possible to improve the releasability between the hollow molded body and the male mold.

[Application Example 2]
The injection molding apparatus according to Application Example 1, further comprising a rotating device that rotates the push-up core.
According to this application example, since the push-up core is rotated, it is possible to easily peel off the adhesion between the hollow molded body and the male mold.

[Application Example 3]
In the injection molding apparatus according to Application Example 1 or Application Example 2, the mold release apparatus is further disposed near the base of the convex shape of the male mold and releases the end of the hollow molded body from the male mold. An injection molding apparatus comprising:
According to this application example, the releasability at the end of the hollow molded body can be improved.

[Application Example 4]
In the injection molding apparatus according to Application Example 3, the end of the hollow molded body that is disposed in the vicinity of the mold release device of the male mold and is released by the mold release apparatus, and the male mold An injection molding apparatus comprising a second air outlet for blowing air therebetween.
According to this application example, the releasability at the end of the hollow molded body can be further improved.

[Application Example 5]
The injection molding apparatus according to any one of Application Examples 1 to 4, wherein the air is cooled air.

[Application Example 6]
In the injection molding apparatus according to any one of Application Examples 1 to 5, the cavity includes a first cavity portion having a hollow cylindrical shape and a second cavity portion having a ring shape along a conical surface. A second cavity portion that has one end connected to the first cavity portion and is inclined so that a normal line in the ring shape intersects outside the hollow molded body; A third cavity portion having a ring shape with one end connected to the end and a convex curved surface on the outside, and connected to the other end of the third cavity portion to form the outermost peripheral side wall of the hollow molded body An injection molding apparatus comprising: a fourth cavity portion having a hollow cylindrical shape.
According to this application example, it is possible to improve the bonding adhesiveness with other components when using the hollow molded body.

  The present invention can be realized in various forms. For example, in addition to an injection molding apparatus and an injection forming method, the present invention can be realized in various forms such as a method for manufacturing a resin liner.

  FIG. 1 is an explanatory diagram showing the appearance of a tank created in one embodiment of the present invention. FIG. 2 is an explanatory view showing a cross section of the tank. The tank 10 includes a base 100, an outer cylinder 200, and a liner 300. The base 100 is used for filling the tank 10 with gas or discharging the gas from the tank 10. A flange 110 (flange) is formed on the outer periphery of the base 100 near the center in the direction of the central axis 101 of the base 100. The collar 110 is formed to protrude to the outer periphery along a plane perpendicular to the central axis 101. Further, the flange 110 has a tapered shape or a substantially trapezoidal shape such that the tip end side of the flange is thin.

  The liner 300 is an inner shell for sealing the inside of the tank. The liner 300 has a substantially cylindrical shape. Here, the liner 300 is formed by joining two liners 300a and 300b. A base 100 is attached to the upper and lower portions of the liner 300. The liner 300 may have the base 100 only in one liner 300a and may not have the base 100 in the other liner 300b. The liner 300 is made of a heat-shrinkable material such as nylon, ethylene vinyl alcohol copolymer (EVOH), or polyethylene. The configuration of the liner 300 may include a plurality of layers including an outer layer made of a heat-shrinkable material and an inner layer made of a non-heat-shrinkable material such as epoxy, glass, or metal. .

  The outer cylinder 200 is formed outside the liner 300 and functions as a pressure-resistant shell of the tank 10. As a material of the outer cylinder 200, fiber reinforced plastic (FRP) can be used. The end portion of the liner 300 and the end portion of the outer cylinder 200 are in close contact with each other so as to sandwich the flange 110 of the base 100, and gas leakage from the joint portion between the base 100 and the liner 300 is suppressed. In FIG. 1, the liner 300 is covered by the outer cylinder 200.

  FIG. 3 is an explanatory diagram for explaining a manufacturing process of the tank. First, as shown in FIG. 3A, a base 100 and a liner 300 are prepared. For example, the liner 300 is manufactured using, for example, an injection molding apparatus. The liner 300 has a cylindrical shape, and one opening 305 of the liner 300 is narrowed. The base 100 is joined to the narrowed opening 305.

  Next, as shown in FIG. 3B, the base 100 is press-fitted into the opening 305 of the liner 300. Next, as shown in FIG. 3C, the liner 300 is heat-treated. As a result, the liner 300 is thermally contracted, and the end portion of the liner 300 and the flange 110 of the base 100 are joined. When the liner 300 includes a plurality of layers, the liner 300 is preferably formed so that the end of the outer layer of the liner 300 is positioned above the flange 110. Thus, when the liner 300 is thermally contracted, the outer layer of the liner 300 is applied to the upper side of the flange 110. As a result, since the brim 110 is sandwiched between the inner layer and the outer layer, the joint between the brim 110 and the liner 300 is strengthened.

  Next, as shown in FIG. 3D, the liner 300 to which the base 100 is attached is joined. The opposite sides of the liner 300 to which the base 100 is attached are aligned. Next, for example, a laser torch is used to irradiate the joint between the two liners 300 with laser. As a result, the resin at the joint between the two liners 300 is heated to weld the two liners 300. In this case, it is preferable that one liner 300a is formed of a laser-absorbing resin and the other liner 300b is formed of a laser-transmitting resin. Thereby, welding of liner 300a and liner 300b becomes easy. Further, in this case, it is preferable that the resin materials of the liner 300a and the liner 300b are the same, and a pigment is added to the resin material of one of the liners 300a so as to have laser absorption. This is because there is no difference in strength between the liner 300a and the liner 300b if the materials of the liner 300a and the liner 300b are the same. As the pigment, for example, carbon black or ferrous oxide (FeO) can be used.

  Next, as shown in FIG. 3E, the reinforcing fiber impregnated with the resin is wound around the liner 300. As fibers for reinforcing the resin, glass fibers, carbon fibers, and aramid fibers (for example, polyparaphenylene terephthalamide fibers (Kevlar fiber, Kevlar is a registered trademark)) can be used. In addition, as a resin reinforced with fibers, an epoxy resin, an epoxy acrylate resin, or a polyester resin can be used. In addition, it is possible to adjust mechanical properties, such as tensile strength of the outer cylinder 200, with the pattern of the reinforcing fiber winding. Next, as shown in FIG. 3F, the reinforcing fibers wound around the liner 300 are heat-cured. Thereby, the reinforced fiber impregnated with the resin becomes FRP and forms the outer cylinder 200. In the present embodiment, the step of winding the reinforcing fiber impregnated with resin around the liner 300 and then heat-curing it to obtain the outer cylinder 200 is called a filament winding step.

  FIG. 4 is an explanatory view showing an injection apparatus for manufacturing the liner 300. The injection molding apparatus 20 includes a female mold 400 and a male mold 500. FIG. 4A is a side cross-sectional view schematically showing a female mold, and FIG. 4B is a side cross-sectional view schematically showing a male mold. FIG. 4C is a plan view of the male mold as seen from above.

  The female mold 400 has a concave shape, and is used as a fixed mold when the liner 300 is manufactured. The female mold 400 includes a resin injection path 405 and a resin injection device 410. The resin injection device 410 is used to inject resin into a cavity (described later) generated between the female mold 400 and the male mold 500 via the resin injection path 405.

  The male mold 500 has a convex cylindrical shape, and is used as a moving mold when the liner 300 is manufactured. The male mold 500 includes a male mold body 501, a push-up core 510, and a slide core 540. The push-up core 510 is arranged on the convex top of the male mold 500. A rotating device 520 is connected to the push-up core 510 via a shaft 515. A screw mechanism 525 is provided at the lower part of the shaft 515 and the lower part of the male mold. When the rotating device 520 rotates the shaft 515, the push-up core 510 is moved in the vertical direction in FIG. 4B along the shaft 515 by the screw mechanism 525. Note that the push-up core 510 may be moved by a press mechanism without using the screw mechanism 525. The push-up core 510 has an air passage 530 inside. The air passage 530 is connected to a gap 535 between the male mold body 501 and the push-up core 510. Here, the gap 535 is formed at the interface between the male mold body 501 and the push-up core 510. Here, the gap 535 is set to a size that allows air to pass but does not allow resin to enter. The upper end of the gap 535 is an air outlet 537. The air passage 530 passes through the shaft 515 and is connected to the air supply pipe 600. As a result, air is blown out from the air outlet 537 through the gap 535 from the air passage 530.

  The slide core 540 is provided on the outer periphery of the base of the column of the male mold 500. Note that the slide core 540 is provided not only on the entire outer periphery of the base of the cylinder but only on a part thereof. In the present embodiment, as shown in FIG. 4C, the slide cores 540 are arranged on the right and left portions of the cylinder at intervals of 180 degrees. Note that the slide core 540 can be arranged in various ways, such as the two-way arrangement at intervals of 180 degrees of this embodiment, the three-way arrangement at intervals of 120 degrees, and the four-direction arrangement at intervals of 90 degrees. The slide core 540 includes a claw 545 and air passages 550 and 555. The slide core 540 is movable in the radial direction of the cylinder. The claw 545 moves along with the slide core 540. At that time, the tab 545 hooks the lower end portion of the liner 300. As a result, the slide core 540 opens a gap between the male mold body 501 and the liner 300. The air passage 550 is provided inside the slide core 540 and is connected to the air supply pipe 600. The air passage 555 connects the air outlet 557 provided at the base of the claw 545 and the air passage 550. Note that the air passage 555 and the air outlet 557 are set to a size that allows air to pass but does not allow resin to enter.

  FIG. 5 is an explanatory view showing a state in which the male mold is housed in the female mold. A cavity 310 for filling resin is formed between the female mold 400 and the male mold 500. The cavity 310 includes four cavity portions 311 to 314. The first cavity portion 311 is on the center side and has a hollow cylindrical shape. One end of the second cavity portion 312 is connected to the end of the first cavity portion 311. The second cavity portion 312 has a ring shape along the conical surface. The ring shape of the second cavity portion 312 is inclined so that the normal line 312 a in the ring shape intersects outside the cavity 310. The inclination preferably coincides with the inclination of the taper shape or the substantially trapezoidal shape of the flange 110 of the base 100. This makes it possible to strengthen the bonding between the liner 300 formed in the cavity 310 and the flange 110. One end of the third cavity portion 313 is connected to the other end of the second cavity portion 312. The third cavity portion 313 has a ring shape formed with a convex curved surface on the outside. The fourth cavity portion 314 is connected to the other end of the third cavity portion 313. The fourth cavity portion 314 is on the outermost periphery of the cavity 310 and has a hollow cylindrical shape. A resin injection path 405 is connected to a connection position between the second cavity portion 312 and the third cavity portion 313. From here, resin is injected into the cavity 310.

  FIG. 6 is an explanatory view showing a state in which resin is injected and injected into the cavity. A liner 300 is formed in the cavity 310. After the resin is cooled in the mold, the female mold 400 and the male mold 500 are opened.

  FIG. 7 is an explanatory view showing a state in which the female mold and the male mold are opened. In FIG. 7, the female mold 400 is not shown. In general, injection-molded resin shrinks when the temperature decreases. When the resin shrinks, the resin and the female mold are unlikely to adhere to the female mold 400 because the resin shrinks in the direction of releasing the resin. On the other hand, when the resin contracts, the resin and the male mold 500 are easily bonded to the male mold 500 because the resin contracts in the direction in which the resin is in close contact with the male mold 500.

  FIG. 8 is an explanatory diagram illustrating a process of removing the liner from the male mold. FIG. 9 is an explanatory diagram showing an enlarged boundary portion (X portion in FIG. 8) between the push-up core and the liner. First, the push-up core 510 is moved upward in the drawing. In this embodiment, the rotating device 520 rotates the shaft 515. By the screw mechanism 525, the push-up core 510 moves upward in the drawing while rotating, and pushes up the liner 300. By pushing up the push-up core 510 while rotating it, it becomes possible to remove the sticking between the liner 300 and the push-up core 510 or the male mold body 501. In order to alleviate the stress concentration when the liner 300 is pushed up, the contact area between the pushed-up core 510 and the liner 300 should be large to some extent. When the push-up core 510 is pushed up, a separation space 700 is generated between the liner 300 and the male mold body 501 as shown in FIG. Since the separation space is in a decompressed state as long as it is not connected to the outside air, air may be supplied to the separation space 700 via the air passages 530 and 535. In this way, the releasability between the liner 300 and the male mold body 501 can be improved. At this time, cooling air may be used as the air. When cooling air is used, the male mold 500 and the liner 300 can be cooled.

  FIG. 10 is an explanatory view showing, in an enlarged manner, the vicinity of the tab 545 of the slide core 540 (Y portion in FIG. 8). FIG. 11 is an explanatory view of FIG. 10 viewed from above. As the push-up core 510 moves, the liner 300 moves upward. This creates a space 705 between the slide core 540 and the liner 300. Further, the slide core 540 moves leftward. At this time, the tab 545 is caught by the lower part of the liner 300, and the liner 300 is pulled leftward. As a result, a separation space 710 is generated between the liner 300 and the male mold body 501. Note that the amount of movement of the slide core 540 may be just the amount of movement that produces the separation space 710. This is because the adhesion between the liner 300 and the male mold body 501 may be removed. At this time, air may be supplied to the separation space 710 via the air passages 550 and 555. The air may be cooling air.

  FIG. 12 is an explanatory diagram showing a state in which the liner has been removed. The manufactured liner 300 is used in the tank manufacturing process described with reference to FIG.

  As described above, according to this embodiment, the liner 300 is pushed up while the push-up core 510 is rotated, so that the liner can be easily detached from the male mold 500. Further, since the push-up core 510 is pushed up rather than the push-out pin, the stress concentration at the push-up portion can be relaxed. Thereby, damage of liner 300 can be controlled. In addition, since air is supplied to the separation space 700 generated by pushing up the push-up core 510, the releasability between the liner 300 and the male mold body 501 can be improved. Further, according to the present embodiment, the liner 300 can be easily detached from the male mold main body 501, so that the manufacturing cycle of the liner 300 can be shortened. Thereby, the manufacturability of the liner 300 can be improved.

  Further, according to the present embodiment, a gap is created between the liner 300 and the male mold body 501 using the slide core 540. This makes it possible to remove the close contact with the male mold body 501 on the side surface of the liner 300. Further, since air is supplied to the separation space 710 generated by the movement of the slide core 540, the releasability between the liner 300 and the male mold body 501 can be improved.

  In this embodiment, the push-up core 510 is pushed upward while rotating, but the push-up core 510 may be pushed up without rotating. If the push-up core 510 is pushed up in the top direction, the peeling space 700 can be generated without rotating. When the push-up core 510 is rotated, the liner 300 and the male mold 500 can be easily separated from each other as compared with the case where the push-up core 510 is not rotated. In this embodiment, when the shaft 515 is rotated, the push-up core 510 is pushed up in the top direction by the screw mechanism 525. However, the rotation device and the push-up device may be separate devices.

  In this embodiment, the slide core 540 has the air outlet 557. However, the slide core 557 may have a configuration without the air outlet 557. When the push-up core 510 moves in the top direction, a space 705 is generated between the liner 300 and the slide core 540. Since the space 705 is in contact with the outside air, air can be supplied from the space 705 to the separation space 710 through the side of the claw 545 even if the air outlet 557 is not provided. In this embodiment, since the air blowing port 557 is provided, it is possible to supply high-purity air or cooled air to the separation space 710.

  In this embodiment, the female mold is a fixed mold and the male mold is a moving mold, but the female mold may be a moving mold and the male mold may be a fixed mold.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

It is explanatory drawing which shows the external appearance of the tank produced in one Example of this invention. It is explanatory drawing which shows the cross section of a tank. It is explanatory drawing explaining the manufacturing process of a tank. 5 is an explanatory view showing a mold for manufacturing the liner 300. FIG. It is explanatory drawing which shows the state which accommodated the male metal mold | die in the female metal mold | die. It is explanatory drawing which shows the state by which resin was inject | poured and injected into the cavity. It is explanatory drawing which shows the state which opened the female metal mold | die and the male metal mold | die. It is explanatory drawing explaining the process of removing a liner from a male metal mold | die. It is explanatory drawing which expands and shows the boundary part (X part of FIG. 8) of a pushing-up core and a liner. It is explanatory drawing which expands and shows the nail | claw 545 vicinity (Y part of FIG. 8) of the slide core 540. FIG. It is explanatory drawing which looked at FIG. 10 from upper direction. It is explanatory drawing which shows the state which the liner removed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Tank 20 ... Injection molding apparatus 100 ... Base 101 ... Center axis 110 ... Collar 200 ... Outer cylinder 300 ... Liner 300a ... Liner 300b ... Liner 305 ... Opening part 310 ... Cavity 311 ... 1st cavity part 312 ... 2nd Cavity part 312a ... Normal line 313 ... Third cavity part 314 ... Fourth cavity part 400 ... Female mold 405 ... Resin injection path 410 ... Resin injection device 500 ... Male mold 501 ... Male mold body 510 ... Push-up core 515: shaft 520 ... rotating device 525 ... screw mechanism 530 ... air passage 535 ... gap 537 ... air outlet 540 ... slide core 545 ... claw 550 ... air passage 555 ... air passage 557 ... air outlet 600 ... air supply pipe 700 ... Peeling space 705 ... Space 710 ... Peeling space

Claims (6)

An injection molding device,
A female mold and a male mold,
The male mold is
A male mold body,
A push-up core disposed at the top of the male mold and for pushing up a hollow molded body formed in a cavity between the female mold and the male mold;
An air outlet provided in the push-up core, for blowing air into a gap formed between the hollow mold and the male mold when the push-up core pushes up the hollow mold;
Have
The injection molding apparatus further includes:
A push-up device for pushing up the push-up core toward the top of the male mold ;
An injection molding apparatus comprising: a rotation device that rotates the push-up core . The injection molding apparatus according to claim 1 , further comprising:
An injection molding apparatus provided with a mold release device that is arranged near the convex base of the male mold and releases the end of the hollow molded body from the male mold. The injection molding apparatus according to claim 2 , further comprising:
A second air outlet for blowing air between the end of the hollow molded body and the male mold, which is disposed near the mold release device of the male mold and is released by the mold release device. An injection molding apparatus comprising: In the injection molding device according to any one of claims 1 to 3 ,
The injection molding apparatus, wherein the air is cooled air. In the injection molding apparatus according to any one of claims 1 to 4 ,
The cavity is
A first cavity portion having a hollow cylindrical shape;
A second cavity portion having a ring shape along a conical surface, wherein one end is connected to the first cavity portion, and the normal line in the ring shape is inclined so as to intersect outside the hollow molded body. A second cavity portion,
A third cavity part having a ring shape in which one end is connected to the other end of the second cavity part and the outside is formed with a convex curved surface;
A fourth cavity portion having a hollow cylindrical shape connected to the other end of the third cavity portion and forming an outermost side wall of the hollow molded body;
An injection molding apparatus comprising: An injection molding method,
(1) a step of forming a hollow molded body in the cavity by injecting and injecting a resin into a cavity of a mold having a female mold and a male mold;
(2) opening the mold;
(3) a step of moving the push-up core disposed on the top of the male mold in the direction of the top while rotating ;
(4) a step of blowing air into a gap formed between the hollow molded body and the male mold when the pushed-up core pushes up the hollow molded body;
An injection molding method comprising:

Images