JP2007152655A - Injection molding machine, in-mold nozzle and mold used in injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a molten resin in the resin passage of a mold to be melted and to prevent the molten resin in the resin passage from flowing back outside the mold even when a resin injection unit is separated from the mold. <P>SOLUTION: An injection molding machine 66 is equipped with the mold 30, an in-mold nozzle 50 fitted to the mold 30, and an external nozzle 70c supplying the molten resin to the in-mold nozzle 50. The in-mold nozzle 50 has a resin inlet 50b connected with the external nozzle 70c, a resin outlet 50a opened to a cavity, a nozzle body 51 having the resin passage 50c making the resin inlet and the resin outlet communicate with each other, and an opening/closing valve 56 which is arranged in the resin passage 50c, opens the resin inlet 50b when the pressure of the outside of the resin inlet 50b is higher than the pressure of the molten resin in the resin passage 50c and closes the resin inlet 50b when the pressure of the outside of the resin inlet 50b is lower than the pressure of the molten resin in the resin passage 50c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an injection molding apparatus that molds a molded product by injecting molten resin into a cavity.

As a conventional injection molding apparatus, the one disclosed in Patent Document 1 is known. The injection molding apparatus disclosed in Patent Document 1 includes a molding die and a resin injection unit that injects molten resin into the molding die. The mold includes a cavity having a shape corresponding to the shape of the molded product, and a molten resin flow path that guides the molten resin to the cavity. The resin injection unit includes a nozzle for injecting molten resin into the molten resin flow path.
In this injection molding apparatus, the nozzle of the resin injection unit is brought into contact with one end of the molten resin flow path of the mold, and the molten resin is injected from the nozzle into the molten resin flow path. The molten resin injected from the nozzle is injected into the cavity through the molten resin flow path, whereby the cavity is filled with the molten resin. When the cavity is filled with molten resin, the filled molten resin is cooled and solidified to form a molded product. When the molten resin injected into the cavity is solidified, the nozzle of the resin injection unit is cut off from the molten resin flow path of the mold, the mold is opened, and the molded product is taken out.
Japanese Patent Laid-Open No. 3-197115

In the above-described injection molding apparatus, the cavity is filled with the molten resin through the molten resin flow path. For this reason, when the molten resin is filled in the cavity, the molten resin flow path is also filled with the molten resin. For this reason, when the molten resin in the cavity is cooled and solidified, the molten resin in the molten resin flow path is also cooled and solidified. When the molten resin in the molten resin flow path is solidified, an operation for removing the resin in the molten resin flow path is required to form the next molded product. Therefore, it is necessary to design the mold in consideration of the removal operation of the resin solidified in the molten resin flow path, and the route of the molten resin flow path is limited. Therefore, development of an injection molding apparatus that does not solidify the molten resin in the molten resin flow path when cooling the molten resin in the cavity has been studied.
However, if the resin in the molten resin channel is not solidified, there is a problem that the resin in the resin channel flows backward from the resin injection port when the resin injection unit is separated from the mold. That is, when the cavity is filled with the molten resin, the molten resin is injected at a high pressure from the resin injection unit, so the pressure of the molten resin in the molten resin flow path is also high. For this reason, if the resin injection unit is separated from the mold (that is, the molten resin flow path), there arises a problem that the molten resin in the molten resin flow path flows back to the outside of the mold.

  The present invention has been made in view of the above-described circumstances, and can maintain the molten resin in the molten resin flow path of the mold in a molten state, and the molten resin flow even if the resin injection unit is separated from the mold. Provided is a technique capable of preventing a molten resin in a passage from flowing backward to the outside of a mold.

The injection molding apparatus of the present invention includes a mold main body having a cavity and an in-mold nozzle attached to the mold main body. An external nozzle for injecting the molten resin is connected to the in-mold nozzle. The molten resin supplied from the external nozzle is injected into the cavity of the mold body through the in-mold nozzle.
The in-mold nozzle includes a nozzle body and an opening / closing valve accommodated in the nozzle body. The nozzle body has a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow path that connects the resin inlet and the resin injection port. The on-off valve opens the resin inlet when the pressure outside the resin inlet is higher than the pressure of the molten resin inside the resin passage, and the pressure outside the resin inlet is lower than the pressure of the molten resin inside the resin passage. In some cases, the resin inlet is closed.
In the injection molding apparatus of the present invention, molten resin is injected from an external nozzle into an in-mold nozzle of a mold, and the injected molten resin is injected into a mold cavity through the in-mold nozzle. Since the molten resin is guided to the cavity by a nozzle in the mold separate from the mold body, the nozzle in the mold can be made difficult to be cooled even when the mold body is cooled to cool the molten resin in the cavity. . For this reason, the molten resin in the in-mold nozzle can be maintained in a molten state.
In addition, an on-off valve is provided at the resin inlet of the in-mold nozzle. When filling the mold cavity with molten resin, the pressure outside the resin inlet is higher than the pressure of the molten resin in the mold nozzle. Therefore, the on-off valve opens the resin inlet, and the molten resin can be injected from the external nozzle into the in-mold nozzle. On the other hand, when the external nozzle is separated from the molding die, the pressure outside the resin inlet becomes lower than the pressure of the molten resin in the resin flow path, so the on-off valve closes the resin inlet. Therefore, even if the external nozzle is separated from the mold, the molten resin in the resin flow channel does not overflow from the resin inlet.

In the above injection molding apparatus, it is preferable that the on-off valve is movable between a first position where the resin inlet is opened and a second position where the resin inlet is closed. In this case, when the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin flow path, the on-off valve moves to the first position due to the pressure difference, and the pressure of the molten resin in the resin flow path When the pressure outside the resin inlet is lower, it is preferable that the on-off valve is moved to the second position due to the pressure difference.
According to such a configuration, the on-off valve moves due to the pressure difference between the molten resin in the resin flow path and the pressure outside the resin inflow port, so the structure of the on-off valve can be simplified.

The above-mentioned in-mold nozzle further has a valve for opening and closing the resin injection port, and the valve is preferably controlled to be opened and closed by an external control device.
According to such a configuration, when the molten resin in the cavity is solidified, the resin injection port is closed by the valve, and the resin flow path between the cavity and the in-mold nozzle can be shut off. For this reason, it is possible to prevent the molten resin in the in-mold nozzle from being cooled, and it is possible to prevent the molten resin in the in-mold nozzle from flowing out to the cavity side when the molded product is taken out from the mold.

  In addition, a heater can be disposed around the above-mentioned in-mold nozzle. By disposing a heater around the in-mold nozzle, the resin in the in-mold nozzle can be easily maintained in a molten state even when the molten resin in the cavity is cooled.

Further, in the above injection molding apparatus, since the molding die body and the in-mold nozzle are combined to form a molding die, the resin flow path of the in-mold nozzle can be bent. If the resin flow path of the in-mold nozzle can be bent, the degree of freedom in designing the injection position of the molten resin into the cavity can be increased.
In this case, the mold main body is formed with a space in a portion adjacent to the bent portion of the in-mold nozzle and facing the resin inlet, and a pressure receiving block can be arranged in the space. The pressure receiving block preferably has a pressure receiving surface that comes into contact with the in-mold nozzle.
According to such a configuration, when the external nozzle is brought into contact with the in-mold nozzle, an external force acting on the in-mold nozzle from the external nozzle can be received by the pressure receiving block. For this reason, it is possible to prevent an excessive force from acting on the in-mold nozzle, and it is possible to prevent damage to the in-mold nozzle.

The present invention also provides an in-mold nozzle for injection molding that can solve the above problems. That is, the in-mold nozzle of the present invention is mounted in the mold so that the external nozzle can come into contact, and injects molten resin supplied from the external nozzle into the cavity. This in-mold nozzle includes a nozzle body having a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin channel that communicates the resin inlet and the resin injection port, and a resin channel When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin channel, the resin inlet is opened, and the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin channel. An opening / closing valve that closes the resin inlet when it is low is provided.
Even with this in-mold nozzle, the resin in the mold nozzle can be maintained in a molten state when the molten resin in the cavity is cooled, and even if the external nozzle is disconnected from the in-mold nozzle, the molten resin in the mold nozzle remains outside. It is possible to prevent outflow.

The present invention also provides a mold for injection molding that can solve the above-mentioned problems. That is, the molding die of the present invention is a molding die for molding a molded product by injecting molten resin supplied from an external nozzle into a cavity. This mold includes a mold body and an in-mold nozzle attached to the mold body.
The in-mold nozzle includes a nozzle body having a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow channel that connects the resin flow inlet and the resin injection port. When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin channel, the resin inlet is opened, and the pressure outside the resin inlet is lower than the pressure of the molten resin in the resin channel. And an on-off valve that closes the resin inlet.
Even with this mold, when the molten resin in the cavity is cooled, the resin in the nozzle in the mold can be maintained in a molten state, and even if the external nozzle is disconnected from the nozzle in the mold, the molten resin in the mold nozzle remains outside. It is possible to prevent outflow.

Furthermore, the present invention provides a molding die that can prevent deformation and breakage of the in-mold nozzle when the molding die body is combined with a bent in-mold nozzle to form a molding die. That is, when a bent in-mold nozzle is attached to the molding die body, the processing accuracy of the bending portion of the in-mold nozzle and the mounting portion of the molding die body tends to deteriorate, and the bending portion of the in-mold nozzle and the mounting portion of the molding die body There will be a gap between them. When the external nozzle is brought into contact with the in-mold nozzle in such a mounting state, the in-mold nozzle is deformed in the mounting portion of the molding die body by an external force acting on the in-mold nozzle from the external nozzle, and the bent portion of the in-mold nozzle And the inner wall of the mounting portion of the mold body are in partial contact. For this reason, external force that acts on the nozzle in the mold from the external nozzle is received in a narrow area where the bent part of the nozzle in the mold and the mounting part of the mold main body come into contact with each other. Occurs.
Accordingly, the molding die of the present invention is a molding die for molding a molded product by injecting molten resin supplied from an external nozzle into a cavity, and a die attached to the molding die body. An inner nozzle is provided. The in-mold nozzle is attached to the mold body and has a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow path that connects the resin inlet and the resin injection port. ing. The in-mold nozzle is bent, and a space is formed in a portion of the mold body adjacent to the bent portion of the in-mold nozzle and facing the resin inlet, and a pressure receiving block is formed in the space. The pressure receiving block has a pressure receiving surface that comes into contact with the in-mold nozzle.
The pressure receiving block is smaller than the mold main body and can be precisely processed. For this reason, the pressure receiving block can be precisely processed according to the gap between the mold body and the nozzle in the mold. If the pressure receiving block is precisely processed, when the in-mold nozzle is attached to the molding die body, the in-mold nozzle and the pressure receiving surface of the pressure receiving block can be brought into close contact with each other without any gap. Therefore, in this mold, when the external nozzle is brought into contact with the in-mold nozzle, an external force acting on the in-mold nozzle from the external nozzle can be received by the pressure receiving surface of the pressure receiving block. For this reason, it is possible to prevent an excessive force from acting on the in-mold nozzle, and it is possible to prevent damage to the in-mold nozzle.

The main features of the embodiments described in detail below are listed first.
(Embodiment 1) The injection molding apparatus includes a mold and a resin supply unit that supplies molten resin to the mold. The mold includes a plurality of resin flow paths that guide the resin to the cavity. The resin supply unit includes a plurality of external nozzles that supply resin to a plurality of resin flow paths.
(Mode 2) The mold is constituted by a female mold and a male mold that moves forward and backward with respect to the female mold. The mold is closed when the male mold comes into contact with the female mold, and the mold is opened when the male mold is separated from the female mold.
(Mode 3) The female mold has a front cavity surface for molding the surface of the molded product. The male mold has a back cavity surface for molding the back surface of the molded product. When the mold is closed, a cavity is formed by the front cavity surface and the back cavity surface.
(Mode 4) A resin flow path is formed on a surface (parting surface) where the female mold and the male mold come into contact. The resin flow path is constituted by a groove formed on the contact surface of the female mold and the contact surface of the male mold. When the mold is closed, a resin flow path is formed by the groove of the female mold and the contact surface of the male mold, and one end of the resin flow path opens into the cavity.
(Mode 5) The female die is provided with an attachment hole penetrating from the surface of the female die to the front cavity surface. The mounting hole is bent in the female mold. One end of the mounting hole opens in the front cavity surface of the female mold, and the other end of the mounting hole opens in the upper surface of the female mold.
(Mode 6) An in-mold nozzle is attached to an end of the attachment hole on the front cavity surface side. The in-mold nozzle is bent according to the shape of the mounting hole. The other end of the mounting hole serves as an insertion path for an external nozzle. When the external nozzle is inserted into the other end of the mounting hole, the tip of the external nozzle is connected to the in-mold nozzle.
(Mode 7) The in-mold nozzle includes a nozzle body, an on-off valve, and a valve gate. The nozzle body has a resin inflow port, a resin injection port that opens into the cavity, and a resin flow path that connects the resin inflow port and the resin injection port. The molten resin injected from the resin supply unit to the resin inflow port is injected from the resin injection port into the cavity through the resin flow path.
(Mode 8) The on-off valve is disposed in the resin flow path of the nozzle body, and is movable between a first position for opening the resin inlet and a second position for closing the resin inlet. The on-off valve has a pressure receiving fin. The on-off valve moves between the first position and the second position due to the pressure difference between the upstream and downstream resins.
(Mode 9) The valve gate is controlled by the control device, and opens and closes the resin injection port of the nozzle body.
(Mode 10) The female mold has a heater. The heater is arranged around the nozzle in the mold.
(Mode 11) In the female die, a space is formed at a portion adjacent to the bent portion of the mounting hole and facing the external nozzle insertion end of the mounting hole. A pressure receiving block is disposed in this space. The pressure receiving block has a pressure receiving surface. The pressure receiving surface is a bent portion of the in-mold nozzle and is in close contact with the outer surface of the portion facing the resin inlet without any gap. The pressure receiving block is made of a material harder than the mold.

An injection molding apparatus 66 according to an embodiment of the present invention will be described with reference to the drawings. First, before describing the injection molding apparatus 66, a molded product molded by the injection molding apparatus 66 will be described. FIG. 1 is a perspective view showing an example of a molded product 10 molded by the injection molding device 66.
A molded product 10 shown in FIG. 1 is a resin bumper for automobiles. The molded product 10 includes a front part 12 and side parts 11 and 13 formed at both ends of the front part 12. Through holes 16 and 18 are formed in the front portion 12. By forming the through holes 16, 18, the upper front part 20 is at the upper part of the through hole 16, the lower front part 24 is at the lower part of the through hole 18, and the middle front part 22 is between the through hole 16 and the through hole 18. Each is formed.
Reference numerals 26a, 26b, and 26c in FIG. 1 indicate molten resin injection paths when the molded product 10 is injection-molded. Injection paths 26 a, 26 b, and 26 c are provided in the upper front portion 20, the medium-small surface portion 22, and the lower front portion 24, respectively. The reason why the injection paths 26a, 26b, and 26c are provided in each of the front sections 20, 22, and 24 is that the resin injected into the upper front section 20 and the lower front section 24 only when the injection paths 26a and 26c are provided. This is because it has to flow around the through holes 16 and 18 to the middle front part 22 and it is difficult to fill the middle front part 22 with resin.
In addition, the injection molding apparatus 66 of the present embodiment can mold various parts (for example, parts (dashboard etc.) to be assembled in an automobile etc.) other than the automobile bumper shown in FIG. Further, as will be described later, the injection molding apparatus 66 of the present embodiment can provide an injection path at a location that has been difficult in the prior art, so a large molded product that is difficult to fill with a molten resin or a complex molded product. Suitable for molding products.

  Next, the configuration of the injection molding apparatus 66 will be described. FIG. 2 is a cross-sectional view schematically showing the injection molding apparatus of the present embodiment, showing a cross section at a position corresponding to the line II-II of the molded product 10 of FIG. FIG. 3 is a plan view of the injection molding device 66. As shown in FIGS. 2 and 3, the injection molding apparatus 66 includes a mold 30, external nozzles 70 a to 70 c that inject molten resin into the mold 30, an injection machine 82 that supplies molten resin to the external nozzle, A drive device 84 that opens and closes the mold 30 and a control device 80 that controls each part of the injection molding device 66 are provided.

  The mold 30 includes a female mold 34 and a male mold 32 that moves forward and backward with respect to the female mold 34 by the driving device 84. When the drive device 84 moves the male mold 32 toward the female mold 34, the male mold 32 and the female mold 34 come into contact with each other and the mold 30 is closed. When the driving device 84 moves the male mold 32 away from the female mold 34, the mold 30 is opened. The driving device 84 is controlled by the control device 80.

  The male mold 32 has a cavity surface 33 for molding the back surface of the molded product 10. The cavity surface 33 is formed on the surface of the male mold 32 that faces the female mold 34. The cavity surface 33 is formed in a shape corresponding to the back surface of the molded product 10. That is, the cavity surface 33 a corresponds to the back surface of the upper front portion 20 of the molded product 10, the cavity surface 33 b corresponds to the back surface of the middle front portion 22 of the molded product 10, and the cavity surface 33 c corresponds to the lower front portion 24 of the molded product 10. Each is formed in a shape corresponding to the back surface.

The female die 34 has a cavity surface 35 for molding the surface of the molded product 10. The cavity surface 35 is formed on the surface where the female mold 34 faces the male mold 32. The cavity surface 35 is formed in a shape corresponding to the surface of the molded product 10. That is, the cavity surface 35a corresponds to the surface of the upper front portion 20 of the molded product 10, the cavity surface 35b corresponds to the surface of the middle front portion 22 of the molded product 10, and the cavity surface 35c corresponds to the lower front portion 24 of the molded product 10. Each is formed in a shape corresponding to the surface.
Therefore, when the male mold 32 is moved toward the female mold 34 and the mold 30 is closed, a cavity 44 is formed by the cavity surface 33 of the male mold 32 and the cavity surface 35 of the female mold 34. The shape of the cavity 44 corresponds to the shape of the molded article 10. That is, the shape of the cavity 44 a corresponds to the shape of the upper front portion 20 of the molded product 10, the shape of the cavity 44 b corresponds to the shape of the middle front portion 22 of the molded product 10, and the shape of the cavity 44 c is lower than the molded product 10. This corresponds to the shape of the front portion 24.

A resin flow path 36 and a resin flow path 38 are formed on the surface where the female mold 34 and the male mold 34 abut. The resin flow path 36 communicates the upper surface of the mold 30 and the cavity 44a. The resin flow path 36 is formed by a groove 36 b formed on the contact surface of the female mold 34 and the contact surface of the male mold 34. A nozzle touch 36 c is provided at the upstream end of the resin flow path 36, and a gate 36 a is provided at the downstream end of the resin flow path 36. The resin flow path 36 corresponds to the injection path 26a in FIG.
The resin flow path 38 communicates the lower surface of the mold 30 and the cavity 44c. Similar to the resin flow path 36, the resin flow path 38 is formed by a groove 38 b formed on the contact surface of the female mold 34 and a contact surface of the male mold 34. A nozzle touch 38 c is provided at the upstream end of the resin flow path 38, and a gate 38 a is provided at the downstream end of the resin flow path 38. The resin flow path 36 corresponds to the injection path 26c in FIG.

The female mold 34 is provided with a mounting hole 34a that allows the upper surface of the female mold 34 to communicate with the cavity 44b. The mounting hole 34a extends substantially vertically downward from the upper surface of the female die 34, bends substantially at a right angle at a position corresponding to the cavity 44b, and extends to the cavity 44b. An in-mold nozzle 50 (described later) is attached to the end of the mounting hole 34a on the cavity 44b side, and the other end of the mounting hole 34a opens to the front cavity surface of the female mold, and the insertion path of the external nozzle 70c Become.
Further, in the female die 34, an accommodation space 34b is formed at a position adjacent to the bent portion of the mounting hole 34a. The accommodation space 34b is formed below the attachment hole 34a (that is, a position facing the end of the attachment hole 34a on the insertion side of the external nozzle 70c). A pressure receiving block 60 is accommodated in the accommodating space 34b.

  Next, the in-mold nozzle 50 and the pressure receiving block 60 will be described with reference to FIGS. 4 and 5 are enlarged views of the in-mold nozzle 50 and its surroundings. FIG. 4 shows a state in which molten resin is injected from the external nozzle 70c to the in-mold nozzle 50, and FIG. The state separated from the inner nozzle 50 is shown. 6 is a cross-sectional view at a position corresponding to line VI-VI in FIG. As shown in the figure, the in-mold nozzle 50 is attached to the end of the mounting hole 34a of the female die 34 on the cavity 44b side so as not to move. The in-mold nozzle 50 includes a nozzle body 51, an on-off valve 56, and a valve gate 52.

The nozzle body 51 is bent at about 90 degrees according to the shape of the mounting hole 36a. The nozzle body 51 includes a horizontal portion 51a disposed on the cavity 44b side, and a vertical portion 51b provided substantially perpendicular to the horizontal portion 51a. A nozzle touch 54 is formed at the upper end of the vertical portion 51b. An external nozzle 70c is detachably connected to the nozzle touch 54. A resin inlet 50 b is formed at the center of the nozzle touch 54.
A horizontal portion 51a is connected to the lower end of the vertical portion 51b. A resin injection port 50a that opens to the cavity 44b is formed at the tip of the horizontal portion 51a. In the nozzle main body 51, a resin flow path 50c that communicates the resin inflow port 50b and the resin injection port 50a is provided. A resin reservoir 50e is formed at a portion adjacent to the resin inlet 50b of the resin flow path 50c.

  An open / close valve 56 is accommodated in the resin reservoir 50e so as to be slidable in the vertical direction. The on-off valve 56 includes a plug portion 56b that opens and closes the resin inlet 50b, and a plurality of pressure receiving fins 56a that extend radially from the plug portion 56b (see FIG. 6). Resin pressure on the upstream side (resin inlet 50b side) and resin pressure on the downstream side (resin injection port 50a side) act on the pressure receiving fin 56a, and the opening / closing valve 56 moves up and down in the resin reservoir 50e by the pressure difference. Slide in the direction. That is, the on-off valve 56 slides between the position shown in FIG. 4 (first position in the claims) and the position shown in FIG. 5 (second position in the claims). When the resin pressure upstream of the on-off valve 56 is high, the on-off valve 56 moves to the first position. For this reason, a gap is formed between the plug portion 56b and the resin inlet 50b, and the on-off valve 56 opens the resin inlet 50b. On the other hand, when the resin pressure on the downstream side of the on-off valve 56b is high, the on-off valve 56 moves to the second position. For this reason, the plug part 56b seals the resin inlet 50b, and the on-off valve 56 closes the resin inlet 50b.

  The valve gate 52 is attached to the nozzle body 51. The valve gate 52 is an electromagnetic on-off valve that opens and closes the resin injection port 50a. When the energization of the valve gate 52 is turned on, the resin injection port 50a is opened, and when the energization is turned off, the resin injection port 50a is closed. Opening / closing control of the valve gate 52 is performed by the control device 80. In a state where the external nozzle 70c is not connected to the in-mold nozzle 50, the valve gate 52 closes the resin injection port 50a as will be described in detail later. If the molten resin remains in the resin flow path 50c and the resin reservoir 50e in this state, the pressure on the downstream side of the pressure receiving fins 56a increases, so the on-off valve 56 moves to the second position and the resin inlet 50b is closed.

  A heater 64 is attached around the in-mold nozzle 50. The heater 64 heats the molten resin in the in-mold nozzle 50. For this reason, the molten resin in the in-mold nozzle 50 is held in a molten state and does not solidify. The heater 64 is also turned on / off by the control device 80. In FIG. 3, the heater 64 is not shown in consideration of easy viewing.

  The pressure receiving block 60 is accommodated in the accommodating space 34 b of the female die 34. The pressure receiving block 60 is precisely processed so that there is no gap between the in-mold nozzle 50 and the female die 34 when the pressure receiving block 60 is accommodated in the accommodating space 34b. For this reason, when the pressure receiving block 60 is accommodated in the accommodating space 34b, the lower surface 50d of the bent portion of the in-mold nozzle 50 (hereinafter also referred to as the pressure receiving surface 50d of the in-mold nozzle 50) and the upper surface 60d (hereinafter referred to as the pressure receiving block 60). , Also referred to as a pressure receiving surface 60d of the pressure receiving block 60).

  The external nozzle 70a is connected to the resin injection machine 82, and injects the pressurized molten resin supplied from the resin injection machine 82 from the tip. The external nozzle 70a can be moved in the vertical direction in FIG. 2 by a driving device (not shown). When the external nozzle 70a is moved toward the nozzle touch 36c, the tip of the external nozzle 70a comes into contact with the nozzle touch 36c, and the external nozzle 70a and the nozzle touch 36c are connected. When the external nozzle 70a is moved away from the nozzle touch 36c, the tip of the external nozzle 70a and the nozzle touch 36c are separated. When the molten resin is injected from the external nozzle 70a in a state where the external nozzle 70a is connected to the nozzle touch 36c, the injected molten resin is injected into the resin flow path 36 and is injected from the gate 36a into the cavity 44a.

  The external nozzle 70b is also connected to the resin injection machine 82, and injects the pressurized molten resin supplied from the resin injection machine 82 from the tip. The external nozzle 70b is also driven by a driving device (not shown) and is connected to or disconnected from the nozzle touch 38c. When the molten resin is injected from the external nozzle 70b in a state where the external nozzle 70b is connected to the nozzle touch 38c, the molten resin is injected into the resin flow path 38 and is injected from the gate 38a into the cavity 44c.

  The external nozzle 70c is also connected to the resin injection machine 82, and injects the pressurized molten resin supplied from the resin injection machine 82 from the tip. The external nozzle 70c is also driven by a driving device (not shown), and the external nozzle 70c can be separated from the state where it is connected to the nozzle touch 54 of the in-mold nozzle 50. That is, the external nozzle 70c is inserted into the mounting hole 34a from above, the tip of the external nozzle 70c and the nozzle touch 54 are brought into contact, and the external nozzle 70c and the in-mold nozzle 50 are connected. The external nozzle 70c can be pulled out from the mounting hole 34a, and the external nozzle 70c and the in-mold nozzle 50 can be separated.

Here, the operation of the external nozzle 70c and the in-mold nozzle 50 during injection molding will be briefly described. In a state where the external nozzle 70c is disconnected from the nozzle touch 54, the valve gate 52 closes the resin injection port 50a as described above. For this reason, the resin flow path 50c of the in-mold nozzle 50 is filled with molten resin, and when the pressure of the molten resin is high, the on-off valve 56 is in the second position and closes the resin inlet 50b.
In order to supply the molten resin to the cavity 44b from this state, the external nozzle 70c is connected to the nozzle touch 54, the resin injection port 50a of the in-mold nozzle 50 is opened, and the resin flow of the in-mold nozzle 50 from the external nozzle 70c. Molten resin is injected into the inlet 50b. When the molten resin is injected into the resin inlet 50b, the plug portion 56b of the opening / closing valve 56 receives the pressure of the molten resin injected into the resin inlet 50b, and the opening / closing valve 56 moves from the second position to the first position. The on-off valve 56 slides to open the resin inlet 50b. When the on-off valve 56 opens the resin inlet 50b, the molten resin injected from the external nozzle 70c is injected from the resin injection port 50a into the cavity 44b through the resin flow path 50c. Therefore, the in-mold nozzle 50 corresponds to the injection path 26b of FIG. In the state where the on-off valve 56 is moved to the first position, the pressure of the molten resin from the external nozzle 70c acts on the pressure receiving fins 56a, and the on-off valve 50b is stably held at the first position.
When pressurization of the molten resin from the external nozzle 70c is stopped after the resin is injected into the cavity 44, the molten resin in the resin flow path 50c and the resin reservoir 50e is decompressed but not at atmospheric pressure, and is in a compressed state. Become. When the resin injection port 50a is closed from this state and the external nozzle 70c is disconnected from the nozzle touch 54, the molten resin in the resin flow path 50c and the resin reservoir 50e tends to flow backward from the resin inlet 50b. Since the molten resin flows in the direction of the resin inlet 50b in the resin reservoir 50e, the pressure receiving fins 56a of the on-off valve 56 receive the pressure of the molten resin flowing in the resin reservoir 50e. When the pressure receiving fin 56a receives the pressure of the molten resin, the on-off valve 56 slides from the first position to the second position. When the on-off valve 56 slides to the second position, the plug portion 56b of the on-off valve 50 closes the resin inlet 50b. When the resin inlet 50b is closed, the on-off valve 56 is held in a state of being pressed toward the resin inlet 50b by the pressure of the molten resin in the mold nozzle 50. Thereby, the in-mold nozzle 50 returns to the state before the resin injection.

An injection molding method using the injection molding apparatus 66 will be described with reference to FIG. FIG. 7 is a process diagram when the molded product 10 is injection-molded by the injection molding device 66.
As shown in FIG. 7, first, the male mold 32 is moved toward the female mold 34 by the driving device 84, the male mold 32 and the female mold 34 are brought into contact with each other, and the mold 30 is closed (mold closing). Process). During the mold closing process, the external nozzles 70 a to 70 c are not connected to the mold 30. In the mold nozzle 50, the valve gate 52 closes the resin injection port 50a, and the on-off valve 56 closes the resin inflow port 50b.
Note that a release agent may be applied to the cavity surface 33 of the male mold 32 and the cavity surface 35 of the female mold 34 before performing the mold clamping process. By applying a release agent to the cavity surfaces 33 and 35, the molded product 10 can be easily taken out from the mold 30 in a molded product take-out process described later.

When the mold 30 is closed by the mold clamping process, the external nozzles 70a, 70b, 70c are connected to the mold 30, respectively, and the molten resin is injected from the external nozzles 70a, 70b, 70c into the cavity 44 of the mold 30 (injection process). ).
That is, the valve gate 52 is driven to open the resin injection port 50a. When the resin injection port 50a is opened, the external nozzles 70a, 70b, 70c are connected to the nozzle touches 36c, 38c, 54, respectively. At this time, the external nozzles 70a, 70b, 70c are pressed and connected to the nozzle touches 36c, 38c, 54 with a predetermined pressure so that the molten resin does not leak from the respective connecting portions. Here, the pressure for pressing the external nozzle 70 c against the nozzle touch 54 is applied between the pressure receiving surface 50 d of the in-mold nozzle 50 and the pressure receiving surface 60 a of the pressure receiving block 60. Since the pressure receiving surface 60a and the pressure receiving surface 50d are in close contact with each other without any gap, deformation of the in-mold nozzle 50 is suppressed.
When the external nozzles 70a, 70b, 70c and the nozzle touches 36c, 38c, 54 are connected, molten resin is injected from the external nozzles 70a, 70b, 70c, respectively, at a predetermined pressure (about 40 MPa in this embodiment). The molten resin injected from the external nozzle 70a passes through the resin flow path 36b and is injected from the gate 36a to the cavity 44a. The molten resin injected from the external nozzle 70b passes through the resin flow path 38b and is injected from the gate 38a to the cavity 44c. The molten resin injected from the external nozzle 70c is injected into the resin inflow port 50b. When the molten resin is injected into the resin inlet 50b, as described above, the on-off valve 56 slides from the second position to the first position, and opens the resin inlet 56b. Therefore, the molten resin from the external nozzle 70c is injected into the cavity 44b from the resin injection port 50a through the resin flow path 50c (state shown in FIG. 3).

When the cavity 44 is filled with the molten resin, pressure is continuously applied to the molten resin from the external nozzles 70a, 70b, and 70c, and the mold 30 is cooled (pressure holding process, cooling process). When the mold 30 is cooled, the molten resin filled in the cavity 44 is cooled. When the molten resin in the cavity 44 is appropriately cooled, the application of pressure to the molten resin from the external nozzles 70a, 70b, and 70c is stopped. When the pressure on the molten resin is stopped, the resin injection port 50a is closed by the valve gate 52. When the resin injection port 50 a is closed, the molten resin in the cavity 44 is further cooled and solidified to obtain a molded product 10.
When the molten resin filled in the cavity 44 is cooled, the heater 64 is turned on to heat the in-mold nozzle 50 from the surroundings. For this reason, the molten resin in the in-mold nozzle 50 is prevented from being cooled and solidified. On the other hand, the molten resin in the resin flow paths 36 and 38 is cooled and solidified when the molten resin filled in the cavity 44 is cooled.

  When the molten resin in the cavity 44 is sufficiently cooled to become the molded product 10, next, the external nozzles 70 a, 70 b and 70 c are separated from the mold 30 and the mold 30 is opened (mold opening process). That is, the external nozzles 70a, 70b, and 70c are separated from the nozzle touches 36c, 38c, and 54, respectively. Even when the external nozzle 70a is separated from the nozzle touch 36c, the molten resin in the resin flow path 36 is solidified, so that the molten resin in the resin flow path 36 does not overflow to the outside of the mold 30. Similarly, even if the external nozzle 70a is separated from the nozzle touch 36c, the molten resin in the resin flow path 38 is solidified, and the molten resin in the resin flow path 38 does not overflow to the outside of the mold 30. Further, as described above, since the molten resin in the in-mold nozzle 50 is heated by the heater to maintain the molten state, when the external nozzle 70c is separated from the nozzle touch 54, the molten resin in the in-mold nozzle 50 is removed. An attempt is made to back flow from the resin inlet 50b to the outside. However, since the on-off valve 56 slides from the first position to the second position to close the resin inlet 50b, the molten resin in the mold nozzle 50 does not overflow from the resin inlet 50b (state shown in FIG. 4). . When the external nozzles 70a, 70b, and 70c are separated from the mold 30, the male mold 32 is moved away from the female mold 34 by the driving device 84 to open the mold 30.

  When the mold 30 is opened, the molded product 10 is removed from the mold 30 (molded product extraction step). In the molded product removal step, the molded product 10 is taken out, and at the same time, the solidified resin remaining in the resin flow paths 36 and 38 is taken out. Since the resin flow paths 36 and 38 are formed on the contact surface (parting surface) between the male mold 32 and the male mold 32, the resin solidified in the resin flow paths 36 and 38 is used as the mold 30. When opened, it can be easily removed.

As is clear from the above description, in the injection molding apparatus 66 of the present embodiment, the molten resin in the in-mold nozzle 50 is not solidified even after the cooling step. Therefore, it is not necessary to remove the resin in the in-mold nozzle 50 after the injection molding, and it is possible to proceed to the next injection molding process as it is. Further, since it is not necessary to remove the resin in the in-mold nozzle 50, the in-mold nozzle 50 can be bent, and an injection path that cannot be provided conventionally can be provided.
Further, the in-mold nozzle 50 of the above-described embodiment includes an on-off valve 56. The on-off valve 56 prevents the molten resin in the in-mold nozzle 50 from overflowing from the resin inlet 50b when the external nozzle 70c is separated from the nozzle touch 54. Further, the on-off valve 56 has a simple structure because it slides between the first position and the second position due to the pressure difference between the molten resin in the mold nozzle 50 and the pressure outside the resin inlet 50b. ing.
Further, the in-mold nozzle 50 of the above-described embodiment has a valve gate 52 that opens and closes the resin injection port 50a. With such a configuration, when the molten resin in the cavity 44 is solidified, the resin injection port 50 a is closed to block the cavity 44 b and the resin flow path 50 c of the in-mold nozzle 50. For this reason, it is possible to prevent the molten resin in the in-mold nozzle 50 from being cooled. Further, when the molded product 10 is taken out from the mold 30, it is possible to prevent the molten resin in the mold nozzle 50 from flowing into the cavity 44 b.
Further, a heater is disposed around the in-mold nozzle 50 of the above-described embodiment. Thereby, when the molten resin in the cavity 44 is cooled, the resin in the in-mold nozzle 50 can be easily maintained in a molten state.
In the embodiment described above, the pressure receiving block 60 receives the force acting on the in-mold nozzle 50 from the external nozzle 70c. The pressure receiving block 60 is in close contact with the in-mold nozzle 50 without any gap, and deformation of the in-mold nozzle 50 is suppressed. Thereby, damage to the nozzle in the mold can be prevented.

In the injection molding apparatus 66 of the above-described embodiment, the in-mold nozzle 50 is bent at about 90 degrees, but the present invention is not limited to such a form, and the shape of the cavity 44 (that is, the shape of the molded product). ), The in-mold nozzle 50 can be arbitrarily bent (for example, bent in an arc shape, bent at two or more locations).
In the injection molding apparatus 66 of the above-described embodiment, the on-off valve 56 is moved between the first position and the second position by the pressure difference between the molten resin in the mold nozzle 50 and the pressure outside the resin inlet 50b. However, the present invention is not limited to such a form. For example, a valve gate that can be controlled by the control device 80 may be further provided in the in-mold nozzle 50, and the resin inlet 50b may be opened and closed by the valve gate. When the pressure outside the resin inlet 50b is higher than the pressure of the molten resin in the mold nozzle 50 (that is, the injection process and the pressure holding process), this valve gate is operated by the control device 80 and the resin flow. When the inlet 50b is opened and the pressure outside the resin inflow port 50b is lower than the pressure of the molten resin in the mold nozzle 50 (that is, the mold closing process, the mold opening process, and the molded product removal process), the control device 80 To close the resin inlet 50b. Also with this configuration, the molten resin in the in-mold nozzle 50 can be prevented from overflowing from the resin inflow port 50b.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which looked at an example of the molded product shape | molded with the injection molding apparatus of a present Example. The schematic sectional drawing of the injection molding apparatus of an Example. The schematic plan view of the injection molding apparatus of an Example. The expanded sectional view of the nozzle in a model of an example. The expanded sectional view of the nozzle in a model of an example. The expanded sectional view of the nozzle in a model of an example. Process drawing when molding with the injection molding device of the example

Explanation of symbols

10: Molded article 11: Side part 12: Front part 13: Side part 16: Through hole 18: Through hole 20: Upper front part 22: Middle front part 24: Lower front part 26a, 26b, 26c: Injection path 30: Gold Mold 32: Male mold 33: Cavity surfaces 33a, 33b, 33c: Cavity surface 34: Female mold 34a: Mounting hole 34b: Storage space 35: Cavity surfaces 35a, 35b, 35c: Cavity surface 36: Resin flow path 36a: Gate 36b: Resin channel 36c: Nozzle touch 38: Resin channel 38a: Gate 38b: Resin channel 38c: Nozzle touch 44: Cavity 44a, 44b, 44c: Cavity 50: In-mold nozzle 50a: Resin injection port 50b: Resin Inlet 50c: Resin flow path 50d: Pressure receiving surface 50e: Resin reservoir 51: Nozzle body 51a: Horizontal portion 51b: Vertical portion 52: Valve gate 54: Nozzle Touch 56: on-off valve 56a: pressure-receiving fins 56b: stopper portion 60: pressure receiving block 60d: pressure-receiving surface 64: heater 66: injection molding apparatus 70a, 70b, 70c: outer nozzle 80: Control device 82: Injection machine 84: driving device

Claims (8)

An injection molding device that molds a molded product by injecting molten resin into the cavity,
A mold body having a cavity;
An in-mold nozzle attached to the mold body;
An external nozzle that is detachably connected to one end of the nozzle in the mold and supplies molten resin to the nozzle in the mold,
The in-mold nozzle is a nozzle body having a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow path that connects the resin inlet and the resin injection port;
When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin flow path, the resin inlet is opened and outside the resin inlet than the pressure of the molten resin in the resin flow path. And an on-off valve that closes the resin inlet when the pressure is low. The on-off valve is movable between a first position for opening the resin inlet and a second position for closing the resin inlet,
When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin flow path, the opening / closing valve moves to the first position due to the pressure difference, and the resin inlet becomes higher than the pressure of the molten resin in the resin flow path. 2. The injection molding apparatus according to claim 1, wherein the on-off valve moves to the second position due to a difference in pressure when the pressure outside is low.   The injection molding apparatus according to claim 1 or 2, further comprising a valve for opening and closing the resin injection port, the valve being controlled to be opened and closed by an external control device.   The injection molding apparatus according to any one of claims 1 to 3, wherein a heater is disposed around the nozzle in the mold.   The in-mold nozzle is bent, and the molding die body has a space adjacent to the bent portion of the in-mold nozzle and facing the resin inlet, and a pressure receiving block is arranged in the space. 5. The injection molding apparatus according to claim 1, wherein the pressure receiving block has a pressure receiving surface that comes into contact with the in-mold nozzle. An in-mold nozzle that is attached to a molding die in a state where the external nozzle can come into contact, and injects molten resin supplied from the external nozzle into the cavity,
A nozzle body having a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow path that connects the resin inlet and the resin injection port;
When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin flow path, the resin inlet is opened and outside the resin inlet than the pressure of the molten resin in the resin flow path. And an on-off valve that closes the resin inlet when the pressure is low. A molding die for molding a molded product by injecting molten resin supplied from an external nozzle into a cavity,
A mold body,
An in-mold nozzle attached to the mold body,
The nozzle body includes a nozzle body having a resin inlet to which an external nozzle is connected, a resin injection port that opens to the cavity, and a resin flow path that connects the resin inlet and the resin injection port;
When the pressure outside the resin inlet is higher than the pressure of the molten resin in the resin flow path, the resin inlet is opened and outside the resin inlet than the pressure of the molten resin in the resin flow path. And an on-off valve that closes the resin inlet when the pressure is low. A molding die for molding a molded product by injecting molten resin supplied from an external nozzle into a cavity,
A mold body;
An in-mold nozzle having a resin inlet connected to an external nozzle and connected to an external nozzle; a resin injection port opening in the cavity; and a resin flow channel communicating the resin inlet and the resin injection port. Has
The in-mold nozzle is bent, and the mold main body has a space adjacent to the bent portion of the in-mold nozzle and facing the resin inlet, and a pressure receiving block is arranged in the space. And the pressure receiving block has a pressure receiving surface that comes into contact with the nozzle in the mold.

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