JP2022188390A - Injection molding device - Google Patents

Abstract

To provide an injection molding device that can suppress an opening of a mating surface of a cavity and core even when a pressure of molten resin is increased.SOLUTION: An injection molding device 1 includes a cavity 2 and a core 3 that forms a molding space 6 between the cavity 2. The core 3 includes a core body 4 and a core division part 5. The core division part 5 surrounds an entire periphery of the molding space 6 to form part of a face of the molding space 6 and has a mating surface 51 that meets a surface 22 of the cavity 2 in a mold closed state. A passage 75 for introducing molten resin into the molding space 6 is formed on a side surface 52 of the core division part 5 opposite the mating surface 51. The core division part 5 has a first acting surface on which a force acts in a direction away from the cavity 2 due to the molten resin introduced into the molding space 6, and a second acting surface 59 on which a force acts in a direction closer to the cavity 2 due to the molten resin flowing through the passage 75. An area of the second acting surface 59 is set larger than the area of the first acting surface.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to injection molding apparatus.

In injection molding, molten resin is introduced into a molding space formed between a mold cavity and a core, and the molten resin is cooled and solidified to obtain a resin molded body (see, for example, Patent Document 1).

JP 2010-137401 A

In injection molding, the pressure of the molten resin may be increased in order to improve the appearance quality of the resin molded product. However, if the pressure of the molten resin is increased, the mating surface (parting line) between the cavity and the core may be opened, and burrs may be formed in the resin molding. If the pressure of the molten resin is lowered in order to suppress burrs, surface distortion, sink marks, etc. will occur in the resin molding, and the appearance quality will deteriorate.

An object of the present disclosure is to provide an injection molding apparatus capable of suppressing opening of the mating surfaces of the cavity and the core even when the pressure of the molten resin is increased.

The injection molding apparatus of the present disclosure comprises:
a cavity;
a core body that is openable and closable with respect to the cavity and forms a molding space for injection-molding a resin molded body with the cavity when the mold is closed;
is provided on the core body side, surrounds the entire outer periphery of the molding space when viewed from the opening and closing direction of the cavity and the core body, and forms a part of the surface of the molding space, and when the mold is closed, the a core split having a mating surface that mates with the surface of the cavity;
a control unit that separates the core split portion from the core body when the mold is opened after injection molding,
A passage for introducing the molten resin into the molding space is formed on a surface of the core split portion opposite to the mating surface,
The core dividing part is
a first acting surface, which is a surface constituting the molding space and on which a force acts in a direction away from the cavity by the molten resin introduced into the molding space;
and a second acting surface, which is a surface forming the passage and on which a force acts in a direction of approaching the cavity by the molten resin flowing through the passage,
The area of the second working surface is greater than or equal to the area of the first working surface.

According to this, the core forming the molding space with the cavity includes the core main body and the core dividing portion. The core split portion surrounds the entire outer circumference of the molding space and has a mating surface that is mated with the cavity when the mold is closed. Since a passage for introducing the molten resin into the molding space is formed on the surface of the core split portion opposite to the mating surface, the pressure of the molten resin acts on the core split portion in the direction of approaching the cavity. do. Since the area of the second acting surface of the core dividing portion forming the passage is equal to or greater than the area of the first acting surface on which the molten resin exerts a force in the direction away from the cavity, the pressure of the molten resin is increased. Also, opening of the mating surface between the core (core split portion) and the cavity can be suppressed. In addition, since the core split portion is separated from the core body by the control portion when the mold is opened after injection molding, the residual resin remaining between the core split portion and the core body can be taken out.

It is a top view of the core side of an injection molding apparatus. FIG. 2 is a cross-sectional view of the injection molding apparatus taken along line II-II of FIG. 1; 3 is an enlarged view of part A of FIG. 2; FIG. FIG. 2 is a cross-sectional view taken along line IV-IV in FIG. 1, showing a state in which the divided passage portion and the non-divided passage portion are fitted together; FIG. 2 is a cross-sectional view taken along the line VV in FIG. 1, and is a cross-sectional view of the inter-rotating part passage of the molten resin passage. FIG. 2 is a cross-sectional view of a gate conduction passage among the back-side passages formed on the back side of the core division, taken along the line VI-VI in FIG. 1; FIG. 3 is a cross-sectional view of a closed passage out of the back passages formed on the back side of the core split portion, and is an enlarged view of part B in FIG. 2 ; It is a top view of a molded object. FIG. 9 is a cross-sectional view of the molded body taken along line IX-IX of FIG. 8; It is a back view of a molded object. It is a side view of a molded object. FIG. 4 is a cross-sectional view of the injection molding apparatus showing a state during injection of molten resin. FIG. 4 is a cross-sectional view of the core side in a mold open state after injection molding; FIG. 4 is a cross-sectional view of an inter-rotating portion passage and a resin residue formed therein (an inter-rotating portion residue) in a mold opened state after injection molding; FIG. 14 is a cross-sectional view showing a state in which the molded body is pushed out from the core body, following the state in FIG. 13; FIG. 15 is a cross-sectional view showing a state in which the intermediate portion of the inter-rotating portion residual body is pushed out from the core body, following the state of FIG. 14 ; FIG. 16 is a cross-sectional view showing a state in which the resin residue is pushed out from the core body, following the state in FIG. 15;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. First, with reference to FIGS. 8 to 11, a molded body molded by the injection molding apparatus of this embodiment will be described. The molded body 30 shown in FIGS. 8 to 11 is made of resin such as PC (polycarbonate), PP (polypropylene), PE (polyethylene), and ABS resin. The molded body 30 is, for example, a part assembled to a vehicle (for example, a part provided in the back door of the vehicle). The molded body 30 has a plate-like main body portion 301 and a bent portion 302 extending from the outer peripheral edge of the main body portion 301 toward the back side of the main body portion 301 in a bent manner. The main body portion 301 has a shape elongated in the left-right direction of the paper surface of FIG. 8 when viewed from above in FIG. 8 .

The bent portion 302 is formed continuously over the entire circumference of the outer peripheral edge of the body portion 301 . As shown in FIG. 10, an end surface 303 of the bent portion 302 is formed with a plurality of (three in this embodiment) gate traces 304 indicating gate positions in the injection mold. Further, on the end face 303, traces 305 indicating boundary lines of a plurality of core divisions 5, which will be described later, are formed. The marks 305 are formed by the number of core split portions 5 . In this embodiment, since four core split portions 5 are provided, four marks 305 are also formed. Each trace 305 is formed so as to connect the outer peripheral line and the inner peripheral line of the end surface 303 .

Further, as shown in FIG. 11, on the outer side surface of the bent portion 302, a mark 306 is formed to indicate the position of a mating surface (in other words, a parting line) between the cavity 2 and the core split portion 5, which will be described later. The marks 306 are linearly formed along the circumferential direction of the outer side surface and formed continuously over the entire circumference in the circumferential direction. Further, marks 307 are formed on the outer side surface of the bent portion 302 to indicate the boundary lines of the plurality of core split portions 5 (see FIG. 11). The marks 307 are formed by the number of the core split portions 5, that is, four. The trace 307 is formed so as to connect the trace 306 extending in the circumferential direction and the outer peripheral line of the end surface 303 .

Next, the configuration of an injection molding apparatus for injection molding the molded body 30 will be described. The injection molding apparatus 1 shown in FIGS. 1 and 2 includes a mold, which has a cavity 2 as a fixed mold and a core 3 as a movable mold. The cavity 2 is a template whose position does not change during the mold opening operation or mold closing operation of the injection molding apparatus 1 . The cavity 2 is a mold plate on the side from which the molded body 30 moves away as the injection molding apparatus 1 (core 3) opens the mold after molding. The cavity 2 forms a molding space 6 for injection-molding a molding 30 with the core 3 in the mold closed state. The molding space 6 is formed in a shape corresponding to the shape of the molded body 30 . Specifically, the molding space 6 has a body portion space 61 corresponding to the body portion 301 of the molded body 30 and a bending portion space 62 corresponding to the bending portion 302 (see FIGS. 2 and 3). In the present embodiment, the main body space 61 is formed to extend in a direction slightly inclined with respect to the direction perpendicular to the opening and closing direction of the mold (cavity 2, core 3). It may be formed as The bent space 62 is formed so as to bend from the outer peripheral edge of the main body space 61 toward the core 3 side. The end surface 53a (see FIG. 3) of the bending space 62 corresponds to the end surface 303 of the bending portion 302 of the molded body 30, and the core 3 in a direction substantially parallel to the opening/closing direction of the mold (cavity 2, core 3). side toward the cavity 2 side.

A concave shape 21 corresponding to the surface (design surface) of the molded body 30 is formed on the surface of the cavity 2 facing the core 3 . The concave shape 21 forms part of the inner wall surface of the molding space 6 . Specifically, as shown in FIG. 3, the concave shape 21 includes a portion 21a corresponding to the surface of the body portion 301 of the molded body 30 and a portion corresponding to a portion of the outer side surface of the bent portion 302 of the molded body 30. 21b.

Also, as shown in FIG. 1, two molding spaces 6 are formed in one injection molding apparatus 1 . In other words, the injection molding apparatus 1 is configured to be able to injection-mold two moldings 30 at the same time. The two molding spaces 6a and 6b are arranged in a horizontal direction perpendicular to the opening/closing direction of the cavity 2 and the core 3. As shown in FIG. Also, the two molding spaces 6a and 6b are formed in a 180° rotationally symmetrical shape with respect to a point O on the horizontal plane in FIG. That is, when one molding space 6a is rotated 180° around an axis passing through the point O and perpendicular to the plane of FIG. coincides with space 6b. A point O is a point on an imaginary straight line L1 extending in the lateral direction of the molding space 6 and passing through the middle of the molding space 6 in the longitudinal direction when viewed from above in FIG. A portion of the cavity 2 forming one molding space 6a side and a portion forming the other molding space 6b side are integrated.

The core 3 is provided so as to be openable and closable with respect to the cavity 2 . That is, the core 3 is clamped to the cavity 2 in a mold closed state (Fig. 2 state) and a mold open state separated from the surface 22 of the cavity 2 . The direction of the mold closing operation or the mold opening operation of the core 3 is the direction perpendicular to the parting line (vertical direction on the paper surface of FIG. 2). The core 3 is a mold plate on the side to which the molded body 30 adheres as the injection molding apparatus 1 (core 3) opens the mold after molding. The core 3 forms the molding space 6 with the cavity 2 when the mold is closed. A convex shape 31 corresponding to the back surface of the molded body 30 is formed on the surface of the core 3 facing the cavity 2 . The convex shape 31 forms part of the inner wall surface of the molding space 6 . Specifically, as shown in FIG. 3, the convex shape 31 includes a portion 42a corresponding to the back surface of the main body portion 301 of the molded body 30, a portion 42b corresponding to the inner side surface of the bent portion 302 of the molded body 30, and a bent portion. It includes a portion 53 a corresponding to the end surface 303 of the portion 302 and a portion 53 b corresponding to a portion of the outer side surface of the bent portion 302 .

The core 3 has a core body 4 and a core split portion 5 . The core body 4 forms most of the convex shape 31. Specifically, as shown in FIG. A portion 42b corresponding to the side surface is formed. Further, as shown in FIG. 2 , a concave portion 43 for arranging the core split portion 5 is formed on the surface 41 of the core body 4 facing the cavity 2 . The concave portion 43 is formed so as to surround the entire outer circumference of the molding space 6 . In addition, the outer circumference of the molding space 6 refers to the outer circumference of the molding space 6 when viewed from the plan view of FIG. 1 (the opening and closing direction of the cavity 2 and the core 3).

Although two molding spaces 6 are provided, the core body 4 is not divided for each molding space 6 . That is, the portion forming one molding space 6a side and the portion forming the other molding space 6b side of the core body 4 are integrated.

The core split portion 5 is provided in the concave portion 43 in the mold closed state, in other words, is provided so as to surround the entire outer circumference of the molding space 6 as shown in FIG. Further, the core split portion 5 forms a portion 53 (see FIG. 3) of the inner wall surface of the molding space 6 in the mold closed state. Specifically, as shown in FIG. 3, the inner wall surface 53 formed by the core split portion 5 is a part of the surface forming the bending portion space 62 in the molding space 6. More specifically, It includes a portion 53 a corresponding to the end surface 303 of the bent portion 302 of the molded body 30 and a portion 53 b corresponding to a portion of the outer side surface of the bent portion 303 . In the present embodiment, the entire range of the width d9 (see FIG. 3) of the portion 53a corresponding to the end surface 303 of the bent portion 302 is formed by the core split portion 5. It may be composed of the portion 5 and the remaining portion may be composed of the core body 4 .

As shown in FIG. 2, the core split portion 5 has a shape having a surface 51 facing the cavity 2, a back surface 52 on the opposite side, and a side surface formed to connect the front surface 51 and the back surface 52. formed in The front surface 51 and the back surface 52 are provided parallel to each other. Also, the front surface 51 and the back surface 52 are provided parallel to the parting line (PL) between the cavity 2 and the core body 4 .

The surface 51 of the core split portion 5 functions as a mating surface that is mated with the surface 22 of the cavity 2 when the mold is closed. The mating surface 51 is formed along the entire circumference of the molding space 6 . A mating surface 41 (see FIG. 2) of the core body 4 that is mated with the surface 22 of the cavity 2 is formed outside the mating surface 51 of the core split portion 5 (away from the molding space 6). The mating surface 41 of the core body 4 and the mating surface 51 of the core split portion 5 form a surface 32 that defines the parting line of the core 3 .

The core division part 5 is divided into a plurality of parts along the outer periphery of the molding space 6, and specifically divided into four parts. As shown in FIG. 1, the four core divisions 5 define a first longitudinal outer peripheral line 63 extending in the longitudinal direction of the molding space 6 among the outer peripheral lines of the molding space 6 (first longitudinal outer peripheral line 63). A first core split 5a (provided adjacent to line 63) defines a second longitudinal perimeter line 64 extending longitudinally of molding space 6 (adjacent to second longitudinal perimeter line 64). defines a second core split portion 5b (provided adjacent to the first transverse direction outer circumference line 65) and a first transverse direction outer circumference line 65 extending in the transverse direction of the molding space 6 (provided adjacent to the first transverse direction outer circumference line 65). ) defines a third core split portion 5c and a second transverse direction outer peripheral line 66 extending in the transverse direction of the molding space 6 (provided adjacent to the second transverse direction outer peripheral line 66). and a fourth core split portion 5d. The first and second core divisions 5a and 5b face each other with the molding space 6 interposed therebetween. The third and fourth core divisions 5c and 5d face each other with the molding space 6 interposed therebetween.

Each of the core split portions 5a to 5d is provided in such a manner as to be fitted to the adjacent core split portions 5a to 5d. The fitting portion is provided at a boundary portion 54 (see FIG. 1) between two adjacent core split portions. As will be described later, passages for introducing molten resin into the molding space 6 are formed on the back sides of the first and second core divisions 5a and 5b, while the third and fourth core divisions 5c, The passage is not formed on the back side of 5d. Here, the first and second core split portions 5a and 5b having the passage formed on the back side are referred to as passage-existing split portions 5X, and the third and fourth core split portions 5c and the passage not formed on the back side. 5d is called an undivided passage portion 5Y. FIG. 4 exemplifies the fitting state of the divided passage portion 5X and the non-divided passage portion 5Y. A boundary portion 54 between the divided passage portion 5X and the non-divided passage portion 5Y is composed of a side surface 55 of the divided passage portion 5X and a side surface 56 of the undivided passage portion 5Y that contacts the side surface 55 of the divided passage portion 5X. A convex portion 57 is provided on the side surface 55 of the divided passage portion 5X, and a concave portion 58 is provided on the side surface 56 of the non-divided passage portion 5Y. These projections 57 and recesses 58 are fitted.

More specifically, the convex portion 57 is formed so as to be continuous with, for example, the rear surface 52 (the surface opposite to the surface 51 facing the cavity 2 ) of the divided passage portion 5X, but is not connected to the surface 51 of the side surface 55 . It may be formed at an intermediate position on the back surface 52 . The recessed portion 58 is formed, for example, by notching the back surface 52 of the undivided passage portion 5Y, but it may be formed at an intermediate position between the front surface 51 and the back surface 52 on the side surface 56 . At least a surface 57a of the protrusion 57 facing the front surface 51 and a surface 58a of the recess 58 facing the rear surface 52 are in contact with each other. Due to the fitting of these protrusions 57 and recesses 58, the force acting in the direction of approaching the cavity 2 is transmitted from the divided passage portion 5X to the non-divided passage portion 5Y. In addition, the convex portion 57 and the concave portion 58 correspond to the force transmission portion of the present disclosure.

A convex portion 57 and a concave portion 58 as a force transmission portion are formed in each of the plurality of boundary portions 54 shown in FIG. That is, the convex portion 57 and the concave portion 58 correspond to the boundary portion 54 between the first core divided portion 5a and the third core divided portion 5c, and the boundary portion between the second core divided portion 5b and the third core divided portion 5c. 54, a boundary portion 54 between the second core division portion 5b and the fourth core division portion 5d, and a boundary portion 54 between the first core division portion 5a and the fourth core division portion 5d. .

As shown in FIG. 1, the core dividing portion 5 is provided for every two molding spaces 6a and 6b. That is, the core split portion 5 includes a core split portion 5A provided so as to surround one molding space 6a and a core split portion 5B provided so as to surround the other molding space 6b. One core split portion 5A and the other core split portion 5B are provided separately from each other. The core split portions 5A and 5B are split into the first to fourth core split portions 5a to 5d, respectively. The core split portions 5A and 5B are formed in a 180° rotationally symmetrical shape with respect to a point O on the horizontal plane in FIG. That is, when one core split portion 5A is rotated by 180° around an axis passing through point O and perpendicular to the paper surface of FIG. 1, it coincides with the other core split portion 5B.

The injection molding apparatus 1 includes a resin injection section (not shown) for injecting molten resin. The resin injection part is provided on the cavity 2 side. As shown in FIGS. 1 and 2, the cavity 2 and the core 3 (core body 4, core split portion 5) are provided with passages 7 (sprues) for guiding the molten resin injected from the resin injection portion to the molding space 6. , runners and gates) are formed. As shown in FIG. 2, the passage 7 includes a cavity-side passage 71 formed inside the cavity 2 so as to face the core body 4 side, a rotation axis Z (see FIG. 2) described later, and the cavity 2 and the core body. 4 and a front side passage 73 extending from the rotation center 72 in the in-plane direction of the mating surfaces 22 and 41 . Furthermore, the passages 7 include a side upstream side passage 74 formed so as to extend from the end of the front side passage 73 toward the back surface 52 of the core split portion 5 along the side surface of the core split portion 5, and a side upstream side passage 74. and a back side passage 75 formed along the back surface 52 of the core split portion 5 from the end of the back side passage 75 and extending from the end of the back side passage 75 toward the surface 51 of the core split portion 5 along the side surface of the core split portion 5 . and a lateral downstream passage 76 formed in the .

The cavity-side passage 71 functions as a sprue. The front side passage 73, the side upstream side passage 74, the back side passage 75, and the side side downstream side passage 76 function as runners. An end portion 77 of the side downstream passage 76 functions as a gate.

Each part 71-76 of the passage 7 is formed for each two molding spaces 6a, 6b, but each part 71-76 of the passage 7 for one molding space 6a and each part of the passage 7 for the other molding space 6b. 71 to 76 are formed in positions, shapes (width, length) and numbers that are 180° rotationally symmetrical with respect to point O on the horizontal plane in FIG.

As shown in FIG. 1 , a plurality (specifically, four) of rotation centers 72 are provided for each molding space 6 . Each rotation center portion 72 is provided outside the molding space 6 and outside the core split portion 5 on a horizontal plane perpendicular to the mold opening/closing direction when viewed in plan view in FIG. Each rotation center portion 72 is located within the width of the molding space 6 in the longitudinal direction.

First and second rotation center portions 72a and 72b of the plurality of rotation center portions 72 are provided at positions between the first molding space 6a and the second molding space 6b. Further, the first and second rotation center portions 72a and 72b are defined by a line segment 64 (second 2 are spaced apart along the direction in which the longitudinal perimeter 64) of the mold 2 extends (that is, the longitudinal direction of the molding space 6). The distances of the first and second rotation centers 72a and 72b from the first molding space 6a are the same as the distances from the second molding space 6b. The distance between the first rotation center portion 72a and the point O (see FIG. 1) and the distance between the second rotation center portion 72b and the point O are the same. From the first and second rotation center portions 72a and 72b, it branches into a passage toward the first molding space 6a and a passage toward the second molding space 6b.

Among the plurality of rotation center portions 72, the third and fourth rotation center portions 72c and 72d are positioned at the first and second rotation center portions 72a and 72b with the molding space 6 and the core split portion 5 interposed therebetween. It is located on the opposite side of the road. The third and fourth rotation centers 72c and 72d are line segments 63 (first They are spaced along the direction in which the longitudinal perimeter lines 63) extend (that is, the longitudinal direction of the molding space 6).

The cavity-side passage 71 (see FIG. 2) is provided so as to communicate with the rotation center portion 72 or the front-side passage 73 in the mold closed state. Specifically, in this embodiment, the cavity-side passage 71 is provided so as to communicate with the first to third rotation center portions 72a to 72c. In other words, the openings of the cavity-side passages 71 are located at positions facing the first to third rotation centers 72a to 72c. On the other hand, the cavity side passage 71 is not directly connected to the fourth rotation center portion 72d. not formed.

As shown in FIG. 1, the front side passage 73 includes a first front side passage 731 formed from the rotation center portion 72 toward the core split portion 5 and one of the plurality of rotation center portions 72a to 72d. It has a second front side passage 732 that connects with the other one. In addition, below, the 2nd front side channel|path 732 may be called the channel|path between rotary parts. One or both of the mating surface 22 of the cavity 2 and the mating surface 41 of the core body 4 are formed with grooves forming the first front side passages 731 .

Specifically, the second front-side passage 732 (passage between rotating portions) connects the third rotation center portion 72c and the fourth rotation center portion 72d. As shown in FIG. 5, the second front side passage 732 includes a first portion 732a connected at one end to one rotation center portion 72c and a second portion 732b having one end connected to the other rotation center portion 72d. , and a third portion 732c connected between the first portion 732a and the second portion 732b. At the boundary between the first portion 732a and the third portion 732c, there is a shape changing portion 732d that changes the shape from the first portion 732a to the third portion 732c. It becomes a connecting portion with the portion 732c. In addition, at the boundary between the second portion 732b and the third portion 732c, there is a shape changing portion 732e that changes the shape from the second portion 732b to the third portion 732c. It becomes a connecting portion with the third portion 732c. Thus, the second front side passage 732 has shape changing portions 732d and 732e along the way.

The shape and width of the shape changing portions (connecting portions) 732d and 732e (the width of the overlapping portion of the first portion 732a and the third portion 732c, the width of the overlapping portion of the first portion 732a and the third portion 732c) When the intermediate portion 513 (the portion corresponding to the third portion 732c of the second front passage 732) of the resin residue 510 (see FIG. 14) corresponding to the front passage 732 is pushed by the pushing member 17 (see FIG. 14) , and portions 514 and 515 (see FIG. 14) corresponding to the shape-changing portions 732d and 732e.

As shown in FIG. 5, the side surface 732f of the third portion 732c has a draft angle. Specifically, the width between the side surfaces 732f gradually decreases as the third portion 732c approaches from the lower surface 732g facing the cavity 2 to the upper surface 732h facing the core body 4. A slope is set on the side surface 732f. In other words, the third portion 732c is formed in a substantially trapezoidal shape in which the width of the lower surface 732g is larger than the width of the upper surface 732h when viewed in cross section in FIG.

As shown in FIG. 1, the back side passages 75 are formed on the back sides of the first and second core segments 5a and 5b, and on the back sides of the third and fourth core segments 5c and 5d. It has not been. In addition, the back side passage 75 has a gate conducting passage 751 whose downstream end is connected to a gate 77 (see FIGS. 1 and 2), which is an introduction port of the molding space 6, via a side downstream passage 76 (see FIG. 2). and a closed passage 752 closed at its downstream end. It should be noted that the gate conduction passage 751 is a passage in which the molten resin cannot be introduced into the molding space 6 if the passage 751 does not exist among the back passages 75 . The closed passage 752 is a passage other than the gate conducting passage 751 in the back side passage 75. In other words, even if the passage 752 does not exist, the closed passage 752 is a passage through which the molten resin can be introduced into the molding space 6. say.

The gate conducting path 751 is formed in the mating surface between the core body 4 and the core split portion 5, as shown in FIG. Although FIG. 6 shows an example in which the groove of the gate conducting portion 751 is formed on the surface of the core body 4 , the groove may be formed on the surface of the core dividing portion 5 . The gate conduction passage 751 has a draft angle on the side surface 7512 as viewed in cross section in FIG. Specifically, the width between the side surfaces 7512 of the gate conducting passage 751 is gradually reduced as it approaches from the upper surface 7510 facing the core body 4 to the lower surface 7511 facing the core split portion 5 . , the side 7512 is sloped. In other words, the gate conducting path 751 is formed in a substantially trapezoidal shape with the upper surface 7510 wider than the lower surface 7511 when viewed in cross section in FIG.

The maximum width d4 (see FIG. 6) of the gate conducting passage 751 in the direction perpendicular to both the opening/closing direction of the core 3 and the cavity 2 and the direction in which the passage 751 extends is It is the same as the maximum width d8 (see FIG. 7) in the direction perpendicular to both directions in which 752 extends. However, the width d4 of the gate conducting passage 751 may be larger than the width d8 of the closed passage 752.

Further, the gate conduction passage 751 protrudes laterally (in a direction parallel to the mating surface) at the end in the width direction (horizontal direction in FIG. 6) at the position of the mating surface between the core body 4 and the core split portion 5. It has a narrow portion 7513 . The small width portions 7513 are formed at both ends of the gate conduction path 751 in the width direction. The small width portion 7513 is a portion for suppressing opening of the mating surface between the core body 4 and the core split portion 5 during injection molding by rapidly solidifying the molten resin flowing through the small width portion 7513 . The width d2 of the narrow portion 7513 in the direction perpendicular to the mating surface is smaller than the maximum width d1 of the gate conduction passage 751 in the direction perpendicular to the mating surface. Under the condition that the width d2 is smaller than the maximum width d1, the molten resin flowing through the small width portion 7513 is set appropriately so that the mating surfaces of the core body 4 and the core split portion 5 do not open. . Similarly to the width d2, the width d3 of the small width portion 7513 in the direction parallel to the mating surface is also such that the molten resin flowing through the small width portion 7513 solidifies quickly, and the mating surface between the core body 4 and the core split portion 5 is It is set appropriately so that it does not open.

In this embodiment, three gate conducting passages 751 are formed per molding space 6 . That is, in this embodiment, three gates 77 (see FIGS. 1 and 2) are formed in one molding space 6 . Each gate conduction passage 751 is provided downstream of the first to third rotation center portions 72a to 72c. On the other hand, no gate conducting passage 751 is provided downstream of the fourth rotating flow core 72d. Each gate conduction passage 751 is formed to extend in a direction that intersects the longitudinal direction of the molding space 6 (longitudinal outer peripheral lines 63 and 64) when viewed from above in FIG.

The closed passage 752 is formed in the mating surface between the core body 4 and the core split portion 5, as shown in FIG. Although FIG. 7 shows an example in which the groove of the closed passage 752 is formed on the surface of the core body 4 , the groove may be formed on the surface of the core split portion 5 . Similar to the gate conducting passage 751, the closed passage 752 has a side surface 7522 with a draft when viewed in cross section in FIG. there is

Also, the width of the closed passage 752 (the width in the direction perpendicular to the extending direction of the closed passage 752) is smaller than the width of the gate conducting passage 751 (the width in the direction perpendicular to the extending direction of the gate conducting passage 751). More specifically, the width d5 (see FIG. 7) of the closed passage 752 in the direction perpendicular to the mating surface of the core body 4 and the core split portion 5 is equal to the width d1 ( 6). Widths d1 and d5 are widths in the vertical direction of the paper surface of FIGS. Note that the width d5 may be the same as the width d1.

The width d8 (see FIG. 7) of the closed passage 752 in the direction perpendicular to both the opening/closing direction of the core 3 and the cavity 2 and the direction in which the passage 752 extends is is the same as the width d4 (see FIG. 6) in the direction perpendicular to both of the extending directions. However, it is not limited to this, and the width d8 of the closed passage 752 may be smaller than the width d4 of the gate conduction passage 751, or may be larger.

Furthermore, the closed passage 752 has a small width projecting laterally (in a direction parallel to the mating surface) at the end in the width direction (horizontal direction in FIG. 7) at the position of the mating surface between the core body 4 and the core split portion 5 . It has a part 7523 . The small width portions 7523 are formed at both ends of the closed passage 752 in the width direction. The closed passage 752 is a portion for suppressing opening of the mating surfaces of the core body 4 and the core split portion 5 during injection molding by rapidly solidifying the molten resin flowing through the narrow portion 7523 . A width d6 of the narrow portion 7523 in the direction perpendicular to the mating surface is smaller than the maximum width d5 of the closed passage 752 in the perpendicular direction. Under the condition that the width d6 is smaller than the maximum width d5, the molten resin flowing through the small width portion 7523 is set appropriately so that the mating surfaces of the core body 4 and the core split portion 5 do not open. . Similarly to the width d6, the width d7 of the small width portion 7523 in the direction parallel to the mating surface is also such that the molten resin flowing through the small width portion 7523 solidifies quickly, and the mating surface between the core body 4 and the core split portion 5 is It is set appropriately so that it does not open. Widths d6 and d7 of the narrow portion 7523 may be the same as or different from the widths d2 and d3 of the narrow portion 7513 (see FIG. 6) of the gate conduction path 51 .

The closed passages 752 are, as shown in FIG. ), and a second closed passage 752b leading to . The second closed passage 752b is provided downstream of the fourth rotating flow core 72d.

1, the back side passage 75 has a radial passage extending in the radial direction of a circle centered on the rotation center portion 72. As shown in FIG. The gate conducting passage 751 is set as a radial passage. Hereinafter, the gate conducting passage 751 may be referred to as a radial passage. Further, the back side passage 75 has a circumferential passage extending in a direction along the outer periphery of the molding space 6 when viewed in plan view in FIG. 1 . The first closed passage 752a is set as a circumferential passage. A part of the second closed passage 752b is set as a circumferential passage. Below, the closed passage 752 may be referred to as a circumferential passage. The circumferential passage 752 extends along the longitudinal direction of the molding space 6 .

The closed passage 752 has a plurality of circumferential passages 752c, 752d branching from one radial passage 751 in different directions. In this embodiment, a gate conduction passage 751 provided downstream of the third rotation center portion 72c is set as the radial passage 751 from which the plurality of circumferential passages 752c and 752d branch.

When the region on the horizontal plane perpendicular to the opening/closing direction of the molds 2 and 3 is divided into a first region and a second region with the radial passage 751 as a boundary, one circumferential passage 752c extends from the radial passage 751 to the second region. 1 area (left side of the radial passage 751 in FIG. 1). The other circumferential passage 752d branches from the radial passage 751 to the second region side (the right side of the radial passage 751 in FIG. 1).

As will be described later, the rotation shafts 10 (see FIGS. 2 and 5) are connected to the first to fourth rotation centers 72a to 72d, respectively. The rotating shaft 10 connected to the third rotation center portion 72c located upstream of the circumferential passages 752c and 752d rotates clockwise in the plane of FIG. 1 when ascending. A circumferential passage 752c provided on the front side in the rotational direction (front side of the radial passage 751) is longer than a circumferential passage 752d provided on the rear side in the rotational direction.

Circumferential passages 752 other than the circumferential passages 752c and 752d (circumferential passages connected to the first, second, and fourth rotation centers 72a, 72b, and 72d) are provided on the front side of the rotating shaft 10 in the rotation direction. be done.

Among the inner wall surfaces of the backside passage 75, the area S1 of the inner wall surface 59 (see FIGS. 2, 6, and 7) forming part of the back surface 52 of the core split portion 5 is equal to the area S1 of the bending portion space 62 of the molding space 6. It is set to be larger than the area S2 of the end surface 53a (see FIG. 3). Preferably, area S1 is larger than area S2. The area S1 is the sum of the areas of the inner wall surfaces 59 of the four core divisions 5a to 5d. The inner wall surface 59 is the upper surfaces 7510 and 7520 (see FIGS. 6 and 7) of the gate conducting passage 751 or the closed passage 752 . The area S2 is the sum of the areas of the end faces 53a of the four core divisions 5a to 5d.

For example, if the width d9 (see FIG. 3) of the end surface 53a is 2.5 mm and the length of the end surface 53a in the circumferential direction of the molding space 6 is 1340 mm, the area S2 of the end surface 53a is 2.5 mm×1340 mm=3350 mm ² . . The area S2 of the inner wall surface 59 is determined by the widths d4 and d8 (see FIGS. 6 and 7) of the back passage 75 (inner wall surface 59) and the length of the back passage 75. As shown in FIG. Therefore, the widths d4 and d8 and the length of the back side passage 75 are set so that the area S2 is 3350 mm ² or more. For example, if the widths d4 and d8 of the back side passage 75 are 9 mm, the length of the back side passage 75 is set to 3350 mm ² ÷9=372.22 mm or more. In this embodiment, the area of the inner wall surface 59 of the closed passage 752 (circumferential passage) is set to be equal to or larger than the area S1 of the end surface 53a. That is, the width d8 and the length of the closed passage 752 are set so that the area of the closed passage 752 is S1 or more.

The end surface 53 a functions as a first working surface on which force acts in the direction away from the cavity 2 by the molten resin introduced into the molding space 6 . In addition, the inner wall surface 59 functions as a second action surface on which force acts in the direction of approaching the cavity 2 by the molten resin flowing through the back passage 75 .

The side downstream passage 76 (see FIG. 2) is connected to the gate conduction passage 751 of the back passage 75 . The end 77 of the side downstream side passage 76 on the opposite side to which the gate conduction passage 751 is connected is set as a gate serving as an introduction port to the molding space 6 .

In addition to the molds 2 and 3 described above, the injection molding apparatus 1 includes molded body extrusion rods 8 and 9 for extruding the molded body 30 stuck to the core 3 from the core 3 when the mold is opened after injection molding. (See Figure 2). The core body 4 is formed with through-holes through which the rod-shaped portions 8 and 9 are inserted. The bar-shaped portions 8 and 9 are provided movably between a state of being retracted into the core body 4 (see FIG. 2) and a state of being projected from the core body 4 (see FIG. 15). The through holes function as guide surfaces that guide the vertical movement of the bar-shaped portions 8 and 9 . One end sides of the bar-shaped portions 8 and 9 protrude from the through hole of the core body 4 to the back side of the core body 4 .

The rod-shaped portions 8 and 9 are provided on the core 3 side. 2 rods 9; The first rod-shaped portion 8 is formed in a rod-like shape extending parallel to the opening/closing direction of the molds 2 and 3 . One end side of the first rod-shaped portion 8 is fixed to the back surface 52 of the core split portion 5 by a fastening member such as a bolt or nut, and the other end side is in contact with the ejection plate 19 which will be described later. The first bar-shaped portion 8 is provided for each of the core split portions 5a to 5d (see FIG. 1). Specifically, in the first and second core split portions 5a and 5b extending in the longitudinal direction of the molding space 6, two locations per one core split portion 5a and 5b (core split portions 5a and 5b ) are provided with first rod-shaped portions 8 on both ends thereof in the longitudinal direction thereof. On the other hand, in the third and fourth core split portions 5c and 5d extending in the lateral direction of the molding space 6, one first bar-shaped portion 8 is provided for each core split portion 5c and 5d. It is

The second rod-shaped portion 9 is shaped like a rod extending parallel to the opening/closing direction of the molds 2 and 3 . One end of the second rod-shaped portion 9 constitutes part of the surface 31 of the molding space 6 on the core 3 side in the closed state shown in FIG. The other end side of the second rod-shaped portion 9 is in contact with the push plate 19 .

The injection molding apparatus 1 also has a rotary shaft 10 on the core 3 side (see FIGS. 2 and 5). The rotating shaft 10 is shaped like a rod having an axis Z extending parallel to the opening and closing direction of the molds 2 and 3 . The rotating shaft 10 is provided at a position where its axis Z intersects the rotation center portion 72 of the passage 7 . A rotating shaft 10 is provided for each of the rotation centers 72a to 72d. The core body 4 is formed with a through hole through which the rotary shaft 10 is inserted. The rotating shaft 10 is provided movably between a state of being retracted into the core body 4 (see FIG. 2) and a state of protruding from the core body 4 (see FIG. 17). The through hole functions as a guide surface that guides the vertical movement of the rotating shaft 10 . One end of the rotating shaft 10 protrudes from the through hole of the core body 4 to the back side of the core body 4 .

The tip of the rotary shaft 10 forms part of the inner wall surface of the rotary center portion 72 in the closed state shown in FIGS. 2 and 5 . Further, a protruding portion 11 protruding in the direction of the axis Z is provided at the tip of the rotating shaft 10 . The projecting portion 11 is formed in a tapered prismatic shape (for example, a rectangular prism shape). The projecting portion 11 is positioned in the space within the rotation center portion 72 in the mold closed state shown in FIGS. 2 and 5 . The other end of the rotating shaft 10 faces the upper surface of the ejector plate 19 with an interval e in the closed state shown in FIG. The other end side of the rotary shaft 10 is fixed to a connecting member 18 which will be described later.

Furthermore, a guide groove 12 is formed along the direction of the axis Z on the side surface of the rotating shaft 10 . The guide groove 12 has a first linear portion 12a formed linearly parallel to the axis Z and a direction formed continuously from the lower end of the first linear portion 12a from the upper side (the side on which the projecting portion 11 is provided). It has a changing portion 12b and a second linear portion 12c that is continuous with the lower end of the direction changing portion 12b and that is linearly formed in parallel with the axis Z. As shown in FIG. The direction changing portion 12b rotates the rotating shaft 10 by a predetermined angle (for example, 90°) around the axis Z as the guide convex portion 13 described later shifts from the first linear portion 12a to the direction changing portion 12b. It is formed. That is, the guide groove 12 is formed so that the position changes by a predetermined angle in the direction of rotation about the axis Z at an intermediate position (position of the direction changing portion 12b).

As will be described later, the rotary shaft 10 rotates in the direction around the axis Z as the rotary shaft 10 rises along the guide groove 12. The direction of rotation during the rise is the circumferential passage 752 (closed passage). is positioned on the front side in the direction of rotation. Specifically, the rotation direction of the rotation shaft 10 provided at the position of the first rotation center portion 72a is determined in the clockwise direction on the paper surface of FIG. The rotation direction of the rotation shaft 10 provided at the position of the second rotation center portion 72b is defined as the clockwise direction on the paper surface of FIG. The rotation direction of the rotation shaft 10 provided at the position of the third rotation center portion 72c is such that the longer one of the plurality of circumferential passages 752c and 752d branched from one radial passage 751 in opposite directions. It is defined so as to be located on the front side in the direction of rotation, and more specifically, is defined in the clockwise direction on the paper surface of FIG. The rotation direction of the rotation shaft 10 provided at the position of the fourth rotation center portion 72d is defined as the counterclockwise direction on the paper surface of FIG. The direction changing portion 12b of the guide groove 12 formed on each rotating shaft 10 is formed to rotate the rotating shaft 10 in a predetermined direction, which is clockwise or counterclockwise on the paper surface of FIG. be done.

The injection molding apparatus 1 has a guide protrusion 13 on the core 3 side. The guide protrusion 13 is fixed to the back side of the core body 4 . The guide protrusion 13 is fitted in the guide groove 12, and more specifically, in the mold closed state, is fitted in the first linear portion 12a.

Further, the injection molding apparatus 1 includes a first residue extruding rod-shaped portion 14 having an undercut-shaped tip portion 15 on the core 3 side. The rod-shaped portion 14 is provided so that its axis is parallel to the opening/closing direction of the molds 2 and 3 . The core body 4 is formed with a through hole through which the rod-shaped portion 14 is inserted. The bar-shaped portion 14 is provided movably between a state of being retracted into the core body 4 (see FIG. 2) and a state of being projected from the core body 4 (see FIG. 17). The through hole functions as a guide surface that guides the vertical movement of the bar-shaped portion 14 . One end side of the bar-like bar 14 protrudes from the through hole of the core body 4 to the back side of the core body 4 .

The distal end portion 15 of the bar-shaped portion 14 enters the back side passage 75 in the mold closed state shown in FIG. 751). The bar-shaped portion 14 is provided, for example, directly below the gate 77 . Here, the position directly below the gate 77 means that the bar-shaped portion 14 is positioned on an imaginary straight line passing through the gate 77 and extending in the opening/closing direction of the molds 2 and 3 . The bar-shaped portions 14 are provided in the same number as the gates 77, and are provided at three locations in the present embodiment.

The tip portion 15 is formed in a wedge shape as an undercut shape in which the width of the tip portion 15 in the direction perpendicular to the axis of the rod-shaped portion 14 gradually increases as the tip surface of the tip portion 15 approaches. The other end of the bar-shaped portion 14 faces the upper surface of the push-out plate 19 with an interval e in the closed state shown in FIG. The distance e between the bar-shaped portion 14 and the ejector plate 19 is the same as the distance e between the rotating shaft 10 and the ejector plate 19 . Note that the tip portion 15 corresponds to the extrusion blocking portion of the present disclosure.

The injection molding apparatus 1 includes a spring member 16 connected to the other end side of the rod-shaped portion 14, as shown in FIG. The spring member 16 urges the rod-shaped portion 14 to pull in the opposite direction (the direction away from the cavity 2) when the rod-shaped portion 14 receives a force in the direction of approaching the cavity 2. As shown in FIG. The spring member 16 and the rod-shaped portion 14 are connected to a connecting member 18 .

When the rotating shaft 10 and the rod-shaped portion 14 are used as the first residue extruding portion, the injection molding apparatus 1 has a second residue extruding portion on the core 3 side in addition to the first residue extruding portions 10 and 14. It has a functioning second residue pusher bar 17 (see FIG. 5). The rod-shaped portion 17 is provided so that its axis is parallel to the opening/closing direction of the molds 2 and 3 . The rod-shaped portion 17 is a member for pushing out the intermediate portion 732c (see FIG. 5) of the second front side passage 732 (passage between rotating portions) from the core body 4. As shown in FIG. In the mold closed state shown in FIG. 5, the tip of the bar-shaped portion 17 constitutes a part of the inner wall surface of the intermediate portion 732c on the core body 4 side. The core body 4 is formed with a through hole through which the rod-shaped portion 17 is inserted. The rod-like portion 17 is provided movably between a state of being retracted into the core body 4 (see FIG. 5) and a state of being projected from the core body 4 (see FIG. 16). The through hole functions as a guide surface that guides the vertical movement of the bar-shaped portion 17 . Further, one end side of the rod-shaped bar 17 protrudes from the through hole of the core body 4 to the back side of the core body 4 and contacts the push plate 19 (see FIG. 2).

The injection molding apparatus 1 further includes a connecting member 18, an extrusion plate 19, and a drive section 20, as shown in FIG. A connecting member 18 is arranged between the back surface of the core body 4 and the push plate 19 and connected to the rotating shaft 10 , the rod-like portion 14 and the spring member 16 . The ejector plate 19 is a member arranged on the back side of the core body 4 for ejecting the above-described molded body ejector rod-shaped portions 8 and 9 and residual body ejector portions 10, 14 and 17 toward the cavity 2 side. The ejector plate 19 is provided so as to be able to move up and down in a direction parallel to the opening and closing direction of the molds 2 and 3 . The drive unit 20 is a member for raising and lowering the ejector plate 19, and is, for example, an air cylinder, a hydraulic cylinder, or the like.

In addition, the 1st molded object rod-shaped part 8, the extrusion plate 19, and the drive part 20 correspond to the control part of this indication. The gate conducting passage 751 corresponds to the first passage. The closed passage 752 corresponds to the second passage. Further, the first residue push-out rod-shaped portion 14, the rotating shaft 10, the push-out plate 19, and the driving portion 20 correspond to the first residue push-out portion. Further, the rotary shaft 10, the guide groove 12, the guide convex portion 13, the ejector plate 19 and the driving portion 20 correspond to the rotating portion. Further, the second residue push-out rod-shaped portion 17, the push plate 19, and the driving portion 20 correspond to the second residue push-out portion.

Next, operation of the injection molding apparatus 1 will be described. First, the cavity 2 and the core 3 are brought into a mold-closed state (state shown in FIG. 2). Next, molten resin is injected into each of the molding spaces 6a and 6b through the passage 7. As shown in FIG. At this time, the molten resin passes from the upstream side through the cavity side passage 71 of the passage 7, the rotation center portion 72, the front side passage 73, the side upstream side passage 74, the back side passage 7, the side downstream side passage 76, and the gate 77, and is molded. Introduced into space 6 . FIG. 12 shows the state during injection of the molten resin 40 . Next, the molten resin 40 filled in the injection space 6 is cooled to form the molding 30 shown in FIGS. 8 to 11. FIG. In addition, a resin residual body is formed in the passage 7 along with the cooling.

Next, the members 4, 5, 8, 9, 10, 13, 14, 16, 17, 18, and 19 on the core 3 side move away from the cavity 2 to open the mold. 13 and 14 show the mold open state. When the mold is opened, the molded body 30 and the residual resin body 500 are stuck to the core 3 . The molded body 30 and the residual resin body 500 are connected at the position of the gate 77 . 13, the tip portion 15 (undercut-shaped portion) of the first residual body pushing rod-shaped portion 14 bites into the resin residual body 500. As shown in FIG. Further, the tip protrusion 11 of the rotary shaft 10 is intruded into the residual resin body 500 .

A portion 510 (see FIG. 14) formed between the two rotation center portions 72c and 72d of the resin residue 500 is defined as an inter-rotation portion residue, and the inter-rotation portion residue 510 is one of the rotation center portions. It includes a first portion 511 connected to 72c, a second portion 512 connected to the other rotation center portion 72d, and an intermediate portion 513 connecting them. The first and second portions 511 and 512 are formed by grooves on the core body 4 side, and the intermediate portion 513 is formed by grooves on the cavity 2 side.

Next, the drive unit 20 moves the ejection plate 19 in a direction approaching the cavity 2 (upward on the page of FIG. 13). Along with this movement, the molded body extruding rod-shaped portions 8 and 9 (see FIG. 13) and the second residue extruding rod-shaped portion 17 (see FIG. 14) abutting therewith approach the cavity 2 (FIGS. 13 and 14). (upward on the paper) at the same time. As the first molded body extrusion rod-shaped portion 8 rises, the core split portion 5 attached thereto moves in a direction approaching the cavity 2 (upward on the page of FIG. 13), in other words, the core body 4 is extruded. The molded body 30 is pushed out from the core body 4 by raising the second molded body extrusion rod-shaped portion 9 and the core split portion 5 . Further, the intermediate portion 513 (see FIG. 14) of the inter-rotating portion residual body 510 that abuts against the rod-shaped portion 17 is pushed out of the core body 4 by raising the second residual-body pushing rod-shaped portion 17 .

On the other hand, since the rotating shaft 10 and the first residue pushing rod-shaped part 14 are provided with the distance e between the pushing plate 19 and the pushing plate 19 when the pushing plate 19 starts to rise, the rising distance of the pushing plate 19 is It remains stopped until the distance e is reached. Therefore, the resin residue 500 excluding the portion 513 shown in FIG. Until the ascending distance reaches a predetermined distance e, it is prevented from being pushed out from the core body 4 and remains attached to the core body 4.例文帳に追加Thereby, the molded body 30 and the residual resin body 500 are cut (gate cut) at the position of the gate 77 . FIG. 15 shows a state in which the molded body 30 is pushed out from the core body 4 and the residual resin body 500 separated from the molded body 30 sticks to the core body 4 .

Further, the rod-shaped portion 17 abutting on the intermediate portion 513 of the inter-rotating portion residual body 510 shown in FIG. to rise. Further, the rotating shaft 10 connected to the portions 511 and 512 on both sides of the inter-rotating portion residual body 510 remains stopped at the start of extrusion of the compact 30 . Therefore, while force is applied to the intermediate portion 513 in the push-out direction by the rod-shaped portion 17, the portions 511 and 512 on both sides are held by the rotating shaft 10, so that the intermediate portion 513 is as shown in FIG. It is cut from both side portions 511 and 512 and extruded from the core body 4 .

Incidentally, when the portions 511 and 512 on both sides of the inter-rotating portion residual body 510 are detached from the rotating shaft 10 as the rod-shaped portion 17 rises, and are pushed out integrally with the intermediate portion 513, the portions 511 and 512 on both sides, A member (for example, a member having the same shape as the first residue push-out bar 14 ) that prevents the extrusion of 512 may be provided separately from the first residue push-out bar 14 provided near the gate 77 .

The rotating shaft 10 and the first residue push-out rod-shaped part 14 rise by contacting the push-out plate 19 with a delay from the start of extrusion of the molded body 30 . The spring member 16 and the connecting member 18 are also lifted together with the rotating shaft 10 and the first residual body pushing rod portion 14 . As a result, the residual resin body 500 is pushed out from the core body 4 with the undercut shape portion 15 (tip portion) of the bar-shaped portion 14 being fitted (see FIG. 17).

When the guide protrusion 13 is fitted in the first linear portion 12a of the guide groove 12, the rotating shaft 10 rises without rotating. After that, when the guide convex portion 13 enters the direction changing portion 12b of the guide groove 12, the rotating shaft 10 rises while rotating about the axis Z by a predetermined angle. With this rotation, the resin residual body 500 also rotates. With this rotation, the residual resin body 500 is removed from the undercut shaped portion 15 . The undercut shape portion 15 is formed in such a shape that the residual resin body 500 is removed when the rotary shaft 10 rotates.

Further, the position of the direction changing portion 12b is set so that the rotating shaft 10 rotates when the entire resin residual body 500 is pushed out from the parting line (mating surface) of the core body 4 toward the cavity 2 side. there is As a result, contact between the residual resin body 500 and the core body 4 when the residual resin body 500 rotates can be suppressed.

After that, when the guide convex portion 13 enters the second linear portion 12c from the direction changing portion 12b, the rotary shaft 10 is lifted while stopping its rotation.

The molded body 30 and the residual resin body 500 extruded from the core body 4 are collected by a robot arm or the like.

The effects of this embodiment will be described below. In this embodiment, the core split portion 5 is provided so as to surround the entire outer periphery of the molding space 6, and a passage 75 (back passage) for introducing the molten resin into the molding space is provided on the back surface of the core split portion 5. Therefore, the pressure P1 (see FIG. 12) of the molten resin flowing through the back side passage 75 can be applied to the split core portion 5 during injection of the molten resin. This pressure P1 acts on the core split portion 5 in the direction of the cavity 2 side. As a result, it is possible to prevent the mating surfaces of the core split portion 5 and the cavity 2 from opening during injection. Therefore, it is possible to suppress the formation of burrs at positions corresponding to the mating surfaces of the core split portion 5 and the cavity 2 of the molded body 30 . In addition, since the generation of burrs can be suppressed, the pressure of the molten resin can be increased. As a result, surface distortion, sink marks, and the like can be prevented from occurring in the molded body 30, and the appearance quality of the molded body 30 can be improved.

A pressure P<b>2 (see FIG. 12 ) in the direction away from the cavity 2 also acts on the core split portion 5 due to the molten resin introduced into the molding space 6 . This pressure P2 acts on the end surface 53a of the molding space 6 (see FIG. 3). However, since the area S1 on which the pressure P1 in the direction approaching the cavity 2 acts is set to be greater than or equal to the area S2 on which the pressure P2 in the direction away from the cavity 2 acts, the cavity 2 approaches the core split portion 5. The load F1 (=P1×S1) acting in the direction can be made equal to or greater than the load F2 (=P2×S2) acting in the direction away from the cavity 2 . Thereby, it is possible to further suppress opening of the mating surface between the core split portion 5 and the cavity 2 during injection. In addition, generally, the pressure of the molten resin is higher upstream than downstream. That is, since the surface of the back side passage 75 on which the pressure P1 acts is located upstream of the end surface 53a (see FIG. 3) of the molding space 6 on which the pressure P2 acts, it can be expected that the pressure P1 is greater than the pressure P2. . In this case, even if the area S1 on which the pressure P1 acts and the area S2 on which the pressure P2 acts are the same, the load F1 becomes larger than the load F2.

In addition, since it is possible to suppress the opening of the mating surface between the core split portion 5 and the cavity 2 during injection molding, the mold clamping force of the injection molding apparatus 1 can be suppressed, and the mold clamping force is small (in other words, (smaller size) can be employed. Alternatively, an injection molding apparatus 1 having a plurality of molding spaces 6 (two in this embodiment) can be employed.

Further, since the back side passage 75 is formed in the portions 5a and 5b of the divided core portions 5a to 5d and not formed in the remaining portions 5c and 5d, the configuration of the passage 7 including the back side passage 75 can be simplified. .

Further, since the divided passage portion 5X (5a, 5b) having the back passage 75 and the non-divided passage portion 5Y (5c, 5d) not having the back passage 75 are fitted as shown in FIG. The load F1 acting on the divided passage portion 5X can also act on the non-divided passage portion 5Y. As a result, it is possible to prevent the mating surface between the core split portion 5 and the cavity 2 from opening during injection over the entire outer periphery of the molding space 6 . Therefore, it is possible to suppress the generation of burrs on the entire outer periphery of the molded body 30 .

Further, since the back side passage 75 has a closed passage 752 with one end closed in addition to the gate conducting passage 751 communicating with the gate 77, the pressure of the molten resin can be applied to a wide area on the back side of the core split portion 5. . As a result, opening of the mating surfaces of the core split portion 5 and the cavity 2 can be further suppressed.

Moreover, since the closed passage 752 is formed to extend along the circumferential direction of the molding space 6 , the pressure of the molten resin can be applied to the core split portion 5 over a wide range in the circumferential direction of the molding space 6 . As a result, it is possible to prevent the mating surfaces of the core split portion 5 and the cavity 2 from partially opening in the circumferential direction of the molding space 6 .

In addition, since the gate conducting passage 751 and the closing passage 752 are provided at a plurality of locations per passage divided portion 5a, 5b, the pressure of the molten resin can be applied to a wide range of the passage divided portion 5a, 5b. can be done. As a result, opening of the mating surfaces of the core split portion 5 and the cavity 2 can be further suppressed.

In addition, since the closed passage 752 has a plurality of passages 752c and 752d branched in different directions from one gate conducting passage 751 (see FIG. 1), the pressure of the molten resin can be applied to a wide range of the core split portion 5. can. As a result, opening of the mating surfaces of the core split portion 5 and the cavity 2 can be further suppressed.

Also, since the width d5 (see FIG. 7) of the closed passage 752 is smaller than the width d1 (see FIG. 6) of the gate conduction passage 751, the amount of molten resin flowing through the passage 7 can be suppressed. Also, the weight of the resin residue 500 can be suppressed.

In addition, since the passage 7 has an inter-rotating portion passage 732 formed between the two rotation center portions 72c and 72d (see FIGS. 1 and 5), the rear side is passed through the inter-rotating portion passage 732. Passages 75 can be distributed at multiple locations. Thereby, the pressure of the molten resin can be applied to a wide range of the core split portion 5 . In addition, it is possible to prevent the residual resin body 500 rotated by one rotating shaft 10 from becoming too long, and the residual resin body 500 does not come into contact with the members of the injection molding apparatus 1 (such as the molded body extruding rod-shaped portion 9) during rotation. It can be suppressed.

Further, of the residual resin body 500, the intermediate portion 513 of the residual resin body 510 corresponding to the inter-rotating part passage 732 is pushed out from the core body 4 first (see FIG. 16), so the residual resin body 510 is cut before rotation. The two rotating shafts 10 located on both sides of the resin residual body 510 can be rotated.

As shown in FIG. 5, both side portions 732a and 732b of the inter-rotating portion passage 732 are formed on the core body 4 side, while an intermediate portion 732c is formed on the cavity 2 side. Shape-changing portions 732d and 732e are formed at the boundary between 732b and intermediate portion 732c. When the resin residue 513 (see FIG. 14) remaining in the intermediate portion 732c is pushed out by the rod-shaped portion 17, stress can be concentrated on the shape changing portions 732d and 732e. Residue 513 can be cut.

Further, since the intermediate portion 732c of the inter-rotating portion passage 732 is formed with a draft angle, when the core 3 is opened from the cavity 2 after injection molding, the residual resin 513 remaining in the intermediate portion 732c will flow into the cavity 2. It can be suppressed to remain stuck.

In addition, since the residual resin body 500 is rotated by the rotating shaft 10 after being pushed out from the core body 4, the undercut shaped portion 15 that has bitten into the residual resin body 500 can be removed, and the residual resin body 500 can be recovered thereafter. becomes easier. Further, by rotating the residual resin body 500, the residual resin body 500 can be positioned outside the core split portion 5 in the horizontal direction, and the subsequent recovery of the residual resin body 500 is facilitated.

In addition, the rotational direction of each rotating shaft 10 is set so that the portion of the residual resin body 500 corresponding to the circumferential passage (closed passage) 752 is on the front side in the rotating direction. , the portion corresponding to the circumferential passage 752 of the resin residue 500 can be quickly retracted to the outside of the core split portion 5, and the portion can be attached to a member such as the molded body extruding rod-shaped portion 9 (see FIG. 2). You can prevent contact.

Moreover, since the residual resin bodies 500 corresponding to the closed passages 752c and 752d extending in opposite directions are rotated by one rotating shaft 10, the number of rotating shafts 10 can be reduced. Further, the rotation direction of the rotating shaft 10 for rotating the resin residual body 500 corresponding to the closed passages 752c and 752d is determined so that the longer closed passage 752c is located on the front side in the rotation direction. can be prevented from coming into contact with a member such as the molded body extruding rod-shaped portion 9 (see FIG. 2).

Further, as shown in FIGS. 6 and 7, the narrow width portions 7513 and 7523 are formed at the ends of the back side passage 75 (the gate conducting passage 751 and the closed passage 752), so that the molten resin flowing through the narrow portions 7513 and 7523 is The solidified resin quickly hardens and acts as a seal, so that opening of the mating surfaces of the core body 4 and the core divided portion 5 can be suppressed, and the occurrence of burrs in the resin residual body 500 can be suppressed.

Further, when the molded body 30 is extruded from the core body 4, the core split portion 5 directly pushes the molded body 30, so that gate cutting can be performed while the molded body 30 is being pushed out. In addition, since the core dividing portion 5 pushes the end surface 303 (see FIGS. 9 and 10) of the molded body 30 where the gate 77 is located, it is possible to push the position closest to the gate 77, thereby 500 can be easily cut at the gate 77 position.

Further, since the rotating shaft 10 is rotated by the guide grooves 12 formed in the rotating shaft 10 and the guide protrusions 13 fitted therein, the rotating shaft 10 can be rotated without providing an electric part such as a motor. , the electrical configuration of the injection molding apparatus 1 can be simplified.

It should be noted that the present disclosure is not limited to the above embodiments, and various modifications are possible. In the above-described embodiment, an example is shown in which the back side passages 75 are formed in the portions 5a and 5b of the divided core portions 5a to 5d, but the back side passages 75 may be formed in all of the divided core portions 5a to 5d. . In this case, the fitting portions 57 and 58 shown in FIG. 4 may not be formed. This also prevents opening of the mating surfaces between the core split portion 5 and the cavity 2 .

Further, in the above-described embodiment, an example in which the core split portion 5 is divided into four is shown, but it may be split into any number of pieces, and the outer periphery of the molding space 6 may be formed by a single core split portion without being split. It may surround the entire circumference.

Further, the gate cutting method and the method of taking out the resin residue 500 from the core body 4 are not limited to the above-described embodiments, and any method may be used. For example, in the above-described embodiment, the molded body 30 is extruded by the core dividing portion 5 and the molded body pushing rod-shaped portion 9, and the resin residual body 500 is pushed out by the undercut-shaped portion 15 at the tip of the rod-shaped portion 14 and the spring member 16 for urging it. Although the gate cut is performed by preventing the extrusion of , the gate cut may be performed as follows. That is, the extrusion of the molded body 30 is performed only by the molded body extruding rod-shaped part 9, and the core divided part 5 is stopped when the molded body 30 is started to be extruded, thereby preventing the extrusion of the resin residue 500 by the core divided part 5. do. This also allows gate cutting to be performed during extrusion of the compact 30 . In this case, the residual resin body 500 can be removed from the core body 4 by retracting the core split portion 5 from the core body 4 after the gate cut.

In the above embodiment, the rotary shaft 10 is rotated by the guide groove 12 formed in the rotary shaft 10 and the guide protrusion 13 fitted therein. may

Further, in the above embodiment, the injection molding apparatus 1 having two molding spaces 6 was illustrated, but the number of molding spaces may be one, or three or more.

REFERENCE SIGNS LIST 1 injection molding apparatus 2 cavity 3 core 4 core body 5 core split portion 6 molding space 7 passage 75 rear passage 8 first molded body extruding bar portion 19 extruding plate 20 driving portion

Claims (6)

a cavity;
a core body that is openable and closable with respect to the cavity and forms a molding space for injection-molding a resin molded body with the cavity when the mold is closed;
is provided on the core body side, surrounds the entire outer periphery of the molding space when viewed from the opening and closing direction of the cavity and the core body, and forms a part of the surface of the molding space, and when the mold is closed, the a core split having a mating surface that mates with the surface of the cavity;
a control unit that separates the core split portion from the core body when the mold is opened after injection molding,
A passage for introducing the molten resin into the molding space is formed on a surface of the core split portion opposite to the mating surface,
The core dividing part is
a first acting surface, which is a surface constituting the molding space and on which a force acts in a direction away from the cavity by the molten resin introduced into the molding space;
and a second acting surface, which is a surface forming the passage and on which a force acts in a direction of approaching the cavity by the molten resin flowing through the passage,
The area of the second working surface is greater than or equal to the area of the first working surface,
Injection molding equipment. 2. The injection molding apparatus according to claim 1, wherein the core dividing portion is a molded body pushing portion that pushes out the resin molded body from the core body as it moves in a direction away from the core body when the mold is opened after injection molding. . The passage has a first passage whose end on the downstream side is connected to the molding space and a second passage whose end on the downstream side is closed,
3. The injection molding apparatus according to claim 1, wherein the width of said second passage is smaller than the width of said first passage. The core divided portion is divided into a plurality of parts along the outer periphery of the molding space,
The passage is formed on the opposite side of the part of the core split portion,
The divided portion with passage, which is the divided core portion in which the passage is formed, and the non-divided passage portion, which is the divided core portion in which the passage is not formed, are configured to absorb the force acting in the direction of approaching the cavity. 4. The injection molding apparatus according to any one of claims 1 to 3, further comprising a force transmission portion for transmitting force from the divided passage portion to the non-divided passage portion. It has a shape that prevents a resin residue formed by cooling and solidifying the resin remaining in the passage from being pushed out from the core body, and the resin molding is pushed out from the core body as the resin molded body is pushed out from the core body. an extrusion prevention unit that separates the residual body from the resin molded body;
a residue extruding portion for extruding the resin residue separated from the resin molded body by the extrusion blocking portion from the core body together with the extrusion blocking portion;
a rotating portion that rotates the residual resin extruded from the core body in a direction away from the extrusion blocking portion;
The injection molding apparatus according to any one of claims 1 to 4, further comprising: A plurality of the rotating parts are provided,
The passage has an inter-rotating portion passage that connects between the two rotating portions,
The resin residual body includes an inter-rotating part residual body formed in the inter-rotating part passage,
Using the residue extruding portion as a first residue extruding portion,
a second residue extruding part that extrudes and cuts the inter-rotating part residue from the core body in a state where the extrusion of the resin residue is blocked by the extrusion blocking part;
The first residual body extruding part pushes out the resin residual body from the core body after the inter-rotating part residual body is cut,
6. The injection molding apparatus according to claim 5, wherein the rotating section rotates the resin residue after the inter-rotating section residue is cut.

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