JP2010110916A - Mold for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mold a molded article with an undercut without requiring complicated members such as a jig by a smooth operation. <P>SOLUTION: In a mold M1 for injection molding constituting a cavity of the molded article 1 by a fixing side core 3 of a fixing side mold plate 4, a movable side core 10 at the side of a movable side mold plate 8, and a plurality of slide cores 7, an angular pin guide hole 22 through which an angular pin 11 is inserted is provided in an individual slide core 7 wherein, by push-out operation in the mold opening/closing direction by an ejector pin 17 for the slide core, displacement separating in the oblique direction along the angular pin 11 from the molded article 1 is given to the individual slide core 7 to achieve a mold releasing operation of the slide core 7 in the undercut 1a of the molded article 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection molding technique, for example, a technique effective when applied to molding of a molded article having an undercut.

  For example, an injection molding technique is widely used as a technique for mass-producing products having complicated shapes. By the way, the concavo-convex shape in the direction intersecting the mold opening direction in the outer shape of the molded product is called an undercut. When a cavity is formed only by a normal fixed mold and a movable mold, this undercut portion is used for mold opening and mold release. It becomes an obstacle to operation.

  Therefore, conventionally, for molding of a molded product including an undercut, as in Patent Document 1, a slide core that constitutes a cavity portion corresponding to the undercut is movably provided independently of a fixed mold and a movable mold. By adopting a mold structure and retreating the slide core in a direction perpendicular to the mold opening direction at the time of mold release, we are trying to realize a smooth mold release of a molded product having an undercut.

  In the case of such a mold structure corresponding to the undercut, the slide core is disposed on the movable mold side, the flange is provided on the slide core, the flange is pressed by the guide rail, and the mold opening direction It is prevented from moving in the mold opening direction by being guided in a direction orthogonal to the mold opening direction.

  The slide core is moved in a direction orthogonal to the mold opening direction at each molding shot by contacting an angular pin provided on the fixed mold. Although it is possible to operate the slide core hydraulically without using an angular pin, the flange of the slide core is still held by the guide rail so as not to be separated from the movable side template.

  In order for the slide core to operate smoothly, a clearance is required on the sliding surface between the flange of the slide core of the movable side template and the guide rail. However, since there is this gap, the slide core tilts with respect to the sliding surface and does not move in parallel, so-called galling occurs, and there is a concern that the slide core cannot slide.

In addition, there is a concern that the temperature of the slide core rises during molding, the flange portion thermally expands and adheres closely to the rail side, and there is no gap for sliding.
As described above, when the slide core is displaced by the rail and the flange in the direction perpendicular to the mold opening direction, the technical problem is that the mold does not operate normally because the slide core does not slide smoothly. is there.

For this reason, as a molding method that does not use a movable mechanism such as a slide core or a guide rail, for example, as disclosed in Patent Document 2, a split core that constitutes the entire cavity is arranged in the outer mold and molded. However, if the placing core is disassembled and removed from the molded product after it is pushed out from the outer mold, it must be disassembled in a certain direction using a jig. There is a technical problem that it becomes unstable and deforms the molded product.
JP 2007-144755 A JP 11-291303 A

  The objective of this invention is providing the injection molding technique which can shape | mold the molded article which has an undercut by smooth operation | movement, without requiring complicated members, such as a jig | tool.

The present invention is an injection mold having a cavity for molding a molded article having an undercut,
A stationary mold constituting a part of the cavity;
A movable mold that constitutes a part of the cavity and is movable in a mold opening direction with respect to the fixed mold;
A slide core which is held by the movable mold and forms a portion corresponding to the undercut of the molded product of the cavity;
A slide core moving mechanism that moves the slide core in a direction crossing the mold opening direction in conjunction with the mold release operation of the molded product;
An injection mold including the above is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding technique which can shape | mold the molded article which has an undercut by smooth operation | movement, without requiring complicated members, such as a jig | tool, can be provided.

  In the first aspect of the present embodiment, after mold opening, injection molding that molds a molded product having an undercut by displacing the slide core in a direction crossing the mold opening direction in synchronization with the operation of pushing the slide core to the fixed side. Disclose the mold.

  In the second aspect, in the first aspect described above, two angular pins are provided for each slide core as a mechanism for displacing the slide core in a direction crossing the mold opening direction in synchronization with the operation of pushing the slide core to the fixed side. An injection mold having a slide core that is provided and moves following the angular pin is disclosed.

The third aspect discloses an injection mold in which the slide core and the angular pin in the second aspect are provided on the movable side.
According to a fourth aspect, in the second aspect or the third aspect, there is a slide core in which a hole through which the angular pin passes is formed in an elliptical shape with a width of the diameter of the angular pin, and the slide core is fixed at the initial stage of extrusion. Disclosed is an injection mold that moves in a direction and then moves diagonally.

  In the fifth aspect, in the fourth aspect, as a mechanism for driving the slide core, a sleeve pin that abuts on the lower surface of the slide core, and the sleeve pin is provided inside the sleeve pin independently of the sleeve pin, and the tip portion is a sleeve of the slide core. An injection mold having a sleeve center pin inserted in a center pin guide hole is disclosed. In this injection mold, when the slide core is displaced by the sleeve pin at the time of mold release, the slide core is displaced in the mold opening direction by the insertion length of the tip of the sleeve center pin with respect to the sleeve center pin guide hole. Then, it is displaced in the tilt direction following the angular pin.

In the sixth aspect, in the injection mold having the slide core disclosed in the second aspect, when the mold is clamped, the slide core contact slope inclined in the mold opening / closing direction provided on the fixed side and the slide core contact slope are in contact with each other. A configuration in which a slide core having a fixed mold contact slope is in contact with each other is disclosed.
(Function)
In the first aspect described above, the molded product having the undercut is subjected to a mold release operation in which the slide core forming the undercut is moved obliquely away from the movable mold in the fixed direction after resin injection, cooling, and mold opening. After being molded.

  In the second aspect and the third aspect described above, in the first aspect, after the mold is opened, the slide core pushed out by the push-out mechanism that pushes in the fixed side direction is replaced with two angular pins provided for each slide core. The slide core is released from the mold by moving in an oblique direction away from the movable mold and moving away from the molded product.

  In the fourth aspect described above, the hole for passing two angular pins provided for each individual slide core is an ellipse with the width of the angular pin, so that the slide core is shaped by a certain distance during mold release operation. By moving in the opening direction and then moving in an oblique direction following the angular pin, the slide core can be operated to assist the mold release operation in the mold opening direction.

  In the fifth aspect described above, the displacement in the mold opening direction of the slide core in the initial stage of the mold release operation is reliably maintained by the insertion length of the tip portion of the sleeve center pin with respect to the sleeve center pin guide hole, and thereafter the angular pin Accordingly, the slide core can be displaced in the tilt direction, so that it is possible to reliably assist the mold release operation in the mold opening direction by the slide core.

  In the above-described sixth aspect, in the mold clamping state, the slide core is brought into contact with the fixed mold at an inclined surface, so that a part of the mold clamping force moves the movable slide core in a direction orthogonal to the mold opening direction. The position of the slide core can be stably maintained against the filling pressure of the resin during molding.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIG. 1 is a cross-sectional view showing an example of the overall configuration of an injection mold according to an embodiment of the present invention, and FIGS. 2 and 3 show the mold opening and release of the injection mold according to the present embodiment. It is sectional drawing which shows type | mold operation | movement in order of a process.

FIG. 1 shows the clamping state of the injection mold M1 of the present embodiment, and the illustration of the resin pumping path to the cavities such as sprue, runner, and gate is omitted.
The injection mold M1 of the present embodiment will be described as an example of a three-plate mold as an example. This injection mold M1 is composed of the following parts in order to produce the molded product 1.

  That is, the injection mold M1 of the present embodiment includes a fixed mounting plate 2, a fixed side insert 3, a fixed side mold plate 4, a locking block 5, a runner stripper plate 6, a slide core 7, a movable side mold plate 8, a spacer. Block 9, movable side insert 10, angular pin 11 provided for each of slide cores, ejector rod 12, ejector plate upper 13, ejector plate lower 14, sleeve center plate 15, ejector pin 16 for molded product, individual Each slide core includes two slide core ejector pins 17 and a movable mounting plate 18.

  A substantially concave fixed side nest 3 constituting the upper part of the cavity, which is a molding space for molding the molded product 1, has a concave surface facing downward at the center of the surface of the fixed side template 4 facing the movable side template 8. A plurality of locking blocks 5 are arranged at symmetrical positions sandwiching the stationary side insert 3 with the slide core contact slope 5a facing inward.

On the surface of the movable side mold plate 8 facing the fixed side mold plate 4, a mold plate recess 8a having a depth into which the locking block 5 or the like on the fixed side mold plate 4 is inserted is formed at the center of the mold plate recess 8a. The convex movable side nest 10 constituting the lower part of the cavity is arranged.

  On both sides of the movable side insert 10, there are a plurality of slide cores 7 (for example, a halved structure in which the cavity is divided into two in the circumferential direction) constituting the side surface of the cavity corresponding to the undercut 1a of the molded product 1. The movable-side insert 10 is disposed so as to surround the movable-side insert 10.

  A stationary mold contact slope 7 a having an inclination angle corresponding to the slide core contact slope 5 a of the rocking block 5 is formed on the back side opposite to the cavities of the plurality of slide cores 7.

  At the time of mold clamping, the force in the mold clamping direction is individually increased in the direction perpendicular to the mold clamping direction by the slide core contact slope 5a of the locking block 5 and the slope contact portion A of the fixed mold contact slope 7a of the slide core 7. It is converted into thrust that presses the slide core 7, the plurality of slide cores 7 are urged in a direction approaching each other, and fixed to a fixed position (molding position) around the convex movable side insert 10, and the fixed side insert 3. A cavity for molding the molded product 1 together with the movable side insert 10 is configured.

  The movable side insert 10 is formed with a plurality of through holes penetrating in the mold clamping (die opening) direction, and a plurality of molded product ejector pins 16 enter and exit the cavity through the through holes. The mold release operation of pushing up the molded product 1 from below is possible.

  A through hole through which the slide core ejector pin 17 enters and exits is formed in a mold clamping (die opening) direction at a position facing the lower surface of each slide core 7 in the template recess 8a of the movable template 8. The upper ends of the slide core ejector pins 17 are in contact with the lower surfaces of the individual slide cores 7 through the holes. The slide core 7 can be pressed in the mold opening direction by projecting the slide core ejector pin 17.

  The molded product ejector pin 16 and the slide core ejector pin 17 are provided with a flange-shaped head at the lower end, and this head is sandwiched between a common ejector plate upper 13 and ejector plate lower 14. The vertical movement is synchronized with the mold opening direction.

  An ejector rod 12 that passes through the center of the movable mounting plate 18 is connected to the back side of the lower ejector plate 14 that supports the lower ends of the ejector pin 16 for the molded product and the ejector pin 17 for the slide core. The vertical movement of the molded product ejector pin 16 and the slide core ejector pin 17 is controlled via the lower ejector plate 14 by thrust.

  In the case of the injection mold M1 of the present embodiment, around the movable side insert 10, a plurality of angular pins 11 whose lower ends are planted on the bottom surface of the template recess 8a are centered on the moveable insert 10. It is arranged to have an inclination angle that spreads in the mold opening direction.

Each slide core 7 is provided with an angular pin guide hole 22 (first guide hole) that fits into the angular pin 11.
In the injection mold M1 of the present embodiment, the plurality of slide cores 7 constitute, for example, a side surface of the cavity (molded surface of the undercut 1a) by dividing into left and right parts, and each slide core 7 has a movable side insert. Two parallel angular pins 11 having a symmetric inclination angle about 10 are inserted.

The individual slide cores 7 pushed out by the slide core ejector pins 17 and lifted away from the movable side mold plate 8 are moved away from the cavity (molded product 1) by the parallel movement guided by the two angular pins 11. It is configured to move in an oblique direction.

For this reason, in the injection mold M1 of the present embodiment, a guide rail or the like for guiding the slide core 7 in a direction orthogonal to the mold opening direction is completely unnecessary.
Hereinafter, the operation of the injection mold M1 of the present embodiment will be described.

The injection mold M <b> 1 is closed as shown in FIG. 1 at the time of molding, and is constituted by a cavity including a fixed side insert 3, a movable side insert 10 and a plurality of slide cores 7.
At this time, the fixed mold contact slope 7a of the slide core 7 is in contact with the locking block 5 of the fixed side mold plate 4 having the slide core contact slope 5a inclined in the mold opening / closing direction at the slope contact portion A, so that the movable side The slide core 7 is biased in a direction approaching the insert 10 and receives the force that the slide core 7 is pushed outward of the cavity by the resin injection pressure when the resin is injected into the cavity.

  Then, after the resin injection molding for molding the molded product 1 by pumping and filling the resin into the cavity through a sprue, runner, gate, etc. (not shown), the mold opening for separating the movable mold plate 8 from the fixed mold plate 4 is performed. Immediately after opening the mold, the molded product 1 remains on the movable mold 8 side in a state surrounded by the movable insert 10 and the slide core 7 as shown in FIG.

After the above-described mold opening is completed, when a mold releasing operation is performed in which the ejector rod 12 is pushed out in the fixed direction by an unillustrated extrusion device of the molding machine, the state shown in FIG.
In this mold release operation, the ejector pin 16 for the molded product and the ejector pin 17 for the slide core, whose flange portions are fixed to the upper ejector plate 13 and the lower ejector plate 14, are fixed by the ejector rod 12 attached to the lower ejector plate 14. When extruded sideways, the molded product ejector pin 16 and the slide core ejector pin 17 protrude from the movable side insert 10 and the template recess 8a, and the molded product 1 and the slide core 7 are moved in the fixed direction.

  At this time, in the case of the present embodiment, the molded product 1 is displaced in the fixed direction along the mold opening direction, but the individual slide cores 7 having the angular pin guide holes 22 fitted into the angular pins 11 are The slide core ejector pin 17 is guided by the two angular pins 11 in accordance with the pushing displacement in the mold opening direction, and is movable obliquely in the direction of the inclination angle of the angular pin 11 in the releasing direction away from the molded product 1. Ascend from the side template 8.

  Thus, by adopting the structure of the injection mold M1 of the first embodiment, the slide core 7 that is moved following the two parallel angular pins 11 provided for each individual slide core 7 is: Only sliding between the two angular pin guide holes 22 provided for each slide core and the two angular pins 11 does not slide with the movable side mold plate 8 without causing malfunction such as galling. The molded product 1 operates so that the direction in which the molded product 1 is removed from the undercut 1a is also constant, and can be released from the molded product 1 to form an undercut with respect to the molded product 1 (ie, the unevenness of the undercut 1a). Only the mold release operation of displacing the slide core 7 in the direction orthogonal to the mold opening / closing direction can be realized).

That is, it is possible to form a molded product having an undercut by a smooth operation without requiring a complicated member such as a jig.
In this specification, “the slide core 7 forms an undercut” means that “the slide core 7 is displaced in a direction intersecting the mold opening / closing direction by an amount corresponding to the unevenness of the undercut 1 a of the molded product 1. It means “to realize mold movement”.
[Embodiment 2]
FIG. 4 is a cross-sectional view showing a clamping state of an injection mold according to another embodiment of the present invention, and FIG. 5 is an angular pin guide hole of a slide core that constitutes the injection mold according to the present embodiment. It is a fragmentary sectional view which shows the shape.

  6 is a cross-sectional view showing the mold opening state of the injection mold according to the present embodiment, and FIGS. 7 and 8 are cross sections showing the mold release operation state of the injection mold according to the present embodiment in the order of steps. FIG. 9 is a partial cross-sectional view showing the release operation state of the injection mold according to the present embodiment in the order of steps.

In the injection mold M2 of the second embodiment, portions common to the above-described injection mold M1 are denoted by common reference numerals, and redundant description is omitted.
In the mold structure of the injection mold M1 of the first embodiment illustrated in FIG. 1 described above, when the molded product 1 to be molded is extruded by the extrusion device of the molding machine, an undercut is formed simultaneously with the extrusion. The slide core was displaced in the diagonal direction.

  On the other hand, in the injection mold M2 of the second embodiment, the slide core 7 is displaced in the mold opening / closing direction at the initial stage of extrusion (mold release operation), and then moved away from the molded product 1 in an oblique direction. An example of realizing an undercut operation is shown.

  For this reason, in the injection mold M2 of the second embodiment, first, as illustrated in FIG. 5, instead of the above-described angular pin guide hole 22, an angular pin guide long hole 22A ( A first guide hole) is provided in each slide core 7.

  FIG. 5 shows a cross section perpendicular to the axial direction of the angular pin 11. The angular pin guide long hole 22A is provided in the slide core 7 so that the long axis of the angular pin guide long hole 22A is parallel to a plane including the mold opening / closing direction and the axial direction of the inclined angular pin 11. .

  The angular pin guide long hole 22 </ b> A is an ellipse having a width of the diameter of the angular pin 11. At this time, when the gap ΔL in the major axis direction of the angular pin 11 and the angular pin guide elongated hole 22A is set to a displacement amount D (described later) in the mold opening / closing direction in the initial stage of mold release of the slide core 7, the angular pin 11 When the inclination angle is α with respect to the mold opening / closing direction, ΔL = D · sin α is determined.

Further, the width in the short axis direction of the angular pin guide long hole 22A is set to be slightly larger than the outer diameter dimension of the angular pin 11 so as not to prevent the displacement of the slide core 7.
As a result, the slide core 7 can be freely displaced corresponding to the displacement amount D in the mold opening and closing direction, but the two slide cores 7 do not move in the short axis direction (direction perpendicular to the paper surface of FIG. 4). Guided by the angular pin 11.

Note that this displacement amount D is the distance of relative free allowance. The displacement amount D is a necessary and sufficient distance for releasing the bottom surface of the molded product 1 from the movable side insert 10 in the vertical direction.
Further, in order to release the molded product 1 from the movable side, the molded product ejector pin 16 for pushing out the molded product 1 is left as it is, and the slide core 7 is pushed out by a sleeve push-out mechanism described later.

  By adopting the mold structure of the injection mold M2 of the second embodiment, the slide core 7 that is fitted to the side surface of the molded product 1 by the undercut 1a and displaced by the displacement amount D in the mold opening direction, Since the molded product ejector pin 16 serves to assist the mold release operation of the molded product 1 from the movable insert 10, an ejector for releasing the molded product 1 from the movable insert 10 near the slide core 7. There is an advantage that it is not necessary to provide a pin.

  The sleeve push-out mechanism is provided for each slide core 7 to be pushed out, and includes two sleeve pins 19 that come into contact with the bottom surface of the slide core 7 and a sleeve center pin 20 provided inside the sleeve pin 19. I have.

  The outer sleeve pin 19 is fixed at the lower end side to the upper ejector plate 13 and the lower ejector plate 14 that are the same as the ejector pin 16 for the molded product, similarly to the above-described ejector pin 17 for the slide core. It operates in synchronism with the ejector pin 16 for a molded product by this thrust.

  On the other hand, the lower end of the sleeve center pin 20 provided inside the sleeve pin 19 is fixed to the movable mounting plate 18 by sandwiching the flange portion between the sleeve center plate 15 and the movable mounting plate 18.

  Further, the sleeve center pin 20 protrudes from the tip of the sleeve pin 19 whose upper end abuts on the lower surface of the slide core 7 by a length corresponding to the above-mentioned displacement amount D in the clamped state, and is provided on the slide core 7 side. The length is set to be inserted into the sleeve center pin guide hole 23 (second guide hole).

  Therefore, when the sleeve pin 19 (the ejector pin 16 for molded product) is displaced in the mold opening direction by the releasing operation, the sleeve center pin 20 is relatively pulled into the sleeve pin 19.

  In the second embodiment, two sleeve pins 19 and a sleeve center pin 20 are arranged for each slide core 7. The sleeve pin 19 and the sleeve center pin 20 depend on the size of the slide core 7. Three or more may be arranged.

Hereinafter, the operation of the injection mold M2 of the second embodiment will be described with reference to FIG. 6, FIG. 7, FIG. 9, FIG.
First, in the mold clamping state of FIG. 4, the fixed side insert 3, the movable side insert 10 and the plurality of slide cores 7 are in close contact with each other to form a cavity for forming the molded product 1. The sleeve center pin 20 is inserted into the sleeve center pin guide hole 23 by a displacement amount D.

  Further, as shown in FIG. 5, the pin outer diameter B1 which is the upper surface side of the angular pin 11 (the opposite side of the pin outer diameter lower surface B2) is the guide hole inner diameter which is the upper end surface in the major axis direction of the angular pin guide long hole 22A. It is in a state of being in close contact with the upper surface C1.

From this state, after the molded product 1 is molded, first, as shown in FIG. 6, mold opening is performed.
Further, the mold release operation is started as shown in FIG. In the case of the second embodiment, the slide core 7 can be freely moved in the mold opening / closing direction by the displacement amount D by the gap ΔL of the angular pin guide long hole 22A. A displacement amount D is vertically displaced in the opening direction, and the bottom surface of the molded product 1 is released from the movable side insert 10.

  FIG. 7 shows a displacement D in which the molded product 1 and the slide core 7 are inserted into the sleeve center pin guide hole 23 of the slide core 7 with the molded product ejector pins 16 and the sleeve center pins 20 in the fixed direction. Only the extruded state is shown. In this state, the distal end portion of the sleeve center pin 20 is at a position just removed from the sleeve center pin guide hole 23 of the slide core 7, and the slide core 7 is in a state where it can move in an oblique direction.

  Further, when the ejector pin 16 and the sleeve pin 19 fixed to the common ejector plate upper 13 and ejector plate lower 14 are extruded in the fixed direction by the extrusion device of the molding machine, as shown in FIG. 7 is displaced in an oblique direction away from the molded product 1 along the angular pin 11, and the part of the undercut 1a is also released.

FIG. 9 shows the relationship between the angular pin 11 and the angular pin guide slot 22A in the order of operation during the mold release operation illustrated in FIGS. 7 and 8 described above.
Before the mold release operation illustrated in the upper left of FIG. 9, the pin outer diameter upper surface B1 of the angular pin 11 is in close contact with the guide pin inner diameter upper surface C1 side of the angular pin guide long hole 22A as shown in FIG. A gap ΔL is formed between the lower pin outer diameter lower surface B2 and the guide pin inner diameter lower surface C2 of the angular pin guide hole 22.

  Then, at the initial stage of mold release illustrated in the center of FIG. 9, the slide core 7 moves vertically by a displacement amount D by guidance in the mold opening direction by the sleeve center pin 20 and the sleeve center pin guide hole 23. The pin outer diameter lower surface B2 of the angular pin 11 and the guide hole inner diameter lower surface C2 of the angular pin guide long hole 22A are in close contact with each other.

  Further, when the slide core 7 is lifted, the slide core 7 is molded as shown in the inclined displacement direction E of the arrow, following the pin outer diameter lower surface B2 of the angular pin 11, as illustrated in the lower right of FIG. Displacement is carried out in an oblique direction so as to be away from the undercut 1a of 1 and the release operation is completed.

  Therefore, by adopting a mold structure such as the injection mold M2 of the second embodiment, the slide core 7 is displaced by the displacement amount D in the fixed side direction, and the molded product 1 is released from the movable side insert 10. After that, the slide core 7 is displaced in an oblique direction so as to be separated from the molded product 1 following the two angular pins 11 provided for each individual slide core 7. Therefore, it is not necessary to dispose an ejector pin for a molded product for releasing the mold.

  Further, during the movement period of the displacement amount D by the slide core 7, the displacement of the slide core 7 in the vertical direction (mold opening / closing direction) is stably maintained by the fitting of the sleeve center pin 20 and the sleeve center pin guide hole 23. Therefore, during the mold release operation between the displacement amount D by the slide core 7, problems such as the slide core 7 being detached from the molded product 1 and the mold release operation becoming unstable are reliably prevented.

Similarly to the above-described first embodiment, the slide core 7 is displaced only by sliding between the two angular pin guide long holes 22A provided for each slide core 7 and the two angular pins 11, By sliding along the two angular pins 11 without sliding with the movable side mold plate 8, the undercut can be formed by moving away from the molded product 1. .
[Embodiment 3]
FIG. 10 is a cross-sectional view showing a configuration of the injection mold according to still another embodiment of the present invention in a clamped state. FIG. 11 and FIG. 12 are partial cross-sectional views showing a mold release operation of an injection mold that is still another embodiment of the present invention.

In the third embodiment, an example in which the inclination angle of the angular pin 11 can be changed will be described.
As exemplified in the above-described second embodiment, the slide core 7 is displaced obliquely along the angular pin 11 by the extrusion, thereby realizing the mold release operation corresponding to the undercut 1a. The shape of the undercut 1a is different for each type.

  Therefore, in the injection mold M3 of the third embodiment, the slide core 7 can be changed by changing the inclination angle of the angular pin 11 in the operation in which the slide core 7 is displaced following the two angular pins 11. It was set as the structure which can change the speed (release speed from undercut 1a) which forms undercut.

  In the injection mold M3 of the third embodiment, as illustrated in FIG. 10, the pocket 8b is opened in the movable side mold plate 8 at the portion where the angular pin 11 is fixed, and the angular shape is such that the pocket 8b is inserted. An angular pin retainer 21 in which a pin hole 21 a for passing the pin 11 is processed is created and fixed to the pocket 8 b of the movable side template 8.

  That is, the injection mold M3 of the third embodiment is configured such that the angle of the angular pin 11 can be changed by changing to the angular pin retainer 21 having a different angle of the pin hole 21a through which the angular pin 11 passes.

FIGS. 11 and 12 show the movement of the slide core 7 when the angle of the pin hole 21a of the angular pin retainer 21 (that is, the inclination angle of the angular pin 11) is changed.
The relationship between the angle α1 of the angular pin 11 in FIG. 11 and the angle α2 of the angular pin in FIG. 12 is α1 <α2, and when extruded to the fixed side, the molded product 1 in the case of the angle α2 in FIG. The distance L2 between the slide cores 7 is larger than the distance L1 in the case of the angle α1 in FIG. Further, when the value of the angle α is increased, the speed at which the slide core 7 is separated from the molded product 1 is increased.

  Therefore, by adopting the mold structure of the injection mold M3 of the third embodiment, it is possible to form an optimal undercut corresponding to the shape of the undercut 1a regardless of the shape of the undercut 1a of the molded product 1. it can.

As described above, according to each aspect of each of the above-described embodiments of the present invention, the following effects can be obtained.
According to the first aspect, when the molded product having the undercut is formed by the slide core, the slide core is not pressed against the movable mold, so that the molded product is separated from the movable mold after the mold is opened, and the molded product is separated from the molded product. It is formed by being pushed out by an extruding mechanism for releasing the mold.

Therefore, since the slide core does not slide with the movable mold plate, it is possible to prevent mold trouble without generating galling.
According to the second aspect, when a molded product having an undercut is formed by a slide core, the slide core is extruded together with the molded product by an extrusion mechanism that extrudes in a fixed side direction after mold opening. It is moved following two angular pins.

  Therefore, the slide core only needs to slide with the two angular pins, and does not slide with the movable mold plate, so that no galling is generated and the mold trouble is prevented, and the slide core is moved following the two angular pins. An undercut can be formed by making the drawing direction constant and moving away from the molded product.

  According to the third aspect, when a molded product having an undercut is formed with a slide core, the slide cores pushed out by the push-out mechanism that pushes out in the fixed side direction after the mold opening are provided for each slide core. In order to move along the angular pin, the slide core and the two angular pins are provided on the movable side.

  Therefore, the slide core can be moved only by sliding with the two angular pins, and does not slide with the movable mold plate, so that no galling is generated and a mold trouble is prevented, and the slide core is moved following the two angular pins. As a result, the undercut can be formed by making the drawing direction constant and moving away from the molded product.

  According to the fourth aspect, when forming a molded product having an undercut with a slide core, the slide core pushes out two sleeve center pins and slide cores provided for each individual slide core that guides the slide core. It is pushed out in the fixed direction by a sleeve-type push-out device composed of two sleeves provided for each slide core. The slide core is provided with an oblong hole for guiding two angular pins provided for each slide core so as not to prevent the slide core from moving in the direction of the fixed side by extrusion. I have to.

Therefore, since the slide core is moved in the fixed direction and does not slide with the movable mold plate, it is possible to prevent mold trouble without generating galling.
According to the fifth aspect, when the molded product having the undercut is formed by the slide core, the slide core is moved to the fixed side by the sleeve pin of the sleeve type extrusion device described in the fourth aspect. In that operation, the slide core moves toward the fixed side by the amount of the sleeve center pin inserted into the sleeve center pin guide hole so as to guide the slide core, and when the sleeve center pin is removed, it moves in an oblique direction following the angular pin. It is.

  Therefore, when the slide core moves toward the fixed side, the molded product with the undercut is released from the movable side, and moved according to the two angular pins provided for each slide core, so that the pulling direction is constant. The undercut can be formed away from the formed product.

  According to the sixth aspect, when a molded product having an undercut is formed by a slide core, the slide core has a fixed mold having a slide core contact slope inclined in the mold opening and closing direction, and a fixed metal in contact with the slide core contact slope. The mold is clamped so that the slide core having the mold contact slope comes into contact with the slope, and the resin is injected.

  Therefore, the slide core is not moved by the injection pressure when the resin is injected into the cavity, and an undercut is formed by the extrusion operation described in the fifth aspect, and a high-quality molded product can be manufactured.

Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the cross-sectional shape of the angular pin is not limited to a circle, but may be a non-circular shape such as a polygon or an ellipse.
[Appendix 1]
An injection mold for producing a molded product having an undercut has an extrusion mechanism that separates the slide core that forms the undercut from the movable mold after opening the mold and releases the molded product from the molded product. And injection mold.
[Appendix 2]
The injection mechanism according to appendix 1, wherein the push-out mechanism that pushes out the slide core according to appendix 1 in the fixed direction after mold opening moves the slide core along two angular pins provided for each slide core. Molding mold.
[Appendix 3]
The injection mold according to appendix 2, wherein the slide core and the angular pin according to appendix 2 are provided in a movable mold.
[Appendix 4]
The push-out mechanism that pushes out toward the fixed side after mold opening described in Appendix 1 has a sleeve-type push-out device and a hole through which two angular pins provided for each slide core pass through the slide core. The injection mold according to appendix 1, characterized in that the pin diameter is an ellipse.
[Appendix 5]
The injection mold according to appendix 1, wherein the slide core pushed out by the push-out mechanism that pushes in the fixed side direction after the mold opening according to appendix 1 moves in the fixed side direction at the time of extrusion and is then moved obliquely.
[Appendix 6]
The slide core described in Appendix 2 includes a fixed mold having a slide core contact slope inclined in the mold opening / closing direction at the time of mold clamping, and a slide core having a fixed mold contact slope contacting the slide core contact slope. The injection mold according to appendix 2, characterized in that:

It is sectional drawing which shows an example of the whole structure of the injection mold which is one embodiment of this invention. It is sectional drawing which shows the mold opening and mold release operation | movement of the injection mold which is one embodiment of this invention in order of a process. It is sectional drawing which shows the mold opening and mold release operation | movement of the injection mold which is one embodiment of this invention in order of a process. It is sectional drawing which shows the clamping state of the injection mold which is other embodiment of this invention. It is a fragmentary sectional view which shows the shape of the angular pin guide hole of the slide core which comprises the injection mold which is other embodiment of this invention. It is sectional drawing which shows the mold open state of the injection mold which is other embodiment of this invention. It is sectional drawing which shows the mold release operation | movement state of the injection mold which is other embodiment of this invention in order of a process. It is sectional drawing which shows the mold release operation | movement state of the injection mold which is other embodiment of this invention in order of a process. It is a fragmentary sectional view which shows the mold release operation | movement state of the injection mold which is other embodiment of this invention in order of a process. It is sectional drawing which shows the structural form of the clamping state of the injection mold which is further another embodiment of this invention. It is a fragmentary sectional view which shows the mold release operation | movement of the injection mold which is further another embodiment of this invention. It is a fragmentary sectional view which shows the mold release operation | movement of the injection mold which is further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molded product 1a Undercut 2 Fixed mounting plate 3 Fixed side insert 4 Fixed side mold plate 5 Locking block 5a Slide core contact slope 6 Ranna stripper plate 7 Slide core 7a Fixed mold contact slope 8 Movable side plate 8a Mold plate recess 8b Pocket 9 Spacer block 10 Movable side insert 11 Angular pin 12 Ejector rod 13 Ejector plate upper 14 Ejector plate lower 15 Sleeve center plate 16 Molded product ejector pin 17 Slide core ejector pin 18 Movable mounting plate 19 Sleeve pin 20 Sleeve center pin 21 Angular pin retainer 21a Pin hole 22 Angular pin guide hole 22A Angular pin guide slot 23 Sleeve center pin guide hole A Slope contact portion B1 Pin outer diameter upper surface B2 Pin outer diameter lower surface C1 Guy Die hole inner diameter upper surface C2 Guide hole inner diameter lower surface D Displacement amount E Inclination displacement direction M1 Injection mold M2 Injection mold M3 Injection mold ΔL Clearance between the angular pin 11 and the angular pin guide long hole 22A

Claims (7)

An injection mold having a cavity for molding a molded product having an undercut,
A stationary mold constituting a part of the cavity;
A movable mold that constitutes a part of the cavity and is movable in a mold opening direction with respect to the fixed mold;
A slide core which is held by the movable mold and forms a portion corresponding to the undercut of the molded product of the cavity;
A slide core moving mechanism that moves the slide core in a direction crossing the mold opening direction in conjunction with the mold release operation of the molded product;
An injection mold characterized by including. The injection mold according to claim 1,
The slide core moving mechanism is arranged to be inclined with respect to the mold opening direction, and a slide core pushing pin that pushes the slide core in the mold opening direction, which is fixed to an ejector plate that performs the mold release operation of the molded product. And an angular pin inserted through a first guide hole provided in the slide core. The injection mold according to claim 2,
A plurality of parallel angular pins are inserted into the individual slide cores, and the slide cores are separated from the molded products along the axial direction of the angular pins in synchronization with the mold release operation of the molded products. An injection mold characterized by moving in the direction. The injection mold according to claim 2,
The first guide hole formed in the slide core has an oval shape in which a diameter in a plane formed by an axial direction of the angular pin and the mold opening direction is larger than a diameter in a direction perpendicular to the plane. Present,
The slide core pressed by the slide core push pin is displaced in the mold opening direction at the initial stage of the mold release operation by a distance of the relative free movement margin of the angular pin with respect to the oval first guide hole, An injection mold that is spaced apart from the molded product along the axial direction of the angular pin. The injection mold according to claim 4,
The slide core push-out pin has a cylindrical sleeve pin that abuts on an end surface of the slide core, and a second guide hole that is coaxially disposed inside the sleeve pin and is formed in the slide core in the mold opening direction. An injection mold characterized by comprising a sleeve center pin through which a tip portion is inserted by a distance of the relative free allowance. The injection mold according to claim 2,
An injection mold, wherein a plurality of angular pin retainers for holding the angular pins at different angles are provided in the movable mold in a replaceable manner. The injection mold according to any one of claims 1 to 6,
The injection mold, wherein the slide core is in contact with the fixed mold at a slope inclined in a direction intersecting the mold opening direction at the time of mold clamping.

Images