JP2006256285A - Mold for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make, in a two-stage ejection mechanism, each of ejector pin A and ejector pin B to operate independently. <P>SOLUTION: Ejector plates A upper 16 and A lower 17 hold by sandwiching the diameter-enlarged bottom of ejector pin A14, and ejector plates B upper 19 and B lower 20 hold by sandwiching the diameter-enlarged bottom of ejector pin B15. Between ejector plates A lower 17 and B upper 19, ejector plate C22 is arranged. On the sides of ejector plates B upper 19 and C22, magnets 23 and 24 are fixed and both plates 19 and 22 are attracted by magnetic force. Ejector rod 29 penetrates ejector plates B upper 19 and B lower 20 and is tied to ejector plate C22. Stop bolt 28 is inserted into movable-side mounting plate 11, thread-engaged with ejector plate B lower 20 and slides within movable-side mounting plate 11 in the movable range of stroke Sb. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an injection mold having a two-stage ejecting mechanism of an ejector.

  In recent years, plastic molded products have been frequently used in various industrial molded products for the purpose of improving material properties, facilitating parts production, facilitating assembly, reducing weight, and reducing costs, and are mass-produced using injection molding machines. . Some of such plastic molded products have undercuts. An injection mold having a two-stage extrusion mechanism is used for injection molding of such plastic molded products (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). A conventional general injection mold will be described with reference to the drawings. FIG. 2 is a sectional view showing a main part of a conventional injection mold.

  First, the configuration of a conventional injection mold will be described. In FIG. 2, the injection mold has a cavity between a fixed mold and a movable mold which are configured to be openable and closable. Reference numeral 50 denotes main components of the movable mold. The movable mold 50 is formed by stacking and fixing 51 movable side mounting plates, 52 spacer blocks, and 53 movable side receiving plates that are mounted on the movable side of the injection molding machine. Reference numeral 54 denotes a first ejector pin A for projecting a molded product from a movable side mold plate (not shown) on the movable side receiving plate 53, and reference numeral 55 denotes a second ejector pin B.

  56 is on the ejector plate A holding the large diameter bottom portion of the ejector pin A54, and 57 is also below the ejector plate A, and moves up and down between the movable side mounting plate 51 and the movable side receiving plate 53. 58 is on the ejector plate B holding the large-diameter bottom portion of the ejector pin B55, 59 is also below the ejector plate B, and moves up and down between the movable side mounting plate 51 and the movable side receiving plate 53.

  Reference numeral 60 denotes a return pin for returning the ejector plate B upper 58 and lower B 59 to the original position when the mold is closed. Slide in the plate 53. Reference numeral 61 denotes a compression coil spring fitted into a return pin 60 between the ejector plate B 58 and the movable side receiving plate 53. Reference numeral 62 denotes a guide pin that is implanted in the movable side receiving plate 51 and passes through the ejector plate B upper 58 and lower B 59 and receives the bottom surface of the ejector plate A lower 57 at the upper end surface. A compression coil spring 63 is disposed between the ejector plate A upper 56 and the movable side receiving plate 53. Reference numeral 64 denotes an ejector rod of an injection molding machine that pushes up the central portion of the lower 59 of the ejector plate B.

  Next, the operation of this injection mold will be described. The mold is attached to an injection molding machine and heated. After the mold is clamped, molten resin is injected from a resin injection port. Resin fills the cavity from the gate. While the pressure is maintained for a certain time, the resin is cooled and cured. Next, the mold is opened from the parting line, and in accordance with the operation of the ejector rod 64, the ejector plate B upper 58 and lower B 59 are pushed up together with the ejector pin B55 to eject the molded product from the cavity (first stage) Protruding).

When the ejector rod 64 is further projected, the upper surface 58 of the ejector plate B pushes up the bottom surface 57 of the ejector plate A to project the ejector pin A54 (second-stage protrusion). After mold release, the mold closes in preparation for the next molding.
JP-A-2-255314 (page 2, FIG. 1) Japanese Patent Laid-Open No. 5-200806 (page 3-4, FIGS. 1 to 3) 2000-5861 (4th page, FIG. 1)

  However, as explained above, in the conventional two-stage extrusion mechanism of the injection mold, the ejector pin B55 moves first, and then the ejector pin A51 moves together with the ejector pin B55. That is, when the ejector pin A51 moves, the ejector pin B55 must also move. In such a two-stage protrusion operation, the stroke of the ejector pin becomes longer than necessary. For example, when the slide core is operated by the ejector pin, the slide core must also move more than necessary. , The mold life is disadvantageous.

  The present invention has been made to solve such a conventional problem, and an object thereof is to provide an injection mold in which the ejector pin A and the ejector pin B can be independently operated. It is.

  Means of the present invention for solving the above-described problem comprises a fixed mold and a movable mold, and a first ejector is provided between the movable mounting plate and the movable receiving plate of the movable mold. An injection mold having a first ejector plate for holding a pin and a second ejector plate for holding a second ejector pin, wherein the ejector pin is configured to be operated by a two-stage ejecting mechanism. By disposing a third ejector plate detachably connected to the second ejector plate between the first ejector plate and the second ejector plate, and pushing up the third ejector plate, The second ejector pin and the first ejector pin are operated independently of each other. To.

  Further, the stroke of the second ejector pin is regulated by a stop bolt which is inserted into a hole having a counterbore on the movable side mounting plate and fixed to the second ejector plate.

  According to the present invention, since the ejector pin A and the ejector pin B can be independently operated, an injection mold that moves the slide core using the ejector pin can be made. Therefore, it is effective as a protruding structure of an injection mold for molding a molded product having a thin wall.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part showing an injection mold according to an embodiment of the present invention. First, the configuration of this mold will be described. In FIG. 1, the fixed mold is omitted. Reference numeral 10 denotes a movable side mold, 11 is a movable side mounting plate, 12 is a spacer block, and 13 is a movable side receiving plate. Reference numeral 14 denotes an ejector pin A which is a first ejector pin, and 15 denotes an ejector pin B which is a second ejector pin.

  Reference numerals 16 and 17 denote an ejector plate A that is a first ejector plate that holds the large-diameter bottom portion of the ejector pin A14, and an A plate that is below the ejector pin A14. Reference numerals 19 and 20 denote upper and lower ejector plates B, which are second ejector plates that sandwich the large diameter bottom portion of the ejector pin B15, and both plates are screwed together with bolts. Reference numeral 22 denotes an ejector plate C, which is a third ejector plate, which is disposed between the ejector plate A lower 17 and the ejector plate B upper 19 and is detachably connected to the ejector plate B 19 by a magnet described later. Has been. All of these plates move up and down between the movable mounting plate 11 and the movable receiving plate 13.

  Reference numerals 23 and 24 denote magnets fixed to the side surface of the ejector plate B upper 19 and the side surface of the ejector plate C22. The upper surface of the ejector plate B 19 and the bottom surface of the ejector plate C22 are attracted by the magnetic force of the magnets 23 and 24. It is connected. Reference numeral 25 denotes a return pin for returning the ejector plate C22 to its original position when the mold is closed. The return pin 25 is held by the ejector plate 22 and slides within the ejector plates A16, A17 and the movable side receiving plate 53. Move. A compression coil spring 26 is fitted into a return pin 25 between the ejector plate A 16 and the movable side receiving plate 13.

  Reference numeral 27 denotes a guide pin which is held at the upper 19 and the lower 20 of the ejector plate B and receives the bottom surface of the lower 17 of the ejector plate A at the upper end surface. The ejector plate A upper 16 and A lower 17 move up and down by the stroke Sa between the guide pin 27 and the movable side receiving plate 13. Reference numeral 28 denotes a stop bolt inserted through a hole 28a having a counterbore on the movable side mounting plate 11 and fixed to the lower 20 of the ejector plate B. The stop bolt 28 slides within the movable side mounting plate 11 within a movable range of the stroke Sb. By doing so, the stroke of the ejector pin B15 is regulated. Reference numeral 29 denotes an ejector rod which passes through the upper 19 and the lower 20 of the ejector plate B and is fixed to the center bottom surface of the ejector plate C22 with 30 bolts.

  Next, the operation of this injection mold will be described. The molten resin is cooled and cured after being poured into the mold. Next, the mold is opened, and the ejector plate C22 is pushed up according to the operation of the ejector rod 29. At this time, the upper and lower ejector plates B and 20 are lifted together with the ejector plate C22 by the magnets 23 and 24 to eject the ejector pin B15 (first-stage ejection). When the ejector rod 29 further rises and reaches the stroke Sb, the upper 19 and lower 20 B of the ejector plate B are stopped by the action of the stop bolt 28.

  Thereafter, the magnet 24 is detached from the magnet 23, the ejector plate C22 is further raised, and the lower ejector plate A 17 is pushed up. Along with this, the ejector pin A14 is pushed up by the stroke Sa (second-stage protruding). After the molded product is released, each ejector plate is returned to the original position by the return pin 25 and the coil spring 26 when the mold is closed in preparation for the next molding. Magnets 23 and 24 are also connected.

  Next, effects of the embodiment of the present invention will be described. Since the ejector plate C22 that can be attached to and detached from the upper and lower ejector plates B and 20 by the magnets 23 and 24 is provided, the ejector pin B15 is pushed up by the first half of the ejector rod 29 and stopped there. The ejector pin A15 can be pushed up. In this way, the ejector pins A14 and B15 can be operated independently. Therefore, for example, in the case of an injection mold having a slide core, it can be used as a mechanism for opening the slide core by the first push-up and releasing the molded product by the second push-up.

  In the embodiment described above, the attaching / detaching operation between the ejector plate B 19 and the ejector plate C22 is performed by the action of the magnets 23 and 24. However, instead of this magnet, a parting lock, a best lock, etc. You may make it perform by.

  The injection mold of the present invention can be widely applied as a two-stage extrusion mechanism for a molded product having a thin wall.

It is principal part sectional drawing which shows the injection mold which is embodiment of this invention. It is principal part sectional drawing which shows the conventional injection molding die.

Explanation of symbols

14 Ejector pin A
15 Ejector pin B
10 Movable mold 16 Ejector plate A upper 17 Ejector plate A lower 19 Ejector plate B upper 20 Ejector plate B lower 22 Ejector plate C
23, 24 Magnet 29 Ejector rod 28 Stop bolt 28a Hole Sb Stroke

Claims (2)

  A first ejector plate and a second ejector which are composed of a fixed mold and a movable mold, and hold a first ejector pin between the movable mounting plate and the movable receiving plate of the movable mold. In an injection mold having a second ejector plate for holding a pin and configured to operate the ejector pin by a two-stage ejection mechanism, the first ejector plate and the second ejector plate A third ejector plate that is detachably connected to the second ejector plate is disposed therebetween, and the third ejector pin is pushed up so that the second ejector pin and the first ejector pin are An injection mold characterized by being operated independently. 2. The injection molding according to claim 1, wherein a stroke of the second ejector pin is regulated by a stop bolt that is inserted into a hole having a counterbore in the movable side mounting plate and fixed to the second ejector plate. Mold.

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