JPH01271213A - Injection mold - Google Patents

Abstract

PURPOSE:To perform swiftly and easily an exchange of a core, by clamping the core to be fitted to the inside of a mold with a specific setting mechanism. CONSTITUTION:Upon loosely fitting a core 13 into a holding hole 5a of a template 5, a fluid filled out into a closed space 5b is pressurized. With this pressurization, since an inner wall surface of the holding hole 5a is swollen out into the inside of the holding hole 5a and clamps the core 13, the core 13 is held reliably within the template 5. Since the holding hole 5a is restored to a state where the core 13 is fitted loose as before when pressure of a fluid is reduced, the core 13 can be removed smooth through the template 5. It is only necessary that the core 13 corresponding to a kind of a molded product is manufactured by using the template 5 in common and a manufacturing cost of a mold can be reduced drastically. The core 13 can be replaced swiftly and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention mainly relates to a mold for injection molding of plastics, and more particularly, the present invention relates to a mold for injection molding, in which the main part is formed by combining mold plates with inserts attached. This relates to molds for use.

(Prior Art) In plastic injection molding, a mold having an exchangeable insert inside the mold plate is sometimes used in order to be suitable for high-mix, low-volume production. This method reduces mold manufacturing costs by manufacturing and replacing only the insert, which has the cavity and core, instead of manufacturing a mold type for each type of molded product. This is what I did.

Conventionally, for such molds, the insert 113 is fixed to the mold plate 105 using bolts 105a or keys as shown in FIG. 6, or the insert is held by a special mold plate equipped with a hydraulic cylinder. things are used. An example of the front sound using bolts and keys is given in Japanese Patent Application Laid-Open No. 60-107.
An example of the latter using a template with a hydraulic cylinder is described in Japanese Patent Application Laid-open No. 313 (-L).
There will be a first game.

(Problem to be solved by the invention) In the case of 5 molds that do not use bolts or keys to secure the inserts, it is actually time-consuming to replace the inserts. Production of the final molded product in two or two steps:
7th 1. , y2 and τ becomes Yi I'll. The reason is that the inserts must be replaced.1. ' is 9'' which requires disassembling the entire mold: ', 2) High precision mounting position 1. Insert (tfi - firmly) on the mold plate with a constant margin j, -. Because it is attached, the insert can be attached and removed smoothly 4', and there is a risk of damaging the insert or the template when it is removed. Because of (2) and 2), skilled workers with special skills are required to replace the inserts. In reality, it will hardly be used.

On the other hand, when a hydraulic cylinder is installed to hold the insert, the structure of the template is complicated and special.6. -It is inconvenient that it requires a lot of work. 1. From, cylinder C0
Careful maintenance is essential, as failures can be expected, such as the smooth operation of certain parts of the template that are moved back and forth by the Z (611) being jammed with foreign matter.

(Purpose of the Invention) This invention was also made to solve the problem of R mentioned above.In addition to being able to quickly and easily replace the inserts, the structure of the template is simple and there are fewer failures, making it easy to use. Second, it is intended to provide injection molds for the production of a wide variety of molded products 1.1: Thl, a/:.

(To solve the problem), :, In order to achieve the secondary purpose, i, :, Injection K of this invention
K>2 In the injection mold, the insert is attached to the mold plate, and the main part is assembled with the mold plate. l: As part J, a housing hole rA into which the insert wL can be fitted is provided, and a closed space for fluid sealing is provided near the toilet seat in the housing hole with shadow line j7 and R
, communicates with the i1 group V Fl of the 2゛ mold plate; configures a fluid supply channel that opens on the outer surface of the mold plate, fills the fluid into the closed space from this supply channel, and inserts the fluid into the accommodation hole. After insertion, the insert is held by applying pressure with one set of the fluid.

Preferably, a fluid pressurizing means having a screw member and a sliding piston member is provided near the open end of the fluid supply path to seal the fluid in the closed space and the fluid supply path (7).
stomach.

(Function) According to the injection mold of the present invention configured as described above, the mold is loosely fitted into the accommodation hole of the mold plate, and the fluid filled in the closed space is pressurized from 1ζ. Since the inner wall surface of the receiving hole bulges inward and tightens the insert, the insert is reliably held within the template. If the fluid pressure is reduced by 1, the accommodation hole will be 6.
Since the insert returns to the loosely fitted state as shown in the figure, the insert can be smoothly removed from the template.

In addition, in the fluid pressurizing means provided as described above, when the screw member is turned in a specific direction, the piston member advances to increase the pressure of the sealed fluid, and when the screw member is turned in the opposite direction, the piston member is moved forward. Since the fluid pressure is lowered by retreating, the 11th manual operation of tightening and releasing the insert is facilitated.

(Embodiment) FIG. 1 is a plan view of a plastic injection mold according to an embodiment of the present invention, and is partially shown in cross section. This mold A is called a 3-brave stripper plate ejection method, and uses a combination of three templates (plates) 3.4.5 including a stripper plate 4. and is configured to take out the molded product. However, the parts directly involved in resin molding, such as the resin injection route and molding space, are configured as inserts 11, 12, and 13, and these are respectively fitted near the center of the template 3, 4, and 5. It is designed to operate as one unit.

First, the overall configuration and operating mode of the mold A will be explained. An injection device (not shown) is installed in front of the fixed side mounting plate 1 (hereinafter, "front" and "rear" refer to the first, second, and lower sides, respectively). The injection device moves forward, is aligned with the locate ring 17, inserts the nozzle at the tip to the bottom of the recess of the sprue bushing 18, and injects the resin. Also, the movable side mounting plate 8
A mold-clamping/mold-opening cylinder (not shown) whose base end is attached to a fixed frame (not shown) is connected to the rear thereof, and the mounting plate 8 is moved back and forth by expansion and contraction of the cylinder. . An ejector cylinder (not shown) is further fixed to the rear surface of the mounting plate 8, and its telescopic rod can extend forward from the central opening of the mounting plate 8.

Since the fixed side mounting plate 1 is fixed to the diary fixing frame, it will not move together with the locate ring 17, sprue bush 18 and support pin 16 fixed thereto, but the other parts are of the above-mentioned type. It moves back and forth by the operation of the closing/opening cylinder and the ejector cylinder. In other words, the spacer block 7, the receiver is the plate 6
Since the mold plate 5 is fastened to the movable mounting plate 8 by bolts (not shown) or the like, it moves integrally with the mounting plate 8 by the mold clamping/opening cylinder. Further, the template plate 4 has a return pin 22 fixed thereto by a bolt 22a that passes through the template plate 5 and the plate 6, and an ejector plate 9.10 attached to the tip thereof and the plate 6. Since a spring 23 is interposed between them and biased backward, they also move together with the mounting plate 8. Support pin 16
A runner stripper plate 2 and a template 3 are slidably fitted through guide bushes 15a and 15b.
The template 3.4 is also slidably inserted into the guide pin 20 fixed to the template 5 via the guide bush 19as19b, but when the template 4 moves backward as described above, In this case, the plate 2 and the template 3 are guided by the support pin 16 or the guide pin 20 and move back and forth between the template 4 and the mounting plate 1. Moreover, the tension link 14 is
Attached to the template 5, the template 3 and the plate 2
When the mounting plate 8 (template plate 5) moves backward by a certain amount, the plate 2 is moved backward. However, the amount of rearward movement of the plate 2 is limited to the distance until the head of the bra bolt 21 that is screwed onto the plate 2 and passes through the mounting plate 1 comes into contact with the counterbore surface of the mounting plate 1. .

Figure 1 shows a state in which the mold clamping/mold opening cylinder is extended to close all mold plates and wait for the injection device to inject the resin. Then, the resin fills the tip hole of the sprue bushing 18,
It passes through the runner part a surrounded by the bushing 18 and the front recess of the insert U, and the gate b of the insert 11, and is injected into the molding space C surrounded by the cavity lla of the insert 11 and the core 13b of the insert 13. . A temperature control (cooling) pipe (not shown) is formed in the template 3.4.5, and a flow regulating fluid supplied from the outside is circulated within the pipe.
The injected resin loses its heat to the temperature regulating fluid through the inserts 11, 12, 13 and the mold plate 3, 4, 5, is cooled, and eventually solidifies.

The cooled and solidified molded product is taken out in the following manner as the mold clamping/mold opening cylinder and the ejector cylinder operate as described above. First, the mold clamping/mold opening cylinder contracts and the mounting plate 8 and the member that engages with it move rearward, so that l) the mold plate 3 (and the insert 11 fitted thereto) is moved between the plate 2 and the mold plate 3; By separating from the sprue bushing 18 and moving backward, the resin of the gate b is cut off at the minimum cross-sectional area at its tip, and 2) the mold plate 4 (insert 12) and the template 3 (insert 11) are separated. The gap opens and the molded product in the space C is extracted (the molded product shrinks and clings to the core 13b of the insert 13 and is extracted), and 3) the runner stripper plate 2 is separated from the mounting plate 1. Then, the inner edge portion 2a moves to the protruding end of the spruce S18, thereby brushing off the resin from the tip hole of the bushing 18 to the runner portion a and gate b. After this, the rod of the ejector cylinder is extended to push the ejector plates 9 and 10 forward, and the template 4 (insert 12) is separated from the template 5 (insert 13) against the biasing force of the subring 23. If this happens, the molded product that was attached to the core 13b will be machined inside and
Stripped off by Chisel Moon 2a.

Hereinafter, in the mold Δ having the overall configuration as shown in FIG. 3, the inserts 11.12, !3 are fitted with the upper seams of the mold plate 3.4.51J (in accordance with the present invention).

That is, for example, in the template 5, as shown in FIG. An annular closed space 51) having an axial length in the thickness direction, and a fluid supply channel 2 which is opened on the side of the mold plate 5 through a continuous flow, and an rfj space 5bJ from the supply channel 5C, l: By filling fluid (5tS of grease in the figure) and pressurizing it, insert
7 were holding and serving 13 nests. ! 21 space 5b, the inner wall of the receiving hole 5a bulges inward and tightens the insert 13, so that the insert 13 is reliably held.

In this embodiment, instead of connecting a fluid supply pipe to the outside, an enlarged part 5d including a screw part E is formed at the end of the supply passage 5c of the mold plate 5, and a cylinder is connected here. 55, a piston 53, a support bolt 52, and a push rod 51.

The cylinder 55 is screwed into the pipe taper (PT) thread part 1, -
Expand the diameter ff5dl; - Insert the filler 11 and grease 56 into the closed space 5b and supply path 5c; 7, and then attach the O-ring 54. Place the piston 51 inside the cylinder 55 (
- When pushed in, the pressure of grease: 5G in the closed space 5b increases.

Support!・The bolt 5z is fixed to the enlarged diameter part 5d with the outer screw, and is pushed into the inner screw (-); -g bolt 51J'
Since they are screwed together, by turning the groove at the rear end with a screwdriver etc., the push bolt 51 is screwed forward (j2), the piston 53 is pushed into the cylinder 55, and the grease 56 is pressurized (6). 'Ruko), sacrilege.

In addition, in order to regulate the position around the axis when inserting the insert 13 into the accommodation hole 5a, as shown in FIG.
A plane part e is formed on the outer circumferential surface of the housing hole 5a and a part of the inner wall surface of the housing hole 5a (7) so that they fit into each other.

In the following, only the template 5 is shown based on FIGS. I'm wearing it. Further, it is desirable to use O-ring 54 and grease 56 with high heat resistance in consideration of temperature rise during injection molding.

In this example, in the template 5 made of tool steel and having a thickness H = 3 ngm, the outer diameter c3 (=
4f) sep), the inner diameter D of the accommodation hole 5a, the accommodation hole 5
The wall thickness between a and the closed space 5b and the wall thickness at both ends of the closed space 5b in the axial direction are D = d + 0.0211 m. Oss,
It was set as h=2.0a+s. D −d = 0.02 m between the accommodation hole 5a and the JJ part 13a of the insert 13
Since there is a gap 5, the insert 13 is normally placed in the accommodation hole 5a.
Although it is easily inserted in a warm-fit state, the grease 5G in the closed space 5b is added.

When pressed, the inner wall of the receiving hole 5a elastically deforms inward and swells, thereby tightening and holding the insert 13. Although a pressure of up to approximately 1000 kg/am'' is easily generated by the fluid pressurizing means described above, the force with which the accommodation hole 5a clamps the insert 13 reaches several tons. Accommodation hole 5a
500 m/am' in the closed space 513 without inserting it into the
It was also found that when a pressure of

Pushing the fluid pressurizing means (- Turning the bolt 51 in the opposite direction to move the piston 53 backward and reducing the pressure in the closed space 5b,
The accommodation hole 5a has the original inner diameter D (= d + 0.02 sam
), the insert 13 can be easily removed from the receiving hole 5a. In this example, the nested IL 12 and others are similarly typed @
3.4, and the outer diameter of the insert 11.12 is the same d as that of the insert 13, and the inner diameter of the receiving hole of the template 3.4 is also the same D as that of the template 5, so that the insert 11.12 is inserted into the template 3.4. Because of this, each template 3.
4.5 from the mold A, all inserts 11, 12, and 13 can be removed by performing the above depressurization operation with the mold clamping/opening cylinder retracted and the mounting plate 8 moved rearward. It can be taken out. If you prepare various inserts with the same outer diameter according to each type of molded product, it is easy to insert another insert in the above condition, so replacing the inserts is smooth and quick. It will be held on.

By the way, such a template 3.4.5 can be manufactured as follows, for example, based on a normal template material (a general-purpose material for manufacturing general templates that do not use inserts). can. 3(a) to (d) show the manufacturing process using the template 5 as an example. First, from one side of the template material 5I, an annular shape having an inner diameter larger than the outer diameter of the insert by a predetermined dimension is formed. A groove 5b' is formed by cutting (FIG. 5(a)). next,
There is an enlarged diameter portion 5d between the outer surface of the material 5■ and the groove 5b'.
In order to drill a fluid supply path 5c containing
- The entire circumference of the open end of the groove 5b' on one side of the groove 5b' is filled by welding to form a closed space 5b (FIG. 3(C)). Finally, the template 5 is completed by heat treating the material 51I, drilling the accommodation hole 5a, and finishing grinding (FIG. 5(d)).

In the above, the mold A of the three-plate stripper plate ejection method has been described.
), (b) can also be applied to other types of molds. Figure (a) is called the 3-plate pin ejection method, and the stripper plate of mold A (i.e., the insert 1
Instead of the template 4) fitted with 2, insert the insert 12°-13°
The molded product is ejected from the mold by protruding the ejector turbine 24°, which can slide through the ejector plate 9° and move lOo, as shown in Figure (b).
This is a two-plate pin ejecting method, and there is one less template than the one shown in Figure (a). Such a mold also has a structure similar to that of the template 5 described above, so that the template can be adjusted at 3°.
, 4°, 5°, 3″ and 5″ respectively, nested 11
', 12°, 13°, u''.

and 12" and 13" can be fitted, and similarly, the ejector turbine 24°,
It is also possible to fit end plates 25° and 25° of 24@, respectively.

As mentioned above, FIG. 5(a) is a schematic view of the template 5 and the insert 13 taken along the line ■-■ in FIG.
) shows an example in which four insert taps are fitted into the mold plate 5p in order to obtain a large number of molded products (four in the figure) by - times of resin injection.

In this example, an enlarged diameter portion 5d is provided with a fluid pressurizing means for four accommodation holes 5ap and a closed space 5bp surrounding the sides thereof.
p is formed in two places, and the fluid supply path 5 is formed from each enlarged diameter portion 5dp.
cp is branched to communicate with the closed space sbp. Depending on how the fluid supply path 5cp is set up, the enlarged diameter portion 5dp may be
Therefore, the fluid pressurizing means can also be located at one location. Further, when a part of the enlarged diameter portion 5dp directly communicates with the closed space 5bp, it is not necessary to form the fluid supply path 5cp between and (.

FIG. 5(c) is a schematic diagram of the template 5q when the outer shape of the insert 13Q is rectangular. The closed space 5bq may surround the entire lateral side of the accommodation hole 5aq, but the figure shows an example in which it is formed only near the sides of two opposing sides of the accommodation hole 5aq. Similarly to the example shown in FIG. 2B, the fluid supply passages 5cq are branched from the enlarged diameter portions 5dq at i locations and communicated with the closed spaces 5bq at two locations. In this case as well, if the fluid pressure in the closed space SbQ is increased by the fluid pressurizing means as described above, the two sides of the accommodation hole 5aq along the closed space 5bq will bulge inward, and the inserted insert 13Q will be pushed out. Tighten and hold.

(Effects of the Invention) The injection mold of the present invention provides the following effects.

Since it is possible to share a template and manufacture only the inserts according to the type of molded product, it is advantageous in terms of mold manufacturing costs and manufacturing time compared to the case where a mold type is manufactured for each type of product. It is.

2) For example, inserts can be quickly and easily replaced while the templates remain assembled, so mold setups can be quickly changed for each type of molded product. Therefore, by taking advantage of the above-mentioned advantages, it is possible to efficiently produce a wide variety of molded products.

3) In order to reproduce the same product type, it is only necessary to store and use the insert, which is a replacement part, so mold management can be streamlined in terms of storage space and handling.

4) The template has a simple structure that can be manufactured from general-purpose materials and does not have parts that are prone to failure, so the manufacturing cost is low and the maintenance burden is low.

5) Especially if a fluid pressurizing means is provided as in claim 2,
There is no need to connect a special high-pressure fluid supply external to the mold, making the mold simpler and easier to handle.

[Brief explanation of the drawing]

Figures 1 to 5 are drawings relating to embodiments of the present invention, in which Figure 1 is a partially cutaway plan view showing the entire injection mold; Figure 2 (4) is a cross-sectional view of the clay template and insert, Figures 3 (a) to (I) are cross-sectional views showing the manufacturing process of the template, Figures 4 (aB; and (b) are the template and 5(a) is a cross-sectional view of the main parts of a mold in which the insert is assembled in a different manner from that shown in FIG. 1, and FIG. (1)) and (e) are different from the nesting method 1.
:, is a plan view of the template fitted by hand. Moreover, FIG. 6 is a sectional view of a template to which a nest is attached according to the prior art. 3, 4, 5.3', 4', 5', 3", 5"
, 5[), 5q, 105...template, 5a, 5ap,
5aq-accommodation hole, 5b, 5hp, 5bq=-closed space, 5e, 5cp, 5eQ-fluid supply path, 11, 12
, 13, 11'42'. 13°, 11', 12''.13'', 13p, 13q
, t13...Insert, 51...Push bolt 1.53
...Piston, 56...Grease, A...Mold.

Claims (1)

[Claims] 1. In an injection mold that constitutes the main part by combining a template with a insert attached thereto, the template includes an accommodation hole into which the insert can be loosely fitted as an attachment part for the insert. At the same time, a closed space for fluid sealing is formed near the side of the accommodation hole, and a fluid supply path that communicates with the closed space and opens on the outer surface of the mold plate is formed so that the A mold for injection molding, wherein a fluid is filled in a closed space, an insert is inserted into the accommodation hole, and the insert is held by pressurizing the fluid. 2. A fluid pressurizing means having a screw member and a sliding piston member is provided near the open end of the fluid supply path, and fluid is sealed in the closed space and the fluid supply path. Mold for injection molding.