JPH0515534B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention particularly relates to a molding die suitable for use in molding synthetic resin molded products having concave portions on both sides.

(Prior Art) Generally, a molded product 100 used for an electrical wiring connector or the like shown in FIG. 5 is formed with an open cylindrical portion having open end faces at each of its opposite ends.

In addition, in FIG. 5, each of the open cylindrical portions is shown as a recess 101, 102.

When molding such a molded product 100 by injection molding, each of the recesses 101 and 102 shown in FIG. 5 is formed by a fixed mold having a core portion and a movable mold.

By the way, in the case of injection molding, the mold is usually opened while the molded product is attached to the movable mold side, and the molded product is ejected from the mold by an ejector pin provided in the movable mold.

However, when the mold shown in FIG. 5 is injection molded using a mold in which a core part is provided in each of the movable mold and the fixed mold, the resulting molded product 100 adheres to the fixed mold side and is opened. There's a problem. In such a case, it is necessary to stop the injection molding and remove the molded product manually.

This phenomenon occurs because when the molten resin filled in the cavity is cooled, the concave portions 101 and 102 of the molded product firmly adhere to each core portion due to contraction of the resin.

Conventionally, in order to solve this problem, a method was used in which undercuts (uneven parts) were added to the movable mold to forcefully release the molded product from the fixed mold when the mold was opened, or As in the method for molding a low-absorption synthetic resin material disclosed in Publication No. 47651, an ejector pin that is biased forward by a spring is provided in a fixed mold, and the molded product is pressed by the ejector pin when the mold is opened. A method was used to do so.

(Problem to be solved by the invention) However, in all conventional methods including the above-mentioned method, the molded product is not easily removed when the mold is opened by making the mold release resistance on the movable mold side larger than that on the fixed mold side. Since it is attached to the movable mold side, there are the following problems.

In other words, as mentioned above, in a molded product that has recesses on both the movable mold side and the fixed mold side, if overpacking occurs on the fixed mold side, the mold release resistance on the fixed mold side will be lower than that of the movable mold side. larger than the side,
The molded product cannot be removed using the above-mentioned means for creating an undercut. This also applies to methods using ejector pins, and if the mold release resistance on the fixed side becomes greater than the pin pressure, the molded product cannot be taken out.

Furthermore, when using an ejector pin, there is a risk that it may leave marks on the molded product, deteriorating the molding quality and marketability, which is undesirable. In the case of the nested type, the cost increases significantly and replacement work becomes difficult, so in reality, the method using the ejector pin is not used.

Therefore, the present invention provides a molding die that eliminates the above problems.

(Means for Solving the Problems) The present invention has been made in order to solve the above problems.

Its characteristics are as shown in Fig. 1, the fixed platen 34
An open cylindrical part with an open end face (in FIG. 1, the open cylindrical part formed by the fixed mold 2 is In a molding die 1 for molding a molded product W having recesses (shown as recesses 4) at both ends, a fixed side base 25 is fixed on a fixed platen 34.
A fixed core part having one end fixed at the top and a tip end facing the cavity 7 formed by the fixed mold 2 and the movable mold 3 at the other end to form one open cylindrical part of the molded product W. 5, one end of which is fixed to the movable mold 3, and the tip end of the other end is fixed to the cavity 7.
A movable core part 67 facing inward and forming the other open cylindrical part of the molded product W is axially fitted to the fixed mold core part 5 so as to slide within a certain stroke range, and the fixed mold 2 and When the movable mold 3 is clamped,
When the fixed mold movable part 54 is provided with a recess 17 that forms one side of the cavity together with the fixed mold core part 5, and the fixed mold 2 and the movable mold 3 are opened, the recess 17 of the fixed mold movable part 54 is opened. The fixed mold movable part 54 is attached to the movable mold 3 direction so that the side end of one open cylindrical part of the molded product W is pressed on the bottom side and the one open cylindrical part is released from the fixed mold core part 5. A biasing member 57 that applies force, a molded product W attached to a movable core portion 64 of the movable mold 3, etc., and a protruding pin 7 that protrudes from the movable mold 3.
7.

(effect) Next, the operation of the present invention will be explained.

First, as shown in FIG. 2, when the molding die 1 is in the clamping state, the fixed movable part 9 is at the most retracted position above the fixed core part 5 by the movable die 3, and in this state, the fixed core A regular cavity 7 is formed by the part 5 and the fixed movable part 9. On the other hand, when the mold is opened, the movable mold 3 separates from the fixed mold 2 as shown in FIG. Move within a certain stroke range. In this case, since the fixed core part 5 is fixed, the fixed movable part 9 pushes out the molded product W from the fixed core part 5,
The recessed part 4 of the molded product W is peeled off from the fixed core part 5.

(Example) Below, preferred examples according to the present invention will be described in detail based on the drawings.

Figures 1 and 2 show longitudinal sectional side views of the telescoping mold according to the present invention, with Figure 1 in the mold open state, Figure 2 in the clamped state, and Figure 3 in the same mold. FIG. 4 is a vertical side view of the nested mold in the same molding die.

First, the configuration of the molding die 1 will be explained.

The molding die 1 consists of a main die 20 and a nesting die 50 that is replaceably attached inside the main die 20.

The main mold 20 is a fixed main mold 21 as shown in FIG.
and a movable main mold 22.

The fixed main mold 21 is further integrated by overlapping a fixed main mold front part 23 and a fixed main mold rear part 24, and can slide forward or backward on a guide pin 26 fixed to a fixed main mold base 25. Install. Further, a movement limiting bolt 27 is screwed onto the fixed main mold rear part 21, and this bolt 27 restricts the movement of the fixed main mold 21 on the guide pin 26 within a certain stroke range by engaging with the base 25. The front and rear portions 23 and 24 of the fixed main mold have fixed nesting type mounting holes 28 and 29 formed through the inside thereof, and the front portion of the fixed main mold 23 has a nesting type mounting hole 28 and 29 that protrudes into the mounting hole 28. Equipped with a stopper pin 30 for fixing the
This pin 30 is elastically supported by a spring 31. In addition, reference numeral 32 is a fixing bolt that integrates the front part 23 and rear part 24 of the fixed main mold, 33 is a guide bush inserted between the guide pin 26 and the front part 23 of the fixed main mold, and 34 is a fixing bolt that fixes the main mold base 25. board (see Figure 1).

On the other hand, the movable main mold 22 is formed by overlapping a movable main mold front part 35 and a movable main mold rear part 36, which are connected to a movable platen 37.
(See Figure 1). The front part 35 and the rear part 36 have movable telescoping type mounting holes 38 and 39 penetrating inside, and the front part 35 has mounting holes 38 and 39.
A stopper pin 40 is provided to protrude into the inside of the mold and fix the nesting mold, and this pin 40 is attached to a spring 41.
It is elastically supported by. In addition, the code|symbol 42 is the fixing bolt for integrating the said front part 35 and rear part 36, and 43
44 is a guide bush into which the guide pin 26 is inserted and aligned, and 44 is an insertion hole for a protruding rod.

Next, the nested mold 50 will be explained. Nested type 5
0 consists of a fixed nesting die 51 and a movable nesting die 52, as shown in FIG.

The fixed insert 51 further includes a core portion 53 and a movable portion as a fixed movable portion 54 (hereinafter sometimes referred to as the movable portion 54). The core portion 53 includes a fixed core body 55 (hereinafter sometimes referred to as the core body 55) formed into an axial shape.
The front end portion including the front end 55a is the fixed core portion 5 that protrudes into the cavity 7 (FIG. 2) formed by clamping the fixed insert mold 51 and the movable insert mold 52, and the core body 55 The rear end 55b is the core support portion 5
Combine with 6. On the other hand, the movable part 54 is axially fitted to the core body 55 so as to slide, and has a recessed portion on its front surface (parting surface) that forms half of the cavity 7 together with the fixed core part 5 and the movable insert mold 52. 17 are provided. In addition, the core support portion 56
A spring 57 is compressed between the core support portion 56 and the movable portion 54, and the two are biased in the direction of repelling each other.On the other hand, a movement limiting bolt 58 disposed between the core support portion 56 and the movable portion 54 prevents the relative movement of the two. Movement is limited to a certain stroke range. This stroke range is almost the same as the relative stroke range of the fixed main mold 21 and the fixed main mold base 25 described above. The movable part 54 also has a guide pin 59 that protrudes forward and is inserted into the movable nesting mold 52 for positioning.
At the same time, a stopper recess 60 that engages with the stopper pin 30 of the fixed main mold 21 is formed on the upper surface.

The movable part 54 consists of a movable part front part 61 and a movable part rear part 62, which are integrated by a fixing bolt 63.
The guide pin 59 is prevented from coming off by the rear part 62. Furthermore, the core support part front part 64 and the core support part rear part 65 are integrated by a fixing bolt 66, and the core main body 55 is prevented from coming off by the rear part 65.

On the other hand, a cavity 7 is provided on the front side (parting surface) of the movable insert mold 52 together with the fixed insert mold 51.
A recess 27 forming half of the recess 27 is provided.
A movable core portion 67 (hereinafter sometimes referred to as core portion 67) is provided inside. Further, the lower part has a guide hole 68 into which the guide pin 59 is inserted,
A stopper recess 69 that engages with the stopper pin 40 of the movable main mold 22 is formed on the upper surface. In addition, the movable nesting mold 52 is integrated with a fixing bolt 72 by overlapping a movable nesting mold front part 70 and a movable nesting mold rear part 71. A protruding plate holding plate 73 is arranged at a predetermined interval behind the movable nesting mold 52 and is connected with a fixing pin 74. A protruding plate 75 is slidably fitted into the fixing pin 74, and a spring 76 is compressed between the protruding plate 75 and the movable insert mold 52. on the other hand,
A protruding pin 77 is provided on the front surface of the protruding plate 75, and this protruding pin 77 passes through the movable nesting die 52 and faces into the cavity 7. Note that the reference numeral 78 is an insertion hole for a protruding rod 79 (see FIG. 1).

As shown in FIG.
are inserted into the mounting holes 38 and 39, respectively. At this time, the stopper pins 30 and 40 and the stopper recesses 60 and 69 are engaged with each other and aligned.

Next, referring to FIGS. 1 and 2, the molding die 1
The operation will be explained.

First, the clamped molding die 1 is in the state shown in FIG. 2, and the movable main die 22 (movable nesting die 52) and the fixed main die 21 (fixed nesting die 51) come into contact to form the cavity 7. be done. At this time, the fixed main mold 21 is pushed by the movable main mold 22 and retreats on the guide pin 26, and the fixed main mold rear part 24 comes into contact with the fixed main mold base 25. Further, in the fixed nesting mold 51, the movable part 54 retreats on the core part 53 and compresses the spring 57 to come into contact with the core support part 56.
Furthermore, the core support portion 56 is connected to the fixed side main mold base 25.
comes into contact with. In this case, each guide pin 26, 59
are inserted into the guide bush 43 and guide hole 68 and positioned.

In this way, the clamped molding die 1 is processed in a known injection molding process, that is, the nozzle on the molding machine side and the fixed nesting mold 51 are received, and the resin material injected from the nozzle is placed in the nesting mold 50. The cavity 7 is filled through a sprue, runner, and gate (not shown). After a predetermined cooling time, the nozzle is retracted and the molding die 1 is opened.

When the mold is opened from the state shown in FIG.
Due to the repulsive force of the ball, it moves (advances) while remaining in close contact with Itsuki. Note that at this time, the core support portion 56 is attached to the fixed side main mold base 2 due to the action of the spring 57.
In this state, the movable part 54 slides forward on the core body 55. The movement of the movable portion 54 presses the end surface 8 of the molded product W, thereby causing the recessed portion 4 of the molded product W to be separated from the fixed core portion 5. Therefore, the molded product W is taken out while being adsorbed to the movable nesting mold 52 side.

Further, as the mold opening progresses, the mold opening is finally completed as shown in FIG. By the action of the movement limiting bolts 27 and 58, the fixed main mold 21 and the movable part 54 move forward within a preset stroke range with respect to the fixed main mold base 25 and then stop. In this case, the core portion 53, that is, the core support portion 56, contacts the stationary main mold base 25 and remains fixed.

Then, by moving the ejecting rod 79 forward, the ejecting plate 75 and ejecting pin 77 are ejected forward, and the molded product W can be pushed out of the recess 27 and released from the mold.

In the above embodiment, if the fixed main mold 21 is fixed to the fixed main mold base 25 with bolts or the like, the movable part 54 is also completely fixed to the core part 53 and can be used as a normal telescoping mold. I can do it.

Although the embodiments have been described in detail above, the present invention is not limited to these embodiments. For example, although the present invention has been applied to a telescoping mold, it can of course also be applied to a regular single fixed mold or a movable mold. Further, although the spring 57 is used as a biasing means, any other biasing means such as an air cylinder, a hydraulic cylinder, an elastic member, etc. can be used. Other details such as shape, structure, arrangement, quantity, etc. may be changed as desired without departing from the spirit of the present invention.

(Effects of the Invention) As described above, the molding die according to the present invention includes a fixed mold and a movable mold, and has at least a concave portion in the portion formed by the fixed mold.
The fixed mold has a fixed core part whose rear end is fixed to the fixed base and whose front end faces into the cavity to form the recessed part, and which is shaft-fitted to slide within a certain stroke range with respect to the core part. At the same time, since it is provided with a fixed movable part that shapes the remaining part other than the recessed part which is urged in the forward direction, the following remarkable effects are obtained.

When the mold is opened, the movable part of the fixed mold moves against the fixed mold core that forms the recess of the molded product, and by applying a uniform pressing force around the molded product, that is, to the entire molded product, reliably resists mold release. The molded product can be removed from the fixed mold by reducing the

Since the fixed core part and the fixed movable part move relative to each other, there is no need for a separate ejector pin, etc., and it is possible to improve the quality and marketability of molded products without leaving unnecessary marks on the molded products. can.

In particular, when the preferred embodiment is applied to a nested mold, the structure can be simplified by reducing the number of component parts, resulting in lower costs and easier replacement work, which is required for the nested mold. It can fully meet the demand for lower prices.

[Brief explanation of the drawing]

1 and 2 show longitudinal sectional side views of the nesting type molding die according to the present invention, and FIG. 1 shows the mold in the open state,
Figure 2 shows the mold clamped state, Figure 3 is a vertical cross-sectional side view of the main mold in the same mold, Figure 4 is a vertical cross-sectional side view of the nested mold in the same mold, and Figure 5 shows the same mold. FIG. 3 is a longitudinal cross-sectional side view of a molded product suitable for molding. In the drawings, 1...molding mold, 2...fixed mold, 3
...Movable mold, 4...Concavity of molded product W, 5...Fixed core part, 7...Cavity, 25...Fixed side base, 34...Fixed plate, 37...Movable plate, 54...
...fixed movable part, 57...biasing member.

Claims (1)

[Scope of Claims] 1. A molding die for forming a molded product having an open cylindrical part with an open end face at both ends, comprising a fixed mold mounted on a fixed plate and a movable mold mounted on a movable plate. One open cylinder of the molded product is fixed at one end on a fixed side base fixed on the fixed plate, and at the other end, the tip part faces into the cavity formed by the fixed mold and the movable mold. a fixed core part forming a shaped part; a movable core part having one end fixed to the movable mold and a tip end facing into the cavity at the other end to form the other open cylindrical part of the molded product; A recessed portion is provided which is axially fitted so as to slide along the fixed mold core part within a certain stroke range, and forms one side of the cavity together with the fixed mold core part when the fixed mold and the movable mold are clamped. When the fixed mold movable part and the fixed mold and the movable mold are opened, the bottom surface side of the concave part of the fixed mold movable part presses one open cylindrical part side end of the formed product toward the movable mold, a biasing member that biases the fixed movable part in the direction of the movable mold so as to release the one open cylindrical part from the fixed core part; A molding die characterized by comprising a protruding pin that protrudes from the mold. 2. The molding die according to claim 1, wherein the molding die is a nested mold that is replaceably attached to the main mold. 3 Claims in which the nested mold is composed of a fixed nested mold and a movable nested mold, and when the mold is opened, the fixed main mold moves together with the movable part of the fixed nested mold used as a movable part of the fixed mold. The molding die according to item 1 or 2.