JP3855767B2 - Mold equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold apparatus in which a cavity part that forms an outer shape part of a molded product, a core pin part that forms a hollow part in the molded product, and an ejector pin that detaches the molded product from a mold.
[0002]
[Prior art]
Most of the end portions of the opening of the writing instrument cap and the container lid are formed perpendicular to the axis. An example is Japanese Patent No. 3034448. Such products are molded by injection molding in order to produce them in large quantities and at low cost. Here, the mold apparatus used for the injection molding will be described. The mold includes a cavity part that forms the outer shape part of the molded product, a core pin part that forms a hollow part in the molded product, and a molded product that is a mold. And at least an ejector pin that is separated from the ejector pin. Specifically, the lower end portion of the cavity is a circumferential portion perpendicular to the axis, and the top portion of the ejector pin for detaching the molded product from the mold (core pin) is located in this portion. ing. Of course, the top of the ejector pin is a circumferential surface portion perpendicular to the axis of the ejector pin.
However, in recent years, in order to increase the added value of products, from the viewpoint of design, products in which the end portion of the cap opening portion is inclined with respect to the axis have come into circulation. For example, a cap 100 as shown in FIG. An end portion of the cap body 101 which is a bottomed cylindrical portion is an inclined opening 102. And the top part 104 of the ejector pin 103 of the metal mold | die apparatus which shape | molds the product is formed in the state inclined according to the edge part opening part 102 of the molded article.
[0003]
[Problems to be solved by the invention]
However, in the above prior art, since the contact portion (opening 102 and top 104 of the ejector pin) between the molded product and the ejector pin is inclined, the molded product is pushed out by the ejector pin 103. In the middle of the protrusion, the pushing force to the molded product 101 was dispersed. That is, the force A is pushed out straight with respect to the axis of the ejector pin 103 and the force B is rotated with respect to the axis. As a result, a biased force is applied to the cap 100, causing cracks, whitening (becomes white due to plastic deformation), and scratches. Further, since the rotational action also affects the core pin 105 disposed inside the ejector pin 103, a sliding resistance is generated between the core pin 105 and the ejector pin 103, and the problem that the smooth operation does not occur. Has also occurred.
[0004]
[Means for Solving the Problems]
Therefore, in the present invention, a cavity for forming the outer shape portion of the molded product, a core pin for forming a hollow portion in the molded product, and an ejector pin for detaching the molded product from the mold are arranged on the outer periphery of the core pin so as to be movable back and forth. A mold device, wherein the front end portion of the core pin is positioned in the cavity, while the rear end portion is fixed to the movable side mold plate group, and the front end portion of the ejector pin is an intermediate portion of the core pin, In addition, the first aspect of the present invention is that a guide wall that is disposed at the rear part of the cavity and covers at least one part of the molded product molded by the cavity from the outside is formed at the tip of the ejector pin. a core pin for forming a hollow portion in the cavity and the molded article to form the outer portion, the ejector pin back and forth to detach the molded product from the mold the outer periphery of the core pin A mold device arranged in a possible manner, wherein the front end portion of the core pin is positioned in the cavity, while the rear end portion is fixed to the movable side mold plate group, and the front end portion of the ejector pin is placed in the middle portion of the core pin. The second gist is that the inner wall surface is formed at the rear part of the cavity and has the same shape as the outer shape of the end part of the molded product formed by the cavity at the tip inner shape part of the ejector pin. And
[0005]
[Action]
Although there is a dispersion of force to the molded product due to the ejecting force of the ejector pin, since the rotational action of the molded product is prevented, the molded product is extruded straight with respect to the axial direction of the ejector pin.
[0006]
【Example】
One example will be described with reference to FIGS. The mold apparatus M includes a fixed mold group 1 and a movable mold group 2 and has a general split mold structure. The movable side mold group 2 is provided with a cavity block 4 in which a cavity 3 forming the outer shape of a molded product is formed. The cavity block 4 is a molded product (cap 100 in this example). The cavity block 4a for forming the main body 101 and the cavity block 4b for forming the vicinity of the inclined opening 102 are constituted. Each of these cavities is divided into two parts, which are in close contact with each other when the mold M is closed, and are separated from each other when the mold M is expanded. A core pin 5 that forms a hollow portion in the cap 100 is slidably disposed inside the cavity 4, but the rear end portion of the core pin is fixed to the movable-side template group 2. .
In addition, an ejector pin 6 for detaching the molded product (cap 100) from the mold M (core pin 5) is disposed on the outer periphery of the core pin 5 at the rear portion of the cavity 3 so as to be movable back and forth. However, the rear end of the ejector pin 6 is fixed to the ejector plate 7. On the other hand, the tip end portion of the ejector pin 6 is formed with an inclined end portion 8 which is inclined with respect to the axial direction of the ejector pin 6 and has substantially the same inclination angle as the inclination of the opening portion 102 of the cap 100. However, the portion does not have to be inclined. Further, a guide wall 9 into which the outer peripheral portion of the opening 102 of the cap 100 is fitted is formed inside the inclined end portion 8, and the opening 102 of the cap 100 is formed below the guide wall 9. An inner surface inclined portion 9a having the same inclination angle as the above-described inclination and in a planar contact with the opening 102 is formed (particularly, see FIG. 2). The inner surface inclined portion 9 a comes into contact with the opening 102 and causes the cap 100 to be detached from the core pin 5.
[0007]
Here, in this example, the guide wall 9 is engraved so that the entire peripheral edge (opening 102) of the cap 100 to be molded is fitted, but the guide wall may be partially formed. Even if it says that it engraves, it may be press-fitted a little, or a clearance gap may be formed a little. In addition, when forming a guide wall partially, it is preferable to form in the position on the opposite side to the rotation direction of a molded article at least. That is, the rotation of the molded product is prevented by forming a guide wall and fitting and locking the end of the molded product to the guide wall.
In addition, a clip 106 is formed integrally with the main body 101 of the cap 100 of this example, and a ball 107 is also formed on one side of the clip 106. And the ball part 107 is shape | molded inside the inner surface of the main-body part 101. FIG. Therefore, a concave portion 10 is formed in the middle portion of the core pin 5 so that a cavity portion that forms the ball portion 107 is positioned.
Reference numeral 10 denotes a runner groove through which resin flows, and a sprue hole 12 through which the resin flows into the cavity 3 is connected and formed in a direction perpendicular to the runner groove 11.
[0008]
Next, the operation will be described. The example shown in FIG. 1 is a state where the mold M is closed, and the resin flows into the cavity 3 in this state. When this resin is filled in the cavity 3 and cooled, the expanding operation of the mold M is started. The cavity 3 in close contact is also expanded by the expansion operation of the mold M, and the molded product (cap 100) fixed to the core pin 5 is exposed from the mold M. Here, when the mold M further expands, the ejector plate 7 relatively moves in conjunction with the expanding operation, and as a result, the ejector pin 6 also moves forward. As the ejector pin 6 advances, the guide wall 9 formed at the tip of the ejector pin 6 is fitted to the end of the cap 100 and starts to push the cap 100 away from the core pin 5. (See FIG. 3). At this time, the inclined opening portion 102 of the cap 100 and the inner surface inclined portion 9a of the ejector pin 6 come into contact with each other, and the ejector pin 6 presses the cap 100 and starts to impart a rotating action to the cap 100. Since the end portion of the mold 106 is surrounded by the guide wall 9, the rotation of the cap 100 is prevented. Further, when the expanding operation of the mold M is increased, the ball portion 107 of the clip 106 covers the outer diameter portion of the core pin 5. The cap 100 is elastically bent so as to get over, and the counter action also imparts a rotational action to the cap 100 at this time. However, even in this state, since the opening 102 is fitted in the guide groove 9, rotation by the above-described action is prevented (see FIG. 4).
When the mold M is further expanded, the cap 100 is completely pushed out of the core pin and falls by its own weight (see FIG. 5).
[0009]
A second example will be described with reference to FIG. In the previous example, the opening was inclined and the ball part of the clip reached the inner diameter part of the cap, that is, when the molded product was released from the core pin, it was relatively easy to rotate. As shown in the second example, the present invention may be applied to a molded article (cap) 200 that is used for a container such as a lipstick, an eyeliner, or a mascara, in which a clip is not formed. Of course, an inclined portion 201 is formed at the end of these molded products, but this inclined portion may be a linear inclined portion or a curved wave-like inclined portion. .
[0010]
【The invention's effect】
The present invention relates to a metal mold in which a cavity for forming an outer shape portion of a molded product, a core pin for forming a hollow portion in the molded product, and an ejector pin for detaching the molded product from a mold are arranged on the outer periphery of the core pin. A mold device, wherein the front end portion of the core pin is positioned in the cavity, while the rear end portion is fixed to the movable side mold plate group, and the front end portion of the ejector pin is an intermediate portion of the core pin, and The first aspect is that a guide wall that is disposed at the rear part of the cavity and covers at least one part of the molded product formed by the cavity from the outside is formed at the tip of the ejector pin. a core pin for forming a hollow portion in the cavity and the molded article to form a said molded article ejector pin to disengage from the mold back and forth rotatably to the outer circumference of the core pin The mold device is disposed, the front end portion of the core pin is positioned in the cavity, the rear end portion is fixed to the movable side mold plate group, and the tip portion of the ejector pin is an intermediate portion of the core pin. In addition, the second gist is that the inner wall surface having the same shape as the outer shape of the end portion of the molded product formed by the cavity is formed in the tip inner shape portion of the ejector pin while being arranged at the rear portion of the cavity. Therefore, it is possible to obtain a good molded product that does not cause cracking or whitening.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first example of the present invention.
FIG. 2 is a perspective view showing an end portion of an ejector pin.
FIG. 3 is a longitudinal sectional view showing a main part of the operation.
FIG. 4 is a longitudinal sectional view of an essential part showing the operation.
FIG. 5 is a longitudinal sectional view of the main part showing the operation.
FIG. 6 is a longitudinal sectional view of an essential part showing a second example.
FIG. 7 is an external view showing a molded product.
FIG. 8 is a longitudinal sectional view of a main part showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed side template group 2 Movable side template group 3 Cavity 4 Cavity block 5 Core pin 6 Ejector pin 7 Ejector plate 8 Inclined end part 9 Guide wall 10 Recess 11 Runner groove 12 Sprue

Claims (3)

A mold apparatus in which a cavity for forming an outer shape part of a molded product, a core pin for forming a hollow part in the molded product, and an ejector pin for detaching the molded product from the mold on the outer periphery of the core pin are arranged to be movable back and forth. The front end of the core pin is positioned in the cavity, while the rear end is fixed to the movable side plate group, and the front end of the ejector pin is an intermediate part of the core pin, and the rear part of the cavity And a guide wall that covers at least one part of the molded product formed by the cavity from the outside is formed at the tip of the ejector pin. A mold apparatus in which a cavity for forming an outer shape part of a molded product, a core pin for forming a hollow part in the molded product, and an ejector pin for detaching the molded product from the mold on the outer periphery of the core pin are arranged to be movable back and forth. The front end of the core pin is positioned in the cavity, while the rear end is fixed to the movable side plate group, and the front end of the ejector pin is an intermediate part of the core pin, and the rear part of the cavity The mold apparatus is characterized in that an inner wall surface having the same shape as the outer shape of the end portion of the molded product formed by the cavity is formed in the tip inner shape portion of the ejector pin.   The end of the molded product is inclined with respect to the axis, and the front end of the ejector pin is formed to be inclined in accordance with the end of the molded product. 2. The mold apparatus according to 2.

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