JPH072352B2 - Mold for box - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for a box,
More specifically, the first resin forming the primary molding portion forming the pair of side portions of the box body, and the bottom portion of the box body which is sandwiched between the pair of side portions and traverses the bottom portion of the box body in a strip shape, and the end portions are The present invention relates to a molding die for a box in which physical properties such as a hue are different from each other with a second resin forming a secondary molding portion that constitutes a part of both side surface portions of the body.

[0002]

2. Description of the Related Art Various meter covers, cassette halves,
In various cases and the like, the box 100 shown in FIG. 7 is used. Such a box 100 has a strip-shaped central portion 120 (hereinafter, referred to as “second portion”) sandwiched between side portions 110, 110 (hereinafter, sometimes referred to as primary molding portion 110) made of a colored resin (first resin). The next molding part 120 may be referred to as a “subsequent molding part 120”, and is formed of a transparent resin (second resin) so that the scales and tapes of the meter housed in the box 100 can be visually observed from the outside. The box 100 is formed by sequentially injection-filling a first resin, which is a colored resin, and a second resin, which is a transparent resin, using a molding die proposed in Japanese Patent Laid-Open No. 50-149751. Can be obtained by In this case, first, by sliding a resin filling cavity for molding the secondary molding portion 120 (hereinafter, referred to as a secondary molding portion cavity), a resin filling cavity for molding the primary molding portion 110 (hereinafter,
The primary molding portion cavity) and the secondary molding portion cavity are separated and isolated, and the primary molding portion cavity is filled with the first resin. Next, the secondary molding part cavity is slid to a position where it is connected to the primary molding part cavity already filled with the resin, and the transparent resin is filled in the secondary molding part cavity.

[0003]

By using the molding die of the above publication, it is possible to melt-mold the box 100 made of resin having different physical properties with one molding die. However, when the primary molding part cavity is filled with the resin, it is necessary to slide the secondary molding part cavity completely, so that the molding die tends to be large. Moreover, since it is difficult to maintain the fitting accuracy of the primary molding part cavity and the secondary molding part cavity, the strip-shaped body 120 and the side part 11
A step may be easily formed between 0 and 110, and the appearance of the obtained box may be inferior. Further, the strip portion 120 and the side portion 11
Since the joining with 0 and 110 is performed only on the narrow end face, the joining strength becomes low in the case where the wall thickness is thin. Therefore, an object of the present invention is to make it possible to form a box body having a high joint strength between a belt-shaped portion and a side portion formed of resins having different physical properties and having a good appearance, and a box that can be miniaturized. An object of the present invention is to provide a molding die for a box that can mold the body.

[0004]

Means for Solving the Problems As a result of studies to achieve the above-mentioned object, the inventors of the present invention have found that a fixed-type core that forms a cavity with a recess of a movable mold that constitutes a molding die,
By dividing the core into movable cores that can move back and forth and minimizing the moving cavity, it is possible to reduce the size of the molding die and the accuracy of fitting the primary molding cavity and the secondary molding cavity as much as possible. In addition, by making the end face of the center core located at the center of the fixed split core into a stepped convex end face, it is possible to reduce the size of the molding die and the strip shape on the lower side of the side part of the obtained box. The present invention has been accomplished by finding that the resin layer forming the part is interposed, and the bonding strength between the side part and the strip part can be improved. That is, the present invention is
First forming a primary molding part constituting a pair of side parts of the box
And a second resin which is sandwiched between the pair of side portions and traverses the bottom surface portion of the box body in a band shape, and whose end portions form a secondary molding portion which constitutes a part of both side surface portions of the box body. In a molding die of a box in which physical properties such as hues are different from each other, the core portion of the fixed die forming a cavity between the concave portion of the movable die forming one side of the die and the core portion of the die opening / closing direction. Provided so as to be able to move forward and backward, the end face on the parting surface side is a fixed type center core that is a stepped convex end face, and is provided so as to move forward and backward in the mold opening and closing direction by sliding contact with the side wall face of the fixed type center core. The fixed type center core is sandwiched between the pair of fixed type side cores, and the fixed type core is fixed to the fixed type, and the fixed type center core and the fixed type side core are slidably brought into contact with each other. In the movable concave part to configure,
When the fixed center core advances, the top surface of the convex end surface of the fixed center core abuts, and in the cavity formed between the lower surface of the convex end surface and the secondary molding portion, the surface is joined. The secondary molding part formed by contacting a part of the end surface of the fixed side core to each of the flat bottom surface part forming the joint part of the primary molding part and the pair of holes formed in the recess wall surface. A movable mold core that is inserted so as to move forward and backward so that the cavity that molds the end of the movable mold core can be moved in the mold opening and closing direction, and the shape of the end face of the movable mold core that contacts the fixed mold side core is movable. A molding die for a box body, which has a shape that forms a part of the inner wall surface of the movable die recess when the die core retracts. In the present invention having such a configuration, at each end of the fixed side core and the movable side core,
When the step is formed, when the upper surface of the step abuts, a cavity for molding the end of the secondary molding portion can be accurately formed between the lower surfaces of the step. In addition, the fixed center core and the pair of fixed side cores are incorporated in the insert die, and / or the pair of movable side cores are incorporated in the insert die. It can be done easily.

[0005]

According to the present invention, since the box can be formed by making only the cavity for forming the end of the secondary molding portion movable, it is possible to compare with a mold that moves the entire cavity forming the secondary molding portion. Thus, the molding die can be downsized. Further, since the bottom surface of the movable concave portion that abuts the bottom surface of the box can be flush with the movable core when it is retracted, the appearance of the obtained box can be improved. Furthermore, since the tip surface of the fixed type fixed center core is a stepped convex end surface, a resin layer forming a band-shaped portion can be interposed on the lower side of the side portion of the box, and the side portion of the box can be The bonding area with the strip portion is increased, and the bonding strength between the two can be improved.

[0006]

The present invention will be described in more detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a state where the movable die 10 and the fixed die 20 are opened and a box 50 which is a molded product is taken out. In the figure, the movable die 10 is provided with a recess 12 that forms a cavity for molding the box 50 between the core of the stationary die 20 and one end surface that forms a part of an inner wall surface of the recess 12. Mold cores 14 and 15 are provided. The concave portion 12 is formed on the parting surface, and the other end surfaces of the movable cores 14 and 15 are formed on the inclined surface.
The slopes of the movable cores 14 and 15 are the movable cylinders 16 and
It is in contact with the slopes of pressing members 18, 18 that are provided by 16 so as to be movable in a direction perpendicular to the mold opening / closing direction.
Due to the contact between the slopes, the movable cylinder 1
The movement of the pressing members 18, 18 in the direction perpendicular to the mold opening / closing direction due to 6, 16 is converted into the movement in the mold opening / closing direction in the movable mold cores 14, 15. A perspective view of such a movable die 10 is shown in FIG. 2a. FIG. 2 a shows a movable die 10 as a nesting die, which has a recess 12
Is the bottom surface of the movable core 14, 15 and the flat surface 11
(FIG. 1). The movable die 10 shown in FIG. 2a shows the movable die 10 shown in FIG. 1 in an upward direction.

The fixed die 20 forming a pair of the movable die 10 and the forming die forms a core projecting on the parting surface and forming a cavity for molding the box 50 with the recess 12 of the movable die 10. The part is divided into a plurality of parts. FIG. 2b shows the situation in which such a core part is divided. FIG. 2b illustrates a stationary die 20 as a nesting die. The fixed center core 22 (hereinafter sometimes referred to as the center core 22) is a core that is disposed in the center of the divided core portion and that has an end face formed in a stepped convex end face. The cores adjacent to the protrusions of the core 22 are fixed type side cores 24 and 25 (hereinafter sometimes referred to as side cores 24 and 25). The center core 22 and the side cores 24 and 25 are provided so as to be movable back and forth in the mold opening and closing direction, as will be described later. On the other hand, the cores 34, 34, ... Provided at the four corners of the core part and moved forward and backward while the center core 22 and the side cores 24, 25 are in sliding contact with each other are fixed cores fixed to the fixed mold body.

At the end of the center core 22 of the split core, as shown in FIG. 1, the T-shaped end is a space 40 in the fixed mold body.
Has been inserted into. At this T-shaped end, the core cylinder 2
Center core piston 2 inserted in each of 3 and 23
Since 6 and 27 are fixed, the center core can move back and forth in the mold opening and closing direction. In addition, the side core 24,
As for the end of 25, as shown in FIG. 1, the L-shaped end is inserted into the space 40 in the fixed mold body along the T-shaped end of the center core 22. Since the side core pistons 28, 29 inserted into the center core pistons 26, 27 are fixed to the L-shaped end portions, the side cores 24, 2
Reference numeral 5 is movable in the mold opening / closing direction while being in sliding contact with the wall surface of the center core 22. In addition, the core cylinders 23, 23
The hydraulic passages 30 and 32 are provided in the center core piston 2.
6 and 27 are pushed down and the center cores 26 and 27 are
Through the small holes formed in the outer wall surface of the center core 26, 27
While entering the inside and pushing down the side core pistons 28 and 29, the hydraulic pressure supplied from the hydraulic passage 32 is changed to the center core pistons 28 and 29 and the side core pistons 28 and 2.
Push 9 at the same time.

When the movable die and the fixed die shown in FIGS. 1 and 2 are closed and hydraulic pressure is supplied from the hydraulic passage 32, the center core 22 and the side cores 24 and 25 are simultaneously pushed up,
The top surface of the convex end surface of the center core 22 is a movable concave bottom surface 1
When abutting on 1, the center core 22 stops rising. On the other hand, the side cores 24 and 25 are the center core 22.
Even if the rise of the movable mold cores is stopped, the movable cores 14 and 15 in which the pressing of the movable cylinders 16 and 16 is released by the hydraulic pressure supplied from the hydraulic passages 32 contact the part of the end faces of the pressing members 18 and 18. It rises while touching. Side cores 24, 25
Is stopped when the L-shaped end contacts the inner wall surface of the space 40 in the fixed mold body. Movable type 1 in such a state
The state of 0 and the fixed die 20 is shown in FIG. 4a shows a state of the movable core 15 retracted in the holes 38, 38 by the fixed side cores 24, 25, and FIG.
The state of 5 is shown. As shown in FIG. 4, the side cores 24 and 25 of the fixed mold 20 and the movable cores 14 and 15 of the movable mold 10 are illustrated.
Each end surface (only the movable core 15 is shown in FIG. 4) is formed in an L shape.

A cavity 39 for molding the primary molding portion of the box 50 is formed on the parting surface by the movable mold 10 and the fixed mold 20 in the state shown in FIG. 4 above the parting surface and in the cavity. Voids 36, 36 are formed at positions separated from 39, which serve as cavity portions for molding a part of the secondary formation portion of the box 50. The cavity 39 is formed between the bottom surface of the concave portion of the movable mold 10 and the lower surfaces of the end surfaces of the fixed cores 34, 34 ... Of the fixed mold 20 and the convex end surface of the center core 22. Such a cavity 3
9 , the width of the cavity portion formed between the convex end surface of the center core 22 and the lower surface is narrower than the width of the cavity portion formed between the top surface of the fixed cores.
The cavity portion formed between the lower surface of the convex end surface of the center core 22 is a portion for joining the primary molded body and the secondary molded body of the obtained box body 50, as described later. Further, the gaps 36, 36 are formed by the side cores 24 of the fixed mold 20,
It is formed between the L-shaped end surface of 25 and the L-shaped end surfaces of the movable cores 14 and 15 of the movable mold 10, and is a portion that becomes a cavity that constitutes the end portion of the secondary molding portion of the box 50. .

Next, after the cavity 39 is filled with the first resin to form the primary molding portion, the hydraulic pressure is supplied from the hydraulic passage 30 to the core cylinders 23, 23, and the movable cylinders 16, 16 are also pressurized. By supplying, the center core 22 and the side cores 24, 2 of the fixed mold 20
5 and the movable die cores 14 and 15 of the movable die 10 are both pushed down to bring the movable die 10 and the fixed die 20 into the state shown in FIG. With the movable mold 10 and the fixed mold 20 in the state shown in FIG. 2, the void 36, which is a cavity portion for molding the end portion of the secondary molded body, moves downward, and becomes a cavity portion for molding the secondary molding portion main body. A cavity for forming the secondary forming portion is formed by connecting with the void 42. When the second molding part is molded by filling the second resin in the cavity formed by connecting the voids 36 and 42, and when the mold is opened as shown in FIG.
The box 50 shown in can be obtained.

The box 50 shown in FIG. 6 is sandwiched by a pair of side portions 52, which are primary molding portions, and the band-shaped portion 5 which is a secondary molding portion.
3 is joined. The band-shaped portion 53 and the side portions 52, 52 are joined to each other by a linear joint between the end faces of both portions, and a resin layer 54 made of a second resin that forms the belt-shaped portion 53 on the lower side surface of the side portion 52. Planar joining is done. Therefore, as compared with the conventional box 100 shown in FIG. 7 in which only the end faces of both parts are linearly joined, the joining strength of both parts in the box 50 obtained according to the present embodiment is set to be high. can do.

[0013]

According to the present invention, the molding die can be downsized, and the joining strength between the primary molded body and the secondary molded body of the box can be improved. The boxes used for various meter covers, cassette halves, various cases, etc. can be easily manufactured by melt molding.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a state of a movable die and a fixed die when a molding die is opened.

FIG. 3 is a cross-sectional view showing a state where a molding die is closed and a primary molding portion is molded.

FIG. 4 is a perspective view showing a state of a movable mold and a fixed mold when molding a primary molding part.

FIG. 5 is a cross-sectional view showing a state where a secondary molding portion is molded.

FIG. 6 is a perspective view and a partial sectional view of a box obtained by the molding die of the present invention.

FIG. 7 is a perspective view and a partial sectional view of a conventional box.

[Explanation of symbols]

 10 Movable type 12 Movable type concave part 14, 15 Movable type core 20 Fixed type 22 Fixed type center core 24, 25 Fixed type side core 34 Fixed core 50 Box body 53 Secondary molding part (strip-shaped part) 54 Primary molding part (side part) )

Claims (4)

[Claims] 1. A first resin forming a primary molding portion forming a pair of side portions of a box body, and a bottom portion of the box body which is sandwiched between the pair of side portions and which crosses in a strip shape, and has an end portion. In a molding die of a box, which has physical properties such as hue different from each other with a second resin forming a secondary molding part which constitutes a part of both sides of the box, one of the molding dies is constituted. A fixed-type core core that forms a cavity between the movable-type concave portion and the movable-type concave portion is provided so as to be movable back and forth in the mold opening / closing direction, and the end surface on the parting surface side is a stepped convex end surface, and A pair of fixed side cores, which are slidably in contact with the side wall surface of the fixed center core and are movable back and forth in the mold opening / closing direction, and which face each other with the fixed center core interposed therebetween; The fixed type side core is divided into a fixed core that slides in and out, Moreover, when the fixed center core advances, the top surface of the convex end surface of the fixed center core abuts the concave portion of the movable mold that constitutes the other side of the molding die, and the lower surface of the convex end surface In the cavity formed between the fixed mold, the flat bottom part forming the joint part of the primary molding part that is surface-bonded to the secondary molding part, and the pair of holes formed in the recess wall surface A movable mold core inserted so as to be movable back and forth so that the cavity for molding the end of the secondary molding portion formed by abutting a part of the end surface of the side core can be moved in the mold opening and closing direction, An end face shape of the movable die core that abuts the fixed die side core is a shape that forms a part of an inner wall surface of the movable die recess when the movable die core retracts. . 2. The molding die for a box according to claim 1, wherein a step is formed at each end of the fixed side core and the movable core. 3. The molding die for a box body according to claim 1, wherein the stationary center core and the pair of stationary side cores are incorporated in the insert mold. 4. The molding die for a box according to claim 1, wherein a pair of movable die cores are incorporated in the insert die.