JPS6333448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molding device for molding a container whose interior is divided by partition walls.

For example, in a washing machine, as shown in FIG. Some devices have a mouth (not shown) that can be opened and closed by an opening and closing mechanism. Figure 2 shows a conventional mold device for integrally molding such a washing tub a from plastic. In the figure, d is the lower mold, and e is the two molds that form the inside of the tub and the inside of the drain chamber c. After molding, the mold is removed by moving the upper mold e upward using a vertically movable upper mold with fixed f and g. However, in the above structure, in order to improve the mold removal performance, it is necessary to provide draft angles θ ₁ and θ ₂ on both sides of the vertical rib b. There were problems in that the thickness t became considerably thick, causing wall sinkage, and that the cooling effect deteriorated and the time required for molding each piece became longer.

The present invention was made in view of the above circumstances, and
On one side of the partition wall that divides the inside of the container, the draft angle can be made small or zero,
To provide a mold device that can reduce the wall thickness of the base of a partition wall due to draft angle.

Hereinafter, an embodiment of the present invention will be described as applied to a mold device for molding a washing tub of a washing machine with reference to FIGS. 3 to 5. As shown in FIG. 5, the washing tub 1 molded by the molding device of this embodiment has a washing chamber 3 and a drain chamber 4 separated by vertical ribs 2 corresponding to partition walls.
There is a drain port 4 at the bottom of the drain chamber 4.
a is formed. The above-mentioned washing tub 1 is integrally molded from plastic, and the structure of the mold is explained with reference to FIG. There is. 7 is the upper mold which is the mold body, and this upper mold 7
has a first mold 8 that forms the washing chamber 3 and a second mold 9 that forms the drain chamber 4, and the first mold 8
is fixed to the base mold 10 with screws 11 to constitute the upper mold main body 12, and the second mold 9 is slidably inserted into the fitting recess 13 formed between the base mold 10 and the first mold 8. The rod 14a of the cylinder 14 is fixed to the base mold 10. The base mold 10 is connected to a ram of an injection molding machine, and is moved in the vertical direction along the dashed line A in FIG. 3 by the operation of the ram. On the other hand, when the base mold 10 is moved, the second mold 9 moves together with the first mold 8 (therefore, the entire upper mold 7, which is the mold main body, moves), and when the cylinder 14 is activated, it moves independently as indicated by the dashed-dotted line in FIG. It is designed to move in the vertical direction along B. When the upper mold 7 is aligned with the lower mold 5 as shown in FIG. A cavity C is formed for forming the first and second molds 8,
Between 9 and 9 is a cavity D for forming the vertical rib 2.
is formed, and washing tub 1 in cavity C is
Each side surface of the lower mold 5 and the first and second molds 8 and 9 forming a portion corresponding to the peripheral wall of the mold is provided with a draft angle of an angle θ ₁ . Also, among the side surfaces 8a and 9a of the first and second molds 8 and 9 corresponding to the cavity D, the side surface 8a of the first mold 8 has a draft angle that is the same as the above angle θ ₁ . , the side surface 9a of the second mold 9 has no draft angle, and the side surface 9a is a vertical surface. The independent movement direction of the second mold 9 by the cylinder 14 is inclined by an angle θ ₂ with respect to the movement direction of the upper mold 7 along line A, and the inclination angle θ ₂ is defined as the draft angle. It is set slightly smaller than θ ₁ . Incidentally, the inclination angle of the second die 9 in the direction of independent movement may be set equal to the draft angle θ ₁ .

In the above configuration, the upper mold 7 is aligned with the lower mold 5,
The heated and melted plastic is supplied from the nozzle of the injection molding machine through the spool 6 into the cavities C and D. When the plastic filled in the cavities C and D has cooled and solidified, the pressure fluid supply path to the cylinder 14 is first switched, and the rod 14a, which is in the advanced state, is retreated. Then, as shown in FIG. 4, the second mold 9 is pulled up by the rod 14a and moved in the direction of arrow E (mold release operation). The mold release operation direction of the second mold 9 is inclined by an angle θ ₂ with respect to the vertical surface 2a of the vertical rib 2 formed by the vertical side surface 9a of the second mold 9. The mold 9 has vertical ribs 2 as it releases the mold.
The vertical rib 2 is separated obliquely upward from the surface 2a at an angle of θ ₂ , and a predetermined gap F is created between the vertical rib 2 and the second mold 9. In addition, since the inclination angle θ ₂ of the second mold 9 in the releasing operation direction is set smaller than the draft angle θ ₁ attached to the peripheral wall of the washing tub 1, the second mold 9 is attached to the peripheral wall of the drain chamber 4. It also separates from the peripheral wall of the washing tub 1 constituting the washing tub 1, and a predetermined gap G is created between the peripheral wall and the second mold 9. However, the gap G is narrower than the gap F. After the mold release operation of the second mold 9 is completed, the entire upper mold 7 is pulled up by the ram of the injection molding machine and moved in the direction of arrow A (extraction operation), thereby releasing the first and second molds 8 and 9. is pulled out from inside the washing tub 1 (see FIG. 5), and finally a knock pin (not shown) provided on the lower mold 5 pushes up the washing tub 1 and pulled out from the lower mold 5. In this case, the second mold 9 has already been separated from the inner surface of the drain chamber 4 due to the previous mold release operation, and the peripheral wall of the washing tub 1 and the surface of the vertical rib 2 on the laundry chamber 3 side are provided with a draft angle. Since the mold releasability of the first mold 8 is also good, the upper mold 7 is smoothly pulled out from the inside of the washing tub 1. Further, the washing tub 1 is also smoothly pulled out from the lower mold 5 due to the draft angle provided on its peripheral wall.

As described above, according to the present embodiment, since the releasing operation direction of the second mold 9 is inclined by an angle θ ₂ with respect to the releasing operation direction of the upper mold 7, the drainage chamber 4 of both surfaces 2a and 2b of the vertical rib 2 is Regarding the side surface 2a, even if it is a vertical surface,
By tilting the second mold 9 in the mold release operation direction, it is possible to obtain the same effect as when a draft angle is provided. Therefore, of both surfaces 2a and 2b of the vertical rib 2, only the surface 2b on the washing chamber 3 side needs to be provided with a draft angle, and as a result, while the thickness of the upper end of the vertical rib 2 is the same as before, the lower end is The wall thickness of the base can be made considerably thinner than before, and because of the thinner wall thickness, the problem of wall sinkage can be solved, and the cooling and solidification time of the molten plastic, as well as the molding time required for each washing tub, are shortened, which improves productivity. improves.

Moreover, in the case of the conventional mold device, the vertical rib b is wedge-shaped between the two molds f and g, and both molds f and g are released simultaneously. There was a problem in that anti-mold release force was generated due to the wedge action of b, impairing the mold releasability of molds f and g, but in this example, the first and second molds Since molds 8 and 9 are not released simultaneously, and the second mold 9 is released before the first mold 8, no anti-mold release force is generated due to the wedge action of the vertical ribs 2, resulting in good mold release properties. Become.

In the above embodiment, the surface 2a of the vertical rib 2 on the drainage chamber 4 side is a vertical surface, but as shown in FIG. In this case, when the inclination angle of the surface 2a is θ ₃ , the inclination angle θ ₂ of the second mold 9 in the releasing operation direction is θ It is sufficient to set so that ₁ > θ ₂ > θ ₃ .

As explained above, the present invention is provided with a cylinder that performs a mold release operation on the second mold prior to the removal operation of the mold body, and the direction of the mold release operation is tilted at a predetermined angle with respect to the direction of the release operation of the mold body. As a result, of the partition wall formed between the first and second molds, the surface on the second mold side may not have a draft angle at all or even if it has one. Since only a small piece is required, the wall thickness at the proximal end of the partition wall can be made thinner, preventing wall shrinkage, reducing the cooling and solidifying time, and eliminating the anti-mold release force that causes wedge action on the partition wall. , mold releasability is improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a washing tub with a part removed, FIG. 2 is a sectional view of a conventional molding device, and FIGS. 3 to 5 show an embodiment of the molding device of the present invention in different states. FIG. 6 is a cross-sectional view of main parts showing another embodiment of the present invention. In the figure, 1 is a washing tub (container), 2 is a vertical rib (partition wall), 5 is a lower mold, 7 is an upper mold, 8 and 9 are first and second molds, 12 is a mold body, and 14 is a cylinder. It is.

Claims (1)

[Claims] 1. For molding a container whose interior is divided by a partition wall, a first mold forming one chamber and a second mold forming the other chamber inside the container partitioned by the partition wall. a mold body having a mold of;
a cylinder for releasing the second mold prior to the removal operation of the mold body, and the direction of the release operation of the second mold by the cylinder is set at a predetermined angle with respect to the direction of the removal operation of the mold body. A molding device characterized in that the second mold is tilted so that the second mold is separated from the partition wall as the mold is released.