JPH01321062A - Method for separating sprue in high pressure casting - Google Patents

Abstract

PURPOSE:To prevent sticking of a casting product to a pressurizing pin and to stabilize working of the pressurizing pin by inserting the pressurizing pin from opposite side of a pouring hole after pouring molten metal into a die, returning back the pressurizing pin after making a sprue thin thickness, re- inserting and separating the sprue. CONSTITUTION:The pressurizing pin 22 is positioned to the original position of the continuous line in the figure and tip part of an injection device 9 is fitted to the die 1. Successively, a plunger 11 is shifted upward and the molten metal M is poured into a cavity 7 from the pouring hole 8. Further, the pressurizing pin 22 is shifted downward and the tip part is positioned to the min. cross sectional area part 21 in the pouring hole 8. Then, just before or after completing the solidification, the pressurizing pin 22 is shifted upward to return back to the original position. Successively, after completing the solidification, the injection device 8 is retreated, and at the time of shifting again the pressurizing pin 22 downward, the pressurizing pin 22 is hit to the sprue (pa) in the casting product (p). At this time, the thickness of the pouring hole 8 is made thin, and by pressing the pressurizing pin 22, the sprue (pa) is simply cut.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for separating a sprue in high-pressure casting, and more specifically, a method for separating a sprue in high-pressure casting. This invention relates to a sprue separation method in high-pressure casting, in which molten metal is injected at high pressure into a cavity through a spout provided at the bottom.

(Prior Art) Conventionally, this type of high-pressure casting has been carried out using, for example, an apparatus shown in FIG. In the same figure, l is the mold,
Upper mold 2. It consists of an upper mold insert 3, a slide core 4, a lower mold 5, and a lower mold insert 6. The lower mold insert 6 is provided with a pouring port 8 that communicates the cavity 7 with the lower part of the mold l,
On the other hand, below the mold 1, an injection bag 8 is separately provided which can be moved up and down. The injection device 9 includes an injection plunger 11 slidably housed within a sleeve 10. During casting, the tip of the sleeve 10 is fitted and set to the lower end of the lower die 5 facing the pouring port 8 as shown in the figure. Ru. In the set state, the sleeve 1 is moved upward by the injection plunger 11.
0 is injected into the cavity 7 through the pouring port 8, and after injection, the injection plunger 11 is pressed as appropriate.
High-pressure casting is performed by applying pressure at.

In such high-pressure casting, when the mold is opened after solidification, as shown in Fig.
Figure) is separated at the shoulder 6a inside the lower mold insert e, and part of it B
remains inside the lower mold insert B.

Part B of the sprue remaining in this lower mold insert 6 is then removed from the seventh
The knockout pin of the knockout device as shown in the figure! The mold is released by the downward movement of 2, for example, the receiver of the conveyance equipment is
It falls onto the top and is carried out of the system.

(Problem 8 to be solved by the invention) However, according to the conventional sprue separation method in which the sprue A is separated using the mold opening, a large shearing force is applied to the mold 1, especially the lower mold insert 6, and the 6 As shown in figure 6, lower mold insert 6
There was a problem in that the dirt 14 was generated at the corner of the shoulder 13a of the mold, and the life of the mold was significantly reduced. In addition, a dedicated knockout device and knockout process are required to release the separated sprue from the mold, resulting in the problem of prolonging the casting cycle time and increasing equipment costs.

As a sprue separation method, for example, as shown in FIG. There is a method of coagulating it in a separated state (#Opening/closing 8
2-279070).

However, this separation method is possible when applied to so-called gravity casting in which the spout opens upward, and when the injection device is located at the spout as in the high-pressure casting described above, there is a direct line to the spout. 17 cannot be inserted, making it impossible to apply it to this type of high-pressure casting.

The present invention has been made in view of the above-mentioned conventional problems in high-pressure casting, and its objectives are to prevent damage to the mold by making it possible to separate the sprue with a small force, and to create a special The object of the present invention is to realize a sprue separation method that simplifies sprue separation by making it possible to release the mold without using a knockout device.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention provides a method for high-pressure casting, after injecting molten metal into the mold.

Inserting a pressure pin into the cavity from the side opposite to the pouring port of the mold to reduce the opening area of the pouring port, allowing solidification to proceed, and returning the pressure pin to its original position immediately before or after completion of solidification;
The gist of the invention is that after the injection device is separated from the mold, the pressure bottle is inserted again to separate the sprue.

(Function) In the sprue separation method for high-pressure casting with the above configuration, the wall thickness of the sprue of the cast product becomes thinner by reducing the opening area of the pouring spout with a pressure pin, and the sprue can be easily closed by reinserting the pressure pin. Separated. Furthermore, by temporarily returning the pressure bottle to its original position immediately before or after the completion of solidification, it is possible to prevent the casting from sticking to the pressure pin, and the operation of the pressure pin is stabilized over a long period of time.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

Figure t51 shows a high-pressure casting apparatus to which the gate separation method according to the present invention is applied. The basic structure of this device is the same as that shown in Fig. 5 above, so the same parts as shown in Fig. 5 are given the same reference numerals.
The explanation will be omitted. In the unimplemented example, the pouring spout 8 provided in the lower mold insert 8 has a minimum cross section 2 near the opening end on the cavity 7 side. It has a shape in which the diameter is tapered upward and downward from this minimum cross-section portion 21. Furthermore, a pressure pin 22 is slidably installed inside the mold 1 so as to penetrate the upper mold 2 and the upper mold insert 3 in the vertical direction. The pressure pin 22 has its lower end facing the pouring port 8, and its upper end is connected to a drive cylinder 23 fixed to the upper die 2 via a coupling 24. And the pressure pin 22 is
By the operation of the drive cylinder 23, the tip can be arbitrarily positioned between the solid line position (original position) where the tip slightly protrudes into the cavity 7 and the broken line position where the tip is located at the minimum cross section 2I of the pouring spout 8. It has become.

Hereinafter, the sprue separation method carried out in the high-pressure casting apparatus configured as described above will be explained with reference also to FIGS. 2 to 4.

During casting, the pressure pin 22 is positioned in advance at the original position shown by the solid line in FIG. The injection plunger 11 is moved upward to inject the molten metal X stored in the sleeve 10 into the cavity 7 through the pouring port 8. A few seconds after the completion of this injection, the drive cylinder 23 is operated under, for example, timer control to move the pressurizing pin 22 downward, and the tip of the pressurizing pin 22 is inserted into the minimum cross section 21 of the pouring spout 8 as shown in FIG. Position. And then...
The coagulation is allowed to proceed, and the pressurizing bottle 22 is moved upward by actuation of the drive cylinder 23 just before or after the completion of coagulation, and is returned to its original position as shown in FIG. This pressure pin 22
Due to the return of the pressure pin 22, a gap 0 is formed inside the cavity 7, which is a trace of the removal of the pressure pin 22.

Next, after waiting for complete solidification, the injection device 21 is opened as shown in FIG.
B is retracted and its sleeve 9 is separated from the mold 1. Thereafter, by actuation of the drive cylinder 23, the pressure bottle 22 is moved downward as shown in FIG. Due to this downward movement, the pressure bottle 22 hits the sprue Pa of the casting P, and the sprue Pa
Press down. At this time, due to the existence of the void 0,
The wall thickness of the sprue portion corresponding to the minimum cross section 21 of the pouring spout 8 is extremely thin, and the sprue Pa is easily separated from this portion by the pressure of the pressure bottle 22. The divided sprue Pa is released from the mold by further downward movement of the pressure bottle 22, and as shown in FIG. will be transported to.

In this manner, the sprue can be easily separated by utilizing the movement of the pressurizing bottle 22, and therefore the mold 1 is prevented from being damaged by debris or the like. In addition, by once returning the pressure pin 22 to its original position, it is possible to prevent the casting product P from sticking, and to ensure that the pressure pin 22 is smoothly moved over a long period of time. After roughly injecting the molten metal X into the cavity 7, by inserting the pressure pin 22 into the cavity 7, the occurrence of casting defects such as blowholes is suppressed, and a sound cast product can be obtained. Become.

Note that the shape of the sprue 8 or the insertion depth of the pressure bottle 22 are not limited to the embodiments described above, and can be arbitrarily changed depending on the type, size, etc. of the cast product.

(Effects of the Invention) As described in detail above, according to the sprue separation method in high-pressure casting according to the present invention, the sprue can be easily separated by utilizing the movement of the pressure pin, resulting in damage to the mold. This has the effect of significantly extending the life of the mold. In addition, by returning the pressure bottle to its original position, the casting product is prevented from sticking to the pressure pin, and smooth movement of the pressure pin can be guaranteed over a long period of time, increasing the reliability of the device. The effect of significantly improving this can be obtained. Furthermore, a special knockout device and a knockout process for all the separated sprues Pa are no longer necessary, resulting in the effects of shortening the casting cycle time and reducing equipment costs.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a high-pressure casting apparatus to which the sprue separation method according to the present invention is applied, and FIGS. 2 to 4 are cross-sectional views showing the sprue separation method in the present high-pressure casting apparatus in order. , FIGS. 5 to 7 are cross-sectional views showing a conventional sprue separation method in high-pressure casting, and FIG. 8 is a cross-sectional view showing a conventional sprue separation method in gravity casting. l ... Mold 7 ... Cavity 8 ... Pouring port 9 ... Injection device 22 ... Pressure bottle ' 23 ... Drive cylinder M ... Molten metal P ... Casting product Pa ... Yuguchi patent applicant Toyota Motor Corporation agent
Patent Attorney Yumi Sae (and 2 others) Figure 1 $2 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) In high-pressure casting, in which molten metal is injected at high pressure into a cavity from an injection device arranged vertically movably below the mold through a pouring hole provided at the bottom of the mold, the molten metal is injected into the mold. After that, a pressure pin is inserted into the cavity from the side opposite to the pouring port of the mold to reduce the opening area of the pouring port, solidification is allowed to proceed as it is, and the pressure pin is returned to its original position just before or after solidification is completed. . A sprue separation method in high-pressure casting, characterized in that after the injection device is separated from the mold, the pressure pin is inserted again to separate the sprue.