JPH0242581B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a vertical die casting method and method which can be applied to the casting of circular products cast with a center gate, such as wheels for automobiles and motorcycles. Regarding equipment.

(Prior Art) Wheels for automobiles and motorcycles are usually cast using a vertical die-casting device, but wheel casting has the following limitations.

(1) Because the casting weight is large, the diameter of the injection plunger becomes large.

(2) A large injection plunger cannot be used on one side of the cast product because it leaves a cast surface pattern on the product.

Therefore, in the past, a method of casting using the apparatus shown in FIG. 4 has been adopted out of necessity.

That is, a cavity e is formed on the mutually opposing surfaces of a fixed die b attached to a fixed die plate a and a movable die c attached to a movable die plate (not shown), and this cavity is formed on the fixed die b side. The injection sleeve f is in communication with e.
will be established.

This first sleeve f is provided with a hot water supply port (not shown) to supply the molten metal h, and an injection plunger g is provided in the injection sleeve f.
is in a state of being inserted.

Note that i is an iron straining net to prevent coagulated pieces from getting into the cavity e. Further, d is the diameter of the injection plunger, j is the biscuit part, A is the surface where the cast surface pattern is left as a product, and D is the center hole part of the cast product that will be removed later.

Therefore, in casting, after supplying the molten metal h into the injection sleeve f with the movable mold c superimposed on the fixed mold b, the injection plunger g is raised and the molten metal h is passed through the strainer net i. The molten metal h is cast into the cavity e to obtain a cast wheel.

(Problem to be solved by the invention) However, such prior art
I had the following problem. That is, a) When the molten metal h being filled reaches part B, it flows to part C due to gravity, and as the molten metal h that has flowed in first begins to solidify, it eventually becomes under strong pressure (1000~
1500Kg/cm ² ).

b) In order to make it difficult to solidify, it is necessary to raise the temperature of the molten metal h by about 100°C higher than usual, which results in a lot of energy loss.

c) The life of the mold is short due to high temperature and pressure.

d) It is necessary to remove the biscuit part j in post-processing, resulting in poor productivity.

There were other problems.

The present invention was made based on the above circumstances, and
The purpose is to provide a vertical die casting method and apparatus with good production efficiency, which allows die casting products such as wheels to be cast using normal die casting methods without raising the temperature and pressure.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a small-diameter plunger concentrically on the injection plunger, uses a three-ply mold, and has two upper movable molds. After forming the cavity, a gate hole into which the small-diameter plunger is inserted is formed in the lower part of the two movable molds, and after filling the cavity with molten metal,
The small-diameter plunger is pressed to penetrate the biscuit portion and compress the solidifying molten metal, thereby generating plastic flow and separating the gate portion and the biscuit portion.

(Function) That is, in the present invention, by doing as described above, it is possible to sequentially pour the molten metal from the lower part of the cavity, and there is no need to apply strong pressure or raise the temperature to high temperatures as in the past, and the structure of the apparatus is simplified. This makes it possible to improve casting efficiency and extend the life of expensive molds. Moreover, good casting can be performed in a state where plastic flow is generated by the movement of the small-diameter plunger. Further, since the gate portion and the biscuit portion are separated, post-processing for removing the biscuit portion is not required, and productivity can be improved.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, numeral 1 is a fixed mold attached to a fixed die plate 2, and numerals 3 and 4 are a lower mold and an upper mold of two movable molds superimposed on the upper part of the fixed mold 1.

Hereinafter, the definition of a movable die described in the present invention is not limited to a die attached to a movable die plate (not shown), but is moved in the direction of the clamping and opening operation during the clamping and opening operation. The movable mold includes the movable mold that moves.

The lower mold 3 and upper mold 4 of the movable mold are guided by a plurality of tie bars (not shown) so as to be able to move up and down in the direction toward and away from the fixed mold 1, and are tightened via a movable die plate (not shown). It's summery.

Further, an injection sleeve 5 is provided so as to pass through the fixed mold 1 and the fixed die plate 2, and the injection sleeve 5 has an injection plunger 6.
is in a state of being inserted.

The injection plunger 6 has a double structure consisting of a main plunger 7 and a small diameter plunger 8 provided concentrically with the main plunger 7, each of which is moved up and down by a hydraulic cylinder (not shown).

Further, a cavity 10 is formed in the mutually opposing surfaces of the lower mold 3 and upper mold 4 of the movable mold, and a cavity 10 is formed in the lower mold 3 of the movable mold at a position facing the small diameter plunger 8. A gate hole 11 consisting of a cylindrical hole is formed, and the lower center of the cavity 10 and the inside of the injection sleeve 5 are in communication with each other.

At the bottom of the injection sleeve 5, there is a hot water pipe 1 connected to a pressure feeding hot water supply device such as an electromagnetic pump (not shown).
2 is connected, and the molten metal 1 is placed inside the injection sleeve 5.
The structure is such that it can supply 3.

Further, the lower die 3 of the movable mold has a protrusion 14 at the periphery of the opening at one end of the gate hole 11 facing the terminal end of the injection sleeve 5, and a concave portion around the inner wall of the terminal end of the injection sleeve 5 for capturing solidified pieces. Hot water pool part 15
is beginning to form.

Note that 16 is a core located at the center of the cast product. Further, 20 is a core mold which can be moved laterally by a hydraulic cylinder (not shown), and this core mold may be unnecessary depending on the shape of the cast product.
Further, A is a surface on which a cast surface pattern is left.

By simultaneously raising the main plunger and the small-diameter plunger 8 constituting the injection plunger 6, the molten metal 13 previously supplied into the injection sleeve 5 through the hot water supply pipe 12 is fed into the cavity 10 through the gate hole 11. Inject.

FIG. 1 shows a state in which the molten metal 13 is cast halfway into the cavity 10.

Furthermore, by raising the main plunger 7 and the small diameter plunger 8, the molten metal 13 is transferred to the cavity 1.
It will be completely injected into 0.

At this time, the solidified pieces form a concave part 15 around the inner wall of the terminal end of the injection sleeve 5 by the protrusion 14 formed on the opening periphery of the gate hole 11, and the solidified pieces form a concave part 15 on the inner wall of the injection sleeve. The generated solidified pieces are collected and captured to prevent them from flowing into the cavity 10. Therefore, there is no need for a sieving net as in the past, and automation is possible.

When the casting of the molten metal 13 into the cavity 10 is completed, this completion state is detected by a detection means (not shown), such as a pressure switch that detects a change in the oil pressure of a hydraulic cylinder that operates the injection plunger 6, or a limit switch that detects the stroke of the injection plunger 6. When the detection signal is detected, the small diameter plunger 8 starts to rise due to this detection signal.

Then, the tip of the small-diameter plunger 8 is plunged into the cavity 10 into the molten metal 13 that has already been poured, compressing it at a higher pressure and causing the solidifying molten metal 13 to undergo plastic flow.

It has already been demonstrated that this plastic flow has the effect of improving the strength of cast materials, and it is a known fact.

Figure 2 shows the small diameter plunger 8 after the casting is completed.
The biscuit 17 is shown passing through and fitted into the gate hole 11, and the biscuit portion and the gate hole portion are separated.

Figure 3 shows the lower mold 3 of the movable mold after the state shown in Figure 2.
The upper mold 4 is then raised to perform a so-called mold opening operation, and the biscuit 17 remaining at the end of the injection sleeve 5 is extruded and discharged by the injection cylinder 6. Of course, the small diameter plunger 8 will be machined and removed from the biscuit 17 immediately before this operation.

Although the above-mentioned embodiment has been described as a vertical die-casting device, it is of course applicable to a horizontal die-casting device.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the invention.

〔Effect of the invention〕

As explained above, the present invention makes it possible to sequentially pour the molten metal from the lower part of the cavity, eliminating the need to apply strong pressure or raise the temperature as in the past, simplifying the structure of the device, and improving casting efficiency. It becomes possible to improve the quality of the mold and extend the life of expensive molds. Moreover, good casting is possible in a state where plastic flow is generated. Furthermore, since the gate part and the biscuit part are separated, only the biscuit part can be discharged separately, making post-processing easier and improving productivity.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a schematic sectional view showing the state in which molten metal has been poured halfway into the cavity, and Figure 2 showing the state in which the molten metal has been poured halfway. FIG. 3 is a schematic sectional view showing the biscuit discharging state; FIG. 4 is a schematic sectional view showing the state;
The figure is a schematic sectional view showing a conventional example. 1... Fixed mold, 2... Fixed die plate, 3... Moving die (lower die), 4... Moving die (upper die), 5... Injection sleeve, 6... Injection plunger, 7... Main plunger, 8... Small diameter Plunger, 10...Cavity, 1
1... Gate hole, 13... Molten metal, 14... Projection, 15
...Coagulated piece trapping part, 17... Biscuit.

Claims (1)

[Scope of Claims] 1. Filling a cavity consisting of two movable molds with molten metal by moving an injection plunger consisting of a main plunger and a small-diameter plunger provided concentrically with the main plunger; After completion,
The small-diameter plunger is moved to penetrate the biscuit part and fit into the gate hole formed in the lower mold of the movable mold, compressing the solidifying molten metal to generate plastic flow and sealing the gate part and the biscuit part. A vertical die casting method characterized by separating the two. 2. An upper mold of the movable mold, a lower mold of the movable mold that overlaps with the upper mold to form a cavity at mutually opposing parts and has a gate hole, and an injection sleeve that comes into contact with the lower mold of the movable mold. a main plunger that is fitted into the injection sleeve fixed to the fixed mold and injects the molten metal into the cavity; and a main plunger that is installed concentrically with the main plunger and completes the filling of the molten metal into the cavity. 1. A vertical die-casting device characterized by comprising: a small-diameter plunger which is then moved and fitted into a gate hole; 3. The lower mold of the movable mold has a protrusion at the periphery of the opening at one end of the gate hole corresponding to the end of the injection sleeve,
3. The vertical die-casting apparatus according to claim 2, wherein a solidified piece trapping pool is formed around the inner wall of the injection sleeve.