JPH0716779B2 - Lower pressure type high pressure casting equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower pressurization type high pressure casting apparatus for casting an aluminum wheel or the like for a vehicle.

(Prior Art) As a casting device for manufacturing high strength parts such as aluminum wheels, there is a lower pressure type high pressure casting device developed by the present applicant (see: "Production term encyclopedia" Toyota Motor Corporation). Published by Toyota Engineering Society, December 24, 1985,
P33 ~ P34).

In this high-pressure casting apparatus, as shown in FIG. 7, an injection cylinder 3 in which a plunger 2 is operated in the vertical direction is provided below a casting mold 1, and an upper part of the injection cylinder 3 is provided with an injection cylinder 3. A molten metal reservoir member 4 is provided for storing the molten metal B to be injected into the cavity A of the mold 1 by the operation of the plunger 2. Further, the injection cylinder 3 is fixedly mounted on the bracket 5, and the hot water pool member 4 is slidably mounted on the bracket 5, and the flange portion 2a provided on the plunger 2 is engaged by the forward movement of the plunger 2. The water pool member 4 can be moved forward. The bracket 5 is rotatably supported by the link mechanism 6.

A pouring port 7 is formed in the mold 1, and the tip of the pouring member 4 is fitted into the pouring port 7 to enable pouring.

Explaining the operation of this lower pressure type high pressure casting device,
The molten metal B is poured by inclining the pool member 4 (state of FIG. 7 (a)). Then, after returning the pouring member 4 to the vertical position (state of FIG. 7 (b)), the injection cylinder 3 is operated to move the pouring member 4 forward by the plunger 2, and the tip of the pouring port of the die 1 is poured. 7 (state of FIG. 7 (c)). Then, the injection cylinder 3 is operated and the molten metal B in the molten metal pool member 4 is extruded by the plunger 2 to fill the cavity A (state of FIG. 7 (d)).

At this time, the molten metal B is filled into the cavity A at a low speed, and injection is performed so that a high pressure is applied in the solidification process after filling.

When molded in this way, a dense and fine structure is obtained, and a high-strength cast product is manufactured.

Then, the cast product formed in this manner is removed of the excess thickness portion (biscuit) generated at the pouring port of the cast product, for example, by the method disclosed in Japanese Patent Application No. 53-114111.

This will be schematically described with reference to FIGS. 5 and 6 (a) and (b). First, as shown in FIG. Medium type 9, lower type 10
A metal-made punching metal 11 for removing the aluminum oxide film generated on the surface of the molten aluminum so as not to mix with the molten metal B into the cavity A is attached to the pouring hole 7 of the mold 1 (actual application). (See Japanese Patent Publication No. 57-127610).

In addition, this punching metal 11 is used for the casting hole 12 of the casting 12.
It is also for facilitating the cutting for removing the surplus portion (biscuit) 13 generated in the. Then, in order to prevent the punching metal 11 from rising when pouring into the cavity A, a cast iron ring 14 is placed on the upper surface of the punching metal 11.

Then, the molten metal B in the molten metal pool member 4 is pushed into the cavity A by the plunger 2 and then pressurized to perform casting.

Next, as shown in FIG. 6 (a), the excess wall portion 13 generated in the pouring port 7 during casting and molding is removed by allowing the die 12 to receive the cast product 12 released from the mold 1, By pressing the central portion with the punch 16, the excess thickness portion 13 is cut and removed from the punching metal 11 as shown in FIG. 6 (b).

(Problems to be Solved by the Invention) However, the above-mentioned conventional lower pressure type high-pressure casting apparatus has the following problems.

As can be seen from FIG. 5, the molten metal B is dropped and filled by its own weight into the molding portion X of the cavity A for molding the outer ring portion of the aluminum wheel (drop-filling).

As a result, the molten metal B entrains gas when it falls by its own weight, which easily causes a blowhole defect and causes a bulge during heat treatment in a subsequent process, which causes a defective product.

Further, since the molten metal B is not continuously filled, the molten metal B is likely to solidify in the course of filling and cause poor flow of molten metal even if it is cooled. Therefore,
In order to improve the flow of molten metal, it is necessary to widen the entire molding site, which increases the wall thickness of the product and impairs the weight reduction which is an advantage of the aluminum wheel.

Further, it is conceivable that the mold 1 is turned upside down in order to eliminate the drop filling, but in that case, the pouring port 7 is on the side of the design surface of the product (the surface that becomes the appearance of the product). Then, as described above, since the excess thickness portion 13 generated in the pouring port 7 is cut in a planar shape at the location of the punching metal 11, if the design surface side is the pouring port 7, the cutting process is performed in the post-processing, Since the product shape must be carved out and the productivity is very poor, the pouring port 7 is not generally provided on the design surface side.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a lower pressurizing high-pressure casting apparatus capable of providing a pouring port on the design surface side without lowering productivity. To form thin, lightweight castings of good quality.

(Means for Solving Problems) Means for solving the above problems will be specifically described with reference to FIG.

In a lower pressurization type high pressure casting machine that fills molten metal from a pouring port formed on the lower side of the cavity by an injection cylinder provided below the mold, the design surface of the cast product to be molded is the pouring port. The cavity 21 is configured to be on the 23 side, and the pouring port 23 is provided with a nesting ring 24 for molding a part of the design surface of the cast product.

(Function) As described above, the cavity 23 is formed by disposing the nesting ring 24 for molding a part of the design surface in the pouring hole 23 of the cavity 21 configured so that the pouring hole 23 side becomes the design surface. Since a part of the design surface can be formed in the pouring port portion of, the cutting process in the post process is not necessary to obtain the product shape on the design surface side.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIGS. The same members as those of the related art will be designated by the same reference numerals, and detailed description thereof will be omitted.

Below the die 17, an injection cylinder 3 is provided, in which the plunger 2 operates in the vertical direction. Above the injection cylinder 3, there is provided a pool member 4 for storing the molten metal B to be injected into the mold 17 by the operation of the plunger 2, and the bracket 5 includes the injection cylinder 3 and the pool member 4. It is assembled. The injection cylinder 3 and the pool member 4 are rotatably supported by a link mechanism 6. The hot water pool member 4 is moved up and down by the flange 2a provided on the plunger 2 engaging with the hot water pool member 4 as the plunger 2 operates. It consists of 19, lower mold 20, each mold 18,1
The cavities 21 for molding the aluminum wheels are constituted by 9,20. Then, the lower mold 20 is provided with a molding surface 22 for molding the product shape on the design surface side that is the appearance of the aluminum wheel, and a pouring port 23. The pouring port 23 is provided with a nesting ring 24 which is a main part of the present invention. The nesting ring 24 is a product shape on the design surface side of the hub mounting portion of the aluminum wheel, that is, one of the design surfaces. It is shaped so as to mold the part and is placed on the punching metal 11.

The operation of the above configuration will be described.

As in the conventional case, after pouring the molten metal B in the pool member 4, the injection cylinder 3 is operated and the plunger 2 is advanced to fit the tip of the pool member 4 into the pouring port 23 of the lower mold 20. . Subsequently, as shown in FIG. 2, the molten metal B is filled into the cavity 21 at a low speed by the plunger 2.

At this time, the filled molten metal B is pressed from below and flows upward in the forming portion X where the outer ring portion of the aluminum wheel is formed, and unlike the conventional drop due to its own weight, gas entrapment is greatly reduced. , The flow of hot water is also improved.

Next, when the molten metal B is filled, it is pressurized at high pressure by the plunger 2 to solidify the molten metal B.

In this way, after the molded casting 25 molded is released,
Insert it into the center hole 25a with a pin 26
Through and the excess thickness portion 27 is cut and removed from the punching metal 11 (see FIG. 3). Subsequently, the pin 27 is inserted through the hub bolt hole 25b and the nesting ring 24 is pressed to remove it from the casting 25.

In this way, since the product shape on the design surface side of the aluminum wheel is formed by the nesting ring 24, the design surface is also formed on the pouring port portion of the cavity 21, which could not be formed in the conventional casting process. Since it can be molded, even if the pouring port 23 side is molded as the design surface,
There is no need to perform a cutting process as a post process.

(Effects of the Invention) As described in detail above, according to the present invention, in the high-pressure casting apparatus of the lower pressurizing method, by disposing the nesting ring for molding a part of the design surface of the casting in the pouring port. Even if the cavity is formed such that the design surface is on the pouring port side, the product shape of the design surface can be obtained without cutting.
Further, according to this cavity structure, unlike the conventional case, the filling of the molten metal is not the down-filling, the molten metal flow in the entire molding site is improved, and the gas entrainment and the defective molten metal flow do not occur.

Therefore, defective molding can be prevented, the outer ring portion can be made thin, and a cast product with high productivity and high strength can be provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing one embodiment of a lower pressurization type high pressure casting apparatus of the present invention, and FIG. 2 is a main part showing a state during molten metal filling in the high pressure casting apparatus shown in FIG. FIG. 3 is a longitudinal sectional view showing a state in which a surplus portion is removed from a cast product formed by the high pressure casting apparatus shown in FIG. 1, and FIG. 4 is a high pressure casting apparatus shown in FIG. FIG. 5 is a vertical cross-sectional view showing a state in which the insert ring is removed from the molded cast product, FIG. 5 is a main-part vertical cross-sectional view showing a state of the conventional high-pressure casting apparatus in a molten metal filling state, and FIG. FIG. 6 (a) is a longitudinal sectional view showing a state before the removal, FIG. 6 (b) is a longitudinal sectional view showing the state after the removal, FIG. (a), (b), (c), (d) is a longitudinal cross-sectional view showing an operating state of a lower pressure type high pressure casting apparatus. 17 …… Mold 21 …… Cavity 23 …… Pouring spout 24 …… Nesting ring

Claims (1)

[Claims] 1. An injection cylinder provided below a mold,
In a lower pressure type high pressure casting machine that fills molten metal from a pouring port formed on the lower side of the cavity and casts it, the cavity of the mold is constructed so that the design surface of the cast product to be molded is on the pouring port side. A lower pressurizing high-pressure casting apparatus is characterized in that an insert ring for forming a part of the design surface of the cast product is provided in the pouring port.