JPH02307660A - Locally pressurizing casting apparatus - Google Patents

Abstract

PURPOSE:To prevent the development of casting defect from occuring by arranging heating means for heating pressurizing pins. CONSTITUTION:Dies 1 are constituted with an upper die 3 and a lower die 2 and in these, cavity R for product is formed and filled up with molten metal M. The pressurizing pins 11, 12 are faced on the cavity R for product and the molten metal is locally pressurized with these by opening a pressurizing cylinders 14, 15. Then, the pressurizing pins 11, 12 are heated with heating means composed of induction coils 17, 18 to pressurize the molten metal M. By this method, the pressurization can be applied at the optimum timing according to progressing condition of solidification.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention casts a molten metal filled in a product space of a mold while locally pressurizing it with a pressure pin.

The present invention relates to a local pressure casting device.

Conventional technology die casting] - As one of the casting methods, for example, JP-A-62-1
As disclosed in Japanese Patent No. 6858, the molten metal filled in the product space of the mold is locally pressurized with a predetermined pressure using a pressure pin driven by a cylinder. There is a method that aims at densifying the structure while preventing one defect by casting in sections.

Problems to be Solved by the Invention In such a local pressure casting method, it is most ideal to pressurize after the filling of the molten metal into the space of the product is completed and to a certain extent that the molten metal is solidifying. However, since solidification has progressed from an early stage, especially in areas far from the gate, waiting for the filling of the molten metal into the product space as described above is not the optimal time to pressurize. Sometimes I miss it.

As a result, by the time the pressure is actually applied, solidification has progressed too much and the sufficient effect of local pressure cannot be obtained, and "sinkage cavities" still occur, especially in thick wall areas far from the cage.
Casting defects such as

The present invention was made in view of the above problems.
It is an object of the present invention to provide a casting apparatus which has a relatively simple structure, but which can apply pressure at an optimal timing depending on the solidification state of the molten metal in the pressurized area.

Means for Solving the Problems As described above, the present invention provides a casting device in which the molten metal filled in the product space of a mold is locally pressurized by a pressure pin whose tip faces the product space. The apparatus is characterized in that a heating means for heating the pressure pin is provided.

Effect: According to this structure, by heating the pressurized area of the molten metal with the pressurizing pin heated by the heating means, the progress of solidification in the vicinity of the pressurized area can be substantially delayed. the result,
The degree of freedom in the timing of applying pressure using the pressure pin is large (particularly in areas far from the gate part, there is no delay in the timing of applying pressure, and it is possible to apply pressure at the optimal timing according to the progress of solidification. Casting defects such as shrinkage cavities can be prevented.

Embodiment FIGS. 1 and 2 are diagrams showing a more specific embodiment of the present invention. In the same figure, 2 is a lower mold that constitutes the mold 1, and 3 is the same (upper mold, the lower mold 2 is fixed to the die plate 4, while the upper mold 3 is a support that can be raised and lowered via the die plate 5. It is fixedly supported by a plate 6.A product part space (cavity) R is formed by matching the lower mold 2 and the upper mold 3, and the molten metal M pushed up by the plunger 7 is formed in the product part space R. is filled through the gate part 8. 9 is a sleeve.

The upper mold 3 has a plurality of pressure pins 1 integrated with a pressure plate 10.
1.12 is inserted, and the tip of each pressure pin 11.12 is located in a part P, which is the thick part of the product, in the product space R.
Let's face each of them individually. The pressure plate 10 is
It is connected to a piston rod 16 of a pressure cylinder 14.15 fixed to the support plate 6 via a bracket 13, and each pressure pin 11.12 moves up and down by the action of the pressure cylinder 14.15.

Pressure pin 11. ．． The reference numeral 12 is made of a heat pipe, for example, as a thermally conductive material, and each pressure pin 11
．． An induction coil 17 as a heating means is installed on the upper outer periphery of 12.
．． 18 are arranged. and induction coil 17.1
By heating the upper part of the pressure pins 11 and 12 with 8,
Due to its thermal conductivity, the tips of the pressure pins 11 and 12 facing the product space R can be quickly heated.

Here, a predetermined temperature difference is provided between the pressure pins 11 and 12 so that the pressure pin 11 has a higher temperature.

In the local pressure casting apparatus configured in this way, molten metal M is supplied from a water heater (not shown) to the space above the plunger 7.
After guiding the molten metal M, the plunger 7 is moved upward to fill the product part space R with the molten metal M. Subsequently, the molten metal M by the plunger 7
Waiting for the completion of filling, the pressurizing cylinders 14 and 15 are activated simultaneously, and the pressurizing pins 11 and 12 heated by the induction coils 17 and 18 are moved downward, as shown in FIG. 11. Apply pressure at a predetermined pressure until the tip end surface of 12 is flush with the upper plane of the product space R.

At this time, especially in the thick part P1 far from the gate part 8, since the molten metal M is filled first, the solidification progresses relatively quickly, and in general, if the thick part P1 is pressurized at the same time as the thick part P1, the pressurization timing is I'm afraid I'll be late. However, since the pressure pin 11 itself is preheated to a higher temperature than the other pressure pin 12, this pressure pin 11
Due to the heat, the progress of solidification itself in the thick portion P is delayed. Therefore, even if the thick part P is pressurized by the pressure pin 11 at the same timing as the pressurizing timing of the pressure pin 12, the pressure can be applied at the optimal timing according to the progress of solidification of the thick part P1. You will be able to do this. As a result, the desired effects of the local pressure casting method can be fully obtained, and the occurrence of casting defects such as "sink holes" can be prevented.

Here, the above heating means includes induction coils 17 and 18.
It is also possible to use a heating means using gas instead, and the pressure pins 11 and 12 can also be used as push-out pins for taking out the product.

Effects of the Invention As described above, according to the present invention, by providing the heating means for heating the pressure pin that controls local pressure of the molten metal,
It is possible to substantially delay the progress of coagulation in the vicinity of the area to be pressed by the pressure pin. As a result, there is greater flexibility in the timing of applying pressure using the pressure pin, and there is no delay in the timing of applying pressure, especially in areas far away from the gate, making it possible to apply pressure at the optimal timing according to the progress of solidification. As a result, the occurrence of casting defects such as "sinkage cavities" can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the local pressure casting apparatus of the present invention, and is an explanatory diagram of the configuration before local pressurization, and FIG. 2 is a configuration explanatory diagram showing the state after local pressurization. 1. Mold, 7. Plunger, 8. Game]・Part, 1
1.12...Pressure pin! , 4.15... Pressure cylinder, ], 7.18... Induction coil as heating means, M
... Molten metal, R... Product department space.

Claims (1)

[Claims] (1) In a casting device that locally pressurizes the molten metal filled in the product space of a mold by a pressure pin whose tip faces the product space, the heating means for heating the pressure pin is provided. A local pressure casting device characterized by being provided with.