JPH04162951A - Locally pressurizing method in die casting method for aluminum alloy casting - Google Patents

Abstract

PURPOSE:To eliminate a casting product without developing seizure and galling by providing a sliding block inserting a core for locally pressurizing to die parting face between a movable die and a fixed die and retreating this sliding block along the die parting face before taking out the cast product. CONSTITUTION:The movable die 1 is fixed under pressurizing to the fixed die 2, and cavity 7 is formed and also, molten metal is pressed into the cavity with molten metal pressing-in device of a sleeve, etc., provided on the lower part of the movable die and the fixed die. The molten metal is filled up to excess thickness part 8 for pressurizing. Gas in the cavity is discharged to an external part from a gas venting slit 9. The core 4 for locally pressurizing is intruded into the excess thickness part for pressurizing so as to fill up unsolidified molten metal into shrinkage hole developed accompanied with solidification. Thereafter, the core 4 for locally pressurizing is retreated from the excess thickness part for pressurizing and successively, the movable die is retreated from the fixed die and an inclined pin 5 is retreated from an inserting hole 6 together with retreat of the movable die and the sliding block 3 is retreated from the upper face of the excess thickness part for pressurizing by the prescribed quantity. Thereafter, the casting product is taken out with an ejecting pin in the movable die.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a local pressing method in die casting of aluminum alloy castings.

[Conventional technology]

The die casting method is a highly productive casting method that can manufacture aluminum alloy cast products in large quantities with high precision.In addition, the die casting method is a highly productive casting method that can manufacture aluminum alloy casting products in large quantities with high precision. There is a problem that the particles are not discharged, but get caught up inside the cast product, become compressed, and remain, resulting in product defects. There is also the problem of cavities forming in thick-walled parts of cast products. To deal with these problems, bore-free die-casting, gas-free die-casting, or low-speed filling die-casting were developed to prevent gas entrainment, and die-casting combined with local pressure was developed to prevent cavities in thick-walled areas. The law was developed,
It is used alone or in combination with the former and latter.

[Problem to be solved by the invention]

By the way, the local pressurization in the above-mentioned local pressurization combined die casting method is performed by using a movable mold 15 and a fixed mold 16, as shown in FIG.
A sleeve 21 through which a local pressurizing core 20 can be inserted is provided above the pressurizing excess wall 19 provided along the upper mold dividing surface of the cavity 18 of the mold 17,
After the molten aluminum fills the cavity 18 and the pressurized excess wall 19, the local pressurizing core 20 is inserted into the pressurized excess wall so that the unsolidified molten metal fills the evacuation cavities that occur as solidification progresses. It is carried out by entering the 19th. With such a method of local pressurization, when applying local pressure, which dividing surface should the molten aluminum be inserted between the sleeve 21, the movable mold 15, and the fixed mold 16, and between the sleeve 21 and the core 20 for local pressurization? Also, there may be a slight accumulation of aluminum on the lower end surface of the local pressure core 20, and the lower end surface of the local pressure core 20 and the lower end surface of the sleeve 21 may not be flush with each other. , since the direction of insertion and deposition is a direction that intersects the direction of taking out the cast product from the cavity 18, it becomes difficult to take out the cast product smoothly when taking out the cast product from the cavity 18 after die casting.Furthermore, In order to avoid such troubles, it is necessary to frequently clean the deposits that have adhered to the inserted pad and the local pressure core 20, which impairs productivity.Furthermore, it is necessary to frequently clean the deposits that have adhered to the inserted pad and the local pressurizing core 20, which impairs productivity. Since the direction is parallel to the lower end surface of the local pressurizing core 20 and the lower end surface of the sleeve 21, these lower end surfaces are likely to seize and gall, and in order to prevent this, it is necessary to apply a mold release agent. As a result, the release agent accumulates significantly on the upper surface of the cast product or on the gas venting area, making it difficult to vent gas.

The present invention has been made in view of the above-mentioned problems, and its purpose is to prevent molten aluminum from being inserted between the sleeve and the local pressurizing core, Even if there is accumulation on the lower end surface of the core, the cast product can be taken out without any problem, and the cast product can be taken out without seizing or galling on the lower end surface of the local pressurizing core or sleeve. An object of the present invention is to provide a method for applying local pressure in die casting.

Means for Solving Problem C] In order to achieve the above object, the local pressurization method in the die casting method for aluminum alloy castings of the present invention is a local pressurization method in a mold having a movable mold and a fixed mold. hand,
A sliding block into which a core for local pressure is inserted is installed on the molding surfaces of the movable and fixed molds, and this sliding block is moved back along the molding surface before taking out the cast product after die casting. be.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a cross-sectional explanatory diagram of a local pressing structure to which the local pressing method in the die-casting method for aluminum alloy castings according to the present invention is applied, and FIG. FIG.

In the figure, 1 is a movable type, 2 is a fixed type, 3 is a sliding block, 4 is a core for local pressure provided on the sliding block 3,
5 is an inclined bottle, 6 is an insertion hole of the inclined bottle, 7 is a cavity, 8 is a pressurized extra wall portion, and 9 is a gas vent slit.

The sliding block 3 is provided so that it can be slid up and down along the mold dividing surfaces of the movable mold 1 and the fixed mold 2, so that the sliding block 3 is located on the lower surface or the upper part of the pressurized excess wall part 8, and is located at the center of the sliding block 3. In the hole IO drilled in the section, there is a local pressurizing core 4 that can be moved forward and backward by a drive device (not shown), or a sliding block 3 whose lower end surface is inserted.
It is provided flush with the lower end surface of.

Further, on both sides of the sliding block 3, an insertion hole 6 for an inclined bottle 5 is provided, which is bored through the fixed mold 2. By moving the inclined bottle 5 forward and backward within this insertion hole 6, the sliding block 3 can be moved. 3 is configured so that it can move up and down.

Die casting of an aluminum alloy casting is carried out as follows using a mold having the above-described local pressure structure.

First, by a conventional method, the movable mold 1 is pressurized and fixed to the fixed mold 2 to form the cavity 7, and the movable mold 1 and the fixed mold 2 are
The molten metal is press-fitted into the cavity 7 from below by a molten-metal injection device (not shown) such as a sleeve or plunger tip provided at the bottom of the cavity 7 . By this press-fitting, the molten metal rises inside the cavity 7 and is filled up to the pressurized excess wall portion 8 . At this time, the gas in the cavity 7 is discharged to the outside from the gas vent slit 9 by the pressurizing force accompanying the rise of the molten metal. Next, the local pressurizing core 4 is advanced into the pressurizing excess wall portion 8 so as to fill the unsolidified molten metal into the cavities generated as solidification progresses. After this, in order to take out the cast product, first, the local pressurizing core 4 is placed on the pressurizing excess wall part 8.
Retreat from within. Next, the movable mold 1 is retracted from the fixed mold 2, and as the movable mold 1 is retracted, the inclined bin 5 is inserted into the insertion hole 6.
This action causes the sliding block 3 to retreat a predetermined amount from the upper surface of the pressurized excess wall portion 8, and then the cast product is taken out by an extrusion bottle (not shown) provided in the movable mold 1.

In this way, when taking out a cast product, the sliding block 3
Since the local pressure core 4 is recessed by a predetermined amount from the upper surface of the pressure surplus portion 8, even if there is aluminum deposit on the lower end surface of the local pressure core 4, it will not become an obstacle. This retreat cuts or cleans the dividing surfaces of the sliding block 3, movable mold 1, and fixed mold 2, as well as the aluminum plate inserted between the sliding block 3 and the local pressure core 4, so that the movable mold 1. Removal of the cast product from 1 is performed smoothly. In addition, since there is no seizure or galling on the lower end surfaces of the local pressure core 4 and the sliding block 3, there is no need to use excess mold release agent. occlusion will also be reduced.

In fact, according to the above local pressurization method, the local pressurization core 4
The number of maintenance operations such as removing deposits was reduced by about half, and the number of blistering defects in products after heat treatment was reduced, improving productivity.

In the above embodiment, the sliding block 3 is driven by the inclined pin 5, but the present invention is not limited to this example, and the sliding block 3 may be driven by a hydraulic cylinder or the like.

〔Effect of the invention〕

As described above, according to the local pressurization method in the die-casting method for aluminum alloy castings according to the present invention, even if molten aluminum is inserted between the sliding block and the core for local pressurization, the aluminum Even if deposits are deposited on the lower end surface of the local pressure core, the cast product can be removed from the movable mold without any problem, and the lower end surface of the local pressure core and sliding block will not seize or become galled. It is possible to take out the cast products without having to remove them.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a local pressing structure to which the local pressing method in the die-casting method for aluminum alloy castings according to the present invention is applied, and FIG. FIG. 3 is a cross-sectional view of the prior art. l Movable type 2 Fixed type 3 Sliding block 4 Core for local pressure 5 Inclined bottle 6 Inclined bottle insertion hole 7 Cavity
8 Pressurized excess thickness 9 Gas vent slit lO hole Patent applicant Kobe Steel Co., Ltd. Representative Patent attorney Akira Kanemaru - Figure 1 Figure 2

Claims (1)

[Claims] (1) A method for applying local pressure in a mold having a movable mold and a fixed mold, in which a sliding block in which a core for local pressing is inserted is provided on the mold dividing surface of the movable mold and the fixed mold, and this sliding block is A method for applying local pressure in a die-casting method for aluminum alloy castings, characterized in that a moving block is moved back along a mold dividing surface before taking out a cast product after die-casting.