JPH07155896A - Metallic mold for high precision casting - Google Patents

Abstract

PURPOSE:To improve the positional precision of a core by inserting the core between an upper mold and a lower mold being vertically separatable and arranging a weight being vertically movable in the upper mold containing draw back molds to suppress the float-up of the core. CONSTITUTION:The cylindrical weight 7 is inserted so as to be vertically movable in holes penetrated in the draw back molds 2 and the lower surface of the weight 7 is brought into contact with core print parts of the inlet and the outlet part cores 5, 6. As a large diameter part at the upper part of the weight 7 is engaged with the step part in the hole, the projecting size to the lower part of the weight 7 is made to be the constant. The inlet and the outlet part cores 5, 6 intend to float up by pouring the molten metal from a sprue arranged in the lower mold 1, but the weights 7 are loaded to the inlet and the outlet part cores 5, 6 and the float-up is prevented and the cores can precisely be positioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting mold for producing a casting product, and more particularly, it is improved so that the core is accurately positioned to improve the casting accuracy.

[0002]

2. Description of the Related Art Generally, a mold used for casting is composed of an upper mold half and a lower mold half which are divided into upper and lower parts. When forming a hollow part, a core is placed at a position corresponding to a hole. Have been inserted. Further, there is also one in which a lateral mold that can be divided into left and right is sandwiched between an upper mold and a lower mold and incorporated as a part of either the upper mold or the lower mold.

For example, in the case of low pressure casting of a cylinder head made of aluminum alloy, as shown in FIG.
The mold 02 and the upper mold 03 are used. Lower mold 01 and upper mold 0
3 is arranged so that it can move up and down and can be divided.
Is sandwiched between a lower mold 01 and an upper mold 03, and can be moved in the left-right direction to be divided. Here, the template 02 is
It is held so as to be slidable in the lateral direction with respect to the upper mold 03, and integrally moves as a part of the upper mold 03.

In such a mold, a water jacket core 04 for forming a space for flowing the cooling water of the cylinder head, and an intake port core 05 for forming a passage for vaporized gasoline.
Also, an exhaust port core 06 for forming a flow path of exhaust gas is inserted. When casting, these cores 04,0
After 5,06 is set in the mold, the mold is closed and poured from a spout (not shown) of the lower mold 01, and after a certain period of time, the product is solidified and then released from the mold and taken out.

[0005]

Unlike the water jacket core 04, the above-mentioned intake / exhaust port cores 05 and 06 are supported in the mold in a cantilevered state, so that the positioning accuracy is unsatisfactory. There was a problem that the casting quality was insufficient and the casting quality was deteriorated.

That is, as shown in FIG. 3, the intake / exhaust port cores 05, 06 hold an elongated port core-shaped portion 07 for forming a flow path and a plurality of these port core-shaped portions 07. It is composed of a skirting board 08 of sardines.
The intake / exhaust port cores 05 and 06 are supported by the skirting board 08 in a cantilevered manner between the skirting board of the lower die 01 and the skirting board 02 and the skirting board, and the tip portion of the port core-shaped portion 07 burns. The chamber is positioned at the positioning portions (valve seats) 01a and 01b.

Here, in order to prevent the intake / exhaust port cores 05, 06 from being broken due to the effect of thermal expansion during casting, the skirting part 08 of the intake / exhaust port cores 05, 06 and the lower die 0.
An appropriate gap is provided in the up-down direction between the skirting board 1 and the mold 02 and the skirting board. Therefore, the intake / exhaust port core 05,0
Although No. 6 was accurately positioned in the front-back direction, it was not accurately positioned in the vertical direction. For this reason, the buoyancy generated during pouring, and also because it is pushed up by pouring from the spout provided in the lower mold 01, the intake / exhaust port cores 05 and 06 are lifted up, and the combustion chamber positioning portion 01a, The position of 01b and the port core-shaped portion 07 would be displaced.

At present, due to the high performance of the engine, the deviation between the valve seat and the port shape is ± 0.5 m including machining.
m is required, but if such a deviation occurs during casting, it becomes impossible to meet such a requirement. There is also a problem that a thin wall portion is formed between the intake / exhaust port cores 05 and 06 and the water jacket core 04. Therefore, conventionally, the skirting part 0 of the intake / exhaust port cores 05, 06 is
It is designed to make the gap between the skirting board of 8 and the lower mold 01 and the skirting board of the lower mold 02 and the skirting board as narrow as possible, but if it is too narrow, the core will break.

Further, as shown in FIG. 4, by increasing the length of the skirting board 08 of the intake / exhaust port cores 05, 06, and by adding an auxiliary skirting board 09 as shown in FIG. It is also considered to reduce the lifting of the exhaust ports 05 and 06, but there is a limit because the mold becomes large, and there is also a problem that the core is deformed when the core becomes large. The present invention has been made in view of the above prior art, and an object of the present invention is to provide a high-precision casting mold with improved casting quality by suppressing lifting of the core during pouring. .

[0010]

The structure of the present invention for achieving the above object is to insert a core between an upper mold and a lower mold which are vertically separable and to provide a vertically movable weight on the upper mold. And the core is pressed by the weight of the weight during pouring. Here, the upper mold may include a lateral mold that is separable to the left and right, and the weight may be provided on the lateral mold so as to be vertically movable.

[0011]

By properly pressing the core, which is about to float due to buoyancy during pouring, with the weight, the core can be accurately positioned without causing breakage of the core.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. One embodiment of the present invention is shown in FIG. The present embodiment is applied to a mold for casting an aluminum alloy cylinder head. That is, the mold is composed of a lower mold 1, a side mold 2, and an upper mold 3, and a plurality of cores 4, 5,
6 has been inserted.

The upper die 3 is located above the lower die 1 and can be moved vertically to be divided, and the side die 2 is sandwiched between the lower die 1 and the upper die 3 so as to extend in the left-right direction. It can be moved and divided. The side mold 2 is held so as to be slidable laterally with respect to the upper mold 3, and moves integrally as a part of the upper mold 3. The water jacket core 4 is a core for making a space for flowing the cooling water of the cylinder head, and the intake port core 5 is a core for making a passage for vaporized gasoline,
The exhaust port core 6 is a core for forming a flow path of exhaust gas.

Here, the intake / exhaust port cores 5 and 6 are elongated port core-shaped portions for forming flow paths, and skirting portions for holding a plurality of these port core-shaped portions 7. (See FIG. 3). Therefore, the intake / exhaust port cores 5 and 6 are supported by the skirting board in a cantilevered manner between the skirting board of the lower mold 1 and the side mold 2 and the skirting board, and the tip of the port core-shaped part is It is positioned on the positioning portions 1a and 1b of the combustion chamber. However, due to the effect of thermal expansion during casting,
In order to prevent the intake / exhaust port cores 5 and 6 from being broken, it is appropriate to vertically move between the skirting part 8 of the intake / exhaust port cores 5 and 6, the skirting board of the lower mold 1, the side mold 2 and the skirting board. There is a gap.

Further, in the invention, the weight 7 is provided for suppressing the lifting of the intake / exhaust port cores 5, 6 during pouring. That is, the cylindrical weight 7 is vertically movably inserted into the hole vertically penetrating the skirting board of the mold 2.
The lower surface of the weight 7 is in contact with the skirting portions of the intake / exhaust port cores 5 and 6. The upper portion of the weight 7 has a large diameter portion and is engaged with the step portion in the hole. Therefore, the downward protrusion amount of the weight 7 is limited to a constant value.

The material of the weight 7 is not particularly limited, but it is necessary to have a weight enough to suppress the lifting of the intake / exhaust port cores 5, 6. In order to suppress the lifting of the intake / exhaust port cores 5 and 6, it is conceivable to use springs or other elastic bodies, but this is not applicable because it easily deteriorates due to the heat effect during casting.

According to this embodiment having the above-mentioned structure, the intake / exhaust port cores 5 and 6 are likely to float due to the buoyancy at the time of pouring and the pouring from the spout provided in the lower mold 1. However, since the weight of the weight 7 is applied to the intake / exhaust port cores 5 and 6, the cores 5 and 6 are prevented from being lifted and the cores 5 and 6 can be accurately positioned. Therefore, precise casting can be performed without shifting the positions of the port core-shaped portions of the intake / exhaust port cores 5 and 6 and the positioning portions 1a and 1b of the combustion chamber.

The above embodiment is applied to the case where a cylinder head made of aluminum alloy is cast, so that it can contribute to the improvement of engine performance. The present invention is not limited to this, and is widely applied to prevent the core from rising and improve the positioning accuracy. Further, although the side mold 2 is used in the above embodiment, the side mold 2 is not always necessary, and the weight 7 may be directly provided on the upper mold 1.

The appropriate vertical gap between the cores 5 and 6 and the lower mold 1 and the side mold 2 is different from the conventional meaning. Conventionally, it has been desired to make the core 5 as narrow as possible in order to prevent the core 5 from being displaced. However, in the present invention, the weight 7 reliably prevents the core 5 from being displaced. There is no. Rather, even if the accuracy of the cores 5 and 6 is rough, the accuracy of the product is not deteriorated, so that it is possible to make the clearance larger than the conventional appropriate clearance.

Next, a casting machine to which the high precision casting mold of the above embodiment is applied will be described with reference to FIG. Figure 6
As shown in, a heating heater 11 is attached to a furnace body 10 having a crucible 9 filled with a molten metal 8, and a float 12 is vertically movably inserted into a molten metal inlet.
A mold including a lower mold 1, a side mold 2, and an upper mold 3 is held by a frame 13 above the furnace main body 10, and is provided in the lower mold 1 and a hot water outlet provided on the upper surface of the furnace main body 10. Tagate 1
c communicates.

Therefore, by moving the float 12 up and down, the pressure of the molten metal 8 rises, and the sprue 1c of the lower die 1
The molten metal is poured into the mold from. Since the water jacket core 4 and the intake / exhaust port cores 5 and 6 are inserted into the mold and the intake / exhaust port cores 5 and 6 are pressed by the weight 7, it is possible to suck the molten metal by pouring the molten metal. The exhaust port cores 5 and 6 do not float up.

A vertically moving rod 14 arranged vertically is connected to the upper mold 3, and the side mold 2 can be vertically moved together with the upper mold 3 by an operation from a driving source (not shown). . Also, in the raised position,
Is provided with a side mold cylinder 15 which can be engaged with the side mold 2 and moved to the left and right.

[0023]

As described above in detail based on the embodiments, the present invention surely suppresses the lifting of the core during pouring by the weight, so that the core is prevented from being broken,
It is possible to improve the positioning accuracy of the core and the casting quality.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a high precision casting mold according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional casting mold.

FIG. 3 is a perspective view of an intake / exhaust port.

FIG. 4 is a perspective view of an intake / exhaust port having an elongated skirting portion.

FIG. 5 is a perspective view of an intake / exhaust port provided with an auxiliary skirting board.

FIG. 6 is a configuration diagram of a casting machine using a high precision casting mold according to an embodiment of the present invention.

[Explanation of symbols]

 1,01 Lower mold 1a, 1b Combustion chamber positioning part 1c Gate 2,02 Side mold 3,03 Upper mold 4,04 Water jacket core 5,05 Intake port core 6,06 Exhaust port core 7 Weight 8 Molten metal 9 crucible 10 furnace body 11 heating heater 12 float 13 frame 14 lifting drive rod 15 close-up cylinder 07 port core shape part 08 skirting part 09 auxiliary skirting part

Claims (2)

[Claims] 1. A core is inserted between an upper mold and a lower mold that are vertically separable, and a vertically movable weight is provided on the upper mold, and the core is pressed by the weight of the weight when pouring. A high-precision casting mold characterized by being attached. 2. The high precision casting mold according to claim 1, wherein the upper mold includes a laterally separable lateral mold, and the weight is provided on the lateral mold so as to be vertically movable.