JPH02117761A - Cooling method for casting die - Google Patents

Abstract

PURPOSE:To control a cooling speed of a die extending over a long period of time without causing a corrosion by providing a cavity on a part which becomes the back of the die engraving surface of the die, containing a hollow cooling block therein and allowing the cooling block to abut or separate on or from the inside surface of the die, while feeding cooling water to the block at the time of casting. CONSTITUTION:At the time of casting, a core 8 is held in the upper die 1 in a die open state, slide cores 5, 5 are moved, and also, the upper die 1 is allowed to descend and set to a die closed state. In this case, a cooling block 13 is in a descend position, and its upper face 13a and side face 13b are in a state that they are separated from the inside surface of the lower die liner 4. Subsequently, a molten metal is injected to a cavity 6 through a runner 7, and as soon as filling to the cavity 6 is completed, pressurization is executed. Next, the cooling block 13 is allowed to ascend by a cylinder 14, and its upper face 13a and side face 13b are allowed to abut on the inside surface of the lower die liner 4. To the inside of the cooling block 13, cooling water is supplied from a cooling water supply device 15, and the lower die liner is quenced, and by following it up, a cast part is also quenched. Accordingly, the die is opened in a short time and the cast part can be taken out of the die.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for cooling a casting mold.

(Prior art) In mold casting, in order to control the solidification rate and cooling rate after solidification, water holes are drilled in the mold and cooling water is fed into these from a cooling water supply device. 1. Forcibly cooling the mold is often done. By the way, 1. For example, in high-pressure casting, the molten metal is pressurized at the end of filling the mold cavity, but in such a case, the method of directly cooling the mold with cooling water will not solidify the metal. The problem progressed rapidly, and there was a risk that the pressurized filling of the molten metal would be incomplete.

Therefore, conventionally, as shown in Japanese Patent Application Laid-Open No. 62-142080, a measure has been taken to insert a cooling delay pipe into the water passage hole to reduce the transfer of heat to the cooling water and delay solidification. was there. however,
According to such a measure, the Fl product is slowly cooled even after the solidification is completed, which lengthens the cycle time and impedes productivity.

In view of the above background, conventionally, as shown in FIG. The detected mold temperature signal is taken into the control device 27, and the control device 2
A cooling method in which the switching valve 25 is opened and closed as appropriate based on commands from the mold 7 to control the cooling rate of the mold 21 has been established and has already been put into practical use. According to this method, for example, when filling molten metal, the switching valve 25 is closed to cut off the supply of cooling water to the water passage hole 22, and at the same time as solidification is completed, the switching valve 25 is opened to supply cooling water to the water passage hole 22. This makes it possible to carry out the following operations, and the above-mentioned problems related to cooling before and after solidification can be solved together, and the applicability to high-pressure casting can be significantly increased. In addition, in the same figure, 28 is a cavity which becomes a casting space,
Reference numerals 29 each represent a tank for storing the cooling water returned from the water passage hole 22.

(Problem to be Solved by the Invention) However, according to the casting mold cooling method using the switching valve 25, the inner surface of the water passage hole 22 comes into contact with air every time the switching valve 25 is closed, and as a result of repeated Corrosion occurs on the inner surface of the hole, and due to this corrosion, the cooling capacity may decrease, and in some cases, corrosion fatigue may progress, leading to early failure of the mold 21, which poses a problem in terms of reliability. By the way, it happened.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to provide a method for cooling a casting mold that can stably control the cooling rate of the mold over a long period of time. There is a particular thing.

(Means for Solving the Problems) In order to solve the second problem, the present invention provides a cavity in the rear part of the die engraving surface of the mold, and houses a hollow cooling block in this cavity. The gist of the present invention is that cooling water is fed into the cooling block during casting, and the cooling block is brought into contact with or separated from the inner surface of the mold at a predetermined timing.

In the present invention, the part of the mold in which the cavity is provided is not particularly limited, and a desired part can be selected depending on the size and shape of the cast product, the casting method, etc. Further, the number of cavities is also arbitrary, and they can be provided at multiple locations in the mold.

When a nest is used as the mold, the cavity is provided in the nest.

Further, in the present invention, the cooling block is desirably made of a material with good thermal conductivity, such as copper, and is movably disposed within the cavity and supported by an actuator, The timing of operation of the cooling block, which allows the state of contact with the inner surface of the mold and the state of separation from the inner surface of the mold to be arbitrarily selected, is not particularly limited. For example, when applied to high pressure casting,
It is sufficient to keep it away from the inside of the mold at all times, and bring it into contact with the inside of the mold at the same time as the pressurization is completed after filling the mold cavity with molten metal. In this case, the movement of the cooling block is controlled by the casting process. It can be controlled by time management within the cycle or mold temperature management.

(Function) In the method for cooling the casting mold configured as described above,
The cooling rate of the mold can be arbitrarily controlled by bringing the cooling block into contact with the inner surface of the mold. Moreover, by using cooling blow and glue, the mold does not come into direct contact with cooling water, which prevents corrosion of the mold.

(Example) An example of the present invention will be described below based on the accompanying drawings.

In FIG. 1, 1 is an upper mold, and 2 is a lower mold. The upper mold 1 is supported by a driving means (path shown in the figure) and can be freely moved in a downward direction L.

The upper mold 1 and the lower mold 2 face each other at the upper and lower mold 3.
The lower mold inserts 4 are respectively attached, and a slide core 5.5 is attached to the upper mold l so as to be horizontally slidable.

Each slide core 5, 5 moves forward from the left and right in the figure by a drive means (path shown), and cooperates with the upper mold insert 3 and the lower mold insert 4 when the upper mold 1 and the lower mold 2 are in a closed state. One casting space (cavity) 6 is formed. Also F type insert 4
is provided with a runner 7 and a spout (path shown) that communicate with the cavity 6, and from a separately provided injection cylinder (path shown) flows into the cavity 8 through the spout and runner 7. Molten metal is injected.

The water mold is used for casting cylinder blocks, and the cavity 6 houses a collapsible core 8 for forming a water jacket.

A cavity 12 is formed in the lower die insert 4 at the back of the die engraving surface 11, and a hollow copper cooling block 13 is housed inside the cavity 12 so as to be able to slide vertically. There is. The opening end of the cavity 12 is closed by the lower mold 2 to form a closed space, and the lower mold 2 faces the cavity 12.
A cylinder 14 for supporting and driving the cooling block 13 is fixedly installed on the top. The cooling block 13 has an upper surface 13a and a side surface 13b shaped to follow the cross-sectional shape of the cavity 12, and is moved up and down by the operation of the cylinder 14, so that the upper surface 13a and the side surface 13b are shaped to follow the cross-sectional shape of the cavity 12. It can be brought into contact with or separated from the inner surface as desired. 15 is a cooling water supply device, and 16 is a tank, each of which is installed outside the mold and connected to the cooling block 13 through piping 17 and piping 18.

Hereinafter, a mold cooling method applied to the casting mold configured as described above will be explained.

During casting, first, the core 8 is placed in the upper mold 1 in an open state, and then the slide cores 5, 5 are moved and the upper mold 1 is lowered to bring the mold into the closed state as shown. At this time, the cooling block 13 is in the lowered position, and its upper surface 13a and side surface 13b are separated from the inner surface of the lower mold insert 4 as shown in FIG. Then, pass through the pouring spout and runner 7 into cavity B.
The lower mold insert 4 injects the molten metal into the cooling block 1 and applies pressure at the same time as the filling of the molten metal into the cavity 8 is completed.
Due to the distance of 3, the heat performance is small, and as the molten metal is filled, the temperature is increased and maintained in a short time. Therefore, during the filling of the molten metal, the progress of solidification is suppressed, allowing effective pressurization.

Next, after the pressurized filling is completed, the cylinder 14 is actuated, for example, by time management or temperature control of the lower mold insert 4, the cooling block 13 is raised, and its upper surface 13a and side surface 13b are placed in the lower mold insert. Bring it into contact with the inner surface of 4. Cooling water is supplied into the cooling block 13 from a cooling water supply device 15, and the lower mold insert 4 is rapidly cooled by contact with the cooling block 13, and the cast product after solidification is also rapidly cooled. be done. As a result, it becomes possible to open the mold and take out the cast product from the mold in a short time, improving productivity. After that, the cooling block 13 is used for time management or lower mold insert 4.
As a result, the temperature of the lower mold insert 4 rises due to its own heat, and waste of energy in continuous operations is suppressed as much as possible.

Note that the above example shows the case where it is applied to high-pressure casting, but the mold is divided as appropriate according to the cavity shape, the cooling block is installed at the desired location, and the cooling block is placed in contact with the inner surface of the mold. By controlling the timing of separation, the solidification rate of each part of the cavity can be controlled.

For example, it becomes possible to realize directional solidification and produce high-quality cast products.

(Effects of the Invention) As described above in detail, according to the method for cooling a casting mold according to the present invention, the cooling block through which cooling water flows is brought into contact with and separated from the inner surface of the mold, thereby molding the mold. Since the cooling rate of the mold is controlled, it becomes possible to permanently and stably control the cooling rate of the mold without causing corrosion of the mold, which has an effect that greatly contributes to improving reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a casting mold to which the cooling method of the present invention is applied, and FIG. 2 is a sectional view of a casting mold to which the conventional cooling method is applied. 1... Upper mold, 2... Lower mold 3...
Upper mold insert, 4...Lower mold insert 5...Slide core, 11...Die engraving surface 12...Cavity,
13...Cooling blow, ri15...
Cooling water supply device, 16...Tank patent applicant Toyota Motor Corporation

Claims (1)

[Claims] (1) A cavity is provided in the rear part of the die engraving surface of the mold, and a hollow cooling block is stored in this cavity,
A method for cooling a casting mold, comprising feeding cooling water into the cooling block during casting, and bringing the cooling block into contact with or away from the inner surface of the mold at a predetermined timing.