JPH091313A - Pin for hole as cast in aluminum alloy casting and method for controlling temperature thereof - Google Patents

Abstract

PURPOSE: To prevent the development of shrinkage cavity and leakage due to pressure in a die and to improve the yield of a product by setting a thermocouple into a pin for a hole as cast and controlling a die temp. with this detected temp., at the time of forming a bolt hole in the cast product with the pin for the hole as cast. CONSTITUTION: The die is composed of a fixed die 1 and a movable die 5 and a formed hole 4 of a cavity 3 for the bolt hole is recessed in the cavity 2 of the fixed die 1, and an insert 7 is arranged at the position corresponding to the formed hole 4 in the movable die 5. The insert 7 has a constitution of arranging the pin 20 for a hole as cast forming the cavity 3 for the bolt hole inserted into the formed hole 4, and a cooling water pipe 32 and the thermocouple 30 in the inner part of the pin 20. The die clamping is executed and a core pin forming tube part of the pin 20 is inserted into the formed hole 4 and also, water is passed through a cooling passage and molten metal is poured into the cavities 2, 3. At this time, the temps. of the dies 1, 5 after pouring the molten metal are monitored with the thermocouple 30 and the water flowing rate from a water supplying joint 38 is controlled while comparing the monitored value with the set temp. to execute the die temp. control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting pin for forming a blind hole, for example, in a die for casting an aluminum alloy material, and a temperature control method therefor.

[0002]

2. Description of the Related Art Conventionally, for example, in die casting for casting an aluminum alloy material of this type, blind hole bolt holes are formed in a cast product. For example, as shown in FIG. Is formed with a molding hole 4 having a draft of the cavity 3 for the bolt hole, and the movable mold 5
The main mold 6 is provided with an insert 7, and the insert 7 is provided at a position corresponding to the forming hole 4 and the insert 7
A casting pin 8 for molding the cavity 3 for the bolt hole with the molding hole 4 is disposed so that it can be inserted and removed.

The casting pin 8 is formed with a molding pipe portion 9 on the tip end side thereof, which has a draft so that it can be inserted into and removed from the molding hole 4, and has a hollow portion 10 for supplying cooling water therein. A large-diameter water supply pipe portion 11 is formed continuously with the pipe portion 9 on the side of the insert 7, and a square block-shaped pin having a return hollow portion 13 communicating with the hollow portion 10 at the base portion of the water supply pipe portion 11. A holding portion 12 is formed, a return hole 14 is opened in the pin holding portion 12, and a drain pipe is connected to the return hole 14. The cooling water pipe 15 is inserted from the pin holding portion 12 side into the cast pin 8 thus formed, and the tip of the cooling water pipe 15 faces the tip of the molding pipe portion 9 with a predetermined space. . In this way, when the movable mold 5 having the casting pin 8 that has been inserted through the cooling water pipe 15 is moved to match the fixed mold 1, the casting pin 8 is inserted into the molding hole 4,
Bolt hole cavities 3 continuous with the cavities 2 are formed between them.

With the molds fitted together, cooling water is passed through a cooling passage (not shown) formed in the molds 1 and 5 so that the molds 1 and 5 are
5 is cooled substantially uniformly, and cooling water is also passed through the casting pin 8. In this state, the molten metal is injected from the sprue, and the injected molten metal is solidified sequentially from the cavity 2 part farthest from the sprue toward the sprue to form a cast product.

[0005]

However, the bolt hole formed by the casting pin 8 is located on the outer peripheral portion of the molded product, and therefore the temperature control of the entire mold is controlled by the temperature of the total discharged water. Although it can be controlled by control, there is no direct temperature control in the details, especially in the molded part of the bolt hole that is molded on the outer periphery of the cast product, so if the solidification time is long, the threaded surface However, there is a problem in that a shrinkage cavity is generated in the screw, resulting in defective screw forming, and seizure and pressure leakage. The present invention is made to solve the above-mentioned conventional problems, and provides a casting pin and a temperature control method capable of sufficiently controlling the temperature of a mold and improving the product yield. That is the purpose.

[0006]

SUMMARY OF THE INVENTION In order to solve the above technical problems, the present invention uses a fixed mold and a movable mold to form a bolt hole cavity in a cast product and a bolt hole by a casting pin having a cooling water pipe inside. In the casting to be formed, a thermocouple installed inside the casting pin, a temperature controller that continuously measures the mold temperature via the thermocouple, and a temperature controller that receives the mold temperature and inputs the temperature. The temperature control method of the casting pin in the aluminum alloy casting, which comprises a die temperature control device for controlling the water supply from the cooling water pipe in multiple stages compared with the die temperature data, and the casting pin The thermocouple installed inside is fixed with its temperature measuring contact to the tip of the core pin by velor metal, and the reference end is led out from the hole penetrating the connecting spacer of the cast pin and By Velometal It is sealed by pins punching cast and connectable to the external monitor.

[0007]

With the above construction, the temperature of the solidification process of the bolt hole portion formed in the peripheral portion of the cast product can be sufficiently controlled, shrinkage cavities can be prevented, and pressure leakage can be prevented. be able to.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a die-cast pin 8 in a die casting machine.
2 is a sectional view of a portion provided with a fixed mold 1 and a movable mold 5. The fixed mold 1 is provided with a draft of a bolt hole cavity 3 in its cavity 2 as in the conventional case. The molding hole 4 has a recess, and the movable mold 5 is provided with a nest 7 at a position corresponding to the molding hole 4 as in the conventional case.
A casting pin 20 for forming the bolt hole cavity 3 by being inserted into the molding hole 4 is provided. The casting pin 20 includes a core pin 21, a connecting spacer 26, and a cooling water pipe 32.
And a thermocouple 30.

As shown in FIG. 2, this core pin 21 has a draft in the outer peripheral portion and a hollow portion 24 in the inside, as shown in FIG.
And a water supply pipe 23. The predetermined length of the molding pipe 22 is projected from the mating surface 7a of the insert 7 by a predetermined length so that the molding pipe 22 can be inserted into the molding hole 4. It is provided so as to form a cavity 3 for a bolt hole with the molding hole 4. In addition, a square block-shaped pin holding portion 25 that doubles as a connecting portion that opens to the main mold 6 is formed at the base of the water supply pipe portion 23. The core pin 21 thus provided is attached to the insert 7, and the core pin 21 is continuously connected to the connecting spacer 26 having a cylindrical shape and a predetermined length.

As shown in FIG. 3, the connecting spacer 26 is connected to the core pin 21 through a joint member 27 which is watertightly fitted and connected to a pin holding portion 25 formed at the base of the core pin 21 on the tip side thereof. A pipe material 28 having an anticorrosive property is fitted to the inner diameter side of the connecting spacer 26 to form a double structure, and the connecting spacer 26 is fixed to the main mold 6 via a set screw member 29. It is provided in.
A thermocouple 30 is attached to the core pin 21 to which the connecting spacer 26 is connected in this way.

The thermocouple 30 is attached to the tip side of the molding tube portion 22 of the core pin 21, and the thermocouple 30 is inserted into the core pin 21 and the temperature measuring contact 30 thereof is provided.
As shown in FIG. 3, a is fixed to the tip of the molded pipe portion 22 by a kind of heat insulating material, velometal 31, which is a cold welding material for repair, and is a mixture of a base agent and an activator. The thermocouple 30 has a melting point of about 300 ° C. and a hardness of about 98 that of duralumin having a Rockwell hardness of about 98. The thermocouple 30 is a pipe member of the connecting spacer 26. 28 is drawn out from a hole 28a penetrating at a predetermined position of 28,
The hole 28a is sealed with velometal, and the reference end of the thermocouple 30 is connected to, for example, a temperature controller 39. As described above, the casting pin 20 having the thermocouple 30 as the interior has a cooling water pipe 3
2 has been inserted.

As shown in FIG. 1, the cooling water pipe 32 is composed of a water supply pipe 33 and a nozzle portion 34 provided on the tip end side thereof and inserted into the molded pipe portion 22 of the core pin 21 to eject cooling water. The water supply pipe 33 is formed with a connection pipe portion 35 projecting from the main mold 6 by a predetermined length, and with the cooling water pipe 32 inserted in the casting pin 20, there is a predetermined space on the outer periphery thereof. A condensate passage 36 is formed. Further, a drain joint 37 that communicates with the condensate passage 36 and drains the cooling water and a water supply joint 38 that communicates with the cooling water pipe 32 are attached to the connection pipe portion 35.

Cooling water is passed through the cooling water pipe 32 to the casting pin 20 provided in this way. As shown in FIG. 4, the casting pin 20 detected by the thermocouple 30 incorporated therein. The temperature of the part, that is, the temperature of the mold is detected by the thermocouple 30 and recorded in the temperature controller 39, and the detected temperature is compared with the mold temperature data set in the mold temperature controller 40. The cooling water from the water supply joint 38 is provided to control the water supply in multiple stages.

In the molding dies 1 and 5 constructed as described above, in the casting dies 20 in the movable dies 5 having the casting dies 20 forming the screw forming portion and the fixed dies 1 having the forming holes 4. The cooling water pipe 32 is arranged in the inner wall of the casting pin 20, and the thermocouple 30 is arranged in the casting pin 20. Therefore, by moving the movable mold 5 with respect to the fixed mold 1 and aligning the molds, the molding pipe portion 22 of the core pin 21 of the casting pin 20 is inserted into the molding hole 4, and both molds 1, 5 Cooling water is passed through the cooling passage of the. As the supply of each cooling water, water having a normal water temperature of about 20 ° C. is passed. In this state, the molten metal is poured from the sprue.

By this pouring, the cavity 2 and the bolt hole cavity 3 are filled with the molten metal, and heat is transferred between the molten metal and the molds 1 and 5 in the solidification process of the molten metal. This solidification process generally solidifies from the peripheral side of the cavity 2 toward the sprue, but in the cavity 2 having the bolt hole cavity 3 for forming the bolt hole, the cooling process is a normal cooling process. Although a process different from the process is followed, in this example, the mold temperature is constantly grasped because the mold pin 20 is internally provided with the thermocouple 30 to constantly measure the mold temperature. When the temperature of the mold is high, the temperature of the mold is compared with the mold temperature data set in the mold temperature control device 40 via the temperature controller 39 to increase or decrease the water flow from the water supply joint 38. hand,
Since it is configured to control the temperature of the main part of the product, it is possible to prevent the occurrence of shrinkage cavities and the like, and to prevent pressure leakage due to the mold temperature,
The yield of cast products can be improved.

[0016]

As described above, according to the present invention, the mold temperature is constantly measured by incorporating the thermocouple in the die-cast pin as described above.
If the mold is hot, it is compared with the mold temperature data set in the mold temperature controller via the temperature controller to increase or decrease the water flow from the water supply joint to control the temperature of the main part of the product. With this configuration, it is possible to prevent shrinkage cavities and the like from occurring and prevent pressure leakage due to mold temperature, thus improving the yield of cast products.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cast pin portion in a die casting mold.

FIG. 2 is an attachment state diagram of a core pin.

FIG. 3 is a connection diagram of a core pin and a connection spacer.

FIG. 4 is a cooling control diagram of a cast pin.

FIG. 5 is a view of a conventional die-cast pin.

[Explanation of symbols]

 1 Fixed Mold 2 Cavity 3 Bolt Hole Cavity 4 Molding Hole 5 Movable Mold 6 Main Mold 7 Nest 20 Casting Pin 21 Core Pin 22 Molded Pipe 23 Water Supply Pipe 25 Pin Holding 26 Connection Spacer 28 Pipe Material 30 Thermocouple 30a Temperature Measuring Contact 31 Velo Metal 32 Cooling Water Pipe 35 Connection Pipe 37 Drain Joint 38 Water Supply Joint 39 Temperature Controller 40 Mold Temperature Control Device

Claims (2)

[Claims] 1. A thermocouple installed in a casting pin in a casting in which a bolt hole is formed in a cast product by a fixed die and a movable die and a casting pin in which a cooling water pipe is provided. And a temperature controller that continuously measures the mold temperature via the thermocouple, and compares the mold temperature data received by the temperature controller with the mold temperature to pass water from the cooling water pipe. A method for controlling the temperature of a casting pin in aluminum alloy casting, which comprises a mold temperature control device for controlling water supply in multiple stages. 2. The thermocouple installed in the cast pin comprises:
The temperature measuring contact is fixed to the tip of the core pin with velor metal, the reference end is led out from the hole penetrating the connecting spacer of the casting pin, and the hole is sealed with velor metal to monitor externally. Casting pin for aluminum alloy casting that can be connected to.