JP2010188412A - Casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casting apparatus which can detect the period of the completion of feed of a molten metal without delay, and can suitably switch the cooling modes of a mold. <P>SOLUTION: The casting apparatus is equipped with: a mold 2 provided with a cavity 2c receiving a molten metal and a cooling flow passage; a molten metal feeding device feeding the molten metal to the cavity 2; a refrigerant feeding device flowing a fluid for cooling to the cooling flow passage; a temperature sensor measuring the temperature of the mold; a molten metal arrival sensor 22 detecting the completion of the feed of the molten metal to the cavity 2c; a first control part performing switching the refrigerant feeding device between the two cooling modes with different cooling efficiency from each other on the basis of a molten metal arrival signal detected by the molten metal arrival sensor 22; and a second control part controlling the cooling state in each cooling mode on the basis of the temperature measured value detected by the temperature sensor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a mold having a cavity for receiving a molten metal and a cooling flow path through which a cooling fluid passes, a hot water supply apparatus for supplying the molten metal to the cavity, a temperature sensor for measuring the temperature of the mold, and the temperature The present invention relates to a casting apparatus including a refrigerant supply device that causes a cooling fluid to flow in the cooling flow path based on a temperature measurement value detected by a sensor.

  As prior art document information related to this type of casting apparatus, there is Patent Document 1 shown below. The casting apparatus described in Patent Document 1 includes a switching unit that switches between a strong cooling mode in which water flows through the cooling channel and a weak cooling mode in which air flows through the cooling channel. Based on the mold temperature detected by the temperature sensor located close to the cavity, the hot water supply time of the molten metal (molten metal) and the solidification time after hot water supply are discriminated. Is configured to flow water with high cooling efficiency so that proper solidification can be obtained in a short time, and to flow air with low cooling efficiency so that the mold does not get too cold during the solidification time.

JP-A-7-241647 (paragraph 0010, FIG. 1)

  However, in the case of the casting apparatus described in Patent Document 1, there is a time lag from when the hot water supply to the cavity is completed until the heat of the molten metal is detected by being detected by the temperature sensor disposed in the vicinity of the cavity. For this reason, it has been difficult to accurately detect the timing of completion of the molten metal supply. Therefore, since it tends to be delayed to start the cooling in the strong cooling mode, there is a possibility that the mold may be burnt, or a time required for solidification becomes long.

  An object of the present invention is to provide a casting apparatus that can detect the time of completion of hot water supply without delay and can appropriately switch the cooling mode of the mold based on the detection in view of the problems found in the prior art described above. There is to do.

The casting apparatus according to the present invention is
A mold having a cavity for receiving molten metal and a cooling flow path through which a cooling fluid passes,
A hot water supply device for supplying molten metal to the cavity;
A refrigerant supply device for flowing the cooling fluid through the cooling flow path;
A temperature sensor for measuring the temperature of the mold,
A hot water sensor for detecting completion of hot water supply to the cavity by the hot water supply device;
A first control unit that switches the refrigerant supply device between two cooling modes having different cooling efficiencies based on a hot water signal detected by the hot water sensor, and a temperature measurement value detected by the temperature sensor. And a second control unit that controls a cooling state in each of the cooling modes.

  That is, in the casting apparatus according to the present invention, the control device recognizes the completion of the hot water supply to the cavity without a time lag based on the molten metal signal detected by the molten metal sensor, and cools the refrigerant supply device with high cooling efficiency. Since the mode can be switched, problems such as burning of the mold due to overheating of the mold temperature and a long time required for solidification are suppressed.

Another characteristic configuration of the control device according to the present invention includes an electric circuit in which the molten metal sensor is closed by the conductive molten metal supplied to the mold, and an energization sensor that electrically detects opening and closing of the electric circuit. And
The first control unit is configured to switch the refrigerant supply device from the first cooling mode to the second cooling mode having a lower cooling efficiency based on a release signal of the molded product detected by the hot water sensor. .

According to this configuration, the hot water sensor is realized by a simple and inexpensive mechanism including an electric circuit that is closed by the molten metal supplied to the mold and an energization sensor that electrically detects opening and closing of the electric circuit. Can do.
Further, according to the above configuration, the control device sets the refrigerant supply device to the second cooling mode having a lower cooling efficiency based on a signal generated when the solidified molten metal is separated from the molten metal sensor and the electric circuit is opened. Can be returned. Therefore, by reducing the cooling efficiency by the refrigerant supply device without delaying the timing at which the solidified molded product is removed from the mold, it is possible to prevent the mold from being overcooled and defects in the molded product due to the same supercooling.

  Another characteristic configuration of the control device according to the present invention is that the hot water sensor and the temperature sensor are attached to a common sensor body.

  According to this configuration, it is possible to reduce the installation space for the sensor required in the mold, and it is possible to select the installation location of the sensor in the mold more freely.

  Another characteristic configuration of the control device according to the present invention is that the temperature sensor includes a cylindrical sensor body attached to the mold so that a closed tip is exposed on the inner wall surface of the cavity, and the sensor body. An exposed sheath thermocouple inserted into the sensor body, and a seal member that seals the rear end of the sensor body in a state where the exposed sheath thermocouple is confined in the sensor body.

  According to this configuration, an exposed thermocouple using an exposed thermocouple with excellent temperature detection sensitivity is installed so that the sensor body containing the exposed thermocouple is exposed on the inner wall surface of the cavity. The thermal contact is arranged at a position separated from the inner wall surface of the cavity or the molten metal only by the thin wall surface of the sensor body. Therefore, the temperature at a location very close to the molten metal filled in the mold can be measured quickly, so that ideal temperature control capable of maintaining a high quality of the molded product can be performed. In addition, the mold is subject to abrupt temperature changes due to repeated filling and unloading of the molten metal, so condensation tends to occur especially on the outer periphery of the mold. According to this configuration, cooling and the rear end of the sensor body are sealed. Therefore, there is no possibility of moisture entering from the hole of the sheath or the boundary between the sheath of the exposed thermocouple and the sensor body and damaging the thermal contact or the strand of the exposed thermocouple.

It is the schematic which shows the whole casting apparatus. It is an enlarged view which shows a metal mold | die sensor. It is an enlarged view which shows the front-end | tip part and rear-end part of a temperature sensor. It is a block diagram which shows the structure of a control unit. It is explanatory drawing which shows the relationship between a casting process and cooling mode. It is a figure which shows the temperature control routine by a 1st control part.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated, referring drawings.
A casting apparatus 100 shown in FIG. 1 includes a mold 2 having a fixed mold 2a and a movable mold 2b, and a hot water supply apparatus 3 for supplying a molten metal such as an aluminum alloy to a cavity 2c of the mold 2. The movable mold 2b is supported by an attaching / detaching device (not shown) so as to be switchable between a casting position in close contact with the fixed mold 2a and a mold release position separated from the fixed mold 2a.

The hot water supply device 3 includes a hot water supply sleeve 4 attached to a part of the fixed mold 2 a, a hot water supply container (not shown) made of a ladle for pouring molten metal from a hot water supply port 4 a provided in the hot water supply sleeve 4, and a hot water supply sleeve 4. And a plunger 6 for pushing the poured molten metal into the cavity 2c. The plunger 6 is reciprocated by a hydraulic cylinder 7.
The mold 2 is provided with an eject pin 8 for extruding a molded product from the movable mold 2b switched to the mold release position after the molten metal is solidified.
The movable mold 2b is provided with an overflow part 2d disposed above the cavity 2c, and the upper end of the overflow part 2d communicates with a gas vent hole G formed between the fixed mold 2a and the movable mold 2b. ing.

(Cooling system)
A cooling channel 9 for flowing a cooling fluid for cooling the mold 2 is formed in the fixed mold 2a and the movable mold 2b. The cooling flow path 9 is configured by a tubular path or the like that extends from the fluid inlet 9a into the mold 2 and extends toward the vicinity of the cavity 2c and reaches the fluid outlet 9b through a flow path surrounding the cavity 2c.
A water supply pipe 10 and an air supply pipe 11 are simultaneously connected to a cooling pipe 9 c that reaches the fluid inlet 9 a of the cooling flow path 9. The water supply pipe 10 constitutes a part of a refrigerant supply device for flowing water as a cooling fluid to the cooling flow path 9, and the air supply pipe 11 serves as a part of the refrigerant supply device for flowing air as a cooling fluid to the cooling flow path 9. Eggplant.

  The water supply pipe 10 is provided with a pump 15 capable of pumping water from the water source 14 to the cooling pipe 9c and a first electromagnetic valve V1 for opening and closing the water supply pipe 10 on the downstream side of the pump 15 as a first refrigerant supply device. It has been. The pump 15 is operated by a motor M1 whose rotation speed is variable by an inverter 16.

The air supply pipe 11 is provided with a compressor 18 capable of pressure-feeding cooling air to the cooling pipe 9c and a second electromagnetic valve V2 for opening and closing the air supply pipe 11 on the downstream side of the compressor 18 as a second refrigerant supply device. It has been.
A part of the cooling pipe 9c is provided with a first pressure sensor 19a that measures the pressure of the fluid immediately before being supplied to the cooling flow path 9. Further, a pressure regulating valve 20 capable of adjusting the pressure of the fluid flowing therethrough is provided in the vicinity of the end of the discharge pipe 9d extending from the fluid outlet 9b, and from the cooling flow path 9 upstream of the pressure regulating valve 20. A second pressure sensor 19b for measuring the pressure of the fluid that has exited is provided.

  The mold 2 is cooled by a strong cooling mode (first cooling mode) in which water is supplied to the cooling flow path 9 through the water supply pipe 10 based on switching between the first electromagnetic valve V1 and the second electromagnetic valve V2, and an air supply pipe. 11 can be switched between a weak cooling mode (second cooling mode) in which air having a smaller heat capacity than water is flowed. The switching operation of the cooling mode and the control of the cooling state (flow rate of the cooling fluid) in each cooling mode are performed by the control unit 60 described later.

(Mold sensor)
In the vicinity of the narrow runner 2e that connects the cavity 2c of the fixed mold 2a and the overflow part 2d, there is a hot water sensor 22 that detects in real time the completion of hot water supply to the cavity 2c by the hot water supply device 3, and a mold. A mold sensor 30 in which a temperature sensor 23 for measuring the temperature in the vicinity of the second cavity 2c and a sensor cylinder 24 in the form of a steel cylinder are integrally incorporated is disposed.

  The molten metal sensor 22 has a sleeve-like insulator 25 inserted through the inner surface of the sensor body 24 and a wire-like detection terminal 26 inserted through the inner surface of the insulator 25. The detection terminal 26 is made of a special metal having a low coefficient of thermal expansion (for example, a Co—Ni—Cr alloy). The inner surface of the sensor main body 24 is open at both ends in the longitudinal direction, and both the insulator 25 and the detection terminal 26 are exposed at the tip of the sensor main body 24. At the tip, the sensor main body 24 and the insulator are exposed. 25 and the detection terminal 26 form substantially one plane with each other.

  A conducting wire 27 is connected to the base end of the detection terminal 26, and the other end of the conducting wire 27 is grounded. A power supply unit 28 such as a battery for generating a voltage at both ends of the conducting wire 27 and an energization detecting unit 29 capable of detecting a current flowing through the conducting wire 27 are connected in series to the conducting wire 27. The conducting wire 27 forms an electrical circuit that is electrically opened at the tip of the molten metal sensor 22 in a state before the molten metal is filled. In this electric circuit, when the sensor main body 24 and the tip of the detection terminal 26 are short-circuited by the molten metal reaching the vicinity of the runner 2e, the fixed mold 2a is separately grounded from the detection terminal 26 to the conductor 27 and from the conductor 27. Then, a closed circuit that reaches the sensor body 24 is obtained, and a current flows through the conductor 27. Therefore, it can be determined via the energization sensor 29 that the molten metal has reached the vicinity of the runner 2e.

  As the temperature sensor 23, an exposed type in which a thermal contact is exposed from the tip of a sheath 44 made of stainless steel is used as a thermocouple 45 of K type (alumel / chromel). As shown in FIG. 3, the sensor body 24 of the mold sensor 30 has an inner diameter that substantially matches the outer diameter (1 mm) of the sheath 44, and is formed with a pore 24 a that extends in parallel with the molten metal sensor 22. The thermocouple 45 is inserted into the pore 24a together with the sheath 44. The tip of the pore 24a does not penetrate and is closed by a portion of the sensor body 24 having a thickness of 3 to 5 mm.

  The rear end of the sheath 44 is closed by a washer-like closing member 46 through which a pair of strands of a thermocouple 45 is inserted, and the boundary between the closing member 46 and the sheath 44 is sealed with an alloy brazing 47 over the entire circumference. Has been. The space between the closing member 46 and the wire of the thermocouple 45 is also sealed with a thermoplastic resin or the like. These blockages prevent water and water vapor from entering the sheath 44 and damage the hot contacts and wires.

(control unit)
As shown in FIG. 4, the casting apparatus 100 includes a control unit 50 (an example of a control apparatus). The control unit 50 has a function of controlling various control elements of the casting apparatus 100. For this reason, the control unit 50 is configured as a computer system. The control unit 50 is connected with an inverter 16 for the water supply pipe 10, a compressor 18 for the air supply pipe 11, the first electromagnetic valve V1, the second electromagnetic valve V2, the pressure regulating valve 20, and the like as output devices. In addition, as an input device, an energization detection unit 29 of the hot water sensor 22, a temperature sensor 23, a first pressure sensor 19a, a second pressure sensor 19b, and the like are connected.

  In order to process signals input from various input devices and output required output signals to the various output devices, the control unit 50 is provided with a control unit 60 that is substantially composed of a program and a program execution device. ing. The function unit particularly related to the present invention in the control unit 60 includes a mode switching operation unit 41 (first switch) for switching the cooling device between the strong cooling mode (first cooling mode) and the weak cooling mode (second cooling mode). And a temperature control unit 42 (second control unit) that controls the cooling state (flow rate of the cooling fluid) in each cooling mode.

(Casting process)
As shown in FIG. 5A, the casting process includes “mold closing” in which the fixed mold 2a is pressed against the movable mold 2b, “hot water supply” in which the molten metal is poured into the hot water supply sleeve 4 from the hot water supply port 4a, and the plunger 6 "Injection filling" in which the molten metal is sent to the mold 2 and the pressure by the plunger 6 is maintained, and "solidification / molding" in which the molten metal in the cavity 2c is rapidly solidified by cooling the mold 2 in the strong cooling mode with water, After completion of solidification, the mold 2 is moved by moving the movable mold 2b, “mold opening”, the molded product is extruded from the movable mold 2b with the eject pin 8, “molded product extrusion”, and the molded product is unloaded from the casting apparatus 100. Proceed in the order of "Molded product unloading", "Release agent application" for applying a release agent to the inner surface of the mold 2, and "Air blow" for blowing away moisture that has entered the mold 2 during the release agent application. It is done. After “air blow”, it usually returns to “clamping” for the next shot (filling with molten metal).

After “injection filling” is completed, the mold 2 is rapidly cooled, so that the time required for “solidification / molding” can be shortened and the timing of “mold opening” can be advanced. If the start of rapid cooling is delayed, there is a possibility that defects such as burns may occur in the molded product. Further, if “mold opening” is performed in a state where sufficient coagulation cannot be obtained, there is a risk that the molded product may be distorted.
Next, when the solidification of the molten metal is completed, overcooling of the mold 2 can be prevented by immediately slowing down the cooling of the mold 2. If “injection filling” is performed in a state where the mold 2 is supercooled, there is a risk that defects such as sink marks may occur in the molded product.

  Therefore, in order to perform continuous casting by repeating the above-described casting process as efficiently as possible and so that there are no defects in the molded product, when injection filling of the molten metal into the mold 2 is completed, It is considered necessary to start cooling in the strong cooling mode without delay as much as possible and to switch to the weak cooling mode as soon as possible to prevent overcooling when solidification is completed.

(Temperature adjustment routine)
In order to perform the switching between the strong cooling mode and the weak cooling mode described above at the ideal timing as much as possible, the mode switching operation unit 41 (first control unit) of the control unit 60 is based on the temperature adjustment routine shown in FIG. Then, the mold 2 is cooled by the cooling device.
That is, during the control of the cooling device by the controller 60, it is determined whether the hot water sensor 22 is in an ON state or an OFF state (# 01), and when the hot water sensor 22 is in an ON state (yes determination). Cooling in the strong cooling mode with water is performed by setting only one solenoid valve V1 to the open position (# 02). On the other hand, when the hot water arrival sensor 22 is in the OFF state (no determination), only the second electromagnetic valve V2 is opened to perform cooling in the weak cooling mode using air (# 03).

When the flow of this temperature adjustment routine is viewed along the casting process of FIG. 5A, when the molten metal is filled into the cavity 2c by “injection filling”, the molten metal sensor 22 is turned on (FIG. 5B). Therefore, the mode switching operation unit 41 switches from the weak cooling mode to the strong cooling mode, and rapid cooling is started.
Next, when the “mold opening” is performed following the completion of “solidification / molding”, the molded product is separated from the molten metal sensor 22 (see FIG. 5C). 41, the strong cooling mode is switched to the weak cooling mode, and the slow cooling in the weak cooling mode is continued until the molten metal sensor 22 is turned on by the next “injection filling”.

In the strong cooling mode, the temperature control unit 42 (second control unit) controls the inverter 16 based on the temperature signal sent from the temperature sensor 23 that measures the temperature in the vicinity of the cavity 2 c of the mold 2, thereby pumping The number of rotations of 15 is adjusted, and feedback control is performed so that the temperature detected by the temperature sensor 23 approaches a preset target temperature. An appropriate target temperature value may be in the range of 250 to 300 ° C. as an example in the case of an aluminum alloy having a molten metal temperature in the ladle of around 700 ° C. However, since the appropriate target temperature value is greatly influenced by the volume of the cavity 2c, the mass of the mold 2, the capacity of the cooling device, and the like, the above range is only an example.
Similarly, in the weak cooling mode, the temperature control unit 42 adjusts the opening of the pressure regulating valve 20 based on the pressure signals sent from the first pressure sensor 19a and the second pressure sensor 19b, and detects the temperature sensor 23. Feedback control is performed so that the temperature becomes a preset target temperature (for example, within a range of 200 to 250 ° C.).

[Another embodiment]
<1> In addition to the above-described one that uses the conductivity of the molten metal as a “molten metal sensor” for accurately determining the timing of molten metal arrival in the cavity, for example, the center of gravity movement of the mold based on the molten metal filling is used. , A sensor that detects the difference between the output values of strain gauges arranged at multiple locations on the lower surface of the mold, or by measuring the temperature of the overflow portion from a diagonally spaced position, it can be applied to the overflow portion based on the filling of the molten metal. An infrared radiation temperature sensor for detecting the appearance of the molten metal surface can be applied.

<2> As in the above-described embodiment, switching between the strong cooling mode and the weak cooling mode having different cooling efficiencies is not performed by changing the type of cooling fluid, but using a single type of cooling fluid. However, it is also possible to switch between the strong cooling mode and the weak cooling mode. As an example, two flow paths are provided as the cooling flow path 9 passing through the inside of the mold 2, and the cooling fluid is allowed to flow through one of the flow paths (strong cooling mode). This can be realized by providing a flow path switching valve that switches between the states (weak cooling mode) and the first control unit controlling the flow path switching valve.

<3> The temperature control in each cooling mode is not limited to the method by only adjusting the flow rate of the cooling fluid, but by providing a mechanism for heating and cooling the cooling fluid outside the mold, You may implement | achieve by the structure which adjusts the temperature of the fluid itself by feedback control.

  A mold having a cavity for receiving molten metal and a cooling flow path through which a cooling fluid passes, a hot water supply apparatus for supplying molten metal to the cavity, a refrigerant supply apparatus for flowing cooling fluid through the cooling flow path, and measuring the temperature of the mold According to the progress of the process performed on the temperature sensor and the mold, the refrigerant supply device is switched between two cooling modes having different cooling efficiencies, and each cooling is performed based on the temperature measurement value detected by the temperature sensor. The present invention can be used as an invention for improving a casting apparatus having a control unit for controlling a cooling state in a mode.

2: Mold 2a: Fixed mold 2b: Movable mold 2c: Cavity 3: Hot water supply device 6: Plunger 9: Cooling flow path 10: Water supply pipe 11: Air supply pipe 15: Pump 16: Inverter 18: Compressor 19a: First pressure sensor 19b: Second pressure sensor 22: Hot water sensor 23: Temperature sensor 24: Sensor body 26: Detection terminal 29: Energization detection unit 30: Mold sensor 41: Mode switching operation unit (first control unit)
42: Temperature controller (second controller)
50: Control unit 60: Control unit 100: Casting device

Claims (4)

A mold having a cavity for receiving molten metal and a cooling flow path through which a cooling fluid passes,
A hot water supply device for supplying molten metal to the cavity;
A refrigerant supply device for flowing the cooling fluid through the cooling flow path;
A temperature sensor for measuring the temperature of the mold,
A hot water sensor for detecting completion of hot water supply to the cavity by the hot water supply device;
A first control unit that switches the refrigerant supply device between two cooling modes having different cooling efficiencies based on a hot water signal detected by the hot water sensor, and a temperature measurement value detected by the temperature sensor. A casting apparatus comprising: a second control unit that controls a cooling state in each cooling mode based on the second control unit. The hot water sensor has an electric circuit closed by the conductive molten metal supplied to the mold, and an energization detection unit for electrically detecting opening and closing of the electric circuit,
The first control unit switches the refrigerant supply device from the first cooling mode to the second cooling mode having a lower cooling efficiency based on a mold release signal generated by the casting product being separated from the molten metal sensor. The casting apparatus according to claim 1. The casting apparatus according to claim 1 or 2, wherein the hot water sensor and the temperature sensor are attached to a common sensor body. The temperature sensor includes a cylindrical sensor body attached to the mold such that a closed tip is exposed on the inner wall surface of the cavity, and an exposed sheath thermocouple inserted into the sensor body. The casting apparatus according to any one of claims 1 to 3, further comprising: a seal member that seals a rear end of the sensor body in a state where an exposed sheath thermocouple is confined in the sensor body.

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