JP7510282B2 - Water heaters and die casting machines - Google Patents

Description

This invention relates to a water supply device and a die casting machine, and in particular to a water supply device having a ladle that draws molten metal from a melting furnace and a die casting machine equipped with such a water supply device.

Conventionally, die casting machines equipped with a water supply device having a ladle that draws molten metal from a melting furnace are known (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 discloses a die casting machine equipped with a molten metal supply device having a ladle. This die casting machine is equipped with a ladle that draws up molten metal from a melting furnace, an injection sleeve into which the molten metal drawn up by the ladle is poured, an advance/retract drive means that moves the injection plunger back and forth within the injection sleeve, and a molten metal level detection sensor that measures the molten metal level of the molten metal poured from the ladle into the injection sleeve. After the molten metal is poured into the injection sleeve through the inlet of the injection sleeve by the ladle, this die casting machine measures the molten metal level in the inlet from above the inlet using a magnetostrictive molten metal level detection sensor, and calculates the total amount of molten metal in the injection sleeve from the measured molten metal level. The obtained total amount of molten metal is used to set a switching position that switches the injection operation during the injection process of the injection plunger.

JP 2018-171626 A

However, in the above-mentioned Patent Document 1, the level of the molten metal in the injection sleeve is measured after the molten metal is injected into the injection sleeve, which lengthens the time required from when the molten metal is injected into the injection sleeve until the injection plunger starts to inject the molten metal. As a result, there is a problem in that the temperature of the molten metal in the injection sleeve drops. The drop in temperature of the molten metal is a factor in reducing the quality of the molded product.

That is, when the molten metal is injected from the ladle into the injection sleeve, it spreads inside the injection sleeve, increasing its surface area (the area of contact with the inner surface of the injection sleeve and the area of the molten metal surface), and heat dissipation is promoted through the injection sleeve, causing a sudden drop in temperature inside the injection sleeve. The drop in temperature of the molten metal can cause undesirable phenomena in terms of the quality of the molded product, such as poor flow inside the mold (the molten metal does not reach every corner of the mold cavity) and an increase in the amount of broken chill layers (metal solidified inside the injection sleeve) mixed into the product.

In addition, waves occur on the surface of the molten metal immediately after injection, but because the injection sleeve is a long cylindrical member, it takes time for the waves to decay. Therefore, if measurements are taken without waiting for the waves to decay, errors in the measurement of the molten metal surface height due to the waves are likely to increase, and if measurements are taken while waiting for the waves to decay, the time required for measurement increases, resulting in a drop in the molten metal temperature.

This invention was made to solve the problems described above, and one objective of the invention is to provide a molten metal supply device and die casting machine that can measure the amount of molten metal supplied to the injection sleeve while suppressing a drop in the temperature of the molten metal in the injection sleeve.

In order to achieve the above-mentioned object, a water supply device in a first aspect of the present invention comprises a ladle for receiving molten metal, a ladle moving mechanism for drawing molten metal from a molten metal furnace into the ladle and moving the ladle so as to pour the drawn molten metal into the injection sleeve, a molten metal detection unit for detecting the molten metal drawn into the ladle before pouring it into the injection sleeve, and a control unit for acquiring the amount of molten metal in the ladle based on the detection result of the molten metal detection unit , wherein the molten metal detection unit includes an image sensor for acquiring an image of the surface of the molten metal in the ladle, and the control unit is configured to acquire the amount of molten metal in the ladle based on the surface height of the molten metal in the molten metal surface image or the surface area of the molten metal in the molten metal surface image .

In the molten metal supply device according to the first aspect of the present invention, as described above, a molten metal detection unit that detects the molten metal pumped up into the ladle before pouring into the injection sleeve and a control unit that acquires the amount of molten metal in the ladle based on the detection result of the molten metal detection unit are provided . The molten metal detection unit includes an image sensor that acquires an image of the surface of the molten metal in the ladle, and the control unit is configured to acquire the amount of molten metal in the ladle based on the height of the molten metal in the image of the molten metal or the area of the molten metal in the image of the molten metal. This makes it possible to acquire the amount of molten metal pumped up from the molten metal furnace into the ladle before pouring into the injection sleeve. Since the amount of molten metal can be acquired while the molten metal is held in the ladle, no waiting time occurs after pouring into the injection sleeve, and the injection process can be started promptly. Note that the surface area of the molten metal in the ladle is smaller than that in the injection sleeve, and the temperature of the ladle itself approaches the molten metal temperature due to contact between the ladle and the molten metal in the molten metal furnace during pumping, so the temperature of the molten metal decreases at a much slower rate than in the injection sleeve. In addition, since the surface area of the molten metal in the ladle is smaller than that in the injection sleeve, even if waves occur on the molten metal surface in the ladle, the waves quickly decay. Therefore, the molten metal can be detected quickly while suppressing a drop in temperature of the molten metal. As a result, the amount of molten metal supplied to the injection sleeve can be measured while suppressing a drop in temperature of the molten metal in the injection sleeve.

In the water supply device according to the first aspect described above, the control unit is preferably configured to obtain the amount of molten metal in the ladle after detection by the molten metal detection unit and before the pouring of molten metal into the injection sleeve is completed. With this configuration, the amount of molten metal to be supplied to the injection sleeve (i.e., the amount of molten metal in the ladle) can be reliably obtained by the time pouring is completed. As a result, the injection process of the injection device can be started using the obtained amount of molten metal immediately after pouring is completed, without creating a waiting time after pouring. This makes it possible to effectively suppress a decrease in the temperature of the molten metal, improving the quality and production efficiency of the molded product.

In the above-mentioned molten metal supply device according to the first aspect, the molten metal detection unit is preferably provided at a position above the molten metal furnace and detects the molten metal in the ladle that is raised from the molten metal furnace during pumping. With this configuration, the molten metal in the ladle when the molten metal is pumped from the molten metal furnace can be detected at the beginning of the molten metal supply operation. Therefore, the time from when the molten metal is detected to when it is poured into the injection sleeve can be maximized. Here, since the shorter the casting cycle time of the die casting machine, the higher the production efficiency, the shorter the time that the control unit can allocate to the calculation process for calculating the amount of molten metal may be. With the above configuration, a sufficient amount of time can be ensured between when the detection result is obtained and when the control unit calculates the amount of molten metal, thereby avoiding the occurrence of waiting time and enabling the production of molded products with high quality and high production efficiency.

In this case, the molten metal detection unit preferably includes a sensor that detects the molten metal, a housing that houses the sensor, and a refrigerant pipe that supplies refrigerant into the housing. This configuration effectively blocks the effect of heat from the molten metal furnace on the sensor of the molten metal detection unit. As a result, even if the molten metal detection unit is positioned above the molten metal furnace, it can detect the molten metal with high accuracy without being affected by heat.

In the water supply device according to the first aspect above, preferably, the ladle movement mechanism includes an arm that holds the ladle, and the molten metal detection unit is provided on the arm and detects the molten metal from above the ladle. With this configuration, the molten metal detection unit can be moved in conjunction with the movement of the ladle, so that molten metal can be detected at any position and timing on the movement trajectory of the ladle from the molten metal furnace to the injection sleeve. Therefore, the position and timing of molten metal detection can be easily optimized according to the molten metal supply operation.

In the above-mentioned water supply device according to the first aspect, the molten metal detection unit is preferably provided to detect the molten metal from above the ladle at a position belonging to the first half of the ladle's movement trajectory from the molten metal furnace to the injection sleeve. With this configuration, the molten metal can be detected at an early stage in the process of the ladle moving from the molten metal furnace to the injection sleeve. Therefore, sufficient time can be secured to perform the calculation process of the amount of molten metal after the detection of the molten metal until the completion of pouring. As a result, the occurrence of waiting time for the calculation process to be completed is suppressed, and molded products can be produced with high production efficiency while effectively suppressing the drop in the temperature of the molten metal.

A molten metal supplying device according to a second aspect of the present invention includes a ladle for receiving molten metal, a ladle movement mechanism for pumping molten metal from a molten metal furnace into the ladle and moving the ladle so as to pour the pumped molten metal into the injection sleeve, a molten metal detection unit for detecting the molten metal pumped into the ladle before pouring into the injection sleeve, and a control unit for acquiring the amount of molten metal in the ladle based on the detection result of the molten metal detection unit, the molten metal detection unit including a displacement sensor for measuring the width of the molten metal surface in the ladle , and the control unit is configured to acquire the amount of molten metal in the ladle based on the width of the molten metal surface measured by the molten metal detection unit . With this configuration, the molten metal in the ladle can be easily detected by the displacement sensor. Since the width of the molten metal surface changes depending on the amount of molten metal in the ladle, the amount of molten metal in the ladle can be easily calculated from the obtained width of the molten metal surface.

In this case, preferably, the apparatus further includes a memory unit for storing a relational expression between the width of the molten metal surface in the ladle and the amount of molten metal in the ladle, and the control unit is configured to obtain the amount of molten metal in the ladle from the detected width of the molten metal surface and the relational expression. With this configuration, the relational expression between the measurement value of the displacement sensor (the height of the molten metal surface or the width of the molten metal surface) and the amount of molten metal in the ladle is determined in advance by experiment or simulation, and during operation of the apparatus, the amount of molten metal can be obtained quickly and accurately by a calculation process with a small processing load that only involves applying the measurement value of the displacement sensor to the relational expression.

In this case, preferably, the apparatus further includes a storage unit for storing a relational expression between the range of molten metal in the molten metal surface image and the amount of molten metal in the ladle, or a relational expression between the surface area of molten metal in the molten metal surface image and the amount of molten metal in the ladle, and the control unit is configured to obtain the amount of molten metal in the ladle from the surface height of the molten metal range in the acquired molten metal surface image and the relational expression between the range of molten metal in the molten metal surface image and the amount of molten metal in the ladle, or to obtain the amount of molten metal in the ladle from the surface area of molten metal in the acquired molten metal surface image and the relational expression between the surface area of molten metal in the molten metal surface image and the amount of molten metal in the ladle. With this configuration, the relational expression between the range of molten metal in the molten metal image and the amount of molten metal in the ladle can be obtained easily and with high accuracy by previously determining the value of the range of molten metal in the molten metal image and the amount of molten metal in the ladle by experiment or simulation.

A die casting machine according to a third aspect of the present invention comprises a molten metal supplying device which supplies molten metal into the injection sleeve, an injection device which injects the molten metal supplied to the injection sleeve, and a control unit. The molten metal supplying device includes a ladle which receives the molten metal, a ladle moving mechanism which draws the molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve, and a molten metal detection unit which detects the molten metal in the ladle before it is poured into the injection sleeve . The molten metal detection unit includes an image sensor which obtains an image of the surface of the molten metal in the ladle. The control unit is configured to obtain the amount of molten metal in the ladle based on the detection result of the molten metal detection unit . The control unit is configured to obtain the amount of molten metal in the ladle based on the surface height of the molten metal in the molten metal surface image or the surface area of the molten metal in the molten metal surface image .

A die casting machine according to a third aspect of the present invention includes a molten metal supply device including a molten metal detection unit that detects the molten metal in the ladle before it is poured into the injection sleeve, and a control unit that acquires the amount of molten metal in the ladle based on the detection result of the molten metal detection unit, the molten metal detection unit including an image sensor that acquires an image of the surface of the molten metal in the ladle, and the control unit is configured to acquire the amount of molten metal in the ladle based on the height of the molten metal in the image of the surface of the molten metal or the surface area of the molten metal in the image of the surface of the molten metal. This makes it possible to measure the amount of molten metal supplied to the injection sleeve while suppressing a decrease in the temperature of the molten metal in the injection sleeve, as in the first aspect.
In addition, a die casting machine according to a fourth aspect of the present invention includes a molten metal supplying device that supplies molten metal into the injection sleeve, an injection device that injects the molten metal supplied to the injection sleeve, and a control unit, wherein the molten metal supplying device includes a ladle that receives the molten metal, a ladle moving mechanism that draws molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve, and a molten metal detection unit that detects the molten metal in the ladle before being poured into the injection sleeve, the molten metal detection unit including a displacement sensor that measures a molten metal surface width of the molten metal in the ladle, and the control unit is configured to obtain the amount of molten metal in the ladle based on the detection result of the molten metal detection unit, and the control unit is configured to obtain the amount of molten metal in the ladle based on the molten metal surface width measured by the molten metal detection unit.

As described above, the present invention makes it possible to measure the amount of molten metal being supplied to the injection sleeve while suppressing the temperature drop of the molten metal in the injection sleeve.

1 is a diagram showing a schematic diagram of an overall configuration of a die casting machine according to an embodiment; 1 is a diagram illustrating a schematic configuration of a water heating device according to one embodiment. FIG. 4 is a diagram showing a schematic diagram of the positional relationship between a ladle and a molten metal detector at a detection position. FIG. 13 is a diagram for explaining acquisition of a molten metal surface range based on a molten metal surface image. FIG. 2 is a diagram showing an example of the configuration of a molten metal detector provided above a molten metal furnace. FIG. 2 is a block diagram showing the relationship between a control unit and each part of the die casting machine. 1 is a graph showing a relationship between an image molten metal surface height, which is an example of a molten metal surface range, and an amount of molten metal. 1 is a graph for explaining a relational expression between a range of molten metal and an amount of molten metal. FIG. 2 is a diagram showing a schematic diagram of 3D data of molten metal in a ladle. FIG. 4 is a flow chart showing an example of a control operation of a control unit. FIG. 1 is a schematic diagram for explaining an injection step. FIG. 11 is a diagram showing a schematic diagram of the positional relationship between a molten metal detection unit and a ladle in a second embodiment. FIG. 13 is a diagram for explaining acquisition of the molten metal surface range based on the molten metal surface image in the example of FIG. 12 . 1 is a graph showing a relationship between a molten metal surface area, which is an example of a molten metal surface range, and an amount of molten metal. FIG. 13 is a diagram for explaining the installation position of the molten metal detection unit according to the third embodiment. FIG. 4 is a diagram for explaining a first example of the molten metal surface height detected by the molten metal detection unit. FIG. 11 is a diagram for explaining a second example of the molten metal level detected by the molten metal detection unit. FIG. 13 is a diagram for explaining a method for acquiring the molten metal surface width according to the fourth embodiment. FIG. 2 is a diagram for explaining the relationship between the molten metal surface width and the amount of molten metal. 13A and 13B are diagrams showing modified examples of the installation position of the molten metal detector.

The following describes an embodiment of the present invention with reference to the drawings.

[First embodiment]
The configuration of a die casting machine 1 equipped with a molten metal supply device 20 according to a first embodiment will be described with reference to FIGS. 1 to 11.

(Die casting machine configuration)
1, the die casting machine 1 includes an injection device 10, a molten metal supply device 20, a clamping device 30, and a control unit 40. The injection device 10 injects molten metal 5 from an injection sleeve 3 into a mold 2. The molten metal supply device 20 supplies molten metal 5 to the injection sleeve 3. The clamping device 30 holds the mold 2, and opens, closes, and clamps the mold 2. The molten metal 5 is a liquid metallic material.

The die casting machine 1 is a horizontal machine in which a movable die 2a is moved horizontally. The die casting machine 1 is also a cold chamber type machine, and is configured to manufacture a die casting product (molded product) by injecting molten metal 5 into a die 2 (cavity C) attached to a clamping device 30 using an injection device 10.

The mold 2 is configured to be separable, and is configured to form a cavity C (hollow portion) for molding a die-cast product (molded product). The mold 2 includes a moving mold 2a and a fixed mold 2b. The fixed mold 2b is fixed to a fixed die plate 32 of the mold clamping device 30. The moving mold 2a is attached to a moving die plate 31 of the mold clamping device 30. The mold clamping device 30 is configured to be movable in a direction (X direction) that moves the moving die plate 31 toward or away from the fixed die plate 32. The moving die plate 31 brings the moving mold 2a into contact with or away from the fixed mold 2b. The cavity C is formed by bringing the moving mold 2a into contact with the fixed mold 2b.

An injection sleeve 3 is connected to the mold 2 (fixed mold 2b). The injection sleeve 3 is connected to a cavity C inside the mold 2. The injection sleeve 3 is configured to accommodate a plunger 11 (described later) of the injection device 10 so that it can move in the X direction, and to accommodate the molten metal 5.

Specifically, the injection sleeve 3 includes a molten metal supply port 3a and a molten metal passage 3b. The injection sleeve 3 has a cylindrical shape. The injection sleeve 3 extends in the X direction. The molten metal supply port 3a opens at the top of the injection sleeve 3 and is provided so that the molten metal 5 can be supplied from above by the molten metal supply device 20 into the molten metal passage 3b. The molten metal passage 3b is a through hole that passes through the injection sleeve 3 in the X direction. The molten metal passage 3b is connected to the cavity C in the X1 direction.

The injection device 10 includes a plunger 11, a hydraulic cylinder 12, and a hydraulic circuit 13 for operating the hydraulic cylinder 12.

The plunger 11 is configured to inject the molten metal 5 supplied into the injection sleeve 3.

Specifically, the plunger 11 has a plunger tip 11a and a plunger rod 11b. The plunger tip 11a is removably attached to the end of the plunger rod 11b on the X1 direction side. The plunger rod 11b has a rod shape extending in the X direction. The plunger rod 11b is connected to the hydraulic cylinder 12 at the end on the X2 direction side.

The hydraulic cylinder 12 is configured to inject the molten metal 5 into the cavity C by moving the plunger 11 with hydraulic pressure supplied by the hydraulic circuit 13. The injection device 10 is configured to reciprocate the plunger 11 in the X direction within the injection sleeve 3 under the control of the hydraulic circuit 13.

The molten metal supply device 20 includes a ladle 21, a ladle movement mechanism 22, and a molten metal detection unit 23. The molten metal supply device 20 is configured to pump molten metal 5 from the molten metal furnace 4 using the ladle 21 and supply (supply) the pumped molten metal 5 to the injection sleeve 3.

The ladle 21 is a container that receives the molten metal 5. The ladle movement mechanism 22 is configured to pump the molten metal 5 from the molten metal furnace 4 into the ladle 21 and move the ladle 21 so as to pour the pumped molten metal 5 into the injection sleeve 3.

The molten metal detection unit 23 is configured to detect the molten metal 5 in the ladle 21 before it is poured into the injection sleeve 3.

The control unit 40 is configured to obtain the amount of molten metal in the ladle 21 based on the detection result of the molten metal detection unit 23. The control unit 40 is configured by a computer including a processor that performs calculation processing and a memory, and functions as a control unit by the processor executing a program. The control unit 40 may be provided in the water supply device 20 and configured to only control the water supply device 20, or may be configured to control the entire die casting machine 1 including the water supply device 20, the injection device 10, and the mold clamping device 30. In this embodiment, an example in which the control unit 40 controls the entire die casting machine 1 will be described.

(Configuration of hot water supply device)
A specific structure of water heating apparatus 20 will be described with reference to FIG.

<Ladle>
2, the ladle 21 includes a molten metal accommodation portion 21a capable of accommodating and holding the molten metal 5. The molten metal accommodation portion 21a has a bottom surface and peripheral side surfaces, is formed in a shape with an open top, and receives and holds the molten metal 5 therein. The ladle 21 has a connection portion 21b that protrudes laterally at the upper end portion, and is attached to the ladle movement mechanism 22 at the connection portion 21b.

Specifically, the ladle 21 is attached to the arm 51e (described later) via the shaft 54g provided at the connection part 21b in a state in which it can rotate (tilt) up and down around the shaft 54g. The ladle 21 is configured so that the amount of molten metal pumped from the molten metal furnace 4 can be adjusted by changing the rotation angle (tilt angle) around the shaft 54g.

<Ladle movement mechanism>
The ladle moving mechanism 22 is composed of a link mechanism in which a plurality of arms 51a to 51e are rotatably connected. The ladle moving mechanism 22 is equipped with drive motors 52a and 52b that drive the link mechanism. The ladle moving mechanism 22 moves the ladle 21 and rotates (tilts) the ladle 21 about the shaft 54g by the drive motors 52a and 52b.

The ladle movement mechanism 22 is configured to move the ladle 21 that draws up the molten metal 5 from the molten metal furnace 4 to the injection sleeve 3. The ladle movement mechanism 22 tilts the ladle 21 above the molten metal supply port 3a (see FIG. 1) of the injection sleeve 3, thereby pouring the molten metal 5 contained therein into the molten metal supply port 3a. The ladle movement mechanism 22 is also configured to move the ladle 21 to the molten metal furnace 4 after pouring.

The multiple arms 51a to 51e are configured to operate in conjunction with one another. As a result, the multiple arms 51a to 51e are configured to move the ladle 21 between the molten metal furnace 4 and the injection sleeve 3 along a predetermined movement trajectory ML.

The arm 51a is connected to the drive motor 52a via a drive transmission member 53a such as a chain or a belt. The arm 51a is configured to rotate in the C1 and C2 directions, which are rotational directions with the shaft 54a as the center of rotation, by the driving force from the drive motor 52a. The C1 direction is a rotational direction that moves the ladle 21 toward the injection sleeve 3. The C2 direction is a rotational direction opposite to the C1 direction and moves the ladle 21 toward the molten metal furnace 4. One end of the arm 51a in the longitudinal direction is connected to the shaft 54a. The shaft 54a is held by the water heater main body 20a so as to be rotatable in the C1 and C2 directions.

The other longitudinal end of arm 51a is connected to a position between both ends of arm 51b via shaft 54b. One longitudinal end of arm 51b is connected to one end of arm 51c via shaft 54c. The other longitudinal end of arm 51c is connected to one end of arm 51d via shaft 54d. Arm 51d is configured to rotate around shaft 54d. Shaft 54d is held by water heater main body 20a.

The other end of arm 51d in the longitudinal direction is connected to one end of arm 51e via shaft 54e. The other end of arm 51b in the longitudinal direction is connected to a position between both ends of arm 51e via shaft 54f. The other end of arm 51e in the longitudinal direction is connected to connection part 21b of ladle 21 via shaft 54g for rotating ladle 21.

A molten metal level detection sensor 55 is attached to the arm 51e via a holding member 55a. The molten metal level detection sensor 55 is provided to detect the molten metal level position of the molten metal 5 in the molten metal furnace 4. The molten metal level detection sensor 55 is, for example, an electrical sensor, and detects when the electrode rod comes into contact with the molten metal 5 (the molten metal level inside the furnace) in the molten metal furnace 4.

The drive motor 52a is a servo motor for driving the ladle moving mechanism 22. The drive motor 52b is a servo motor for driving the ladle 21. The servo motor includes an angle detector. The ladle 21 is connected to the drive motor 52b via a drive transmission member 53b such as a chain or belt. The driving force from the drive motor 52b causes the ladle 21 to rotate around the shaft 54g as the center of rotation. Both drive motors 52a and 52b are held in the water heater main body 20a.

<Molten metal detection section>
The molten metal detection unit 23 includes a sensor 61 for detecting the molten metal 5. The sensor 61 can include, for example, a displacement sensor that measures the distance to the molten metal 5 in the ladle 21, or an image sensor that captures an image of the inside of the ladle 21.

In the first embodiment, the sensor 61 is an image sensor that acquires an image 80 (see FIG. 4) of the surface of the molten metal 5 in the ladle 21. In other words, the molten metal detection unit 23 in the first embodiment is a camera that captures an image of the inside of the ladle 21. The image sensor is capable of capturing color images, for example, and is configured with a CMOS sensor or a CCD sensor.

In order to detect the molten metal 5 held in the ladle 21 with its top open, the molten metal detection unit 23 is disposed at a position above the movement trajectory ML of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3, and is set up to detect the molten metal 5 in the ladle 21 from above. Note that the upper position is a position higher than the ladle 21, and is not limited to directly above (vertically above).

In the first embodiment, the molten metal detection unit 23 is provided to detect the molten metal 5 from above the ladle 21 at a position that belongs to the first half of the movement trajectory ML of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3.

Specifically, the molten metal detection unit 23 is provided at a position above the molten metal furnace 4 and detects the molten metal 5 in the ladle 21 that is pulled up from the molten metal furnace 4 during pumping.

In the example of FIG. 2, the molten metal detection unit 23 is held at a position above the molten metal furnace 4 via a support member 70 installed on the upper surface of the wall portion 4a of the molten metal furnace 4. The support member 70 includes a pair of pillars 71 arranged on both sides of the opening 4b of the molten metal furnace 4, a beam portion 72 supported at both ends by the pair of pillars 71, and a bracket 73 fixed to the beam portion 72 and supporting the molten metal detection unit 23. Note that FIG. 2 illustrates one pillar portion 71 on the rear side of the paper (Y2 direction side), and another pillar portion (not shown) is arranged on the front side of the paper (Y1 direction side). The beam portion 72 extends in the Y direction so as to straddle the upper part of the molten metal furnace 4. The molten metal detection unit 23 is attached to the middle position of the beam portion 72 via the bracket 73. As a result, the molten metal detection unit 23 detects the molten metal 5 in the ladle 21 raised from the molten metal furnace 4 at a position above the molten metal furnace 4.

2 shows an example in which the molten metal detection unit 23 is provided to capture an image from an upper position of the molten metal furnace 4 diagonally downward. As shown in FIG. 3, the molten metal detection unit 23 captures an image of the molten metal 5 in the ladle 21, which is raised from the molten metal furnace 4 and placed in a substantially horizontal state at a preset height position. The molten metal detection unit 23 is provided to capture a molten metal surface image 80 (see FIG. 4) from a normal direction to the inner surface of the ladle where the edge of the molten metal surface 5a of the molten metal 5 is located. In other words, the installation angle of the molten metal detection unit 23 is adjusted so that the imaging optical axis 23a of the molten metal detection unit 23 is substantially perpendicular to the inner surface of the ladle at the edge of the molten metal surface 5a. The ladle 21 raised from the molten metal furnace 4 during pumping is tilted at a preset angle to return excess molten metal 5 to the molten metal furnace 4, and is adjusted to hold a substantially constant amount of molten metal corresponding to the tilt angle, and then returned to a horizontal position. Therefore, it can be assumed that the position of the molten metal surface 5a when detecting the molten metal will not vary significantly from the design value.

Here, the upper position of the molten metal furnace 4 is likely to become hot due to heat rising from within the molten metal furnace 4. Therefore, as shown in FIG. 5, in the first embodiment, the molten metal detection unit 23 includes a sensor 61 that detects the molten metal 5, a housing 62 that houses the sensor 61 inside, and a refrigerant pipe 63 that supplies a refrigerant 66 into the housing 62. The sensor 61, which is an image sensor, is disposed in a camera body 64 that includes a lens portion 64a. The housing 62 is a box-shaped member made of metal, and houses the camera body 64 inside. The housing 62 has a window member 62a for acquiring an image in front of the lens portion 64a. The sensor 61 generates a molten metal surface image 80 by detecting light incident on the lens portion 64a through the window member 62a. The window member 62a is a transparent member having heat resistance, such as heat-resistant glass. The window member 62a may have a filter for cutting infrared rays emitted from the molten metal 5. The filter is, for example, an ND filter.

The housing 62 is provided with connection holes 62b and 62c that penetrate the housing 62. A wiring 64b to the camera body 64 is inserted into the connection hole 62b. A cable hose 65 that houses the wiring 64b is attached to the connection hole 62b. A refrigerant pipe 63 is inserted into the connection hole 62c. One or more connection holes 62c are provided in the housing 62. In FIG. 5, two refrigerant pipes 63 are inserted into the two connection holes 62c, respectively.

The refrigerant pipe 63 supplies a refrigerant 66 from a refrigerant supply source outside the housing 62 to the inside of the housing 62. The refrigerant 66 is a gas or liquid. The refrigerant 66 is, for example, air, but a liquid refrigerant such as water may be supplied after waterproofing is performed, such as by covering the camera body 64 with a waterproof jacket.

In the first embodiment, the refrigerant 66 is air. Air at approximately the same temperature as the outside temperature of the housing 62 is supplied as the refrigerant 66 to the inside of the housing 62 by an air pump or the like. When air is used as the refrigerant 66, it is easy to handle because there is no need to consider refrigerant leakage (airtight sealing) from the housing 62, and since it has high thermal insulation properties, it also has the effect of blocking heat transfer from the housing 62 to the camera body 64. The refrigerant pipe 63 is provided in the housing 62 so as to supply the refrigerant 66 toward the lens portion 64a. Therefore, the refrigerant 66 in a particularly low temperature state is supplied to the lens portion 64a, which is easily affected by heat. After being discharged toward the lens portion 64a, the refrigerant 66 diffuses inside the housing 62 and cools the camera body 64 including the sensor 61. The refrigerant 66 is discharged through the cable hose 65 via the connection hole 62b.

The refrigerant 66 is continuously supplied while the die casting machine 1 is in operation. Therefore, a flow of low-temperature refrigerant 66 is constantly formed within the housing 62. Note that, although the two refrigerant pipes 63 in FIG. 5 are both supply pipes, a supply pipe for the refrigerant 66 and a discharge pipe for the refrigerant 66 may also be provided.

(Control Unit)
Next, a description will be given of a configuration for controlling each part of the die casting machine 1. As shown in Fig. 6, in the first embodiment, the die casting machine 1 includes a control unit 40, a storage unit 41, an image processing unit 42, an input unit 43, and a notification unit 44.

The control unit 40 controls the operation of the ladle moving mechanism 22 based on the detection signals of the angle detector 52c of the drive motor 52a and the angle detector 52d of the drive motor 52b. The image processing unit 42 processes the molten metal surface image 80 detected by the molten metal detection unit 23. The memory unit 41 stores a relational expression 90 between the molten metal range in the molten metal surface image 80 and the amount of molten metal in the ladle 21.

The control unit 40 controls the injection operation based on the detection signal of the rod position detector 15 provided in the injection device 10. The control unit 40 sets the switching position of the injection process based on the acquired amount of molten metal in the ladle 21. This makes it possible to optimize the injection operation control according to the amount of molten metal supplied from the ladle 21 in each injection process. The input unit 43 includes an input device such as a key switch that allows the user to input operations to the control unit 40. The notification unit 44 is composed of, for example, a speaker, a lamp, a monitor, etc., and notifies the user.

<How to obtain the amount of molten metal>
Next, a method for acquiring the amount of molten metal will be described. As shown in Fig. 4, when a molten metal surface image 80 is acquired by the molten metal detection unit 23, a binarization process is performed by the image processing unit 42. The image processing unit 42 distinguishes between the molten metal 5 and other parts based on the brightness value of the molten metal surface image 80, and binarizes the image. Fig. 4 shows a black and white binarized image, in which the molten metal 5 part in the ladle 21 is shown in white, and the other parts than the molten metal 5 are shown in black.

The control unit 40 acquires a molten metal range 81 in which the molten metal 5 appears from the molten metal surface image 80a after binarization processing. The molten metal range 81 is information that represents the range of the molten metal 5 that appears in the image. In the molten metal surface image 80a captured from an oblique direction, the molten metal range 81 is the image molten metal surface height Hg from the lowest point in the image to the upper end position of the molten metal surface 5a. The greater the amount of molten metal 5 in the ladle 21, the higher the upper end position of the molten metal surface 5a in the image moves, so the image molten metal surface height Hg is an indicator of the amount of molten metal in the ladle 21.

The control unit 40 is configured to obtain the amount of molten metal M in the ladle 21 based on the molten metal range 81 in the acquired molten metal surface image 80 and the relational equation 90 stored in the memory unit 41.

Relational formula 90 is obtained in advance by an experimental method or a simulation, and is stored in the memory unit 41. Specifically, an experiment is performed to actually measure the image molten metal surface height Hg and the amount of molten metal M in the ladle 21 at that time in association with each other. Measurement results are obtained for various amounts of molten metal M, and an approximation formula for calculating the amount of molten metal M corresponding to the image molten metal surface height Hg is obtained as relational formula 90 (see FIG. 6).

Figure 7 shows a graph 91 in which the image molten metal surface height Hg is plotted against the corresponding amount of molten metal M. In graph 91, the vertical axis represents the image molten metal surface height (number of pixels) and the horizontal axis represents the amount of molten metal (g). Each plotted point in graph 91 is an actual measurement. The amount of molten metal may be expressed by weight or volume.

From the plot of graph 91, for example, by linear approximation, a relational expression 90 can be obtained. Fig. 8 shows a graph 93 in which an approximation line representing the obtained relational expression 90 is added to the vicinity of the common range of the amount of molten metal in graph 91. Relational expression 90 is expressed by the following formula (1).
Amount of molten metal M = a × Hg + b ... (1)
The slope a and intercept b are constants obtained by approximation. Hg is the image water surface height obtained from the water surface image 80.

When determining relational expression 90 by simulation, for example as shown in Figure 9, 3D (three-dimensional) data 94 of the molten metal shape in the ladle 21 is created from design information, and the 3D data 94 is sliced for each height position to determine the amount of molten metal M (weight or volume) and the shape of the molten metal surface 5a. A simulation is performed using the determined amount of molten metal M (weight or volume) and molten metal surface shape, and data on the optical system (lens working distance, magnification, image sensor pixel pitch) in the molten metal detection unit 23 and the positional relationship with the ladle 21 (all known constants), and a theoretical formula for the amount of molten metal M corresponding to the image molten metal surface height Hg is derived, thereby obtaining relational expression 90.

The control unit 40 acquires the molten metal range 81 (image molten metal surface height Hg) from the molten metal surface image 80 of the molten metal detection unit 23 each time a molten metal supply operation is performed, and calculates the amount of molten metal M of the molten metal 5 pumped into the ladle 21 by substituting the acquired image molten metal surface height Hg into the relational expression 90. The control unit 40 is configured to acquire the amount of molten metal M in the ladle 21 after detection by the molten metal detection unit 23 and before the completion of pouring the molten metal into the injection sleeve 3.

(Die casting machine operation)
Next, the production operation of a molded product by the die casting machine 1 will be described with reference to FIG.

In step S1, the control unit 40 controls the water supply device 20 to pump the molten metal 5 from the molten metal furnace 4 with the ladle 21. The water supply device 20 operates to lower the ladle 21 from a position above the molten metal furnace 4, submerge the ladle 21 in the molten metal 5 contained in the molten metal furnace 4, and after the molten metal 5 is contained in the ladle 21, raise the ladle 21 to pull it out of the molten metal 5.

In step S2, the control unit 40 controls the water supply device 20 to tilt the ladle 21 at a predetermined angle during or after the pulling operation, and to perform a draining operation to return the excess molten metal 5 in the ladle 21 back into the molten metal furnace 4.

In step S3, the control unit 40 returns the ladle 21 to a horizontal state and controls the water supply device 20 so that the ladle 21 moves to a predetermined detection height position by the molten metal detection unit 23. The ladle 21 is positioned directly above the molten metal furnace 4, at the position shown in FIG. 3 relative to the molten metal detection unit 23.

In step S4, the control unit 40 controls the molten metal detection unit 23 to detect the molten metal 5. In the first embodiment, the molten metal detection unit 23 acquires a molten metal surface image 80.

In step S5a, the control unit 40 performs the above-mentioned process of acquiring the amount of molten metal, and in step S5b, controls the water supply device 20 to start the pouring operation. The water supply device 20 operates to pour the molten metal 5 into the water supply port 3a by moving the ladle 21 from a position above the molten metal furnace 4 to a position above the water supply port 3a of the injection sleeve 3 and tilting the ladle 21 to a predetermined pouring angle.

In step S6, the pouring operation is completed. Prior to this step S6, the process of acquiring the amount of molten metal in step S5a is completed. In step S7, the control unit 40 controls the injection device 10 to start the injection process. The injection process will be described later.

The control unit 40 also controls the water heater 20 to move the ladle 21 to a cleaning position (not shown) in step S8, and controls the water heater 20 to clean the inside of the ladle 21 by air blowing or the like in step S9. The control unit 40 causes the molten metal 5 remaining at the bottom of the ladle to be measured in step S10. The molten metal 5 remaining at the bottom of the ladle is measured by the molten metal detection unit 23. The control unit 40 determines whether the bottom of the ladle is clean in step S11, and if it is clean, returns the process to step S1 for the molten metal pouring operation of the next cycle. If the bottom of the ladle is not clean, the control unit 40 performs a notification process by the notification unit 44 in step S12, and returns the process to step S9.

<Injection process>
As shown in FIG. 11, in the injection process of step S7, the plunger 11, which is at the injection start position P0 in the injection sleeve 3, is advanced to the forward limit P3, so that the molten metal 5 in the injection sleeve 3 is injected into the cavity C of the mold 2. In the injection process, various processes such as a low-speed injection process, a high-speed injection process, and a pressure boosting process are performed according to the position of the plunger 11. The injection process may further include other processes. At the start of the injection process, the control unit 40 sets the switching positions of these various processes based on the amount of molten metal M (i.e., the amount of molten metal supplied into the injection sleeve 3) acquired in step S5a. That is, the high-speed injection process start position P1 and the pressure boosting process start position P2 are set based on the amount of molten metal M. As a result, the switching positions of the various processes are set to the optimum positions according to the amount of molten metal M.

After the switching position is set, the control unit 40 controls the injection device 10 to perform the low-speed injection process, the high-speed injection process, and the pressure increase process. This causes the molten metal 5 to fill the cavity C and solidify. The metal solidified in the cavity C becomes the molded product.

After the injection process of step S7, in step S13 of FIG. 10, the control unit 40 controls the mold clamping device 30 to open the mold. This allows the molded product to be removed. In step S14, the control unit 40 controls the mold clamping device 30 to close and clamp the mold. When each of the above steps is completed, the control unit 40 returns the process to step S1 and starts the next production cycle.

(Effects of the First Embodiment)
The effects of the first embodiment will be described.

In the first embodiment, as described above, a molten metal detection unit 23 is provided that detects the molten metal 5 pumped into the ladle 21 before pouring into the injection sleeve 3, and a control unit 40 is provided that acquires the amount of molten metal M in the ladle 21 based on the detection result of the molten metal detection unit 23. This makes it possible to acquire the amount of molten metal M pumped into the ladle 21 from the molten metal furnace 4 before pouring into the injection sleeve 3. Since the amount of molten metal M can be acquired while the molten metal 5 is held in the ladle 21, no waiting time occurs after pouring into the injection sleeve 3, and the injection process can be started promptly. Note that the surface area of the molten metal 5 in the ladle 21 is smaller than that in the injection sleeve 3, and the temperature of the ladle 21 itself approaches the molten metal temperature due to contact between the ladle 21 and the molten metal 5 in the molten metal furnace 4 during pumping, so the temperature of the molten metal 5 decreases at a much slower rate than in the injection sleeve 3. In addition, since the molten metal surface area in the ladle 21 is smaller than the molten metal surface area in the injection sleeve 3, even if waves occur on the molten metal surface 5a in the ladle 21, the waves quickly decay. Therefore, the molten metal can be detected quickly while suppressing a drop in the molten metal temperature. As a result, the amount of molten metal supplied to the injection sleeve 3 can be measured while suppressing a drop in the temperature of the molten metal 5 in the injection sleeve 3.

In the first embodiment, as described above, the control unit 40 is configured to obtain the amount of molten metal M in the ladle 21 after detection by the molten metal detection unit 23 and before the pouring of the molten metal into the injection sleeve 3 is completed. This makes it possible to reliably obtain the amount of molten metal 5 supplied to the injection sleeve 3 (i.e., the amount of molten metal M in the ladle 21) by the time the pouring is completed. As a result, the injection process of the injection device 10 can be started using the obtained amount of molten metal M immediately after the pouring is completed, without generating a waiting time after the pouring. This makes it possible to effectively suppress a decrease in the temperature of the molten metal, and improve the quality and production efficiency of the molded product.

In the first embodiment, as described above, the molten metal detection unit 23 is provided at a position above the molten metal furnace 4 and detects the molten metal 5 in the ladle 21 that is raised from the molten metal furnace 4 during pumping. This allows the molten metal 5 in the ladle 21 to be detected when the molten metal 5 is pumped from the molten metal furnace 4 at the beginning of the molten metal supply operation. Therefore, the time from when the molten metal 5 is detected until when it is poured into the injection sleeve 3 can be maximized. Here, since the shorter the casting cycle time of the die casting machine 1, the higher the production efficiency, the shorter the time that the control unit 40 can allocate to the calculation process for calculating the molten metal amount M. According to the above configuration, a sufficient time margin can be ensured between obtaining the detection result and when the control unit 40 calculates the molten metal amount M, thereby avoiding the occurrence of waiting time and enabling the production of molded products with high quality and high production efficiency.

In addition, in the first embodiment, as described above, the molten metal detection unit 23 includes a sensor 61 that detects the molten metal 5, a housing 62 that houses the sensor 61, and a refrigerant pipe 63 that supplies a refrigerant 66 into the housing 62. This effectively blocks the effect of heat from the molten metal furnace 4 on the sensor 61 of the molten metal detection unit 23. As a result, even when the molten metal detection unit 23 is disposed above the molten metal furnace 4, it is possible to perform highly accurate molten metal detection without being affected by heat.

In addition, in the first embodiment, as described above, the molten metal detection unit 23 is provided to detect the molten metal 5 from above the ladle 21 at a position belonging to the first half of the movement trajectory ML of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3. This allows the molten metal 5 to be detected at an early stage in the movement process of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3. Therefore, sufficient time can be secured to perform the calculation process of the molten metal amount M between the detection of the molten metal and the completion of pouring. As a result, the occurrence of waiting time for the calculation process to be completed is suppressed, and molded products can be produced with high production efficiency while effectively suppressing the drop in temperature of the molten metal 5.

In addition, in the first embodiment, as described above, the molten metal detection unit 23 includes an image sensor (sensor 61) that acquires a surface image 80 of the molten metal 5 in the ladle 21. This allows the image sensor to easily detect the molten metal 5 (molten metal surface 5a) in the ladle 21. Since the molten metal range 81 in the molten metal surface image 80 changes depending on the amount of molten metal M in the ladle 21, the amount of molten metal M in the ladle 21 can be calculated with high accuracy by performing image analysis on the obtained molten metal surface image 80.

In the first embodiment, as described above, the controller 40 is further provided with a memory unit 41 that stores a relational expression 90 between the molten metal range 81 in the molten metal surface image 80 and the amount of molten metal M in the ladle 21, and the controller 40 is configured to obtain the amount of molten metal M in the ladle 21 from the molten metal range 81 in the acquired molten metal surface image 80 and the relational expression 90. In this way, by determining the relational expression 90 between the molten metal range 81 in the molten metal surface image 80 and the amount of molten metal M in the ladle 21 in advance by experiment or simulation, when the device is in operation, the amount of molten metal M can be obtained easily and with high accuracy by simply applying the value of the molten metal range 81 obtained from the molten metal surface image 80 (image molten metal surface height Hg) to the relational expression 90.

[Second embodiment]
Next, a second embodiment will be described with reference to Figures 12 to 14. In the second embodiment, unlike the first embodiment configured to acquire the molten metal surface image 80 from diagonally above the ladle 21, an example will be described in which the molten metal surface image 80 is acquired from directly above the ladle 21. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted.

In the second embodiment, as shown in FIG. 12, the molten metal detection unit 23 is provided directly above the molten metal furnace 4 (see FIG. 2) with the imaging optical axis 23a facing downward. The molten metal detection unit 23 is provided so as to be suspended downward from a support member 70a disposed above the molten metal furnace 4, for example. The molten metal detection unit 23 is provided so as to acquire a molten metal surface image 80 from a normal direction to the molten metal surface 5a of the molten metal 5 in the ladle 21, which is raised from the molten metal furnace 4 and disposed in a substantially horizontal state. In other words, the installation angle of the molten metal detection unit 23 is adjusted so that the imaging optical axis 23a of the molten metal detection unit 23 is substantially perpendicular to the molten metal surface 5a.

The molten metal surface image 80 acquired in the second embodiment is a planar image of the molten metal surface 5a of the molten metal 5 in the ladle 21, as shown in FIG. 13. The control unit 40 acquires a molten metal range 81 in which the molten metal 5 is captured from the molten metal surface image 80a after binarization processing. In this case, the molten metal range 81 is the molten metal surface area A in the image (the number of pixels in the molten metal surface 5a portion (white portion) in the image). The greater the amount of molten metal 5 in the ladle 21, the larger the area of the molten metal surface 5a in the image, so the molten metal surface area A is an index of the amount of molten metal in the ladle 21.

Figure 14 shows a graph 92 in which the molten metal surface area A and the corresponding amount of molten metal M are plotted. In graph 92, the vertical axis represents the molten metal surface area (number of pixels) and the horizontal axis represents the amount of molten metal (g). Each plotted point in graph 92 is an actual measured value.

From the plots of graph 92, for example, linear approximation can be used to obtain relational expression 90. As shown in graph 93 in Fig. 8, an approximation line expressing relational expression 90 can be determined from the plots in the vicinity of the commonly used range of the amount of molten metal in graph 92. Relational expression 90 is expressed by the following formula (2).
Amount of molten metal M = a × A + b ... (2)
The slope a and the intercept b are constants obtained by approximation. A is the molten metal surface area obtained from the molten metal surface image 80. The relational expression 90 can also be obtained by a simulation using the 3D data 94 shown in FIG.

The control unit 40 acquires the molten metal range 81 (molten metal surface area A) from the molten metal surface image 80 of the molten metal detection unit 23 each time a molten metal supply operation is performed, and calculates the amount M of molten metal 5 pumped into the ladle 21 by substituting the acquired value into the relational expression 90.

The other configurations of the second embodiment are the same as those of the first embodiment. The effects of the second embodiment are the same as those of the first embodiment.

[Third embodiment]
Next, a third embodiment will be described with reference to Figures 15 to 17. In the third embodiment, an example will be described in which the molten metal detection unit includes a displacement sensor, unlike the first and second embodiments in which the molten metal detection unit includes an image sensor (camera). In the third embodiment, the same components as those in the first embodiment will be designated by the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted.

As shown in FIG. 15, in the third embodiment, the sensor 111 provided in the molten metal detection unit 23 is a displacement sensor that measures the height of the surface of the molten metal 5 in the ladle 21. The displacement sensor may be a sensor of any detection method, such as an optical sensor, an ultrasonic sensor, or a magnetostrictive sensor. The sensor 111 detects the molten metal 5 in the ladle 21 in a non-contact manner from a position away from the molten metal surface 5a.

In the third embodiment, the molten metal detection unit 23 is provided on the arm 51e and is configured to detect the molten metal 5 from above the ladle 21. The molten metal detection unit 23 is attached to the arm 51e via a bracket 112. Therefore, the molten metal detection unit 23 in the third embodiment is moved integrally with the ladle 21 supported at the end of the arm 51e by the ladle movement mechanism 22. Since the molten metal detection unit 23 is attached to the arm 51e that holds the ladle 21, the distance between the molten metal detection unit 23 and the ladle 21 is maintained constant. The detection direction of the molten metal detection unit 23 is set in a direction toward the ladle 21 along the longitudinal direction of the arm 51e.

When the molten metal detection unit 23 detects the molten metal 5, the ladle movement mechanism 22 is controlled so that the arm 51e is oriented in the vertical direction and the ladle 21 is in a horizontal state. As a result, the molten metal detection unit 23 detects the molten metal 5 from a direction perpendicular to the molten metal surface 5a, as in the example of FIG. 12. In the third embodiment, since the molten metal detection unit 23 moves together with the ladle 21, the detection timing (detection position) of the molten metal 5 is not particularly limited. For example, as shown in FIG. 2, the molten metal detection unit 23 may detect the molten metal 5 in the ladle 21 that is pulled up from the molten metal furnace 4 when the molten metal 5 is pumped up, or may detect the molten metal 5 in the middle of the movement trajectory ML of the ladle 21. The molten metal detection unit 23 may detect the molten metal 5 while the ladle 21 is moving along the movement trajectory ML.

Obtaining the amount of molten metal
In the third embodiment, the memory unit 41 (see FIG. 6 ) stores in advance a relational expression 90 between the molten metal level in the ladle 21 and the amount of molten metal M in the ladle 21. The control unit 40 is configured to acquire the amount of molten metal M in the ladle 21 from the detected molten metal level and the relational expression 90. In a configuration in which the molten metal detection unit 23 does not acquire a molten metal level image 80, the image processing unit 42 shown in FIG. 6 does not need to be provided, and it is sufficient for the control unit 40 to acquire the detection result of the molten metal detection unit 23.

For example, the sensor 111 is a one-dimensional displacement sensor. As shown in FIG. 16, the sensor 111 measures the distance Ls from the sensor 111 to the surface 5a of the molten metal 5 in the ladle 21. Before detecting the molten metal, the distance H0 (a constant value) to the inner bottom surface of the empty ladle 21 is stored in the memory unit 41. As a result, the surface height H of the molten metal 5 in the ladle 21 is obtained as H=H0-Ls. The surface height H is the distance from the inner bottom surface of the ladle 21 to the surface 5a. As shown in the graph 121 of FIG. 16, the amount of molten metal M increases with an increase in the surface height H. As in the first embodiment, the amount of molten metal M corresponding to the measured value of the surface height H is obtained experimentally or by simulation, and an approximation equation between the surface height H and the amount of molten metal M is stored in the memory unit 41 as a relational equation 90.

As shown in FIG. 17, the molten metal level may be the distance (L) from the upper end surface of the ladle 21 to the molten metal level 5a. The memory unit 41 stores in advance the distance L0 (a constant value) from the sensor 111 to the upper end surface of the ladle 21. As a result, the molten metal level L of the molten metal 5 in the ladle 21 is obtained as L = Ls - L0. As shown in graph 122 in FIG. 17, the amount of molten metal M decreases as the molten metal level L increases. The amount of molten metal M corresponding to the measured value of the molten metal level L is obtained experimentally or by simulation, and an approximation equation between the molten metal level L and the amount of molten metal M is stored in the memory unit 41 as relational equation 90.

With the above configuration, the control unit 40 obtains the molten metal surface height H or L from the molten metal detection unit 23 each time a molten metal supply operation is performed, and calculates the amount M of molten metal 5 pumped into the ladle 21 by substituting the obtained value into the relational equation 90.

The rest of the configuration of the third embodiment is the same as that of the first embodiment.

(Effects of the Third Embodiment)
The effects of the third embodiment will be described.

In the third embodiment, as in the first embodiment, a molten metal detection unit 23 is provided that detects the molten metal 5 pumped into the ladle 21 before pouring into the injection sleeve 3, and a control unit 40 is provided that acquires the amount of molten metal M in the ladle 21 based on the detection result of the molten metal detection unit 23. This makes it possible to measure the amount of molten metal supplied to the injection sleeve 3 while suppressing a decrease in the temperature of the molten metal 5 in the injection sleeve 3.

In addition, in the third embodiment, as described above, the ladle movement mechanism 22 includes an arm 51e that holds the ladle 21, and the molten metal detection unit 23 is provided on the arm 51e and detects the molten metal 5 from above the ladle 21. This allows the molten metal detection unit 23 to move in conjunction with the movement of the ladle 21, so that molten metal detection can be performed at any position and timing on the movement trajectory ML (see Figure 1) of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3. Therefore, the position and timing of molten metal detection can be easily optimized according to the supply operation of the molten metal 5.

In addition, in the third embodiment, as described above, the molten metal detection unit 23 includes a displacement sensor (sensor 111) that measures the surface height (H or L) of the molten metal 5 in the ladle 21. This allows the molten metal 5 in the ladle 21 to be easily detected by the displacement sensor. Since the surface height (H or L) changes depending on the amount of molten metal M in the ladle 21, the amount of molten metal M in the ladle 21 can be easily calculated from the obtained surface height (H or L).

In the third embodiment, as described above, the water heater 20 includes a memory unit 41 that stores a relational expression 90 between the molten metal level (H or L) in the ladle 21 and the amount of molten metal M in the ladle 21, and the control unit 40 is configured to obtain the amount of molten metal M in the ladle 21 from the detected molten metal level (H or L) and the relational expression 90. As a result, by determining the relational expression 90 between the measurement value of the displacement sensor (molten metal level H, L) and the amount of molten metal M in the ladle 21 in advance by experiment or simulation, the amount of molten metal M can be obtained quickly and accurately by a calculation process with a small processing load that simply applies the measurement value of the displacement sensor to the relational expression 90 during operation of the device.

The other effects of the third embodiment are the same as those of the first embodiment.

[Fourth embodiment]
Next, a fourth embodiment will be described with reference to Figures 15, 18, and 19. In the fourth embodiment, an example will be described in which the molten metal detection unit includes a two-dimensional displacement sensor, unlike the third embodiment in which the molten metal detection unit includes a one-dimensional displacement sensor. In the fourth embodiment, the same components as those in the third embodiment will be designated by the same reference numerals as those in the third embodiment, and descriptions thereof will be omitted.

As shown in FIG. 15, in the fourth embodiment, the sensor 111 provided in the molten metal detection unit 23 is a displacement sensor that measures the width of the surface of the molten metal 5 in the ladle 21. In the fourth embodiment, the sensor 111 is a two-dimensional displacement sensor. The two-dimensional displacement sensor can be, for example, a laser scanning type displacement sensor or an image sensor. For example, the measurement result along the measurement line 123 in FIG. 18 by a laser scanning type displacement sensor is graph 124. The vertical axis of graph 124 is the distance Ls from the sensor 111 (see FIGS. 16 and 17), and the horizontal axis is the position along the measurement line 123. Compared with the measurement result of the inner surface of the ladle in an empty state (not shown), the distance Ls becomes approximately constant in the area of the molten metal surface 5a, so that the boundary positions B1 and B2 between the inner surface of the ladle and the molten metal surface 5a can be detected. The distance between the boundary position B1 and the boundary position B2 is the molten metal surface width W. The control unit 40 acquires the width W of the molten metal surface 5a of the molten metal 5 in the ladle 21 based on the measurement results of the sensor 111. Note that the width of the molten metal surface 5a is not limited to that shown in the figure, and the width in any direction may be measured.

As shown in graph 125 of FIG. 19, the amount of molten metal M increases as the width W of the molten metal surface increases. As in the third embodiment, the amount of molten metal M corresponding to the measured value of the width W of the molten metal surface is obtained experimentally or by simulation, and an approximation equation between the width W of the molten metal surface and the amount of molten metal M is stored in the memory unit 41 as relational equation 90.

In this way, in the fourth embodiment, the memory unit 41 (see FIG. 6) prestores a relational expression 90 between the width W of the molten metal surface in the ladle 21 and the amount M of molten metal in the ladle 21. The control unit 40 is configured to obtain the amount M of molten metal in the ladle 21 from the detected width W of the molten metal surface and the relational expression 90.

The rest of the configuration of the fourth embodiment is the same as that of the third embodiment.

(Effects of the Fourth Embodiment)
The effects of the fourth embodiment will be described.

In the fourth embodiment, as in the third embodiment described above, it is possible to measure the amount of molten metal supplied to the injection sleeve 3 while suppressing a decrease in the temperature of the molten metal 5 in the injection sleeve 3.

In addition, in the fourth embodiment, as described above, the molten metal detection unit 23 includes a displacement sensor (sensor 111) that measures the surface width W of the molten metal 5 in the ladle 21. This allows the molten metal 5 in the ladle 21 to be easily detected by the displacement sensor. Since the surface width W changes depending on the amount of molten metal M in the ladle 21, the amount of molten metal M in the ladle 21 can be easily calculated from the obtained surface width W.

In the fourth embodiment, as described above, the water heater 20 includes a memory unit 41 that stores a relational expression 90 between the width W of the molten metal surface in the ladle 21 and the amount M of molten metal in the ladle 21, and the control unit 40 is configured to obtain the amount M of molten metal in the ladle 21 from the detected width W of the molten metal surface and the relational expression 90. As a result, by determining the relational expression 90 between the measurement value of the displacement sensor (width W of the molten metal surface) and the amount M of molten metal in the ladle 21 in advance by experiment or simulation, when the device is in operation, the amount M of molten metal can be obtained quickly and accurately by a calculation process with a small processing load that simply applies the measurement value of the displacement sensor to the relational expression 90.

The other effects of the fourth embodiment are the same as those of the third embodiment.

[Modification]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above first to fourth embodiments, the die casting machine 1 is configured as a horizontal type, but the present invention is not limited to this. In the present invention, the die casting machine may be configured as a vertical type.

In the above first to fourth embodiments, the control unit 40, which controls the entire die casting machine 1, calculates the amount of molten metal M, but the present invention is not limited to this. In the present invention, a control unit that controls the entire die casting machine 1 and a control unit that controls the water supply device 20 may be provided separately, and the amount of molten metal may be obtained by either control unit.

In the above first and second embodiments, the molten metal detection unit 23 is disposed above the molten metal furnace 4, and in the above third and fourth embodiments, the molten metal detection unit 23 is provided on the arm 51e, but the present invention is not limited to this. In the present invention, the molten metal detection unit 23 is not limited to the above-mentioned position as long as it is disposed above the movement trajectory ML of the ladle 21 from the molten metal furnace 4 to the injection sleeve 3. For example, in the example shown in FIG. 20, the molten metal detection unit 23 is disposed above the molten metal supply port 3a of the injection sleeve 3. In this case, for example, the molten metal detection unit 23 is attached to the frame of the mold clamping device 30 via a bracket or the like, and is disposed so that the detection direction is downward. The molten metal detection unit 23 detects the molten metal 5 in the ladle 21 immediately before pouring the molten metal into the molten metal supply port 3a.

In the third embodiment, the sensor 111 is a one-dimensional displacement sensor, and in the fourth embodiment, the sensor 111 is a two-dimensional displacement sensor, but the present invention is not limited to this. The sensor 111 may be a three-dimensional displacement sensor. The three-dimensional displacement sensor may be, for example, a 3D laser scanning type displacement meter or a stereo camera equipped with multiple image sensors. In this case, the sensor 111 acquires the three-dimensional shape inside the ladle 21. Before detecting the molten metal, the sensor 111 acquires three-dimensional shape data inside the ladle 21 in an empty state and stores it in the memory unit 41. When the molten metal 5 is pumped into the ladle 21, three-dimensional shape data up to the molten metal surface 5a inside the ladle 21 is acquired. The control unit 40 acquires the amount of molten metal V based on the difference between the three-dimensional shape data Vs after pumping the molten metal and the three-dimensional shape data V0 of the ladle 21 in an empty state (V = V0 - Vs). The amount of molten metal V in this case is acquired as the volume of the molten metal 5. In this modified example, the amount of molten metal V can be obtained by subtracting the three-dimensional shape data, so there is no need to obtain relational expression 90.

In the first embodiment, the injection process by the injection device 10 is controlled based on the amount of molten metal in the ladle 21, but the present invention is not limited to this. For example, the control unit 40 may determine the difference between the amount of molten metal acquired and the theoretical value of the amount of molten metal determined by the inclination angle of the ladle 21 each time the amount of molten metal is acquired, and judge the operating state of the water heater 20. For example, when a tendency for deviation from the theoretical value to increase or a tendency for the amount of molten metal to vary greatly is recognized, the notification unit 44 may notify the user to perform maintenance such as replacing consumables of the water heater 20. This allows the user to detect the occurrence of defective products or signs of malfunction of the water heater 20 in advance. In addition, for example, the control unit 40 may execute feedback control to bring the amount of molten metal pumped closer to the theoretical value by correcting the setting value of the inclination angle of the ladle 21 at the time of the next pumping of molten metal using the difference between the measured amount of molten metal and the theoretical value.

In the first and second embodiments, the molten metal detection unit 23 including an image sensor (camera) captures the molten metal surface image 80 in the ladle 21, but the present invention is not limited to this. For example, when the molten metal detection unit 23 is located above the molten metal furnace 4 as shown in FIG. 2, an image of the inside of the molten metal furnace 4 can be captured in a situation where the ladle 21 is not located at a predetermined detection position. Therefore, for example, the control unit 40 may obtain the molten metal surface height in the molten metal furnace 4 based on the captured image. In addition, the control unit 40 may obtain captured images during the operation of the water heater 20 periodically or as moving images, and monitor the status of the ladle 21 and the molten metal furnace 4 during the water heater operation based on the obtained captured images. The control unit 40 may perform image analysis on the obtained captured images to determine whether or not an abnormality has occurred in the ladle 21 or the molten metal furnace 4, and may notify the user if an abnormality has occurred.

In addition, in the case of the configuration shown in FIG. 20 in which the molten metal detection unit 23 is disposed at an upper position near the molten metal inlet 3a of the injection sleeve 3, an image of the surrounding area including the molten metal inlet 3a can be acquired. The control unit 40 may determine whether or not the molten metal 5 spills outside the molten metal inlet 3a during pouring based on the captured image. For example, when the control unit 40 detects molten metal spilling, it can determine that the tilt speed of the ladle 21 during pouring is excessive, and control the tilt speed of the ladle 21 to be reduced. This allows the pouring operation to be controlled so that the molten metal can be poured in the shortest possible time without causing molten metal spilling. For example, the control unit 40 may control the injection device 10 so that the plunger tip 11a is reflected inside the molten metal inlet 3a, and determine the wear state of the plunger tip 11a and the inner wall surface of the injection sleeve 3 based on the captured image.

REFERENCE SIGNS LIST 1 Die casting machine 3 Injection sleeve 4 Melting furnace 5 Molten metal 5a Melt surface 10 Injection device 20 Melting device 21 Ladle 22 Ladle movement mechanism 23 Molten metal detection unit 40 Control unit 41 Memory unit 51e Arm 61 Sensor (image sensor)
62 Housing 63 Refrigerant pipe 66 Refrigerant 80, 80a Molten metal surface image 81 Molten metal range 111 Sensor (displacement sensor)
H, L: Height of molten metal surface M, V: Amount of molten metal ML: Movement path W: Width of molten metal surface

Claims (11)

A ladle for receiving molten metal;
a ladle moving mechanism that draws molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve;
a molten metal detection unit that detects the molten metal pumped into the ladle before being poured into the injection sleeve;
A control unit that acquires an amount of molten metal in the ladle based on a detection result of the molten metal detection unit ,
The molten metal detection unit includes an image sensor for acquiring an image of the surface of the molten metal in the ladle,
The control unit is configured to obtain the amount of molten metal in the ladle based on the height of the molten metal surface in the molten metal surface image or the area of the molten metal surface in the molten metal surface image . The water heater according to claim 1, wherein the control unit is configured to obtain the amount of molten metal in the ladle after detection by the molten metal detection unit and before the injection of molten metal into the injection sleeve is completed. The water heater according to claim 1 or 2, wherein the molten metal detector is provided above the molten metal furnace and detects the molten metal in the ladle that is raised from the molten metal furnace during pumping. The hot water supply device according to claim 3, wherein the molten metal detection unit includes a sensor that detects the molten metal, a housing that houses the sensor, and a refrigerant pipe that supplies refrigerant into the housing. The ladle moving mechanism includes an arm that holds the ladle,
The water heating apparatus according to claim 1 or 2, wherein the molten metal detection unit is provided on the arm and detects the molten metal from above the ladle. The water heater according to any one of claims 1 to 5, wherein the molten metal detection unit is arranged to detect the molten metal from above the ladle at a position that belongs to the first half of the movement trajectory of the ladle from the molten metal furnace to the injection sleeve. A ladle for receiving molten metal;
a ladle moving mechanism that draws molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve;
a molten metal detection unit that detects the molten metal pumped into the ladle before being poured into the injection sleeve;
A control unit that acquires an amount of molten metal in the ladle based on a detection result of the molten metal detection unit,
The molten metal detection unit includes a displacement sensor that measures a molten metal surface width in a ladle ,
The control unit is configured to obtain the amount of molten metal in the ladle based on the molten metal surface width measured by the molten metal detection unit . A storage unit that stores a relational expression between a molten metal surface width in the ladle and an amount of molten metal in the ladle,
The molten metal supply apparatus according to claim 7 , wherein the control unit is configured to obtain the amount of molten metal in the ladle based on the detected molten metal surface width and the relational expression. A storage unit is further provided for storing a relational expression between a molten metal range in a molten metal surface image and an amount of molten metal in the ladle , or a relational expression between a molten metal surface area in a molten metal surface image and an amount of molten metal in the ladle ,
2. The water heating apparatus of claim 1, wherein the control unit is configured to obtain the amount of molten metal in the ladle based on a molten metal surface height of the molten metal range in the acquired molten metal surface image and a relationship between the molten metal range in the molten metal surface image and the amount of molten metal in the ladle, or to obtain the amount of molten metal in the ladle based on a molten metal surface area in the acquired molten metal surface image and a relationship between the molten metal surface area in the molten metal surface image and the amount of molten metal in the ladle . a melt supply device that supplies molten metal into the injection sleeve;
an injection device that injects the molten metal supplied to the injection sleeve;
A control unit,
The hot water supply device includes:
A ladle for receiving molten metal;
a ladle moving mechanism that draws molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve;
a molten metal detection unit that detects the molten metal in the ladle before pouring into the injection sleeve,
The molten metal detection unit includes an image sensor for acquiring an image of the surface of the molten metal in the ladle,
The control unit is configured to acquire an amount of molten metal in the ladle based on a detection result of the molten metal detection unit ,
The control unit is configured to obtain the amount of molten metal in the ladle based on a molten metal surface height in a molten metal surface image or a molten metal surface area in the molten metal surface image . a melt supply device that supplies molten metal into the injection sleeve;
an injection device that injects the molten metal supplied to the injection sleeve;
A control unit,
The hot water supply device includes:
A ladle for receiving molten metal;
a ladle moving mechanism that draws molten metal from a molten metal furnace into the ladle and moves the ladle so as to pour the drawn molten metal into the injection sleeve;
a molten metal detection unit that detects the molten metal in the ladle before pouring into the injection sleeve,
The molten metal detection unit includes a displacement sensor that measures a surface width of the molten metal in the ladle,
The control unit is configured to acquire an amount of molten metal in the ladle based on a detection result of the molten metal detection unit,
The control unit is configured to obtain an amount of molten metal in the ladle based on the molten metal surface width measured by the molten metal detection unit.

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