JP2014140857A - Molten metal leakage detection mechanism of casting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten metal leakage detection mechanism of a casting device in which the detection accuracy of molten metal leakage can be enhanced and the false detection can be effectively suppressed.SOLUTION: A conducting wire 23 is electrically isolated from a metallic die base 12 before a molten metal comes into contact therewith. However, a non-heat-resistant insulating layer 25 is melted by a leakage molten metal 14, and an electrical connection state is formed between the die base 12 and the conducting wire 23 exposed from a window part 26 formed in a heat resistant insulating layer 24 through the molten metal 14 coming into contact therewith. Accordingly, the electrical connection state is detected with a detection circuit 22 as electric resistance reduction (increase in the amount of current under a constant pressure), and stops injection work of the molten metal 14 to a casting mold 11 by turning on a lamp 22a and transmitting a stop signal to a control unit.

Description

  The present invention relates to a detection mechanism that detects that a molten metal leaks from between molds of a low-pressure casting apparatus.

  Casting has a higher degree of freedom in the shape that can be molded compared to mechanical processing and plastic processing, etc., and is superior in cost, so it is used for manufacturing metal products in various fields including automobiles, ships and machine tools. It has been.

  Thus, casting is a very good molding technique, but on the other hand, it is necessary to pay attention not only to its safety but also to productivity during casting operations.

In order to prevent the molten metal injected into the mold from leaking from the parting line part of the mold due to an initial defect in the mold alignment during casting, etc. A limit switch is provided in a cylinder that moves the mold forward and backward, and the limit switch detects the mold advance end, whereby molten metal is injected into the mold.

The casting apparatus is premised on that the molten metal does not leak from the closed mold. However, such a detection device has low detection accuracy and an error occurs. Furthermore, since some clearance is provided also in the movable part of a metal mold | die, it is difficult to prevent a molten metal leak completely.

  If this leaked molten metal comes into contact with the wiring arranged around the mold or the ram that raises or lowers the upper mold of the mold, the casting operation itself will be hindered. In the worst case, the casting operation is impossible. There is a fear. Therefore, it is necessary to detect a molten metal leak at an early stage. Patent documents 1-3 are known as prior art which performs early detection of this molten metal leak.

  In Patent Document 1, two electrodes covered with an insulating layer are arranged near the lower end of the inner side surface of a chamber for housing a mold, and when the molten metal leaks from the mold, the molten metal melts the insulating layer of the electrode. And the apparatus which detects a molten metal leak is disclosed by making two electrodes conduct | electrically_connect through a molten metal.

  Patent Document 2 includes a detection electrode that is disposed on a base and surrounds the entire circumference of the mold, and a detector that detects the presence or absence of an electrical connection between the detection electrode and the base. Partially covered with a heat-resistant insulating member, the portion of the detection electrode covered with the insulating member is in contact with the base, and the exposed portion of the detection electrode not covered with the insulating member is spaced upward from the base. A mechanism for detecting a molten metal leak by electrically connecting the detection electrode and the base by contacting the molten metal leaked from the mold with a portion of the detection electrode not covered by the insulating member. It is disclosed.

  In Patent Document 3, a metal dam member is provided on the base to prevent the molten metal from flowing out of the base through an insulating sheet, and the molten metal leaked from the mold climbs over the insulating sheet and reaches the weir. An apparatus is disclosed in which when a member is reached, the dam member and the base are connected with each other through the molten metal and the leakage of the molten metal is detected.

Japanese Patent No. 3092346 Japanese Patent No. 47879063 JP 2010-247157 A

  In the apparatus disclosed in Patent Document 1, since the molten metal leak cannot be detected until the molten metal reaches the inner wall of the chamber and straddles two electrodes, it takes time to detect the molten metal.

  In the mechanism disclosed in Patent Document 2, there is a certain gap between the base and the detection device, and the exposed detection portions of the detection electrodes and the portions covered with the insulating member are alternately arranged with a certain distance. Therefore, when the molten metal leaked from the mold first hits the coating part, the molten metal spreads along the detection electrode, and the molten metal leakage can be detected only when it contacts the exposed part. There is a problem that it takes time.

In the apparatus disclosed in Patent Document 3, since a wire (electrode) is not simply disposed around the mold, a dam member corresponding to each casting apparatus must be provided.
Implementation is cumbersome and there are also problems in terms of cost.

Further, in all of Patent Documents 1 to 3, the base and the detection electrode are electrically connected by contacting the conductive part such as molten metal dust (burr) generated during casting with the exposed part not covered with the insulating member. However, there is a problem of erroneous detection.
In any of Patent Documents 1 to 3, once an electrode detects a molten metal leak, it is difficult to repair the electrode and use it again as a detection device.

  It is an object of the present invention to provide a molten metal leakage detection mechanism capable of quickly responding to molten metal leakage while improving the accuracy of detection of molten metal leaking from a mold and effectively suppressing work failures due to erroneous detection. Objective.

  In order to solve the above problems, the molten metal leak detection mechanism of the casting apparatus according to the present invention has a detection electrode on a metal base on which a mold into which a molten metal is poured is installed so as to surround the mold all around. The sensing electrode is arranged such that the center conductor, the heat-resistant insulating layer that covers the outside of the conductor so that a part of the conductor is exposed, the outer surface of the heat-resistant insulating layer, and the molten metal come into contact with each other. It was set as the structure which consists of a non-heat-resistant insulating layer fuse | melted with the heat of a molten metal.

In order to expose the conducting wire, for example, a window is formed in the heat-resistant insulating layer. Further, the outermost non-heat-resistant insulating layer is not melted over the entire length by the heat of the molten metal, but only a part of the length is melted. On the other hand, the conductive wire and the outer heat-resistant insulating layer are not melted. It is preferable that only the non-heat-resistant insulating layer of the part can be repaired or replaced.
Furthermore, it is preferable to immediately notify the administrator or the like by a lamp or an alarm when there is a leak of molten metal.

  As described above, the present invention is (1) a detection electrode for detecting a molten metal leak is disposed on the base of the casting apparatus, and the molten metal leak is detected by electrical connection with the base, (2) (3) The detection electrode is covered with a heat-resistant insulating layer, and a window or a slit is formed on the side surface of the heat-resistant insulating layer. A detection electrode in which the outer shell (outermost) is covered with a non-heat-resistant insulating layer (heat-shrinkable) that melts with the heat of the molten metal is placed, and a leaked molten metal that melts the non-heat-resistant insulating layer is exposed from the heat-resistant insulating layer The point of contact with the sensing electrode and being electrically connected to the substrate, and (4) the non-heat-resistant insulating layer of the outer shell reduces the risk of false detection, and the non-heat-resistant insulating layer of the outer shell It has a holding power to the conductor covered with the inner heat-resistant insulating layer. It is to the point and technical features.

  That is, as feature (1), since the leak of the molten metal is detected by the electrical connection between the detection electrode and the base, it is not a device that prevents the molten metal leak itself, but the leaked molten metal Can be detected quickly, and even if a molten metal leak occurs, it can be kept to a minimum range.

Further, as described in the feature (2), the detection electrode is disposed so as to surround the mold (mold), so that it is possible to reliably detect the molten metal leak on the substrate.
In addition, since the outer shell of the detection electrode is covered with a non-heat-resistant insulating layer as described in feature (3), erroneous detection due to contact with a conductive object such as molten metal when a non-molten metal leaks. Can be avoided.

  Furthermore, as in feature (4), if a heat-shrinkable member is used for the non-heat-resistant insulating layer of the outer shell that contacts the base, the inner heat-resistant insulating layer is protected and the inner heat-resistant insulating layer is protected. It can be stuck so as not to peel off.

  Thus, according to the present invention, it is possible to provide a molten metal leakage detection mechanism of a casting apparatus that can increase the detection accuracy of molten metal leakage and can effectively suppress erroneous detection.

It is sectional drawing of the casting apparatus which concerns on one Embodiment of this invention, and the leak molten metal detection mechanism used for this casting apparatus. It is sectional drawing which showed the detection mechanism of the detection electrode. (A) is a radial sectional view of the detection electrode in a state where the molten metal is not in contact with the detection electrode, (b) is a radial sectional view of the detection electrode after the molten metal is in contact with the detection electrode, and (c) is a detection electrode. It is radial direction sectional drawing which shows another Example of this.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a casting apparatus 10 is used for low-pressure casting, and is installed under a mold 11 composed of upper and lower molds, a die base 12 on which the mold 11 is placed, and a die base 12. The main component includes a stalk 13 and a melting furnace 15 that accommodates the lower end of the stalk 13 and can hold the molten metal 14 therein.

  In the casting apparatus 10, the molten metal 14 is injected into the mold 11 through the stalk 13 by applying an air pressure in the melting furnace 15 to push down the molten metal surface 14 a in the melting furnace 15. Then, the molten metal 14 injected into the mold 11 is solidified after a predetermined time to form a cast product, and the casting operation is completed by removing the cast product by opening the mold.

  The molten metal leak detection mechanism 20 of the casting apparatus 10 includes a detection electrode 21 that is placed on the die base 12 and surrounds the mold 11 that is also placed on the die base 12 over the entire circumference.

  In this embodiment, the detection mechanism 20 includes a circuit 22 that detects whether or not the detection electrode 21 and the die base 12 are electrically connected to each other. The circuit 22 is provided with a lamp 22a and an alarm device for notifying the operator that the molten metal has leaked.

The detection electrode 21 includes a conductive wire (for example, a copper pipe) 23 at the center, a heat-resistant insulating layer (for example, a heat-resistant glass tape) 24 covering the conductive wire 23, and a non-heat-resistant insulating layer (for example, heat-shrinkable) covering the outermost shell. Insulation protection tube) 25.
Here, the heat resistance means that the molten metal does not melt even if it contacts the molten metal, and the non-heat resistant means that the molten metal contacts the molten metal.

  In this embodiment, the detection electrode 21 is shaped by matching the conductive wire 23 around the mold. A heat resistant insulating layer 24 is wound around the conductive wire 23, and a window portion 26 is formed with a cutter knife or the like. The heat-shrinkable non-heat-resistant insulating layer 25 is covered with the heat-shrinkable non-heat-resistant insulating layer 25 and heated with a dryer or the like, thereby bringing the heat-shrinkable non-heat-resistant insulating layer 25 into close contact with the detection electrode 21.

  In the molten metal leak detection mechanism 20 configured as described above, when the molten metal 14 injected into the mold 11 leaks out of the mold 11 for some reason, the leaked molten metal 14 travels on the die base 12 and is cast. 10 flows out. Here, since the detection electrode 21 surrounding the casting mold 11 is disposed on the die base 12, the molten metal 14 that flows on the die base 12 and flows out of the casting apparatus 10 constitutes the detection electrode 21. Contact the heat-shrinkable non-heat-resistant insulating layer 25.

  Before the molten metal contacts, as shown in FIG. 3A, the conductive wire 23 and the metal die base 12 are in an electrically insulated state. However, the non-heat-resistant insulating layer 25 is melted by the leaked molten metal 14, and as shown in FIG. 3B, the molten metal 14 that is in contact with the conductive wire 23 exposed from the window portion 26 formed in the heat-resistant insulating layer 24. Thus, an electrical connection state is formed between the die base 12 and the die base 12. Therefore, this electrical connection state is detected by the detection circuit 22 as a decrease in electrical resistance (increase in the amount of current under a constant pressure), and the lamp 22a is turned on or a stop signal is transmitted to the control unit to the mold 11. The injection work of the molten metal 14 is stopped.

As an example of the arrangement of the window portion 26, a plurality of the window portions 26 may be arranged linearly along the length direction of the conducting wire 23, arranged in a staggered manner, or randomly.
In particular, in the embodiment shown in FIGS. 3 (a) and 3 (b), an example is shown in which three windows 26 are arranged at equal intervals in the circumferential direction. For example, as shown in FIG. Two windows may be arranged opposite to each other in the direction.

  As described above, since the leakage of the molten metal 14 is detected by the electrical connection between the conductive wire 23 of the detection electrode 21 and the die base 12, the molten metal 14 flowing on the die base 12 reaches the conductive wire 23 at the same time. 14 leaks can be detected. Moreover, since the detection electrode 21 is disposed so as to surround the mold 11, the leakage can be reliably detected regardless of the leakage direction of the molten metal 14.

  Further, since the lead wire 23 forming the detection electrode 21 is completely covered with the heat-resistant insulating layer 24 and the heat-shrinkable non-heat-resistant insulating layer 25, the lead wire 23 forming the detection electrode 21 is not in contact with the die base 12. It is possible to avoid erroneous detection at the time of non-molten metal leakage.

  Further, the non-heat-resistant insulating layer 25 in contact with the die base 12 is made of a material having both insulating properties and heat shrinkability, and the window portion 26 in which the non-heat-resistant insulating layer 25 is formed on the heat-resistant insulating layer 24 is completely covered. Therefore, when the non-molten metal leaks, the die base 12 and the detection electrode 21 are always in an insulated state, and erroneous detection due to conductive dust and dust is prevented.

  Furthermore, when the molten metal 14 leaks, the molten metal 14 melts the non-heat-resistant insulating layer 25 of the outer shell and comes into contact with the conductive wire 23 through the window 26 of the heat-resistant insulating layer 24. Most of the conductive wire 23 is a heat-resistant insulating layer. 24, the conductor 23 is not melted, and the non-heat-resistant insulating layer 25 is wound around the portion again, so that it can be used for detection of molten metal leakage repeatedly, and cast for a long time. Safety of time can be ensured.

  In this embodiment, the detection electrode 21 is composed of the double insulating layers 24 and 25 that cover the conductor 23. Therefore, the direction and shape can be freely changed following the deformation of the conductive wire 23. Therefore, the arrangement mode can be freely set regardless of the shape of the die base 12 on which the detection electrode is to be arranged or the shape of the mold 11 to be enclosed. Further, with such a configuration, since each component is a commercially available product, the detection electrode 21 can be manufactured at a low cost.

Although one embodiment of the present invention has been described above, the molten metal leak detection mechanism according to the present invention can be variously modified within the scope of the present invention.
For example, regarding the detection electrode 21, in the above-described embodiment, the detection electrode is a detection electrode that surrounds the entire circumference. However, the detection electrode 21 may be divided according to circumstances. For example, although not shown, independent detection electrodes can be arranged in the longitudinal direction of the mold.

DESCRIPTION OF SYMBOLS 10 ... Casting apparatus 11 ... Mold 12 ... Die base 13 ... Stoke 14 ... Molten metal 14a ... Molten metal surface 15 ... Melting furnace 20 ... Detection mechanism 21 ... Detection electrode 22 ... Detection circuit 22a ... Lamp 23 ... Conducting wire 24 ... Heat-resistant insulating layer 25 ... Non-heat resistant insulating layer 26 ... Window

Claims (4)

A molten metal leakage detection mechanism of a casting apparatus in which a detection electrode is disposed on a metal base on which a mold into which a molten metal is poured is placed so as to surround the mold over the entire circumference,
The sensing electrode has a central conductor, a heat-resistant insulating layer that covers the outside of the conductor so that a part of the conductor is exposed, and covers the outside of the heat-resistant insulating layer. A molten metal leak detection mechanism of a casting apparatus, characterized by comprising a non-heat-resistant insulating layer.   The molten metal leak detection mechanism for a casting apparatus according to claim 1, wherein a window portion is formed in the heat-resistant insulating layer, and the conductive wire is exposed from the window portion. .   The molten metal leak detection mechanism of the casting apparatus according to claim 1 or 2, wherein the outermost non-heat-resistant insulating layer is partially exchangeable. 4. The molten metal leakage detection mechanism for a casting apparatus according to claim 1, wherein a circuit that issues a warning when the molten metal melts the non-heat-resistant insulating layer and the conductor and the base are electrically connected through the molten metal. The molten metal leak detection mechanism of the casting apparatus characterized by the above-mentioned.

Images