Patent Description:
A semi-solid metal material exists a state in which liquid phase and spherical crystal grains are mixed in an appropriate ratio in a semi-solid temperature range, and may refer to as a metal material that can be deformed even with a small force due to a thixotropic property and have excellent fluidity so as to be easy to be processed by molding like a liquid phase. Since the semi-solid metal material generally has fluidity at a lower temperature than liquid metal, the temperature of an exposed casting equipment can be lowered than the temperature of the liquid metal, and thus the life of the casting equipment can extend. In addition, when the semi-solid metal material is extruded, since turbulence thereof is less generated than in the liquid state, the mixing of air during casting can be reduced, and with a semi-solid state, contraction during solidification is small. As a result, workability is improved, and a product can be reduced in weight, so that the semi-solid metal material can be applied to a new material molding field.

As one of the casting methods that can use a semi-solid metal material, semi-solid die-casting is a casting method in which molten metal is pressed into a mold having a predetermined hollow part shape and casted by being pressurized until the molten metal is solidified. As a representative example of the semi-solid die-casting, there is a horizontal die clamping vertical shot squeeze casting (HVSC) method in which a sleeve injected with molten metal is inserted through a lower part of the mold.

As a method of performing structure control of the semi-solid molten metal by applying electromagnetic stirring to the above-described semi-solid die-casting apparatus to generate an electromagnetic field into the molten metal, the technique in which an electromagnetic induction coil is provided on an outer circumferential surface of a sleeve has been disclosed in <CIT>.

However, when the electromagnetic induction coil is provided on the outer circumferential surface of the sleeve and the sleeve is docked to the mold, a portion or more of the electromagnetic induction coil is inserted into the mold, and the electromagnetic induction coil may be damaged by the mold during the process. As such, a problem may occur with electromagnetic application for controlling the structure of the molten metal, which may affect the quality of castings. In addition, since the electromagnetic induction coil should be replaced for each replacement of the sleeve, a problem of increasing process cost may occur.

Conventional electromagnetic stirring members are disclosed in <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and the present disclosure is intended to propose a two-segment electromagnet semi-solid die-casting apparatus and a die-casting method using the same, which are configured to prevent impacts and damages to a two-segment electromagnet stirring member during coupling and separating of a sleeve and a mold and to efficiently provide electromagnetic vibrations to molten metal in the sleeve to control the structure of the molten metal.

Another objective of the present disclosure is to provide a two-segment electromagnet semi-solid die-casting apparatus and a die-casting method using the same, which are configured to improve an injection process by providing a two-segment electromagnet stirring member which is operated in conjunction with a movable mold and a fixed mold, regardless of replacement of a sleeve.

The objective of the present disclosure is not limited to the above-described objectives, and other objectives of the present disclosure not mentioned will be clearly understood by those skilled in the art from the subsequent description.

The present invention is directed to subject matter as defined in the appended set of claims. The scope of the present invention is defined by independent claims <NUM> and <NUM>, and further embodiments of the invention are specified in dependent claims <NUM>, <NUM> and <NUM>-<NUM>.

According to the embodiment of the present disclosure, the two-segment electromagnet semi-solid die-casting apparatus and the die-casting method using the same can prevent impacts and damages to the two-segment electromagnet stirring member when the sleeve is coupled to and separated from the mold member and can efficiently provide electromagnetic vibrations into the molten metal located in the sleeve to control the structure of the molten metal.

Furthermore, the first electromagnetic stirring part and the second electromagnetic stirring part are respectively located at the lower portions of the movable mold and the fixed mold and thus the two-segment electromagnet stirring member operated in conjunction with mold closure and mold opening of the movable mold and the fixed mold. Accordingly, the two-segment electromagnet stirring member can be coupled to or separated from each other regardless of replacement of the sleeve, so that maintenance can be easily performed and the injection process can be improved.

Hereinbelow, exemplary embodiments of the present disclosure will be described in detail with reference to accompanying drawings. Therefore, the present disclosure is not limited to the embodiments described below and may be embodied in other forms. Furthermore, in the drawings, lengths, thicknesses, etc. of layers and regions may be exaggerated for convenience description. Throughout the specification, the same reference numerals will refer to the same or like parts.

<FIG> is a perspective view showing coupling and separating of a two-segment electromagnet stirring member according to an embodiment of the present disclosure. <FIG> is a top view showing the coupling of the two-segment electromagnet stirring member according to the embodiment of the present disclosure. <FIG> is a side view showing docking of a sleeve of a two-segment electromagnet semi-solid die-casting apparatus according to the embodiment of the present disclosure. <FIG> is a side view showing undocking of the sleeve of the two-segment electromagnet semi-solid die-casting apparatus according to the embodiment of the present disclosure. <FIG> is a sectional view showing stirring of molten metal of the two-segment electromagnet semi-solid die-casting apparatus according to the embodiment of the present disclosure. <FIG> are sectional views showing a two-segment electromagnet semi-solid die-casting process according to an embodiment of the present disclosure. <FIG> is a process flowchart showing a two-segment electromagnet semi-solid die-casting method according to an embodiment of the present disclosure.

Referring to <FIG>, according to an embodiment of the present disclosure, a two-segment electromagnet stirring member <NUM> includes a plurality of magnetic field generation parts <NUM> therein and may be provided to be divided into a first electromagnetic stirring part <NUM> and a second electromagnetic stirring part <NUM>. The first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> are coupled to each other in a ring shape to surround an outer circumferential surface of the sleeve to perform electromagnetic stirring to the molten metal in the sleeve, and are coupled to each other to locate the magnetic field generation parts <NUM> at the radially equal gaps around the sleeve.

As the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> of the ring-shaped two-segment electromagnet stirring member <NUM> having a hollow portion at the center portion are coupled to each other, a casing 200a of the two-segment electromagnet stirring member <NUM> may be provided. The casing 200a may be formed in a ring shape including an inner wall <NUM> into which a sleeve <NUM> of an injection member <NUM> is inserted and an outer wall <NUM> spaced apart from the inner wall <NUM>. Furthermore, in order to protect the plurality of magnetic field generation parts <NUM> located in the casing 200a from the outside space, the casing 200a may have a structure in which all of upper and lower portions of regions between the inner wall and the outer wall and coupling surfaces of the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> are sealed, and the casing 200a may be formed of a non-magnetic material in order not to affect a magnetic field formed by the magnetic field generation parts <NUM>. Moreover, the periphery of the magnetic field generation parts <NUM>, for example, a cooling passage hole <NUM> is located in an internal part of the outer wall <NUM> to provide a passage of a hose through which a coolant is moved, so that overheating of the magnetic field generation parts <NUM> may be prevented. In some cases, the cooling passage hole <NUM> may serve as the passage through which a power cable providing power of the magnetic field generation parts <NUM> passes.

Each of the magnetic field generation parts <NUM> includes a core and a coil wrapping the core, and the magnetic field generation parts <NUM> may be arranged at the radially equal gaps on the sleeve <NUM> as a center shaft, i.e., at the circumferentially equal gaps. Each of the magnetic field generation parts <NUM> is applied with a current clockwise or counterclockwise to generate a magnetic field, and by the magnetic field, molten metal A located in the sleeve <NUM> may be vibrated successively along a circumferential direction of the sleeve <NUM> so that a microstructure may be controlled. In other words, when a magnetic flux of the magnetic field formed through the magnetic field generation parts <NUM> exerts an impact on the inside portion of the molten metal A, a part of the molten metal A is vibrated vertically and thus vertical intermittent vibration stirring may be performed without stirring such as rotating. Therefore, without rotation movement accompanied by turbulence of the molten metal, vibration movement accompanied by shaking of the molten metal is generated, so that intermittent vibration of the molten metal generated by the magnetic field impact may inhibit generation of dendrite, and the microstructure is controlled, thereby preventing the outside air that may be introduced when rotational stirring is performed by the electromagnetic field.

Referring to <FIG>, the two-segment electromagnet semi-solid die-casting apparatus <NUM> may include a mold member <NUM> including a movable mold <NUM> and a fixed mold <NUM>, the injection member <NUM> including the sleeve <NUM> and a plunger <NUM> and injecting the molten metal into the mold member <NUM>, and the two-segment electromagnet stirring member <NUM> including the first electromagnetic stirring part <NUM> located at one end of the movable mold <NUM> and moved in conjunction with the movable mold <NUM> and the second electromagnetic stirring part <NUM> located at one end of the fixed mold <NUM>. As the movable mold <NUM> is moved, the first electromagnetic stirring part <NUM> is moved to be coupled to the second electromagnetic stirring part <NUM> to surround the outer circumferential surface of the sleeve <NUM>, and the two-segment electromagnet stirring member <NUM> performs electromagnetic stirring to the molten metal A located in the sleeve <NUM>.

When describing the structure in detail, as the movable mold <NUM> is moved in a first direction toward the fixed mold <NUM>, the mold member <NUM> is closed in mold as shown in <FIG>, thereby having a cavity <NUM> in a shape of a product, and in order to eject a product B, the movable mold <NUM> is moved in a second direction, and thus the mold member <NUM> may be open in mold as shown in <FIG>.

As shown in <FIG>, the two-segment electromagnet stirring member <NUM> includes the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM>, and the first electromagnetic stirring part <NUM> is located at a lower end of the movable mold <NUM> and is moved in a first or second direction together with the movable mold <NUM> in conjunction with the movable mold <NUM>, thereby being coupled to or separated from the second electromagnetic stirring part <NUM> located at a lower end of the fixed mold <NUM>. Therefore, as the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> are respectively located at the lower ends of the movable mold <NUM> and the fixed mold <NUM> to provide the two-segment electromagnet stirring member <NUM> that is coupled to or separated from each other in conjunction with mold closure or mold opening of the movable mold <NUM> and the fixed mold <NUM>, regardless of replacement of the sleeve <NUM>, the two-segment electromagnet stirring member <NUM> may be coupled to or separated from each other separately from the injection member <NUM>, so that maintenance can be easily performed and an injection process can be improved.

The two-segment electromagnet stirring member <NUM> may include a cover part <NUM> to protect the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> from the outside space after ejection of the product from the mold member <NUM>. Therefore, as shown in <FIG>, when the mold member <NUM> is open in mold to eject the product B, clean the movable mold <NUM> and the fixed mold <NUM>, and coat a releasing agent, the cover part <NUM> is located outside the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> so as to protect the two-segment electromagnet stirring member <NUM> from a cleaning agent and the releasing agent.

At this point, the two-segment electromagnet semi-solid die-casting apparatus <NUM> may include a product ejecting member (not shown) that ejects the product B manufactured from the mold member <NUM>, and after ejection of the product B from the mold member <NUM>, and may include a cleaning nozzle member <NUM> cleaning the fixed mold <NUM> and the movable mold <NUM>. For example, the cleaning nozzle member <NUM> may include a nozzle <NUM> spraying the cleaning agent and an arm <NUM> connected to the nozzle <NUM> and moving the nozzle <NUM> upward, downward, forward, and rearward.

As shown in <FIG>, the injection member <NUM> may be rotated at a predetermined angle and the sleeve <NUM> may be tilted, and after the molten metal is injected into the tilted sleeve <NUM>, as shown in <FIG>, the injection member may stand upright and then be inserted into the mold member through a lower end of the mold member <NUM>. For example, a rotation support shaft <NUM> may be provided at a lower end of the injection member <NUM>, and a rotating driving cylinder <NUM> may be provided at one side portion of the injection member <NUM>. When the rotating driving cylinder <NUM> is operated to allow a cylinder rod 350a to extend, the injection member <NUM> is rotated at the predetermined angle on the rotation support shaft <NUM> and the sleeve <NUM> may be tilted at a predetermined angle, and the molten metal A may be injected into the tilted sleeve <NUM>. When injecting of the molten metal A is completed, the cylinder rod 350a is contracted and the sleeve <NUM> stands upright together with the injection member <NUM> and may be inserted into the mold member <NUM> through the lower end of the mold member <NUM>. In other words, as the movable mold <NUM> is moved the first direction, the movable mold <NUM> is coupled to the fixed mold <NUM>, the mold member <NUM> is closed in mold and the cavity <NUM> is provided in a shape of a product, and simultaneously, as the first electromagnetic stirring part <NUM> is moved in the first direction in conjunction with the movable mold <NUM>, and the first electromagnetic stirring part <NUM> may be coupled to the second electromagnetic stirring part <NUM>. At this point, the sleeve <NUM> is inserted into the mold member <NUM> through the lower end of the mold member <NUM> and the sleeve <NUM> may be docked to the mold member <NUM> while being coupled to the mold member <NUM> such that the inner wall <NUM> of the two-segment electromagnet stirring member <NUM> surrounds the outer circumferential surface of the sleeve <NUM>, and the two-segment electromagnet stirring member <NUM> may perform electromagnetic stirring to the molten metal A located in the sleeve <NUM>. Therefore, when the sleeve <NUM> is docked or undocked with respect to the mold member <NUM>, impacts and damages to the two-segment electromagnet stirring member <NUM> can be prevented, and as such, electromagnetic vibration is efficiently provided into the molten metal A located in the sleeve <NUM>, so that improved quality of the molded product B can be maintained constant by controlling the structure of the molten metal A.

The injection member <NUM> includes a coupling-type sleeve removing tool (not shown) located at one end of an injection rod <NUM>, and as the sleeve removing tool pushes the sleeve <NUM> upwards, the sleeve <NUM> may be uncoupled from the injection member <NUM>. Therefore, during the injection process, even when defects or damages occur to the sleeve <NUM>, it is possible to efficiently replace the sleeve <NUM> with the sleeve removing tool, which is an advantage. Furthermore, regardless of the replacement process of the sleeve <NUM>, the two-segment electromagnet stirring member <NUM> is provided separately from the injection member <NUM>, so that maintenance can be easily performed and an injection process can be improved.

Moreover, the two-segment electromagnet semi-solid die-casting apparatus <NUM> may include a sleeve releasing jig (not shown) located at an upper portion of the injection member <NUM>, and as the sleeve <NUM> pushed upwards by the sleeve removing tool and the sleeve releasing jig are coupled to each other, the sleeve <NUM> may be separated from the injection member <NUM>. Therefore, the sleeve replacement operation can be efficiently performed.

Referring to <FIG>, according to the embodiment of the present disclosure, a two-segment electromagnet semi-solid die-casting method includes injecting the molten metal A into the sleeve <NUM> of the injection member <NUM> first, at S110. The injecting the molten metal into the sleeve <NUM> by the injection member may be performed by rotating the injection member <NUM> at the predetermined angle to tilt the sleeve <NUM> (a), and injecting the molten metal A into the tilted sleeve <NUM> (b), and then making the injection member stand upright (c). For example, when the rotating driving cylinder <NUM> provided at one portion of the injection member <NUM> is operated to extend the cylinder rod 350a, the injection member <NUM> is rotated at the predetermined angle on the rotation support shaft <NUM> provided at the lower end of the injection member <NUM>, so that the sleeve <NUM> may be tilted at the predetermined angle. After then, when the molten metal A is injected into the tilted sleeve <NUM> and injection of the molten metal A is completed, the cylinder rod 350a is contracted and the sleeve <NUM> may stand upright together with the injection member <NUM>.

Next, the movable mold <NUM> of the mold member <NUM> is moved in the first direction to be coupled to the fixed mold <NUM> to be closed in mold (c), and the first electromagnetic stirring part <NUM> located at one end of the movable mold <NUM> is moved in conjunction with the movable mold <NUM> and may be coupled to the second electromagnetic stirring part <NUM> located at one end of the fixed mold <NUM>, at S120. At this point, the injecting of the molten metal into the sleeve <NUM> at S110 and the coupling of the mold member <NUM> and the two-segment electromagnet stirring member <NUM> at S120 may be performed simultaneously, as shown in <FIG>.

The coupling of the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> may be performed such that the plurality of magnetic field generation parts <NUM> is located at the radially equal gaps around the sleeve <NUM>. The first electromagnetic stirring part <NUM> may be coupled to the second electromagnetic stirring part <NUM> to form the ring-shaped two-segment electromagnet stirring member <NUM> having a hollow portion. At this point, the two-segment electromagnet stirring member <NUM> may have the casing 200a as the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> are coupled to each other. The casing 200a may be formed in a ring shape including the inner wall <NUM> into which the sleeve <NUM> of the injection member is inserted and the outer wall <NUM> spaced apart from the inner wall <NUM>. Furthermore, in order to protect the plurality of magnetic field generation parts <NUM> located inside the casing 200a from the outside space, the casing 200a may be formed such that the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> may be coupled to each other so as to seal the magnetic field generation parts <NUM>.

Next, the sleeve <NUM> is inserted into the mold member <NUM> through the lower portion of the mold member <NUM> while passing through the hollow portion of the two-segment electromagnet stirring member <NUM>, and the two-segment electromagnet stirring member <NUM> located to surround the outer circumferential surface of the sleeve <NUM> may perform electromagnet stirring with respect to the molten metal at S130. In other words, when the sleeve <NUM> passes through the hollow portion formed by the inner wall <NUM> of the casing and is inserted into the mold member <NUM>, the two-segment electromagnet stirring member <NUM> may start generating electromagnetism (d). In the magnetic field generation parts <NUM> arranged at the radially equal gaps on the sleeve <NUM> as the center shaft, i.e., arranged at circumferentially equal intervals, each of the magnetic field generation parts is applied with a current clockwise or counterclockwise to generate a magnetic field, and the molten metal A located in the sleeve <NUM> is vibrated in a circumferential direction of the sleeve <NUM> sequentially by the magnetic field so that the microstructure of the molten metal A. In other words, the magnetic flux of the magnetic field formed by the magnetic field generation parts exerts an impact on the inside portion of the molten metal, and a part of the molten metal is vibrated vertically, so that vertical intermittent vibration stirring may be performed without stirring such as rotating. Therefore, without rotation accompanied by turbulence of the semi-solid molten metal, vibration movement accompanied by shaking of the molten metal is generated, so that intermittent vibration of the molten metal generated by the magnetic field impact may inhibit generation of dendrite, and the microstructure is controlled, thereby preventing the outside air that may be introduced when rotational stirring is performed by the electromagnetic field.

Next, the plunger <NUM> is moved the electromagnetic-stirred molten metal A may be injected into the mold member <NUM> (e) and may be pressurized (f) at S140. In other words, as the injection rod <NUM> is raised and thus the plunger rod coupled to an end of the injection rod <NUM> is raised, the plunger <NUM> may inject the molten metal A into the cavity <NUM> of the mold member <NUM> (e), and the two-segment electromagnet stirring member <NUM> may maintain magnetic field generation until injection into the cavity <NUM> is completed. When pressuring the molten metal into the mold member <NUM> starts with completion of upward movement of the plunger <NUM> (f), electromagnetism generation of the two-segment electromagnet stirring member <NUM> may be completed.

Next, the mold member <NUM> is open in mold and the product B may be ejected from the mold member <NUM> at S140. When formation of the product is completed, the plunger <NUM> is lowered, and the injection member <NUM> may be undocked from the mold member <NUM> (g). After then, as the movable mold <NUM> is moved in the second direction, the movable mold <NUM> is separated from the fixed mold <NUM> so that the mold member <NUM> may be open in mold (h), and the first electromagnetic stirring part <NUM> is also separated from the second electromagnetic stirring part <NUM> in conjunction with movement of the movable mold <NUM>, and may be moved in the second direction together with the movable mold <NUM>. Furthermore, the injection member <NUM> may be tilted at the predetermined angle (i).

After then, the product ejecting member located at one side portion of the mold member is operated and the product may be ejected (j), and the movable mold and the fixed mold may be cleaned (k), and the releasing agent may be coated at S160.

After the ejecting of the product B, before the cleaning of the mold member <NUM>, the method may include moving the cover part <NUM> to the outside space of the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> to protect the two-segment electromagnet stirring member <NUM> at S150. In order to prevent the cleaning agent sprayed during cleaning of the mold member <NUM> and a chemical sprayed during coating of the releasing agent to affect the two-segment electromagnet stirring member <NUM>, before the mold member <NUM> is cleaned (k), the cover part <NUM> is moved, so that the outside space of the two-segment electromagnet stirring member <NUM> may be protected.

Furthermore, the cleaning nozzle member <NUM> is provided above the mold member <NUM>, so that after the product is ejected from the mold member <NUM>, cavity regions of the fixed mold <NUM> and the movable mold <NUM> may be cleaned. In this case, the method may include cleaning the tilted sleeve <NUM> by using a sleeve cleaning member <NUM>.

According to the embodiment of the present disclosure, the two-segment electromagnet semi-solid die-casting apparatus and the die-casting method using the same can have the advantage of controlling the structure of the molten metal while preventing impacts and damages to the two-segment electromagnet stirring member <NUM> during docking and undocking of the sleeve <NUM> with respect to the mold member <NUM> and efficiently providing electromagnetic vibration into the molten metal A in the sleeve <NUM>.

Furthermore, as the first electromagnetic stirring part <NUM> and the second electromagnetic stirring part <NUM> are respectively located at the lower portions of the movable mold <NUM> and the fixed mold <NUM> and the two-segment electromagnet stirring member <NUM> operated in conjunction with mold closure and mold opening of the movable mold <NUM> and the fixed mold <NUM> is provided, regardless of replacement of the sleeve <NUM>, the two-segment electromagnet stirring member <NUM> can be coupled to or uncoupled from each other, so that the injection process can be improved.

Claim 1:
A two-segment electromagnet semi-solid die-casting apparatus (<NUM>) comprising:
a mold member (<NUM>) comprising a movable mold (<NUM>) and a fixed mold (<NUM>);
an injection member (<NUM>) comprising a sleeve (<NUM>) and a plunger (<NUM>) and configured to inject molten metal (A) into the mold member (<NUM>); and
a two-segment electromagnet stirring member (<NUM>) comprising a first electromagnetic stirring part (<NUM>) and a second electromagnetic stirring part (<NUM>), the first electromagnetic stirring part (<NUM>) being located at one end of the movable mold (<NUM>) and being configured to be moved in conjunction with the movable mold (<NUM>) and the second electromagnetic stirring part (<NUM>) being located at one end of the fixed mold (<NUM>),
wherein the first electromagnetic stirring part (<NUM>) is configured to be moved with movement of the movable mold (<NUM>) to be coupled to the second electromagnetic stirring part (<NUM>) to surround an outer circumferential surface of the sleeve (<NUM>), and the two-segment electromagnet stirring member (<NUM>) is configured to perform electromagnetic stirring to the molten metal (A) located in the sleeve (<NUM>).